Long-term skeletodental stability of mandibular symphyseal distraction osteogenesis: Tooth-borne vs hybrid distraction appliances

Objective:To evaluate and compare the long-term skeletodental stability of mandibular symphyseal distraction osteogenesis (MSDO) achieved with the use of tooth-borne vs. hybrid distraction appliances.Materials and Methods:Posttreatment and follow-up orthodontic records were collected for 33 patients. The 14 patients who underwent distraction with a tooth-borne appliance had a mean follow-up of 5.08 years. The 19 patients who underwent distraction with a hybrid appliance had a mean follow-up of 6.07 years. Records included intraoral photographs, study models, postero-anterior cephalometric radiographs, and lateral cephalometric radiographs. Total changes of 16 measurements were analyzed to compare patients who underwent the tooth-borne vs. the hybrid distraction.Results:Both groups shared several similar and significant (P < .05) changes from posttreatment to follow-up records. Cast analysis showed a decrease in intercanine width and arch length and an increase in irregularity index. The postero-anterior cephalometric radiograph showed an increase in the width of the interincisal apices. The lateral cephalometric radiograph showed a decrease in the MP-L1 angle. The only statistically significant difference between the two appliances was the intercentral incisor contact point.Conclusion:Changes found are consistent with those found in untreated and orthodontically treated individuals over time. The long-term changes in the current patient sample can be determined to be expected and acceptable. MSDO is a viable treatment option with the use of either a hybrid or tooth-borne appliance.     

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.     

Effects of rapid maxillary expansion on nasal mucociliary clearance

Objective:To evaluate the changes in nasal mucociliary clearance in orthodontic patients after rapid maxillary expansion (RME) therapy.Materials and Methods:Forty-two children (25 boys and 17 girls) participated in this study. The RME group consisted of 21 patients (mean age, 13.8 years), who had undergone RME at the initiation of orthodontic treatment. The control group consisted of 21 subjects (mean age, 13.6 years), who were attending the department of orthodontics for active orthodontic treatment. The nasal mucociliary clearance was assessed by the saccharin test. Saccharin transit times (STTs) were measured for each treated subject before expansion (T1), after RME (T2), and after a 3-month retention period (T3). Records were obtained at the same time intervals for each group.Results:The STT decreased significantly in the RME group after expansion and retention (P < .05). A statistically significant difference was found when the STTs of the control and RME groups were compared after expansion and retention (P < .05).Conclusions:The STTs of young orthodontic patients with maxillary narrowness and without any history of nasal or systemic disease were within normal limits. However, RME increased the mucociliary clearance in patients who had maxillary narrowness, having positive effects on nasal physiology and increasing nasal cavity volume.     

Three-dimensional nasal septum and maxillary changes following rapid maxillary expansion in patients with cleft lip and palate:: A case-series analysis

ObjectivesTo determine the three-dimensional changes of the nasal septum (NS), alveolar width, alveolar cleft volume, and maxillary basal bone following rapid maxillary expansion (RME) in consecutive patients with unilateral cleft lip and palate (UCLP).Materials and MethodsA retrospective investigation was conducted based on the analysis of cone-beam computed tomography (CBCT) data of 40 consecutive patients with UCLP (mean age 11.1 ± 2.2 years). Scans were acquired prior to RME (T0) and after removal of the expander (T1) before graft surgery. A three-dimensional analysis of the effects of RME on the nasal septum, alveolar width, alveolar cleft volume, and maxillary basal bone was performed.ResultsNo changes in the NS deviation were observed following RME (P > .05). Significant increases of the alveolar transverse dimension were found in the anterior (14.2%; P < .001) and posterior (7.7%; P < .001) regions as well as in the volume of the alveolar cleft (19.6%; P < .001). No changes in the basal bone dimensions and morphology were observed (P > .05).ConclusionsFollowing RME, no changes were observed in the NS and maxillary basal bones of patients with UCLP despite the significant gain in the anterior and posterior alveolar width and the increase of the alveolar cleft defect. Clinicians should be aware that maxillary changes following RME in patients with UCLP are restricted to the dentoalveolar region.     

