Automatic determination of pubertal growth spurts based on the cervical vertebral maturation staging using deep convolutional neural networks.

BACKGROUND: This study aimed to develop a deep convolutional neural network (CNN) for automatic classification of pubertal growth spurts using cervical vertebral maturation (CVM) staging based on the lateral cephalograms of an Iranian subpopulation. MATERIAL AND METHODS: Cephalometric radiographs were collected from 1846 eligible patients (aged 5-18 years) referred to the orthodontic department of Hamadan University of Medical Sciences. These images were labeled by two experienced orthodontists. Two scenarios, including two- and three-class (pubertal growth spurts using CVM), were considered as the output for the classification task. The cropped image of the second to fourth cervical vertebrae was used as input to the network. After the preprocessing, the augmentation step, and hyperparameter tuning, the networks were trained with initial random weighting and transfer learning. Finally, the best architecture among the different architectures was determined based on the accuracy and F-score criteria. RESULTS: The CNN based on the ConvNeXtBase-296 architecture had the highest accuracy for automatically assessing pubertal growth spurts based on CVM staging in both three-class (82% accuracy) and two-class (93% accuracy) scenarios. Given the limited amount of data available for training the target networks for most of the architectures in use, transfer learning improves predictive performance. CONCLUSIONS: The results of this study confirm the potential of CNNs as an auxiliary diagnostic tool for intelligent assessment of skeletal maturation staging with high accuracy even with a relatively small number of images. Considering the development of orthodontic science toward digitalization, the development of such intelligent decision systems is proposed.

Evaluation of Nano TiO2 Modified Orthodontic Composite Effects on S. mutans Population and Enamel Demineralization in Fixed Orthodontic Patients; a Split Mouth Randomized Controlled Clinical Trial.

The high incidence of demineralization around orthodontic brackets has led to the development of preventive measures. Incorporation of antibacterial or remineralizing agents into orthodontic adhesives is an attractive method. This single-center, split-mouth, randomized controlled clinical trial was conducted to assess the effect of a modified composite containing TiO2 nanoparticles on the Streptococcus mutans population and to prevent demineralization around orthodontic brackets. Each participant was assigned a random sequence (AB or BA). During the bonding session, the control lateral incisor was bonded with a conventional composite and the contralateral incisor was bonded with a composite containing nano TiO2 particles (1%weight). The eligibility criteria included the presence of S. mutans in the dental plaque and absence of active caries, fractures or cracks. The S. mutans count in the dental plaque immediately around the brackets was evaluated at baseline and 1, 3, and 6 months after bonding. The specificity of the colonies was determined by PCR. The DIAGNOdent score was assessed at baseline and re-assessed every month up to the sixth month. Salivary samples were collected at T0, T1, and T3 to assess the amount of Ti released from the composite. The cytotoxicity of the modified composites was evaluated using an MTT assay. Participants, examiners, and data analyzers were blinded to the test and intervention groups. Forty-two patients ranging from 12 to 25 years were enrolled in this study. The amount of Ti released into saliva was insignificant and far below the toxic level. There was no significant difference between the S. mutans counts of the studied tooth S. mutans counts at any time point evaluated. DIAGNOdent scores on both sides increased significantly after the first month. However, this increase was higher on the test side (p < 0.001), and a significant difference of 2.6 scores remained throughout the study period. No severe adverse events were observed. Orthodontic composites containing TiO2 nanoparticles may prevent demineralization induced around brackets during orthodontic treatment. However, the antibacterial effects were not statistically significant.Registration: The protocol was registered with the IRCT.ir (IRCT20140215016582N6).

Sex determination from lateral cephalometric radiographs using an automated deep learning convolutional neural network.

Purpose: Despite the proliferation of numerous morphometric and anthropometric methods for sex identification based on linear, angular, and regional measurements of various parts of the body, these methods are subject to error due to the observer's knowledge and expertise. This study aimed to explore the possibility of automated sex determination using convolutional neural networks (CNNs) based on lateral cephalometric radiographs. Materials and Methods: Lateral cephalometric radiographs of 1,476 Iranian subjects (794 women and 682 men) from 18 to 49 years of age were included. Lateral cephalometric radiographs were considered as a network input and output layer including 2 classes (male and female). Eighty percent of the data was used as a training set and the rest as a test set. Hyperparameter tuning of each network was done after preprocessing and data augmentation steps. The predictive performance of different architectures (DenseNet, ResNet, and VGG) was evaluated based on their accuracy in test sets. Results: The CNN based on the DenseNet121 architecture, with an overall accuracy of 90%, had the best predictive power in sex determination. The prediction accuracy of this model was almost equal for men and women. Furthermore, with all architectures, the use of transfer learning improved predictive performance. Conclusion: The results confirmed that a CNN could predict a person's sex with high accuracy. This prediction was independent of human bias because feature extraction was done automatically. However, for more accurate sex determination on a wider scale, further studies with larger sample sizes are desirable.

