Dr. HyeRan Choo is a Clinical Associate Professor of Plastic and Reconstructive Surgery in the Department of Surgery at Stanford University School of Medicine. She is Director of Neonatal and Pediatric Craniofacial Airway Orthodontics and Dental Sleep Medicine at Lucile Packard Children’s Hospital Stanford. She also directs the Neonatal and Pediatric Craniofacial Airway Orthodontic Fellowship in the Department of Surgery / Division of Plastic and Reconstructive Surgery. She is a Faculty Fellow of the Stanford Byers Center for Biodesign.

After graduating from Seoul National University with a combined degree in Natural Sciences and Dental Surgery in 2002, Dr. Choo received her Dental Medicine degree from the University of Pennsylvania. She completed her orthodontic residency and Masters in Science degree program at the University of Alabama in Birmingham. Following her Craniofacial Fellowship at the Clinical Center of the National Institutes of Health (NIH) / National Institute of Dental and Craniofacial Research (NIDCR), Dr. Choo was recruited as a full-time faculty member at the University of Pennsylvania and The Children’s Hospital of Philadelphia. Dr. Choo joined the faculty of Stanford University School of Medicine in 2016. Dr. Choo is a board-certified craniofacial orthodontist by American Board of Orthodontics since 2008 and became a diplomate of the American Board of Dental Sleep Medicine in 2021.

Dr. Choo’s areas of expertise are non-surgical airway management and facial reconstruction for newborns with cleft and/or Robin Sequence in the Neonatal Intensive Care Unit. Her treatments utilize simple custom-fabricated orthodontic devices to establish a healthy environment to correct neonatal orofacial abnormalities with great respect for natural growth potential of each neonate. She also practices the full scope of pediatric obstructive sleep apnea management as well as orthodontics and dentofacial orthopedics for patients with cleft and craniofacial abnormalities in a multi-disciplinary clinical setting.

Dr. Choo’s treatment philosophy is based on a fundamental understanding of facial growth and oral functions (Biocreative Orthodontic Strategy). Her research focuses on translation of health innovation technology for the advancement of infant orthodontics. She also pioneers the development of skeletal anchorage-based orthodontic and orthopedic treatment strategies for pediatric sleep apnea patients.

Clinical Focus

  • Neonatal Robin Sequence / Obstructive Sleep Apnea / Small Jaw / Feeding & Breathing Difficulties - Stanford Orthodontic Airway Plate
  • Neonatal Cleft Lip and Palate - Biocreative Alveolar Molding Plate
  • Infant Orthodontics - Airway, Molding, and Feeding
  • Non-surgical and Surgical Orthodontics for Obstructive Sleep Apnea
  • Non-surgical and Surgical Orthodontics for Facial Reconstructive Surgery
  • 3D Craniofacial Imaging and Airway Analysis
  • Orthodontics

Administrative Appointments

  • Director, Stanford Orthodontic Airway Plate Treatment Program (SOAP) for neonatal Robin sequence (2023 - Present)
  • Director, Stanford Neonatal and Pediatric Craniofacial Airway Orthodontic Fellowship (2021 - Present)
  • Director, Stanford Neonatal and Pediatric Craniofacial Airway Orthodontics (2019 - Present)

Honors & Awards

  • David Precious Memorial Science Award, International Cleft Lip and Palate Foundation (ICPF) (10/8/2023)
  • National Dental Honor Society, Omicron-Kappa-Upsilon (OKU) (5/17/2004)

Professional Education

  • Diplomate, American Board of Dental Sleep Medicine (2021)
  • Fellowship, Biodesign Faculty Fellowship, Stanford Byers Center for Biodesign, Biodesign (2021)
  • Board Certification, American Board of Orthodontics (2008)
  • Fellowship, Clinical Center, National Institutes of Health (NIH) / National Institute of Dental and Craniofacial Research (NIDCR), Bethesda, MD (2008)
  • MS, Post-Graduate Residency, Orthodontics and Dentofacial Orthopedics, University of Alabama in Birmingham, Birmingham, AL (2007)
  • DMD, Graduate School of Dental Medicine, University of Pennsylvania, Philadelphia, PA (2004)
  • DDS, Undergraduate School of Natural Sciences & Graduate School of Dental Surgery, Seoul National University, Seoul, South Korea (2002)

All Publications

  • Presurgical Reduction of the Cleft Palate: Serendipitous Benefit of the Stanford Orthodontic Airway Plate Treatment (SOAP) for Infants with Robin Sequence. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association Kim, J. W., Wan, A., Kim, J. Y., Choo, H. 2024: 10556656241261846


    Narrowing of the palatal cleft is often observed in infants with Robin sequence (RS) treated with the Stanford Orthodontic Airway Plate treatment (SOAP) even though SOAP is utilized primarily to establish airway patency. The current study quantified dimensional changes of the cleft palate (CP) in infants with RS treated with SOAP.A retrospective chart review.Infants with RS and CP who completed SOAP and had maxillary arch models at both pre- and post-treatment time points at a single tertiary referral hospital between September 2019 and July 2023.Maxillary arch models were measured and analyzed using Bivariate statistical analysis.Seventeen infants were included in the study. The median age (min, max) was 6.7 weeks (1.1, 21.9) at pre-treatment and 26.6 weeks (18.7, 37.0) at post-treatment. The median Obstructive Apnea Hypopnea Index was 36.2 events/hour (8.1, 103.1) at pre-treatment and 4.1 events/hour (1.9, 8.6) at post-treatment. The pre-treatment width of CP decreased by an average (± standard diviation) of 6.37 mm (± 3.55, p < 0.001) at post-treatment. The ratio of the posterior cleft width to the total maxillary arch width decreased from 40% (± 9.1) at pre-treatment to 22% (± 11) at post-treatment (p < 0.001).The dimensions of CP reduced significantly during SOAP in infants with RS and CP treated for their severe upper airway obstruction. The findings highlight a potential benefit of SOAP that may contribute favorably to the palate repair surgery.

