Does Surface Enamel Composition and Characteristics Vary With Inter Proximal Enamel Reduction ?

Abstract Objective :This study aimed to evaluate the chemical composition of the proximal enamel surface and the surface characteristics subjected to different extents of Inter- proximal reduction(IPR) in a clinical setting Materials and methods:Premolars of orthodontic patients which were designated for extraction were subjected to .2mm,.3 mm and .5 mm of IPR. After one month the teeth were extracted and the teeth were subjected to Scanning Electron Microscope (SEM) and Energy Dispersive X ray Spectroscopy (EDX). Results: Calcium Phosphorous stoichiometric ratios for all the four groups assessed with EDX was compared using Mann Whitney U test (0.86, 0.76, 0.56, 0.64 respectively) and it was statistically insignificant (p=0.163). The SEM images of the three experimental groups (taken at magnification of 500X and 2000X showed that the enamel surfaces were irregular and rough compared to the honey comb appearance of the unstripped group. Small areas of erosion of enamel surface were seen in Group I (0.2mm) under 2000X magnification compared to Group IV (control) which showed typical arrangement of enamel rods in alternating orientation Conclusions:On analyzing the surface characteristics of enamel using SEM between the stripped and unstripped surfaces, there were irregularities and roughness seen in stripped surface whereas honey comb pattern was observed in unstripped enamel surfaces. The elements found in unstripped and stripped enamel surfaces were calcium, phosphorous, carbon, oxygen and nitrogen. Although the calcium and phosphorus were high in the 0.5mm IPR group, the difference between stripped and unstripped enamel surfaces were statistically not significant. Clinical relevance: IPR is a popular method of gaining space particularly in recent times.There have been concerns that IPR can remove the superfical mineral rich layer making the deeper layers more susceptible to carious attack. No study has studied the mineral content in different layers of enamel in response to IPR .The results of this study strengthens the validity of the clinical protocol employed.