The efficacy of ProTaper Universal rotary retreatment instrumentation to remove single gutta-percha cones cemented with several endodontic sealers.

AIM: To evaluate residual root filling material following removal of three newly developed root canal sealers used with a matched-taper single-cone root filling technique and to compare the efficacy of ProTaper Universal rotary retreatment instruments with that of a conventional manual technique. METHODOLOGY: The canals of 120 palatal roots in maxillary molar teeth were instrumented with EndoWave nickel-titanium rotary instruments and filled using Hybrid Root SEAL, EndoSequence BC Sealer, Activ GP system or AH Plus with matched-taper single gutta-percha cones. The root fillings were then removed with ProTaper Universal retreatment rotary instruments or a manual technique. Buccolingual and proximal digital radiographs of the roots were exposed to determine the area of remaining filling material in the coronal, middle and apical thirds. The area percentages of remaining filling material in each third and total canal area were calculated. Data were analysed statistically with Kruskal-Wallis and Mann-Whitney U-tests. The level of significance was set at P<0.05. RESULTS: Irrespective of the sealer type and retreatment technique, filling material could not be removed completely from the root canals. Significantly, more remaining filling material was observed in the apical third (P<0.05). When comparing the sealers, the only significant difference was detected between AH Plus/manual and Activ GP/manual groups with respect to residual material in the total canal area (P<0.05). There were no significant differences between manual and ProTaper groups. CONCLUSIONS: When using gross radiographic criteria, the Activ GP was more effectively removed from root canals than AH Plus with hand instrumentation. Hybrid Root SEAL, EndoSequence BC Sealer and AH Plus were removed to a similar extent. ProTaper Universal retreatment instruments were as safe and effective as hand instruments in reaching the working length.

Cytotoxicity of 5 endodontic sealers on L929 cell line and human dental pulp cells.

AIM: To investigate the cytotoxicity of five root canal sealers on L929 mouse fibroblasts and primary human dental pulp cells. METHODOLOGY: Cylindrical specimens of AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), RoekoSeal (Coltène Whaledent, Langenau, Germany), EndoREZ (Ultradent Products Inc., South Jordan, UT, USA), Epiphany (Pentron Clinical Technologies, LLCC, Wallingford, CT, USA) and Activ GP (Brasseller Inc., USA, Savannah, GA, USA) were kept at 37 °C in a humidified atmosphere of 5% CO(2) for thrice the length of the setting time given by the manufacturer. Extraction of specimens was performed after setting in cell growth medium for 1, 4 and 7 days. Undiluted, 50% and 25% diluted eluates were incubated with cultured cells for 24 and 72 h. Cytotoxicity was assessed using MTS colorimetric bioassay. Kruskal-Wallis test and post hoc Dunn's multiple comparison test were used to compare the sealers and diluted/undiluted eluates in terms of cell viability (% of control). Friedman test and post hoc Dunn's multiple comparison test were performed to compare extraction periods. Wilcoxon test was utilized in comparing 24- and 72-h readings. RESULTS: Undiluted 1-day eluate of Activ GP was significantly more cytotoxic than all other sealers (P < 0.0001). Undiluted 4- and 7-day eluates of Epiphany and Activ GP were significantly more cytotoxic than the other three sealers (P < 0.0001). Diluted eluates of Activ GP and Epiphany were generally less toxic than the undiluted ones. The cytotoxicity of Epiphany significantly increased as the extraction period increased (P < 0.0001). Epiphany became more toxic with time of exposure to cells. No or minimal cytotoxicity was observed with RoekoSeal, AH Plus and EndoREZ. CONCLUSIONS: The sealers exhibited varying degrees of cytotoxicity dependent on their chemical composition.

Tetracycline HCl solution as a root canal irrigant.

The effect of tetracycline hydrochloride as an endodontic irrigant on smear layer removal was examined by scanning electron microscopy and compared with bidistilled water, 2.5% sodium hypochlorite (NaOCl), and 50% citric acid in 20 extracted teeth. Five teeth, as a control, were irrigated with bidistilled water only in group 1. All the other groups were irrigated with NaOCI during instrumentation. The final rinses were NaOCl in group 2, citric acid in group 3, and 1% tetracycline hydrochloride in group 4. Scanning electron microscopic results and statistical analysis revealed that bidistilled water and NaOCl were ineffective in removing the smear layer, whereas citric acid and tetracycline hydrochloride were significantly more effective (p < 0.001). No statistically significant difference was detected between tetracycline hydrochloride and citric acid (p > 0.05). However tetracycline hydrochloride demineralized less peritubular dentin.

Cytotoxic and mutagenic potencies of various root canal filling materials in eukaryotic and prokaryotic cells in vitro.

