Treatment of anterior skeletal open-bite deformity

Evaluation of anterior open bite correction in patients treated with maxillary posterior segment intrusion using zygomatic anchorage

INTRODUCTION

This study aimed to investigate dentofacial changes in patients treated with maxillary molar intrusion with zygomatic anchors.

METHODS

The study group was composed of 19 patients with anterior open bite who had intrusion of the posterior dentoalveolar segment using an acrylic appliance supported by bilateral zygomatic miniplates. The study was carried out on lateral cephalograms of the subjects taken before treatment and after intrusion.

RESULTS

Cephalometric changes obtained with maxillary molar intrusion were statistically significant. ANB, Wits, SN-GoGn, PP-MP, ANS-Me, NA-APo, SN-OP, U1-OP, U6-NF, overjet, and overbite values were also statistically significant.

CONCLUSIONS

Posterior dentoalveolar intrusion by zygomatic anchorage was an effective method for anterior open bite treatment. Although overbite and vertical skeletal measurements changed because of posterior dentoalveolar intrusion, the soft tissue was not significantly affected.

Posterior teeth angulation in non-extraction and extraction treatment of anterior open-bite patients

Backgound

This study cephalometrically evaluated the posterior teeth angulation changes of anterior open-bite non-extraction and extraction treatment in the permanent dentition, with anterior vertical elastics.

Methods

The sample consisted of initial and final lateral headfilms of 60 patients divided into 2 groups: Group 1 consisted of 30 patients treated with non-extraction with an initial mean age of 15.26 years and treated with fixed appliances for a mean period of 2.46 years. Group 2 consisted of 30 patients treated with extractions, with an initial mean age of 14.03 years, and treated with fixed appliances for a mean period of 2.49 years. Within-group treatment changes were evaluated with paired t tests. Results were considered statistically significant at P < 0.05.

Results

The mandibular posterior teeth were significantly uprighted in both groups with both treatment protocols.

Conclusions

Correction of anterior open bite with either non-extraction or extractions with continuous archwires and vertical anterior elastics uprights the mandibular posterior teeth.

Posterior tooth angulations in patients with anterior open bite and normal occlusion

INTRODUCTION

The aim of this study was to compare the posterior tooth angulations in patients with open-bite malocclusion and normal occlusion.

METHODS

Lateral cephalometric headfilms of 45 untreated open-bite subjects were compared with the lateral headfilms of 45 subjects with normal occlusion in the permanent dentition. The groups were matched for age and sex distribution and compared with t tests.

RESULTS

The maxillary and mandibular premolars were more mesially angulated in relation to the bisected occlusal plane, and the first and second molars were significantly more distally angulated in the open-bite group in relation to the palatal and mandibular planes.

CONCLUSIONS

The maxillary and mandibular premolars were more mesially angulated in relation to the bisected occlusal plane and therefore do not compensate for the divergence of the palatal and mandibular planes as the molars do.

Chewing pattern and muscular activation in open bite patients

Different studies have indicated, in open bite patients, that masticatory muscles tend to generate a small maximum bite force and to show a reduced cross-sectional area with a lower EMG activity. The aim of this study was to evaluate the kinematics parameters of the chewing cycles and the activation of masseters and anterior temporalis muscles of patients with anterior dental open bite malocclusion. There have been no previous reports evaluating both kinematic values and EMG activity of patients with anterior open bite during chewing. Fifty-two young patients (23 boys and 29 girls; mean age±SD 11.5±1.2 and 10.2±1.6years, respectively) with anterior open bite malocclusion and 21 subjects with normal occlusion were selected for the study. Kinematics parameters and surface electromyography (EMG) were simultaneously recorded during chewing a hard bolus with a kinesiograph K7-I Myotronics-Usa. The results showed a statistically significant difference between the open bite patients and the control group for a narrower chewing pattern, a shorter total and closing duration of the chewing pattern, a lower peak of both the anterior temporalis and the masseter of the bolus side. In this study, it has been observed that open bite patients, lacking the inputs from the anterior guidance, that are considered important information for establishing the motor scheme of the chewing pattern, show narrower chewing pattern, shorter lasting chewing cycles and lower muscular activation with respect to the control group.