DIAGNOdent pen quantification of the synergy of NovaMin® in fluoride toothpaste to remineralize white spot lesions in patients with fixed orthodontic appliances: A double-blind, randomized, controlled clinical trial.

OBJECTIVES: White spot lesions (WSLs) are a real problem in patients with fixed orthodontic appliances with inadequate hygiene and eating habits. This study aimed at evaluating the synergic effects of NovaMin in fluoride toothpaste on remineralization of WSLs in patients with fixed orthodontic appliances. METHODS: In the present double-blind, randomized, controlled, parallel, clinical trial, Patients with a minimum of 1 WSL on the buccal surface of the anterior teeth and the first premolar on both arches were recruited between 12 February 2021 and 12 April 2021 at the Faculty of Dentistry of X. They were randomly divided into 2 groups, the control group receiving fluoride toothpaste (Sensodyne® Rapid Relief, England), and the study group receiving the fluoride-containing toothpaste and NovaMin (Sensodyne® Repair and Protect, England). A DIAGNOdent pen (KAVO Dental Corporation, Germany) was used to score the WSLs at baseline and then after the usage for 1 and 3months. The primary outcome measures were the difference in DIAGNOdent score in patients with fixed orthodontic appliances that used fluoride toothpaste and NovaMin/fluoride toothpaste. The secondary outcome measures were the intragroup comparison of the DIAGNOdent score in patients with fixed orthodontic appliances that used fluoride toothpaste and NovaMin/fluoride toothpaste. The type of toothpaste used was blinded for the participants, examiner, and data analyser. RESULTS: A sample size comprising 38 patients (19 patients in each group) was determined. In each group, statistical analysis was conducted on 18 patients. A patient in each group refused to contribute to the study. In both groups (P<0.001), the DIAGNOdent reading of the WSLs decreased significantly after 1 and at 3months, though no significant difference was found between the two groups at different intervals. Each patient had no adverse effects. CONCLUSIONS: In this 3-month follow-up study, NovaMin/fluoride toothpaste provided a slight improvement in WSL remineralisation, but not significant compared to fluoride toothpaste. NovaMin therefore did not have a significant synergistic effect. Both types of toothpaste can improve WSLs in orthodontic patients. THE CLINICAL TRIAL REGISTRATION NUMBER: IRCT20140215016582N5.

Anatomical characteristics of mandibular bone in skeletal class I, II and III patients by using cone beam computed tomography images in an iranian population / Características anatômicas do osso mandibular em pacientes Classe I, II e III esquelética usando imagens de Tomografia Computadorizada de Feixe Cônico: em uma População Iraniana

Objetive: This study aimed to compare the anatomical characteristics of the mandible in patients with skeletal class I, II and class III disorders using cone beam computed tomography (CBCT). Material and Methods: CBCT scans of patients between 17 to 40 years taken with NewTom 3G CBCT system with 12-inch field of view (FOV) were selected from the archive. Lateral cephalograms were obtained from CBCT scans of patients, and type of skeletal malocclusion was determined (Class I, II or III). All CBCT scans were evaluated in the sagittal, coronal and axial planes using the N.N.T viewer software. Results: The ramus height and distance from the mandibular foramen to the sigmoid notch in class II patients were significantly different from those in skeletal class I (P < 0.005). Distance from the mandibular canal to the anterior border of ramus in class III individuals was significantly different from that in skeletal class I individuals (P < .005). Conclusion: Length of the body of mandible in skeletal class I was significantly different from that in skeletal class II and III patients. Also, ramus height in skeletal class I was significantly different from that in skeletal class II patients. CBCT had high efficacy for accurate identification of anatomical landmarks. (AU)

