Maxillary anterior alignment stability in Class I and Class II malocclusions treated with or without extraction

Objective:To compare the postretention stability of maxillary incisors alignment in subjects with Class I and II malocclusion treated with or without extractions.Materials and Methods:The sample comprised 103 subjects with initial maxillary anterior irregularity greater than 3 mm and was divided into four groups: group 1 comprised 19 patients with Class I malocclusion treated with nonextraction (mean initial age = 13.06 years); group 2 comprised 19 patients with Class II malocclusion treated with nonextraction (mean initial age = 12.54 years); group 3 comprised 30 patients with Class I malocclusion treated with extractions (mean initial age = 13.16 years); group 4 comprised 35 patients with Class II malocclusion treated with extractions (mean initial age = 12.99 years). Dental casts were obtained at three different stages: pretreatment (T1), posttreatment (T2), and long-term posttreatment (T3). Maxillary incisor irregularity and arch dimensions were evaluated. Intergroup comparisons were performed by one-way analysis of variance followed by Tukey tests.Results:In the long-term posttreatment period, relapse of maxillary crowding and arch dimensions was similar in all groups.Conclusion:Changes in maxillary anterior alignment in Class I and Class II malocclusions treated with nonextractions and with extractions were similar in the long-term posttreatment period.     

Maxillary incisor inclination of skeletal Class III patients treated with extraction of the upper first premolars and two-jaw surgery: Conventional orthognathic surgery vs surgery-first approach

Objective:To investigate the differences in the amount and pattern of the maxillary incisor (MXI) inclination change in skeletal Class III patients treated with extraction of the maxillary first premolars (MXP1) and two-jaw surgery (TJS) between conventional orthognathic surgery (COS) and surgery-first approach (SFA).Materials and Methods:The study included 60 skeletal Class III patients who had normal maxillary position, prognathic mandible, and mild crowding in the maxillary arch (≤4 mm). The patients were divided into group 1 (COS, n  =  36) and group 2 (SFA, n  =  24). Lateral cephalograms were taken before treatment (T0), 1 month before surgery (T1), within 1 month after surgery (T2), and after debonding (T3) for COS patients and at T0, T2, and T3 for SFA patients. After measurement of the skeletodental variables, statistical analyses were performed.Results:During T0–T2, the amount of MXI inclination change (ΔU1-SN) in group 1 was significantly larger than that in group 2 (−12.8° vs −4.4°; P < .001). During T2–T3, ΔU1-SN in groups 1 and 2 occurred in opposite directions (3.8° vs −5.9°; P < .001). However, the total amount of ΔU1-SN during T0–T3 was not different between groups 1 and 2 (−9.0° vs −10.3°). At T3 the U1-SN values for groups 1 and 2, respectively, moved closer to normal according to the values of the normal range rate (all 83%), relative percentage ratio (102.4% and 100.1%), and achievement ratio (77.7% and 97.8%).Conclusions:The results of this study might provide basic data for predicting the amount and pattern of MXI inclination change in SFA for skeletal Class III TJS patients.     

The Class II Carriere Motion appliance:: A 3D CBCT evaluation of the effects on the dentition

ObjectivesTo determine three-dimensional treatment changes produced by the Class II Carriere Motion appliance (CMA) in Class II adolescent patients with Class I and Class II skeletal relationships.Materials and MethodsThe sample included 59 adolescents (16 boys and 43 girls) with unilateral or bilateral Class II molar and bilateral Class II canine relationship. They were divided into group 1 with skeletal Class I (N = 27; ANB 2.90° ± 1.40°; 13.30 ± 1.53 years) and group 2 with skeletal Class II (N = 32; ANB 6.06° ± 1.64°; 13.26 ± 1.76 years). Cone beam computed tomography images were traced with Invivo software pretreatment (T1) and post-CMA usage (T2). The treatment changes in 36 measurements were calculated in each group, and the changes in 16 measurements were compared between them.ResultsIn group 1 and 2, maxillary first molars underwent significant distal movement (1.92 mm ± 0.80 mm and 1.67 mm ± 1.56 mm, respectively) with distal tipping and rotation, maxillary canines underwent significant distal movement (2.34 mm ± 1.07 mm and 2.24 mm ± 1.91 mm, respectively) with distal tipping and rotation, and mandibular molars underwent significant mesial movement (–1.37 mm ± 1.23 mm and –2.51 mm ± 1.51 mm, respectively) with mesial tipping. Between the groups, there were significant differences in mandibular molar mesial movement and the U1-SN changes (P < .05).ConclusionsThe CMA corrected Class II malocclusion through distal tipping and rotational movement of maxillary canines and molars and corrected mesial tipping of mandibular molars. Significantly more mandibular molar mesial movement and maxillary incisor flaring were observed in patients with skeletal Class II.     

