Morphology and root canal configuration of maxillary canines: a systematic review and meta-analysis.

BACKGROUND: This study assessed the internal morphology of maxillary canines (MxC) through a systematic review of existing literature. METHODS: Research articles up to June 2024 were retrieved from five electronic databases (MEDLINE via PubMed, Embase, Scopus, LILACS, and Cochrane). Predefined search terms and keywords were used, and potential studies were identified by cross-referencing and bibliographies of the selected articles reviewed. RESULTS: Two hundred studies were identified, 73 duplicates were removed, 127 records were screened, and 113 were removed after consultation of title and abstract. After full-text consultation and hand searching, finally 22 studies were included. Using the method for describing the root canal configuration (RCC) of Briseño Marroquín et al. (2015) and Vertucci (Ve) (1984), the most frequently reported RCC of MxC were 1-1-1/1 (Ve I, 75.4-100%), 2-2-1/1 (Ve II, 0.1-20%), 1-2-1/1 (Ve III, 0.1-11.6%), 2-2-2/2 (Ve IV, 0.1-0.4%), 1-1-2/2 (Ve V, 0.1-2.4%), 2-1-2/2 (Ve VI, 0.5-1.2%), and 1-2-1/2 (Ve VII, 0.1-0.2%). The meta-analysis of six studies (Europe/Asia) showed that a significantly higher number of RCC of 2-2-1/1 (Ve II) (OR [95%CI] = 1.34 [0.53, 3.41]), 1-2-1/1 (Ve III) (OR [95%CI] = 2.07 [1.01, 4.26]), and 1-1-2/2 (Ve V) (OR [95%CI] = 2.93 [1.07, 8.07]), were observed in males, and 2-2-2/2 (Ve IV) (OR [95%CI] = 0.08 [0.00, 4.00]) in females. No sex differences in the RCC of 1-1-1/1 (Ve I) and 1-2-1/2 (Ve VII) were observed. CONCLUSIONS: Cone beam computed tomography is the most frequently used method for research on the RCC of MxC. Despite the high prevalence of type 1-1-1/1 (Ve I) RCC in MxC, clinicians should remain vigilant for more complex and sex-differentiated patterns in up to 25% of cases to prevent endodontic treatment complications or failures.

[Transverse characteristics of normodivergent patients in different sagittal skeletal patterns].

PURPOSE: This study aimed to measure and analyze the transverse indicators of normodivergent patients with different sagittal skeletal malocclusions, to explore the transverse characteristics of different sagittal skeletal malocclusions. METHODS: Lateral cephalograms and CBCT of 90 normodivergent patients with skeletal Class Ⅰ, Ⅱ and Ⅲ in their permanent dentition were collected. Dolphin software was applied to measure the widths of the basal bone, alveolar bone, dental arch and buccolingual inclination angle of the corresponding teeth in the maxillary and mandibular canine, premolar and molar areas. SPSS 22.0 software package was applied for statistical analysis of the data. RESULTS: The widths of the mandibular basal bone in canine, premolar and molar areas of skeletal Class Ⅲ were (27.15±2.74), (39.30±2.82) and (59.97±2.93) mm, respectively. The widths of the mandibular alveolar bone of skeletal Class Ⅲ were (25.38±1.78), (34.51±2.28) and (47.72±2.73) mm, respectively. The dental arch widths of the maxillary premolar and mandibular canine areas of skeletal Class Ⅲ were (48.70±2.35) and (30.69±2.31)mm, respectively. The above data of skeletal Class Ⅲ were significantly larger than those of skeletal Class Ⅰ and Ⅱ(P＜0.01). The dental arch widths of the maxillary canine, maxillary molar and mandibular molar areas of skeletal Class Ⅲ were (38.88±1.90), (59.51±3.40) and (56.01±2.86)mm, respectively, which were significantly larger than those of skeletal Class Ⅱ(P＜0.05). The maxillomandibular width difference of basal bone in the canine, premolar and molar areas of skeletal Class Ⅲ were (4.69±2.84), (2.31±2.39) and (3.27±2.05) mm, respectively, which were significantly less than that of skeletal Class Ⅰ and Ⅱ(P＜0.01). Compared with skeletal Class Ⅰ, the maxillary canines and first molars of skeletal Class Ⅱ had larger lingual inclination level, while the maxillary first premolars and first molars of skeletal Class Ⅲ had larger buccal inclination level, the mandibular canines and the mandibular first premolars of skeletal Class Ⅲ had larger lingual inclination level(P＜0.01). CONCLUSIONS: For normodivergent patients, the width of the mandibular base bone, alveolar bone, and maxillary and mandibular dental arch in skeletal Class Ⅲ is the widest, which is more likely to have width discrepancy in basal bone. In skeletal Class Ⅲ, the maxillary teeth are buccally inclined, and the mandibular teeth are ingually inclined. In skeletal Class Ⅱ, the maxillary teeth are lingually inclined, and the mandibular teeth are compensatory upright.