Condylar response to functional therapy with Twin-Block as shown by cone-beam computed tomography

Objective:To evaluate the condylar changes through cone-beam computed tomography (CBCT) images in patients treated with Twin-Block functional appliance.Materials and Methods:In this retrospective study, CBCT images of 30 patients who were treated with the Twin-Block appliance were used. Mandible was segmented and pretreatment and posttreatment (T0 and T1) condylar volume was compared. The angle between sella-nasion-Point A (SNA), angle between sella-nasion-Point B (SNB), angle between Point A-nasion-Point B (ANB), midfacial length (Co-A), mandibular length (Co-Gn), and the distances from right condylion to left condylion (Co_R-Co_L) were also measured on three-dimensional images. Differences were analyzed with Wilcoxon signed rank tests, and Mann-Whitney U-tests were used to compare the scores of male and female participants. Significance was set at P < .05.Results:In this study, a decrease in SNA and ANB (P < .05 and P < .01, respectively) and an increase in SNB (P < .01) were found. Additionally, Co_R-Co_L, Co-Gn, and condylar volume increased at both the left and right sides (P < .01). However, increase at Co-A was not statistically significant (P > .05). Comparison of differences by sex was not statistically significant for all measurements (P > .05).Conclusion:Twin-Block appliance increases condylar volume, mandibular length, and intercondylar distance by stimulating growth of condyle in an upward and backward direction.     

Three-dimensional changes of the hyoid bone and airway volumes related to its relationship with horizontal anatomic planes after bimaxillary surgery in skeletal Class III patients

Objective:To evaluate longitudinal changes of the hyoid bone position and pharyngeal airway space after bimaxillary surgery in mandibular prognathism patients.Materials and Methods:Cone-beam computed tomography scans were taken for 25 mandibular prognathism patients before surgery (T0), 2 months after surgery (T1), and 6 months after surgery (T2). The positional displacement of the hyoid bone was assessed using the coordinates at T0, T1, and T2. Additionally, the volume of each subject''s pharyngeal airway was measured.Results:The mean amount of posterior maxilla impaction was 3.76 ± 1.33 mm as the palatal plane rotated 2.04° ± 2.28° in a clockwise direction as a result of bimaxillary surgery. The hyoid bone moved backward (P < .05, P < .001) and downward (P > .05, P < .05) at 2 months and 6 months after surgery, while the total volume of the pharyngeal airway significantly decreased at the same time points (P < .001, P < .001). There was significant relationship between the changes of the hyoid bone position and airway volume at 2 months after surgery (P < .05). The change of the palatal plane angle was positively correlated to the decrease in the total airway volume (P < .001).Conclusions:The null hypothesis was rejected. The hyoid bone moved inferoposteriorly, and the pharyngeal airway volume decreased for up to 6 months after bimaxillary surgery. The decrease in the pharyngeal airway volume was correlated to the changes in the palatal plane inclination and the positional change of the hyoid bone.     

Three-dimensional assessment of the spheno-occipital synchondrosis and clivus after tooth-borne and bone-borne rapid maxillary expansion:: A retrospective CBCT study using voxel-based superimposition

ObjectivesTo assess changes in spheno-occipital synchondrosis after rapid maxillary expansion (RME) performed with conventional tooth-borne (TB) and bone-borne (BB) appliances.Materials and MethodsThis study included 40 subjects with transverse maxillary deficiency who received TB RME or BB RME. Cone-beam computed tomography images (CBCT) were taken before treatment (T0), and after a 6-month retention period (T1). Three-dimensional surface models of the spheno-occipital synchondrosis and basilar part of the occipital bone were generated. The CBCTs taken at T0 and T1 were registered at the anterior cranial fossa via voxel-based superimposition. Quantitative evaluation of Basion displacement was performed with linear measurements and Euclidean distances. The volume of the synchndrosis was also calculated for each time point as well as the Nasion-Sella-Basion angle (N-S-Ba°). All data were statistically analyzed to perform inter-timing and intergroup comparisons.ResultsIn both groups, there was a small increment of the volume of the synchondrosis and of N-S-Ba° (P < .05). Basion showed a posterosuperior pattern of displacement. However, no significant differences (P > .05) were found between the two groups.ConclusionsAlthough TB and BB RME seemed to have some effects on the spheno-occipital synchondrosis, differences were very small and clinically negligible.     