Objetivo: Este estudo teve como objetivo comparar as características anatômicas da mandíbula em pacientes com desordem esquelética Classe I, II e III usando imagens de tomografia computadorizada de feixe cônico (TCFC). Material e Métodos: Foram selecionadas de arquivo, imagens de TCFC (Sistema NewTon 3G) com FOV (campo de visão) 12 polegadas e incluindo pacientes entre 17 a 40 anos. Cefalometrias laterais foram obtidas a partir das imagens de TCFC e o tipo de maloclusão esquelética foi determinada (Classe I, II ou III). Todas as imagens de TCFC foram avaliadas nos planos sagital, coronal e axial usando o software de visualização N.N.T. Resultados: A altura do ramo e distância do forame mandibular para a incisura da mandíbula em pacientes Classe II foi significativamente diferente daqueles Classe I esquelética (p< 0.005). A distância do canal mandibular até a borda anterior do ramo em indivíduos Classe III foi significativamente diferente daqueles indivíduos Classe I esquelética (p<0.005). Conclusão: O comprimento do corpo da mandíbula na Classe I esquelética foi diferente significativamente daqueles pacientes em Classe II e III esquelética. Além disso, a altura do ramo na Classe I esquelética foi significativamente diferente daqueles pacientes Classe II esquelética. A TCFC apresentou alta eficácia para a identificação precisa de marcos anatômicos. (AU)

Effects of TiO2-Coated Stainless Steel Orthodontic Wires on Streptococcus mutans Bacteria: A Clinical Study.

INTRODUCTION: The aim of this study was to clinically evaluate Streptococcus mutans adhesion on titanium dioxide-coated stainless steel orthodontic wires to decrease white-spot formation. METHODS: In this study, four groups of 17 patients each (n=68) aged 12-25 years participated. A titanium dioxide coating layer was deposited on 0.4572 mm stainless steel orthodontic wires using physical vapor deposition. The coated wires were randomly assigned to one jaw, and the opposite jaw received an uncoated wire as control. Patients were divided into groups according to the duration that wires were in their mouths: A) 1 week, B) 2 weeks, C) 3 weeks, and D) 4 weeks. Block randomization was used to assign patients to each group. At the end of the experiment, 20 mm of each wire (canine-to-canine area) was cut and cultured in S. mutans-specific medium. The culture plates were placed in an incubator containing 5% CO2 for 72 hours at 37°C, and then colonies were counted. MTT was used to test the biocompatibility of the coated and uncoated wires. To evaluate the stability of the coated titanium dioxide layer on the wires, titanium concentration on the saliva was determined using inductively coupled plasma mass spectroscopy. RESULTS: The Kruskal-Wallis test showed that there was no significant difference in colony counts among the coated wires during 1-4 weeks (p<0.48). In the uncoated-wire groups, colonys count at week 1 were higher than weeks 24 -(p<0.022). Wilcoxon's test showed that the number of colonies was significantly different in groups A and C, but there was no significant difference in groups B or D. MTT-assay results showed that there was not a significant difference between cell viability in the coated-wire group and the control. The Kruskal-Wallis test showed that there was no significant difference in titanium concentration in the studied groups (p<0.834). CONCLUSION: Application of titanium dioxide coating is effective in reducing bacterial adhesion at wire insertion.

Extraction versus non-extraction orthodontic treatment: Soft tissue profile changes in borderline class I patients.

BACKGROUND: The decision regarding the selection of extraction or non-extraction orthodontic treatment is a common challenge in orthodontic treatment planning. OBJECTIVES: The objective of this study was to compare the effects of extraction and non-extraction orthodontic treatment on the soft tissue profile of borderline class I patients. MATERIAL AND METHODS: In this retrospective study, 70 patients were selected from among those referred to the Department of Orthodontics of the Faculty of Dentistry at Hamadan University of Medical Sciences in Iran. The inclusion criteria were skeletal class I, 4-10 mm of space deficiency, and the possibility of applying both extraction and non-extraction orthodontic treatment. All patients underwent fixed orthodontic treatment with the use of 0.022-inch-slot edgewise brackets. The patients were divided into 2 groups (n = 35) according to the 4-premolar extraction or non-extraction treatment plan. The 2 groups were compared by means of the cephalometric analysis. RESULTS: There were 11 males and 24 females at a mean age of 17.46 years in the non-extraction group, and 9 males and 26 females at a mean age of 18.46 years in the extraction group. The upper and lower incisors as well as the lower lip moved forward in the non-extraction group (lower lip to E­plane = 0.87 ±1.39 mm, U1-SN = 2.83 ±8.03°, IMPA = 4.64 ±5.47°). The incisors and the lips moved backward in the extraction group (upper lip to E­plane = -1.42 ±2.08 mm, lower lip to E­plane = -1.56 ±1.97 mm, U1-SN = -7.63 ±9.02°, IMPA = -7.05 ±6.79°). The differences were statistically significant (p < 0.05). Mentolabial sulcus became more pronounced in the non-extraction group (1.92 ±2.73 mm; p < 0.001) and shallower in the extraction group (-1.90 ±4.2 mm; p = 0.000). CONCLUSIONS: Orthodontic treatment can change the soft tissue appearance of the lower third of the face. The lips and the incisors moved forward in the non-extraction group and backward in the extraction group.

