Yunn-Jy Chen

National Taiwan University | NTU · School of Dentistry

Background/purpose The impact of temporomandibular joint (TMJ) osseous destruction on bone mineral density (BMD) remains unclear due to controversial findings. Besides, no previous study has explored the relationship between idiopathic condylar resorption (ICR) and body composition. This study aimed to investigate the relationship between ICR and B...

Objectives This study aims to identify characteristics in image‐based computational fluid dynamics (CFD) in children with obstructive sleep apnea (OSA). Design Diagnostic study. Setting Hospital‐based cohort. Participants Children with symptoms suggestive of OSA were recruited and underwent polysomnography. Main outcome measures Three‐dimension...

Introduction Sonoelastography has been increasingly used for non-invasive evaluation of the mechanical features of human tissues. The interplay between orofacial pain and regional muscle activity appears clinically paramount, although only few imaging studies have investigated this association. Using shear wave sonoelastography (SWS), this study as...

Introduction Mandibular advancement device (MAD) is designed to pull the mandible and the tongue forward anteriorly to increase the cross-sectional airway dimension and thus possibly reduce airway obstructions during sleep. The effectiveness of a MAD may be affected by the pre-treatment OSA severity, BMI, and degree of changes in pharyngeal dimensi...

Introduction The association of mandibular advancement device (MAD) treatment response and polysomnographic phenotype in patients with obstructive sleep apnea (OSA) has not been fully elucidated. We hypothesized MAD response would be associated with two polysomnographic phenotypes, including sleep stage and positional dependency in treatment-naïve...

Purpose To explore the mandibular condylar movements in patients with temporomandibular joint (TMJ) disorders using kinematic magnetic resonance imaging (MRI). Methods We retrospectively recruited patients who were clinically diagnosed with internal derangement of the TMJ and referred to our center for MRI examination. The TMJ discs were categoriz...

Objective To assess the craniofacial morphology in children with sleep-disordered breathing (SDB) using nonradiation and readily accessible photogrammetry technique. Methods Included children aged 3–18 years with SDB-related symptoms from April 2019 to February 2020 in a tertiary center. All participants underwent craniofacial photogrammetry and o...

Importance: Early intervention using cone-beam computed tomography (CBCT) and adenotonsillectomy for children with obstructive sleep apnea (OSA) may prevent impaired growth, adverse cardiovascular consequences, learning deficits, and poor quality of life. Objective: To assess changes in CBCT airway measurements and polysomnography (PSG) parameters...

Knowledge of mandibular growth and development is essential for diagnosis of malformation and early interception. A previous method of quantifying mandibular growth using the distances between selected anatomical landmarks over the growth period does not provide a complete, quantitative description of the continuous growth patterns. The current stu...

Objective Both continuous positive airway pressure (CPAP) pressure and polysomnographic phenotypes have been associated with mandibular advancement device (MAD) treatment response, but the precise relationship has not been fully elucidated. We hypothesized that utilizing CPAP pressure would predict the MAD response in treatment-naïve patients with...

High-resolution ultrasound is preferred as the first-line imaging modality for evaluation of superficial soft tissues, such as the facial muscles. In contrast to magnetic resonance imaging and computed tomography, which require specifically designated planes (axial, coronal and sagittal) for imaging, the ultrasound transducer can be navigated based...

Introduction Mandibular advancement device (MAD) responder phenotype are not well understood in patients with obstructive sleep apnea (OSA). Recent studies have reported the association between MAD treatment response and polysomnographic phenotypes using positional and sleep stage dependency, but with inconsistent findings. Thus, the study aims to...

Few studies have explored the feasibility of shear-wave ultrasound elastography (SWUE) for evaluating the upper airways of patients with obstructive sleep apnea (OSA). This study aimed to establish a reliable SWUE protocol for evaluating tongue muscle elasticity and its feasibility and utility in differentiating patients with OSA. Inter-rater and i...

Background/purpose The nature of susceptibility to condylar resorption after orthognathic surgery can be different between skeletal Class II and Class III populations, which was addressed by few in the past. The aim of the present study was to use cone-beam computed tomographic (CBCT) images to investigate the displacement and morphological changes...

