One-splint versus two-splint technique in orthognathic surgery for class III asymmetry: comparison of patient-centred outcomes.

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.

Oral Appliances in the Management of Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is a multifactorial condition, and an interdisciplinary approach to diagnosis forms the basis for effective treatment planning. Craniofacial structure and attached soft tissues and muscles play a central role in OSA. Evidence-based studies demonstrate the effectiveness of oral appliances for mandibular advancement and tongue stabilization in managing OSA, and current clinical standards of practice recommend the use of oral appliances to treat OSA when patients cannot tolerate continuous positive airway pressure (CPAP). Although effective, oral appliances are less predictable in managing OSA compared with CPAP therapy. Measures can be taken to improve predictability of oral appliance treatment.

Effects of bicuspid extractions and incisor retraction on upper airway of Asian adults and late adolescents: A systematic review.

OBJECTIVES: This 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. METHODS: The 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. RESULTS: All 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. CONCLUSIONS: Airway 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.

Oral Appliances in the Management of Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is a multifactorial condition, and an interdisciplinary approach to diagnosis forms the basis for effective treatment planning. Craniofacial structure and attached soft tissues and muscles play a central role in OSA. Evidence-based studies demonstrate the effectiveness of oral appliances for mandibular advancement and tongue stabilization in managing OSA, and current clinical standards of practice recommend the use of oral appliances to treat OSA when patients cannot tolerate continuous positive airway pressure (CPAP). Although effective, oral appliances are less predictable in managing OSA compared with CPAP therapy. Measures can be taken to improve predictability of oral appliance treatment.