Effects of Intraligamentary Injection of Osteogenic-Induced Gingival Fibroblasts on Cementum Thickness in the Dog Model of Tooth Root Resorption.

Tooth root resorption is an unwanted result of orthodontic tooth movement, and it can be expressed by a reduction in cementum thickness. The aim of this experimental study was to evaluate the effect of intraligamentary injection of osteogenic-induced gingival fibroblasts (OIGF) on cellular and acellular tooth root cementum thickness in modeled orthodontic tooth movement. Six beagle dogs were used in the study. All the upper and lower third and fourth premolars were subjected to mechanical loading for 4 weeks, which induced orthodontic tooth movement. Fifteen premolars were assigned to the OIGF group, which received a single OIGF injection through the periodontal ligament near the root apex (n = 7 teeth), and to the control group, which received a single injection of Dulbecco's modified eagle's medium in the periapical area (n = 8 teeth). The evaluation of histomorphometry was performed to assess the thicknesses of cellular and acellular cementum at the root apex and four bilateral sites distal to the apex. We found no statistically significant enhancing effects of gingival fibroblasts on either cellular or acellular cementum thicknesses when compared with the control group. We conclude that a single intraligamentary injection of OIGF does not stimulate the formation of tooth root cementum in the dog model of orthodontic tooth movement. Thus, OIGF is unlikely to prevent orthodontic-induced tooth root resorption.