Orthodontic correction of acquired open bite with TMJ degeneration: A retrospective study of outcomes and stability.

BACKGROUND/PURPOSE: Newly developed temporary anchorage devices (TADs) serve a strong orthodontic anchorage to intrude molars for correction of anterior open bite (AOB). We measured cephalometric changes in skeletal open bite patients which developed subsequently to temporomandibular joint disorders with bilateral point contacts at terminal molars. METHODS: We retrospectively recruited 32 patients who had been treated their TMD before orthodontic correction (overbite: -3.14 ± 1.86 mm). Partial orthodontic appliances were used to intrude posterior teeth using TADs until positive OB obtained (T1). Full fixed appliances were then used to achieve proper overjet and overbite (T2). We collected lateral cephalograms before (T0), during (T1) and after (T2) treatment, and at follow-ups (T3). Using ANOVA, we analyzed the differences among these time points to determine treatment changes and stability of orthodontic results. RESULTS: In this group predominantly comprising young adult women, orthodontic treatment with TADs significantly reduced upper posterior dental heights (T2-T0:-1.84 ± 0.66 mm) and facilitated the retraction and uprighting upper incisors (T2-T0: -9.92 ± 1.72°), to achieve appropriate OJ (T2-T0: -3.21 ± 0.49 mm) and OB (T2-T0: 4.10 ± 0.28 mm) with p < 0.05. Except upper posterior dental height, most of cephalometric changes including OJ, OB, and upper incisal axis remained significant at follow-ups with retention time of 3.7 ± 2.6 years. Only three out of 30 patients experienced small amount of open bite at T3. CONCLUSION: Orthodontic correction of OJ remained relatively stable among 90 % of patients with TMJ degeneration by intrusion via TADs. This modern but conservative orthodontic approach can improve occlusal functions in skeletal open bites.

Computational fluid dynamics study in children with obstructive sleep apnea.

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-dimensional models of computational fluid dynamics were derived from cone-beam computed tomography. RESULTS: A total of 68 children participated in the study (44 boys; mean age: 7.8 years), including 34 participants having moderate-to-severe OSA (apnea-hypopnea index [AHI] greater than 5 events/h), and 34 age, gender, and body mass index percentile matched participants having primary snoring (AHI less than 1). Children with moderate-to-severe OSA had a significantly higher total airway pressure (166.3 vs. 39.1 Pa, p = .009), total airway resistance (9851 vs. 2060 Newton-metre, p = .004) and velocity at a minimal cross-sectional area (65.7 vs. 8.8 metre per second, p = .017) than those with primary snoring. The optimal cut-off points for moderate-to-severe OSA were 46.2 Pa in the total airway pressure (area under the curve [AUC] = 73.2%), 2373 Newton-metre in the total airway resistance (AUC = 72.5%) and 12.6 metres per second in the velocity at a minimal cross-sectional area (AUC = 70.5%). The conditional logistic regression model revealed that total airway pressure, total airway resistance and velocity at minimal cross-sectional area were significantly associated with an increased risk of moderate-to-severe OSA. CONCLUSIONS: This study demonstrates that CFD could be a useful tool for evaluating upper airway patency in children with OSA.

Assessing thickness and stiffness of superficial/deep masticatory muscles in orofacial pain: an ultrasound and shear wave elastography study.

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 ascertained whether orofacial pain induced alterations in the stiffness of superficial and deep masticatory muscles. METHODS: All participants were systematically evaluated for oral/facial-related conditions, including the area and intensity of pain. SWS was applied to measure the stiffness of the bilateral masseter, temporalis, and lateral pterygoid muscles. The association between orofacial pain and muscle stiffness/thickness was investigated using a generalized estimating equation for adjusting the influence of age, sex, laterality, and body mass index on muscle thickness/stiffness. RESULTS: A total of 98 participants were included in the present study: 48 asymptomatic controls, 13 patients with unilateral pain, and 37 patients with bilateral orofacial pain. The reliability, quantified by the intraclass correlation coefficient for muscle stiffness measurement, ranged from 0.745 to 0.893. Orofacial pain at the individual muscle level was significantly associated with masseter muscle stiffness. A trend of increased stiffness (p = 0.06) was also observed in relation to the painful side of the temporalis muscle. No significant correlation was identified between the numeric rating scales for pain and stiffness measurements. CONCLUSIONS: SWS provides reliable stiffness measurements for the superficial and deep masticatory muscles. The ipsilateral masseter and temporalis muscles might be stiffer than those on the side without orofacial pain. Future studies using the present sonoelasotography protocol can be designed to investigate the stiffness changes in the target muscles after interventions.

