Accuracy of artificial intelligence-assisted growth prediction in skeletal Class I preadolescent patients using serial lateral cephalograms for a 2-year growth interval.

OBJECTIVE: To investigate the accuracy of artificial intelligence-assisted growth prediction using a convolutional neural network (CNN) algorithm and longitudinal lateral cephalograms (Lat-cephs). MATERIALS AND METHODS: A total of 198 Japanese preadolescent children, who had skeletal Class I malocclusion and whose Lat-cephs were available at age 8 years (T0) and 10 years (T1), were allocated into the training, validation, and test phases (n = 161, n = 17, n = 20). Orthodontists and the CNN model identified 28 hard-tissue landmarks (HTL) and 19 soft-tissue landmarks (STL). The mean prediction error values were defined as 'excellent,' 'very good,' 'good,' 'acceptable,' and 'unsatisfactory' (criteria: 0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm, respectively). The degree of accurate prediction percentage (APP) was defined as 'very high,' 'high,' 'medium,' and 'low' (criteria: 90%, 70%, and 50%, respectively) according to the percentage of subjects that showed the error range within 1.5 mm. RESULTS: All HTLs showed acceptable-to-excellent mean PE values, while the STLs Pog', Gn', and Me' showed unsatisfactory values, and the rest showed good-to-acceptable values. Regarding the degree of APP, HTLs Ba, ramus posterior, Pm, Pog, B-point, Me, and mandibular first molar root apex exhibited low APPs. The STLs labrale superius, lower embrasure, lower lip, point of lower profile, B', Pog,' Gn' and Me' also exhibited low APPs. The remainder of HTLs and STLs showed medium-to-very high APPs. CONCLUSION: Despite the possibility of using the CNN model to predict growth, further studies are needed to improve the prediction accuracy in HTLs and STLs of the chin area.

Three-dimensional evaluation of mandibular lingula: Comparisons of skeletal angle classifications and growth patterns.

OBJECTIVES: This study aimed to evaluate the position of the mandibular lingula (ML) in adult patients (aged between 18 and 35 years old) with different skeletal and growth patterns using cone-beam computed tomography (CBCT). DESIGN: Cross-sectional. SETTING: Dentistry department of University. SUBJECTS: Subjects comprised CBCT images of 150 adult patients, including 300 rami. METHODS AND MATERIALS: In total, 150 CBCT aged between 18 and 35 were selected and divided into three main groups of 50 samples based on their skeletal relationships (classes I, II and III). Patients were subdivided based on their growth pattern (vertical vs. horizontal), resulting in 25 samples per subgroup. Distances between the mandibular lingula and occlusal plane (ML-OP), sigmoid notch (ML-SN), external oblique ridge (ML-EOR), internal oblique ridge (ML-IOR), posterior border of the ramus (ML-PBR), inferior border of the ramus (ML-IBR), and horizontal and vertical distances to the mandibular foramen (ML-hMF and ML-vMF). One-way ANOVA variance analysis was employed to compare different angle classifications, and Bonferroni analysis was used for multiple comparisons. The Student's t-test was also used to compare growth patterns within each main group and genders within the subgroup. RESULTS: The study revealed statistically significant differences in the position of the mandibular lingula between different angle classifications, growth patterns, and genders. Class II samples showed a more anterior position of the ML, whereas Class III samples displayed a more posterior position of the ML. Patients with horizontal growth patterns and Angle Class III had a more posteriorly positioned ML. Gender differences were observed, particularly in Class I and Class III classifications, suggesting that gender may influence the variability of ML position in these specific classifications. CONCLUSION: The position of the mandibular lingula showed high variability among individuals with different angle classifications, growth patterns and genders.

Is hand-wrist radiography still necessary in orthodontic treatment planning?

