A randomized clinical trial comparing mandibular incisor proclination produced by fixed labial appliances and clear aligners

Objective:To compare the mandibular incisor proclination produced by fixed labial appliances and third generation clear aligners.Materials and Methods:Patients underwent a course of orthodontic treatment using either fixed labial appliances or clear aligners (Invisalign). Mandibular incisor proclination was measured by comparing pretreatment and near-end treatment lateral cephalograms. Eligibility criteria included adult patients with mild mandibular incisor crowding (<4 mm) and Class I skeletal bases (ANB, 1–4°). The main outcome was the cephalometric change in mandibular incisor inclination to the mandibular plane at the end of treatment. Eligible patients picking a sealed opaque envelope, which indicated their group allocation, was used to achieve randomization. Data was analyzed using a Welch two-sample t-test.Results:Forty-four patients (mean age, 26.4 ± 7.7 years) were randomized in a 1:1 ratio to either the fixed labial appliance or the clear aligner group. Baseline characteristics were similar for both groups: Fixed appliance mean crowding was 2.1 ± 1.3 mm vs clear aligner mean crowding, 2.5 ± 1.3 mm; pretreatment mean mandibular incisor inclination for the fixed appliance group was 90.8 ± 5.4° vs 91.6 ± 6.4° for the clear aligner group. Fixed appliances produced 5.3 ± 4.3° of mandibular incisor proclination. Clear aligners proclined the mandibular incisors by 3.4 ± 3.2°. The difference between the two groups was not statistically significant (P > .05).Conclusion:There was no difference in the amount of mandibular incisor proclination produced by clear aligners and fixed labial appliances in mild crowding cases.     

Stability of anterior open bite nonextraction treatment in the permanent dentition.

This study cephalometrically evaluated the long-term stability of anterior open bite nonextraction treatment in the permanent dentition after a mean period of 5 years. The experimental group consisted of 21 patients who had undergone orthodontic treatment with fixed appliances from whom cephalometric headfilms were obtained at the pretreatment, posttreatment, and postretention stages. Two control groups were used. The first, with ages comparable with the experimental group before treatment, was used only to characterize it. The second control group, with normal occlusion, was longitudinally followed for a period comparable with the posttretention period and was used to compare the changes between groups during this period. The differences between the observation stages in the experimental group were analyzed with paired t tests, and the postretention changes were compared with the changes of the second control group with independent t tests. A statistically significant decrease of the obtained anterior overbite was demonstrated at the end of the postretention period. The primary factor that contributed to the overbite decrease was the smaller vertical development of the maxillary and mandibular incisors in the postretention period. Neither the pretreatment anterior open bite amount nor the magnitude of correction was associated with the long-term overbite decrease. However, 61.9% of the sample had a clinically stable open bite correction.     

Prediction of mandibular movement and its center of rotation for nonsurgical correction of anterior open bite via maxillary molar intrusion

Objectives:To evaluate quantitatively the relationship between molar intrusion (change [Δ] maxillary first molar [U6]–palatal plane [PP]) and changes in vertical and sagittal cephalometric parameters and to determine the center of mandibular autorotation.Materials and Methods:Twenty-one patients diagnosed with anterior open bite and successfully treated with molar intrusion (overbite [OB] > 0 mm) were retrospectively enrolled. Lateral cephalograms taken before and after molar intrusion were used to measure changes in vertical and sagittal cephalometric parameters. The center of mandibular autorotation was calculated by measuring displacement of gonion (Go) and pogonion (Pog). Paired t-tests were used to compare variables, and linear regression analysis was used to examine the relationship between ΔU6-PP and other variables.Results:The mandible exhibited counterclockwise rotation after maxillary molar intrusion, which led to closure of anterior open bite. Strong linear relationships, in descending order, between ΔU6-PP and ΔOB, Δanterior facial height (AFH), Δvertical reference plane (Pog), and Δsella-nasion to Go-menton (SN-GoMe), were observed. When the maxillary molar was intruded 1 mm, OB increased by 2.6 mm, AFH decreased by 1.7 mm, Pog moved forward by 2.3 mm, and SN-GoMe decreased by 2°. The center of mandibular autorotation was located 7.4 mm behind and 16.9 mm below condylion after molar intrusion.Conclusions:The mandible exhibited counterclockwise rotation after maxillary molar intrusion; the center of mandibular autorotation was located behind and below condylion with individual variations.     