    View details for DOI 10.1177/10556656241261846

    View details for PubMedID 38881285

  • Weight Gain of Infants with Robin Sequence Treated Nonsurgically Using the Stanford Orthodontic Airway Plate (SOAP): 1-Year Follow-Up. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association Choo, H., Davis, A. S., Bain, L. C., Ahn, H. 2024: 10556656241233239


    To identify weight gain trends of infants with Robin sequence (RS) treated by the Stanford Orthodontic Airway Plate treatment (SOAP).Retrospective longitudinal cohort study.Single tertiary referral hospital.Eleven infants with RS treated with SOAP.Nonsurgical SOAP.Body weight, Weight-for-age (WFA) Z-scores, and WFA percentiles at birth (T0), SOAP delivery (T1), SOAP graduation (T2), and 12-months old (T3).Between T0 and T1, the weight increased but the WFA percentile decreased from 36.5% to 15.1%, and the Z-score worsened from -0.43 to -1.44. From T1 to T2, the percentile improved to 22.55% and the Z-score to -0.94. From T2 to T3, the percentile and the Z-scores further improved to 36.59% and -0.48, respectively.SOAP provided infants experiencing severe respiratory distress and oral feeding difficulty with an opportunity to gain weight commensurate with the WHO healthy norms without surgical intervention.

    View details for DOI 10.1177/10556656241233239

    View details for PubMedID 38373407

  • Biocreative Alveolar Molding Plate Treatment (BioAMP) for neonatal unilateral cleft lip and palate with excessively wide alveolar cleft and maxillary arch width. Korean journal of orthodontics Choo, H., Ahn, H. 2024; 54 (1): 69-73


    Since its inception in Europe in the 1950s, alveolar molding treatment for neonates with complete cleft lip and palate has undergone significant evolution in both design and application methodology, demonstrating effectiveness in normalizing the alveolar cleft and nasal shape. However, excessively wide alveolar clefts accompanied by disproportionately wide total maxillary arch pose significant challenges when utilizing conventional alveolar molding methods involving cyclical adding and grinding of acrylic on molding plates. The current report introduces a novel alveolar molding method named Biocreative Alveolar Molding Plate Treatment (BioAMP), which can normalize the maxillary alveolar cleft and arch shape without laborious conventional acrylic procedures. BioAMP sets the target arch form and provides unrestricted space for natural growth of the maxillary alveolar bones while systematically reducing the total maxillary arch width in precise increments. Two exemplary cases are presented as proof-of-concept, showcasing the clinical innovation of BioAMP.

    View details for DOI 10.4041/kjod23.163

    View details for PubMedID 38268462

  • Effects of daily versus weekly teriparatide for medication-related osteonecrosis of the jaw: A case-control study. Oral diseases Kim, K. M., Kim, S., Hwang, H., Kim, H. Y., Kim, D., Park, J. H., Choo, H., Kim, J. W. 2023


    Medication-related osteonecrosis of the jaw (MRONJ) is uncommon but can result in severe destruction of the jaw. This case-control study investigated the therapeutic effects of daily or weekly administration of teriparatide in the management of MRONJ using a cohort for osteonecrosis of the jaw.Patients who were diagnosed with MRONJ and consented to teriparatide administration were assigned either to a group of daily injection or of weekly injection and completed a 4-week course of injection preoperatively and at least an 8-week course postoperatively. The control group received either the intraoperative rhBMP treatment (CG_BMP) or no additional perioperative treatment (CG_noBMP). The state of MRONJ was evaluated 2 months (T1) and 6 months (T2) postoperatively for all participants.Either group of daily injection (8.35 weeks ± 1.58; n = 17) or weekly injection (9.17 ± 3.79; n = 12) showed significantly faster healing than those of CG_BMP (14.40 ± 6.08; n = 25) or CG_noBMP (15.79 ± 9.79; n = 39). MRONJ was resolved completely in 24 out of 29 participants who completed the course of teriparatide injections, whereas 46.9% of CG showed delayed resolution. Multiple regression analysis indicated 7.50 times (95% CI, 1.77-31.82) more likelihood of complete resolution of MRONJ for participants with teriparatide injections.A course of daily or weekly administration of teriparatide injections may improve treatment outcomes for patients with MRONJ.

    View details for DOI 10.1111/odi.14801

    View details for PubMedID 37927178

  • Miniscrews position for a tissue bone borne palatal C-expander affects the displacement pattern of nasomaxillary complex: a finite element study. Scientific reports Choi, J., Choo, H., Kim, M., Chung, K., Kim, S. 2023; 13 (1): 17135


    This study aimed to evaluate the difference in expansion patterns based on the position of miniscrews for a tissue-bone-borne palatal C-expander using a finite element method. Ten expansion models were examined, each representing a different position of miniscrews on the palate. Models A and B had miniscrews symmetrically placed 7mm and 15mm below the cementoenamel junction (CEJ), respectively. Models C to J had miniscrews positioned in a triangular manner at 7mm and 15mm below CEJ. Stress, displacement, angular changes of the bone and teeth, and changes in the nasomaxillary complex were measured using elastoplastic behavior models through static-nonlinear simulation employing an implicit method. The anterior and posterior parts of paramidpalatal suture area were identified as ANT, TPS-M, and TPS-L, and their ratio was assessed. Model A, which featured three miniscrews located 7mm below the CEJ, exhibited the least molar inclination and the smallest amount of skeletal expansion. Model I, with two miniscrews placed between the first and second molars, demonstrated the greatest lateral displacement at point N on the nasal cavity wall, along with the smallest ratio of ANT to TPS-M or TPS-L. This finding suggests that the posterior expansion of the palate in relation to the anterior expansion was maximized. The results of this study indicate that strategic positioning of miniscrews is effective in achieving various expansion patterns based on the targeted correction areas within the nasomaxillary complex.

