Inclination Of Upper Incisors Research Articles

Automated diagnostic classification with lateral cephalograms based on deep learning network model

Objective: To establish a comprehensive diagnostic classification model of lateral cephalograms based on artificial intelligence (AI) to provide reference for orthodontic diagnosis. Methods: A total of 2 894 lateral cephalograms were collected in Department of Orthodontics, Capital Medical University School of Stomatology from January 2015 to December 2021 to construct a data set, including 1 351 males and 1 543 females with a mean age of (26.4± 7.4) years. Firstly, 2 orthodontists (with 5 and 8 years of orthodontic experience, respectively) performed manual annotation and calculated measurement for primary classification, and then 2 senior orthodontists (with more than 20 years of orthodontic experience) verified the 8 diagnostic classifications including skeletal and dental indices. The data were randomly divided into training, validation, and test sets in the ratio of 7∶2∶1. The open source DenseNet121 was used to construct the model. The performance of the model was evaluated by classification accuracy, precision rate, sensitivity, specificity and area under the curve (AUC). Visualization of model regions of interest through class activation heatmaps. Results: The automatic classification model of lateral cephalograms was successfully established. It took 0.012 s on average to make 8 diagnoses on a lateral cephalogram. The accuracy of 5 classifications was 80%-90%, including sagittal and vertical skeletal facial pattern, mandibular growth, inclination of upper incisors, and protrusion of lower incisors. The acuracy rate of 3 classifications was 70%-80%, including maxillary growth, inclination of lower incisors and protrusion of upper incisors. The average AUC of each classification was ≥0.90. The class activation heat map of successfully classified lateral cephalograms showed that the AI model activation regions were distributed in the relevant structural regions. Conclusions: In this study, an automatic classification model for lateral cephalograms was established based on the DenseNet121 to achieve rapid classification of eight commonly used clinical diagnostic items.

Difference in the alveolar bone remodeling between the adolescents and adults during upper incisor retraction: a retrospective study

The purpose of this study was to compare the difference of alveolar bone remodeling between the adolescents and adults in the maxillary incisor area during retraction. This retrospective study included 72 female patients who needed moderate anchorage to correct the bimaxillary protrusion. Subjects were further divided into the minor group (n = 36, 11–16 years old) and adult group (n = 36, 18–35 years old). Digital lateral cephalography and cone beam CT scanning were taken in each patient before (T0) and after treatment (T1). Cephalometry was conducted to assess incisor retraction, while alveolar bone thickness (ABT), alveolar bone distance (ABD), and alveolar bone area (ABA) were detected to assess changes in the alveolar bone. No difference in the inclination of upper incisors was observed at both T0 and T1 between two groups. Changes in the alveolar bone showed a similar tendency with bone apposition on the labial side and bone resorption on the palatal side in both groups. Less increase in the labial ABT (T1–T0) and more decrease in the palatal ABT (T1–T0) was found in the adult group, leading to less total ABT in the adult group. Higher reduction in ABD (T1–T0) was found in the adult group. Moreover, more decrease in the ABA (T1–T0) was found in the adult group. Adult patients have less alveolar bone support after treatment when compared with young adolescents. Orthodontists should take the age into consideration to reduce the potential periodontal risks during the treatment planning.

The Relation among Teeth and Maxillary Dental Arch Dimensions with Anterior Teeth Angulation and Inclination.

Objectives This study aimed at finding out whether anterior teeth angulation and inclination have a relationship with the maxillary teeth and dental arch dimensions. Methods Fifty study models with normal occlusion were selected from the archive of the Department of Orthodontics at Baghdad Dental Faculty. Maxillary dental arch width and length at different points were determined in addition to measuring anterior teeth angulation, inclination, crown thickness, overjet, overbite, and Bolton's ratios. The unpaired t-test and Pearson's correlation coefficient test were used for data analysis. Results No statistical gender differences were reported in all measurements except the dental arch widths and length where males had significantly higher mean values. Only the maxillary incisor's inclination showed a direct weak significant correlation with the total arch length. Conclusions The inclination of upper incisors had a minimal effect on increasing dental arch length.

