Bio


Dr. Audrey Yoon is a dual trained orthodontist and pediatric dentist who specializes in sleep medicine and esthetics. She practices the full scope of non-surgical and surgical orthodontics from pediatric to geriatric population for airway management including growth modification, pediatric palatal expansion, customized Miniscrew-Assisted Rapid Palatal Expansion (MARPE), Distraction Osteogenesis Maxillary Expansion (DOME), Orthodontic treatment for Maxillomandibular Advancement ( MMA ), clear aligner therapy and oral appliances for sleep apnea.
She completed her orthodontic and pediatric dentistry residencies at the University of California Los Angeles (UCLA). She also earned her Doctor of Dental Surgery and Master of Science degree, completing extensive research in Obstructive Sleep Apnea (OSA) at UCLA. She is an adjunct assistant professor of Stanford Sleep Medicine Center at Stanford University, an honorary assistant professor of Orthodontics at the University of Hong Kong, an adjunct assistant professor in Orthodontics at University of Pacific and a clinical associate faculty at Tufts University School of Dental Medicine. She is also a co-director of Pediatric Dental Sleep Mini-residency program at Tufts University.
She has introduced on a pioneering technique, performing maxillary distraction osteogenesis for the treatment of OSA and has co-authored chapters on this subject in several leading textbooks. She has created an interdisciplinary rotation program between Stanford Sleep Surgery and the University of Pacific Orthodontic Residency Program and is a co-founder of pediatric dental sleep medicine residency at Tufts University.
Currently her active areas of research include craniofacial growth modification, customized distractor designs, surgery-first approach of maxillomandibular advancement surgery technique, and the genomic study to identify genetic anatomical factors relating to OSA.

Clinical Focus


  • Orthodontics
  • Oral appliance for snoring and sleep apnea
  • Full scope of dental sleep medicine
  • Growth modification from infant to adolescent
  • Rapid Palatal Expansion ( RPE), Miniscrew-Assisted Rapid Palatal Expansion ( MARPE), Distraction Osteogenesis Maxillary Expansion ( DOME)
  • Surgical Orthodontics for Sleep Apnea
  • Surgical set up for Maxillomandibular Advancement ( MMA )

Boards, Advisory Committees, Professional Organizations


  • Diplomate, The American Board of Orthodontics (2019 - Present)
  • Diplomate, The American Board of Dental Sleep Medicine (2019 - Present)
  • Co-Program Director, Pediatric Dental Sleep Medicine Mini-Residency, Tufts University (2018 - Present)

Professional Education


  • Board Certification, The American Board of Dental Sleep Medcine
  • Board Certification, The American Board of Orthodontics
  • Residency: UCLA Orthodontics Residency (2008) CA
  • Residency, UCLA Pediatric Dentistry Residency (2008)
  • MS, UCLA Oral Biology
  • Doctor of Dental Surgery, UCLA School of Dentistry (2004)
  • Doctor of Dental Surgery, Seoul National Universtiy (2000)

All Publications


  • Impact of rapid palatal expansion on the size of adenoids and tonsils in children. Sleep medicine Yoon, A., Abdelwahab, M., Bockow, R., Vakili, A., Lovell, K., Chang, I., Ganguly, R., Liu, S. Y., Kushida, C., Hong, C. 2022; 92: 96-102

    Abstract

    Adenoid and tonsillar hypertrophy in children often leads to adverse respiratory symptoms and obstructive sleep apnea (OSA). Current clinical guidelines from the American Academy of Pediatrics and American Academy of Otolaryngology-Head and Neck Surgery recommend tonsillectomy as the first line of pediatric OSA treatment for children with tonsillar hypertrophy. Rapid palatal expansion (RPE) performed by orthodontists improves obstructive sleep apnea in children by reducing nasal airway resistance, increasing nasal volume, raising tongue posture, and enlarging pharyngeal airway. However, the role of RPE in alleviating adenoid and tonsillar hypertrophy remains elusive. In this study, we aim to evaluate the changes in adenoid and palatine tonsil sizes following RPE using 3D volumetric analysis of cone beam computational tomography (CBCT) imaging.In this retrospective cohort study, a total of 60 pediatric patients (mean age: 8.00, range: 5-15, 32 females and 28 males) who had tonsillar hypertrophy (size 3 and 4) were included and divided into the control group (n = 20) and expansion group (n = 40). The control group did not undergo any treatment. The expansion group underwent RPE using a conventional Hyrax expander, activated 0.25 mm per day for 4-6 weeks. Final CBCT scans (T2) were performed 13.8 ± 6.5 months after the initial scan (T1). Pediatric sleep questionnaire (PSQ) and BMI were obtained at each timepoint. Volumetric analysis of adenoid and palatine tonsils was performed using a combination of bony and soft tissue landmarks in CBCT scans through Anatomage Invivo 6 imaging software. Paired t-tests were used to evaluate the difference between the initial and final adenoid and tonsil volumes. p values less than 0.05 were considered statistically significant.Compared to the control group, the expansion group experienced a statistically significant decrease in both adenoid and tonsil volume. There was non-statistically significant increase in volume from T1 to T2 for the control group. For the expansion group, 90.0% and 97.5% of patients experienced significant reduction in adenoid and tonsil volume, respectively. The average volume decrease of adenoids was 16.8% while that of tonsils was 38.5%. The patients had up to 51.6% and 75.4% reduction in adenoid and tonsil size, respectively, following RPE orthodontic treatment. Pearson correlation ranged from 0.88 to 0.99 for each measurement, representing excellent internal consistency. There was a significant reduction in the PSQ scores from 5.81 ± 3.31 to 3.75 ± 2.38 in expansion group (p < 0.001).Our results demonstrated that RPE significantly reduced the size of both adenoid and palatine tonsils and revealed another long-term benefit of RPE treatment. To our knowledge, this is the first study to quantify the changes of adenoids and tonsils following RPE. RPE treatment can be considered as a valid and effective treatment option for pediatric OSA population with narrow high arch palate and adenotonsillar hypertrophy.