OBJECTIVES: The aim of our study is to compare the relationship between hand-wrist and cervical vertebra maturation stages with chronological age and to investigate the effect of malocclusion type on the relationship between these methods. MATERIALS AND METHODS: Hand-wrist and cephalometric radiographs of 1000 patients (526 females, 474 males) with a mean age of 13.41 ± 1.83 were analyzed. The methods of Bacetti et al. were used for the cervical vertebra maturation stage, and Björk, Grave and Brown's methods were used for the hand-wrist maturation stage. One-way ANOVA test was applied to compare skeletal classes between them. Tukey post hoc test was used to determine the differences. The relationship between the malocclusion type, cervical vertebra and hand-wrist maturation stages was evaluated with the Spearman correlation test. RESULTS: Spearman's correlation coefficient was 0.831, 0.831 and 0.760 in Class I, II and III females, respectively. In males, it was calculated as 0.844, 0.889 and 0.906, respectively. When sex and malocclusion were not differentiated, the correlation was found to be 0.887. All were statistically significant (P < 0.001). The highest correlation was observed in class III males, while the lowest was found in class III females. CONCLUSION: Cervical vertebrae can be used safely to assess pubertal spurt without hand-wrist radiography. Diagnosing growth and development stages from cephalometric images is important in reducing additional workload and preventing radiation risk.

Morphometric analysis of tooth morphology among different malocclusion groups in a hispanic population.

BACKGROUND: There have been reports of unique dental morphological features amongst Latin American and Hispanic populations, and this might invalidate the use of current orthodontic diagnostic tools within this population. There are no tooth size/tooth ratio normative standards for the Hispanic population, despite overwhelming evidence about differences in tooth size between racial groups. OBJECTIVE: This study aimed to determine whether there are significant differences in 3-D tooth shape between patients with Angle Class I, Class II, and Class III dental malocclusion in the Hispanic population. METHODOLOGY: Orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III dental malocclusions scanned using an intra-oral scanner. The scanned models were digitized and transferred to a geometric morphometric system. Tooth size shape were determined, quantified, and visualized using contemporary geometric morphometric computational tools using MorphoJ software. General Procrustes Analysis (GPA) and canonical variates analysis (CVA) used to delineate the features of shape that are unique to each group. RESULT: The study revealed differences in tooth shape between the different dental malocclusion groups on all twenty-eight teeth that were studied; the pattern of shape differences varied between the teeth and the dental malocclusions. The MANOVA test criteria, F approximations, and P-values show that shape in all the groups was significantly different < 0.05. CONCLUSION: This study revealed differences in tooth shape between the different dental malocclusions on all teeth, and the pattern of shape differences varied between the different dental malocclusions group.

A preliminary study of buccal and lingual alveolar bone thickness of posterior teeth in patients with skeletal Class III malocclusion and mandibular asymmetry.

INTRODUCTION: The purposes of this retrospective study were to investigate the buccal and lingual alveolar bone thickness values of the posterior teeth in patients with asymmetrical skeletal Class III malocclusion and compare them with patients with symmetrical skeletal Class III and Class I malocclusion. METHODS: Seventy-eight cone-beam computed tomography scans were classified into 3 groups according to the sagittal pattern and menton deviation: asymmetrical Class III (n = 26), symmetrical Class III (n = 26), and symmetrical Class I (n = 26). The buccal and lingual alveolar bone thickness of the first molar and premolars in the maxilla and mandible were measured at 3, 6, and 8 mm apical to the cementoenamel junction and the apical and middle levels of the root. Measurements were compared among the 3 groups. RESULTS: In the asymmetrical Class III group, the buccal alveolar bone along the distobuccal root of the maxillary first molar on the deviated side was thinner by 1.07 to 1.10 mm than that in the symmetrical Class I group at 6-mm, 8-mm, and middle-level planes (P <0.001, P <0.01, and P <0.001). The buccal alveolar bone thickness along the distal and mesial roots of the mandibular first molar on the deviated side was thinner by 1.28 to 1.85 mm, and by 0.72 to 1.21 mm, respectively (P <0.001 and P <0.01), than that in the symmetrical Class I group at 6-mm, 8-mm, apical and middle-level planes. CONCLUSIONS: In this preliminary study, patients with skeletal Class III malocclusion showed thinner buccal and lingual alveolar bone in the posterior teeth than subjects with Class I malocclusion. Particular attention should be paid to buccal alveolar bone thickness along the distobuccal root of the maxillary and distal root of the mandibular first molar to prevent periodontal complications in decompensation. Future studies should involve larger sample sizes, more repeatable and comprehensive measuring and statistical methods.

