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Objective To study the distolingual space of mandibular molars in adult patients with different sagittal skeletal patterns, and to analyze the main bony anatomical sites that restrict molar distalization, in order to provide guidance for the treatment plan of molar distalization. Methods A total of 97 adult patients according to the inclusion criteria were selected from the Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University.The patients were divided into skeletal Class Ⅰ group(n=28), skeletal Class Ⅱ group(n=49) and skeletal Class Ⅲ group(n=20) according to the ANB angle. CBCT of the patients were imported into Dolphin software for 3D reconstruction. The width of the distal root of the second molar, the width of alveolar bone, the distance between the most convex point of the distal and lingual side of the distal root and the inneredge of the lingual cortex of the mandible were measured at the 2, 4, and 6 mm plane from the root furcation to the root apex. Statistical analysis was performed using SPSS 26.0 software, and univariate analysis of variance and LSD-t test were used to compare the difference. Results Root width was significantly narrower than alveolar bone width at all measurement planes(P

Introduction: Managing and treating severely resorbed ridges is a challenge for the dentist. Especially, in older geriatric patients who have this problem. Till now, the classification by Neil is well accepted by all for the distolingual vestibule region and lingual area. Materials and Methods: We studied 500 patients with the presence of mandibular second molar teeth aged 20–50 years. The mirror method and a special instrument were used to view the section of the distolingual aspect present in the lingual area as well as the oral cavity. Results: The records were seen and studied well for the class and lingual region present. Conclusion: The distolingual alveolar sulcus and lingual region in the mandible are a guide for the tray to be used. We recorded this region in the patients by our technique.

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).

Background/purpose: Most mandibular first molars have two roots. A major common variation of this tooth is the presence of a distolingual root, which is a common Mongoloid trait in certain populations. The aim of this article was to examine crown morphology in relation to the presence of the distolingual root. Materials and methods: Using dental casts, the crown morphology of 141 mandibular first molars from 71 Taiwanese individuals was analyzed. Periapical radiographs were used to detect distolingual roots. The length and width of the crowns and the crown units (i.e., trigonid and talonid) were measured. Ten intercuspal distances and five cusp angles were examined. Results: The buccolingual dimension of the crown and its ratio to the mesiodistal dimension were significantly increased in molars with a distolingual root, compared to molars without a distolingual root. Mesiodistal crown dimensions were similar; however, the crown unit dimensions were different: molars with a distolingual root had a shorter mesiodistal trigonid dimension but a longer talonid dimension, compared to molars without a distolingual root. The intercuspal distances from the three buccal cusps to the distolingual cusp were significantly longer, however, the distance between the mesiobuccal cusp and mesiolingual cusp was significantly shorter in teeth with a distolingual root than in teeth without a distolingual root. A significantly wider mesiolingual angle and narrower distolingual angle were observed in molars with a distolingual root, compared to molars without a distolingual root. Conclusion: The presence of a distolingual root significantly increased the buccolingual dimension of the crown and the location of distolingual cusp is significantly closer to the lingual side.

Background and Objectives: Persistent pain during the removal of mandibular third molars is often due to accessory nerve supply causing inadequate local anesthesia. This study aims to assess the requirement of routine distolingual infiltration anesthesia in addition to traditional inferior alveolar, lingual, and long buccal nerve block in mandibular third molar extractions. Methodology: Sixty patients requiring mandibular third molar extraction were randomly divided into two equal groups; Group A (Classic inferior alveolar, lingual, and buccal nerve block) and Group B (with an additional 0.2 ml distolingual infiltration). During various steps of the procedure, any complaint of pain was recorded and graded on a subjective Visual Analog Scale (VAS). Results: There was no significant difference between the two groups in regard to age (P = 0.666) and sex (P = 0.432). And also, no difference was found in angulation (P = 0.757), class (P = 0.417) and position (P = 1.000) of third molars. Mean VAS scores in Group B (0.153) were significantly lower (P = 0.004) than that of Group A (0.600). VAS scores during procedural steps were significantly lower in Group B during mucoperiosteal elevation (P = 0.050), bone guttering (P = 0.037), and tooth splitting (P = 0.052). Conclusion: Routine distolingual infiltration anesthesia, in addition to classic inferior alveolar, lingual, and long buccal nerve block, is recommended for the extraction of mandibular third molars.

