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Background: The mandibular second molars demonstrate variations on root and canal morphology. The aim of this study was to investigate all the root canal morphology of mandibular second molars and analyze the morphological variations in patients by gender and age in a Chinese population use CBCT imaging., Methods: Cone-beam computed tomographic images of 1200 bilateral mandibular second molars were obtained from 600 patients (300 females and 300 males) who required a preoperative assessment for implant surgery, surgical removal of impacted teeth, orthodontic treatment, surgery of maxillofacial tumour and cysts or LeFort I osteotomy. CBCT images were divided into 5 groups according to age: "15-24 years", "25-34 years", "35-44 years", "45-54 years" and "≥ 55 years"; and 2 groups by gender: "females" and "males". The following information were recorded: the number of roots and canals and their morphology, the frequency and configuration of C-shaped canals by gender, age and position (left and right). The chi-square test was used to analyse differences between groups. P value of < 0.05 was considered statistically significant., Results: Of the 1200 teeth, 61% had two separate roots located mesiodistally, 35.6% had one C-shaped root. The 45.3% teeth had three canals in two-rooted mandibular second molars. The mesial root showed a Vertucci type II configuration in 28.9% cases followed by type IV(24.4%). While the distal root showed a significant higher prevalence of type I configuration in 95.6%. In the examined 1200 teeth, 430 teeth (35.8%) had C-shaped root canals. The prevalence of C-shaped root canal systems was significantly higher in females (42.5%) than in males (29.1%) (P = 0.000), and did not differ with age (P = 0.126). The 80.4% C-shaped canals were bilateral (P = 0.000) and did not differ with side (left and right) (P = 0.758)., Conclusions: The most commonly observed root morphology for the mandibular second molars was 2 separate roots with three canals.The prevalence of C-shaped root canal is 35.8% and is more higher in females than in males., (© 2022. The Author(s).)

Objectives: Hypercementosis (HC) is an asymptomatic excessive cementum deposition at the dental root apex. There is a lack of research that determines the pattern and associated factors of HC in Saudi Arabia., Materials and Methods: A retrospective cross-sectional study was conducted on a random sample of 815 Orthopantomograms (OPGs) that was obtained from a total of 14003 female patients archived OPGs. The OPGs were retrieved from the Kodak Carestream-R4 database for the period between 2015 and 2017 at Taibah University Dental College and Hospital (TUDCH), Al-Madinah Al-Munawwarah, Saudi Arabia. Width and radiodensity of HC were measured and the distribution was calculated. Association between HC and factors including age and nationality were explored. Descriptive and inferential analyses were performed., Results: The mean/SD age of HC affected patients (9.8%) was 30.16 ± 13.1 years, of whom 55% were Saudis. The mean/SD width and radiodensity of the hypercementosed roots were 4.14 ± 1.2 mm and 119.86 ± 29.83, respectively. The mandibular teeth were more frequently associated with hypercementosis (65%) specifically first molars (47.5%), while the majority (64%) had a single unilateral distribution pattern. There was a non-significant association between nationality, age, and HC (P = 0.921, P = 0.633, respectively)., Conclusion: Hypercementosis observed in 9.8% of female patients attending TUDCH which was primarily unilateral and prominently confined to the mandibular teeth roots. The complication of teeth extraction among female patients in Almadinah region should be anticipated., Competing Interests: None

This study explores the morphological differences between the enamel-dentine junction (EDJ) of maxillary and mandibular molars of Neanderthals (n = 150) and recent modern humans (n = 106), and between an earlier Neanderthal sample (consisting of Pre-Eemian and Eemian Neanderthals dating to before 115 ka) and a later Neanderthal sample (consisting of Post-Eemian Neanderthals dating to after 115 ka). The EDJ was visualised by segmenting microtomographic scans of each molar. A geometric morphometric methodology compared the positioning of the dentine horns, the shape of the marginal ridge between the dentine horns, and the shape of the cervix. We also examined the manifestation of non-metric traits at the EDJ including the crista obliqua, cusp 5, and post-paracone tubercle. Furthermore, we report on additional morphological features including centrally placed dentine horn tips and twinned dentine horns. Our results indicate that EDJ morphology can discriminate with a high degree of reliability between Neanderthals and recent modern humans at every molar position, and discriminate between the earlier and the later Neanderthal samples at every molar position, except for the M 3 in shape space. The cervix in isolation can also discriminate between Neanderthals and recent modern humans, except at the M 3 in form space, and is effective at discriminating between the earlier and the later Neanderthal samples, except at the M 2 /M 2 in form space. In addition to demonstrating the taxonomic valence of the EDJ, our analysis reveals unique manifestations of dental traits in Neanderthals and expanded levels of trait variation that have implications for trait definitions and scoring., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The Middle Pleistocene represents a period of critical importance in human evolution, marked by encephalisation and dental reduction, and increasing diversification of temporally and spatially distributed hominin lineages in Africa, Asia and Europe. New specimens, especially from areas less well represented in the fossil record, can inform the debate on morphological changes to the skeleton and teeth and the phylogenetic course of human evolution during this period. The mandible from the cave of Mala Balanica, Serbia has recently been re-dated to at least 400 ka, and its well-preserved dentition presents an excellent opportunity to characterize molar crown morphology at this time period, and re-examine claims for a lack of Neandertal affinities in the specimen. In this study we employ microtomography to image the internal structure of the mandibular molars (focusing on the morphology of the enamel-dentine junction, or EDJ) of the BH-1 specimen and a comparative sample (n = 141) of Homo erectus sensu lato, Homo neanderthalensis, Pleistocene Homo sapiens, and recent H. sapiens. We quantitatively assess EDJ morphology using 3D geometric morphometrics and examine the expression of discrete dental traits at the dentine surface. We also compare third molar enamel thickness in BH-1 to those of H. neanderthalensis and both Pleistocene and recent H. sapiens, and document previously unreported morphology of the BH-1 premolar and molar roots. Our results highlight the reliability of the EDJ surface for classifying hominin taxa, indicate a primitive dental morphology for BH-1 molars, and confirm a general lack of derived Neandertal features for the Balanica individual. The plesiomorphic character of BH-1 is consistent with several competing models of Middle Pleistocene hominin evolution and provides an important regional and temporal example for reconstructing morphological changes in the mandible and teeth during this time period., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Despite increasing knowledge of the basic molecular aspects of bone formation and its regulation, the mechanisms of bone morphogenesis leading to a topologically specific shape remain unknown. The formation of the alveolar bone, which houses the dental primordia and later, the dental roots, may serve as a model to understand the formation of bone form in general. Thirty-eight heads of mice (C57 Bl/6J) ranging from stages E13-P20 were used to prepare histological serial sections. For each stage, virtual 3D-reconstructions were made in order to study the morphogenesis of the mandibular molar primordia concomitantly with their surrounding bone. Special focus was given to recording the remodeling pattern. It has been shown that, in early stages (E13, E14), bone formation is characterized by apposition only. In stage E15, the bony crypt around the dental primordia is remodeled mostly by resorption of bone. In stage E18, the bone remodeling pattern shows resorption all along the bony gutter, which houses the molar primordia. The medial and lateral margins are characterized by apposition. At birth (stage P0), a bony septum has begun to form between the primordium m1 and of m2, arising from both sides and characterized by pure apposition of bone. In stage P4, the crypts of m1 and m2, and also that of m3, show bone resorption inside, while the medial and lateral bony margins show apposition of bone throughout. Generally, during development, the bone gradually encapsulates the dental primordia, in such a way that the bone reaches over the dental primordia and leaves only a continuous longish opening of about 200μm width. The opening at the occlusal surface of m1, at the time of eruption, starting at stage P14, appears to have increased in size again. The distance between bone and dental primordium undergoes change during development. In erupted molars, it is around 100μm, during early developmental stages, it may be as less as 20μm. These data show the inevitability of bone remodeling., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

The Custom Alveolar Ridge Splitting (CARS) technique was recently reported as a less-invasive treatment option for augmentation of the maxillary anterior area in cases where alveolar width deficiency exists due to bone resorption and remodeling. This technique creates an intraosseous defect to improve success when horizontal ridge augmentation is attempted. The purpose of the present case report was to demonstrate implant placement in an atrophic posterior mandibular site using the CARS technique. This technique was used in the mandibular right second premolar area, followed by placement of a single implant. The restored implant showed stable soft and hard tissue outcomes at 6 months postloading. [ABSTRACT FROM AUTHOR]

