[Treatment of class II for growing patients by clear aligners: which protocol?]

INTRODUCTION

Skeletal class II, frequently associated with retromandibular and overjet > 2 mm, lead to functional and aesthetic damage, that orthodontic treatment has to correct. The aim of this article is to describe a treatment protocol by aligners for class II growing patients according to the value of the class II and the maturity state of cervical vertebrae.

MATERIALS AND METHODS

Through clinical cases, this article will present three different therapeutic approaches depending on the growth state.

RESULTS

The study of the auxologic potential and determination of the bone age (radiological analysis of the maturation of the cervical vertebrae) will allow to determine the best moment to treat class II and the most appropriate therapeutic attitude according to growing state.

DISCUSSION

This study before treatment is essential to adapt an individualized clinical protocol to each patient. In this way, aligners are devices that respond well to this imperative because they are customizable in view of the strategy and the treatment plan considered by the practitioner. We must keep in mind, however, that with any therapy, it is essential to ensure good patient compliance.

Assessment of dental arches in patients with Class II division 1 and division 2 malocclusions using 3D digital models in a Syrian sample

AIM

(1) to evaluate the applicability of using 3D digital models in the assessment of Class II Division 1 (Cl II-1) and Class II Division 2 (Cl II-2) malocclusion in a Syrian sample, (2) to detect any significant differences between the two groups in tooth and arch widths, anterior (ABR) and overall Bolton ratios, PAR Index, and (3) to detect any gender differences in these variables.

DESIGN AND SETTING

observational, cross-sectional study for descriptive and analytical purposes at the Orthodontic Dept., University of Al-Baath Hamah Dental School, Hamah, Syria.

PARTICIPANTS

A disproportionate multi-stratified random sampling was employed to select 36 Cl II-1 and 36 Cl II-2 patients (female-to-male ratio was 1:1 in each group). 3D digital models (O3DM) with a dedicated programme were used to measure dental arch variables.

RESULTS

Significant differences were observed between the two groups in the mesiodistal widths of some teeth but not in the dental arch widths. The prevalence of 'discrepancy cases' in Anterior Bolton Ratios (ABRs) was 33.33% and 41.67% in Cl II1 and Cl II2 groups, respectively. The mean PAR Index score was 25.36 and 20.82 for Cl II1 and Cl II2 groups, respectively (p=0.009).

CONCLUSIONS

(1) 3D digital models enabled fast, accurate and reliable measurements of dental arch characteristics in patients with Class II malocclusion. (2) Insignificant differences between Cl II1 and Cl II2 patients were observed regarding Bolton's ratios and transverse arch measurements. (3) Sexual dimorphism was observed in mesiodistal tooth widths and in dental arch widths, but not in Bolton's ratios and PAR Index scores.

Permanent mandibular canine(s) impaction: expansion of our understanding

INTRODUCTION

Eruption disturbances, tooth size and specific malocclusions are known to be genetically influenced. The clinical association between these traits may indicate common genetic controls.

OBJECTIVES

A cross-sectional clinical study was designed to test the null hypothesis that the maximum mesiodistal crown diameter (MMD) of maxillary and mandibular central and lateral incisors and the prevalence of various classes of incisor relationships (Class I, II/1, II/2 and III) do not differ between the subjects with and without permanent mandibular canine(s) impaction.

METHODS

Dental models of 43 subjects diagnosed with mandibular canine(s) impaction (Impaction Group - IG) were compared with those of 86 subjects of a control reference sample (Control Group - CG). Independent t-test and chi-square tests were used to determine the association between mandibular canine(s) impaction and the MMD of the incisors and the incisor relationship, respectively. The likelihood of various incisor relationships between the IG and CG were evaluated according to odds ratios.

RESULTS

A fourfold increase (p < 0.0001) in the overall frequency of Class II/2 incisor relationship was observed in the IG when compared to controls.

CONCLUSIONS

The null hypothesis was rejected. Subjects with mandibular canine(s) impaction appeared to be characterised with wider incisors and a remarkably high rate of Class II/2 malocclusion. This information assists the understanding of genetically controlled dental anomalies, which are likely to coexist with mandibular canine(s) impaction.

