Evaluation of changes in clinical crown length of lower anterior teeth after treatment with Frankel-2's appliance.

PURPOSE: The aim of this study was to test the null hypothesis that there is no change in the lower anterior teeth's crown size when measured just after the treatment with Frankel-2's orthopedic appliance and in a long-term posttreatment follow-up. MATERIALS AND METHODS: The sample was composed of 34 plaster models belonging to 9 male and 8 female individuals, treated at the College of Health, Methodist University of São Paulo, São Bernardo do Campo, São Paulo, Brazil, with mean age of 12 years and 6 months (standard deviation [SD] =7 months) at T1 (end of the treatment with Frankel-2's function regulator), and 19 years and 8 months (SD = 7 months) at T2 (7.11 years after the end of the treatment). RESULTS: The distance from the incisal edge to the most concave portion of the gingival margin of the lower incisors and canines was measured using a digital caliper. Data analysis was carried out by means of Student's t-test and paired-t test. Among the lower anterior teeth, the teeth 31, 33, 42 and 43 showed a statistically significant increase in their crown length, whereas the teeth 32 and 41 showed no changes. CONCLUSION: It can be concluded that there is a tendency to increase the clinical crown of lower anterior teeth throughout the years after the mandibular advancement treatment by using functional devices, rejecting the null hypotheisis.

Long-term treatment effects of the FR-2 appliance: a prospective evalution 7 years post-treatment.

AIM: To examine the long-term effects induced by treatment with the function regulator (FR-2) appliance 7 years post-treatment compared with untreated class II subjects. SUBJECTS AND METHODS: The FR-2 sample was collected prospectively and comprised 17 subjects (10 boys and 7 girls, mean age 10.8 years) who were treated with the FR-2 appliance for 1.7 years and re-evaluated 7.1 years after treatment. The step-by-step mandibular advancement was performed gradually (increments up to 3-4 mm), until a 'super class I' molar relationship was obtained. The control group consisted of 17 class II subjects (9 boys and 8 girls, mean age 11.3 years) with class II malocclusion, excessive overjet, and class II molar relationship, matched to the treated group as to ages at all times, gender distribution, and stages of skeletal maturity (evaluated by the cervical vertebral maturation method). The lateral cephalograms were analysed at T1 (initial), T2 (final), and T3 (7.1 years post-treatment). The compatibility between the groups and the comparisons of their changes at T1-T2, T2-T3, and T1-T3 intervals were examined by independent sample t-tests (P < 0.05). RESULTS: FR-2 treatment provided a significant improvement in the maxillomandibular relationship due to an increase in mandibular length compared with controls, which remained stable over time. Also overjet, overbite, and molar relationship corrections demonstrated stability. Among dentoalveolar changes, only the increased mesial movement of the mandibular molars in the FR-2 group demonstrated stability. CONCLUSIONS: Correction of class II malocclusion remained stable 7 years after FR-2 treatment mainly due to the stability of the skeletal changes.

Effect of a low-level laser on bone regeneration after rapid maxillary expansion.

INTRODUCTION: In this study, we evaluated the effects of a low-level laser on bone regeneration in rapid maxillary expansion procedures. METHODS: Twenty-seven children, aged 8 to 12 years, took part in the experiment, with a mean age of 10.2 years, divided into 2 groups: the laser group (n = 14), in which rapid maxillary expansion was performed in conjunction with laser use, and the no-laser group (n = 13), with rapid maxillary expansion only. The activation protocol of the expansion screw was 1 full turn on the first day and a half turn daily until achieving overcorrection. The laser type used was a laser diode (TWIN Laser; MMOptics, São Carlos, Brazil), according to the following protocol: 780 nm wavelength, 40 mW power, and 10 J/cm(2) density at 10 points located around the midpalatal suture. The application stages were 1 (days 1-5 of activation), 2 (at screw locking, on 3 consecutive days), 3, 4, and 5 (7, 14, and 21 days after stage 2). Occlusal radiographs of the maxilla were taken with the aid of an aluminum scale ruler as a densitometry reference at different times: T1 (initial), T2 (day of locking), T3 (3-5 days after T2), T4 (30 days after T3), and T5 (60 days after T4). The radiographs were digitized and submitted to imaging software (Image Tool; UTHSCSA, San Antonio, Tex) to measure the optic density of the previously selected areas. To perform the statistical test, analysis of covariance was used, with the time for the evaluated stage as the covariable. In all tests, a significance level of 5% (P <0.05) was adopted. RESULTS: From the evaluation of bone density, the results showed that the laser improved the opening of the midpalatal suture and accelerated the bone regeneration process. CONCLUSIONS: The low-level laser, associated with rapid maxillary expansion, provided efficient opening of the midpalatal suture and influenced the bone regeneration process of the suture, accelerating healing.