    View details for DOI 10.1038/s41598-023-44432-9

    View details for PubMedID 37816861

  • Development and systematic characterization of GelMA/alginate/PEGDMA/xanthan gum hydrogel bioink system for extrusion bioprinting. Biomaterials Li, J., Moeinzadeh, S., Kim, C., Pan, C. C., Weale, G., Kim, S., Abrams, G., James, A. W., Choo, H., Chan, C., Yang, Y. P. 2022; 293: 121969


    Gelatin methacryloyl (GelMA)/alginate-based hydrogels have shown great promise in bioprinting, but their printability is limited at room temperature. In this paper, we present our development of a room temperature printable hydrogel bioink by introducing polyethylene glycol dimethacrylate (PEGDMA) and xanthan gum into the GelMA/alginate system. The inclusion of PEGDMA facilitates tuning of the hydrogel's mechanical property, while xanthan gum improves the viscosity of the hydrogel system and allows easy extrusion at room temperature. To fine-tune the mechanical and degradation properties, methacrylated xanthan gum was synthesized and chemically crosslinked to the system. We systematically characterized this hydrogel with attention to printability, strut size, mechanical property, degradation and cytocompatibility, and achieved a broad range of compression modulus (∼10-100 kPa) and degradation profile (100% degradation by 24 h-40% by 2 weeks). Moreover, xanthan gum demonstrated solubility in ionic solutions such as cell culture medium, which is essential for biocompatibility. Live/dead staining showed that cell viability in the printed hydrogels was over 90% for 7 days. Metabolic activity analysis demonstrated excellent cell proliferation and survival within 4 weeks of incubation. In summary, the newly developed hydrogel system has demonstrated distinct features including extrusion printability, widely tunable mechanical property and degradation, ionic solubility, and cytocompatibility. It offers great flexibility in bioprinting and tissue engineering.

    View details for DOI 10.1016/j.biomaterials.2022.121969

    View details for PubMedID 36566553

  • Split orthodontic airway plate: An innovation to the utilization method of conventional orthodontic airway plate for neonates with Robin sequence KOREAN JOURNAL OF ORTHODONTICS Choo, H., Kim, S., Ahn, H., Poets, C. F., Chung, K. 2022; 52 (4): 308-312


    Since the emergence of neonatal infant orthodontics for treatments of cleft lip and palate with or without Robin sequence (RS) in Europe in the 1950s, advancements in design and scope of its application have been remarkable. As the first institution to adopt orthodontic airway plate (OAP) treatment in the United States in 2019, we saw a need for innovation of the original design to streamline the most labor-intensive and time-consuming aspects of OAP utilization. A solution is introduced using a systematic split expansion mechanism to re-size the OAP periodically to accommodate the neonate's maxillary growth. To date, seven RS patients have received this modified treatment protocol at our institution. Each patient completed full treatment using only one OAP. This innovative utilization method is aptly named the split orthodontic airway plate (S-OAP). Details of the S-OAP and its modifications from conventional OAP are reported.

    View details for DOI 10.4041/kjod21.238

    View details for Web of Science ID 000830678100008

    View details for PubMedID 35466088

  • New Frontier in Advanced Dentistry: CBCT, Intraoral Scanner, Sensors, and Artificial Intelligence in Dentistry. Sensors (Basel, Switzerland) Kim, S., Kim, K. B., Choo, H. 2022; 22 (8)


    The advancement of science and technology has brought innovation in the dental field [...].

    View details for DOI 10.3390/s22082942

    View details for PubMedID 35458927

  • Bio-Exercise (BioEx) - A biocreative orofacial myofunctional therapy: preliminary cephalometric study and clinical application. Dental press journal of orthodontics Lim, L., Choo, H., Eto, L. F., Chung, K., Kim, S. 2022; 27 (2): e2220367


    OBJECTIVE: To introduce newly structured and developed orofacial myofunctional therapy (OFMFT) protocols named Bio-Exercise (BioEx), and evaluate the treatment effect of this method, using lateral cephalometric analysis on malocclusion with low tongue posture in young patients.METHODS: A retrospective preliminary study was performed using orthodontic records from 28 patients (mean age of 8.41±1.45-year-old, 13 males, 15 females) treated with BioEx therapy using tongue elevators for 18.14±9.04 months (range: 6 to 37 months). Pretreatment (T0) and post-BioEx therapy (T1) lateral cephalograms were subsequently analyzed for tongue posture changes by linear, anteroposterior and vertical measurements. The data were analyzed by paired t-test, considering a 5% significance level.RESULTS: The tongue length (TGL) and tongue height (TGH) increased statistically significant between T0 and T1. The decrease of the dorsum of the tongue perpendicular to the palatal plane (Td-PP value) was statistically significant. The increase of the tip of the tongue perpendicular to the pterygomaxillary vertical line (TT-PMV) was not statistically significant.CONCLUSIONS: These preliminary cephalometric results indicate that BioEx can be an effective OFMFT modality in increasing the tonicity of the tongue muscles to establish more normalized tongue position at rest.