Improvement in Smoothness of the Chewing Cycle Following Treatment of Anterior Crossbite Malocclusion: A Case Report

This is a report of a case in which improvement in masticatory jaw movement kinematics occurred following orthodontic treatment. A patient who demonstrated a skeletal Class II jaw relationship, with anterior crossbite between the right upper and lower lateral incisors, underwent treatment with an edgewise appliance. The trajectories and smoothness of the patient's jaw-closing movement were compared before and after orthodontic treatment. The correction of the anterior crossbite allowed the patient to consistently close the jaw with wider lateral excursion. Furthermore, after treatment, smoothness of the jaw-closing movements increased significantly, and the velocity profile was characterized as closer to that predicted by the minimum jerk (maximum smoothness) kinematic model. These findings suggest the value of trajectory smoothness (jerk-cost) as an objective indicator of kinematic improvement in gum chewing. In addition, the correction of anterior crossbite is demonstrated to enable the patient to perform smoother jaw-closing movements during chewing.

Class II malocclusion division 1: a new classification method by cephalometric analysis

AIM

The purpose of this study was to analyse the craniofacial and dentofacial skeletal characteristics in untreated subjects with Class II, division 1 malocclusion by mandibular retrusion and to identify different types and their prevalence.

MATERIALS AND METHODS

In 152 subjects with Class II, division 1 malocclusion by mandibular retrusion, the differences were determined by lateral cephalograms analysis of variance and chi-square test, respectively. P<0.05 was considered significant. Seven types of mandibular retrusion were identified: three pure, dimensional, rotational and positional, and four mixed.

RESULTS

All patients showed significant inter-group differences with P between 0.005 and 0.001. The dimensional type was the most common (28.9%) and the rotational-positional type was the rarest (5.9%). The pure dimensional type had the shortest mandibular body; the pure rotational type had larger SN/GoMe and the lowest AOBO; the pure positional type presented the flattest cranial base, high AOBO. In the mixed types, dento-skeletal features changed depending on how the main types assorted.

CONCLUSIONS

Identifying the type of mandibular retrusion is important for differential diagnosis in clinical practice and research.

[A comparative study of the transverse dimensions of the dental arches between Class I dental occlusion and Class II1 and Class II2 malocclusions]

The purpose of this work was to compare transverse dimensions of the maxillary and mandibular arches in the canine and molar region between three groups of patients: the first group had an occlusion in class II division 1, the second one a dental class II division 2 and the third one, a class I bite. Our sample is composed of 94 patients, with an average age of 20 +/- 3 years: 31 patients presented a class I occlusion, 33 a class III1 and 30 cases presented a dental class II2. For this study, we measured, on the maxillary and mandibular dental casts of each patient, the intercanine and intermolar canine (central inter fossa). Comparison of variables was conducted using the variance analysis ANOVA; the selected post-hoc test is the Bonferrroni test. On the basis of our study, we can get the following results: Maxillary intercanine distance is narrower in class II1 compared to class II2 of 2 mm "p < 0.05". Mandibular intercanine distance is narrower in class III1 compared to class II2 of 1, 3 mm "p < 0.05". Maxillary intermolar distance (inter fossa) is narrower in class II1 compared to class I of 2, 2 mm "p < 0.05".

Dermatoglyphics--a marker for malocclusion?

INTRODUCTION

Dermatoglyphics is the study of dermal ridge configurations on palmar and plantar surfaces of hands and feet. Dermal ridges and craniofacial structures are both formed during 6-7th week of intra-uterine life. It is believed that hereditary and environmental factors leading to malocclusion may also cause peculiarities in fingerprint patterns.

OBJECTIVE

To study and assess the relationship between fingerprints and malocclusion among a group of high school children aged 12-16 years in Dharwad, Karnataka, India.

DESIGN

A total of 696 high school children aged 12-16 years were randomly selected. Their fingerprints were recorded using duplicating ink and malocclusion status was clinically assessed using Angle's classification.

RESULTS

Chi-square analysis revealed statistical association between whorl patterns and classes 1 and 2 malocclusion (p < 0.05). However, no overall statistical association was observed between fingerprint patterns and malocclusion (p > 0.05).

CONCLUSION

Dermatoglyphics might be an appropriate marker for malocclusion and further studies are required to elucidate an association between fingerprint patterns and malocclusion.

Dental and alveolar arch asymmetries in normal occlusion and Class II Division 1 and Class II subdivision malocclusions

AIM

To compare the degree of intra- and interarch dentoalveolar asymmetry among patients with a normal occlusion, Class II Division 1 malocclusion, and Class II subdivision malocclusion.