Características cefalométricas do Padrão Face Longa: considerando o dimorfismo sexual

OBJETIVO: o presente estudo avaliou a hipótese de variação das características cefalométricas de acordo com o gênero para portadores de Padrão Face Longa. METODOLOGIA: foi analisado um total de 73 telerradiografias em norma lateral, sendo 34 Padrão Face Longa e 39 Padrão I (grupo controle), selecionadas com base na morfologia facial, sem considerar as relações oclusais. Foram avaliados: padrão de crescimento facial, alturas faciais anteriores e posterior, relação maxilomandibular, além das relações dentárias com suas bases apicais. RESULTADOS: o grupo controle (Padrão I) apresentou dimorfismo (p<0,001) no comprimento efetivo da maxila e da mandíbula, além das alturas faciais avaliadas. Foram significantes também (p<0,05) as proporções entre as alturas faciais e as distâncias entre os incisivos e molares em relação aos planos palatino e mandibular. Para os portadores de Padrão Face Longa, as mesmas variáveis cefalométricas não mostraram diferenças significantes entre os gêneros (p>0,05), exceto os comprimentos efetivos da maxila e da mandíbula, além da altura facial anterior inferior e posterior (p<0,05). CONCLUSÕES: concluiu-se que enquanto ocorreu dimorfismo nos indivíduos Padrão I, para as estruturas influenciadas pela diferença no tamanho esquelético entre os gêneros, isso não aconteceu nos portadores de Padrão Face Longa. Essa maior similaridade entre os gêneros provavelmente ocorreu porque a deformidade, mais grave no gênero feminino, foi suficiente para anular o menor tamanho esquelético esperado para estes indivíduos.

Proposta para classificação, segundo a severidade, dos indivíduos portadores de más oclusões do Padrão Face Longa

OBJETIVO: o presente estudo teve como objetivo propor um método para classificação, segundo a severidade, dos indivíduos Padrão Face Longa, avaliando sua confiabilidade e reprodutibilidade. METODOLOGIA: foram utilizadas fotografias faciais (frontal, perfil e frontal sorrindo) de 125 crianças Padrão Face Longa (54 do gênero feminino e 71 do gênero masculino), selecionadas apenas considerando-se a morfologia facial, com idades entre 10 anos e 6 meses e 15 anos e 2 meses. As fotografias foram avaliadas, separadamente, por três examinadores, sendo reavaliadas após três semanas, em uma nova disposição aleatória. Os indivíduos foram graduados em três subtipos, de acordo com a severidade: moderado, médio e severo. Para avaliar as concordâncias intra e interexaminadores, foi utilizada a estatística Kappa (k). RESULTADOS: na avaliação intra-examinador, todos os examinadores obtiveram concordâncias substanciais, com o valor de Kappa variando de 0,64 a 0,66, havendo em todos os examinadores 80% ou mais de concordância. Quando comparadas as avaliações interexaminadores, as freqüências de concordância diminuíram, variando de 67,2% a 70,4%. A partir dos valores de Kappa, que variaram de 0,41 a 0,46, a interpretação foi considerada moderada. CONCLUSÕES: com base nesses resultados, o método foi considerado aplicável, com necessidade de complemento de informações provenientes de outros exames rotineiramente aplicados em Ortodontia. A aplicação clínica será demonstrada com intuito de evidenciar os níveis diferentes de severidade das más oclusões do Padrão Face Longa e as características do protocolo de tratamento recomendado.

Directional force treatment for an adult with Class III malocclusion and open bite

The orthodontic treatment of an adult patient with a Class III malocclusion and an anterior overbite is presented. Successful treatment required a differential diagnosis, specific planning, and careful control of the force systems to correct the disharmony in the vertical and horizontal dimensions. Fundamental to the successful treatment was the direction of the force applied to the teeth with a J-hook headgear. This directional force application made it possible to successfully correct the malocclusion without undesirable sequelae.

Características cefalométricas do padrão face longa

Este estudo determinou as características cefalométricas dos indivíduos portadores de Padrão Face Longa em comparação com indivíduos Padrão I. Um total de 73 telerradiografias em norma lateral, sendo 34 Padrão Face Longa e 39 Padrão I, foram selecionadas com base na morfologia facial, não considerando as relações oclusais e sagitais. Foram avaliados: padrão de crescimento facial, alturas faciais anteriores e posterior, relação maxilo-mandibular, além das relações dentárias com suas bases apicais. De uma forma geral, os indivíduos Padrão Face Longa apresentaram grandes desvios em relação aos indivíduos Padrão I, sendo a doença decorrente de um desequilíbrio entre os componentes verticais. Pôde-se observar que os valores das grandezas AFAT, AFAI, AFATperp, AFAIperp, 1-PP, 6-PP, 1-PM, SNB, ANB, ângulo goníaco, ângulo plano mandibular, além das proporções AFAI/AFAT e AFAIperp/AFATperp, estavam significantemente alterados para os indivíduos Padrão Face Longa. Com base nos resultados obtidos neste estudo, verificou-se que esses indivíduos caracterizavam-se pelo padrão de crescimento vertical e por um aumento da altura facial anterior inferior - conseqüentemente, da altura facial anterior total - estando a deformidade localizada abaixo do plano palatino. Foram observados ainda um retrognatismo maxilar e mandibular, além da presença de extrusão dentária anterior (superior e inferior) e póstero-superior, com os incisivos superiores bem posicionados em suas bases e os inferiores lingualizados.

