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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 2  »  Interleukin-1 and tumour necrosis factor- levels in periapical exudates
Interleukin-1 and tumour necrosis factor- levels in periapical exudates
Introduction - Materials and methods.



T. Ataoglu, M. Üngör, B. Serpek, S. Haliloglu, H. Ataoglu  & H. Ari
Departments of Periodontology,  Endodontics, and Maxillofacial Surgery, Dentistry Faculty
Department of Biochemistry, Veterinary Faculty, Selcuk University, Konya, Turkey

Introduction.
It is well known that bacterial infection of the dental pulp results in the formation of periapical lesions and causes the destruction of bone in the periapical region. The presence of immunocompotent cells such as macrophages, T and B cells and plasma cells has been demonstrated in human periapical lesions, suggesting that the host immune response is involved in the pathogenesis of the disease (Stern et al . 1981, Matthews & Mason 1983, Torabinejad & Kettering 1985, Torabinejad et al . 1985).
Cytokines such as interleukin-1 (IL1- ), interleukin- 1 tumour necrosis factor- (TNF- ) are soluble mediators and released from immunocompotent cells in inflammatory processes. These cytokines stimulate bone resorption, prostaglandin synthesis and protease production by many cell types, including fibroblasts and osteoblasts (Dewhirst et al . 1985, Beutler & Cerami 1986, Billingham 1987, Lorenzo et al . 1987, Tatakis et al . 1988). The local production of PGE 2 , IL1- and TNF- has been shown in periapical lesions (Artese et al . 1991, McNicholas et al . 1991, Shimauchi et al . 1998).
Exudate is a product of the inflammatory response that contains host mediators associated with the response. In previous reports, periapical exudate collected from root canals have been used to study host responses in endodontic lesions and detectable levels of IL1- , IL1- , PGE 2 and TNF- in periapical exudates were demonstrated (Safavi & Rossomando 1991, Matsuo et al . 1994, Takayama et al . 1996). Reports attempting to correlate the levels of cytokines and clinical signs in involved teeth are rare and the results are conflicting. In this regard, the present study aimed to determine IL1- and TNF- levels in periapical exudates and to evaluate the possible relationships between these cytokines and clinical signs in the involved teeth.

Materials and methods.

Subjects.
Patients scheduled to undergo root canal treatment because of periapical lesions were selected for the study. The aim of the study was explained to patients and consent was obtained. The medical histories of all patients were non-contributory. Samples of periapical exudates were obtained from root canals of 35 single-rooted teeth with radiolucent areas around the periapex. None of the lesions were related to marginal periodontitis and none extended to the maxillary sinuses.

Clinical findings.
Clinical signs associated with the involved teeth, including swelling, fistula on the periapical mucosa, tenderness to percussion, pain on palpation of the periapical mucosa and pus discharging in the canal, were evaluated and recorded at the sampling visit. Pus discharge was judged by the colour, transparency and viscosity of the exudate. For comparisons of cytokine levels in periapical exudates, teeth were divided into two groups according to presence or absence of clinical signs, including pain on percussion and/or on palpation of overlying mucosa, swelling and/or fistula, and pus discharge from the canals. A radiographic examination was completed at the time of sampling. The paralleling technique or the bisectingangle technique were used. Sizes of radiolucent areas around the periapex were determined by two examiners. Periapical lesions were classified as small when the long axis of the radiolucent area was shorter than 1 cm and all the others as large. Periapical exudate cytokine levels of teeth with large and small lesions were also compared.

Sampling of periapical exudates.
The involved teeth were isolated with a rubber dam. Penetration to the pulp chamber and unroofing were made by low-speed round burs as preparations for entering the chamber. The tooth was accessed carefully, without contamination by water or irrigants. Following the measurement of the working length, the root canal was enlarged to size 40. After the root canal was dried with sterilized paper points, two size 40 paper points (Absorbent paper points, Kerr Manufacturing Co., Romulus, MI, USA) were subsequently inserted into the root canal close to the established working length and held for 30 s. In actively draining teeth, paper points were taken out immediately or left for a few s in the canals. If the paper point withdrawn from the canal was dry, a thin endodontic file was used carefully to penetrate through the apical foramen to bring exudate into the root canal from the periapical area. Blood was occasionally seen in the suppurative exudates. The tooth was excluded from the study when more than a small amount of visible blood was present. The wetted length of paper points was measured immediately. The volume of the fluid was calculated from a standard curve as described before (Shimauchi et al . 1996) and expressed as L. Both paper points were placed in a tube containing 250 L of PBS, vortexed for 1 min and stored at –30 C until time of assay. Routine treatment of the patient was then continued.

Measurement of IL-1 and TNF- levels.
IL-1 and TNF- were measured by enzyme-linked immunosorbent assays. Assays were carried out in accordance with manufacturer’s instructions (Immunotech, Marseille, France). The amount of IL-1 and TNF- were determined by reference to standard curves (0–1000 pg mL –1 ) constructed with each assay. The concentrations of IL-1 and TNF- in each sample were calculated based on the dilutions and exudate volumes. The results were expressed as nanograms per mililiter (ng mL 1 ) for cytokine concentration.

Data analysis.
IL-1 and TNF- levels in the periapical exudates were compared between groups by using Mann–Whitney U -test. The relationships between cytokine levels and exudate volumes were determined by using Pearson correlation coefficients.