Vertical Skeletal Measurements Research Articles

Dentoalveolar bone height in Class I adults with different vertical patterns: A cross-sectional study

Facial divergence during growth and development affects both the anterior and posterior alveolar bone dimensions in the maxilla and mandible, and the dentoalveolar compensation mechanism in severe vertical skeletal discrepancies remains unclear. To evaluate the: (1) difference in dentoalveolar heights among subjects with different vertical facial patterns; (2) association between the dentoalveolar bone height and other cephalometric variables; (3) effect of sex on dentoalveolar height measurements. Non-growing subjects with skeletal Class I (0°<ANB<4°), Class I canine and molar relationship and complete fully erupted dentition were included in the study. Cephalometric measurements were taken on lateral cephalograms and patients were stratified into hyperdivergent, hypodivergent, and normodivergent groups based on MP/SN angle. A two-way analysis of variance (ANOVA) was used to compare cephalometric measurements between the divergence and sex groups. Measurements on a total of 204 patients (81 males, 123 females) were analysed. At the level of the incisor and premolar regions, both dentoalveolar and alveolar bone heights were significantly larger in hyperdivergent group when compared to hypodivergent group, whereas at the level of the molar region, no difference was found among groups. Moderate to strong correlations were found between dentoalveolar bone and vertical skeletal measurements. In the maxilla and mandible, the dentoalveolar compensation mechanism in skeletal Class I subjects results in an increased vertical height in the anterior dentoalveolar segment in hyperdivergent subjects and a reduced one in hypodivergent subjects.

A retrospective study evaluating the influence of Class III correction appliances on the sagittal pharyngeal airway dimension

The aim of this study was to compare the effects of Class III correction appliances including the Facemask (FM), and the new non-compliance fixed functional appliances such as the Reversed Forsus Fatigue Resistant Device (FRD), as well as the CS-2000 (CS), on the sagittal pharyngeal airway dimension (SPAD). Pre-treatment and post-treatment lateral cephalograms of 45 patients who underwent Class III appliance treatment, using either FM, Reversed FRD, or CS were collected from the files of treated patients. SPAD changes were evaluated in each group, and comparisons were conducted between the three study groups. Additionally, sagittal and vertical skeletal measurements were conducted. The FM, the Reversed FRD, and the CS, were found to generate a significant increase in the SPAD, with the Reversed FRD contributing to the most significant change at the OPAA (116.80 ± 26.36 mm2). All three appliances elicited significant antero-posterior changes in the SNA°, SNB°, and ANB°, also with the greatest intermaxillary change documented with the employment of the Reversed FRD (ANB° = 3.33 ± 0.82°). As for the vertical dimension, the FM, the Reversed FRD, and the CS elicited significant FMA° increases, with the greatest change attributed to the FM (FMA° = 2.32 ± 0.97°). Therefore, the three tested Class III corrective appliances generated significant SPAD, antero-posterior, and vertical changes. However, the Revered FRD showed a superior impact in increasing the SPAD at the OPAA level and in eliciting significant intermaxillary changes.

Cephalometric changes in pharyngeal airway dimensions after functional treatment with twin block versus myobrace appliances in developing skeletal class II patients: a randomized clinical trial