    View details for DOI 10.1590/2177-6709.27.2.e2220367.oar

    View details for PubMedID 35613244

  • Cross-species comparisons reveal resistance of human skeletal stem cells to inhibition by non-steroidal anti-inflammatory drugs. Frontiers in endocrinology Goodnough, L. H., Ambrosi, T. H., Steininger, H. M., Butler, M. G., Hoover, M. Y., Choo, H., Van Rysselberghe, N. L., Bellino, M. J., Bishop, J. A., Gardner, M. J., Chan, C. K. 2022; 13: 924927


    Fracture healing is highly dependent on an early inflammatory response in which prostaglandin production by cyclo-oxygenases (COX) plays a crucial role. Current patient analgesia regimens favor opioids over Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) since the latter have been implicated in delayed fracture healing. While animal studies broadly support a deleterious role of NSAID treatment to bone-regenerative processes, data for human fracture healing remains contradictory. In this study, we prospectively isolated mouse and human skeletal stem cells (SSCs) from fractures and compared the effect of various NSAIDs on their function. We found that osteochondrogenic differentiation of COX2-expressing mouse SSCs was impaired by NSAID treatment. In contrast, human SSCs (hSSC) downregulated COX2 expression during differentiation and showed impaired osteogenic capacity if COX2 was lentivirally overexpressed. Accordingly, short- and long-term treatment of hSSCs with non-selective and selective COX2 inhibitors did not affect colony forming ability, chondrogenic, and osteogenic differentiation potential in vitro. When hSSCs were transplanted ectopically into NSG mice treated with Indomethacin, graft mineralization was unaltered compared to vehicle injected mice. Thus, our results might contribute to understanding species-specific differences in NSAID sensitivity during fracture healing and support emerging clinical data which conflicts with other earlier observations that NSAID administration for post-operative analgesia for treatment of bone fractures are unsafe for patients.

    View details for DOI 10.3389/fendo.2022.924927

    View details for PubMedID 36093067

  • Disruptive Therapy Using a Nonsurgical Orthodontic Airway Plate for the Management of Neonatal Robin Sequence: 1-Year Follow-up. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association Choo, H., Galera, R. I., Balakrishnan, K., Lin, H. C., Ahn, H., Lorenz, P., Khosla, R. K., Profit, J., Poets, C. F., Lee, J. S. 2022: 10556656221076980


    We recently published the 3-month follow-up of 2 neonates with Robin sequence whose mandibular hypoplasia and restricted airway were successfully treated with an orthodontic airway plate (OAP) without surgical intervention. Both infants were successfully weaned off the OAP after several months of continuous use. We present the course of OAP treatment in these patients with a focus on breathing, feeding, and facial growth during their first year of life. Both infants demonstrated stable mandibular projection, resolution of obstructive sleep apnea, and normal development.

    View details for DOI 10.1177/10556656221076980

    View details for PubMedID 35167404

  • Root proximity of the anchoring miniscrews of orthodontic miniplates in the mandibular incisal area: Cone-beam computed tomographic analysis. Korean journal of orthodontics Jeong, D., Oh, S. H., Choo, H., Choi, Y., Kim, S., Lee, J., Hwang, E. 2021; 51 (4): 231-240


    Objective: This outcome analysis study evaluated the actual positions of the orthodontic miniplate and miniplate anchoring screws (MPASs) and the risk factors affecting adjacent anatomic structures after miniplate placement in the mandibular incisal area.Methods: Cone-beam computed tomographic images of 97 orthodontic miniplates and their 194 MPASs (diameter, 1.5 mm; length, 4 mm) in patients whose miniplates provided sufficient clinical stability for orthodontic treatment were retrospectively reviewed. For evaluating the actual positions of the miniplates and analyzing the risk factors, including the effects on adjacent roots, MPAS placement height (PH), placement depth (PD), plate angle (PA), mental fossa angle (MA), and root proximity were assessed using the paired t-test, analysis of variance, and generalized linear model and regression analyses.Results: The mean PDs of MPASs at positions 1 (P1) and 2 (P2) were 2.01 mm and 2.23 mm, respectively. PA was significantly higher in the Class III malocclusion group than in the other groups. PH was positively correlated with MA and PD at P1. Of the 97 MPASs at P1, 49 were in the no-root area and 48 in the dentulous area; moreover, 19 showed a degree of root contact (19.6%) without root perforation. All MPASs at P2 were in the no-root area.Conclusions: Positioning the miniplate head approximately 1 mm lower than the mucogingival junction is highly likely to provide sufficient PH for the P1- MPASs to be placed in the no-root area.

    View details for DOI 10.4041/kjod.2021.51.4.231

    View details for PubMedID 34275879

  • A Systematic Review of Mandibular Distraction Osteogenesis Versus Orthodontic Airway Plate for Airway Obstruction Treatment in Pierre Robin Sequence. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association Abbas, D. B., Lavin, C., Fahy, E. J., Choo, H., Truong, M. T., Bruckman, K. C., Khosla, R. K., Lorenz, H. P., Momeni, A., Wan, D. C. 2021: 10556656211011886


    OBJECTIVE: Mandibular distraction osteogenesis (MDO) is frequently performed to address airway obstruction in patients with Pierre Robin sequence (PRS), though more recently the technique of orthodontic airway plating (OAP) has gained traction. We aimed to evaluate OAP compared to MDO for airway obstruction in PRS.DESIGN: A systematic literature search across PubMed, Embase, and Google Scholar identified all studies published in English, which involved MDO or any form of OAP as treatments for PRS. All relevant articles were reviewed in detail and reported on, adhering to PRISMA guidelines.MAIN OUTCOME MEASURES: Airway (tracheostomy avoidance, decannulation rate), feeding (full oral feeding tolerance).RESULTS: Literature search identified 970 articles, of which 42 MDO studies and 9 OAP studies met criteria for review. A total of 1159 individuals were treated with MDO, and 322 individuals were treated with OAP. Primary outcomes appear similar for MDO and OAP at face value; however, this must be interpreted with different pretreatment contexts in mind.CONCLUSIONS: Orthodontic airway plating may be considered for airway obstruction in PRS, as some airway-related and feeding-related outcomes appear similar with MDO, per existing evidence in the literature. However, since PRS severity differed between studies, OAP cannot be uniformly considered a replacement for MDO. Further research is required to more comprehensively assess these treatment modalities inclusive of metrics that allow for direct comparison.

