Comparison of Healing of Apical Periodontitis in Periodontally Diseased and Healthy Patients.

Endodontic treatment comprises bio-mechanical preparation of root canal system, chemical debridement and obturation with inert material. Various prognostic factors like adequacy of root filling, pre-operative size of periapical lesion on radiograph, type and location of teeth, periodontal status of the teeth and coronal restoration may play role in the success of endodontic treatment.

In the presence of defective coronal seal percolation of saliva and microbes may take place causing treatment failure. This assumption has acquired support mainly from various in-vitro studies which has demonstrated penetration of dye /microbe / radioactive tracer along root filling. Marshall and Massler in an in-vitro study using radioisotopes were first to highlight effect of coronal leakage and later Swanson and Madison in a study involving 70 extracted single rooted human teeth showed complete dye penetration throughout obturation material and along the canal walls. Since then there has been a renewed interest in the endodontic community in exploring relation of coronal seal with prognosis of endodontic treatment.

In a retrospective study Ray and Trope concluded that coronal restoration has greater impact on success of endodontic therapy rather than quality of root filling. However, various other epidemiological studies failed to replicate this result. A recent meta-analysis stated that problem of coronal leakage may not be of that clinical significance as demonstrated in various in-vitro studies, though importance of good coronal restoration and good root filling in the success of endodontic treatment can't be denied.

Placing an additional protective barrier in the coronal portion of the root canal has been recommended to minimize microleakage and facilitate healing of apical periodontitis. Intraorifice barrier apart from enhancing probability of success of endodontic treatment may also augment periodontal therapy as intra pulpal infection may also contribute in worsening of periodontal health by promoting marginal bone loss and pocket formation. Similarity between microflora of periodontium and root canal has led to a view that the communication between the two exists, and can potentially affect status of one another. The observations on this issue have been conflicting in nature with some authors reporting pulpal necrosis due to periodontal disease, and others reporting normal teeth regardless of severity of periodontal disease (Zehnder). Stassen et al. in a retrospective study observed more signs of apical periodontitis in teeth with reduced marginal support. They also reported significant influence of coronal extent of obturation on outcome of endodontic treatment in periodontally compromised patients. Significantly less incidence of apical periodontitis was seen where gutta percha was apical to marginal bone as compared to gutta percha being coronal to marginal bone. It is evident that the interrelationship between root canal and periodontium is complicated, and still not fully understood on account of lack of studies exploring the topic So far no prospective clinical trial has investigated the effect of periodontal status on healing of apical periodontitis. Also in absence of a clinical study substantial amount of doubt still persists whether intraorifice barrier can emerge as an effective mean to prevent microleakage in furcation and root canals of a multirooted tooth which because of its anatomical aberrations poses stiff challenge for clinicians. Therefore aim of this study was to determine effect of the periodontal status on periapical healing and to determine effect of intracanal glass ionomer restoration as intraorifice barrier on treatment outcome of apical periodontitis.

Clinical procedure:

After initial periodontal therapy, Standard root canal treatment was done using standard protocol. The canals were prepared with Revo S instrument according to manufacturer instructions and obturation was done using gutta percha. First of all, local anesthesia was administered using 2% lignocaine hydrochloride with epinephrine 1:80,000 (ICPA Health Products Ltd, Ankleshwar, India) and tooth was isolated under rubber dam. Caries excavation was done and access cavity was prepared using carbide burs in high speed hand-piece with copious irrigation. The pulp chamber was debrided and all canal orifices were identified and coronally enlarged with low speed Gates Glidden drills (Mani Inc, Utsunomiya, Tochigi, Japan). Working length was determined using Root ZX apex locator (J. Morita, Irvine, CA) and verified radiographically. After creating glide path with #15 k-file, Revo-S (Micro Mega, Besancon, France) instruments were used in sequence as suggested by manufacturer with a rotational speed of 350 rpm at torque setting of 2.5 Ncm in gentle in-out motion. Irrigation was carried out using 5 mL of a 5.25% Sodium hypochlorite (NaOCl; PrevestDenpro Ltd, Jammu, India) solution between files with 26 gauge side vented needle (Neelkanth Healthcare Pvt. Ltd, Jodhpur, Rajasthan, India). After preparation, the root canals were irrigated with 5 mL 17% EDTA (Canallarge, Ammdent, Mohali, India) for 1 minute to remove smear layer, followed by final irrigation with 5 mL 5.25% NaOCl. The root canal was then dried using paper points and filled with laterally condensed gutta-percha (Meta Biomed Co Ltd, Korea) and zinc oxide eugenol sealer (Dental Products of India Ltd, New Delhi, India). Gutta-percha was cut with a heated instrument and vertically condensed right at the orifice opening of the canals.

The teeth were then randomly sub-divided into 3 experimental groups IOB, Base and Control. In IOB group gutta-percha was removed 3 mm from the coronal portion of the canal with heated plugger, while it was left at the level of orifice in base and control groups. Thereafter, coronal restoration of composite resin was done in all groups. In IOB group orifice was sealed with GIC and base of GIC was applied in both IOB and base group before composite restoration