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Anatomical variations of the root canal system of mandibular molars are common and often present challenges for endodontic treatment. In some cases, an additional root is located in the distolingual, radix entomolaris (RE), or more rarely in the buccal, radix paramolaris (RP). This case report illustrates rare nonsurgical retreatment of the complex root canal morphology of a RP and demonstrates the utility of cone-beam computed tomography (CBCT) and 3D printing in managing such a case. Underscored is the need for clinicians to understand the possible variations of root canal morphology of mandibular molars and the role CBCT imaging can play in addition to periapical radiographs in order to successfully treat a tooth with radix paramolaris.

Introduction The purpose of this study was to comprehensively assess by micro–computed tomographic imaging the anatomic features of distolingual (DL) roots and canals in mandibular first molars collected from 1 population. Methods One hundred two specimens were examined for the location and initial direction of the DL canal and the relationship between the distance of apical deviation and the angle of root curvature. Results All DL roots had only 1 canal. A new 7-category classification system is proposed for the DL roots of mandibular first molars. Most DL roots were type IV (28 teeth), type III (26 teeth), and type V (25 teeth). The average canal curvature in all root types was over 25°. There was a positive correlation between the angles of root and canal curvature for types II, IV, and V (P .05). In the buccolingual view, most DL roots were straight, whereas in the mesiodistal view the root curvature was close to the maximum value. The orifice of the DL canal was 4 times further from the line that bisects a line between the mesiobuccal and mesiolingual canal orifices than the distobuccal canal. The angle between the mesiobuccal-mesiolingual line and the horizontal projection of the coronal third of the DL canal on the pulp floor was 8.1° ± 10.0° and 6.1° ± 8.2° for teeth from the left and right side, respectively. The angle between the inserted simulated file and the cementoenamel junction was 57.9° ± 6.3°. Seventy-three percent of the DL canals had no constriction in the apical area. The DL canals were narrow and had a conical frustum-like shape with a 0.04 taper at the apical portion. Conclusions The novel classification of the DL roots helps to better understand the clinically challenging anatomy of the root and canal.

The aim of this randomized controlled study was to investigate changes in periodontal clinical parameters of individuals with generalized periodontitis with association of scaling and root planing (SRP) and multiple sessions of antimicrobial photodynamic therapy (aPDT). With a split-mouth model, patients received SRP alone in control side and SRP and three sessions of aPDT in all teeth of the test side with 0.01% methylene blue solution (Formula & Action, Sao Paulo, Brazil) and 5 min of pre-irradiation time. The irradiation was carried out with red laser source with Indium Gallium Aluminum Phosphide, with wavelength of 660 nm, output power of 100 mW, output energy of 9 J, fluence of 300 J/cm2, 90 s time, output spot of 3 mm2, irradiance of 3.33 W/cm2 (Laser Duo, MMOptics, Sao Paulo, Brazil), and in contact with the gum (mesiobuccal, distobuccal, mesiolingual, distolingual sites), in continuous wave mode. Clinical parameters measured at six sites per tooth (mesiobuccal, buccal, distobuccal, mesiolingual, lingual, distolingual) at baseline, 45 and 90 days after intervention, were probing depth (PD), clinical attachment level (CAL), plaque index (PI), and bleeding on probing (BOP). Twenty-four individuals with mean age of 52 years (± 12.7), 11 men and 13 women, were treated; 1626 sites received SRP and 1668 sites SRP and aPDT. PI reduced significantly in both groups. BOP had a higher reduction in the aPDT group (P > 0.001). Levels of PD and CAL in both sides improved, with no statistical difference between therapies. Although 3 sessions of aPDT associated with SRP provided no additional effect on PD and CAL levels after periodontal treatment, it showed a beneficial effect in gingival inflammation in a 3-month follow-up, which maybe can be attributed to several applications of aPDT after mechanical treatment of periodontitis.

Background: Pulp and root canal space is enigmatic and highly complex. Encountering rare has become a norm with the advancements in the technology of materials and types of equipment. The success of the root canal treatment depends on the effective removal of bacteria from the whole pulp space. A high percentage of the missed canal is reported for the failure of Endodontic therapy. Mandibular molars have complex root canal anatomy. Two roots with two canals in mesial root and one to two canals in distal root is a common occurrence. Nevertheless, the incidence of variation is relatively high, including separate distolingual, mesiobuccal, C-Shaped canals, isthmus, and additional canal in the mesial root. A wide range of the middle mesial canal occurrence, i.e., 3.1 to 46.1%, is reported in the world and 28.3% in North India. Aim: To identify the prevalence of the true middle mesial canal (MM) and configuration of Isthmi in the mesial root of the mandibular molar in the AP subpopulation of South India. Materials and methods: CBCT of 89 patients were randomly selected from the institutional database. Data entry was performed in Excel, and data analysis was done with the Statistical Package for Social Sciences (SPSS). Results: Four images (4.5%) revealed Middle Mesial canals with no statically significant occurrence. The frequency of isthmi in the mesial roots was 52.7%. This showed a considerable presence. Conclusion: MM canals are 4.5% in a subpopulation of Andhra Pradesh. Isthmuses are very common in the mesial roots of permanent mandibular molars. Isthmus about 58% was seen with Type II configuration that is the presence of two canals without a definite communication.

Introduction: Lateral throat form plays an important role in the success of lower complete denture as it affects its retention and stability. The length and thickness of lower dentures should be properly established in this region. Aim of this study is to evaluate the difference in the extension of lateral throat form between the patient's mouth and lower dentures. Materials and Methods: The lateral throat form was classified according to Neil's classification into Class I, Class II and Class III. The length of the lateral throat form was measured in the patient's mouth and in lower dentures with the help of UNC periodontal probe, and a comparison was made between them. Results: Among all the patients in this study, Neil's Class I lateral throat form was 53%, Class II was 37% and Class III was 10%. The average variation between the extent of lateral throat form intraorally and in lower denture at the anterior edge of the retromolar pad was 1.7 ± 1.75 mm in the right side and 2.5 ± 2.00 mm in the left side, whereas at the posterior edge of retromolar pad, it was 2.23 ± 1.92 mm in the right side and 3.06 ± 2.25 mm in the left side. Conclusions: The proportion of Neil's Class I was the highest followed by Class II and Class III was the lowest. The difference between the length of lateral throat form in the patient's mouth and in lower denture was statistically significant (P < 0.05).

According to Bacetti (1998) tooth rotation is defined as observable mesiolingual or distolingual intra-alveolar displacement of the tooth around its longitudinal axis.1 Tooth rotations cause difficulty in finishing fixed orthodontic treatment. In Begg’s technique rotation springs are used to correct tooth rotations. These springs are engaged into the vertical slot of the bracket. In case of preadjusted edgewise technique and edgewise technique brackets doesn’t have a vertical slot. So alternative methods are used to correct tooth rotations.2 Various methods include engaging NiTi arch wire into the bracket slot, off centering the bracket, using rotation wedges, creating a couple on the rotated tooth, by using ligature ties.3 The purpose of this case series is to discuss the biomechanics involved in rotation correction using bracket offsetting and couple. Keywords: Couple, Bracket offsetting.

