Polyetheretherketone (PEEK) material is a polycyclic, aromatic, thermoplastic polymer that is semi-crystalline and has a linear structure. PEEK has good mechanical and electrical properties such as resistance to high temperature and resistance to hydrolysis. In addition, because of the property of high biocompatibility, use of PEEK has increased in orthopaedic and trauma cases. The most characteristic property of PEEK material is that it has a low elasticity modulus, close to that of bone. It has been suggested that stress-based problems could be reduced with this material due to the low elasticity modulus. In the light of this information, PEEK material could be considered as an alternative to conventional materials in the field of dentistry.

INTRODUCTION: Rotary instruments that are used for retreatment are very effective, but most of them leave root filling residue in the canal. The aim of this study was to evaluate the efficacy of removing gutta-percha-based root fillings with ProTaper retreatment files (Dentsply Maillefer, Ballaigues, Switzerland) followed by F1 and F2 ProTaper instruments and to compare these results with those obtained with a 25 .06 ProFile instrument (Dentsply Maillefer) followed by the Self-Adjusting File (SAF; ReDent, Ra'anana, Israel) using high resolution micro-computed tomography (CT) scanning. METHODS: Twenty-eight mandibular molar teeth with oval distal root canals were divided into 2 equal groups of 14 teeth each. The distal root canals were instrumented with ProTaper files up to an F2 instrument, the roots were subsequently filled, and the root filling was allowed to set fully. Removal of the root canal filling was performed with D1-D3 ProTaper retreatment files followed by F1 and F2 ProTaper instruments or with a 25 .06 ProFile followed by SAFs. Chloroform was used in both groups to assist in the removal of the root filling material. High-resolution micro-CT scans were used to measure the residual quantities of the root filling material after completion of the procedures. Statistical analysis was performed using the Wilcoxon test and the Student t test. RESULTS: The median root filling residue in the ProTaper group was 5.39% (interquartile range [IQR] = 4.71) of the original volume of the root canal filling. In the ProFile and SAF group, the median residue was 0.41% (IQR = 1.64, P < .001). An arbitrarily selected threshold of less than 0.5% residue was defined as "effectively cleaned," and 57% of the teeth treated with the ProFile and the SAF met this threshold, whereas none of the cases in the ProTaper group did. The ProFile and SAF procedure required less time than the ProTaper protocol. CONCLUSIONS: None of the retreatment methods rendered all of the canals completely free of all root filling residue. Under the conditions of this study, the ProFile and SAF procedure was more effective than the ProTaper procedure and left significantly less root filling residue in the root canal.

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The goal of endodontic treatment is to remove all the vital and necrotic tissues, microorganisms and microbial byproducts from root canal system. This goal can be achieved through chemical and mechanical debridement of root canals. This article narrates the specifics and requirements of the irrigation solutions. Sodium hypochlorite is proposed as the primary irrigant by virtue of its organic tissue dissolution capacity and broad antimicrobial properties. On the other hand, chelation solutions are recommended as auxiliary solutions to remove the smear layer or to hinder its formation on dentin surface. Thus, it's hoped that sealers and root canal fillers can penetrate to dentin tubules and obturate the canals hermetically. There are new studies on traditional irrigants especially on some irrigants that can replace sodium hypoclorite. This article reviews the new irrigants which can be used in future endodontic practice, and their advantages and limitations. Moreover, actions and interactions of recently used irrigants are adverted.

Socio-economic indicators and parents' level of education were not statistically significantly associated with the occurrence of traumatic dental injuries. Factors associated with increased risk of dental injuries in permanent teeth were age, gender, having an incisal overjet greater than 5mm and anterior open bite.

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Objectives: Cone-beam dental computerize tomography (CBCT), a noninvasive imaging method, was used to image the pulp-dentin complex. Pulp changes histologically with aging. While many studies have investigated the histological changes in pulp, few studies have focused on the changes in the shape of the root canals. This study evaluated the changes in the root canals with aging of central superior teeth using CBCT. Study Design: The study examined 100 non-carious maxillary central teeth. These teeth were divided into five groups according to the age of the patients: Group A:15-24, Group B: 25-34, Group C: 35-44, Group D: 45-54 and Group E: 55 years and older. CBCT was used to determine root length, and pulp width at the cervical, apical 1/2, and apical 1/3. Results: On comparing the groups using one-way analysis of variance (ANOVA), the root length did not differ (P > 0.05), while the pulp width at the cervical, apical 1/2, and apical 1/3 differed between the groups (P < 0.001). Conclusions: The pulp length did not change with aging, while the pulp width did change. CBCT can be used to determine the precise root length and width, to prevent iatrogenic exposure of the apex, complementing existing methods. This will improve the prediction of the prognosis of root canal treatment.