Osvaldo Zmener

Reaction of Rat Subcutaneous Connective Tissue to a Mineral Trioxide Aggregate–based and a Zinc Oxide and Eugenol Sealer

INTRODUCTION The purpose of this study was to evaluate the subcutaneous connective tissue reaction in rats to a mineral trioxide aggregate (MTA)-based endodontic sealer Fillapex (Angelus, Londrina, PR, Brazil) and compare it with Grossman sealer (Farmadental, Buenos Aires, Argentina). METHODS Sterile medical-grade silicone tubes containing the test materials were implanted in 24 Wistar rats. After 10, 30, and 90 days, the animals (n = 8 per period) were euthanized, and the implants along with their surrounding tissues were dissected, fixed, and processed for histologic evaluation. A 4-category evaluation system was used to evaluate the microscopic observations. The tissue response on the lateral walls of the silicone tubes was used as the negative control. The data were analyzed for statistical significance using the Wilcoxon signed rank, Kruskal-Wallis, and Dunn tests. RESULTS Fillapex showed a severe tissue reaction for all 3 observation periods. Grossman sealer showed similar features after 10 and 30 days, but the reaction decreased slightly after 90 days. In contrast, the negative controls did not show adverse reactions in any sample of the 3 time periods. After 10 and 30 days, no statistically significant differences were found between Fillapex and Grossman sealer (P > .05); however, the difference was significant after 90 days (P < .05). For all experimental periods, there were statistically significant differences between both Fillapex and Grossman sealer and the negative controls (P < .05). CONCLUSIONS It was concluded that both MTA-Fillapex and Grossman sealer remained toxic to subcutaneous tissues in rats after 90 days.

Efficacy of the NaviTip FX Irrigation Needle in Removing Post Instrumentation Canal Smear Layer and Debris in Curved Root Canals

INTRODUCTION This study evaluated the effectiveness of the NaviTip FX (Ultradent Products Inc, South Jordan, UT), a 30-gauge brush-covered irrigation needle, in removing debris and smear layer in vitro. METHODS Forty mesio-buccal maxillary and mandibular first molar root canals with 20 degrees to 30 degrees curved roots were randomly divided into four groups (n = 10). The irrigation protocol after cleaning and shaping was as follows: NaOCl/EDTA/nonbrushing (NaED) group: passive use with 5.25% NaOCl followed by 17% EDTA and saline; EDTA/brushing (EDBr) group: passive use with 5.25% NaOCl followed by left and right manual rotary up and down brushing using 17% EDTA and a saline rinse; EDTA/FileEze (Ultradent Products Inc)/brushing (EDFEBr) group: same as EDBr, however, with FileEze; and control group (CG): a standard 30-gauge NaviTip irrigation needle used passively. The roots were split longitudinally and the canals examined in a scanning electron microscope. Debris and smear layer were recorded at 1, 5, and 10 mm from the working length (WL) using a three-step scoring scale and 300-mum square grid. Mean scores were calculated and statistically analyzed (p < 0.05) between and within groups. RESULTS Comparison between groups revealed that at all evaluation levels EDBr and EDFEBr groups were significantly cleaner (p < 0.05) than NaED and CG, with no significant difference between them. Comparison within groups did not show significant differences (p > 0.05). All groups showed significantly better smear layer removal (p < 0.05) at 5 and 10 mm from the WL. The EDBr group exhibited no significant differences (p > 0.05) between the three evaluation levels. CONCLUSION In moderately curved root canals, a NaviTip FX used with 5.25% NaOCL and 17% EDTA solution with manual brushing as well as the same method augmented by FileEze was the most effective cleaning protocol.

Resin Materials for Root Canal Obturation

With the appearance of more in vivo and ex vivo publications, methacrylate based resin sealers are becoming more popular in endodontics. Their ease of use and favorable clinical performance offer an attractive alternative to conventional endodontics. This article reviews the development of resin-based sealers and biocompatibility tests. The many, mostly opposing views are analyzed to put what has been published thus far in perspective. A critical analysis of the facts leads to the consensus that methacrylate based resin sealers are here to stay and offer a suitable alternative to conventional endodontic treatment.

Clinical and radiographic evaluation of a resin-based root canal sealer: an eight-year update.

INTRODUCTION This retrospective clinical and radiographic study evaluated the 8-year outcome of one-visit endodontic treatment of root canals filled with gutta-percha and a methacrylate resin-based sealer (EndoREZ). METHODS From an initial sample size of 180 patients, subsequently 145 and 120 patients were evaluated after 14-18 months and 5 years, respectively. Of the remaining patient pool of 120 patients evaluated after 5 years, 112 patients with 212 root canals responded to the 8-year recall. The outcome of treatments was assessed on the basis of clinical and radiographic criteria. Endodontic success was rated on the basis of absence of clinical symptoms, the presence of a normal or slightly widened periodontal ligament space, and absence or substantial reduction in size of preexisting periradicular radiolucencies. Teeth that did not meet these criteria were considered endodontic failures. RESULTS The root canals had been adequately filled to the working length in 90 teeth (80.35%) and were short in 19 instances (16.96%). None of the roots showing apical extrusion of the sealer immediately postoperatively had radiographic evidence of the sealer in the periradicular tissues after 8 years. At recall, all patients were comfortable and free of clinical symptoms. A life table analysis showed a cumulative probability of success of 86.5% after 8 years, with a 95% confidence interval of 79.0-92.0. CONCLUSIONS The results of this retrospective clinical and radiographic study suggest that the tested methacrylate resin-based sealer used in conjunction with gutta-percha cones performed similarly to conventional endodontic sealers during a period of up to 8 years.

