• Phonetics and Speech Sciences
• /
• v.11 no.1
• /
• pp.1-8
• /
• 2019

Formant trajectories reflect the continuous variation of speakers' articulatory movements over time. This study examined formant trajectories of English vowels produced by ninety-three American men and women; the values were normalized using the scale function in R and compared using generalized additive mixed models (GAMMs). Praat was used to read the sound data of Hillenbrand et al. (1995). A formant analysis script was prepared, and six formant values at the corresponding time points within each vowel segment were collected. The results indicate that women yielded proportionately higher formant values than men. The standard deviations of each group showed similar patterns at the first formant (F1) and the second formant (F2) axes and at the measurement points. R was used to scale the first two formant data sets of men and women separately. GAMMs of all the scaled formant data produced various patterns of deviation along the measurement points. Generally, more group difference exists in F1 than in F2. Also, women's trajectories appear more dynamic along the vertical and horizontal axes than those of men. The trajectories are related acoustically to F1 and F2 and anatomically to jaw opening and tongue position. We conclude that scaling and nonlinear testing are useful tools for pinpointing differences between speaker group's formant trajectories. This research could be useful as a foundation for future studies comparing curvilinear data sets.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.50 no.3
• /
• pp.166-169
• /
• 2024

Ankylosis of the temporomandibular joint (TMJ) is a condition in which the mandibular condyle fuses with the mandibular fossa through fibrous or bone tissue. It is a debilitating pathology that interferes with chewing, speaking, and oral hygiene. Currently, alloplastic reconstruction is considered the gold standard for treating severely compromised TMJs, such as in ankylosis. The article describes a patient with a history of facial trauma, with bilateral ankylosis of the TMJs, inability to open his mouth, and poor dental condition. Due to a long period of immobilization of approximately 40 years, the initial treatment plan was to remove the ankylosis bilaterally and install customized PMMA (polymethylmethacrylate) spacers. The patient gained mouth opening and improved chewing quality with one year of customized spacer use prior to definitive alloplastic replacement with stock-type TMJ prostheses. Customized joint spacers are a provisional treatment option when definitive alloplastic reconstruction is not indicated. Spacers provide the patient with progressive jaw function and mobility gains.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.17 no.2
• /
• pp.75-84
• /
• 2001

The purpose of this study is to to analyze the mechanical stress on articular disk of the dentated skull with the condition of unilateral posterior molar missing. For this study, the three dimensional finite element model of human skull scanned by means of computed tomography. (G.E. 8800 Quick, USA) was constructed. The finite element model of jaws is composed of 98,394 elements and 38,321 nodes, and it consists of articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. Boundary condition included rigid restraints at the first molar and endosteal cortical surfaces of the insertion points of temporal bone. The data derived from Nelson's study were used for the loading conditions of mandible during clenchings and for maxilla, new loading and constraint conditions were applied. A clenching task during intercuspal position was modeled to the three dimensional finite element model. The stress level and displacement of articualr disc on the model with unilateral posterior molar missing under bilateral clenching task can be analyzed. During bilateral clenchings, the compressive stress level and diplacement of the articular disk on the side of unilateral posterior molar missing is greater than that on the case with full dentition, whereas a higher stress was found on the disk on the balancing side of the full dentition. Although this kind of study is not enough to explain the role of occlusion as an etiologic factor of TMD, there may be a possibiliy that the condition of posterior molar missings may contribute in part to the TMJ biomechanics.

• The Korean Journal of Pain
• /
• v.30 no.2
• /
• pp.86-92
• /
• 2017

Osteoblasts, originating from mesenchymal cells, make the receptor activator of the nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in order to control differentiation of activated osteoclasts, originating from hematopoietic stem cells. When the RANKL binds to the RANK of the pre-osteoclasts or mature osteoclasts, bone resorption increases. On the contrary, when OPG binds to the RANK, bone resorption decreases. Denosumab (AMG 162), like OPG (a decoy receptor), binds to the RANKL, and reduces binding between the RANK and the RANKL resulting in inhibition of osteoclastogenesis and reduction of bone resorption. Bisphosphonates (BPs), which bind to the bone mineral and occupy the site of resorption performed by activated osteoclasts, are still the drugs of choice to prevent and treat osteoporosis. The merits of denosumab are reversibility targeting the RANKL, lack of adverse gastrointestinal events, improved adherence due to convenient biannual subcutaneous administration, and potential use with impaired renal function. The known adverse reactions are musculoskeletal pain, increased infections with adverse dermatologic reactions, osteonecrosis of the jaw, hypersensitivity reaction, and hypocalcemia. Treatment with 60 mg of denosumab reduces the bone resorption marker, serum type 1 C-telopeptide, by 3 days, with maximum reduction occurring by 1 month. The mean time to maximum denosumab concentration is 10 days with a mean half-life of 25.4 days. In conclusion, the convenient biannual subcutaneous administration of 60 mg of denosumab can be considered as a first-line treatment for osteoporosis in cases of low compliance with BPs due to gastrointestinal trouble and impaired renal function.

