bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTIVE RATES OF ASSISTANCE FOR NORWEGIAN INDUSTRIES
Authors: Holmørn Erling , Hægeland Torbjørn
Published: March 2005

We measure the effective assistance to 24 Norwegian private industries in 1989 and 1991 from government budgetary subsidies, indirect commodity taxes, import protection through nominal tariffs and non‐tariff barriers, and electricity market distortions. The assistance effects are measured by the change in the net‐of‐tax value added price due to a removal of the policy measures considered. Most industries were effectively assisted, but the effective assistance differs widely between industries, indicating the overall distortive effect on the industry structure. Agriculture, Food Processing and Manufacture of Beverages and Tobacco stand out as the most assisted industries. Budgetary subsidies and non‐tariff barriers had the strongest effective assistance effect.
THE WEALTH EFFECTS OF INCOME INSURANCE
Authors: Bird Edward J. , Hagstrom Paul A.
Published: March 2005

Precautionary savings models suggest that wealth should rise with income risk. Risk is reduced by means‐tested transfers, however, which implies that transfer programs should discourage private wealth accumulation. We offer a comprehensive empirical assessment based on variation across states in the generosity of a number of programs, specifically unemployment insurance and means‐tested transfers (Aid to Families with Dependent Children and Food Stamps). We use monthly data on married couples from the Survey of Income and Program Participation (SIPP) to regress wealth on income, income risk, and various measures of transfer generosity. The results support the precaution‐ary savings model and reveal moderate negative wealth effects of both unemployment insurance and means‐tested transfers, with an elasticity of about −0.18.
EQUIVALENCE SCALES AND THE WELFARE OF CHILDREN: A COMMENT ON “IS THERE BIAS IN THE ECONOMIC LITERATURE ON EQUIVALENCE SCALES?”
Authors: Bojer Hilde , Nelson Julie A.
Published: March 2005

In a recent issue of this journal, M. Luisa Ferriera, Reuben C. Buse, and Jan‐Paul Chavas argue that the equivalence scales implicit in the official U.S. poverty line and in public welfare programs overcompensate parents for their children, with resulting negative distributional and incentive effects. We show that their analysis is based on a very particular, and ethically unappealing, assumption about the importance of children's well‐being.
ACCOUNTING FOR RESOURCE DEPLETION: A MICROECONOMIC APPROACH
Authors: Cairns Robert D.
Published: March 2005

The theoretical basis of a practical method of accounting for depletion of mineral resources is presented. Rent rises at the rate of interest, but depletion does not. Rent is equal to the sum of depletion and depreciation less any opportunity cost of present production as compared to waiting. Depletion follows a path which is dependent on the depreciation formula chosen by the accountant. The approach is compared to the methods proposed by the BEA in 1994.
REINVESTED EARNINGS IN THE NATIONAL ACCOUNTS
Authors: Dalgaard Esben , Eff Christoffer , Thomsen Annette
Published: March 2005

The paper raises three questions. Firstly, is it warranted that a significant part of primary (property) income is not shown in the national accounts as being distributed to the owners of the assets to which it accrues but ends up as capital gains in the revaluation account? Secondly, why has the SNA chosen not to record reinvested earnings of corporations as flows of property income with the exception of foreign direct investment, and thirdly why the asymmetrical recording of stock investments constituting more than 10 percent of equity capital depending on whether domestic or foreign transactions are concerned? Reinvested earnings on domestic equity investment above 10 percent of a corporation are not recorded as property income in the system.

The paper looks at these three questions from the perspective of the analytical uses of national accounts. The consequences for the analysis of income distribution both between nations and within nations are examined.
Retention for a Removable Partial Denture
Authors: Johnson Dean L.
Published: March 2005

This article addresses the complex nature of retention in a removable partial denture. Retentive features range from magnets and springs to clips, clasps, and interfacial surface tension. The retentive quality of an extracoronal clasp varies with the alloy, physical form, location on the abutment, and positional relationship to other elements. Surveying to identify both occlusogingival and mesiodistal undercuts when the path of random dislodging forces are not definitely controlled is needed for effective retention. Augmentation of ineffective retention in existing clasps should concentrate on methods of deepening the undercut or increasing the suprabulge. Tightening of clasps already in contact with a tooth frequently produces adverse changes.
Rates of Osseointegration of Dental Implants With Regard to Anatomical Location
Authors: Drago Carl J.
Published: March 2005

Purpose Implantation of commercially pure titanium dental implants can be obtained predictably and consistently. The initial research focused on the edentulous population, with most of the fixtures being placed into the anterior mandibular area. There has been increased use of dental implants for partially edentulous patients.

Materials and Methods This study reports the results of 169 consecutively treated patients with 673 fixtures. Patients were observed for 7 months to 8 years following occlusal loading.

Results Implant osseointegration was 89.1% in the anterior maxillae; 71.4% in the posterior maxillae; 96.7% in the anterior mandible; and 98.7% in the posterior mandible.

