ABSTRACT
Aim: The aim was to study the ultrastructure of dentin exposed by attrition, abrasion and erosion separately and in combination and to visualize the lesions using scanning electron microscope and thereby establish a superior basis for evaluating dentinal changes at the ultra-structural level and to correlate the findings with changes seen at the light microscopic level. Study Design: Tooth wear is often multifactorial. Loss and excessive wear of hard dental tissues is a permanent problem of the dentition, especially in present era, encompassing almost all age groups. In this study 40 extracted teeth were used. Four groups were made and comparison was made between light microscope and scanning electron microscopic findings. Place and Duration of Study: Department of oral and maxillofacial pathology, career post graduate institute of dental sciences, lucknow, (U.P.), India. Methodology: Forty extracted permanent teeth (10 attrited, 10 abraded, 10 eroded and 10 normal premolars and molars) were sampled divided into four groups. After debridement and fixation in 10% formalin for 24-48 hours, the teeth were fractured along their longitudinal axes. Two halves of the teeth were studied under scanning electron and light microscope. The dentinal changes secondary to attrition, abrasion and erosion such as dead tracts, dentinal sclerosis and reparative dentin formation seen under light microscopy, were correlated with the ultra-structural findings. The data so obtained were tabulated and statistically analyzed. Results: The light microscopic finding of 4 randomly selected teeth, showed frequency of tertiary dentin significantly more than dead tracts and dentinal sclerosis was absent, from each group. 10 samples scanned with electron microscope showed the tubular surface/margins smooth, tubular surface/margins rough and presence of crystals was highly significant (p<0.001) whereas peritubular dentin and intertubular dentin, was not significant (p>0.05) in each group. Similarly, mean density of dentinal tubules of normal group was the highest followed by abraded, attrited and eroded the least. The percentage of affected dentinal tubules was most in eroded & least in attrited teeth. Conclusion: The scanning electron microscope is a powerful magnification tool which offers extremely high resolution. In the present study, scanning electron microscopic image complements the information available from the light microscope about the dentinal changes in abraded, attrited and eroded teeth.