Cone beam computed tomography evaluation of midpalatal suture maturation in adults.

The aim of this study was to evaluate midpalatal suture maturation in adults, as observed in cone beam computed tomography (CBCT) images. CBCT scans from 78 subjects (64 female and 14 male, age range from 18 to 66 years) were evaluated. Midpalatal suture maturation was verified on the central cross-sectional axial slice in the superior-inferior dimension of the palate, using methods validated previously. Intra-examiner agreement was analyzed by weighted kappa test. Multinomial logistic regression was used to test whether sex and chronological age (adults <30 years or ≥30 years) could be used as a predictor for the maturational stages of the midpalatal suture. The majority of the adults presented a fused midpalatal suture in the palatine (stage D) and/or maxillary bones (stage E). However, the midpalatal suture was not fused in 12% of the subjects. Sex and chronological age were not significant predictors of the maturational stages of the midpalatal suture. The individual assessment of midpalatal suture maturation by way of CBCT images may provide reliable information critical to making the clinical decision between rapid maxillary expansion and surgically assisted rapid maxillary expansion for the treatment of maxillary atresia in adults.

Zygomaticomaxillary suture maturation: Part II-The influence of sutural maturation on the response to maxillary protraction.

OBJECTIVE: To evaluate the influence of the maturational stages of zygomaticomaxillary sutures (ZMS) on the response to maxillary protraction. SUBJECTS AND METHODS: A total of 40 Class III patients were treated retrospectively with either a combination of rapid maxillary expansion and facial mask (RME/FM) or bone-anchored maxillary protraction (BAMP). The RME/FM group consisted of 18 patients (mean age 8.3 years), while the BAMP group was comprised of 22 patients (mean age 11.8 years). The initial CBCT images (T1) of the ZMSs were classified blindly. 3D models from CBCT images at the start and at the end of orthopaedic treatment were registered on the anterior cranial base, and corresponding structures were measured on colour-coded maps and semitransparent overlays. The amounts of protraction of the maxilla, zygoma, orbitale and maxillary first molars for both groups were analysed with two-way ANOVA with Holm-Sidak post hoc test for multiple comparisons. RESULTS: A significant association was found between the early maturation stages of the ZMSs and the amount of maxillary protraction, regardless of the protraction method used. Class III patients with ZMS stages A and B showed greater maxillary protraction than patients at stage C. CONCLUSION: The maturational stages of ZMS are associated with the response maxillary protraction.

Zygomaticomaxillary suture maturation: A predictor of maxillary protraction? Part I - A classification method.

OBJECTIVE: The aim of this study was to present a method of classifying the maturational level of the zygomaticomaxillary sutures (ZMSs). METHODS: Cone-beam CT (CBCT) images from 74 subjects (5.6-58.4 years) were examined to define the radiographic stages of ZMS maturation. Five stages of maturation of the ZMS were identified and defined: Stage A-uniform high-density sutural line, with no or little interdigitation; Stage B-scalloped appearance of the high-density sutural line; Stage C-two parallel, scalloped, high-density lines, separated in some areas by small low-density spaces; Stage D-fusion in the inferior portion of the suture; and Stage E-complete fusion. Intra- and inter-examiner agreements were evaluated by weighted kappa tests. RESULTS: The intra- and inter-examiners reproducibility values demonstrated substantial to almost perfect agreement. No fusion of ZMSs was observed in patients up to 10 years of age. From 10 to 15 years, all maturational stages were identified. After 15 years of age, the majority of patients showed fusion of ZMSs. CONCLUSIONS: The classification of ZMS maturation using CBCT is a reliable method that allows the assessment of the morphology of the ZMSs in the individual patient.

Three-dimensional skeletal mandibular changes associated with Herbst appliance treatment.