Anatomical characteristics of different tooth groups. Effect on in-office bleaching treatment

AIM: The objective of the present study was to investigate the association between the anatomical characteristics of different tooth groups and the diffusion and bleaching effect of hydrogen peroxide (H2O2). MATERIALS AND METHODS: Computed tomography (CT) images from five patients were used to assess the hard tissue thickness and pulp volume (PV) of four tooth groups: lower (mandibular) incisors (LI), upper (maxillary) incisors (UI), canines (C), and premolars (PM). Additionally, 80 bovine tooth disks were divided into four groups (n = 20) to match the thickness of each tooth group studied. All the specimens were exposed to a 35% H2O2 bleaching gel, with 50 µL applied for 45 min during the first, second, and third sessions. Diffusion was evaluated using the peroxidase enzyme method. Color change analyses (∆E, ∆E00, and ∆WID) were performed after the three application sessions and 7 days after the bleaching treatment using a spectrophotometer. RESULTS: The PM group showed greater thickness and PV, followed by the C, UI, and LI groups (P 0.001). The LI group had six times greater H2O2 diffusion compared with the PM group (P 0.001), while the PM group exhibited a PV nine times larger than the LI group. Furthermore, the LI and UI groups achieved color saturation with one fewer session than the C and PM groups. CONCLUSIONS: Specific tooth groups have anatomical characteristics that interfere with bleaching treatment in terms of the diffusion and whitening effect of H2O2. Furthermore, the diffusion capacity of H2O2 was inversely proportional to the thickness of the tooth groups.

Marginal Gingival Thickness Assessment in Three- To Six-Year-Old Preschool Children.

Purpose: Although gingival thickness has been extensively studied in permanent dentition, the literature regarding marginal gingival thickness in primary dentition is insufficient. The purpose of this study was to assess the variations in marginal gingival thickness in preschool-age children. Methods: A cross-sectional study of 4,109 primary teeth was conducted. Using a reamer, the transgingival probing method was employed to assess marginal gingival thickness in healthy preschoolers. Inter-examiner and intra-examiner reproducibility were assessed via the intraclass correlation coefficient. Results: Descriptive statistics revealed that primary maxillary left second molars had the highest mean marginal gingival thickness (1.06 mm), whereas primary mandibular right central incisors had the lowest mean marginal gingival thickness (0.74 mm). Gender-based independent sample t-tests revealed significant differences in the values of primary maxillary right canines (females had greater values than males; P=0.03) and primary mandibular right first molars (males had greater values than females; P=0.01). An inter-arch comparison revealed significant differences between the primary second molars (maxillary more than mandibular; P=0.001). Conclusions: This study reports the first documented marginal gingival thicknesses of primary dentition. It reveals substantial variations in the values of primary maxillary right canines and primary mandibular right first molars and between primary maxillary and mandibular second molars.

Assessment of the unwanted tooth movement associated with an extended maxillary fixed retainer (3D analysis).