Conclusions Osseointegration may be most dependent on anatomical location in the jaws.
Compatibility of Type IV Dental Stones With Polysulfide Impression Materials
Authors: Schelb Ernst , Jones John D. , Prihoda Thomas J.
Published: March 2005

Purpose In the American National Standards Institute/American Dental Association specification no. 19, compatibility of impression materials with dental stones is assessed by the presence of a 20μm‐wide line reproduced on an unmodified calcium sulfate dihydrate cast. In actual dental practice, modified type IV dental stones are used, although little is known of their compatibility with polysulfide impression materials. This study evaluated the compatibility of 6 polysulfide impression materials and 11 modified type IV dental stones.

Materials and Methods A line 20 μm wide was etched on four glass dies. Four samples of each combination of impression material and dental stone were prepared according to the manufacturer's directions with an additional 3 minutes for the final setting time. Compatibility was determined by the presence of the reproduced line on the dental stones, as observed under low angle 10 × magnification by four rater groups.

Results The line was reproduced on all of the impression specimens, and the examiners recorded 66 positive identifications of the line on the stone casts out of a possible 1,056 ratings for a total of 6.25% of the specimens. Out of a possible 66 impression‐stone combinations, only 18 reproduced the 20‐μm line. The combinations reproducing the lines most frequently (75%) were Neoplex with Blue Die Stone (Columbus Dental, St Louis, MO) and Coeflex with Indic Die Stone (Coe Lab Inc, Chicago, IL).

Conclusions The study showed that many combinations of polysulfide impression materials and modified type IV dental stones did not reproduce the 20‐μm line; therefore, not every polysulfide is compatible with every type IV dental stone.
The Dental Curriculum: Is It Relevant to Dental Practice?
Authors: Welker William A.
Published: March 2005

Does the undergraduate dental curriculum devote the appropriate amount of time to those areas of dentistry that are relevant to today's general dental practice? In a survey of dentists who graduated between 1980 and 1985, it was determined that they felt curriculum offerings in orthodontics, research, endodontics, periodontics, oral surgery, fixed prosthodontics, and occlusion had not been extensive enough. However, graduates also reported that their educational experiences in biochemistry, dental laboratory procedures, gross anatomy, microbiology, and occlusion were too extensive.
The Reporting of Statistical Inferences in Selected Prosthodontic Journals
Authors: Prihoda Thomas J. , Schelb Ernst , Jones John D.
Published: March 2005

Dental periodicals are the fundamental source of prosthodontic research. The ability to understand and contribute to dental literature is basic to the prosthodontic profession. The purpose of this study is to tally relative frequency with which various descriptive (n = 18), graphical (n = 7), and inferential statistical procedures (n = 68) are used in the prosthodontic literature. Our method consists of four procedures: journal selection, choice of 1987 through 1988 articles with inferential statistical content, tally of the statistical procedures in those articles, and quality control procedures used in obtaining these data. At least 50% of 10 prosthodontists selected 17 of 100 journals most likely to be read by prosthodontists. In the 17 journals, 1,320 articles were screened of which 406 were selected and evaluated for their statistical procedures. The bar and line plots were the most common graphical procedures occurring in over one fourth of the 406 articles. Percentages, means, and standard deviations occurred in more than 40%. Although 58% used the .05 significance level, only 0.3% mentioned power. Analysis of variance was used more often than the t tests (42%v 29%), whereas correlation/regression (21%) and chi‐square tests (14%) were used less often. The t tests, analysis of variance (Duncan, Tukey, and Student‐Newman‐Keuls multiple comparison procedures), chi‐square tests, correlation and regression, and the Wilcoxon tests occurred in at least 5% of the 406 articles.
Comparison of Anterior Tooth Width in Natural and Artificial Dentitions
Authors: Baer Marvin L. , Reynolds Mark A.
Published: March 2005

Purpose This study characterizes the distribution of the mesiodistal widths of maxillary anterior natural teeth for comparison with the widths of the most commonly used artificial denture teeth.

Materials and Methods The width of the six maxillary anterior teeth was measured on a curve defined by the facial surfaces of the teeth. Four hundred fifty‐one casts of completed orthodontic patients (154 men and 297 women) were measured separately by gender. The width of the maxillary anterior natural teeth was compared to that of artificial denture teeth (Bioblend, Dentsply International, York, PA).

Results The mean ± standard deviation (SD) width of the six anterior teeth for men and women (55.6 ± 3.1 mm and 53.6 ± 3.0 mm, respectively) differed significantly (P < .05). The mode (most frequent size) was 55 mm for both men and women; however, 40% of the women and 67% of men had anterior teeth that measured 55 mm or wider. In contrast, the mean width of the most widely distributed artificial maxillary denture teeth (Bioblend) is 50.1 mm, with a range of 44 to 58 mm. Of the 42 molds available, only 5 have a width of 55 mm or greater.

