Métodos de evaluación de la Dimensión Vertical Oclusal / Methods of evaluation of the Occlusal Vertical Dimension

RESUMEN: Antecedentes: La evaluación de la Dimensión Vertical Oclusal, es una fase importante en el diagnóstico y planificación del tratamiento que determina las relaciones estéticas y funcionales entre los maxilares. Objetivo: Conocer los métodos que ayuden a determinarla, ventajas y desventajas de cada uno, y los parámetros para reestablecerla. Materiales y Métodos: Se recopiló información científica desde las bases electrónicas Medline/Pubmed, EBSCO y Schoolar Google desde Enero del 2010, hasta Marzo del 2016 tanto en Inglés y Español, utilizando las palabras Dimensión Vertical Oclusal, Altura Facial Inferior y Espacio de Inoclusión Fisiológica, se leyeron los títulos y resúmenes para descartar los artículos no relacionados, eliminando los repetidos. Resultados y Discusión: La relación proporcional entre los segmentos de la cara varían de acuerdo a los estudios, de estos, las mediciones antropométricas presentan el mayor número de discrepancias, y sus resultados no pueden ser aplicados a todos los individuos. Conclusiones: no hay un método único que determine con exactitud la Dimensión Vertical Oclusal, ni evidencia científica que respalde la asociación de Trastornos Témporo Mandibulares con variaciones en la misma, incrementos de 5mm son predecibles y aunque pueden manifestar incomodidades iniciales a los pacientes, son auto limitante y remiten en pocos días.

ABSTRACT Background: The evaluation of the Occlusal Vertical Dimension is an important phase in the diagnosis and treatment planning that determines the aesthetic and functional relationships between the jaws. Objective: To know the methods that help to determine it, the advantages and disadvantages of each one, and the parameters to reestablish it. Materials and Methods: Scientific information was collected from the electronic databases Medline / Pubmed, EBSCO and Schoolar Google from January 2010 to March 2016 in both English and Spanish, using the words Occlusal Vertical Density, Lower Facial Height and Physiological Inoculation Space, Titles and abstracts were read to discard unrelated articles, eliminating repeated ones. Results and Discussion: The proportional relationship between the segments of the face varies according tothe studies; out of these, the anthropometric measurements present the greatest number of discrepancies, and their results can not be applied to all individuals. Conclusions: There is no single method that accurately determines the occlusal vertical dimension, nor scientific evidence supporting the association of temporomandibular disorders with variations in it; increments of 5mm are predictable and although they may cause initial discomforts to patients, they are self-limiting and diminish in a few days.

Adult Stature Reconstruction From Cephalo-facial Dimension In Indian Females

Aim: To identify the Stature from the cephalo-facial dimension (facial height) in Indian females.Materials and Methods: A stadiometer was used to measure the stature, and the facial height was taken byutilizing a vernier caliper, in 43 female medical students. To know about the significance and correlation, thedata were analysed statistically.Results: Mean stature and the mean facial height were found to be 158.93±11.06 cm and 10.39±0.83 cm respectively.P value was less than 0.001 and Pearson’s coefficient obtained was 0.93. Hence, there is found to be a significantpositive correlation between stature and facial height in Indian females.Conclusion: Estimation of stature from the facial height could be performed where only unknown head and faceare brought for anthropometric examinations.

Effect of extraction versus non-extraction orthodontic treatment on anterior facial height in class II division 1 malocclusion.

Background: Extraction of all 1st premolars in the orthodontic treatment of Class II div 1 malocclusion has been associated with a decrease in vertical dimension of occlusion thus predisposing the patient to TMJ disorders. Objectives: To evaluate the vertical changes occurring in patients having class II div 1 malocclusion, treated orthodontically with 1st premolar extractions & compare these changes with those occurring in patients treated orthodontically without extractions. Method: Pre-treatment & Post-treatment Lateral Cephalogram radiograph of 11 patients having CL-II div1 malocclusion treated without extraction and 16 patients treated with the extraction of all 1st premolars were analyzed and compared to observe the changes in the anterior facial height. Result: the orthodontic treatment of Cl-II div 1 malocclusion cases treated with a non-extraction approach leads to a statistically significant increase in the anterior facial height due to the downward & backward rotation of the mandible. The cases treated with the extraction of all 1st premolars also show the statically significant increase in the anterior facial height but this increase was less than that observed for the non-extraction group. Conclusion: this study does not support the theory that the first premolar extractions reduce the vertical dimension of occlusion and predispose the extraction patients to TMJ disorders.