Potentialities and limitations of computer-aided design and manufacturing technology in the nonextraction treatment of Class I malocclusion.

INTRODUCTION: Computer-aided design and manufacturing (CAD-CAM) systems have assisted orthodontists to position brackets virtually. The purpose of this study was to evaluate if a CAD-CAM system could predict the orthodontic treatment outcome of patients with Angle Class I malocclusion with mild crowding or spacing and with no need for orthodontic extraction. METHODS: Using the American Board of Orthodontics Cast-Radiograph Evaluation (ABO-CRE) and color map superimposition, the treated occlusion was compared with the virtual final occlusion of 24 young adults with Class I occlusion. Using eXceed software (eXceed, Witten, Germany), we created the final occlusion prediction for each patient (virtual set up group). A digital model of the final occlusion of each patient was created (treated occlusion group). ABO-CRE score was used to compare groups. In addition, a color map was created for all subjects to access the mean and range values between the virtual set up model and treated occlusion model of each patient. Random and systematic errors were calculated. In addition, chi-square and t test were used. RESULTS: Comparisons between virtual set up occlusion and treated occlusion showed statistically significant differences in 3 out of 7 measurements: interproximal contact score was larger for treated than virtual occlusion (0.45 mm and 0.04 mm, respectively), and the treated occlusion showed larger values than the virtual occlusion for occlusal contacts (14.13 mm and 7.62 mm, respectively) and overjet (7.37 mm and 0.66 mm, respectively). Although the treated occlusion showed a larger score than the virtual occlusion (50.41 mm and 34.58 mm, respectively), there is no significant difference between both. Root angulation decreased (from 1.95 ± 1.29 to 0.65 ± 0.71) because of the treatment. CONCLUSIONS: ABO-CRE overall score presents no difference between groups. In addition, CAD-CAM setup occlusion closely predicts the final teeth alignment and leveling with interarch relationships showing less ABO-CRE score deduction.

Relationships among tongue volume, hyoid position, airway volume and maxillofacial form in paediatric patients with Class-I, Class-II and Class-III malocclusions.

OBJECTIVES: To clarify the associations among tongue volume, hyoid position, airway volume and maxillofacial form using cone beam computed tomography (CBCT) data for children with Class-I, Class-II and Class-III malocclusion. SETTING AND SAMPLE POPULATION: Sixty children (mean age, 9.2 years) divided into Class-I, Class-II and Class-III malocclusion groups according to the A-nasion-B angle. MATERIAL AND METHODS: Cone beam computed tomography was used for three-dimensional reconstruction of the maxillofacial region and airway. The hyoid position and the tongue, airway and oral cavity volumes were evaluated. Upper airway ventilation status was calculated using computational fluid dynamics. The groups were compared using analysis of variance and Kruskal-Wallis tests; relationships among the parameters were assessed using Pearson's and Spearman's rank correlation tests. RESULTS: The tongue volume was larger in Class-III patients (50.63 cm3 ) than in Class-I patients (44.24 cm3 ; P < 0.05). The hyoid position was lower (49.44 cm), and anatomical balance (AB; tongue volume/oral cavity volume; 85.06%) was greater in Class-II patients than in Class-I patients (46.06 cm, 80.57%, respectively; P < 0.05 for both). The hyoid height showed a positive correlation with AB (r = 0.614; P < 0.001). CONCLUSIONS: Children with Class-III malocclusion have large tongue volumes and small AB; the reverse is true for children with Class-II malocclusion. The hyoid position is closely associated with AB in children with malocclusion.

Evaluation of Vestibular Bone Thickness in Class I Malocclusion Treatment With Corticotomy-Assisted Rapid Orthodontics.