Conclusions These findings suggest that one reason for the inappropriate selection of comparatively small maxillary denture teeth is the lack of physiologically sized tooth molds.
A Method for Occlusal Reshaping
Authors: Fox Clifford W. , Doukoudakis Asterios , Fox Steven W. , Abrams Bernard L.
Published: March 2005

A method for occlusal reshaping is described using a step‐by‐step analysis starting from the articulation of models to the completion of the clinical procedures. Several newly introduced definitions are provided to help the reader understand the procedures. This article is divided into three parts: (1) the preliminary procedures, (2) the occlusal reshaping of the study casts, and (3) the clinical occlusal reshaping. The advantages of this particular method include establishment of anterior guidance before initiating posterior reshaping procedures, maintenance of maximum cusp height and fossae depth, the placement of forces along the mid vertical axis of the teeth, and the establishment of simultaneous even contact of the posterior teeth, while providing the desirable anterior guidance.
Qualitative and Quantitative Guides to the Selection and Arrangement of the Maxillary Anterior Teeth
Authors: Hock Douglas A.
Published: March 2005

A literature review of the selection of the maxillary anterior teeth is presented. Although several different qualitative guidelines are cited, the best method for the selection of the maxillary anterior teeth is the use of pre‐extraction records or old photographs. Numerous qualitative and quantitative guidelines are cited in the literature for the proper placement of the maxillary anterior teeth. Through careful and proper construction of the maxillary wax occlusal rim, these factors may be recorded and relayed to the dental laboratory technician.
The Use of Injectable Polyvinylsiloxane as Medium for Border–Molding Denture Impressions
Authors: Troendle G. Roger , Troendle Karen B.
Published: March 2005

This article describes a technique for making a denture impression using polyvinylsiloxane material to border‐mold a custom tray. This material is more acceptable to both dentist and patient because it is not as messy or time‐consuming as modeling compound. The disadvantage is the initial cost of the materials.
Cyclic Fatigue Testing of Six Endodontic Post Systems
Authors: Cohen Brett I. , Deutsch Allan S. , Musikant Barry Lee
Published: March 2005

Purpose This study tested the comparative cyclic fatigue of six prefabricated post systems (Flexi‐Post (Essential Dental Systems, South Hackensack, NJ), Flexi‐Anterior (Essential Dental Systems), Vlock (Brasseler USA, Inc, Savannah, GA), Parapost (Whaledent/Coltenen, New York, NY), Cytco (L.D. Caulk, Milford, DE), and Access post (Essential Dental Systems).

Materials and Methods Cyclic fatigue testing was obtained with an in vitro fatigue machine that simulated clinical fatigue conditions. An instantaneous applied force of 5.0 pounds was applied to each post specimen and data was recorded when post breakages occurred. If no breakages occurred, then the test was stopped after 2,000,000 repetitions.

Results Failures only occurred with the Cytco and Vlock post designs. The Flexi‐Post, Flexi‐Anterior, Parapost and the Access post all had greater resistance to cyclic fatigue with no failures.

Conclusions This experimental design may simulate biting forces and stresses seen for posts in a clinical situation.
Passive Fit of Implant‐Retained Prosthetic Superstructures Improved by Electric Discharge Machining
Authors: Linehan Allan D. , Windeler A. Stewart
Published: March 2005

Purpose

An absolutely passive fit at the interface with the superstructure and the abutment cylinders is needed for implant longevity. In this study, a method of cast framework correction using electric discharge machining (EDM) was evaluated.

Materials and Methods

An original research model incorporating strain gages was devised to measure the fit of implant superstructures in three dimensions as cast and to compare this relationship with the fit following framework machining with EDM.

Results

Visually, the fit of the frameworks was excellent, and the results of ANOVA demonstrated that the mean fit of the frameworks significantly improved (P > .04) after machining with EDM.

Conclusions

The EDM process offers a rapid, accurate, and simple technique to correct for casting inaccuracies in the fabrication of hybrid implant prostheses.
Evolution of Removable Partial Denture Design
Authors: Becker Curtis M. , Kaiser David A. , Goldfogel Marvin H.
Published: March 2005

This is a brief overview of the progress of design philosophies of removable partial dentures. It begins in 1711 with the first published description of a removable partial denture prosthesis and continues, with discussion of the most significant discoveries, through 1990.
Development of a Radiopaque, Autopolymerizing Dental Acrylic Resin
Authors: Mattie Patrick A. , Rawls H. Ralph , Cabasso Israel
Published: March 2005

Purpose

Current prosthetic acrylic resins are radiolucent and cannot be imaged using standard radiographic techniques. If accidentally impacted or ingested, delays in localizing or removing the foreign body may be life‐threatening. The purpose of this study was to evaluate the influence of an experimental radiopaque additive, triphenyl bismuth (TPB), on polymethyl methacrylate resins formulated for dental use. We also investigated methods to improve TPB‐containing resin microbeads and optimize processing variables for specimen fabrication in autopolymerizing resin systems.

Materials and Methods

Selfcured samples of experimental resins were prepared containing 0% to 27% TPB and were tested according to American National Standards Institute/American Dental Association and International Organization for Standardization performance standards. A control group and two commercial provisional crown and bridge resins were used for comparison.

Results

The standard of radiopacity (aluminum radiopacity) is met at TPB levels of 14.5%. The control resin had a greater transverse deflection compared with the TPB‐resin groups, but deflection was within standard limits for all resins. Polishability, color stability, and solubility were unaffected by TPB, whereas sorption decreased, although not significantly, at higher TPB levels. Translucency decreased at 27% TPB, and specimens containing 0% to 20% TPB were transparent. A tendency to entrain air bubbles, because of the hydrophobicity of TPB, resulted in increased susceptibility to brittle failure at the higher TPB levels. Solubility slightly exceeded American Dental Association standards for all TPB‐resins and the control. All other performance standards were acceptable for resins containing 0% to 20% TPB.