• Journal of Oral Medicine and Pain
• /
• v.18 no.1
• /
• pp.55-62
• /
• 1993

The author has synchronously recorded the average electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muacles and the masseter muscles. The marious levels of occlusal force were checked during clenching the resin plates which are made to fit each of the maxillary and the mandibular teeth. These activities were recorded in order to study the EMG activity pattern of the sternocleidomastoid muscle during the masticatory function of the jaw in 11 healthy subjects. The obtined results were as follows : 1. The electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muscles and the masseter muscles were increased as the occlusal force increased, and the sternocleidomastoid muscles have a lineal correlationship with the occlusal force. 2. The sternocleidomastoid muscles and the masseter muscles showed higher EMG activity during clenching at the ventroflexed head position rather than at the extended head position. (p<0.05) However the EMG activities of the anterior temporal muscles showed no difference between the ventroflexed position and the extended position of the head. 3. The electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muscles and the masseter muscles during clenching are similar at the habitual position and at the retruded condylar position. 4. The electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muscles and the masseter muscles on the working side during mastication of gum and almonds are significantly higher than on the balancing side except the masseter muscles during mastication of almonds. (p<0.05, P<0.01) 5. The asymmetry of gum are lower than that during mastication of almonds. (p<0.05) The asymmetry indices of the sternocleidomastoid muscles are higher than those of the anterior temporal muscles and masseter muscles.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.4
• /
• pp.2150-2159
• /
• 2014

This study was designed to investigate the status of orthodontic treatment and facial plastic surgery among 389 patients who visited dental clinics located in Seoul and Gyeonggi Province. After the collection of data, an analysis was carried out using a spss statistical program. The analysis results are as follows. the level of satisfaction with orthodontic treatment from patients with experience of the orthodontic treatment turned out to be high(p<0.01). Women considered 3.01 to 4 million won to be reasonable cost for orthodontic treatment (p<0.05), which is higher cost recognized by men, and patients with experience of orthodontic treatment recognized 19 to 24 months as the proper orthodontic treatment period(p<0.01). In addition, women showed higher figures than men in their awareness on the need for orthodontic treatment checkups(p<0.001), and facial plastic surgery experience (p<0.01). With respect to the part of the face on which they hoped to have plastic surgery, eye plastic surgery was higher in women (p<0.01), and nose surgery turned out to be higher in patients with experience of orthodontic treatment(p<0.05). Meanwhile, women considered the eye as the most important part among other facial areas (p<0.001), and they recognized that dentist should perform plastic surgery on both jaws among facial areas(p<0.01). In conclusion, the dental medical staff should provide consultations and operate treatment systems in consideration of gender differences and needs of dental patients. In the case of orthodontic treatment for the improvement of facial appearance, especially double jaw surgery which is closely related to the oral function, professional dental medical staff needs to perform the operation, considering the special oral environment. In addition, it is determined that provision of relevant medical information and promotion of dental service is required to provide patients with correct knowledge about orthodontic treatment and facial plastic surgery.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.36 no.2
• /
• pp.80-87
• /
• 2020

Purpose: This study aims to measure the mandibular movement using JT-3D system and provide a range of mandibular movement that can serve as a good reference for diagnosing the temporomandibular disorder. Materials and Methods: This study was conducted in 60 young male and female adults. The maximum opening and closing movement was recorded using JT-3D system, and by regarding 5 times of repetitive movement as 1 cycle of movement, total 3 cycles of movement were recorded. During the maximum opening, vertical position of lower jaw, antero-posterior position, lateral deflection position, and maximum opening distance were recorded. To evaluate the reproducibility of JT-3D system, statistical analysis were conducted (α = 0.05). Results: During the maximum opening, the average value appeared at 31.56 mm vertically and 24.42 mm rearwardly, lateral deflection position 0.72 mm, and maximum opening distance 40.32 mm. There was no statistical significance in all measured values for three cycles of movement recorded with JT-3D system (P > 0.05). Conclusion: During the maximum opening, the average value appeared at 0.72 mm in lateral deflection position and the maximum opening distance at 40.32 mm, and the analysis on the maximum opening of lower jaw using JT-3D system showed sufficiently reproducible results.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.3
• /
• pp.359-371
• /
• 2010