METHODS

The sample comprised dental casts of 150 (72 males [ages 22. 1 +/- 3.11 and 78 females [ages 21.1 +/- 2.1]) normal occlusion subjects, 106 (45 males [ages 17.8 +/- 1.8] and 61 females [ages 16.5 +/- 2.91) Class II Division 1 patients, and 40 (18 males [ages 15.8 +/- 2.8] and 22 females [ages 15.2 +/- 3.3]) Class II subdivision malocclusions. Maxillary and mandibular reference lines were constructed and used for the intraarch asymmetry measurements. Thirty-six width measurements were performed on the dental casts of each subject. Analysis of variance (ANOVA) was used for comparisons of the groups, and Pearson's correlation coefficients were computed to determine the interarch associations.

RESULTS

No statistically significant intra-arch asymmetry was found for maxillary and mandibular dental arch and alveolar width in any of the three groups. All variables were larger on the right side in the normal occlusion subjects. Further, the left side maxillary dental and alveolar arch width measurements were larger in the Class II Division 1 group. None of these differences, however, were statistically significant. In the Class II subdivision group, only the Class II sides' mandibular dental arch measurements were larger (P < .05). Maxillary and mandibular total dental arch and alveolar width dimensions differed among the groups (P < .001). Except for maxillary and mandibular canine alveolar width, opposing interarch dental and alveolar landmarks were significantly correlated with the transverse dimensions.

CONCLUSION

Although some landmarks in the current study showed statistically significant and insignificant differences, the mean arithmetic differences were small, inconsistent, and not likely clinically important.

Arch Widths in Class II-2 Adults Compared to Adults with Class II-1 and Normal Occlusion

Objective: To compare (1) arch widths in adults with Class II division 2 (II-2), Class II division 1 (II-1), and Class I normal occlusions, (2) genders, (3) gender dimorphism, (4) differences between maxillary and mandibular arch widths, and to (5) develop adult norms for arch widths.

Materials and Methods: Subjects were white Americans with no history of orthodontic treatment. Arch width dimensions measured were: intercanine, intermolar, and molar alveolar in both arches. Analysis of variance (ANOVA) and Duncan's test were used to compare groups.

Results: Comparison of pooled genders showed the II-2 group had maxillary arch widths significantly smaller than the normal occlusions and significantly larger than the II-1 group. All groups had similar mandibular intercanine and alveolar widths. The II-2 and II-1 groups had similar mandibular intermolar widths, both significantly smaller than normal occlusions. The II-2 group had a maxillary/mandibular intermolar difference significantly smaller than the normal occlusions, and significantly less negative than the II-1 group. Gender comparisons in two of six widths showed normal and II-2 male subjects were similar, and in six of six widths normal and II-2 female subjects were similar; in five of six widths II-2 and II-1 male and female subjects were similar. Gender dimorphism occurred in five of six widths in normal occlusions, four of six widths in II-2, and one of six widths in II-1.

Conclusions: Arch width dimensions of II-2 subjects were intermediate between normal and II-1 occlusions. In both Class II malocclusions, the process that narrows arch widths was more pronounced in male than in female subjects.

[The Class II subdivision or acquired unilaterally dominant mastication syndrome]

Unilateral disto-occlusion of the molars and the canine teeth, described by Angle as Class II subdivision, is often characterized by asymmetric development of the maxillae in conjunction with a disturbance in physiological mastication. In addition to the unilateral malposition of the molars and the canine, this Class II subdivision condition is routinely accompanied by an ensemble of symptoms that the authors propose regrouping under the designation "children's acquired unilaterally dominant mastication syndrome". They use several clinical examples to illustrate the diagnosis of this condition that they consider to be a syndrome of craniofacial asymmetry.

Class II subdivision malocclusion types and evaluation of their asymmetries

INTRODUCTION

The primary objective of this study was to determine, by means of frontal photographic evaluation, the distribution of the 2 main types of Class II subdivision malocclusions. The secondary objective was to compare the dentoskeletal asymmetries in these 2 types with a group of normal-occlusion subjects by using submentovertex and posteroanterior radiographs.

