• Biomedical Science Letters
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• v.29 no.3
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• pp.168-177
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• 2023

Recently, as a health problem of the elderly in an aging society, the risk of nutritional imbalance and weakening of immunity due to deterioration of masticatory function has been mentioned. In order to solve this problem, this study was conducted to investigate the effect of cyclophosphamide (CPA)-induced immunosuppression in mice induced by fermented samultang (FST) porridge on the markers related to immune activity function. ICR Mouse was divided into 6 groups of 7 animals each. Experimental groups were set as normal control group, CPA-administration group, positive control group, and FST-administration experimental group (0.25%, 0.5%, 1.0%). In groups except for the normal control group, 100 µL of CPA dissolved in 0.9% NaCl at a concentration of 150 mg/kg was injected twice at the start of the experiment and after 3 days to induce immunosuppression. As a result of analyzing the cell proliferation capacity of splenocytes, all B and T cells decreased in the CPA-administered group and increased in a concentration-dependent manner in the FST-administered group. In addition, IgA measured to evaluate the effect of improving immunity showed high values in medium and high concentration FST (P<0.05). These results can be expected as an effective solution to improve the nutritional imbalance of the elderly.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.3
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• pp.247-256
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• 2003

The patient had bruxism and epilepsy tendency. Inadequate or unstable posterior support was identified due to severe anterior attrition and decreased occlusal vertical dimension. Prematurities of posterior occlusal and wear facets increased the function of anterior teeth, resulting in severe wear. Wear facets displayed sharply defined peripheries, which are matched on articulated diagnostic casts. Also the patient showed C III malocclusion tendency, and lost some facial contour with drooping corners on the mouth. In this case, the alteration of OVD (Occlusal Vertical Dimention) may provide a biologically compatible adjunct to the treatment such as dentofacial esthetics, improved visual proportion in facial heightand mechanical solutions to the force-management of the masticatory system. The patient requires extensive restorative treatment to regain appropriate function, esthetics and comfort. According to the report by Farhad Fays, the average vertical distance from the maxillary to the mandibular mucolabial reflection in the region of the central incisors is approximately 34mm. However, the vertical distance of this patient was found to be 32mm, which was necessary to add gauge 20-sheets to apply vertical dimension. A removable occlusal overlay splint, which restores OVD to the estimated optimalposition, is the general first trial. The patient was observed periodically for 6 weeks, while appropriate adjustments were made vertical dimension to function. When patient felt comfortable with the splint, the teeth were prepared, and provisional restorations are placed for 3 months. The provisional restoration was fabricated by a diagnostic wax-up. When the patient felt comfortable with the provisional restoration, the final restoration mimics OVD, function, and esthetics that have been developed in the treatment restorations. Restoration of the extremely worn dentition presents a substantial challenge to thedentists. Therefore, careful evaluation of the etiology, history, and factors associated with occlusal vertical dimension should be preceded prior to the appropriate treatment planning.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.3
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• pp.145-154
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• 2001

In the past, many dentist were interested mainly in the mechanical aspects such as tooth preparation and retainer types for making dental restoration. But, these days, the concept of restorative treatment emphasizes the importarce of gnatic system and masticatory muscles in addition to oral cavity. So, the current considerations for the fixed prosthodontic treatment include the stabilization of temporomandibular joint and neuromuscualr system and the relationship of periodontal ligament and occlusion. To achieve the above objectives, occlusal splint has been used as one of the mouth preparations for restorative treatment. The objectives of occlusal splint are as follows; 1. To use as preliminary application for periodontal-occlusal treatment 2. To provide proper vertical dimension 3. To control abnormal habits and parafunction 4. To treat the temporomandibular disease and myofascial pain 5. To establish the new therapeutic position In some cases, the patients had improper vertical dimension and occlusal interferences caused by prostheses reconstucted using centric relation recorded without considering the health of TMJ and manticatory muscle. And these prosthesis act as primary source that cause pathologic phenomenon in periodontal ligament, muscles and TMJ. Physiologically, in order to make the treatment occlusion guided by proper centric relation method, the method should be guided after the use of occlusal splint for some period. The main objective of prosthetic treatment is to maintain the function and health of stomatognathic system. So, one of the most important things that have to be performed by clinicians is a clinical ability to do the correct diagnosis and treatment planning based on the stomatognatic function and occlusion.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.245-256
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• 2001

