• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.310-320
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• 2000

Statement of the problem. The record base in fabricating procedures of the complete denture, as a temporary form for reproducing denture base, is used to record upper and lower jaw relation and to align artificial teeth and try-in it in the mouth. The accuracy of jaw relation record is affected by the accuracy, stiffness and stability of the record base. So, the accuracy of record base is the most important requirements of jaw relation records. Purpose of study. The purpose of this study was to evaluate the gap that occurred over the palatal area of a maxillary record base fabricated with autopolymerizing resin and light-curing resin. Methods/material. The maxillary record bases were fabricated out of autopolymerizing resin that is used the most frequently in clinics and light-curing resin that attracts special attention for its several merits. The light-curing resin was made by two kinds of polymerization methods, which are one step curing method and multiple step curing method. All record bases were cut in certain positions of the master cast 1 hour and 1 day later after fabrication and the accuracy of the master cast was measured and analyzed with a microscope. Results. A pattern of gap formation between the record base and the maxillary cast was observed in all specimens. According to kinds of resins, autopolymerizing resin was significantly more accurate than light-curing resin. There was no statistical difference according to time lapse, and in all three groups, the maximum discrepancy occurred at the posterior border in the mid-palatal region. Conclusion. The autopolymerizing resin is better than light-curing resin, and multiple step curing method is more accurate than one step curing method when using light-curing resin.

• Archives of Plastic Surgery
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• v.44 no.1
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• pp.19-25
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• 2017

Background Numerous condylar repositioning methods have been reported. However, most of them are 2-dimensional or are complex procedures that require a longer operation time and a highly trained surgeon. This study aims to introduce a new technique using a condylar repositioning plate and a centric relation splint to achieve a centric relationship. Methods We evaluated 387 patients who had undergone surgery for skeletal jaw deformities. During the operation, a centric relation splint, intermediate splint, final centric occlusion splint, and condylar repositioning plate along with an L-type mini-plate for LeFort I osteotomy or a bicortical screw for bilateral sagittal split ramus osteotomy were utilized for rigid fixation. The evaluation included: a physical examination to detect preoperative and postoperative temporomandibular joint dysfunction, 3-dimensional computed tomography and oblique transcranial temporomandibular joint radiography to measure 3-dimensional condylar head movement, and posteroanterior and lateral cephalometric radiography to measure the preoperative and postoperative movement of the bony segment and relapse rate. Results A 0.3% relapse rate was observed in the coronal plane, and a 2.8% relapse rate in the sagittal plane, which is indistinguishable from the dental relapse rate in orthodontic treatment. The condylar repositioning plate could not fully prevent movement of the condylar head, but the relapse rate was minimal, implying that the movement of the condylar head was within tolerable limits. Conclusions Our condylar repositioning method using a centric relation splint and miniplate in orthognathic surgery was found to be simple and effective for patients suffering from skeletal jaw deformities.

• Phonetics and Speech Sciences
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• v.5 no.1
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• pp.109-121
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• 2013

This study examined several kinematic properties of the primary articulator (the tongue dorsum) and the supplementary articulator (the jaw) in the articulation of the voiceless velar stop (/k/) within nonassimilating contexts. We examined in particular the spatiotemporal properties (constriction duration and constriction maxima) from the constriction onset to the constriction offset by analyzing a velar (/k/) followed by the coronal fricative (/s/), the coronal stop (/t/), and the labial (/p/) in across-word boundary conditions (/k#s/, /k#t/, and /k#p/). Along with these measurements, we investigated intergestural temporal coordination between C1 and C2 and the jaw articulator in relation to its coordination with the articulation of consonant sequences. The articulatory movement data was collected by means of electromagnetic midsagittal articulometry (EMMA). Four native speakers of Seoul Korean participated in the laboratory experiment. The results showed several characteristics. First, a velar (/k/) in C1 was not categorically reduced. Constriction duration and constriction degree of the velar (/k/) were similar within nonassimilating contexts (/k#s/=/k#t/=/k#p/). This might mean that spatiotemporal attributes during constriction duration were stable and consistent across different contexts, which might be subsequently associated with the nontarget status of the velar in place assimilation. Second, the gestural overlap could be represented as the order of /k#s/ (less) < /k#p/ (intermediate) < /k#t/ (more) as we measured the onset-to-onset lag (a longer lag indicated shorter gestural overlap.). This indicates a gestural overlap within nonassimilating contexts may not be constrained by any of the several constraints including the perceptual recoverability constraint (e.g., more overlap in Front-to-Back sequences compared to the reverse order (Back-to-Front) since perceptual cues in C1 can be recovered anytime during C2 articulation), the low-level speech motor constraint (e.g., more overlap in lingual-nonlingual sequences as compared to the lingual-lingual sequences), or phonological contexts effects (e.g., similarity in gestural overlap within nonassimilating contexts). As one possible account for more overlap in /k#t/ sequences as compared to /k#p/, we suspect speakers' knowledge may be receptive to extreme encroachment on C1 by the gestural overlap of the coronal in C2 since it does not obscure the perceptual cue of C1 as much as the labial in C2. Third, actual jaw position during C2 was higher in coronals (/s/, /t/) than in the labial (/p/). However, within the coronals, there was no manner-dependent jaw height difference in C2 (/s/=/t/). Vertical jaw position of C1 and C2 was seen as inter-dependent as higher jaw position in C1 was closely associated with C2. Lastly, a greater gap in jaw height was associated with longer intergestural timing (e.g., less overlap), but was confined to the cluster type (/kp/) with the lingual-nonlingual sequence. This study showed that Korean jaw articulation was independent from coordinating primary articulators in gestural overlap in some cluster types (/k#s/, /k#t/) while not in others (e.g., /k#p/). Overall, the results coherently indicate the velar stop (/k/) in C1 was robust in articulation, which may have subsequently contributed to the nontarget status of the velar (/k/) in place assimilation processes.

