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Biomedical subjects

J P Duncan

Publications and source records attributed to J P Duncan.

11 recordsLinked to original sources
PubMed2001

Teaching an abbreviated impression technique for complete dentures in an undergraduate dental curriculum.

STATEMENT OF PROBLEM: Traditional methods for teaching complete denture fabrication are time-consuming, difficult to master, and not used by many general practitioners. PURPOSE: This study compared the efficacy of traditional denture fabrication techniques with a more abbreviated method in a dental school setting. MATERIAL AND METHODS: A retrospective record review of 80 completely edentulous patients treated by predoctoral dental students was completed. Forty patients were treated with traditional denture techniques; the other 40 patients were treated with an abbreviated method. The data abstracted included the number of visits to completion and the number of postinsertion visits and relines required within the first 3 months after delivery. A Wilcoxon rank sum test was performed to determine statistical significance between the groups with regard to number of visits for fabrication and postinsertion adjustments. A test for a difference in proportions by using the normal approximation to the binomial distribution was performed for statistical analysis of the incidence of relines. RESULTS: The abbreviated denture technique resulted in a statistically significant difference in the number of visits for fabrication (P<.01) and postinsertion adjustments (P<.05.) There was no difference (P=.39) in the number of relines between the 2 groups. CONCLUSION: Teaching the abbreviated complete denture technique in an undergraduate dental clinic decreased the number of appointments necessary to complete denture therapy without increasing the number of adjustments or reline procedures.

Appointments and Schedules↗
PubMed2000

Fiber-reinforced composite framework for implant-supported overdentures.

This article presents a new method for fabricating a framework for an implant-supported overdenture using unidirectional fiber-reinforced composite. This procedure eliminates the need for a traditional metal alloy framework. The fiber-reinforced composite framework has the advantages of lower cost, less time and materials needed during fabrication, minimal potential for toxicity to the technician and patient, and a more esthetic metal-free final result.

Composite Resins↗
PubMed1998

Retention of parallel-sided titanium posts cemented with six luting agents: an in vitro study.

PURPOSE: This in vitro study compared the effectiveness of 6 luting systems on the retention of prefabricated titanium posts. MATERIAL AND METHODS: A total of 120 single-rooted teeth were sectioned at the cementoenamel junction and treated endodontically. Roots were mounted in copper cylinders, and prefabricated, parallel-sided titanium posts were cemented according to the manufacturer's instructions. Two resin-ionomer hybrid cements and 2 resin cements were tested with corresponding dentin bonding agents. A glass ionomer cement was also tested, and zinc-phosphate cement served as the control. Samples were tested in an Instron universal testing machine to catastrophic tensile failure. RESULTS: Advance cement with Prime and Bond systems was found to be statistically more retentive than all other groups tested (P < .05). Cement It with Bond It and Permalute with Permalute Primers A and B systems demonstrated significantly greater retention than Ketac Cem cement, Resinomer with One-Step system and zinc-phosphate cement (P < .05). There was no statistically significant difference among Ketac Cem cement, Resinomer with One-Step system, and zinc-phosphate cement.

Analysis of Variance↗
PubMed1998

Preimpregnated, fiber-reinforced prostheses. Part II. Direct applications: splints and fixed partial dentures.

This article is the second in a series that describes the development, physical properties, and clinical applications of fiber-reinforced composite materials. The development of fiber-reinforced composite technology has opened new avenues for fabricating direct tooth replacements and splints that are esthetic and simple in design and execution and have the potential for excellent durability. Splinting techniques for hypermobile dentitions or postorthodontic retention and the replacement of anterior and posterior teeth using a groove preparation, a denture tooth, and a fiber-reinforced composite framework will be described.

Composite Resins↗
PubMed1998

Preimpregnated, fiber-reinforced prostheses. Part I. Basic rationale and complete-coverage and intracoronal fixed partial denture designs.

This is the first of two articles describing the development and use of a continuous fiber-reinforced composite as a framework for the fabrication of fixed partial dentures and splints. The chemical composition and physical structure of the fiber-reinforced composite, along with the progression and development of a variety of fiber-reinforced composite materials, are discussed. Criteria for case selection, tooth preparation, and the clinical and laboratory procedures required for partial- or complete-coverage fixed partial denture fabrication and delivery are described.

Composite Resins↗
PubMedDate not supplied

Retentiveness of dental cements used with metallic implant components.

There is limited dental literature evaluating the retentive capabilities of luting agents when used between metal components, such as cast metal restorations cemented onto machined metal implant abutments. This study compared the retentive strengths of 5 different classes of luting agents used to cement cast noble metal alloy crowns to 8-degree machined titanium cementable implant abutments from the Straumann ITI Implant System. Sixty prefabricated 5.5-mm solid titanium implant abutments and implants were used; 30 received the standard surface preparation and the other 30 received an anodized surface preparation. Anodized implant components were used to reflect current implant marketing. Sixty castings were fabricated and randomly paired with an abutment and implant. A total of 12 castings were cemented onto the implant-abutment assemblies for each of the 5 different luting agents (zinc phosphate, resin composite, glass ionomer, resin-reinforced glass ionomer, and zinc oxide-non-eugenol). After cementation, the assemblies were stored in a humidor at room temperature prior to thermocycling for 24 hours. Each casting was pulled from its respective abutment, and the force at which bond failure occurred was recorded as retentive strength. A statistically significant difference was found between the 5 cements at P < or = .001. Of the cements used, resin composite demonstrated the highest mean retentive strength. Zinc phosphate and resin-reinforced glass-ionomer cements were the next most retentive, while glass ionomer and zinc oxide-non-eugenol cements demonstrated minimal retention. In addition, retention was not altered by the use of an anodized abutment surface.

Adhesiveness↗