Taurodontism can be defined as a change in tooth shape caused by the failure of Hertwig's epithelial sheath diaphragm to invaginate at the proper horizontal level. An enlarged pulp chamber, apical displacement of the pulpal floor, and no constriction at the level of the cemento-enamel junction are the characteristic features. Although permanent molar teeth are most commonly affected, this change can also be seen in both the permanent and deciduous dentition, unilaterally or bilaterally, and in any combination of teeth or quadrants. Whilst it appears most frequently as an isolated anomaly, its association with several syndromes and abnormalities has also been reported. Despite the clinical challenges, taurodontism has received little attention from clinicians. Because of the prevalence of taurodontism in modern dentitions and the critical need for its true diagnosis and management, this review addresses the etiology, clinical and radiographic features of taurodontism, its association with various syndromes and anomalies, as well as important considerations in various areas of expertise dental treatments of such teeth.

Background:Periapical lesions occur in response to chronic irritation in periapical tissue, generally resulting from an infected root canal. Specific etiological agents of induction, participating cell population and growth factors associated with maintenance and resolution of periapical lesions are incompletely understood. Among the cells found in periapical lesions, mast cells have been implicated in the inflammatory mechanism.Aim:Quantifications and the possible role played by mast cells in the periapical granuloma and radicular cyst. Hence, this study is to emphasize the presence (localization) and quantification of mast cells in periapical granuloma and radicular cyst.Materials and Methods:A total of 30 cases and out of which 15 of periapical granuloma and 15 radicular cyst, each along with the case details from the previously diagnosed cases in the department of oral pathology were selected for the study. The gender distribution showed male 8 (53.3%) and females 7 (46.7%) in periapical granuloma cases and male 10 (66.7%) and females 5 (33.3%) in radicular cyst cases. The statistical analysis used was unpaired t-test.Results:Mean mast cell count in periapical granuloma subepithelial and deeper connective tissue, was 12.40 (0.99%) and 7.13 (0.83%), respectively. The mean mast cell counts in subepithelial and deeper connective tissue of radicular cyst were 17.64 (1.59%) and 12.06 (1.33%) respectively, which was statistically significant. No statistical significant difference was noted among males and females.Conclusion:Mast cells were more in number in radicular cyst. Based on the concept that mast cells play a critical role in the induction of inflammation, it is logical to use therapeutic agents to alter mast cell function and secretion, to thwart inflammation at its earliest phases. These findings may suggest the possible role of mast cells in the pathogenesis of periapical lesions.

BACKGROUND The primary goal of endodontic retreatment is to take out the root filling completely to ensure that the canal is completely cleaned. Gutta percha removal using hand instruments is a time-consuming procedure and tedious for the operator. Therefore, various nickel titanium instruments have been introduced for the effective retrieval of gutta percha. This study was done to compare the efficacy of three different rotary systems compared with manual instrumentation for gutta percha removal during retreatment. METHODS Forty-eight single rooted premolars were prepared and obturated using gutta percha and AH Plus sealer using lateral compaction technique. Samples were randomly divided into four groups of 12 specimens each. Group 1 was retreated with Hedstrom Files (H-Files), group 2 was retreated with pro taper universal retreatment files (PTUR), group 3 with R-Endo retreatment files and group 4 with Neoendo retreatment files. Time taken for the retreatment was recorded for each tooth using a stopwatch. The samples were sectioned longitudinally and observed under a stereomicroscope. Digital images were taken and analysed using digital image analysing software. The data was statistically analysed using Kruskal-Wallis and Post-hoc Mann-Whitney test. RESULTS The Neoendo group showed significantly lower amount of residual material compared to PTUR, R-Endo and the H-Files (P = 0.00). The maximum residual material was observed in the H file group. The time taken for gutta percha removal was least for the Neoendo group followed by PTUR, R-Endo and H-Files. CONCLUSIONS None of the instruments were able to remove the filling material completely. Gutta percha removal using Neoendo and protaper universal retreatment files were faster and more efficient compared to REndo and H files. KEY WORDS Endodontic Retreatment, Protaper Universal Retreatment Files, R-Endo, Neoendo, HFiles

The aim of the study was to determine the effective pH of calcium hydroxide Ca(OH) 2 against Enterococcus faecalis, the most frequently isolated bacterial species in endodontic failure. Solutions of Ca(OH) 2 with different pH values of 9, 11 and 12.5 were prepared by dissolving 1 mg of Ca(OH) 2 in distilled water. The test solutions were grouped as follows: Group I, vials containing phosphate buffered saline pH of 7.2 as control; Group II, aqueous calcium hydroxide with pH of 9; Group III, aqueous calcium hydroxide with pH of 11; Group IV, aqueous calcium hydroxide of pH 12.5.Forty sterile paper points were transferred to Trypticase Soy Agar broth containing Enterococcus faecalis for a period of 10 min, then transferred to vials containing 1 mL of the test solutions and incubated for 1 h at 37 o C. The paper points were then transferred to neutralizing broth with glass beads to resuspend the microorganisms. Ten-fold serial dilutions were performed using aliquots of 250 µL from the broth and the same amount was plated onto blood agar plates. The plates were incubated anaerobically at 37 o C for 24 h. The number of colony forming units for each dilution was counted using the colony counter. The inhibitory effects of different pH groups on the bacteria were as follows: Group IV > Group III > Group II > Group I in an ascending order. This study revealed that Ca(OH) 2 at a pH 12.5 was effective in complete elimination of Enterococcus faecalis.

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