Oral cavity evaluation and dental chart registration of coati (Nasua nasua) in captivity.

The aims of this study were to develop a dental evaluate any oral cavity disease, develop gypsum models of the dental arches, and to register the occlusions found in coatis (Nasua nasua) in captivity Formulation of the dental chart was assisted by intraoral radiographs from the head of an adult coati cadaver of the same species with the following dental formula.: I 3/3, C 1/1, P 4/3, M 2/2. Seven live coatis of the Nasua nasua species were evaluated. Five of the seven coatis presented with various dental abnormalities as follows: dental plaque (71.4 0%), gingivitis (71.4 %), periodontitis (57.1 %), dental stain (42.9 %), dental abrasion (57.1 %), dental fracture (57.1 %), pulp exposure (42.9 %), malocclusion (57.1 %) and supernumerary teeth (14.2 %).

A retrospective clinical, radiographic and microbiological study of periodontal conditions of teeth with and without crowns.

The aim of this study was to evaluate retrospectively the periodontal conditions of teeth with fixed crowns that had been in place from 3 to 5 years before the study was conducted. Forty individuals were recalled for a follow-up visit. Full-mouth clinical examinations were carried out and Visible Plaque Index (VPI), Gingival Bleeding Index (GBI), Probing Pocket Depth (PPD), and clinical attachment level (CAL) were assessed in 6 sites per tooth. Parallel radiographs were also taken and blindly analyzed by a digital caliper (distance between the apex and the bone crest). BANA tests were performed. A contra-lateral sound tooth was considered the control. Mean values were obtained and Wilcoxon and paired sample t tests were used to compare the test and control sites. Crowns had a mean VPI value of 30.42% as compared to 49.17% for sound teeth. The GBI was 33.33% and 26.25% for test and control teeth respectively. Assessment of PPD revealed values of 2.30 and 2.14 mm, and assessment of CAL revealed averages of 2.02 and 1.89 mm for test and control teeth respectively. The mean values for radiographic distances were 12.73 and 13.67 mm, and for the BANA test, 67.50 and 50.00 for sound and crowned teeth, respectively. Statistically significant differences were observed for all parameters except for CAL and for the BANA test. It may be concluded that, with the methods used in the present study, crowns may be associated with more signs of inflammation, however not with periodontal breakdown.

Effects of Nd:YAG laser on enamel microhardness and dental plaque composition: an in situ study.

OBJECTIVE: This study evaluated Knoop microhardness (KHN) and dental plaque composition of human enamel irradiated with Nd:YAG laser and subjected to in situ cariogenic challenge. BACKGROUND DATA: Although in vitro studies have shown that Nd:YAG laser irradiation results in a reduction of enamel mineral loss after acid challenge, this hypothesis has not been tested using an in situ caries model. METHODS: Acrylic devices containing lased and non-lased human enamel slabs were used for 28 days by eight subjects highly colonized by S. mutans. Devices were immersed in a sucrose solution (20%) eight times daily in order to better simulate the cariogenic challenge. RESULTS: After the experimental period, no differences in dental plaque composition were observed between lased and non-lased enamel slabs indicating that all slabs were exposed to equivalent cariogenic challenges. Cross sections of enamel slabs were then measured for Knoop microhardness at 10, 20, 40, 60, 80, 120, and 180 microm in depth from the outer exposed surface. Un-lased enamel slabs not subjected to the in situ cariogenic challenge were also used as control. Enamel slabs from the two in situ groups exhibited lower hardness when compared to control. Lased enamel showed higher hardness values up to 60 microm in depth than the un-lased enamel exposed to in situ cariogenic challenge. CONCLUSION: The results suggest that the irradiation of Nd:YAG laser of human enamel appears to be effective for increasing enamel hardness and thus decreasing the effect of acid attack.

An electron microscopic study of dental plaque of the rat incisor.

Because rat incisors continuously erupt they provide an opportunity for the study of dental plaque at all stages of its development. The youngest plaque would be visible at the gingival margin of the tooth as it erupts, and the older plaque higher on the tooth. The ultrastructural features of these plaques were studied by transmission electron microscopy. Cocci and short rods colonized the cementum surface, forming a monolayer. The plaque had a maximum thickness of about 40 microns, with the inner third rich in fibrillar matrix and the organisms forming microcolonies perpendicular to the tooth surface. Cells were haphazardly distributed in a loose matrix on the surface of the plaque. In the area of plaque disorganization the cementum was covered by isolated groups of bacteria and the matrix had holes in it. The rat mandibular incisor may provide a unique model for study of how plaque on cementum is initially formed, matures and finally is degraded.