Conclusions

At concentrations that provide a diagnostic level of radiopacity, TPB does not significantly alter required performance and processing properties. Thus, TPB is capable of commercially acceptable performance as a radiopacifying additive for dental acrylics.
A Review of Methods Used to Reinforce Polymethyl Methacrylate Resin
Authors: Vallittu Pekka K.
Published: March 2005

Various methods to reinforce acrylic denture base material have been used to repair fractures in complete dentures. Metal wires and plates have been tested as reinforcement of polymethyl methacrylate (PMMA) resin. The contributions of the studies conducted on this biphase composite system are discussed in this review article. The literature has reported that even thin metal wires incorporated into the PMMA matrix increased the transverse strength of the PMMA construction. Metal mesh inserted into PMMA resin had negligible effects on the transverse strength of the restoration. Macroscopic retention of the metal strengtheners to the PMMA had only a minor effect on the strength in contrast to microscopic retention, which showed a more marked effect. Chemical bonding between the PMMA and metal reinforcer enhanced the strength of the prosthesis with some exceptions.
A Study of Anterior Guidance
Authors: Donegan Sara Jean , Knap Florian J.
Published: March 2005

Purpose This study focuses on the curvature and inclination of the lingual surfaces of the maxillary anterior teeth from the transition point on the cingulum to the incisal edge.

Materials and Methods On 32 sets of mounted casts, 768 measurements were made of the curvature of the lingual surfaces utilizing radius gauges. The inclination of the lingual surface relative to the occlusal plane was recorded. The relationship of the incisal edge of the mandibular teeth to the transition point on the cingulum of the maxillary teeth was determined. Centric occlusion contact was noted on each tooth.

Results Significant differences were found between the measured areas of any one tooth and between the types of teeth. The average radius ranged from 20.5 mm on the mesial ridge of the canine to 5.3 mm in the fossa of the central. The average inclination of the lingual surfaces was 46%. In centric occlusion, 97% of the canines and 59% of the centrals and laterals were in contact with the opposing teeth. These contacts occurred 2.8 mm incisal to the transition point. The centrals contacted two opposing teeth (45%), and canines contacted one opposing tooth (53%).

Conclusions The function and curvature of the incisor teeth vary considerably from those of the canines. Overcontouring the lingual surfaces of the maxillary incisors to gain contact is not normal and may be detrimental.
Management of the Clinical Curriculum in Which Students Direct Rather Than Perform the Laboratory Stages of Restorations
Authors: Leary J. Michael , Haganman Chris R. , Holmes David C.
Published: March 2005

At the University of Iowa, senior dental students direct rather than perform laboratory construction of clinical prosthodontic work. This report highlights the fundamentals of a successful curriculum based on this concept. One critical component of the curriculum involves teaching the process of self‐evaluation of laboratory work as well as the evaluation of work received from a commercial laboratory. Instructors teach students how to evaluate a product in the sophomore preclinical curriculum. A computerized evaluation form, developed by the prosthodontic faculty, allows assessment of the students' laboratory work in addition to self‐evaluation. To incorporate patient care into the appraisal process, a modified preclinical evaluation framework is used during the junior clinical clerkship. This expanded framework takes into consideration patient treatment factors such as degree of difficulty, diagnosis and treatment planning, use of infection control, and students' understanding of patients' comprehensive treatment plan. In the senior clinic, the students' ability to direct the construction of a prosthesis is enhanced by the unique diversity of faculty within the Department of Family Dentistry at the University of Iowa. This department unites private practice dentists with academicians and general practitioners with specialists.
Prosthodontic Management of a Combination Transosteal/ Endosteal Implant Reconstruction: A Clinical Report
Authors: Wolfinger Glenn J. , Rogoff Gary S. , Harrison Jeffery A. , Callum Julie Oliverio
Published: March 2005

This is a clinical report of a patient who was not referred for prosthodontic evaluation and treatment until after undergoing Bränemark endosseous implant placement to supplement the previously existing mandibular staple bone plate implant. This supplemental treatment was the surgeon's attempt to resolve the patient's complaint of loose dentures. Creativity with implant biomechanics and prosthodontic design were necessary to restore the patient, in a predictable manner, to normal function. A fixed, detachable cast overdenture bar rigidly connected to all the implants was constructed utilizing resilient attachments to retain the tissue‐supported mandibular overdenture. A presurgical prosthodontic evaluation could have averted many of the problems encountered with treatment. More effective conventional prosthodontic treatment may have resolved the patient's complaints and eliminated the need for additional implant placement.
Patient‐Centered Competency‐Based Education in Fixed Prosthodontics
Authors: Nimmo Arthur , Knight G. William
Published: March 2005