Purpose: This study aimed to investigate the relationship between polysomnographic (PSG) phenotype, sleep stage dependency and positional dependency, and mandibular advancement device (MAD) treatment response in patients with obstructive sleep apnea (OSA). Materials and Methods: This retrospective study recruited patients with OSA (apnea-hypopnea i...

Masticatory muscle thickness provides objective measurements of the oral motor function, which may change in patients with oral myofascial pain. In this study, we aimed to establish a reliable ultrasound (US) protocol for imaging the superficial and deep masticatory muscles and to identify the potential influencers of the measurements. Forty-eight...

Objectives To measure in vivo three-dimensional kinematics of the mandible and associated end-point trajectories and to quantify their relationships during temporomandibular joint activities using 3D fluoroscopy. Methods A novel fluoroscopy-based 3D measurement method was used to measure motions of the mandible and the associated end points (i.e....

Objective Cone‐beam computed tomography (CBCT) offers three‐dimensional structures in assessing upper airway of patients. This study aims to compare the cone‐beam computerized tomography scan measurements between children with obstructive sleep apnea (OSA) and primary snoring. Study Design Case–control study. Methods This prospective study was co...

Butyric acid as a histone deacetylase (HDAC) inhibitor is produced by a number of periodontal and root canal microorganisms (such as Porphyromonas, Fusobacterium, etc.). Butyric acid may affect the biological activities of periodontal/periapical cells such as osteoblasts, periodontal ligament cells, etc., and thus affect periodontal/periapical tiss...

Butyric acid as a histone deacetylase (HDAC) inhibitor was produced by a number of periodontal and root canal microorganisms (such as Porphyromonas, Fusobacterium etc.). Butyric acid may affect the biological activities of periodontal/periapical cells such as osteoblasts, periodontal ligament cells etc., and thus affect periodontal/periapical tissu...

Objective The aim of this study was to analyze morphological changes in the upper airways in patients with anterior open bite treated with temporary anchorage devices for intrusion of upper posterior teeth. Materials and Methods Twelve non‐obese (body mass index: <25) anterior open bite patients between the ages of 19 and 44 years (mean age: 22.83...

Obstructive sleep apnea (OSA), which is caused by obstructions of the upper airway, is a syndrome with rising prevalence. Mandibular advancement splints (MAS) are oral appliances for potential treatment of OSA. This work proposes a highly-sensitive pressure sensing array integrated with a system-on-chip (SoC) embedded in a MAS. The device aims to m...

[This corrects the article DOI: 10.1371/journal.pone.0187032.].

Introduction This study aimed to determine the effect of combining positive airway pressure (PAP) therapy and mandibular advancement device (MAD) in patients with severe obstructive sleep apnea (OSA) who were pressure intolerant for PAP and were unresponsive to MAD. Methods This retrospective study reviewed the medical records of severe OSA patien...

Pretreatment demographics and PPAP of 14 patients who underwent CT. (PDF)

Oxygen desaturation index (ODI) before and under treatment for the 14 patients who underwent CT. (PDF)

Comparison of pretreatment and PPAP of patients with MAD responder and non-responder. (PDF)

Apnea-hypopnea index (AHI) before and under treatment for the 14 patients who underwent CT. (PDF)

% total sleep time (TST) of SpO2 <90% before and under treatment for the 14 patients who underwent CT. (PDF)

Sleep apnea is a serious sleep disorder, and the most common type is obstructive sleep apnea (OSA). Untreated OSA will cause lots of potential health problems. Oral appliance therapy is an effective and popular approach for OSA treatment, but making a perfect fit for each patient is time-consuming and decreases its efficiency considerably. This pap...

A system integrating temperature, pressure and voice sensors is proposed for a smart oral appliance for use in diagnosing and alleviating obstructive sleep apnea (OSA). Using sealed bio-compatible packaging for intraoral use, this system is also capable of wireless charging and data transmission. This proposed design aims to enhance the effectivene...