METHODS

The experimental group included 44 untreated Class II subdivision malocclusion subjects with a mean age of 15.3 years. The control group included 30 subjects with normal occlusions with a mean age of 22.4 years. All had full complements of permanent teeth up to the first molars and had not received orthodontic treatment. Type 1 Class II subdivision malocclusion is coincidence of the maxillary dental midline with the facial midline and deviation of the mandibular midline. Type 2 has the opposite characteristics. The frontal photographs were evaluated subjectively by 2 examiners. In the submentovertex and posteroanterior radiographs, symmetry was assessed by measuring the relative difference in the spatial positions of dentoskeletal landmarks between the right and left sides. Independent t tests were used to compare the dentoskeletal asymmetries of types 1 and 2 with the normal-occlusion group.

RESULTS AND CONCLUSIONS

The results showed that 61.36% had type 1, 18.18% had type 2 Class II subdivision malocclusion, and 20.45% had mixed characteristics. The predominant asymmetric dentoalveolar characteristics of both types of Class II subdivision malocclusions were evident when individually compared with a normal-occlusion control group. There was a tendency for the type 1 subjects to have greater mandibular asymmetry than type 2, as compared with the control group.

[Cephalometric comparisons of the craniofacial characteristics of Class II 1 malocclusions with different vertical types in adolescences]

PURPOSE

To compare the craniofacial characteristics in Class II(1) malocclusions with different vertical types in adolescence.

METHODS

The sample, including 60 males and 60 females, was divided into three groups equally based on their FMA degrees (high-angle group, average-angle group, low-angle group and normal occlusion group). Cephalograms were traced for all the subjects. Data were obtained to perform analysis of variance and LSD multiple range test.

RESULTS

1. The vertical growth of the anterior part of maxilla was greater than the posterior part in the three groups with Class II(1) malocclusion. The vertical dimension of the composite ramus-cranial floor was deficient relative to that of anterior maxilla in the high-angle and average-angle groups, the mandible rotated backward, especially in the high-angle group. In the low-angle group, the vertical dimension of the composite ramus-cranial floor grew excessively relative to that of posterior maxilla. The palatal plane and mandible plane rotated forward and upward. 2. The dentoalveolar characteristics of Class II(1) malocclusion group showed that: U6 tipped distally, the dentoalveolar height of L6 decreased, the functional occlusal plane (FOP) of average-angle group deviated away from the neutral occlusal axis (NOA), and rotated downward. In the high- angle group, the FOP deviated away from the NOA severely. The vertical dentoalveolar heights of U6 were normal. In the low-angle group, the vertical dentoalveolar heights of U6, the dentoalveolar height of L6 decreased, the angle of FOP between NOA showed no significantly difference from normal-occlusion group.

CONCLUSION

There were different craniofacial vertical characteristics of Class II(1) malocclusion with different vertical types in adolescences. Different methods should be used to control the vertical dimensions in different types.

Dental and alveolar arch widths in normal occlusion, class II division 1 and class II division 2

The aim of this study was to compare the transverse dimensions of the dental arches and alveolar arches in the canine, premolar, and molar regions of Class II division 1 and Class II division 2 malocclusion groups with normal occlusion subjects. This study was performed using measurements on dental casts of 150 normal occlusion (mean age: 21.6 +/- 2.6 years), 106 Class II division 1 (mean age: 17.2 +/- 2.4 years), and 108 Class II division 2 (mean age: 18.5 +/- 2.9 years) malocclusion subjects. Independent-samples t-test was applied for comparisons of the groups. These findings indicate that the maxillary interpremolar width, maxillary canine, premolar and molar alveolar widths, and mandibular premolar and molar alveolar widths were significantly narrower in subjects with Class II division 1 malocclusion than in the normal occlusion sample. The maxillary interpremolar width, canine and premolar alveolar widths, and all mandibular alveolar widths were significantly narrower in the Class II division 2 group than in the normal occlusion sample. The mandibular intercanine and interpremolar widths were narrower and the maxillary intermolar width measurement was larger in the Class II division 2 subjects when compared with the Class II division 1 subjects. Maxillary molar teeth in subjects with Class II division 1 malocclusions tend to incline to the buccal to compensate the insufficient alveolar base. For that reason, rapid maxillary expansion rather than slow expansion may be considered before or during the treatment of Class II division 1 patients.