    View details for DOI 10.1016/j.sleep.2022.02.011

    View details for PubMedID 35390750

  • A Minimally Invasive Nasal Endoscopic Approach to Distraction Osteogenesis Maxillary Expansion to Restore Nasal Breathing for Adults with Narrow Maxilla. Facial plastic surgery & aesthetic medicine Liu, S. Y., Ibrahim, B., Abdelwahab, M., Chou, C., Capasso, R., Yoon, A. 2022

    Abstract

    Background: Patients with narrow high-arch palate present with limited response to standard septal, turbinate, and valve procedures for nasal obstruction. Objective: To measure the effectiveness of minimally invasive nasal endoscopic (MINE) Lefort I osteotomy among subjects with narrow high-arched palate in managing nasal obstruction. Methods: Prospective cohort study was performed where subjects with narrow high-arched palate underwent MINE distraction osteogenesis maxillary expansion (DOME) from August 2019 to January 2021. Nasal obstruction symptom evaluation (NOSE) score, mean time to opioid cessation, and mean duration of cranial nerve V2 hypoesthesia were evaluated. Results: Among 12 subjects, the. mean NOSE score decreased from 58.89 to 15.83 (p=0.004). There were no complaints of lip mobility or deformity. Conclusion: MINI-DOME can reduce nasal obstruction in a certain phenotype of patients and further improve patient-centric outcomes by limiting the approach to the Lefort I osteotomy to an endoscopic nasal approach.

    View details for DOI 10.1089/fpsam.2021.0154

    View details for PubMedID 35179990

  • Determinants of Sleep-Disordered Breathing During the Mixed Dentition: Development of a Functional Airway Evaluation Screening Tool (FAIREST-6) PEDIATRIC DENTISTRY Oh, J. S., Zaghi, S., Peterson, C., Law, C. S., Silva, D., Yoon, A. J. 2021; 43 (4): 262-+
  • Assessment of posterior tongue mobility using lingual-palatal suction: Progress towards a functional definition of ankyloglossia JOURNAL OF ORAL REHABILITATION Zaghi, S., Shamtoob, S., Peterson, C., Christianson, L., Valcu-Pinkerton, S., Peeran, Z., Fung, B., Ng, D., Jagomagi, T., Archambault, N., O'Connor, B., Winslow, K., Lano, M., Murdock, J., Morrissey, L., Yoon, A. 2021; 48 (6): 692-700

    Abstract

    A functional definition of ankyloglossia has been based on assessment of tongue mobility using the tongue range of motion ratio (TRMR) with the tongue tip extended towards the incisive papilla (TIP). Whereas this measurement has been helpful in assessing for variations in the mobility of the anterior one-third of the tongue (tongue tip and apex), it may be insufficient to adequately assess the mobility of the posterior two-thirds body of the tongue. A commonly used modification is to assess TRMR while the tongue is held in suction against the roof of the mouth in lingual-palatal suction (LPS).This study aims to explore the utility and normative values of TRMR-LPS as an adjunct to functional assessment of tongue mobility using TRMR-TIP.Cross-sectional cohort study of 611 subjects (ages: 3-83 years) from the general population.Measurements of tongue mobility using TRMR were performed with TIP and LPS functional movements. Objective TRMR measurements were compared with subjective self-assessment of resting tongue position, ease or difficulty elevating the tongue tip to the palate, and ease or difficulty elevating the tongue body to the palate.There was a statistically significant association between the objective measures of TRMR-TIP and TRMR-LPS and subjective reports of tongue mobility. LPS measurements were much more highly correlated with differences in elevating the posterior body of the tongue as compared to TIP measurements (R2 0.31 vs 0.05, P < .0001).This study validates the TRMR-LPS as a useful functional metric for assessment of posterior tongue mobility.