Asymmetric rapid maxillary expansion in true unilateral crossbite malocclusion: A prospective controlled clinical study

Objective:To investigate the short-term effects of the asymmetric rapid maxillary (ARME) appliance on the vertical, sagittal, and transverse planes in patients with true unilateral posterior crossbite.Materials and Methods:Subjects were divided into two groups. The treatment group was comprised of 21 patients with unilateral posterior crossbite (mean age  =  13.3 ± 2.1 years). Members of this group were treated with the ARME appliance. The control group was comprised of 17 patients with Angle Class I who were kept under observation (mean age  =  12.3 ± 0.8 years). Lateral and frontal cephalograms were taken before the expansion (T1), immediately after expansion (T2), and at postexpansion retention (T3) in the treatment group and at preobservation (T1) and postobservation (T2) in the control group. A total of 34 measurements were assessed on cephalograms. For statistical analysis, the Wilcoxon test and analysis of covariance were used.Results:The ARME appliance produced significant increases in nasal, maxillary base, upper arch, and lower arch dimensions (P < .01) and a clockwise rotation of the occlusal plane (P  =  .001).Conclusion:The ARME appliance created asymmetric increments in the transversal dimensions of the nose, maxilla, and upper arch in the short term. Asymmetric expansion therapy for subjects with unilateral maxillary deficiency may provide satisfactory outcomes in adolescents, with the exception of mandibular arch expansion. The triangular pattern of expansion caused clockwise rotation of the mandible and the occlusal plane and produced significant alterations in the vertical facial dimensions, whereas it created no displacement in maxilla in the sagittal plane.     

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.     

Mandibular rotation during the transitional dentition

Objective:To determine whether dentoalveolar changes or vertical condylar growth is more closely related to the true forward rotation of the mandible during the transition between the late primary and early mixed dentition stages of development.Materials and Methods:The sample included 50 subjects (25 males and 25 females) with Class I (N  =  25) and Class II (N  =  25) molar relationships. They were selected based on the availability of lateral cephalograms at two developmental stages: T1: last film with complete primary dentition (5.8 ± 0.4 years) and T2: first film with permanent incisors and permanent molars fully erupted (8.0 ± 0.2 years). Seventeen landmarks were identified and 22 measurements were calculated. The mandibles at T1 and T2 were superimposed using natural reference structures in order to measure true mandibular rotation.Results:The mandible underwent −2.4° ± 2.6° of true rotation, 1.9° ± 2.4° of remodeling, and −0.6° ± 1.8° of apparent rotation. There were no significant sex or Class differences in true rotation, remodeling, and apparent rotation. There was a moderate correlation (r  =  0.76) between true rotation and remodeling and a moderately low correlation (r  =  0.40) between true rotation and apparent rotation. There was a weak correlation between true rotation and SNA (r  =  0.28). True rotation was most closely associated with the increases in U1/S-N (r  =  −0.34), increases in U1/PP (r  =  −0.36), and decreases in Id-Me (r  =  0.36).Conclusions:Independent of sex and Class, the true mandibular rotation that occurred between the late primary and early mixed dentition was mostly masked by angular remodeling, resulting in limited amounts of apparent rotation. True rotation was significantly related to anterior dentoalveolar changes but not to the vertical growth changes that occurred.     

