Periodontal Disease: Assessing the

Effectiveness and Costs of the Keyes

Technique

May 1981

NTIS order #PB81-221780
CASE STUDY # 5

THE IMPLICATIONS OF

COST-EFFECTIVENESS

ANALYSIS OF

MEDICAL TECHNOLOGY

MAY 1981

BACKGROUND PAPER #2: CASE STUDIES OF

MEDICAL TECHNOLOGIES

CASE STUDY #5: PERIODONTAL DISEASE: ASSESSING TH E

EFFECTIVENESS AND COSTS OF THE KEYES TECHNIQU E

Richard M. Scheffler, Ph. D.

Visiting Associate Professor of Health Economics

School of Public Health, University of California, Berkeley

Sheldon Rovin, D. D. S., M.S.

Chairperson, Department of Dental Care Systems

School of Dental Medicine, University of Pennsylvania, Philadelphia, Pa.

With commentary edited by: Allan J. Formicola, D. D. S., Dean, School of Dental and Oral Surgery,

Columbia University, New York

OTA Background Papers are documents that contain information believed to be

useful to various parties. The information undergirds formal OTA assessments or is

an outcome of internal exploratory planning and evaluation. The material is usually

not of immediate policy interest such as is contained in an OTA Report or Technical

Memorandum, nor does it present options for Congress to consider.
Library of Congress Catalog Card Number 80-600161

For sale by the Superintendent of Documents,

U.S. Government Printing Office, Washington, D.C. 20402
Foreword

This case study is one of 17 studies comprising Background Paper #2 for OTA’s

assessment, The Implication of Cost-Effectiveness Analysis of Medical Technology.

That assessment analyzes the feasibility, implications, and value of using cost-effectiveness and cost-benefit analysis (CEA/CBA) in health care decisionmaking. The major, policy-oriented report of the assessment was published in August 1980. In addition

to Background Paper #2, there are four other background papers being published in

conjunction with the assessment: 1 ) a document which addresses methodological

issues and reviews the CEA/CBA literature, published in September 1980; 2) a case

study of the efficacy and cost-effectiveness of psychotherapy, published in October

1980; 3) a case study of four common diagnostic X-ray procedures, to be published in

summer 1981; and 4) a review of international experience in managing medical technology, published in October 1980. Another related report was published in

September of 1979: A Review of Selected Federal Vaccine and Immunization Policies.

The case studies in Background Paper #2: Case Studies of Medical Technologies

are being published individually. They were commissioned by OTA both to provide

information on the specific technologies and to gain lessons that could be applied to

the broader policy aspects of the use of CEA/CBA. Several of the studies were specifically requested by the Senate Committee on Finance.

Because of particular circumstances regarding this case study on interventions for

periodontal disease, a commentary by a group of dental scientists and clinicians is

presented immediately folIowing the case study. The case study authors’ response is

presented after the commentary.

Drafts of each case study were reviewed by OTA staff; by members of the advisory panel to the overall assessment, chaired by Dr. John Hogness; by members of

the Health Program Advisory Committee, chaired by Dr. Frederick Robbins; and by

numerous other experts in clinical medicine, health policy, Government, and economics. We are grateful for their assistance. However, responsibility for the case studies remains with the authors.

Director

111
Advisory Panel on The Implications of

Cost= Effectiveness Analysis of Medical Technology

John R, Hogness, Panel Chairman

President, Association of Academic Health Centers

Stuart H. Altman

Dean

Florence Heller School

Brandeis University

James L. Bennington

Chairman

Department of Anatomic Pathology and

Clinical Laboratories

Children Hospital of San Francisco

John D. Chase

Associate Dean for Clinical Affairs

University of Washington School of Medicine

Joseph Fletcher

Visiting Scholar

Medical Ethics

School of Medicine

University of Virginia

Clark C. Havighurst

Professor of Law

School of Law

Duke University

Sheldon Leonard

Manager

Regulatory Affairs

General Electric Co.

Barbara J. McNeil

Department of Radiology

Peter Bent Brigham Hospital

Robert H. Moser

Executive Vice President

American College of Physicians

Frederick Mosteller

Chairman

Department of Biostatistics

Harvard University

Robert M. Sigmond

Advisor on Hospital Affairs

Blue Cross and Blue Shield Associations

Jane Sisk Willems

VA Scholar

Veterans Administration
OTA Staff for Background Paper #2

Joyce C. Lashof, Assistant Director, OTA

Health and Life Sciences Division

H. David Banta, Health Program Manager

Clyde J. Behney, Project Director

Kerry Britten Kemp, * Editor

Virginia Cwalina, Research Assistant

Shirley Ann Gayheart, Secretary

Nancy L. Kenney, Secretary

Martha Finney, * Assistant Editor

Other Contributing Staff

Bryan R. Luce Lawrence Miike Michael A. Riddiough

OTA Publishing

Leonard Saxe Chester Strobel*

Staff

John C. Holmes, Publishing Officer

John Bergling* Kathie S. Boss Debra M. Datcher

Patricia A. Dyson* Mary Harvey* Joe Henson

● OTA contract personnel.
Preface

This case study is one of 17 that comprise

Background Paper #2 to the OTA project on the

Implications of Cost-Effectiveness Analysis of

Medical Technology. * The overall project was

requested by the Senate Committee on Labor

and Human Resources. In all, 19 case studies of

technological applications were commissioned

as part of that project. Three of the 19 were specifically requested by the Senate Committee on

Finance: psychotherapy, which was issued separately as Background Paper #3; diagnostic Xray, which will be issued as Background Paper

#5; and respiratory therapies, which will be included as part of this series. The other 16 case

studies were selected by OTA staff.

In order to select those 16 case studies, OTA,

in consultation with the advisory panel to the

overall project, developed a set of selection

criteria. Those criteria were designed to ensure

that

●

●

●

●

●

●

●

as a group the case studies would provide:

examples of types of technologies by function (preventive, diagnostic, therapeutic,

and rehabilitative);

examples of types of technologies by physical nature (drugs, devices, and procedures);

examples of technologies in different stages

of development and diffusion (new, emerging, and established);

examples from different areas of medicine

(such as general medical practice, pediatrics, radiology, and surgery);

examples addressing medical problems that

are important because of their high frequency or significant impacts (such as

cost);

examples of technologies with associated

high costs either because of high volume

(for low-cost technologies) or high individual costs;

examples that could provide informative

material relating to the broader policy and

methodological issues of cost-effectiveness

or cost-benefit analysis (CEA/CBA); and

● Office of Technology Assessment, U.S. Congress, The lmplications of Cost-Effectiveness Analysis of Medical Technology, GPO

stock No. 052-003 -00765-7 (Washington, D. C.: U.S. Government

Printing Office, August 1980).

● examples with sufficient evaluable literature.

On the basis of these criteria and recommendations by panel members and other experts,

OTA staff selected the other case studies. These

16 plus the respiratory therapy case study requested by the Finance Committee make up the

17 studies in this background paper.

All case studies were commissioned by OTA

and performed under contract by experts in academia. They are authored studies. OTA subjected each case study to an extensive review

process. Initial drafts of cases were reviewed by

OTA staff and by members of the advisory

panel to the project. Comments were provided

to authors, along with OTA’s suggestions for

revisions. Subsequent drafts were sent by OTA

to numerous experts for review and comment.

Each case was seen by at least 20, and some by

40 or more, outside reviewers. These reviewers

were from relevant Government agencies, professional societies, consumer and public interest

groups, medical practice, and academic medicine. Academicians such as economists and decision analysts also reviewed the cases. In all,

over 400 separate individuals or organizations

reviewed one or more case studies. Although all

these reviewers cannot be acknowledged individually, OTA is very grateful for their comments and advice. In addition, the authors of

the case studies themselves often sent drafts to

reviewers and incorporated their comments.

:

I

vii
studies on gastrointestinal endoscopy and

on the Keyes technique for periodontal disease, commentaries from experts in the appropriate health care specialty have been

●

included, followed by responses from the

authors. 

The case studies were selected and designed to

fulfill two functions. The first, and primary,

purpose was to provide OTA with specific information that could be used in formulating

general conclusions regarding the feasibility and

implications of applying CEA/CBA in health

care. By examining the 19 cases as a group and

looking for common problems or strengths in

the techniques of CEA/CBA, OTA was able to

better analyze the potential contribution that

these techniques might make to the management

of medical technologies and health care costs

and quality. The second function of the cases

was to provide useful information on the specific technologies covered. However, this was

not the major intent of the cases, and they

should not be regarded as complete and definitive studies of the individual technologies. In

many instances, the case studies do represent excellent reviews of the literature pertaining to the

specific technologies and as much can stand on

their own as a useful contribution to the field. In

general, through, the design and the funding

levels of these case studies was such that they

should be read primarily in the context of the

overall OTA project on CEA/CBA in health

care.

Some of the case studies are formal CEAS or

CBAS; most are not. Some are primarily concerned with analysis of costs; others are more

concerned with analysis of efficacy or effectiveness. Some, such as the study on end-stage

renal disease, examine the role that formal

analysis of costs and benefits can play in policy

formulation. Others, such as the one on breast

cancer surgery, illustrate how influences other

than costs can determine the patterns of use of a

technology. In other words, each looks at evaluation of the costs and the benefits of medical

technologies from a slightly different perspective. The reader is encouraged to read this study

in the context of the overall assessment’s objectives in order to gain a feeling for the potential

role that CEA/CBA can or cannot play in health

care and to better understand the difficulties and

complexities involved in applying CEA/CBA to

specific medical technologies.

The 17 case studies comprising Background

Paper #2 (short titles) and their authors are:

Artificial Heart:, Deborah P. Lubeck and John P.

Bunker

Automated Multichannel Chemistry Analyzers:

Milton C. Weinstein and Laurie A. Pearlman

Bone Marrow Transplants: Stuart O. Schweitzer and C. C. Scalzi

Breast Cancer Surgery: Karen Schachter and

Duncan Neuhauser

Cardiac Radionuclide Imaging: William B.

Stason and Eric Fortess

Cervical Cancer Screening: Bryan R. Luce

Cimetidine and Peptic Ulcer Disease: Harvey V.

Fineberg and Laurie A, Pearlman

Colon Cancer Screening: David M. Eddy

CT Scanning: Judith L. Wagner

Elective Hysterectomy: Carol Korenbrot, Ann

B. Flood, Michael Higgins, Noralou Roos,

and John P. Bunker

End-Stage Renal Disease: Richard A. Rettig

Gastrointestinal Endoscopy: Jonathan A. Showstack and Steven A. Schroeder

Neonatal Intensive Care: Peter Budetti, Peggy

McManus, Nancy Barrand, and Lu Ann

Heinen

Nurse Practitioners: Lauren LeRoy and Sharon

Solkowitz

Orthopedic Joint Prosthetic Implants: Judith D.