OBJECTIVES: Three-dimensional evaluation of skeletal mandibular changes following Herbst appliance treatment. SETTING AND SAMPLE POPULATION: Retrospective case-control study, based on a sample size calculation. Twenty-five pubertal patients treated with Herbst appliance (HAG), and 25 matched Class II patients who received other non-orthopaedic dental treatments (CG). MATERIAL AND METHODS: Three-dimensional models were generated from pre-treatment (T0) and post-treatment (T1) cone beam computed tomograms. Volumetric registration on the cranial base was used to assess mandibular displacement; volumetric regional registration was performed to evaluate mandibular growth. Quantitative measurements of X, Y, Z and 3D Euclidian changes, and also qualitative visualization by colour-mapping and semi-transparent overlays were obtained. RESULTS: Downward displacement of the mandible was observed in both HAG and CG (2.4 mm and 1.5 mm, respectively). Significant forward displacement of the mandible was observed in the HAG (1.7 mm). HAG showed greater 3D superior and posterior condylar growth than the CG (3.5 mm and 2.0 mm, respectively). Greater posterior growth of the ramus was noted in the HAG than in CG. CONCLUSIONS: Immediately after Herbst therapy, a significant mandibular forward displacement was achieved, due to increased bone remodelling of the condyles and rami compared to a comparison group. Three-dimensional changes in the direction and magnitude of condylar growth were observed in Herbst patients.

Lateral cephalometric standards of Germans with normal occlusion from 6 to 17 years of age.

The aim of this study was to analyze sagittal and vertical dentofacial dimensions in subjects with normal occlusions during the juvenile and adolescents age periods to establish age- and gender-specific lateral cephalometric standard values for Germans during their active growth period. The study group consisted of a sample of 32 untreated subjects with normal occlusions. Lateral cephalograms were analyzed at 11 consecutive stages, from 6-13 and from 15-17 years of age. A customized cephalometric analysis was used to measure 53 variables. Statistical comparisons of gender-specific differences were performed by means of Mann-Whitney U tests.Anterior and posterior cranial base lengths, midfacial length as well as mandibular length were recorded to be significantly larger in male subjects at the age of 6 years. For most of the linear measurements, significantly larger craniofacial distances were recorded in males from the age of 15 years onward. There were no statistically significant gender differences with regard to most angular measurements at subsequent age groups. Soft tissue analysis revealed flatter profiles in females than in males from the age of 10-11 years onward, while age-dependent changes in the soft tissue profile were similar in both genders.In untreated subjects with normal occlusion craniofacial development of the hard and soft tissues can be considered age- and gender-dependent. Therefore age- and gender-specific differences of linear craniofacial distances should be taken into account for diagnosis and treatment planning in children and adolescents. The present results can be used as reference values for children and adolescents of German origin.

Treatment timing for rapid maxillary expansion.

The aim of this study was to evaluate the short-term and long-term treatment effects of rapid maxillary expansion in 2 groups of subjects treated with the Haas appliance. Treatment outcomes were evaluated before and after the peak in skeletal maturation, as assessed by the cervical vertebral maturation (CVM) method, in a sample of 42 patients compared to a control sample of 20 subjects. Posteroanterior cephalograms were analyzed for the treated subjects at T1 (pretreatment), T2 (immediate post-expansion) and T3 (long-term observation), and were available at T1 and at T3 for the controls. The mean age (years: months) at T1 was 11:10 for both the treated and the control groups. The mean ages at T3 also were comparable (20:6 for the treated group and 17:8 for the controls). Following expansion and retention (2 months on average), fixed standard edgewise appliances were placed. The study included transverse measurements on dentoalveolar structures, maxillary and mandibular bases and other craniofacial regions (nasal, zygomatic, orbital, and cranial). Treated and control samples were divided into 2 groups according to individual skeletal maturation. The early-treated and early-control groups had not reached the pubertal peak in skeletal growth velocity at T1 (CVM 1 to 3), whereas the late-treated and late-control groups were during or slightly after the peak at T1 (CVM 4 to 6). The group treated before the pubertal peak showed significantly greater short-term increases in the width of the nasal cavities. In the long-term, maxillary skeletal width, maxillary intermolar width, lateronasal width, and lateroorbitale width were significantly greater in the early-treated group. The late-treated group exhibited significant increases in lateronasal width and in maxillary and mandibular intermolar widths. Rapid Maxillary Expansion treatment before the peak in skeletal growth velocity is able to induce more pronounced transverse craniofacial changes at the skeletal level.