Background: Two intra‐coronal preparation designs with varying extensions of cuspal coverage can perform differently regarding their fracture resistance against introral forces. Methods: Two materials (IPS e‐max CAD [EX], VITA ENAMIC [EN]), and two different preparation designs (EX‐D1), (EX‐D2), (EN‐D1), and (EN‐D2) were investigated to compare their fracture resistance. A total of 40 (n = 40) caries free human mandibular molars were used. All the prepared samples were scanned using CEREC Omnicam scanner and the preparations were checked by the software for any sharpness and undercuts before restoration designing and fabrication. All restorations were milled using Cerec MCXL 4.4 milling machine. Duo‐Link resin cement was used for cementation. After thermocycling and chewing simulation, all samples were loaded in the Universal testing machine in order to evaluate fracture resistance of all samples. Results: Fracture resistance testing revealed that e‐max CAD (2134 N) showed statistically significantly higher mean fracture resistance values than Vita Enamic (1728 N). On the other hand, there was no statistically significant difference between mean fracture resistances between the two tested designs. Conclusions: Within the confines of this investigation, it can be said that although preparation design had no appreciable impact on fracture resistance, the CAD/CAM ceramic material utilized did. Clinical Significance: When restoring compound cavitties indirectly; a conservative defect oriented approach should be used. Glass Ceramic are prefered as restorative material. [ABSTRACT FROM AUTHOR]

Background: This investigation compared the extent of external apical root resorption (EARR) in root-filled teeth (RFT) and their contralateral vital pulp teeth (VPT) counterparts during orthodontic treatment (OT) with clear aligner (CA) treatment or fixed appliance (FA) treatment. Methods: Sixty-six patients with similar baseline American Board of Orthodontics (ABO) discrepancy index scores were divided into two groups: 37 patients (21 females, 16 males; mean age 17.45 ± 2.67 years) in the FA group, and 29 patients (18 females, 11 males; mean age 18.33 ± 1.96 years) in the CA group. Digital panoramic radiographs captured pre- and post-OT were used to measure tooth lengths and root surface measurements in mandibular molars. EARR in both RFT and contralateral VPT was evaluated pre- and post-OT. Statistical analysis employed paired t-tests, independent t-tests, and analysis of covariance (ANCOVA) (p <.05). Results: All teeth exhibited varying degrees of EARR following OT. FA treatment resulted in significantly longer treatment duration (p <.05) and greater EARR compared to CA treatment (p <.05). Moreover, statistically significant differences in EARR were observed within both groups between RFT and VPT (p <.05). Conclusions: Comparison of pre- and post-OT radiographs revealed different degrees of EARR in all teeth. CA treatment resulted in less frequent and less severe EARR compared to FA treatment. RFT demonstrated greater resistance to EARR than VPT in both treatment groups. [ABSTRACT FROM AUTHOR]

Background: To investigate the anatomic features of the root furcation of permanent mandibular first molars. Methods: A total of 50 extracted mandibular first molars (25 two-rooted and 25 three-rooted) were collected and scanned using micro-computed tomography. The digital models of teeth and root canal systems were reconstructed three-dimensionally. The tooth models were displayed in parallel projection mode from buccal and distal views. Screenshots were captured and subsequently analyzed using Image-Pro Plus 6.0 software after calibration. The furcation angle, root trunk length, maximum depth and level of distal root concaves of mesial roots, and length of enamel projections were measured, and the furcation types (classified into type V, type U and type W) were detected. Statistical analysis was performed using the Shapiro-Wilk's test, one-way analysis of variance, Student's t-test and Chi-square test. Results: The mean furcation angle between the distobuccal (DB) and distolingual (DL) roots (in distal view) was the greatest (59.2°), whereas the furcation angle between the mesial and DL roots (in buccal view) was the smallest (25.4°) among the four furcation angles (all p < 0.05). Regarding the furcation types, bucco-lingual root trunk length, maximum depth and site of the distal root concavities, and enamel projection length, no significant differences were detected between the three- and two-rooted molar groups (all p > 0.05). The frequency of type V was the highest (54.0%), followed by type U (26.0%), and type W had the lowest occurrence rate (20.0%). The mean length of distal root trunk in the three-rooted mandibular molars was significantly greater than that of the buccal/lingual one (3.7 mm vs. 3.0 mm, p < 0.01). The maximum depth of the distal concavities of the mesial roots was on average 0.66 ± 0.19 mm, and the site was located at an average of 2.8 ± 1.3 mm below furcation. The mean length of buccal enamel projections was significantly longer than that of lingual ones (3.1 mm vs. 0.7 mm, p < 0.01). Conclusions: The furcation anatomy of the mandibular first molar is complex, and the presence of the DL root may further complicate its topography. A thorough understanding of these anatomic features is essential for successful periodontal treatment. [ABSTRACT FROM AUTHOR]

The presence of facial jewelry and medical devices within a radiographic field of view may promote the formation of artifacts that challenge diagnostic interpretation. The objective of this article is to describe a previously unreported radiographic anomaly produced by an oral piercing site below the lower lip. This unusual artifact masqueraded as a severe resorptive defect, dental caries, or cervical abfraction and occurred following removal of an extremely large labret below the lower lip and subsequent acquisition of a radiographic image. The radiolucency was ultimately attributed to an extensive aperture below the lower lip created by a series of sequentially larger soft tissue expanders. Clinicians should seek correlation of atypical radiographic presentations with soft tissue defects secondary to injury or intentional oral piercing. [ABSTRACT FROM AUTHOR]

BACKGROUND: Computer-assisted implant surgery can improve implantation accuracy, but the use of implant template in the posterior tooth area is limited for patients with small opening and small interocclusal distance. Therefore, the digital guide has been improved. OBJECTIVE: To study the effect of modified implant template on the accuracy of assisted implantation in missing second molars. METHODS: From July 2020 to July 2023, 40 patients who received digital guide plate implantation or free hand implantation to repair missing second molars were selected from First Affiliated Hospital of Guangzhou Medical University. According to the coin toss method, patients were randomly divided into a trial group (n=22; modified digital guide assisted implantation) and a control group (n=18; free hand implantation). The data of neck deviation, tip deviation, depth deviation, and angle deviation were compared between groups for preoperative and postoperative cone beam CT overlap analysis. One week after the operation, the patients' satisfaction with the operation was assessed by visual analog scale score. RESULTS AND CONCLUSION: (1) The trial group included 25 implants (12 in the upper jaw and 13 in the lower jaw); the control group included 23 implants (8 in the upper jaw and 15 in the lower jaw). The neck deviation, tip deviation, depth deviation, and angle deviation of the trial group were all smaller than those of the control group (P < 0.05, P < 0.001). There was no significant difference in accuracy between the maxillary and mandibular implant site in the trial group (P > 0.05). (2) There was no significant difference in satisfaction with the operation between the two groups (P > 0.05). (3) The results showed that improving the digital guide plate for assisted implantation for missing second molar can improve surgical accuracy and is suitable for patients with small opening and small interocclusal distance in the posterior tooth area. [ABSTRACT FROM AUTHOR]

Background: Calcium hydroxide [Ca(OH)2] is widely accepted as a biocompatible interappointment intracanal medicament. This study aimed to analyze the efficacy of Ca(OH)2 placement into the C-shaped canal system of mandibular second molars using the syringe method with and without lentulo spiral utilizing micro-computed tomography (micro-CT). Methods: Twenty-four extracted mandibular second molars were instrumented and classified into C-shaped floors (n = 12) and non-C-shaped floors (n = 12). Both groups were placed with Ca(OH)2 using the syringe system, then all teeth were scanned and cleaned, and placed with Ca(OH)2 again but with the syringe system followed by lentulo spiral and rescanned. The specimens were scanned using micro-CT to analyze the volume, volume percentage, uncontacted surface area, and uncontacted surface area percentage of Ca(OH)2 with the two delivery methods in the entire canal and at the apical 4 mm of the canal. Mann-Whitney test and Wilcoxon signed-rank test were used to determine the statistical differences among the groups. Results: Syringe administration used in conjunction with lentulo spiral presented lower uncontacted surface area, a lower percentage of uncontacted surface area, larger volume, and a higher percentage of volume than syringe without lentulo spiral (P < 0.05). There was no significant difference between the C-shaped floor group and the non-C-shaped floor group (P > 0.05) in the Ca(OH)2 uncontacted surface area, volume, and percentages at different regions of canals and among different delivery techniques groups. Conclusions: The lentulo spiral and syringe technique combination can increase the volume and contacted surface area of Ca(OH)2 in the C-shaped canal system of mandibular second molars. [ABSTRACT FROM AUTHOR]

Background: This study investigated the characteristics of Monson's sphere in Chinese young adult females with individual normal occlusion to provide a reference for oral rehabilitation in prosthodontic and orthodontic treatments. Methods: Points at the dental cusps and incisal edges were selected from 51 digital mandibular dental models of Chinese young adult females (aged 18–22 years) with individual normal occlusion. Monson's spheres were fitted to the selected points based on the least-squares principle and the radii were calculated. The deviation of each selected point from its relative spherical surface was also calculated. The radii and deviations of these points were examined using conventional descriptive statistics and distributions of the most deviated points inside and outside the spheres were analyzed. Results: The mean radius of Monson's sphere in Chinese young adult females was 79.60 ± 14.13 mm. The deviation of each selected point from its relative sphere surface was 0.38 ± 0.30 mm. The maximum deviations inside and outside the sphere were 0.93 ± 0.25 mm and 0.95 ± 0.30 mm, respectively. The most deviated points outside the spheres were mainly distributed at the distolingual cusps of the mandibular second permanent molars (31.37%), while those inside the spheres were mainly distributed at the mesiolingual cusps of the mandibular first permanent molars (45.10%). Conclusions: The radius of Monson's sphere in Chinese young adult females was smaller than the classic four-inch value suggested by Monson. Deviation was observed from all selected points to their Monson's sphere surface, with the most deviated points distributed primarily in the molar region. [ABSTRACT FROM AUTHOR]