BackgroundSeveral appliances have been used for correction of developing skeletal Class II, including different myofunctional appliances as Twin block (TB)as well as the new pre-fabricated Myobrace (MB) appliance. However, the effects of these devices on the pharyngeal airways have not been compared in the literature. Thus, the aim of this study was to compare the effects of two Class II correction appliances; TB and MB on the sagittal pharyngeal airway dimension (SPAD), including the nasopharyngeal airway area (NPAA), the oropharyngeal airway area (OPAA), and the laryngopharyngeal airway area (LPAA).MethodsThis is a two parallel arms randomized comparative clinical trial. Twenty-six children of 9–12 years with Skeletal Class II malocclusion due to mandibular deficiency and normal maxillary growth as confirmed by lateral cephalometric X-ray readings (ANB angle > 4° and SNB angle < 78) and Cervical vertebral maturational index (CVMI) 1 or 2 were randomly assigned into two equal groups. Group I: TB, Group II: MB (prefabricated functional appliance, Myofunctional Research Co., Australia). Lateral cephalograms were taken for all patients in both groups before treatment (T1) and after treatment (6 months later) (T2). The primary aim was to assess pre and post treatment changes in the SPAD in each group, and compare between the two study groups. The secondary aim was to evaluate the sagittal skeletal measurements such as the SNA, SNB, ANB, Wits appraisal, as well as vertical skeletal measurements represented by the Frankfurt-mandibular plane angle (FMA) measured pre- and post-treatment. The independent samples t-test was used to compare the two study groups, and the mean difference and 95% confidence intervals (CI) were computed. The paired samples t-test was used to compare various parameters between T1 and T2 within each group. The cutoff for significance was p-value < 0.05. Data were analyzed using IBM SPSS for Windows (Version 26.0).ResultsBy Comparing changes in airway measurements within each group, it was found that NPAA, OPAA, and LPAA increased significantly after treatment within each group of MB and TB. TB group showed significantly higher mean difference (T2-T1) in both NPAA and OPAA than MB group with 28.39 (± 56.75) and 40.46 (± 52.16) respectively. The increase in LPAA values was not statistically significant at (T2-T1) between both groups. Regarding skeletal changes, there was a significant increase in the SNB values between T1 and T2 within each group with 2.82 (± 3.32) for MB group and 3.79 (± 3.06) for TB group Moreover, there was a significant decrease in the ANB values between T1 and T2 within each group by 2.42 (± 2.70) for MB group and 3.06 (± 1.14) for TB group. Similarly, there was a significant decrease in the ANB values between T1 and T2 within each group by -2.13 (± 0.62) for MB group and − 2.46 (± 0.72) for TB group. No significant differences were found between both groups in SNA, SNB, ANB and Wits appraisal at p = 0.06, p = 0.45, p = 0.43 and p = 0.22 respectively. FMA did not show significant difference between T1 and T2 within each group, nor showed a significant mean difference between both groups at T2-T1.ConclusionsTB was more effective than MB in improving the upper (NPAA) and middle (OPAA) airways, while no difference was found regarding the lower airway (LPAA). Both TB and MB reduced the severity of developing skeletal class II due to mandibular retrognathism by forward posturing of the mandible. Thus, patients with airway problems would benefit more from TB than MB.

Does the face mask increase the impact of rapid maxillary expansion on sagittal airway dimensions?

Airway dimensions associated with the transversal and sagittal position of the maxilla are affected by orthodontic treatment. The objective of this study was to compare the effects of rapid maxillary expansion (RME) and RME followed by face mask (FM) therapies on the airway space and investigate whether application of the FM increases the short-term and long- term impact of RME on sagittal airway dimensions. A total of 26 patients were divided into two groups. Group I included 14 adolescents treated with RME (3 males, 11 females; mean age: 12.2 11 ± 2.1 years), and Group II included 12 adolescents treated with RME followed by FM therapy (7 males, 5 females; mean age: 11.6 ± 1.3 years). Sagittal and vertical skeletal measurements, as well as ten linear cross-sectional airway measurements, were calculated from pretreatment, posttreatment, and postretention cephalometric radiographs. RME followed by FM resulted in a significant increase in the SNA angle, ANB angle, and Wits parameter by the forward movement of the maxillary bone. A significant increase in the vertical dimensions was also observed. Regarding the airway measurements in both groups, significant oropharyngeal increases were revealed, and these were maintained in the follow-up period. However, there were no other significant differences in the short-term and long-term results obtained for Groups I and II. The dimensions of the airway were significantly affected by both therapies. However, no additional effect of FM was observed.

Relationship between mandibular symphysis dimensions and skeletal pattern in adults.