Thin-plate spline analysis of mandibular growth.

The analysis of mandibular growth changes around the pubertal spurt in humans has several important implications for the diagnosis and orthopedic correction of skeletal disharmonies. The purpose of this study was to evaluate mandibular shape and size growth changes around the pubertal spurt in a longitudinal sample of subjects with normal occlusion by means of an appropriate morphometric technique (thin-plate spline analysis). Ten mandibular landmarks were identified on lateral cephalograms of 29 subjects at 6 different developmental phases. The 6 phases corresponded to 6 different maturational stages in cervical vertebrae during accelerative and decelerative phases of the pubertal growth curve of the mandible. Differences in shape between average mandibular configurations at the 6 developmental stages were visualized by means of thin-plate spline analysis and subjected to permutation test. Centroid size was used as the measure of the geometric size of each mandibular specimen. Differences in size at the 6 developmental phases were tested statistically. The results of graphical analysis indicated a statistically significant change in mandibular shape only for the growth interval from stage 3 to stage 4 in cervical vertebral maturation. Significant increases in centroid size were found at all developmental phases, with evidence of a prepubertal minimum and of a pubertal maximum. The existence of a pubertal peak in human mandibular growth, therefore, is confirmed by thin-plate spline analysis. Significant morphological changes in the mandible during the growth interval from stage 3 to stage 4 in cervical vertebral maturation may be described as an upward-forward direction of condylar growth determining an overall "shrinkage" of the mandibular configuration along the measurement of total mandibular length. This biological mechanism is particularly efficient in compensating for major increments in mandibular size at the adolescent spurt.

Patient-initiated second medical opinions: their necessity and economic cost.

PURPOSE: To assess the value of patient-initiated second medical opinions (SMO). METHODS: The authors prospectively collected demographic data from 100 consecutive patients. The authors recorded major changes in the patients' care, such as inappropriate surgery recommended, inadequate treatment performed, and appropriate treatment not recommended. The authors also recorded costs incurred or saved by the patients and the third-party payers. RESULTS: In nearly 15 of the cases, the authors had major disagreements with the initial diagnosis or management. Surgery had been recommended in 28 cases. They advised against it in nine. In 72 cases, no surgery had been recommended. They advised and performed it in five. The management of five other patients was not in accordance with that recommended by large clinical trials or was inadequately done. Including the consultation fees, surgery performed or advised against, retinal angiography, and ultrasonography, the 100 SMO cost third-party payers $12,426. If the authors subtract the cost of noncontroversial surgery they recommended and if the patients had paid the consultation fee and had brought along their fluorescein angiograms, third-party payers would have saved $4,079. CONCLUSION: The savings SMO generated by eliminating unnecessary surgery resulted in improved patient care at minimal cost to third-party payers.

Treatment and posttreatment craniofacial changes after rapid maxillary expansion and facemask therapy.

The aim of this study was to evaluate treatment and posttreatment dentoskeletal changes in 2 groups of subjects with Class III malocclusions. Subjects were treated with a bonded acrylic-splint expander and a face mask, and the optimal timing for this treatment protocol was assessed. The treated sample (29 subjects) was divided into 2 groups according to the stage of dental development. The early treatment group consisted of 16 subjects in the early mixed dentitional (erupting permanent incisors and/or first molars), whereas the late treatment group consisted of 13 subjects in the late mixed dentition (erupting permanent canines and premolars). Cephalograms were available at 3 time periods: T(1), pretreatment, T(2), end of active treatment, and T(3), posttreatment. The mean T(1)-T(2) interval (active treatment period) and the mean T(2)-T(3) interval (posttreatment period) were approximately 1 year each in both treatment groups. None of the patients wore any skeletal retention appliance during the posttreatment period (T(2)-T(3)). Groups of subjects with untreated Class III malocclusion were used as controls at both observation intervals. A significant increase in the sagittal growth of the maxilla was seen only when treatment was performed in the early mixed dentition. A restraining effect on mandibular growth rate associated with a more upward and forward direction of condylar growth was found in both treatment groups. An increase in vertical intermaxillary relationships was observed in Class III patients treated in the late mixed dentition. Posttreatment, the Class III craniofacial growth pattern was re-established in the absence of any skeletal retention appliance. Relapse tendency affects the sagittal growth of the maxilla in the early treated subjects and the sagittal position of the mandible in the late treated subjects. Orthopedic treatment of Class III malocclusion in the early mixed dentition is able to induce more favorable craniofacial adaptations than treatment in the late mixed dentition.