BACKGROUND: Posttreatment changes after orthodontic treatment are challenging. One of the main reasons for such a phenomenon is the lack of patient compliance with removable retainers especially in the maxillary arch, due to palatal coverage, deterioration of speech, decreased masticatory efficiency, and loss of retainers. Fixed retainers have been introduced to overcome patient compliance and provide longer stable results. However, teeth still show movements when a six-unit fixed retainer is in place. Thus, in this study, an eight-unit fixed retainer was evaluated in an attempt to eliminate unwanted movements. THE AIM OF THIS RESEARCH: was to assess short-term positional changes associated with an eight-unit extended maxillary fixed retainer. MATERIALS AND METHODS: A single-arm clinical trial was conducted to address the aim of the study. This research was approved by the institutional review board of the Faculty of Dentistry, Alexandria University (IORG:0008839, No-0479-8/2022). The registration date of this study was 5/06/2023. Twenty-eight patients (19.8 ± 4.5 years) who had finished the active orthodontic phase and started retention had an eight-unit extended maxillary fixed retainer that was bonded to the palatal surface of the maxillary incisors, canines, and the first premolars or the second premolars. Pre-retention and one-year post-retention intra-oral scans were made to produce STL files that were superimposed to determine the amount of tooth change. Additionally, analysis of digital casts and lateral cephalometric radiographs was performed. RESULTS: Statistically significant changes in all planes and the rotation of teeth after one year of retention were found. The upper right lateral incisor exhibited the most evident change in the vertical plane, while the upper right central incisor exhibited the greatest change overall. Minimal changes in the cast measurements were observed. Lateral cephalometric measurements showed minimal changes after one year of retention, and these changes were not statistically significant except in the interincisal angle and the angle between the upper incisor and the line connecting the A-point to the pogonion. CONCLUSION: Increasing the extension of maxillary fixed retainers did not eliminate unwanted tooth movement in the first year of retention.

Treatment options for impacted maxillary canines and occurrence of ankylotic and resorptive processes: a 20-year retrospective study.

BACKGROUND: This 20-year retrospective study aimed to evaluate the treatment methods used in patients with impacted maxillary permanent canines and to determine the occurrence of ankylotic and resorptive processes and their association with potential risk factors. METHODS: The cohort consisted of 351 consecutive Caucasian patients (120 males and 231 females, mean age 18.4 and 19.9 years, respectively) with 420 impacted maxillary permanent canines. CT and CBCT findings were subsequently confirmed during surgery. Statistical analyses were performed by the generalized linear models, Pearson x2 and Fisher exact tests using the statistical programs R and Statistica v. 14. RESULTS: A total of 273 (65.0%) impacted canines were aligned in the dental arch by orthodontic traction after surgical exposure, this treatment was predominant in patients under 20 years of age. Surgical extraction was performed in 115 (27.2%) impacted canines and was more common in older patients. Ankylotic changes were recorded in 61 (14.5%) impacted canines. The probability of ankylosis increased with age, particularly after the patient's 20th year of life (p < 0.001). Patients were 1.2% likely to develop ankylosis at age 15 years, 4.3% at age 20 years, 14.1% at age 25 years, and 96.8% at age 45 years. Invasive cervical root resorption (ICRR) was found in 8 (1.9%) canines. In 4 canines (1.0%), root ankylosis in addition to ICRR was observed. In contrast to ankylosis, whose frequency of occurrence increased with age, the occurrence of ICRR resulting from PDL damage during surgery was more typical in younger patients. Canines in a high position above the root apices of the adjacent teeth, with a horizontal inclination of the longitudinal axis, with the crown located deep in the center of the alveolar bone and with labiopalatal position, should be considered critically impacted canines with a high risk to failure of orthodontic traction. CONCLUSION: In conclusion, the treatment of impacted canines depends mainly on the age of the patient, and the position and inclination of the longitudinal axis of the impacted tooth. To select an adequate treatment method, we recommend CBCT examination, which allows a precise analysis of the position of impacted canines.

A hierarchical deep learning approach for diagnosing impacted canine-induced root resorption via cone-beam computed tomography.