Determinación del biotipo facial basado en características fenotípicas a través del modelo de ecuaciones estructurales: estuDio sobre tres etnias / Determining facial biotype based upon phenotypic features through structural equation modeling: a study of three ethnic groups

Introducción: el conjunto de características fenotípicas se pueden agrupar y además determinar el peso individual y colectivo que tienen a la hora de definir un biotipo. El modelo de ecuaciones estructurales (MES) se basa en relaciones causales en las que el cambio de una variable se supone que produce un cambio en otras variables. Con este modelo se validaron las relaciones causales a partir de diferentes tipos de variables mediadoras: fuerza de mordida, medidas transversales, arcos dentales, anchura bicigomática y altura morfológica de la cara. Métodos: el estudio incluyó 197 preadolescentes entre 12 y 14 años en condiciones de neutroclusion dental. El 33% mestizos, 35% afrodescendiente y 32% indígenas. El modelo hipotético fue puesto a prueba estadísticamente a través del modelo de ecuaciones estructurales. Resultados: existe un buen ajuste del modelo a los datos puesto que los indicadores de bondad de ajuste como el RMSEA = 0,078, la magnitud del índice RMR = 0,061 y el CIF = 0,988 estuvieron en el umbral esperado. Los parámetros fueron significativos, al nivel del 5%, a excepción del índice facial con la fuerza de mordida. Las cargas factoriales oscilan entre 0,55 y 0,92 y una carga factorial negativa entre el índice facial y las medidas transversales del arco dental (-0,60). Conclusión: el modelo evidencia que la variable latente que más se correlaciona con el biotipo facial es la fuerza de mordida (0,82), seguida de la relación con los arcos dentales (0,73), siendo esta una correlación moderada.

Introduction: the various phenotypic characteristics may be grouped; also, their individual and collective influence may be determined when defining a biotype. Structural equation modeling (SEM) is based on causal relations so that the change in a variable is supposed to produce a change in another variable. This model was used to validate causal relations using different types of mediating variables: masticatory force, transverse measures, dental arches, bizygomatic width, and morphological face height. Methods: this study included 197 preteens between 12 and 14 years of age with dental neutroclusion, distributed like this: 33% mestizos, 35% of African descent, and 32% indigenous. The hypothetical model was statistically tested through structural equation modeling. Results: the model is well fitted to the data since goodness of fit indicators such as RMSEA = 0.078, RMR index magnitude = 0.061, and CIF = 0.988 were within the expected limits. The parameters were significant to a 5%, except for facial index with masticatory force. Factor loads ranged from 0.55 to 0.92 and negative factor loads between the facial index and dental arch transverse measures (–0.60). Conclusion: this model shows that the variable that best correlates with facial biotype is masticatory force (0.82), followed by dental arches relation (0.73), this being a moderate correlation.

Avaliação da proporção facial vertical: relação entre as alturas tegumentar e esquelética / Evaluation of facial proportions in the vertical plane to investigate the relationship between skeletal and soft tissue dimensions

OBJETIVO: determinar a relação entre as alturas faciais obtidas na avaliação do tegumento e do esqueleto subjacente, na análise da proporção facial vertical, na região anterior. MÉTODOS: foram utilizadas 24 radiografias cefalométricas de perfil e 48 fotografias da face, sendo 24 de perfil e 24 frontais, pertencentes a 24 indivíduos brasileiros, 7 do sexo masculino e 17 do feminino, na faixa etária de 19 a 38 anos. Foram realizados traçados cefalométricos e, sobre esses, obtidas medidas lineares, segundo as análises preconizadas por Schudy, Wylie e Johnson e Thompson e Brodie. Sobre as fotografias faciais, foram demarcados os pontos glabela, subnasal e mento, o que permitiu a medição das distâncias lineares entre os mesmos. Os dados obtidos foram, então, tratados estatisticamente. RESULTADOS E CONCLUSÕES: encontrou-se correlação positiva entre as avaliações do tegumento e do esqueleto subjacente, com base nas análises de Schudy (r=0,619, p<0,001), Wylie e Johnson (r=0,595, p<0,002) e Thompson e Brodie (r=0,630, p<0,001), embora, individualmente, algumas discordâncias tenham sido identificadas, devido à variabilidade em espessura nos tecidos moles.