    View details for DOI 10.1111/joor.13144

    View details for Web of Science ID 000608028800001

    View details for PubMedID 33386612

  • Determinants of probable sleep bruxism in a pediatric mixed dentition population: a multivariate analysis of mouth vs. nasal breathing, tongue mobility, and tonsil size SLEEP MEDICINE Oh, J. S., Zaghi, S., Ghodousi, N., Peterson, C., Silva, D., Lavigne, G. J., Yoon, A. J. 2021; 77: 7-13

    Abstract

    This study aims to identify structural and functional craniofacial characteristics that correlate with higher incidence of 'probable' sleep bruxism in children.From March 2018 until March 2019, a cross-sectional clinical study was performed with ninety-six healthy children ages 6-12 years who presented for routine dental examination at the UCLA pediatric dental clinic. Variables of interest included: (1) assessment of probable bruxism based on parental awareness on the frequency of tooth grinding during sleep and clinical signs of bruxism based on tooth wear; (2) parental reports of mouth breathing while awake and asleep, snoring during sleep, difficulty breathing and/or gasping for air during sleep; (3) parental reports of psychosocial distress; (4) assessment of tonsil hypertrophy, tongue mobility, and nasal obstruction. Three pediatric dental residents were calibrated to perform the clinical data collection. All dental residents were graduated dentists with licensure and at least one year of experience examining children. The methodology to take the specific measurements administered in the manuscript were calibrated between the data-collectors under the supervision of a board-certified pediatric dentist and orthodontist (AY).The mean age of individuals was 8.9 (SD = 1.9) years with a gender distribution of 46 males and 50 females. There were 23 out of the 96 (24%) individuals who met the diagnostic criteria for probable sleep bruxism (PSB). Sleep Disturbance Scale for Children (SDSC) scores were significantly elevated among children positive for PSB, indicating that they are at higher risk for sleep disturbances (PSB-positive: 45.1 ± 13.0, PSB-negative: 34.8 ± 5.5; p < 0.0001). Impaired nasal breathing, parental reports of mouth breathing when awake or asleep, restricted tongue mobility, and tonsillar hypertrophy were found to be significant risk factors for PSB. Exploratory analysis further suggests a synergistic effect between tonsil hypertrophy, restricted tongue mobility, and nasal obstruction. The incidence of probable sleep bruxism among individuals without any of the exam findings of tonsillar hypertrophy, restricted tongue mobility, and nasal obstruction was 5/58 (8.6%), whereas the incidence of PSB among individuals with all three exam findings was 10/11 (90.9%), p < 0.0001. Among the 23 individuals with PSB, however, there were n = 5 (21.7%) who did not have any of the three exam findings, suggesting an additional role of psychosocial distress, postural maladaptation, malocclusion, or other factors in the etiology of sleep bruxism.This study shows that tonsil hypertrophy, restricted tongue mobility, and nasal obstruction may have a synergistic association on the presentation of PSB. Dentists should evaluate for tonsillar hypertrophy, restricted tongue mobility, and nasal obstruction in the evaluation of PSB, as these exam findings are highly prevalent in the majority of cases.

    View details for DOI 10.1016/j.sleep.2020.11.007

    View details for Web of Science ID 000618554500002

    View details for PubMedID 33291022

  • Impact of rapid palatal expansion on the internal nasal valve and obstructive nasal symptoms in children SLEEP AND BREATHING Yoon, A., Abdelwahab, M., Liu, S., Oh, J., Suh, H., Trieu, M., Kang, K., Silva, D. 2020

    Abstract

    The aim of this study is to evaluate the impact of rapid palatal expansion (RPE) on the nasal airway subjectively by utilizing patient-reported outcome measures (PROM) and objectively by evaluating validated internal nasal valve (INV) measurements obtained from cone beam computed tomography (CBCT) in pediatrics.In this retrospective cohort study, subjects who underwent RPE from March to December 2018 with cone beam CT and Nasal Obstruction Symptom Evaluation (NOSE) scores were included. Exclusion criteria included craniofacial deformity, allergies, asthma, recent nasal trauma, or surgery. INV measurements (angle and cross-sectional area), diastema, midpalatal suture opening, and NOSE scores were evaluated.Fifty-one subjects met the inclusion criteria with a mean age of 10.1 ± 2.6. Pre-expansion mean NOSE score was 32.55 (moderate) while post-expansion was 13.92 (mild). Mean NOSE score improved significantly by an average of 18.63 following post-expansion (P < 0.0001). The patients' right and left INV angles increased significantly by a mean of 2.42° and 2.65° respectively (P < 0.0001). Right and left INV cross-sectional areas increased significantly by an average of 14.35 mm2 (P < 0.0001) and 14.17 mm2 (P < 0.0001) respectively. An average expansion of the diastema and the suture was 1.60 mm and 3.05 mm respectively (P < 0.0001), with an average of 6.29 mm of expansion. We found the amount of diastema expansion to correlate with change in NOSE score (R = - 0.32, P = 0.022). Age and diastema showed a negative correlation (R = - 0.44, P = 0.0019), while INV angle and diastema showed a statistically significant positive correlation (R = 0.28, P = 0.048).RPE showed improvement in both NOSE scores and objective measures of the INV. This may show the possibility of considering RPE in managing resistant pediatric nasal airways. Future studies should include collaboration with pediatric otolaryngologists, with the inclusion of pediatric patients with persistent nasal obstruction.

