The effects of maxillary expansion on the soft tissue facial profile.

PURPOSE: The aims of this retrospective study were to evaluate the possible changes in soft tissue facial profile induced by orthopedic rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME), and to correlate them with the underlying hard tissue alterations. MATERIALS AND METHODS: 16 patients who received bone borne SARME and 25 patients who were subjected to RME using metal cast splint hyrax appliance were analyzed retrospectively. This research was conducted on lateral cephalometric radiographs taken on 2 occasions: before expansion (T1) and at the beginning of any further orthodontic treatment (T2). Investigated lateral cephalometric parameters consisted of Holdaway soft tissue measurements with some supplementary soft tissue, skeletal and dental assessments. RESULTS: The acquisition of T2 cephalograms which conforms to the initiation of further orthodontic treatment corresponded to 83.25±3.51 days for SARME and 85.68±4.37 days for RME after the expansion was completed. The only significant change in soft tissue profile of the SARME group was a decrease in upper lip thickness (p<0.05), whereas in the RME group, decrease in soft tissue facial profile angle and increase in H angle were found to be statistically significant (p<0.05 for each). For the RME group, the changes in soft tissue facial profile angle and H angle correlated only with the changes in SNB angle (p<0.05). CONCLUSION: While bone-borne SARME did not seem to possess the potential to alter soft tissue profile, tooth-borne RME caused a more convex soft tissue profile related to a reduction in SNB.

Comparison of stepwise vs single-step advancement with the Functional Mandibular Advancer in Class II division 1 treatment.

OBJECTIVE: To compare two groups of subjects at the peak of the pubertal growth period treated with the Functional Mandibular Advancer (FMA; Forestadent, Pforzheim, Germany) appliance using either single-step or stepwise mandibular advancement. MATERIALS AND METHODS: This study was conducted on 34 Class II division 1 malocclusion subjects at or just before the peak phase of pubertal growth as assessed by hand-wrist radiographs. Subjects were assigned to two groups of mandibular advancement, using matched randomization. Both groups were treated with the FMA. While the mandible was advanced to a super Class I molar relation in the single-step advancement group (SSG), patients in the stepwise mandibular advancement group (SWG) had a 4-mm initial bite advancement and subsequent 2-mm advancements at bimonthly intervals. The material consisted of lateral cephalograms taken before treatment and after 10 months of FMA treatment. Data were analyzed by means paired t-tests and an independent t-test. RESULTS: There were statistically significant changes in SNB, Pg horizontal, ANB, Co-Gn, and Co-Go measurements in both groups (P < .001); these changes were greater in the SWG with the exception of Co-Go (P < .05). While significant differences were found in U1-SN, IMPA, L6 horizontal, overjet, and overbite appraisals in each group (P < .001), these changes were comparable (P > .05). CONCLUSION: Because of the higher rates of sagittal mandibular skeletal changes, FMA using stepwise advancement of the mandible might be the appliance of choice for treating Class II division 1 malocclusions.

Upper airway changes following single-step or stepwise advancement using the Functional Mandibular Advancer.

OBJECTIVES: Purpose of the present study was to determine and compare possible changes in the dimensions of the pharyngeal airway, morphology of the soft palate, and position of the tongue and hyoid bone after single-step or stepwise mandibular advancement using the Functional Mandibular Advancer (FMA). PATIENTS AND METHODS: The sample included 51 peak-pubertal Class II subjects. In all, 34 patients were allocated to two groups using matched randomization: a single-step mandibular advancement group (SSG) and a stepwise mandibular advancement group (SWG). Both groups were treated with FMA followed by fixed appliance therapy; the remaining 17 subjects who underwent only fixed appliance therapy constituted the control group (CG). The study was conducted using pre- and posttreatment lateral cephalometric radiographs. Data were analyzed by paired t test, one-way analysis of variance, and Pearson's correlation coefficient. RESULT: In the SWG and SSG, although increases in nasopharyngeal airway dimensions were not significant compared with those in the CG, enlargements in the oropharyngeal airway dimensions at the level of the soft palate tip and behind the tongue, and decreases in soft palate angulation, were significant. Tongue height increased significantly only in the SWG. Compared with the CG, while forward movement of the hyoid was more prominent in SSG and SWG, the change in the vertical movement of the hyoid was not significant. No significant difference between SWG and SSG was observed in pharyngeal airway, soft palate, tongue or hyoid measurements. CONCLUSIONS: The mode of mandibular advancement in FMA treatment did not significantly affect changes in the pharyngeal airway, soft palate, tongue, and hyoid bone.

Treatment of lateral open bite with vertical dentoalveolar distraction osteogenesis.

