Tooth sizes in nonsyndromic hypodontia patients

Objective:To evaluate and compare the sizes of teeth in mild and severe hypodontia patients with those of healthy controls.Materials and Methods:Dental casts of 154 patients with two or more congenitally missing teeth were obtained. Patients were divided into two groups according to severity of hypodontia. Group I (mild) consisted of 118 patients with two to five missing teeth. Group II (severe) consisted of 36 patients with six or more missing teeth. In addition, a control group was included, which consisted of 50 patients who had an Angle Class I jaw relationship and no missing teeth. Mesiodistal and labiolingual dimensions of the teeth were measured with a digital caliper on dental casts. The independent-samples t-test was used to evaluate the effect of gender on measurements. Intergroup differences for mesiodistal and labiolingual dimensions were evaluated with analysis of variance and post hoc Tukey tests.Results:Statistically significant differences were found between girls and boys with hypodontia in the mesiodistal dimension of the mandibular first premolar and the labiolingual dimension of the mandibular lateral incisor (P < .01). Mesiodistal and labiolingual width measurements of the teeth of hypodontia patients showed statistically significant differences compared with the control group (P < .05). Most teeth showed significant dimensional reductions in severe hypodontia compared with mild hypodontia (P < .05).Conclusions:The mesiodistal and labiolingual dimensions of teeth in both mild and severe hypodontia groups were smaller than those in control subjects. The reduction in size was more excessive in the severe hypodontia group. The teeth showing the greatest difference in tooth dimensions were the maxillary lateral incisor (in mesiodistal dimension) and the mandibular canine (labiolingual dimension).     

Asymmetric dental arch treatment with Forsus fatigue appliances: Long-term results

Objectives:To investigate the treatment efficacy and follow-up stability of the asymmetric Forsus appliance by evaluating longitudinal changes in dental arch asymmetry on digital dental models from 21 patients.Materials and Methods:Maxillary and mandibular reference lines were used for measurements of intra-arch asymmetry at pretreatment (T1), posttreatment (T2), and 4.2 years after treatment (T3). Maxillary and mandibular measurements were performed relative to the dental midline and anterior reference line on digital dental models. To determine the amount of asymmetry between the Class I and Class II sides of a given arch, all maxillary and mandibular parameters were measured on each side of the model separately. Repeated-measures analysis of variance/paired sample t-tests were performed to evaluate dental arch asymmetries at the P < .05 level.Results:The alveolar transverse dimensions of the posterior segment of both arches were increased during treatment (P < .05) and remained stable during the retention period. Class II subdivision malocclusion was caused by distal positioning of the mandibular canine, premolars, and first molar on the Class II side (P < .05). Asymmetry was resolved by treatment with asymmetric Forsus appliances. The resolved asymmetry remained stable over the long term. There were no significant differences between T2 and T3 (P > .05).Conclusions:The asymmetric Forsus appliance can be used to treat dental arch asymmetry in patients with Class II subdivision malocclusions.     

Effectiveness of twin-block and Mandibular Protraction Appliance-IV in the improvement of pharyngeal airway passage dimensions in Class II malocclusion subjects with a retrognathic mandible

Objective:To test the hypothesis that twin-block and Mandibular Protraction Appliance-IV (MPA-IV) are not effective in improving the pharyngeal airway passage (PAP) dimensions among Class II malocclusion subjects with a retrognathic mandible.Materials and Methods:Eighty-three subjects ranging in age from 8 to 14 years were divided into four groups. Group I included 30 Class I malocclusion subjects (healthy controls); group II consisted of 16 Class II malocclusion subjects (Class II controls); group III had 16 subjects in whom Class II malocclusion was treated by MPA-IV; and the remaining 21 subjects formed group IV, whose Class II malocclusions were corrected by twin-block appliance. Lateral cephalograms recorded at the beginning of orthodontic treatment in group I subjects and at the beginning and end of follow-up/treatment with functional appliance in group II, III, and IV subjects were analyzed to determine the PAP dimensions. Paired t-test, one-way analysis of variance, and Tukey tests were applied for statistical analysis, and a P-value .05 was considered statistically significant.Results:Soft palate length was decreased significantly in group III (P < .05) and group IV (P < .001) subjects. Soft palate thickness in group IV subjects was increased significantly as compared to group II (P < .05) and group III (P < .01) subjects. The improvement in soft palate inclination in group III and group IV subjects was significant (P < .01). The oropharynx depth was increased significantly in group III (P < .05) and group IV (P < .001) subjects. The depth of the hypopharynx was increased significantly (P < .01) in group IV subjects.Conclusions:The twin-block appliance was more efficient than the MPA-IV in the improvement of PAP dimensions among Class II malocclusion subjects with retrognathic mandible.     

