ENDO, 04/2018

Despite improved dental health, odontogenic infections originating from primary teeth are a frequent occurrence in daily clinical practice. Due to existing limitations in the implementation of endodontic treatment measures in childhood, the extraction of pain-causing or avital primary teeth is usually the procedure of choice. In the acute phase, the indication for antibiotic administration has often been discussed. With reference to the latest recommendations of the European Society of Endodontology (ESE; 2017)1 and the guidelines of the German Paul Ehrlich Society for Chemotherapy (PEG; 2018)2, the indication for the use of antibiotics is limited to odontogenic infections with systemic involvement, or where there is gross, rapid or diffuse spread of infection from neighbouring loci. Phenoxymethylpenicillin is the antibiotic of choice for primary teeth. In the case of permanent teeth or antibiotically pretreated odontogenic infection, the administration of amoxillin/clavulanic acid is preferred. Keywords: antibiotics, anti-infective therapy, apical periodontitis, dentogenic abscesses, odontogenic infections

Purpose: The aim of the present 1-year follow-up clinical study was to assess the healing of periapical lesions using volumetric analysis of cone beam computed tomography (CBCT) images, after either filling with platelet-rich fibrin (PRF) gel or filling with combined PRF gel and bioactive glass (PRF-BG). Materials and methods: Twelve patients were divided into two equal groups, six patients each, according to how the bony defect following periapical microsurgery was filled in maxillary anterior teeth with persisting periapical lesions in root canal treated teeth. Each patient was randomly assigned to either the PRF group or the PRF-BG group. Preoperative CBCT scans were taken for each patient for baseline volumetric analysis. All surgical procedures were performed under an operating microscope by a single operator. Postoperative CBCT scans were taken for each patient after 1 year for volumetric analysis. Wilcoxon signed rank test was used to show the effect of treatment. Kruskal-Wallis test was used to compare between the experimental groups (α = 0.05). Results: For both experimental groups significant reduction in volume resulted after treatment at P = 0.028 for PRF-BG group and P = 0.027 for PRF group. No significant difference was obtained between both experimental groups regarding percentage of change in volume at P = 0.132. Conclusion: The bioactive glass bone graft material did not give a significant difference when combined with PRF, so the use of PRF alone was sufficient to achieve periapical bone healing. Keywords: bioactive glass, endodontic microsurgery, platelet-rich fibrin, volumetric CBCT

Aim: This study assessed the ability of Reciproc R25 instruments in maintaining the original profile of root canal anatomy in simulated curved canals (SCC) after multiple uses. The bending resistance of R25 before and after each use was evaluated. Materials and methods: Fifty SCC manufactured in clear resin blocks and ten R25 instruments were used. Each instrument prepared five SCC with four reuses, without intermediate sterilization. The flexibility of each instrument was determined by 45-degree bending tests before and after reuse. Colour stereomicroscopic images from each block were taken at the same position before and after instrumentation. All image processing and data analysis were performed with Fiji program. Evaluation of canal transportation was obtained for straight and curved canal regions. Univariate analysis of variance and Tukey's test were used (P < 0.05). Results: No significant difference was observed in bending resistance before and after multiple uses (P > 0.05). There was no difference in canal transportation resulting from utilizing R25 instruments after five multiple uses (P > 0.05). However, canal transportation was more severe in curved canal portions than straight portions (P < 0.05). Conclusions: Bending resistance and the final shape obtained in plastic blocks following R25 instrument use did not vary significantly between the first and the fifth use. Keywords: dental instruments, root canal preparation, transportation

