A Comparison of Three Orthodontic Treatment Indices with Regard to Angle Classification.

OBJECTIVES: To calculate the agreement between the Dental Aesthetic Index (DAI) and the Index of Complexity, Outcome and Need (ICON) in assessing orthodontic treatment need and to determine correlations between the Peer Assessment Rating (PAR) and DAI and ICON scores according to Angle classification among patients referred for orthodontic evaluation. STUDY DESIGN: This study included 457 randomly selected patients between 9 to 17 years of age. Patients were divided into four groups according to Angle classification [Class I (n=154), Class II division 1(Class II/1) (n=155), Class II division 2(Class II/2) (n=52) and Class III (n=96)]. Relationships between PAR scores and ICON and DAI scores were evaluated with the Spearman correlation test. Unweighted kappa statistics were used to analyse agreement between the ICON and DAI on the need for treatment, according to Angle classification. RESULTS: Class I malocclusions scored significantly lower than other Angle classifications in all indices. Both the ICON and DAI showed significant positive correlations with the PAR in the general study population. For Class II/2 patients, no correlation was found between PAR and DAI scores. There was significant agreement between the ICON and DAI on treatment need among Class I, Class II/1 and Class II/2 patients however, no agreement was found for Class III malocclusions. CONCLUSIONS: The ICON, DAI and PAR produce similar results and can be used interchangeably for the general orthodontic patient population. However, based on Angle classification, prominent differences exist in scoring certain occlusal features.

Relationship between mandibular incisor irregularity and type of occlusion in ankyloglossia.

PURPOSE: To investigate the relationship between the lingual frenulum length with mandibular incisor irregularity and type of occlusion in children with ankyloglossia. MATERIALS AND METHODS: Eighty children aged between 7 and 12 years with ankyloglossia enrolled in the study. The patients were classified according to Kotlow's classification. Mandibular incisor crowding was measured and the molar relationship was determined. The data were analysed statistically using Fisher's exact test, X2 and Pearson's correlation. RESULTS: Of the 80 patients, 45 (56.3%) had mild, 23 (28.8%) had moderate and 12 (15%) had severe ankyloglossia. Fifty-nine (73.8%) of the patients had mild irregularity, 18 (22.5%) had moderate and 3 (3.8%) had severe irregularity. In 56 (70%) of the patients, Class I occlusion was observed, 17 (21.3%) had Class II and 7 (8.8%) had Class III occlusion. No significant differences were found between types of ankyloglossia with mandibular incisor irregularity and occlusion types. A significant positive correlation was determined between the length of the lingual frenulum length and mandibular incisor irregularity. There were significant positive correlations between the lingual frenulum length, incisor irregularity and age. CONCLUSION: Mild and moderate types of ankyloglossia are unrelated to mandibular incisor crowding and occlusion type.

Treatment outcomes after extraction and nonextraction treatment evaluated with the American Board of Orthodontics objective grading system.

INTRODUCTION: A controversy exists regarding better treatment outcomes when patients treated with extractions and without extractions are evaluated. The aims of this study were to use the American Board of Orthodontics objective grading system (ABO-OGS) to evaluate and compare treatment outcomes in extraction vs nonextraction Class I patients and to determine whether the treatment choice was a significant predictor of success according to the ABO examination. METHODS: Discriminant analysis was applied to a sample of 542 patients, and a borderline sample of 55 patients was obtained. Of these patients, 25 were treated with extractions and 30 without extraction of the 4 first premolars. Treatment results were then assessed using the 8 variables of the ABO-OGS. RESULTS: The total scores ranged from 11 to 41 (mean, 27.04; SD, 6.3) for the extraction group and from 16 to 44 (mean, 29.07; SD, 7.1) for the nonextraction group. The variable of buccolingual inclination had the highest scores in both groups (8.44 [SD, 3.3] for the extraction group; 8.90 [SD, 3.8] for the nonextraction group; mean difference, 0.46; 95% CI, -1.44, 2.37; P = 0.63). However, no statistically significant intergroup differences were found, either between the scores of the 8 ABO-OGS variables or between the total ABO-OGS scores. Regarding the success rates of the ABO examination, no significant difference was found between the 2 treatment groups (odds ratio, 2.55; 95% CI, 0.74, 0.85; P = 0.14). CONCLUSIONS: For a patient with a borderline Class I malocclusion, extraction and nonextraction treatment can achieve the same quality of results as assessed by the ABO-OGS. Additionally, in these Class I patients, the treatment modality (extraction or nonextraction) is not a significant predictor of passing the ABO examination.

