Suppression of cementum-like tissue formation on BMP-2-applied dentin surface by bisphosphonate

Abstract

We studied the effects of bisphosphonate administration on cementum-like tissue formation and dentin resorption induced by BMP-2 in rats.
Incadronate (1μg/kg/day) was administered intraperitoneally to rats three times per week, from two weeks before implanting dentin blocks to the end of the observation period. Saline was administered under the same protocol without incadronate to the control group. We prepared 180 dentin blocks from rat teeth roots and treated them with 24%EDTA. Each block had 0,100 or 400μg/ml rhBMP-2 applied. Blocks were then implanted into palatal connective tissue of rats, and specimens were prepared 2, 4, and 8 weeks after implantation for histological and histomorphometric examination.
Results showed that dentin resorption in the control group was significantly greater than that in the experimental group (p<0.01). New cementum-like tissue formed in the experimental group was also significantly less than that in the control group (p<0.01). 80% of new cementum-like tissue were formed on resorption site of dentin and 20% on the nonresorption site. TRAP positive cell numbers did not show any significant difference between groups.
These findings suggested that osteoclast-like cells mediated new cementum-like tissue formation, and dentin resorption was suppressed by bisphosphonate administration and osteoclasts this play an important role in has been new cementum-like tissue formation on dentin surfaces to which BMP-2 applied. Nihon Shishubyo Gakkai Kaishi (J Jpn Soc Periodontol) 48 : 285-296, 2006.