Cementoenamel Junction in Egyptian Maxillary First Premolar: Scanning Electron Microscopy and Energy-Dispersive X-ray Analysis Study

Background:There is a controversy regarding shapes and distribution of the mineralized tissues that compose the cementoenamel junction (CEJ). Objective: The aim of this study was to investigate the morphology and frequency of various relationships of cementum, enamel and dentin at CEJ of Egyptian maxillary first premolars. Materials and Methods: The CEJ of a group of 50 caries and defect-free human maxillary first premolars extracted for orthodontic reasons was examined using stereomicroscopy, scanning electron microscopy (SEM) and transmitted light microscopy.The chemical profile of the tissues composing the CEJ was recorded using energy-dispersive X-ray analysis (EDXA) and was statistically analysed. Results: Light microscopic examination of ground sections revealed that edge-to-edge interrelation between root cementum and enamel was predominant (50 %). Cementum overlapping enamel was less prevalent than previously reported as it presented 36% of the samples. In approximately 10% of the samples, gap between cementum and enamel was observed. A fourth type of junction that was only reported by few authors, in which enamel overlapped cementum, had been detected in a small proportion (4%) of the samples. Statistical analysis of EDXA results showed that the highest Carbon wt % was in coronal cementum. Meanwhile, the highest Oxygen wt % was detected in the enamel overlapping cementum. However, the enamel showed the highest wt % of Phosphorus. Surprisingly, bare dentin demonstrated the highest wt % of Calcium.Conclusions:The present study demonstrated the highest frequency of edge to edge contact of cementum and enamel, contradicting the traditional frequencies which proves that the anatomical profile of CEJ might be race dependent.