Displacement in root apex and changes in incisor inclination affect alveolar bone remodeling in adult bimaxillary protrusion patients: a retrospective study

BackgroundPeriodontal health is of great concern for periodontists and orthodontists in the inter-disciplinary management of patients with bimaxillary protrusion. The aim of present study is to investigate changes in the alveolar bone in the maxillary incisor region and to explore its relationship with displacement of root apex as well as changes in the inclination of maxillary incisors during incisor retraction.MethodsSamples in this retrospective study consisted of 38 patients with bimaxillary protrusion. Cone-beam computed tomography (CBCT) images was taken before(T0) and after (T1) treatment. Alveolar bone thickness (ABT), height (ABH) and area (ABA) were utilized to evaluate changes in the alveolar bone, while incisor inclination and apex displacement were used to assess changes in the position of maxillary central and lateral incisors. Correlations between alveolar bone remodeling and apex displacement as well as changes in the inclination were investigated.ResultsThe labial ABT of central and lateral incisors at the mid-root third was increased. In contrast, the palatal ABT at crestal, mid-root and apical third level were consistently decreased. ABH was not altered on the labial side, while significantly decreased on the palatal side. ABA was not significantly increased on the labial side, but significantly decreased on the palatal side, leading to a significantly reduced total ABA. Orthodontic treatment significantly reduced inclination of upper incisors. Changes in the amount (T1-T0) of ABA was remarkably correlated with apex displacement and changes of inclination (T1-T0); in addition, using the multivariate linear regression analysis, changes of ABA on the palatal side (T1-T0) can be described by following equation: Changes of palatal ABA (T1-T0) = − 3.258- 0.139× changes of inclination (T1-T0) + 2.533 × apex displacement (T1-T0).ConclusionsRetraction of incisors in bimaxillary protrusion patients may compromise periodontal bone support on the palatal side. An equation that incorporated the displacement of root apex and change in the incisor inclination may enable periodontist-orthodontist interdisciplinary coordination in assessing treatment risks and developing an individualized treatment plan for adult patients with bimaxillary protrusion. Moreover, the equation in predicating area of alveolar bone may reduce the risks of placing the teeth out of the bone boundary during 3D digital setups.

Impact of force magnitude on effectiveness in cervical headgear therapy: a cephalometric analysis.

The main aim of this study was to study the impact of different force magnitudes on effectiveness in cervical headgear (CHG) therapy. Forty patients were treated with CHG with light (L; 300 g) or heavy (H; 500 g) force in this controlled clinical trial. Patients were asked to wear CHG for 10 hours/day for 10 months. The inner bow of the CHG was expanded (3-4 mm) and the long outer bow bent (10-20 degree) upward in relation to the inner bow. Adherence to instructions and force magnitude in CHG use was monitored by electronic module (Smartgear, Swissorthodontics, Switzerland). Lateral cephalograms were taken before (T1) and after (T2) the treatment and studied with modified Pancherz analysis using a Planmeca Romexis Ceph module (Planmeca, Finland). In both groups, skeletal and dental effects were seen. The only statistically significant difference in cephalometric analysis was the inclination of upper incisors at T1 (P = 0.010) and at T2 (P = 0.011). In both groups, a reduction in Sella-Nasion- point A (SNA) angle was found: L group T1 82.7degree (SD ± 3.6degree), T2 82.0degree (SD ± 3.5 degree) and H group T1 82.6 degree (SD ± 4.7 degree), T2 81.5 degree (SD ± 4.5 degree), but no statistically significant difference between the groups. Children in the L group used CHG statistically significantly more than those in the H group (10.0 ± 1.5 hour, and 8.3 ± 2.1 hour, respectively, P = 0.002). Children with lower force CHG seem to adhere better to instructions for CHG use. After 10 months of use, no statistically significant differences were found in dental or skeletal outcome. However, in the H group, the outcome was achieved with less daily hours of use.

Characteristics of maxillofacial morphology of Angle Class II patients with temporomandibular disorders involving crepitus

PurposeTo clarify the characteristics of maxillofacial morphology of Angle Class II orthodontic patients with temporomandibular disorders (TMD) involving crepitus suggesting osseous changes in the condyle, compared to Class II patients without TMD. Materials and methodsTwenty-four Japanese females accompanied by Angle Class II malocclusion with crepitus and 24 females accompanied by Class II malocclusion without TMD were examined. Pretreatment panoramic radiographs were used to measure condylar ratio (condylar height/ramus height). Pretreatment lateral cephalograms were used to analyze skeletal and dental morphology. Angular and linear measurements were compared between groups. Multiple linear regression analysis was used to identify associations of overjet with other cephalometric measurement values in both groups. ResultsClass II patients with crepitus showed significantly smaller condylar ratio as compared to Class II patients without TMD. Class II patients with crepitus exhibited significantly greater clockwise rotation of the mandible, shorter ramus height, more retruded mandible, less labially inclined upper incisors, and smaller overjet. Overjet of Class II patients with crepitus was significantly associated with inclination of upper incisors and ramus height, whereas that of patients without TMD was significantly associated with inclination of both upper and lower incisors and sagittal intermaxillary relationship. ConclusionSignificant smaller condylar ratio of Class II patients with crepitus suggested osseous changes in the condyle. Significant differences existed between morphological maxillofacial characteristics of Class II patients with and without crepitus. Overjet in Class II patients with crepitus correlated significantly with ramus height, attributed to resorbed deterioration and dysfunctional remodeling of the condyle.