Effects of symmetric and asymmetric rapid maxillary expansion treatments on pharyngeal airway and sinus volume:: A cone-beam computed tomography study

ObjectiveTo evaluate pharyngeal airway and maxillary sinus volumes following symmetric rapid maxillary expansion (RME) and asymmetric rapid maxillary expansion (ARME) treatment using cone-beam computed tomography (CBCT).Materials and MethodsThe study consisted of 60 patients presenting to the orthodontics clinic with an indication that they required symmetric or asymmetric rapid maxillary expansion treatment. Individuals were included if they were aged 12–15 years and had symmetric (RME group; 14 girls, 16 boys) or asymmetric (ARME group; 16 girls, 14 boys) maxillary deficiency. Maxillary sinus volume (mm³) and pharyngeal airway volume (upper, lower, and total; mm³) were evaluated using CBCT records. The parameters were compared before treatment (T1) and after 3 months in retention (T2).ResultsAll measurements at T2 were increased significantly compared with T1 in the RME group (P < .05). In the ARME group, changes in the lower pharyngeal airway and the nonaffected maxillary sinus volumes (non-affected side of maxillary sinus volumes) were not significant; however, the other measurements increased significantly from T1 to T2 (P < .05). Intergroup comparisons revealed that total pharyngeal airway volume and total maxillary sinus volume changes were significantly greater in the RME group.ConclusionsPharyngeal airway and maxillary sinus volumes increased with both RME and ARME treatment. Both were found to be effective for treating transverse maxillary deficiency.     

Comparison of the effects of RME and fan-type RME on nasal airway by using acoustic rhinometry

Objective:To evaluate and compare the nasal airway changes following rapid maxillary expansion (RME) and fan-type RME using acoustic rhinometry (AR).Materials and Methods:The study sample consisted of three groups. The RME group comprised 15 subjects with maxillary transverse discrepancies and posterior crossbites. The fan-type RME group comprised 15 subjects, who had an anteriorly constricted maxilla with a normal intermolar width. The third group included 15 patients who had an ideal occlusion and received no orthodontic treatment and served as the control group. AR was used to measure nasal volume and the minimal cross-sectional area (MCA) before expansion (T1), after expansion (T2), and 6 months after expansion (T3). Each AR recording was performed with and without the use of a decongestant. Two-way analysis of variance was used to determine differences among the groups and three-way analysis of variance was used for the differences between groups. If evidence of statistically significant differences was found, a Bonferroni test was used.Results:The results showed that nasal volume and MCA were significantly increased with RME and fan-type RME immediately after expansion (P < .05). At the end of retention, nasal volume and MCA values of RME showed significant differences with both expansion fan-type RME and control groups (P < .05).Conclusions:RME and fan-type RME had similar effects on the nasal airway immediately after expansion. The increase in nasal volume and MCA was more stable in the RME group than in the fan-type RME group at the end of the retention period.     

Skeletal and dental effects of tooth-borne versus hybrid devices for mandibular symphyseal distraction osteogenesis

