Management of Apical Third Root Fractures in Radiculomegaly of Mandibular Anterior Teeth: A Rare Case Report.

In this case report, two uncommon fractures of the root located at the apex of the mandibular anterior teeth region were successfully treated and preserved using non-surgical endodontic procedures. These teeth possess a unique size, characterized by the presence of exceptionally elongated lateral incisors measuring approximately 29 mm, central incisors measuring approximately 25 mm, and canines measuring approximately 30 mm. For the lower left central incisor, the root canal was carefully navigated to the coronal fragment, whereas the apical fragment was left undisturbed and preserved. In the case of the remarkably elongated lower right lateral incisor, the process of 'unification' between the apical and coronal fragments was accomplished through the utilization of Gutta-percha and Ah plus sealer. Subsequently, the mandibular anterior teeth were stabilized and immobilized using dental splints for a duration of one and a half months, with regular follow-ups conducted over a span of six months and one year, during which positive healing outcomes were observed.

Microsurgical management of radicular cyst using guided tissue regeneration technique: A case report.

BACKGROUND: Radicular cyst is a lesion of odontogenic origin that arises from epithelial remains due to periapical periodontitis caused by inflammatory reactions generated at the apex of affected teeth with infected or necrotic pulps. The therapeutic management of radicular cysts is controversial. There is only one case report of enucleation of a radicular cyst managed with microsurgery and apicoectomy, but without the use of the guided tissue regeneration (GTR) technique in the same surgical procedure. The present clinical case describes the management of a radicular cyst with microsurgical approach, performance of an apicoectomy of the tooth associated with the entity, application of GTR technique, use of a resorbable membrane of type I bovine collagen, and bovine xenograft. CASE SUMMARY: A 68-year-old patient presented with a radicular cyst from an upper lateral incisor. The microsurgical management used was aimed at enucleating the chemical membrane, performing apicoectomy of the tooth along with careful and precise retrograde filling, and implementing GTR technique using a resorbable collagen membrane and bovine xenograft. The diagnosis of radicular cyst was confirmed using histopathological analysis. The patient underwent follow-up evaluations at 10 and 30 d postoperatively. At 4 months postoperative evaluation, she remained asymptomatic, and radiographs showed significant periapical healing with adequate bone formation. CONCLUSION: These results suggest that microsurgical management using the GTR technique with collagen membrane and xenograft, contributes to bone regeneration.

Unraveling the Life History of Past Populations through Hypercementosis: Insights into Cementum Apposition Patterns and Possible Etiologies Using Micro-CT and Confocal Microscopy.

The "teeth-as-tools" hypothesis posits that Neanderthals used their anterior teeth as a tool or a third hand for non-dietary purposes. These non- or para-masticatory activities (e.g., tool-making or food preparation prior to ingestion) have also been described in other past and extant human populations, and other Primates. Cementum is the mineralized tissue that covers the tooth root surface and anchors it to the alveolar bone. Under certain conditions (e.g., mechanical stress, infection), its production becomes excessive (i.e., beyond the physiological state) and is called 'hypercementosis'. Several studies in dental anthropology have established a correlation between the teeth-as-tools and hypercementosis. The present work aims to characterize the different patterns of cementum apposition on archeological teeth and discuss their supposed etiology. Using microtomography and confocal microscopy, the patterns of cementum apposition (i.e., thickness, location, and surface characteristics) were analyzed in 35 hypercementotic teeth (Sains-en-Gohelle, France; 7th-17th c. A.D.). Four groups were identified with distinct hypercementosis patterns: (1) impacted, (2) infected, (3) hypofunctional, and (4) hyperfunctional teeth. Characterizing hypercementosis can contribute to documenting the oral health status (paleopathology) and/or masticatory activity of individuals, even from isolated teeth. This has implications for the study of fossil hominins, particularly Neanderthals, known for their use of anterior teeth as tools and frequent and substantial occurrence of hypercementosis.

Endodontic Dentistry: Analysis of Dentinal Stress and Strain Development during Shaping of Curved Root Canals.