Shear wave sonoelastography (SWS) can reliably assess the stiffness of masticatory muscles.Orofacial pain, particularly affecting the ipsilateral masseter muscles, exhibited increased stiffness, with a similar trend observed in the temporalis muscle as revealed by SWS. However, the stiffness of the lateral pterygoid muscle appeared to remain unaffected.These findings establish a foundational framework for the objective and quantitative assessment of orofacial pain and indicate the potential utility of SWS as a tool for evaluating treatment outcomes.

Kinematic magnetic resonance imaging for the evaluation of active motion of the mandibular condyle in patients with temporomandibular joint disorders.

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 categorized into normal disc (ND), anteriorly displaced disc (ADD), and disc with destruction (DD) groups using static images obtained in the closed-mouth view. The difference between the "open-mouth" and "closed-mouth" views on kinematic MRI was used to calculate the condylar translation and rotation. Two radiologists consensually performed the image readings and measurements. One-way analysis of variance and chi-squared test were used to compare the variables in the three groups. Pearson's correlation and general linear models were used to evaluate the correlation and differences between condylar translation and rotation in the three groups. RESULTS: This study included 98 TMJs from 54 patients. Twenty-six, 49, and 23 TMJs were classified as ND, ADD, and DD, respectively. Condylar rotation and translation demonstrated a significant correlation in all TMJs examined (r = 0.635, p < 0.001), with similar coefficients for all groups. The mean condylar translation in the ND group was greater than that in the ADD and DD groups (ND versus ADD: p = 0.003; ND versus DD: p = 0.002). However, the change in condylar rotation was not affected by the disc status (ND as reference; DD∗condylar translation: coefficient = 0.341, p = 0.332; ADD∗condylar translation: coefficient = -0.100, p = 0.696). CONCLUSION: Kinematic MRI studies revealed that TMJ condylar translation was correlated with its rotation for all disc statuses.

Measurements of craniofacial morphology using photogrammetry in children with sleep-disordered breathing.

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 overnight polysomnography (PSG). Participants were stratified into 2 groups (obstructive sleep apnea [OSA] group: apnea-hypopnea index [AHI] ≥ 1 and non-OSA group: AHI <1). Craniofacial photogrammetry was performed to derive variables of craniofacial features in standardized frontal and profile views. The 2 groups were propensity score matched based on age, sex, and body mass index (BMI) percentiles. Associations between craniofacial feature variables and OSA (AHI ≥1) likelihood were examined using logistic regression test. intraclass correlation coefficient (ICC) was used to evaluate the intrarater and interrater reliability. RESULTS: In total, 58 children were enrolled for the analysis after matching. All 3 variables representing the mandibular plane angle in the profile view were increased in the OSA group (mego-tn: 34.85 ± 5.99 vs 31.65 ± 5.96°, odds ratio [OR]: 1.10, 95% CI:1.02 to 1.18, P = .01; tn-gogn: 28.65 ± 6.38 vs 25.91 ± 5.38°, OR: 1.08, 95% CI:1.02 to 1.15, P = .012; and gome-tsup: 26.71 ± 6.13 vs 22.20 ± 5.89°, OR: 1.13, 95% CI:1.04 to 1.23, P = .003). CONCLUSIONS: Craniofacial photogrammetry revealed increased mandibular inclination in children with OSA. A steep mandibular plane with craniofacial photogrammetry is considered a potential predictor of pediatric OSA. Further investigation with a large sample size is required to clarify the validity of photogrammetry in evaluating pediatric OSA.

A Non-Linear Osteometric Modeling Method for Three-Dimensional Mandibular Morphological Changes During Growth: One-Year Monitoring of Miniature Pigs Using Cone-Beam Computed Tomography.

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 study aimed to bridge the gap by measuring the 3D continuous growth of the mandible in miniature pigs using cone-beam computerized tomography (CBCT). The mandibles of the pigs were CBCT-scanned monthly over 12 months, and the 3D mandibular models were reconstructed. A new non-linear, time-dependent osteometric modeling approach was developed to register two consecutive mandible models by searching for the corresponding points with the highest likelihood of matching the anatomical and morphological features so that the morphological changes patterns for each month could be described using color maps on the models. The morphological changes of the mandible were found to decrease anteriorly, with the condyle region and the posterior part of the ramus growing faster than the rest of the mandible. The condyle region showed the fastest growth rate and the posterior ramus the second during the growth period, while the middle and anterior corpus regions showed the slowest growth rates. In conclusion, the current results revealed the non-linear patterns and rates of morphological changes in different growth regions and the whole mandible. The new approach may also be useful for future studies on the growth of the mandible in other animals.