BACKGROUND: Corticotomy-assisted rapid orthodontics is a widely used method for speeding up conventional orthodontics. This study (i) evaluates the effects of corticotomy alone, corticotomy combined with bone graft, and corticotomy with platelet-rich fibrin (PRF) on vestibular alveolar bone thickness in patients with class I malocclusion; (ii) compares the treatment time with a conventional orthodontic therapy group, and (iii) investigates the periodontal health of patients who have undergone corticotomy-assisted rapid orthodontics. METHODS: The patients were divided into 3 groups: Group 1 (n = 10) underwent corticotomy alone; Group 2 (n = 10) underwent corticotomy combined with bone graft, and Group 3 (n = 10) underwent corticotomy combined with PRF. In the following stage, vestibular alveolar bone thicknesses were evaluated using 3-dimensional cone-beam computed tomography images. RESULTS: The findings showed that Group 2 achieved a more significant augmentation of the vestibular alveolar bone than Groups 1 and 3 (P = 0.001, P = 0.003), while corticotomy-assisted rapid orthodontics decreased treatment times. Sufficient alveolar bone thickness and preservation of the periodontal health were achieved when the corticotomy procedure was either combined with a bone graft or with PRF in the Class-I malocclusion patients. CONCLUSION: Bone grafts provided better bone thickness at the buccal surface of the anterior teeth of the mandible and maxilla, whereas the thickness of the keratinized gingiva was better with PRF.

Correcting severe scissor bite in an adult.

Scissor bite often remains unnoticed by patients although it can adversely affect facial symmetry, jaw growth, and mastication. This case report illustrates the efficacy of temporary skeletal anchorage devices (TSADs) and a modified lingual arch in correcting severe scissor bite. A 28-year-old woman presented with severe scissor bite in the mandibular right posterior segment. To treat this condition, TSADs were used for maxillary posterior intrusion and a modified lingual arch for buccally uprighting mandibular posterior teeth. Long-term retention records demonstrate stable treatment results.

Chin remodeling in a patient with bimaxillary protrusion and open bite by using mini-implants for temporary anchorage.

Patients with bimaxillary protrusion may have an unattractive profile with a retruded chin contour. Correction of the severely protrusive anterior alveolar bone and teeth combined with a moderate open bite without orthognathic surgery can be challenging. This case report describes the orthodontic treatment of a woman with severe bimaxillary protrusion and a moderate open bite. Excellent chin morphology and facial appearance were obtained with the extraction of 4 first premolars and 4 third molars, and total distalization of both arches with 4 mini-implants, one in each quadrant between the second premolar and the first molar. The total treatment time was 30 months.

Three-dimensional evaluation of craniofacial characteristics related to mandibular asymmetries in skeletal Class I patients.

INTRODUCTION: Our objective was to analyze the characteristics that affect skeletal Class I adults with mandibular asymmetries using cone-beam computerized tomography. METHODS: The sample included cone-beam computerized tomography images of 120 subjects. Asymmetry was determined by the deviation of gnathion from the midsagittal plane and classified as relative symmetry, moderate asymmetry, or severe asymmetry. Maxillary and mandibular measurements were made, and the differences between the contralateral side and the deviated side were evaluated, as well as the differences between the categories of asymmetry. RESULTS: For patients with moderate asymmetry, there were significant differences between the contralateral and deviated sides for some measuments in the transverse and vertical planes. For those with severe asymmetry, statistically significant differences were found between the sides for all measurements, except for the measuments that evaluated the position of the mandibular condyle in the transverse and sagittal directions. Furthermore, a strong correlation was found in patients with severe asymmetry, between the deviation of the mandibular dental midline and the lateral displacement of gnathion. CONCLUSIONS: Patients with relative symmetry had a bilateral balance, whereas those with moderate and severe asymmetries showed several skeletal imbalances. A great deviation of the mandibular dental midline may indicate severe skeletal asymmetry in Class I adults.

Three-dimensional evaluation of dentofacial transverse widths of adults with various vertical facial patterns.