BACKGROUND: Endodontic shaping causes stress and strain in the root canal dentin. Dentin microcracks have the potential to be later followed by root fractures occurring under the occlusal load. The aim of our research was to theoretically determine the values of such dentinal states of stress and strain during the endodontic shaping of curved root canals using finite element analysis (FEA). METHODS: To highlight the stress concentrations in dentin, two geometric models were created considering the volume of the curved dental root and the contact between the endodontic file and the root canal walls. The application of forces with different values was simulated both on a uniform curved root canal and on a root canal with an apical third curvature of 25° as they would be applied during the preparation of a root canal. RESULTS: In the case of the first model, which was acted upon with a force of 5 N, the deformations of the root canal appeared along the entire working length, reaching the highest values in the apical third of the root, although there were no geometric changes in the shape of the root canal. Regarding the second root model, with an apical third curvature of 25°, although the applied force was 2 N, the deformations were accompanied by geometric changes in the shape of the root, especially in the upper part of the apical third. At a higher force of 7 N exerted on the endodontic file, the geometric shape changed, and the deformation reached extreme critical values. The resulting tensile stresses appearing in the experimental structure varied similarly to the deformations. CONCLUSIONS: Significant stress and strain can develop, especially in the apical third of curved root canals during their shaping, and the risk of cracks is higher for endodontically treated teeth presenting severe curvatures in the apical third of the root.

Furcation area and root proximity of molars as a risk indicator of periodontitis: a cone­beam computed tomography-based study.

OBJECTIVES: This study assessed the root proximity in molars and the furcation area (FA) in the first root separation point (RSP) using cone­beam computed tomography (CBCT) and evaluated the association between the furcation area of molars and periodontal status of the patients. METHODS: A total of 264 molar teeth in 66 participants were included in the study. The control group consisted of 110 molar teeth of participants, and 154 molar teeth were included in periodontitis group, which consisted of only stage II and III periodontitis patients. FA, RSP, and root proximities were measured in axial slices, and bone resorption rates were measured in sagittal slices. RESULTS: Both maxillary and mandibular molar groups had significantly less FA in periodontitis group than in controls (p < 0.005), and there were significant relationships between the degree of bone resorption in molars and FA and furcation grades (p < 0.001). According to regression analysis, the risk of periodontitis increased by 1.011 times as total FA decreased (p < 0.001), and periodontitis risk of maxillary molar was 1.693 times higher than mandibular molars but not found to be statistically significant (p = 0.152). When assessing the root proximity between molar teeth, maxillary molars showed significantly higher root proximity in CEJs than mandibular molars in both periodontitis and control groups (p < 0.05). CONCLUSIONS: The results indicate that the association between FA and the degree of bone resorption and root proximity of maxillary molars might be considered as a risk indicator for bone resorption in molars and might play a role during disease progression.

Dental Root Injuries Caused by Osteosynthesis Screws in Orthognathic Surgery-Comparison of Conventional Osteosynthesis and Osteosynthesis by CAD/CAM Drill Guides and Patient-Specific Implants.

BACKGROUND/AIM: The primary aim was to evaluate the prevalence and localisation of dental injuries caused by osteosynthesis screws during orthognathic surgery, comparing two different CAD/CAM planning/surgical approaches through retrospective evaluation of post-operative computed tomography. MATERIAL AND METHODS: This study considered all patients who underwent orthognathic surgery from 2010-2019. The examination for dental root injuries between conventional osteosynthesis (Maxilla conventional cohort) and osteosynthesis with patient-specific implant (Maxilla PSI cohort) was performed by evaluating the post-operative CT scans. RESULTS: A total of 126 patients were included in the study. Among the 61 patients of the Maxilla conventional cohort, 10 dental root injuries in 8 patients (13.1%) were detected in the post-operative CT scan, representing 1.5% (n = 10/651) of the osteosynthesis screws inserted in proximity of the alveolar crest. No dental injury occurred following osteosynthesis in the 65 patients of the Maxillary PSI cohort (n = 0/773 screws) (p < 0.001). During a mean follow-up period of 13 months after primary surgery, none of the injured teeth showed evidence of periapical alterations and no endodontic treatments were necessary. CONCLUSIONS: Maxillary positioning using CAD/CAM-fabricated drill/osteotomy guide and osteosynthesis with PSI can significantly reduce the risk for dental injury compared to the conventional procedure. However, the clinical significance of the detected dental injuries was rather minor.