    View details for DOI 10.1007/s11325-020-02140-y

    View details for Web of Science ID 000546893500002

    View details for PubMedID 32648185

  • How does distraction osteogenesis maxillary expansion (DOME) reduce severity of obstructive sleep apnea? Sleep & breathing = Schlaf & Atmung Iwasaki, T., Yoon, A., Guilleminault, C., Yamasaki, Y., Liu, S. Y. 2019

    Abstract

    OBJECTIVE: Distraction osteogenesis maxillary expansion (DOME) is a reliable method to expand the nasal floor and hard palatal vault in adults with obstructive sleep apnea (OSA). DOME results in a reduction in the apnea-hypopnea index (AHI) and subjective report of improved nasal breathing. Using rhinomanometry augmented computational fluid dynamic (CFD) modeling, we propose a mechanism of how DOME reduces upper airway pharyngeal collapse in adults with OSA.MATERIAL AND METHOD: A retrospective cohort with 20 subjects and mean age of 29.6 ± 8 years who completed DOME at Stanford University from September 2014 to April 2016. Subjects were included if polysomnography, airway morphology, and rhinomanometry were available for use. From the CBCT data, 3D nasal and pharyngeal airway model were generated. Numeric CFD simulation of the airway models were analyzed under the following conditions: (1) the volume of air was flowing at a velocity of 300 cm3/s, (2) the wall surface was not slippery, and (3) the simulations were repeated 1000 times to calculate mean values. Statistical analyses using SPSS v24 software included paired t tests, nonparametric Wilcoxon rank test, Friedman test with Bonferroni correction, and Spearman's correlation coefficients (p < 0.05).RESULTS: Mean AHI improved from 17.8 ± 17.6 to 7.8 ± 7.1 events per hour (p < 0.001). Mean lowest oxygen saturation improved from 88.2 ± 7.2 to 90.9 ± 4.2% (p < 0.05). Mean airflow velocity within the nasal airway decreased from 15.6 ± 7.3 to 7.4 ± 2.1 m/s (p < 0.001) after DOME. Mean negative pressure of the nasal airway, retropalatal airway, oropharyngeal airway, and hypopharyngeal airway is reduced from - 158.4 ± 115.3 to - 48.6 ± 28.7 Pa, from - 174.8 ± 119.9 to - 52.5 ± 31.3 Pa, from - 177.0 ± 118.4 to - 54.9 ± 31.8 Pa and from - 177.9 ± 117.9 to - 56.9 ± 32.1 Pa (p < 0.001), respectively. AHI positively correlated with nasal flow velocity (p < 0.05) and negatively correlated with pharyngeal airway pressure (p < 0.05). ODI was positively correlated with nasal velocity (p < 0.05) and negatively correlated with nasal airway pressure (p < 0.05), retropalatal airway pressure (p < 0.001), oropharyngeal airway pressure (p < 0.001), and hypopharyngeal airway pressure (p < 0.05).CONCLUSION: Anatomic expansion of the nasal floor with widening of the hard palatal vault from DOME is associated with reduction of nasal airflow velocity and downstream reduction of negative pressure in the pharyngeal airway. This dynamic interaction correlates with a reduction in the apnea-hypopnea index (AHI) and Oxygen Desaturation Index (ODI).

    View details for DOI 10.1007/s11325-019-01948-7

    View details for PubMedID 31823220

  • Distraction Osteogenesis Maxillary Expansion (DOME) for adult obstructive sleep apnea patients with narrow maxilla and nasal floor. Sleep medicine Yoon, A., Guilleminault, C., Zaghi, S., Liu, S. Y. 2019

    Abstract

    OBJECTIVES: This study correlates objective and subjective measurements associated with obstructive sleep apnea (OSA) to define the efficacy of Distraction Osteogenesis Maxillary Expansion (DOME) to treat adult OSA patients with narrow maxilla and nasal floor.METHODS: This is a retrospective study reviewing cases from September 2014 through April 2018 with 75 eligible subjects. Inclusion criteria required OSA confirmed by attended polysomnography (PSG). Pre- and Post-operative clinical data were measured at the Stanford Sleep Medicine and Stanford Sleep Surgery Clinics. DOME is a two-step process starting with insertion of custom-fabricated maxillary expanders anchored to the hard palate by mini-implants followed by minimally invasive osteotomies. After maxillary expansion was complete, orthodontic treatment to restore normal occlusion was initiated. Perioperative Apnea-Hypopnea Index (AHI), Epworth Sleepiness Scale (ESS), Nasal Obstruction Symptom Evaluation (NOSE), and Oxygen Desaturation Index (ODI) were measured for 43, 72, 72, and 34 subjects respectively. Statistical analysis was performed using paired T-test with significance set at p-value < 0.05.RESULTS: The mean age of test subjects was 30.5±8.5 years with a gender distribution of 57 males and 18 females. There was a significant reduction in pre and post-operative NOSE score (10.94±5.51 to 3.28±2.89, p<0.0001), mean ESS score (10.48±5.4 to 6.69±4.75, p<0.0001), and AHI (17.65±19.30 to 8.17±8.47, p<0.0001) with an increased percentage of REM sleep (14.4±8.3% to 22.7±6.6%, p=0.0014). No significant adverse effects were identified.CONCLUSIONS: DOME treatment reduced the severity of OSA, refractory nasal obstruction, daytime somnolence, and increased the percentage of REM sleep in this selected cohort of adults OSA patients with narrow maxilla and nasal floor.

