Periapical histopathological evaluation of two single-cone filling techniques in cynomolgus monkeys

Jianmin Han, DDS, PhD,a Hong Lin, DDS, PhD,a Gang Zheng, BE, PhD,a Lin Yue, DDS, PhD,b Yan Gao, DDS, PhD,c Xiuping Mao, DDS, PhD,b and Guang Hong, DDS, PhDd

aDental Materials Laboratory, National Engineering Laboratory for Digital and Material Technology of Stomatology, bDepartment of Operative Dentistry and Endodontics, cDepartment of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, P. R. China, and dLiaison Center for Innovative Dentistry, Graduate School of Dentistry, Tohoku University, Sendai, Japan

Purpose: To investigate the in vivo efficacy of two types of single-cone fillings in the vital pulp of cynomolgus monkeys.
Materials and Methods: Root canals were performed on a total of 34 teeth (42 roots) in four young adult cynomolgus monkeys with healthy permanent dentition. Two types of single-cone fillings (Gutta-Percha point and RealSeal point) were used. After 28 or 180 days of filling, filled teeth and supporting tissues were dissected free of the jaws of euthanized animals. Following demineralization and sectioning, the stained sections were scored microscopically for a series of histomorphological parameters. The scores between groups were analyzed by Kruskal-Wallis and Mann-Whitney U nonparametric tests. Tissue sections that were not cut through the apical foramen were excluded from evaluation.
Results: There were 32 roots that were suitable for evaluation. Most samples did not show significant inflammatory responses, although a few of the 28-day specimens did exhibit mild mononuclear cell infiltration and accumulation close to the filling material. For all histomorphological parameters, there were no significant differences between the four groups. Nearly one third of the evaluated roots showed the presence of the sealer outside of the apical foramen without gutta-percha overfilling. In two of these samples, overfilling materials were encapsulated by the epithelial cell rests of Malassez.
Conclusion: Both types of gutta-percha fillings (gutta-percha points and RealSeal points) and the sealer used in this study demonstrated favorable tissue compatibility. The single-cone filling technique may result in a higher risk of sealer extrusion.
(Asian Pac J Dent 2014; 14: 41-47.)
Key Words: biocompatibility, endodontic sealer, gutta-percha point, single-cone filling technique