• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.34 no.5
• /
• pp.537-542
• /
• 2008

BSSRO is most frequently operated among orthognathic surgery techniques for repairment of maxillofacial deformities. In case of patients with maxillofacial asymmetry accompanying mandibular protrusion who are operated by BSSRO, this study considers the recovering time for masticatory force of each tooth and Masseteric EMG and the adequate time enabling normal occlusion. The patients who are operated with BSSRO under general anesthesia in Dankook Dental Hospital, Department of OMS are selected for this study. The control group is devided into 2. 26 patients with facial asymmetry accompanying mandibular protrusion are selected for group 1 and their maximum voluntary bite force and masseteric EMG are measured. Group 2 is formed by volunteers with healthy dentition who are measured maximum bite force and masseteric EMG on both sides of the mouth. At the week of 3rd, 5th, 7th, 9th and 11th, Mann-Whitney U test is carried on for statistical analysis and the result is as follows. 1. Patients with mandibular protrusion showed apparently low maximum bite force and masseteric EMG than patients with normal occlusion. 2. In comparison with control group 1, Occlusal force is regained in incisors and canines at the 9th week and in premolars and molars, 11th week and masseteric EMG is regained at 11th week. 3. Comparing to normal occlusal patients, no recovery could be found in experimental group in every parts of the mouth.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.3
• /
• pp.214-218
• /
• 2009

The occlusal force of the tooth leads to loss of tooth tissue owing to attrition and abrasion, and may cause abfraction and pathological change of the dentin. Thus, we developed finite element models, examined them by applying ordinary occlusal force, and analyzed the stress distribution. Specimens used were mandibular first premolars from 15 Korean males and 13 females and were made into finite element models from medical images that were obtained using a Micro-CT. We have found that the irregular feature of the tooth is not only useful to masticating and pronouncing as well known, but it is also suitable for protecting inner tissue by dispersing stress and delivering proper pressure to periodontal tissue to continue a physiological action. Also, image analysis could let us know the factor that is the cause of a disorder due to stress concentration in the cervical line. These results are expected to support the field of dental treatment planning, operating procedure and clinical trial, and the advance of technical expertise to develop implants and dentures.

• Journal of Technologic Dentistry
• /
• v.36 no.4
• /
• pp.231-237
• /
• 2014

Purpose: This study was performed fracture strength test by conducted change of abutment and coping shape for suggesting monolithic all ceramic crown which has thin thickness and superior strength of the occlusal surface. Methods: The specimens on the four kinds abutment was made according to thickness of occlusal surface and angle of axis surface. And All ceramic coping specimens of 6 different kinds was made by the CAD/CAM Method. Compression strength test using the UTM and the verification of compression-stress situation using the 3D finite element method were conducted under optimum conditions. Results: 516C specimen was showed the strongest compression-fracture strength, followed by 516FR, 516F45, specimens. Did not show significant differences between 516FR and 516F45. 516C of the universal testing machine the specimen's surface that are within the vertical load is small, finite element method of a uniformly distributed load, so the value received suggests otherwise. Conclusion: In conclusion, abutments of monolithic ziconia ceramic when having a same thickness of the occlusal, as the angle of occlusal edge is small, the stress is well dispersed and it can endure well in the fracture.

• Journal of Oral Medicine and Pain
• /
• v.43 no.4
• /
• pp.142-146
• /
• 2018

Patients with temporomandibular disorder often present with acute occlusal change and properly managed with conservative treatment. If such change is caused by unusual etiology, differential diagnosis may be challenged. This article describes the diagnosis of a patient exhibiting pain and acute posterior open bite on the ipsilateral side after chewing hard food. After initial conservative treatment failed to resolve the complaint, magnetic resonance imaging was ordered and confirmed partial perforation of articular disc. Disc perforation itself is usually chronic in nature, but sudden macrotrauma may also cause the disorder. However, occlusal discrepancy caused by disc perforation is rare and seldom reported. We present a case of acute malocclusion caused by disc perforation with a review of related literature.