Influence of initial occlusal severity on time and efficiency of Class I malocclusion treatment carried out with and without premolar extractions.

INTRODUCTION: The aim of this retrospective study was to compare the occlusal outcomes, duration and efficiency of Class I malocclusion treatment carried out with and without premolar extractions in patients with different degrees of initial malocclusion severity. METHODS: Complete records of 111 patients were obtained and divided into two groups: Group 1 consisted of 65 patients at an initial mean age of 13.82 years old treated with four premolar extractions; whereas Group 2 consisted of 46 patients at an initial mean age of 14.01 years old treated without extractions. Two subgroups were obtained from each group (1A, 1B, 2A and 2B) with different degrees of malocclusion severity according to the initial values of PAR index. Compatibility was assessed using chi-square and t-tests. The subgroups were compared by means of Analysis of Variance (ANOVA). The variables that might be related to treatment duration and efficiency were assessed using the multiple linear regression analysis. RESULTS: Initial malocclusion severity was positively related to the amount of occlusal correction and consequently to a higher efficiency index. Moreover, extraction protocol showed a positive relationship with treatment duration and a negative relationship with treatment efficiency. CONCLUSION: Extraction and non-extraction protocols for correction of Class I malocclusion provide similar satisfactory results; however, the extraction protocol increases the overall treatment duration. Orthodontic treatment is more efficient in cases with high initial malocclusion severity treated with a non-extraction protocol.

Influence of initial occlusal severity on time and efficiency of Class I malocclusion treatment carried out with and without premolar extractions

INTRODUCTION: The aim of this retrospective study was to compare the occlusal outcomes, duration and efficiency of Class I malocclusion treatment carried out with and without premolar extractions in patients with different degrees of initial malocclusion severity. METHODS: Complete records of 111 patients were obtained and divided into two groups: Group 1 consisted of 65 patients at an initial mean age of 13.82 years old treated with four premolar extractions; whereas Group 2 consisted of 46 patients at an initial mean age of 14.01 years old treated without extractions. Two subgroups were obtained from each group (1A, 1B, 2A and 2B) with different degrees of malocclusion severity according to the initial values of PAR index. Compatibility was assessed using chi-square and t-tests. The subgroups were compared by means of Analysis of Variance (ANOVA).The variables that might be related to treatment duration and efficiency were assessed using the multiple linear regression analysis. RESULTS: Initial malocclusion severity was positively related to the amount of occlusal correction and consequently to a higher efficiency index. Moreover, extraction protocol showed a positive relationship with treatment duration and a negative relationship with treatment efficiency. CONCLUSION: Extraction and non-extraction protocols for correction of Class I malocclusion provide similar satisfactory results; however, the extraction protocol increases the overall treatment duration. Orthodontic treatment is more efficient in cases with high initial malocclusion severity treated with a non-extraction protocol. .