Accuracy of a 3D printed sleeveless guide system used for fiber post removal: An in vitro study.

OBJECTIVES: The removal of fiber post is often a challenging task. A 3D printed assembled sleeveless system that guides the head of the handpiece instead of the drill was developed to address this issue. This study aimed to evaluate the accuracy of this novel guide system using an in vitro approach. METHODS: A standard maxillary typodont was digitized. The right first molar, the right central incisor, the left first premolar, and the left second molar in the digitized dentition were virtually crown-amputated. Four cylinders (diameter: 6 mm, height: 12 mm) were positioned along the directions of the main roots of these teeth to establish the virtual test model. Ten copies of the test model were printed using light-polymerizing resin. Four assembled sleeveless guide systems targeting the cylindrical axes were designed and printed using titanium alloy. One senior prosthodontist performed the drilling task targeting each cylindrical axis aided by the guide system or freehand (20 teeth each). The drilled models were scanned. The coordinates of the centers of all perforations and circular bases on the coronal and apical surfaces were obtained. The linear and angular deviations between the actual drilling path and the cylindrical axis for each tooth were calculated and analyzed. RESULTS: The guided group exhibited significantly smaller linear and angular deviations than the freehand group (coronal linear deviation: 0.19 ± 0.09 mm vs. 0.35 ± 0.18 mm, p = 0.0012; apical linear deviation: 0.54 ± 0.19 mm vs. 1.71 ± 0.51 mm, p < 0.001; angular deviation: 2.67 ± 1.07° vs. 8.48 ± 2.86°, p < 0.001). CONCLUSION: The accuracy of the 3D printed assembled sleeveless guide system used for fiber post removal is superior to that of the freehand method within the limits of an in vitro design. CLINICAL SIGNIFICANCE: For the removal of fiber posts, the present 3D printed sleeveless guide system can provide better accuracy that the conventional freehand method. This may justify the diffusion of the guided technique for fiber post removal.

Relationship between Physiological Resorption of Primary Molars with Its Permanent Successors, Dental Age and Chronological Age.

The aim of the present study was to analyse root resorption of the primary mandibular molars and their relationship with their permanent successors and the age of the patient. METHODS: The sample consisted of 408 digital panoramic radiographs. The mesial and distal crown-to-root ratios (CRR) of #74 and #75 were calculated by dividing the measures of the length of each root by its coronal height. The Demirjian formation stage of the premolar was established, and dental age was determined. A descriptive and statistical analysis was performed using SPSS to determine the correlation between the variables (Pearson's correlation coefficient) and to identify the differences between them (Student's t-test), with a confidence level of 95%. RESULTS: 723 molars were measured, and tables of CRR depending on dental and chronological age were obtained. The CRR decreased with increasing dental and chronological age, but not uniformly. The CRR of #74 and #75 decreased slightly when the successor premolar was in the initial stages of formation. Gender differences were obtained with respect to chronological age, mainly in girls, because the root resorption of #74 was always more advanced, and the formation of the #34 more advanced. CONCLUSIONS: Root resorption of the molar is slight and progressive when the successor premolar begins formation until stage D, and becomes higher starting at stage E. It is possible to determine the state of the child's maturation and the CRR according to dental and chronological age.

Application of holography and augmented reality based technology to visualize the internal structure of the dental root - a proof of concept.

BACKGROUND: The Augmented Reality (AR) blends digital information with the real world. Thanks to cameras, sensors, and displays it can supplement the physical world with holographic images. Nowadays, the applications of AR range from navigated surgery to vehicle navigation. DEVELOPMENT: The purpose of this feasibility study was to develop an AR holographic system implementing Vertucci's classification of dental root morphology to facilitate the study of tooth anatomy. It was tailored to run on the AR HoloLens 2 (Microsoft) glasses. The 3D tooth models were created in Autodesk Maya and exported to Unity software. The holograms of dental roots can be projected in a natural setting of the dental office. The application allowed to display 3D objects in such a way that they could be rotated, zoomed in/out, and penetrated. The advantage of the proposed approach was that students could learn a 3D internal anatomy of the teeth without environmental visual restrictions. CONCLUSIONS: It is feasible to visualize internal dental root anatomy with AR holographic system. AR holograms seem to be attractive adjunct for learning of root anatomy.