The knowledge of dimensions of the symphysis is important for morphological and orthodontic studies. This research evaluates the association between mandibular symphysis dimensions and anteroposterior and vertical skeletal patterns in adults. This cross-sectional cephalometric study included 90 lateral cephalograms of untreated subjects presenting for orthodontic treatment. The inclusion criteria were adults with lateral cephalograms showing the symphyseal region and anterior cranial base. One investigator traced and analysed all cephalograms. Symphyseal height, thickness, and ratio between height and thickness were measured in relation to seven anteroposterior and vertical skeletal measurements in females and males. Symphyseal measurements were associated with SNAo (anteroposterior) in females and Gonial angle (vertical) in males. When analysed by anteroposterior skeletal classification (ANBo), no significant differences in symphyseal dimensions were found. Multiple linear regression analyses showed that Gonion-Nerve (mm) and Gonial angle were significantly associated with symphyseal height. Gonion-Nerve (mm), basal bone width (mm), and alveolar bone height (mm) were associated with symphyseal thickness. Basal bone width (mm) and alveolar bone height (mm) were associated with symphyseal ratio. Symphyseal dimensions were significantly associated with vertical but not anteroposterior skeletal patterns. Future studies are warranted to evaluate the Gonion-Nerve measurements concerning the symphysis in relation to vertical and anteroposterior skeletal patterns.

Postpubertal Effects of the Rapid Maxillary Expansion and Facial Mask versus the Removable Mandibular Retractor for the Early Treatment of Class III Malocclusion: A Study on Lateral Cephalograms

The aim of this study was to compare the efficacy of early treatment of Class III malocclusions with rapid maxillary expansion (RME) and facial mask (FM) versus the removable mandibular retractor (RMR) re-evaluated at a postpubertal observation on lateral cephalograms. All prepubertal patients with Class III malocclusion treated consecutively from 1986 to 2013 by means of RME/FM or RMR were analyzed. Twenty-nine patients treated with RME/FM therapy and 23 patients treated with RMR were selected. Lateral cephalograms were available at 3 time points, before treatment (T1), at the end of active treatment (T2), and at a postpubertal observation (T3). Statistical comparisons were performed with independent sample t tests or Mann–Whitney tests. During the T1–T3 interval, a significantly greater maxillary protraction (SNA +1.5 mm, p = 0.031) and significantly greater improvements in ANB and Wits appraisal (+1.9 degrees, p = 0.002, and +2.2 mm, p = 0.012, respectively) were recorded in the RME/FM group. No statistically significant changes could be found in vertical skeletal measurements. In the dentoalveolar region, the RME/FM group showed a significantly greater correction of the molar relationship (−1.5 mm, p = 0.021). Early treatment of Class III malocclusion with RME/FM protocol in comparison with RMR protocol showed a greater maxillary advancement and greater improvements in sagittal skeletal Class III relationships.

Morphological features of Class I, II and III malocclusions of Saudi adolescents.

AimsThis cross-sectional study compared and contrasted the morphological characteristics of Class I, II and III malocclusions in an adolescent Saudi population.MethodsAdolescent Saudis with Angle’s Class I, II and III malocclusions were selected from orthodontic patients’ records. Angular and linear measurements were compared between the three groups. Cephalometric analysis was performed using the VistadentOC® software. Multifactorial ANOVA for angular and linear measurements between and within groups.ResultsOrthodontic records of 300 patients were included. There was no significant difference between and within groups in age and distribution of Angle’s classification, p > 0.05. Multifactorial ANOVA showed that there were significant interactions between gender and malocclusions in skeletal, dental and soft tissue measurements, p < 0.05. There were significant differences in the sagittal and vertical skeletal measurements between groups, p < 0.05. The dental measurements were also significantly different in most of the measurements (p < 0.05). Moreover, there were significantly different readings among the groups in the soft tissue analysis.ConclusionMorphological characteristics of adolescent Saudis show unique differences between gender and malocclusions, more so in Class III malocclusions. Class II and III malocclusions also show skeletal differences amongst the groups.