Context: Studying in detail the root canal morphology specific to the Indian mandibular molars will help discern whether the root canal anatomy patterns resemble those reported internationally or are different from it. Aim: The aim is to study the root canal anatomy of Indian permanent mandibular first, second, and third molar teeth using a tooth clearing technique. Methods: The root canals of a total of 300 extracted Indian mandibular molars consisting of 100 first, second, and third molars each were accessed and injected with India ink, after which they were subjected to the clearing technique. Statistical Analysis: Data was analyzed using descriptive statistics for the computation of percentages using SPSS version 21. Results: Of the hundred first molars, 90% of teeth were two rooted with three canals, 79% had two apical foramina. 70% mesial roots of the three-rooted type showed Type I, whereas 100% distal roots and distolingual roots showed Type I Vertucci’s anatomy. About 70% mesial roots of two roots showed Type II and 90% distal canals showed Type I configuration. Among the second molars, five (5%) were single-rooted, ninety-one (91%) teeth were two rooted and four (4%) had three roots. Among the mandibular third molars, fifteen (15%) teeth had one root, sixty-three (63%) teeth had two roots, eighteen (18%) teeth had three roots, and four (4%) teeth had four roots. Conclusions: The root canal anatomic features of mandibular molars showed differences in the frequency of particular anatomic types as compared to mandibular molars from other racial backgrounds. Further comparative studies on inter-racial anatomic characteristics from various geographic locations would be beneficial.

A residual bone defect at the distal aspect of the adjacent second molar may occur after total removal of the lower third molar. Lower third molar coronectomy has been proved to be a safe alternative to total removal, but the extent of bone regeneration at the adjacent tooth after coronectomy is not well reported. The aim of this prospective study was to investigate the long-term bone regeneration at the distal aspect of the adjacent second molar after lower third molar coronectomy. Preoperative and postoperative cone beam computed tomography scans were measured to assess bone regeneration at the distobuccal (DB), mid-distal (MD), and distolingual (DL) aspects of the lower second molar. Forty-eight coronectomies in 37 patients (23 female) with a mean±standard deviation age of 29.1±7.2 years were assessed. The mean follow-up was 93.2±8.7 months. The mean bone level increase at DB, MD, and DL aspects was 3.2±1.6mm, 3.5±1.5mm, and 3.2±1.6mm, respectively; the bone levels were significantly higher than the preoperative measurements (P0.001). Age and impaction patterns were not factors affecting bone regeneration. Based on this study, it appears that coronectomy of the lower third molar brings favourable bone regeneration at the distal aspect of the adjacent second molar.

To objectively assess the expression and direction of artefacts in the vicinity of metal posts positioned in different mandibular regions. A human mandible had two sockets prepared—anterior and posterior regions—to accommodate a single-rooted tooth. Two CBCT units, Picasso Trio and OP300, were used. CBCT images of the tooth without metal post, and with silver-palladium, nickel-chromium, or cobalt-chromium posts (experimental groups) were individually acquired. Then, 8 lines of interest (LOIs) were determined around the root canal, in an axial reconstruction: 4 in orthogonal (buccal, lingual, mesial, and distal) directions, and 4 in oblique (mesiobuccal, distobuccal, mesiolingual, and distolingual) directions. The mean of gray values was measured for each LOI. For the OP300, in general, all experimental groups showed greater expression of hyperdense streaks in orthogonal LOIs and greater expression of hypodense streaks in oblique LOIs. For the Picasso Trio, for both mandibular regions, the buccal LOI showed greater expression of hypodense streaks; conversely, greater expression of hyperdense streaks was observed in the distal and distobuccal LOIs in the anterior region and in the mesiolingual LOI in the posterior region. The silver-palladium group showed significantly greater expression of beam hardening artefacts in the posterior region of the mandible, regardless of the CBCT unit (p < 0.05). The mandibular posterior region showed significantly lower gray values than the anterior region (p < 0.05). The expression and direction of artefacts produced in the vicinity of metal posts vary according to the mandibular region, composition of the post, and CBCT unit. The mapping of artefacts produced by metal posts reveals the root regions with greater expression of hypodense and hyperdense artefacts, which may contribute to recognizing regions more likely to mimic or hide root fracture lines.

Introduction: Measuring the gingival sulcus depth in children while their permanent teeth erupt is rather difficult especially if using reference norms for adults for a base. Aim: Assessment of the depth of the gingival sulcus during the period of tooth eruption in healthy children. Materials and methods: Thirty children were included in the study (age range 6 – 14 yrs). The children had good oral hygiene and no history of systemic disease. They were clinically examined – their dental statuses were taken, stages of permanent teeth eruption (up to 1/3 of the clinical crown, between 1/3 and 2/3, over 2/3, in occlusion contact), and their gingival sulcus depth was measured at 6 distovestibular, vestibular, mesiovestibular, mesiolingual, lingual, and distolingual sites using an electronic probe Parometer (Orange). It was concluded that the one with the highest value would be considered the maximum depth of the sulcus. Results: The gingival sulcus depth in fully erupted teeth is very similar to that in healthy adults (2.20 – 0.49 mm). The change of sulcus depth in incisors and canines has a variation of 1.5 mm, which at the end of eruption is close to those in adults. Maximum sulcus depth for molars, premolars and incisors was measured distovestibularly, and for canines – mesiovestibularly. Conclusion: At the various stages of eruption, the depth of the gingival sulcus plausibly decreases in all tooth types, and by the end of eruption it reaches a depth similar to that of the adult standard. Most indicative in regard to depth are the vestibular probing point.

Objective To describe root and canal morphology of mandibular first molars (MFMs) in a Yemeni population using cone-beam computed tomography (CBCT). Methods CBCT images of 500 right and left untreated MFMs with fully developed roots from 250 Yemenis (125 male and 125 female) comprised the sample size of this study. The following characteristics were recorded: (1) number of roots and their type and morphology, (2) number of canals orifices per root, (3) type of canal configuration and (4) primary variations in the morphology of the root and canal systems. Results 96.8% of MFMs are double-rooted. A third root was found in 3.2%, more in females than males. Mesial root was mainly ribbon-shaped (92.2%) and distal root was kidney-shaped in 56.2%. Two canals orifices were found in mesial root of 95.8% and one canal orifice was found in distal root of 96.4%. Vertucci type II canal configuration was the most frequent (57%), followed by type IV (35.6%) in mesial root. Type III canal configuration was the most prevalent (48.8%), followed by type I (41%) in distal root. Variant 3 represented the most common root and canal morphology (89.8%). Conclusion MFMs in Yemeni population are mainly two-rooted with 3.2% having a supernumerary distolingual root. Cross section of mesial root was mainly ribbon-shaped and distal root was kidney-shaped. Vertucci type II and III configurations were the higher incidence in mesial and distal roots, respectively. The presence of two canals in mesial root and one canal in distal root of MFMs with two separate roots (variant 3) was the most common morphology.

