Interfacial evaluation of experimentally weakened roots restored with adhesive materials and fibre posts: an SEM analysis.
OBJECTIVE
To evaluate the bonding interface in experimentally weakened roots reinforced with adhesive restorative materials and quartz fibre posts, varying the light-exposure time of the composite resin used for root reinforcement.


METHODS
Twelve extracted human maxillary incisors teeth were used. The crowns were removed and the roots were endodontically treated. After post space preparation, the roots were assigned to four groups. The thickness of the root dentine was reduced and adhesively restored with composite resin light-activated through a translucent fibre post for either 40s (group 1), 80s (group 2) or 120s (group 3). In the case of control (group 4), the roots were not weakened. One day after post cementation, the specimens were sectioned transversally in three slices and processed for scanning electron microscopic analysis to observe bonding interface formation, quality of the hybrid layer and density of resin tags using a four-step scale method.


RESULTS
Formation of a hybrid layer and resin tags were evident in all groups. There was no statistically (p>0.05) significant difference between the regions analysed in each group (Friedman test) and between groups in each section depth (Kruskal-Wallis test). Furthermore, comparison of the flared/reinforced groups showed that the different times used for composite resin cure did not affect the results significantly (Kruskal-Wallis test, p=0.2139).


CONCLUSIONS
Different light-exposure times used for composite resin polymerisation during root canal reinforcement did not affect significantly the formation and quality of the dentine/adhesive/composite resin bonding interface.
School of Dentistry, University of Ribeirão Preto (UNAERP), Ribeirão Preto, SP, Brazil.
Cleonice
C
da Silveira Teixeira
Mara Cristina
MC
Santos Felippe
Yara Teresinha Correa
YT
Silva-Sousa
Manoel Damião
MD
de Sousa-Neto
D003799:Dental Stress Analysis; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000528:radiation effects; D006801:Humans; D007180:Incisor; D055115:Light-Curing of Dental Adhesives; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique; D019279:Resin Cements / Q000528:radiation effects; D013997:Time Factors
D017220:Dentin-Bonding Agents; D019279:Resin Cements