Is a Single Preliminary Session of In-office Bleaching Beneficial for the Effectiveness of At-home Tooth Bleaching? A Randomized Controlled Clinical Trial.

OBJECTIVES: To evaluate the effect of combining in-office with at-home bleaching procedures in terms of the time required to obtain satisfactory tooth color, final color changes, and tooth sensitivity (TS) reported by patients. METHODS AND MATERIALS: Twenty-six patients enrolled in this study used 10% carbamide peroxide in a bleaching tray for 1 h/d until satisfactory tooth color was obtained. One-half of the participants underwent a preliminary session of in-office tooth bleaching with 35% hydrogen peroxide for 45 minutes. The time in days for the patients to obtain satisfactory tooth color by at-home bleaching procedures was recorded. The color change of the maxillary canines was assessed using the Vita Bleachedguide 3D Master scale and a spectrophotometer at 1 week and after the end of bleaching procedures. Participants' satisfaction with their smile was recorded using a visual analog scale, and TS was determined throughout the entire treatment. Data were analyzed by t-test, Mann-Whitney test, or Fisher exact test (α=0.05). RESULTS: The combined protocol reduced (by an average of 3.7 days) the time required to obtain satisfactory tooth color but increased the risk and level of TS. No difference in the final tooth color change (around 5.0 shade guide units; ΔE=11.6-14.9), or the level of patients' satisfaction with their smile, was observed. CONCLUSIONS: A preliminary session of in-office bleaching reduced the time necessary to obtain satisfactory tooth color with at-home bleaching but increased the risk and level of TS.

Bonding of Adhesive Luting Agents to Caries-affected Dentin Induced by a Microcosm Biofilm Model.

OBJECTIVES: To evaluate the bond strength of adhesive luting agents applied to caries-affected dentin (CAD). METHODS: Thirty-six noncarious human third molars were abraded to expose an occlusal dentin surface. Caries lesions were induced in half of the samples using a microcosm biofilm model. Biofilm was cultivated under an anaerobic atmosphere for 14 days in a medium enriched with mucin. The same medium containing 1% sucrose was alternated for 4 hours per day. Cylinders of resin cement (RelyX ARC, RelyX U200, or BisCem) were built up over the dentin substrate and submitted to shear bond load. The samples were then longitudinally sectioned. The hardness and elastic modulus of dentin were measured at different depths from the occlusal surface. A three-dimensional finite element simulation was performed to analyze the residual stress distribution during the shear bond strength test. Bond strength data were analyzed by two-way analysis of variance (ANOVA) and hardness and elastic modulus by split-plot ANOVA. Multiple comparisons were performed with the SNK test (α=0.05). RESULTS: For all cements, the highest bond strengths were observed in sound dentin. Relyx ARC bond strength was similar to that of RelyX U200 for both substrates; BisCem had the lowest values. CAD had lower hardness (above a depth of 100 µm) and elastic modulus (above a depth of 150 µm) values than sound dentin. Stress distribution during the bond strength test was similar under all experimental conditions. CONCLUSION: Impairment of the mechanical properties of dentin promoted by carious lesions reduced the bond strength of adhesive luting agents.

Knowledge regarding emergency management of avulsed teeth among elementary school teachers in Jaboatão dos Guararapes, Pernambuco, Brazil.

OBJECTIVE: The purpose of the present study was to assess the knowledge regarding emergency management of tooth avulsion among elementary schoolteachers in the city of Jaboatão dos Guararapes, Pernambuco, Brazil. MATERIALS AND METHODS: A total of 338 teachers answered a questionnaire with items on emergency procedures following tooth avulsion. RESULTS: The majority of teachers (89.1%) had received no previous orientation regarding management of dental trauma and 81.4% had not witnessed an accident in which tooth avulsion had occurred. If an avulsed tooth had fallen to the ground, 84.3% of the teachers said they would pick it up, and 67.8% of them stated that they would clean it with water or some other liquid. A total of 33.1% said that they would take the student with the tooth in hand to a dental office. Of the respondents 88.5% would seek professional help immediately; 85.2% stated they would be unable to reimplant the avulsed tooth; and 39.3% would store the tooth in water. CONCLUSIONS: A lack of technical information was observed among teachers regarding management of tooth avulsion. Educational campaigns at schools are necessary to modify the behavior of the teachers with regard to management of tooth avulsion. Further studies should be carried out for the assessment of teachers who have participated in educational campaigns to make the treatment of dental trauma a matter of public interest.