Effects of vertical chincap therapy on the mandibular morphology in open-bite patients

The aim of this study was to investigate the effects of the vertical chincap on mandibular morphology and also on the dentoalveolar structures in patients with high-angle open-bite malocclusions. We examined 35 children with high-angle skeletal Class I or II open-bite malocclusions. Eighteen subjects were selected as the treatment group, and 17 were the controls. Vertical chincaps, applying 400 g on each side from beneath the anterior part of the mandibular corpus in an upward direction, were used in the treatment group for 16 hours per day over a mean period of 9 months. We studied 70 lateral cephalograms taken before and after the treatment and the control periods. The changes of 7 linear and 8 angular parameters were evaluated statistically in both groups with paired and Student t tests, respectively. Eruption of the mandibular incisors, decrease of the ramal inclination, decrease of the mandibular plane, and increase of the overbite in the treatment group compared with the control group were found to be statistically significant. Intrusion of the first molars, decrease of the gonial angle, and increase of the mandibular corpus inclination in the treatment group were contrary to the results observed in the control group; these comparisons were also found to be statistically significant. It appears that the vertical chincap is effective in treating skeletal open bite and in decreasing the gonial angle and ramus/corpus relationship.

Cephalometric evaluation of the anterior open bite treatment

The present study was aimed at evaluating the treatment changes of anterior open bite malocclusion cases treated by means of the Multiloop Edgewise Arch Wire technique, which is considered one of the more effective treatment modalities for anterior open bite malocclusions. The open bite sample was composed of 16 young adults, 4 males and 12 females. The normal occlusion sample, as a controlled sample was composed of 58 young adults who had pleasing facial profiles and normal occlusions with no experience of orthodontic or prosthodontic treatment. The normal sample was subdivided by the cephalometric vertical facial relationships. Forty adults with cephalometric vertical facial relationships within the normal range of Korean standards were classified as Normal Occlusion Group 1. Eighteen adults with an increased vertical facial relationship but with normal occlusion, were classified as Normal Occlusion Group 2. Thirty-nine reference points were digitized on each film, and the computerized cephalometric analysis was obtained with 8 skeletal, 10 dentoalveolar, 17 teeth angulations, and 4 occlusal plane measurements. Treatment changes were determined by the paired t test, and the structural differences between the four groups were tabulated by the Student's t test. The treatment changes were observed mainly in the dentoalveolar region in the upper and the lower occlusal planes, accompanied by the uprighting of the posterior teeth to the occlusal plane through the distal tipping movement of the entire dentition. After the treatment, there was a tendency for the structural feature of the open bite group to approximate those of the normal occlusion group 2. This ascertains that the treatment changes of open bite malocclusion produced by means of the multiloop edgewise arch wire technique are similar to those found in the natural dentoalveolar compensatory mechanism.

Comparison of the effects of passive posterior bite-blocks with different construction bites on the craniofacial and dentoalveolar structures

Posterior bite-blocks that are used in the early treatment of skeletal open bite, produce a forward and upward mandibular rotation by transmitting the masticatory muscle forces to the buccal dentoalveolar regions and preventing their vertical growth. Increasing the vertical dimension of the face artificially causes skeletal adaptations to occur not only in the dentoalveolar region but also in the other regions of the craniofacial complex. The affects of passive posterior bite-blocks, constructed in two different heights, were investigated for two treatment groups, in comparison to an untreated control group. Two treatment groups comprised of 25 growing patients, who had skeletal open bite and skeletal/dental Class I or Class II malocclusions, and one control group consisting of 14 growing patients were used. These groups were matched concerning their age, sex, and vertical and sagittal skeletal cephalometric and dental characteristics. Passive posterior bite-blocks of 5 and 10 mm heights were applied to the subjects of the treatment groups respectively for 18 hours per day. Untreated control subjects were observed for 7 to 9 months. The findings of this study revealed that the downward and backward mandibular rotation continued in the control group, increasing the lower facial height significantly, whereas in the treatment groups, the skeletal open bite was treated and the mandible rotated upward and forward. The increase of the height of the posterior bite-blocks had a significant effect on the anterior mandibular rotation and in the increase of the gonial angle.