Changes in Cone-Beam Computed Tomography Pediatric Airway Measurements After Adenotonsillectomy in Patients With OSA.

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 that occur after adenotonsillectomy in children with OSA and to determine whether CBCT changes are correlated with apnea-hypopnea index (AHI) reduction. Design, Setting, and Participants: This prospective cohort study was conducted at a tertiary medical center from 2013 to 2016. Children aged 7 to 13 years with PSG-confirmed OSA (ie, AHI ≥1) were recruited. Data analysis was performed from March to July 2021. Exposures: All participants underwent CBCT and PSG before and after adenotonsillectomy. Main Outcomes and Measures: Changes in PSG and CBCT parameters after adenotonsillectomy were analyzed. Results: A total of 49 children (mean [SD] age, 9.5 [1.8] years; 34 boys [69.4%]) were recruited. Eighteen participants (36.7%) had obesity. After adenotonsillectomy, AHI significantly decreased from 11.4 to 1.2 events per hour (mean difference, -10.24 events per hour; 95% CI, -13.84 to -6.64 events per hour). The following CBCT parameters significantly increased: total airway volume (from 11 265 to 15 161 mm3; mean difference, 3896.6 mm3; 95% CI, 2788.0 to 5005.2 mm3), nasopharyngeal volume (from 2366 to 3826 mm3; mean difference, 1459.7 mm3; 95% CI, 1122.9 to 1796.5 mm3), minimal nasopharyngeal airway area (from 128 to 191 mm2; mean difference, 63.1 mm2; 95% CI, 47.4 to 78.8 mm2), mean nasopharyngeal airway area (from 144 to 231 mm2; mean difference, 86.8 mm2; 95% CI, 67.0 to 106.5 mm2), oropharyngeal volume (from 8898 to 11 335 mm3; mean difference, 2436.9 mm3; 95% CI, 1477.0 to 3396.8 mm3), minimal oropharyngeal airway area (from 82 to 158 mm2; mean difference, 76.2 mm2; 95% CI, 57.0 to 95.4 mm2), and mean oropharyngeal airway area (from 182 to 234 mm2; mean difference, 52.5 mm2; 95% CI, 33.6 to 71.4 mm2). Among all parameters, only body mass index percentile showed large effect size between the group with residual OSA (postoperative AHI ≥1) and the group with resolved disease, with the residual OSA group having a higher body mass index percentile (87.8 vs 61.4; mean difference, 26.33; 95% CI, 10.00 to 42.66). A quantile regression model revealed that total airway volume and minimal oropharyngeal airway area were significantly correlated with reductions in AHI. Conclusions and Relevance: These findings suggest that in children undergoing adenotonsillectomy, improvements in total airway volume and oropharyngeal minimal airway area were correlated with reduction of AHI. Future studies are needed to assess whether CBCT has a role in the evaluation of children with OSA who are being considered for adenotonsillectomy.

Prediction of Mandibular Advancement Device Response Using CPAP Pressure in Different Polysomnographic Phenotypes.

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 moderate-severe obstructive sleep apnea (OSA), and the MAD response would be associated with two polysomnographic phenotypes, including sleep stage dependency and positional dependency. Methods: OSA treatment-naïve patients with an apnea-hypopnea index (AHI) ≥15/h who declined CPAP treatment and received MAD treatment for 3-6 months were enrolled. The MAD treatment response was defined as 1) residual AHI under MAD (AHIMAD) <5/h and 2) AHIMAD <10/h. Logistic regression was applied to identify the association between CPAP pressure and MAD treatment responders. The predictability of the MAD responder status utilizing CPAP pressure was assessed with the area under the receiver operating characteristic (AUROC). Results: A total of 128 enrolled patients (AHI ≥30/h in 74.2%) were recruited, of whom 119 patients and 80 patients were included for analysis of sleep stage and positional dependency, respectively. REM-predominant OSA had lower AHI than stage-independent OSA, while the supine-predominant phenotype had lower anthropometrics than the nonpositional-dependent phenotype. The response rates for AHIMAD <5/h and AHIMAD <10/h were 25.8% and 48.4%, respectively. Lower anthropometrics, baseline AHI, and supine predominance were associated with the responder status, while CPAP pressure was an independent predictor. The AUROCs for the prediction of AHIMAD <5/h and AHIMAD <10/h responders were 0.635 and 0.664, respectively. Utilizing a CPAP level >14 cmH2O as the cutoff to predict criterion 1 and 2 nonresponders, the sensitivity was 93.9% and 95.2%, respectively. Conclusion: In treatment-naïve patients with moderate-severe OSA, the supine-predominant phenotype and lower CPAP pressure were associated with the MAD response, while the sleep stage dependency phenotype was not. Utilization of a CPAP level >14 cmH2O could be a sensitive measure to identify nonresponders.