INTRODUCTION: The purpose of this study was to investigate maxillomandibular transverse widths and molar inclinations of adults with hypodivergent, normodivergent, and hyperdivergent facial patterns using cone-beam computed tomography. METHODS: We evaluated Class I subjects (55 men, 66 women) who were divided into hypodivergent (<27°), normodivergent (28°-37°), and hyperdivergent (>38°) groups by their mandibular plane angles. Frontal and coronal views of the images were analyzed. Sex differences, vertical facial pattern differences, and related factors were assessed with independent 2-sample t tests, 1-way analysis of variance followed by post hoc Tukey tests, and Pearson correlation analysis. RESULTS: The hypodivergent group had greater maxillary alveolar widths 7 mm apically from the alveolar crest. The intermolar widths and molar inclinations showed no significant differences among the groups. As the mandibular plane angles increased, interjugular widths, transverse mandibular widths, and buccolingual maxillary alveolar widths at the midroot level decreased, whereas the maxillomandibular width differences and palatal heights increased im both sexes. CONCLUSIONS: An increase in the mandibular plane angle is associated with tendencies of narrow mandibular arches, thinner maxillary alveolar bones at the midroot level, and higher palatal arches in both sexes. Intermolar widths and molar inclinations were not significantly affected by vertical facial patterns.

Nonsurgical correction of a severe anterior open bite with mandibular molar intrusion using mini-implants and the multiloop edgewise archwire technique.

This article reports the case of a 24-year-old man with a large anterior open bite, mild mandibular crowding, increased overjet, no passive lip sealing, and Angle Class I malocclusion. The treatment results were achieved by mandibular molar intrusion using 1.8 × 8.5-mm mini-implants (C-implants) inserted between the mandibular first and second molars bilaterally. A 2.5-mm molar intrusion and open-bite closure occurred within 8 months. The multiloop edgewise archwire technique helped to intrude the posterior teeth. Total treatment time was 20 months. Fifty months postretention records are also presented. The patient achieved a suitable occlusion and satisfactory facial esthetics at the end of treatment and at the 50-month retention check.

Comparison of the occlusal contact area of virtual models and actual models: a comparative in vitro study on Class I and Class II malocclusion models.

BACKGROUNDS: The occlusal registration of virtual models taken by intraoral scanners sometimes shows patterns which seem much different from the patients' occlusion. Therefore, this study aims to evaluate the accuracy of virtual occlusion by comparing virtual occlusal contact area with actual occlusal contact area using a plaster model in vitro. METHODS: Plaster dental models, 24 sets of Class I models and 20 sets of Class II models, were divided into a Molar, Premolar, and Anterior group. The occlusal contact areas calculated by the Prescale method and the virtual occlusion by scanning method were compared, and the ratio of the molar and incisor area were compared in order to find any particular tendencies. RESULTS: There was no significant difference between the Prescale results and the scanner results in both the molar and premolar groups (p = 0.083 and 0.053, respectively). On the other hand, there was a significant difference between the Prescale and the scanner results in the anterior group with the scanner results presenting overestimation of the occlusal contact points (p < 0.05). In Molars group, the regression analysis shows that the two variables express linear correlation and has a linear equation with a slope of 0.917. R2 is 0.930. Groups of Premolars and Anteriors had a week linear relationship and greater dispersion. CONCLUSIONS: Difference between the actual and virtual occlusion revealed in the anterior portion, where overestimation was observed in the virtual model obtained from the scanning method. Nevertheless, molar and premolar areas showed relatively accurate occlusal contact area in the virtual model.

An Evaluation of Mandibular Dental and Basal Arch Dimensions in Class I and Class II Division 1 Adult Syrian Patients using Cone-beam Computed Tomography.

Aim: The aim of this study is (1) to inspect any difference in mandibular arch widths between males and females in class I and class II division 1 (class malocclusions using cone-beam computed tomography (CBCT), (2) to compare the mandibular dental and basal widths between the two groups, and (3) to investigate any possible correlation between dental and basal arch widths in both groups. Materials and methods: The CBCT images of 68 patients aged between 18 and 25 years consisted of 34 class I (17 males and 17 females) and 34 class (17 males and 17 females) who were recruited at the Department of Orthodontics, University of Damascus Dental School (Syria). Using on-demand three-dimensional (3D) on axial views, facial axis points for dental measurements and basal bone center (BBC) points for basal measurements were identified on lower canines and first molars. Dental and basal intercanine width (ICW) and intermolar width (IMW) were measured. Results: Independent t-test showed a statistically significant difference between males and females in several variables in both groups and a statistically significant difference between class I and class groups in the basal ICW for both genders and in the dental ICW for females only (p < 0.05). In class I group, Pearson's correlation coefficients between dental and basal measurements showed a strong correlation in the IMW for both genders (r > 0.73; p < 0.01) and a moderate correlation in females' ICW (r = 0.67; p < 0.01). In the class group, a moderate correlation in females' IMW (r = 0.67; p < 0.01) was found. Conclusion: Females compared with males had narrower dimensions. Class I patients had larger ICW than class II-1 patients in all measurements and had narrower IMW than class in most measurements for both genders. There were moderate-to-strong correlations between dental and basal dimensions. BBC points might be landmarks that accurately represent the basal bone arch. Clinical significance: CBCT-based assessments of dental and basal arch dimensions provide a great opportunity to accurately evaluate these aspects, to enhance clinicians' decisions regarding proper tooth movements, and to achieve good dentoalveolar intra-arch harmony. Keywords: Basal arch, Class I, Class Cone-beam computed tomography, Dental arch, Intercanine width, Intermolar width.

