Upper airway changes in Class III patients using miniscrew-anchored maxillary protraction with hybrid and hyrax expanders: a randomized controlled trial.

OBJECTIVES: The aim of this study was to compare the upper airway space changes after miniscrew-anchored maxillary protraction with hybrid (HH) and conventional hyrax (CH) expanders. MATERIAL AND METHODS: The sample comprised Class III malocclusion growing patients that were randomized into two groups of miniscrew-anchored maxillary protraction. The group HH was treated with a hybrid hyrax appliance in the maxilla and two miniscrews distally to the canines in the mandible. Class III elastics were used from the maxillary first molar to the mandibular miniscrews until anterior crossbite correction. The group CH was treated with a similar protocol except for the conventional hyrax expander in the maxilla. Cone-beam computed tomography was obtained before (T1) and after 12 months of therapy (T2). The shape and size of upper airway were assessed. Intergroup comparisons were performed using Mann-Whitney U test (p < 0.05). RESULTS: The group HH was composed of 20 patients (8 female, 12 male) with a mean age of 10.76 years. The group CH was composed of 15 patients (6 female, 9 male) with a mean age of 11.52 years. Anteroposterior and transverse increases of the upper airway were found for both groups. The oropharynx and the most constricted area increased similarly in both groups. CONCLUSIONS: No differences in upper airway changes were observed using protraction anchored on hybrid or conventional hyrax expanders. CLINICAL RELEVANCE: Maxillary protraction anchored on hybrid or conventional hyrax expanders may benefit patients with breathing disorders due to the increase of the upper airway volume and most constricted area. Registration: ClinicalTrials.gov (NCT03712007).

A 3D mirroring and colormap asymmetry study of Class II subdivision patients.

INTRODUCTION: Patients with Class II subdivision malocclusion present skeletal and dental asymmetries. The purpose of this study is to assess those asymmetries by 3D mirroring and colormap quantification. METHODS: This study analyzed 50 initial CBCTs divided into two groups: Class I (control group) and Class II subdivision (study group) malocclusion patients. CBCTs were oriented and full skull was segmented generating a 3D model. The right side of the 3D models was mirrored, using a midsagittal plane as reference, resulting in a perfectly symmetric skull based on two right sides. Original and mirrored models were superimposed on the unchanged right half, and differences were quantified using a colormap. Eight regions of interest were assessed: gonion, mandibular front, maxillary front, zygomatic process, maxillary and mandibular canine and molar areas. RESULTS: Statistically significant differences using the Mann-Whitney test were found in six of the eight evaluated areas when comparing the control to the study group. The maxillary skeletal areas did not show any difference between the groups. CONCLUSIONS: Patients with Class II subdivision malocclusion show true skeletal and dental asymmetries when comparing right and left sides. The maxilla showed no significant skeletal asymmetry, but the maxillary teeth were positioned more mesially on the Class II side. The maxillary canine on the Class II side was also more bucally positioned. The mandible showed significant asymmetries with both skeletal and dental areas in the Class II side more distally and bucally positioned.

Orthopedic outcomes of hybrid and conventional Hyrax expanders.

OBJECTIVES: To compare the effects of a hybrid miniscrew-supported expander versus a conventional Hyrax (CH) expander in growing patients. MATERIALS AND METHODS: Forty patients were randomized into two groups: a hybrid Hyrax (HH) expander group using a Hyrax expander with two miniscrews and a CH expander group. The final sample had 18 subjects (8 female, 10 male; initial age of 10.8 years) in the HH group and 14 subjects (6 female, 8 male; initial age of 11.4 years) in the CH group. Cone-beam computed tomography examinations and digital dental models were obtained before expansion and 11 months postexpansion. The primary outcomes included the orthopedic transverse effects of expansion. Intergroup comparison was performed using analysis of covariance (P < .05). RESULTS: Significantly greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width were found for the HH group. No intergroup differences were observed for dental arch width or shape changes. CONCLUSIONS: The HH group showed greater increases in the nasal cavity width, maxillary width, and buccal alveolar crest width. No differences were observed for intermolar, interpremolar, or intercanine widths; arch length; or arch perimeter. Arch size and shape showed similar changes in both groups.

Dental arch changes comparison between expander with differential opening and fan-type expander: a randomized controlled trial.