INTRODUÇÃO: o objetivo desse estudo retrospectivo foi comparar os resultados oclusais, o tempo e o grau de eficiência do tratamento da má oclusão de Classe I realizado com e sem extrações em pacientes que apresentavam diferentes tipos de severidade oclusal inicial. MÉTODOS: a amostra foi composta pelas documentações de 111 pacientes, divididas em dois grupos: Grupo 1 (n = 65), com idade inicial média de 13,82 anos, tratados com extrações; Grupo 2 (n = 46), com idade inicial média de 14,01 anos, tratados sem extrações. De cada grupo, foram obtidos dois subgrupos (1A, 1B, 2A e 2B) com severidades oclusais diferentes (alta e baixa), de acordo aos valores iniciais do índice PAR. A avaliação da compatibilidade foi realizada por meio do teste qui-quadrado e do teste t. Os subgrupos foram comparados por meio da análise de variância (ANOVA) e foi realizada a análise de regressão linear múltipla para avaliação das variáveis que poderiam estar relacionadas com o tempo e com a eficiência do tratamento. RESULTADOS: a severidade oclusal inicial esteve diretamente relacionada à quantidade de sua correção e, consequentemente, à obtenção de um maior índice de eficiência; por outro lado, a utilização do protocolo de extrações de pré-molares mostrou uma relação direta com o tempo de tratamento e inversa com a eficiência do tratamento. CONCLUSÃO: no tratamento da má oclusão de Classe I, podem ser obtidos resultados oclusais satisfatórios com uma maior quantidade de correção das alterações oclusais nos casos com maior severidade inicial, e um maior tempo de tratamento quando o tratamento envolve extrações dentárias. .

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.

Extraction decision and identification of treatment predictors in Class I malocclusions.

BACKGROUND: The extraction rate in orthodontics varies throughout the years. While the extraction decision is easily made or excluded in clear-cut cases, it still remains controversial what makes an orthodontist decide to extract in borderline cases. The aim of this retrospective study was to identify the percentage of extraction cases in a large group of Class I malocclusions and to clarify which variables contributed most to the extraction decision. METHODS: The sample consisted of 542 randomly selected records of Class I patients treated in a university graduate program and in five private orthodontic offices. Of these patients, 331 were female and 211 male. The mean age was 14.55 (standard deviation (SD) 5.36) for the non-extraction group and 14.52 (SD 4.86) for the extraction group. The extensive series of 32 linear and angular measurements derived from the cephalometric analysis and the dental casts, along with the variables of age and gender, fueled a stepwise discriminant analysis. RESULTS: The percentage of the patients treated with four first premolar extractions was 26.8%. The results showed that the variables of lower crowding, lower lip to E-plane, upper crowding, and overjet accounted most for the decision to extract at a very significant level (Sig. 0.000). The discriminant analysis assigned a classification power of 83.9% to the predictive model (p<0.0001). Fisher's linear discriminant functions provided a mathematical model, according to which any case can be classified into the adequate treatment group. CONCLUSIONS: In a large contemporary sample of 542 Class I patients, the extraction rate was 26.8%. The most important measurements when the orthodontist decides extractions in Class I cases are lower crowding, lower lip to E-plane, upper crowding, and overjet. In clinical orthodontic practice, the findings facilitate treatment by providing evidence-based treatment predictors for Class I malocclusions.

Magnetic resonance imaging-verified temporomandibular joint disk displacement in relation to sagittal and vertical jaw deformities.

This retrospective study was designed to analyze the relationships between temporomandibular joint (TMJ) disk displacement and skeletal deformities in orthodontic patients. Subjects consisted of 460 adult patients. Before treatment, lateral cephalograms and TMJ magnetic resonance imaging (MRI) were recorded. Subjects were divided into six groups based on TMJ MRI according to increasing severity of TMJ disk displacement, in the following order: bilateral normal TMJs, unilateral disk displacement with reduction (DDR) and contralateral normal, bilateral DDR, unilateral disk displacement without reduction (DDNR) and contralateral normal, unilateral DDR and contralateral DDNR, and bilateral DDNR. Subjects were subdivided sagittally into skeletal Class I, II, and III deformities based on the ANB (point A, nasion, point B) angle and subdivided vertically into hypodivergent, normodivergent, and hyperdivergent deformities based on the facial height ratio. Linear trends between severity of TMJ disk displacement and sagittal or vertical deformities were analyzed by Cochran-Mantel-Haenszel test. The severity of TMJ disk displacement increased as the sagittal skeletal classification changed from skeletal Class III to skeletal Class II and the vertical skeletal classification changed from hypodivergent to hyperdivergent. There were no significant differences in the linear trend of TMJ disk displacement severity between the sexes according to the skeletal deformities. This study suggests that subjects with skeletal Class II and/or hyperdivergent deformities have a high possibility of severe TMJ disk displacement, regardless of sex.