Comparative Study of the Bionator and Multi. P Appliances in the Treatment of Class II Malocclusion: a Cephalometric Study

Background: Functional appliances such as Bionator have been used to treat Class II malocclusion. The purpose of this study was to compare the skeletal, dental and soft tissue effects of Bionator appliances with Multi-P (a newly developed appliance) in the treatment of Class II malocclusion.
 Subjects and methods: 45 class II children were chosen and randomly assigned to either the Bionator or Multi-P treatment group. After excluding 13 patients from the study, 21 patients in Bionator and 11 patients in Multi-P group have participated in the study. Lateral cephalograms were analyzed at the beginning (To) and at the end of treatment (T1) to evaluate the changes in both groups. The paired t.test and Leven’s test were enrolled for statistical analysis.
 Results: Reduction of ANB angle was detected in both treatment groups. The Bionator group underwent insignificant greater mandibular advancement as measured by the SNB angle. (p= 0.737) The mandibular plane angle increased insignificantly in both groups. (p> 0.05) The inclination of upper incisors decreased significantly in Multi-P group. (p= 0.042)
 Conclusion: Both appliances are effective therapeutic means for class II treatment associated with mandibular deficiency and may lead to normalization of the dentoskeletal parameters at the end of the treatment.

A influência da perda bilateral do primeiro molar inferior permanente na morfologia dentofacial: um estudo cefalométrico

OBJETIVO: avaliar as alterações cefalométricas em pacientes com perda bilateral do primeiro molar inferior permanente. MÉTODOS: foram analisadas 68 telerradiografias laterais de pacientes de consultórios particulares. A amostra foi dividida em dois grupos pareados quanto ao sexo e idade - 34 indivíduos sem perdas (grupo controle) e 34 com perda bilateral do primeiro molar inferior permanente (grupo com perda). Foram excluídos da amostra pacientes que haviam perdido outros dentes que não o primeiro molar inferior, casos de agenesia e pacientes com menos de 16 anos de idade. Buscou-se avaliar somente indivíduos que tivessem relatado a perda há pelo menos 5 anos. RESULTADOS: demonstraram que a perda bilateral do primeiro molar inferior permanente leva ao suave fechamento do ângulo GnSN (P=0,05), um giro anti-horário do plano oclusal (P=0,0001), uma suave diminuição da altura facial anteroinferior (P=0,05), uma acentuada inclinação lingual (P=0,04) e retrusão dos incisivos inferiores (P=0,03). Por outro lado, a perda bilateral do primeiro molar inferior permanente não foi capaz de influenciar a relação maxilomandibular no sentido anteroposterior (P=0,21), a quantidade de mento (P=0,45), a inclinação dos incisivos superiores (P=0,12) e a posição anteroposterior dos incisivos superiores (P=0,46). CONCLUSÃO: a perda bilateral dos primeiros molares inferiores é capaz de produzir alterações marcantes no posicionamento dos incisivos inferiores e no plano oclusal, além de uma suave redução vertical da face

Incisor Inclination – Risk Factor for Palatally-impacted Canines

The purpose of this study was to evaluate the torque of upper incisors and the maxillary size in sagittal direction in patients with impacted canines. Panoramic radiographs, cephalograms and pretreatment study models were evaluated in 199 patients (12.7 +/- 3.6 years) with impacted canines. The prevalence of malocclusions, inclination of the canine to the occlusal plane, incisors' inclination and maxillary size were determined. 45% of the patients showed symptoms of Class II, Division 2 malocclusion: at 18.5 degrees, the inclination of upper incisors (angle U1/NA) was lower and at 81.3 degrees the SNA angle higher than in patients with neutral conditions. There is no guidance for the erupting canine through the labial root torque of the upper incisors like in patients with missing lateral incisors. Patients with symptoms of Class II, Division 2 malocclusion should be regarded as a risk group for canine impaction.