Revision of a traditional fixed prosthodontic curriculum was undertaken in response to observed private practice patterns, recent literature in fixed prosthodontics, and an increasingly crowded dental school curriculum. The revision was further motivated by the commitment of the faculty to become patient‐centered in all components of instruction. The resultant preclinical and clinical curriculum emphasizes patient care activities and minimizes student‐generated laboratory products. This program is characterized as patient‐driven, competency‐based, and criterion‐referenced, and it places heavy reliance on validated pedagogical strategies, which include evaluation of self and peers. The curriculum requires the development of good communication skills with peers, faculty, and commercial laboratories and creates time for the student to develop critical patient care skills without requiring more curriculum time. The new fixed prosthodontic curriculum appears to be consistent with current private general practice, national licensing examinations, and the recommendations of the Institute of Medicine's report to dental education.
Controlled Retainer‐Screw Access Placement for Screw‐Retained Implant Prosthesis
Authors: Cohen Stephen R. , Lawrence Stanley , Orenstein Jonathan H. , Appleby David C. , Blitzer Robert M.
Published: March 2005

An implant‐supported prosthesis is often secured to the underlying gold cylinders by retaining screws. There must be access to these screws from the oral surface of the prosthesis. Conventional preparation of this access is from the oral surface. This approach is difficult because the underlying gold cylinder is obscured. It may be damaged by a rotary cutting instrument as the access is prepared above it, because the cylinder cannot be seen during the preparation. Alternatively, the access hole may be unnecessarily enlarged in an attempt to find the cylinder. This loss of structure may weaken the prosthesis. A new approach, using 18‐gauge stainless steel wire as a rotary cutting instrument, permits preparation of the access chamber from the intaglio surface of the prosthesis. This reduces risk of damage to the gold cylinder and is less destructive to the overlying material.
Fatigue of Resin Cement–Base Metal Alloy Bond Strength
Authors: White Shane N. , Golshanara Alan
Published: March 2005

Purpose Strong durable bonds between resin cements and metal alloys are critical to the success of resin‐bonded, resin‐veneered, or resin‐retained prostheses. However, few comprehensive, comparative evaluations of materials or the fatigue effects of thermal cycling have been reported. The rate of strength loss may be a more important predictor of long‐term success than bond strength. The purpose of this study was to investigate the effects of artificial aging by thermal cycling and resin cement type on the bond strengths to a base metal alloy.

Materials and Methods This study investigated the effect of the number of thermal cycles (0, 1, 10, 100, 1,000 and 10,000) on the bond strengths of nine fixed prosthodontic resin cements. Specimens were assigned randomly to thermal cycle number/cement type test groups. Cylinders of a base metal alloy were bonded in an end‐to‐end configuration. One end of each bonded specimen was insulated, and the specimen was thermal cycled. Then, the bonds were tested in shear and bond strengths calculated.

Results Two‐way ANOVA revealed that the effects of cement type, the number of thermal cycles, and their interaction all significantly affected bond strength (p < .0001). Multiple range analysis showed that some cements had significant trends to lose bond strength with thermal cycling (p < .05), while others did not (p > .05).

Conclusions Both the type of resin cement and the amount of thermal cycling influenced bond strength to a base metal alloy. Some materials displayed more rapid loss of bond strength than others.
The Bond Strength of an Adhesive Resin Luting Cement to a Variety of Surface Treatments of a High‐Palladium Copper Alloy
Authors: Lynde Thomas A. , Whitehill J. Michael , Coffey James P. , Meiers Jonathan C.
Published: March 2005

Purpose This study evaluated the tensile bond strength of a bisphenol glycidyl methacrylate (Bis‐GMA) resin luting cement with four different surface treatments of a high Pd‐Cu alloy.

Materials and Methods For each surface treatment type (tin‐plated, porcelain furnace oxide, air‐abraded, and finished‐only), 15 opposing half‐dumbbell‐shaped samples were cast and prepared in new Pd?Cu alloy. Samples were luted with a Bis‐GMA resin luting cement at a film thickness of 80 μm using a custom alignment apparatus. Samples were stored in distilled water at 37°C for 24 hours, thermocycled for 1,000 cycles, and then stored for 30 days in distilled water at 37°C. Samples were then subjected to fracture in tension at a loading rate of 0.5 cm/min with the bond strengths calculated in megapascals (MPa). The fractured surfaces were examined using stereomicroscopy and scanning electron microscopy at various magnifications ranging from 5.5x to 500x to determine the type of bond failure (adhesive, cohesive, or mixed).

Results Tensile bond strengths (mean ± SD MPa) were: tin‐plated, 30 ± 15.7; porcelain furnace oxide, 23 ± 8.6; air‐abraded, 8 ± 8.1; and finished‐only, 4 ± 4.5. Statistical analysis of the tensile bond values using an ANCOVA and Tukey's multiple comparison test at a significance level of 0.05 indicated that there was no difference between the tin‐plated and the furnace oxide groups, as well as between the air‐abraded and the furnace oxide groups. However, there was significant difference between the tin‐plated, the air‐abraded, and the finished‐only groups. The observed bond failures were predominantly mixed and cohesive in nature with only one adhesive failure.

