CORRELATION BETWEEN ALTERED ENAMEL MINERAL CONTENT AND FINAL TOOTH SHADE

Abstract

Objectives: This study was conducted to evaluate the correlation between alteration of enamel mineral content and tooth shade. Materials and Methods: A total of 33 sound bovine enamel blocks (5 x 5 mm, 2 mm thickness), were obtained from the middle third of the labial enamel surface. The samples were divided into three subgroups (n=11/group), where Group I received no surface treatment; Group II represents the demineralized enamel surface, Group III represents the remineralized enamel surface. Scanning Electron microscopic (SEM) examination and Elemental Analysis (EDXA) testing, as well as Color measurement using a color spectrophotometer and micro-hardness evaluation were performed for all samples. Results: The L values revealed a significantly strong negative correlation with carbon (r = -0.74, p = 0.002), but being positively correlated for oxygen (r = 0.59*, p = 0.02215), phosphate (r =0.62*, p = 0.01315) and calcium (r = 0.76, p = 0.00115). In contrast, both a and b values were only positively correlated for carbon (r = 0.67**, p = 0.006; r = 0.72**, p = 0.003 respectively), and negatively correlated for the rest of elements. Vickers microhardness values on the other hand were only negatively correlated with carbon (r = -0.88**, p = 0.000), but positively correlated for the rest elements. Conclusions: The change in the surface elemental content of the bovine enamel affected the lightness and the blue-yellow axis of tooth color, correlating respectively with the L* and b* values.