Initial growth pattern of children with cleft before alveolar bone graft stage according to cleft type: Unilateral cleft lip and alveolus,unilateral cleft lip and palate,and cleft palate

Objective:To test the null hypothesis that there is no significant difference in the initial growth pattern among three cleft types before alveolar bone graft (ABG) according to cleft type (unilateral cleft lip and alveolus [UCLA], unilateral cleft lip and palate [UCLP], and cleft palate [CP]).Materials and Methods:Samples consisted of the UCLA group, the UCLP group, and the CP group. Individuals were treated with the identical surgical technique by the same surgeon and had no history of orthodontic/orthopedic treatment. Lateral cephalograms taken 1 month before ABG were analyzed using 29 variables. One-way analysis of variance (ANOVA) testing and bivariate and logistic regression analyses were performed.Results:An increasing tendency for Class III relationships in the order of UCLA, UCLP, and CP was noted (ANB, AB-to-facial plane angle, AB-to-mandibular plane angle; P < .001, respectively). UCLP and CP groups demonstrated more posterior positioning of the maxilla (SNA, A-to-N-perp; P < .001, respectively) and a hyperdivergent pattern (gonial angle, SN-GoMe angle, FMA; P < .001, respectively) compared with the UCLA group. Because no differences in palatal plane angle and SN-to-occlusal plane angle were noted among the three groups, the hyperdivergent pattern in the UCLP and CP groups might be due to an innate growth pattern and eventual adaptation of the mandible to maxillary growth. UCLP and CP groups showed more Class III relationships (ANB: P < .05, P < .001, respectively) and a more hyperdivergent pattern (FMA: P < .05, P < .01, respectively) than the UCLA group.Conclusion:When the degree of cleft involvement increases from the primary palate to the secondary palate, the predominance of the Class III relationship and the hyperdivergent pattern increases also.     

Ethnic differences in craniofacial and upper spine morphology in children with skeletal Class II malocclusion

Objectives:To analyze differences in upper cervical spine and craniofacial morphology, including posterior cranial fossa and growth prediction signs, between Danish and South Korean pre-orthodontic skeletal Class II children and to analyze associations between upper cervical spine morphology and craniofacial characteristics.Materials and Methods:One hundred forty-six skeletal Class II children—93 Danes (54 boys and 39 girls, mean age 12.2 years) and 53 Koreans (27 boys and 26 girls, mean age 10.8 years)—were included. Upper spine morphology, Atlas dimensions, and craniofacial morphology, including posterior cranial fossa and growth prediction signs, were assessed on lateral cephalograms. Differences and associations were analyzed by multiple linear and logistic regression analyses adjusted for age and gender.Results:Significant differences between the ethnic groups were found in the sagittal and vertical craniofacial dimensions (P < .001), mandibular shape (P < .01), dental relationship (P < .01), posterior cranial fossa (P < .05), and growth prediction signs (P < .001). No significant differences were found in upper spine morphology and Atlas dimensions between the groups. Upper spine morphology/dimensions were significantly associated with the cranial base angle (P < .01), sagittal craniofacial dimensions (P < .001), posterior cranial fossa (P < .001), and growth prediction signs (P < .05).Conclusions:Upper spine morphology/dimensions may be valuable as predictive factors in treatment planning for growing Class II children.     