Bentkover and Philip G. Drew

Periodontal Disease Interventions: Richard M.

Scheffler and Sheldon Rovin

Selected Respiratory Therapies: Richard M.

Scheffler and Morgan Delaney

These studies will be available for sale by the

Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.

Call OTA’s Publishing Office (224-8996) for

availability and ordering information.

viii
Case Study #5

Periodontal Disease: Assessing

the Effectiveness and Costs

of the Keyes Technique

Richard M. Scheffler, Ph. D.

Visiting Associate Professor of Health Economics*

School of Public Health

University of California, Berkeley

Sheldon Rovin, D. D. S., M.S.

Chairperson, Department of Dental Care Systems

School of Dental Medicine

University of Pennsylvania

Philadelphia, Pa.

AUTHORS’ ACKNOWLEDGMENTS

The authors would like to take this opportunity to thank the following individuals and organizations for their helpful suggestions on the earlier drafts of our report:

Dr. John F. Goggins, National Institute for Dental Research, National Institutes of

Health; Drs. Sigmund Socransky, J. Max Goodson, and Anne Tanner, Forsyth Dental

Center; Dr. Phillip Canon, Beth Israel Hospital; the staff of the National Center for

Health Services Research, Department of Health and Human Resources; and the staff

of Division of Dentistry, Department of Health and Human Resources.

*On leave from Department of Economics, George Washington University, Washington, D.C.
Contents

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. *..,

Periodontal Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traditional Technologies Used To TreatPeriodontal Disease. . . . . .

Nonsurgical Technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Surgical Technologies . . . . . . . . . . . . . . . . . . . . . . . ........0

The Keyes Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Evidence on the Effectiveness and Cost of the Keyes Technique

Data Collection. . . . . . . . . . . . . . . . . . . . . . ● **..** .***.***

The Effectiveness of the Keyes Technique . . . . . . . . . . . . . . . . .

The Delivery and Cost of the Keyes Technique. . . . . . . . . . . . .

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ● ***.** ....** .

Appendix A: Glossary of Dental Terms . . . . . . . . . . . . . . . . . . . . . .

Appendix B: Questionnaire Used To Collect Data . . . . . . . . . . . . . .

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Commentary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ● . , 

Authors’ Response to Commentary . . . . . . . . . . . . . . . . . . . . . . . . .

1.

2.

3.

4.

5.

Periodontal Disease

● ✎☛☛✎☛✎☛☛✎ ☛

** ****** *

● ☛ ☛☛☛☛☛✌✎☛ ✎

● ☛☛☛☛☛☛☛☛☛ ☛

● ☛ ✎☛☛☛☛✎✎☛ ☛
Case Study #5:

Periodontal Disease: Assessing

the Effectiveness and Costs

of the Keyes Technique

Richard M. Scheffler, Ph. D.

Visiting Associate Professor of Health Economics

School of Public Health

University of California, Berkeley

Sheldon Rovin, D. D. S., M.S.

Chairperson, Department of Dental Care Systems

School of Dental Medicine

University of Pennsylvania

Philadelphia, Pa.

INTRODUCTION

Of the $13.3 billion spent on dental care in

1978, approximately $350 million was spent on

treating periodontal disease (10,12). About $250

million of this was received by periodontists

(dentists who specialize in treating periodontal

disease); the remaining $100 million was received by general dental practitioners who delivered periodontal services. ’

A significant portion of expenditures for periodontal disease is for periodontal surgery. Such

surgery can be quite expensive. Two types of

periodontal surgery, mucogingival (gum) surgery and osseous (bone) surgery, for example,

per quadrant of the mouth often cost the patient

‘The $100 million estimate for general practitioners was derived

by multiplying national expenditures on dental care ($13.3 billion)

(12) by 0.78 percent, which is the percentage of total expenditures

collected by general dentists for periodontal services (10). The estimate of $250 million received by periodontists was derived by adding the average income of periodontists, $56,741, to the average

expenses for all dental practices, $56,303 (3) for 1976 and adjusting

for inflationary increases of 6 percent per year to express it in 1978

dollars. This sum ($126,144) was then multiplied by the approximately 2,000 periodontists practicing in 1978.

3
peroxide and baking soda and in some cases

drugs), and assessment of bacterial control by

regular microscopic examination of material

from the periodontal tissues. It involves the use

of water irrigation of the gums and other easily

learned hygiene procedures. Some claim that, if

properly used, the Keyes technique could reduce

dramatically the quantity of peridontal surgery performed.

In the next three parts of this case study, we

present layman’s definitions of periodontal disease; a description of the technologies currently

being used on a widespread basis to prevent and

treat periodontal disease and an assessment of

what is known about their effectiveness, based

on a review of the literature: and a description

of the Keyes rationale and how it may be used

for diagnosing, controlling, and preventing

periodontal disease.

Next, we present some preliminary results of

our recent study on 18 dental practices in the

Washington, D. C., Standard Metropolitan StaPERIODONTAL DISEASE

Tooth loss, in contrast to popular opinion

and mythology, is not a natural concomitant of

age—it is caused by disease processes. The disease processes of the periodontal, or supporting,

structures of the teeth, known collectively as

“periodontal disease” or “periodontal infect i on,” are responsible for 70 percent of all tooth

extraction and are the principal cause of tooth

loss (6,13,15,33).

Data show that some form of periodontal disease affects anywhere from 75 percent to virtually all of the adult population in the United

States, and a destructive form involving tissue

loss affects approximately one-third of the adult

population (6, 15,16,22,29). Periodontal disease

does afflict children, but it is more common and

more severe among adults. Although the disease

increases in prevalence and severity with age, it

is not the aging process that causes it; rather, it

is the length of time that the teeth and supportive tissues are exposed to the causative factors (21 ).

tistical Area (SMSA) that use the Keyes technique. With data on 190 patients and over 800

dental visits, we provide a short-term assessment of the effectiveness of the Keyes technique

and estimate the cost of delivering the Keyes

technique to the patients in our study. The results of our study provide new and useful data

on the Keyes technique, but larger scale and

long-term studies are needed before more definitive conclusions can

The final part of

sum mar y of some

Also discussed are a

be taken in order to

be drawn.

this study contains a brief

of our major conclusions.

few of the steps that need to

allow a complete cost-effectiveness analysis (CEA) of the Keyes technique.

We did not perform a CEA of the current technologies used for treating periodontal disease,

and no such analysis is available in the published literature. Hence, we are unable to compare the cost effectiveness of the Keyes technique to the cost effectiveness of the current

treatment of periodontal disease.

One of the difficulties in dealing with periodontal disease is its insidiousness. The onset of

disease is gradual. Afflicted individuals are generally symptomless for long periods of time.

Often patients have extensive disease, involving

the loss of supporting structures and formation

of deep pockets around the teeth, without being

uncomfortable or even aware of the problem.

All too often patients will have undiagnosed

periodontal disease for years even though they

have been regularly seen by a dentist.

The reasons for undiagnosed periodontal disease are several. Many dentists concentrate only

on restorative problems of the teeth and thus ignore or fail to recognize periodontal disease until it has progressed to an advanced stage. The

diagnosis of early or incipient periodontal

disease requires not only visual inspection, but

probing, staining for plaque, and radiographic

(X-ray) diagnosis; typical symptoms such as bad

breath, spontaneous bleeding, and pain tend to

occur only after the disease has progressed to
Case Study #5: Periodontal Disease: Assessing the Effectivenedd and Costs of the Keyes Technique ● 5

the moderate or advanced stage. Furthermore,

some dentists may not have been adequately

trained in diagnosing and treating periodontal

disease.

As is the case with many other chronic diseases, early diagnosis of periodontal disease affords a better chance for successful treatment. If

disease is detected early, therapy requires less

time and effort by the dentist, less discomfort to

the patient during therapy, less difficult oral

hygiene measures by the patient, and considerably less cost. Moreover, the destructive form

of periodontal disease first goes through a relatively innocuous inflammatory stage, and, if diagnosed and treated at that time, the disease is

in most instances easily reversible. The universality of periodontal disease is the most vexing

part of the problem, because in over 90 percent

of instances, such disease is potentially preventable by relatively inexpensive means known and

available today (13,28,29).

Periodontal disease is a disease complex, a

group of diseases placed under a single heading

for purposes of convention. The term “periodontal disease” is generally used to refer to

what are by far the two most prevalent periodontal diseases: gingivitis and periodontitis.

Gingivitis is inflammation of the gingiva (gum)

only and is generally considered a reversible

process (8). Periodontitis is inflammation of

both the gum and the other supporting structures of the teeth (i. e., the outer bone of the

tooth socket, the outer layer (cementum) of the

root of the tooth, and the soft tissues which attach these structures to one another). Periodontitis also connotes destruction or loss of the supporting structures of the teeth. Once destruction

takes place, complete regeneration of the affected tissues does not occur (8). The l0SS or

destruction of the supporting structures results

in the formation of pathologic spaces or pockets

around the teeth. 5 If this process continues, the

teeth lose their supporting structure, become

loose, and eventually have to be removed. Unfortunately, no accepted diagnostic method to

5

The normal space between the gum and the tooth is called a

SUlCUS. When this space deepens or extends past its normal boundary as a result of the inflammatory process, it is called a pocket.

determine at a given point in time whether the

destructive process is active or quiescent is currently available (14), a circumstance with significant therapeutic implications.

Experientially, most dentists feel that the progression of gingivitis to periodontitis is part of a

continuum (25), i.e., if gingivitis persists long

enough, it will inevitably progress into periodontitis. However, there is no documented scientific evidence for this view. It is known that

periodontitis does not develop in the absence of

gingivitis (25); and it does appear that, in most

instances, untreated gingivitis will progress into

periodontitis (25). At the same time, there is

great variability in the time it takes for progression to occur (gingivitis per se may exist for

many years); and in some instances, progression

does not occur at all (8,25). The distinction between gingivitis and periodontitis is emphasized, because gingivitis, by far the most common form of periodontal disease, is relatively

innocuous. Most important, it is potentially

reversible in a majority of instances. Uncomplicated by any other factor, gingivitis is usually

relatively easy to treat with methods that produce little or no discomfort to patients, and the

cost of treating gingivitis is a small portion of

what it costs to treat destructive periodontitis.