    View details for DOI 10.1177/10556656211011886

    View details for PubMedID 34075816

  • Evaluation of strategic uprighting of the mandibular molars using an orthodontic miniplate and a nickel-titanium reverse curve arch wire: Preliminary cephalometric study. Korean journal of orthodontics Park, J., Choo, H., Choi, J., Chung, K., Kim, S. 2021; 51 (3): 179-188


    Objective: To evaluate the overall treatment effects in terms of the amount of uprighting with changes in the sagittal and vertical positions of mandibular molars after applying an orthodontic miniplate with a nickel-titanium (NiTi) reverse curve arch wire (biocreative reverse curve [BRC] system).Methods: A total of 30 female patients (mean age, 25.99 ± 8.96 years) were treated with the BRC system (mean BRC time, 10.3 ± 4.07 months). An I-shaped C-tube miniplate (Jin Biomed) was placed at the labial aspect for the alveolar bone of the mandibular incisors. A 0.017 * 0.025-inch NiTi reverse curve arch wire was engaged at the C-tube mini-plate anteriorly and the first and second premolars and molars posteriorly in the mandibular arch. Pre- and post-BRC lateral cephalograms were analyzed. A paired t-test was used to analyze the treatment effects of BRC.Results: The mandibular second molars were intrusively uprighted successfully by the BRC system. Distal uprighting with a controlled vertical dimension was noted on the first molars when they remained engaged in the BRC and the distal ends of the arch wire were laid on the second molars. The mandibular first and second premolars showed a slight extrusion. The changes in the mandibular incisors were unremarkable, while the mandibular molar angulation improved significantly. The lower occlusal plane rotated counterclockwise (MP-LOP: 1.13° ± 2.60°).Conclusions: The BRC system can provide very effective molar uprighting without compromising the position of the mandibular anterior teeth.

    View details for DOI 10.4041/kjod.2021.51.3.179

    View details for PubMedID 33984225

  • Nonsurgical Orthodontic Airway Plate Treatment for Newborns With Robin Sequence. The Cleft palate-craniofacial journal : official publication of the American Cleft Palate-Craniofacial Association Choo, H., Khosla, R. K., Meister, K. D., Wan, D. C., Lin, H. C., Feczko, R., Bruckman, K., Hopkins, E., Truong, M. T., Lorenz, H. P. 2021: 10556656211007689


    Despite promising outcomes for >50 years, nonsurgical orthodontic airway plates (OAP) are only infrequently offered for babies with Robin sequence in a few parts of the world. This article demonstrates possibility of providing functional improvement using an OAP to help these babies overcome their functional and structural difficulties on their own. Two consecutively treated cases are presented exemplifying that OAP treatment that had originated from Europe is reproducible and effective in an institution in the United States.

    View details for DOI 10.1177/10556656211007689

    View details for PubMedID 33845627

  • Finite element analysis of C-expanders with different vertical vectors of anchor screws. American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics Choi, J., Choo, H., Oh, S. H., Park, J., Chung, K., Kim, S. 2021


    INTRODUCTION: C-expanders are tooth-borne and bone-borne maxillary expanders that are anchored by 6 orthodontic miniscrews, 3 on each side of the palate. The purpose of the study was to investigate the effect of C-expanders on the circummaxillary sutures and bucco-palatal axis of teeth in 3-dimensional finite element analyses when anchor screw vectors are different.METHODS: Five expansion models were studied on the basis of the vertical positions of anchor screws on the palate. Anchor screws for models A, B, and C were placed symmetrically at 4mm, 7mm, and 15mm below the cementoenamel junction (CEJ), respectively. Anchor screws for models D and E were placed asymmetrically at 4mm and 15mm below CEJ and 7mm and 15mm below CEJ, respectively. Stress, displacement, and angular changes of the bone and teeth were measured in elastoplastic behavior models using a static-nonlinear simulation in an implicit method.RESULTS: Symmetrical and asymmetrical anchor screw placement with different vertical vectors were compared using finite element analyses on 5 models.CONCLUSIONS: Using different vectors of anchor screws for C-expanders does change the pattern of palatal expansion (null hypothesis was rejected). The current investigation presents a promising future of controlled asymmetric skeletal maxillary expansion when asymmetric maxillary architecture needs to be corrected for successful orthodontic outcomes without involving orthognathic surgeries.

    View details for DOI 10.1016/j.ajodo.2020.02.024

    View details for PubMedID 33762139

  • Use of C-Tube Microplates for Controlling the Vertical Dimension During Maxillary Incisor Intrusion. Journal of clinical orthodontics : JCO Noh, M. K., Seo, K. W., Choo, H. n., Chung, K. R., Kim, S. H. 2019; 53 (7): 414–25

    View details for PubMedID 31648217

  • The biocreative strategy. Part 4: Molar distalization in nonextraction treatment. Journal of clinical orthodontics : JCO Chung, K. R., Kim, Y., Choo, H., Kim, S. H., Nelson, G. 2018; 52 (9): 462-475

    View details for PubMedID 30256221

  • Non-extraction correction of Class II malocclusion using Biocreative Therapy Skeletal Anchorage in Orthodontic Treatment of Class II Malocclusion Chung, K., Choo, H., Kim, S. Mosby Elsevier. 2014; 1: 239–243
  • Modified Technique of Presurgical Infant Maxillary Orthopedics for Complete Bilateral Cleft Lip and Palate PLASTIC AND RECONSTRUCTIVE SURGERY Choo, H., Maguire, M., Low, D. W. 2012; 129 (1): 244–48


    This article introduces technical modifications to the conventional presurgical infant maxillary orthopedics device for newborns with complete bilateral cleft lip and palate, providing procedural simplicity and efficiency as well as therapeutic efficacy. The modifications incorporate a wax block-out on the stone model prior to device fabrication in a manner that the need for periodic acrylic addition and removal is not required, and thus eliminates the risk of natural maxillary growth restriction during infant maxillary orthopedics treatment. The premaxilla is completely excluded from the acrylic palatal plate and is repositioned primarily by the bilateral labial tape alone. In addition, nasal stent wires are installed on the same day of the palatal plate delivery to establish a tripod-like retention mechanism for the intraoral device to be able to replace the conventional mechanical lock-type retention methods. Applying these modifications, infant maxillary orthopedics treatment objectives for bilateral cleft lip and palate can be successfully achieved within 8 weeks of treatment, and the definitive primary cleft lip repair can be performed within 3-4 months of infant maxillary orthopedics treatment at our Center.