Avaliação das alterações dentárias na maxila em pacientes submetidos à expansão rápida da maxila assistida cirurgicamente sem o envolvimento da sutura pterigomaxilar / Assessment of maxillary dental changes in patients submitted to surgically assisted rapid maxillary expansion with no involvement of pterygoid blade

OBJETIVO: avaliar as alterações nos arcos dentários superiores no sentido transversal e a quantidade de inclinações nos dentes de apoio do aparelho de expansão tipo Hyrax em pacientes submetidos à expansão rápida da maxila assistida cirurgicamente (ERMAC) e a efetividade dessa técnica cirúrgica utilizada. A amostra foi composta por 34 pares de modelos de gesso de 17 pacientes, sendo 6 do gênero masculino e 11 do gênero feminino. MÉTODOS: as medidas foram realizadas em modelos de gesso por meio de medição das alterações nos planos vertical e transversal. O procedimento cirúrgico adotado foi uma osteotomia nas paredes laterais da maxila sem o envolvimento da lâmina pterigoide, osteotomia da espinha nasal à linha média dentária (incisivos centrais anteriores), separação da sutura palatina mediana por meio de cinzel e separação do septo nasal. O início das ativações ocorreu no terceiro dia pós-operatório, sendo uma pela manhã e uma à noite. RESULTADOS: houve expansão significativa estatisticamente na região dos caninos, primeiros e segundos pré-molares, primeiros e segundos molares, respectivamente de 6,03mm, 9,82mm, 8,66mm, 9,72mm e 5,67mm. Avaliando o comportamento dos dentes de apoio do disjuntor quanto às inclinações das coroas dentárias, notou-se que ocorreu uma vestibularização assimétrica, pois para os primeiros molares os valores encontrados foram 6,89º (direito) e 9,56º (esquerdo), e para os primeiros pré-molares os valores obtidos foram 4,74º (esquerdo) e 3,26º (direito), sendo esse considerado estatisticamente não-significativo. CONCLUSÕES: a técnica cirúrgica empregada para esta pesquisa mostrou ser eficiente para se obter alteração transversal maxilar, ocorrendo inclinação dentoalveolar dos dentes de apoio do disjuntor.

AIM: To assess the changes to the superior dental arches, in the transversal direction, and the amount of inclinations in the support teeth of the Hyrax expansion appliance in patients who underwent surgically assisted rapid maxillary expansion (SARME), as well as the effectiveness of the surgical technique used. The sample was composed of 34 pairs of cast models, of 17 patients - 6 males and 11 females. METHODS: The measurements were performed on cast models, by measuring the changes on the vertical and transversal planes. The surgical procedure used was the lateral osteotomy on maxillary walls with no involvement of the pterygoid blade, osteotomy of nasal spine on dental midline (anterior central incisors), chisel separation of palatine suture, and separation of the nasal septum. The activation was initiated on the third postoperative day, consisting of two activations, one in the morning and another at night. RESULTS: There were statistically significant expansions in the regions of canines, first and second premolars, first molars, and second molars; respectively, 6.03 mm, 9.82 mm, 8.66 mm, 9.72 mm, and 5.67 mm. The evaluation of the behavior of the support teeth of the expansion appliance regarding the inclination of the dental crowns has shown that an asymmetric vestibularization had taken place, because the values found for the first molars were 6.89º (right) and 9.56º (left); the values for the first premolars were 4.74º (left) and 3.26º (right); this last value was not statistically significant. CONCLUSIONS: The surgical technique used in this research has been shown to be efficient to obtain maxillary transversal alterations, and there was dental-alveolar inclination of the support teeth of the expansion appliance.