THE TREATMENT EFFECTS OF THE COMBINED APPROACH: BRACESWITH PREFABRICATED MYOFUNCTIONALAPPLIANCE FOR GROWING CLASS II PATIENT

Objective:To evaluate the effect of combined treatment approach: braces with myofunctional appliance (trainer-T4B) on dentoalveolar, sagittal and vertical skeletal level in growing individuals with Skeletal and Dental Class II. Methods:Twenty teenagers with permanent dentition were treated with fixed appliance-braces in combination with myofunctional appliance (trainer-T4B). All patient completed thetreatment with occlusal Class I molar relationship. The patients made initial and final profile X-rays with cephalometric analysis. The evaluation of the treatment effects was made by comparing the initial and the final cephalometric analysis. Results:Significant sagittal skeletal changes were observed on all sagittal skeletal parameters, except for SNA°. A high positive association was found between the ANB angle change and Wits change. The changes in the rest of the vertical skeletal measurements were significant for two, including SN-M° and Go°. The dentoalveolar measurements showedsignificant changes in all parameters, except for i/M° where the change was marginally significant. Conclusion:The chosen treatment approachwaseffective for growing skeletal and dental Class II patients with permanent dentition.

Relationship between vertical components of maxillary molar and craniofacial frame in normal occlusion: cephalometric calibration on the vertical axis of coordinates.

ObjectiveThe aim of this study was to evaluate the correlation between the vertical position of maxillary first molar and vertical skeletal measurements in lateral cephalograms by using new linear measurements on the vertical axis of coordinates with calibration.MethodsThe vertical position of maxillary first molar (U6-SN), and the conventionally used variables (ConV) and the newly derived linear variables (NwLin) for vertical skeletal patterns were measured in the lateral cephalograms of 103 Korean adults with normal occlusions. Pearson correlation analyses and multiple linear regression analyses were performed with and without calibration using the anterior and posterior cranial base (ACB and PCB, respectively) lengths to identify variables related to U6-SN.ResultsThe PCB-calibrated statistics showed the best power of explanation. ConV indicating skeletal hyperdivergency was significantly correlated with U6-SN. Six NwLin regarding the position of palatal plane were positively correlated with U6-SN. Each multiple linear regression analysis generated a two-variable model sella and nasion to palatal plane. Among the three models, the PCB-calibrated model yielded highest adjusted R2 value, 0.880.ConclusionsU6-SN could be determined by the vertical position of the maxilla, which could then be used to plan the amount of molar intrusion and estimate its clinical stability. Cephalometric calibration on the vertical axis of coordinates by using PCB for vertical linear measurements could strengthen the analysis itself.

A cross-sectional analysis of Wits and Riedel in adults with skeletal III malocclusion: How informative are they?

To compare the relationship between Riedel and Wits appraisal in skeletal III malocclusions and to assess the effect of variation in the vertical skeletal measurements. One-hundred and twenty consecutive subjects with Class III malocclusions attending orthognathic clinics were analysed. Lateral cephalograms were hand-traced under standardized conditions. Cephalometric measurements included Riedel analysis, Wits appraisal, A point/B point to Frankfurt plane (AF-BF) and vertical measurements. The mean ANB and Wits values were -3.22° and -11.39mm, respectively. A positive correlation was found between ANB and Wits overall (r=-.49; P<.001). However, there was poor agreement between both Wits (r=.087) and Riedel (r=.089) with AF-BF (P>.05). A negative correlation existed between Wits and LAFH% (r=-.64, P-value<.001); however, no relationship was observed between ANB and LAFH% (P>.05) based on linear regression analysis. There is a positive relationship between ANB and Wits; however, neither correlated well with a purer antero-posterior assessment (AF-BF). Furthermore, variations in the vertical skeletal measurements affect the strength of agreement. Caution is advised in the interpretation of antero-posterior analysis especially in the presence of vertical discrepancy.

Influence of nasoalveolar molding on skeletal development in patients with unilateral cleft lip and palate at 5years of age.

