Healing of Intrabony Defects and Its Relationship to Root Canal Therapy. A Histologic and Histometric Study in Dogs

Abstract

The purpose of this study was to evaluate the importance of root canal therapy in the healing process of severe intrabony defects. Four beagle dogs were used and 32 interproximal intrabony defects, up to the apical third, were created. Wire ligatures were placed into these defects for plaque accumulation. Three weeks later, the ligatures were removed and 4 different treatment modalities were employed: group 1) scaling and root planing (SRP); group 2) modified Widman flap (MWF); group 3) modified Widman flap and root canal therapy performed at the same time (RCT/MWF); and group 4) modified Widman flap and root canal therapy performed 3 weeks after the surgical procedure (MWF + RCT). Postoperative oral hygiene was obtained by spraying a 0.12% chlorhexidine solution 3 times a week. The animals were sacrificed 7 weeks after treatment. Blocks were obtained and processed for routine histology. Results were expressed as a percentage of the total defect length (TDL). No differences were observed when SRP was compared to MWF. New bone formation (BF) presented better results for SRP (43.4%) and MWF (53.4%) when compared to RCT/MWF (15.5%). New cementum formation (CF) presented better results for SRP (59.8%) and MWF (64.6%) when compared to RCT/MWF (19.3%) and MWF + RCT (31.5%). Connective tissue repair (CTR) presented better results for SRP (72.4%) and MWF (74.2%) when compared to RCT/MWF (47.5%) and MWF + RCT (44.4%). Results were statistically significant at the level of 0.05. Within the limits of this study, it was concluded that root canal therapy performed simultaneously or 3 weeks after surgery modified the healing of intrabony defects, impairing new bone formation, new cementum formation and new attachment.

Influence of Endodontic Treatment in the Post‐Surgical Healing of Human Class II Furcation Defects

“…The apparent discrepancy of the findings reported here and previous reports of the literature may be explained by the significant differences in the methodologies used, including the experimental system (in vitro 1,8 versus animal 3,9,10 versus human 4,5,7,11 ), the evaluation method (histology 3‐5,9,10 versus clinical 7,11 ), or treatment procedure (replantation, 2 non‐surgical instrumentation, 3 or surgical instrumentation 3,9,10 ). In considering only the human studies available, significant differences are also noted.…”

“…In considering only the human studies available, significant differences are also noted. Some studies failed to document the type of the ET provided 3 or used currently obsolete endodontic materials and techniques 4,5 . Previous reports frequently failed to report the adequacy of the ET or its efficacy in eradicating the endodontic infection and/or periapical radioleucency 4,5,7 .…”

“…The impact of the endodontic treatment (ET) of the tooth on the healing potential of the periodontium has been a matter of controversial debate in the literature 1‐11 . Culturing studies in vitro demonstrated that selected root canal fillers and materials (gutta‐percha with Roth zinc oxide and eugenol‐based sealer, warm gutta‐percha with sealer, warm gutta‐percha without sealer, calcium hydroxide, or formocresol) may reduce fibroblast adhesion to endodontically treated root surfaces 1 .…”

“…Culturing studies in vitro demonstrated that selected root canal fillers and materials (gutta‐percha with Roth zinc oxide and eugenol‐based sealer, warm gutta‐percha with sealer, warm gutta‐percha without sealer, calcium hydroxide, or formocresol) may reduce fibroblast adhesion to endodontically treated root surfaces 1 . Animal studies in vivo suggested that optimal periodontal healing may be influenced by the presence, quality, and timing of ET 2,3 . ET performed simultaneously with or a short time before surgical and non‐surgical periodontal treatment resulted in inhibited histologic healing 3 .…”

“…Animal studies in vivo suggested that optimal periodontal healing may be influenced by the presence, quality, and timing of ET 2,3 . ET performed simultaneously with or a short time before surgical and non‐surgical periodontal treatment resulted in inhibited histologic healing 3 . Evidence in human studies has also been reported, linking previous ET with reduced healing potential of the periodontal structures 4‐7 .…”