Subcutaneous Connective Tissue Reaction to Methacrylate Resin–based and Zinc Oxide and Eugenol Sealers

INTRODUCTION An evaluation was made of the connective tissue reaction in rats after subcutaneous implantation of methacrylate resin-based sealers (EndoREZ [Ultradent Products, Inc, South Jordan, UT] with a polymerization accelerator and RealSeal [Sybron Dental Specialties, Orange, CA]) and Pulp Canal Sealer (Sybron Dental Specialties), a zinc oxide and eugenol-based sealer used as the control. METHODS Silicone tubes containing the test materials were implanted in 24 Wistar rats. Solid silicone rods of the same size served as the negative controls. After 10, 30, and 90 days, the animals (n = 8 per period) were euthanized and the implants with surrounding tissues dissected and processed for routine histological evaluation. A four-category evaluation system was used to measure and record the microscopic observations according to the thickness of a fibrous capsule, the vascular changes, and the various types of inflammatory cells. RESULTS Initially, a severe inflammatory reaction was observed of the soft tissues in direct contact with both EndoREZ/Accelerator and Real Seal. The severity decreased over time and was resolved at the end of the experiment. Pulp Canal Sealer showed a severe tissue reaction for all observation periods. The negative controls showed an initial mild to moderate inflammatory reaction. After 30 days, healthy fibrous connective tissue was observed, which increased over time. After 10 days, no statistically significant differences between the experimental groups were observed. After 90 days, EndoREZ and RealSeal were statistically significantly less toxic than Pulp Canal Sealer (p > 0.05). CONCLUSIONS After 90 days, both methacrylate resin-based sealers were considered biologically acceptable when implanted in subcutaneous connective tissues of the rat. Pulp Canal Sealer remained toxic for the duration of the study.

Cleaning Efficacy Using Two Engine-driven Systems versus Manual Instrumentation in Curved Root Canals: A Scanning Electron Microscopic Study

INTRODUCTION This ex vivo study evaluated the cleanliness of curved root canal walls after chemomechanical instrumentation using two automated systems versus manual instrumentation while using a standardized irrigation protocol. METHODS Thirty mesial root canals of extracted human first and second mandibular molars were prepared with the TiLOS hybrid engine-driven instrumentation system (Ultradent Products Inc, South Jordan, UT) (n = 10), ProTaper engine-driven file series (n = 10), and manual instrumentation (n = 10). Irrigation was performed using alternately 5.25% sodium hypochlorite and 17% EDTA followed by rinsing with distilled water. After the roots were split longitudinally, the presence of debris and/or smear layer was visualized using serial scanning electron microscopic digital photomicrographs taken at 1, 5, and 10 mm from the working length. Mean scores for debris and the smear layer were calculated and statistically analyzed for significance (P < .05) between groups using the Kruskal-Wallis nonparametric analysis of variance and Dunn tests. The data obtained at each evaluation level for each group were analyzed using the Friedman and Tukey multiple comparison tests. RESULTS No significant differences (P > .05) were found between TiLOS and ProTaper (Dentsply/Tulsa Dental, Tulsa, OK) groups, whereas both performed significantly better than the manual instrumentation group. CONCLUSIONS Engine-driven TiLOS and ProTaper instrumentation systems combined with a standardized irrigation protocol produced cleaner root canal walls than the manual instrumentation technique although complete cleanliness was not achieved.

Frequency and distribution of teeth requiring endodontic therapy in an Argentine population attending a specialty clinic in endodontics

OBJECTIVES To determine the frequency and distribution of 975 teeth in need of endodontic treatment in an Argentine patient pool and to compare the results with previously published surveys. METHODS Of the 975 teeth from 860 individuals (age range 7-86 years) were endodontically treated during 2007 by postgraduate students enrolled in a specialisation programme in Endodontics. All patients were examined clinically and radiographically. For each case, information was collected in a questionnaire including location of the affected tooth, age and gender and reasons for endodontic treatment. Data were analysed by the Student t-test, the Fisher exact test, and the chi-square test with a significance of P < 0.05. RESULTS Of the 975 treated teeth, 543 (55.69%) were maxillary and 432 (44.30%) mandibular teeth. 635 (65.13%) were from females and 340 (34.87%) from males. Significant differences were found between the maxillary and mandibular arch (P = 0.01). Molars and premolars required significantly more frequent endodontic treatment than canines and incisors (P < 0.001). The most frequently treated tooth was the mandibular right first molar (9.12%) followed by the mandibular left first molar (7.07%). The most frequently diagnosed pathosis was irreversible pulpitis (36.00%), pulp necrosis (30.80%), apical periodontitis or the presence of easily discernible periapical radiolucent areas (27.20%). Caries (59.18%) and failure of previous endodontic treatment (26.97%) were responsible for most of the affected teeth. CONCLUSIONS   Comparison with previous surveys revealed that more females than males received endodontic treatment and that mostly molars and premolars were in need of endodontic treatment. The high number of root filled teeth requiring retreatment is in agreement with a pattern similar to that observed in other countries and supports the need for more specialists in endodontics in the Republic of Argentina.