The aim of this retrospective study was to assess the influence of presurgical nasoalveolar molding (NAM) on skeletal development in patients with operated unilateral cleft lip and palate at 5years of age. Lateral cephalometric radiographs of 26 unilateral cleft lip and palate patients who had undergone presurgical NAM (NAM group) and 20 unilateral cleft lip and palate patients who did not have any presurgical NAM (non-NAM group) were analyzed. The radiographs were digitally traced using Quick Ceph Studio software (version 3.5.1.r (1151); Quick Ceph Systems, San Diego, Calif). Independent samples t tests were performed for statistical analysis. No significant differences were observed in sagittal and vertical skeletal measurements between the NAM and non-NAM groups. NAM resulted in no significant difference in skeletal development in unilateral cleft lip and palate patients compared with those without NAM in early childhood.

Vertical skeletal changes after extraction and non-extraction treatment in matched class I patients identified by a discriminant analysis: cephalometric appraisal and Procrustes superimposition

BackgroundIn the long-lasting debate of extraction versus non-extraction treatment, the impact of extractions on the skeletal vertical dimension remains rather unclear. The aim of this retrospective research study was to obtain a bias-free sample of morphologically similar borderline patients treated with or without extraction of the four first premolars and to retrospectively evaluate the vertical changes that occurred.MethodsA borderline sample of 83 patients, 41 treated with four first premolar extractions and 42 treated without, was obtained by means of discriminant analysis applied to a previously investigated parent sample of 542 class I patients. The pretreatment and posttreatment cephalometric radiographs were analyzed digitally, and seven measurements were assessed for vertical skeletal changes. Also, average tracings between the two treatment groups were evaluated using the Procrustes superimposition method.ResultsThe variables of SN to Go-Gn and Y-axis showed adjusted intergroup differences of − 0.91° and − 1.11° (P = 0.04). Comparing the mean intra-group differences of all the variables simultaneously, a significant difference was found between the two treatment groups (overall P value = 0.04). In the extraction group, only the gonial angle showed a significant decrease (P = 0.01) while the overall P value evaluating the intra-group differences between pre- and posttreatment was significant (overall P value < 0.01). In the non-extraction group, the variable of N-ANS/N-Me showed a significant decrease (P = 0.02) and the overall P value evaluating the intra-group differences between pre- and posttreatment was also significant (overall P value < 0.01). Differences in treatment duration were assessed using a log-normal model and showed that extraction treatment lasted significantly longer than non-extraction treatment (P < 0.01).ConclusionsThe borderline group of patients identified by the discriminant analysis exhibited similar morphological characteristics at treatment’s onset; therefore, the posttreatment changes could safely be attributed to the choice of extraction or non-extraction treatment and not to pre-existing differences. Treatment choice had an impact on the patients’ vertical skeletal dimensions. Patients treated with four first premolar extractions showed a slight decrease in the vertical skeletal measurements, whereas non-extraction patient treatment showed a slight increase. The treatment time was also significantly higher in the extraction group.

Systematic review and meta-analysis: Mandibular plane change after orthognathic surgery and distraction osteogenesis in cleft lip and palate patients

