Morphotypes of the apical constriction of maxillary molars: a micro-computed tomographic evaluation.

Objectives: The aim of this study was to evaluate and compare the apical constriction (AC) and apical canal morphology of maxillary first and second molars, using micro-computed tomography (micro-CT). Materials and Methods: The anatomical features of 313 root canals from 41 maxillary first molars and 57 maxillary second molars of patients with known age and sex were evaluated using micro-CT, with a resolution of 26.7 µm. The factors evaluated were the presence or absence of AC, the morphotypes, bucco-lingual dimension, mesio-distal dimension, and the profile (shape) of AC and the apical root canal. The apical root canal dimensions, location of the apical foramen (AF), AC to AF distance, and presence of accessory canals in the apical 5 mm were also assessed. Descriptive and analytical statistics were used for data evaluation. Results: AC was present in all 313 root canals. Patients' age and sex did not significantly impact either AC or the apical canal dimensions. The most common AC morphotype detected was the traditional (single) constriction (52%), followed by the parallel (29%) morphotype. The mean AC dimensions in maxillary first molars were not significantly different from those in maxillary second molars. Sixty percent of AF were located within 0.5 mm from the anatomic apex. Conclusions: The most common morphotype of AC detected was the traditional constriction. Neither patients' age nor sex had a significant impact on the dimensions of the AC or the apical root canal. The majority of AF (60%) were located within 0.5 mm from the anatomic apex.

Impact of dental operating microscope, selective dentin removal and cone beam computed tomography on detection of second mesiobuccal canal in maxillary molars: A clinical study.

INTRODUCTION: Maxillary molars may frequently require root canal therapy and can have complex anatomy. It is important to locate and treat the second mesiobuccal canal to significantly improve prognosis. AIM OF THE STUDY: The purpose of this study was to evaluate direct vision, dental operating microscope (DOM), selective dentin removal under DOM, and cone beam computed tomography (CBCT) in clinical detection of second mesiobuccal root canal (MB2) in maxillary molars. MATERIALS AND METHODS: A total of 122 maxillary first and second molars indicated for root canal treatment were included in our study. Following access cavity preparation, the presence of MB2 canal orifice was assessed in four stages. Stage I: with direct vision. Stage II: under DOM, Stage III: after selective dentin removal under DOM and Stage IV: teeth in which MB2 canal was not identified by Stage III were further investigated with CBCT. The number of canals identified during each stage was analyzed statistically. RESULTS: Clinical detection of MB2 canal in our study was 90%, with 93% in maxillary first molar and 86% in maxillary second molar. 64% MB2 canals were located at Stage I (direct vision) which improved to 84% at Stage II (under DOM) and 90% at Stage III (selective dentin removal under DOM). CBCT investigation (Stage IV) further improved the identification of MB2 canal leading to overall prevalence of 93%. CONCLUSION: The results of our study demonstrated that MB2 canal can be clinically detected in up to 90% of maxillary molars by the use of DOM and selective dentin removal. CBCT investigation is indicated when MB2 canals are not clinically detected.

Effect of two desensitizing agents on dentin hypersensitivity: A randomized split-mouth clinical trial.

BACKGROUND: Clinical research is important to evaluate the effect of desensitizing agents. AIMS: This randomized clinical trial evaluated the immediate and 1 week desensitizing effect of two desensitizing agents Uno Topical Gel and Profluorid. MATERIALS AND METHODS: Thirtyfive patients with teeth presenting with dentin hypersensitivity were included in this clinical trial. Each quadrant in a patient was randomly assigned to one of two groups: Uno Topical Gel or Profluorid Varnish. A VAS score was used to assess tooth sensitivity at baseline, immediately after application of desensitizer and after 1 week. Additionally, 30 dentin discs were prepared, divided into Group 1(Control Group), Group 2 (Profluorid Varnish) and Group 3 (Uno Topical Gel) and examined using scanning electron microscopy (SEM) after 1hour and 24 hours to evaluate tubule occlusion. STATISTICAL ANALYSIS: Clinical data were analysed using Friedman's test and Mann - Whitney U test. SEM data was analysed using Student's 2-sample t-test. RESULTS: Uno group was significantly better to evaporative stimuli immediately (P=0.01) after application. After 1 week, Uno group was significantly better to tactile (P=0.000) and evaporative (P=0.000) stimuli than Profluorid. SEM images showed that 1 hour after application, Uno and Profluorid demonstrated more than 90% and 80% dentin tubule occlusion respectively. At 24 hours, Uno and Profluorid demonstrated more than 50% and 60% dentin tubule occlusion respectively. CONCLUSIONS: Uno Topical Gel was significantly better than Profluorid in reducing pain of dentin hypersensitivity due to tactile and evaporative stimuli after 1 week.