Incipient Fissure Caries in Extracted Premolar Teeth from Young Orthodontic Patients

Abstract

This study was undertaken to find the relationship between the morphological characteristics of fissures and the prevalence and the extent of initial caries and to deduce the site of caries attack in the fissures of premolars extracted from orthodontic patients. The teeth were 124 premolars which appeared clinically sound, extracted from 61 children aged 8 to 15 years, and having electrical resistance values of above 600KΩ. Vertical bucco-lingual serial ground sections were prepared from each tooth and 835 sections were obtained.
The sections were observed by light and polarizing microscopy and by microradiography, and the size of fissures was measured using a profile projector.
The following results were obtained.
1. In the frequency of morphological characteristics, IK-type of fissures were 55, I-type 40, U-type 19, V-type 14, and other types 13 (Table 3).
2. In the prevalence of carious lesions, carious teeth were 54 out of 124 (43.5%), and carious fissures were 56 out of 141 (39.7%) (Table 5).
3. Regardless of morphological characteristics, all sites of carious lesions showed the same tendency: 56 (100%) were found at the outer third of the fissure, 55 (98.2%) at the fissure entrance, 47 (83.9%) at the middle third of the fissure, 34 (60.7%) at the inner third of the fissure, and 14 (25%) at the bottom of the fissure (Fig. 2, Table 6). From these findings, it was assumed that the main site of caries attack was probably at the outer third of the fissures.