Response of the maxillary dentition to a statically determinate one-couple system with tip-back mechanics: A prospective clinical trial

Objective:To quantify the effects of tip-back mechanics on the maxillary first molars and incisors.Materials and Methods:Sixteen subjects with Class II end-on malocclusion were treated with an intrusion arch to achieve distalization of the maxillary molar through tip-back mechanics. Lateral cephalograms were taken prior to molar tip-back (T1), after molar tip-back (T2), and after molar root uprighting (T3). Data were analyzed using the Friedman’s and Wilcoxon signed rank tests to evaluate differences in time points (P ≤ .016).Results:The maxillary first molar distalized 1.53 mm (P = .001) with 6.65° (P = .001) of distal tipping and 0.86 mm (P = .001) of extrusion at T2. Minor relapse of the first molar (mesial direction) was seen at T3. The maxillary incisors flared labially 0.4 mm, and the incisor root apex moved palatally 1.19 mm (P = .005) at T2. At T3, the incisor root apex moved palatally 1.5 mm (P = .003) from T1. An angular change from T1 of 3.31° (P = .008) and 3.53° (P = .014) was seen at T2 and T3, respectively, as a result of palatal root movement of the maxillary incisors.Conclusions:A significant amount of distalization of maxillary molars was attained at the crown level with tip-back mechanics. Palatal root angulation change was significant in the incisors with minimal anteroposterior movement of the incisal edge.     

The short-term treatment effects of face mask therapy in Class III patients based on the anchorage device: Miniplates vs rapid maxillary expansion

Objective:To compare the short-term treatment effects of face mask therapy with miniplates (FM-MP) and face mask therapy with rapid maxillary expansion appliance (FM-RME) in growing Class III malocclusion patients with maxillary hypoplasia.Materials and Methods:Twenty patients were allocated into two groups according to the anchorage device: FM-MP group (n  =  10; mean age  =  11.2 ± 1.2 years; miniplates in the zygomatic buttress area) and FM-RME group (n  =  10; mean age  =  10.7 ± 1.3 years; bonded or banded RME). The face mask was applied for 12 to 14 hours/day in both groups with a force of 400 g/side directed 30° downward and forward from the occlusal plane. Lateral cephalograms were taken before (T1) and after FM-MP or FM-RME therapy (T2). Skeletodental and soft-tissue variables were measured. Paired and independent t-tests were performed for statistical analysis.Results:Both groups exhibited significant forward movement of point A and posterior repositioning and opening rotation of the mandible from T2 to T1. The FM-MP group showed significant protraction of orbitale (ΔSNO), and the FM-RME group showed a decrease in overbite and an increase in Björk sum. Comparing the amount of changes between the two groups, the FM-MP group displayed greater forward movement of the maxilla than the FM-RME group (ΔSNA, ΔA to N perp, all P < .05). However, the FM-RME group exhibited a greater opening rotation of the mandible (ΔSNB, Björk sum, all P < .01; ΔPog to N-perp, P < .05) and labioversion of the maxillary incisors (ΔU1-FH, P < .05).Conclusion:FM-MP therapy induces a greater advancement of the maxilla, less posterior repositioning and opening rotation of the mandible, and less proclination of the maxillary incisors than FM-RME therapy.     

A prospective controlled evaluation of Class II division 1 malocclusions treated with fixed lingual mandibular growth modificator

Objective: To assess the net dentofacial effects of the fixed lingual mandibular growth modificator (FLMGM).Materials and Methods:The study sample comprised 38 patients with Class II/1 malocclusion and retrognathic mandible. All were in the pubertal growth spurt. Whereas FLMGM was applied to the treatment group (n  =  21, mean age  =  13.2 years), no treatment was performed on the control group (n  =  17, mean age  =  12.5 years). Skeletal and dentoalveolar changes were assessed on digital lateral cephalograms obtained at the beginning and end of the treatment/observation period of 8 months. Paired and independent t-tests were used to assess the differences within and between groups.Results:Maxillary growth was not affected by FLMGM treatment, which resulted in a significant overjet reduction of 4.1 mm, an increase in total mandibular length (Co-Gn) of 2.3 mm, chin advancement of 1.6°, and upper incisor retroclination of 4.0°. A reduction of 2.4° in ANB was largely due to an increase of 1.8° in SNB. Favorably, the lower incisors were obviously retroclined by 4.5°. The changes in the vertical skeletal relationships were negligible.Conclusion:FLMGM was effective in treating growing Class II/1 patients and produced favorable dentofacial effects, with the matched untreated sample showing minimal changes. Lower incisor retroclination was a benefit of FLMGM treatment.     

Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

Objective:To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction.Materials and Methods:Panoramic radiographs of 21 Class II subdivision adolescents (eight boys, 13 girls; mean age, 12.8 years; standard deviation, 1.7 years) before treatment, after treatment with extraction of one maxillary first molar and Begg appliances and after at least 1.8 years in retention were retrospectively collected from a private practice. M2 and M3 inclination angles (M2/ITP, M2/IOP, M3/ITP, M3/IOP), constructed by intertuberosity (ITP) and interorbital planes (IOP), were calculated for the extracted and nonextracted segments. Random effects regression analysis was performed to evaluate the effect on the molar angulation of extraction, time, and gender after adjusting for baseline measurements.Results:Time and extraction status were significant predictors for M2 angulation. M2/ITP and M2/IOP decreased by 4.04 (95% confidence interval [CI]: −6.93, 1.16; P  =  .001) and 3.67 (95% CI: −6.76, −0.58; P  =  .020) in the extraction group compared to the nonextraction group after adjusting for time and gender. The adjusted analysis showed that extraction was the only predictor for M3 angulation that reached statistical significance. M3 mesial inclination increased by 7.38° (95% CI: −11.2, −3.54; P < .001) and 7.33° (95% CI: −11.48, −3.19; P  =  .001).Conclusions:M2 and M3 uprighting significantly improved in the extraction side after orthodontic treatment with unilateral maxillary M1 extraction. There was a significant increase in mesial tipping of maxillary second molar crowns over time.     

A Comparison Study of Upper Airway among Different Skeletal Craniofacial Patterns in Nonsnoring Chinese Children

Objective:Patients with OSAS (obstructive sleep apnea syndrome) demonstrate decreased upper airway dimension and craniofacial skeletal abnormalities. The study was performed to analyze whether upper airway dimensions differed among Chinese nonsnoring children of different sagittal and vertical skeletal facial morphologies.Materials and Methods:Lateral cephalometric records were used to measure the dimensions of the upper airway. Two groups of subjects were studied. A group of subjects with a normodivergent facial pattern (n  =  190; FH-MP angle between 23.5° and 30.5°) was divided into three subgroups according to ANB angle (Class I, II, or III). A second group of subjects with a normal sagittal facial pattern (n  =  180; ANB angle between 0.7° and 4.7°) was divided into three subgroups according to the FH-MP angle (low angle, normal angle, or high angle). All subgroups were matched for age and sex.Results:In the group of subjects with a normodivergent facial pattern, a significant tendency for reduced upper airway dimension in the inferior part (palatopharyngeal and hypopharynx) was found in the Class III, Class I, and Class II subgroups, in that order. In the group of subjects with a normal sagittal facial pattern, the superior part of the airway (nasopharyngeal and palatopharyngeal) decreased with increasing mandibular plane angle.Conclusion:The sagittal and vertical skeletal patterns may be contributory factors for the variation of the inferior and superior part of the upper airway, respectively. Skeletal deficiency of nonsnoring Chinese children may predispose them to upper airway obstruction.     

Evaluation of the splint-supported Forsus Fatigue Resistant Device in skeletal Class II growing subjects

