The influence of previous nonsurgical re-treatment on the outcome of endodontic surgery

AIM: The aim of this study was to evaluate retrospectively if the outcome of periradicular surgery at four year follow-up can be affected by a previous orthograde re-treatment. METHODS: Eighty-one patients with 118 endodontically treated teeth who underwent surgical retreatment were divided in three groups. In group OA endodontic re-treatment was feasible and was attempted but, owing to the persistence of clinical symptoms and radiographic lesion, apical surgery was performed 4.8 \ub1 3.5 months later. In group OF endodontic re-treatment was feasible but was not performed, with subsequent apical surgery. In group ONF endodontic re-treatment was unfeasible, and apical surgery was performed. The treatment outcome was assessed four years postsurgery according to clinical and radiographic criteria. RESULTS: Seventy-six patients (112 teeth) could be evaluated at four years. In the ONF group five anterior maxillary teeth, belonging to three female patients, failed to heal. Three failures in three patients occurred in the OF group. No failure was recorded in the OA group. Three teeth in three patients were classified as uncertain healing in each group. The outcome of group OA resulted significantly better than the other treatment groups for both tooth-based and patient-based analysis. No significant effect was found as related to jaw, tooth type, presence of a post. A significant relation was found with gender (P=0.04). A negative correlation was found between outcome and age (Pearson's coefficient=-0.09), suggesting that the probability of failure increases with age. CONCLUSION: Orthograde re-treatment prior to apical surgery could be considered a valid alternative to tooth extraction and not an over-treatment

Comparative evaluation of the shaping ability of two different nickel-titanium rotary files in curved root canals of extracted human molar teeth

The aim of the present study was to compare the shaping ability of two different nickel-titanium rotary files in the curved root canals of extracted human molar teeth.Thirty root canals of 17 extracted human molars teeth were randomly assigned to two experimental groups (n = 15): ProTaper Next and ProTaper Universal (PTU), on the basis of the rotary files system used. The final size of all apical foramina was 0.25 mm in diameter. Standardized digital radiographs were taken before and after instrumentation in both clinical and proximal views, with a size 10 K-file inserted into the canal for the determination of the angle of curvature and apical transportation. Preparation time and fractured or deformed instruments were also recorded. The unpaired Student's t-test was used to compare results. There was no significant difference between the two instruments with respect to canal straightening and apical transportation before and after instrumentation (P > 0.05). The use of both instruments resulted in a significant reduction in the angle of curvature after instrumentation (P < 0.05). Instrumentation time was significantly greater for PTU (P < 0.05). The ProTaper Universal and ProTaper Next systems performed similarly with regard to the straightening of curved root canals and apical transportation. ProTaper Next was significantly faster than ProTaper Universal

Avantages et limites des instruments en nickel-titane pour la preparation canalaire endodontique. Revue de la litterature recente

In recent years, an important innovation in the field of dentistry has been the introduction of nickel-titanium alloy instruments. Superelasticity and shape memory are the main mechanical properties of this alloy which prompted its use in endodontics. Due to these characteristics, NiTi instruments have been demonstrated to preserve the original anatomy, the shape and position in space of the apical foramen. This literature review of mechanical properties of NiTi endodontic instruments aims to provide clinicians with a better understanding of their advantages and limits