Effects of palatal crib and bonded spurs in early treatment of anterior open bite: A prospective randomized clinical study

Objective:To evaluate the overbite correction of fixed palatal crib (FPC) and bonded lingual spur (BLS) in the early treatment of anterior open bite (AOB) in mixed dentition (primary outcome) as well as its influence on dental and skeletal cephalometric measurements (secondary outcome).Materials and Methods:The selected patients had AOB and a mean age of 8.23 years. They were divided into the following three groups by casting lots: control (n  =  13), palatal crib (n  =  13), and spur (n  =  13). Data from the lateral teleradiography was obtained at the beginning, at 6 months, and after 1 year. The cephalometric analysis was performed by Cef-X program, recording the values of SNA, SNB, ANB, SnG oGn, 1.PP, IMPA, nasolabial angle, overbite, and overjet. Intergroup and intragroup comparisons were obtained via one-way analysis of variance.Results:The degree of AOB was similar at baseline (P > .05). At 6 months and then after 1 year all groups showed improvement in the overbite. However, only the crib and spur groups showed positive overbite. No cephalometric measurements changed significantly over the period analyzed.Conclusions:We conclude that the FPC and BLS are simple and effective for the treatment of anterior open bite, with the advantage given to the FPC.     

Nonsurgical treatment of skeletal anterior open bite in adult patients: Posterior build-ups

Objective:To (1) evaluate the efficacy of build-ups in the correction of anterior open bite in adults, (2) evaluate their efficacy in producing molar intrusion, (3) analyze skeletal and dental changes, and (4) assess the long-term stability.Materials and Methods:The sample consisted of 93 lateral cephalograms from 31 patients with skeletal and dental anterior open bite. The patients had received orthodontic treatment consisting of bonded resin blocks on the maxillary molars combined with Tip-Edge Plus bracket appliances. Cephalometric measurements were performed on radiographs taken before treatment (T1), after treatment (T2), and after a retention period (T3), which were analyzed and compared.Results:Significant dental and skeletal changes were observed after treatment. Molar intrusion averaging 1 mm; 1.44 and 1.57 mm extrusion of mandibular and maxillary incisors, respectively; and a mean of 3.98 mm overbite increase were observed. The mandibular plane angle showed a mean closure of 1.19°, and there was a mean decrease in anterior facial height of 0.7 mm. A mild relapse tendency was observed, but long-term stability was acceptable.Conclusions:Build-ups are an effective treatment alternative for anterior open bite in adults. Outcomes remain significantly stable during the retention period.     

Nonsurgical treatment of a hyperdivergent skeletal Class III patient with mini-screw–assisted mandibular dentition distalization and flattening of the occlusal plane

Treatment of hyperdivergent skeletal Class III malocclusion is challenging for orthodontists, and orthognathic-orthodontic treatment is usually required. This report presents the successful nonsurgical treatment of a 20-year-old man who had a skeletal Class III malocclusion with anterior open bite, anterior and posterior crossbite, hyperdivergent growth pattern, steep occlusal plane, early loss of three first molars, and an uncommon convex profile with a retruded chin. An orthodontic camouflage treatment plan was chosen based on the etiology and the patient''s complaints. Tooth #37 was extracted. Miniscrews were used for uprighting and intruding of the lower molars, distalization of the lower dentition, and flattening of the occlusal plane. After 34 months of active treatment, Class I relationships, proper anterior overjet and overbite, flat occlusal plane, and an esthetic facial profile were achieved. The results demonstrated that the biomechanics involved in the nonsurgical treatment assisted with miniscrews to distalize the mandibular dentition and flatten the occlusal plane while keeping the mandibular plane stable was effective for treating this hyperdivergent skeletal Class III patient with a convex profile and anterior open bite.     

