Root Canal Shaping by Single-File Systems and Rotary Instruments: a Laboratory Study

Introduction: The aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. Methods and Materials: Mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25° and 35° and radii of curvature from 5 to 9 mm, were divided into three groups (n=40). In each group the canals were instrumented with either WaveOne (W), Reciproc(R) or ProTaper (P). The time required for canal shaping and the frequency of broken instruments were recorded. The standardized pre and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analyzed using the one-way analysis of variance (ANOVA) and post-hoc Tukey’s test. The level of significance was set at 0.05. Results: Both single-instrument systems reduced the canal preparation time by approximately 50% (P<0.05). No incidence of broken instruments from single-file systems was reported; however, two F2 instruments in the P group were broken (P<0.05). Reduction in WL and straightening of canal curvature was observed in all three systems with the highest scores belonging to P system (P<0.05). No case of blockage or perforation was found during shaping in any group. Conclusion: Single-file systems shaped curved canals with substantial saving in time and a significant decrease in incidence of instrument separation, change in WL, and straightening of canal curvature

One-Year Clinical Evaluation of the Bonding Effectiveness of a One-Step, Self-Etch Adhesive in Noncarious Cervical Lesion Therapy

This study evaluated the one-year clinical performance of a one-step, self-etch adhesive (Optibond All-in-One, Kerr, CA, USA) combined with a composite (Herculite XRV Ultra, Kerr Hawe, CA, USA) to restore NCCLs with or without prior acid etching. Restorations performed by the same practitioner were evaluated at baseline and after 3, 6, and 12 months using modified USPHS criteria. At 6 months, the recall rate was 100%. The retention rate was 84.2% for restorations with prior acid etching, but statistically significant differences were observed between baseline and 6 months. Without acid etching, the retention rate was 77%, and no statistically significant difference was noted between 3 and 6 months. Marginal integrity (93.7% with and 87.7% without acid etching) and discoloration (95.3% with and 92.9% without acid etching) were scored as Alpha or Bravo, with better results after acid etching. After one year, the recall rate was 58.06%. Loss of pulp vitality, postoperative sensitivity, or secondary caries were not observed. After one year retention rate was of 90.6% and 76.9% with and without acid conditioning. Optibond All-in-One performs at a satisfactory clinical performance level for restoration of NCCLs after 12 months especially after acid etching

Évaluation clinique à six mois d’un adhésif auto-mordançant dans le traitement des lésions cervicales non carieuses

Introduction : L’adhésion aux tissus dentaires est un sujet en permanente évolution tant pour le choix des matériaux que des protocoles proposés au praticien, rendant ainsi difficile sa réalisation en clinique. Il l’est d’autant plus pour les lésions cervicales non carieuses du fait de leur localisation et de la qualité du substrat. Objectif : Le but de ce travail était d’évaluer à six mois l’efficacité clinique d’un adhésif auto-mordançant dans le traitement de 150 lésions cervicales non carieuses. Méthode : Un total de 150 restaurations (76 avec mordançage et 74 sans mordançage) a été placé par un même opérateur chez 31 patients âgés de 24 à 73 ans. L’adhésif était appliqué selon les recommandations du fabricant suivi de l’application du composite Herculite® XRV Ultra (Kerr Hawe, USA). Les restaurations ont été évaluées à trois et six mois en utilisant les critères USPHS modifiés. Les données ont été statistiquement analysées en utilisant le logiciel SPSS 10.0. Résultats : Huit restaurations ont été perdues à six mois pour celles réalisées avec mordançage et onze pour celles effectuées sans mordançage. Neuf restaurations ont présenté une perte clinique de l’intégrité marginale. Une légère coloration marginale a été observée sur quatre restaurations (deux avec et deux sans mordançage). Il n’y pas de différence statistiquement significative. Conclusion : Selon le protocole clinique utilisé dans cette étude, les restaurations des lésions cervicales non carieuses réalisées avec ou sans mordançage ont un comportement clinique acceptable à six mois