Bacteria] infection is the essential factor in the

initiation and propagation of periodontal disease (30,32). The exact mechanisms by which

the germs produce their deleterious effects remain undiscovered, but there is little doubt that

bacteria are the principal cause of periodontal

disease. The sine qua non in the etiology of periodontal disease is the presence of a microbial

population in the form of dental (or bacterial)

plaque. Dental plaque is a gummy bacterial substance that adheres to the teeth; it cannot be

seen by the naked eye, but is easily demonstrated by various stains. In the absence of

bacterial plaque, periodontal disease does not

occur; removal of such plaque halts the progression of, produces remission of, or reverses existing disease. Further evidence of the role of

bacteria in causing periodontal disease is the

fact that antimicrobial agents are often effective

in controlling such disease (25,32).
6 ● Background Paper #2: Case Studies of Medical Technologies

Bacterial populations in the mouth differ

under conditions of health and of disease, a

finding which has also has therapeutic implications (13). Furthermore, the same evidence

points to differences in the microbial composition of gingivitis and periodontitis. The importance of the role of bacteria in causing periodontal disease must be emphasized, because the

fundamental aim of periodontal treatment is to

control bacterial plaque or to facilitate its control by the patient, and the principal goal of

prevention is to inhibit its formation.

Faulty or improperly placed margins of dental

restorations (fillings) are recognized as a factor

contributing to periodontal disease (21,29). In

the face of these margins, plaque accumulates

readily, and the existing inflammatory process

is enhanced. What is not clear is whether faulty

margins actually initiate or just worsen the disease process. In either case, improper margins

have to be dealt with as a part of treatment.

There are other factors allegedly associated,

causally, with periodontal disease. A list would

include, in no relative order of importance,

malocclusion (malpositioning of the jaws with

respect to one another), faulty tooth position,

genetic predisposition, systemic disease such as

diabetes mellitus, and malnutrition. No further

discussion about these factors is warranted,

since they are not thought to be essential in

causing periodontal disease, and at most are

considered adjunctive to periodontal disease

(i.e., they might exacerbate preexisting periodontal disease) (21,25,34). Also, the consideration of these factors in a CEA of periodontal

therapy would be negligible.

TRADITIONAL TECHNOLOGIES USED TO TREAT

PERIODONTAL DISEASE

The traditional technologies used to treat

periodontal disease can be placed into two

broad general categories—nonsurgical and

surgical.

Nonsurgical Technologies

Plaque Control

There is a

ship between

and gingival

Daily plaque

conducive to .* *

well-documented, direct relationthe frequency of plaque removal

and periodontal health (5,29,31).

removal is considered optimally

gingival health. Obviously, individuals cannot have dental care professionals

remove plaque every clay. Patients must learn to

remove plaque by themselves, a task not terribly onerous, but requiring some knowledge

and mastery of technique.

The plaque control programs of periodontal

therapy are aimed at instructing patients in the

oral hygiene techniques that will remove plaque

and prevent it from accumulating in harmful

amounts. Basically, these oral hygiene techniques are the application of stain to detect

plaque and the brushing and flossing of teeth to

remove it. Professionally supervised practice of

these techniques is usually a basic part of periodontal therapy. The outcome of periodontal

therapy depends on how well the patient controls plaque formation. In the absence of plaque

control, any therapy is of little or no value

(4,23,26,29).

On the basis of the prevalence of periodontal

disease (6,16,22), it appears that, unfortunately,

most people do not effectively control plaque

formation, including many who have had extensive instruction and have been treated for destructive periodontal disease. The issue is not

simple. Plaque control is more than a question

of instruction about the proper methods. It requires individuals to change or modify their behavior so they not only know the correct methods, but are motivated to use them routinely.

Scaling and Root Planing

Scaling and root planing are professionally

applied mechanical techniques. Scaling is used

to remove calculus (hard deposits) from the

teeth, root planing to smooth the root surfaces,
Case Study #s: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 7

ostensibly to make the roots less susceptible to

microbial activity. The largest proportion of the

time and effort expended in treating patients

with periodontal disease is devoted to scaling

and root planing (11). In some instances, surgical techniques are used to make the roots more

accessible to this type of instrumentation.

Although it is generally assumed that the gingiva are irritated by the mere physical presence

of calculus, this assumption awaits substantiation by scientific data (9). The microbial plaque

covering the calculus is the noxious agent. Removal of gross or obvious calculus appears to

be indicated; however, what is not clear is

whether it is worthwhile to spend the time and

effort required to remove small amounts of calculus that are difficult to detect, particularly

since plaque re-forms in 24 to 36 hours (19,29).

There is also disagreement about the benefits

of root planing. The little evidence available

suggests that the primary rationale for root

planing is to remove calculus; root smoothness

may be inconsequential in retarding plaque formation (11,29). At any rate, the most important

determinant of periodontal health is the degree

to which patients exercise plaque control

(23,27,29).

Another issue relates to the frequency of prophylaxis (professional scaling) required to maintain periodontal health. A landmark study indicates that the optimal frequency is at 2-week intervals (5). However, other data suggest that

quarterly intervals are also beneficial, although

not as effective as 2-week intervals (29). Again,

the benefits of scaling are believed to be less important than the patient’s personal oral hygiene

and plaque control. Unfortunately, more people

rely on the dentist or hygienist for prophylaxes

than practice good plaque control themselves.

Thus, the issue of frequency must be examined,

particularly from a standpoint of cost effectiveness. On the basis of available evidence, prophylaxis at 2-week intervals would be cost prohibitive for most individuals. Moreover, given

current methods of dental practice, there is inadequate manpower to routinely clean people’s

teeth at 2-week intervals.

Correcting Margins of Restorations

Since improper margins of dental restorations

contribute either to the initiation or severity of

periodontal disease, the correction of such margins is an integral part of therapy. The most important reason for correcting improper margins

is to facilitate plaque control, because in the face

of an overhanging restoration, for example,

plaque removal is exceedingly difficult. Generally, correction in the form of reducing bulk or

smoothing is done at the time of scaling and

root planing; but it is a requirement of periodontal therapy regardless of when it is done.

Chemotherapy

Substantiation of the fact that micro-organisms are a primary causative factor in periodontal disease has sparked much interest in

chemotherapeutic control measures (1,20,29,

30). Some of the initial attempts to control periodontal disease with certain antimicrobial

agents have been successful, but these attempts

must be considered only trials. Essentially, insufficient evidence is available to warrant the

routine use of these agents (29). Furthermore, a

limitation of the studies thus far conducted is

that they have been short-term. Periodontal

disease is of long duration and requires what

amounts to a lifetime of effort in controlling

plaque formation; an antimicrobial agent may

suppress bacteria or reduce plaque formation in

a short-term clinical trial, but this does not

mean that it will do so effectively and safely,

without side-effects, for a long period of time.

Nonetheless, further chemotherapeutic experimentation is warranted. However, at this time,

chemotherapy is not considered a primary technology in the control of plaque or periodontal

disease.

‘Chemotherapy, the use of chemical agents—in this case antibiotics—to treat disease, is not an accepted, routine part of periodontal therapy. It is included here because the role of micro-organisms in causing periodontal disease has been shown only recently,

and the principal method of treating microbial diseases generally is

with these agents. As specific bacteria are identified as causative

agents, much more emphasis is likely to be placed on the use of

chemotherapy. The discussion of chemotherapy is also included

because of cost implications.
8 ● Background paper #.?: Case Studies of Medical Technologies

Surgical Technologies

Periodontal surgery, in one form or another,

is a common procedure used to eliminate the

pockets that occur in destructive periodontal

disease (24). Different surgical techniques are

used for different purposes. Eliminating pockets, making root surfaces more accessible to removing plaque, inducing reattachment of tissues, and restoring destroyed tissues are the

main clinical objectives of employing these techniques (7). In practice, two or more techniques

often are used together to achieve a specific

result.

Regardless of the objective of the specific surgical method, the fundamental rationale of periodontal surgery is to prolong the functional life

of the teeth. The ultimate success or failure of

the particular surgical method, therefore,

should be judged by the extent to which the

method conserves tooth life. Unfortunately,

there are few baseline data on which to make

objective evaluations. With only a few exceptions (7,23,24), the studies of the different

surgical methods are short term. Longitudinal

studies (longer than 5 to 10 years) required of

diseases having the apparent chronicity of periodontal disease are needed. Until such scientific

THE KEYES TECHNIQUE

Dr. Paul Keyes and associates have developed

and are testing a technology they believe suppresses plaque microbes and arrests, or markedly abates, the progression of destructive periodontal disease (17,18). This technology involves the use of a meticulous diagnostic and

therapeutic regimen, the latter involving the application of certain salt solutions in all instances, and periodic courses of systemic antibiotics when indicated. Therapeutic regimens

are based on microscopic sampling of plaque in

the pocket areas as a means of monitoring bacterial activity. An integral part of the Keyes program is to show the patient the actual bacteriologic activity in the periodontal tissues though

a microscope, the intent being to convince the

patient of the extent of the problem and to motistudies have been carried out, objective measurements of surgical effectiveness must remain

tentative at best.

Those studies that have been done do not

unequivocally point to one technique’s being

superior to another (7,23,24,27). Moreover, although the reasons for doing periodontal surgery can be supported experientially, scientific

evidence does not show that any of these surgical techniques alone is effective in prolonging

the life of the teeth. Periodontal surgery makes

no difference in the absence of reasonable oral

hygiene by patients combined with professional

maintenance (23,24,26,27). The surgery by itself

will not restore health to diseased periodontal

tissues.

In summary, we conclude that there is considerable controversy surrounding the efficacy of

the various surgical techniques used in the treatment of periodontal disease. It is also fair to

note that the emphasis on surgical technology

may be misplaced (29) and the type of surgery

that is performed is considered far less important than whether or not the teeth can be maintained in a state of good oral hygiene (4,23,24,

26,27).

vate him or her to help in its remediation. Oral

hygiene and plaque control instruction is given

in a slow, stepwise fashion over a 3- to 4-week

period. Patients are also advised to rinse their

mouths after eating, whenever possible, and to

use a pulsed-water irrigation device, such as a

Water Pik, once a day.

Earlier we stated that there is no diagnostic

method available to determine whether or not

destructive periodontal disease is in an active

state. The Keyes method purports to distinguish

active from inactive disease by assessing the

specific microbial population and inflammatory

process in the pocket area. Dr. Keyes asserts

what others believe but are not willing to assert

without more substantiating evidence—that the
Case Study #.5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 9

specific bacteria identified via the microscope

are predictors of pathologic status and that the

bacteria associated with disease differ from

those found in healthy periodontal tissues. With

the information obtained via microscopic examination, treatment is initiated which is aimed at

suppressing the microbial population and facilitating the patient in controlling plaque formation.

Although the Keyes method is still in the early

stages of being tested, Keyes has reported

marked improvement in patients he has treated

(18). It should be emphasized that the effectiveness of the Keyes method, like that of other

treatments, depends on the patient’s assiduously

following the prescribed plaque control program (18). If it turns out that the Keyes method

is as effective as its developers believe, then that

would mean, among other things, that the patients using the Keyes method are doing a better

job of controlling plaque than they would with

other technologies. That in itself would be a

most significant outcome.