Mandibular growth as related to cervical vertebral maturation and body height.

The purpose of this study was to analyze the validity of 6 stages of cervical vertebral maturation (Cvs1 through Cvs6) as a biologic indicator for skeletal maturity in 24 subjects (15 females, 9 males). The method was able to detect the greatest increment in mandibular and craniofacial growth during the interval from vertebral stage 3 to vertebral stage 4 (Cvs3 to Cvs4), when the peak in statural height also occurred. The prevalence rate of examined subjects who presented with the peak in body height at this interval was 100% for boys and 87% for girls. Statural height and total mandibular length (Co-Gn) showed significant increments during the growth interval Cvs3 to Cvs4 when compared with the growth interval Cvs2 to Cvs3, and significant growth deceleration occurred during the interval Cvs4 to Cvs5 when compared with Cvs3 to Cvs4. Ramus height (Co-Goi) and S-Gn also showed significant deceleration of growth during the interval Cvs4 to Cvs5 when compared with Cvs3 to Cvs4. Cervical vertebral maturation appears to be an appropriate method for the appraisal of mandibular skeletal maturity in individual patients on the basis of a single cephalometric observation and without additional x-ray exposure. The accuracy of the cervical vertebral method in the detection of the onset of the pubertal spurt in mandibular growth provides helpful indications concerning treatment timing of mandibular deficiencies.

A comparative study of two methods of quantifying the soft tissue profile.

One of the most important components of orthodontic diagnosis is the evaluation of the patient's soft tissue profile. There have been many attempts to quantify the soft tissue profile based on the lateral cephalogram. Yet, the methodology used to evaluate the profile varies widely among studies, and there has been no consistency in the way straight lines are constructed in the analysis of the soft tissue contours. The purpose of the current study was to compare the values obtained by 2 drawing methods (tangent line and anatomic points) of constructing angles, and to assess the intraobserver and interobserver reproducibility for both methods. There were statistically significant differences between the 2 methods for 9 of the 10 measurements evaluated. In the comparison of reproducibility assessed by Pearson correlation analysis, both methods showed statistically significant correlations between repeated measurements. The anatomic point method, however, showed greater reproducibility by means of a paired t-test. In the analysis of intraobserver reproducibility, 2 measurements showed significant differences with the anatomic point method and 4 measurements demonstrated significant differences when the tangent line method was used. In the analysis of interobserver reproducibility, 5 measurements showed significant differences in the anatomic point method, while 6 measurements represented significant differences in the tangent line method. Our results indicate that a precise description of the methodology used in the analysis of the soft tissue must be provided because of the differences between methods. In the analysis of soft tissue contours, the construction of lines with the anatomic point method is more reproducible than the tangent line method.

Treatment timing for Twin-block therapy.