• The Journal of Korean Academy of Prosthodontics
• /
• v.37 no.1
• /
• pp.23-41
• /
• 1999

During the previous several decades the osseointegrated implants have been considered as the most ideal therapy for the fully edentulous or partially edentulous patients. Although the research on the biocompatibility of osseointegration, the oral tactile function, and the histo-neurologic study had been performed, the change of the oral tactile sensibility and maximal occlusal force according to the postinsertion time of implant prostheses has not been studied. The purpose of this study was to compare the oral tactile sensibility and maximal occlusal force of implant pros-theses to natural teeth according to the specific postinsertion time intervals. The fifty seven patients treated with $Br{\aa}nemark$ implants during the recent seven years were involved in this study. The oral tactile sensibility and maximal occlusal force were measured according to the postinsertion time (${\leqq}6\;months,\;{\leqq}12\;{\leqq}\;18\;months\;{\leqq}\;24\;months,\;and\;{\geqq}20\;months$) 1. The passive tactile threshold of implants was higher than 6-7 times when comparing to natural teeth(P<0.05) 2. The absolute pressure threshold in horizontal and vertical direction for the passive tactile sensibility had decreased significantly in the post insertion time 13-18 months group and had increased significantly in the post insertion time over 25 months group (P<0.05) 3. 50% limit thickness and 100% absolute thickness for the active tactile sensibility had decreased significantly in the postinsertion time 7-12 months group ($AT_{50}:P<0.005,\;AT_{100}:P<0.05$) 4. The maximal occlusal force of the implants prostheses had decreased when comparing with natural teeth in the postinsertion time 1-6 months group(P<0.05) and after that there was no significant difference between the implant prostheses and natural teeth(P<0.05) 5. Maximal occlusal force according to the postinsertion time had increased significantly in the 13-18 months group (P<0.05) after that there was no significant difference. 6. There was positive correlation between age and oral tactile sensibility tested in horizontal and vertical direction ($P_{H:r}=0.39,\;P_{v:r}=0.41$) and there was no correlation between age and maximal occlusal force, age and active tactile sensibility 7. According to the results or the questionnaire, 76.6% of the patients were satisfied with the function and 96.7% of the patients were satisfied with the sensibility. In conclusion oral tactile sensibility and maximal occlusal force of implants have changed with the postinsertion time. Oral tactile function of implants was lower than that of the natural teeth, but for the maximal occlusal force there was no difference between implants and natural teeth.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.35 no.2
• /
• pp.90-97
• /
• 2019

Purpose: Previous studies related with occlusal contact area were limited that interocclusal thickness level or the method of measurement has not been accurate in measuring. The purpose of this study was to investigate the relation between head posture and occlusal contact area using photo occlusion analysis. Materials and Methods: 54 subjects with complete dentition (44 men, 10 women / 23 to 33 years of age) were included. To identify the relationship between head posture and occlusal contact area, subjects took interocclusal record in maximal intercuspal position with three different positions(supine position ($0^{\circ}$) / inclined position ($45^{\circ}$) / upright position ($90^{\circ}$)) on the dental unit chair. Occlusal contact area was analyzed using photo occlusion analysis. Statistical analyses were performed with SPSS ver.25.0 at 95% confidence interval. Results: Head posture has no significant effect on the changes of occlusal contact area (P > 0.05). Conclusion: When interocclusal relation is stable, head posture does not change a interocclusal record because head posture has no significant effect on occlusal contact area. Analysis of occlusal contact area using photo occlsion analysis device is useful due to its material property and simplicity.

• The Journal of Korean Academy of Prosthodontics
• /
• v.26 no.1
• /
• pp.99-111
• /
• 1988

The purpose of this study was to investigate the influence of the occlusal interference on the activity of anterior temporal and masseter muscles during maximal biting. In seven subjects, cast hard gold cap providing new occlusal surface approximately 0.5mm above its occlusal level was cemented on the mandibular right first molar during aquired experimental period. EMG recordings were taken bilaterally during one second hardest possible clenching four times. This procedure was done not only before, immediately after, 48 hours after and one week after cementation of interfering crown but also immediately after and one week after removal of occlusal interfering crown. The results were as follows : 1. Immediately after cementation of interfering crown, the activity was significantly decreased in all muscles studied. 2. One week after cementaion of interfering crown, the lowest muscle activity was recorded. But clinical sign and symptoms were significantly subsided. 3. Immediately after removal of interfering crown, the activity was increased in all muscles studied. 4. One week after removal of interfering crown, the activity of masseter muscles was increased to the level of before cementation of interfering crown. 5. There was no significant activity difference between right and left in the muscle studied. 6. Masseter muscle activity showed significant change than anterior temporalis with the unilateral mandibular posterior tooth interference.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.32 no.1
• /
• pp.47-59
• /
• 2016