Many individuals do not practice good oral

hygiene. Even patients who have undergone extensive periodontal surgery and have received

intensive oral hygiene instruction as a part of

therapy often do not exercise adequate plaque

contro; the recurrence rate of periodontal disease in such patients is high (24). If the Keyes

method proves more effective than others, that

will mean that something about this method

enables or makes it easier for patients to exercise

plaque control better than the other methods

used to date. It could be the Keyes method’s

slow, stepwise fashion of patient instruction.

Possibly, showing patients microbes taken from

their tissues under a microscope impresses the

nature of the problem upon the patients in a

more effective manner. This is only speculation,

and, of course, it is far too soon to tell if the

Keyes technique has lasting effect. Much more

evaluation—particularly long-term evaluation

—is needed. (In the next part of this case study,

we present the first systematic assessment of the

effectiveness of the Keyes technique in multiple

practice sites. )

Figure 1 shows some of the important similarities and differences between the Keyes and traditional technologies for treating periodontal

disease. The “traditional” technology is shown

in the lower half of the figure and the steps are

labeled by capital letters. The “Keyes” technology is shown in the upper half of the figure, with

the steps labeled by lower case letters.

Regardless of which technique will be applied

to an individual patient, all patients—those who

will be managed traditionally as well as those

who will not—initially go through about the

same diagnostic and treatment planning procedures. Once periodontal disease is diagnosed

(Aa), patients can be treated either by “traditional” methods or the “Keyes” method. At this

juncture, all patients with periodontal disease

receive oral hygiene instruction and extensive

tooth cleaning (scaling and root planing), see (B)

and (b) on the figure. A comparison of (B) and

(b) shows that the patients being treated by the

Keyes method also receive a microscopic examination and are placed on a regimen that includes salt-solution therapy.

In patients being treated by the “traditional”

method, a determination is then made of the

presence or absence of pockets (C). If there are

no pockets but disease is present (D), the patient

receives further tooth cleaning and hygiene instruction (B). If pockets are present, some form

of surgery is usually, but not always, performed

(E). After surgery, if disease persists or recurs

(D), the patient receives additional tooth cleaning and hygiene instruction (B). If no pockets

are present and the patient is in reasonable oral

health (F), a maintenance phase is begun (G).

In patients being treated by the “Keyes” method, by contrast, oral hygiene instruction and

bacteriologic monitoring continue (c), but there

is no surgery. If disease (d) persists, the patient

is generally placed for 2 weeks on a regimen of

antibiotics, 7and oral hygiene instruction, microscopic examination, and tooth cleaning are

continued (b). If the patient is in reasonable oral

health (f), a maintenance phase is begun (g).

The Keyes technology differs from the traditional method of treating periodontal disease in

three essential ways: 1 ) Microscopic diagnosis

‘Antibiotics may also be used in the traditional method, but are

not used as routinely.
I No periodontal

I

I

monitoring

I *

Health 1 (f)

● *

Traditional

and monitoring of microbial activity is the basis

for therapeutic decisions; 2) salt solutions are

used routinely and antibiotics are used often;

and 3) periodontal surgery to eliminate pockets

is used infrequently, since complete pocket elimination is not a goal of the Keyes method. The

Keyes method is founded on Keyes’ belief that

halting the progression of the destructive process and allowing natural healing to occur does

not depend on surgical elimination of the pocket, but does depend on controlling bacterial

activity.

in figure 1 are general, and some of the particular steps may differ, especially in the “traditional” technology. These differences or changes

depend on several factors, such as extent of disease, the patient’s overall health, the patient’s

ability or willingness to pay, and the personal

treatment philosophy of the practitioner. Also,

it should be reemphasized that the ultimate success of therapy, regardless of method, depends

more on how well the patient practices good

oral hygiene than on what the dentist does for

the patient.

It should be emphasized that the steps shown
OF THE KEYES TECHNIQUE

Data Collection

To perform our study of the effectiveness and

cost of the Keyes technique, we collected data in

1979 on 18 dental practices from the Washington, D. C., SMSA that currently use this technique. 8 Using written questionnaires, we collected data on each practice and on a selection of

the patients in each practice who are currently

being treated with the Keyes technique. ’

Data on 8 of the practices were obtained via a

mail survey, and data on the other 10 were collected by dental students. ’” All 18 of the dental

practices surveyed were owned and operated by

solo general practitioners. The average age of

these practitioners was 47. The average length

of time they had been in practice was almost 12

years; they had used the Keyes technique for

13.7 months on the average.

Using information from the patients’ records,

we completed a written questionnaire on about

10 patients in each practice who were beyond

their initial visit for the Keyes technique. 11 The

questionnaire used to collect data on individual

patients is reproduced in appendix B. Using this

questionaire, we obtained data relating to the

patient’s oral health status before treatment and

at the time the questionnaire was administered.

Data were also obtained on the services delivered to the patient during the first six visits and

the maintenance visit, on who delivered these

services, and in what amount of time. The

charges for each visit were also recorded. Usable

‘Currently, there are 26 dental practices using the Keyes technique in the Washington, D. C., SMSA. Except for the data collected at the National Institutes of Health by Keyes on his own

practice, no other data of this type are currently available.

“The data collection for the study was supported in part by a

grant (grant No. H.S.-O2577) from the National Health Care Management Center, Wharton School, University of Pennsylvania.

That center IS funded by the National Center for Health Services

Research, Office of the Assistant Secretary for Health, Department

ofHealth and Human Services.

IOA comparison of the data collected via mail and the data COllected by the dental students did not show any important statistical

differences. The data collected by the dental students were more

complete.

"In some practices, we were able to complete questionnaires on

more than 10 patients; in others, we had to settle for fewer.

data for our estimates were collected on 190 patients and over 800 dental visits. Approximately

63 percent of the patients were female. The average age of all patients was 42.

The Effectiveness of

the Keyes Technique

In order to demonstrate the effectiveness or

lack of effectiveness of the Keyes technology,

five measures were used as general indicators of

periodontal disease of the patients in the study

before and after treatment. All five oral health

indicators showed some improvement following

treatment (see table 1).

A number of the important indicators

changed dramatically. Bleeding of gums upon

probing, an indication of early or beginning

disease, dropped from 99 percent of the patients

showing it before treatment to 34 percent of the

patients showing it at the time the information

was obtained. Another important change was

the decrease from 65 to 9 percent in the number

of patients with loose teeth. This change is imTable 1 .—Periodontal Disease Indicators:

Effectiveness or Lack of Effectiveness

of the Keyes Technique

Percentage of patients

Status

before Current

Indicator treatment status

1. Bleeding on probing . . . . . . . . . . . 99% 34%

N = 185 N = 185

2. Suppuration. . . . . . . . . . . . . . . . . . 56 23

N = 185 N = 181

3. Mobile teeth. . . . . . . . . . . . . . . . . . 65 9

N = 178 N = 173

4. WBCS microscopically evident . . 9 4 78

N = 182 N = 172

5. Motile forms microscopically

evident . . . . . . . . . . . . . . . . . . . . . . 62 32

N = 170 N = 148
I2 ● Background paper #2 Case Studies of Medical Technologies

portant because loose teeth are an indication of

advanced disease, A “t” test on the difference

between the percentages before and after treatment for each of the periodontal disease indicators in table 1 was statistically significant at

the 0.01 level. Thus, these data indicate a significant overall improvement in dental health

for our study population.

Moreover, at the time our study was done, 65

percent of the 190 patients in the study population had gone from treatment to maintenance,

and only 35 percent required further treatment.

We also performed an analysis of the data over

time. This analysis included some of the patients

being treated and then maintained by the Keyes

method for more than 24 months. *2 In these patients, the indicators of oral health continued to

show almost the same level of improvement as

in patients treated and maintained for less time.

Furthermore, our analysis of the data concerning the effect of the Keyes technology on the

level of plaque control exercised by the patients

showed that improvement in plaque control had

occurred to the same extent as improvement in

the other indicators (see table 2). For example,

before treatment 93 patients were judged to

have below-average plaque control, but at the

time our data were collected only 12 patients

were rated in this manner. A chi square test

showed patient improvement in plaque control

(as indicated by the before and after data in

table 2) for all groups of patients to be statistically significant at the 0.01 level or greater.

(This finding does not apply to the group of patients who were above average in plaque control

before treatment. )

12 The data used for this analysis are not presented in this discussion.

Table 2.—Plaque Control by Patients

After treatment

Patient status Above Below

before treatment average Average average

Above average (2). . . . . . . . 2 0 0

Average (76). . , . . . . . . . . . 56 19 1

Below average (93). . . . . . . 42 39 12

Total (171). . . . . . . . . . . . 100 58 13

The Delivery and Cost of

the Keyes Technique

The Keyes technique involves the delivery of

10 basic procedures. These procedures and the

percentage of patients in our study population

receiving them during each visit to the dentist

are shown in table 3. The first visit usually involves a dental history (76 percent) and a medical history (84 percent). If histories are not provided during this visit, that usually indicates

that histories were provided at a visit prior to

beginning the Keyes technique. This is also the

case for radiographs and visual assessment.

During the first visit, over half the patients

undergo periodontal probing (7 I percent), a

microscopic examination (64 percent), and a

scaling (52 percent). About two-fifths of the patients receive periodontal pocket measurements

(40 percent) and almost one-sixth (16 percent)

receive root planing. Almost two-thirds of the

patients (64 percent) also receive plaque control

instruction during the first visit.

The percentage of patients receiving dental

histories, medical histories, and radiographs, as

expected, declines after the initial visit. Over the

next two visits (visits 2 and 3), the percentage of

patients receiving root planing and scaling increases. Later visits continue the use of scaling

and root planing, as well as plaque control instruction and probing. The maintenance visit

shows some increase in visual assessment, scaling, pocket measurement, and microscopic examinations. Clearly, the maintenance visit (except for the histories, diagnosis, and plaque control instruction) is somewhat similar to the initial visit in terms of the procedures performed.