A comparative study of cephalometric and arch width characteristics of Class II division 1 and division 2 malocclusions

The aim of this compound cephalometric and arch-width study was to determine any dental and/or skeletal differences between subjects with Class II division 1 and Class II division 2 malocclusions. The dento-skeletal characteristics of Class II subjects were evaluated using lateral cephalometric radiographs and dental casts of 90 untreated patients. The sample included 46 Class II division 1 patients (19 girls and 27 boys) with a mean age of 15.27 +/- 2.48 years, and 44 Class II division 2 patients (27 girls and 17 boys) with a mean age of 15.95 +/- 3.25 years. The intermolar, interpremolar and intercanine measurements were carried out on study models. The radiographs were digitized and processed using Dolphin Imaging software. In addition to standard descriptive statistical calculations, an independent samples t-test was carried out in order to compare the two groups. The non-parametric Mann-Whitney U test was utilized for the parameters for the data which were not normally distributed. The only statistically significant difference between the groups for the study model measurements was mandibular intercanine width. The cephalometric results revealed that SNB angle was responsible for the skeletal sagittal difference between the two groups. In addition, the Class II division 1 group had higher vertical proportions and the Class II division 2 group a more concave profile with a prominent chin. The sagittal skeletal pattern of Class II division 2 subjects was found to be very similar to the Class I skeletal relationship, with no evidence of any mandibular restriction.

[The Procuste superimpositions: its value in the study of typology and its development during Edgewise Tweed-Merrifield treatment]

By transforming all figures into the same size, the Procruste mathematical superimpositions system allows orthodontists to analyze and compare geometric shapes whose different areas and forms would otherwise have made comparison impossible. Procruste is, accordingly, particularly useful in the study of facial types. In this retrospective study we analyzed the effects exerted by both growth and Edgewise Tweed Merrifield treatment upon changes in patients' typology of three different facial types. One hundred patients with Class II dental malocclusions were divided into three groups of deep bite, normal bite, and open bite. We found no significant statistical difference in the effects of treatment and of growth on modification of "form" of the facial skeleton as seen on profile cephalograms of the three categories. Patients in all the groups showed an average anterior rotation of the mandible.

Assessment of open and incomplete bite correction by incisor overlap and optical density of polyvinyl siloxane bite registration

Open bite (OB) is a generalized term, which could incorporate subgroups that react differently to vertical correction. The objectives of the present study were to detect vertical treatment changes in incomplete bite (IB: inter-incisor overlap with no lower incisor contact with teeth or palate) and OB (no inter-incisor overlap) groups compared with a complete bite (CB: inter-incisor overlap with full lower incisor contact with teeth or palate) control group, to evaluate treatment response of the central and lateral incisors, and to study the vertico-sagittal interaction. Dental casts were taken at three time points, pre-treatment, post-treatment, and after one year of retention, from 54 Class II patients (22 males and 32 females with a mean age of 11 years 6 months) divided into three groups: CB (n = 21), IB (n = 18) and OB (n = 15). Measurements included incisor overlap (mm) and optical density (OD/mm2) of occlusal bite registration made of polyvinl siloxane. Both CB and IB groups demonstrated post-retention bite opening. However, bite opening in the CB group was three times greater than that in the IB group (e.g. lower lateral = -1.42 mm, 118 OD/mm2 versus -0.40 mm, 107 OD/mm2). Conversely, the OB group showed a significant (P < 0.001) bite closure (e.g. lower lateral = 1.30 mm, -377 OD/mm2). Overjet changes affected OD measurements, causing diversity in OD and millimetric measurements of the lateral incisors in the IB group. In conclusion, the OB group demonstrated a significant stable vertical correction; a post-treatment non-contact inter-incisor relationship was determined by a vertico-sagittal relapse; and full compensation of an IB was not possible.

Masticatory performance in children and adolescents with Class I and II malocclusions

It is not fully understood whether masticatory performance is compromised in individuals with the more common forms of malocclusion (i.e. Class I and Class II). The aim of this prospective investigation was to establish the relationships between masticatory performance, malocclusion (type and severity), age, body size and gender, in children and adolescents. A total of 335 individuals were examined at the average ages of 6, 9, 12 and 15 years. Each subject's occlusal status was described by Angle classification and by the Peer Assessment Ratio (PAR) index. Masticatory performance was quantified by the median particle size (MPS) and the broadness of particle distribution using artificial food. Masticatory performance improved significantly with age. The 6-year-old children were less able to break down the food particles (MPS 4.20 mm2) than the 15 year olds (MPS 3.24 mm2). Analysis of covariance showed that age differences in performance are related to an increase in body size. There were statistically significant differences in masticatory performance between children with normal occlusion and those with a Class I malocclusion; no differences were found between normal occlusion and Class II malocclusion. Gender differences did not explain the variation in masticatory performance. It is concluded that occlusal indices are not reliable predictors of masticatory performance. Traditional descriptors of malocclusion type and severity apparently cannot explain most of the variation in masticatory performance in children and adolescents.