Introduction: Surgical removal of mandibular third molars is the most frequently performed minor oral surgical procedure. Aims: This study aims to evaluate its effect on periodontal status of second molars at 3 and 6 months' follow-up comparing extractions done by three different flap techniques. Settings and Design: Prospective randomized control clinical study. Subjects and Methods: Ninety medically healthy controls of both gender, aged between 18 and 50 years who underwent surgical removal of impacted mandibular third molars were divided into Group A, Group B and Group C wherein Bayonet flap, modified envelope flap and envelope flap was raised, respectively. Pocket depth at distobuccal and distolingual aspect of adjacent second molar was measured and compared for each group at preoperative as well as 3 and 6 months' follow-up. Statistical Analysis Used: ANOVA, paired t-test, and Tukey post hoc test using SPSS software. Results: There was no statistically significant difference found between pocket depths distal to second molars following impacted third molar extraction between three different flap groups. However, a significant reduction of pocket depth was noted from 3 to 6 months' follow-up for all three flap groups. Conclusions: Flap designs used for impacted third molar extractions do not contribute toward the alteration of periodontal health of second molars.

Background/purpose Minimally invasive endodontic approach become a research hotspot and may prevent the fracture of endodontically-treated teeth. This research aims to measure the coronal root canal morphology of permanent mandibular first molars in 3D and propose a new minimally invasive endodontic approach based on this measurement. Materials and methods Data of 136 permanent mandibular first molars were involved and reconstructed in 3D models with canals. Then, the morphology characteristics of the coronal root canal were measured. Results Overall, the distribution of root canal orifices was more centralized than other landmarks. The landmarks were located more mesiobuccally to the center of the occlusal plane of molars. Specifically, the measurements of the maximum curvature of coronal root canals in the axial direction were: in 3-canals 2-rooted teeth, the average angles of curvatures were 23°,25°,11° for mesiobuccal (MB), mesiolingual (ML) and distobuccal (DB) canals, respectively; in 4-canals 2-rooted teeth were 23°,25°,12°,16°for MB, ML, DB, and distolingual (DL) canals, respectively; in 4-canals 3-rooted teeth were 25°,27°,17°,39° for MB, ML, DB, and DL canals, respectively. The degrees of coronal root canal curvatures in the horizontal direction were: in 3-canals teeth, the average angles of curvatures were −1°,47°,-2° for MB, ML and DB canals, respectively; in 4-canals 2-rooted teeth were −4°,41°,-25°,48° for MB, ML, DB, and DL canals, respectively; in 4-canals 3-rooted teeth were −3°,33°,-43°,79° for MB, ML, DB, and DL canals, respectively. Conclusion The results of this study are similar to those previously obtained using CBCT and can help us design endodontic approaches.

Objectives To investigate tooth wear in young adults, intraoral scanning was used for digital monitoring of the mandibular first molar over 12 months. A possible influence of aetiological factors obtained by a questionnaire on tooth wear was investigated. Materials and methods A total of 109 participants (mean age at the start of the study: 21.0 ± 2.2 years) were included in this clinical study. At baseline (T0), an intraoral scan (Trios 3, 3Shape) of the study tooth (FDI # 36 or #46) was conducted. After a mean observation period of 373 ± 19 days, a second intraoral scan (T1, n = 94) of the same tooth as at T0 was performed and standard tessellation language datasets were superimposed with 3D analysis software (GOM Inspect). The occlusal surface of the study tooth was divided into 7 areas (5 cusps, 2 ridges) and maximum vertical substance loss was measured between T0 and T1 (n = 91). Three types of tooth wear were defined: cupping (C), facet (F) and combined cupping-facet (CF). Furthermore, a questionnaire on aetiological factors, such as dietary behaviour, was filled out at T0. Data were analysed with non-parametric tests (p Results Only one study tooth exhibited no tooth wear at T0, whereas 3 teeth showed C, 47 teeth F and 40 teeth CF. A progression of vertical substance loss for all three types was shown. Most affected were the mesiobuccal cusps (43, 38/47 µm; median, 95%CI) followed by distobuccal (36, 33/39 µm), mesiolingual (35, 26/40 µm), distolingual (34, 27/36 µm) and distal (31, 25/34 µm). On mesial and distal ridges, only F was detected with the lowest vertical substance loss of all areas (mesial ridge: 0, 0/0 µm; distal ridge: 0, 0/0 µm). An association between aetiological factors and loss values could not be shown. Conclusions All study teeth showed clear signs of wear, and after only 1 year, further substance loss was detectable. This result is of significance for young adults. Clinical relevance Since data of young adults regarding tooth wear are scarce, the results give a first idea of the amount of vertical loss per year and its relation to aetiological factors such as dietary behaviour. Therefore, further studies over a longer observation period are highly recommended.

Objective The aims of this study were (a) to evaluate the displacement and stress distribution in the maxillary dentition associated with the use of two different unilateral distalization appliances-unilateral zygoma gear (UZG) appliance and asymmetric headgear (AHG)-in non-growing patients; and (b) to assess the effects of fully erupted maxillary third molars on the distalization of the first molar with both appliances by using three-dimensional finite element analysis. Settings and sample population Two 3D models of the maxilla were created: one with third molars and one without. Next, two distalizing appliances (UZG and AHG) were added to each model to create four models. Materials and methods Distalization forces were applied, and the resultant displacements were recorded at the mesiobuccal and distolingual cusps and palatal root apex of each molar and the incisal edge root apex of the central incisors. The resulting von Mises stress distributions were evaluated. Results With the UZG, the first molar showed greater root distalization than the crown in the model with the third molar, whereas the model without the third molar showed distalization and distal tipping of the first molar. With the AHG, the first molar showed a large amount of distal tipping in the model without a third molar. However, this tipping was less than that in the model with third molars. Conclusion The presence of completely erupted third molars decreased the amount of uncontrolled distal tipping in both appliances. UZG can be considered as an effective option for maxillary molar distalization.

Background Understanding the anatomical morphology of the root canal is key for successful root canal treatment. The aims of this case presentation are to report a unique case of root canal treatment involving five root canals in the mandibular first premolar and to highlight the importance of variation in root canals of mandibular first premolars in clinical practice. Case presentation A 25-year-old male with intermittent pain in relation to the lower right posterior teeth over 3 weeks was diagnosed with symptomatic pulpitis in tooth #44. Four root canals were found, including mesiobuccal, distobuccal-1, distobuccal-2, and distolingual roots, and the Mtwo rotary system was used for root canal preparation. The four root canals were filled after 2 weeks, when a fifth canal was found, located in the buccal cavity. The fifth canal was confirmed to be the mesiolingual root canal by cone beam computed tomography (CBCT) and was found to be curved. After completion of the root canal filling, CBCT was performed, and a three-dimensional root canal image was reconstructed. After 1 week of observation, the tooth was repaired using composite resin filling. Conclusions This is the first case presentation of a fifth canal of the mandibular first premolar and advances our understanding of variations in the anatomy of the mandibular first premolar. This case report provides a reference for the treatment of mandibular first premolars.