To estimate the cost of producing the Keyes

technique, we began with data on the amount of

dentist and hygienist time used during each visit

(see table 4). The majority of this time is used to

instruct the patient in plaque control and provide maintenance. The first visit uses an average

of 28 minutes of dentist time and 24 minutes of

hygienist time. ’3 For later visits (visits 5 and 6,

13 lt is interesting to note that the estimate of the average dentist

time has a large standard deviation in comparison to the mean (coefficient of variation). A further analysis of the data showed that

there was a significant variation among the 18 dental practices, as

well as across the patients treated within each practice.
Case Study #5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 13

Table 3.—Mix of Services Delivered at Each Visit for the Keyes Technique

Percentage of patients (N)

Maintenance

Service Visit 1 Visit 2 Visit 3 Visit 4 Visit 5 Visit 6 visit

Dental history. . . . . . . . . . . . . . . . . . . . 76%

N = 184

Medical history. . . . . . . . . . . . . . . . . . . 84

N = 184

Radiographs. . . . . . . . . . . . . . . . . . . . . 71

N = 184

Visual assessment. . . . . . . . . . . . . . . . 97

N = 184

Periodontal probing. . . . . . . . . . . . . . . 71

N = 185

Pocket measurement . . . . . . . . . . . . . . 40

N = 185

Microscopic examination . . . . . . . . . . 64

N = 185

Scaling . . . . . . . . . . . . . . . . . . . . . . . . . 52

N = 184

Root planing . . . . . . . . . . . . . . . . . . . . . 16

N = 185

Plaque control instruction . . . . . . . . . 64

N = 185

Other . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

N = 185

1 %

N = 177

6

N = 177

10

N = 177

71

N = 177

62

N = 177

20

N = 177

62

N = 177

63

N = 177

33

N = 177

72

N = 176

30

N = 176

1 %

N = 158

N =6158

7

N = 158

71

N = 158

60

N = 158

17

N = 158

54

N = 158

66

N = 158

35

N = 158

54

N = 157

36

N = 157

0

N = 135

6%

N = 135

N =7135

70

N = 135

N=99 

14

N = 135

46

N = 135

62

N = 135

28

N = 135

44

N = 135

33

N = 135

0

N =99

4 %

N =99

5

N = 100

67

N =99

47

N =99

12

N = 100

47

N =99

N =6 9

N =1OO

37

N = 100

23

N = 100

0

N =69

1%

N =69

14

N =69

67

N =69

45

N =69

19

N =69

51

N =69

68

N =69

32

N =69

38

N =69

22

N =69

4%

N = 105

N 105

14

N = 105

84

N = 105

51

N = 105

32

N = 105

54

N = 104

83

N = 105

36

N = 105

26

N = 105

35

N = 105

N = number of observations.

Table 4.—Average Dentist and Hygienist Time Used for Each Visit for the Keyes Technique

Maintenance

Visit 1 Visit 2 Visit 3 Visit 4 Visit 5 Visit 6 visit

Dentist timea

. . . . . . . . . . . . . . . . . . . . 28 22 20 21 19 22 20

SD=22.46 SD=19.83 SD=18.1O SD=19.00 SD=16.84 SD=18.17SD=17.56

N = 173 N = 138 N = 135 N = 111 N =93 N =50 N =92

Hygienist timea. . . . . . . . . . . . . . . . . . 24 25 23 23 21 21 21

SD= 22.43 SD= 19.20 SD= 19.99 SD= 19.28 SD= 19.27 SD= 19.72 SD= 18.25

N = 140 N = 143 N = 117 N =99 N =69 N =53 N =83

SD= Standard deviation

N = mumber of observations.

a

Time in minutes.

and the maintenance visit), the amount of dentist time in each visit declines, while amount of

hygienist time remains quite stable. (For purposes of our cost calculation, we assumed that

the dentist time is spent with only one patient.

However, it is likely that some dentists are treating more than one patient at a time. If that is the

case, our estimates of the average variable cost

of production may be too high. )

To estimate the average variable cost (in 1979

dollars) of producing the Keyes technique, we

assume that the dental practice is already in

operation and that the only additional expenses

for producing the Keyes technique are the cost

of the phase-contrast microscope and the cost of

the dentist and hygienist time.14 The scope cost

is about $3,000, and we depreciate it over a 10-

year period. For the purpose of our estimates,

we allocate the cost of the scope to 100 patients

being treated by the Keyes technique per year at

$3 per visit.15 The cost of dentist time, based on

the yearly income of and hours worked by a

14 In a technical sense, once the scope is purchased, it is a fixed

cost and not a variable cost. Since the cost of the scope is modest,

deleting the cost from our estimate would have very little impact.

15 This estimate may be high, because dentists who use the Keyes

technique probably treat more than 100 patients a year. In any

event, the per unit cost of using the phase-contrast microscope is

small; thus, alternative methods of computing its cost will have a

small impact on our estimates.
general practitioner, is estimated at $25 per hour

(3). ” To estimate the cost of hygienist time, we

used the same costing procedure and added iS

percent for fringe benefits. This produced a cost

of $8 an hour for the hygienist time (3).17

To produce an estimate of the labor cost per

visit, we applied these hourly rates to the

minutes of time used by the dentist and hygienist. To this estimate, $3 was added for the use of

the phase-control scope to produce estimates of

the average variable cost of producing each visit

(see table 5). According to our estimates, the

average variable cost of producing the initial

visit is higher than that of producing subsequent

visits. The difference in average variable cost

mostly reflects the reduction of time spent by

the dentist and the different range of services

provided following the initial visit (table 4).

Data from our survey on the average charge

for each visit are presented in table 5. Again it is

interesting to note that the average charge is

highest for the initial visit. Moreover, for the

maintenance visit, the average variable cost as a

percentage of average charge is the lower than it

is for any of the first six visits. For the dentists

that charge for the Keyes technique on the basis

of the total treatment cost, the average charge

per case was slightly over $120. This charge per

case is comparable to the total charge, on a per

visit basis, of between five and six visits.

In addition to paying the dental charges for

the Keyes technique, the patient needs to purchase an electric toothbrush and electrical irrigating device at a total cost of $30 to $40. In

about half the cases treated by the Keyes technique in our data base, drugs were utilized, usually tetracycline. The cost for tetracycline per

prescription is between $8 and $10. In most instances, one or two prescriptions are required

for those patients using tetracycline. It is currently believed that after the patient has been

treated successfully by the Keyes technique, two

maintenance visits at an average charge of

about $26 per visit are required to ensure continued oral health (29).

The Keyes technique may have benefits in addition to the treatment and prevention of periodontal disease. In some patients, a benefit may

be a reduction in tooth loss. Furthermore, if surgery is avoided, the pain and discomfort associated with surgery are also avoided. By involving patients in improving their oral health, the

Keyes technique may improve their awareness

of dental disease and encourage their early use

of dental services, while the disease is still treatable, often at a reduced cost.

Table 5.— Estimates of the Average Variable Cost of Producing Each Visit and

the Average Charge per Visit for the Keyes Technique
CONCLUSION

Periodontal disease is a chronic disease that

affects over 90 percent of the adult population in

the United States (6, 15,16,22,29). Today, treatment of periodontal disease by dentists often involves surgery. The surgical procedures that are

used may be painful to the patient, and they

often carry with them postsurgical discomfort.

More importantly, our assessment of the scientific literature shows that the effectiveness of the

surgery alone in the treatment of periodontal

disease has not been adequately demonstrated.

The Keyes technique is so new that long-term

efficacy and effectiveness studies have not been

possible, although the evidence to date appears

promising. Our analysis, based on data from 18

general practices in the Washington, D. C.,

SMSA on 190 patients being treated with the

Keyes technique and over 800 visits, found a

measurable and statistically significant improvement in each of the five indicators of dental disease we employed. However, before more

definitive conclusions on the effectiveness of the

Keyes technique can be drawn, a more complete

and longitudinal study is required.

Using our data base, we estimated the average

variable cost of producing the Keyes technique

for 190 patients representing over 800 patient

visits. The estimated average variable cost of a

visit in 1979 was between $17.87 and $13.72, depending on whether it was an initial, followup,

or maintenance visit. These average variable

cost figures should be viewed as only rough estimates, and by definition they omit the fixed cost

of production (e. g., rent). By contrast, the reported charges in 1979 for the initial visit and

the maintenance visit for patients being treated

with the Keyes technique averaged $31.63 and

$27.83, respectively. Given the charge data on

visits, our average variable cost figures appear

to be quite reasonable estimates.

The cost effectiveness of the Keyes technique,

if i t does have a long-term effectiveness, depends in part on the amount of periodontal surgery that is avoided. Although we are currently

unable to estimate this amount or to obtain an

estimate from the published literature, the dentists in our study indicated that only between O

and 5 percent of patients being treated with the

Keyes technique also required a referral to a

periodontist. If this estimate is correct and generalizable, then the potential savings of the

Keyes technique are large.

Our assessment of the literature on the effectiveness of periodontal surgery suggests that

further long-term clinical studies are needed.

Such studies would be quite useful if they were

designed to compare the Keyes technique to

periodontal surgery and included a control

group which did not receive either treatment.

The patients under study should be randomly

assigned to each of these three groups. The random assignment of patients into a nontreatment

group raises an important ethical issue. However, our assessment of the current method of

treating periodontal disease raises serious questions about its effectiveness, so the assignment

of patients to a nontreatment group, with their

informed consent, may be feasible. The costs of

each of these alternatives—periodontal surgery,

the Keyes technique, and no treatment—should

be computed and compared.
16 ● Backround Paper #2: Case Studies of Medical Technologies

APPENDIX A.–GLOSSARY OF DENTAL TERMS

Calculus.—Calcium phosphate and carbonate with

organic matter deposited upon the surfaces of the

teeth.

Cementum.—The bonelike connective tissue covering the root of a tooth and assisting in tooth support.

Gingiva. —Gum of the mouth.

Gingivitis.–Inflammation of the gingiva (gum) only.

Keyes technique.—A nonsurgical method of treating

periodontal disease which involves microscopic

determination of the microbial status, the application of certain salt solutions in all instances, periodic courses of systemic antibiotics when indicated, and an extensive regimen of oral hygiene instruction.

Maintenance.—Patient seen periodically for assessment of periodontal health status, cleaning (prophylaxis), microscopic assessment of bacterial activity, and oral hygiene instruction if needed.

Mobile teeth. —Loose teeth.

Mucogingival surgery. —Surgical removal of pockets

involving soft tissue only as part of the surgical approach to treating periodontal disease.

Osseous surgery .—Surgical removal of bone as part

of the surgical approach to treating periodontal

disease.

Quadrant. -A term used for descriptive purposes to

designate any one of four areas of the teeth and

gums (e.g., the upper right quadrant or the lower

left quadrant).

Periodontal disease.—Diseases of the supporting

structures of the teeth (e. g., gingivitis, periodontitis),

Periodontist. —A dental specialist who concentrates

on periodontal disease.

Periodontitis. —Inflammation of the supporting

structures of the teeth including bone, The use of

this term connotes destruction of the periodontal

tissues.

Periodontium. —The tissues investing and supporting

the teeth, including the cementum, periodontal ligament, alveolar bone, and gingiva.

Plaque.—A gummy, almost exclusively bacterial

substance which adheres to the teeth and is discernible only by applying stains, Plaque is the primary causative agent in periodontal disease.

Pocket.—The deepening of the normal space between the gum and the tooth due to inflammation.

