Formulating Clinical Practice Guidelines for Magnetic Attachment
Applications – Process and results of the survey with Delphi method –M.Hideshima, T.Ichikawa, H.Koshino, K.Hoshiai, J.Tanaka, S.Ozawa, Y.Suzuki, Y.Umekawa,
T.Ishigami, K.Nagao*, M.Sone*, M.Kono*, J.Wada*, J.Wadachi*，A.Nishiyama*
Dental Care Council and Special Committee* for the Japanese Society of Magnetic Applicationsin Dentistry

In the era of evidence-based medicine, clinical practice guidelines (CPG) have become an integral
task of each academic society, and council for the dental care of this society also performed aquestionnaire survey preparing for CPG for the magnetic attachments. And a total of 147 clinicalquestions (CQs) were returned and divided into 5 categories according to their applications. Eachcategory was dealing with implants, with type of defect, with occlusion and periodontics, witharrangement and configuration and with management or others. And 14 typical CQs for CPGs wereselected. The committee asked each prosthodontic department of several university for each CQ toconduct a literature search and write thorough systematic reviews. However relating literatures foreach CQ lacked and formulating CPG according to the GRADE group system was quite
complicated. Therefore the committee asked 71 clinical experts named “consensus group” to reply
the same questionnaire at 2 times presenting the former results and analyzed the effect for eachoutcome according to Delphi method.

ObjectiveThe objective of this survey was to analyze opinions of clinical experts of MAs and to develop a
consensus of opinion for CQs in the absence of evidence providing guidance on topics that have notstudied in RCT.

Materials and Methods
Council for the dental care of this society performed a questionnaire survey preparing for CPG for
the magnetic attachments. And total of 147 clinical questions (CQs) were divided into 5 categories
according to their applications and 14 typical CQs shown below were selected.
1) Implant(1) In case of implant-supported overlay dentures, are magnetic attachments (MAs) more effective
than other types of retainers?
(2) In case of implant-supported overlay dentures, is the application of MAs to implant abutments
superior to applying them to natural teeth?
(3) When applying magnetic MAs to implant-supported overlay dentures, are maxillary
applications superior to than mandibular ones?
(4) When applying magnetic MAs to implant-supported overlay dentures, are multiple abutmentswith MAs more effective than single abutments?
2) Defects(5) In cases in which individuals have few mandibular teeth, is the application of MAs moreeffective than the use of other types of retainers?
(6) In cases involving removable partial dentures with a free-end saddle, is the application of MAs
more effective than the use of other types of retainers?
(7) In cases involving overlay dentures, is the application of MAs more effective than the use ofother types of retainers?
3) Occlusion/Periodontics(8) In case of partially edentulous patients without occlusal contact, are MAs superior to other typeof retainers?
(9) In cases of partially edentulous with undulating occlusal planes, is the application of MAs
more effective than the use of other types of retainers?
(10) When periodontal disease is affecting remaining abutments, is the application of MAs
superior to the use of other types of retainers?
4) Arrangement / Form
(11) When applying MAs to multiple abutment teeth, are symmetrical arrangements more effective
than asymmetrical ones?
(12) When applying MAs to remaining abutment teeth, are flat type keepers more effective thandome-shaped keepers for stability of the denture?
5) Management/etc.
(13) When undergoing MRI examinations, are there more artifacts in the images with MAs thanthere are in those with other types of retainers?
(14) When applying MAs to removable partial dentures, is the applied pressure method superior tominimum pressure ones?
The committee asked each prosthodontic department of several university in which staff belong to
JSMAD for each CQ to conduct literature searches and summarize systematic reviews. Howevercorresponding literatures or high-quality clinical data for each CQ were limited in number or nothing.
Therefore the committee selected 71 clinical experts of MAs named “consensus group” from 36
members and 35 non-members of JSMAD and asked them to reply the questionnaire according toDelphi method in order to achieve consensus of clinical opinions.
Ten CQs in the absence of evidence from 14 CQs above were selected for the Delphi
questionnaire. The questionnaire was framed with 11 outcomes which were affected or not affectedby applying MAs in each CQ (Table 5). The degree of effects on each outcome was selected to markwith rating scale from -5 to +5.
The first questionnaire (round 1) contained questions regarding the clinical experience of MA andimplant of the experts (Table 1-4).
The committee sent the similar questionnaire at 2 times and in the second questionnaire thecommittee provided anonymous statistical summaries at the round 1so that responders can comparewith their own opinion (Table 5).

Results
Thirty eight experts of consensus group replied to the questionnaire regarding 11 outcomes in 10CQs.
The tables below show the clinical experience of the experts (consensus group).

Clinical experience of the consensus groupYears ofclinical
experience

Number of
persons

10y～34

5～10y

3

2～5y

1～2y0

Table 1: Participants classified by years ofclinical experience (N=38)

Number of
MA cases

Number of
persons

10～35

5～92

1～41

None0

Table 2: Participants classified bynumber of cases of MA (N=38)
Number ofMA cases inimplant

Number of
persons

10～135～94

21～4710None

14Years of clinicalexperience ofimplant cases

Number of
persons

10y～

17

5～10y

9～5y
None

Table 3: Participants classified by years of clinicalexperience of implant cases (N=38)

Table 4: Participants classified by number ofcases of MA applied to implant (N=38)

Results of the Delphi method
The results of this 2 rounds survey showed convergence to non-effective (0) or bimodal
distributions.
The tables below show the result of CQ. The upper value of each column shows rating scalefrom -5 to +5 and the lower value of each column shows distribution of numbers of experts. Redbold value shows the results of round2 different from those of round1. 【CQ6：In cases involving removable partial dentures with a free-end saddle, is the applicationof MAs more effective than the use of other types of retainers?】
・Please select the number below according to the effect on each outcome when you apply MAs
on removable partial dentures with a free-end saddle.