Aim Placement of fixed space maintainer (FSM) and removable space maintainer (RSM) may increase the risk of gingivitis in children. This study aimed to assess the effect of using FSMs and RSMs on periodontal parameters in 6–12-year olds. Materials and methods This interventional prospective study was conducted on systemically healthy 6–12-year olds (mean age of 8 years) presenting at the Department of Pediatrics, Tehran University requiring space maintainers. The probing pocket depth (PPD), bleeding on probing (BOP), and gingival index (GI) were recorded at the baseline and 6 months after using space maintainers in the abutment teeth in patients with fixed space maintainers and in the tooth with the Adams clasp in children with removable space maintainers as well as the same teeth in the opposing jaw/quadrant as controls. Results A significant increase in PPD was noted in distolingual and mesiolingual sites at 6 months after placement of FSM (p < 0.05). This increase was not significant for RSM at any site. A significant increase in GI and BOP was also noted at 6 months after placement of FSM and RSM (p < 0.05). Caries index did not show a significant change in FSM but caries index significantly increased following the use of RSM. Conclusion BOP and GI increase following placement of FSM and RSM, and PPD increases in distolingual and mesiolingual areas of the banded tooth. How to cite this article Hosseinipour ZS, Poorzandpoush K, Heidari A, et al. Assessment of Periodontal Parameters Following the Use of Fixed and Removable Space Maintainers in 6–12-year Olds. Int J Clin Pediatr Dent 2019;12(5):405–409.

A wide array of anatomical variations present to dentists from time to time. The mandibular third molars are not far away in this context. Many a time, extraction remains the choice of treatment because of their most posterior location and unpredictable anatomy. In terms of anatomy, an extra distolingual root (radix entomolaris) poses a serious challenge, and it is very rare as well. Hence, the identification and management of radix entomolaris is an essential goal for the successful root canal treatment. The aim of this article is to present article the successful endodontic management of a mandibular third molar with three roots and four root canals.

Aim: This study aimed to analyze incidence of isthmus in human permanent mandibular first molar teeth using cone-beam computed tomographic imaging techniques in a South Indian population. Materials and Methods: Three hundred permanent mandibular first molar teeth were collected, cleaned, and stored in normal saline. They were divided into groups (GPs) I and II based on number of roots, and were further subdivided (right and left [RL] subgroups A and B for GP I; and RL subgroups C and D for GP-II). Samples were processed and isthmus incidence was evaluated by cone-beam tomography, compared, and statistically analyzed. Results: Overall in mandibular first molars, the isthmus incidence in mesial root was 97.2%, distal root was 39%, and distolingual root was 0%. There was no statistically significant difference between the right and left mandibular first molar teeth with regard to incidence of isthmus (P > 0.05). There was an incidence of type I (38.67%), type II (56.33%), type III (3%), and type IV (2%) isthmuses in mesial root and type I (12.33%), type II (16%), and type III (10.67%) in distal root. Conclusion: Incidence of isthmus was very high in the mesial root of the mandibular first molar and should be factored during nonsurgical and surgical endodontic treatment procedures to achieve successful treatment outcomes.

The high morphological complexity of premolars, has led to propose different techniques for successful endodontic therapy. The purpose of this report is to describe the ProTaper manual technique in a second mandibular premolar showing a high anatomical complexity. A patient of 19 years old co- mes to the clinic of endodontic in the Regional Hospi- tal (Temuco), diagnosed with irreversible pulpitis on tooth 35. Radiographic examination found that the tooth has two roots. For clinical suspicion of the presence of a third canal a Cone Beam computed tomography was requested, which confirmed the existence of a distolingual canal. Because it is a complex case, the increased taper endodontic technique was performed, allowing us to complete the endodontic therapy in less time and with less difficulty.

Background. Various occlusal schemes have been introduced over the years to enhance the stability, comfort, beauty and function of complete denture, of which lingualized, bilateral balanced and monoplane occlusions are the most recommended. The aim of this study was to compare the strain in mandibular denture-supporting structures in three different occlusal schemes. Methods. Two mandibular and maxillary models were simulated using epoxy resin, and strain gauges were embedded on each side of the mandible in mental foramen, buccal shelf and distolingual area. Strain values were measured in three occlusal schemes at centric occlusion protrusive and lateral movements. Data were analyzed with one-way and three-way ANOVA, followed by post-hoc Tukey tests. The significant level was set at 0.05. Results. The mean strain in denture-supporting area was lower in monoplane occlusion than the two other occlusal schemes, and the mean of values in the buccal shelf was higher than that of mental foramen and distolingual area. In all the three occlusal schemes, the mean strain values on the working side were higher than those on the non-working side during eccentric movements. Conclusion. Monoplane occlusal scheme imposed lower strain on denture-supporting area, with the buccal shelf being the primary strain-bearing area to tolerate more pressure than the rest of the denture-supporting areas. In terms of strain distribu-tion scheme, in all the three occlusal schemes, the working side received more strain than the non-working side during eccen-tric movements.

Docodon was the first described docodont, and has long featured prominently in the comparative and functional morphology of mammaliaform mandibles and teeth. We have now re-examined the dental and mandibular fossils of Docodon from Yale Quarry 9 at the Como Bluff site in the Late Jurassic Morrison Formation, using Computed Tomography (CT) scans and 3D image analyses. Our CT study revealed that some features used to distinguish the several Docodon “species” in historical studies many decades ago were based on incorrect manual restoration of mandibles, and on variable features of deciduous premolars, which are replaced in typical mammaliaform fashion. This supports a long-held notion that the multiple species of Docodon from the same quarry of the Morrison Formation are over-split and should be synonymized. We formally propose that the specimens examined in this study be synonymized under Docodon victor. Our new Occlusal Fingerprint Analysis (OFA) of Docodon molars supports the hypothesis that Docodon had a consistent dorso-posterior or palinal component in chewing in the disto-distolingual to distolingual direction. This helps to resolve the controversial historical alternative hypotheses postulated for tooth occlusion in the taxon. The Docodon occlusal pattern is likely a derived feature, evolved within Docodonta. A posterior component in the occlusal trajectory is a functional convergence of Docodon on unrelated traversodontid cynodonts.