Vital pulp therapy (VPT) has been increasingly advocated due to its advantages in preserving tooth vitality. While VPT is often successful, failures can occur, and traditional root canal therapy is often recommended following VPT failure. This case report provides an example of successful preservation of tooth vitality using coronal pulpotomy (CP), a more invasive type of VPT, after failure of partial pulpotomy (PP) that had been performed in a healthy 10-year-old boy. A mandibular right first molar with a diagnosis of reversible pulpitis was initially treated with PP, which included the use of tricalcium silicate cement as a pulp dressing and a resin-modified glass ionomer cement base, followed by placement of a composite resin restoration. The restoration dislodged after 34 months without complaints from the patient or radiographically detectable lesions. A stainless steel crown was placed on the tooth; however, 15 months after crown placement, the patient returned with symptoms in the treated tooth. The tooth was diagnosed with irreversible pulpitis and asymptomatic apical periodontitis but responded positively to cold testing, and the pulp appeared clinically vital upon direct inspection. The tooth was re-treated with CP, including the use of mineral trioxide aggregate as a dressing material, and examination 21 months posttreatment revealed successful resolution of the periapical lesion. When a tooth remains vital, a more invasive type of VPT may be an alternative to root canal therapy for treating failures in more conservatively treated teeth. Moreover, regular periodic recalls are essential for ensuring tooth survival and early detection of problems (ie, restoration failure) that may worsen treatment outcomes. [ABSTRACT FROM AUTHOR]

Introduction Rotary systems have made significant advances to improve their root canal preparation efficacy. These instruments can properly preserve the root canal anatomy and morphology. The present in vitro study aimed to compare canal transportation and centering ability of RaCe and Af f-one systems using cone-beam computed tomography. Materials and Methods: Thirty-six mandibular molars were included. The samples were randomly assigned to two groups (n=18): group 1, RaCe, and group 2, Af f- one. Canal preparation was conducted using the respective files according to the manufacturers' instructions. The cone-beam computed tomographic scanning of the samples was performed before and after preparation. The data were analyzed by using two-way ANOVA. Results: In both the RaCe and Af f-one rotary systems, canal centrality and transportation were similar at coronal, middle, and apical cross- sections. In addition, canal transportation and centrality were identical in the RaCe and Af f-one rotary files (P<0.05). Conclusion: The two studied rotary systems did not exhibit significant differences in root canal transportation and preservation of root canal centrality in the apical, middle, and coronal thirds. [ABSTRACT FROM AUTHOR]

Introduction: Untreated canals represent the primary cause of treatment failure in molars and the second leading cause in other dental groups. This study determined the prevalence of untreated canals and their relationship with periapical periodontitis using cone-beam computed tomography (CBCT) images. Materials and Methods: 385 CBCT images with at least one treated canal were selected from the oral and maxillofacial radiology center. The number of roots and canals, presence, and size of periapical pathology, and presence of untreated canals were recorded. The study used descriptive statistics and Chi-square, Fisher's exact, and odds ratio tests to analyze data. Results: Of the 2053 teeth examined, 14.9% had at least one untreated canal. Untreated canals in teeth increase the chance of having a periapical lesion, raising the prevalence by 11 times. Of these, 91.8% had both untreated canals and periapical lesions. This was more than teeth without untreated canals (35.8%). Most untreated canals were in maxillary molars (65.3%), and mandibular molars (12.54%). There was a statistically significant relationship (P<0.001) between the number of roots, canals, expansion, destruction, and jaw type with the prevalence of untreated canals. The maxillary first molar (68.66%) and second mesiobuccal (MB2) canal (63.27%) had the highest percentages of untreated canals. Conclusions: The MB2 had the highest prevalence of untreated canals. The presence of untreated canals significantly increased the risk of expansion and/or destruction. Therefore, identifying these conditions can also be useful in diagnosing untreated canals. Dentists should assess the anatomy of the tooth and the structure of the root canal to minimize the possibility of an untreated canal. CBCT can assist in this process. [ABSTRACT FROM AUTHOR]

Background.: This in vivo study assessed the accuracy of single-tooth monolithic zirconia crowns made using an intraoral scanner (IOS) and computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Methods.: Thirty patients requiring single posterior crowns were selected. The teeth were prepared with a deep chamfer finish line with a 1-mm extension subgingivally and a 1-mm reduction in all surfaces by one prosthodontist. The gingival margins were retracted using a gingival retraction paste before making impressions using a Trios scanner. All the digital impression files were sent to one laboratory using the dental designer software (3Shape, Copenhagen, Denmark). After completing the milling and sintering processes, the crowns were dyed and glazed. After removing the temporary crown, the qualitative assessment of proximal contacts of definitive monolithic zirconia crowns was performed according to the CDA criteria. Data were analyzed with Friedman's two-way analysis and independent t-test at α=0.05. Results.: The difference in axial and total gaps between premolar and molar teeth was not significant; however, the mean marginal gap of molars was higher than that of the premolars (P =0.043). Furthermore, the comparison of the axial, total, and marginal gaps between the upper and lower jaws showed no significant difference (P >0.05). The distribution of occlusal and proximal contacts indicated 60% and 66.7% proper contacts and no contacts in 6.7% and 10% of cases, respectively. Conclusion.: Using IOSs could result in accurate monolithic zirconia crowns in terms of adaptation. Also, most occlusal and proximal contacts did not need any adjustments. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this report was to assess the skeletal, dental and soft tissue changes in a juvenile patient with a severe class III malocclusion. This case report describes a novel method of class III treatment using skeletal anchorage for maxillary protraction and Alt-RAMEC protocol. Patient concerns: The patient did not have any subjective complaints before treatment and there was no family history of class III malocclusion. Clinical findings and primary diagnoses: Extra-orally, the patient had a concave profile with a retrusive mid-face and prominent lower lip. The intra-oral examination revealed angle class III malocclusion with a −3-mm overjet. There was no anterior displacement on closure when the patient was assessed clinically. According to the cephalometric analysis, the sagittal jaw relation and Wits appraisal were reduced due to a retrognathic maxilla and prognathic mandible. Interventions: The treatment plan involved maxillary protraction, Alt-RAMEC protocol for 10 weeks and upper molar distalisation with a hybrid hyrax distalizer in combination with a mentoplate. The active treatment time was estimated to 18 months followed by 6 months retention with the appliance. Outcomes: The sagittal jaw relationship was increased by approximately 9°, mainly due to maxillary advancement of 8 mm and a positional change of the mandible anteroposteriorly. Natural decompensation of the lower incisors was also observed. In addition, both the facial profile and the smile became more harmonious after treatment. The treatment analysis revealed that the changes achieved were mainly skeletal and it was possible to avoid adverse effects on the dentition. Conclusion: In conclusion, treatment with a hybrid hyrax distalizer combined with mentoplate using the Alt-RAMEC protocol is effective in correcting the anteroposterior discrepancy in a juvenile class III patient and it is possible to achieve maxillary advancement of 8 mm. [ABSTRACT FROM AUTHOR]

Chronic osteomyelitis resulting from foreign body entrapment in the pediatric mandible presents unique challenges in diagnosis and management. Habitual insertion of objects into the oral cavity by children can lead to serious complications such as discharging sinuses and osteomyelitis. We present a case of a 12-year-old boy with extra-oral pus discharge originating from the mandible, ultimately traced to an embedded iron nail adjacent to a carious first molar. Radiographic imaging played a crucial role in diagnosis, revealing the foreign object and. Long-term follow-up showed successful healing with prompt treatment. Prevention through parent education, meticulous examination, and interdisciplinary collaboration are emphasized to avoid such complications. [ABSTRACT FROM AUTHOR]

Background: A xanthoma is a rare bone condition consisting of a predominant collection of lipid-rich, foamy histiocytes. The central xanthoma of the jaws is a unique benign tumor. Case report: A 15-year-old Caucasian male has been presented to our department. He had radiological changes in the area of the left mandibular angle, with an area of diffuse osteolysis of 3.0 cm by 2.0 cm. Computed tomography reveals an area of diffuse osteolysis that starts from the distal root of the lower second molar and reaches the ascending process. A bone biopsy was performed, which revealed a benign proliferative process composed of histiocytic cells involving and infiltrating trabecular bone in a background of loose fibrous connective tissue devoid of any other significant inflammatory infiltrate. The size of the formation was 2.9 cm by 2.0 cm. Immunohistochemical staining for CD68 was strongly positive and negative for S-100 and CD1a. From routine blood tests, cholesterol, triglycerides, and blood sugar are within normal values, which excludes systemic metabolic disease. Subsequent to the surgical intervention, the patient underwent postoperative assessments at intervals of 14, 30, 60 days, and a year later, revealing the absence of any discernible complications during the aforementioned observation periods. Conclusion: The diagnosis of primary xanthoma of the mandible is rare and can often be confused with other histiocytic lesions. A differential diagnosis should be made with nonossifying fibroma and Langerhans cell histiocytosis, as in our case. In these cases, immunohistochemistry with CD 68, S-100, and CD1a, as well as blood parameters, are crucial for the diagnosis. [ABSTRACT FROM AUTHOR]