Common factors among the major malocclusions

Dental practitioners tend to classify malocclusions in a schematic fashion often forgetting the full possibilities of characteristics related to a particular situation or malocclusion. This paper is designed to clarify and describe the different malocclusions, stressing the multiple faces of Class I in the mixed dentition based on the previous work of Drs. Anderson, Dewey and Sim. The description of all the major malocclusions is included with their facial, skeletal, dental and functional characteristics. Guidelines for diagnosis and treatment planning with a summary of possible difficulties in treatment are also discussed.

Malocclusion and crowding in an orthodontically referred Turkish population

This study was conducted to evaluate malocclusion and crowding in 1356 patients (793 girls, 563 boys) referred to the Department of Orthodontics, Suleyman Demirel University, Turkey. Class I was the most frequently seen malocclusion in this referred Turkish orthodontic population whereas Class II, division 2 was the least frequently seen. Comparison of mean ages of the malocclusion groups indicated statistically significant difference between Class I and Class II, division 1 groups (P < .05). The lowest mean age was present in the Class II, division 1 group. Mild mandibular crowding was the most common finding whereas severe mandibular crowding was seen least frequently in all malocclusion groups. Cross tabulation of maxillary and mandibular crowding indicated that mild maxillary and severe mandibular crowding in the same patient was rarely seen in all types of malocclusions. Moderate maxillary and severe mandibular crowding in the same patient was another rare finding for all malocclusion groups.

Stability of Class II, division 1 treatment with the headgear-activator combination followed by the edgewise appliance

This study assessed the stability of the headgear-activator combination treatment, followed by edgewise mechanotherapy, 5.75 years after treatment. The experimental group consisted of 23 patients who were evaluated during treatment and after treatment. Two compatible control groups consisting of 15 Class II, division 1 patients and 24 normal occlusion individuals were used. This enabled us to evaluate the changes during treatment and after treatment, respectively. Results showed that the anteroposterior dentoalveolar changes and the maxillary and the mandibular positions remained stable in the long term. However, there was a slight relapse of the maxillomandibular relationship probably because the maxilla resumed its normal development and the mandibular growth rate was smaller than in the control group. The overbite demonstrated a statistically significant relapse that was directly proportional to the amount of its correction. There were low but significant inverse correlations between the changes in Go-Gn during and after treatment. These included the uprighting of the maxillary incisors, labial tipping of the mandibular incisors, and the amount of molar relationship correction during treatment and their stability. Active retention time, length of posttreatment period, initial Class II malocclusion severity (ANB and Wits), and initial molar relationship did not present any correlation with molar relationship and overjet relapse. However, the initial overjet presented a low but statistically significant correlation with molar relationship relapse and overjet relapse.

A new approach of assessing sagittal discrepancies: the Beta angle

An accurate anteroposterior measurement of jaw relationships is critically important in orthodontic diagnosis and treatment planning. The angular and linear measurements that have been proposed can be inaccurate because they depend on various factors. The purpose of this study was to establish a new cephalometric measurement, named the Beta angle, to assess the sagittal jaw relationship with accuracy and reproducibility. This angle uses 3 skeletal landmarks-point A, point B, and the apparent axis of the condyle-to measure an angle that indicates the severity and the type of skeletal dysplasia in the sagittal dimension. Seventy-six pretreatment cephalometric radiographs of white patients were selected on the basis of 4 criteria that indicate a normal Class I skeletal pattern; the mean and the SD for the Beta angle were calculated. This group was compared with Class II and Class III skeletal pattern groups. After using the 1-way analysis of variance and the Newman-Keuls test and running receiver-operating-characteristics curves, we obtained results that showed that a patient with a Beta angle between 27 degrees and 35 degrees can be considered to have a Class I skeletal pattern. A more acute Beta angle indicates a Class II skeletal pattern, and a more obtuse Beta angle indicates a Class III skeletal pattern.