This cephalometric study evaluated skeletal and dentoalveolar changes induced by the Twin-block appliance in 2 groups of subjects with Class II malocclusion treated at different skeletal maturation stages in order to define the optimal timing for this type of therapy. Skeletal maturity in individual patients was assessed on the basis of the stages of cervical vertebrae maturation. The early-treated group was composed of 21 subjects (11 females and 10 males). Mean age of these subjects at time 1 (immediately before treatment) was 9 years +/- 11 months, and at time 2 (immediately after discontinuation of the Twin-block appliance) was 10 years 2 months +/- 11 months. According to the cervical vertebrae maturation staging at times 1 and 2, the peak in growth velocity was not included in the treatment period for any of the subjects in the early group. The late-treated group consisted of 15 subjects (6 females and 9 males). Mean age of this group was 12 years 11 months +/- 1 year 2 months at time 1 and 14 years 4 months +/- 1 year 3 months at time 2. In the late group, treatment was performed during or slightly after the onset of the pubertal growth spurt. Both treated samples were compared with control samples consisting of subjects with untreated Class II malocclusions also selected on the basis of the stage in cervical vertebrae maturation. A modification of Pancherz's cephalometric analysis was applied to the lateral cephalograms of all examined groups at both time periods. Linear and angular measurements for mandibular dimensions, cranial base angulation, and vertical relationships were added to the original analysis. Annualized differences for all the variables from time 1 to time 2 were calculated for both treated groups and contrasted to the annualized differences in the corresponding untreated groups by means of nonparametric statistics. The findings of this short-term cephalometric study indicate that optimal timing for Twin-block therapy of Class II disharmony is during or slightly after the onset of the pubertal peak in growth velocity. When compared with treatment performed before the peak, late Twin-block treatment produces more favorable effects that include: (1) greater skeletal contribution to molar correction, (2) larger increments in total mandibular length and in ramus height, and (3) more posterior direction of condylar growth, leading to enhanced mandibular lengthening and to reduced forward displacement of the condyle in favor of effective skeletal changes. The importance of the biological evaluation of skeletal maturity in individual patients with Class II disharmony to be treated with functional appliances is emphasized.

Midfacial morphology of Koreans with class III malocclusions investigated with finite-element scaling analysis.

The spheno-ethmoidal model of midfacial retrognathia suggests that deficient chondrocytic proliferation in the anterior cranial base is associated with inadequate anterior translation of the midfacial complex resulting, for example, in Class III malocclusions. The purpose of this study was to determine whether the morphology of the midface differed in subjects of diverse ethnic origin exhibiting features associated with Class III malocclusions. Lateral cephalographs of 142 children of Korean or European American descent aged between 5 and 11 years were compared. The cephalographs were traced and subdivided into seven age- and sex-matched groups. Average geometries, scaled to an equivalent size, were generated using Procrustes superimposition and subjected to analysis of variance (ANOVA). Graphical analysis using a color-coded finite-element scaling analysis (FESA) program was used to localize differences in morphology. Results indicated that the mean Korean and European American midfacial configurations differed statistically (P < 0.01), and this difference was maintained at most, but not all, age-wise comparisons. Comparing Korean and European American Class III midfacial configurations for local size-change, FESA analysis revealed that while local increases in size were apparent in the posterior palatal regions, the Korean anterior nasal spine regions were generally smaller. For shape-change, the Korean and European American midfacial configurations were predominantly isotropic. Therefore, heterogeneity in appearance may be influenced by morphological variation of the midfacial complex in subjects of diverse ethnic origin, but features of the anterior cranial base may contribute also to the prevalence and severity of Class III malocclusions in Koreans. Moreover, perturbations in endochondral mechanisms of cranio-mandibular growth, and not maxillary intramembranous methods, may be implicated in the etiology of Class III malocclusions in South East Asians.

Comparison of mandibular morphology in Korean and European-American children with Class III malocclusions using finite-element morphometry.

The purpose of this study was to determine whether the morphology of the mandible differed in subjects of diverse ethnic origin exhibiting Class III malocclusions. Lateral cephalographs of 147 children of either Korean or European-American descent aged between 5 and 11 years were compared. The cephalographs were subdivided into seven age- and sex-matched groups, traced, and eight mandibular homologous landmarks digitized. Average mandibular geometries, scaled to an equivalent size, were computed using Procrustes superimposition and subjected to ANOVA. Graphical analysis using a colour-coded finite element (FEM) programme was used to localize differences in morphology. Results indicated that the overall mean Korean and European-American mandibular configurations differed statistically (P < 0.001) and statistical difference was maintained at all age-wise comparisons. Comparing Korean and European-American Class III mandibular configurations for local size-change, FEM analysis revealed that the Korean condylar and mental regions generally were smaller (approximately 15-20 per cent decrease in size, respectively). However, an antero-posterior increase in the size of the mandibular corpus was most apparent in the incisor alveolus region (approximately 35 per cent increase in size). For shape-change, the Korean and European-American mandibular configurations were fairly isotropic except in the symphyseal and incisor alveolus regions. Dissimilarities in mandibular morphology are identifiable particularly in the dento-alveolar regions in subjects of diverse ethnic origin exhibiting Class III malocclusions. These differences may reflect genetic and/or environmental influences that might determine the severity and prevalence of the condition, and its subsequent clinical management.