Background Cephalometric radiography has been used for orthodontic and surgical treatment planning and assessment, and for quantifying mandibular growth. However, it remains unclear how head positioning errors and the level of examiner experience affect the reliability of such morphometric measurements. The current study aimed to bridge the gap by...

Dynamic magnetic resonance imaging (MRI) allows real-time characterization of upper airway collapse in sleeping subjects with obstructive sleep apnea (OSA). The aim of our study was to use sleep MRI to compare differences in upper airway collapse sites between BMI-matched subjects with mild OSA and severe OSA. This is a prospective, nested case–con...

Objectives: Using sleep MRI, we aimed to identify static craniofacial measurements and dynamic upper airway collapse patterns associated with severe obstructive sleep apnea (OSA) during natural sleep in age and BMI matched patients. Design: Nested case-control study. Setting: Sleep MRI images (3.0 Tesla scanner) and synchronized acoustic recor...

Obstructive sleep apnea syndrome (OSAS) is caused by multi-level upper airway obstruction. Anatomic changes at the sites of obstruction may modify the physical or acoustic properties of snores. The surgical success of OSA depends upon precise localization of obstructed levels. We present a case of OSAS who received simultaneous dynamic MRI and snor...

Background/purpose: The current study aimed to determine the intra- and inter-rater, and intersession reliability of the determination of the morphological parameters of the human mandible using cone-beam computed tomography (CBCT)-synthesized cephalometric radiographs. Materials and methods: CBCT data of 12 mandibles were obtained and used to gene...

Progressive narrowing of the upper airway increases airflow resistance and can produce snoring sounds and apnea/hypopnea events associated with sleep-disordered breathing due to airway collapse. Recent studies have shown that acoustic properties during snoring can be altered with anatomic changes at the site of obstruction. To evaluate the instanta...

Der frontal offene Biss ist wohl eine der besonderen Herausforderungen an eine kieferorthopädische Behandlung. Einige der Fälle können zum Teil mit Störungen im Bereich der Kiefergelenke in Verbindung gebracht werden. Solche Patienten zeigen häufig deutliche Attritionsfacetten auf den Okklusalflächen der Zähne und einen Verlust der Schneidekantenhö...

Background The current study aimed to compare the measurements of the mandible morphology using 3D cone beam computed tomography (CBCT) images with those using 2D CBCT-synthesized cephalograms; to quantify errors in measurements based on 2D synthesized cephalograms; and to clarify the effects such errors have on the description of the mandibular gr...

Background/Purpose Cone-beam computed tomography (CBCT) can provide valuable data for root canal systems of human teeth in vivo. This study used CBCT to evaluate the number of roots and canals of 300 mandibular first premolars in 150 northern Taiwanese patients. Methods The root canal systems of 300 mandibular first premolars in 150 northern Taiwa...

Purpose: This study aimed to develop and evaluate experimentally an implant-based registration method for measuring three-dimensional (3D) kinematics of the mandible and dental implants in the mandible based on dental cone beam computed tomography (CBCT), modified to include fluoroscopic function. Materials and methods: The proposed implant-base...

The purpose of this study was to measure the long-term growth of the mandible in miniature pigs using 3D Cone-Beam Computerized Tomography (CBCT). The mandibles of the pigs were scanned monthly over 12 months using CBCT and the 3D mandibular models were reconstructed from the data. Seventeen anatomical landmarks were identified and classified into...

Objectives Snore signals are produced by soft tissue vibration in the upper airway (UA). To date, there is no gold standard to localize UA narrowing sites in patients with obstructive sleep apnea syndrome (OSAS). In this study, we use a “vocal tract model” to investigate the association between snore acoustic characteristics and UA collapse. Dynami...

To explore the relationship between general joint hypermobility (GJH) and displacement of the temporomandibular joint (TMJ) disc as evident from magnetic resonance imaging (MRI). Fifth finger extension, thumb apposition, elbow extension, knee extension, trunk flexion, and ankle dorsiflexion were measured in 66 young female patients with MRI-evident...

Objective: OSA is caused by soft tissue collapse of the upper airway; treatment strategies can be determined depending on accurately localizing the obstruction sites. Acoustic analysis of snoring might provide a valuable way to localize the obstruction, if the association between the acoustics and the dynamics of the upper airway during OSA can be...