Ultrasound Imaging of the Facial Muscles and Relevance with Botulinum Toxin Injections: A Pictorial Essay and Narrative Review.

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 on the alignment of facial muscles. Botulinum toxin injections are widely used in facial cosmetic procedures in recent times. Ultrasonography is recognized as a useful tool for pre-procedure localization of target muscles. In this pictorial review, we discuss the detailed sonoanatomy of facial muscles and their clinical relevance, particularly with regard to botulinum toxin injections. Furthermore, we have summarized the findings of clinical studies that report ultrasonographic imaging of facial muscles.

Differences of condylar changes after orthognathic surgery among Class II and Class III patients.

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 of temporomandibular joints (TMJs) in patients received orthodontic treatment combined with orthognathic surgery. METHODS: Both Class III (n = 34) and Class II (n = 17) patients were compared through overall and regional superimpositions of the initial and posttreatment CBCTs. Two-sample t-test was used to identify significance between group differences. Pearson's correlation coefficient was used to address changes of TMJ and the amount of setback or advancement. RESULTS: The axial ramal angle increased significantly in Class III group and decreased in Class II groups after orthognathic surgery (p < FDR_p). For condylar dimensions, significant widths and lengths reductions were noted only in Class II group. However, no significant difference was found after comparing subgroup differences according to one-jaw and two-jaw options, nor any significant correlation found between the condylar changes and the amount of surgical movements. CONCLUSION: The nature of condylar susceptibility could result more from different skeletal patterns than the amount of surgical movements. However, the direction of mandibular surgery may contribute to different changes of condylar angle in axial section.

Reliability of Sonoelastography Measurement of Tongue Muscles and Its Application on Obstructive Sleep Apnea.

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 intra-rater reliability of SWUE measurements were tested using the intraclass correlation coefficients. Submental ultrasound was used to measure tongue thickness and stiffness. Association between the ultrasound measurements and presence of OSA was analyzed using multivariate logistic regression. One-way analysis of variance was used to examine if the values of the ultrasound parameters varied among patients with different severities of OSA. Overall, 37 healthy subjects and 32 patients with OSA were recruited. The intraclass correlation coefficients of intra- and inter-rater reliability for SWUE for tongue stiffness ranged from 0.84 to 0.90. After adjusting for age, sex, neck circumference, and body mass index, the risk for OSA was positively associated with tongue thickness [odds ratio 1.16 (95% confidence interval 1.01-1.32)] and negatively associated with coronal imaging of tongue muscle stiffness [odds ratio 0.72 (95% confidence interval 0.54-0.95)]. There were no significant differences in tongue stiffness among OSA patients with varying disease severity. SWUE provided a reliable evaluation of tongue muscle stiffness, which appeared to be softer in patients with OSA. Future longitudinal studies are necessary to investigate the relationship between tongue softening and OSA, as well as response to treatment.

In vivo three-dimensional mandibular kinematics and functional point trajectories during temporomandibular activities using 3d fluoroscopy.

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. incisors and lateral poles of both condyles) during open close, lateral gliding and protrusion-retraction movements in healthy young individuals. The contributions of each of the rotational and translational components of the mandible to the end-point trajectories were quantified through experiment-based computer simulations. RESULTS: The mandibular rotation was found to account for 91% of the maximal mouth-opening-capacity and 73% of the maximal lateral incisor movement, while the condylar translation contributed to 99% of the anterior protrusion distance. Incisor trajectories were nearly vertical within the first 60% of the maximal opening during the open-close movement. CONCLUSIONS: Similar condylar downward rotation paths but with bilaterally asymmetrical ranges were used to perform basic mandibular movements of different targeted TI trajectories in three dimensions, that is, open-close, lateral-gliding and protrusion-retraction. Mandibular rotations contributed to the majority of the principal displacement components of the incisor, that is, vertical during open-close and towards the working-side-during lateral-gliding, while mandibular translation contributed mainly to the forward movement of the incisor during protrusion-retraction. Owing to the anatomical constraints, the freedom of mandibular translation is limited and mainly in the anteroposterior direction, which is considered helpful for the control and stability of the TMJ during oral activities.

