• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.837-842
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• 1998

Rett syndrome is a progressive neurological disorder that occurs exclusively in females. The syndrome is characterized by regression of language, motor development, and stereotypic hand movement. Autistic behavior, breathing irregularities, gait dyspraxia, scoliosis, and seizure are also accompanied. The cause of Rett syndrome is unknown, however, it is believed that the X-chromosome might playa significant role in the development of the syndrome. Patients with this syndrome have unusual oral and/or digital habits such as abnormal chewing pattern, bruxism, hypersalivation, micrognathia, high vaulted palate, tongue protrusion with lower posture of tongue, hand biting, digit-hand sucking. Dentists who are aware of distinct manifestations of Rett syndrome will be able to aid in early diagnosis and treatment of the syndrome. Prior to dental treatment for a patient with the Rett syndrome under sedation or general anesthesia, one should assess the degree of hypersalivation, apnea, severity of autism, expected life span. Early recognition of the syndrome and also dental treatment with established strict preventive guidelines for patients with the Rett syndrome may obviate the necessity of sedation or general anesthesia. Two cases with the Rett syndome were reported. Both patients had most of the above mentioned typical manifestations of the syndrome. Dental treatment for the case 1(8-year-old) including caries control, stainless steel crown, sealant application was performed under general anesthesia. The case 2 could not be undergone the dental treatment due to poor general conditions.

• Journal of Oral Medicine and Pain
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• v.31 no.1
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• pp.101-111
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• 2006

Temporomandibular disorders (TMD) is a collective term embrassing a number of clinical problems that involve the masticatory musculature, the Temporomandibular joint and associated structures, or both. The prevalence of signs and symptoms associated with TMD can be best appreciated by examining epidemiologic studies. But domestic epidemiologic studies about sex, history, chief complaint, diagnosis were not sufficient comparing with foreign countries. The results obtained as follow. 1. The number of visiting patients were 6500 and mean age was 34.06 year (Male's mean age was 33.15, Female's 34.62). In the age of patients, there was no significant difference between sex. 2. There are most patients who were referred by dentist (80.07%). Most diagnostic group was arthrogenous TMD group and followed by myogenous TMD, soft tissue disease. 3. There was strong interaction between diagnostic groups and chief complaint. 4. There was little pain difference between right and left sides. Male mainly had pain onset under 6 month, but female had pain onset more than 6 month. 5. The number of patients who had joint sound history were 3445 (53.15%). There was no significant difference of pain onset between sex. Clicking sound was most among joint sounds which happened to patients. 6. In analyzing the parafunctional habit, male mainly had bruxism, but female had clenching habit.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.225-231
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• 2021

There are many studies on the indications and efficacy of splint therapy commonly used in patients with temporomandibular disorders (TMD). However, there have been no studies on the splint weaning in terms of the splint use tapering period in relation to symptom improvement of TMD. This retrospective study aims to analyze a proper splint weaning method in patients with TMD based on symptom improvement. Materials and Methods: The authors examined 130 TMD patients with TMJ disorders, masticatory muscle disorders, and clenching/bruxism who had received splint therapy (occlusion stabilization splint, anterior positioning splint) of patients who visited the Department of Orofacial Pain and Oral Medicine at Yonsei University Dental Hospital from 2015 to 2020. They were evaluated according to the method to wean splints. Results: The mean splint therapy period was 29.0 months, during which patients wore splints 7 days a week for 8.4 months, 3 - 4 days a week for 9.5 months, and finally 1 - 2 days a week for 11.1 months (a total of 29.0 months, about 2.5 years). Conclusion: It seems that TMD symptoms can be alleviated and side effects such as occlusal change can be minimized if patients wear a splint 7 days a week for the first 6 months, followed by 3 - 4 days a week for the next 6 to 18 months, and finally 1 - 2 days a week after 18 months.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.227-233
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• 2023

Tardive dyskinesia is an involuntary neurological movement disorder caused by long-term use of dopamine receptor-blocking drugs leading to dental implications like uncontrolled gnashing and grinding of teeth which in turn imperil the oral rehabilitation procedures as the excessive load increases the risk of prosthesis fracture. A 40-year male with a medical history of tardive dyskinesia visited the hospital to receive oral rehabilitation for missing maxillary anterior teeth. After the oral examination, tooth preparation was done on teeth 13, 15, and 23. After that silicon impression was made and the gypsum cast was digitalized using a desktop scanner and an interim prosthesis was fabricated by milling a resin block. During the try-in, the occlusal one-third of the interim prosthesis was trimmed, and an auto-polymerizing acrylic resin was applied on the occlusal surfaces and inserted in the patient's mouth. Then, the functionally generated path (FGP) of occluding surfaces of opposing arches was traced on the resin surface. When the resin was hardened, the modified interim prosthesis was removed and digitized using an intraoral scanner. The scan image was used in designing the occlusal morphology of definitive prosthesis by modifying the design of the interim prosthesis using the dual scan method. Lastly, a monolithic zirconia prosthesis was fabricated by milling a zirconia block. The definitive prosthesis was delivered reflecting the patient's occlusal scheme. This case report shows that the FGP technique with the dual scan method can help in fabricating fixed prosthesis with harmonious occlusion in a tardive dyskinesia patient.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.215-226
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• 2023

