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Biomedical subjects

C J Goodacre

Publications and source records attributed to C J Goodacre.

At least 19 recordsLinked to original sources
PubMed1999

Effects of smoking on implant success in grafted maxillary sinuses.

STATEMENT OF THE PROBLEM: Cigarette smoking has been identified as a significant risk factor for dental implant treatment. PURPOSE: This retrospective study evaluated the effect of smoking and the amount of cigarette consumption on the success rates of the implants placed in grafted maxillary sinuses. MATERIAL AND METHODS: Sixty patients (16 smokers and 44 nonsmokers) were evaluated for the effects of smoking on osseointegrated implants placed in 84 grafted maxillary sinuses that contained a total of 228 endosseous root-form implants. Seventy implants were placed in 26 maxillary sinuses in smokers, whereas 158 implants were placed in 58 sinuses in nonsmokers. The number of implant failures and the amount of cigarette consumption were recorded. RESULTS: Of the 228 implants, 205 (89.9%) remained in function, after a mean follow-up period of 41.6 months (2 to 60 months). There was a significantly higher cumulative implant success rate in nonsmokers (82.7%) than in smokers (65.3%) (P =.027). Overall cumulative implant success rate was 76%. There was no correlation between implant failures and the amount of cigarette consumption (P >.99). CONCLUSION: Within the limitations of this study, cigarette smoking appeared to be detrimental to the success of osseointegrated implants in grafted maxillary sinuses regardless of the amount of cigarette consumption.

Adult↗
PubMed1999

Clinical complications of osseointegrated implants.

STATEMENT OF PROBLEM: There is no comprehensive review of the literature that identifies the complications reported in clinical dental implant studies. PURPOSE: This article attempted to determine the types of complications that have been reported and to provide data regarding their frequency. METHODS: All available clinical studies from 1981 to 1997, published in English or with English abstract, that presented success/failure data regarding implant treatment were evaluated to determine the types of reported complications and to quantify implant loss as it relates to type of prosthesis, arch, time, implant length, and bone quality. RESULTS: Greater implant loss occurred with overdentures than with other types of prostheses. There was greater loss in the maxilla than mandible with fixed complete dentures and overdentures, whereas little arch difference was noted with fixed partial dentures. Implant loss increased with short implants and poor bone quality. The time of implant loss (preprosthetic vs postprosthetic) varied with type of prosthesis. Surgical complications included neurosensory disturbance, hematoma, mandibular fracture, hemorrhage, and tooth devitalization. Initial and long-term marginal bone changes were identified. Peri-implant soft tissue complications included dehiscence, fistulas, and gingival inflammation/proliferation. Mechanical complications were screw loosening/fracture, implant fractures, framework, resin base and veneering material fractures, opposing prosthesis fractures, and overdenture mechanical retention problems. Some studies also presented phonetic and esthetic complications. CONCLUSIONS: Although the literature presents considerable information on implant complications, variations in study design and reporting procedures limited the available data and therefore precluded proper analysis of certain complications.

Dental Arch↗
PubMed1999

Clinical methods for evaluating implant framework fit.

STATEMENT OF PROBLEM: Passive fit of implant-supported-prosthesis frameworks has been suggested as a prerequisite for successful long-term osseointegration. However, there are no scientific guidelines as to what is passive fit and how to achieve and measure it. PURPOSE: The purpose of this article is to discuss passive fit and to review the various clinical methods that have been suggested for evaluating implant framework fit.Methods. The dental literature was reviewed to identify the clinical methods that have been used to evaluate implant framework fit. CONCLUSIONS: The suggested levels of passive fit are empirical. Numerous techniques have been advocated to evaluate the prosthesis-implant interface, but none individually provides objective results. It is suggested that clinicians use a combination of the available methods to minimize misfits.

Dental Alloys↗
PubMed1998

Using a colorimeter to develop an intrinsic silicone shade guide for facial prostheses.