The purpose of this study was to assess the prevalence of C-shaped canals in permanent mandibular second molars (SMs) and to determine whether its appearance was associated with the presence of distolingual root (DLR) in permanent mandibular first molars (FMs). Method and materials: Three hundred and eighty patients were qualified for evaluation of their FMs and SMs using cone beam computed tomography. The prevalence, distribution pattern, external root morphology, and the internal root canal anatomy of the examined molars were recorded and analyzed. Furthermore, the association between the root canal configurations of SMs and the appearance of DLR in FMs was also assessed. Results: The prevalence of SMs with C-shaped root canals was 44.7%. The most common root canal configuration type of the one-rooted SMs with C-shaped anatomy was C3 (45.6%), followed by C2 and C1. The frequency of C-shaped canals in SMs was 45.4% in Non-DLR group, 52.8% in unilateral DLR group, and 33.9% in bilateral DLR group, respectively. Moreover, the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was significantly lowered. Conclusion: The association between the presence of DLR in FMs and C-shaped canal configurations in neighboring SMs was surveyed, and the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was found to be significantly lowered. [ABSTRACT FROM AUTHOR]

Background/purpose Most mandibular first molars have two roots. A major common variation of this tooth is the presence of a distolingual root, which is a common Mongoloid trait in certain populations. The aim of this article was to examine crown morphology in relation to the presence of the distolingual root. Materials and methods Using dental casts, the crown morphology of 141 mandibular first molars from 71 Taiwanese individuals was analyzed. Periapical radiographs were used to detect distolingual roots. The length and width of the crowns and the crown units (i.e., trigonid and talonid) were measured. Ten intercuspal distances and five cusp angles were examined. Results The buccolingual dimension of the crown and its ratio to the mesiodistal dimension were significantly increased in molars with a distolingual root, compared to molars without a distolingual root. Mesiodistal crown dimensions were similar; however, the crown unit dimensions were different: molars with a distolingual root had a shorter mesiodistal trigonid dimension but a longer talonid dimension, compared to molars without a distolingual root. The intercuspal distances from the three buccal cusps to the distolingual cusp were significantly longer, however, the distance between the mesiobuccal cusp and mesiolingual cusp was significantly shorter in teeth with a distolingual root than in teeth without a distolingual root. A significantly wider mesiolingual angle and narrower distolingual angle were observed in molars with a distolingual root, compared to molars without a distolingual root. Conclusion The presence of a distolingual root significantly increased the buccolingual dimension of the crown and the location of distolingual cusp is significantly closer to the lingual side. [ABSTRACT FROM AUTHOR]

Objective To investigate and analyze the root and root canal morphology of mandibular first molars (MFMs) in the Tibetan population using cone-beam computed tomography (CBCT) and to provide references for clinical root canal treatment in the Tibetan population. Methods This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT imaging data of 300 mandibular first molars from 300 Tibetan patients were included. Patient age, the number of roots in mandibular first molars were recorded. The morphology and incidence of mesial root and mesial root canals and the morphology and incidence of distal root and distal root canals were statistically analyzed by Vertucci classification. Results There were 198 double-root teeth and 102 three-root teeth in the 300 mandibular first permanent molars. Among the three-rooted molars, 1 case had mesiolingual roots, and the rest had distolingual roots. The incidence rate of the distolingual root was 33.7%(101/300). The most common root canal configuration was Vertucci Ⅳ 65.7% (197/300), followed by Vertucci Ⅱ 20.3% (61/300) in the mesial roots. The overall incidence of middle mesial canals (MMCs) was 6% (18/300), with the highest incidence of MMCs in the 20-40 year-old group at 9% (9/100). The distal roots canals of single-distal-rooted mandibular first molars were mainly Vertucci Ⅰ 66.8% (133/199), followed by Vertucci Ⅱ 14.6% (29/199) and Vertucci Ⅳ 11.6% (23/199). For the mandibular first permanent molars with two distal roots, 96% (97/101) of the distal buccal roots and 100% (101/101) of the distal lingual roots were Vertucci Ⅰ root canals. Conclusion The root and root canal morphology of mandibular first permanent molars in a Tibetan population is complex and variable. Approximately one-third of patients have distolingual roots, and clinicians should carefully explore the root canals under the guidance of CBCT.