Apical surgery on the separate distolingual (DL) root of a 3-rooted mandibular first molar is thought to be difficult because DL roots are always severely curved, small, and shorter than distobuccal (DB) roots, and they are located far from the buccal cortical bone. The purpose of this study was to use cone-beam computed tomographic images to investigate the apical surgery-related morphological characteristics of DL roots in a Chinese population.The screening process identified 83 subjects with 128 mandibular first molars with separate DL roots. The degree of root canal curvature was measured in the mesiodistal (MD) and buccolingual (BL) planes using the Schneider method. Distances were measured from the DL root apex to the buccal cortical bone, to the buccal cortical bone opposite the DB root apex, and to the buccal cortical bone opposite the mesiobuccal (MB) root apex. The lengths of the remaining DB, MB, and DL roots were measured after resection of 3 mm of the DL apical root. Angulations of the DL root canal were determined before and after DL apical root resection.The teeth were classified into 3 types: type I, straight in the MD and BL planes; type II, straight in the MD plane and curved in the BL plane; and type III, curved in the MD and BL planes. Only 5 molars (3.9%) were classified as type I, whereas 52 (40.6%) molars were type II and 71 (55.5%) molars were type III. The type I DL root has a significantly shorter length and longer distance from the DL root apex to the buccal cortical bone than type II and III roots (P .05). The distance from the DL root apex to the buccal cortical bone opposite the MB root apex is significantly longer than the distance to the buccal cortical bone opposite the DB root apex in types I and II (P .05), whereas the distance is nearly equal for type III. The angulations for root-end preparation of types II and III DL roots vary from 57.5° to 129.1° and from 55.8° to 128.1°, respectively.A new classification was proposed for DL roots in 3-rooted mandibular first molars based on the root canal curvature. Type I is unsuitable for apical surgery. Access to the type II DL root apex should be through the DB root apex, whereas access to the type III DL root apex through the MB root apex is more feasible. Apical surgery on types II and III DL roots may be accomplished when the depth of the root-end preparation is reasonably reduced, and fine and personalized angulated ultrasonic retro tips are used.

Introduction The purpose of this study was to examine the frequency and bilateral consistency of distolingual roots (DLRs) in permanent mandibular first molars (PMFMs) and root canal configurations in PMFPs (permanent mandibular first premolars) and to determine the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. Methods A total of 932 cone-beam computed tomographic images of PMFMs and PMFPs were collected from 233 patients. The frequency and bilateral consistency of DLRs in PMFMs along with root canal configurations (root number and canal number) of PMFPs were recorded and evaluated ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. Results The prevalence of PMFMs with DLRs was 24.7%, and the incidence of complicated root canal configurations of PMFPs was 26.6%. The incidence of complicated root canal configurations of PMFPs was 19.6% in the non-DLR group, 37.2% in the unilateral DLR group, and 44.7% in the bilateral DLR group. After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMFPs in the unilateral DLR and bilateral DLR groups compared with the non-DLR group were 2.472 (95% confidence interval, 1.434–4.263; P = .001) and 3.392 (95% confidence interval, 1.976–5.823; P Conclusions An increasing and corresponding trend between the presence of DLRs in PMFMs and complicated root canal configurations in PMFPs was noted in Taiwanese individuals. These results suggest that the clinicians should familiarize themselves with the anatomic variants of PMFMs and PMFPs before endodontic treatment.

The knowledge of variations in root canal morphology significantly affects the success of endodontic treatment. This article presents the endodontic management of a unique case of mandibular molar with an additional distolingual root with two canals and radix endomolaris which is quite uncommon. Mandibular molars can sometimes present a variation called radix endomolaris, wherein the tooth has an extra root attached to its lingual aspect. Accurate diagnosis and careful application of clinical endodontic skill can favorably alter the prognosis of treatment. Keyword: Radix Endomolaris.

Objectives This study was performed to assess the anatomy of mandibular first molars. Materials and methods In this in vivo study, cone-beam computed tomography (CBCT) volumes of 312 bilateral intact first mandibular molars from 156 patients (79 men and 77 women; average age, 35.6 ± 11.2 years) were investigated in terms of the direction of each canal's curvature in the buccolingual and mesiodistal dimensions (direction of the position of the apex in relation to the longitudinal axis of the root), the presence of an isthmus (a narrow, ribbon-shaped communication between 2 root canals) in 3 segments (0-2, 2-4, and 4-6 mm) from the apex), and the presence and number of accessory canals (smaller canals besides the main root canals, connecting the pulp to the periodontium). Data were analyzed statistically (α = 0.05). Results Mesiolingual canals were mostly buccally and distally inclined, while mesiobuccal and distolingual canals were mostly distally curved. Isthmuses were more common in younger patients (χ2 test, p 0.05). Conclusions The complex anatomy of these teeth deserves attention during non-surgical or surgical endodontic treatment. Around the apex, isthmuses might be more prevalent in younger and female individuals.

Background A knowledge regarding anatomical variants is important to achieve success in endodontic treatment. Root canal treatment of mandibular first premolars (PM1 s) is challenging due to the existence of numerous variations in canal configurations, including a C-shaped variant. We aim to determine the frequency and morphologic characteristics of non-single canals of mandibular first (PM1 s) and second (PM2 s) premolars in a Korean population using cone beam computed tomography (CBCT) and to evaluate correlations between non-single canals of PM1 s and other anatomical variants, such as distolingual roots (DLRs) in mandibular first molars (M1 s) and C-shaped canals in mandibular second molars (M2 s). Methods A total of 971 PM1 s and 997 PM2 s from 500 patients were examined in vivo by CBCT. Root canal configurations and C-shaped canals were determined in accordance with the Vertucci classification and Fan classification, respectively. The correlation between non-single canals in PM1 s and DLRs in M1 s was evaluated using logistic regression analysis. Results PM2 s typically had one root (99.89%) with one canal (98.4%). Among PM1 s with non-single canals (21.2%), Vertucci type V (10.9%) and C-shaped (3.7%) canals were prevalent. Among C-shaped PM1 canals, the majority were Vertucci type V (77.8%); a C-shaped configuration (C2) was predominant mostly at the middle and/or apical third of the root. After adjusting for other variables (i.e., sex, age, and side), C-shaped canals in PM1 s was significantly correlated with the presence of DLRs in M1 s (odds ratio = 2.616; 95% confidence interval, 1.257–5.443; p = 0.010). Conclusions The presence of C-shaped PM1 canals was positively related to the presence of DLRs in M1 s. Although C-shaped canals in PM1 s are difficult to distinguish, this finding could aid clinicians in predicting C-shaped canal configurations in PM1 s of patients who exhibit DLRs in M1 s.

A combined conventional and digital workflow is described to print a 3-dimensional complete-arch reduction guide. This was used to prepare guide planes with cross-arch parallelism in the distal of both maxillary first molars, the mesial of both maxillary first premolars, and the distolingual of both maxillary central incisors for a patient requiring a removable partial denture to replace missing bilateral maxillary lateral incisors and canines. The 3-dimensionally printed guide was placed on the remaining teeth in the arch and used as both a visual guide and a guide for tooth preparation.

