ENDO, 02/2013

Aim: This paper highlights a novel method of apical plug formation with a successful outcome. Methods: Clinical examination of the left maxillary central incisor revealed a draining intraoral sinus in the labial vestibule. A radiograph of the tooth 21 showed an obturated root canal with the presence of incomplete root formation and periapical radiolucency. The endodontic retreatment of tooth 21 was carried out under rubber dam isolation. Hydroxyapatite was condensed into the periapical bone defect along with obturation of the apical third of the root canal. The remaining canal space was obturated with thermoplasticised gutta-percha and the access preparation was restored using resin composite. Result: The 1 year-recall radiograph of the patient revealed a successful outcome and the patient was asymptomatic. Conclusion: Condensation of hydroxyapatite into the periapical bone defect, along with biomimetic obturation using hydroxyapatite of the apical root canal system is an innovative approach for the nonsurgical treatment of cases with incomplete root formation. Keywords: apexification, calcium hydroxide, hydroxyapatite, root canal therapy

Multiple angulated preoperative radiographs, careful exploration of the pulp chamber floor, together with the knowledge of canal morphology, are prerequisites for locating extra canals. Mandibular canines usually exhibit a single root and canal. The related literature reveals very few studies showing extra roots and canals in these teeth. This case report presents the successful root canal treatment of a rare occurrence in a mandibular canine of two roots and three canals. Keywords: aberrant root canal morphology, mandibular canine, multiple canals

Aim: The objective of this study was to evaluate which method, static or dynamic cyclic fatigue test, is the best to determine the number of cycles necessary to fracture rotary nickel-titanium endodontic instruments. Materials and methods: The static cyclic fatigue experiment used 10 instruments (Mtwo; VDW, Munich, Germany) that were statically freely rotated at 310 rpm in a metallic canal until fracturing. For the dynamic test, another set of 10 instruments was freely rotated at the same speed and in the same canal, but with a back and forth movement until they reached the fracture point. Results: The data were analysed by Student t test with a significance level set at 5% (P < 0.05). The dynamic test increased the lifespan of the instruments by 254%. Conclusions: Despite the fact that the static test complies with the no. 28 ANSI/ADA specifications, the dynamic cyclic fatigue test provides more reliable data regarding the lifespan determination of endodontic files and better represents the clinical practice. The present study presented a reliable way to standardise the test without human interference during the test. Keywords: apparatus and instruments, cyclic fatigue, dental instruments, endodontics, nickeltitanium alloy

Aim: To assess the variation in root canal anatomy of mandibular incisors in an Indian population, using cone beam CT (CBCT). Material and methods: A retrospective study of 130 Indian patients who underwent a CBCT ( Orthophos XG-3D, Sirona, Germany) scan for implants were selected for assessment of variation in the root canal anatomy in the mandibular incisors. The canal configurations were categorised according to Vertucci's classification. Two endodontists and an oral radiologist assessed the images, and the findings were recorded with respect to variation in anatomy, sex of the patient, side of the jaw, and type of incisor. Results: Vertucci type I and type III configurations were more prevalent in both mandibular central and lateral incisors. A percentage of 53.1% males and 46.9% females were included in this study. Males showed a 56.5% incidence of single root canal and 12.5% of double root canal. Females showed a 52.25% incidence of a single root canal and 8.75% showed a double root canal. The right side incisors showed an 83.85% likelihood of cases with single root canal and double root canal in 16.15% cases. The left side incisors showed an 83.45% likelihood of cases with single root canal, and double root canal in 16.55% of cases. On average 54.6%, 6.9%, and 38.45% of central incisors showed type I, II and III respectively. With respect to the lateral incisors, an average of 52.3%, 5.8%, 49.5% showed type I, II and III respectively. Conclusion: The CBCT scanner was able to detect these complex variations. This suggests that CBCT has potential as an auxiliary tool in the evaluation of mandibular incisors with complex canal morphology to improve the quality of root canal therapy. Keywords: CBCT, mandibular incisors, root canal

Aim: This in vitro study examined the effect of both early and late coronal flaring on the working length in curved root canals. Background: The objective of this study was to determine if canal length is altered as a result of coronal flaring (CF) in curved root canals. Study design: The conditions compared were combinations of (a) stainless steel hand files using Gates Glidden drills (SS) versus nickel-titanium rotary files (NiTi); and (b) early coronal flaring (flaring completed before working length determination) versus late coronal flaring (flaring completed after working length determination). Ninety canals of extracted first molars were selected, which were divided into three groups. Coronal flaring was accomplished for the SS group using Gates Glidden drills, and for the NiTi group using rotary ProTaper and HERO Shaper files (30 teeth per group). Working length was determined before coronal flaring, immediately after coronal flaring, and again after root canal preparation. Statistical analysis: Repeated measures of an analysis of variance (ANOVA) test and a Turkey's multiple post hoc test were used. Results: Results indicated that the working length decreased for all canals as a result of canal preparation. The mean decrease of working length was significantly greater for the SS group (-0.77 mm ± 0.42) than for the NiTi group (-0.33 mm ± 0.44). There was less change in working length in all groups when the initial working length was determined after coronal flaring. Conclusion: Working length in curved canals consistently decreased during the course of instrumentation. The clinician should keep this in mind for better treatment outcome. Keywords: pre-coronal flaring, rotary files, root canal preparation, working length

