• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.323-331
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• 1995

This study was undertaken to investigate the changes of tooth contacts following orthodontic treatment , using T-Scan system. Occlusal contacts in maximum intercuspation were examined in 26 patients at the end of the active phase of orthodontic treatment and again 3 months into the retention phase to abbess the initial posttreatment occlusal changes. The obtained results of this study were as follows : 1. The mean total number of contacts increased from 11.27 at the end of orthodontic treatment to 13.15 at the fellow up visit, which was found to be statistically significant (P<0.05). 2. The change of number of contacts on anterior teeth was unchanged. 3. The change of number of contacts on posterior teeth was found to be statistically significnat (P<0.01). 4. The change of fetal number of teeth in contact was significant (P<0.05). 5. The number of ant. teeth in contact was slightly increased. but Which was not found to be statistically significant (P>0.05). 6. The number of post. teeth in contact significantly increased, which was statistically significant (P<0.05). 7. A statistically significant relationship was found between the total number of contacts at the end of treatment and the change in the contacts over time. The fewer the number of tooth contact was at the end of orthodontic treatment, the greater number of tooth contact increased over time(r=-0.38, P<0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.3
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• pp.243-249
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• 2018

Excessive tooth wear results in unacceptable damage to the occlusal surface and can cause pulpitis, occlusal disharmony, dysfunction, and unesthetic result. Patients with severe attrition have to be classified as several types relative to the vertical dimension of occlusion (VDO) and the interocclusal distance for the prosthetic space. The patient in this case was a 80 - year - old woman who lost support of posterior occlusion and collapsed of the occlusal plane due to confrontation of the opposing teeth, accompanied by an increase in the number of remaining bristles, resulting in a loss of intermaxillary space for prosthesis. In this case, treatment with increased vertical dimension may have stability if the increase in vertical occlusal height is minimized within the required range, and a stable occlusal contact is provided after an increased vertical occlusal height stabilization period. After the new VDO had been confirmed under interim fixed restorations, definitive fixed restorations were produced. Through these treatment processes, we obtain satisfactory results that are functional and aesthetically pleasing.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.4
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• pp.627-646
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• 1997

In order to find the degree of osseointegration at bone-implant interface of clinically successful implants, models including the 3.75mm wide, 10mm long screw type $Br{\aa}nemark$ implant as a standard and cylinder, 15mm long, 5.0mm wide, two splinted implants, and implants installed in various cancellous bone density were designed. Also, the amount of load and material of prostheses were changed. The stress and minimum contact fraction were analyzed on each model using three-dimensional finite element method(I-DEAS and ABAQUS version 5.5). The results of this study were as follows. 1. 10mm long, 3.75mm diameter-screw type implant had $36.5{\sim}43.7%$ of minimum contact fraction. 2. Cylinder type implant showed inferior stress distribution and higher minimum contact fraction than screw type. 3. As implant length was increased, minimum contact fraction was increased a little, however, maximum principal stress was decreased. 4. Implants with a large diameter had lower stress value with slightly higher minimum contact fraction than standard screw type. 5. Two splinted implants showed no change of minimum contact fraction. 6. The higher bone density, the lower stress value. 7. The material of occlusal surface had no effect on the stress of the bone-implant interface.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.73-80
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• 2007

