Biomedical subjects
Publications and source records attributed to W D Sneed.
Fabrication of provisional restorations for teeth prepared to receive porcelain veneers can be a time-consuming and difficult task. This article describes a simple, quick, and predictable procedure to make these restorations. A clinical case is presented to illustrate the technique.
STATEMENT OF PROBLEM: Many different bonding systems are currently available that may be used to bond composite to base metal alloy. PURPOSE: This study measured and compared bond strengths of composite with a base metal alloy using 8 modern dentin bonding systems. MATERIAL AND METHODS: Base metal alloy buttons were imbedded in acrylic and ground with 120, 400, and 600 grit sandpaper, respectively. Metal surfaces were air abraded for 5 seconds with 50 microm aluminum oxide, washed for 5 seconds under running tap water, then dried with compressed air. Specimens were arbitrarily divided into 8 groups of 10 specimens. Each group was treated with 1 of 8 dentin bonding regimens. A hybrid composite (Herculite) was placed onto the treated metal surface and light polymerized. Specimens were incubated at 37 degrees C in distilled water for 2 hours. Shear bond strengths were measured and the collected data subjected to an ANOVA, followed by multiple t -tests. RESULTS: All-Bond 2 exhibited the highest mean shear bond strength and Panavia 21 with primer had the lowest in the tests conducted. CONCLUSION: All-Bond 2 demonstrated significantly higher shear bond strengths over all materials tested, except 3M Single Bond and Optibond FL. No significant difference was noted between the single component and the multicomponent bonding systems.
Cervical erosion defects, particularly those of extensive size that are located in an area where control of the operative field is difficult, can present a significant restorative challenge. This article describes an indirect restorative technique to solve this problem. Following tooth preparation, an indirect restoration is luted to the tooth and the margins are finished and polished. Using an indirect technique minimizes operative field isolation time and the total chairside time required to restore the tooth. Clinical cases are presented to illustrate this technique.
The degree of polymerization, determined by surface hardness, has been related to the gingival marginal adaptation of posterior composite resin restorations. Poor marginal adaptation results from marginal leakage and failure of the restoration. This study compared the degree of polymerization, measured by microhardness, of a microfilled composite resin placed by use of different matrices. The effect on polymerization with the curing light in two positions was also evaluated.
During a 15-week period, six full-time faculty members supervised the replacement of amalgam restorations by clinical dental students. The tooth numbers, the amalgam surfaces replaced, the reasons for replacement, and the instructors were compared. The students removed 956 surfaces of amalgam from 436 teeth. The primary reasons cited for replacement were marginal breakdown (69%) and caries (33%).
Six maxillary anterior teeth demonstrating severe chemomechanical erosion were restored using a minimal preparation design and a castable ceramic. Facial and lingual erosion prevented the development of the opposing wall retention and resistance form needed for traditionally cemented ceramic or porcelain-fused-to-metal crowns. Therefore, a dentin/enamel bonding system was used to condition the enamel and dentin simultaneously prior to cementation of an etched and silanated castable ceramic restoration. A resin cement was used as the luting agent.
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The effect of oral ambient air on shear strength to etched enamel and dentin was determined for OptiBond FL (Kerr Corp., Orange, CA) and Prodigy resin composite (Kerr Corp.). Enamel and dentin specimens of extracted human teeth were treated both in a dry environment and after exposure to oral humidity according to manufacturer's instructions. Shear strengths of this system are 22.6 MPa for etched, dry enamel; 22.2 MPa for etched, wet enamel; and 18.4 MPa for etched, dry or wet dentin. Differences in shear strengths between the wet and dry enamel or the wet and dry dentin were not significant. Multiple Student's t-tests were used for statistical analysis. Fracture modes for all specimens were examined under a stereomicroscope. Within the parameters of this in vitro study, OptiBond FL was not affected by oral humidity.
The newest generation of bonding systems consolidates multiple components into fewer containers in order to simplify clinical procedures and save clinicians time. Six newer adhesive systems (Scotchbond Multi-Purpose Plus, PROBOND, OptiBond FL, Prime & Bond, One Step, and Tenure Quik) were tested for in vitro shear bond strength (SBS) of a hybrid composite to both superficial and deep dentin at 24 hours and 6 months employing a pushout test method. Results showed significant differences in SBS between superficial and deep dentin for both 1-day and 6-month values for all adhesive systems except Tenure Quik. The SBS of OptiBond FL increased significantly for both superficial and deep dentin after 6 months' storage in 37 degrees C water. None of the other adhesive systems showed a significant change in SBS at 6 months. There appear to be several advantages to the testing method.