Background/purpose: The measurement of mandibular kinematics is critical for studying the function of the temporomandibular joint (TMJ) and for relevant clinical applications. However, none of the existing methods allows the measurement of three-dimensional (3D) in vivo motion of the joint during dynamic functional movements without artifactual int...

Accurate measurement of the three-dimensional (3D) kinematics of the temporomandibular joint (TMJ) in vivo is essential for relevant clinical applications. Existing measurement methods are either of limited accuracy, difficult to implement, or interfere with TMJ movement. This study develops a marker-cluster registration method (MCRM) for the measu...

Background/purpose: Skin marker-based systems are used to accurately measure the three-dimensional motion of the temporomandibular joint. Since skin markers move relative to the underlying bone during jaw movements, the measured temporomandibular joint kinematics is subject to soft-tissue artifacts. A complete evaluation of soft-tissue artifacts fo...

This study investigated whether the presence of tooth wear in young adults can help to discriminate patients with sleep bruxism (SB) from control subjects. The tooth wear clinical scores and frequency of sleep masseter electromyographic activity of 130 subjects (26.6 +/- 0.5 years) were compared in this case-control study. Tooth wear scores (collec...

Obstructive sleep apnea (OSA) syndrome is a common sleeping disorder problem. The diagnosis depends on features of patient’s clinical symptoms and polysomnographic examination. Among several treatment modalities in OSA patients, oral appliance is a simple, effective and popular treatment option. Oral appliances have been clearly shown to improve ma...

To assess the effects of epigallocatechin-3-gallate (EGCG) on oncostatin M (OSM)-induced CCL2 synthesis and the associated signaling pathways in human osteoblastic cells. The therapeutic effect of EGCG on collagen-induced arthritis (CIA) in rats was also studied. CCL2 and c-Fos messenger RNA expression was analyzed by Northern blotting. The modulat...

To analyze the bone mineral density (BMD) in a group of young female patients with a disc displacement in at least 1 temporomandibular joint (TMJ) as well as in a group of age-matched young females with a normal condyle-disc relationship. Fifty-six young female patients with anterior disc displacement based on magnetic resonance imaging (MRI) and 4...

Acquired anterior open bites were reported as the consequence of condylar collapse, which was associated with inflammatory TMJ disorders. However, we have seen such malocclusion patients whose condylar changes seemed to be related to TMJ degeneration associated with internal derangement. The aims of this study were to review the clinical history an...

To compare the results of 3 methods of recognizing internal derangements with a clicking sound on condylar movement: 2 function-based methods (clinical examination and condylar movement recording) and 1 anatomy-based method (magnetic resonance imaging [MRI]). For the recognition of an anterior or posterior disc displacement with reduction and of hy...

Temporomandibular joint (TMJ) discs displaced simultaneously, dorsoventrally, and mediolaterally are assumed to be rotated. However, a pilot study performed with individualized oblique-axial scans on supposedly rotated discs did not show disc rotation consistently. The aim of this study was the quantitative evaluation of disc rotation on a larger s...

A new individualized oblique-axial orientation of magnetic resonance imaging scans of the temporomandibular joint (TMJ), corrected to be perpendicular to the tangent of the posterior slope of the articular eminence, has been proposed to improve the representation of the disc. The aim of this study was to evaluate the quality of the images obtained...

Echo planar imaging (EPI) is an ultrafast magnetic resonance imaging (MRI) technique that can scan a single frame in less than a second. The aim of this study was to use the EPI technique to develop a new dynamic MRI protocol for the temporomandibular joint (TMJ). Basic fast-field echo and EPI pulse sequences were used for dynamic studies of the TM...

Objectives: The severity of obstructive sleep apnea (OSA), namely apnea/hypopnea index (AHI), is widely used as a reference in selecting the treatment options, namely using oral appliances (OA) in treating mild to moderate OSA patients. The aim of this study was to evaluate the treatment outcomes of OSA by using a mandible advancing OA with respect...