Dentoalveolar and skeletal changes associated with the pendulum appliance.

The purpose of the study was to examine the dentoalveolar and skeletal effects of the pendulum appliance in Class II patients at varying stages of dental development and with varying facial patterns (high, neutral, and low mandibular plane angles). Specifically, the amount and nature of the "distalization" of the maxillary first molars and the reciprocal effects on the anchoring maxillary first premolars and incisors were studied, as were skeletal changes in the sagittal and vertical dimensions of the face. Pretreatment and posttreatment cephalometric radiographs obtained from 13 practitioners were used to document the treatment of 101 patients (45 boys and 56 girls). The average maxillary first molar distalization was 5.7 mm, with a distal tipping of 10.6 degrees. The anchoring anterior teeth moved mesially, as indicated by the 1.8-mm anterior movement of the upper first premolars, with a mesial tipping of 1.5 degrees. The maxillary first molars intruded 0.7 mm, and the first premolars extruded 1.0 mm. Lower anterior facial height increased 2.2 mm; there was no significant difference in lower anterior facial height increase between patients of high, neutral, or low mandibular plane angles. In patients with erupted maxillary second molars, there was a slightly greater increase in lower anterior face height and in the mandibular plane angle and a slightly greater decrease in overbite in comparison to patients with unerupted second molars. Similar findings were observed in patients with second premolar anchorage versus those with second deciduous molar anchorage. The results of this study suggest that the pendulum appliance is effective in moving maxillary molars posteriorly during orthodontic treatment. For maximum maxillary first molar distalization with minimal increase in lower anterior facial height, this appliance is used most effectively in patients with deciduous maxillary second molars for anchorage and unerupted permanent maxillary second molars, although significant bite opening was not a concern in any patient in this study.

Neuromuscular and skeletal adaptations following mandibular forward positioning induced by the Herbst appliance.

The purpose of this study was to examine neuromuscular and skeletal adaptations to changes in sagittal jaw relationships induced by the Herbst appliance. Six patients (age, 9 years and 5 months to 11 years and 2 months) with Angle Class II, division 1 malocclusions were studied longitudinally. The structural changes were determined by analyzing serial lateral cephalograms. Electromyographic recordings of specific masticatory muscles were used to evaluate neuromuscular adaptations. Similar cephalometric changes were observed in all patients. In all patients, lateral pterygoid muscle activity increased immediately after insertion of the appliance, but the activity decreased markedly after 4 to 6 months of treatment. In 4 of the 6 patients studied, however, the condyles were located in a slightly more downward and forward position. These findings indicate that the adaptation of muscular function occurs within a relatively short period and precedes the compensatory morphological changes produced through functional appliance therapy.

Allometry of the cranial base in prepubertal Korean subjects with class III malocclusions: finite element morphometry.

Sphenoethmoidal allometry could be associated with ethnic heterogeneity of the midfacial profile. Thirteen cranial base landmarks were digitized from cephalographs of 69 Korean and 73 European American prepubertal children exhibiting Class III malocclusion. Average geometries were normalized, and a color-coded finite element (FEM) program was used to localize differences in morphology. ANOVA indicated that mean Korean and European American cranial base configurations differed statistically (p < 0.01); this was also true for seven age groups tested (p < 0.001). For size-change, FEM analysis revealed that in the anterior cranial base, Korean sphenoethmoidal and sella turcica regions were smaller (=12%). Local increases in size were apparent for the posterior region of the Korean cranial base (=35%). For shape-change, Korean and European American cranial base configurations were isotropic with minor anisotropy in the sphenoethmoidal and spheno-occipital regions. A sphenoethmoidal mechanism of midfacial retrognathism appears to be implicated in the development of a skeletal Class III morphology.