Three-dimensional positional assessment of glenoid fossae and mandibular condyles in patients with Class II subdivision malocclusion

Objectives:To test the null hypotheses that the positions of the glenoid fossae and mandibular condyles are identical on the Class I and Class II sides of patients with Class II subdivision malocclusion.Materials and Methods:Retrospective three-dimensional (3D) assessments of the positions of the glenoid fossae and mandibular condyles were made in patients with Class II malocclusion. Relative to a fiducial reference at the anterior cranial base, distances from the glenoid fossae and condyles were calculated in pretreatment cone beam computed tomographic scans of 82 patients: 41 with Class II and 41 with Class II subdivision malocclusions. The 3D distances from glenoid fossae to sella turcica in the X (right-left), Y (anterior-posterior), Z (inferior-superior) projections were calculated.Results:Patients with Class II malocclusion displayed a symmetric position of the glenoid fossae and condyles with no statistically significant differences between sides (P > .05), whereas patients with Class II subdivision showed asymmetry in the distance between the glenoid fossae and anterior cranial base or sella turcica (P < .05), with distally and laterally positioned glenoid fossae on the Class II side. (P < .05). Male patients had greater distances between glenoid fossae and anterior cranial fossae (P < .05). The condylar position relative to the glenoid fossae did not differ between the two malocclusion groups nor between males and females (P > .05).Conclusions:The null hypotheses were rejected. Patients with Class II subdivision malocclusion displayed asymmetrically positioned right- and left-side glenoid fossae, with a distally and laterally positioned Class II side, although the condyles were symmetrically positioned within the glenoid fossae.     

Tooth-borne vs bone-borne rapid maxillary expanders in late adolescence

Objective:To evaluate the immediate effects of rapid maxillary expansion (RME) on the transverse skeletal and dentoalveolar changes with bone-borne (C-expander) and tooth-borne type expanders using cone-beam computed tomography (CBCT) in late adolescents.Materials and Methods:A sample of 28 female late-adolescent patients was divided into two groups according to the type of expander: bone-borne (C-expander, n  =  15, age  =  18.1 ± 4.4 years) and tooth-borne (hyrax, bands on premolars and molars, n  =  13, age  =  17.4 ± 3.4 years). CBCT scans were taken at 0.2-mm voxel size before treatment (T1) and 3 months after RME (T2). Transverse skeletal and dental expansion, alveolar inclination, tooth axis, vertical height of tooth, and buccal dehiscence were evaluated on maxillary premolars and molars. Paired t-test, independent t-test, one-way analysis of variance, and Scheffé post hoc analysis were performed.Results:The C-expander group produced greater skeletal expansion, except in the region of the first premolar (P < .05 or < .01), which showed slight buccal tipping of the alveolar bone. The Hyrax group had more buccal tipping of the alveolar bone and the tooth axes, except in the region of the second molar (P < .05 or < .01 or < .001). Dental expansion at the apex level was similar in the banded teeth (the first premolar and the first molar). Vertical height changes were apparent on the second premolar in the hyrax group (P < .05 or < .01). Significant buccal dehiscence occurred at the first premolar in the hyrax group (P < .01 or < .001). There were no significant differences between tooth types for any variables in the C-expander group.Conclusions:For patients in late adolescence, bone-borne expanders produced greater orthopedic effects and fewer dentoalveolar side effects compared to the hyrax expanders.     

Evaluating the effects of functional orthodontic treatment on mandibular osseous structure using fractal dimension analysis of dental panoramic radiographs

ObjectiveTo evaluate the effects of functional appliance treatment on mandibular trabecular structure using fractal dimension (FD) analysis of dental panoramic radiographs.Materials and MethodsThis study was conducted using digital panoramic radiographs of 45 patients with Class II malocclusion treated with functional appliances (treatment group, mean age: 11.39 ± 0.97 years; 23 girls, 22 boys) acquired before (T0) and after (T1) treatment and the panoramic radiographs of 45 control subjects who had undergone no orthodontic treatment (control group, mean age: 11.31 ± 0.87 years; 23 girls, 22 boys). FD values in the condylar process, mandibular corpus, and mandibular angle were analyzed from the panoramic radiographs of both groups.ResultsAnalysis of changes in FD between T0 and T1 revealed significant increases in the FD values of the right and left condylar processes and right mandibular corpus in the treatment group (P < .001) and in the right condylar process in the control group (P < .05). Between-group comparisons demonstrated that the treatment group showed greater changes in the condylar process (right, P < .001; left, P < .05) and right mandibular corpus (P < .05) compared to controls. Correlation analysis between the cephalometric and FD changes in the treatment group showed the right condylar process changes were negatively correlated with GoGn/SN angle (P < .05) and positively correlated with Co-Go (P < .05), although these correlations were weak.ConclusionsFD analysis demonstrated significant changes in trabeculation of the condyle and mandibular corpus in the treatment group compared to the control group. Functional appliance treatment may lead to skeletal correction by altering skeletal form and trabeculation of the mandibular bone.     