Position of the hyoid bone and its correlation with airway dimensions in different classes of skeletal malocclusion using cone-beam computed tomography.

PURPOSE: This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class II, and class III malocclusions. Eight linear and 2 angular hyoid parameters (H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean cross-sectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with P values <0.05 indicating statistical significance. RESULTS: The mean airway volume differed significantly among the malocclusion classes (P<0.05). The smallest and largest volumes were noted in class II (2107.8±844.7 mm3) and class III (2826.6±2505.3 mm3), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class II and III malocclusions and between H-Y and upper airway length in class I malocclusions. CONCLUSION: The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.

The study of facial morphology in patients with vertical growth pattern (hyperdivergent) lacking or showing temporomandibular disorders symptoms.

AIM: According to the large number of studies, there seems to be a significant relation between hyperdivergence growth pattern and temporomandibular disorders. However, it is not clearly scrutinized which morphological factors can contribute to the development of temporomandibular disorders. The aim of this study was to investigate the relation between some skeletal and facial morphologic features of hyperdivergent facial growth pattern patients and temporomandibular disorders. MATERIALS AND METHODS: This case-control study was performed on a population of 50 patients including 25 patients with temporomandibular disorder and 25 non- temporomandibular disorder individuals aged between 15-30 years with hyperdivergent growth pattern (Frankfurt Mandibualr plane angle between 28 and 35 degree). Two groups of symptomatic and asymptomatic patients (case and control) were matched for age and gender. In order to evaluate the skeletal and dental variables, lateral cephalometries was taken and traced after obtaining written consent from the patients. The measured variables were A point to Nasion to B point, Frankfurt plane to Nasion to Pogonion, Nasion to A point to Pogonion, Sella to Gnathion to Frankfurt plan, Articular point to Gonion-Menton, Sella to Articular point to Gonion, Palatal plane to Mandibular plane, and Articular point to Gonion angles. The intervals of Basion to Nasion, Sella to Basion, Gonion to Menton, and amounts of Anterior facial height meas, Upper Anterior facial height ratio to Lower Anterior facial height, posterior facial height, overjet, and overbite Data were analyzed by Chi2 test, t-test, and multivariate test. RESULTS: According to the descriptive statistics, the age of the control and case groups averaged 21.12±1.99 and 21.63±1.58 years respectively. Among the people referred to the dental school, the frequency of males and females in the control and case groups were 6, 7 and 19, 18 respectively. The results of t-test and multivariate tests indicated significant differences between the two variables of overbite and mandibular length. CONCLUSION: The present study revealed increased overbite (dental feature) and mandibular length (skeletal feature) is more likely to be associated with a higher risk of temporomandibular disorders joint disease in patients with hyperdivergent facial growth pattern. CLINICAL SIGNIFICANCE: Treatment of the deep bite condition can be helpful in improving temporomandibular disorder.

The relation between dental age and cervical vertebral maturation in orthodontic patients aged 8 to 16 years: A cross-sectional study.

OBJECTIVE: This study aimed to assess the relation between the dental age of seven left mandibular teeth determined by the Demirjian's method and skeletal age determined by the Baccetti's method. MATERIALS AND METHODS: This cross-sectional study evaluated 600 patients aged between 8-16 years, who were selected from those presenting to Orthodontics Department of Hamadan dental school and private orthodontic offices. The patients had good-quality panoramic radiographs and lateral cephalograms taken within 2 months of each other. Skeletal age was determined according to the cervical vertebral maturation (CVM) on lateral cephalograms. The dental age of seven left mandibular teeth was determined using the Demirjian's method. Data were analysed by the Spearman's and Pearson's correlation coefficients via SPSS 16. RESULTS: CVM had significant correlations with dental age (0.780) and chronological age (0.792). Accordingly, the strongest correlation was noted between CVM and the developmental stage of second molars in both males and females. In males, the highest correlation between dental age and chronological age was in CS5 stage (0.724) while, in females, the highest correlation between dental age and chronological age was in CS4 stage (0.651). CONCLUSION: Considering the correlation between skeletal age and dental calcification, dental age, especially the developmental stage of mandibular second molars, based on panoramic radiographs, can be served as a primary diagnostic tool for determining the skeletal maturity stage of patients.