Severe wear of the anterior teeth facilitates the loss of anterior guidance, which protects the posterior teeth from wear during excursive movement. Additionally, when treating patients with collapsed occlusion due to multiple tooth loss and tooth wear, it is important to determine the presence of vertical dimension loss through accurate clinical and radiographic examinations and diagnostic wax-up. The patient of this case is a 44-year-old female patient who complained of overall tooth wear and loss of posterior teeth due to bruxism and clenching habits, visited the hospital with the address of restoring masticatory function and improving aesthetic appearance through prosthetic treatment. Through model analysis and diagnostic wax-up, an increase in vertical dimension was determined, and full mouth restoration with fixed prostheses was planned. The degree of adaptation to the vertical dimension was confirmed step by step using an occlusal splint designed with CAD (Computer aided design) software and 3-D (3-Dimensional) printed, and then restored with provisional restoration and after a 4-month adaptation period, the entire dentition was restored with metal ceramic crowns and implants. Through this procedure, satisfactory treatment results were obtained in terms of function and aesthetics.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.113-122
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• 2024

The gradual teeth wear with age is a natural phenomenon, but excessive wear beyond physiological levels can lead to vertical dimension loss, occlusal imbalance, temporomandibular joint disorders, and periodontal disease. In such cases, prosthodontic restoration becomes necessary emphasizing the importance of appropriate vertical dimension increase and stable occlusion in central relation (CR). In this case, a 74-year-old patient with clenching and grinding habit had severe teeth wear and after assessing interocclusal distance, wear degree, pronunciation, and facial profile, it was decided to perform full-mouth fixed prosthesis restoration with a 4 mm vertical dimension increase. And the significantly displaced Maximum Intercuspal Position (MICP) caused by parafunctional movements was re-established as a stable mutually protective occlusal relationship at centric relation and after a successful 4 months adaptation to provisional restorations, the final prosthesis was fabricated. During 4months of observation periods, stable occlusion in central relation and mutual protection occlusal relationships were maintained and the patient was satisfied with function and aesthetics, leading to this report.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.411-426
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• 2005

The purpose of this study was to investigate the effects of occlusal condition and clenching level on the mandibular torque rotational movement. For this study, healthy 14 men without any symptoms and signs of temporomandibular disorders were selected. Mandibular torque rotational movement was observed in each circumstance of combination of three occlusal conditions such as natural dentition, with wafer of 3.6 mm thickness, and wafer with resin stop of 14 mm thickness total during hard biting of bite stick at maximum voluntary contraction(MVC) and 50% of MVC level of surface EMG activity of masseter muscle. Electromyographic activity and mandibular torque rotational movement were observed using BioEMG and BioEGN in $BioPak^{(R)}$ system. Each biting movement in each circumstance was composed of clenching one time and hard biting of wooden stick two times. The observed items were opening distance, velocity and amount of torque rotational movement in mandibular movement, and the data were statistically processed with $SPSS^{(R)}$ windows (ver.10.0). The results of this study were as follows: 1. There were no differences in the mandibular movement distance between those value in both biting sides, and between those in both clenching forces, but the mandibular velocity showed a different results by clenching force. For the amount of torque rotational movement, there were no difference in the value of the frontal plane but some significant difference was in the value of the horizontal plane by biting side. 2. The mandibular movement distance and the mandibular velocity in both planes were higher by maximum voluntary contraction than those by half maximum voluntary contraction, and amount of torque rotational movement in the horizontal plane was also increased by maximum voluntary contraction. 3. The opening distance in both planes were decreased with the increase of vertical dimension of occlusion, namely, by the occlusal appliances, and this pattern was also showed in the mandibular velocity in case of hard biting by maximum voluntary contraction. However, the amount of torque rotational movement were not different by the increase of vertical dimension of occlusion. 4. The value of angle and distance of the torque rotational movement in the hard biting of wooden stick were generally higher than those in the clenching without wooden stick in both planes without regard to occlusal conditions and/or clenching forces.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.61-73
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• 2010