OBJECTIVES: Canine-induced root resorption (CIRR) is caused by impacted canines and CBCT images have shown to be more accurate in diagnosing CIRR than panoramic and periapical radiographs with the reported AUCs being 0.95, 0.49, and 0.57, respectively. The aim of this study was to use deep learning to automatically evaluate the diagnosis of CIRR in maxillary incisors using CBCT images. METHODS: A total of 50 cone beam computed tomography (CBCT) images and 176 incisors were selected for the present study. The maxillary incisors were manually segmented and labeled from the CBCT images by two independent radiologists as either healthy or affected by root resorption induced by the impacted canines. We used five different strategies for training the model: (A) classification using 3D ResNet50 (Baseline), (B) classification of the segmented masks using the outcome of a 3D U-Net pretrained on the 3D MNIST, (C) training a 3D U-Net for the segmentation task and use its outputs for classification, (D) pretraining a 3D U-Net for the segmentation and transfer of the model, and (E) pretraining a 3D U-Net for the segmentation and fine-tuning the model with only the model encoder. The segmentation models were evaluated using the mean intersection over union (mIoU) and Dice coefficient (DSC). The classification models were evaluated in terms of classification accuracy, precision, recall, and F1 score. RESULTS: The segmentation model achieved a mean intersection over union (mIoU) of 0.641 and a DSC of 0.901, indicating good performance in segmenting the tooth structures from the CBCT images. For the main classification task of detecting CIRR, Model C (classification of the segmented masks using 3D ResNet) and Model E (pretraining on segmentation followed by fine-tuning for classification) performed the best, both achieving 82% classification accuracy and 0.62 F1-scores on the test set. These results demonstrate the effectiveness of the proposed hierarchical, data-efficient deep learning approaches in improving the accuracy of automated CIRR diagnosis from limited CBCT data compared to the 3D ResNet baseline model. CONCLUSION: The proposed approaches are effective at improving the accuracy of classification tasks and are helpful when the diagnosis is based on the volume and boundaries of an object. While the study demonstrated promising results, future studies with larger sample size are required to validate the effectiveness of the proposed method in enhancing the medical image classification tasks.

Dentoalveolar bone height in Class I adults with different vertical patterns: A cross-sectional study.

BACKGROUND: Facial divergence during growth and development affects both the anterior and posterior alveolar bone dimensions in the maxilla and mandible, and the dentoalveolar compensation mechanism in severe vertical skeletal discrepancies remains unclear. AIMS: To evaluate the: (1) difference in dentoalveolar heights among subjects with different vertical facial patterns; (2) association between the dentoalveolar bone height and other cephalometric variables; (3) effect of sex on dentoalveolar height measurements. MATERIAL AND METHODS: Non-growing subjects with skeletal Class I (0°

Craniofacial morphology in patients with impacted canine: a case control-study.

BACKGROUND: The objective of this study was to evaluate the risk of maxillary canine impaction through cephalometric evaluation. METHODS: One hundred and eighty-two Caucasian patients (80 males and 102 females) with a mean age of 12.4±0.5 were retrospectively enrolled in the present study. Ninety patients with impacted canines were compared with ninety-two patients with physiologically erupted canines. The following cephalometric variables were analyzed: SNA, ANB, SN-GOME, GO-ME, SP-CL, SELLA TURCICA DEPHT, A-Pt LINE, B-Pt LINE, A-Pt LINE°, B-Pt LINE°, A1s-Pt, A1i-Pt, A1s-Pt°, A1i-PT°, A-SN, B-SN and SN-U1. When applicable, a paired sample t-test was performed to investigate the difference in means between the two sample groups, while the Mann-Whitney Test was used as a non-parametric test in the case of a non-normal distribution of data. Statistical significance was set at P<0.05. RESULTS: The group with impacted canines showed an increase in Go-Me distance, SNA angle and A1s-Pt angle compared with the control group. In addition, the same group showed a decrease in A-SN and SP-Cl distance compared with the control group. CONCLUSIONS: An increase in mandibular length (GO-ME) and SNA angle associated with a reduction in A-Sn distance and interclinoid distance (SP-Cl) were observed in patients with impacted canines.