OBJECTIVE: To determine the relationship between facial heights by evaluating the soft tissues and underlying skeleton and by analyzing vertical facial proportions in the anterior region. METHODS: The study used 24 lateral cephalometric x-rays and 48 photographs of the face, 24 in profile view and 24 in front view, belonging to 24 Brazilian individuals, 7 men and 17 women whose ages ranged from 19 to 38 years. Cephalometric tracings were performed and linear measurements obtained according to the analyses suggested by Schudy, Wylie & Johnson, and Thompson & Brodie. The anatomical landmarks glabella, subnasal and menton were identified on the photographs, which allowed the measurement of linear distances between these points. The data were then statistically analyzed. RESULTS AND CONCLUSIONS: A positive correlation was found between evaluations of the soft tissues and underlying skeleton based on the analyses advanced by Schudy (r=0.619, p<0.001), Wylie & Johnson (r=0.595, p<0.002) and Thompson & Brodie (r=0.630, p<0.001), although, individually, some discrepancies were identified due to variability in soft tissue thickness.

Características craneofaciales en pacientes con desgaste dentario severo / Craniofacial characteristics in patients with severe toothwear

Introducción: con la finalidad de contrastar la hipótesis nula “no existen diferencias significativas en lascaracterísticas arquitecturales y estructurales craneofaciales entre individuos con y sin desgaste dentario” se realizó un estudio analítico, no experimental de casos y controles en pacientes que consultaron por tratamiento prostodóncico u ortodóncico. Métodos: la muestra quedó conformada por 26 pacientes con desgate dentario severo (estudio) y 52 pacientes sin desgaste dentario (control).El grupo control se obtuvo por pareamiento según sexo, rango de edad y ángulo de la base de cráneo. Todos ellos poseían estabilidad oclusal y no presentaban tratamiento ortodóncico previo, procedimientos quirúrgicos maxilofaciales ni patologías de crecimiento y desarrollo. Se utilizó un cefalograma específicamente diseñado que incluyó los parámetros arquitecturales y estructurales delanálisis de Delaire. Para el análisis de los datos fueron utilizados el t Test y el Chi cuadrado dependiendo de la naturaleza de los datos. Resultados: diferencias significativas fueron encontradas particularmente a nivel del hueso basal maxilar y mandibular y en la posición del plano oclusal real respecto al plano oclusal teórico. Conclusiones: se concluyó que en pacientes con desgaste dentario severo, se produce una modificación del hueso basal y mandibular por remodelación del proceso dentoalveolar que resulta en una rotación craneal del plano oclusal. Se observa aparente estabilidad de la altura facial y del ángulo mandibular a pesar del cambio obvio de la posición del plano oclusal.

Introduction: in order to test the null hypothesis “there are no significant differences in the craniofacial architectural and structural characteristics among individuals with and without severe tooth wear”, a non experimental analytic case controlstudy was carried out with patients who consulted for prosthodontic or orthodontic treatment. Methods: 78 patients between 22 and 55 years of age participated. The experimental group consisted of 26 patients between 29 and 55 years of age (9 women and17 men). The control group consisted of 52 patients between 22 and 50 years of age (18 women and 34 men) matched by gender —age range and posterior cranium base angle. All of them had occlusal stability, without previous orthodontic treatment, surgeryor growth and development alterations. The measuring instrument was a specifically designed cephalogram which included the architectural and structural parameters from Delaire’s Analysis, combined with some extra radiographic points defined by the authors for this particular study. The parameters under investigation were different cranial structural relationships includingocclusal plane position. Statistical analysis using t-test, Chi square test and Pearson’s correlation test were carried out depending of the nature of the data. Results: significant differences were particularly found on maxillary and mandibular basal bone and on the position of the actual occlusal plane with respect to the theoretical plane. Conclusions: it was concluded that in patients with severe tooth wear, a modification of the maxillary and mandibular basal bone could have taken place with remodelling of the dental alveolar process resulting in a cranial rotation of the occlusal plane. An apparent stability of the facial height and the mandibular angle was observed in spite of the obvious change in the position of the occlusal plane.