Variaciones anatómicas en primer y segundo molar permanente mandibular con tratamiento endodóntico, evaluadas con tomografía computarizada de haz cónico. Revisión narrativa / Anatomical variations in the first and second permanent mandibular molar with endodontic treatment, evaluated with cone-beam computed tomography. Narrative review

Introducción: Una de las dificultades de los tratamientos endodónticos son las variaciones anatómicas de las raíces y sistema de canales radiculares. Existe poca información sobre prevalencia y distribución espacial de estas variaciones en casos reportados con CBCT (del inglés Cone-Beam Computed Tomography). El propósito de la presente revisión fue analizar las variaciones anatómicas en primer y segundo molar permanente mandibular con tratamiento endodóntico evaluadas con CBCT. Materiales y métodos: Se seleccionaron artículos con casos de tratamiento endodóntico en primer o segundo molar permanente mandibular. Se determinaron el número, distribución espacial de variaciones anatómicas radiculares y canales. Además, el número y tipo de alteraciones de forma. Resultados: La mayor prevalencia del número y distribución espacial de raíces en primer molar fue de tres raíces [1M (mesial), 2D (distal)] con un 76,5% y cuatro raíces (2M, 2D) con un 55,6% en segundo molar. La mayor prevalencia del número y distribución de canales radiculares para el primer y segundo molar fue de cuatro canales: 1mesiovestibular, 1mesiolingual, 1distovestibular y 1distolingual, con un 30% y 90,9% de los casos seleccionados respectivamente. La distribución de alteraciones de forma fue de 8,7% para geminación y de 2,1% para taurodontismo. Conclusiones: La variación anatómica de raíces del primer y segundo molar inferior permanente con más frecuencia fue de tres y cuatro respectivamente. La variación anatómica de canales con más frecuencia fue de cuatro: 2M y 2D. El número de alteraciones de forma fueron poco frecuentes, presentando geminaciones y taurodontismo, solo en segundos molares.

Introduction: One of the difficulties of endodontic treatments is the anatomical variations of the roots and the root canal system. There is little information on the prevalence and spatial distribution of these variations in cases reported with CBCT (Cone-Beam Computed Tomography). The purpose of this review was to analyze the anatomical variations in the mandibular first and second permanent molars with endodontic treatment evaluated with CBCT. Materials and methods: Articles with cases of endodontic treatment in the first or second permanent mandibular molar were selected. The number, spatial distribution of anatomical variations of roots and canals were determined. The number and type of shape alterations were also determined. Results: The highest prevalence regarding number and spatial distribution of root in the first molar was three roots (1M (mesial), 2D (distal)) with 76.5% and four roots (2M, 2D) with 55.6% in second molar. The highest prevalence regarding number and distribution of root canals for the first and second molars was four channels: 1 mesiobuccal, 1 mesiolingual, 1 distobuccal and 1 distolingual, with 30% and 90.9% of the cases selected, respectively. The distribution of shape alterations was 8.7% for gemination and 2.1% for taurodontism. Conclusions: The anatomical variation of roots of the first and second permanent lower molars with the most frequency was three and four respectively. The most frequent anatomic variation of channels was four: 2M and 2D. The number of shape alterations were less frequent, presenting geminations and taurodontism, only in second molars.

Association between root taper and root proximity of single-rooted teeth with periodontitis: a cone-beam computed tomography based study.

