Aline Carvalho Peixoto

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.

Immunohistochemical Analysis of Human Homologue of Drosophila Patched (PTCH) in Dental Follicles of Impacted Third Molars

Se investigo la inmunodeteccion de PTCH en los componentes epiteliales de los foliculos dentales asociados a terceros molares retenidos sin signos radiograficos y morfologicos de patologia. Fueron quirurgicamente extraidos de 56 pacientes 105 muestras de foliculos dentales asociadas a terceros molares retenidos con rizogenesis incompleta (entre el estadio de Nolla 6 y 9). La proliferacion de celulas epiteliales se detemino mediante inmunohistoquimica. El analisis estadistico se realizo mediante la prueba exacta de Fisher. De los 105 foliculos dentales recogidos, 3 fueron PTCH-positivos. Las muestras con metaplasia escamosa e hiperplasia epitelial tuvieron mayores tasas de positividad para PTCH, asi como aquellos con los restos de proliferacion del epitelio odontogenico. En conclusion, este estudio sugiere que las celulas odontogenicas del foliculo dental podrian estar proliferando durante la rizogenesis, mientras que la metaplasia escamosa e hiperplasia del epitelio y de restos epiteliales odontogenicos en proliferacion muestran el potencial de diferenciacion de los foliculos dentales.

Bilateral Bifid Mandibular Condyle: A Case Report

El proceso condilar bifido es una anomalia muy rara. Se diagnostica como un hallazgo accidental en una radiografia panoramica. Su etiologia y patogenia son desconocidas, aunque la teoria mas aceptada sugiere que el trauma esta en el origen de esta condicion. Este articulo presenta un nuevo caso de proceso condilar bifido bilateral en una mujer de 21 anos de edad con antecedentes de trauma en la infancia.

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient’s sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients’ perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.