BACKGROUND The follow-up of the peri-implant marginal bone loss is the most important criterion for the determination of implant success. PURPOSE The purpose of this study is to measure marginal bone loss using panoramic radiographic images (PRI) of patients treated using a mandibular, two implant-supported, locator-retained denture and to evaluate the compatibility of these findings with those of the finite element analysis (FEA). MATERIALS AND METHODS The PRI of patients who had a mandibular, two implant-supported, locator-retained denture were assessed, and the mesial and distal marginal bone loss of both right- and left-sided implants was measured. Mandibular and maxillary models, which have the features of bilateral balanced occlusion, were created. The surfaces of the generated models were converted in a computer-aided design model that could be transferred to the FEA software, and the forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for bilateral balanced occlusion. RESULTS The bone loss in the mesial and distal regions at the right- and left-sided implants was not statistically significant. Higher stresses were formed on the vestibular side under protrusive movement, on the lingual side under maximum intercuspation, on the distolingual side under left unilateral biting, and on the mesiolingual side under right unilateral biting in the FEA. CONCLUSION According to FEA, peri-implant bone resorption may be higher in the buccal and palatal regions, implying that panoramic radiographs can be misleading in understanding the amount of peri-implant bone resorption.

Aim To measure the coronal root canal morphology of permanent mandibular first molars using 3D coordinates for more precise conservative endodontic cavity preparation. Methodology In total, 57 cone beam computed tomography (CBCT) images of sound mandibular molars with fully formed apices without previous endodontic treatment were taken from 33 patients aged 16 to 75 years. The CBCT machine (MCT-1[EX-2F], J. Morita Manufacturing Corp, Kyoto, Japan) provided 14-bit greyscale images with the voxel size of 0.125 mm. All images were taken at 80 kV and 5.0 mA, with a 17-s exposure time, which were then reconstructed in 3D models and viewed by an endodontist. The gender of the patients and the tooth position, and number of root canals, were recorded. The landmarks of coronal root canals were determined, then the distribution of landmarks, maximum curvature in the axial direction and curvature directions in the horizontal direction of coronal root canals were measured. Distributions of landmarks were analysed using a spatial statistics method. Data about curvature were compared using a t test. Results Overall, the distribution of root canal orifices and the centre of the canal primary curve were more centralized than other landmarks. The landmarks were located more mesiobuccally to the centre of the occlusal plane of mandibular first molars. Specifically, the measurements of the maximum curvature of coronal root canals in the axial direction were as follows: in 3-canal teeth, the average angles of curvatures were 22°,23°,15° for mesiobuccal (MB), mesiolingual (ML) and distobuccal (DB) canals, respectively; in 4-canal teeth, the average angles of curvatures were 24°,26°,15°,22°for MB, ML, DB and distolingual (DL) canals, respectively. The degrees of coronal root canal curvatures in the horizontal direction were as follows: in 3-canal teeth, the average angles of curvatures were -8°,47°,-2° for MB, ML and DB canals, respectively; in 4-canals teeth, the average angles were -11°,50°,-28°,45° for MB, ML, DB and DL canals, respectively. Statistically, there was no reliable side or sex difference in any of the measurements (P > 0.05). Conclusions In permanent two-rooted mandibular first molars, the coronal canals clustered in the direction of the mesiobuccal side of the occlusal surface of the teeth.

Multituberculata from the Lower Cretaceous (Barremian–Aptian) Balve locality in Germany are represented by two taxa, the pinheirodontid Bructerodon alatus gen. et sp. nov. and the eobaatarid Cheruscodon balvensis gen. et sp. nov. Bructerodon alatus gen. et sp. nov. is known from an upper premolar (P5) and an upper molar (M1) with a distinct distolingual wing showing three cusps. Cheruscodon balvensis gen. et sp. nov. is represented by a dentary fragment with p4 and isolated teeth (P1, p4, m2). The new taxon is similar to other eobaatarids by its small single-rooted p2, double-routed p3, p4 with a single distolabial cusp, and mesio–distally asymmetric lower molars. It differs from most other eobaatarids by a larger number of serrations (11) and a larger distolabial cusp on p4. Cheruscodon gen. nov. is similar to Arginbaatar from the Lower Cretaceous of Mongolia in having the roots of p4 exposed above the alveolar border and a mesially curved distal root of p4.

Aim: This study aims to analyze root canal configuration of human permanent mandibular first molars of an indo-Dravidian population based in southern India. Materials and Methods: A total of 1147 mandibular first permanent molars were collected, cleansed, and stored. The number of roots was recorded, access preparations made, pattern of orifices recorded after pulpal floor debridement, dye injected into the canals using apical negative pressure and subjected to a clearing technique. They were then analyzed using a stereo microscope and the canal configurations recorded (Vertucci). The number of roots, the pattern of orifices and canal configuration were recorded. Results: The pattern of orifices was triangular (87.9%), rectangular (8.5%), C-shaped (3.0%), and two orifice pattern (0.6%). About 95.6% of teeth had two roots, and 4.4% had three roots. The most common canal system configuration in mesial root was Vertucci type IV (52.3%), followed by type II (35%). Root canal configuration of the distal root revealed type I configuration in 62.7%, followed by types II (14.5%) and IV (12.4%). The distolingual root had a type I configuration. Conclusion: Awareness of canal configuration, adequate clinical skills, use of specialized techniques of diagnosis, debridement and obturation will pave the way for successful treatment outcomes.

Background: Mandibular first molars typically have two roots but sometimes a supernumerary root presents distolingually called as radix entomolaris (RE). Aim: The present study evaluated the prevalence of permanent mandibular first molars featuring a distolingual root in Haryana (North India). Materials and Methods: Five hundred patients possessing bilateral mandibular first molars were selected for this study. The intraoral periapical radiographs were taken. The radiographs of these patients were evaluated under optimal conditions. A total of 1000 mandibular first molars were screened, and the incidence of three-rooted mandibular first molars, RE and the correlation between left and right side occurrence and between either gender were recorded. Statistical Analysis: The binary logistic regression test and Pearson's Chi-square test were used for statistical analysis. Results: The prevalence of three-rooted permanent mandibular first molars was 13% of the patients examined and 8.3% of the teeth examined. There was no statistically significant difference between gender and side of occurrence ( P ≥ 0.05). The bilateral incidence of a symmetric distribution was 27.6 (18/65) among the RE teeth examined. Conclusion: RE is considered as an Asiatic trait. The occurrence of this macrostructure in the Haryana (North India) population was found to be 13%. The clinician must thoroughly examine the radiographs before the initiation of endodontic therapy.