(Supposing the case was in maxillaryKennedy classⅠand abutments were bi-lateral premolars or canines .)← opposite effective
1. Effective for the retentive force of denture retainers

effective →non-effective-5-4-3-2-1

0

12

3

4

5000

1

0

40

3

21

6

3-5-4-3-2

-1

0

12

3

4

50

0

0

0

0

170

2

10

5

4-5-4-3-2

-1

0

1

2

3

4

50

0

0

0

0

21

0

1

10

3

3-5-4-3-2

-1

0

12

3

4

50

0

0

0

0

70

2

3

10

16-5-4-3-2-101234

50

000011220

86-5-4-3-2-1

0123

4

5002

10

6022043

7. Effective for durability (longevity of abutments or dentures,-5-4-3-2

-1

0

12

3

4

5

against periodontal disease/dental caries)
8. Effective in maintaining sound periodontal tissue

00000

19

1

3

102

3-5-4-3-2

-1

0

12

3

4

500

100

17

1

9334

9. Affect on imposition (physical and time consuming-5-4-3-2-1012345strain on patients or doctors)
10. Affect on harm(damage from tooth reduction or pain)

1113026

1

1400-5-4-3-2-10123451

14002710

400-5-4-3-2-10123456

1

4

40210

1

100

2. Effective for masticatory function
3. Effective for pronunciation
4. Effective for esthetics
5. Effective for comfort (wearing sensation or discomfort)
6. Effective for adaptability (management or repair)

11. Effective in reducing the cost(Upper value: rating scale, lower value: number of persons, red bold; round2 results different from round1 )Discussion
Most of the prosthodontic issues including MAs do not yield to randomized clinical trials or to
stepwise quantitative data analysis. In such cases, experts use their training and personal anecdotal
experience to assist decision making in a variety of practice contexts. In these circumstances,consensus opinion of experts provides a formal structured process for decision support.
The Delphi method provides anonymity to study participants and has been found to produce more
frequent and stable consensus than other methods. Delphi is described as a structured group
communication process that allows a clinical decision-making group to resolve complex problems
with the goal of producing useful guidance and opinions for decision makers. Delphi technique
refines expert opinion data through consideration of anonymous input from other peer experts,generating a considered consensus over repeated applications.
And an open-ended survey should be sent to experts who in turn provide responses that allow theDelphi experimenter to frame items for subsequent surveys. In this survey some experts mentioned
indistinct clinical situations on each CQ of MAs at the first round. Therefore detailed clinicalsituations were added to each CQ at the second round so that responders could suppose similar cases
to lead convergence of opinion towards consensus.
The results of this survey tended to converge to non-effective (0) in each outcome which showed
diverged distribution at the first round. Also the distribution of the second round tended to converge
to a certain value comparing to the first round which represent more effective or opposite effective.

Conclusion
・A total of 14 typical CQs; Implant, 4; Defects, 3; Occlusion/ Periodontics, 3; Arrange/Form, 2;Manage/etc., 2 were selected.
・Delphi questionnaire survey was performed to 71 experts for 10 CQs in the absence of evidence.
・Eleven outcomes which were affected by MAs in each CQ were selected and were evaluated withrating scale from -5 to +5.
・Thirty eight experts replied and more than 10 had no clinical experience of applying MAs toimplants.
・The distribution of the effect by MAs on each outcome tended to converge at the second survey.

Acknowledgements
Members of the council are grateful to the participants for their cooperation with this study andhopeful that they will participate in the continuation of this effort.

References
1. Hideshima M: Formulating Clinical Practice Guidelines for Magnetic Attachment Applications(in Japanese). J J Mag Dent 21: 16-21, 2012.
2. M.Hideshima, Y.Igarashi, T.Ichikawa, J.Tanaka, T.Kochi, T.Ishigami, T.Andoh, A.Nishiyama:
Questionnaire Survey for formulating Clinical Practice Guidelines for Magnetic Attachments
Applications - Analysis and Selection of the Clinical Questions (CQ) -. J J Mag Dent 20： 5-10,
2011.
3. Hideshima M, Igarashi Y, Ichikawa T, Tanaka J, Kochi T, Ishigami T, Andoh T, Nishiyama A:
Preliminary questionnaire survey for formulating clinical practice guidelines for magnetic
attachments applications. - Analysis and Selection of the Clinical Questions (CQ) -, J J Mag
Dent 19: 29-34, 2010.
4. Iacono V J, Cochran D L: State of the science on implant dentistry: A workshop developed using
an evidence-based approach. Int J Oral Maxillofac Implant 22: 7-10, 2007.
5. Cramer C, Klasser G, Epstein J, Sheps S: The Delphi Process in Dental Research. J Evid BaseDent Pract 8. 211–220. 2008.