Pharyngeal airway space,hyoid bone position and head posture after orthognathic surgery in Class III patients

Objective:To determine the effect of orthognathic surgery on pharyngeal airway in Class III patients and to (1) compare the results of different surgical techniques, (2) determine the change at the position of the hyoid bone, and (3) evaluate the craniocervical posture changes related to pharyngeal airway change.Materials and Methods:Forty-eight Class III adult patients were included in the study to assess airway space after orthognathic surgery. Nine patients were treated with maxillary advancement, seven patients were treated with mandibular set back, and 32 patients were treated with bimaxillary surgery. Cephalometric records were taken before treatment, after surgery, and about 1 year after surgery (at the end of the treatment).Results:No differences were determined at the position of hyoid bone and craniocervical posture. Nasopharyngeal area was significantly increased in all groups (P < .05). Oropharyngeal area and SPSS and IPS parameters were significantly decreased after mandibular set back operation (P < .05). In bimaxillary and maxillary advancement groups, PPS parameter was significantly increased (P < .01), and IPS parameter was significantly decreased (P < .05). No differences were detected at oropharyngeal and hypopharyngeal areas in bimaxillary and maxillary advancement groups.Conclusion:Different surgical procedures have different effects on pharyngeal airway space.     

Class II subdivision treatment with the Forsus Fatigue Resistant Device vs intermaxillary elastics

Objective:To compare the effectiveness of comprehensive fixed appliance treatments implemented in combination with Forsus or intermaxillary elastics in Class II subdivision subjects.Materials and Methods:Twenty-eight Class II subdivision patients were allocated to two groups using matched randomization: Forsus group (mean age, 14.19 ± 1.02 years) and elastics group (mean age, 13.75 ± 1.16 years). Patients received fixed appliance therapy in combination with either Forsus or intermaxillary elastics. The study was conducted on lateral cephalograms and digital models acquired before orthodontic treatment and 10–12 weeks after the fixed appliances were removed.Results:The treatment phase comprising the use of Forsus (4.53 ± 0.91 months) was significantly shorter compared with elastics application (6.85 ± 1.08 months). This was also true for comparing duration of overall comprehensive treatment in both groups. Extrusion and palatal tipping of maxillary incisors and clockwise rotation of the occlusal plane were greater in the elastics group (P < .05). The mandibular incisors were proclined in both groups (P < .001), but no significant difference was observed between groups (P > .05). The mandibular incisors showed intrusion in the Forsus group and extrusion in the elastics group; the difference between groups was significant (P < .05). Overbite was decreased in both groups (P < .001) in similar amounts. Improvement in overjet, mandibular midline deviation, and correction of molar relationship on the Class II side were greater in the Forsus group (P < .05).Conclusion:Forsus is more effective for correcting Class II subdivision malocclusion in a shorter treatment period with minimal patient compliance required.     

Assessment of pharyngeal airway volume in adolescent patients affected by bilateral cleft lip and palate using cone beam computed tomography

Objective:To test the null hypothesis that there were no significant differences for pharyngeal airway volumes between the adolescent patients affected by bilateral cleft lip and palate (BCLP) and well-matched controls using cone beam computed tomography.Materials and Methods:The study sample consisted of 16 patients (11 female and 5 male; mean [SD] age 14.1 [2.1] years) affected by BCLP and 16 patients (10 female and 6 male; mean [SD] age 13.4 [2.0] years) as age- and sex-matched control group. Craniofacial measurements and pharyngeal airway dimension, area, and volume measurements of patients in both groups were calculated and statistically examined using Student''s t-test and multiple linear regression analyses.Results:Statistically significant differences were found between the BCLP and control groups for SNB (P < .05), SN-GoGn (P < .05), Co-A (P < .05), PAS (P < .01), minAx (P < .01), and oropharyngeal airway volume (P < .05). The most predictive variables for oropharyngeal airway volume were found as PAS (r  =  .655 and P  =  .000) and minAx (r  =  .787 and P  =  .000).Conclusions:The null hypothesis was rejected. Oropharyngeal (P < .05) and total (P > .05) airway volumes were found to be less in the BCLP group, and thus the treatment choice in these patients should have positive effects on the pharyngeal airway.     