This study aimed to determine the association between the root taper and proximity of single-rooted teeth with periodontitis using cone-beam computed tomography (CBCT). CBCT images of 362 single-rooted teeth from 37 patients were evaluated. This case-control study analyzed 17 participants with stage II and III periodontitis, (n = 161 teeth, periodontitis group) and 20 participants with healthy periodontium (n = 201 teeth, control group). Multiplanar reconstructions were used for proximity measurements, and cross-sectional images for calculating the angle of the root tapers. Root proximity, root length, and root taper were measured. Multivariate binary logistic regression analysis was used to determine association with periodontitis. In the periodontitis group, the upper lateral root-taper was 18.33° ± 3.25° and was significantly higher when compared to the control group (p = 0.001). The root taper of the lateral incisor was associated with the diagnosis of periodontitis (p = 0.01) with an odds ratio of 1.541 according to regression analysis. Root length was also identified as a potential protective parameter. The risk of being diagnosed with periodontitis decreases when root length increases by 0.785 times (p = 0.043). Upper canines in the periodontitis group presented shorter root lengths (p = 0.039) and higher root tapers (p = 0.01). Also, mandibular canines were closer form adjacent teeth in the periodontitis group (p = 0.042). This study indicated that short-root and increased root-taper at specific teeth could be considered as risk indicators for periodontitis.

Hsa-miRNA-143-3p regulates the odontogenic differentiation of human stem cells from the apical papilla by targeting NFIC.

AIM: To evaluate the effects of hsa-miRNA-143-3p on the cytodifferentiation of human stem cells from the apical papilla (hSCAPs) and the post-transcriptional regulation of Nuclear factor I-C (NFIC). METHODOLOGY: miRNA expression profiles in human immature permanent teeth and during hSCAP differentiation were examined. hSCAPs were treated with miR-143-3p overexpression or silencing viruses, and the proliferation and odontogenic and osteogenic differentiation of these stem cells, and the involvement of the NFIC pathway, were investigated. Luciferase reporter and NFIC mutant plasmids were used to confirm NFIC mRNA as a direct target of miR-143-3p. NFIC expression analysis in the miR-143-3p overexpressing hSCAPs was used to investigate whether miR-143-3p functioned by targeting NFIC. Student's t-test and chi-square tests were used for statistical analysis. RESULTS: miR-143-3p expression was screened by microarray profiling and was found to be significantly reduced during hSCAP differentiation (p < .05). Overexpression of miR-143-3p inhibited the mineralization of hSCAPs significantly (p < .05) and downregulated the levels of odontogenic differentiation markers (NFIC [p < .05], DSP [p < .01] and KLF4 [p < .01]), whereas silencing of miR-143-3p had the opposite effect. The luciferase reporter gene detection and bioinformatic approaches identified NFIC mRNA as a potential target of miR-143-3p. NFIC overexpression reversed the inhibitory effect of miR-143-3p on the odontogenic differentiation of hSCAPs. CONCLUSIONS: miR-143-3p maintained the stemness of hSCAPs and modulated their differentiation negatively by directly targeting NFIC. Thus, inhibition of this miRNA represents a potential strategy to promote the regeneration of damaged tooth roots.

A comparison of the effects of two orthodontic techniques in the orthodontic treatment of sagittal skeletal patterns.

OBJECTIVE: To compare the differences in the amount of dental root resorption (DRR) measured using different orthodontic techniques in the orthodontic treatment of patients with different sagittal skeletal patterns. METHODS: Ninety-three patients undergoing orthodontic treatment were randomly divided into group A (n=46) and group B (n=47). Group A was treated with bracketless invisible orthodontics and group B was treated using the self-ligating fixed orthodontic technique. Cone beam computed tomography (CBCT) was used to measure the amount of DRR in the patients with different sagittal skeletal patterns receiving the orthodontic treatment. RESULTS: After the treatment, the amounts of DRR in the maxillary and mandibular canines in both groups were lower than they were in the other 4 tooth positions (P < 0.05). The amount of DRR in the maxillary and mandibular canines in the patients with skeletal class I in both groups was lower than it was at the other four tooth positions (P < 0.05). The amount of DRR in the maxillary central incisors and maxillary canines in the patients with skeletal class II in group A was higher than it was in group B, but the amount of DRR in the mandibular canines in group A was lower than it was in group B (P < 0.05). The amounts of DRR at the six tooth positions in the patients with skeletal class III in group A were higher than the amounts in group B (P < 0.05). CONCLUSION: DRR occurs in patients with different sagittal skeletal patterns undergoing the two orthodontic techniques in the orthodontic treatment, but there are differences in the amount of DRR among the patients with different sagittal skeletal patterns receiving the orthodontic treatment. Clinically, the orthodontic method should be selected based on the type of patient.