Effectiveness of different intrusion modes of maxillary anterior teeth with mini-implants in clear aligner treatment: a three-dimensional finite element analysis.

BACKGROUND: The intrusion of maxillary anterior teeth is often required and there are various intrusion modes with mini-implants in clear aligner treatment. The objective of this study was to evaluate the effectiveness of maxillary anterior teeth intrusion with different intrusion modes, aiming to provide references for precise and safe intrusion movements in clinical practice. METHODS: Cone-beam computed tomography and intraoral optical scanning data of a patient were collected. Finite element models of the maxilla, maxillary dentition, periodontal ligaments (PDLs), clear aligner (CA), attachments, and mini-implants were established. Different intrusion modes of the maxillary anterior teeth were simulated by changing the mini-implant site (between central incisors, between central and lateral incisor, between lateral incisor and canine), loading site (between central incisors, on central incisor, between central and lateral incisor, between lateral incisor and canine), and loading mode (labial loading and labiolingual loading). Ten conditions were generated and intrusive forces of 100 g were applied totally. Then displacement tendency of the maxillary anterior teeth and CA, and stress of the PDLs were analyzed. RESULTS: For the central incisor under condition L14 and for the canine under conditions L11, L13, L23, and L33, the intrusion amount was negative. Under other conditions, the intrusion amount was positive. The labiolingual angulation of maxillary anterior teeth exhibited positive changes under all conditions, with greater changes under linguoincisal loading. The mesiodistal angulation of canine exhibited positive changes under labial loading, while negative changes under linguoincisal loading except for condition L14. CONCLUSIONS: The intrusion amount, labiolingual and mesiodistal angulations of the maxillary anterior teeth were affected by the mini-implant site, loading site, and loading mode. Labial and linguoincisal loading may have opposite effects on the intrusion amount of maxillary anterior teeth and the mesiodistal angulation of canine. The labiolingual angulation of the maxillary incisors would increase under all intrusion modes, with greater increases under linguoincisal loading.

Radiographic evaluation of enamel thickness of permanent teeth: relevance and applicability.

OBJECTIVE: This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. MATERIAL AND METHODS: The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. RESULTS: The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. CONCLUSION: Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.

Impacted maxillary canine: Assessment of prevalence, severity and location of root resorption on maxillary incisors: A retrospective CBCT study.

BACKGROUND: The maxillary permanent canine is one of the most frequently impacted teeth, which often requires multidisciplinary management. A common complication of canine impaction is root resorption of the adjacent dentition. The aim of this retrospective study was to report the prevalence of root resorption of maxillary incisors adjacent to impacted maxillary canines from small volume CBCT images by trained clinicians. A secondary objective was to report the location and severity of root resorption. MATERIAL AND METHODS: CBCT images of patients with impacted maxillary canines (unilateral and bilateral) who attended a joint orthodontic/surgical multidisciplinary clinic were screened. Descriptive statistics were used to investigate associations of patient characteristics and presence of root resorption. Generalized estimating equations (GEE) logistic regression model were used to identify predictors of root resorption. RESULTS: In all, 148 impacted maxillary canines (122 patients) were analysed. The majority of patients were under 18 years of age (71.6%) with impacted canines present in more females (68.2%) than males (31.8%). Maxillary lateral incisors showed the highest prevalence of root resorption (38.5%). The apical region was the most common location of resorption for lateral incisors (20.9%) with a variable degree of severity evident: slight (10.1%), moderate (15.6%), and severe (12.8%). Although no significant predictors of root resorption were identified, a weak association was evident for age and root development. CONCLUSIONS: In this cohort of patients, the roots of maxillary lateral incisors are most likely to suffer from root resorption in the presence of an impacted maxillary canine. Clinicians should consider the extent, location and severity of resorption of adjacent teeth when planning treatment decisions and mechanics in cases of impacted maxillary canines.

Computer-assisted open exposure of palatally impacted canines for orthodontic eruption: A randomized clinical trial.