Comparison of Bolton ratio in normal occlusion and different malocclusion groups in Iranian population.

OBJECTIVES: Bolton ratio is used as a method for diagnosis of tooth size discrepancy. Tooth size discrepancy has an important role in the stability of results of final orthodontic treatment. The aim of this study was to determine and compare Bolton ratio in normal occlusion and different malocclusion groups of Iranian population. MATERIALS AND METHODS: This descriptive-analytic study comprises 240 orthodontic patient casts (for every malocclusion group: class I, class II division 1, class II division 2, class III, 30 males and 30 females) which have fully erupted and complete permanent dentitions from first molar to first molar, and also 60 persons (30 male-30 female) with normal occlusion. The mesiodistal tooth sizes were measured using digital caliper two times with a 4-week interval. RESULTS: The average mesiodistal size of all teeth in the malocclusion group was significantly bigger than in the normal occlusion group. Although there was no relationship between anterior ratio and gender or malocclusion groups, but a significant relationship between total ratio in Class II division 1 and normal occlusion was seen. Furthermore, a significant difference between anterior and total ratios in the present study and original Bolton's values was found. CONCLUSIONS: In the normal occlusion group, the anterior and total ratios were bigger than those in Bolton's original study. Also, "class II division 1" showed the lowest values of Bolton ratio among the other normal occlusion and malocclusion groups. Therefore, the original Bolton's values should be used conservatively in Iranian population.

Comparison of conventional and laser-aided fiberotomy in relapse tendency of rotated tooth: A randomized controlled clinical trial.

INTRODUCTION: The aim of the present study was to compare the tendency of mandibular incisor rotation relapse after conventional circumferential supracrestal fiberotomy (CSF) with Er,Cr:YSGG laser-aided CSF. METHODS: In this three-arm parallel study, the patients with one lower incisor rotation greater than 30 degrees before treatment were selected. The patients were randomly assigned to three groups in a 1:1:1 ratio. Rotational relapse tendency was measured on a digitized model one month after arch wire removal. Probing depth, clinical crown height and pain levels were also measured. RESULTS: A total of 46 patients were recruited. Relapse tendency in conventional CSF and laser-aided CSF groups were 5.09±1.59° and 4.87±2.08°, respectively, and significantly lower than 11.28±2.93° in the control group (P<0.001). Relapse tendency was not different between the conventional CSF and laser CSF groups. Probing depth, clinical crown height, and experienced pain levels exhibited negligible differences. CONCLUSIONS: Er,Cr:YSGG laser-aided CSF in one month was as effective in reducing rotational relapse tendency of mandibular incisor teeth as conventional CSF.

Effect of Erbium, Chromium-Doped: Yttrium, Scandium, Gallium, and Garnet and Erbium: Yttrium-Aluminum-Garnet Laser Etching on Enamel Demineralization and Shear Bond Strength of Orthodontic Brackets.

OBJECTIVE: The objective of this study was to compare the effect of two types of laser irradiation (erbium, chromium-doped: yttrium, scandium, gallium, and garnet [Er,Cr:YSGG] and erbium: yttrium-aluminum-garnet [Er:YAG]) and acid etching on enamel demineralization and shear bond strength (SBS) of orthodontic bracketsastry. MATERIALS AND METHODS: Ninety premolars were selected, scaled, and polished with no fluoridated pumice, and metal brackets were bonded to them. Then, they were randomly allocated to three groups based on the etching procedure: phosphoric acid etching, Er:YAG (100 mJ, 10 Hz) laser etching, and Er,Cr:YSGG (600 mJ, 20 Hz) laser etching. Teeth to be evaluated for demineralization and SBS were exposed to pH and thermal cycling, respectively. For SBS test, a universal testing machine was used, and adhesive remnant was index scored after debonding. Microhardness of enamel was evaluated with Vickers test. Data were analyzed statistically (α = 0.05). RESULTS: The acid-etched group exhibited significantly higher SBS values compared to the laser groups (P < 0.05); however, the difference between the Er:YAG and Er,Cr:YSGG laser groups was not significant. Microhardness mean values in descending order were as follows: Er,Cr:YSGG, Er:YAG, and acid etched. There were significant differences between the laser and control groups (P < 0.001); however, the difference between the two laser groups was not significant (P = 0.320). There were no significant differences between the three groups in adhesive remnant index scores. CONCLUSION: Er:YAG and Er,Cr:YSGG laser etching resulted in clinically acceptable SBS; therefore, apart from its other advantages over acid etching, it can be a good appropriate alternative for bonding of orthodontic brackets.