Evaluation of Upper Airway in Children with Obstructive Sleep Apnea Using Cone-Beam Computed Tomography.

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 conducted in a tertiary referral center. Thirty-six children with moderate-to-severe OSA (with apnea-hypopnea index [AHI] > 5 events/hour) and 36 age-, gender-, and obesity-matched children with primary snoring (AHI <1) were enrolled. The measurements in CBCT parameters were compared between children with moderate-to-severe OSA and primary snorers by conditional logistic regression model. RESULTS: A total of 72 children (mean age, 7.9 ± 2.8 years; 64% male) were included. Children with moderate-to-severe OSA had a significantly smaller nasopharyngeal (2900 ± 1400 vs. 3800 ± 1800 mm3 , P = .017) and oropharyngeal airway volume (5600 ± 2700 vs. 7400 ± 4000 mm3 , P = .026) than those with primary snoring. Children with moderate-to-severe OSA, as compared to primary snorers, also had a significantly smaller minimal airway area in nasopharynx (77.4 ± 37.7 vs. 107.7 ± 52.0 mm2 , P = .006) and oropharynx (66.6 ± 61.9 vs. 101.6 ± 65.8 mm2 , P = .023). Moreover, the airway length was not significantly different between children with moderate-to-severe OSA and primary snoring. CONCLUSIONS: The three-dimensional CBCT airway analysis could be used as a useful tool to evaluate upper airway in children with OSA. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:680-685, 2021.

Ultrasound measurements of superficial and deep masticatory muscles in various postures: reliability and influencers.

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 healthy participants without orofacial pain were enrolled. The intra-and inter-rater reliabilities of US measurements for masseter, temporalis, and lateral pterygoid muscles were assessed. Intraclass correlation coefficients for all muscles were greater than 0.6. The generalised estimating equation was used to analyse the impact of age, gender, laterality, and body mass index on the measurements, whereby age and body mass index were likely to be associated with an increase in masticatory muscle thickness. The thickness tended to be lesser in females. Laterality seemed to exert minimal influence on masticatory muscle thickness. Our study shows acceptable reliability of US in the evaluation of superficial and deep masticatory muscle thickness. Future studies are warranted to validate the usefulness of US imaging in patients with oral myofascial pain syndrome.

Butyrate Stimulates Histone H3 Acetylation, 8-Isoprostane Production, RANKL Expression, and Regulated Osteoprotegerin Expression/Secretion in MG-63 Osteoblastic Cells.

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 tissue destruction and healing. The purposes of this study were to study the toxic effects of butyrate on the matrix and mineralization marker expression in MG-63 osteoblasts. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cellular apoptosis and necrosis were analyzed by propidium iodide/annexin V flow cytometry. The protein and mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) were analyzed by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). OPG, soluble RANKL (sRANKL), 8-isoprostane, pro-collagen I, matrix metalloproteinase-2 (MMP-2), osteonectin (SPARC), osteocalcin and osteopontin (OPN) secretion into culture medium were measured by enzyme-linked immunosorbant assay. Alkaline phosphatase (ALP) activity was checked by ALP staining. Histone H3 acetylation levels were evaluated by immunofluorescent staining (IF) and Western blot. We found that butyrate activated the histone H3 acetylation of MG-63 cells. Exposure of MG-63 cells to butyrate partly decreased cell viability with no marked increase in apoptosis and necrosis. Twenty-four hours of exposure to butyrate stimulated RANKL protein expression, whereas it inhibited OPG protein expression. Butyrate also inhibited the secretion of OPG in MG-63 cells, whereas the sRANKL level was below the detection limit. However, 3 days of exposure to butyrate (1 to 8 mM) or other HDAC inhibitors such as phenylbutyrate, valproic acid and trichostatin stimulated OPG secretion. Butyrate stimulated 8-isoprostane, MMP-2 and OPN secretion, but not procollagen I, or osteocalcin in MG-63 cells. Exposure to butyrate (2⁻4 mM) for 3 days markedly stimulated osteonectin secretion and ALP activity. In conclusion, higher concentrations of butyric acid generated by periodontal and root canal microorganisms may potentially induce bone destruction and impair bone repair by the alteration of OPG/RANKL expression/secretion, 8-isoprostane, MMP-2 and OPN secretion, and affect cell viability. However, lower concentrations of butyrate (1⁻4 mM) may stimulate ALP, osteonectin and OPG. These effects are possibly related to increased histone acetylation. These events are important in the pathogenesis and repair of periodontal and periapical destruction.