Compomer that release fluoride could be used on proximal caries of child effectively. But oral cavity is always wet, so saliva inhibits bonding of tooth and compomer. When the saliva exist on bonding, it can be occured microleakages. The purpose of this study was to evaluate the influence of salivary contamination on compomer restoration and degree of microleakage according to restoration methods. Dyract $AP^{(R)}$ and prime and $bond^{(R)}$ NT was applied by the manufacture s instructions. Elipar Trilight was applied for light curing. Saliva pool was made for reconstruction of oral cavity. Two premolar was embedded in acrylic resin. After class II cavity preperation, Dyract $AP^{(R)}$ was restored under several condition, the specimen was thermocycled 500 times with 30 second dwell time. 0.5% methylene blue was used for microleakage test. Micoleakage was measured by the ratio of the infiltration length to occlusal and gingival side interface. Data were analyzed statistically using Kruskal Wallis Test, Mann-Whitney Test. The Result were as follows ; 1. In occlusal side, there were no statistical differences. 2. In gingival side, there were no statistical differences in Group III ($ContactMatrix^{TM}$, Rubber dam, $Oraseal^{(R)}$), Group IV (No saliva contamination). 3. In gingival side, there were no statistical differences in Group I$(ContactMatrix^{TM})$, II($ContactMatrix^{TM}$, Rubber dam). 4. In gingival side, there were statistical differences in Group I$(ContactMatrix^{TM})$, II($ContactMatrix^{TM}$, Rubber dam).

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.17-22
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• 1984

A clinical evaluation was made on teeth in 113 subjects from ages 19 to 23 with Angle's Class I occlusion who were free from prosthesis, orthodontics, and occlusal equilibration. The study was made to determine if there was a relation between the type of occlusion, non-working contact and temporomandibular dysfunction. From the foregoing study, the author obtained the following results. 1. In lateral excursion, there was not any significant difference between bilateral canine protected occlusion (31%), bilateral group function (32.7%), and mixed type (34.5%). 2. Only 10 of 113 subjects studied had non-working side tooth contacts (8.2 per cent). 3. Twenty per cent of subjects with non-working side contact showed temporomandibular joint dysfunction. 4. Non-working side contacts were not observed in subjects with canine guided occlusion. 5. It would be premature to relate the type of occlusion on working side directly to temporomandibular joint dysfunction.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.2
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• pp.162-167
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• 2010

This is a case report about patient who had suffered from degenerative joint disease and treated by TMJ reconstruction with condylar prosthesis. The patient visited Korea University An-am hospital on 2007 complaining symptom about both TMJ pain, mouth opening limitation and open bite. From CT view there was severe resorption of both condylar head, therefore condylar prosthesis reconstruction was planned. After 3D RP model analysis for preparation, the patient was operated under general anesthesia for condylar prosthesis reconstruction and the symptom was alleviated. (increased mouth opening, reduced anterior open bite, full mouth occlusal contact achieved) Follow up was carried out monthly, but after this, patient refused follow up. After 26 months from the operation, the patient revisited for anterior open bite. In clinical evaluation, occlusal contact was remained, but anterior open bite was relapsed. From cephalometry analysis, severe resorption of glenoid fossa was found. Therefore, Autogenous disc reconstruction with alloplastic material was planned on August 2009. After another surgery, condylar prosthesis was regained its normal position in glenoid fossa, and occlusion was recovered properly.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.195-201
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• 2022

Hemimandibulectomy and free fibular flap (FFF) in patients with squamous cell carcinoma could disturb the functional movement of the mandible. The muscular function in the sectioned side was compromised because of the incompetency of the muscle attachment to the mandible, leading to the unstable occlusal contact in the centric and eccentric occlusion. In this report, we present a case of a 63-year-old male who underwent cancer surgery and reconstruction with fibular graft, and he needed a fixed dental prosthesis to restore tooth loss in the anterior region. Occlusal contact change and instability were found according to the bite force in the centric relation and eccentric movement. This case report aimed to present the prosthetic procedure for fabricating the functionally optimized fixed prosthesis wherein the functionally generated path (FGP) technique and digital imaging method were applied to replicate mandibular movement and vertical dimension of the patient.