Conclusions There was no significant difference in the tensile bond strengths between the tin‐plated group or the porcelain furnace oxide surface group. This suggests that the less‐technique‐sensitive porcelain furnace oxide surface treatment offers an alternative for achieving high metal‐resin bonds to a high Pd?Cu alloy.
Effect of Resin/Fluoride and Holmium: YAG Laser Irradiation on the Resistance to the Formation of Caries‐Like Lesions
Authors: Holt Raleigh Alton , Nordquist Robert E.
Published: March 2005

Purpose This study compared the effects of a combination of a topical application of resin/NaF mixture and holmium‐doped yttrium aluminum garnet (HO:YAG) laser energy with untreated control sites for their resistance to acid destruction/mechanical challenges of root surfaces adjacent to restorative margins.

Materials and Methods Forty‐eight extracted human teeth were prepared for restorations with coronal margins in enamel and the apical margins on root surfaces. Four types of restorative materials were used. One half of the restorative/root surface margins were treated with an application of nonfilled resin/fluoride mixture and holmium‐doped yttrium aluminum garnet laser irradiation; the remaining portion served as the untreated control for each tooth. Acid (10% formic) and mechanical (air sandblaster) challenges were used to test the effects of these treated sites to their controls and to other types of restorative/root surface margins. The depth of root surface loss within 0 to 2 mm apical from the restorative margins was measured and evaluated after 24, 48, and 72 hours of acid exposures.

Results The measurements of tooth loss for the 24‐ and 48‐hour acid‐exposure cycles were subjected to statistical analysis (ANOVA) using a paired t test for the variables. The variables, depth of tooth surface loss for the control sites was compared with the depth of loss of the treated sites on opposing sides of each tooth. The depth of tooth surface loss for the control sites had an average mean of 0.35 (0.25) mm for the 24‐hour acid exposures, with the opposing treated sides having a mean of 0.053 (0.05) mm (significant at the 0.05 level). The 48‐hour acid‐exposure results showed significant increased tooth loss for the control sites, but minimum additional loss on the treated sites. The control sites showed an average mean of 1.16 (0.24) mm and a mean of 0.095 (0.103) mm for the treated areas, significant at the 0.05 level. No measurements were made for the 72‐hour cycle groups of composite and amalgam alloy restorations because of the loss of most of the filling materials in the control sites. The control groups of crowns showed an average mean loss of 2.06 (0.37) mm with only 0.20 (0.19) mm surface loss for the treated sites. The paired t test for variables indicated no significant differences of tooth surface loss between various types of restorative margins used in this study.

Conclusions HO:YAG laser energy irradiation after application of resin/NaF to restorative margins and adjacent areas showed a significant increased resistance to acid/mechanical destruction on cementum‐dentin root surfaces. The integrity of the restorative/dentin margins were maintained after extended exposures to formic acid and mechanical challenges.
Fabrication of Acrylic Resin Copings for CeraOne Provisional Restorations
Authors: Balshi Thomas J. , Wolfinger Glenn J.
Published: March 2005

A technique is described for fabricating autopolymerizing acrylic resin copings for CeraOne provisional restorations. This method has the advantage of providing a chemical bond rather than only a bond between the mechanical coping and the relined provisional crown, as is the case when using the provisional components supplied by the manufacturer. The technique describes provisionalization at the time of stage II surgery. This type of coping can also be used after a period of soft tissue healing when a healing abutment is employed. The benefits of the procedure include increased patient satisfaction and reduced chair time for repairs.
In vitro Enamel Demineralization and The Marginal Gap of Simulated Cast Restorations With Three Different Cements
Authors: Wu Ynlow H. , Hutton John E. , Marshall Grayson W.
Published: March 2005

Purpose This study investigated 1) the relationship between marginal gap sizes and enamel demineralization, and 2) the influence of three cements on this enamel demineralization.

Materials and Methods Horizontal sections of 60 noncarious, freshly extracted human third molars were randomly assigned to one of four groups. Simulated cast restorations were attached to the specimens with 1) zinc phosphate cement, 2) glass ionomer cement, 3) composite resin cement, or 4) no cement (control). The tooth/restoration gaps were controlled at 51, 102, and 204 μm. The specimens were incubated for 16 weeks in buffered lactic acid gelatin to induce demineralization. Photomicrographs were obtained from sections of each sample using a polarized light microscope. Three evaluators measured wall and primary enamel lesion depths allowing for the determination of a demineralization ratio (DR). Data were analyzed by repeated‐measures ANOVA (α= 0.05).

Results The between‐evaluator effects were not significant. All evaluators agreed that DR was significantly related to cement (p= .0001) but not to marginal gap size. The resin cement had the smallest DR (0.7 ± 0.3), and the control group had the greatest (4.4 ± 2.0).