A cephalometric comparison of black open-bite subjects and black normals

Orthodontic surveys of the adolescent and adult population of the United States have shown that the incidence of anterior open bite is three to four times higher in blacks than in whites. A cephalometric comparison of black subjects with and without an open bite was used to identify skeletal and dental differences between the two groups. Statistically significant differences were found in the vertical skeletal dimensions and incisor proclination. The open-bite group had a significantly longer anterior lower facial height and total facial height. The mandibular plane was rotated down relative to the cranial base and Frankfort plane and gonial angle was increased in the open-bite sample. There were small differences between the open bite and non-open-bite groups in the cranial base angle and the overbite depth indicator of Kim. No significant differences were found in the skeletal anteroposterior dimensions or dental vertical development. The vertical skeletal pattern and the greater degree of dental proclination differentiated black patients with an anterior open bite from those without.     

Effect of clear aligner therapy on the buccolingual inclination of mandibular canines and the intercanine distance

Objective:To compare the changes in buccolinugal inclination of mandibular canines and intercanine distance in patients treated with clear aligners to those treated with preadjusted edgewise appliances.Materials and Methods:The buccolingual inclination of mandibular canines and the intercanine distance were measured on pre- and posttreatment cone-beam computed tomograms of 30 patients who had been treated with clear aligners and 30 patients who had been treated with fixed preadjusted edgewise appliances. Differences between the aligner and fixed appliance groups and between pre- and posttreatment measurements were tested for statistical significance.Results:In both groups, most of the mandibular canines had positive buccolingual inclinations (ie, their crowns were positioned lateral to their roots) both before and after treatment. While there was no difference between the groups pretreatment, the posttreatment buccolingual inclination was significantly greater in the aligner group. In the fixed appliance group, the canines became more upright with treatment, while the buccolingual inclination did not change significantly in the clear aligner group. The intercanine distance did not differ between the groups either before or after treatment. However, it increased significantly over the course of treatment in the aligner group, whereas it did not change significantly in the fixed appliance group.Conclusions:Orthodontic treatment with clear aligners tends to increase the mandibular intercanine distance with little change in inclination in contrast to treatment with fixed appliances, which leaves the intercanine distance unchanged but leads to more upright mandibular canines.     

Treatment changes of hypo- and hyperdivergent Class II Herbst patients

Objectives:To determine the relative effects of Herbst appliance therapy in hypo- and hyperdivergent patients.Materials and Methods:The treated group included 45 growing Class II, division 1, patients treated with stainless steel crown Herbst appliances, followed by fixed edgewise appliances. The untreated control group consisted of 45 Class II, division 1, subjects, matched to the treated sample based on Angle classification, age, sex, and pretreatment mandibular plane angle (MPA). Subjects were categorized as hypo- or hyperdivergent based on their MPAs. Pre- and posttreatment cephalograms were traced and superimposed on cranial base and mandibular structures.Results:The primary effect of the Herbst in terms of maxillomandibular correction was in the maxilla. It significantly restricted maxillary growth, producing a “headgear effect.” Mandibular treatment changes depended on divergence. Hyperdivergent patients experienced a deleterious backward true mandibular rotation with Herbst treatment. Hypodivergent patients, as well as untreated hypo- and hyperdivergent controls, underwent forward true mandibular rotation. However, hypodivergent chins did not advance any more than expected for untreated hypodivergent Class II patients.Conclusions:Hypo- and hyperdivergent patients benefit from the Herbst''s headgear effect. While the mandibular growth of hypodivergent patients overcomes the negative rotational effects, hyperdivergent patients undergo a deleterious backward mandibular rotation and increases in facial height.     

Dentoalveolar compensation in Iranian adult skeletal open bite subjects

PurposeThe aim of present study was to compare skeletal and dentoalveolar features of compensated and noncompensated adult open bite subjects with each other and also with those of control group.Materials and methodsA total of 100 lateral cephalograms were included in the study and were divided according to skeletal vertical characteristics into two groups: control group (CG) and open bite group (OBG). The OBG further divided into two subgroups based on amount of overbite: dentally compensated open bite group (COBG) and non compensated open bite group (NCOBG). Twenty skeletal and dentoalveolar variables were evaluated and compared between OBG and CG and also between open bite subgroups by means of Student t-test. Association between different variables and overbite was assessed using Pearson's correlation coefficient.ResultsIncreased molar and incisor height in both jaws were observed in OBG compared to CG. In NCOBG lower anterior facial height and lower posterior dentoalveolar height were significantly higher than COBG.ConclusionDentoalveolar compensatory mechanisms in skeletal open bite patients consist of increased anterior and posterior dentoalveolar heights in upper and lower jaws compared to CG, while decreased mandibular molar height and shorter anterior face height are the most important determinants of adequate compensation in skeletal open bite subjects in our sample.     