Mixed longitudinal evaluation of masticatory performance in children 6 to 17 years of age.

INTRODUCTION: The purposes of this study were to determine (1) how masticatory performance changes with age, (2) whether masticatory performance differs between the sexes, and (3) whether patterns of masticatory performance differ among subjects with various types of malocclusion. METHODS: A total of 450 children and adolescents (244 boys, 206 girls) were assigned to 4 age cohorts (ages 6, 9, 12, and 15 years) and followed for 3 consecutive years. The subjects were selected based on having about equal numbers of boys and girls, and about equal numbers of subjects with normal occlusion and Class I and Class II malocclusions. Masticatory performance was assessed by using the artificial food CutterSil (Heraeus Kulze, South Bend, Ind). The peer assessment rating index was used to quantify the severity of the malocclusions. RESULTS: Median particle size (MPS) decreased significantly from 6 to 17 years of age. There were no statistically significant differences in MPS between the 3 occlusal groups, but there were significant sex differences, with girls having smaller MPS than boys. Multilevel analysis showed greater decreases in MPS between 6 and 9 years, and after 12 years of age, than between 9 and 12 years of age. There were no significant correlations between MPS and the weighted peer assessment rating index. MPS showed significant intercorrelations between measures of MPS obtained at years 1, 2, and 3, with correlations tending to be highest for the oldest age cohort. CONCLUSIONS: Masticatory performance improves with age, and the changes appear to be influenced by the loss of the deciduous teeth during the late mixed dentition phase of dental development. Although there are limited sex differences in masticatory performance among subjects 6 to 17 years of age, mild forms of Class I and Class II malocclusions have little or no effect on masticatory performance.

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.

Evaluation of CBCT digital models and traditional models using the Little's Index.

OBJECTIVE: To determine if measurements obtained from digital models from cone beam computed tomography (CBCT) images were comparable to the traditional method of digital study models by impressions. MATERIALS AND METHODS: Digital models of 30 subjects were used. InVivoDental (Anatomage, San Jose, Calif) software was used to analyze CBCT scans taken by a Galileos cone beam scanner (Sirona, Charlotte, NC) with a field of view of 15 x 15 x 15 cm(3) and a voxel resolution of 0.125 mm. OrthoCAD (Cadent, Fairview, NJ) software was used to analyze impression scans of patients at different stages of orthodontic treatment. Impressions were taken using alginate and were mailed to OrthoCAD for digital conversion. The scans were then electronically returned in digital format for analysis. RESULTS: The maxillary mean scores for the Little's Index were 9.65 mm for digital models and 8.87 mm for InVivoDental models, respectively. The mandibular mean scores for the Little's Index were 6.41 mm for digital models and 6.27 mm for InVivoDental models, respectively. The mean overjet measurements were 3.32 mm for digital models and 3.52 mm for InVivoDental models, respectively. The overbite measurements were 2.29 mm for digital models and 2.26 mm for InVivoDental models, respectively. The paired t-test showed no statistical significance between the differences in all measurements. CONCLUSIONS: CBCT digital models are as accurate as OrthoCAD digital models in making linear measurements for overjet, overbite, and crowding measurements.

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.

Mal oclusiones clase I / Class I malocclusions

El ejercicio de la ortodoncia incluye diagnóstico, prevención, intercepción y tratamiento de todas las formas clínicas de maloclusión y anomalías óseas circundantes; además el diseño, aplicación y control de la aparatología terapéutica; cuidado, guía de la dentición y estructuras de soporte con el fin de obtener manteniendo una relaciones dentoesqueleticas óptimas en equilibrio funcional - estético con las estructuras craneofaciales. El objetivo de este trabajo es describir la maloclusión clase I, para transmitir estos conocimientos a todos los profesionales relacionado al área de ortodoncia.