OBJECTIVE: This randomized clinical trial aimed to assess the feasibility of computer-assisted open exposure of palatally impacted canines. MATERIALS AND METHODS: Patients aged 11-30 years who required orthodontic eruption for the full palatal impaction of their canines were included in this study. Exclusion criteria were psychosocial and dental contraindications of orthodontic treatment, congenital craniofacial disorders, and trauma in the patient's history in the vicinity of the surgical site. Virtual planning software was used to register the intraoral scans and cone-beam computed tomography data and to design a surgical template. In the test group, exposure of the canines was guided by a surgical template, whereas in the control group, the surgeon relied on the surgical plan to localize the impacted canine. The success of the intervention, duration of surgery, and complications, including excessive hemorrhage, damage to the canine or neighboring anatomical landmarks, and postoperative inflammation of the surgical site were assessed. Postoperative pain was reported by the patients using the visual analog pain scale (VAS). RESULTS: Surgery was deemed successful in all patients in both groups. During healing, no complications were observed. The duration of surgery decreased significantly in the test group (4 min 45.1 s ± 1 min 8.4 s) compared to that in the control group (7 min 22.3 s ± 56.02 s). No statistically significant differences were observed between the VAS scores of the two study groups. CONCLUSIONS: The application of virtual planning and static navigation is a viable approach for the open exposure of palatally impacted canines. CLINICAL TRIAL REGISTRATION NUMBER: NCT05909254. CLINICAL SIGNIFICANCE: Computer-assisted surgery is a feasible method for open exposure of palatally impacted canines, which decreases the duration of surgery compared to the freehand method.

Efficacy of WaveOne Gold and ProDesign RT systems in removing filling material: a micro-CT analysis.

The remaining filling material after retreatment can harbor bacteria and organic tissues that can influence the outcome of the therapy. AIM: The aim of this study was to evalúate, by micro-CT, the amount of filling material remaining in the root canal after its removal using WaveOne Gold or ProDesign RT. MATERIAL AND METHOD: Forty human mandibular canines were instrumented with the ProTaper Next system up to the X2 instrument (25.06) and filled with gutta-percha cones and AHPlus. Teeth were divided into 2 groups (n=20): WaveOne Gold 25.07 (WOG) and ProDesign RT 25.08 (PRT) for filling removal, after which they were scanned in a micro-CT device to quantify the volume of remaining filling material. The data were subjected to log 10 transformation, Student 's t-test was performed to account for multiple observationsper sample, significance was set at 5%. RESULTS: Student 's t-test showed that there was no difference between the two systems regarding the volume of remaining filling material in the thirds: apical (p = 0.392), middle (p = 0.065), or cervical (p = 0.918). CONCLUSIÓN: Remaining filling material was present in all groups and both systems were similar in removing root filling material in mandibular canines.

A permanencia de material obturador após o retratamento pode abrigar bactérias e tecidos orgánicos que podem influenciar o resultado da terapia. OBJETIVO: O objetivo deste estudo foi avaliar, por micro-CT, a quantidade de material obturador remanescente no canal radicular após a desobturagdo com WaveOne Gold e ProDesign RT. MATERIAL E MÉTODO: Quarenta caninos inferiores humanos foram instrumentados com o sistema ProTaper Next até o instrumento X2 (25.06) e obturados com cones de guta-percha e AHPlus. Os dentes foram divididos em dois grupos (n=20): WaveOne Gold 25.07 (WOG) e ProDesign RT 25.08 (PRT) e escaneados em micro-CT para quantificagdo do volume de material obturador remanescente. Os dados foram submetidos á transformando log 10, o teste t de Student foi realizado para contabilizar múltiplas observagoes por amostra, a significáncia foi fixada em 5%. RESULTADOS: O teste t de Student mostrou que ndo houve diferenga no volume de material obturador remanescente entre os dois sistemas nos tergos: apical (p = 0,392), médio (p = 0,065) ou cervical (p = 0,918). CONCLUSÃO: O material obturador remanescente estavapresente em todos os grupos e ambos os sistemas foram semelhantes na remogdo do material obturador radicular nos caninos inferiores.