The relationship between the incisor position and lingual surface morphology in normal occlusion.

This study aimed to investigate the relationship between the morphological characteristics of maxillary incisors and the anterior occlusion. The study materials comprised dental casts and lateral cephalograms of 26 modern Mongolian females with Angle Class I normal occlusion (mean age, 21 years 5 months). Computed tomography (CT) images of the dental casts were taken with an X-ray micro-CT system (SMX-100CT, Shimadzu, Kyoto Japan). The thickness of the marginal ridges and incisal edges, and the overjet and overbite, was measured on the three-dimensional images of the dental casts. On the lateral cephalogram, maxillary incisor to sella-nasion plane angle (U1 to SN angle), maxillary incisor to nasion-point A plane distance (U1 to NA distance), mandibular incisor to nasion-point B plane distance (L1 to NB distance), incisor mandibular plane angle, and interincisal angle were measured by tracing the left incisors of the maxilla and mandible. Spearman's single rank correlation coefficients were used to investigate any correlation between measurement items for each maxillary incisor. The thickness of the marginal ridges and incisal edges was positively correlated with the overbite. The thickness of the incisal edges was positively correlated with the irregularity index of the maxilla. There were significant negative correlations between overbite and U1 to SN angle, U1 to NA distance, and L1 to NB distance. Significant positive correlations were noted between the overbite and the overjet. In conclusion, there was no strong relationship between the morphological characteristics of maxillary incisors and the anterior occlusion.

Comparative Evaluation of the Pharyngeal Airway Space in Unilateral and Bilateral Cleft Lip and Palate Individuals With Noncleft Individuals: A Cone Beam Computed Tomography Study.

OBJECTIVE: To evaluate the pharyngeal airway space changes in complete unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP) individuals, and compare with age and sex-matched noncleft (NC) control subjects. DESIGN: Retrospective study. SETTING: Cleft and Craniofacial Centre, KK Women's and Children's Hospital, Singapore. MATERIALS AND METHODS: Twenty UCLP (mean age: 13.4 ± 0.5 years), 18 BCLP (mean age: 13.5 ± 0.5 years) and 20 skeletal Class I subjects (mean age: 13.4 ± 0.6 years) were included in the study. Cone beam computed tomography scans were assessed for pharyngeal airway space (PAS) (oropharyngeal, nasopharyngeal, total airway space volume), and compared with PAS of age and sex-matched skeletal Class I NC individuals. RESULTS: Pharyngeal airway space showed statistically significant differences in the UCLP, BCLP, and NC control subjects. Oropharyngeal (9338 ± 1108 mm3, P < .05), nasopharyngeal (2911 ± 401 mm3, P < .05), and total airway space (12 250 ± 1185 mm3, P < .05) volumes of BCLP individuals showed significant reduction in comparison to UCLP and NC. There were no gender differences of PAS in any of the groups tested (P > .05). CONCLUSION: The pharyngeal airway space was significantly reduced in the BCLP group than were those in UCLP and control groups. This reduced PAS should be taken into account when planning treatment for these individuals.

Diagnosis and treatment planning of orthodontic patients with 3-dimensional dentofacial records.

