Risk Factors Associated with Denture Stomatitis in Healthy Subjects Attending a Dental School in Southeast Iran

Objectives: There is scant information regarding the multifactorial aetiology of denture stomatitis (DS) in the world and, despite its frequency, associated factors are not completely understood. The aim of this study was to investigate the risk factors that may be associated with this lesion. Methods: A total of 70 edentulous patients, all wearing removable dentures, were divided into two groups. The test group comprised 43 patients with DS and the control group comprised 27 subjects with clinically healthy palatal mucosa. A thorough history-taking and physical examination were carried out; the subjects also answered a questionnaire. The serum level of vitamin A for each subject was assayed from a blood sample taken after the examination. Results: This study showed a significant relationship between the incidence of DS and three major factors: denture age (in terms of years), the practitioner manufacturing the dentures (general dental practitioner versus dental hygienist), and the nightlong wearing of dentures. Also, the vitamin A serum level was low in 94.29% of all subjects (cases and controls). Conclusion: Although many predisposing conditions were related to this situation, the most important risk factor was the continuous use of the dentures

Scanning Electron Microscopic Evaluation of Residual Smear Layer Following Preparation of Curved Root Canals Using Hand Instrumentation or Two Engine-Driven Systems

Introduction: In this experimental study, the amount of smear layer (SL) remnants in curved root canals after chemomechanical instrumentation with two engine-driven systems or hand instrumentation was evaluated. Methods and Materials: Forty-eight mesiobuccal roots of mandibular first molars with curvatures ranging between 25 and 35 degrees (according to Schneider’s method) were divided into three groups (n=16) which were prepared by either the ProTaper Universal file series, Reciproc single file system or hand instrumentation. The canals were intermittently irrigated with 5.25% NaOCl and 17% (ethylenediaminetetraacetic acid) EDTA, followed by distilled water as the final rinse. The roots were split longitudinally and the apical third of the specimens were evaluated under 2500× magnification with a scanning electron microscope (SEM). The mean scores of the SL were calculated and analyzed using the non-parametric Kruskal-Wallis and Mann-Whitney U tests. Results: The mean scores of the SL were 2.00±0.73, 1.94±0.68 and 1.44±0.63 µm for the ProTaper Universal, Reciproc and hand instrumentation, respectively. Mean score of SL was significantly less in the hand instrumentation group than the ProTaper (P=0.027) and Reciproc (P=0.035) groups. The difference between the two engine-driven systems, however, was not significant (P=0.803). Conclusion: The amount of smear layer in the apical third of curved root canals prepared with both engine-driven systems was similar and greater than the hand instrumentation technique. Complete cleanliness was not attained.Keywords: Canal Preparation; Endodontics; Irrigants; Scanning Electron Microscopy; Smear layer

Identification and categorization of hazards in the mining industry: A systematic review of the literature

Control of OHS risks in the mining industry has been attracting increasing attention in recent years. Because of their great diversity in a complex system, hazards can be difficult to identify and classify, especially when system components interact. Risk cannot be managed successfully without comprehensive investigation of all its aspects. A coherent and integrated classification for identifying and categorizing all hazards is currently lacking in mining. We propose an integrated system classification of OHS hazards in mining based on our review of 44 studies retrieved using PRISMA. Considering Canadian and international standards, regulations and conventions, new hazard categories are proposed and hazard prevention is discussed from 12 perspectives: physical, chemical, biological, ergonomic, accident and psychosocial risks, as well as policy, legislation, management, design, geography, and uncertainty, with reference to each of the four phases of a typical mine life cycle, the hazards were shown in a portrait. This paper provides suitable categories based on rational data for creating a portrait in order to OHS hazards prevention in life cycle activity in mine