The relationship between upper airway width and facial growth changes in orthodontic treatment of growing children / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate how airway changes influence facial growth during puberty in Korean children. METHODS: Thirty-six patients aged 9 to 11 (mean age: 10.7 years) were selected. Cephalograms and hand-wrist x-rays were taken at pre-treatment (T1) and post-treatment (T2). The sample was divided into narrow (5.2 - 8.6 mm, AW-Narrow), medium (8.9 - 11.5 mm, AW-Medium), and wide (11.7 - 16.0 mm, AW-Wide) groups according to the airway width at T1. Cephalometric measurements at T1, T2 and growth from T1 to T2 were compared between groups. RESULTS: The degree of increase in airway size in each group was 4.55 mm, 3.84 mm and 1.94 mm in the AW-Narrow, AW-Medium, and AW-Wide groups, respectively. Moreover, the differences were statistically significant. The significant smallest posterior facial height was found in the AW-Narrow group at T1. For the growth values from T1 to T2, the AW-Narrow group showed significantly larger values of PFH/AFH, facial axis, ANS (T1 - T2), and Gn (T1 - T2) than the AW-Medium group. CONCLUSIONS: The compensational changes in the airway width and facial growth were found in the narrow group. Surgical approach of the airway to prevent unfavorable facial growth in these years of age should be carried out, but with careful deliberation because these problems may be improved naturally.

Análise correlativa entre medidas esqueléticas verticais em indivíduos com oclusão excelente e má oclusão / Correlative analysis between vertical measurements in individuals with excellent occlusion and malocclusion

INTRODUÇÃO: avaliar as proporções verticais faciais é um dos parâmetros mais importantes a ser utilizado pelo ortodontista no planejamento da terapia apropriada. Porém, não é raro que, quando se avaliam medidas isoladamente, tenha-se uma idéia errônea do que a face do paciente apresenta em termos de padrão vertical. OBJETIVOS: o presente trabalho realizou diferentes correlações entre a ângulo do plano mandibular (GoGn-SN), o índice de altura facial (IAF) e a sobremordida, avaliando a resposta dessas correlações quanto ao padrão citado na literatura, além de identificar possíveis fatores que, eventualmente, levassem essas medidas a um comportamento fora desse padrão. METODOLOGIA: o estudo foi realizado em radiografias cefalométricas de perfil entre dois grupos de indivíduos brasileiros - um portador de oclusão excelente e outro de má oclusão - atendidos no Curso de Especialização em Ortodontia e Ortopedia Facial da Faculdade de Odontologia da Universidade Federal da Bahia. RESULTADOS: as medidas esqueléticas GoGn-SN e IAF apresentaram forte correlação entre si. A sobremordida, entretanto, não apresentou correlação com essas medidas no grupo com oclusão excelente e demonstrou fraca correlação naquele com má oclusão. Uma correlação coerente com o padrão citado na literatura foi encontrada em 35 por cento e 31 por cento dos indivíduos dos grupos com oclusão excelente e má oclusão, respectivamente. Os indivíduos restantes apresentaram variações na altura dentoalveolar dos incisivos, compensando as displasias verticais. No grupo com oclusão excelente, esse fator se somou às compensações na região de molares. CONCLUSÕES: os resultados encontrados indicam que a maior parte dos grupos apresentou um comportamento diferente do padrão citado na literatura, quando as três medidas foram correlacionadas simultaneamente.

INTRODUCTION: The evaluation of facial vertical proportions is one of the most important features considered by the orthodontist when choosing the appropriate therapy. Meanwhile, when vertical measurements are analyzed separately, one could have an unreliable idea of what the patient's face presents considering vertical development. AIM: The purpose of this research was to perform a correlative analysis between the vertical cephalometric measurements: mandibular plane angle (GoGn-SN), facial height index (FHI) and overbite; to evaluate if the simultaneous correlation of these measurements is in agreement with the results cited in the literature; and to identify the possible factors which could, eventually, lead to different results from those expected. METHODS: This study was performed through cephalometric x-rays obtained from randomly chosen individuals with excellent occlusion and malocclusion, selected from the Orthodontics Program of the Federal University of Bahia. RESULTS: The skeletal measurements GoGn-SN and FHI showed strong correlation. The overbite level did not showed correlation with these measurements in the excellent occlusion group, and showed weak correlation in the malocclusion group. Only 35 percent of the individuals with excellent occlusion showed an expected correlation between the three measurements, while this percentage was of 31 percent in the malocclusion group. The remaining individuals showed variations in the incisor dentoalveolar heights as a major factor in compensating the vertical dysplasia, and in the excellent occlusion group it was also found compensations in the molars area. CONCLUSIONS: The results indicates that the most part of the groups presented a correlation between the three vertical measurements different from the pattern related in the literature.