Cytotoxic and mutagenic effects of root canal filling cements of various chemical composition were determined in vitro. Materials set for 24 h and 1 wk were eluted for 24 h in cell culture medium (cytotoxicity testing) and dimethyl sulfoxide or physiological saline (mutagenicity testing). The differences between cytotoxic potencies of eluates of the endodontic materials on L-929 cells were quantified colorimetrically (MTT test). Eluates of Traitement SPAD were about 5- to 30-fold more toxic than silver-free AH26, Tubli-Seal, CRCS, and Endomethsone N. The rank order of the toxic effects depended on the setting time of mixed materials. Dimethyl sulfoxide and saline eluates of Traitement SPAD, Tubli-Seal, Endomethasone N, CRCS, and Ketac-Endo were not mutagenic in the Ames test. Both eluates of silver-free AH26 set for 24 h were weakly mutagenic in Salmonella typhimurium TA100. Weak mutagenicity of saline eluates of the material was also observed in TA97a and TA102. These results point to the possibility that mixed silver-free AH26 might contain small amounts of two mutagenic substances: bisphenol A diglycidyl ether and formaldehyde.

Efficacy of hyaluronic acid spray on swelling, pain, and trismus after surgical extraction of impacted mandibular third molars.

The aim of this study was compare the efficacies of two oral sprays in reducing swelling, pain, and trismus after the extraction of impacted mandibular third molars. This prospective double-blind, randomized, crossover clinical trial included 34 patients with bilateral symmetrically impacted mandibular third molars of similar surgical difficulty. Hyaluronic acid or benzydamine hydrochloride spray was applied (two pumps) to the extraction area, three times daily for 7 days. Swelling was evaluated using a tape measure method, pain with a visual analogue scale (VAS), and trismus by measuring the maximum inter-incisal opening. Assessments were made on the day of surgery and on days 2 and 7 after surgery. Statistically significant differences were detected for the swelling and trismus values between the two treatment groups on the second postoperative day (P=0.002 and P=0.03, respectively). However, there was no statistically significant difference in VAS scores between the two groups. The administration of hyaluronic acid spray was more effective than benzydamine hydrochloride spray in reducing swelling and trismus. Although no evidence of a reduction in pain levels was detected, hyaluronic acid appears to offer a beneficial effect in the management of swelling and trismus during the immediate postoperative period following impacted third molar surgery.

Incidence of patent furcal accessory canals in permanent molars of a Turkish population.

AIM: To determine the incidence of patent furcal accessory canals in permanent molars of a Turkish population. METHODOLOGY: Two-hundred extracted teeth consisting of 50 maxillary first molars, 50 maxillary second molars, 50 mandibular first molars and 50 mandibular second molars from Turkish patients attending the Oral Surgery Department of the Faculty of Dentistry, Istanbul University, Istanbul, Turkey, were included in the study. After preparation of access cavities and removal of pulp tissue, the teeth were stored in 5.25% sodium hypochlorite for 1 h. Following double-sealing of the access cavities, all tooth surfaces except the furcation regions were covered with nail varnish. The teeth were stored in 0.5% basic fuchsin for 1 week. The teeth were sectioned at the cemento-enamel junction and the presence of patent furcal canals was established by examining the pulp chamber floor with a stereomicroscope (10x) to determine staining. RESULTS: Patent furcal accessory canals were detected in 24% of maxillary first molars, 16% of maxillary second molars, 24% of mandibular first molars, and 20% of mandibular second molars. No statistically significant differences were found between the tooth types. CONCLUSIONS: In a Turkish population, the incidence of patent furcal accessory canals on the pulp chamber floor of maxillary and mandibular first and second molars ranged between 16 and 24%.

Comparison of four different suture materials in soft tissues of rats.

OBJECTIVES: The purpose of this in vivo study was to histopathologically evaluate the inflammatory reaction incited by Vicryl in rats and compare this material with various suture materials that are widely used in the clinic. SUBJECTS AND METHODS: Four different suture materials, catgut, silk, polypropylene, and Vicryl were used in soft tissues of 32 Sprague-Dawley rats. Incisions performed were sutured by a standard technique. Eight rats were killed at the first, third, fifth, and seventh days. Histopathological evaluation of the en bloc samples was performed by determining the density of seven cell-types. A numerical grading from one to three was used. The data were statistically analysed by Kruskal-Wallis one way ANOVA and Dunn's tests. RESULTS: Vicryl has produced the mildest tissue reaction among the test materials at all experimental periods (P<0.05). Total cell number value in Vicryl group was found to be significantly lower than the one in catgut group (P<0.05). CONCLUSION: Under the conditions of this study, the results demonstrated that Vicryl as a suture material produced the mildest tissue reaction during early healing period.