Hyrax appliance opening and pattern of skeletal maxillary expansion after surgically assisted rapid palatal expansion: a computed tomography evaluation.

OBJECTIVE: The objective of this study was to evaluate, using computed tomography, correlations between Hyrax appliance opening and post-SARPE skeletal changes. STUDY DESIGN: Fifteen patients underwent SARPE according to a specific protocol and were followed. Linear and angular measurements of the anterior, intermediate, and posterior portions of the maxilla were evaluated. The correlation between maxillary expansion and appliance opening was investigated. RESULTS: Significant overall expansion was observed. In the anterior and intermediate portions of the maxilla, the increase in maxillary width was greater than that observed in the posterior portion. The degree of appliance opening was significantly greater than that of the skeletal expansion. Also, no linear correlation between appliance opening and regional maxillary expansion was established. CONCLUSION: The transverse expansion of the maxilla was less than uniform. The lack of linear correlation between appliance opening and skeletal expansion is attributable to multiple factors, including those related to the device, the surgical technique, and the craniofacial deformity itself.

Using computed tomography to evaluate maxillary changes after surgically assisted rapid palatal expansion.

Surgically assisted rapid palatal expansion (SARPE) is the procedure of choice for treating transverse maxillary deficiency in adult patients. The use of computed tomography (CT) as a method of evaluating the efficiency of this procedure has not been yet reported. Consequently, few landmarks for use in evaluating maxillary expansion have been defined. The goals of the present study were to define parameters to assess skeletal changes after SARPE and to use CT to evaluate those parameters. From June of 2004 to May of 2005, 15 patients underwent SARPE (a modified Le Fort I maxillary osteotomy without pterygomaxillary separation, together with a sagittal palatal osteotomy) according to a defined protocol. To determine the pattern of transversal expansion, linear and angular measurements of the anterior, intermediate, and posterior portions of the maxilla were evaluated in axial and coronal views. The cross-sectional area of the maxilla was calculated to obtain general information about maxillary expansion. The reliability of the method was confirmed. Significant overall expansion was observed. However, different patterns of expansion were seen in the three regions analyzed. In the anterior and intermediate portions of the maxilla, the increase in maxillary width was greater than that observed in the posterior portion. The transverse expansion of the maxilla achieved through SARPE without pterygoid plate separation was less than uniform. The accurate evaluation of the postoperative changes was heavily dependent upon images acquired through CT.

Assessment of mandibular growth and response to orthopedic treatment with 3-dimensional magnetic resonance images.

INTRODUCTION: Three-dimensional (3D) craniofacial images are commonly used in clinical studies in orthodontics to study developmental and morphologic relationships. METHODS: We used 3D magnetic resonance imaging to study relationships among craniofacial components during the pubertal growth spurt and in response to Fränkel appliance therapy. The sample for this prospective study was 156 high-resolution magnetic resonance images with 1 mm isotropic voxel resolution of 78 subjects taken initially (T1) and 18 +/- 1 months (T2) after treatment or an observation period. The subjects were Brazilian children; 28 were treated and 25 were untreated for Class II malocclusion, and 25 were untreated with normal occlusions. A Procrustes geometric transformation of 3D skeletal landmarks was used to assess growth or treatment alterations from T1 to T2. The landmarks were located on the mandibular rami and the other craniofacial parts specifically related to the mandibular growth (the middle cranial fossae and the posterior part of the bilateral nasomaxilla). This allowed visualization of the entire volumetric dataset with an interactive 3D display. RESULTS: Statistically significant differences were found in the relative 3D skeletal growth directions from T1 to T2 for treated vs untreated Class II children (Bonferroni-adjusted P < .001) and for treated Class II vs normal-occlusion subjects ( P < .001). The major differences in the treated group were increased mandibular rami vertical dimensions and more forward rami relative to the posterior nasomaxilla and the middle cranial fossae. Principal component analysis made it possible to show individual variability and group differences in the principal dimensions of skeletal change. CONCLUSIONS: These methods are generalizable to other imaging techniques and 3D samples, and significantly enhance the potential of systematically controlled data collection and analysis of bony structures in 3 dimensions for quantitative assessment of patient parameters in craniofacial biology.

