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The Structure of Cemento-dentinal Junction in Mandibular Deciduous Second Molars and Permanent First Molars in Egyptian Populations (Scanning Electron Microscope Study)

Introduction: Cementodentinal junction (CDJ) is the interface between cementum and dentin. The cause of this attachment was described by the intermingling of cemental and dentinal fibers or the accumulation of adhesive proteoglycans at the cementodentinal junction. Cementum was classified to three major types according to the type of fibers; Acellular extrinsic fiber cementum, Cellular intrinsic fiber cementum and Cellular mixed stratified cementum. Aim of Work: To observe the cemento-dentinal junction in human mandibular deciduous 2nd molar and mandibular permanent 1st molar by scanning electron microscopy combined by NaOH maceration. Materials and Methods: Twenty extracted mandibular deciduous 2nd molar and mandibular permanent 1st molar with complete root(s), were collected. The teeth preserved in 10% formalin then divided into two groups consisted of 10 teeth each. All teeth were cut mesiodistally into halves with a diamond desk, then the sectioned halves were demineralized by formic acid 10% for one month then were immersed in 10% NaOH aqueous solution for 2-3 days at room temperature and rinsed in distilled water overnight (24 hours). Results: Acellular cementum in mandibular deciduous 2nd molars showed a gap with complete separation, while in cellular cementum there is fibril poor gap and fibril intermingling between the intrinsic fibers of cellular cementum and dentin root fibers. The gap and the intermingling fibers were not observed in the examination of cellular cementum in mandibular permanent 1st molars while in acellular cementum there is a fiber intermingling observed. Conclusion: Fibril intermingling plays a role in cementum to dentin attachment. Received: 09 August 2020, Accepted: 01 September 2020