IntroductionThe aim was to examine treatment change and relapse of mandibular plane in three types of maxillary surgery for cleft patients; (1) conventional orthognathic surgery (CO), (2) extraoral distraction osteogenesis (EDO) and (3) intraoral distraction osteogenesis (IDO). Methods396 abstracts were retrieved from 6 electronic databases; Medline, Embase, Cochrane, ISI, Scopus, and Google Scholar. 138 vertical skeletal measurements of maxillary surgical cleft patients were screened from 141 full-text papers. Finally, only SN-MP at pre-treatment, post-treatment and 1-year follow-up, recruited from 12 articles, were eligible to be investigated by meta-analysis. Heterogeneity test and estimation of pooled means were performed. Difference of SN-MP of the three surgical techniques was examined by 95% confidence interval (CI). ResultsSN-MP at pre-treatment, post-treatment, and follow-up in CO group were 37.8°, 39.9°, 38.5°, in EDO group were 35.1°, 37.5°, 36.8°, in IDO group were 34.2°, 38.2°, 34.6° respectively. All groups demonstrated clockwise rotation of mandible with the estimate change of 2.08°, 2.39° and 3.98° for CO, EDO and IDO respectively. All groups showed counter-clockwise rotation of mandible with the estimate amount of relapse at 1-year follow-up of −1.33°, −0.7°, −3.61° and relapse rate of −63.9%, −29.28% and −90.70% for CO, EDO and IDO respectively. ConclusionsSN-MP showed tendency to rotate clockwise in all three groups after surgery. At 1 year follow-up, the mandibular plane rotated counter-clockwise in all groups. The amount of relapse rate was largest in IDO group. SN-MP at 1 year follow-up in CO was greater than IDO.

Diagnostic features of Angle's Class II div 2 malocclusion.

Statement of Problem:A thorough knowledge of the salient features of malocclusion makes the practitioner to come to a proper diagnosis and to formulate proper mechanotherapy. It also helps to predict the prognosis, prior to the onset of treatment process. Among the various malocclusions, Class II div 2 occurs the least often. The literature review does not clearly describe the classical skeletal and dental features of Angle's Class II div 2 malocclusion.Purpose of Study:The aim of this study is to describe the unique features of Angle's Class II division 2 malocclusion.Materials and Methods:A total of 612 pre-treatment records (study models and cephalograms), with age ranging from 14 to 25 years, were obtained from the hospital records of Drs Sudha and Nageswar Rao Siddhartha Institute of Dental Sciences. Among these samples, 317 were Class II div 1 and 295 were Class II div 2. The lateral cephalograms were analyzed by using Kodak software and the arch width analysis was calculated by using digital vernier calipers.Results:Student's t test was used for the study. On the cephalograms, the vertical skeletal measurements and few of the dental variables showed a significant difference. On the plaster models, the maxillary transverse measurements revealed a notable discrimination between the groups.Conclusion:Angle's Class II div 2 malocclusion has a marked horizontal growth pattern with decreased lower facial thirds, palatally inclined upper anteriors, and remarkably increased transverse maxillary arch dimensions.

Dentoalveolar compensation according to skeletal discrepancy and overjet in skeletal Class III patients

This study was designed to investigate dentoalveolar compensation in untreated skeletal Class III patients with either positive or negative overjet. The positive overjet groups consisted of 104 adults, divided into group 1 (angle between sella-nasion to mandibular plane (SN-MP)> 38°, n= 30), group 2 (30°< SN-MP< 38°, n= 43), and group 3 (SN-MP<30°, n= 31). The negative overjet groups (groups 4-6) consisted of 90 adults who were closely matched to the positive overjet groups with regard to the ANB and SN-MP angles. Twenty-two cephalometric measurements were compared between the matched groups. In the positive overjet groups, correlation analysis was performed between the skeletal and dental measurements, and regression analysis was performed to determine the incisor-mandibular plane angle. The maxillary incisors were more proclined and the occlusal plane was more flattened in the positive overjet groups than in the negative overjet groups; however, there was no statistically significant difference between them with regard to mandibular incisor inclination. The inclinations of the maxillary and mandibular incisors were correlated with both the sagittal and vertical skeletal measurements. Eight regression equations for the incisor-mandibular plane angle were calculated with the highest coefficient of determination of 0.547. Proclination of the maxillary incisors and flattening of the occlusal plane contributed to a positive overjet. Mandibular incisor inclination was more closely associated with sagittal and vertical skeletal discrepancies and was not affected by the incisal relationship.