    View details for DOI 10.1016/j.sleep.2019.06.002

    View details for PubMedID 31606311

  • Toward a functional definition of ankyloglossia: validating current grading scales for lingual frenulum length and tongue mobility in 1052 subjects. Sleep & breathing = Schlaf & Atmung Yoon, A., Zaghi, S., Weitzman, R., Ha, S., Law, C. S., Guilleminault, C., Liu, S. Y. 2017

    Abstract

    Alterations of the lingual frenulum may contribute to oromyofacial dysfunction, speech and swallowing impediments, underdevelopment of the maxillofacial skeleton, and even predispose to sleep breathing disorder. This study aims to assess the utility of existing instruments for evaluation of restricted tongue mobility, describe normal and abnormal ranges of tongue mobility, and provide evidence in support of a reliable and efficient measure of tongue mobility.A prospective cohort study of 1052 consecutive patients was evaluated during a 3-month period. Age, gender, ethnicity, height, weight, BMI, maximal interincisal mouth opening (MIO), mouth opening with tongue tip to maxillary incisive papillae at roof of mouth (MOTTIP), Kotlow's free-tongue measurement, and presence of severe tongue-tie were recorded. Secondary outcome measures include tongue range of motion deficit (TRMD, difference between MIO and MOTTIP) and tongue range of motion ratio (TRMR, ratio of MOTTIP to MIO).Results indicate that MIO is dependent on age and height; MOTTIP and TRMD are dependent on MIO; Kotlow's free-tongue measurement is an independent measure of free-tongue length and tongue mobility. TRMR is the only independent measurement of tongue mobility that is directly associated with restrictions in tongue function.We propose the use of tongue range of motion ratio as an initial screening tool to assess for restrictions in tongue mobility. "Functional" ankyloglossia can thus be defined and treatment effects followed objectively by using the proposed grading scale: grade 1: tongue range of motion ratio is >80%, grade 2 50-80%, grade 3 < 50%, grade 4 < 25%.

    View details for DOI 10.1007/s11325-016-1452-7

    View details for PubMedID 28097623

  • Distraction Osteogenesis Maxillary Expansion (DOME) for Adult Obstructive Sleep Apnea Patients with High Arched Palate. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Liu, S. Y., Guilleminault, C. n., Huon, L. K., Yoon, A. n. 2017; 157 (2): 345–48

    Abstract

    A narrow maxilla with high arched palate characterizes a phenotype of obstructive sleep apnea (OSA) patients that is associated with increased nasal resistance and posterior tongue displacement. Current maxillary expansion techniques for adults are designed to correct dentofacial deformity. We describe distraction osteogenesis maxillary expansion (DOME) tailored to adult patients with OSA with narrow nasal floor and high arched palate without soft tissue redundancy. DOME is performed with placement of maxillary expanders secured by mini-implants along the midpalatal suture. This minimizes the maxillary osteotomies necessary to re-create sutural separation for reliable expansion at the nasal floor and palatal vault. We report the safety and efficacy profile of the first 20 patients at Stanford who underwent DOME.

    View details for PubMedID 28675100

  • Feasibility of Distraction Osteogenesis Maxillary Expansion (DOME) in patients with persistent nasal obstruction after septoplasty. International forum of allergy & rhinology Liu, S. Y., Yoon, A., Abdelwahab, M., Yu, M. S. 1800

    Abstract

    BACKGROUND: Distraction osteogenesis maxillary expansion (DOME) is an emerging surgical concept for obstructive sleep apnea patients presenting with nasal obstruction, with a high-arched and narrow hard palate. We demonstrate the feasibility of DOME in the treatment of patients with persistent nasal obstruction after primary septoplasty.METHODS: A total of 32 consecutive patients with persistent nasal obstruction after septoplasty who underwent DOME were enrolled in this study. The efficacy of DOME in treating persistent nasal obstruction in septoplasty failure patients was evaluated by using the validated Nasal Obstruction Symptom Evaluation (NOSE) scale. Pre- and postoperative computed tomography (CT) scans were performed to measure the change of nasal floor width after surgery.RESULTS: The NOSE score significantly improved from 13.62±4.74 to 5.15±3.50 (p<0.001) after DOME. The postoperative CT scan showed a significant increase of the nasal floor width from 22.4±4.21 to 28.06±4.52 (p<0.01). No patient experienced major complications, such as wound infection, oronasal fistula, sinusitis, loss of incisor teeth, and malunion.CONCLUSIONS: This study shows that DOME appears to improve persistent nasal obstruction after septoplasty in patients with narrow and high-arched hard palate. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/alr.22931

    View details for PubMedID 34919340

  • Determinants of Sleep-Disordered Breathing During the Mixed Dentition: Development of a Functional Airway Evaluation Screening Tool (FAIREST-6). Pediatric dentistry Oh, J. S., Zaghi, S., Peterson, C., Law, C. S., Silva, D., Yoon, A. J. 2021; 43 (4): 262-272