Pulpal outcomes in orthodontic tooth movement in diabetes mellitus.

Diabetes mellitus impairs angiogenesis and tissue reorganization during orthodontic tooth movement (OTM). Thus, this study evaluated pulpal outcomes in orthodontic tooth movement through metabolic changes in diabetes. Male Wistar rats were used, and the in vivo study design consisted of four groups (n = 10/group): C-non-diabetic animals not subjected to orthodontic tooth movement; D-diabetic animals not subjected to orthodontic tooth movement; OTM-non-diabetic animals subjected to orthodontic tooth movement; and D + OTM-diabetic animals subjected to orthodontic tooth movement. In addition, the pulps of the distovestibular root (DV) and mesiovestibular root (MV) were assessed by histomorphometric analyses and immunoexpression of the RANKL/OPG system. Pulpal analysis of the MV root showed an increase in blood vessels in diabetic animals. Inflammatory infiltrate and fibroblastic cells were elevated in diabetic animals with tooth movement in the DV and MV roots. In the DV and MV roots, diabetic rats with OTM showed a reduction in birefringent collagen fibers. The immunostaining for RANKL was higher in the pulp tissue of OTM in diabetic and non-diabetic animals. It was concluded that the pulp tissue has less adaptive and repair capacity during OTM in diabetes. Orthodontic strength can alter the inflammatory processes in the pulp.

CRISPR-cas system in the acquisition of virulence genes in dental-root canal and hospital-acquired isolates of Enterococcus faecalis.

Enterococcus faecalis is one of the important causative agents of nosocomial and life-threatening infections in human. Several studies have demonstrated that the presence of CRISPR-cas is associated with antibiotic susceptibility and lack of virulence traits. In this study, we aimed to assess the phenotypic and genotypic virulence determinants in relation to CRISPR elements from the dental-root canals and hospital-acquired isolates of E. faecalis. Eighty-eight hospital-acquired and 73 dental-root canal isolates of E. faecalis were assessed in this study. Phenotypic screening of the isolates included biofilm formation, and gelatinase and hemolysis activities. Genotypical screening using PCR was further used to evaluate the presence of CRISPR elements and different virulence-associated genes such as efaA, esp, cylA, hyl, gelE, ace, ebpR, and asa1. Biofilm formation, gelatinase, and hemolysis activities were detected in 93.8%, 29.2%, and 19.2% of the isolates, respectively. The most prevalent virulence-associated gene was ace, which was followed by efaA, whereas cylA was the least identified. The presence of CRISPR1-cas, orphan CRISPR2, and CRISPR3-cas was determined in 13%, 55.3%, and 17.4% of the isolates, respectively. CRISPR elements were significantly more prevalent in the dental-root canal isolates. An inverse significant correlation was found between CRISPR-cas loci, esp, and gelE, while direct correlations were observed in the case of cylA, hyl, gelE (among CRISPR-loci 1 and 3), asa1, ace, biofilm formation, and hemolysis activity. Findings, therefore, indicate that CRISPR-cas might prevent the acquisition of some respective pathogenicity factors in some isolates, though not all; so selective forces could not influence pathogenic traits. Abbreviations: BHI: brain-heart infusion agar; CRISPRs: Clustered regularly interspaced short palindromic repeats; Esp: Cell wall-associated protein; ENT: ear-nose-throat; ICU: intensive care units; OD: optical densities; PCR: polymerase chain reaction; SDS: sodium dodecyl sulfate; UTI: urinary tract infection.

Three-dimensional-guided removal and preparation of dental root posts-concept and feasibility.