Probing.—Placing a dental instrument under the gingiva or gum to determine whether or not bleeding

will occur and to measure periodontal pockets, if

present,

Prophylaxis.—The use by professionals of appropriate procedures and/or techniques to clean the

teeth.

Radiograph.—A film of internal structures of the

mouth produced by X-ray.

Root planing. –Smoothing of the root surfaces of the

teeth using certain instruments.

Scaling.—Removal of calculus material from the

tooth surfaces and that part of the teeth covered by

the marginal gingiva.

Sulcus.—The normal space between the gum and the

tooth,
Case Study #S Periodontal Disease Assessing the Effectiveness and Costs of the Keyes Technique ● 17

APPENDIX B.–QUESTIONNAIRE USED TO COLLECT DATA

Dentist Age Years in Practice

1. Approximate length of time you have been using the Keyes technique:

Years

2 .

5.

6.

7.

For approximately how many patients have you used the Keyes technique?

Patients

Do you use the Keyes technique as a preventive method as well as a treatment

method?

Yes No

Approximately what percentage of the patients with whom you have been using

the Keyes technique also require some form of periodontal surgery?

o-5% 5-lo % 10-20% 20-30%

How much do you refer patients to periodontists now as compared to before

you began to use the Keyes technique?

More Less Same

Considering all of your patients that have been treated by the Keyes

technique, approximately what percentage do you consider to have been

treated :

% Successfully % Unsuccessfully

What do you believe are the principal reasons for lack of success?

(Use the back of this page if necessary.)

8. Would you be willing to allow me to ask the patients on whom you have

completed a questionnaire to answer a few questions about their feelings?

Yes No

9. If yes, please sign your name:
I8 Background Paper #2: Case Studies of Medical Technologies

Patien t Age sex

Address

Date patient began treatment with Keyes technique Today's Date

Total number of visits for the Keyes technique made by patient to date

Total number of maintenance visits to date

At Initial Visit

PERIODONTAL STATUS

(Please check where appropriate)

At This Time

Healthy, on maintenance care only

Gingival inflammation only

Bleeding on probing

Suppuration

Radiographic evidence of bone loss

Number of mobile teeth

Number of quadrants of involvement

Microscopic - many WBC's

Microscopic - many motile forms

ASSESSMENT OF PATIENT’S PLAQUE CONTROL

Above average (doing well on own)

Average (needs some professional instruction)

Below Average (needs a great deal of

professional instruction)

Approximate total number of hours of plaque control instruction given

By whom: Dentist

Hygienist

Dental Assistant

Frequency of prophylaxis times per year

USE OF ANTIBIOTICS TO TREAT THE PATIENT

Yes No

If yes, how long was each course? -weeks. How many courses?

PATIENT USES:

(please check correct response)

Baking soda and peroxide

Fluorid e

Irrigatio n

Other, please indicat e

Yes No

Yes No

Yes No

Yes No
Case Study #5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 19

Has this patient been treated prior to seeing you?

Yes— No—

for periodontal disease

If yes, was it by a general dentist or a periodontist ?

PLEASE CHECK WHICH PROCEDURES ARE DONE AT EACH VISIT FOR THIS PATIENT

USING THE KEYES TECHNIQUE

VISITS

1st 2nd 3rd 4th 5th 6th Maintenance

Dental history

Medical history

Radiographs

Visual assessment

Periodontal probing

Pocket measurement

Microscopic examination

Scaling

Root planing

Plaque control instruction

Other (list )

Other (list )

PLEASE ANSWER THE FOLLOWING FOR THIS PATIENT USING THE KEYES TECHNIQUE

1. Average chair time per

patient visit (minutes)

2. How many minutes

time was with:

Dentist

Hygienist

of this

Dental Assistant

Other (specify)

3. Approximate cost to

patient per visit

$ — $ — $ — $ — $ — $— —$

4. If cost was on the basis of a total case, what was the cost per case? $

5. What was the average charge to patient for maintenance visit? $

COMMENTS

If you feel that these questions will not show the correct information about

either effectiveness or cost using the Keyes technique for this patient, please

supply the information you believe will help on the back of this page.
20 . Background Paper #2: Case Studies of Medical Technologies

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

“Agents for the Control of Plaque: A Symposium Presented at the Meeting of the International Association for Dental Research, ” J. Dent.

Res. 58:2378, 1979.

American Dental Association, Bureau of Economic Research and Statistics, “Dental Fees

Charged by General Practitioners and Selected

Specialists in the United States, 1977, ” J. Am.

Dent. Assoc., October 1978.

The 1977 Survey of Dental Practice s

(O@&: ADA, 1977) .

Axelson, P., and Lindhe, J., “Effect of Controlled Oral Hygiene Procedures on Caries and

Periodontal Disease in Adults, ” J. Clin. Periodont. 5:133, 1978.

“The Effect of a Preventive Programme

on Dental Plaque, Gingivitis, and Caries in

Schoolchildren: Results After One and Two

Years,” ]. Clin. Periodont. 1:126, 1974.

Chilton, N. W., and Miller, M. F., “Epidemiology of Periodontal Disease: Position Report and

Review of Literature, ” in International Conference on Research in the Biology of Periodontal Disease (Ann Arbor, Mich.: University of

Michigan, 1977).

Cohen, D. W., “Role of Periodontal Surgery,”).

Dent. Res. 50:212, 1971.

Committee Report, in lnternational Conference

on Research in the Biology of Periodontal Disease (Ann Arbor, Mich.: University of Michigan, 1977).

Committee Report: “The Etiology of Periodontal Disease, ” in World Workshop in Periodontics, S. P. Ramfjord, et al. (eds. ) (Ann Arbor,

Mich.: University of Michigan, 1966).

Douglass, C. N., and Day, J. M., “Cost and

Payment of Dental Services in the United

States,” J, Dent. Educ. 43(7) :33o, 1979.

Garrett, J. S., “Root Planing: A Perspective, ” J.

Periodont. 48:553, 1977.

Gibson, R. M., “National Health Expenditures,

1978, ” Health Care Fin. Rev. 1(1), summer 1979.

Henry, J. L., and Sinkford, H. C., “The Economic and Social Impact of Periodontal Disease:

Position Report and Review of Literature, ” in International Conference on Research in the Biology of Periodontal Disease (Ann Arbor, Mich.:

University of Michigan, 1977).

Hurt, W. C., “Periodontal Diagnosis–1977: A

status Report, ” J. Periodont, 48:533, 1977.

Ingle, J. I., “The Health, Economic, and Cultural

Impact of Periodontal Disease on Our Aging

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

Population, ” presented at the National Institutes

of Health Conference on Aging, Louisville, Ky.,

1975.

Kelly, J. E., and VanKirk, L. E., “Periodontal

Disease in Adults: United States 1960-62, ” PHS

publication No. 10 (Washington, D. C.: U.S.

Government Printing Office, 1965).

Keyes, P. H., et al., “The Use of Phase-Contrast

Microscopy and Chemotherapy in the Diagnosis

and Treatment of Periodontal Lesions—An Initial Report (I), ” Quintessence lnternat. 1:5I,

1978.

“The Use of Phase-Contrast Microscopy

and Chemotherapy in the Diagnosis and Treatment of Periodontal Lesions—An Initial Report

(II), Quintessence lnternat. 2:69, 1978.

Lee, H., et al., “Experimental Gingivitis, ” Man.

J. Periodont. 36;177, 1965.

Loesche, W. J., “Chemotherapy of Dental

Plaque Infections, ” Oral Sci. Rev. 9:63, 1976.

Pennel, B. M., and Keagle, J. G., “Predisposing

Factors in the Etiology of Chronic Inflammatory

Periodontal Disease, ” J. Periodont. 48:517,

1977.

Periodontal Disease and Oral Hygiene Among

Children, DHEW publication No. (HSM) 72-

1060 (Washington, D. C.: Department of Health,

Education, and Welfare, 1972).

Ramfjord, S. P., “Surgical Pocket Therapy,”

Int. Dent. J. 27;263, 1977.

Ramfjord, S. P., et al., “Longitudinal Study of

Periodontal Therapy, ” J. Periodont. 44:66,

1973.

Ranney, R. R., “Pathogenesis of Periodontal

Disease: Position Report and Review of Literature, ” in International Conference on Research

in the Biology of Periodontal Disease (Ann Arbor, Mich.: University of Michigan, 1977).

Rosling, B., et al., “The Effect of Systemic

Plaque Control on Bone Regeneration in Infrabony Pockets, ” J. Clin. Periodont, 3:38, 1976.

“The Healing Potential of the Periodontal Tissues Following Different Techniques of

Periodontal Surgery in Plaque-Free Dentitions, ”

J. Clin. Periodont. 36:233, 1976.

Rovin, S., “A Curriculum for Primary Care

Dentistry, ” J.E. D. 41:176, 1977.

Sheiham, A., “Prevention and Control of Periodontal Disease, ” in International Conference

on Research in the Biology of Periodontal Disease (Ann Arbor, Mich,: University of Michigan, 1977).
Case Study #.5 Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 21

30.

31.

32.

Soransky, S. S., “Microbiology of Periodontal

Disease—present Status and Future Considerations, ” J. Periodotlt. 48:497, 1977.

Suomi, J. D., et al., “The Effect of Controlled 33.

Oral Hygiene Procedures on the Progression of

Periodontal Disease in Adults: Results After

Third and Final Year, ” J. Periodont. 42:152,

1971. 34.

Tanzer, J. M., “Microbiology of Periodontal

Disease: Position Report and Review of Literature, ” in International Conference on Research

in the Biology of Periodontal Disease (Ann Arbor, Mich.: University of Michigan, 1977).

U.S. Department of Health, Education, and

Welfare, “Edentulous Persons, United States, ”

National Center for Health Statistics, series 10,

No. 89, 1971.

Zander, H. A., and Poison, A. M., “Present

Status of Occlusion and Occlusal Therapy in

Periodontics, ” J. Periodont. 48:540, 1977.
Commentary

Editor of Commentary:

AlIan J. Formicola, D.D.S.

Dean, School of Dental and Oral Surgery

Columbia University

Authors:

R. Gottsegen, D.D.S.

Professor of Dentistry

Director of Periodontics

School of Dentistry

Columbia University

S. Socransky, D.D.S.

Senior Staff Member

Head of Periodontics

Forsyth Dental Center

J. Hay, Ph. D.

Assistant Professor

School of Dental Medicine

University of Connecticut
Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Diagnosis of Periodontal Disease and Monitoring of Disease Activity . . . . . . . . . . 26

Are the Samples Representative? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Is the Test Diagnostic of Disease Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

The Use of Salt, Hydrogen Peroxide, Sodium Bicarbonate, andTetracycline

as Therapeutic Agents in the Control of Periodontal Disease and the Use

of PhaseMicroscopy as a Patient Motivator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Economic Perspectives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Commentary

Editor of Commentary:

AlIan J. Formicola, D. D.S.*

Dean, School of Dental and Oral Surgery

Columbia University

New York, N.Y.