    Abstract

    Purpose: The purpose of this study was to identify patterns of functional, extraoral, and intraoral examination characteristics that correlate with increased risk of sleep disturbances and develop a functional airway screening tool to help clinicians for early diagnosis of pediatric sleep-disordered breathing. Methods: From March 2018 until March 2019, a cross-sectional study was conducted of 96 mixed dentition children during dental examinations at the UCLA pediatric dental clinic. Outcome measures included a sleep index score by the Sleep Disturbance Scale for Children (SDSC) completed by parents. Clinical assessment tool measurements assessing functional, extraoral, intraoral soft tissue, and intraoral hard tissue determinants were recorded during a routine dental examination by pediatric dental residents. Results: The mean age was 8.9 years (±1.9 years standard deviation), with 46 males and 50 females participating. Mouth-breathing (functional), mentalis strain (extra-oral), tonsillar hypertrophy and ankyloglossia (intraoral soft tissue), dental wear, and narrow palate (intraoral hard tissue) were found to be the most clinically deterministic of higher SDSC scores (P<0.01). A clinical assessment tool for sleep-disordered breathing in pediatric dental patients (FAIREST-6) was developed, comprising these six clinical factors. Conclusions: The FAIREST-6 is a concise and validated clinical assessment tool that may aid in early diagnosis and intervention of pediatric sleep-disordered breathing.

    View details for PubMedID 34467840

  • Correcting Maxillary Molar Root Angulation with the Biocreative System. Journal of clinical orthodontics : JCO Yoon, A., Noh, M. K., Moon, H. W., Chung, K. R., Kim, S. H. 2020; 53 (10): 588-601

    View details for PubMedID 32058325

  • Lingual frenuloplasty with myofunctional therapy: Exploring safety and efficacy in 348 cases. Laryngoscope investigative otolaryngology Zaghi, S., Valcu-Pinkerton, S., Jabara, M., Norouz-Knutsen, L., Govardhan, C., Moeller, J., Sinkus, V., Thorsen, R. S., Downing, V., Camacho, M., Yoon, A., Hang, W. M., Hockel, B., Guilleminault, C., Liu, S. Y. 2019; 4 (5): 489-496

    Abstract

    Ankyloglossia is a condition of altered tongue mobility due to the presence of restrictive tissue between the undersurface of the tongue and the floor of mouth. Potential implications of restricted tongue mobility (such as mouth breathing, snoring, dental clenching, and myofascial tension) remain underappreciated due to limited peer-reviewed evidence. Here, we explore the safety and efficacy of lingual frenuloplasty and myofunctional therapy for the treatment of these conditions in a large and diverse cohort of patients with restricted tongue mobility.Four hundred twenty consecutive patients (ages 29 months to 79 years) treated with myofunctional therapy and lingual frenuloplasty for indications of mouth breathing, snoring, dental clenching, and/or myofascial tension were surveyed. All procedures were performed by a single surgeon using a scissors and suture technique. Safety and efficacy was assessed >2 months postoperatively by means of patient-reported outcome measures.In all, 348 surveys (83% response rate) were completed showing 91% satisfaction rate and 87% rate of improvement in quality of life through amelioration of mouth breathing (78.4%), snoring (72.9%), clenching (91.0%), and/or myofascial tension (77.5%). Minor complications occurred in <5% of cases including complaints of prolonged pain or bleeding, temporary numbness of the tongue-tip, salivary gland issues, minor wound infection or inflammation, and need for revision to excise scar tissue. There were no major complications.Lingual frenuloplasty with myofunctional therapy is safe and potentially effective for the treatment of mouth breathing, snoring, clenching, and myofascial tension in appropriately selected patient candidates. Further studies with objective measures are merited.3.

    View details for DOI 10.1002/lio2.297

    View details for PubMedID 31637291

    View details for PubMedCentralID PMC6793603

  • Lingual frenuloplasty with myofunctional therapy: Exploring safety and efficacy in 348 cases LARYNGOSCOPE INVESTIGATIVE OTOLARYNGOLOGY Zaghi, S., Valcu-Pinkerton, S., Jabara, M., Norouz-Knutsen, L., Govardhan, C., Moeller, J., Sinkus, V., Thorsen, R. S., Downing, V., Camacho, M., Yoon, A., Hang, W. M., Hockel, B., Guilleminault, C., Liu, S. 2019

    View details for DOI 10.1002/lio2.297

    View details for Web of Science ID 000482692400001

  • Impact of Distraction Osteogenesis Maxillary Expansion on the Internal Nasal Valve in Obstructive Sleep Apnea OTOLARYNGOLOGY-HEAD AND NECK SURGERY Abdelwahab, M., Yoon, A., Okland, T., Poomkonsarn, S., Gouveia, C., Liu, S. 2019; 161 (2): 362–67
  • Optimizing mandibular sagittal split of large maxillomandibular advancements for obstructive sleep apnea: patient and surgical factors. Clinical oral investigations Chen, Y. F., Ko, E. C., Zaghi, S., Yoon, A., Williams, R., Riley, R., Liu, S. Y. 2019