ObjectivesTo evaluate the use of the Forsus Fatigue Resistant Device (FFRD), supported with bimaxillary splints, in treatment of skeletal Class II malocclusion.Materials and MethodsData from 46 skeletal Class II females who received either conventional Forsus alone (FFRD group) (15 patients, 12.54 ± 0.90 years), FFRD and bimaxillary splints (splint-FFRD group) (15 patients, 12.29 ± 0.82 years), or were untreated controls (16 subjects, 12.1 ± 0.9 years) were retrieved from previous clinical trials. FFRD was inserted onto the mandibular archwire in the FFRD group after leveling and alignment with multibracket appliances. In the splint-FFRD group, Forsus was inserted between fixed maxillary and mandibular splints. Treatment continued until reaching an edge-to-edge incisor relationship.ResultsBoth treatment groups failed to induce significant mandibular skeletal effects compared to the normal growth exhibited by untreated controls. The splint-FFRD group showed significant reduction of SNA (−0.88° ± 0.51°) and ANB (−1.36° ± 0.87°). The mandibular incisors showed significant proclination in the FFRD (9.17° ± 2.42°) and splint-FFRD groups (7.06° ± 3.34°).ConclusionsThe newly proposed splint-supported FFRD was equally effective as the conventional FFRD in treatment of Class II malocclusion with dento-alveolar changes and additional maxillary restricting effect. It has an additional advantage of immediate initiation of the Class II correction.     

Malocclusion and treatment need in children and adolescents with sickle cell disease

Objective:To assess the prevalence of malocclusion and treatment need in children and adolescents with sickle cell disease (SCD).Materials and Methods:In this cross-sectional study, the sample size comprised 35 five-year-old children and 36 adolescents of both sexes, aged between 12 to 18 years, with SCD. Dental occlusion was assessed using two indexes: the Malocclusion Index (World Health Organization) and the Dental Aesthetic Index (DAI).Results:The prevalence of malocclusion in the preschool children was 62.9%. The main malocclusions observed in this age group were Class II (37.1%), increased overjet (28.6%), reduced overbite (28.6%), and open bite (17.1%). In the 12- to 18-year-old subjects, the prevalence of malocclusion was 100%, and the most prevalent types of malocclusion were maxillary overjet (63.9%) and maxillary misalignment (58.3%). It is noteworthy that the majority of adolescents (80.6%) had very severe or disabling malocclusions.Conclusion:The results revealed a high prevalence of malocclusion in children and adolescents with SCD. According to DAI score, the majority of the sample presented with very severe malocclusion and a compulsory treatment need.     

Treatment effects of the Forsus Fatigue Resistant Device used with miniscrew anchorage

Objective:To evaluate the dentofacial effects of the Forsus Fatigue Resistant Device (FRD) used with miniscrew anchorage (FRDMS) and compare them with those of conventional FRD and an untreated Class II control group.Materials and Methods:The sample consisted of 48 Class II subjects. Sixteen patients (13.68 ± 1.09 years of age) were treated with FRDMS, whereas 17 subjects (14.64 ± 1.56 years of age) were treated with only FRD. Also, a control sample of 15 untreated Class II subjects (14.13 ± 1.50 years of age) was constructed. Angular and linear measurements were made on 96 lateral cephalograms. Paired t, one-way analysis of variance, and Tukey tests were used for statistical analysis.Results:Class I molar relationship and overjet correction were achieved in an average period of 6.5 ± 1.97 and 5.5 ± 1.80 months in the FRDMS and FRD groups, respectively. No skeletal effect was determined in both treatment groups. Greater overbite correction was found in the FRD group. Retrusion and extrusion of maxillary incisors, distalization of maxillary molars, and extrusion of mandibular molars were significant in both treatment groups. Labial tipping of mandibular incisors was significantly greater in the FRD group than in the FRDMS group.Conclusion:Overjet and molar correction was totally dentoalveolar. Unfavorable labial tipping of mandibular incisors was effectively minimized with the usage of miniscrews.     

