Daniel Grana

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.

Rat subcutaneous tissue response to modified Portland Cement, a new mineral trioxide aggregate

The purpose of this study was compare the biocompatibility of modified Portland cement (CPM) and mineral trioxide aggregate (MTA) in a subcutaneous rat model. Twenty-four male Wistar rats were used. Three silicon tubes were placed on the dorsal subcutaneous tissue of each animal: one tube contained MTA, one tube contained CPM and the other was an empty tube. The rats were sacrificed in 3 groups of 8 animals at 7, 14 and 30 postoperative days, respectively. Tissue samples were fixed in 10% buffered formalin, embedded in paraffin, and serial sections were cut and stained with hematoxylin and eosin, Masson Trichrome and Lunas stain. At day 7, the empty tubes displayed a mild inflammatory infiltrate. In the CPM group, an inflammatory infiltrate was observed with some eosinophils and immature connective tissue. The MTA group showed a similar infiltrate without eosinophils and presence of abundant necrotic tissue and numerous multinucleate foreign body giant cells. At day 14, the chronic infiltrate with eosinophils persisted when in contact with CPM. In the MTA group, necrosis and distant giant cells could still be seen. At day 30, all 3 groups showed mature fibrous collagenous tissue. These findings indicate a different response to the materials evaluated in this study. Although, MTA and CPM induced a chronic inflammatory infiltrate, necrosis and multinucleated foreign body giant cells predominated in the MTA group, while in the CPM group numerous eosinophils were seen at all the observational periods.

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.

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.