Knowledge about the possible existence and the racial prevalence is mandatory for successful endodontic treatment of cases ofRadix Entomolaris (RE). Factors such as an extra cusp usually buccal (protostylid), prominent distolingual lobe, complexity of the external contour of the furcation and convexity in the cervical region help to diagnose the presence of an RE. Radiographically, double periodontal ligament images or outline of the distal root contour can hint the presence of an RE. An angled radiograph (25-30°) can be more useful in this regard. Three-dimensional imaging techniques based on computed tomography (CT) and cone beam computed tomography (CBCT) have been able to predict the exact morphology of an RE non- invasively. This is a case report of a successful endodontic treatment of an 11 years old female patient with

The objective of this study was to evaluate the success rate of intraligamentary injections (ILI) using a two- or four-site injection technique. One hundred and fifty-one mandibular molars diagnosed with asymptomatic irreversible pulpitis received ILI at the mesiobuccal and distobuccal aspects of the roots. Patients who experienced pain when the access cavity was performed received additional supplemental ILI in the mesiolingual and distolingual aspects. Pulpal anaesthesia was considered successful when complete analgesia was achieved. The data were analysed by means of the Fisher's exact and Pearson's chi-square tests. IL anaesthesia was successful for 92.1% of the teeth. Forty-eight teeth (31.8%) were sufficiently anaesthetised using the two-site ILI and 91 teeth (60.3%) following supplemental IL anaesthesia in two more sites. The results of this study indicate that the use of four-site IL injections as a primary anaesthetic technique may be considered a favourable alternative to the common IANB.

Objectives: To develop a method to clinically identify the position of the lingual nerve within the lingual tissue in the third molar region by electro-stimulation. Methods: Following ethical committee approval a cross-sectional study was performed in 20 healthy participants. A proprietary Electric Pulp Tester (EPT) was used intra-orally to stimulate the lingual nerve and, to identify the vertical position of the lingual nerve, measurements were taken when subjects felt a projected tingling sensation in the tongue as the stimulation probe was placed directly over the nerve. The nerve location was investigated in three positions in relation to the third molar: Point A at the retromolar pad; Point C at the distolingual attached gingivae of the erupted lower second molar and; Point B at the midline of the erupted third molar (or when the third molar was unerupted, midway between Points A & C). Results: Out of 20 participants 18 (90%) were able to identify the projected tingling sensation on the tongue upon stimulating the nerve, allowing the nerve position to be identified. The mean vertical height of the lingual nerve relative to the third molar was 10.5, 10.75 and 12.5 mm for positions A, B and C respectively. The sensation related to nerve stimulation was well accepted by participants with minimal adverse events. Conclusion: We have demonstrated that stimulation of the lingual nerve with an EPT can clinically identify the position of the lingual nerve in situ. This technique may be useful for the clinical determination of lingual nerve position prior to third molar surgery. Keywords: Lingual nerve, Electric pulp tester, Anatomy, Extraction, Mapping

Aim: The aim of the study was to evaluate the anatomical variations of the roots and root canal system, and to determine the symmetry between right and left sides of mandibular first permanent molars in Saudi Arabian population using images derived from cone beam computed tomography (CBCT) scans. Methods: The CBCT scans (with the following parameters: FOV 170 × 120 mm, 90 Kv, 5–8 mA, 17.5 s exposure time and 0.25 mm voxel size) were retrieved from the database and axial, coronal and sagittal sections of mandibular first molars were examined. The number of roots, canals and type of canal configuration based on Vertucci’s classification were recorded. Bilateral symmetry between right and left side of the same individuals and differences between genders were investigated. Results: Out of 174 mandibular first molars, 97.1% were two rooted and 2.9% were three rooted (distolingual root). In regards to the number of canals, 73% had three, 25.3% had four and 1.7% had two root canals. In teeth with four root canals, 90.9% of the extra canal was in the distal root, while 9.1% in the extra distolingual root. The most common canal configuration in mesial and distal root were type IV (64.9%) and type I (77%), respectively. Symmetrical analysis revealed 100% symmetry in number of roots and 56.4% in number of canals between right and left teeth in the same individual. Conclusions: Within the limitation of this study, wide range of canals configurations were noted in mandibular first molars among the Saudi Arabian population. The prevalence of three rooted mandibular first molars was relatively low. Three canals were most commonly seen in mandibular first molars. Bilateral symmetry was varied in number of canals and canals configurations, which could be of clinical significance while performing root canal treatment on both side mandibular first permanent molars. Keywords: Cone beam computed tomography, Mandibular first molar, Root canal, Saudi Arabian

Objectives This study aimed to investigate the prevalence of a separate distolingual root and to measure the thickness of the buccal cortical bone in mandibular first molars in Koreans using cone-beam computed tomography (CBCT) images. Materials and Methods High-quality CBCT data from 432 patients were analyzed in this study. The prevalence of a separate distolingual root of the mandibular first molar was investigated. The distance from the distobuccal and distolingual root apices to the outer surface of the buccal cortical bone was measured. We also evaluated the thickness of the buccal cortical bone. Results The prevalence of a separate distolingual root (2 separate distal roots with 1 canal in each root; 2R2C) was 23.26%. In mandibular first molars with 2R2C, the distance from the distobuccal root apex to the outer surface of the buccal cortical bone was 5.51 mm. Furthermore, the distance from the distolingual root apex to the outer surface of the buccal cortical bone was 12.09 mm. In mandibular first molars with 2R2C morphology, the thickness of the buccal cortical bone at the distobuccal root apex of the mandibular first molar was 3.30 mm. The buccal cortical bone at the distobuccal root apex was significantly thicker in the right side (3.38 mm) than the left side (3.09 mm) (p < 0.05). Conclusions A separate distolingual root is not rare in mandibular first molars in the Korean population. Anatomic and morphologic knowledge of the mandibular first molar can be useful in treatment planning, including surgical endodontic treatment.

Introduction The purpose of this study was to determine the position of the apical foramen (AF) in relation to root surfaces of human permanent teeth using cone-beam computed tomographic (CBCT) imaging and novel advanced imaging analysis software (e-Vol DX; CDT Software, Bauru, SP, Brazil). Methods The AF position was determined on CBCT scans viewed and analyzed using e-Vol DX of 1400 teeth (422 patients) according to the root surface as follows: buccal, mesiobuccal, mesial, mesiolingual/palatal, lingual/palatal, distolingual/palatal, distal, distobuccal, and central. Categoric variables were described as frequencies and percentages. Frequencies were reported with their confidence intervals (95%). Categoric variables were analyzed using the chi-square test with Yates correction. The level of significance was set at α = 0.05. Results The most frequent AF position in maxillary anterior teeth was central (46%–60%). The AF in mandibular central incisors was buccal in 44% of the cases. In maxillary first and second premolars, 39.98% and 42.56% of all AFs were central. In maxillary first and second molars, 46.12% and 57.49% of all AFs were central. The most frequent AF position in mandibular first and second premolars was central (42.85% and 50.98%). In mandibular first molars, 48.72% of all AFs were central. Conclusions The AF position in human permanent teeth was central in 48.95% and 42.08% of the maxillary and mandibular teeth. CBCT images analyzed by e-Vol DX can be used to determine the true anatomic position of the AF and can be a useful tool for the treatment planning of nonsurgical and surgical endodontic treatments.