Camouflage treatment of skeletal Class III malocclusion with multiloop edgewise arch wire and modified Class III elastics by maxillary mini-implant anchorage

Objective:To evaluate the effect of the multiloop edgewise arch wire (MEAW) technique with maxillary mini-implants in the camouflage treatment of skeletal Class III malocclusion.Materials and Methods:Twenty patients were treated with the MEAW technique and modified Class III elastics from the maxillary mini-implants. Twenty-four patients were treated with MEAW and long Class III elastics from the upper second molars as control. Lateral cephalometric radiographs were obtained and analyzed before and after treatment, and 1 year after retention.Results:Satisfactory occlusion was established in both groups. Through principal component analysis, it could be concluded the anterior-posterior dental position, skeletal sagittal and vertical position, and upper molar vertical position changed within groups and between groups; vertical lower teeth position and Wits distance changed in the experimental group and between groups. In the experimental group, the lower incisors tipped lingually 2.7 mm and extruded 2.4 mm. The lingual inclination of the lower incisors increased 3.5°. The mandibular first molars tipped distally 9.1° and intruded 0.4 mm. Their cusps moved 3.4 mm distally. In the control group, the upper incisors proclined 3°, and the upper first molar extruded 2 mm. SN-MP increased 1.6° and S-Go/N-ME decreased 1.Conclusions:The MEAW technique combined with modified Class III elastics by maxillary mini-implants can effectively tip the mandibular molars distally without any extrusion and tip the lower incisors lingually with extrusion to camouflage skeletal Class III malocclusions. Clockwise rotation of the mandible and further proclination of upper incisors can be avoided. The MEAW technique and modified Class III elastics provided an appropriate treatment strategy especially for patients with high angle and open bite tendency.     

Three-dimensional cone-beam computed tomography comparison of shorty and standard Class II Carriere Motion appliance

ObjectivesTo compare treatment effects of the standard and shorty Class II Carriere Motion appliances (CMAs) on adolescent patients.Materials and MethodsFifty adolescents with Class II malocclusion formed group 1, who were treated with shorty CMA (n = 25, 12.66 ± 1.05 years), and age- and sex–matched group 2, who were treated with standard CMA (n = 25, 12.73 ± 1.07 years). Treatment effects were analyzed by tracing with Invivo software to compare pretreatment (T1) cone-beam computed tomography (CBCT) images with post-CMA (T2) CBCT images. A total of 23 measurements were compared within and between groups.ResultsIn groups 1 and 2, maxillary first molars showed significant distal movement from T1 to T2 (1.83 ± 2.11 mm and 2.14 ± 1.34 mm, respectively), with distal tipping and rotation in group 1 (6.52° ± 3.99° and 3.15° ± 7.52°, respectively) but only distal tipping (7.03° ± 3.45°) in group 2. Similarly, in both groups, the maxillary first premolars experienced significant distal movement with distal tipping but no significant rotation. In group 1, maxillary canines did not undergo significant distal movement. In both groups 1 and 2, mandibular first molars experienced significant mesial movement (1.85 ± 1.88 mm and 2.44 ± 2.02 mm, respectively). Group 1 showed statistically significantly less reduction in overjet and less canine distal movement with less distal tipping than group 2 (α < .05).ConclusionsThe shorty CMA achieved Class II correction similarly to the standard CMA, with less change in overjet and distal tipping movement of the maxillary canines.     

Comparison of transverse analysis between posteroanterior cephalogram and cone-beam computed tomography

Objectives:To evaluate maxillary and mandibular alveolar and basal bone widths using cone-beam computed tomography (CBCT) and to verify the correlation between CBCT images and posteroanterior (PA) cephalograms.Materials and Methods:The CBCT scans and PA cephalograms were obtained from 20 men (age range  =  24.0–29.1 years; mean age  =  27.2 years; SD  =  2.8 years) and 20 women (age range  =  20.3–28.1 years; mean age  =  26.4 years; SD  =  3.2 years) with normal occlusion. On CBCT images, maxillary and mandibular bone widths were measured at three posterior sites and five bone levels. The differences between maxillary and mandibular bone widths were calculated and compared with conventional transverse width of PA cephalograms.Results:Statistically significant differences in maxillary and mandibular bone widths were detected at different levels and sites. Bone widths were significantly increased from the alveolar crest toward the basal bone in the maxillary molar and mandibular second premolar and molar areas. A statistically significant correlation was only found between CBCT images and PA cephalograms for maxillomandibular width at the first molar area.Conclusion:The results of this study suggested that three-dimensional assessment of maxillomandibular width is mandatory for the transverse analysis.     

