Cutting effectiveness of carbide burs following multiple steam autoclaving cycles.

New carbide burs that are placed on a bur block can be subjected to multiple steam autoclaving cycles prior to their first use. The decision to discard a bur before or during cavity preparation is a subjective one based on operator expectations and experience. This study examined the durability of carbide burs after multiple autoclaving cycles by judging not only their initial sharpness but also their ability to maintain sharpness throughout a cavity preparation. Five experienced operators were given a set of No. 330 carbide burs that had been separated into five blind categories: those not autoclaved at all and those that had been autoclaved one, two, five, or 10 times. Each operator judged the cutting effectiveness of each bur by making an initial plunge cut through the enamel of a freshly extracted tooth. After the initial plunge cut, each operator used the same set of burs to complete an occlusal cavity preparation in molar models fabricated from composite restorative material. Each operator was asked to examine the burs for any visual deterioration and to rate the cutting ability of each bur. The burs were also examined for wear under a scanning electron microscope. Based on the results, this study concluded that up to 10 autoclaving cycles did not significantly affect the perception of either initial sharpness or the bur's effectiveness while completing the preparation.

Three-year clinical evaluation of a compomer and a resin composite as Class V filling materials.

The purpose of this study was to evaluate the placement of two restorative materials, including a compomer (F2000, 3M ESPE) and a resin composite (Silux Plus, 3M ESPE), in non-carious cervical lesions using a self-etching bonding agent (F2000 self-etching primer/adhesive) and a fifth generation bonding agent (Single Bond, 3M ESPE) and to evaluate and compare these restorations for marginal discoloration, secondary caries, anatomical form, retention, surface texture and marginal adaptation at baseline and annually for three years. F2000 and Silux Plus were used to restore the teeth with moderate-sized non-carious cervical lesions. F2000 was placed using two different bonding agents: F2000 self-etching primer/adhesive (F2000SE group) and Single Bond (F2000SB group); Silux Plus was placed as a control using Single Bond (SiluxSB group). Thirty restorations of each material/dentin adhesive combination were placed. All restorations were evaluated at baseline and annually for three years using a modified USPHS scale. At the end of the three-year recall, Silux Plus had significantly better surface texture than F2000 (p < 0.0001). In addition, marginal adaptation significantly worsened over time starting at one year, as compared with baseline, for all groups (p < 0.0001). When anatomic form was compared between F2000 and Silux Plus, the p-value was 0.085, demonstrating that F2000 was slightly better than Silux Plus. Likewise, when comparing marginal adaptation between the F2000SE and SiluxSB groups, the p-value was 0.064, demonstrating that F2000 with the self-etching primer had better margins than Silux Plus with Single Bond. No other differences were found among the groups.

Clinical evaluation of four Class 5 restorative materials: 3-year recall.

PURPOSE: To place four restorative materials, including two resin-based composites (Pertac III and Synergy), an improved resin-modified glass-ionomer (Fuji II LC Improved), and a compomer (Dyract AP), in Class 5 non-carious cervical lesions and to evaluate and compare those restorations for marginal discoloration, anatomic form, surface texture, secondary caries, retention, and marginal adaptation at baseline and annually for 3 years. METHODS: The tested materials were used to restore moderate-size Class 5 non-carious cervical lesions. All materials were used following the manufacturers' directions for etching, bonding, curing, and finishing. Thirty restorations of each material were placed. After rubber-dam isolation, a bevel was placed on the occlusal margin of all preparations except the Fuji II LC Improved, and all preparations were cleaned with pumice. Each restorative material was placed and cured in increments except Fuji II LC Improved. All restorations were evaluated at baseline, 6 months, 1, 2, and 3-year recalls using a modified USPHS scale. RESULTS: Analysis with Chi Square and Logit Analysis revealed that, at 3 years, Pertac III and Fuji II LC Improved were significantly rougher than all other materials. Pertac III had significantly poorer marginal adaptation than all other materials. All other comparisons were not significant. At 3-year recall, most restorations were satisfactory.