Canine sexual dimorphism in crown and root dimensions: a cone-beam computed tomographic study.

The primary step in forensic odontological analysis is sex determination. The present study is one of the few studies that evaluated the accuracy of the combination of canine tooth root length and crown measurements for sex determination. The study sample comprised 196 cone-be am computed tomographic scans of individuals aged 20-80 years distributed in five age categories: 20-29, 30-39, 40-49, 50-59, and 60+ years old. Different parameters, such as width, length, and ratio measurements for the crown and root of each maxillary and mandibular canine tooth, were examined and recorded. The findings indicated that maxillary canines had greater sex dimorphism ability (87.3%) than mandibular canines (80.6%). Total tooth length and root length of maxillary canine were the most pronounced variables in the differentiation of sex groups. When the combination of the mandibular and maxillary measurements was considered, the accuracy for sex dimorphism was 85.7%. By using ratio variables, the accuracy was reduced to 68.9%. According to the findings of this study, total tooth length and root length are the most discriminant variables of canine teeth. These variables are more reliable sex indicators than crown measurements.

Treatment duration by morphology and location of impacted maxillary canines: A cone-beam computed tomography investigation.

INTRODUCTION: This study aimed to identify whether patients with impacted maxillary canines take longer to treat than orthodontic patients without an impacted canine. We also sought to identify factors that are predictive of increased treatment duration in patients with impacted maxillary canines and treated by surgical exposure. METHODS: A retrospective investigation of 37 patients with an impacted maxillary canine, treated by surgical exposure and fixed appliance therapy, was undertaken. In addition, an age- and sex-matched control group of 39 patients (without impacted canines) was also collected. Patient age, sex, and total treatment duration were recorded. For patients with an impacted canine, patient records and pretreatment cone-beam computed tomography datasets were assessed. Point coordinates identifying relevant landmarks were recorded, and a geometric method was used to calculate variables describing canine location, orientation, and apical morphology. RESULTS: Controlling for age and sex, linear regression identified a statistically significant increase in treatment duration of 46.7 and 41.5 weeks for palatal and labial/midalveolar impacted canines, respectively, vs controls (P <0.002). Age and sex of patients with impacted canines collectively affected treatment duration (P = 0.04), with females of increased age being treated faster than younger males. Rotation of the impacted canine crown had a highly significant effect on treatment duration, with every degree of rotation increasing treatment duration by 0.32 weeks (P <0.001). There was a significant degree of multicollinearity between the other radiographic variables. Collectively, radiographic variables describing canine displacement significantly prolonged treatment duration (P <0.001) and explained 29.8% of the variability in total treatment time. The apical morphology of impacted maxillary canines was significantly associated with increased treatment duration (P = 0.01) and explained 11.3% of the overall treatment variability (P = 0.01). CONCLUSIONS: Increased total treatment duration of surgically exposed impacted maxillary canines is associated with increasing mesiopalatal canine crown rotation, worsening displacement, and hooked apical morphology.

[A two-dimensional photographic and three-dimensional digital dental model comparative analysis in maxillary anterior teeth].