INTRODUCTION

Periodontal disease is ubiquitous, affecting 80

to 90 percent of the adult population. It may

range from simple gingivitis to advanced destructive periodontitis in which there is destruction of the supporting tissues around the teeth,

resulting in tooth loss.

Treatment of early, or mild, periodontal disease is usually simple, short, and successful.

Treatment of advanced periodontitis, though

more involved and protracted, has a high success rate. Further, treatment is based on the

long-term experience of many expert clinicians

and observers, supported by sound clinical

research.

The criteria for a clinical investigation to be

considered as having scientific merit are the

following: I) the use of reliable and standardized measurements; 2) adequate controls, particularly in clinical trials; 3) presentation of data

in a form allowing appropriate statistical analysis; and a) submission of reports to peer review

*In addition to Dr. Formicola, the primary authors of this commentary are: R. Gottsegen, Professor of Dentistry, Director of

Periodontics, School of Dentistry, Columbia University; S. Socransky, Senior Staff Member, Head of Periodontics, Forsyth

Dental Center; and J. Hay, Assistant Professor, School of Dental

Medicine, University of Connecticut.

The authors gratefully acknowledge the contributions of the

following individuals: John J. Bergquist, Professor and Chairman

of Periodontics, University of Maryland; R. Caffesse, Professor

and Chairman of Periodontics, School of Dentistry, University of

Michigan; D. Fine, Associate Professor of Dentistry, School of

Dentistry, Columbia University; P. Kamen, Assistant Professor of

Dentistry, School of Dentistry, Columbia University; J. Kennedy,

Professor of Dentistry and Dean, School of Dentistry, Virginia

Commonwealth University; A. Poison, Chairman of Periodontics,

Eastman Dental Center, and Associate Professor, University of

Rochester; and R. Rosenberg, Assistant Clinical Professor, School

of Dentistry, Georgetown University.

by publication in scientific journals. Studies not

adhering to these standards are not scientifically

valid, and their results must be considered anecdotal. Scheffler and Rovin’s study of the Keyes

technique in 18 dental practices in the Washington, D. C., area does not adhere to these standards.

However, there is in the scientific literature

abundant well-documented evidence that

plaque removal and subsequent control arrests

or reverses gingivitis and early periodontitis.

Since the Keyes technique relies principally on

plaque removal and control, it is not a new

technique at all, for plaque removal and control

are exactly what all dentists who treat periodontal disease do as the initial and basic part of their

therapy.

For hundreds of years, periodontal treatment

has been based on the removal of hard and soft

deposits from tooth surfaces. This therapy has

been quite effective. However, cases of advanced periodontal disease may require the use

of surgical procedures for the proper debridement of inaccessible microbial masses and calculus. The depths of periodontal pockets or

other difficult to reach places cannot be thoroughly cleansed unless exposed surgically. Indeed, root surfaces with periodontal pockets

deeper than 5 mm may still harbor significant

numbers of micro-organisms despite careful

scaling by skilled operators (12). A further beneficial effect of the surgical approach may be to

reduce pocket depth, thus making formerly inaccessible areas accessible for the patient to exercise plaque control.

25
26 ● Background Paper #2: Case Studies of Medical Technologies

A study of the result of conventional therapy

was reported by Hirschfeld and Wasserman in

1978 (l). This study involved 600 patients, most

of whom had advanced periodontal disease. All

these patients had been referred to a periodontal

specialist for care because they were in imminent danger of losing teeth. All 600 received

conventional periodontal treatment, which for

many included surgery when indicated; and all

then had followup care for 15 to 50 years (with a

mean duration of observation of 22 years).

Eighty-three percent of these patients lost only O

to 3 teeth. The fact that these patients with advanced disease lost so few teeth during that long

time span demonstrates the success of conventional periodontal therapy. However, a small

subgroup of 25 patients (4.2 percent) in this

study lost more than 10 teeth in the 22-year followup period. Recent evidence from other studies suggest that this subgroup of patients probably had a more aggressive or rapidly progressing form of adult periodontitis.

It should be noted that the Hirschfeld and

Wasserman study did not include patients with

simple gingivitis or early periodontitis; the

study examined only the results of conventional

treatment of patients with advanced periodontal

disease. No similar conclusions regarding the effectiveness of the Keyes technique in the treatment of advanced periodontal disease can be

drawn from the study by Scheffler and Rovin

for two reasons. One, the authors provide no

useful information indicating the severity of the

patients’ disease, and two, their study is of such

short duration that it is valueless for judging the

long-term effect of the Keyes technique on advanced periodontal disease.

There are other careful long-term studies

which have demonstrated the long-term success

of conventional treatment: Ramjford, et al. (7),

Knowles, et al. (3), Lindhe and Nyman (4), and

Nyman and Lindhe (6). These studies followed

the patients for periods of time up to 10 years

after treatment. Treatment was careful preparation of the patient by scaling, plus motivation

and training in oral hygiene. Surgery was indicated because of the severity of the patients’

periodontal disease.

All of these studies constitute strong evidence

that conventional periodontal therapy, including surgery and proper maintenance by the dentist and the patient, can stop the progress of advanced periodontal destruction and maintain

the dentition in the majority of cases.

When comparing these well-designed studies

of conventional treatment that have been reported in the scientific literature to the study of

the Keyes technique by Scheffler and Rovin, one

must point out that the Keyes technique involves the same antimicrobial approach as conventional therapy. However, Keyes only rarely

accepts the use of surgery to gain access to more

deeply involved areas. His method is to flush

such areas with salt solutions, which, he states,

is sufficient to kill pathogenic bacteria. Whether

salt solutions actually achieve this goal is not

clear at this time. Thus, it is premature to suggest that this treatment regimen alone should be

used in human patients as a replacement for

techniques that have been documented to control periodontal diseases.

DIAGNOSIS OF PERIODONTAL DISEASE

OF DISEASE ACTIVITY

AND MONITORING

The Keyes technique employs a diagnostic tions: 1) that the microbiologic samples taken

test that has not yet been validated as a measure are representative of the microbiota (bacterial

of disease activity, namely, phase-microscopic population) in the worst-diseased sites, and

examination of wet samples of material scooped 2) that the test is diagnostic of disease activity

out of periodontal pockets. Implicit in reliance and can also be used to monitor the effects of

on this test are at least two unproved assump- treatment.
Case Study #5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 27

Are the Samples Representative?

The basis of choosing the sites for sampling of

subgingival plaque has not been clearly defined

by Keyes, apart from a statement that “particular effort is made to obtain samples from deeper

subgingival spaces that are difficult for the patient to clear (sic)” (2). That the samples are

representative is an unwarranted assumption,

because there is a dramatic variation in the bacterial population from site to site within the

same individual, from supragingival (above the

gum margin) sites to subgingival (below the

gum margin) sites, from diseased sites to healthy

sites, and between sites with different forms of

periodontal disease (5,8,9,10). Therefore, there

is no basis for using a sample of bacteria from

one area as an indication of the bacterial population of the plaque from a patient’s mouth.

Is the Test Diagnostic of

Disease Activity?

Any proposed diagnostic test must be validated. The one used in the Keyes technique has

not been. Keyes’ claim that the state of disease

activity can be determined by examining the

proportion of motile forms on a microscopic

slide is not substantiated by scientific evidence.

Research on the possible existence of such a relationship is just now being invited in a “Request

for Proposals” issued by the National Institutes

of Health (RFP No. NIH-NIDR-81- 3R).

However, there is at this time a limited

amount of established knowledge about the relationship of motile organisms and periodontal

disease. That phase microscopy could be sensitive to all forms of active periodontal destruction is doubtful. For example, in the case of periodontosis, an actively progressive periodontal

disease that causes major destruction of bone

surrounding the teeth in young individuals,

there are few motile organisms even though the

disease is progressing at a rate generally considered to be much faster than that of adult periodontitis. The organism that has been shown to

be uniquely and closely associated with this

condition is not motile.

Thus, it seems clear that to date there is no

convincing rationale for the use of phase microscopy for either of the two uses suggested by

Keyes.

THE USE OF SALT, HYDROGEN PEROXIDE,

SODIUM BICARBONATE, AND TETRACYCLINE AS THERAPEUTIC

AGENTS IN THE CONTROL OF PERIODONTAL DISEASE AND

THE USE OF PHASE MICROSCOPY AS A PATlENT MOTIVATOR

A widespread group of therapeutic modalities

is employed in the Keyes technique. One modality is scaling, which as stated above has been

shown to be effective in controlling periodontal

disease. In addition, Keyes advocates local applications of concentrated salt solutions and/or

pastes of sodium chloride, magnesium chloride,

hydrogen peroxide, and often the systemic administration of tetracycline (an antibiotic) under

certain conditions. At present, tetracycline has

been shown to be needed in only a small number

of cases which responded poorly to routine therapy. The use of this drug in about half of the patients treated by the Keyes followers in Scheffler

and Rovin’s Washington area study is totally

unjustified. Furthermore, no evidence is available which suggests that the local applications

of salt solutions or pastes or hydrogen peroxide

reduce the rate of periodontal destruction, prevent the recurrence of active periodontal lesions

in a treated patient, or add anything to the existing regime of periodontal therapy.

Keyes and followers assert that phase microscopy has value in motivating a patient to perform proper oral hygiene. This assertion is

based on the assumption that patients are more

willing to follow the dentist’s directions to clean

their mouths properly when shown the living

bacteria which can be scraped off their teeth.
28 ● Background Paper #2: Case Studies of Medical Technologies

However, the American Society of Preventive tients, found that the technique does not proDentistry, which in the 1960’s spearheaded an vide a better approach to patient motivation

effort to use phase microscopy to motivate pa- than traditional modes of hygiene instruction.

ECONOMIC PERSPECTIVES

CBAS and CEAS of medical-dental procedures

are essentially accounting procedures carried

out to determine if a given program, or in this

case a treatment regimen, is worth the effort.

These analytic techniques have become increasingly sophisticated in the last 5 years (11,13).

CBA relates the total costs of receiving such

treatment to the total benefits, while CEA compares the costs of one treatment modality to

those of another, or to a group of alternative

treatments, having established that all of the

treatments meet a minimum acceptable level of

effectiveness.

Scheffler and Rovin do not present a complete

picture of costs and benefits nor of the costs of

alternative treatments. Although they discuss

alternative surgical and nonsurgical techniques,

they do not present the types of data necessary

to compare these alternatives with the Keyes

technique.