PURPOSE: To determine if using CIE L*a*b* color measurements of white facial skin could be correlated to those of silicone shade samples that visually matched the skin. Secondly, to see if a correlation in color measurements could be achieved between the silicone shade samples and duplicated silicone samples made using a shade-guide color formula. MATERIALS AND METHODS: A color booth was designed according to ASTM specifications, and painted using a Munsell Value 8 gray. A Minolta colorimeter was used to make facial skin measurements on 15 white adults. The skin color was duplicated using custom-shaded silicone samples. A 7-step wedge silicone shade guide was then fabricated, representing the commonly encountered thicknesses when fabricating facial prostheses. The silicone samples were then measured with the Minolta colorimeter. The readings were compared with the previous L*a*b* readings from the corresponding patient's skin measurements, and the relative color difference was then calculated. Silicone samples were fabricated and analyzed for three of the patients to determine if duplication of the visually matched silicone specimen was possible using the silicone color formula, and if the duplicates were visually and colorimetrically equivalent to each other. The color difference Delta E and chromaticity was calculated, and the data were analyzed using a coefficient-of-variation formula expressed by percent. A Pearson Product Moment Correlation Coefficient was performed to determine if a correlation existed between the skin and the silicone samples at the p < or = .05 level. RESULTS: The highest correlation was found in the b* dimension for silicone thicknesses of 1 to 4 mm. For silicone thicknesses of 6 to 10 mm, the highest correlation was found in the L* dimension. All three dimensions had positive correlations (R2 > 0), but only the 1-mm and 4-mm b* readings were very strong. Patient and silicone L*a*b* measurement results showed very little change in the a* axis, while the L* and b* measurements showed more change in their numbers, with changes in depth for all patient silicone samples. Delta E numbers indicated the lowest Delta E at the 1-mm depth and the highest Delta E at the 10-mm depth. All duplicated samples matched their original silicone samples to a degree that visual evaluation could not distinguish any color differences. Using volumetric measurements, a shade guide was developed for all 15 patients. CONCLUSIONS: There was good correlation between the patient's colorimeter measurements and the silicone samples, with the b* color dimension the most reproducible, followed by the L* and the a*. Silicone samples at 6, 8, and 10 mm matched the patient the best, and this study showed that silicone samples can be duplicated successfully if a good patient-silicone match is obtained. Rayon flocking fibers and liquid makeup are effective at matching facial prostheses and can be used to develop a simple shade guide for patient application.

Color↗
PubMed1997

Prosthodontic considerations when using implants for orthodontic anchorage.

STATEMENT OF PROBLEM: The use of implants for orthodontic anchorage can produce superior preprosthetic tooth positions. Their use often requires a crown or prosthesis to be fabricated for use as a connection between the orthodontic devices and the implant. PURPOSE: In this article, factors that affect the design of prostheses required for orthodontic movement and examples of prosthesis designs and materials, based on the authors' experience, are presented.

Dental Implantation, Endosseous↗
PubMed1996

An evaluation of microwave-polymerized resin bases for removable partial dentures.

PURPOSE: The hardness, porosity, and adaptation of removable partial dentures fabricated with one heat-polymerized denture base resin and two resins designed for microwave polymerization were evaluated. MATERIALS AND METHODS: Five prostheses were evaluated for each resin. Adaptation of the denture bases to the master cast was evaluated by spatial orientation and mean weight of residual impression material. The prostheses were than embedded in epoxy resin and sectioned for evaluation of resin hardness (Knoop hardness) and microporosity. RESULTS: There were no significant differences in the adaptation of the acrylic resin bases for Acron MC and Ch Lucitone. There was no significant difference in the mean Knoop hardness values for any of the resin bases near and away from the metal. None of the denture bases showed porosity greater than 100 microns. CONCLUSIONS: Both resin bases formulated for microwave polymerization were effectively polymerized around metal frameworks without adverse effects on resin hardness or porosity. Justi Denture Base material had poorer base adaptation than the other two resins.

Acrylic Resins↗
PubMed1995

Effect of two opaquing techniques and two metal surface conditions on metal-ceramic bond strength.

The optimal conditions for opaquing techniques during porcelain application have not been confirmed. In this study the metal-ceramic bond strength was measured among one porcelain and three dental alloys, namely a gold-platinum-palladium alloy, a silver-free gold-palladium alloy, and a base metal alloy, with two opaquing techniques (a single masking layer versus a thin overfired layer followed by a second masking layer). In addition, the opaque porcelain was fired over an oxidized and nonoxidized alloy surface for the silver-free gold-palladium alloy. No significant differences in bond strength were recorded between the two opaquing techniques with the gold-platinum-palladium and base metal alloys. There was no substantial differences between the two opaquing techniques when opaque was applied over an oxidized gold-palladium alloy surface and bond strengths were substantially greater over an oxidized surface. However, when the opaque was applied to a nonoxidized gold-palladium surface the two-layer technique created a significantly greater bond strength.

Chromium Alloys↗
PubMed1994

The prosthodontic management of endodontically treated teeth: a literature review. Part I. Success and failure data, treatment concepts.