The nonsurgical treatment of a Class II open bite malocclusion

This case was treated by residents in the postgraduate orthodontic program at the University of Florida under the supervision of Dr. Hocevar. A treatment regimen that he developed to increase the strength and endurance of the masticatory muscles was used. The patient performed prescribed daily clenching and chewing exercise with resilient posterior bite-blocks and wore a hard acrylic posterior biteplane the remainder of the time. It was hoped that this approach would increase the chances of treatment success and stability.

Surgical orthodontic treatment of anterior skeletal open bite using small plate internal fixation. One to five year follow-up

Thirty-eight patients with skeletal open bite were studied retrospectively to assess stability of surgical-orthodontic treatment when small plate internal fixation was used. 86% of the sample population showed stable clinical results. Follow-up was from 1-5 years. Only 1 patient experienced skeletal relapse (3%) and 5 patients (13%) dento-alveolar relapse. Fifty percent of relapses were due to transverse relapse of orthodontically expanded maxillary arches. No relapse was seen with surgically assisted orthodontic expansion or surgical expansion at the time of osteotomy. Stable results can be achieved in treating skeletal open bite when small plate internal fixation is used and proper consideration given to the cause of skeletal open bite when planning treatment.

Growth patterns in subjects with long and short faces

The purpose of this study was to assess skeletal factors associated with the development of vertical facial disproportions. Angular measurements based on longitudinal lateral cephalometric radiographs of 16 male and 16 female subjects, from the ages of 4 through 18 years, were used. Subjects were selected on the basis of lower face height (ANS-Me) as a percentage of morphologic face height (N-Me). A single x-ray photograph at age 15 for the boys and 13.5 for the girls was used to classify each subject's occlusion as either open-bite or deep-bite. Sella-nasion/palatal plane, sella-nasion/mandibular plane, sella-nasion/anatomic occlusal plane, palatal plane/mandibular plane, and cranial base angle were analyzed statistically and graphically. It was found that (1) with the exception of sella-nasion/palatal plane and cranial base angles, all angular measurements demonstrated a progressive reduction throughout development in both open bites and deep bites; (2) the palatomandibular angle discriminated between open bites and deep bites throughout the developmental phase; (3) within each sex, typologic differences were evident in all angular measurements, with the exception of cranial base and occlusal plane; and (4) the cranial base angle demonstrated clear sexual dimorphism, and its magnitude was not associated with vertical dysplasia. The progressive reduction of angles in skeletal open bite reduced or maintained the magnitude of the imbalances, while the reduction of angles accentuated the skeletal deep bite with age. The inclination of the palatal plane and its constancy suggested that downward and backward rotation of the mandible in open bite subjects is precommitted in response to dentoalveolar compensatory changes with the center of rotation at the molars. The magnitude of the mandibular plane angle is not adequate for assessment of diagnostic or prognostic predictive value in determining the pattern of growth.

Nonextraction treatment of Class II, Division 1 malocclusions

Nonextraction treatment of three different types of Class II, Division 1 malocclusions that focused on solving the imbalances of the dentofacial configuration have been presented. Diagnostic features encountered were anterior alveolar hyperplasia that required simultaneous maxillary incisor intrusion and retraction, severe mandibular crowding requiring functional alveolar arch development, and maxillary prognathism requiring distal movement of the maxilla and incisor retraction. Since many factors contribute to the makeup of various types of Class II, Division 1 malocclusions, orthodontic mechanics should address the specific needs of each patient.

The inverted L osteotomy for treatment of skeletal open-bite deformities

Numerous surgical procedures have been proposed for the correction of the skeletal open-bite deformity. Mandibular ramus procedures have not been uniformly successful due to the amount of observed relapse in both the horizontal and vertical dimensions. The authors studied 20 patients who underwent correction of an open-bite deformity using the inverted L ramus osteotomy technique. Results indicated that this procedure may have more stability in both the horizontal and vertical dimensions than previously reported ramus procedures.

