Airway imaging with cone-beam computed tomography, magnetic resonance imaging and nasal endoscopy showed anteroposterior (AP) mandibular protrusion predominantly increases the caliber of the airway at the retropalatal area via lateral expansion and displacement of parapharyngeal fat pads 2,6-13 while the tongue and tongue-base muscles shift forward. 2,9,13 The lateral widening from AP movement is attributed to stretching of soft tissue connections KEYWORDS OSA Oral appliance Mandibular advancement Tongue stabilizer KEY POINTSThe concept in oral appliances for obstructive sleep apnea (OSA) management is protrusion of the mandible and/or tongue for structural effects on the upper airway. The upper airway is a muscular tube and its dimensions are enlarged with mandibular and tongue advancement. Protrusion of the mandible and tongue stretches the muscles, thereby reducing upper airway collapsibility with airway shape change and increase in muscle tone. Oral appliances are effective and evidence-based options in managing OSA.

ObjectivesThis systematic review aimed to assess the effects of bicuspid extractions and incisor retraction on airway dimension, hyoid position and breathing of adults and late adolescents.MethodsThe review was conducted according to PRISMA guidelines. Eight databases including PubMed, EMBASE, Web of Science and Scopus were searched to August 2018. Minimum age of participants was 16 years. The intervention was dual‐arch bicuspid extractions with incisor retraction. Outcomes were airway dimension, hyoid position and breathing assessment.ResultsAll nine publications meeting inclusion criteria were from Asia. They were divided into three Asian subregions. All East Asian lateral cephalometric studies reported anteroposterior airway narrowing at the oropharynx and sometimes the hypopharynx. However, the narrowing was small, comparable to measurement errors, and highly variable. Two out of three East Asian computed tomography (CT) studies described reductions in airway dimensions. The single functional breathing study showed increased simulated flow resistance after incisor retraction in East Asians. South Asian studies had mixed findings, with some reporting significant airway narrowing. The single study from West Asia found no significant airway or hyoid changes.ConclusionsAirway response to bicuspid extractions and incisor retraction varied substantially when assessed with cephalometry. CT measurements present larger effect sizes and smaller variations, providing stronger evidence of airway narrowing. Orthodontic extractions for incisor retraction may be more frequently indicated in Asia, and East Asians seem particularly susceptible to airway narrowing and postero‐inferior hyoid movement with incisor retraction. Better designed CT studies are needed for confirmation due to small effect size and large variability.

Objectives The evaluation of orthognathic surgery (OgS) is shifting towards a coherent approach for patient care that balances objective clinician-defined measures with patient-centred outcome assessments, including health-related quality of life (QoL). This aim of this study adds to the pool of literature in East Asian subjects by studying the longitudinal QoL changes in Taiwanese patients with dentofacial deformities (DFD) undergoing OgS, using two standardized questionnaires at three different treatment stages. Materials and Methods This prospective cohort study comprised 113 consecutive Taiwanese OgS patients who underwent surgical-orthodontic treatment between 2015 and 2018. The subjects completed SF-36 and OHIP-14 standardized questionnaires with one additional aesthetics question at one month before OGS (T1), 3 months (T2) and at debond (T3). All responses were screened, and 90 valid questionnaires included for analysis. Additional subgroup comparisons were made between Class II and Class III patients, symmetric and asymmetric patients, surgery-first approach and orthodontics-first approach, presence or absence of genioplasty, genders, and younger and older patients. Results The cohort was comprised largely of skeletal Class III patients (84.4%) and showed significant improvements in OHIP-14 and Aesthetic score from T1 to T3. Pre-surgical orthodontic decompensation leads to a decrease in QoL. Patients who have undergone genioplasty have better generic health QoL than those without genioplasty at T3. Male DFD patients have better generic oral health and aesthetics QoL than female DFD patients. Age does not appear to affect generic health, generic oral health and aesthetics QoL at any time during OgS treatment. Conclusion OgS has positive effects on generic health, generic oral health and aesthetics QoL in DFD patients. The effect of asymmetry on QoL in OgS patients remains an area that requires further research in order to clarify conflicting results in the literature. Future studies should explore the long-term stability of QoL effects. Clinical Relevance: Prospective evaluation with contemporaneous questionnaire surveys at appropriate time points could better reflect the fluctuations of QoL and treatment variables throughout the surgical-orthodontic treatment.

Objectives Two-jaw orthognathic surgery (OGS) is done using either the one-splint technique with free-hand positioning of the maxillomandibular complex or the two-splint technique with intermediate splints to position the maxilla. It is uncertain which technique achieves better outcomes. This study compares frontal soft tissue symmetry and subjective patient QoL between one-splint and two-splint techniques in skeletal Class III asymmetry patients undergoing OGS with three-dimensional surgical planning. Materials and methods This retrospective case-control study comprised 34 one-splint and 46 two-splint OGS patients. Frontal photographs and Orthognathic Quality of Life Questionnaire (OQLQ) were done pre- and post-treatment. Frontal soft tissue symmetry was analysed with the anthropometric Facial Symmetry Index. Measurements were compared with t-tests and chi-squared tests with p-value set at 0.05. Results The groups differed in pre-treatment ANB and OQLQ scores. The two-splint group showed significant improvement in all symmetry measures. The one-splint group showed significant improvement in all symmetry measures except midface deviation, upper contour deviation and the Facial Contour Symmetry Index. Both groups showed significant improvement in OQLQ scores. There were no significant differences in post-treatment symmetry measurements and OQLQ scores between groups. Conclusions Although two-splint technique may better improve contour symmetry, there were no significant differences in frontal soft tissue symmetry and QoL after OGS in skeletal Class III asymmetry with either one-splint or two-splint technique, with both techniques resulting in significant improvement. Clinical relevance One-splint and two-splint surgical techniques produce similar patient-centred outcomes in Class III asymmetry patients.

No abstract