The aim of this article is to describe the surgical, orthodontic, and periodontal treatment of an adult patient with a lateral open bite, anterior crowding, and gingival recession on the mandibular right lateral incisor. The lateral open bite, which resisted conventional mechanics, was successfully corrected by the combination of dento-osseous osteotomies and vertical alveolar distraction using orthodontic multibracket appliances in conjunction with nickel-titanium archwires and intermaxillary elastics. After the orthodontic treatment, the denuded root surface of the mandibular right lateral incisor was closed using a coronally advanced flap technique with platelet-rich fibrin. The results at the 2-year posttreatment follow-up were satisfactory from both the occlusal and the periodontal standpoints.

Biomechanical evaluation of sagittal maxillary internal distraction osteogenesis in unilateral cleft lip and palate patient and noncleft patients: a three-dimensional finite element analysis.

OBJECTIVE: To compare the pattern and amount of stress and displacement during maxillary sagittal distraction osteogenesis (DO) between a patient with unilateral cleft lip and palate (UCLP) and a noncleft patient. MATERIALS AND METHODS: Three-dimensional finite element models for both skulls were constructed. Displacements of the surface landmarks and stress distributions in the circummaxillary sutures were analyzed after an anterior displacement of 6 mm was loaded to the elements where the inferior plates of the distractor were assumed to be fixed and were below the Le Fort I osteotomy line. RESULTS: In sagittal plane, more forward movement was found on the noncleft side in the UCLP model (-6.401 mm on cleft side and -6.651 mm on noncleft side for the central incisor region). However, similar amounts of forward movement were seen in the control model. In the vertical plane, a clockwise rotation occurred in the UCLP model, whereas a counterclockwise rotation was seen in the control model. The mathematical UCLP model also showed higher stress values on the sutura nasomaxillaris, frontonasalis, and zygomatiomaxillaris on the cleft side than on the normal side. CONCLUSIONS: Not only did the sagittal distraction forces produce advancement forces at the intermaxillary sutures, but more stress was also present on the sutura nasomaxillaris, sutura frontonasalis, and sutura zygomaticomaxillaris on the cleft side than on the noncleft side.

Comparative evaluation of nasopharyngeal airways of unilateral cleft lip and palate patients using three-dimensional and two-dimensional methods.

AIM: Comparison of nasopharyngeal airway dimensions among UCLP patients and the control group. MATERIALS AND METHODS: Computed tomography imaging data and cephalometric films of 20 patients with UCLP and 20 controls were acquired prior to treatment. Three-dimensional (3D) reconstructions of nasal, superior, middle, and inferior pharyngeal airways were carried out from dicom data, and volumes of these compartments were calculated. Nasal width and superior, middle, and inferior nasopharyngeal areas were calculated from cephalometric films. RESULTS: The only statistically significant difference among the cleft and noncleft patients was detected in nasal volume (p < .01). Upper and middle pharyngeal airway areas were found to display significant larger areas in the noncleft group on cephalometric appraisal. Nonsignificantly larger nasal widths were measured in the cleft group. DISCUSSION AND CONCLUSION: Evaluation of the nasopharyngeal airways of cleft and noncleft patients was done, resulting in only the nasal region showing statistically significant difference. Our results showed significantly lower nasal volume measurements of cleft patients when compared with the healthy individuals (p < .01). This inadequacy can be interpreted as an outcome of the deficiency. The controversy among results of cephalometric appraisal and 3D imaging can be associated with superimpositions, density, and contrast inadequacies and obscured landmarks. When 2D data are compared with 3D data, the former can be insufficient and therefore deceiving. Consequently, although the radiation dose of 3D imaging systems is greater, they have the advantage of superior diagnostic outputs.

Comparative assessment of dental arch relationships using Goslon Yardstick in patients with unilateral complete cleft lip and palate using dental casts, two-dimensional photos, and three-dimensional images.

OBJECTIVE: Comparison of the use of two-dimensional (2D) and three-dimensional (3D) images for rating dental arch relationships. MATERIALS AND METHODS: The sample consists of pretreatment dental casts, 2D photographs, and 3D images of 70 patients with unilateral complete cleft lip and palate. Two experienced examiners used the Goslon Yardstick to rate dental arch relationships. The ratings were done three times for all groups. Weighted kappa statistics were used to evaluate intra- and interrater agreement and the agreement between the groups. RESULTS: Intra- and interexaminer agreement were high for all groups (between 0.86 and 0.96), indicating very good reproducibility. The mean Goslon scores ranged between 2.84 and 2.90. CONCLUSION: 2D and 3D imaging of dental casts provides a valid alternative for actual study models for rating dental arch relationships.