Objective: This study evaluated the effectiveness of the XP-endo Finisher file (XP) in cleaning root canals compared to passive ultrasonic irrigation (PUI). It also compared multiple activation techniques to a single form of activation. Furthermore, it analysed the sequence of using them in regard to cleaning efficiency. Materials and methods: The root canals of 60 extracted single human mandibular premolars were prepared using the NiTi iRaCe rotary system and then were randomly divided into five groups (n = 12) according to the final activation of irrigation technique as follows: CI (negative control), using conventional irrigation by an irrigating syringe; PUI, activation by PUI; XP, activation by XP; XP-PUI, activation by XP then PUI; PUI-XP, activation by PUI then XP. Specimens were scanned using a scanning electron microscope with a magnification of 2000×. Results: In all groups, the coronal and middle third demonstrated a significantly higher percentage of patent dentinal tubules compared to the apical third (P < 0.05). The XP showed a higher percentage of patent dentinal tubules than PUI in the apical area with a statistically insignificant difference (P > 0.05). The percentage of patent dentinal tubules was higher in multiple activation techniques as in XP-PUI and PUI-XP than with a single form of activation as with XP file alone or PUI alone (P < 0.05). There was no statistically significant difference between XP-PUI and PUI-XP (P > 0.05). Conclusions: Within the limitations of this study it can be concluded that no activation technique completely eliminated the smear layer. The XP was more effective in cleaning the apical area than PUI. Combining two methods of activation improved the cleanliness of the canals. Using either XP or PUI first had no effect on smear layer removal. Keywords: passive ultrasonic irrigation, scanning electron microscope, XP-endo Finisher file

Purpose: Gentlefile (GF) is a newly developed stainless steel rotary system claimed to have superior shaping ability compared to nickel-titanium (NiTi) rotary systems. The purpose of this study was to compare the incidence of the canal transportation and centring ability of ProTaper Next (PTN) and GF rotary systems. Methods and materials: Thirty-two mesiobuccal root canals of mandibular molars with an angle of curvature ranging from 25 to 45 degrees were randomly divided into two groups of 16 canals each according to the instrument used for preparation: PTN or GF files. Cone beam computed tomography (CBCT) was used before and after preparation of the samples to assess the amount of canal transportation and centring ability at 3, 6 and 9 mm from the apex. Data were scored and statistically analysed using independent t test. The significance level was set at P ≤ 0.05. Results: The GF system produced more canal transportation than the PTN system at 3 and 6 mm with a statistically significant difference (P ≤ 0.05), whereas at 9 mm there was no statistically significant difference between the two systems (P ≤ 0.05). PTN showed better centring ability than the GF at 6 mm and this difference was statistically significant (P ≤ 0.05). However, at 3 and 9 mm there was no significant difference between the two systems (P ≥ 0.05). Conclusions: Under the limitations of this study both systems produced canal transportation but the PTN system resulted in better root canal preparation with a lesser degree of canal transportation and better centring ability than the GF system. Keywords: canal transportation, centring ability, cone beam computed tomography, Gentlefile, ProTaper Next

The case of a 7-year-old boy presenting with a horizontal root fracture and concomitant avulsion of the coronal segment of a permanent maxillary central incisor is described. The coronal segment was replanted and splinted. As signs of infected pulp necrosis became apparent, one-visit apexification and root canal obturation of the coronal segment were performed. Complete resolution of the lateral lesion was observed, and the apical segment remained vital. One year after the dental trauma, there was clinical and radiographic evidence for periodontal healing. The patient later underwent orthodontic treatment with successful movement of the replanted coronal segment. The reported case illustrates the capacity of healing of complex dental injuries such as root fractures with severe coronal dislocation. Appropriate endodontic management may ensure long-term retention of severely injured teeth. Keywords: MTA, root fracture, tooth avulsion, tooth injuries

Apical periodontitis rarely results in sensory impairment of the inferior alveolar nerve. This article describes the Vincent symptom and documents a clinical case of this neurological disorder, in which paraesthesia as well as hypaesthesia of the mental nerve were caused by apical periodontitis of a first mandibular molar. The healing process and the long-term results, 2 years following non-surgical root canal treatment, are presented. Keywords: apical extrusion, inferior alveolar nerve, paraesthesia, Vincent symptom