Effect of posterior impaction and setback of the maxilla on retropalatal airway and velopharyngeal dimensions after two-jaw surgery in skeletal Class III patients

Objective:To evaluate the changes in retropalatal airway and velopharyngeal dimensions after posterior impaction (PI) only or PI and setback (PI/SB) of the maxilla in patients with skeletal Class III undergoing two-jaw surgery.Materials and Methods:Subjects consisted of 60 Class III patients treated with two-jaw surgery. They were divided into two groups: group 1 (n  = 30; PI of the maxilla; mean  =  2.6 mm) and group 2 (n = 30; PI/SB of the maxilla; mean  =  2.8 mm and 1.8 mm, respectively). Using three dimensional computed tomography images taken 1month before surgery (T0) and at least 6 months after surgery (T1), retropalatal airway volume, minimum cross-sectional area, and lateral and anteroposterior (AP) dimensions of minimum cross-sectional area, soft palate angle, soft palate length, and pharyngeal depth were measured. A paired t-test and independent t-test were used for statistical analysis.Results:Group 1 showed increase in retropalatal airway volume and minimum cross-sectional area (P < .01 and P < .05, respectively). Group 2 exhibited decrease in retropalatal airway volume, minimum cross-sectional area, and lateral and AP dimensions of minimum cross-sectional area (all P < .01). Although groups 1 and 2 showed an increase in soft palate length (P < .01 and P < .001, respectively), pharyngeal depth significantly increased only in group 1 (P < .01). Groups 1 and 2 were significantly different in retropalatal airway volume, minimum cross-sectional area, and AP dimension (P < .05, P < .001, and P < .05, respectively).Conclusion:Because the direction of surgical movement in the maxilla can determine the changes in the retropalatal airway and velopharyngeal dimensions, it is recommended that clinicians investigate whether patients suffer from sleep-related breathing disorders before performing PI/SB of the maxilla.     

Comparison of arch width,alveolar width and buccolingual inclination of teeth between Class II division 1 malocclusion and Class I occlusion

Objective:To compare the arch width, alveolar width, and buccolingual inclination of maxillary and mandibular posterior teeth between Class II division 1 malocclusion and Class I occlusion.Materials and Methods:Forty-five subjects with Class I occlusion and 45 subjects with Class II division 1 malocclusion were selected to measure the maxillary and mandibular arch width and alveolar width of premolars and first molars with digital caliper. Buccolingual inclination of maxillary and mandibular premolars and first molars were measured with a modified universal bevel protractor.Results:All of the posterior teeth in both groups were lingually tilted. The maxillary premolars and first molars were significantly more lingually tilted (P < .05) in Class II division 1 malocclusion than in Class I occlusion. Mandibular first premolars were significantly less lingually tilted in Class II division 1 malocclusion than in Class I occlusion. No significant difference of buccolingual inclination was found in mandibular second premolars and first molars between the two groups. No significant difference in maxillary and mandibular arch width and alveolar width was found between the two groups.Conclusions:Buccolingual inclination rather than arch width and alveolar width plays an important role in transverse discrepancy of Class II division 1 malocclusion.     