Lower second molar extraction in correction of severe skeletal class III malocclusion.

The purpose of this study was to evaluate dentoskeletal and soft-tissue profile changes after extraction of lower second molars and treatment using the Tip-Edge technique in severe Class III subjects. Thirteen patients with severe skeletal Class III malocclusion (four males, nine females), diagnosed as requiring orthognathic surgery, but who rejected surgical therapy, were included in the study. The average age was 13.2 +/- 0.8 years. Lateral cephalometric films taken at the beginning and the end of treatment were analyzed using the Pancherz analysis and a traditional cephalometric analysis. The arithmetic mean and standard deviation were calculated for each variable. Paired t-test was performed to evaluate significant treatment change. After active treatment, dramatic overjet change was noted, with an average value of 5.5 mm (P < .001). Inclination of lower incisors was decreased 12.0 degrees when measured to the mandibular plane (P < .001). Inclination of upper incisors was increased by 2.1 degrees to the SN plane (P > .05). A negative value of the distance between upper and lower lip position to Sn-Pg' at the beginning of treatment changed to a positive value (P < .001). The results of this preliminary study suggest that success in the treatment of some severe Class III deformity in the permanent dentition can be achieved with fixed appliances and extraction of lower second molars. A remarkable soft-tissue change was noted after the treatment, and concave facial profiles changed to straight profiles.

Preliminary study of non-surgical treatment of severe Class III malocclusion in 18 patients of 12-20 years old

To analyze effects of non-surgical treatment on subjects of 12-20 years old with severe skeletal Class III deformity and to directly evaluate dental and facial profile changes. Eighteen patients with severe skeletal Class III malocclusion (male 5, female 13), diagnosed as indication for orthognathic surgery, were included in the study. The average age was 14.6 +/- 2.5 years old., with age range from 12 years old to 20 years old. 12 cases were treated with Tip-Edge straight-wire technique and 6 cases with Begg light wire technique. The average treatment time was 2.5 +/- 0.8 years. The selection criteria included: (1) mesial or superior mesial Class III molar relationship, with maxillary first molar occlude the buccal groove of the mandibular second molars (2) no mandibular shift (3) ANB < -1.5 degrees (4) high angle cases with average value of SN-MP 34.9 degrees +/- 5.9 degrees, 4 cases present with openbite (5) concave facial profile (6) originally classified as surgery cases. Lateral cephalometric films taken at the beginning and the end of the treatment were analyzed with traditional cephalometric analysis. The arithmetic mean (Mean) and standard deviation (SD) were calculated for each variable. Paired t-test was performed to evaluate the significant treatment change. Normal overjet and overbite were established with proclination of upper incisors and retroclination of lower incisors. Inclination of upper incisors was increased 5.9 degrees when measured with the angle of upper incisor to SN plane (P < 0.01). Inclination of lower incisors was decreased 6.6 degrees when measured with the angle of lower incisor to mandibular plane (P < 0.001). Negative value of the distance difference of upper lip and lower lip to Sn-Pg' at the beginning of treatment changed to positive value with significant difference (P < 0.001). Successful treatment effects could be obtained with non-surgical therapy in severe skeletal Class III malocclusion in permanent dentition. Remarkable soft-tissue change was noted after the treatment and concave facial profile changed to straight profile.

Relationship between the lingual-palatal contact duration associated with swallowing and maxillofacial morphology with the use of electropalatography

To investigate the relationship between movement of the tongue during swallowing and malocclusion, the relationship between the lingual-palatal contact duration associated with swallowing and maxillofacial morphology was examined by electropalatography, cephalometric radiography, and dental casts. Seventy-one subjects (35 men and 36 women, 18 to 38 years of age) with normal occlusion or various types of malocclusion were used. Simple correlation analysis showed correlations between the time required for swallowing and the angles—FH-U1, L6-MP, FH-MP and Go—measured by lateral cephalometric radiography. In multiple regression analysis, five angles—FH-U1, L6-MP, FH-Occ, FH-SGna and NF-MP—measured by lateral cephalometric radiography were chosen as the independent variables, and significant regression equations and multiple correlation coefficient were obtained. It was concluded that the lingual-palatal contact duration associated with swallowing observed by electropalatography differs among persons; this is closely related to the maxillofacial morphology and significantly correlated with the measurement items representing the rotation of the lower jaw and inclination of upper incisors. (Am J Orthod Dentofacial Orthop 1999;116:146-51)