Facial asymmetry has been found with a higher frequency (70~84%) in skeletal class III malocclusion patients. Anticipating the poor prognosis of prosthesis due to malocclusion, occlusal stability must be obtained by orthodontic treatment. Moreover, orthodontic surgery would be needed in some severe cases for better functional and esthetic results. The orthognathic surgery is performed on one jaw or two jaw depending on the results of facial diagnosis. Genioplasty may change the vertical, horizontal, sagittal position of chin by osteotomy or augmentation using implants, also. This case is about a 24 year-old male patient who visited our clinic to solve the facial asymmetry and mandibular prognathism. Skeletal class III malocclusion, maxillary canting and menton deviation to left by 13 mm were detected. Multiple ill-fitting prostheses, unesthetic maxillary anterior prostheses, and several dental caries were found. After pre-operative orthodontic treatment, Le-Fort I osteotomy, sagittal split ramus osteotomy, genioplasty, right mandibular angle augmentation were done for the correction of jaw relation and asymmetry. By diagnostic wax-up after post-operative orthodontic treatment, maxillary full mouth rehabilitation and mandibular posterior restorations were planned out. For better result, clinical crown lengthening procedure was done on #11, 12 and implant was placed on left mandibular first molar area. The patient was satisfied with the final prostheses. Because of his high caries risk, long-term prognosis will depend on the consistent maintenance of oral hygiene and periodic follow-up.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.20 no.2
• /
• pp.121-134
• /
• 2004

This article describes a clinical protocol for the conventional rehabilitation of patient diagnosed with partial anodontia. A combined dental therapy approach was used and included endodontic therapy and root capping on the maxillary central incisors, fabrication of a maxillary overdenture, and fabrication of mandibular konus overdenture supported by 3 konus abutments. Within this protocol, tooth-supported overdenture prostheses are used for 2 purposes: first, to obtain the most rigid retention and function at an established maxillary-mandibular relationship; and second, to continuously maintain function and esthetic appearance applying immediate dentures after teeth extraction. The idea behind this protocol and its associated clinical procedures is presented along with a discussion compared with implant therapy. In the case introduced, and after 7 years of observation, the therapy can be seen as a success. We increased the occlusal vertical height in this case, but it would be more appropriate to see this as recovering the occlusal vertical height that was lost. The process of increasing the occlusal vertical height, that is restoration of the face, modification of the extrinsic occlusion of the incisors, and retraction of the mandible is very difficult and important. Ultimately, class III malocclusion is fixed, adequate occlusal vertical height is gained, and the retracted posterior anodontial portion is restored by prosthodontic dentures based on the rigid support theory. The result of the therapy done on the later-achieved malocclusion with partial anodontia on the posterior portion must consider the following in order to maintain the safety of the esthetics of the tooth and face for a period of time: 1) occlusal restoration with an ideal occlusal vertical height, 2) allowance of the final occlusion induced by the functional relationship of the upper and lower jaw, 3)final occlusion functionally induced by the lip competence limit.

• The korean journal of orthodontics
• /
• v.35 no.5 s.112
• /
• pp.398-407
• /
• 2005

The present study was conducted to examine the morphometrics and function of the disk on both sides among patients with facial asymmetry (FA) and to elucidate plausible correlations between internal derangement (ID) and FA. The sample was composed of 10 males and 27 females with FA. The disk status of all subjects was evaluated by bilateral high resolution magnetic resonance scans in the sagittal (closed and open) and coronal (closed) planes. Five types of disk displacement were identified accordingly. The disk function was diagnosed as normal disk function, disk displacement with reduction, and disk displacement without reduction. The disk shape on sagittal MRI in closed position was classified as bi-concave, biplanar, funnel/hemiconvex, and deformed. The disk position, translation and rotation were also measured. The difference between the shifted side and non-shifted side was analyzed by statistical analysis. Approximately $70\%$ of the patients in the present study showed unilateral or bilateral ID. It was found that anterior disk displacements (ADD), especially rotational ADD, occurred more frequently in the shifted side, while normal disk position was observed mainly in the non-shifted side (p<0.01). The disk of the shifted side showed significantly deformed configuration and inferior-anterior disk position. However, the disk of the non-deviated side showed hyper-mobility during jaw opening movement. These results demonstrate that in FA patients, the disks status of the shifted side is different from that of the non-shifted side, a phenomenon that could be correlated to facial asymmetry.