Comparison Efficiency of Posteroanterior Cephalometry and Cone-beam Computed Tomography in Detecting Craniofacial Asymmetry: A Systematic Review.

OBJECTIVES: The aim of this systematic review is to compare cone-beam computed tomography (CBCT) and two-dimensional radiography in the assessment of facial asymmetry. METHODS: Three valid electronic databases (PubMed, Scopus, and Web of Science) were searched for articles published from 1973 to February 2017. Hand searching was done through references of selected articles, internal thesis, and national and international conferences. The titles and abstracts obtained from the search were evaluated by reviewers according to the inclusion and exclusion criteria. RESULTS: The established search strategy identified 2137 articles. A total of 2079 articles were from electronic search in three international databases and 58 articles from hand searching. After eliminating duplicate articles and on the basis of inclusion and exclusion criteria, 13 articles and 1 thesis entered the final analysis. Bayesian meta-analysis was done due to the heterogeneity of articles and the differences related to the methodology of the studies. According to this method, analyzing J-J landmark in two studies showed that there were no statistical differences between posteroanterior (PA) radiography and three-dimensional method with reference standard. CONCLUSION: The results of the study showed that there was no preference between the two techniques in measuring and diagnosing the landmarks and evaluating asymmetry. It can be concluded that in patients having problems other than asymmetry and need more information for the treatment plan, CBCT is more helpful than PA cephalometry.

Smile attractiveness perception regarding buccal corridor size among different facial types.

BACKGROUND: The width of the buccal corridor (BC) is one of the factors affecting smile attractiveness. OBJECTIVES: The aim of this study was to determine the effects of the BC size on the smile attractiveness of individuals with short, normal and long faces from the viewpoint of laypersons, general dentists and orthodontists. MATERIAL AND METHODS: Smiling photographs of male and female subjects who met the inclusion criteria were digitally altered to create 3 BC sizes (narrow: 2%; normal: 15%; wide: 28%) and 3 facial types defined by the facial index (FI) (short face: FI ≤ 83.9; normal face: 84.0 ≤ FI ≤ 87.9; long face: FI ≥ 88.0). Nine different combinations were made and the evaluators rated the overall attractiveness and acceptability of each smile on a 10-millimeter visual analog scale (VAS). RESULTS: A total of 53 raters (22 laypersons, 16 general dentists and 15 orthodontists) participated in this study. The orthodontists and general dentists had similar viewpoints and they preferred narrow and normal BCs over the wide ones in all facial types. Laypersons preferred normal BC for normal faces, while they did not distinguish different BCs in short faces. CONCLUSIONS: Variations in the BC size affect smile attractiveness in different facial types and wide BCs are attributed to the least attractive smiles. Due to the different viewpoints of laypersons and professionals in this regard, there is no justification for expanding the maxillary arch to achieve more attractive smiles.

Treatment decision analysis for palatally-displaced canines based on orthodontists' opinion and CBCT.

OBJECTIVES: The aim of this study was to assess difficulty of treatment of palatally-displaced canines (PDC) according to experts' opinion using CBCT data and to determine a cut-off point for extraction versus forced eruption. SUBJECTS AND METHODS: Seven CBCT variables of thirty PDC cases were measured with Dolphin 3D software. In addition to measurements of each case, nine 3D and 2D views were prepared on one page and uploaded on the website (canineimpaction.com). Thirty-four orthodontists were asked to judge the difficulty of bringing the impacted canine into occlusal plane. Then, they scored from 1 to 5 the effect of each variable on treatment difficulty and also decided whether to force-erupt or extract the impacted tooth. RESULTS: Overlap in frontal view, angulation of the canine to the occlusal plan, vertical distance to the occlusal plane, age, dilaceration and rotation had significant relationship with the level of treatment difficulty. The treatment plan decision for PDC with treatment difficulty>7.5 was extraction rather than forced eruption. CONCLUSION: We can predict treatment difficulty of PDC by measuring CBCT variables and decide to extract or force-erupt with a reasonable level of agreement among a panel of orthodontists.