Dogs are animals with strong bite force. This strong bite mechanism has led to significant changes in the skeletal system such as fossa masseterica. It can be thought that one side is used more than the other side in chewing and is related to the preference of using the same side's hand, eye and foot. In the study, directional asymmetry and fluctuating asymmetry, which occurs as a result of chewing asymmetry, were examined on the first molar teeth and the fossa masseterica in 85 dog mandibles including a wide diversity of morphotypes. The association of high PC1 values for directional asymmetry with a pronounced cranial index, as evident in breeds like Pekingese, Pomeranian and Bulldog, indicates a potential evolutionary or selective breeding trend favouring brachycephaly. On the contrary, guardian breeds like the German shepherd and Bernese mountain dog, which typically require strong jaws for their roles, showcased reduced PC1 values, which might be related to their functional morphology. Similarly, the PCA results for the first molar teeth shape variations also highlighted the influence of cranial shape, with boxer dogs displaying notably higher PC1 values. The fluctuating asymmetrical distributions provided valuable insights into individualistic variations. Interestingly, no specific breed distribution trend was observed for these asymmetries, indicating a more individual‐based variation rather than breed‐based. It is essential to note that while these results provide valuable insights, further studies are required to understand the underlying causes better. Factors like genetic variations, developmental processes, dietary habits and external environmental factors could play pivotal roles in these observed morphological differences. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate in the absence of teeth the variability of the mylohyoid line (ML), the microarchitecture of the adjacent bone, and whether the variable prominence/width of the ML is associated with the quality of the adjacent bone. Methods: µCT scans of 28 human mandibles from anatomical specimens were analyzed. The following parameters were assessed in four edentulous areas (first and second premolar (PM), first, second, and third molar (M1/2/3)): ML width, cortical thickness (CtTh), average cortical- (Avg.Ct.BV/TV), and trabecular bone volume fraction (Avg.Tb.BV/TV). Results: The ML width increased from the PM towards the M2 region, which also showed the highest variance (range: 0.4–10.2 mm). The CtTh showed a decrease in the M3 region, while Avg.Ct.BV/TV and Avg.Tb.BV/TV hardly differed among the regions. In the multivariable model on the effect of the various parameters on the ML width, only gender and tooth region were significant. Specifically, male specimens were associated with a wider ML width compared to female specimens and the M2 region was associated with a wider ML width compared to the other tooth regions. Conclusion: The ML width was not associated with the cortical and trabecular bone quality in the adjacent bone, while gender and tooth region had a significant effect. Specifically, the ML width was lower in female, but peaked in the M2 region with a median width of 3–4 mm. Clinical relevance: From a clinical point of view, it was confirmed that the ML is in general a highly variable structure, especially in the M2 region, but the ML width does not allow any conclusions on the bone quality. Altogether, this underlines the need for an individual and accurate diagnostic prior to any surgical intervention. [ABSTRACT FROM AUTHOR]

BACKGROUND: For teeth with normal dental crown height, pulp cavity retention crown restoration with different depths of the pulp cavity and different repair materials affects the stress and flexural strength of tooth tissue. For short crown molar defects, the research on pulp cavity repair mainly focuses on clinical observation and in vitro flexural strength experiments. OBJECTIVE: To establish a three-dimensional finite element model for short crown molar restored by the endocrown after root canal treatment to analyze the effects of different pulp cavity retention depths and different repair materials on the distribution and size of dentin equivalent stress. METHODS: Based on establishing the complete model of the short crown mandible first molar, a three-dimensional finite element model was established for repairing the distal adjacent defect of the short crown molar with different pulp cavity retention depths (h=2, 3, 4 mm) and different repair materials (zirconia, lithium disilicate). Under the oblique loading, the equivalent stress distribution was observed. The peak value of dentin equivalent stress and the mean value of equivalent stress near the bottom of the mesial pulp cavity wall were calculated. RESULTS AND CONCLUSION: (1) Equivalent stress concentration areas: The stress of complete short crown molar and restored models mainly concentrated in the mesial root mesial neck and mesial root lingual neck. The stress concentration area was found in the mesial pulp cavity wall corresponding to the bottom layer of restored models, and the stress concentration was obvious in the 4 mm retention depth group. (2) Under the same repair material, the peak value of dentin equivalent stress was the lowest at 3 mm for all models after repair. The average value of equivalent stress near the bottom of the mesial pulp cavity wall was lowest at 3 mm. (3) Under the same retention depth, there was no significant difference between the two materials in the dentin equivalent stress peak and the mean value near the bottom of the mesial pulp cavity. (4) The results showed that under the conditions of this experiment, the endocrown was used to repair the defect of the short crown molar and the retention depth was 3 mm, which was more beneficial to protect the remaining dental tissue. The selection of zirconia or lithium disilicate as the repair material had little effect on the dentin stress. [ABSTRACT FROM AUTHOR]

In this case report, the regeneration method was used to treat the previously treated first molar, which presented with symptoms of pain during chewing and secondary acute apical periodontitis. Due to the importance of preserving the patient's permanent teeth in order to maintain optimal space and function, the regeneration treatment was performed in two visits and according to the American Association of Endodontists (AAE) guidelines. The continuation of tooth root development, healing of periapical radiolucency and positive response to sensibility test (cold test) were observed during follow-up radiographs at intervals of 6 months, 1 year & 2 year. [ABSTRACT FROM AUTHOR]

Background: This systematic review aims to analyze the spontaneous dentoalveolar changes in the mandibular arch after maxillary expansion in growing patients obtained with different expansion protocols: Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander. Methods: The study adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Eligibility criteria were established in the PICO format, involving patients who underwent slow, rapid, or leaf maxillary expansion during the mixed or early permanent dentitions. A comprehensive search of electronic databases and manual searches was conducted up to December 2023. The outcome measures included inter-mandibular first permanent molar width, inter-deciduous molar and canine width, arch perimeter, and arch length; both short- and long-term results were considered. The articles that met the inclusion criteria were included in this systematic review and were qualitatively evaluated using a methodological quality scoring system with a 13-point scale. To assess the inter-examiner agreement concerning the article selection and the qualitative assessment of the included studies, Kappa statistics were computed. Results: A total of 1184 articles were identified through electronic and manual searches. After the removal of duplicates and the initial examination of the titles and abstracts, 57 articles were considered for the full text analysis, and according to the eligibility and exclusion criteria, 22 studies were finally selected, composed of 8 randomized controlled trials (RCTs) and 14 retrospective/case-control studies. The qualitative assessment of the included studies showed the following scores: 6 papers have high research quality, 5 have moderate quality, and 11 have low quality. SME demonstrated negligible mandibular changes, with less than 1 mm variation on average (range 0.46–2.00 mm) in the selected parameters and relapses observed in the long term. RME induced more significant increases, particularly in intermolar width greater than 1 mm, which ranged between 0.93 and 3.3 mm, and good stability over the long term. Leaf Expander exhibited promising short-term lower intermolar width increases greater than 1 mm and ranged from 0.5 to 1.69 mm, but long-term stability was not thoroughly evaluated. Conclusions: SME results in negligible short- and long-term effects, while RME, especially with Haas-type appliances, exhibits significant intermolar width increases that remain stable over the years. Leaf Expander shows short-term lower intermolar width increases, requiring further investigation into long-term stability. [ABSTRACT FROM AUTHOR]

Enamel hypoplasia (EH) is a qualitative defect, and it can have a significant impact on oral health. The aim of this study was to evaluate the prevalence of enamel hypoplasia in urban area in Albania. Methodology: In total, 234 children of both sexes aged 8–12 years old were randomly selected in five schools in Tirana, Albania. They underwent an intra-oral examination. Diagnostic criteria were in accordance with a European meeting on MIH held in Athens, 2003, and the FDI. Medical history was retrieved using questionnaires, and data obtained from clinical examination were recorded. Results: The prevalence of enamel hypoplasia was 12.8%. The most commonly occurring enamel hypoplasia was the mild type (58.62%). The mandibular first molar showed the highest prevalence of enamel hypoplasia (19.5%), and the maxillary canines and premolars were the least affected (2.3%). In this study, medical story did not have a significant effect on enamel hypoplasia. Conclusions: The prevalence of enamel hypoplasia remains high at 12.8%. Interestingly, the features of enamel hypoplasia were consistent across both sexes, with no correlation found between them. The predominant occurrence of mild enamel hypoplasia underscores the importance of implementing oral hygiene strategies in schools to mitigate its progression. [ABSTRACT FROM AUTHOR]

