• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.498-510
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• 2005

Purpose: The purpose of this study was to compare the maximum occlusal force implant prostheses to natural teeth. Material and Method: Fifty nine patients treated either with $Br{\aa}anemark$ implants and ITI implants during the recent ten years were involved in this study. The maximum occlusal force were measured with unilateral bite force recorder and dental prescale system. Results: 1. The maximum occlusal forces of the implant prostheses and natural teeth were not significantly different where measured with unilateral bite force recorder and dental prescale system. 2. The maximum occlusal forces were not significantly different between $Br{\aa}nemark$ implant and ITI implant prostheses. 3. The maximum occlusal forces of the implant prostheses had lower when compared with natural teeth during 1-6 months functional periods when measured with the unilareral bite force recorder(P<0.05) and 1-12 months functional periods when measured with the dental prescale system(P<0.05). After these periods there was not statistical significant difference between the implant prostheses and natural teeth. 4. The maximum occlusal forces of the wide diameter implant prostheses were higher than the maximum occlusal forces of the regular diameter implant prostheses when measured with dental prescale system(P<0.05), but there was no significant difference between the wide diameter and the regular diameter implant prostheses when measured with unilateral bite force recorder. 5. The maximum occlusal forces of the single implant prostheses were not significantly different with the splinting implants prostheses. 6. The maximum occlusal forces of the implant prostheses were not significantly different by age and sex. 7. There was significantly different between maximum occlusal forces measured with unilateral bite force recorder and dental prescale system(P<0.0001) but there was positive correlation(r=0.52. P<0.05). Conclusion: The maximum occlusal forces of the implant prostheses were not significantly different to natural teeth during clenching and unilateral maximum biting.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.3
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• pp.229-237
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• 2000

According to the functional matrix theory, Delaire proposes that individual occlusal plane was determined by variable effects of teeth, maxilla, mandible, cranium, cranial base and soft tissue matrix including the orofacial musculature. and that there is the ideal occlusal plane determined by the most proper spatial position of maxilla and mandible, functionally and esthetically. This study was designed to find out the relation between Delaire's ideal occlusal plane and muscle activity of masticatory muscles in individuals who have normal maxillo-mandibular relationships. Lateral cephalometric radiographs were taken and his/her individual occlusal plane and ideal occlusal plane were analyzed with Delaire's architectural and structural craniofacial analytic method. For evaluation of muscle activities of masticatory muscles, electromyography of anterior temporal muscle, superficial masseter muscle, and anterior belly of digastric muscle was recorded in fifty Korean normal Angle class I occlusion individuals. According to the average value of ideal occlusal plane, fifty normal Angle class I occlusion individuals were classified into three groups: Ideal occlusal plane group(I group), hyperrotation group(I+ group) and hyporotation group(I- group). The result of this study was as follows: 1. The results of Delaire's architectural and structural craniofacial analysis of lateral cephalography of the fifty Korean normal Angle class I occlusion individuals are that twelve persons(24%) have consistent or parallel with ideal occlusal plane and the average of angular difference was $1.22^{\circ}{\pm}3.69^{\circ}$. 2. There is no significant difference in muscle activities of masticatory muscles during resting(p<0.05), but significant increases of muscle activity of ipsilateral anterior temporal and masseter muscle, contralateral anterior belly of digastric muscle during unilateral chewing and of anterior temporal and masseter muscle during bilateral clenching(p<0.05). 3. To find out the effect of the angular difference between Delaire's ideal occlusal plane and real occlusal plane to muscle activity, muscle activities of masticatory muscles were compared with three groups in each other; I group, I+ group and I- group. The results were no significant differences during resting, unilateral chewing and bilateral clenching.(p>0.05) 4. Although there is no significant differences of masticatory muscle activities among the three groups, the fact that increasing tendency of masseter muscle activity of ideal occlusal plane group(I+) than those of any other groups(I+ and I-) during bilateral clenching was noted. There is only the implication that occlusal plane makes some effects on masticatory muscle activities, espacially that of masseter muscle during bilateral clenching. In conclusion, the hypothesis that occlusal plane is one of the factors which affect the muscle activities of masticatory muscles and that anyone whose occlusal plane consistent with Delaire's ideal occlusal plane has an extraordinary functional advantage in masticatory muscle function cannot be proven with electromyography methods.

