Morphological Study and Analysis of Microhardness and Permeability of the Furcation of Maxillary Premolars

Abstract

The morphology, microhardness and dentin permeability of the furcation region of maxillary premolars were evaluated. Ten premolars were cut lengthwise and the furcation region was delimited. In one group (n=10) microhardness was measured in the buccal, central and palatal regions, in the outer middle and inner layers of the furcation, and in the buccal and palatal regions adjacent to the furcation. Knoop hardness was tested with 10 g load for 15 s. Data were analyzed statistically by ANOVA and Tukey-Kramer test (a=0.05). In the other group (n=10) confocal microscopy was used to study dentin morphology. Other 10 specimens were instrumented with ProTaper and immersed in 10% copper sulfate for analysis of permeability under light microscopy. About microhardness, there was no significant difference (p>0.05) among the buccal (39.9±3.1), central (39.5±4.4) and palatal (39.7±5.0) regions of the furcation, or between these regions and the adjacent buccal (39.1±5.8) and palatal (39.7±5.8) regions (p>0.05). The inner layer (42.3±3.7) had significantly higher microhardness (p<0.05) than the outer layer (37.1±3.9). There was a tendency of calcification of the dentinal tubules from the outer towards the inner layer. The percentage of stained area was 12.45±2.0%, restricted to the outer layer. The buccal, central and palatal regions of the furcation as well as the buccal and palatal adjacent regions had similar microhardness values. In conclusion, the inner dentin layer is harder than the outer dentin layer. The dentinal tubules are sinuous and intertwine towards the middle layer. Dye penetration is restricted to the outer layer.

Determinação do Módulo de Elasticidade da Dentina Radicular através ensaio de Dureza de Vickers

“…Tabela 2 -Valores do módulo de elasticidade (média, desvio padrão) dos terços cervical, médio e apical, na amostra 1. É possível visualizar, na figura 10 e na tabela 2, o terço cervical da amostra 1 com maior densidade tubular e menor valor de módulo de elasticidade (7,39GPa), comparado aos outros terços médio (9,75GPa) e apical (12,11GPa), podendo ser justificado, segundo o trabalho de Pashley et al (1985), Fuentes et al (2003) e Nascimento et al (2016), que afirmaram que a maior quantidade de túbulos está relacionada à menor dureza da dentina.…”