    Abstract

    OBJECTIVES: Maxillomandibular advancement (MMA) confers consistent and high rates of surgical success for obstructive sleep apnea (OSA). In the era of value-based medicine, identifying factors that affect the stability of rigid fixation and allow rapid return to function are important targets for improvement. The aim of this study was to identify patient and surgical factors associated with mandibular sagittal split outcomes associated with optimal postoperatively skeletal stability.STUDY DESIGN: Retrospective cohort study.MATERIALS AND METHODS: Forty-six subjects (43 males and 3 females) with postoperative CT scans including three-dimensional reconstruction from which mandibular split patterns could be analyzed were enrolled. Patient factors (age and polysomnographic measures) and surgical factors (extent of osteotomy prior to controlled fracture) were assessed. Outcome measures include (1) bone thickness for rigid fixation and (2) area of passive bony overlap after advancement.RESULTS: Age and severity of disease did not contribute significantly to optimal mandibular split patterns. For optimal area for passive bony overlap and thickness of buccal and lingual plates for rigid fixation, the most important factors are related to surgical technique.CONCLUSIONS: Anterior osteotomy just to the midline of inferior border and horizontal osteotomy to the mandibular foramen are associated with split patterns that result in optimal rigid fixation and passive bony overlap for OSA patients undergoing MMA.CLINICAL RELEVANCE: Optimal surgical technique has the most significant influence in allowing rapid return to function after MMA in patients with OSA.

    View details for DOI 10.1007/s00784-019-03017-5

    View details for PubMedID 31332567

  • Impact of Distraction Osteogenesis Maxillary Expansion on the Internal Nasal Valve in Obstructive Sleep Apnea. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Abdelwahab, M., Yoon, A., Okland, T., Poomkonsarn, S., Gouveia, C., Liu, S. Y. 2019: 194599819842808

    Abstract

    OBJECTIVE: To assess the effect of distraction osteogenesis maxillary expansion (DOME) on objective parameters of the internal nasal valve and correlate findings with subjective outcomes.STUDY DESIGN: Retrospective cohort study.SETTING: Tertiary referral center.SUBJECTS AND METHODS: After Institutional Review Board approval, included subjects were those with obstructive sleep apnea, had undergone DOME from September 2014 to April 2018, and had cone beam computed tomography scans available before and after expansion. Measurement of the internal nasal valve parameters was performed with Invivo6 Software (version 6.0.3). Interrater reliability of all pre- and postexpansion parameters was measured. Patient-reported outcome measures included the Nasal Obstruction and Septoplasty Effectiveness Scale (NOSE) and Epworth Sleepiness Scale scores, and correlation between objective and subjective outcomes were evaluated by Spearman correlation analysis.RESULTS: Thirty-two subjects met inclusion criteria. All showed significant improvement in their subjective outcomes as well as an increase in their internal valve parameters. Significant correlation was observed between increased angles and improvement in postexpansion NOSE score (right angle, P = .024; left angle, P = .029).CONCLUSION: DOME widens the internal nasal valve objectively (dimensions), which correlates significantly with subjective improvement (NOSE scores).

    View details for PubMedID 31084256

  • Surgery in Adults CURRENT CONCEPTS OF SLEEP APNEA SURGERY Blumen, M., Sommer, U., Verse, T., Hamans, E., Liu, S., Guilleminault, C., Yoon, A., Verse, T., DeVries, N. 2019: 147–258
  • Ankyloglossia as a risk factor for maxillary hypoplasia and soft palate elongation: A functional - morphological study. Orthodontics & craniofacial research Yoon, A. J., Zaghi, S. n., Ha, S. n., Law, C. S., Guilleminault, C. n., Liu, S. Y. 2017; 20 (4): 237–44

    Abstract

    To characterize associations between restricted tongue mobility and maxillofacial development.Cross-sectional cohort study of 302 consecutive subjects from an orthodontic practice.Tongue mobility (measured with tongue range of motion ratio [TRMR] and Kotlow free tongue measurement) was correlated with measurements of the maxillofacial skeleton obtained from dental casts and cephalometric radiographs.Tongue range of motion ratio and Kotlow measures of restricted tongue mobility were associated with (i) ratio of maxillary intercanine width to canine arch length, (ii) ratio of maxillary intermolar width to canine arch length and (iii) soft palate length. Restricted tongue mobility was not associated with hyoid bone position or Angle's skeletal classification.Restricted tongue mobility was associated with narrowing of the maxillary arch and elongation of the soft palate in this study. These findings suggest that variations in tongue mobility may affect maxillofacial development.

    View details for PubMedID 28994495

  • Efficacy of Maxillomandibular Advancement Examined with Drug-Induced Sleep Endoscopy and Computational Fluid Dynamics Airflow Modeling. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery Liu, S. Y., Huon, L., Iwasaki, T., Yoon, A., Riley, R., Powell, N., Torre, C., Capasso, R. 2016; 154 (1): 189-195