Objective: To assess the accuracy of two-dimensional (2D) photographs in measuring esthetic parameters of the maxillary anterior teeth by comparing them with measurements obtained from three-dimensional (3D) dental models. Methods: A total of one hundred volunteers (49 males, 51 females, aged 18-23 years) were recruited from School and Hospital of Stomatology, Wuhan University from January to February 2024. 3D digital models of their dentitions were obtained using an intraoral scanner, and standardized frontal 2D intraoral photographs were captured with a digital camera. The lengths, widths and width/length ratio of the bilateral incisors, lateral incisors and canines were measured on both the 3D digital models and the 2D intraoral photographs. The width ratios of adjacent maxillary anterior were also calculated on the 2D intraoral photographs and the frontal view of 3D digital models. Results: The widths of lateral incisors [(5.85±0.60) mm] and canines [(4.73±0.71) mm] and the lengths of canines [(8.72±0.96) mm] in the 2D intraoral photographs were significantly lower than those in 3D digital models [(6.65±0.59), (7.76±0.60), (8.90±0.86) mm] (t=-18.24, P<0.001; t=-54.43, P<0.001; t=-4.40, P<0.001), while there were no significant differences in the lengths and widths of the other teeth (P>0.05). The width/length ratios measured from the 2D intraoral photographs for the lateral incisors and canines (0.74±0.08, 0.55±0.08) were significantly lower than those measured in the 3D digital models (0.84±0.09, 0.88±0.09) (t=-19.68, P<0.001; t=-50.21, P<0.001), and the width/length ratio of the central incisors showed no significant difference between the two groups (P>0.05). The width ratios of canines/lateral incisors and lateral incisors/central incisors measured on the 2D intraoral photographs (0.72±0.06, 0.85±0.11) were significantly smaller than those measured in the frontal view of 3D digital models (0.75±0.06, 0.89±0.11) (t=-9.31, P<0.001; t=-6.58, P<0.001). Conclusions: There is a difference between 2D and 3D measurement results of teeth in the esthetic area and the magnitude of the difference varies with their position in the dental arch. When analyzing the measurement of the anterior teeth, it is necessary to choose the appropriate method according to the target tooth position.

Maxillary Canine Impaction: Assessing the Influence of Maxillary Anatomy Using Cone Beam Computed Tomography.

BACKGROUND The purpose of this study was to evaluate the anatomical characteristics of patients with unilateral impacted canine teeth compared to a control group. Cone beam computed tomography (CBCT) records were retrospectively analyzed. MATERIAL AND METHODS CBCT records of 64 patients with unilateral impacted canine teeth (57.8% female and 42.2% male) and 64 controls (59.4% female and 40.6% male) were retrospectively analyzed. On the CBCT images, intermolar width, arch length, arch perimeter, palatal width in the molar region at cementoenamel junction, palatal width in the molar region at the crest, palatal width in the molar region measured from mid-root level, nasal cavity width, and palatal depth were evaluated. RESULTS In the palatal width measurement from the mid-root variable, the measurement of labially positioned canines was significantly lower than the control group (P<0.05). In terms of intermolar width, the labial positioned impacted canines' values were lower than in the control group. There was a significant difference in terms of the perimeter variable and both palatinally and labially positioned impacted canines were significantly lower than in the control group (P<0.05). All parameters were compared according to sex, and measurements of male patients were significantly higher than in female patients (P<0.05). CONCLUSIONS A labially impacted canine was strongly linked to a decrease in mid-root palatal and intermolar widths. Additionally, impacted canines positioned both palatally and labially were found to result in a reduced arch perimeter. Moreover, male patients with impacted canines exhibited notably greater anatomical measurements compared to female patients.

Variations in the Root Form and Root Canal Morphology of Permanent Mandibular canine.

BACKGROUND: Mandibular canines are recognized as usually having one root and one root canal in most cases. However, many investigators have reported the anatomical variations associated with mandibular canines. Thus; the objective of this study is to determine the number of roots and morphology of the root canal system of permanent mandibular canine in a Nepalese population. METHODS: Cone Beam Computerized Tomography images of 390 patients in a Nepalese population were selected, and a total of 780 mandibular canines were analyzed. The number of root and the canal configurations were investigated. Data were analyzed with descriptive analysis and Chi-square tests using the Statistical Package for the Social Sciences (SPSS) software version 20 (SPSS Inc, Chicago, IL, USA). RESULTS: Out of the 780 mandibular canines, 741(95%) were single-rooted canines while only 39 (5%) were double-rooted canines. The most common type of Vertucci in single-rooted canines was Type I (1-1) in the percentage of 85.6% and the least type was Type IV (1-2) in the percentage of (2.5%). The Chi-square tests showed no significant association between gender and number of roots (P = 0.87) and gender and root canal configuration in single-rooted canine (P = 0.52). CONCLUSIONS: All mandibular permanent canines were single rooted but 5.2% of the permanent mandibular canines had two roots.