The effects of intracanal medicaments, fillers, and sealers on the attachment of human gingival fibroblasts to an exposed dentin surface free of a smear layer

To date there has been very little research into the possible effects of endodontic therapy on regeneration of the lost periodontal attachment. The objective of this study was to examine the effects of endodontic medicaments on fibroblast attachment to dentin surfaces free of a smear layer. Pulp chambers of extracted third molars were filled with one of the following medicaments: gutta-percha with Roth's zinc oxide and eugenol-based sealer, warm gutta-percha with sealer, warm gutta-percha without sealer, calcium hydroxide, formocresol, cotton pellet, or left empty. A predetermined dentin surface area was then inoculated with human gingival fibroblasts at a concentration of 2 x 10⁴ cells per ml. The cells were allowed to adhere to the dentin surface for either 4 or 24 hours, then cell attachment was quantified using a methyl-tetrazolium assay. The data were analyzed using a Kruskal-Wallis one-way analysis of variance and Dunn's multiple comparison test. It was determined that fibroblast attachment was significantly reduced when exposed to formocresol or warm gutta-percha without sealer at both the 4 and 24 hour interval (P ≤ 0.05). This suggests that the use of formocresol or warm gutta-percha without sealer in a root canal may impede periodontal wound healing and regeneration.