Comparison of relative mandibular growth vectors with high-resolution 3-dimensional imaging.

INTRODUCTION: The mandibular rami and their endochondrally growing condyles develop in many directions relative to the variable anatomic patterns of the nasomaxilla and middle cranial fossae during growth and response to orthopedic treatment. METHODS: High-resolution magnetic resonance images were used to compare 3-dimensional (3D) growth vectors of skeletal displacement and bone remodeling in 25 untreated subjects with Class II malocclusions, 28 subjects with Class II malocclusions who were treated with Fränkel appliance therapy, and 25 subjects with normal occlusions. Marked differences were noted over an 18-month observation period. The 3D coordinates of anatomic landmarks were registered by Procrustes fit to control for rotation, translation, and scale differences. RESULTS: Compared with untreated Class II and normal-occlusion subjects, the treated group showed highly significant differences in the 3D displacement/remodeling vectors of gonion and pterygomaxillary fissure relative to condylion and middle cranial fossae bilateral skeletal landmarks, by using both permutation tests ( P < .001) and a general linear multivariate model ( P < .0001). CONCLUSIONS: In a prospective and systematically controlled study, we quantitatively described significant 3D rami skeletal compensations in the structural assembly of facial morphogenesis at the beginning of the adolescent growth spurt using novel modeling techniques. These techniques have facilitated quantification of relative 3D growth vectors to illustrate skeletal changes with Fränkel appliance therapy. Future studies are required to assess the long-term clinical significance of our findings.

Clinical outcomes of Fränkel appliance therapy assessed with a counterpart analysis.

To evaluate whether the Fränkel Regulator-II (FR-II) induced mandibular growth rotations relative to the nasomaxilla and the middle cranial fossae, cephalometric changes in 28 treated Brazilian children were compared with changes in 28 untreated Class II children and in 28 children with normal occlusion. According to Enlow's counterpart analysis, the 3 groups were not significantly different initially in ramus alignment or relative ramus vertical dimension. These jaw relationships were maintained in both untreated groups. In the treated group, all children had overjet reduction, with correction of the dental arch relationship in 26 of the 28, and there was a significant trend toward a more forward ramus alignment (P =.002) and increased ramus relative vertical dimension (P =.0002). These treatment-induced changes showed a negative correlation with ramus alignment; ie, greater improvement was more likely in children who had backward ramus alignment before treatment and whose Class II malocclusion had not already been intrinsically compensated. Changes in the treated children were similar to but greater than those in the normal children, and different from those in the untreated Class II group. The data suggest that studies of skeletal variations with counterpart analysis can show ramus remodeling compensations from treatment that are missed with conventional cephalometrics.

Clinical outcomes of Frãnkel appliance therapy assessed with a counterpart analysis / Resultado clínico do aparelho de Frankel avaliado por terapia com uma análise complementar

To evaluate whether the Frãnkel Regulator-II (FR-II) induced mandibular growth rotations relative to the nasomaxilla and the middle cranial fossae, cephalometric changes in 28 treated Brazilian children were compared with changes in 28 untreated Class II children and in 28 children with normal occlusion. According to Enlow`s counterpart analysis, the 3 groups were not significantly different initially in ramus alignment or relative ramus vertical dimension. These jaw relationships were maintained in both untreated groups. In the treated group, all children had overjet reduction, with correction of the dental arch relationship in 26 of the 28, and there was a significant trend toward a more forward ramus alignment (P = .002) and increased ramus relative vertical dimension (P = .0002). These treatment-induced changes showed a negative correlation with ramus alignment/ ie, greater improvement was more likely in children who had backward ramus alignment before treatment and whose Class II malocclusion had not already been intrinsically compensated. Changes in the treated children were similar to but greater than those in the normal children, and different from those in the untreated Class II group. The data suggest that studies of skeletal variations with counterpart analysis can show ramus remodeling compensations from treatment that are missed with conventional cephalometrics