Web-based evaluation of experts' opinions on impacted maxillary canines forced eruption using CBCT.

AIM: This study aims at examining the difficulty in performing forced eruption of impacted maxillary canines, using CBCT information and according to experienced orthodontist's opinion. The second aim was to find the most important factors related to this decision. METHODS: Based on a careful literature review on impacted maxillary canines, ten main factors were selected to assess difficulties associated with impacted teeth. Thirty six consecutive patients with 50 impacted maxillary canines were examined and variables were measured for each impacted tooth using Dolphin 3D software. Ten orthodontists assessed the radiographs of teeth and provided their opinion on the difficulty in bringing impacted teeth into occlusion named subjective degree of difficulty (SDD). The correlation established between mean SDD of each tooth and measured variables were analyzed by means of linear regression. RESULTS: Mean SDD was 6.45 ± 1.22 for all 50 teeth. Linear regression showed a high coefficient of correlation between mean SDD and age, dilacerations, vertical height, angulation and horizontal overlap (P < 0.05). CONCLUSION: To predict the difficulty of impacted maxillary canines forced eruption, according to the opinion of experienced orthodontists, the factors age, dilaceration, angulation, overlap and vertical distance from the occlusal plane are the most important variables.

Web-based evaluation of experts' opinions on impacted maxillary canines forced eruption using CBCT

AIM: This study aims at examining the difficulty in performing forced eruption of impacted maxillary canines, using CBCT information and according to experienced orthodontist's opinion. The second aim was to find the most important factors related to this decision. METHODS: Based on a careful literature review on impacted maxillary canines, ten main factors were selected to assess difficulties associated with impacted teeth. Thirty six consecutive patients with 50 impacted maxillary canines were examined and variables were measured for each impacted tooth using Dolphin 3D software. Ten orthodontists assessed the radiographs of teeth and provided their opinion on the difficulty in bringing impacted teeth into occlusion named subjective degree of difficulty (SDD). The correlation established between mean SDD of each tooth and measured variables were analyzed by means of linear regression. RESULTS: Mean SDD was 6.45 ± 1.22 for all 50 teeth. Linear regression showed a high coefficient of correlation between mean SDD and age, dilacerations, vertical height, angulation and horizontal overlap (P < 0.05). CONCLUSION: To predict the difficulty of impacted maxillary canines forced eruption, according to the opinion of experienced orthodontists, the factors age, dilaceration, angulation, overlap and vertical distance from the occlusal plane are the most important variables. .

OBJETIVO: o presente estudo tem o objetivo de avaliar, de acordo com a opinião de ortodontistas experientes, a dificuldade de se realizar a erupção forçada de caninos superiores impactados, com base em informações fornecidas por tomografia computadorizada de feixe cônico. O objetivo específico foi identificar os fatores mais importantes relacionados a essa opção de tratamento. MÉTODOS: com base em uma revisão meticulosa da literatura sobre caninos superiores impactados, selecionamos os dez principais fatores utilizados para avaliar a dificuldade em tratar dentes impactados. Trinta e seis pacientes, com um total de 50 caninos superiores impactados, foram avaliados. As variáveis para cada dente impactado foram obtidas utilizando o programa Dolphin 3D. Dez ortodontistas avaliaram as radiografias referentes aos dentes selecionados e opinaram sobre a dificuldade em alinhar dentes impactados. O grau de dificuldade foi denominado Grau de Dificuldade Subjetivo (GDS). A relação entre o valor médio de GDS de cada dente e as variáveis obtidas foi analisada por regressão linear. RESULTADOS: o valor médio de GDS foi de 6,45 ± 1,22, para todos os dentes. A regressão linear gerou um alto coeficiente de relação entre o valor médio de GDS e as variáveis idade, dilaceração, altura vertical, angulação e sobreposição horizontal (p < 0,05). CONCLUSÃO: de acordo com a opinião de ortodontistas experientes, para prever a dificuldade em se realizar a erupção forçada de caninos superiores impactados, as variáveis idade, dilaceração, angulação, sobreposição e distância vertical do plano oclusal são as mais importantes. .