• Journal of Korean society of Dental Hygiene
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• v.22 no.4
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• pp.225-230
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• 2022

Objectives: Patients with excessive tooth wear should first be diagnosed for the etiology of the tooth wear. Causes of tooth wear include bruxism, clenching, and taking medications for systemic diseases. After identifying the cause of tooth attrition, the final prosthesis should be restored with an appropriate vertical dimension. Methods: A 79-year-old man with worn out teeth desired a whole dental treatment. He was on medications for high blood pressure and asthma. The treatment proceeded with a consultation with a medical doctor. The medications for asthma evoked multiple teeth wear and a loss of the vertical dimension. After recovery of 3 mm of vertical dimension, 2 months of evaluation was followed by an interim prosthesis. Results: The increased vertical dimension caused no problem in function and esthetics, and the final restoration was performed with a full monolithic zirconia crown. Group function, adequate anterior guidance, and the occlusal plane were determined. Conclusions: After the final restoration, the patient was both esthetically and functionally satisfied, and a night guard splint was delivered to prevent prosthesis fracture. The patient was informed about the potential tooth wear associated with asthma drugs and educated to visit the clinic regularly.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.10
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• pp.611-617
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• 2003

A mechanical or electrical stimulation to the mandibular symphysis during a maximal voluntary clenching of the teeth always produces a jaw jerk followed by a silent period (transient stops) in the masseteric EMG (electromyogram). Generally, a mechanical stimulation is followed by a single silent period, and an electrical stimulation is followed by multiple silent periods. In this paper, we propose a new algorithm for determining the duration of the masseter silent period. The decision approach in essentially based upon a segmentation algorithm consisted of variance filter, median filter and gaussian filter. The new adaptive digital notch filter using R-CLMS(reverse constrained least mean-squared) algorithm is proposed for the elimination of powerline(60Hz) noise. At the same time, we design a real time measurement system for the EMG silent period under Window base.

• Journal of Oral Medicine and Pain
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• v.7 no.1
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• pp.32-40
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• 1982

Functional disorders of the temporomamdibular joint and masticatory system were investigated in 209 men and 110 women, ranging form 20 to 30 years old, with a method devised by Agerberg and Carlsson. The investigated persons were dental students of the School of Dentistry, Seoul National University and student nurses of the School of Medicine, Seoul National University. The obtained results were as follows : 1. Facial pain and headache were reported by 32%. 2. Pain on gaping was localized mainly to the temporomandibular area and was noted in 8%. 3. Chicking of the temporomandibular joints was reported by 26%, somewhat more often by males. 4. Clenching of the teeth was relatively common in men and biting of the lip was comman in women. 5. Prevalence of mandibular dysfunction was found in 53%.

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.153-168
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• 1994

The aim of the present study was to investigate a relation between occlusal wear area and occlusal contact patterns. For the purpose, occlusal wear area were measured in 58 dental students and in 129 patients with temporomandibular disorders(TMDs) from dental casts. Teeth used in this study were from canine to second molar on both sides in upper arch, totally ten. Occlusal wear area on casts was marked by pencil and photocopies, and then, the area was measured with planimeter. Occlusal relation was clinically examined with regard to Angle's classification, chewing side preference, lateral guidance pattern and bruxing and/or clenching habit. T-Scan, electronic occlusal contact analyzer, was used to record occlusal contact number, contact force, contact time and occlusal balance that is TLR(total left-right statistics) during tooth contact. All measurement were repeated 3 times and the average value was used for data processing. The obtained results were as follows : 1. Mean value of occlusal wear area did not differ significantly between dental students and patients. 2. There ws not significant difference in wear area between chewing side and non-chewing side in both groups. 3. Occlusal wear area was significantly increased with age in both groups. 4. Three subgroups divided by Angle's classification did not show any difference in occlusal wear area among them, but three subgroups divided by lateral guidance pattern showed slightly significant difference between canine guide subgroup and group function subgroup in patients. Occlusal wear ares\a in group function subgroup wear larger than canine guide subgroup. 5. Mean value of wear area in patients with bruxing and/or clenching habit did not differ from those in patients without such habit. 6. Correlationship among items related to occlusal contact pattern were highly consistent and significant in dental students and only one item significantly correlated with occlusal wear area was tooth contact time.

