Introduction
The Infectious Process
The periodontal ligament and root canal system have a common developmental, anatomic, and functional relationship.1-3 They are connected by anatomic structures such as apical foramina, accessory canals, and dentinal tubules4-7 as well as by pathologic pathways such as tooth perforations and fractures.8-12 Theoretically an infection originating in one tissue will affect these other related tissues.
Lateral and accessory canals are common in maxillary third molars, maxillary central incisors, and in the lateral incisors.7 Accessory canals were observed using a microscope in the furcation area in 74% of the molars,13 with most located in the apical third of that area. However, accessory canals can be found anywhere along the root canal.14 Treatment and prognosis are influenced by the presence of accessory canals when inflammation occurs in the bifurcation area.
Accessory canals in the bifurcation area were found in 21% of monkeys and dogs with necrotic pulps.15 An inflammatory response due to viable pathogens and their by-products was found in the periodontal ligament, the apical foramen, and the area of the accessory canal openings of these teeth.
The main etiologies of pulp pathology are bacteria, viruses, and fungi16-21 capable of influencing periodontal structures. However, the influence of pulp pathology on periodontal disease has not been fully explained. The spread of infection from the root canal to the periodontal ligament is due to combined anatomic routes. A relationship has been found between periapical lesions and the periodontal ligament.22-24
Treatment Modalities
Treatment modalities of combined periodontal-endodontic lesions should eliminate pathogens from the infected area and prevent their re-colonization. After root canal treatment and obturation, the main route for bacterial colonization is coronal leakage.27 Bacteria in dentin tubules, root canal ramifications, isthmuses, and the apical delta can present persistent infections.28,29 Dentin tubules sealed with dentin adhesives is an accepted treatment modality in restorative and esthetic dentistry. Dentin adhesive re-treatment with Gluma Desensitizer (Heracus Kulzer, Hanau, Germany) inhibits bacterial growth under composite restorations.30 Successful clinical and histologic results of retrograde obturation can be achieved with dentin-bonded modified resin composite.31 Since dentin adhesives penetrate up to 5 mm into the dentinal tubules coronal and apical leakage is prevented.32 The application of dentin adhesive technology has not been described as a part of endodontic treatment.33
An important etiologic factor in pulp pathology is periodontal disease and its treatment.25,26 The objective of the present study was to suggest a novel treatment modality for periodontal bifurcation lesions of endodontic origin.