The premature loss of primary first molars: Space loss to molar occlusal relationships and facial patterns

Objective:To investigate space changes with the premature loss of primary first molars and their relationship to permanent molar occlusion and facial forms.Materials and Methods:Two hundred twenty-six participants (ranging in age from 7 years 8 months to 8 years 2 months; 135 female, 91 male) met all inclusion criteria designed to study space loss as a result of the premature loss of the primary first molar. After 9 months, space loss was evaluated in relationship to molar occlusion and facial form. Statistical evaluation was performed with the paired t-test and with a two-way analysis of variance for independent groups.Results:Patients with leptoprosopic facial form and end-on molar occlusions all exhibited a statistically significant difference when compared to controls in terms of space loss (P < .001). The mandibular extraction site for individuals with a mesoprosopic/euryprosopic facial form and end-on molar occlusion displayed space loss as well (P < .05). All patients with a leptoprosopic facial form and Class I molar occlusion displayed space loss in the maxilla (P < .05) and the mandible (P < .001) respectively, that was statistically significant when compared to that of the control. Individuals within the mesoprosopic/euryprosopic group and with Class I molar occlusions showed no significant difference in space loss.Conclusions:The relationship between the first permanent molar occlusion and facial form of the child has an influence on the loss of space at the primary first molar site.     

Three-dimensional analysis of upper airway morphology in skeletal Class III patients with and without mandibular asymmetry

Objective:To compare the three-dimensional (3D) morphology of the upper airway in skeletal Class III patients with and without mandibular asymmetry and to investigate the possible underlying correlations between the morphology of the upper airway and mandibular deviation.Materials and Methods:Cone-beam computed tomography images of 54 subjects with skeletal Class III malocclusion (ANB angle ≤ 0.4°, Wits ≤ −5.5°) were taken and 3D upper airway models were reconstructed using Dolphin 3D software. According to the distance (d) from symphysis menti to the sagittal plane, all subjects were divided into a symmetry group (d ≤ 2 mm) and an asymmetry group (d ≥ 4 mm). Based on the severity of mandibular deviation, the asymmetry group was divided into subgroup I (4 mm ≤d <10 mm) and subgroup II (d ≥ 10 mm). Cross-sectional linear distances, areas, and volumetric variables of the upper airway were measured in the 3D airway model.Results:Width of the inferior limit of the glossopharynx (P3W), cross-sectional area of the anterior limit of the nasal airway (P5S), and height of the glossopharynx (GPH) in the asymmetry group were significantly larger than in the symmetry group. As for subjects with severe mandibular deviation in subgroup II (d ≥ 10 mm), volume of the glossopharynx (GPV), total volume of the pharynx (TPV), length of the inferior limit of the velopharynx (P2L), and ratio of length to width of the inferior limit of the velopharynx (P2L/P2W) showed significantly negative correlations with mandibular deviation (r > 0.7, P < .05).Conclusions:In Class III subjects with severe mandibular asymmetry, the pharyngeal airway showed a tendency toward constriction and presented a more elliptical shape as mandibular deviation became more severe (P < .01).     

Long-term skeletal effects of high-pull headgear followed by fixed appliances for the treatment of Class II malocclusions

Objectives:The long-term skeletal effects of Class II treatment in growing individuals using high-pull facebow headgear and fixed edgewise appliances have not been reported. The purpose of this study was to evaluate the long-term skeletal effects of treatment using high-pull headgear followed by fixed orthodontic appliances compared to an untreated control group.Materials and Methods:Changes in anteroposterior and vertical cephalometric measurements of 42 Class II subjects (n = 21, mean age = 10.7 years) before treatment, after headgear correction to Class I molar relationship, after treatment with fixed appliances, and after long-term retention (mean 4.1 years), were compared to similar changes in a matched control group (n = 21, mean age = 10.9 years) by multivariable linear regression models.Results:Compared to control, the study group displayed significant long-term horizontal restriction of A-point (SNA = −1.925°, P < .0001; FH-NA = −3.042°, P < .0001; linear measurement A-point to Vertical Reference = −3.859 mm, P < .0001) and reduction of the ANB angle (−1.767°, P < .0001), with no effect on mandibular horizontal growth or maxillary and mandibular vertical skeletal changes. A-point horizontal restriction and forward mandibular horizontal growth accompanied the study group correction to Class I molar, and these changes were stable long term.Conclusions:One phase treatment for Class II malocclusion with high-pull headgear followed by fixed orthodontic appliances resulted in correction to Class I molar through restriction of horizontal maxillary growth with continued horizontal mandibular growth and vertical skeletal changes unaffected. The anteroposterior molar correction and skeletal effects of this treatment were stable long term.     