Objectives: The purpose of this study was to assess the prevalence of C-shaped canals in permanent mandibular second molars (SMs) and to determine whether its appearance was associated with the presence of distolingual root (DLR) in permanent mandibular first molars (FMs)., Method and Materials: Three hundred and eighty patients were qualified for evaluation of their FMs and SMs using cone beam computed tomography. The prevalence, distribution pattern, external root morphology, and the internal root canal anatomy of the examined molars were recorded and analyzed. Furthermore, the association between the root canal configurations of SMs and the appearance of DLR in FMs was also assessed., Results: The prevalence of SMs with C-shaped root canals was 44.7%. The most common root canal configuration type of the one-rooted SMs with C-shaped anatomy was C3 (45.6%), followed by C2 and C1. The frequency of C-shaped canals in SMs was 45.4% in Non-DLR group, 52.8% in unilateral DLR group, and 33.9% in bilateral DLR group, respectively. Moreover, the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was significantly lowered., Conclusion: The association between the presence of DLR in FMs and C-shaped canal configurations in neighboring SMs was surveyed, and the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was found to be significantly lowered.

Objective. To detect presence of MB2 canal in maxillary molars and distolingual canal in mandibular molars by Dental CT. Material and Methods. A retrospective study of 100 Dental CTs was done. Axial and paraxial images obtained were used to assess the presence of MB2 canal in maxillary molars and distolingual canal in mandibular molars. Results. The youngest patient was of 11 years while the eldest patient was of 77 years. Males were 58 in number and females were 42 in number. MB2 canals were present in 57 patients and distolingual canal was present in 18 patients. Maximum MB2 canals were present in age group between 51 and 60 years, while distolingual canals were present in age group of 21–30 years. Conclusion. Dental CT allows adequate visualization of variation in root canal morphology and can be important diagnostic tool for successful endodontic therapy.

Background and Aim: Amongst the various calcified structures in the human body, teeth have gained lot of popularity in estimating the sex of an individual as they are highly resistant to destruction and decomposition. The aim of this study was to determine the diagnostic analysis of mesiobuccal and distolingual dimensions of canine teeth in determining the gender in dentistry students in 2020. Material and Methods: This cross-sectional analytical study was performed on all dental students of the 5th semester (130 students) in the School of Dentistry of Islamic Azad University in 2019 and with all teeth except the third molar. Eligible for admission, an alginate mold was prepared from the upper and lower jaw arches and poured by dental yellow acetone plaster. Then, mesiodistal and buccolingual dimensions of permanent canine teeth were recorded using digital caliper. Data were analyzed by t-test. Result: In general, the mean age of students was 23.97±1.43 years (22-26 years). Out of 130 students, 72 (55.4%) were male and 58 (44.6%) were female. The mean mesiodistal and buccolingual dimensions of maxillary and mandibular canine teeth on both right and left sides in students were not significantly different (p <0.05). Conclusion: The analysis of dimensions of the permanent canine teeth has not any important role on determination gender. [ABSTRACT FROM AUTHOR]

Introduction: Odontogenic cutaneous sinus tracts are often misdiagnosed as lesions of non-odontogenic origin, leading to the treatment of patients with unnecessary and ineffective therapies. Sinus tracts of endodontic origin usually respond well to endodontic therapy. However, root canal treatment of mandibular molars with aberrant canal anatomy can be diagnostically and technically challenging. Herein we present a patient with a cutaneous odontogenic sinus tract in the right submandibular area. Case report: A 23-year-old Chinese female patient presented with a cutaneous odontogenic sinus tract that was initially misdiagnosed as a sebaceous cyst. The patient had undergone surgical excision and traditional Chinese medical therapy before endodontic consultation. With the aid of cone beam computed tomography (CBCT), it was confirmed that the causative factor of the cutaneous odontogenic sinus tract was chronic periapical periodontitis of the right mandibular second molar, which had a rare and curved distolingual root. The resolution of the sinus tract and apical healing was accomplished following nonsurgical root canal treatment. Conclusion: A dental aetiology must be included in the differential diagnosis of cutaneous sinus tracts in the neck and face. Elimination of odontogenic cutaneous sinus tract infection by endodontic therapy results in resolution of the sinus tract without surgical excision or systemic antibiotic therapy. This case report also indicates that CBCT imaging is useful for identifying the tooth involved, ascertaining the extent of surrounding bone destruction and accurately managing the aberrant canal morphology. [ABSTRACT FROM AUTHOR]

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., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported.