Influence of different endodontic sealers on bond strength of fiber posts to weakened roots after resin restoration.

OBJECTIVES: To assess the influence of different sealers used in root canal filling, in terms of bond strength (BS) to dentin, after restoration of weakened roots using resin composite (RC) and fiber posts. MATERIAL AND METHODS: Roots of 39 maxillary incisors were used. After root canal preparation, root dentin was flared to produce a space between fiber post and root canal walls. The root canals were randomly distributed into three groups (n = 13), according to the sealer used: Endofill, AH Plus, and Acroseal. After removing the filling material to a depth of 12 mm, the flared roots were adhesively restored using RC. Posts were cemented and, after 24 h, roots were sectioned transversely producing 1-mm-thick slices. The slices from 30 roots were used for push-out test, and failure modes were noted. The remaining slices were analyzed by scanning electron microscopy (SEM). RESULTS: Statistical analysis by 2-way ANOVA showed a significant difference among sealers (p = 0.001) and among root regions (p < 0.001). The BS mean of Endofill was lower and significantly different from the others. Overall, the coronal region presented higher BS mean values, followed by the middle and apical regions of the reinforced roots. The most frequent failure type was the adhesive failure between RC and dentin. SEM analysis showed the formation of a hybrid layer and many tags in the coronal and middle regions, while the apical region exhibited remnants of the endodontic sealers in all groups. CONCLUSIONS: AH Plus and Acroseal sealer groups presented similar results, and the Endofill sealer negatively affected the BS of fiber post to restored root dentin. CLINICAL RELEVANCE: Weakened dentin walls are often found in teeth undergoing endodontic treatment, so the sealer used must allow or at least not interfere the bonding between restorative materials and root dentin.

Planejamento em facetas de porcelana: parte 2: preparação dental, a chave do sucesso / Designing porcelain laminate veneers: part 2: tooth preparation, the key of success

O alto grau de estética alcançado com facetas de porcelana, não só pela característica óptica natural inicial, mas principalmente por se manter o efeito obtido ao longo dos anos, tornou-as indicadas em várias situações clínicas, entre as quais está a substituição de facetas de resina composta. Estudos clínicos e testes laboratoriais têm ajudado a comprovar que os laminados cerâmicos são uma excelente forma de restabelecer a estética e a função de dentes anteriores de forma conservadora, pois geralmente o preparo se restringe apenas à porção vestibular do esmalte. As etapas clínicas para a confecção de uma faceta de porcelana são apresentadas e discutidas, na tentativa de demonstrar as possibilidades dessa modalidade restauradora...

The high level of aesthetics achieved by the use of porcelain laminate veneers is explained not only by the initial natural optical features, but by the maintenance over the years. This has made porcelain veneers indicated in several clinical situations. Among these indications are replacing resin composite veneers. Clinical and laboratory tests have helped to show that the ceramic veneers are an excellent approach to conservatively restore aesthetics and function of anterior teeth because the preparation is only restricted to enamel in the labial aspect. Thus, the clinical steps for a porcelain veneer treatment will be presented and discussed in an attempt to demonstrate the possibilities of this restorative approach...

Bond strength and fracture analysis between resin cements and root canal dentin.

The aim of this research is to evaluate bond strength between translucent fibre posts (White Post DC, FGM or FRC Postec Plus, Ivoclar/Vivadent) and intraradicular dentin at three different levels (cervical, middle and apical) using a dual-cure (AllCem, FGM) or self-curing (Multilink, Ivoclar/Vivadent) resin cement. Also, the fracture type after push-out test was analysed under SEM. Thirty-two extracted single-root teeth were selected. After undergoing endodontic therapy, they were randomly divided into four groups according to their post type and resin cement. Root canals were etched using 37% phosphoric acid, and Excite DSC adhesive (Ivoclar/Vivadent) was applied in all groups. The root was sectioned to obtain nine 1-mm-thick slices (three per third: coronal, middle, apical). All slices were subjected to push-out tests. Data were analysed using two-way anova. The mean bond strengths vary from 6.6 (4.6) MPa [apical] to 11.9 (5.9) MPa [cervical]. There were no significant differences between groups. Pearson χ(2)-test revealed significant differences in fracture types for all groups (P < 0.0001). The apical third had the lowest bond strengths and it was also shown to be the most critical region for luting fibre posts.

