Comparison of occlusal wear between bulk-fill and conventional flowable resin composites.

PURPOSE: To investigate the occlusal wear of bulk-fill and conventional flowable resin composites. METHODS: Four bulk-fill flowable resin composites: (1) Filtek Bulk Fill Flowable Restorative (FB); (2) G-ænial Bulk Injectable (GB); (3) SDR Flow+ (SD); and (4) Tetric EvoFlow Bulk Fill (TB), and four conventional flowable resin composites: (1) Clearfil Majesty IC (CM); (2) Filtek Supreme Ultra Flow (FF); (3) G-ænial Universal Flow (GF); and (4) Herculite XRV Ultra Flow (HF) were evaluated. Localized wear was simulated using 400,000 cycles in a Leinfelder-Suzuki (Alabama) device with a stainless-steel ball bearing antagonist. Volume loss and maximum depth of wear facets were measured using a Proscan 2100 noncontact profilometer in conjunction with analyzing software. Scanning electron microscopy observations were also conducted on the wear specimens. RESULTS: Simulated occlusal wear was significantly different (P< 0.05) among the materials tested. FF, GB and GF showed significantly less wear than the other tested resin composites. The rank order of volume loss and maximum depth was GF-GB-FF-FB-CM-HF-TB-SD. CLINICAL SIGNIFICANCE: Bulk-fill flowable resin composites showed a much wider range of wear properties than conventional flowable resin composites. Some composites of each type may be suitable for use in occlusal contact areas of posterior restorations, but care must be taken when selecting such a resin.

Laboratory evaluation of dentin tubule occlusion after use of dentifrices containing stannous fluoride.

The purpose of this study was to examine the effect of desensitizing dentifrices containing stannous fluoride (SnF2) on dentinal tubule occlusion. Two experimental dentifrices with the same ingredients but different SnF2 concentrations (Group II, 0.4% w/w; Group III, 0.454% w/w) were used; distilled water was used in the control group (Group I). Third molars were collected from Japanese and American dental patients. The crowns were removed and sectioned to obtain dentin discs, which were further cut into quarters. Thirty-six specimens each from Japanese and American patients were divided into three sets (n = 12 each) and assigned to each of the three treatment groups. The specimens were brushed for 10 s twice per day for 4 days. After treatment, the discs were observed by scanning electron microscopy, and the extent of dentinal tubule occlusion in the images was expressed on a five-point categorical scale. Group II and III specimens from Japanese and American patients showed greater dentinal tube occlusion than those from Group I, but the differences were not statistically significant. The present results suggest that both SnF2 concentrations mitigate dentin hypersensitivity, regardless of patient ethnicity.