Contribución de la rotación del plano oclusal a la corrección anteroposterior. ¿Cambia el plano oclusal con nuestros tratamientos? Análisis de 100 casos / The contribution of oclusal plane rotation to correct saggital maloclusions. Does the oclusal plane change with our treatments? Analysis of 100 cases

El objetivo de este artículo es investigar si la rotación del plano oclusal ayuda a corregir las maloclusiones dentarias en sentido anteroposterior. Para ello, se analizó una muestra de 100 pacientes (de entre 7 y 13 años) tratados con resultados satisfactorios en el posgrado de ortodoncia del Hospital San Rafael de Madrid. Se dividieron en 3 grupos, en función de si presentaban una maloclusión clase I, II o III. En cada paciente se midió el cambio que pesentaba la inclinación del plano oclusal funcional desde el inicio hasta el final del tratamiento y se emlearon la convexidad y el Wits como medidas anteroposteriores, para relacionar la clase dentaria con la rotación del plano oclusal. Después del análisis de los resultados, se vio que en las clases I y II el plano oclusal siguió una rotación antihoraria. El cambio en el Wits fue mínimo y la convexidad disminuyó lo esperado que se produjera como consecuencia del crecimiento. En las clases III, fue muy evidente la rotación antihoraria, lo cual colaboró a la mejora del Wits haciéndose más positivo. Las conclusiones a las que se han llegado son que a pesar de las diferentes mecánicas de tratamiento, la rotación del plano oclusal ha seguido la evolución normal esperada con el crecimiento, incluso en las clases II; que el grado de rotación ha sido mayor que el esperado con el crecimiento, especialmente en las clases III; que la rotación del plano oclusal funcional no ha contribuido a la corrección de la clase II, y que la rotación del plano oclusal únicamente ha contribuido de modo significativo a la corrección de la clase III

The aim of this retrospective analysis is to study if the rotation of the oclusal plane helps to correct the dental saggital maloclusions. A sample of 100 patiens (between 7 and 13 years old) who were treated successfully during the orthodontics Postgrade at Saint Raphael Hospital in Madrid, was chosen. The subjects were classified into 3 groups, based on their maloclussion type I, II or III. We have measured the changement of inclination of the functional oclusal plane, for each patient, from the begining to the end of treatment. We have used the convexity and the Wits as saggital measures to relate the dental class with the rotation of oclusal plane. The results revealed that in class I and II the oclusal plane followed a counter clockwise rotation. The change in Wits was minimal and convexity decreased as we expected in growing patients. In class III, it have been observed and evident counter clockwise rotation, wich helps to improve Wits, therefore becoming more possitive. There are four final conclusions that have been achieved: 1) in spite of different treatment, the oclussal plane have followed the normal rotation during growth, even in class II; 2) the degree of rotation has been bigger than we expected during growth, specially in class III; 3) the rotation of functional oclusal plane hasn´t help to correct the class II; and 4) the rotation of oclusal plane has only help significantly to correct the class III

Perceived relative attractiveness of facial profiles with varying degrees of skeletal anomalies.

OBJECTIVE: The objective of this study was to answer the following questions: Are profiles of Class I patients perceived as more attractive than profiles of Class II or Class III patients in Germany today? How pronounced must a skeletal malocclusion be to be perceived as less attractive? Are there differences in perception between dentists and laypersons? MATERIAL AND METHOD: For the present study we examined seven patients with skeletal Class I, orthognathic maxillae and mandibles, and straight average faces (ideal biometric face as defined by A. M. Schwarz). Using the Onyx Ceph software, their profile lines were modified to reflect three different Class II profile variants and three different Class III profile variants. The 49 profiles thus obtained were assigned to two groups. Group 1 comprised the seven straight average faces and the first part of the retrognathic and prognathic profile variants. Group 2 comprised the same seven straight average faces and the remaining retrognathic and prognathic profile variants. Both groups of faces were scored by 130 laypersons and 126 dentists. RESULTS: Both groups of observers perceived the seven straight average faces similarly both in the first and second (subsequent) scoring rounds. The straight average face was perceived as most attractive by laypersons (mean, 5.48; 95% confidence interval (CI:) 5.33-5.60) and dentists (mean, 5.44; 95% CI, 5.28-5.50) alike, followed by the mildest variant of the retrognathic face (laypersons, mean, 4.85; 95% CI, 4.68-5.01; dentists, mean, 4.98; 95% CI, 4.81-5.10). Dentists differentiated more clearly by degree of skeletal malocclusion than did laypersons. Both groups alike perceived the extreme variant of the prognathic and retrognathic profile lines as the least attractive. Grouping the subjects by gender yielded only minor differences in perception. CONCLUSION: The straight average face is perceived as most attractive by representative German populations today. Dentists make clearer gradual distinctions in their perceptions than do laypersons.