    View details for DOI 10.1097/PRS.0b013e318230c84c

    View details for Web of Science ID 000298857100097

    View details for PubMedID 22186513

  • Modified Technique of Presurgical Infant Maxillary Orthopedics for Complete Unilateral Cleft Lip and Palate PLASTIC AND RECONSTRUCTIVE SURGERY Choo, H., Maguire, M., Low, D. W. 2012; 129 (1): 249–52


    This article introduces a modified device fabrication and facial taping method that increases the efficiency and efficacy of presurgical infant maxillary orthopedic therapy for babies born with complete cleft lip and palate. Interarch and intra-arch relationships of the maxillary and mandibular dental arches were evaluated on mounted stone models before and after treatment. The palatal plate device was custom-fabricated in a manner that bypassed the need for periodic acrylic addition and removal, thereby eliminating the risk of natural maxillary growth restriction during therapy. Elastic labial tapes were fabricated and applied in a configuration that mimicked normal function of the orbicularis oris muscle. A nasal stent wire was utilized from the initiation of therapy to enhance intraoral retention and stability of the device. Examples of infants undergoing a unilateral complete cleft lip and palate treatment protocol are presented. Treatment objectives were achieved within 7 to 8 weeks of therapy for patients who had an initial alveolar cleft size more than 10 to 12 mm. The modified protocol of presurgical infant maxillary orthopedic therapy is an effective and efficient treatment modality in reversing the pre-existing orofacial dysmorphism by redirecting the infant's natural growth.

    View details for DOI 10.1097/PRS.0b013e318230c8bb

    View details for Web of Science ID 000298857100098

    View details for PubMedID 22186514

  • Treatment outcome analysis of speedy surgical orthodontics for adults with maxillary protrusion AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS Choo, H., Heo, H., Yoon, H., Chung, K., Kim, S. 2011; 140 (6): E251–E262


    The purposes of this study were to quantify the treatment outcomes of speedy surgical orthodontic treatment for adults with maxillary protrusion and to identify the key factors influencing the efficacy of speedy surgical orthodontic biomechanics.Twenty-four adults with maxillary or bimaxillary protrusion were treated with speedy surgical orthodontics, including maxillary perisegmental corticotomy followed by the orthopedic en-masse retraction against C-palatal miniplate anchorage. The average total treatment time was 20 months (range, 11-42 months). Lateral cephalograms were taken at pretreatment, just after the perisegmental corticotomy, and at posttreatment to evaluate the skeletal and soft-tissue changes. The Pearson correlation analysis was used to identify the relationships between hard-tissue, soft-tissue, and perisegmental corticotomy variables.The maxillary central incisors were retracted by 9.19 ± 0.31 mm and retroclined by 19.73° ± 1.17°. The change of the maxillary alveolar ridge angle was 13.97° ± 1.04°. The extrusion tendency of the retracted maxillary incisors was minimal, measured as 1.17 ± 0.36 mm. The width of the buccal corticotomy showed statistically significant correlations with the angular change of the maxillary central incisors and the maxillary alveolar ridge angle. The retrusion of the maxillary central incisors and the maxillary alveolar ridge angle were the 2 hard-tissue variables that most closely correlated with retrusion of the upper lip.Speedy surgical orthodontic treatment can be an effective modality for adults with severe maxillary protrusion.

    View details for DOI 10.1016/j.ajodo.2011.06.029

    View details for Web of Science ID 000297994200001

    View details for PubMedID 22133959

  • Novel application of the 2-piece orthodontic C-implant for temporary crown restoration after orthodontic treatment. American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics Jeong, D. M., Choi, B., Choo, H., Kim, J. H., Chung, K. R., Kim, S. H. 2011; 140 (4): 569-79


    This article reports the use of an orthodontic mini-implant for a temporary crown restoration in a small edentulous space after limited orthodontic treatment.Two clinical cases are presented: a 23-year-old woman and a 14-year-old boy. In the adult patient, a 2-piece orthodontic C-implant (Cimplant, Seoul, Korea) was placed in a 3-mm wide edentulous space to build up a temporary crown restoration after a short orthodontic treatment to regain space for a missing mandibular right permanent lateral incisor. In the boy, a C-implant was placed in the space resulting from an avulsed maxillary right permanent lateral incisor to prevent aggressive alveolar bone resorption after dental trauma. Both patients were followed for more than 4 years of retention to evaluate the stability of the temporary crown restoration built up on the orthodontic mini-implants.Both patients had successful long-term results, confirmed by clinical and radiographic examinations. Both were pleased with the results and plan to retain the orthodontic mini-implant temporary crown restoration until they are ready for a permanent restoration later.A 2-piece orthodontic C-implant system can be used to maintain edentulous space after active orthodontic treatment.