• Journal of Dental Rehabilitation and Applied Science
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• v.21 no.1
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• pp.43-57
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• 2005

Temporomandibular disorders have been defined as a collective term embracing a number of clinical problems that involve the temporomandibular joint, the masticatory nuscles, and associated structures. There have been many different contributing factors of TMDs which were traumatic, occlusal, pathophysiological and psychosocial. Among there factors, the effect of occlusion on TMDs have been a controversy for a long time. The purpose of this study was to investigate the effect of occlusal factors and oral habits on TMDs. In this study, 140 subjects with signs and symptoms of TMDs and diagnosed of TMD in the Orofacial Pain clinic of Yonsei University Dental Hospital though March to July 2004 were selected for the TMDs group and 50 subjects without any signs and symptoms of TMDs as the control group. The subjects were evaluated clinically in TMDs' Occlusal and Prosthodontic Restoration examinations. TMDs' examination was composed of the TMJ pain, sound, locking, temporal or masseter muscle palpation, mandibular movement, oral habits and headache. Occlusal examination was made of overjet, overbite, lost teeth number, nonfunctional interference, midline shift, then pattern of lateral movement and attrition. prosthodontic restoration examination had the existence of restoration, placement, then number of crown or bridge and Satisfiable index which estimated the quality of occlusal state of prosthodontic restorations. Following results were obtained : 1. The prevalence of TMDs was higher in their 20s & 30s, female of the TMD patients group. 2. The clenching frequency in the TMDs group(40.71%) was higher than those in the control group(18.00%), and there was a significant statistical difference(p<0.05). 3. The frequency of Nonfunctional interference in the TMDs group(10.00%) was higher than those in then Control group(2.00%), and there was a significant statistical difference(p<0.05). The result of this study indicated TMDs prevalence was higher in their 20s, 30s, female group of TMDs patients similar to the previous studies. Clenching and nonfunctional interference were estimated as the contributing factors of TMDs.

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

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.181-192
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• 1994

There have been many different theories on the etiology of temporomandibular disorders(TMDs). The objective of the study was to investigate the effects of occlusal fctors and recent life event changes as prediposing fctor on the development of temporomandibjlar disorders. To evaluate the above predisposing factor, the author used T-scan system(Tekscan Co. U.S.A.) for quantitative occlusal analysis, clinical examination for occlusal state and Social Readjustment Rating Scale(SRRS) for recent life event change units (LCU). 63 patients with TMDs and 57 patients with malocclusion presented at Wonkwang University Dental Hospital participated in this study. The subjects were grouped by Angle's classification and presence of absence of TMDs and parafunctional oral habits. Data gained with regard to contact number, contact force, contact time, occlusal state(number of total teeth and occluding teeth, overjet, overbite) and occlusal interferences (protrusive posterior contact, nonworking side interference, and RCP-ICP slide) and recent life event changes. The data were processed and analysed by SAS statistical package program, The results of this study were as follows : 1. There were no significant differences on both quantitative occlusal contact analysis and occlusal state between TMDs group and Angle's malocclusion group. Also, there were no differences among the Angle's classifications. But amount of overjet in TMDs group were more greater than that of malocclusion group. 2. There was no difference on protrusive posterior contact, and balancing contact between TMDs group and Angle's malocclusion group. Premature contact was more frequent in malocclusion group, but RCP-ICP slide was more frequent in TMDs group. And RCP-ICP slide was more freqent in Angle's class II malocclusion than Angle's I or III malocclusion. 3. Life changes units in TMDs group were higher than those in malocclusion group. And recent life change units in group with parafunctional oral habit were higher than those in group without parafunctional oral habits. Clenching was the most common habit among parafunctional oral habits.

• Journal of The Korean Dental Society of Anesthesiology
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• v.10 no.1
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• pp.13-19
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• 2010

Bruxism is nonfunctional jaw movement that includes clenching, grinding and gnashing of teeth. It usually occurs during sleep, but with functional abnormality of brain, it can be seen during consciousness. Oromandibular dystonia (OMD) can involve the masticatory, lower facial, and tongue muscles and may result in trismus, bruxism, involuntary jaw opening or closure, and involuntary tongue movement. Its prevalence in the general population is 21%, but its incidence after brain injury is unknown, Untreated, bruxism and OMD cause masseter hypertrophy, headache, temporomandibular joint destruction and total dental wear. We report a case of successful treatment of bruxism and OMD after brain injury treated with botulinum toxin A and occlusal appliance. The patient was a 59-year-old man with operation history of frontal craniotomy and removal of malformed vessel secondary to cerebral arteriovenous malfomation. We injected with a total 60 units of botulinum toxin A each masseteric muscle and took impression for occlusal appliance fabrication under general anesthesia. On follow up 2 weeks and 2 months, the patient remained almost free of bruxism. We propose that botulinum toxin A and occlusal appliances be considered as a treatment for bruxism and OMD after brain injury.