Faculty Bibliography

PURPOSE: To compare the adhesion of a flowable resin-based composite (RBC) vs. a condensable RBC to tooth structure using scanning electron microscopy (SEM). MATERIALS AND METHODS: Fifteen recently extracted human teeth were prepared for Class I restorations and equally divided into three groups. Group 1 was filled with Heliomolar bonded with Syntac Single Component. Group 2 was lined with Flow-It in addition to ALERT condensable RBC bonded with Bond-1 Primer/Adhesive. Group 3 was filled with ALERT bonded with Bond-1 Primer/Adhesive. All teeth were thermocycled, sectioned and evaluated for gap formation with the SEM. RESULTS: SEM at x15 demonstrated that restorations with the flowable RBC at the tooth/restoration interface showed no evidence of marginal gaps between the RBC material or at the underlying tooth structure. A significant difference (P < 0.05) in wall adaptation was found between Groups 2 and 3

The purpose of this study was to compare three-dimensional laser digitizing with subjective evaluations of wear in posterior resin-based composite restorations during a 24-month period. BACKGROUND: The authors describe an indirect method of analyzing wear in resin-based composite restorations. A computer-driven laser was used to scan stone casts of restorations and create three-dimensional computerized surface models of the teeth. A standard computer algorithm was used to superimpose the follow-up model images over the baseline model images and to calculate the amount of wear within 10 micrometers. METHODS: Patients were selected whose treatment plans required a Class II restoration. A total of 100 restorations were inserted at baseline and evaluated at six months, 12 months and 24 months. Polyether quadrant impressions were taken and casts were made. Twenty-one casts were selected for the three-dimensional laser digitizing technique. The same casts were evaluated via subjective evaluations using sets of 18 calibrated standard models, following the method developed by Leinfelder. RESULTS: Statistical analysis using the Wilcoxon test revealed significant differences (P < .01) between subjective wear evaluation and the three-dimensional laser digitizing wear analysis. CONCLUSION: The normalized three-dimensional laser digitizing technique is significantly more effective than subjective evaluations in establishing restoration wear rates

This in vitro study evaluates the marginal sealing ability of three different flowable composite systems at enamel and dentin margins, using sealants. Class V preparations were made on the facial surfaces in enamel and dentin/cement of 60 freshly extracted teeth, which were allotted randomly into six groups of ten. The control groups (I, II, and III) showed leakage in the majority of cases. However, Groups IV and V had very limited microleakage scores (2 of 30) in comparison to Group VI (p < 0.001, Mann-Whitney Test)

OBJECTIVE: The purpose of this investigation was to evaluate the microleakage of Class V lesions restored with a compomer material (Dyractflow) using 2 single-bottle bonding systems. METHOD AND MATERIALS: Sixty-four Class V cavity preparations were made on 32 sound, extracted human premolars, 1 preparation on the facial surface and 1 on the lingual surface. Teeth were then randomly divided into 2 groups. Group 1, which served as the control group, was restored as follows: group 1a, facial surface with PQ1 single-bottle bonding system plus TPH resin composite; group 1b, lingual surface with Prime & Bond NT single-bottle bonding system plus TPH. Group 2 was restored as follows: group 2a, facial surface with PQ1 plus Dyractflow compomer material; group 2b, lingual surface with Prime & Bond NT plus Dyractflow. After 24 hours of storage in water and subsequent thermocycling, each specimen was immersed in 0.2% basic fuchsin dye for 24 hours. The teeth were sectioned longitudinally and horizontally, and dye penetration at enamel and cementum margins was viewed at x30 magnification by 2 independently calibrated evaluators. Specimens were evaluated as either having leaked or not having leaked. RESULTS: No statistically significant differences in microleakage were noted between group 1 and group 2 specimens. CONCLUSION: Both single-bottle bonding systems, PQ1 and Prime & Bond NT, demonstrated equal effectiveness in reducing microleakage beneath compomer and composite restorations

PURPOSE: To examine and evaluate the topographies of Vita Mark II and Dicor MGC surfaces by SEM after simulating the common clinical procedures. MATERIALS AND METHODS: Twelve (12) samples of Dicor MGC and 12 samples of Vita Mark II were milled on a Cerec, a computer-controlled machine. Three cut surfaces were observed and photographed using a scanning electron microscope following standardized milling, etching and polishing procedures. RESULTS: The surface topographies of the ceramic restorative materials showed distinctly different characteristics. Dicor MGC showed definite shaped crystals after etching. The surface characteristics of etched Dicor MGC were different than etched Vita Mark II, which exhibited large trabeculations. The occlusal and proximal surfaces, which were not etched but polished, displayed large vacuoles with Vita Mark II while smaller vacuoles were seen in the fused crystals of Dicor MGC

The aim of this study was to evaluate the in vitro microleakage of a condensable composite resin recommended for Class II restorations with and without a flowable composite resin as a liner. There were statistically significant differences between all groups and between individual groups (p < 0.05). The results showed significantly less microleakage in teeth restored with flowable composite resin underneath a condensable composite resin