    View details for DOI 10.1016/j.ajodo.2009.10.051

    View details for PubMedID 21967946

  • Histologic assessment of the biological effects after speedy surgical orthodontics in a beagle animal model: a preliminary study KOREAN JOURNAL OF ORTHODONTICS Kim, H., Lee, Y., Park, Y., Chung, K., Kang, Y., Choo, H., Kim, S. 2011; 41 (5): 361–70
  • The effects of different pilot-drilling methods on the mechanical stability of a mini-implant system at placement and removal: a preliminary study KOREAN JOURNAL OF ORTHODONTICS Cho, I., Choo, H., Kim, S., Shin, Y., Kim, D., Kim, S., Chung, K., Huang, J. C. 2011; 41 (5): 354–60
  • Atypical orthodontic extraction pattern managed by differential en-masse retraction against a temporary skeletal anchorage device in the treatment of bimaxillary protrusion AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS Chung, K., Choo, H., Lee, J., Kim, S. 2011; 140 (3): 423–32


    This report introduces an innovative treatment approach of selecting atypical and unconventional teeth for orthodontic extraction without compromising the quality of treatment outcomes by using temporary skeletal anchorage devices in patients with bimaxillary protrusion. Both patients introduced in this report had solid Class I molar relationships with bimaxillary anterior protrusion without facial or dental midline asymmetry. Their chief concerns were significant facial convexity, which conventionally requires the extraction of all 4 first premolars. However, 3 second premolars and 1 first premolar were removed in the first patient, and 2 second premolars and 2 first premolars were removed in the second patient. All second premolars extracted had previously had root canal treatment and large prosthodontic restorations, which resulted in a compromised short lifespan of the teeth relative to the natural dentition. To manage these cases of asymmetric extraction space in a symmetric dental and skeletal environment, 2 mini-implants were placed in the posterior maxillary interradicular spaces, 1 on each side. Despite the unusual asymmetric extraction of teeth, superimposition of the pretreatment and posttreatment cephalometric tracings shows excellent treatment outcomes of facial convexity reduction by asymetric maximum retraction of the anterior teeth with no change in the molar relationships.

    View details for DOI 10.1016/j.ajodo.2009.08.036

    View details for Web of Science ID 000294678700031

    View details for PubMedID 21889088

  • Replacing a failed mini-implant with a miniplate to prevent interruption during orthodontic treatment. American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics Lee, J. H., Choo, H., Kim, S. H., Chung, K. R., Giannuzzi, L. A., Ngan, P. 2011; 139 (6): 849-57


    When mini-implants fail during orthodontic treatment, there is a need to have a backup plan to either replace the failed implant in the adjacent interradicular area or wait for the bone to heal before replacing the mini-implant. We propose a novel way to overcome this problem by replacement with a miniplate so as not to interrupt treatment or prolong treatment time.The indications, advantages, efficacy, and procedures for switching from a mini-implant to a miniplate are discussed. Two patients who required replacement of failed mini-implants are presented. In the first patient, because of the proximity of the buccal vestibule to the mini-implant, it was decided to replace the failed mini-implant by an I-shaped C-tube miniplate. In the second patient, radiolucencies were found around the failed mini-implants, making the adjacent alveolar bone unavailable for immediate placement of another mini-implant. In addition, the maxillary sinus pneumatization was expanded deeply into the interradicular spaces; this further mandated an alternative placement site. One failed mini-implant was examined under a scanning electron microscope for bone attachment.Treatment was completed in both patients after replacement with miniplates without interrupting the treatment mechanics or prolonging the treatments. Examination under the scanning electron microscope showed partial bone growth into the coating pores and titanium substrate interface even after thorough cleaning and sterilization.Replacement with a miniplate is a viable solution for failed mini-implants during orthodontic treatment. The results from microscopic evaluation of the failed mini-implant suggest that stringent guidelines are needed for recycling used mini-implants.

    View details for DOI 10.1016/j.ajodo.2009.08.032

    View details for PubMedID 21640893

  • Advanced Applications of Cone Beam Computed Tomography in Orthodontics Seminars in Orthodontics Mah, J. K., Liu, Y., Huang, J. C., Choo, H. 2011; 17 (1): 57-71
  • Class III Correction Using Biocreative Therapy (C-Therapy) Seminars in Orthodontics Chung, K., Kim, S., Choo, H. 2011; 17 (2): 108-123
  • Timely relocation of mini-implants for uninterrupted full-arch distalization AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS Chung, K., Choo, H., Kim, S., Ngan, P. 2010; 138 (6): 839–49


    This report describes a novel concept of relocating orthodontic mini-implants during dental distalization to provide unrestricted distal movement of the full maxillary dentition. The patient was an 18-year old Korean woman with a full-step Class II Division 1 malocclusion and mandibular deficiency. Mini-implants were initially placed bilaterally between the maxillary second premolar and the first molar. Sliding jigs were used to distalize the maxillary first and second molars. After the maxillary molars were distalized to a Class I molar relationship, the mini-implants were removed and immediately relocated distally to provide space for retraction of the anterior teeth. The occlusion was completed with Class I molar and canine relationships with optimal overjet and overbite. The 2-year posttreatment records showed a stable treatment with retention.

    View details for DOI 10.1016/j.ajodo.2009.02.035

    View details for Web of Science ID 000284940000046

    View details for PubMedID 21130344

  • Practical applications of cone-beam computed tomography in orthodontics JOURNAL OF THE AMERICAN DENTAL ASSOCIATION Mah, J. K., Huang, J. C., Choo, H. 2010; 141 (10): 7S–13S


    Comprehensive visualization and records of the craniofacial complex have been goals in orthodontic imaging. These tasks have been performed by means of plaster, photographs and radiographs. These approaches have evolved across time, and cone-beam computed tomography (CBCT) has emerged as a comprehensive imaging modality for orthodontics.The authors provide a practical guide for applying CBCT in orthodontics, with an emphasis on situations in which conventional imaging is limited. These situations include dental development, limits of tooth movement, airway assessment, craniofacial morphology and superimposition.Complexities of the craniofacial complex, dentition and airway present challenges in obtaining conventional images. CBCT has image-fidelity advantages over conventional imaging that can lead to improved visualization.CBCT is changing orthodontics with respect to clinically assessing patients and is evolving with respect to diagnosis, clinical techniques and outcomes.The clinical value proposition of CBCT is to describe craniofacial anatomy accurately and provide comprehensive information regarding anatomical relationships and individual patient findings for improved diagnosis, treatment planning and prognostication.