Purpose: The aim of this study was to investigate the changes in occlusal force after loss of the lower first molar depending on the inclination and extrusion of the adjacent and opposing teeth by using a strain gauge. Materials and Methods: Anatomic teeth were used to reconstruct the normal dental arch with loss of the lower right first molar. A uniformly thick layer of silicone was applied to the root to mimic the periodontal ligament. Four stages of dies with varying degrees of inclination and extrusion of the adjacent and opposing teeth were constructed and attached to master model interchangeably by using a CAD/CAM fabricated customized die system. The strain gauges were attached to teeth and a universal testing machine was used to determine the changes in occlusal force. An independent t-test and one-way ANOVA were performed (${\alpha}=.05$). Results: While simulating chewing food, the upper first, second premolar and lower second molar showed greater occlusal force than before extraction. When the change of adjacent teeth's occlusal force with their progressive movement after molar loss was evaluated, the difference among four die models was significant and was in the decreasing aspect (P < 0.05). Conclusion: When the lower first molar was lost and the adjacent teeth did not move yet, the occlusal force in adjacent teeth was higher than that when the lower first molar still existed. In addition, the occlusal force in the upper premolars and lower second molar decreased significantly with the progressive movement of adjacent teeth.

• The korean journal of orthodontics
• /
• v.30 no.1 s.78
• /
• pp.91-99
• /
• 2000

This study was done to identify the changes of bite force and occlusal contact between before and after stabilization splint therapy. 16 female patients, accepted for orthodontic treatment at the Department of Orthodontics, College of Dentistry, Chosun University, were selected as the sample of this investigation. For comparisons, the samples of 16 were divided into just before stabilization splint, 1 month after stabilization splint, 2 months after stabilization splint, and 3 months after stabilization splint and used the T-scan system to identify the bite force and occlusal contact changes for each group. Statistical analysis of the data was carried out ANOVA tests, and Turkey tests using $SPSS/PC^+$. The results were as follows : 1. Bite force change from just before treatment to 1 month after stabilization splint therapy was statistical significantly decreased (P<0.05). 2. Bite force changes from 1 to 3 months after stabilization splint therapy showed no statistical significance (p>0.05). 3. The changes of anterior occlusal contacts showed no statistical significance regardless of the wearing periods of stabilization splint (P>0.05). 4. The changes of posterior occlusal contacts from just before treatment to 1 month after stabilization splint therapy was statistical significantly decreased (P<0.05). 5. The changes of posterior occlusal contacts Outing 1 to 3 months after stabilization splint therapy showed no statistical significance (P>0.05). 6. Posterior teeth rather than anterior teeth were more influenced by the changes of the number of occlusal contacts. To sum up above results, we may respect to capturing and stabilizing centric relation Position just 1 month after stabilization splint therapy.

• The korean journal of orthodontics
• /
• v.34 no.3 s.104
• /
• pp.229-240
• /
• 2004

The purpose of this study was to evaluate the compensatory changes of occlusal plane angle in relation to skeletal factors. Lateral cephalograms of 61 adults with normal occlusion and 92 adults with skeletal malocclusions were traced and measured to analyze skeletal factors and occlusal plane angles. In terms of horizontal relationships, the normal occlusion group and malocclusion group were classified Into subgroups of skeletal Classes I, II, and III, while in terms of vertical relationships, each group was also classified into horizontal , average, and vertical subgroups. Some measurements were evaluated statistically by ANOVA and Post Hoc, and the others were reviewed by Paired t-tests. In this study, only the occlusal plane angle to AB plane did not show a significant difference between the normal occlusion group and malocclusion group. After treatment, the occlusal plane angle to the AB plane of the malocclusion group was approximated to that of normal occlusion group. The LOP to AB plane angle of the normal occlusion group was 91.7 in skeletal Class I, 88.8 in skeletal Class II, and 93.5 in skeletal Class III. This study was done to assess the treatment changes of the occlusal plane in the malocclusion group, and to draw a comparison with the normal occlusion group in order to present a reference to establish a new occlusal plane inclination.