Tongue Pressure Sensing Array Integrated with a System-on-Chip Embedded in a Mandibular Advancement Splint.

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 measure tongue pressure distribution in order to determine the efficacy of the MAS for treating OSA. The flexible sensing array consists of an interdigital electrode pair array assembled with conductive polymer films and an SoC capable of retrieving/storing data during sleep, and transmitting data for analysis after sleep monitoring. The surfaces of the conductive polymer films were patterned with microdomed structures, which effectively increased the sensitivity and reduced the pressure sensing response time. The measured results also show that the crosstalk effect between the sensing elements of the array was negligible. The sensitivity of the sensing array changed minimally after the device was submerged in water for up to 100 h.

Airway increase after open bite closure with temporary anchorage devices for intrusion of the upper posteriors: Evidence from 2D cephalometric measurements and 3D magnetic resonance imaging.

OBJECTIVE: The aim of this study was to analyse 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 nonobese (body mass index: <25) anterior open bite patients between the ages of 19 and 44 years (mean age: 22.83 ± 8.19 years) were recruited for this study. Cephalometric radiographs and magnetic resonance imaging (MRI) scans before and after anterior bite closure without bracketing on anterior teeth were used to measure the upper airway, which was divided into retropalatal and retroglossal regions. RESULTS: The mandibular plane angle and lower facial height were significantly reduced by intrusion of the upper posteriors and autorotation of the mandible. The retroglossal airway width (AW2) and retroglossal area (RG area) measured on cephalometric radiographs both increased significantly after treatment. Retroglossal volume increased and the retroglossal width/length ratio decreased significantly in MRI analysis. All other measurements were not significantly changed. However, no statistically significant correlations were observed between all measurements in 2D and 3D images, with the exception of the AW2 linear measurement in 2D images correlating with the AP length in MRI axial view images (r = 0.56, P = 0.0430). CONCLUSION: Counterclockwise rotation of the mandible after anterior open bite closed using orthodontic treatment changed the airway morphology. Retroglossal volume significantly increased and the airway shape became less elliptical after bite closure.

Correction: Combining MAD and CPAP as an effective strategy for treating patients with severe sleep apnea intolerant to high-pressure PAP and unresponsive to MAD.

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

Ultrasound Guided Injection for Medial and Lateral Pterygoid Muscles: A Novel Treatment for Orofacial Pain.

.

Combining MAD and CPAP as an effective strategy for treating patients with severe sleep apnea intolerant to high-pressure PAP and unresponsive to MAD.

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 patients with apnea-hypopnea index (AHI) ≥ 30/hr who were diagnosed between October 1, 2008 and June 30, 2014. Patients were initially treated with 2 weeks of PAP, and those who were intolerant to high-pressure PAP (≥15 cm H2O) were switched to 12 weeks of MAD, which is a monobloc designed at 75% of maximum protrusion. Patients who had high residual AHI (≥15/hr) on MAD underwent 12 weeks of combination therapy (CT) with MAD and CPAP and were enrolled in the present study. Enrolled subjects who completed the 12-week CT were followed-up until June 30, 2016. RESULTS: A total of 14 male patients were included. All three treatments effectively reduced AHI, oxygen desaturation index (ODI), and total sleep time with SpO2 <90% (% TST-SpO2<90%) compared to pretreatment values. The residual AHI and ODI on CT was lower than that on MAD or PAP. The residual % TST-SpO2<90% was lower than that on MAD and similar to that on PAP. The therapeutic pressure on CT was on average 9.2 cm H2O lower than that on PAP. For the 11 patients who completed CT, only CT reduced ESS compared to pretreatment value. No treatment had significant impact on % slow wave sleep or overnight change of blood pressure. For patients who completed CT, the average usage was 5.9±1.7 hr/night at 12th week and 6.4±1.5 hr/night at a median follow-up of 36.5-months. CONCLUSIONS: Combining MAD and CPAP showed additive effects on reducing AHI and ODI, and lowered the therapeutic pressures.