Primary tuberculous osteomyelitis involving the mandible represents less than 2% of skeletal locations. In this paper, we report a case of mandibular tuberculosis (TB) detected after histopathological analysis of the surgically resected specimen during surgical management of a suspected case of ameloblastoma. A 14-year-old male patient presented to us with history of right-sided chin swelling. The clinical examination revealed a swelling, involving right body and parasymphysis of mandible, measuring approximately 6 cm in length and 2 cm in width, extending from right lateral incisor till the first molar. Radiological scans revealed a large multiloculated osteolytic expansive lesion measuring 52 × 20 × 18 mm. Excision of the lesion was performed and reconstruction was done with iliac bone grafting. The histopathological findings revealed a granulomatous lesion, suggestive of tuberculous osteomyelitis. The patient was successfully treated with standard multidrug therapy. One year after completion of therapy, there were no signs of recurrence. Primary mandibular TB is an extremely rare entity. Its clinical presentation is not specific. Radiologically, TB has no characteristic appearance. The positive diagnosis is based on histology. Primary mandibular TB is rare and should be kept among differential diagnoses in susceptible population and in endemic areas. [ABSTRACT FROM AUTHOR]

Background: The preparation of the middle mesial (MM) canal of mandibular molars represents a challenge because it is often curved, narrow, and close to the root concave. The purpose of this study was to evaluate the ex vivo shaping ability of 3 nickel-titanium (NiTi) rotary systems in the MM canal using 3D printed resin tooth replicas. Methods: A permanent mandibular first molar with a MM canal was acquired from a pool of extracted teeth and reproduced by a 3D printer. The resin tooth replicas (n = 18) were equally assigned to 3 groups for the evaluation of the shaping abilities of 3 NiTi rotary systems (OneShape [OS], Twisted Files [TF], and ProTaper Gold [PTG]) according to the manufacturer's recommendations. The tooth replicas were scanned by micro-computed tomography (micro-CT) twice before and after instrumentation of the mesiobuccal (MB), mesiolingual (ML), and MM root canals. After 3D reconstruction, the canal straightening, change of root canal volume and surface area, the mesial and distal canal wall thickness and canal transportation at the levels of 1, 2, and 3 mm below furcation were assessed. One-way variance analysis and Turkey's post hoc test were used for comparisons of the means among different groups, and paired-t test was used to compare the mesial and distal sides of the mesial roots. Results: As compared with OS and TF, the use of PTG in preparation of MM canals resulted in significantly more straightening of canal curvature (p < 0.05), greater post-instrumentation canal volume and surface area, and thinner mesial and distal remaining canal wall thickness at 1, 2 and 3 mm below furcation (all p < 0.05). Regarding the root canal transportation in the mesiodistal direction, there was no significant difference among the 3 instruments (all p > 0.05) after the preparation of the MB and ML canals. However, in the MM canal, more pronounced transportation was detected in the PTG group at 2 mm below furcation, and in the TF group at 3 mm below furcation as compared with the other 2 systems (both p < 0.05). Conclusions: 3D printed tooth replicas have the advantages of consistency and can be an ideal model to evaluate the shaping ability of different instruments in the MM canal. OS and TF files performed similarly and both are appropriate for shaping the MM canal, while PTG may cause excessive and uneven resin removal, especially near the furcation, and may lead to root fragility and procedural errors. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the trueness and precision of four intraoral scanners (IOSs) and splinted open-tray conventional implant impression (SOCI) in partial and total edentulism. Materials and Methods: Four gypsum models (Model A—implants at mandibular right second molar, right second premolar, and right canine; Model B— implants at mandibular right canine, left central incisor, and left canine; Model C—implants at mandibular right second molar, right second premolar, right canine, left central incisor, and left canine; and Model D—implants at mandibular right second molar, right second premolar, right canine, left central incisor, left canine, left second premolar, and left second molar) were prepared, and four different IOSs (Aadva IOS, CS 3600, Trios 3, and Emerald) and one polyvinyl siloxane (PVS) were used. Reference models were digitized with a high-resolution industrial scanner, and data were superimposed. Root mean square (RMS) values were calculated by software and defined as deviation values after superimposition. The oneway analysis of variance (ANOVA) test and Tukey honest significant difference (HSD) test were performed to analyze the data (P < .05). Results: For Models A and B, the truest impressions were made with Aadva, followed by CS 3600, PVS, Trios 3, and Emerald, respectively, while for Model C, the truest impressions were made with CS 3600, followed by Aadva, PVS, Trios 3, and Emerald, and for Model D, the truest impressions were made with Aadva, followed by CS 3600, PVS, Emerald, and Trios 3 (P < .05). There was no statistical difference between groups for precision in Models A, B, and C (P > .05); however, PVS showed lower precision values than other groups in Model D (P < .05). Conclusion: In partial edentulism, IOSs are true and precise as SOCI except Emerald. However, the trueness of IOSs is not favorable in total edentulism cases. SOCI with PVS in total edentulism treated with implants is less precise than IOSs. [ABSTRACT FROM AUTHOR]

Objective: To analyse the anterior teeth effects of clear aligners on five different patterns of mandibular molar movement and to define the most effective configuration to be implemented with clear aligners through finite element analysis. Methods: A three-dimensional mandibular model with a deep overbite in the mandible was constructed using cone beam computerized tomography (CBCT) data. The model included the mandibular dentition, mandibular periodontal ligaments, attachments, and aligners. Five models were created: (1) configuration A: second molar distalization (0.25 mm); (2) configuration B: second molar distalization (0.25 mm), first molar extrusion (0.15 mm); (3) configuration C: second molar distalization (0.25 mmm), first and second premolar extrusion(0.15 mm); (4) configuration D: second molar distalization (0.25 mm), first molar and first/second premolar extrusion(0.15 mm); and (5) configuration E: second molar distalization (0.25 mm), first molar and first/second premolar extrusion (0.15 mm), first molar and first/second premolar expansion (0.15 mm). Results: In all configurations, the anterior teeth exhibited labial tipping and the mandibular central incisor of configuration E showed the highest labial tipping. Configuration E demonstrated a relatively minor impact on mandibular molars distalization compared with configuration A. Configuration A showed the highest distal displacement value, and configuration E produced the lowest displacement value. Configuration E caused the highest periodontal ligament (PDL) pressure of the central and lateral incisors. The differences in the canines between configurations C and D,were not significant, and the stress distribution differed among the five groups. Conclusions: All patterns utilizing clear aligners facilitated mandibular molar distalization. Extruding the premolars and second molar distalization at the same time had little impact on second molar distalization; When expansion and extrusion were simultaneously performed during the distalization of mandibular molars, our prime consideration was the alveolar bone on the labial side of the anterior teeth to prevent the occurrence of gingival recession, dehiscence, and fenestration. Due to the lack of consideration for periodontal tissues in this study, clinical protocols should be designed based on the periodontal status of the mandibular anterior teeth. [ABSTRACT FROM AUTHOR]

Background: This study aimed to compare the apical transportation and centering ability of One Curve, HyFlex EDM, and EdgeFile X1 in curved mesiobuccal and mesiolingual canals of mandibular first molars. Materials and Methods: In this in vitro experimental study, 60 mesiobuccal and mesiolingual canals of the mandibular first molars with a minimum length of 19 mm and 25°-40° curvature were randomly divided into three groups (n = 20) for root canal preparation with One Curve, HyFlex EDM, and EdgeFile X1. After access cavity preparation and confirming the glide path, the baseline micro-computed tomography (micro-CT) scans were obtained, and the root canals were instrumented with the respective systems according to the manufacturers' instructions. Apical transportation and centering ability were assessed at 1, 3, 5, and 7 mm from the apex by comparing pre- and postinstrumentation micro-CT scans. One-way ANOVA, independent t-test, and Duncan's post hoc test were used to statistically compare the groups, and data were analyzed by SPSS version 24 (alpha = 0.05). Results: The three groups were not significantly different regarding apical transportation at 5 and 7 mm from the apex (P > 0.05). At 1 mm level, One Curve caused significantly lower apical transportation; while, at 3 mm level, HyFlex EDM resulted in significantly higher apical transportation (P < 0.05). No significant difference was noted in the centering ability of the three groups at 1, 3, and 5 mm from the apex (P > 0.05). At 7 mm level, EdgeFile X1 showed significantly lower centering ability (P < 0.05). Conclusion: One Curve caused lower canal transportation in the apical third compared with EdgeFile and HyFlex EDM, but no significant difference was noted among the three in the coronal third of the roots. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study is to investigate the type of ridge (degree of angulation of the lingual concavity) and the buccolingual dimensions in the area of the first and second molars in both genders of different ages and how this will affect implant placement in the posterior mandible. Materials and Methods: This retrospective cross‐sectional study comprised cone beam computed tomography images of 150 dental patients (75 males and 71 aged ≥30). The following were measured/reported: type (morphology) of the ridge (convex [C], parallel [P], or undercut [U]), buccolingual width at the base and the crest of the ridge, and ridge height. The concavity angle, depth, and length of the U‐shaped ridge were measured too. Results: The prevalence of type U ridge ranged from 32.7% in the first molar region to 62.7% in the second molar region. Almost all measurements and ridge type distributions were comparable amongst the age groups (p >.05). Very few significant differences were found when comparing #36 versus #37 and #46 versus #47 teeth, with no differences in the distribution of the ridge types (p >.05). Quite the inverse, all measurements were statistically different when comparing #36 versus #37 and #46 versus #47 teeth, and type U ridge was more frequent in second molar compared to the first molar regions, respectively (p <.05). Many measurements were statistically higher in females; the inverse was true for a few measurements (p <.05). Type U ridge in #36 and #37 was found more frequently among males (p <.001). In contrast, the ridge types in #37 and #47 were not statistically different gender‐wise. Conclusions: The U type of ridge was more prevalent in the investigated population, encountered more frequently in the second molars generally and in the first molars of males than females. Most posterior mandibular measurements are similar age‐ and side‐wise but seem different gender‐ and tooth‐wise. [ABSTRACT FROM AUTHOR]