The only costs that Scheffler and Rovin present are certain average variable labor and

SUMMARY

Researchers can point to mounting evidence

that dentistry is gaining the scientific knowledge

that will provide the public some measures for

the prevention and management of periodontal

disease. Dentistry has repeatedly demonstrated

its willingness to support major public health efforts. Dental researchers and practitioners have

actively participated in the development of the

scientific base, clinical applications, and promotion of measures to control dental caries

through the use of fluoride and, more recently,

sealants. Now the dental research community is

seeking to conquer caries totally by developing

a caries vaccine. Research towards this goal is

being carried out at a number of research

capital

figures

costs of dental office visits. Even these

are inconclusive. The authors’ data are

not clear and do not specify whether all of the

dentists were providing the same mix of dental

services. Their cost estimates might differ considerably if periodontists or general practitioners proficient in periodontal surgery were

included in the data sample.

A more glaring deficiency, which the authors

have acknowledged by disclaimer, is the lack of

any estimates of patient opportunity costs, both

in the dental office visits and in home oral

hygiene. Generally speaking, patient opportunity costs would capture the value of resources

consumed by the patient in addition to dental

office charges. These costs would include transportation costs to visit the dentist, time spent in

home oral hygiene, etc. They would also include

dentist opportunity costs, e.g., the cost of training personnel to carry out the Keyes regimen.

centers, supported cooperatively by universities

and the National Institutes of Health.

While our scientific knowledge base for periodontal disease may lag behind that for caries,

significant advances have been made in the last

decade and a half by a diverse and dedicated

group of scientists and concerned clinicians.

We understand and sympathize with the goal

of Dr. Keyes and coworkers as well as Drs.

Scheffler and Rovin to provide better, simpler

and less expensive therapy to all periodontal patients, because this is a goal shared by all individuals in periodontal research. However, the

standard for acceptance of therapy cannot
Case Study #5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 29

become enthusiastic advocacy, popular appeal,

and press releases, but must be carefully controlled clinical and laboratory testing. AcceptREFERENCES

1,

2.

3.

4.

5.

6.

Hirschfeld, L., and Wasserman, D., “A LongTerm Survey of Tooth Loss in 600 Treated Periodontal Patients, ” J. Periodont. 49:225, 1978.

Keyes, P. H., et al., “The Use of Phase-Contrast

Microscopy and Chemotherapy in the Diagnosis

and Treatment of Periodontal Lesions—An Initial Report (I), ” Quintessence Internat. 1:51,

1978.

Knowles, J. W., et al., “Results of Periodontal

Treatment Related to Pocket Depth and Attachment Level: Eight Years, ” J. Periodont. 50:225,

1979.

Lindhe, J., and Nyman, S., “The Effect of

Plaque Control and Surgical Pocket Elimination

on the Establishment and Maintenance of Periodontal Health: A Longitudinal Study of Periodontal Therapy in Cases of Advanced Periodontitis, ” J. Clin, Periodont. 2:67, 1975.

Listgarten, M. A., and Hellden, L., “Relative

Distribution of Bacteria at Clinically Healthy

and Periodontally Diseased Sites in Humans, ” J.

Clin. Periodont. 5:115, 1978,

Nyman, S., and Lindhe, J., “A Longitudinal

Study of Combined Periodontal and Prosthetic

Treatment of Patients With Advanced Periodontal Disease,” J. Periodont, 50:163, 1979.

ance of the former as standards would be as a

sharp step backward for the dental profession

and for the public.

7.

8.

9.

10,

11.

12.

13.

Ramfjord, S. P., et al., “Longitudinal Study of

Periodontal Therapy, ” J. Periodont. 44:66,

1973.

Slots, J., “Subgingival Microflora and Periodontal Disease, ” J, Clin. Periodont. 6:351, 1979.

Socransky, S. S., “Microbiology of Periodontal

Disease—Present Status and Future Considerations, ” J. Periodont, 48:497, 1977.

Syed, S. A., and Loesche, W. J., “Bacteriology

of Human Experimental Gingivitis: Effect of

Plaque Age, ” Infect. and Immun. 21:821, 1978.

Thompson, M., Benefit-Cost Analysis for Program Evaluation (Beverly Hills, Calif.: Sage

Press, 1980).

Waerhaug, J., “Healing of the Dento-Epithelial

Junction Following Subgingival Plaque Control,

II: As Observed on Extracted Teeth, ” J. Periodent. 49:119, 1978.

Warner, K., and Luce, B., Cost-Benefit and

Cost-Effectiveness Analysis in Health Care:

Principles, Practice and Potential (Ann Arbor,

Mich.: Health Administration Press, in press,

1981).
AUTHORS’ RESPONSE TO COMMENTARY

In his commentary, Dr. Formicola includes

among the criteria for evaluating a scientific

clinical investigation the use of adequate control

groups, and he further states that studies without such controls must be considered “anecdotal. ” A control group in a clinical study is

generally defined as a group of patients which is

comparable to the treatment group but which

does not receive the therapy that is to be

studied. However, the clinical studies of periodontal therapy that Dr. Formicola cites do not

use control groups; instead, they report the impact of the application of one therapeutic modality or another. Thus, according to Dr.

Formicola’s commentary, these studies should

be labeled “anecdotal. ”

Actually, the lack of control groups is a fundamental problem found in most of the literature on periodontal disease. Specifically, there

have been few controlled clinical studies in

which a treatment group received periodontal

procedures and a control group received no

therapy at all. The one major study that did use

a control group (4) dealt with the use of oral

hygiene procedures only; it did not include surgical procedures. That investigation was cited in

our case study, but not in Dr. Formicola’s commentary.

There are no scientific studies which show

that the surgical approach to treating periodontal disease is any better than the conservative

approach used by clinicians for many years. Actually, a major recommendation in our case

study is that such controlled clinical studies be

carried out: “Our assessment of the literature on

the effectiveness of periodontal surgery suggests

that further long-term clinical studies are

needed. Such studies would be quite useful if

they were designed to compare the Keyes technique to periodontal surgery and included a

control group which did not receive either treatment .“

In his commentary, Dr. Formicola spoke at

great length about the Hirschfeld and Wasserman study (1) and suggested that it was an example of research with scientific merit. However, it should be noted that in this study, patient samples were not randomized nor selected

30

on any statistical basis; there were no control

groups; and the same dentists who performed

the treatment also evaluated it. The Hirschfeld

and Wasserman study was a retrospective analysis of treatment and was not predicated on a

predetermined treatment modality. Moreover,

there was no rating reliability between the evaluators. In fact, some of the patients were treated

by different dentists at different points in time.

Finally, no statistical tests were used to analyze

the data.

However, even if we ignore these limitations,

the evidence in the Hirschfeld and Wasserman

study (1) points more to the retention of teeth

without periodontal surgery than it does to

retention with surgery. Of the 600 patients in

the study, only 230 (39.3 percent) had periodontal surgery in the first place. According to

Hirschfeld and Wasserman, most of the patients

responded just as well without surgery as with

it: “. . . in the great majority of cases surveyed,

simple but thorough treatment in the form of

subgingival scaling, occlusal adjustment, and

fair to good home care seemed to reduce tooth

loss.” The investigators concluded: “The mortality of teeth which were treated with periodontal surgery was compared with that of teeth

which did not have surgery. Tooth retention

seemed more closely related to the case type

than the surgery performed. ”

Although Dr. Formicola implies otherwise,

the Hirschfeld and Wasserman study cannot be

considered anything other than what he terms

“anecdotal, ” for the reasons we have cited.

Hirschfeld and Wasserman appropriately entitle

their study a survey, “A Long-Term Survey of

Tooth Loss in 600 Treated Periodontal Patients. ” This label is not to denigrate their effort

because the effort did provide useful and important information.

Many of the other clinical studies cited by Dr.

Formicola are deficient because dentists who

performed the surgical therapy also evaluated

the results; independent evaluations were usually absent. The Ramfjord group of studies (3)

had some standardization in that the same evaluators were used throughout, but even in these

studies, it is not clear in some cases whether the
dentists who performed the evaluation did not

also perform the surgery. An even more serious

deficiency is the absence of a control group.

Thus, none of the clinical studies which were

cited by Dr. Formicola conforms to his own criteria for scientific merit. Unfortunately, the clinical studies which occupy the bulk of the periodontal literature lack scientific rigor. But these

are the studies on which periodontal therapy is

predicated. To repeat, the need for randomized

controlled clinical studies of alternative treatments for periodontal disease is essential, so

that effective periodontal treatments can be

identified.

We find it disappointing that Dr. Formicola

believes that cost-benefit analysis (CBA) and

cost-effectiveness analysis (CEA) are “essentially accounting procedures, ” despite the effort

that OTA has made in explaining these concepts. According to OTA: “The terms CEA and

CBA refer to formal analytical techniques for

comparing the positive and negative consequences of alternative ways to allocate resources” (2), OTA found no consensus among

analysts and practitioners as to a standard set of

methods for CEA/CBA (2). Accounting procedures have little, if anything, to do with the analytical technique of CEA or CBA.

We conducted a CEA of the Keyes technique,

but because there was no existing CEA of periodontal surgery, we could not compare the Keyes

technique to the surgical alternative. We did

find national data which show that surgery is

much more expensive than the Keyes technique.

Surgery on a single quadrant of the mouth costs

the patient an average of at least $250, whereas

six visits for the Keyes program cost about $150.

Thus, even without including the cost of followup treatments after surgery, the cost to the patient is considerably higher when surgery is performed than when the Keyes technique is used.

As Dr. Formicola points out, the costs of the

Keyes technique would be different if periodontists performed it instead of general practice

dentists. However, we see no reason to use the

higher wages of periodontists in our calculations

if general practice dentists can deliver the Keyes

technique.
32 ● Background Paper #2: Case Studies of Medical Technologies

warrant a long-term comprehensive investigation. If the Keyes program should prove effective in the long run, it could reduce the cost of

controlling periodontal disease and perhaps

REFERENCES ●

1.

2.

Hirschfeld, L., and Wasserman, D., “A LongTerm Survey of Tooth Loss in 600 Treated Periodontal Patients,” ]. Periodorzt. 49:225, 1978.

Office of Technology Assessment, U.S. Congress,

The Implications of Cost-Effectiveness Analysis

of Medical Technology, GPO stock No. 052-

003-00765-7 (Washington, D. C.: U.S. Government Printing Office, August 1980).

allow the treatment of many more patients with

periodontal disease, as well as reduce the

amount of periodontal surgery and its costs.

3.

4.

Ramfjord, S. P., et al.,

Periodontal Therapy,” ].

“Longitudinal Study of

Periodont. 44:66, 1973.

Suomi, J. D., et ;j., “The Effect of Controlled

Oral Hygiene Procedures on the Progression of

Periodontal Disease in Adults: Results After

Third and Final Year,” ]. Periodont. 42:152, 1971.

* U S GOVERNMENT PRINTING OFFICE 1981 341 -844/1007