INTRODUCTION: Cephalometrics has been the foundation of orthodontic diagnosis for many years. However, for many orthodontic patients, a lateral cephalogram might not be necessary. The aim of this study was to compare the diagnosis and treatment planning agreement between standard records and nonradiographic 3-dimensional (3D) dentofacial photogrammetry records. METHODS: Twenty patients had standard orthodontic records taken for their treatment as well as extraoral and intraoral 3D images. Twelve evaluators examined the standard records and then completed diagnosis and treatment planning questionnaires. They repeated the process 4 to 6 weeks later by using 3D photographic images along with the panoramic radiographs. Each evaluator also evaluated 2 random orthodontic cases twice with each method to evaluate consistency within each method. At the end of study, each evaluator was asked to complete a survey to document his or her experiences with the 3D photogrammetry method. Descriptive and kappa statistics were used to determine the agreement. RESULTS: Most diagnosis parameters had fair agreement between the methods and within each method. Skeletal and dental relationships had excellent agreement between and within the methods as well as most treatment decisions such as the need for extractions and surgery. Most evaluators (91.7%) thought that cephalometric x-rays would be needed only some of the time in diagnosis and treatment planning. Most evaluators (83.33%) thought that cephalometric radiographs are not needed in patients with a Class I ± a quarter cusp with crowding or spacing. CONCLUSIONS: Most diagnostic decisions had fair agreement within and between the 2 methods. The decision to extract and the need for orthognathic surgery had excellent agreement between the cephalometric and photogrammetric methods. The majority of examiners agreed that patients with Class I malocclusions ± a quarter cusp with no obvious skeletal discrepancy can be diagnosed and planned without a cephalometric radiograph.

Transverse dental compensation in relation to sagittal and transverse skeletal discrepancies in skeletal Class III patients.

INTRODUCTION: The purposes of this study were to compare the buccolingual inclinations of the posterior teeth in skeletal Class III patients with and without facial asymmetry with those of skeletal Class I patients and to investigate their relationships with sagittal and transverse skeletal discrepancies. METHODS: Sixty-three skeletal Class III adult patients were divided into 2 groups according to the degree of menton deviation: a symmetry group with deviation less than 2 mm (n = 30), and an asymmetry group with deviation greater than 4 mm (n = 33). The control group comprised 25 skeletal Class I patients. The buccolingual inclinations of the posterior teeth measured on cone-beam computed tomography images were compared among the 3 groups, and regression analysis was performed to investigate the relationships between the inclinations and the sagittal and transverse skeletal discrepancies. RESULTS: The symmetry group showed greater buccal inclinations of the maxillary posterior teeth and lingual inclinations of the mandibular second molars than did the control, and this was correlated with the ANB angles. The deviated sides in the asymmetry group showed the greatest transverse dental compensation, which was correlated with menton deviation, whereas the nondeviated sides showed no significant transverse dental compensation. CONCLUSIONS: Transverse dental compensation is closely related to sagittal and transverse skeletal discrepancy in skeletal Class III patients.

Influence of different setups of the Frankfort horizontal plane on 3-dimensional cephalometric measurements.

INTRODUCTION: The Frankfort horizontal (FH) is a plane that intersects both porions and the left orbitale. However, other combinations of points have also been used to define this plane in 3-dimensional cephalometry. These variations are based on the hypothesis that they do not affect the cephalometric analysis. We investigated the validity of this hypothesis. METHODS: The material included cone-beam computed tomography data sets of 82 adult subjects with Class I molar relationship. A third-party method of cone-beam computed tomography-based 3-dimensional cephalometry was performed using 7 setups of the FH plane. Six lateral cephalometric hard tissue measurements relative to the FH plane were carried out for each setup. Measurement differences were calculated for each pair of setups of the FH plane. The number of occurrences of differences greater than the limits of agreement was counted for each of the 6 measurements. RESULTS: Only 3 of 21 pairs of setups had no occurrences for the 6 measurements. No measurement had no occurrences for the 21 pairs of setups. Setups based on left or right porion and both orbitales had the greatest number of occurrences for the 6 measurements. CONCLUSIONS: This investigation showed that significant and undesirable measurement differences can be produced by varying the definition of the FH plane.