BACKGROUND: Lingual movable wing is a new type of lingual orthodontic technique and the different stretching lengths of the wring affect the torque control effect of anterior teeth. However, there is yet no related biomechanical research. OBJECTIVE: To investigate the displacement trend of dentition during adduction of mandibular anterior teeth and the effect of different wing stretching lengths on the biomechanical effect of mandibular anterior teeth. METHODS: The data of the mandible and lower dentition were collected by cone-beam CT and reconstructed using Mimics software to establish a three-dimensional finite element model of mandibular anterior teeth adducted by the lingual movable wing. The ANSYS software was used to analyze the initial displacement of the mandibular anterior teeth under the following conditions: A, 2 mm stretching length; B, 2.5 mm stretching length; C, 3 mm stretching length; and D, 3.5 mm stretching length. RESULTS AND CONCLUSION: The trend of initial displacement of lower dentition: The central incisors moved lingually with depression, the lateral incisors and canines moved mildly lingually with mesial lingual torsion, the second premolar was tilted distally with a marked lingual inclination and the first molar showed an overall mesial inclination with mesial crown eversion. Therefore, in the adduction cases of mandibular tooth extraction, attention should be paid to the lingual movement of the second premolar, which could be offset by corresponding techniques in clinic. The trend of anterior tooth displacement in all directions: from condition A to condition D, in the sagittal direction, the difference value in crown-root displacement of central incisors changed from -11.891 μm to -5.757 4 μm, indicating that the central incisor changes from oblique movement to overall movement. The difference value in crown-root displacement of lateral incisors changed from -11.828 1 μm to -6.711 45 μm, and that of canines changed from -7.572 3 μm to -4.695 5 μm, indicating that the oblique movement of the lateral incisors and canines is also changing to an overall movement. In the vertical direction, from condition A to condition D, the reduction of incisors was gradually increased, while that of canines was gradually decreased. These findings indicate that the stretching length of the wing can affect the oblique movement trend of the anterior teeth. As the wing continues to stretch, the torque control of the lower anterior teeth will become better. [ABSTRACT FROM AUTHOR]

Background: Genetic and epigenetic alterations have significant impacts on the morphology of permanent mandibular premolars and molars. Geometric morphometry is a powerful technique, which can be utilized to identify specific landmarks that exhibit variation and that are associated with ancestry and dimorphism. Methods: The geometric and anatomic landmarks of mandibular premolars and molars were extracted from 3D digital replicas of diagnostic dental casts prepared for model analysis (n = 160). Tooth shape analysis was conducted using various techniques, including Procrustes superimposition, Procrustes ANOVA, discriminant function analysis, and the regression of shape over the centroid size. Results: Procrustes ANOVA showed that centroid size was not significantly different between the two sexes, but shape was significantly different in the two-cusp-type second premolars (p = 0.0035) and in the first/second molars (p < 0.001). The three-cusp type of the second premolars showed the highest degree of allometry, with 3.35%, followed by the mandibular second molars, with 3%, indicating that distal class types have a tendency to exhibit allometry. The distal and lingual components of the tooth showed more variability, and females tended to have sharper cusp configurations. Conclusions: This study shows how landmarks vary in permanent human post-canine dentition, a crucial finding for anatomic reconstruction and restorative dentistry. In particular, the molars and premolars of the mandible post-canine teeth are critical for achieving optimal masticatory efficiency and overall health. Additionally, a higher degree of allometry and the later formation of cusps correlate with greater shape variation, particularly on the distal and lingual sides. For precise restorative procedures, a thorough understanding of the anatomy of these teeth is required. [ABSTRACT FROM AUTHOR]

Background: This study intended to evaluate the association between several endodontic prognostic factors with the presence of periapical lesions (PLs), their volume, and bone characteristics including cortical bone destruction (CBD) and buccal plate bone height (BPBH) in root-filled molar teeth using cone-beam computed tomography. Methods: A collection of 143 scans of endodontically treated maxillary/mandibular first or second molars recorded over 8 years, were obtained from a specialized radiology center. Data on prognostic factors including tooth number, gender, jaw type, the status and number of missed canals, obturation length, restoration type, presence of a separated instrument, presence of a post or screw in the canals, and presence of perforation were collected. The assessed outcomes included PL presence, PL volume, CBD, and BPBH. The association between prognostic factors and outcomes was evaluated using multiple logistic regression models with adjusted covariates and multifactorial ANOVA at a significance level of 0.05. Results: A total of 282 molars from 82 women and 50 men with a mean age of 40.6 ± 12.27 were included. Among those, 139 teeth presented PL with a mean volume of 18.68 mm3. CBD was prevalent in 137 teeth and the mean BPBH appeared to be 9.45 mm. The presence of a missed canal (OR = 10.022, P <.05), underfilled canal (OR = 3.725, P <.05), overfilled canal (OR = 15.859, P =.018), and perforation (OR = 15.261, P =.013) was significantly associated with PLs. None of the prognostic factors could considerably contribute to the CBD (P >.05). The presence of a missed canal was positively associated with the PL volume (P <.05). Similarly, missed canals (P <.05), perforation (P <.05), and separated instruments (P =.004) were associated with a significantly reduced BPBH. Conclusions: Overfillings, perforations, missed canals, and underfillings were identified as remarkable predictors of PL, arranged in descending order of their respective impact. The only factor capable of significantly increasing the PL volume was the missed canal. In brief, obturation length errors, perforations, missed canals, and separated instruments were robustly correlated with endodontic failure, which highlights the importance of mitigating the potential for errors by following the fundamentals of endodontics. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine whether or not the breed and sex factors have an effect on the shape in the mandibles of Hamdani and Awassi sheep. A total of 31 mandibles were used. The samples were analyzed via geometric morphometric methods by using semilandmark. In the study, it was determined that the first principal component accounted for 36.52% of the total shape difference. According to principal component analysis, samples were clustered significantly in terms of breed; whereas, they were not clustered in terms of sex. In terms of the first principal component, the places where the shape differences were concentrated were the attachment sites of teeth to the mandible, between the second molar and ramus mandibulae, the processus coronoideus and the angulus mandibulae. The Mandibulae of Hamdani sheep had a higher body than the mandible of Awassi sheep. The mandibulae of male sheep was more voluminous than the mandible of female sheep, especially in the body area. Consequently, it is thought that the data obtained as a result of the study would serve as a reference for the ruminant mandible remains obtained from archaeological excavations. [ABSTRACT FROM AUTHOR]

Ewing's sarcoma of bone is a rare malignant round cell tumor of the head and neck. The jaw, particularly the mandible, accounts for 3% of occurrences in the head and neck area. These tumors have been reported more frequently in men than in women, and they are usually between 5- and 20-year-old. It is difficult for clinicians and pathologists to make a diagnosis based solely on clinical and microscopic findings. Immunohistochemistry presents a plausible tool that can help the pathologist to arrive at a confirmatory diagnosis. This jaw tumor has the best prognosis when detected and treated early in the disease course, so the importance of timely, and accurate diagnosis cannot be overemphasized. The highlighting feature of this case report of an 18-year-old male that was primary detected by immunohistochemically as Ewing's sarcoma and is localized to the impacted left mandibular molars. [ABSTRACT FROM AUTHOR]

Background: This study aimed to analyse the 3D patterns of the mandibular and mental canals (MDC and MC) referring to the surrounding prominent surgical landmarks such as teeth and mental foramen by cone beam computed tomography (CBCT). Methods: CBCT scans of 354 patients aged 18–67 years with mandibular first premolar to second molar were included and reconstructed 3‐dimensionally (3D) by mimics. The parameters of MDC and MC were measured referring to teeth and mental foramen. Results: From the first premolars to the second molars, the mandibular canals showed a trend of gradually closer to the cementoenamel junction (CEJ) of the adjacent teeth and farther away from the buccal cortical plate. The distance of the MDC with the root apexes (RA) was relatively constant from the first premolar to the first molar, but became much closer to the second molar. About 10.8% of the second molars had MDC‐RA distances of shorter than 2 mm, and 1.34% even had the MDC superior to the RA. Moreover, the Type III of MC presented in 66.0% of the subjects and had a relatively longer length. Besides, the existence of Type I MC may be related to the MDC featuring with close distances to the RA and CEJ of the adjacent teeth. Conclusion: Dentists and surgeons should know the patterns of mandibular and mental canals. A better understanding of the MDC and MC and their relationship to local anatomical landmarks may facilitate the planning of surgeries and alert potential nerve injuries in the operative procedures. [ABSTRACT FROM AUTHOR]