Clinical evaluation of 4% hydrogen peroxide bleaching in mandibular teeth

Introduction: Bleaching agents have been constantly introduced into market; however, the efficacy of new hydrogen peroxides still needs to be evaluated. Objective: The aim of this study was to evaluate in vivo the effectiveness of 4% hydrogen peroxide bleaching agent in color change, bleaching maintenance, tooth sensitivity, and patients' satisfaction. Material and methods: Forty subjects were selected, lower bleaching trays were constructed, and the patients were instructed to apply 4% hydrogen peroxide bleaching agent at home. Shade measurements of the mandibular anterior teeth were carried out with a spectrophotometer and Vita Classical shade guide (VITA) at the following moments: baseline, 14 days, after patients' satisfaction, and after 90 days. In addition, tooth sensitivity was evaluated using a visual analogue scale (VAS) at the first 14 days. Shade measurements were submitted to repeated measures ANOVA with Bonferroni adjustment and level of significance set at 5%. Results: Statistically significant differences were found for mandibular tooth shade after at-home bleaching (p < 0.001). After 14 days of bleaching, 90% of the subjects were not pleased with the achieved bleaching; however, after 27 days most of the patients reported to be satisfied. Tooth sensitivity was reported to range from 1.01 in a scale from 0-10. Conclusion: At-home bleaching using 4% hydrogen peroxide is effective in lower teeth with reduced tooth sensitivity.

Planejamento em facetas de porcelana. Parte 1: reforço do remanescente dental / Treatment planning using porcelain laminate veneers. Part 1: reinforcing the tooth remnant

O desenvolvimento da odontologia adesiva, associado à capacidade de condicionar-se a cerâmica e assim obter alta união aos tecidos dentais, tornou possível restaurar dentes anteriores esteticamente comprometidos, por meio de laminados cerâmicos. A restauração de dentes tratados endodonticamente é um procedimento complexo, que se torna mais complexo ainda, quando se seleciona a cimentação adesiva de pinos intra-radiculares. Este artigo, que é a primeira parte de dois trabalhos, apresenta um relato de caso do restabelecimento da resistência do remanescente dental enfraquecido, para dar condições de realização de faceta de porcelana no incisivo central superior.

The achievements in adhesive dentistry associated to surface treatment of ceramics (e.g. etching and signalization) to obtain high bond strengths to dental tissue make possible to restores anterior teeth with porcelain laminates veneers. Restoring endodontically treated teeth is a complex procedure, especially when fiber post cementation procedure is selected. This article is the first part of two that show a case report where dental tissue remaining was reinforced to make possible planning a laminate veneer on upper central incisor.

Clinical performance of vital bleaching techniques.

This study compared the clinical outcome of bleaching techniques in vital teeth. After IRB approval and informed consent, 90 subjects were selected based on the shade of their anterior teeth (A2 or darker, Vita Classic shade guide). Subjects were assigned to three treatment groups in a split-mouth study design: Group I: HB (at-home bleaching with 10% carbamide peroxide for two weeks) vs OBL (in-office bleaching with 35% hydrogen peroxide, two sessions, two-week intervals, with light irradiation); Group II: OB (in-office bleaching without light irradiation) vs OBL; Group III: HB vs combination (one session plus HB). Color change and color rebound (deltaE) were measured for a 16-week period. Color measurements were carried out with both a spectrophotometer and a shade guide at baseline, 1, 2, 4, 8 and 16 weeks. Tooth sensitivity was evaluated using a VAS scale for 15 days. Both the Student's t-test and Tukey-Kramer test were used to analyze the results (p < 0.05). After one week, one session of OBL followed by HB resulted in lower color values, compared with the other bleaching methods. Group III resulted in the least shade values at one-week evaluation, when compared with the other bleaching methods. After two weeks, HE alone resulted in similar color changes as OB, OBL and OBL+HB. The use of light irradiation did not improve bleaching efficacy (OB = OBL). OBL and OB resulted in higher sensitivity rates than HB.