PATIENTS: This case report presents a novel method to remove glass fiber-reinforced composite root posts in a minimally invasive way while simultaneously shaping the canal for a new post-endodontic restoration. A multi-morbid, handicapped 62-year-old patient was referred with a horizontally fractured maxillary incisor presenting approximately 1 mm residual coronal tooth height. Endodontic revision was necessary, which required removal of a glass fiber-reinforced composite post. A cone-beam computed tomography (CBCT) scan was imported into conventional implant-planning software and matched to a stone cast of the intraoral situation. Position, length, and axis of the future post were planned virtually. Based on this planning, a tooth-supported splint was three-dimensionally (3D) printed. This splint allowed use of a 2.2-mm spiral drill for removal of the fractured post and shaping of the root canal for a new cast post-and-core. This metal post-and-core was adhesively cemented and prepared for a zirconia single crown veneered in the labial aspect. DISCUSSION: This method currently requires use of CBCT-based, ionizing 3D imaging. Additional refinements to this approach can be made regarding spiral drill design and coating as well as regarding the post-and-core workflow. CONCLUSIONS: 3D-guided post-endodontic management is feasible. More research is needed to balance higher radiation doses against therapeutic success.

Analysis of root canal system of maxillary first and second molars and their correlations by cone beam computed tomography.

BACKGROUND/PURPOSE: Understanding the root canal systems of molars and the association of root canal system in adjacent or contralateral molars is important for dental practice. This study aimed to use cone-beam computed tomography (CBCT) to analyze the morphology similarity of root canal systems in the maxillary first and second molars. METHODS: CBCT images of 1741 maxillary molars in a total of 519 patients were blindly examined to analyze the correlation of root canal systems between maxillary first and second molars as well as the bilateral first and second molars. RESULTS: The most common type in maxillary first molars is 3R4C (3 roots/4 canals), whereas in maxillary second molars is 3R3C.The symmetry in type of root canals in bilateral maxillary first and second molars were 87.36% and 79.85%, respectively. The similarities of root canal system in adjacent maxillary first and second molars were 53.07% (right side) and 52.58% (left side). The concurrence of MB2 canal in bilateral maxillary first molars is 77.8%, and 35.97% in maxillary second molars. In the 110 patients with MB2 canal in bilateral maxillary second molars, the chance of bilateral MB2 canals in their maxillary first molar is almost 100%. CONCLUSION: Maxillary first molars have higher prevalence of 3R4C than second molars. The symmetry in bilateral maxillary molars is higher than the similarity in adjacent maxillary first and second molars. Application of CBCT analysis of root canal system can improve endodontic treatment outcomes. The correlation of root canal system between teeth is useful for genetic linkage.

Endodontic and Surgical Management of Iatrogenic Root Injury Caused by Orthodontic Miniscrew Placement: A Case Report.

One of the potential serious complications, associated with the inter-radicular placement of an orthodontic miniscrew, is root injury. This article reports the endodontic and surgical treatments of an iatrogenic root perforation in a mandibular first molar caused by the placement of an orthodontic miniscrew anchorage. The 24-month follow-up showed a successful treatment outcome.

Facial cutaneous lesions of dental origin: A case series emphasizing the awareness of the entity and its medico-legal consequences.

INTRODUCTION: Facial cutaneous lesions of dental origin are rare and hence the correct diagnosis is usually missed on the initial presentation to the surgeon. We present the largest series in the surgical literature to increase the awareness to this entity and emphasize that the wrong diagnosis may lead to medico-legal claims. PATIENTS AND METHODS: This is a retrospective study of 28 patients seen between 1994 and 2017. RESULTS: The series had one child and 27 adults. The presentation varied and included: a nodule, a subcutaneous soft mass, a sinus, an abscess, a cyst, a pigmented skin lesion and a scar. Thirteen cases had an initial wrong diagnosis and of these 4 had surgery to the lesion. Two out of the 4 surgically treated lesions ended with medico-legal claims. CONCLUSIONS: The surgeon should be aware of this rare entity and have a high index of suspicion. Dental treatment is curative and there is no need to operate the facial lesion. The wrong diagnosis and unnecessary surgery may lead to medico-legal claims.