Statement of the Problem: Bond strength of furcation repair materials is an essential factor in clinical success. Studies on the effect of adding titanium dioxide (TiO2) nanoparticles on the push-out bond strength of commonly used endodontic cements for furcation perforation repair is limited. Purpose: This study aimed to evaluate the effect of adding TiO2 nanoparticles to white Portland cement (PC), white mineral trioxide aggregate (MTA), and calcium enriched mixture cement (CEM) on their push-out bond strengths. Materials and Method: In this in vitro study, 120 endodontically treated molars were assigned to six groups (n=20) based on the material used to repair the perforation. In three groups, the cements (white PC, white MTA, and CEM) were placed in pure form, and in the three remaining groups, 1 weight % of TiO2 was added. The push-out bond strength was measured using a universal testing machine at a strain rate of 0.5 mm/min. Data were analyzed using one-way ANOVA and post hoc Games-Howell test (p< 0.05). Results: One-way ANOVA showed significant differences in the mean bond strength values between the six groups (p= 0.002). The post hoc Games-Howell test showed that the bond strengths in MTA+TiO2 and PC+TiO2 groups were significantly higher than those in MTA and PC groups, respectively. However, there was no significant difference in the bond strength between CEM and CEM+ TiO2 groups. Conclusion: The incorporation of TiO2 into MTA and PC increased their push-out bond strength. However, it did not affect the push-out bond strength of CEM cement. [ABSTRACT FROM AUTHOR]

The usage of monolithic zirconia has been increasing in daily practice in dentistry for the last 20 years. Monolithic zirconia is mainly used for posterior sector rehabilitation, as it lacks optical properties and has good technical properties; it does not chip and reduces antagonist wear compared to metal–ceramic prostheses. However, monolithic zirconia may present some issues, mainly low-temperature degradation (LTD), also known as "aging", which must be considered and investigated in clinical studies with prolonged follow-up periods. The aim of this study was the aesthetic and functional evaluation of single monolithic zirconia crowns that were screwed onto implants for posterior dental rehabilitation using USPHS parameters and a long follow-up period of 7 years. The results showed that the USPHS scoring reduces year by year, passing from 100% excellence between the first and fourth years of observation, to 88% excellence and 12% success in the seventh year. Screw abutment loosening was the only technical adversity reported; no implant failure, crown fracture, or irreparable damage were additionally registered. Considering the emerging results and comparing them with the data available in the literature, the authors suggest that monolithic zirconia crowns could be considered as a valid alternative to classic metal–ceramic rehabilitations for the rehabilitation of posterior sectors. [ABSTRACT FROM AUTHOR]

Aim: The aim of the study was to compare the stresses caused of different crown heights on short implants with different lengths, diameters, and designs under axial and oblique loads on the cortical bone and implant system using finite element analysis. Methodology: In the atrophic posterior mandible, four different implants of different sizes and designs were placed in the first molar region. Metal supported porcelain crowns with three different heights (10 mm, 12.5 mm, and 15 mm) were designed on the computer. A total of 12 study models were created. Axial and oblique loads were applied, and Von Mises values in the implant and abutment; maximum and minimum principal stress values in the cortical bone were evaluated by the finite element analysis method. Results: Compared to axial load, significantly higher stress values were found at the implant and cortical bone in obliquely loaded models. As the length and diameter of the implant increased, the stress on the cortical bone decreased. Compared to the threaded implant, the plateau design implant caused less stress on the bone under vertical loads, while causing more stress on the oblique. Unlike the literature, it was observed that the stresses on the implant were higher in the larger diameter implant compared to the narrower. Conclusion: As a result of the stress values obtained within the limits of the analysis, when the lengths of the crowns restored on short implants were compared, it was determined that the axial forces were at an acceptable level under all conditions. [ABSTRACT FROM AUTHOR]

Objectives: This study was designed as a prospective randomized single-blind clinical trial to compare the anesthetic efficacy of inferior alveolar nerve block (IANB), IANB plus buccal infiltration, and IANB plus lingual infiltration of 4% articaine with 1:100,000 epinephrine in mandibular molars with irreversible pulpitis. Method and materials: Sixty healthy volunteers who had a first or second mandibular molar diagnosed with irreversible pulpitis participated in the present study. This study was composed of three arms for the first molar and three arms for the second molar. Subjects in test arm A received two IANB injections (3.6 mL). Subjects in test arm B received 1.8 mL IANB injection plus 1.8 mL buccal infiltration. Subjects in test arm C received 1.8 mL IANB injection plus 1.8 mL lingual infiltration. Articaine (4%) with 1:100,000 epinephrine was used for all injections. The subject's pain during access preparation and pulp extirpation was recorded on the Heft-Parker visual analog scale. Success was defined as "none" or "mild" pain during treatment. Kruskal-Wallis test was used to compare pain categories in three groups of interventions for each mandibular molar. Results: IANB with a supplemented buccal infiltration provided more success than IANB alone or IANB plus lingual infiltration, in first molars (P = .019). There were no significant differences between the three injection techniques in second molars (P = .795). Conclusions: Adding a supplemental buccal infiltration to a standard IANB was more successful in providing pain-free treatment for patients experiencing irreversible pulpitis in mandibular first molars. [ABSTRACT FROM AUTHOR]

Supernumerary teeth can have normal or abnormal morphologic structure and characteristics, and their impacted form is diagnosed usually during X-ray examinations. In this case report, the presented patient is a 16-year-old female with anterior and right posterior open bite and bilateral posterior crossbite, upper right supernumerary paramolar, and impacted second and third molars. The paramolar development was the reason for the asymmetric growth of the alveolar bone in the upper jaw. The development of the bone is connected with the development of the teeth, and one additional tooth leads to extensive development in the maxilla. There is a risk of gingival recession occurrence when leveling the lower incisors due to the thin gingival biotype. A combined surgical-orthodontic treatment was done according to the following plan: extraction of supernumerary paramolar, germectomy of the upper right third molar (18) and at the same time periodontal graft in the lower anterior segment. A digitally three-dimensional (3D) printed appliance for rapid maxillary expansion was used for the transverse insufficiency of the upper jaw. The upper dental arch expander was designed with distal extension in the area of the upper right second molar (17). The extension was used as an anchorage during the orthodontic traction of the second molar. The treatment continued with a fixed orthodontic appliance—braces in the upper and lower jaw. With the extraction of the impacted and supernumerary teeth in the right maxillary segment, the eruption of 17 was stimulated and a change in the height of the alveolar bone was achieved. This favored the vertical changes and normalization of the occlusion. The maxillary expansion was also a significant factor in normalizing the occlusion. Observations on paramolar behavior showed that more often they develop in the bone and do not erupt. Each clinical case is highly individual, and patients seek orthodontic treatment at different stages of dentition development and corresponding development of the supernumerary teeth. [ABSTRACT FROM AUTHOR]

Background: Knowledge about the anatomy and morphology of the root canal system is essential for successful surgical and non-surgical root canal treatments. However, precise assessment of the root morphology and anatomy is not often possible on two-dimensional radiographs. This study aimed to investigate the association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography (CBCT). Methods: This cross-sectional study evaluated 1,231 CBCT scans of mandibular second molars obtained between October 2018 and February 2022 that were retrieved from the archives of a private radiology clinic. Panoramic-like images were reconstructed from the CBCT scans. The root morphology of mandibular second molars was classified on panoramic-like images as type 1, 2, 3, 4, or 5. The root pattern on axial CBCT images was classified into three types of single, double and C-shaped. The association of root morphology on panoramic-like and axial CBCT views was analyzed by the Chi-square test and Fisher's exact test at 0.05 level of significance. Results: Of all, 62.7% of mandibular second molars were type 1; out of which, 97.3% had a double-root pattern on axial CBCT images. Also, 28.6% of them were type 2; of which, 92.6% had a double-root pattern. Moreover, 3.9% were type 3; of which, 47.9% had a C-shaped pattern; 0.9% were type 4, and 45.5% of them showed a single-root pattern; 3.8% were type 5 with 76.6% of them showing a single-root pattern. The prevalence of C-shaped canals was higher in females, and most C-shaped canals had a C3 pattern. Conclusion: Root morphology on panoramic-like CBCT views had a strong association with the root canal pattern on axial CBCT views. According to the results, mandibular second molars with a type 3 morphology on panoramic-like CBCT images are highly probable to have a C-shaped canal. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the functional load capacity of the periodontal ligament (PDL) in a full arch maxilla and mandible model using a numerical simulation. The goal was to determine the functional load pattern in multi- and single-rooted teeth with full and reduced periodontal support. CBCT data were used to create 3D models of a maxilla and mandible. The DICOM dataset was used to create a CAD model. For a precise description of the surfaces of each structure (enamel, dentin, cementum, pulp, PDL, gingiva, bone), each tooth was segmented separately, and the biomechanical characteristics were considered. Finite Element Analysis (FEA) software computed the biomechanical behavior of the stepwise increased force of 700 N in the cranial and 350 N in the ventral direction of the muscle approach of the masseter muscle. The periodontal attachment (cementum–PDL–bone contact) was subsequently reduced in 1 mm increments, and the simulation was repeated. Quantitative (pressure, tension, and deformation) and qualitative (color-coded images) data were recorded and descriptively analyzed. The teeth with the highest load capacities were the upper and lower molars (0.4–0.6 MPa), followed by the premolars (0.4–0.5 MPa) and canines (0.3–0.4 MPa) when vertically loaded. Qualitative data showed that the areas with the highest stress in the PDL were single-rooted teeth in the cervical and apical area and molars in the cervical and apical area in addition to the furcation roof. In both single- and multi-rooted teeth, the gradual reduction in bone levels caused an increase in the load on the remaining PDL. Cervical and apical areas, as well as the furcation roof, are the zones with the highest functional stress. The greater the bone loss, the higher the mechanical load on the residual periodontal supporting structures. [ABSTRACT FROM AUTHOR]