    View details for DOI 10.14219/jada.archive.2010.0361

    View details for Web of Science ID 000282847600002

    View details for PubMedID 20884934

  • Distalization of the mandibular dentition with mini-implants to correct a Class III malocclusion with a midline deviation AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS Chung, K., Kim, S., Choo, H., Kook, Y., Cope, J. B. 2010; 137 (1): 135–46


    This article describes the orthodontic treatment for a young woman, aged 23 years 5 months, with a Class III malocclusion and a deviated midline. Two orthodontic mini-implants (C-implants, CIMPLANT Company, Seoul, Korea) were placed in the interdental spaces between the mandibular second premolars and first molars. The treatment plan consisted of distalizing the mandibular dentition asymmetrically and creating space for en-masse retraction of the mandibular anterior teeth. C-implants were placed to provide anchorage for Class I intra-arch elastics. The head design of the C-implant minimizes gingival irritation during orthodontic treatment. Sliding jigs were applied buccally for distalization of the mandibular posterior teeth. The active treatment period was 18 months. Normal overbite and overjet were obtained, and facial balance was improved.

    View details for DOI 10.1016/j.ajodo.2007.06.023

    View details for Web of Science ID 000274393400021

    View details for PubMedID 20122441

  • Cone-beam computed tomography evaluation of orthodontic miniplate anchoring screws in the posterior maxilla. American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics Kim, G. T., Kim, S. H., Choi, Y. S., Park, Y. J., Chung, K. R., Suk, K. E., Choo, H., Huang, J. C. 2009; 136 (5): 628.e1-10; discussion 628-9


    The purposes of this study were to evaluate the actual postplacement positions of orthodontic miniplate anchoring screws (MPAS) and to determine the risk factors for their failure and iatrogenic effects on the intraoral structures.Three-dimensional cone-beam computed tomography images were generated to examine 31 orthodontic miniplates and their MPAS (diameter, 1.5 mm; length, 4 mm), which showed good clinical stability 6 months after placement in the posterior maxilla of 18 patients. The cone-beam computed tomography data were analyzed with analysis of variance (ANOVA) statistics to evaluate the difference of placement depth and vertical distance of the MPAS from the cementoenamel junction to the center of the screw. The Fisher exact test was used to determine differences in MPAS position, root proximity, and sinus penetration.The mean placement depth of the MPAS was 2.48 mm with no significant difference relative to their position. Twenty-six (of 74) MPAS were placed in the dentition area. Of these 26, 14 were placed in interdental spaces, and the other 12 followed the direction of the roots. Nine MPAS showed root proximity, and 7 MPAS had root penetration, all of which were placed in the central position of the miniplate. Thirty-nine MPAS penetrated the sinus, indicating a low interrelationship between placement depth and cortical bone thickness of the sinus.Miniplates were successfully retained by MPAS even with less-than-ideal placement. Root contact and proximity of MPAS seem to have minimal effects on the successful stabilization of miniplates. Pertinent guidelines should, however, be followed during MPAS placement to minimize the risk of damage to adjacent roots.

    View details for DOI 10.1016/j.ajodo.2009.02.023

    View details for PubMedID 19892272

  • Double-archwire mechanics using temporary anchorage devices to relocate ectopically impacted maxillary canines. World journal of orthodontics Kim, S. H., Choo, H., Hwang, Y. S., Chung, K. R. 2008; 9 (3): 255-66


    This case report introduces a novel double archwire mechanics concept using orthodontic mini-implants and a miniplate to relocate ectopically impacted maxillary canines in a 14-year-old female with a Class III subdivision left malocclusion. The objective of this orthodontic treatment was to salvage the maxillary lateral incisors so they could be used for conservative restorations upon completion of the orthodontic treatment and to guide the impacted maxillary canines to their correct anatomical positions. The authors report that an iatrogenic root resorption of the maxillary lateral incisors, which is caused by a direct root contact between teeth during the active relocating procedure, can be minimized by using double-archwire mechanics. The optimal overbite, overjet, and occlusal interdigitation were achieved after the orthodontic treatment. The facial balance was also improved. Active orthodontic treatment lasted 26 months, and the results remained stable for 13 months after the removal of orthodontic appliances. This report also shows that the gingival margins of the relocated maxillary canines can be established without postorthodontic periodontal procedures when effective orthodontic mechanics are utilized to retain the canines in the alveolar bone and minimize any contact of the roots with gingival tissues during active relocation of the impacted maxillary canines.

    View details for PubMedID 18834008

  • Anterior torque control using partial-osseointegrated mini-implants: biocreative therapy type II technique. World journal of orthodontics Chung, K. R., Kim, S. H., Kook, Y. A., Choo, H. 2008; 9 (2): 105-13


    To show the clinical application of surface-treated mini-implants (C-Implants) in managing an anterior torque control during en masse retraction of anterior dentition.Nickel-titanium archwire with reverse curve of Spee, which is directly engaged in the hole of C-Implants, and severe curve of Spee can be overlaid on anterior segmented archwires to generate anterior torque on the anterior dentition to resist lingual tipping during en masse retraction. This treatment mechanics is called the biocreative therapy type II technique. The characteristics and procedure of the type II technique for treating maximum anchorage using the C-Implants is shown with case reports of treated patients. The biomechanics and a comparison to the type I technique of this treatment are also described.The authors show the clinical application of type II technique during anterior retraction on various cases, possible indications, and simplicity of the mechanics.Biocreative therapy, which implements partial-osseointegrated mini-implants, presents a novel therapeutic approach in orthodontics. A technique of intrusion overlay archwires for anterior torque control also simplifies the design of orthodontic appliances while eliminating unwanted side effects, such as vertical changes on posterior anchorage teeth during en masse retraction.

    View details for PubMedID 18575304

  • Cone-beam computed tomography (CBCT) in clinical practice Pacific Coast Society of Orthodontists Bulletin Huang, J. C., Choo, H., Mah, J. K. 2008: 18-22