Changes in Tongue Position, Airway Width, Gonial Angle, Lower Facial Height after Bilateral Sagittal Split Ramus Osteotomy in Mandibular Prognathic Patients

INTRODUCTION: In patients with mandibular prognathism, Bilateral Sagittal Split Ramus Osteotomy(BSSRO) combined with orthodontic treatment reduces oral volume and influences tongue and other surrounding tissues. Purpose of this study was to analyze post-operative tongue position and airway dimension, as well as mandibular changes in vertical, horizontal, and angular dimensions. MATERIALS AND METHODS: Height of dorsum of tongue, width of airway, gonial angle and lower facial height of mandibular prognathic patients who visited Kangdong Sacred Heart Hospital from Jan. 2001 to Dec. 2006 were anaylzed via pre-operative and post-operative cephalograms. T-test was used to compare pre-operative and post-operative measurements. Also, correlations among pre-operative measurements of the patients were analyzed. RESULTS AND CONCLUSION: A significant correlation was shown between ANS-Xi-PM area and location of dorsum of tongue in pre-operative patients. A significant superior movement of tongue and decrease of airway width was observed in post-operative patients. Also the upper gonial angle decreased significantly.

Treatment effect of face mask therapy for Class III malocclusion patients according to low facial morphology / 대한치과교정학회지

OBJECTIVE: Improvements in jaw relationship through clockwise rotation of the mandible may be desirable in some Class III patients with short low facial height. The aim of this study was to examine the treatment effect of face mask for Class III malocclusion patients according to their low facial morphology. METHODS: Class III patients in their pubertal growth period were divided into two groups (Group 1, high LFH; Group 2, low LFH) according to lower facial height (LFH) by Ricketts (norm, 47). Treatment changes between groups after face mask treatment was compared not only for hard tissue but also for soft tissue. RESULTS: There were no significant differences between the two groups for the skeletal and soft tissues of the maxilla. There were no significant differences between the two groups for the skeletal posterior movement of the mandible, but posterior movement of the mandibular soft tissues in group 2 was larger than group 1. There were no significant differences between the two groups for the vertical hard tissue proportion changes of the mandible, but the vertical soft tissue proportion changes of the mandible in group 2 was larger than group 1. There was a significant correlation between the sagittal hard tissue and soft tissue changes of the maxilla and mandible, but there was no significant difference in the vertical changes. CONCLUSION: The clockwise rotation of the mandible occurred from use of the face mask, and posterior movement of soft tissues of the mandible was higher in Cl III patients with low LFH than with high LFH.

Level of perception related to changes in lower facial height / 대한치과교정학회지

Understanding the level of a person's perception of changes that have occurred on the face after orthodontic treatment is critical to the process of orthodontic diagnosis and treatment planning. The purpose of this study was to determine the level of perception of profile and frontal changes in lower facial height. Forty students attending art school participated in a study evaluating the level of a participant's perception of changes in the lower facial height. Participants compared computer-graphic frontal and profile photographs with balanced proportions and photograph simulations of 1, 2, 3, and 4 mm changes in lower facial height from stomion to the chin. At least a 2 mm change in lower facial height for the profile view and 3 mm in the frontal view was needed to be perceived after orthodontic treatment. The level of a person's perception of the change in lower facial height was more sensitive in the profile view than in the frontal view, and information about facial changes given prior to evaluation enhanced the level of perception.