Objective: To evaluate and compare, retrospectively, the skeletal and dental effects of mandibular symphyseal distraction osteogenesis (MSDO) achieved through the use of tooth-borne versus hybrid distractors.Materials and Methods:Pretreatment (T1), predistraction (T2), postdistraction (T3), and posttreatment (T4) orthodontic records were collected and analyzed for 47 patients (20 tooth-borne, 27 hybrid). At each time point, records included intraoral photographs, study models, postero-anterior cephalometric radiographs, and lateral cephalometric radiographs. Submental vertex radiographs were taken at T2, T3, and T4. Changes in a total of 18 measurements were analyzed to compare patients undergoing tooth-borne versus hybrid distraction.Results:The cumulative effects of orthodontics and MSDO produced similar gains in measured arch widths, with a decreased irregularity index in both groups (P > .05). However, there were differences in the timing during which the expansion was achieved. The hybrid distractor group gained space during the distraction phase of treatment. The tooth-borne group showed greater gains during pre- and postdistraction orthodontics. Comparisons of intercanine and interbone marker widths demonstrated a more parallel separation of bone during distraction with the hybrid distractor (P < .001). Distraction with the tooth-borne distractor was disproportionate, with greater separation of the canines in alveolar bone than of the bone markers in basal bone. During postdistraction orthodontics, the tooth-borne distractor group showed statistically greater increases in measurements.Conclusion:Both skeletal and dental expansion was achieved with both appliances. Greater skeletal expansion was achieved with a hybrid distractor. Greater dental expansion was achieved with a tooth-borne distractor.     

Efficacy of injectable platelet-rich plasma in reducing alveolar bone resorption following rapid maxillary expansion: A cone-beam computed tomography assessment in a randomized split-mouth controlled trial

Objectives:To evaluate the effectiveness of platelet-rich plasma (PRP) with its growth factors in minimizing the side effects of rapid maxillary expansion (RME) on the periodontal tissue of anchoring teeth using cone-beam computed tomography (CBCT).Materials and Methods:A randomized, split-mouth clinical trial was conducted on 18 patients aged 12–16 years (14 ± 1.65) with a skeletal maxillary constriction who underwent RME using a Hyrax appliance. The sample was randomly divided into two groups: intervention and control sides. PRP was prepared and injected on the buccal aspect of supporting teeth in the intervention group. High-resolution CBCT imaging (H-CBCT) was carried out preoperatively (T0) and after 3 months of retention (T1) to study the buccal bone plate thickness (BBPT) and buccal bone crest level (BBCL) of anchoring teeth. Changes induced by expansion were evaluated using paired sample t-test (P < .05).Results:Results showed that there was no significant difference in BBPT and BBCL between the two groups after RME (P > .05). The prevalence of dehiscence and fenestrations was increased at (T1) in both groups and the percentage was higher in the PRP group.Conclusions:RME induced vertical and horizontal bone loss. PRP did not minimize alveolar defects after RME.     

Mandibular bi-directional distraction osteogenesis: A technique to manage both transverse and sagittal mandibular diameters via a lingual tooth-borne acrylic plate and double-hinge bone anchorage

PurposeMandibular hypoplasia can develop transversely, sagittally, or in both diameters simultaneously. Current techniques achieve either sagittal or transverse expansion with different surgeries. Here, we present a novel method to obtain transverse and sagittal mandibular distraction in one stage.Materials and methodsThe technique consists of a double osteotomy: a dento-alveolar osteotomy comprising four or six anterior teeth and a vertical symphysiotomy underneath. The mandibular basal bone is immediately expanded transversely and fixed to the lower symphysis via a miniplate carrying only one screw on each side that functions as a hinge during active distraction. The plate is connected to the anterior dento-alveolar block with a metal wire ligature. A teeth-anchored lingual distraction system can expand transversely at the alveolar bone level and then sagittally with the anterior dento-alveolar segment wired to the lower plate.ResultsSatisfying and stable results were achieved, confirmed by measurements on serial plaster casts.ConclusionTo the best of our knowledge, this is the first proposal for ortho-surgical correction of both transversal and sagittal mandibular hypoplasia via a bi-directional distraction procedure. A combination of bone-hardware anchorage and dental-anchored distraction systems is suggested.Transmucosal hardware emergence and need for a second surgery to remove bone-borne appliances are avoided.     