Background The aim of this study was to evaluate the root canal morphology of mandibular first molars in a Chinese population by using cone-beam computed tomography (CBCT). Methods In this study, CBCT images of 900 mandibular first molars were evaluated for the following details: (1) number of roots, (2) number of apical foramina, (3) frequency distribution of root canal configurations defined in accordance with Vertucci’s classification, and (4) frequency of occurrence of middle mesial (MM) canal. Results Overall, 74.9% of the evaluated mandibular first molars possessed two roots, and 55.4% exhibited three apical foramina. The evaluated teeth exhibited a relatively high prevalence of type IV canals in mesial (M) roots (76.8%) and type I canals in the distal (D) (79.4%), distobuccal (DB) (98.7%), and distolingual (DL) (100%) roots. There were no significant differences in the number of roots, incidence of apical foramina, or distribution of different canal configurations of mandibular first molars between men and women (P > 0.05). 1.9% of mandibular first molars possessed three mesial canals, and the highest frequency of occurrence of MM canals (4.1%) was among Chinese people below the age of 30 years. Conclusions CBCT scanning facilitates identification of the root canal system. In order to increase the success rate of treatment, it is important to obtain information about the variable morphology of root canals before endodontic treatment. Trial registration TJSKE20160412. Registered 12 April 2016.

The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present. Objectives: To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT. Material and Methods: CBCT images of 116 patients were reviewed to determine the prevalence of three-rooted first mandibular molars in a Brazilian subpopulation. Furthermore, with the use of micro-CT, 55 extracted three-rooted mandibular first molars were scanned and reconstructed to assess root length, distance between canal orifices, apical diameter, Vertucci's classification, presence of apical delta, number of foramina and furcations, lateral and accessory canals. The distance between the orifice on the pulp chamber floor and the beginning of the curvature and the angle of canal curvature were analyzed in the distolingual root. Data were compared using the Kruskal-Wallis test (α=0.05). Results: The prevalence of three-rooted mandibular first molars was of 2.58%. Mesial roots showed complex distribution of the root canal system in comparison to the distal roots. The median of major diameters of mesiobuccal, mesiolingual and single mesial canals were: 0.34, 0.41 and 0.60 mm, respectively. The higher values of major diameters were found in the distobuccal canals (0.56 mm) and the lower diameters in the distolingual canals (0.29 mm). The lowest orifice distance was found between the mesial canals (MB-ML) and the highest distance between the distal root canals (DB-DL). Almost all distal roots had one root canal and one apical foramen with few accessory canals. Conclusions: Distolingual root generally has short length, severe curvature and a single root canal with low apical diameter.

Knowledge about the external and internal anatomy of the tooth is essential for successful dental practice. Anomalies in the tooth are often encountered which poses difficulties in dental treatments. As like any other tooth, mandibular first molars are also prone for anatomic malformations. One such anatomic variation is the presence of extra root distolingually. This distolingual root is called radix entomolaris (RE). The presence of an additional root can lead to difficulties during endodontic therapy. This article is a report of two cases describing the management of the first mandibular molars with an RE and clinical guidelines for its management.

Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris was detected clinically and radiographically with root canal configuration such as curves. An awareness and understanding of this unusual root and root canal morphology could contribute to the successful outcome of endodontic treatment. Conclusion: Root canal treatment on this case shows the lack of symptoms and normal radiographic presentation for two months follow-up.

Endodontic therapy of mandibular molars is a challenging task due to its varied root canal morphology. A mandibular first molar with additional buccal root (Radix paramolaris) and additional distolingual root (Radix Entomolaris) is an example of its varied anatomy. A successful management of atypical root canal configurations is an important aspect in determining the success rate of root canal therapy. The detail knowledge of the root morphology and canal anatomy allows the clinician for accurate location of the extra roots and canals and accordingly the refinement of the access cavity for the stress free entry of complex anatomy. Hence, for a successful root canal therapy, clinician must be aware of the external and internal anatomic variations .The aim of this clinical case report is to present and describe the unusual presence of two separate mesial roots and six root canals in mandibular first molar, detected during routine endodontic therapy.Kathmandu Univ Med J 2013; 11(4): 338-341

The present study describes a new juvenile hominin mandible and teeth and a new juvenile humerus from level V of the GP2 gallery of Cova del Gegant (Spain). The mandible (Gegant-5) preserves a portion of the right mandibular corpus from the M1 distally to the socket for the dc mesially, and the age at death is estimated as 4.5-5.0 years. Gegant-5 shows a single mental foramen located under the dm1/dm2 interdental septum, a relatively posterior placement compared with recent hominins of a similar developmental age. The mental foramen in Gegant-5 is also placed within the lower half of the mandibular corpus, as in the previously described late adolescent/adult mandible (Gegant-1) from this same Middle Paleolithic site. The Gegant-5 canine shows pronounced marginal ridges, a distal accessory ridge, and a pronounced distolingual tubercle. The P3 shows a lingually-displaced protoconid cusp tip and a distal accessory ridge. The P4 shows a slightly asymmetrical crown outline, a continuous transverse crest, a mesially placed metaconid cusp tip, a slight distal accessory ridge, and an accessory lingual cusp. The M1 shows a Y5 pattern of cusp contact and a well-developed and deep anterior fovea bounded posteriorly by a continuous midtrigonid crest. Gegant-4 is the distal portion of a left humerus from a juvenile estimated to be between 5 and 7 years old at death. The specimen shows thick cortical bone. Although fragmentary, the constellation of morphological and metric features indicates Neandertal affinities for these specimens. Their spatial proximity at the site and similar ages at death suggest these remains may represent a single individual. The addition of these new specimens brings the total number of Neandertal remains from the Cova del Gegant to five, and this site documents the clearest evidence for Neandertal fossils associated with Middle Paleolithic stone tools in this region of the Iberian Peninsula.

Aim To determine the root canal anatomy of mandibular second molars in a Korean population by analysing cone-beam computed tomography (CBCT) images. Methodology The CBCT images of 960 subjects were examined. The number and configuration of roots and canals were categorized according to Vertucci's and modified Melton's classifications. Results Of the 1920 mandibular second molars, 41% had one root, 58% had two roots, and

Introduction Three-rooted mandibular molars are 1 of the anatomic variations of mandibular molars. The location of the additional root is distolingual (radix entomolaris) or mesiobuccal (radix paramolaris). The purpose of this retrospective study was to assess the prevalence of 3- and 4-rooted mandibular first and second molars in the Israeli population and to classify them according to dimension, curvature, and location of separation from the main root. Methods A total of 1020 Israel patients' cone-beam computed tomographic scans were screened and evaluated. The incidence of 3- and 4-rooted first and second mandibular molars were recorded and analyzed. One thousand four hundred sixty-five mandibular second molars and 1,229 mandibular first molars were evaluated. Results The overall incidence of patients with 3-rooted mandibular first and second molars was 2.6% and 1.78%, respectively. The bilateral incidence of 3-rooted mandibular first and second molars was 26%. The incidence of 4-rooted mandibular second molar was 0.55%. No significant difference was found regarding sex or side of occurrence. Conclusions The occurrence of 3-rooted mandibular first molars in the Israeli population was rare, but clinicians should be aware of the special characteristic of this anatomic variation to modify accordingly the form of pulp chamber opening and choose appropriate instrumentation.