OBJECTIVES: To compare posterior crossbite correction frequency and dentoalveolar changes of the expander with differential opening (EDO) and the fan-type expander (FE). TRIAL DESIGN: Two-arm parallel randomized controlled trial. METHODS: Forty-eight patients from 7 to 11 years of age were allocated into two groups. Twenty-four patients were treated with the EDO and 24 patients were treated with the FE. Block randomization was performed. The study was single blind. Digital dental models were acquired before treatment and 6 months after rapid maxillary expansion. The primary outcomes were crossbite correction rate and maxillary arch width changes. Secondary outcomes were interincisal diastema, arch perimeter, length, size and shape, and mandibular dental arch changes. RESULTS: The final sample comprised 24 patients (13 female and 11 male; mean initial age of 7.62 years) in the EDO group and 24 patients (14 female and 10 male; mean initial age of 7.83 years) in the FE group. The crossbites were corrected in 100 per cent of subjects from EDO group and in 75 per cent of patients in FE group. EDO showed greater increases in maxillary intermolar region (P < 0.001), while the FE demonstrated greater increases in the intercanine distance (P = 0.008). Increase in mandibular inter-first permanent molar distance was slightly greater in the EDO group (mean difference of 0.8 mm). Changes in arch length and perimeter were similar in both groups. Both expanders changed the maxillary arch shape. The post-treatment arch shape was larger in the anterior region for FE and in the posterior region in the EDO group. HARMS: Discomfort during activation was reported by 54 per cent of the participants. A temporary change in the nasal bridge was reported by one patient from FE group. CONCLUSIONS: Maxillary arch width and shape changes were distinct between the EDO and the FE. Greater transversal increases of the anterior and posterior regions were observed for the FE and the EDO, respectively. A slightly greater mandibular spontaneous expansion was observed for the EDO only at the molar region. TRIAL REGISTRATION: NCT03705871.

Bone-anchored maxillary protraction long-term outcomes in UCLP.

This case report presents a 12-year-old boy with unilateral complete cleft lip and palate and severe maxillary retrusion treated with bone-anchored maxillary protraction (BAMP) therapy followed by fixed appliances. The follow-up period extended until the end of growth. Initially, the patient demonstrated a Goslon 4 interarch relationship with an overjet of -3.5 mm and a Wits appraisal of -7.9 mm. Six months after the secondary alveolar bone graft, Bollard miniplates were fixed bilaterally at the infrazygomatic region in the maxilla and between the canines and lateral incisors in the mandible. Class III elastics were used bilaterally full time for 12 months. After treatment, the overjet increased 5.9 mm. Significant maxillary advancement (SNA +3.2°) and skeletal convexity improvement (NA-APo +12.4°) were observed. Retrusion of the anteroposterior position of the mandible was observed (SNB -2.1°). Comprehensive orthodontic treatment was performed after BAMP therapy with nighttime bone-anchored Class III elastics as active retention until the end of growth. Occlusion and facial esthetics were satisfactory at the end of orthodontic treatment and growth. Le Fort I surgery for maxillary advancement was not required. BAMP therapy demonstrated an adequate orthopedic outcome, preventing the need for orthognathic surgery in unilateral complete cleft lip and palate.

Dental arch size and shape after maxillary expansion in bilateral complete cleft palate: A comparison of three expander designs.

OBJECTIVE: The objective of this study was to compare the effects on upper dental arch size and shape after maxillary expansion with Hyrax, Quad-helix, and a differential opening expander in bilateral cleft lip and palate (BCLP) patients. MATERIALS AND METHODS: Seventy-five BCLP patients were divided into three groups: Hyrax (H), Quad-helix (QH), and Expander with differential opening (EDO). Digital models were obtained before (T1) and after 6 months (T2) of maxillary expansion. Twelve landmarks were placed by one investigator on T1 and T2 dental models of each group, and x,y coordinates for each landmark were collected. For dental arch size analysis, centroid size of each dental arch at T1 and T2 was calculated from raw coordinates and was used as the measure of size. Procrustes Analysis was performed for dental arch shape analysis. Analysis of variance was used to compare the groups for size and shape differences (P < .05). RESULTS: There were no significant dental arch size differences among the expanders at T1 or T2. Differences in arch shape were found between all groups at T2. Intragroup arch shape showed a significant variation for the QH and EDO groups. while it remained stable in the H group. CONCLUSIONS: Both the QH and the EDO create dental arch shape changes with greater intercanine than intermolar increase. The H does not change the dental arch shape.