Cephalometric changes during treatment with the open bite bionator.

Lateral cephalometric radiographs of 39 patients who were treated with an open bite bionator, also known as a "bionator to close the bite," were obtained from six private orthodontic practices. Comparisons of pretreatment cephalometric values with published standards indicate that clinicians do not generally use this appliance for patients who have marked excessive anterior vertical dimension. Rather, the cases appear to be Class II with mild anterior open bites or with some indication of open bite tendency, such as a steep mandibular plane angle. Changes in cephalometric values during treatment with the appliance were compared with normal growth standards. Patients exhibited a reduction in facial convexity and overjet, reduced eruption of maxillary molars, and less of an increase in facial height than expected. The appliance appears to be effective for Class II correction in patients who require control or improvement of moderately excessive vertical dimension.     

Anterior maxillary dentoalveolar and skeletal cephalometric factors involved in upper incisor crown exposure in subjects with Class II and III skeletal open bite

Objective:To compare the anterior dentoalveolar and skeletal maxillary cephalometric factors involved in excessive upper incisor crown exposure (UICE) in subjects with skeletal open bite Class II (SOBCIIG) and Class III (SOBCIIIG) against an untreated control group (CG).Materials and Methods:Seventy pretreatment lateral cephalograms of orthodontic young adult patients (34 men, 36 women) were examined. The sample was divided into three groups according to both sagittal and vertical growth pattern and occlusion. The CG group (n  =  25) included Class I, normodivergent cases with adequate overbite, and the SOBCIIG group (n  =  25) and SOBCIIIG group (n  =  20) included skeletal Class II or III malocclusions, respectively, with hyperdivergent pattern and negative overbite. Several cephalometric measurements were considered (skeletal and dental). Analysis of variance, multivariate analysis of covariance, and Tukey HSD post hoc tests were used. Principal component analysis (PCA) was used for reducing the number of cephalometric variables related to UICE. Finally, a multiple linear regression was calculated.Results:Significant differences in UICE were found between the groups (P < .05). UICE was 3.9 mm in SOBCIIG, 2.5 mm in SOBCIIIG, and 0.4 mm in CG. PCA showed that a nondental component—including vertical maxillary height (VMH) and upper lip height (ULH)—was the only component significantly associated with UICE. The regression model had a moderate prediction capability.Conclusions:Although the UICE was statistically different in SOBCIIG, the values were within the esthetic standards. The UICE was mainly influenced by VMH and ULH.     

Dimensional changes of dental arches produced by fixed and removable palatal cribs: A prospective,randomized, controlled study

Objective:To evaluate the dimensional changes of dental arches on digital models of open bite treatment with fixed and removable palatal cribs.Materials and Methods:The sample comprised 41 patients of both sexes who were white, aged 7–10 years, and who had mixed dentition, Angle Class I molar relationship, and a negative overbite of at least 1 mm. The sample was randomly divided into two groups: G1, fixed palatal crib; and G2, removable palatal crib. Cast models, obtained initially (T1) and after 1 year of treatment (T2), were scanned by a three-dimensional (3D) scanner, 3Shape R700, producing a 3D image. Measurements were performed by a calibrated examiner using OrthoAnalyzer™ 3D software.Results:At T2–T1, differences were observed between the groups regarding vertical dentoalveolar development and overjet. There was more mandibular incisor extrusion for G1 (−1.66 mm) than for G2 (−0.54 mm). An overjet increase was observed in G1 (0.56 mm), in contrast to a reduction in G2 (−0.40 mm). There was a similar overbite increase for both groups (3.51 mm for fixed palatal crib and 3.88 mm for removable palatal crib).Conclusions:Both the treatment protocols are similarly effective for anterior open bite correction, providing an overbite increase with dentoalveolar arch changes, especially in the anterior region.     