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.

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.

Unilateral Angle II in functional lateralities.

The aim of this study was to explore unilateral Angle II-type malocclusion prevalences in functionally true right-sided (TRS) and non-right-sided (NRS) children having one or more left-sided functions (eye, hand, foot). A half cusp sagittal relationship of the upper and lower M1 and Dm2 was determined on dental casts of 1423 young American black and white children in a cross-sectional sample with the mean age of 8.5 years (range 6-12 years). Hand, foot and eye preferences were recorded at the age of 4 years during the Collaborative Perinatal Study. The prevalences of symmetric bilateral Angle I and II and asymmetric unilateral Angle II right and Angle II left cases were compared between TRS and NRS children using Chi-square analysis. In general, unilateral Angle II right occurred in 9 per cent of the population and Angle II left in 6.5 per cent. In moderate non-right sideness (two-thirds of left dominant functions), these proportions were 17 and 3 per cent, respectively, and in true right sidedness 8 and 6 per cent, respectively. TRS subjects were more symmetric (bilateral Angle I or II in 85 per cent of cases) than NRS children (80 per cent), and the differences were statistically significant (P < 0.02). These results highlight the anatomical relationships of structures supporting the occlusion and the symmetry/asymmetry of the neurocranium, cranial base, masticatory apparatus, and probably also the sidedness and the growth-stimulating effect of lateralized jaw function. Based on the results and considering earlier observations on brain asymmetry in functional lateralities, it can be hypothesized that a normal symmetric sagittal occlusal relationship is based on unilateral sagittal compensatory growth to maintain optimal bite, challenging early preventive orthodontic treatment in suspect unilateral Angle II cases.

The pattern of malocclusion among orthodontic patients seen in Dental Centre, University College Hospital, Ibadan, Nigeria.

The aim of this study was to analyse the malocclusion pattern among patients who presented for treatment in the Orthodontic Unit of the Dental Centre, University College Hospital, Ibadan, as baseline data for proper treatment planning, teaching and further research. A total of 289 subjects aged 5-34 years with mean age of 10.6 +/- 1.5 (S.D.) years were seen. Angle's classification of molar relationships among those seen is as follows: class I - 76.5%, Class II - 15.5% and Class III - 8.0%. There was increased overjet in 16.2% of the patients, reduced overjet in 0.7% while 2.1% had reversed overjet. Other occlusal abnormalities included: increased overbite (3.8%), reduced overbite (1.4%); anterior open bite (5.2%; crossbite (8.4%) and scissorsbite (0.6%). Crowding, spacing and retained primary incisors constituted 29.7%, 1.4% and 40.1%, respectively. Delayed eruption of canine (1.0%), Bimaxillary protrusion (0.7%), incompetent lips (0.7%), supernumerary teeth (0.7%) malformed tooth (0.3%), mandibular deviation on closure (1.0%) and oral habits (4.5%) were other forms of malocclusion diagnosed. Males were found to have significantly more of classes II and III molar relationships than females (P < 0.05). Occurrence of retained primary teeth as well as overjet deviations from normal were significantly higher in females (P < 0.05). No significant sex differences were found in the other occlusal disorders (P > 0.05): The findings were comparable with previous epidemiological surveys in other parts of the country.