• The Journal of Advanced Prosthodontics
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• v.13 no.2
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• pp.79-88
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• 2021

Purpose. To assess peri-implant stress distribution using finite element analysis in implant supported fixed partial denture with occlusal schemes of cuspally loaded occlusion and implant protected occlusion. Materials and methods. A 3-D finite element model of mandible with D2 bone with partially edentulism with unilateral distal extension was made. Two Ti alloy identical implants with 4.2 mm diameter and 10 mm length were placed in the mandibular second premolar and the mandibular second molar region and prosthesis was given with the mandibular first molar pontic. Vertical load of 100 N and and oblique load of 70 N was applied on occlusal surface of prosthesis. Group 1 was cuspally loaded occlusion with total 8 contact points and Group 2 was implant protected occlusion with 3 contact points. Results. In Group 1 for vertical load, maximum stress was generated over implant having 14.3552 Mpa. While for oblique load, overall stress generated was 28.0732 Mpa. In Group 2 for vertical load, maximum stress was generated over crown and overall stress was 16.7682 Mpa. But for oblique load, crown stress and overall stress was maximum 22.7561 Mpa. When Group 1 is compared to Group 2, harmful oblique load caused maximum overall stress 28.0732 Mpa in Group 1. Conclusion. In Group 1, vertical load generated high implant stress, and oblique load generated high overall stresses, cortical stresses and crown stresses compared to vertical load. In Group 2, oblique load generated more overall stresses, cortical stresses, and crown stresses compared to vertical load. Implant protected occlusion generated lesser harmful oblique implant, crown, bone and overall stresses compared to cuspally loaded occlusion.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.45-55
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• 2005

As people prefer to use right or left hand, some have preferred chewing side while others do not. Totally, 82 volunteers composed of students and staffs from Dental Hospital College of Dentistry Yonsei University participated in this study for the investigation of influence of preferred chewing habit, that has lasted for more than a year, on electromyographic(EMG) activity of masticatory muscles and bite force. Among the 82 volunteers, 46 had preferred chewing habit while the other 36 did not. Prior to the investigation, those with factors that could affect the study, such as, general disease, irregular dentition and malocclusion, were screened and excluded by questionnaire and clinical examination. The results were as follows: 1. There was no significant difference in EMG activities between chewing side and non-chewing side of preferred chewing subjects at rest as well as maximal voluntary contraction(MCV)(p>0.05). 2. Asymmetrical coefficient of temporal and masseter muscle EMG activities between preferred chewing subjects and non-preferred chewing subjects at rest was not significantly different(p>0.05). 3. Asymmetrical coefficient of masseter EMG activity was significantly higher(p<0.05) than that of non-preferred chewing subjects at MCV, whereas that of anterior temporal muscle showed no difference(p<0.05). 4. In preferred chewing subjects, there was no significant difference in average bite force and occlusal contact area between chewing side and non-chewing side(p>0.05). 5. There was no significant difference in Asymmetrical coefficients of average bite force and occlusal contact area between preferred chewing subjects and non-preferred chewing subjects (p>0.05). Consequently, preferred chewing habit can be considered as physiological asymmetry with normal function rather than to have influence on EMG muscle activity of masticatory muscles, average bite force and occlusal contact area. Objective standardization to differentiate preferred chewing subjects and non-preferred chewing subjects should be established in the further study.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.1
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• pp.50-58
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• 2000

The purpose of this study was to investigate the causes of food impaction and to explore solutions as well. For this study, 39 patients with food impaction were selected. 77 contact areas in these patients were investigated mobility, tightness of contact area, gingival index, plaque index, attachment loss, alveolar bone loss, proximal caries, marginal ridge distance and occlusal relationships. The results were as follows ; 1. Teeth without distal support were found to be the most frequent site of food impaction (41.6%). Food impaction was found to be more frequent in the upper teeth (65.2%) than the lower teeth (33.8%). 2. Food impaction was found in tight contact cases (71.4%). Alveolar bone loss was not found in the early stage of food impaction (83.1%) 3. The distance between the marginal ridges of food impaction sites (mean=0.48mm) was short-er than that of the control group. (mean=0.77mm) (p<0.001) 4. In 18.2% of the cases, proximal carries were found at the food impaction site. 5. Food impaction affected patient's occlusion with the following frequencies, cusp to marginal ridge relationship (72.7%), cusp to fossa relationship (3.9%) and stepped relationship (23.4%).