Long-term stability of anterior open bite extraction treatment in the permanent dentition.

The purpose of this study was to cephalometrically evaluate the long-term stability of anterior open bite extraction treatment in the permanent dentition after a mean period of 8.35 years. Cephalometric headfilms were obtained at pretreatment, posttreatment, and postretention stages from 31 patients who had undergone orthodontic treatment with fixed appliances. Two control groups were used. The first, with an age similar to that of the experimental group before treatment, was used only to characterize it. The second, with normal occlusion, was followed longitudinally for a period comparable with the posttreatment period and was used to compare changes during this period. The differences between the observation stages in the experimental group were analyzed with paired t tests, and the posttreatment changes were compared with the changes of the second control group with independent t tests. There was no statistically significant decrease of the obtained anterior overbite at the end of the posttreatment period. The primary factors that contributed to the nonsignificant decrease of the overbite were the normal vertical development of the maxillary and mandibular incisors, the smaller vertical development of the mandibular molars, and the consequent smaller increase in lower anterior face height, as compared with the control group in the long-term posttreatment period. Additionally, 74.2% of the sample had a "clinically stable" open bite correction.     

Evidence of correction of open bitemalocclusion using active vertical corrector treatment

This study used a cephalometric analysis that isolated tipping and bodily tooth movements of the upper and the lower incisors and measured vertical skeletal changes in the anterior region of the maxilla and mandible to evaluate the outcome of two-phase nonextraction treatment for open bite malocclusion. Twenty-nine subjects treated with an active vertical corrector (AVC) followed by fixed 022 orthodontic appliances were selected by one orthodontist from his private practice. All subjects lacked vertical incisor contact at the start of treatment and had adequate initial, end of phase 1, and deband lateral cephalograms. Each subject in the treated group was matched by age and sex with an untreated subject from the Broadbent Bolton Collection, Cleveland, OH. Data were collected for three time intervals; phase 1 treatment with the AVC (T1 to T2), phase 2 fixed-appliance treatment (T2 to T3), and over the total treatment period (T1 to T3). Analysis of the data showed no statistically significant (P < or = .002) changes between treated subjects and controls for any variables during the phase 1 (T1 to T2) or phase 2 (T2 to T3) treatment intervals. However, overbite was significantly improved compared with controls (P < or = .002) during the T1 to T3 time interval. It was concluded that two-phase treatment with the AVC followed by fixed orthodontic appliance treatment results in a statistically significant increase in incisor overbite. The observed increase in overbite was the result of small but clinically significant changes in relative mandibular vertical growth, bodily incisor movement toward the occlusal plane, and lingual tipping of the lower incisors.     

上前牙舌侧粘着式固定平导矫治深覆（牙合）的新探索

目的 探讨固定矫治器配合上切牙舌侧粘着式固定平导矫治深覆（牙合）患者的临床效果.方法 选择均角或低角Ⅲ度深覆（牙合）患者12例作为实验组,男6例,女6例,年龄12～30岁,平均17岁,拔牙9例,非拔牙3例.采用直丝弓固定矫正器治疗,配合制作上前牙舌侧粘着式固定平导辅助打开咬合.选择与实验组相匹配的12例患者作为对照组,对照组患者单纯使用固定矫正器治疗.当覆（牙合）打开后,制取模型,进行治疗前及咬合打开后模型测量分析,分析咬合打开量及所需时间.结果 模型测量结果显示：上颌舌侧固定平导辅助打开咬合效果明显,覆（牙合）平均减小3.37 mm,覆（牙合）打开的平均时间为3.75个月,明显短于对照组.结论 上切牙舌侧粘着式固定平导对于深覆（牙合）患者的矫治非常有效,而且制作简单,有利于口腔卫生,正畸治疗整个过程均不受影响,值得临床推广.     