A Study on the mandibular setback osteotomy and reduction genioplasty in mandibular prognathism with long anterior facial height / 대한치과교정학회지

The purpose of this study was to evaluate the amount and interrelationship of hard and soft tissue changes after mandibular setback osteotomy and reduction genioplasty in mandibular prognathism with long anterior facial height. The control group (Group A) consisted of 20 patients who had severe horizontal discrepancy. They experienced presurgical orthodontic treatment and orthognathic surgery via mandibular setback. The experimental group (Group B) consisted of 20 patients who had severe horizontal and vertical discrepancy. They experienced presurgical orthodontic treatment and orthognathic surgery via mandibular setback and reduction genioplasty. The presurgical and postsurgical lateral cephalograms were valuated. The computerized statistical analysis was carried on with EXCEL 97 program. The results were as follows : 1. The correlation of hard and soft tissue horizontal changes in lower 2/3 of lower anterior facial height were high for both groups. The correlation coefficients of hard tissue changes and Ls, Stm, Li changes in group B were moderately higher than Group A. 2. The correlation of hard and soft tissue vertical changes in Group B were lower than Group A. (except for pointB-Ils, Me-Me') 3. The ratio for soft tissue to Pog in Group B was lower than Group A. The ratios of hard and soft tissue vertical changes were 32% at Ils, 54% at Pog', and 60% at Me'. 4. The ratio of lower anterior facial height to total anterior facial height was reduced for both group. But ratio of upper 1/3 of lower anterior facial height to total anterior facial height did not changed significantly in Group B. 5. Reduction genioplasty combined with mandibular setback procedure showed no change in upper one third(Sn-Stm) and significant decrease(Stm-Me') in the lower two thirds of the soft-tissue anterior lower facial height.

A study on the skeletal and dentoalveolar dimensions in relation to vertical facial patterns / 대한치과교정학회지

The purpose of this study was to investigate the variations of the skeletal and dentoalveolar dimensions in relation to vertical facial patterns. Lateral cephalogram of 200 cases (100 cases of male and 100 cases of female, average age of which was 23.2 years) were traced and some measurements of skeletal and dentoalveolar dimensions were measured. The ratio of UAFH/LAFH was employed to classify the samples into groups of excess and short lower anterior facial height. And the comparison between two groups were taken statistacally. The following results were obtained. 1. The dentoalveolar height, lower anterior facial height, lower gonial angle, and FMA in the excess-lower-anterior-facial-height group were significantly larger than those in short-lower-anterior-facial-height group. 2. The dentoalveolar height, ramus height, and Jarabak ratio in the male subjects were significantly larger than those in the female subjects. 3. The UAFH/LAFH ratio showed a significant correlation to upper, lower facial height, AUDH, PUDH, ALDH, PLDH, Lower gonial angle, FMA, and Bjok`s Sum.

Roentgenocephalometric study on facial height and occlusal plane inclination in Class II maloclusion group / 대한치과교정학회지

This study was investigated to assess the difference of facial height and occlusal plane inclination between normal occlusion group and class 11 malocclusion group. The subjects consisted of 50 normal occlusion (male 25, female 25) and 50 class II(male 25, female 25) malocclusion patients. All subjects are adult. lateral cephalogram was taken with standard method, traced, and digitized for each subjects. The computerized statiscal analysis was carried out with SPSS program. The results were as follows: 1. In class II malocclusion group, variables significant different from normal occlusion group were as follows SN-FOP, FH-BOP, MP-BOP, AB-BOP, AB-FOP, Facial plane-BOP, FP-FOP. 2. In class II malocclusion group, the posterior facial height -especially posterior lower facial height-was significantly smaller than normal occlusion group.( P < 0.05) 3. In class II malocclusion group, the angles bEStween occlusal plane and upper and lower incisor, the angle between upper molar and bisected occlusal plane we e significantly larger than those of normal occlusion group. (P < 0.05) 4. LI to Mandibular plane (mm) was a unique factor of occlusal plane position that showed significant difference in class -Il1 malocclusion group. 5. The correlation between overbite and occlusal plane inclination existed in class II malocclusion group, but the correlation didn't exist in normal occlusion group.