Velopharyngeal changes after maxillary distraction in cleft patients using a rigid external distraction device: A retrospective study

Objective:To evaluate early and late velopharyngeal changes in cleft lip and palate (CLP) patients after use of the Rigid External Distractor (RED) device and to correlate these changes to the amount of maxillary advancement.Materials and Methods:Thirty Class III CLP patients were included in the study. Maxillary advancement was performed using the RED device in combination with titanium miniplates and screws for anchorage. Lateral cephalograms, nasometer, and nasopharyngoscope records were taken before distraction, immediately after distraction, and 1 year after distraction. A paired t-test was used to detect differences at P < .05.Results:SNA angle and A point and ANS to Y axis were significantly increased after maxillary distraction (P  =  .0001). Statistically significant increases in nasopharyngeal and oropharyngeal depths, velar angle, and need ratio were also found (P  =  .0001). Nasalance scores showed a significant increase (P  =  .008 for nasal text and .044 for oral text). A significant positive correlation was observed between the amount of maxillary advancement and the increase in nasopharyngeal depth and hypernasality (P  =  .012 and .026, respectively).Conclusions:Nasopharyngeal function was deteriorated after maxillary advancement in CLP patients. There was a significant positive correlation between the amount of maxillary advancement and the increase in nasopharyngeal depth and hypernasality.     

Upper airway changes after Xbow appliance therapy evaluated with cone beam computed tomography

Objective:To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients.Materials and Methods:The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 ± 1.1 years. CBCT images were obtained at the beginning of the treatment (T0) and after the debonding of the Xbow (T1).Results:Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars.Conclusions:Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.     

Changes in pharyngeal airway dimensions and hyoid bone position after maxillary protraction with different alternate rapid maxillary expansion and construction protocols: A prospective clinical study

Objective:To evaluate the changes in pharyngeal airway dimensions and the position of the hyoid bone after maxillary protraction with different alternate rapid maxillary expansion and construction (Alt-RAMEC) protocols in patients with skeletal class III malocclusion as a result of maxillary retrusion.Material and Methods:The patients with skeletal class III malocclusions were consecutively divided into two groups. Group 1 consisted of 17 patients (11 boys and 6 girls, mean age 11.31 ± 1.71 years) who had the Alt-RAMEC protocol for 5 weeks, and group 2 consisted of 17 patients (10 boys and 7 girls, mean age 11.64 ± 1.24 years) who had the Alt-RAMEC procedure for 9 weeks. In this study, 4 angular and 13 linear measurements were performed to evaluate the skeletal and pharyngeal airway changes that occurred after maxillary protraction.Results:A significant increase in the maxillary growth, inhabitation of mandibular growth, and clockwise rotation of the mandible caused the improvement of the maxillo-mandibular relationship in both groups. Those changes caused a significant increase in the upper pharyngeal airway dimension (P < .01) and affected the vertical position of the hyoid bone in both groups (P < .05 and P < .01, respectively). However, changes that occurred in both groups were found to be similar for all airway variables (P > .05).Conclusion:Upper pharyngeal dimension and vertical position of the hyoid bone were affected by the maxillary protraction with different Alt-RAMEC protocols. There were no statistically significant differences between the groups.     

Evaluation of long-term soft tissue changes after bimaxillary orthognathic surgery in Class III patients

Objective:To assess soft tissues in the short and long term after bimaxillary surgery in Class III patients by comparing the hard tissue changes and results between time periods.Materials and Methods:Twenty-six Class III adult patients treated with bimaxillary surgery were included in the study. Cephalometric records were taken before surgery (T1) and 5 months (T2), 1.4 years (T3), 3 years (T4), and 5 years (T5) after surgery.Results:There was no significant relapse in skeletal parameters. Overjet was significantly reduced between T4-T3 time intervals (P < .01). There were significant increases in Sn-HR, ULA-HR, LLA-HR, B-B^∧ (P < .01), and B^∧-HR (P < .05) between T4-T3 time intervals. There was no significant change in the soft tissue parameters between T5-T4 time intervals.Conclusion:Soft tissue vertical relapse occurs in skeletally stabile Class III bimaxillary surgery patients in the first 3 years after surgery.