• The korean journal of orthodontics
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• v.47 no.3
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• pp.186-194
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• 2017

Objective: To investigate the differences in oral health-related quality of life (OHRQoL) and self-reported jaw function between patients with hyperdivergent and normodivergent facial types. Methods: Eighty patients with a distinctively hyperdivergent facial type (mandibular plane angle greater than 2 standard deviations, or $42^{\circ}$) and 80 controls were individually matched according to age, sex, ethnicity, and treatment stage. Data were collected using self-report questionnaires such as the Oral Health Impact Profile (OHIP-14) and Jaw Functional Limitation Scale (JFLS-8). Results: The mean age of the patients was $17.2{\pm}4.6years$ (range, 12-49 years), with most (65.0%) being female and of New Zealand European origin (91.3%). Individuals with hyperdivergent facial types had higher overall and social domain scores on the OHIP-14 (p < 0.05) than did the ones with normodivergent facial types. However, the intergroup differences in JFLS-8 scores were not significant (p > 0.05). Conclusions: Jaw function appears to be similar in individuals with hyperdivergent and normodivergent facial morphologies. However, those with hyperdivergent facial types are more likely to self-report poorer OHRQoL than are those with normal faces, especially in relation to social aspects.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.378-384
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• 2020

For patients with unstable mandibular movements and centric relation of the mandible due to long-term use of ill-fitting dentures, the successful fabrication of new dentures is challenging. Before fabrication new dentures, registration of centric relation is the critical point in such cases. In this case, treatment dentures with a flat occlusal table were used to stabilize mandibular movements and to register centric relation. In order to reflect the patient's jaw relation and vertical dimension obtained through the treatment dentures to the final denture, the treatment dentures were digitally duplicated, and impressions and jaw relations were obtained using the duplicated therapeutic dentures. The clinical results were satisfactory on the aspect of aesthetic and masticatory functioned.

• The Journal of the Korean dental association
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• v.12 no.1
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• pp.29-34
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• 1974

In order to appreciate the school dental services of the primary, middle, and high school and to get the basic data for the university dental service programs in Korea, the author had examined the oral health status of 1,300 freshmen in S University. Then, the followed results were obtained from the calculation and evaluation of DEMT index, DT index, MT index, FT index, DT rate, MT rate, FT rate, debris deposit rate, calculus deposit rate, periodontal disease rate, and abnormal jaw relation rate. 1. DMFT index in the freshmen was higher than that of the Korean youth in the same age. 2. It seems the above result to be appeared from the influence of the intake of the more carbohydrate foods in the freshmen. 3. In the freshmen, MT rate was lower, and FT rate higher than in the Korean youth in the same age. 4. The oral hygiene condition was good in 3.15% of the freshmen. 5. Calculus was not deposited in 8.69% of the freshmen. 6. In 9.69% of the freshmen, the periodontium was healthy. 7. In Korea, the school dental services in the primary, middle, and high schools must be improved. 8. There was the abnormal jaw relation in 12.92% of the freashmen.