The aim of this study was to investigate clinical assessment and cephalometric characteristics in 10s patients with condylar resorption, who visited in the Department of Oral Medicine Kyungpook National University Hospital at 2006, by use of panorama, transcranial view and lateral cephalometric radiograph. The results were as follows; 1. Clinical assessment 1) Total number of patients were 59. Female was 47 and male was 12, Females were predominant and patient's age ranged from 12 to 19. 2) Most of the patients had Grade II condyle resorption. 3) The number of who had Class I occlusion was 27, which was the largest group. The number of patients with openbite was 20. Average overjet was 3.58mm and average overbite was 0.97mm. 4) Most of the patients had parafunctional habit. 5) The patients of showing the pain in condylar resortion was 41 and the case of not showing the pain was 18. 6) Treatment duration of 23 patients were less than 1 month, 28 patients were treated with supported therapy. 2. Cephalometric Characteristics 1) A 16-year-old female patients showed smaller SNA, SNB and larger articular angle significantly as compared with those of normal group. 2) A 17-year-old female patients showed smaller SN, SAr, TPFH, ramus height and larger SN-GoMe, FMA, articular angle significantly as compared with those of normal group. 3) Over 18 years old female patients showed smaller SN, SNB, TPFH, ramus height and larger ANB, FMA, SN-GoMe, LAFH, articular angle, gonial angle significantly as compared with those of normal group. 4) Over 18 years old male patients showed smaller SN, TPFH, ramus height and larger FMA, SN-GoMe, LAFH, articular angle, gonial angle significantly as compared with those of normal group. 5) There was no significant difference between 10s and normal group in mandibular body length.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.75-81
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• 2010

By repeating nocturnal bruxism occlusal appliance's wearing condition that is used to cure temporomandibular disorders into the vitro experiment, research aims to find out how moisture infiltrated and drying cycle process affects on the surface microhardness of the resin for occlusal appliance and flexural strength. By utilizing resin for occlusal appliance which is the main component of poly methyl methacrylate, bar shaped sample was produced. For the resin sample utilized as the controlled group 1, the sample was infiltrated in the moisture for 7 days in the temperature of 37C. Then, the resin sample of the controlled group 2 was maintained in a dry condition for 7 days in the normal temperature. After that, each sample's surface microhardness and flexural strength were measured. For the resin sample that is utilized as the experimental sample, the sample was infiltrated in the moisture for 7 days in the temperature of 37C. Then, it was inundated for 8 hours a day and dried in the normal temperature for 16 hours with the continuous process of moisture infiltration and dry cycle process for 30 days. During this cycle process, sample's surface and flexural strength were measured in the 1st day, 7th day, and 30th day. Then, it was statistically analyzed to find out the difference of controlled and experiment group's surface microhardness and flexural strength. Results are 1. For the experimental and controlled group's surface microhardness of the resin for the occlusal appliance, it did not show any significant differences after moisture infiltration and dry cycle process repetition. 2. In case of the flexural strength for resin for the occlusal appliance, experimental group with moisture infiltration and dry cycle for 30 day process had greater effect than the experimental group at the 1st day and controlled group These results can be considered to be utilized from the patients of the temporomandibular disorders towards occlusal appliance used and maintained method.

• Journal of Oral Medicine and Pain
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• v.33 no.1
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• pp.85-95
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• 2008

The purpose of this study was to evaluate the effects of oral habits on the muscles of mastication and facial expression by means of two parameters: muscle stiffness and elasticity. 10 healthy, fully-dentate male subjects in their twenties were selected for this study; all had normal Class I occlusal relationships. Muscle stiffness and elasticity were measured with a tactile sensor(Venustron, Axiom Co., JAPAN) while subjects were asked to relax and perform various parafunctional activities such unilateral clenching(biting the bite force recorder with a force of 50kg on each subject's preferred side), jaw thrusting and lip bracing. The following muscles were examined: temporalis anterior(Ta), masseter(Mm), frontalis(Fr), inferior orbicularis oculi(OOci), zygomaticus major(Zm), superior and inferior orbularis oris(OOrs and OOri) and mentalis(Mn). Paired t-test, Correlation Coefficients, ANOVA and Multiple Comparison t-tests were used for statistical analysis. Unilateral clenching was highly correlated with bilateral stiffness and elasticity of all the muscles tested. Mm was affected by all three oral habits; Ta was affected by unilateral clenching(p<0.05); Zm was affected by unilateral clenching and OOrs, OOri and Mn were most affected by lip bracing(p<0.05). This study indicates that not only the masticatory muscles but also the muscles of facial expression, mainly circumoral muscles, can be significantly influenced by parafunctional activities such as unilateral clenching and lip bracing.