    Abstract

    To use drug-induced sedation endoscopy (DISE) and computational fluid dynamics (CFD) modeling to study dynamic airway and airflow changes after maxillomandibular advancement (MMA), and how the changes correlate with surgical success based on polysomnography parameters.Retrospective cohort study.University medical center.DISE was rated with the VOTE (velum, oropharynx, tongue, epiglottis) classification, and CFD was used to model airflow velocity and negative pressure exerted on pharyngeal wall. Changes in VOTE score by site and CFD measurements were correlated with perioperative polysomnography outcomes of apnea-hypopnea index (AHI), apnea index (AI), oxygenation desaturation index (ODI), and lowest oxygen saturation.After MMA, 20 subjects (17 males, 3 females) with a mean age of 44 ± 12 years and body mass index of 27.4 ± 4.6 kg/m(2) showed mean decreases in AHI (53.6 ± 26.6 to 9.5 ± 7.4 events/h) and ODI (38.7 ± 30.3 to 8.1 ± 9.2 events/h; P < .001). Improvement in lateral pharyngeal wall collapse during DISE based on VOTE score correlated with the most decrease in AHI (60.0 ± 25.6 to 7.5 ± 3.4 events/h) and ODI (46.7 ± 29.8 to 5.3 ± 2 events/h; P = .002). CFD modeling showed significant positive Pearson correlations between reduction of retropalatal airflow velocity and AHI (r = 0.617, P = .04) and ODI (r = 0.773, P = .005).AHI and ODI improvement after MMA is best correlated with (1) decreased retropalatal airflow velocity modeled by CFD and (2) increased lateral pharyngeal wall stability based on VOTE scoring from DISE.

    View details for DOI 10.1177/0194599815611603

    View details for PubMedID 26740522

  • Efficacy of Maxillomandibular Advancement Examined with Drug-Induced Sleep Endoscopy and Computational Fluid Dynamics Airflow Modeling OTOLARYNGOLOGY-HEAD AND NECK SURGERY Liu, S. Y., Huon, L., Iwasaki, T., Yoon, A., Riley, R., Powell, N., Torre, C., Capasso, R. 2016; 154 (1): 189-195

    Abstract

    To use drug-induced sedation endoscopy (DISE) and computational fluid dynamics (CFD) modeling to study dynamic airway and airflow changes after maxillomandibular advancement (MMA), and how the changes correlate with surgical success based on polysomnography parameters.Retrospective cohort study.University medical center.DISE was rated with the VOTE (velum, oropharynx, tongue, epiglottis) classification, and CFD was used to model airflow velocity and negative pressure exerted on pharyngeal wall. Changes in VOTE score by site and CFD measurements were correlated with perioperative polysomnography outcomes of apnea-hypopnea index (AHI), apnea index (AI), oxygenation desaturation index (ODI), and lowest oxygen saturation.After MMA, 20 subjects (17 males, 3 females) with a mean age of 44 ± 12 years and body mass index of 27.4 ± 4.6 kg/m(2) showed mean decreases in AHI (53.6 ± 26.6 to 9.5 ± 7.4 events/h) and ODI (38.7 ± 30.3 to 8.1 ± 9.2 events/h; P < .001). Improvement in lateral pharyngeal wall collapse during DISE based on VOTE score correlated with the most decrease in AHI (60.0 ± 25.6 to 7.5 ± 3.4 events/h) and ODI (46.7 ± 29.8 to 5.3 ± 2 events/h; P = .002). CFD modeling showed significant positive Pearson correlations between reduction of retropalatal airflow velocity and AHI (r = 0.617, P = .04) and ODI (r = 0.773, P = .005).AHI and ODI improvement after MMA is best correlated with (1) decreased retropalatal airflow velocity modeled by CFD and (2) increased lateral pharyngeal wall stability based on VOTE scoring from DISE.

    View details for DOI 10.1177/0194599815611603

    View details for Web of Science ID 000367745700028

  • Perinatal intermittent hypoxia alters gamma-aminobutyric acid: a receptor levels in rat cerebellum INTERNATIONAL JOURNAL OF DEVELOPMENTAL NEUROSCIENCE Pae, E., Yoon, A. J., Ahuja, B., Lau, G. W., Nguyen, D. D., Kim, Y., Harper, R. M. 2011; 29 (8): 819-826

    Abstract

    Perinatal hypoxia commonly causes brain injury in infants, but the time course and mechanisms underlying the preferential male injury are unclear. Intermittent hypoxia disturbs cerebellar γ-aminobutyric (GABA)-A receptor profiles during the perinatal period, possibly responding to transient excitatory processes associated with GABA(A) receptors. We examined whether hypoxic insults were particularly damaging to the male rodent cerebellum during a specific developmental time window. We evaluated cerebellar injury and GABA(A) receptor profiles following 5-h intermittent hypoxia (IH: 20.8% and 10.3% ambient oxygen, switched every 240s) or room-air control in groups of male and female rat pups on postnatal d 1-2, wk 1, or wk 3. The cerebella were harvested and compared between groups. The mRNA levels of GABA(A) receptors α6, normalized to a house-keeping gene GAPDH, and assessed using real-time reverse-transcriptase PCR assays were up-regulated by IH at wk 1, more extensively in male rats, with sex influencing the regulatory time-course. In contrast, GABA(A) α6 receptor protein expression levels, assessed using Western blot assays, reached a nadir at wk 1 in both male and female rats, possibly indicating involvement of a post-transcriptional mechanism. The extent of cerebellar damage and level of apoptosis, assessed by DNA fragmentation, were greatest in the wk 3 IH-exposed group. The findings suggest partial protection for female rats against early hypoxic insult in the cerebellum, and that down-regulation of GABA(A) receptors, rather than direct neural injury assessed by DNA fragmentation may modify cerebellar function, with potential later motor and other deficits.

    View details for DOI 10.1016/j.ijdevneu.2011.09.003

    View details for Web of Science ID 000297775100005

    View details for PubMedID 21964325