A cephalometric study on correlation between mandibular symphysis and craniofacial skeleton / 대한치과교정학회지

The configuration of mandibular symphysis is likely to be dependent upon the genetic predeterminants and/or compensatory adjustments onto functional demands. The interrelation of morphological distinctives of symphysis in conjunction to the craniofacial skeleton had been scarcely anecdotal, therefore, the objective was to determine the correlation of morphological modifications between the mandibular symphysis and craniofacial complex. Lateral cephalometric headfilms of 212 subjects were employed for the conventional measurements. The proportion of chin height against chin depth length was referred as chin ratio, then, Low Symphysis (IS) and High Symphysis (HS) groups were turned out by means of the chin ratio. These samples yielded 35 in LS and 35 in HS groups. The data per capita were statistically analyzed and the following results were drawn ; 1. Overall characteristics of the craniofacial skeleton in HS group manifested hyperdivergence and LS group showed hypodivergence. 2. Gonial angle increased as chin ratio increased and was highly correlated to the chin ratio. 3. The chin ratio presented high correlation to the vertical face height, especially in terms of the chin height to anterior face height and the chin depth to posterior face height. 4. The morphological configuration of chin was hardly correlated with hyoid bone position.

A study on the pattern of skeletal change following cervical headgear therapy in growing children / 대한치과교정학회지

This study was to investigate the horizontal & vertical bone change pattern when using cervical headgear in Class II malocclusion of growing children and compared the skeletal features between the group with increased lower facial height and the group without increase in lower facial height. The results are as follows; 1. Forward growth of maxilla was inhibited, downward tipping of anterior palatal plane could be seen and distal movement of maxillary first molar was observed. 2. There was relative forward movement of Mandible against the Maxillary cranial base, and relative forward movement of mandibular 1st molar against the Maxilla and vertical increase due to alveolar growth of Mandible. 3. There was significant increase in anterior and posterior facial heights but the ratio of facial height showed no significant difference. 4. The group with increased lower facial height has shorter ramus length, than the smaller palatal plane angle, and more distal movement of Maxillary 1st molar than the group without increase Ha-young Hyun.

A cephalometric study on factors affecting the FHI (facial height index) in Angle's Class II division 1 malocclusion patients / 대한치과교정학회지

Facial vertical dyscrepancies is decided on the relationship between the anterior vertical facial height and posterior vertical facial height. Thus this study was conducted to determine the factors that affect the FHI, and classify the Class II div.1, malocclusion, which success is dependent on the vertical control according to the FHI, which is the ratio of antero-inferior facial height, posterio-inferior facial height ratio, and to use this as a guideline for treatment. Angle between palatal plane and Mandibular plane were in the order of RH, ID. Thus showing that interrelated angle was more inportant than the independent angle of both, palatal plane and Mandibular plane. The tendency of Cl II div.1. Malocclusion according to FHI, showed the Low group to have Mx. protrusion, prominent development of Mn. ramus, and the Mn. body length and ant. post. position was normal. The Normo group showed slight protrusion of the Maxilla,. The development of the ramus was less than normal and the Mn. was in a slight retruded position. The High group showed the Mx. in a normal position, the development of the Mn. ramus and body was the lowest, and the Mn. was in a posterior position. In observation of the factors affecting the FHI between each groups of Cl II div.l, malocclusion; In the Low group the MP- PP angle was very small, the ID was smililar to the normal group, but the RH was very large thus the FHI was increased. In the Normo group, the PP-MP angle was normal, ID was slightly smaller than the normal group and the RH was slightly smaller than the normal group, thus maintaining a normal FHI ratio. In the High group the PP-MP angle was very large, the ID was similar to the normal group, but the RH was smaller than the normal group thus the FHI was small.

Roentgenocephalometric study on facial height and occlusal plane inclination in Class I malocclusion group / 대한치과교정학회지

This study was investigated to assess the difference of facial height and occlusal plane inclination between pre and post-treatment in Class I malocclusion group. The subjects consisted of 35 extraction patients and 30 nonextraction patients, and was subdivided into Group I(overbite4mm) in reference to overbite, and adolescent group and adult group in reference to age. Lateral cephalogram was taken with standard method, traced, and digitized for each subject. The computerized statistical analysis was carried out with SAS program. The results were as follows: 1. In both groups of extraction and nonextraction group the anterior facial height increased after orthodontic treatment, but there was no significant difference(p>0.05) between each group. 2. There was no statistical significance in change of occlusal plane inclination in adolescent group, but significant difference(p<0.05) among three subgroup in adult group. 3. In adolescent-extraction and adolescent-nonextraction group there was significant increase of anterior facial height and posterior facial height, and was superior to adult groups in posterior facial height increment. 4. In all groups upper and lower molars were uprighted to occlusal plane. This had statistically significant effect.