Efficacy of root-end filling techniques using premixed putty type bioceramic cements: an ex vivo study.

OBJECTIVES: Currently, premixed putty-type bioceramic cements (PPBCs) have become popular materials for root-end fillings. This study investigated three root-end filling techniques using PPBCs and calcium silicate-based sealers including EDTA pretreatment. MATERIALS AND METHODS: Ninety root segments were prepared and standardized with an artificial fin and lateral canal, and assigned to three groups (n = 30). Root-end fillings were placed using BC-RRM Putty alone (Group PA), injection of BC sealer followed by BC-RRM Putty (Lid Technique: Group LT) or BC-RRM Putty with BC sealer coating (Deep putty packing technique: Group DP). Half of each group was pretreated with 17% EDTA. The radiographic images of the specimens were assessed by five graders and push-out bond strength tests were conducted. The data were analyzed with a general linear model including two-way ANOVA and chi-square test at a significance level of 5%. RESULTS: DP approach demonstrated significantly higher bond strength than LT (P < 0.05). However, there was no statistically significant difference in bond strength between PA and either DP or LT. EDTA pretreatment had no significant effect on push-out bond strength. Radiographically, for the main canal, PA and DP scored significantly higher than LT. In the fin, PA scored significantly higher than others (P < 0.05). CONCLUSION: Our study highlights variations in root-end filling techniques. Injecting a bulk of bioceramic sealer before the placement of PPBCs may reduce bond strength and radiopacity. The application of PPBCs alone or in the deep putty technique demonstrates potential for favorable outcomes. EDTA pretreatment did not enhance bond-strength. CLINICAL RELEVANCE: Careful selection and application of bioceramic materials and techniques in root-end fillings may influence the outcome of endodontic root-end surgery. When PPBCs and calcium silicate-based sealers are used together for root-end fillings, sealer followed by deep putty application may offer improved bond strength and radiographic fill compared to the lid technique.

In-office vital bleaching with adjunct light.

The use of light as an adjunct to in-office bleaching is a controversial topic in dentistry because of the equivocal outcomes of the research conducted in studies using light compared with no light treatment. The proper diagnosis and treatment planning of discolored teeth is of primary importance when managing the outcomes and setting expectations for patients undergoing in-office bleaching with supplemental light. Although no study is conclusive on all bleaching lights, research evidence provides guidelines for the responsible use of in-office bleaching lights in dentistry.

Veneer retention of preveneered primary stainless steel crowns after crimping.

PURPOSE: The purpose of this study was to determine if crimping the lingual aspect of commercially available, preveneered, anterior stainless steel primary crowns affects the fracture resistance of the veneer facings. METHODS: Twenty-six anterior NuSmile crowns (size A1) were divided into 2 groups: group 1 served as the control, and group 2 was manually crimped evenly on the lingual cervical portion. All crowns were cemented onto a screw-mounted resin core duplicated from a manually prepared Kilgore tooth and tested under compression. Recorded were fracture resistance, percent of veneer facing loss, and fracture to the gingival margin. Differences between the control and experimental groups were analyzed by independent t test and chi-square (alpha=0.05). RESULTS: The mean shear force required to fracture the veneers of the noncrimped crowns was 510.11 N (+/-79.66 SD), and 511.02 N (+/-62.37) for the crimped crowns. The mean percentage of veneer facing removed in the noncrimped crowns was 33% (+/-12.18), and 43% (+/-14.30) in the crimped crowns. No significant difference in shear strengths (P=.970) and in percentage of veneer loss (P=.063) was shown between crimped and noncrimped crowns. A mean of 8% of the noncrimped crowns and 23% of the crimped crowns had veneers fracturing to the gingival margin. The chi-square test showed no significant difference (P=.297). CONCLUSIONS: The veneer resistance to fracture for the crimped crowns was comparable to noncrimped crowns. The crimped crowns, however, were associated with greater veneer surface area loss.