Dens invaginatus is an uncommon malformation of teeth due to infolding of the dental papilla during tooth development. Most often it is detected by chance on a radiograph. A deep foramen caecum is the first indication of this condition. Due to the tortuous lingual anatomy, it is possible for caries to develop without any clinically detectable lesion. As the enamel lining is thin and close to the pulp chamber, caries can cause pulp involvement rapidly. Maxillary lateral incisors are most commonly affected, followed by maxillary central incisors, premolars, canines and molars. This case report discusses the diagnosis and management of a case of Oehlers Type II dens invaginatus in a maxillary lateral incisor. The technique of proper cleaning and obturation of such complex canal systems, namely irrigation followed by ultrasonic agitation and use of sectional obturation together with thermoplasticised backfilling, is also discussed. Keywords: dens invaginatus, maxillary lateral incisor, thermoplasticised obturation, ultrasonic agitation

Aim: The purpose of this trial was to assess the clinical effects of cooling 2% lignocaine hydrochloride (with and without epinephrine) when used for inferior alveolar nerve block (IANB). Materials and methods: The trial was planned to have a 2 × 2 factorial design. One hundred patients were recruited and divided randomly into four groups of 25 each. Group I - lignocaine hydrochloride with epinephrine (room temperature); group II - lignocaine hydrochloride without epinephrine (room temperature); group III - lignocaine hydrochloride with epinephrine (refrigerated), and group IV - lignocaine hydrochloride without epinephrine (refrigerated). Electric pulp stimulations were used to assess the pulpal anaesthesia and the Heft-Parker visual analogue scale was used to assess the discomfort experienced during injection. The primary outcomes assessed were onset of action and duration of action. The secondary outcome assessed was pain on injection. The intervention assigned to each group was concealed from the patients, the senior endodontist and the principal investigator to maintain the blind trial. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U tests. Results: The results showed that pain at the injection site was least for group III followed by group IV. While comparing the onset of action, it was fastest for group III and slowest for group II. The longest duration of action was found in group III. Conclusion: Cooling of lignocaine hydrochloride (with and without epinephrine) resulted in lesser pain on injection, faster onset and longer duration of action in comparison with lignocaine hydrochloride (with and without epinephrine) at room temperature. Keywords: cool local anaesthetic, inferior alveolar nerve block, lignocaine hydrochloride, pulpal anaesthesia, randomised controlled trial

This case report presents an unusual occurrence of bilaterally symmetric maxillary first molars with four roots (two palatal roots) and four canals. This atypical root morphology was confirmed with cone beam computed tomography. Root canal treatment was performed for both first molars and coronal restoration was accomplished with resin composite and a full coverage porcelain crown. The clinician should always be aware of unusual root and canal morphology. The concurrent usage of the dental operating microscope and cone beam computed tomography, in addition to the thorough knowledge of the morphology of these teeth with careful clinical and radiological examination, is essential for successful clinical results. Keywords: cone beam computed tomography, dental operating microscope, maxillary first molar, root canal treatment, unusual root morphology

Aim: The presence of three root canals in the mesiobuccal root is an uncommon configuration in the maxillary first molar. The purpose of this paper is to present two cases that were diagnosed during an endodontic treatment. Materials and methods: Root canal therapy was performed with the aid of a dental operating microscope for better understanding of the complex anatomy. Careful analysis was given in the retreatment case, particularly looking for undetected canals that might have been a cause for endodontic failure. Results: The identification of two undetected root canals in a previously root canal therapy failure might be one of the reasons for the success of a reported case. The correct identification of an uncommon root canal configuration led to favourable results. Conclusions: The identification of unexpected anatomic configurations is mandatory. The failure to do so may lead to the failure of an endodontic therapy. Keywords: anatomy, molar, root canal therapy

Introduction: Various studies have reported variations in the number of canals and canal configurations in maxillary second premolars. Root canal configurations have been studied by various methods. The purpose of this study was to evaluate the different canal configurations and the incidence of two canals in the maxillary second premolar teeth of a north Indian population by using computed tomography. Materials and methods: One hundred completely formed, extracted non-carious maxillary second premolar teeth were collected and used in this study. The teeth were subjected to a high quality computed tomography (GE Light Speed Pro; GE Healthcare, Waukesha, WI, USA) scanner, which acquires forty slices per second. Each tooth was viewed in longitudinal as well as in transverse sections. The teeth were then grouped according to Vertucci's classification. Results and conclusions: This study showed that in almost 38% of the cases one root canal was found at the apex, and in 62% of cases two canals were found at the apex. The canal morphology was best visualised in the buccolingual plane. Seven types of canal configurations (type I, type II, type III, type IV, type V, type VI, type VII) were found. The most prevalent canal configuration was found to be type IV. Keywords: computed tomography, premolars, root canal anatomy, Vertucci's classification