Conclusions The presence of any one of the three investigated cements resulted in decreased demineralization. The amount of demineralization was unaffected by marginal gap size.
Construction of a Custom‐Shaded Interim Denture Using Visible‐Light‐Cured Resin
Authors: Haeberle C. Brent , Khan Zafrulla
Published: March 2005

A patient treatment is presented to demonstrate a technique using visible‐light‐cured (VLC) resin to create a characterized denture base for an interim denture. This indication for characterization is routinely seen with African‐Americans with dark‐pigmented gingiva. Using a combination of blue VLC tray resin and pink VLC denture base resin, the mixture achieves a darker‐colored denture base. This technique was used for the fabrication of an interim denture for a patient who required an immediate interim denture. The prosthesis was worn during the healing phase and allowed the patient to function while the definitive prosthesis was being fabricated.
Oral Rehabilitation of a Patient With Amelogenesis Imperfecta
Authors: Thompson Geoffrey A. , Schwartz Jerry M.
Published: March 2005

A patient with Type I hypoplastic patterned amelogenesis imperfecta, subtype D, presented for prosthodontic evaluation. This article describes the developmental and pathophysiological background of this disease. A clinical report describing the diagnosis, treatment planning, and dental rehabilitation of the patient is reviewed.
Introduction of a Denture Injection System for Use With Microwaveable Acrylic Resins
Authors: Phoenix R. D.
Published: March 2005

Recently, an injection system for use with microwaveable denture base resins was introduced. Preliminary evaluation of this system was performed at a university‐based dental laboratory. This article provides a description of the complete denture fabrication technique, as well as observations regarding its design and practicality.
Defining Predoctoral Prosthodontic Curriculum: A Workshop Sponsored by The American College of Prosthodontists and the Prosthodontic Forum
Authors: Nimmo Arthur , Woolsey Gerald D. , Arbree Nancy S. , Saporito Robert A. , Cooney Joseph P.
Published: March 2005

Prosthodontic educators participated in a workshop held at The American College of Prosthodontists annual session in Kansas City, MO, in October 1996. Their goal was to review elements of the predoctoral prosthodontic curriculum to establish a consensus on the levels of expected skill and knowledge. Skill components were designated at the competency and exposure levels, while knowledge components were designated at the understanding and familiarity levels. The workshop recommendations were distributed to American and Canadian dental schools and the communities of interest for comments in January 1997. The workshop recommendations were reviewed and finalized at the American Association of Dental Schools annual meeting in Orlando, FL, in March 1997. The recommendations may be used by dental educators to prioritize curricular elements in relation to limited time dedicated to the prosthodontic curriculum. Outcomes assessment methods will be needed to ensure competency in the new dentist.
An Alternative Technique for Mandibular Advancement Prosthesis Fabrication
Authors: Sadan Avishai , Novoselsky Alan , Rogers William A.
Published: March 2005

One of the conservative and successful modalities of treatment for obstructive sleep apnea is the mandibular advancement prosthesis. This prosthesis engages teeth on both dental arches for retention and stability. This article describes a technique that allows that fabrication of such a prosthesis in one piece and in a single laboratory step. This may be beneficial in reducing the laboratory time required for fabrication of such a prosthesis.
A Simple Toothbrush Modification for Easier Implant‐Supported Prosthesis Hygiene
Authors: Duncan Jacqueline P. , Taylor Thomas D. , Kosis Diane L.
Published: March 2005

The lingual aspect of mandibular anterior implant‐supported prostheses is often difficult to reach for adequate hygiene. The following technique describes modification of an end‐tufted toothbrush to allow for improved access into to difficult‐to‐reach areas.
Evaluation of Working Distances at a 1:1 Reproduction Ratio for Seven Popular 35‐mm Dental Camera Systems
Authors: Chuman Ted A. , Hummel Susan K. , Bokmeyer Tim J.
Published: March 2005

Purpose The purpose of this study was to evaluate the effectiveness of seven camera systems in producing accurate intraoral images.

Materials and Methods Seven camera systems marketed for use in clinical dentistry were compared in terms of their working distances at a 1:1 reproduction ratio.

Results Each of the systems provided slides of acceptable quality for both direct view and indirect buccal mirror view when used with the customary 90‐mm to 105‐mm focal‐length lenses and the electronic flash units appropriate for each model. Using the manufacturers' recommended settings for each exposure, some differences in the quality of the resulting slides were noted. The color slides produced by three of the camera systems were slightly underexposed, but still clinically acceptable.

Conclusion The camera systems with longer working distances, especially for the indirect buccal mirror view and when using the lateral flash, permit the photographer to position the camera with greater ease so that the slide image is an acceptable reproduction of the actual clinical view.
Wiropress SL: A Multipurpose Dental Pressure Vessel With Transparent Chamber
Authors: Ewoldsen Nels , Koka Sreenivas
Published: March 2005

Pneumatic vessels used in dentistry provide a pressurized environment to enhance the outcome of many laboratory procedures. A pressurized environment directs volume loss associated with polymerization shrinkage, minimizes air inclusions in powder/liquid mixtures, raises the boiling point of liquids, and facilitates flow of impression and replication materials, improving surface detail. The following report illustrates the usefulness of a reliable pneumatic vessel during denture base repair resin processing and replication of pattern details.
Evaluation of the Accuracy of Solid Implant Casts
Authors: Wee Alvin G. , Schneider Robert L. , Aquilino Steven A. , Huff Thomas L. , Lindquist Terry J. , Williamson Derrick L.
Published: March 2005

Purpose Materials used to fabricate the most dimensionally accurate implant casts have not been identified experimentally. The purpose of this investigation was to examine the dimensional accuracy of implant casts fabricated with different materials. Measurements of linear horizontal dimensional change and strain produced on a master framework were evaluated and correlated.