Part I of this three-part literature review discusses the incidence of endodontic treatment required after prosthodontic procedures, whether crowns are needed on endodontically treated teeth, the primary purpose of posts, the causes of post and core failure, root fracture incidence data, and post design considerations. Pertinent questions are addressed based on the past 25 years of dental literature.

Crowns↗
PubMed1993

Recent graduates' and current dental students' evaluation of their prosthodontic curriculum.

This survey of recent graduates and third- and fourth-year dental students at Indiana University School of Dentistry determined whether the prosthodontic curriculum adequately prepared students for the prosthodontic portion of dental practice and whether there was material that should be added to or omitted from the prosthodontic curriculum. The survey evaluated 106 topics in the prosthodontic curriculum and areas related to prosthodontics. On the basis of their importance to the respondents, 59.4% of the topics were considered adequately emphasized, 2.9% of the topics were overemphasized and should be reduced in emphasis or eliminated, and 37.7% of the topics were underemphasized, which indicated the need to increase time devoted to these topics. Most of the underemphasized topics dealt with new materials, alternate techniques, private practice and its management, and the prosthodontic needs of special types of patients.

Curriculum↗
PubMed1993

Force-moment systems on single maxillary anterior implants: effects of incisal guidance, fixture orientation, and loss of bone support.

An engineering model of maxillary single anterior implants was developed to calculate the force-moment systems resulting from occlusal contacts. Analysis of a clinical example showed that flattening the incisal guidance and/or placing the implant in a more upright position reduced the moment and the labial component of the force but increased the intrusive component. The calculations are applicable to the design of implants and may help in the long-term evaluation of clinical success.

Algorithms↗
PubMed1991

Microleakage and shear bond strength of resin and porcelain veneers bonded to cast alloys.

Four resin veneering materials and four methods of retaining the veneer on metal castings were compared with metal ceramic restoration. Variations in microleakage were noted between the four resin materials retained by mechanical retention beads. When mechanical and chemical modes of a resin and porcelain veneer retention were compared, there was no microleakage with one mechanically and two chemically retained resin groups including one metal ceramic group. The resin materials tested understandably produced substantially lower shear bond strengths than the metal ceramic specimens. Higher shear bond strengths were recorded for the retentive beads than for the resins retained by three chemical bonding techniques. There was no direct correlation between microleakage and shear bond strength.

Acrylic Resins↗
PubMed1990

Predoctoral fixed prosthodontics education.

All current prosthodontic services will be needed well into the 21st century because millions of people are still without complete dentitions. However, knowledge of current and projected dental health needs indicates that the extent of usage of certain prosthodontic procedures will change because the number of edentulous patients will decrease. Presently there is considerable need and demand for extensive prosthodontic services and the need has been projected to grow. The demand for fixed prosthodontic services will likely increase in the future, particularly with the increased usage of new materials and treatment modalities. Recent data obtained from the American Dental Association Commission on Dental Accreditation indicate that failure rates on Part II of the National Board Dental Examinations and the prosthodontics section of Part II have remained relatively constant from 1980 to 1987. Total Part II failure rates for this time period have only ranged from 8.31 to 9.91 and on the prosthodontics section from 2.10 to 2.74. While these data do not predictably reflect clinical and technical skills or a knowledge of the most current didactic information, they do indicate that adequate knowledge had been provided to predoctoral students regarding the fundamental principles of prosthodontics. However, reductions have been made in prosthodontic curricular time. With the current escalation of knowledge in prosthodontics and allied areas and the increasing time constraints, it is becoming increasingly difficult to teach a thorough understanding of the basics and exposure to new developments. Any further reductions in curricular time will significantly compromise educational quality.

Curriculum↗
PubMed1990

Gingival esthetics.

Achieving the most desirable gingival appearance enhances the esthetic result achieved with fixed prosthodontic restorations and is most often realized when gingival health is optimized before treatment and gingival trauma is minimized during treatment. Methods of optimizing gingival appearance by avoiding soft tissue contact are discussed as are factors considered important to maintaining good gingival appearance when subgingival margins are necessary.

Dental Cavity Preparation↗
PubMed1989

Palladium-silver alloys: a review of the literature.

Since their introduction in 1973, the use of palladium-silver alloys has increased significantly and they now comprise a substantial part of the noble metal ceramic alloy sales in North America. Literature regarding various properties of this alloy system is presented with particular emphasis on castability, fit, and porcelain discoloration.

Dental Alloys↗