A case of anterior open bite with severely narrowed maxillary dental arch and hypertrophic palatine tonsils

Abstract

This case report describes an adolescent patient with an open bite and severely narrowed maxillary dentition and hypertrophic palatine tonsils, treated efficiently with rapid maxillary expansion (RME) and subsequent orthodontic tooth alignment using fixed appliances. The treatment demonstrates that RME can be effective for the correction of a severely narrowed maxillary arch, as well as, in this case, the correction of an anterior open bite in an adolescent patient where no substantial vertical skeletal discrepancy existed.     

Multiloop edgewise archwire treatment for a patient with a severe anterior open bite and amelogenesis imperfecta

Amelogenesis imperfecta is a rare hereditary disorder that affects dental enamel and is often associated with an anterior open bite. Orthodontic treatment of a 16-year-old female patient with hypocalcified amelogenesis imperfecta and a 9-mm anterior open bite was presented. Radiographic examination revealed a steep mandibular plane angle, an increased lower face height, a Class II skeletal pattern, and a convex profile. Additionally, the patient had stainless steel crowns on all upper and lower posterior teeth and composite veneers on the upper anterior teeth. The patient was treated nonsurgically using a multiloop edgewise archwire (MEAW). MEAW mechanics allowed for successful correction of the anterior open bite, with significant reduction in the mandibular plane angle and improvement in the patient''s profile. No fixed retainers were used, and the results remained stable 78 months after removal of orthodontic appliances. MEAW mechanics should be considered for patients with large anterior open bites, although this technique requires excellent patient compliance.     

Dentoskeletal effects produced by a Jasper Jumper with an anterior bite plane

Objective:The aim of this retrospective study was to evaluate the dentoskeletal effects produced by a modified Jasper Jumper with an anterior bite plane for the correction of Class II division 1 malocclusion.Materials and Methods:A sample of 32 growing patients (mean age  =  11.9 ± 1.4 years) with Class II division 1 malocclusion and increased overbite were treated with a modified Jasper Jumper (JJ) and anterior bite plane protocol and compared with a matched control group of 30 subjects with untreated Class II malocclusion (mean age 12.2 ± 0.8 years). Lateral cephalograms were taken before treatment (T1) and at the end of comprehensive treatment (T2). Mean treatment duration was 2.1 ± 0.4 years. The T1–T2 changes in the two groups were compared with Student’s t-tests for independent samples.Results:The JJ group was successfully treated to a Class I occlusal relationship with a significant reduction in overjet (–3.9 mm, P < .001) and overbite (–3.1 mm, P < .001). The JJ group exhibited a significant increase in mandibular length and a significant improvement in maxillomandibular sagittal skeletal relationships. The lower incisors were significantly proclined, while the lower first molars demonstrated significant movement in a mesial direction.Conclusions:Use of a modified JJ appliance and anterior bite plane is an effective protocol for the treatment of Class II malocclusion with increased overbite and greater skeletal (75%) than dentoalveolar (25%) effects mainly at the mandibular level.     

Long-term evaluation of rapid maxillary expansion and bite-block therapy in open bite growing subjects: A controlled clinical study

Objective:To evaluate the long-term effects of rapid maxillary expansion (RME) and posterior bite block (BB) in prepubertal subjects with dentoskeletal open bite.Materials and Methods:The treatment group (TG) comprised 16 subjects (14 girls, 2 boys) with dentoskeletal open bite with a mean age of 8.1 ± 1.1 years treated with RME and BB. Three consecutive lateral cephalograms were available before treatment (T1), at the end of the active treatment with the RME and BB (T2), and at a follow-up observation at least 4 years after the completion of treatment (T3). The TG was compared with a control group (CG) of 16 subjects (14 girls, 2 boys) matched for sex, age, and vertical skeletal pattern. An independent sample t-test was used to compare the T1 to T3, T1 to T2, and T2 to T3 cephalometric changes between the TG and the CG.Results:In the long term, the TG showed a significantly greater increase in overbite (+1.8 mm), reduced extrusion of maxillary and mandibular molars (−3.3 mm), and, consequently, a significant decrease in facial divergence (−2.8°) when compared with untreated subjects.Conclusions:The RME and BB protocol led to successful and stable recovery of positive overbite in 100% of the patients considered. Correction of open bite was associated with reduced extrusion of maxillary and mandibular molars with a significant improvement in vertical skeletal relationships when compared with the CG.