Background: This study aimed to compare the shaping ability of different instruments, TruNatomy Glider (TRN-G), WaveOne Gold Glider (WOG-G), and ProGlider (Pro-G) using micro-computed tomography (micro-CT). Methods: The mesial canals of 27 mandibular molars with two separate mesial canals and moderate curvature were included in this study [n = 27 mesiobuccal (MB) and mesiolingual (ML) root canal]. According to the manufacturer's instructions, the glide path was created with TRN-G, WOG-G, and Pro-G glide path instruments (n = 9 MB and ML root canal in each group). Micro-CT scanning was performed before and after preparation. Mesiodistal (MD) and buccolingual (BL) transportation and the centering ratio were measured at three levels within the canal (3, 5 and 7 mm). A three-way robust ANOVA was used to compare the parameters. Results: TRN-G showed significantly greater transportation in the MD direction than the other instruments throughout the root canal (overall root canal) (p < 0.05). The best centering ability in the BL direction was shown by the WOG-G, regardless of level within the canal and canal distinction (MB vs. ML) (p < 0.05). There was no significant difference between groups according to the level within the canal and canal parameters (p > 0.05). Whether the root canal was MB or ML did not affect centering or transportation (p > 0.05). Conclusions: Glide path instruments can be used to shape moderately curved canals with minimal apical transportation and better centering ability. All three tested glide path files can used safely before the shaping file. [ABSTRACT FROM AUTHOR]

Aim: The purpose of this study was to evaluate the effect of the density and the thickness of the cortical and the cancellous bone at selected inter-radicular areas in subjects with different facial growth patterns using cone beam computed tomography (CBCT) in order to choose the optimal area for miniscrew insertion. Materials and methods: From 150 CBCT scans, 45 scans were included in the study. The subjects were categorized into three groups based on their skeletal growth pattern according to SN-GoMe angle and facial height index. Cortical and cancellous bone density and thickness were measured at the selected inter-radicular areas. Results: Compared to the other two groups, the hyperdivergent group had thinner cortical bone in the anterior region of the maxilla between the central and the lateral incisors on the buccal side at 4 mm from the alveolar crest (P-value: 0.012) and on the palatal side at 7 mm from the alveolar crest (P-value: 0.030). Cancellous bone density values in these areas were higher in subjects with hypodivergent and hyperdivergent growth pattern. Furthermore, in hyperdivergent group less dense cortical bone in the posterior region of the maxilla on the palatal side between the second premolar and the first molar (p-value: 0.020) and on the buccal side between the first molar and the second molar (p-value: 0.038 & 0.047) was observed. No significant differences were found in the mandible between the three groups. No significant differences were found between the male and the female subjects. Conclusion: Hyperdivegents presented thinner cortical bone in the anterior of the maxilla between the central and the lateral incisors. Less dense cortical bone was found between maxillary second premolar and first molar on the palatal side and also between the maxillary first molar and the second molar on the buccal side in this group too. Normal showed higher density values in the posterior of the maxilla compared to the other two groups. No significant differences were found among three groups in mandible. [ABSTRACT FROM AUTHOR]

Background: The mental foramen is a significant anatomical landmark that plays a crucial role in performing various types of surgical procedures and administering local anesthetics for oral and maxillofacial surgeries. Having a thorough understanding of the anatomy of this area is essential for performing effective nerve blocks and avoiding any damage to the neurovascular bundles. Hence, we aim to study the anatomical location, size, and shape of the mental foramen of the mandible in the population of Bihar and compare it with the findings of other studies. The mental foramen is a significant anatomical landmark that plays a crucial role in performing various types of surgical procedures and administering local anesthetics for oral and maxillofacial surgeries. Having a thorough understanding of the anatomy of this area is essential for performing effective nerve blocks and avoiding any damage to the neurovascular bundles. Hence, we aim to study the anatomical location, size, and shape of the mental foramen of the mandible in the population of Bihar and compare it with the findings of other studies. Materials and Methods: The 120 dried fully ossified dentulous adult human mandibles (240 sides), of unknown gender and age, were used in the current cross -sectional investigation. Only those well-preserved mandibles that belonged to adults, were complete in all respects, and allowed for precise morphological observations were included in the study. Results: Our study found that the mental foramen is most commonly round (60.42%) and exits in the postero-superior direction on both sides with a frequency of 92.92%. The mean transverse diameter is 3.22 mm on the right side and 3.74 mm on the left side, with a statistically significant difference (p-value ≤0.05). The mean vertical diameter is 3.37 mm on the right side and 3.48 mm on the left side. Our findings show that the most common position of the mental foramen in relation to the lower teeth is below the apex of the second premolar, accounting for 37.08% on the right side and 36.67% on the left side. The second most frequent position is between the first and second premolar, representing 7.92% on the right side and 7.08% on the left side. Additionally, a position between the second premolar and first molar teeth was observed, accounting for 5% on the right side and 6.25% on the left side. On the right side, the distance between the mental foramen and the symphysis menti was found to be 28.71±1.36 mm, while on the left side, it was 28.94±1.19 mm. Similarly, the distance between the mental foramen and the posterior border of the ramus was 73.83±1.12 mm on the right side and 78.91±1.86 mm on the left side. The distance between the mental foramen and the alveolar crest was 17.87±1.73 mm on the right side and 18.69±1.63 mm on the left side. Finally, the distance between the mental foramen and the inferior border of the body of the mandible was found to be 16.91±1.23 mm on both sides. Conclusion: This study provides data on the location and morphometry of the mental foramen, aiding dental surgeons in avoiding nerve damage during surgeries in this region. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to clarify the effect of occlusal force on appropriate optical interocclusal registration in clinical practice, considering periodontal ligament and jawbone deformation. Methods: Forty participants with natural, healthy dentition were enrolled (19 men and 21 women; mean age, 27.7 ± 2.0 years). A TRIOS3 intraoral scanner was used to scan the right lateral first premolar to the second molar areas of the upper and lower jaws. During scanning for interocclusal registration, participants were instructed to "bite normally," "bite lightly," and "bite strongly" to obtain data for the three occlusal patterns. The standard triangulated language (STL) data for each occlusion condition were superimposed using the appropriate software, following which the tooth displacement was calculated. The conventional method was also used to record the occlusal contact area for a silicone model using a dental contact analyzer. Results: Tooth displacement was significantly lower for the strong-bite condition than for the weak-bite condition (0.018 mm vs. 0.028 mm, P<0.05). As the occlusal force increased, the occlusal contact area also increased, and significant differences were observed among the different occlusal conditions (P<0.05). Conclusions: Occlusal contact area changed depending on the bite force when using the silicone impression or optical intraoral scanning methods. Moreover, using optical impression methods in "strong bite force" may reduce the deviation and allow for stable interocclusal registration. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to compare the accuracy and agreement between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) in the assessment of canal transportation and centering ratio following root canal instrumentation with rotary files. Material and Methods: Twenty mesiobuccal canals of mandibular molars were prepared using the 2Shape sequential rotary system. CBCT and micro-CT scans were performed before and after instrumentation, and the magnitude of transportation and centering ratio were measured. The acceptable transportation was set at ≤0.15 mm. The accuracy and agreement between CBCT and micro-CT were calculated, and the intra-class correlation coefficient (ICC) and kappa coefficient were determined to assess the agreement between the two modalities. Statistical analyses were performed using repeated measures ANOVA. Results: Transportation was detected by both modalities at all distances from the apex after instrumentation. The agreement between CBCT and micro-CT in assessing canal transportation was observed in 80%, 85%, 75%, and 75% of specimens at 1-, 3-, 5-, and 7-mm from the apex, respectively. The ICC for transportation and centering ratio was much lower than 0.75, indicating poor agreement between the modalities. The kappa coefficient did not show acceptable agreement between the methods. Conclusions: CBCT and micro-CT demonstrated poor agreement in assessing canal transportation and centering ratio. Micro-CT remains the preferred modality for in vitro investigations, while CBCT should be limited to clinical settings. [ABSTRACT FROM AUTHOR]