Materials and Methods A master framework was fabricated to fit an aluminum five‐implant model. Forty polyether implant impressions of the aluminum model were randomly grouped and poured in either Vel‐mix, Die Keen, Resin Rock, or Low Fusing Alloy. A digital veneer caliper was used to measure linear distance between the most distal abutments on each of the experimental implant casts and the master model. In addition, strain values were recorded from strain gauges bonded in the mesiodistal axis of the framework, which was secured by prosthetic retaining screws torqued to 10 Ncm.

Results A one‐way ANOVA showed a significant difference among the four die materials in dimensional change of the experimental casts (p= .0001). A post‐hoc Duncan's multiple‐range test (p < .05) showed that casts fabricated with Low Fusing Alloy had the least linear dimensional change from the master cast, but the material exhibited the greatest dimensional variability. A MANOVA (Wilks' Lambda) showed significant differences in strain on the framework based upon die material (p= .015). A post‐hoc Duncan's multiple‐range test (p < .05) showed that Resin Rock casts induced significantly less strain on the framework than the other materials. Negligible correlation was found between the linear horizontal dimensional change and the total absolute strain on the framework.

Conclusion Experimental implant casts made of Resin Rock minimized strain on the master framework and decreased the amount of framework distortion on casts of this material. Low Fusing Alloy yielded accurate casts, but highly variable linear dimensional changes in the horizontal dimension may preclude its clinical benefit.
An Interactive Multimedia Solution to Learning Removable Partial Denture Design
Authors: Lechner Sybille K. , Thomas Graham A. , Bradshaw Michael
Published: March 2005

Surveys of the dental profession and dental laboratories show that up to 60% of cases received by laboratories have little or no input from dentists into the design of their patients' removable partial dentures (RPD). Thus, there is a clear mandate for dental schools to teach RPD design in new ways that will give their students confidence and allow their graduates to approach the task readily and easily. This computer‐aided learning program addresses that need. In designing it, we have exploited the unique properties of computers as a learning tool. The program uses Quicktime VR to simulate a three‐dimensional perspective of diagnostic casts. It is also possible to incorporate animated diagrams to illustrate various points. Control of timed answers promotes the use of inquiry‐based learning and allows the program to be interactive and completely problem‐oriented. Students can practice at their own pace, on a variety of virtual cases, and thus learn the craft behind the art of designing RPDs. With this foundation, discussions with experts in the field regarding the patients they treat in senior years and as graduates can be conducted at a higher and more productive level. Student evaluation so far has been very encouraging.
Post‐impression Preparation to Prevent Fracture to Isolated Abutments with Extensive Bone Loss in Master Casts
Authors: Sato Yuuji , Tsuga Kazuhiro
Published: March 2005

A post‐impression preparation technique can be used for preventing fracture of isolated abutments in master casts with extensive bone loss. This technique involves using a sharp knife to trim the impression obliquely at the clinical cervical line, creating a 1‐ to 2‐mm‐width bevel, followed by the insertion of a dowel pin into the abutment for reinforcement. This technique enlarges the abutments' diameter at the clinical cervical line and increases the resistance to breakage without altering the shape of critical areas.
Effect of Polymerization Mode on Bond Strengths of Resin Adhesive/Cement Systems
Authors: Swift Edward J. , May Kenneth N. , Wilder Aldridge D.
Published: March 2005

Purpose The purpose of this study was to examine the effect of resin adhesive/cement system primer and cement polymerization mode (auto‐ vs dual‐polymerized) on the shear bond strength to dentin.

Materials and Methods Dentin surfaces of 90 bovine teeth were polished to 600 grit. The dentin was etched for 15 seconds with phosphoric acid, rinsed, and blotted. Three adhesive systems, All‐Bond 2, Prime & Bond 2.1 Dual‐Cure, or Scotchbond Multi‐Purpose Plus, were applied. Three primer polymerization methods were used with each system: dual‐polymerized, autopolymerized, or strictly following manufacturers' recommendations. Resin cements, which were also either auto‐ or dual‐polymerized, were applied to dentin using gelatin capsules. Shear bond strengths were determined using an Instron universal testing machine.

Results The greatest bond strength, 15.4 MPa, was found with the Scotchbond system when the primer was dual‐polymerized and the cement was autopolymerized. The lowest bond strength, 7.5 MPa, was found with All‐Bond 2/Duo‐Link, when the primer and cement were dual‐polymerized. The autopolymerization mode produced the highest mean bond strength for All‐Bond 2, while dual‐polymerization of primer and cement resulted in the highest mean bond strength for Prime & Bond 2.1. Scotchbond Multi‐Purpose Plus was least affected by the polymerization method. Two‐way ANOVA showed that the interaction between the type of adhesive system and the method of polymerization significantly influenced bond strength (p= .0001).

Conclusions The effect of the primer polymerization method on ultimate bond strength was different for each adhesive system evaluated. More research is needed to elucidate the interaction between adhesive system and method of polymerization on bonding of resin cements to dentin.