Components of adult Class II open-bite malocclusion

In an effort to identify the frequency and distribution of the dental and skeletal components of adult Class II malocclusion with and without open-bite, 124 adults, half of whom had an anterior open-bite, were evaluated. Significant differences (P less than 0.05) between the open-bite and non-open-bite groups were found for the following measurements: the posterior maxilla exhibited vertical excess in the open-bite group; the maxillary occlusal plane was less steep in the open-bite group; the mandibular occlusal plane was more steep in the open-bite group; the gonial angle was higher in the open-bite group; the mandibular plane angle was higher in the open-bite group; the mandibular ramus was positioned in a more downward and backward (clockwise) location in the open-bite group; the total and lower anterior facial height were increased in the open-bite group; and the mandible was less protrusive in the open-bite group. No significant intergroup differences were noted in the cranial base, the anteroposterior position of the maxilla or of the upper and lower incisors, the palatal plane, posterior facial height, mandibular ramus height, or mandibular body length. The results of this analysis indicate that the average Class II open-bite malocclusion is characterized by aberrations in both the maxilla and the mandible. Therapy, therefore, may frequently require surgical intervention in both jaws to successfully correct this deformity.

Components of adult Class III open-bite malocclusion

In an effort to identify the frequency and differences in the dental and skeletal components of a large sample of adults with Class III malocclusion, with and without open bite, 176 subjects, one half of whom had an anterior open bite, were evaluated. These subjects were chosen by looking at the lateral cephalometric radiographs that were taken of 302 adults (128 men and 174 women) who exhibited at least an end-to-end Class III molar and canine relationship. The dental overbite was calculated for all subjects, and those with a negative overbite were placed in the open-bite (OB) group. Those with a positive overbite were placed in the non-open-bite (non-OB) group. The dental overbite was the only criterion used to define the open-bite and non-open-bite groups. The open-bite subjects were paired with a non-open-bite subject by sex, presence of presurgical orthodontic treatment, and anterior cranial base length. Eighty-eight subjects in each group (43 men and 45 women) were obtained. Various measures of craniofacial structure were calculated and analyzed by comparing the OB and non-OB groups with the paired t test. The areas that showed significant differences (p less than 0.05) between the OB and non-OB groups were as follows: the posterior maxilla exhibited vertical excess in the OB group; the maxillary occlusal plane was less steep in the OB group; the mandibular occlusal plane was more steep in the OB group; the gonial angle was higher in the OB group; the mandibular plane angle was higher in the OB group; the mandibular ramus was positioned in a more downward and backward location in the OB group; the total anterior facial height and lower facial height were increased in the OB group; the vertical height of the anterior maxilla was increased in the OB group; and the mandible was less protrusive in the OB group. No significant intergroup differences were noted in the cranial base, the anteroposterior position of the maxilla or the upper and lower incisors, the palatal plane, posterior facial height, mandibular ramus height, or mandibular body height. The results of this analysis indicate that the average Class III open-bite malocclusion is characterized by aberrations in both the maxilla and the mandible. Surgical therapy may, therefore, require intervention in both jaws to correct this deformity successfully.

Cephalometric diagnosis and surgical-orthodontic correction of apertognathia

Nineteen postadolescent white woman with uncorrected Class I molar and/or canine occlusion were compared cephalometrically to thirteen postadolescent white women with skeletal apertognathia that was later corrected by a combination of surgical procedures, the common denominator being maxillary posterior superior repositioning. The cephalometric tracings were compared statistically by evaluating the study group preoperatively, immediately postoperatively, and at a long-term follow-up appointment. The results indicate that there is a statistical difference in certain important measurements between normal persons and preoperative apertognathic patients with the deformity identified in the dentoalveolar complex of the maxilla. Posterior maxillary superior repositioning tends to correct this skeletal deformity, with postoperative measurements approaching the normal values. The correction proved to be stable over a mean follow-up period of 19 months (range, 7 to 30 months).

An epidemiologic survey of malocclusions among American Negroes and American Hispanics

The malocclusions of thirty-six Negro and fifty-six Puerto Rican orthodontic patients from a specific area were surveyed. The population was divided according to sex, age, and skeletal classification. The total Negro malocclusion sample was compared to available Negro norms for both Downs and Steiner analyses. The total Hispanic malocclusion group was compared to available Negro and Caucasian norms for the same analyses. Ranges, means, and standard deviations were developed for each measurement recorded. The comparative frequency of individual skeletal classifications was found to be remarkably similar in both groups, and the percentage of open-bites was greater in both groups than in the general population. The need to expand available material to include a Puerto Rican group is noted.