Pulp blood flow and sensibility in patients with a history of dental trauma undergoing maxillary expansion:: A prospective study

ObjectivesTo assess changes in pulp blood flow (PBF) and pulp sensibility (PS) in teeth of patients with a history of dental trauma undergoing maxillary expansion.Materials and MethodsTwenty-five patients requiring rapid maxillary expansion (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (CO2 snow). Each patient was tested at T1 (prior to expansion), T2 (2 weeks after rapid expansion), and T3 (3 months after expansion). Relationships between PBF, time interval, and history of trauma were evaluated using linear mixed modelling.ResultsWithin the Trauma group, PBF was significantly lower (P ≤ .05) at T2 and T3 in comparison to T1 and significantly lower (P ≤ .05) at T2 in comparison to T3. In the Non-trauma group, PBF at T2 was significantly lower (P ≤ .05) than PBF at T1 and T3; however, no significant difference (P > .05) in PBF was observed when comparing PBF at T1 and T3. In both groups, PS was maintained in almost all teeth (>90%).ConclusionsRME in healthy teeth causes reduction of PBF before reestablishment of pretreatment values. RME in traumatized teeth causes reduction of PBF without PBF being reestablished to pretreatment levels. Teeth with a history of compromise may have reduced adaptive capacity under insults such as RME, which should be appreciated during the informed consent process.     

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.     

Long-term stability of maxillary protraction therapy in Class III patients with complete unilateral cleft lip and palate

Objectives:This study evaluated the long-term stability of maxillary protraction (MP) in patients with complete unilateral cleft lip and palate (UCLP) and identified factors influencing relapse and long-term outcomes.Materials and Methods:Twenty-three adolescents with UCLP who underwent MP therapy were recalled when craniofacial growth was close to completion. Subjects exhibiting reverse/positive overjets were assigned to unstable/stable groups. Lateral cephalometric measurements were made before treatment (T0), after active treatment (T1), and at the end of the growth spurt (T2).Results:About 63% of the subjects exhibited positive overjets during follow-up. The unstable group demonstrated higher B–x and Co–Gn distances than the stable group (both P < .05) at T0. More short-term (T0–T1) sagittal advancement of point A (A–y) was evident in the unstable group than in the stable group (P < .05), but no long-term difference was apparent between the two groups (P = .481). During the posttreatment period (T1–T2), the SNA angle and maxillary incisor protrusion (U1–SN angle) were considerably lower in the unstable group than in the stable group (both P < .05). Overall, the unstable group exhibited a lower increase in the vertical extent of point A (A–x) than the stable group from T0 to T2 (P < .05).Conclusions:In the long term, MP affords favorable maxillary advancement in patients with UCLP. A mandibular excess at T0 and vertical maxillary hypoplasia may contribute to the long-term relapse of a reverse overjet.     

An alternative treatment approach for patients with resistant otitis media with effusion and dysfunctional Eustachian tube:: A pilot study with rapid maxillary expansion

ObjectivesTo determine whether dysfunctional Eustachian tubes of children with resistant otitis media with effusion (OME), ventilation tube placement indication, and maxillary constriction will recover after rapid maxillary expansion (RME).Materials and MethodsThe RME group consisted of 15 children (mean age: 10.07 years) with maxillary constriction, Eustachian tube dysfunction (ETD), and resistant OME. The control group consisted of 11 healthy children (mean age: 8.34 years) with no orthodontic and/or rhinologic problems. Recovery of Eustachian tube dysfunction was evaluated by Williams'' test at three timepoints: before RME/at baseline (T0); after RME (T1); and after an observation period of 10 months (T2). The control group was matched to all these periods, except T1.ResultsIn the control group, functioning Eustachian tubes were observed in all ears at baseline (T0), and tubes showed no worsening and no change during the observation period (T2) (P > .05). In the RME group, functioning Eustachian tubes were observed in eight of 30 ears and ETD was observed in the remaining 22 ears at baseline (T0). The RME group showed significant improvements in tube functions after RME and the observation period (P < .05). Fifteen of 22 dysfunctional ears recovered (68.2%) and started to exhibit normal Eustachian tube function after RME (T1) and the observation period (T2).ConclusionsThe findings suggest that ears having poorly functioning Eustachian tubes are restored and recovered after RME in most of children with maxillary constriction and resistant OME. Thus, RME should be preferred as a first therapy alternative for children with maxillary constriction and serous otitis media.     