Dentoskeletal effects of Twin Block and Herbst appliances in patients with Class II division 1 mandibular retrognathy

The aim of this study is to evaluate dentoskeletal effects of Herbst and Twin Block (TB) appliance therapies in Skeletal Class II malocclusion. Herbst group consisted of 11 girls and 9 boys (mean age = 12.74 ± 1.43 years), TB group comprised of 10 girls and 10 boys (mean age = 13.0 ± 1.32 years), and control group included 9 girls and 11 boys (mean age = 12.17 ± 1.47 years). Mean treatment/observation times were 15.81 ± 5.96 months for Herbst, 16.20 ± 7.54 months for TB, and 15.58 ± 3.13 months for control group. Pre-treatment (T0) and post-treatment (T1) lateral cephalograms were traced using a modified Pancherz's cephalometric analysis. Inter-group differences were evaluated with one-way analysis of variance, and intra-group differences were assessed with paired samples t-test at the P < 0.05 level. In control group, all sagittal and vertical skeletal measurements increased as a result of continuing growth. However, skeletal discrepancy and overjet remained unchanged. After functional appliance therapy, greater increases were recorded in TB group for all mandibular skeletal measurements compared with those in control group. Upper dental arch distalization and lower incisor protrusion were significant in Herbst group, compared with control. All face height measurements increased after functional appliance therapy. In TB group, the treatment effects were mainly due to mandibular skeletal changes. Both skeletal and dental changes contribute to Class II correction with Herbst appliance therapy. Herbst appliance may be especially useful in Skeletal Class II patients with maxillary dentoalveolar protrusion and mandibular dentoalveolar retrusion, whereas TB appliance may be preferred for skeletal mandibular retrognathy patients.

Displacement pattern of the maxillary arch depending on miniscrew position in sliding mechanics

This clinical study was performed to evaluate the anteroposterior and vertical displacement patterns of the maxillary teeth in sliding mechanics depending on the position of interradicular miniscrews after the extraction of premolars. Thirty-six women requiring maximum incisor retraction because of bialveolar protrusion were divided into 2 groups: group A (n = 18), miniscrew between the premolar and the molar, and group B (n = 18), miniscrew between the premolars. Cephalometric measurements for skeletal and dental changes were made before and after space closure. In both groups, significant incisor retraction with intrusion of the root apex was noted, with no significant change in the first molar position. Group B displayed significantly greater intrusion at both the incisal tip (1.59 ± 1.53 mm) and the root apex (2.89 ± 1.59 mm) than did group A. In spite of the mean reduction of the vertical skeletal measurements, we failed to find significant skeletal changes. Miniscrews provided firm anchorage for anterior retraction. Selection of the placement site appeared to be an important determinant for the resultant displacement pattern of the incisor segment. Discriminative intrusion or retraction might be obtained via strategic miniscrew positioning.

Nonextraction Treatment with Rapid Maxillary Expansion and Mandibular Symphyseal Distraction Osteogenesis and Vertical Skeletal Dimensions

To investigate the effects of rapid maxillary expansion (RME) and mandibular symphyseal distraction osteogenesis (MSDO) on vertical dimensions of the face. Fourteen patients, nine girls and five boys, underwent RME and MSDO procedures. Distraction was carried out at a rate of 1 mm per 24 hours with a tooth-borne appliance. The amount of distraction was 7 mm for each patient. Standardized lateral cephalograms were taken at the following time periods: before treatment (T0), after RME (T1), at the completion of MSDO (T2), and at the end of fixed orthodontic treatment (T3). The data were evaluated by using a general linear model of repeated-measures analysis of variance and paired t-tests at the 95% confidence level. RME significantly increased the vertical dimensions of the face and decreased the overbite (P < .001). Although the vertical parameters of the face on the lateral cephalogram decreased after MSDO, these decreasing effects were statistically insignificant just for the distances measured from the horizontal reference line to the chin points. In other words, MSDO decreased the vertical skeletal dimensions that were increased by RME, but this neutralizing effect of MSDO was not as much as the increase caused by RME. Treatment modalities (RME, MSDO, and fixed orthodontic treatment) described in this study, in total, had little effect on the vertical skeletal measurements of the face.