• The Journal of Advanced Prosthodontics
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• v.13 no.6
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• pp.361-372
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• 2021

PURPOSE. To improve the clinical effects of complete denture use and simplify its clinical application, a digital complete denture restoration workflow (Functional Suitable Digital Complete Denture System, FSD) was proposed and preliminary clinical evaluation was done. MATERIALS AND METHODS. Forty edentulous patients were enrolled, of which half were treated by a prosthodontic chief physician, and the others were treated by a postgraduate student. Based on the primary impression and jaw relation obtained at the first visit, diagnostic denture was designed and printed to create a definitive impression, jaw relation, and esthetic confirmation at the second visit. A redesigned complete denture was printed as a mold to fabricate final denture that was delivered at the third visit. To evaluate accuracy of impression made by diagnostic denture, the final denture was used as a tray to make impression, and 3D comparison was used to analyze their difference. To evaluate the clinical effect of FSD, visual analogue scores (VAS) were determined by both dentists and patients. RESULTS. Two visits were reduced before denture delivery. The RMS values of 3D comparison between the impression made via diagnostic dentures and the final dentures were 0.165 ± 0.033 mm in the upper jaw and 0.139 ± 0.031 mm in the lower jaw. VAS ratings were between 8.5 and 9.6 in the chief physician group, while 7.7 and 9.5 in the student group; there was no statistical difference between the two groups. CONCLUSION. FSD can simplify the complete denture restoration process and reduce the number of visits. The accuracy of impressions made by diagnostic dentures was acceptable in clinic. The VASs of both dentists and patients were satisfied.

• The korean journal of orthodontics
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• v.24 no.4 s.47
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• pp.945-956
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• 1994

In the past the jaw and occlusal relationship in centric occlusion were merely considered in case of orthodontic diagnosis and treatment planning. As the fact that functional disturbance of the temporomandibular joint may be caused by occlusal interference was recognized, the importance of functional occlusion and centric relation is emphasized today. Known the importance of centric relation, there are various opinions about definition of centric relation and its taking methods. The purpose of this study was to investigate the relative centric condyle position and to compare the reproducibility of the recordings utilizing different centric relation records obtained by different taking methods. The 15 adults with normal occlusion were participated in this study. Every four centric relation records were taken in each of three methods - leaf gauge, Dawson and myomonitor method. Then the relative centric condyle position, the distance between the condylar position in centric occlusion and the position in centric relation and the reproducibility were studied using SAM 2 articulator and mandibular position indicator. The results were as follows ; 1. The trend of condyle position was different depending on centric relation taking methods. 2. The position of condyle in centric relation by leaf gauge and Dawson methods was superior to that by myomonitor method, and the position by myomonitor method was relatively antero-inferior. 3. The distance between the condylar positions in centric occlusion and the position in centric relation was longest in myomonitor method. 4. The reproducibility had little differences in transverse direction among three methods, while leaf gauge method showed the highest reproducibility and myomonitor method did the lowest reproducibility in antero-posterior and supero-inferior direction.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.199-220
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• 2015

Recently, many internet users are using mobile music service. In this paper, we aim to examine the effects of system quality factors and relation quality factors on continuance intention in the context of mobile music service. In order to analyze the antecedents of continuance intention, we introduced independent variables such as ease of use, stability, trust, involvement and unity. We also consider customer value and customer satisfaction as mediators. For empirical analysis, we surveyed 240 users of mobile music service. We conduct PLS (Partial Least Square) analysis for SEM (Structural Equation Modeling). As a result, 8 of proposed 12 hypotheses were accepted. Especially, system quality, trust and unity show positive influence on customer satisfaction significantly. Involvement and unity are positively related to customer value. Customer value and customer satisfaction show positive influence on continuance intention significantly. The results of this research can be useful guidelines for mobile music service users and providers.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.407-413
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• 2000

To evaluate the stability after orthognathic surgery in cleft lip and palate patients using rigid fixation, 20 patients underwent primary repair in childhood and later developed a jaw deformity and malocclusion that required orthognathic surgery were reviewed. Two groups, one of 10 patients performed Le Fort I osteotomy with sagittal split ramus osteotomy and one of 10 patients with sagittal split ramus osteotomy of the mandible, were evaluated. Each group had unilateral cleft only and all alveolar cleft sites had been grafted with autogeneous bone before the orthognathic surgery. The amount of surgical movement and relapse were compared in both horizontal and vertical dimensions. Two-jaw surgery group was more stable than mandibular surgery only group in mandibular position (p< 0.05). Statistically significant relapse was observed in mandibular skeletal point in mandibular surgery group (p<0.05). There was no statistically significant relapse in the skeletal point of two-jaw surgery group. However, the correlation between the horizontal surgical movement and relapse was detected (r = 0.88). This correlation indicates the need of overcorrection. The presence of scar tissues and relatively deficient maxillary bone could be attributed to this close relation between the surgical change and relapse.