Three-dimensional analysis of molar compensation in patients with facial asymmetry and mandibular prognathism

Objective:To evaluate the characteristic transverse dental compensations in patients with facial asymmetry and mandibular prognathism and to compare features of dental compensations between two types of mandibular asymmetry using 3-dimensional (3D) cone-beam computed tomography (CBCT).Materials and Methods:Seventy-eight adult patients with skeletal Class I (control group; n  =  33; 19 men and 14 women) or skeletal Class III with facial asymmetry (experimental group; n  =  45; 23 men and 22 women) were included. The experimental group was subdivided into two groups according to the type of mandibular asymmetry: translation type (T-type; n  =  20) and roll type (R-type; n  =  19). CBCT images were acquired before orthodontic treatment and 3D analyses were performed.Results:The transverse dental distance was significantly different between the two groups only at the palatal root apex of the maxillary first molar (P < .05). In the experimental group, the first molar axes were compensated significantly on both arches except the maxillary nondeviated side. The vertical molar heights were different between the two groups only on the maxillary arch (P < .001). The R-type showed greater mandibular ramal length difference and menton deviation than the T-type (P < .001). In the R-type, transverse compensation of the maxillary first molars was more obvious than with the T-type, which resulted in canting in the maxillary occlusal plane.Conclusions:Mandibular asymmetry with prognathism showed a characteristic transverse dental compensation pattern. The mandibular asymmetry type influenced the amount and direction of molar compensation on the maxillary arch.     

Effects of rapid maxillary expansion on upper airway volume: A three-dimensional cone-beam computed tomography study

Objective:To compare changes in pharyngeal airway volume and minimal cross-sectional area (MCA) between patients undergoing rapid maxillary expansion (RME) and a matched control group and to identify markers for predicting airway changes using cone-beam computed tomography (CBCT).Materials and Methods:Pre- and posttreatment CBCT scans were selected of children who had RME (14 girls and 12 boys; mean age, 12.4 years) along with scans of a control group (matched for chronological age, skeletal age, gender, mandibular inclination) who underwent orthodontic treatment for minor malocclusions without RME. Changes in airway volume and MCA were evaluated using a standardized, previously validated method and analyzed by a mixed-effects linear regression model.Results:Upper airway volume and MCA increased significantly over time for both the RME and matched control groups (P < .01 and P = .05, respectively). Although the RME group showed a greater increase when compared with the matched controls, this difference was not statistically significant. A reduced skeletal age before treatment was a significant marker for a positive effect on the upper airway volume and MCA changes (P < .01).Conclusions:Tooth-borne RME is not associated with a significant change in upper airway volume or MCA in children when compared with controls. The younger the skeletal age before treatment, the more positive the effect on the upper airway changes. The results may prove valuable, especially in RME of young children.     

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.     

Relationship between voice function and skeletal effects of rapid maxillary expansion

Objective:To evaluate the effects of rapid maxillary expansion (RME) on the vocal quality, maxillary central incisors, midpalatal suture, and nasal cavity in patients with maxillary crossbite.Materials and Methods:Coronal CT scans of 30 subjects (14 boys, 16 girls; mean age, 12.01 ± 0.75) were taken before RME (T0), and at the end of the expansion phase (T1). Voice samples of all patients were recorded with a high-quality condenser microphone (RODE NT2-A) on a desktop computer at T0 and T1. Statistical analyses were performed using a paired-sample t-test. The degree of association between the changes in the voice parameters and nasal width was assessed with Pearson''s correlation.Results:RME treatment produced a significant increase in the transverse dimensions of the midpalatal suture and nasal cavity between T0 and T1 (P < .05). The maximum F0 and jitter (%) results were shown to decrease statistically significantly from T0 to T1 (P < .001 and P = .042, respectively). Between T0 and T1, shimmer (%) and shimmer (dB) exhibited statistically significant increases (P = .037 and P = .019, respectively).Conclusions:After RME therapy, voice quality differences were found to be associated with increases in nasal width.