Long-term evaluation of Class II subdivision treatment with unilateral maxillary first molar extraction

Objective:To evaluate the long-term effects of asymmetrical maxillary first molar (M1) extraction in Class II subdivision treatment.Materials and Methods:Records of 20 Class II subdivision whites (7 boys, 13 girls; mean age, 13.0 years; SD, 1.7 years) consecutively treated with the Begg technique and M1 extraction, and 15 untreated asymmetrical Class II adolescents (4 boys, 11 girls; mean age, 12.2 years; SD, 1.3 years) were examined in this study. Cephalometric analysis and PAR assessment were carried out before treatment (T1), after treatment (T2), and on average 2.5 years posttreatment (T3) for the treatment group, and at similar time points and average follow-up of 1.8 years for the controls.Results:The adjusted analysis indicated that the maxillary incisors were 2.3 mm more retracted in relation to A-Pog between T1 and T3 (β  =  2.31; 95% CI; 0.76, 3.87), whereas the mandibular incisors were 1.3 mm more protracted (β  =  1.34; 95% CI; 0.09, 2.59), and 5.9° more proclined to the mandibular plane (β  =  5.92; 95% CI; 1.43, 10.41) compared with controls. The lower lip appeared 1.4 mm more protrusive relative to the subnasale-soft tissue-Pog line throughout the observation period in the treated adolescents (β  =  1.43; 95% CI; 0.18, 2.67). There was a significant PAR score reduction over the entire follow-up period in the molar extraction group (β  =  −6.73; 95% CI; −10.7, −2.7). At T2, 65% of the subjects had maxillary midlines perfectly aligned with the face.Conclusions:Unilateral M1 extraction in asymmetrical Class II cases may lead to favorable occlusal outcomes in the long term without harming the midline esthetics and soft tissue profile.     

Three-dimensional changes of the naso-maxillary complex following rapid maxillary expansion

Objective:To assess the volumetric changes and the maxillary response of the naso-maxillary complex (NMC) following rapid maxillary expansion (RME).Materials and Methods:Thirty consecutive patients (14 males and 16 females) with a mean age at first observation of 9.5 ± 1.8 years for males and of 11.8 ± 1.7 years for females, presenting a posterior unilateral or bilateral crossbite and requiring RME, were selected for the study. Each patient underwent expansion to correct the transverse occlusal relationships. Computed tomography scans were taken before RME (T1) and at the end of the active expansion phase (T2). Measurements were performed on scanned images. The Kolmogorov-Smirnov test was performed; the mean differences between measurements at T1 and T2 were compared using the t-test (α  =  .05).Results:All volumetric, maxillary, transverse skeletal anterior and posterior variables as well as all dental anterior and posterior linear and angular variables representing the NMC displayed statistically highly significant increases after RME (P < .001).Conclusions:After RME the total volume of the NMC increased by 12%, the nasal volume by 17%, and the maxillary volume by 10.6%. The maxillary and the nasal contributions represented 69.75% and 30.25%, respectively.     

Corticotomy-assisted maxillary protraction with skeletal anchorage and Class III elastics

Objective:To analyze the treatment effects of corticotomy-assisted maxillary protraction with skeletal anchorage and Class III elastics in patients with Class III malocclusions.Materials and Methods:The study group consisted of 19 patients with a mean age of 13.12 ± 1.28 years. Initially, patients were monitored for 5 months before treatment to evaluate growth changes. Changes during control, protraction and fixed orthodontic treatment periods were compared with the cephalometric radiographs taken initially, before protraction, after protraction, and after fixed orthodontic treatment. Treatment outcomes also were compared with the growth effects.Results:Sagittal measurements of maxilla showed significant improvements (3.59 ± 1.32 mm) during the protraction period (3.85 ± 1.12 months) whereas no significant changes were seen during the control period. Upper and lower incisor inclinations were increased, and the upper occlusal plane angle showed significant counterclockwise rotation during protraction. Significant soft-tissue changes also reflected the underlying skeletal changes. Maxillary advancement was stable during fixed orthodontic treatment.Conclusion:Compared with control period of the patients, this protocol produced significant improvements in skeletal and soft-tissue structures.