The purpose of this study is to analyze the mechanical stress and displacement on the jaws during the simulated bilateral clenching task on the three-dimensional finite element model of the dentated skull with unilateral molar loss. For this study, the computed tomography(G.E.8800 Quick, USA) was used to scan the total length of human skull in the frontal plane at 2.0mm intervals. The fully assembled finite element model consists of the articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. The FE model was used to simulate the bilateral clenching in intercuspal position. The loading condition was the force of the masseter muscle exerted on the mandible as reported by Korioth et al. degrees of freedom of the zygomatic region where the masseter muscle is attached were fixed as restraints. In order to reflect the actual action of the muscles force, the displacement of the region was attached where the muscle is connected to the temporal bone and restraint conditions were given values identical to values at the attachment region of the masticatory muscle but with the opposite direction of the reaction from when the muscle force is acted on the mandible. Although the mandible generally has higher displacement and von Mises stress than the maxilla, its mandibular corpus on the molar-loss side has a higher stress and displacement than the molar-presence side. Because the displacement and von Mises Stress was the highest on the lateral surface of mandibular corpus with molar loss, the stress level of the condyle on the molar-loss side is greater than that of the molar-presence side, which in turn caused the symphysis of the mandible to bend. In conclusion, the unilateral posterior bite collapse with molar loss under para-functional activities such as bruxism and clenching can affect the stress concentration on the condyle and mandibular corpus. It is therefore necessary to consider the biomechanical function of dento-skeleton under masticatory force while designing the occlusal scheme of restoration on alveolar bone with the posterior collapse.

• The Journal of the Korean dental association
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• v.54 no.4
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• pp.296-305
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• 2016

Narrow zone of attached gingiva and shallow vestibule around the implants might contribute to difficulty of cleasing, periimplant mucositis caused by incomplete cleansing and further peri-implantitis. The aim of this case report is to present modification of soft tissue biotype around the implants by free gingival grafts according to timing of surgical intervention and shape of free gingiva. A 44 year-old male patient had a missing area on lower right second molar area with 1 to 2 mm of narrow attached gingiva zone and wanted to be treated by implant placement. In radiographic analysis, there was enough alveolar bone to install an implant, free gingiva from hard palate was grafted following implant placement using double layer flap. The width of attached gingival was increased to 4 to 5mm and well maintained during 5 months of follow up. A 69 year-old female patient also had a missing area on lower right first and second molar area with 1 to 2 mm narrow attached gingiva. Since she had systematically angina pectoris and dental phobia, minimal invasive free gingival graft after implants placement was planned. After 2 months of implant surgery, free gingival graft surgery was performed with healing abutments connection. The grafted gingiva was composed of two strip shaped free gingiva, and they were immobilized by periodontal pack. The width of attached gingival was increased to 4 to 5mm and well maintained during 10 months of follow up. With prosthesis delivery, the patients recovered ideal periodontal environment around implants and masticatory function. In conclusion, periodontal health and masticatory function could be achieved through implant placement and free gingival graft.

• Journal of Korean Dental Science
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• v.16 no.2
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• pp.128-148
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• 2023

Dementia is an umbrella term that describes the loss of thinking, memory, attention, logical reasoning, and other mental abilities to the extent that it interferes with the activities of daily living. More than 50 million individuals worldwide live with dementia, which is expected to increase to 131 million by 2050. Recent research has shown that poor oral health increases the risk of dementia, while oral health declines with cognitive decline. In this narrative review, the literature was based on the "hypothesis" that dementia and oral health have a close relationship, and appropriate oral health and occlusal rehabilitation treatment can improve the quality of life of patients with dementia and prevent progression. We conducted a literature search in PubMed and Google Scholar databases, using the search terms "dementia," "major neurocognitive disorder," "dentition," "occlusion," "tooth loss," "dental prosthesis," "dental implant," and "occlusal rehabilitation" in the title field over the past 30 years. A total of 131 studies that scientifically addressed dementia, oral health, and/or oral rehabilitation were included. In a meta-analysis, the random effect model demonstrated significant tooth loss increasing the dementia risk 3.64-fold (pooled odds ratio=3.64, 95% confidence interval [2.50~5.32], P-value=0.0348). Tooth loss can be an important indicator of cognitive function decline. As the number of missing teeth increases, the risk of dementia increases. Loss of teeth can lead to a decrease in the ascending information to the brain and reduced masticatory ability, cerebral blood flow, and psychological atrophy. Oral microbiome dysbiosis and migration of key bacterial species to the brain can also cause dementia. Additionally, inflammation in the oral cavity affects the inflammatory response of the brain and the complete body. Conversely, proper oral hygiene management, the placement of dental implants or prostheses to replace lost teeth, and the restoration of masticatory function can inhibit symptom progression in patients with dementia. Therefore, improving oral health can prevent dementia progression and improve the quality of life of patients.

• 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.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.456-467
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• 2009

For this study, self-completion survey for 149 implant patients of dental clinics and hospitals in Seoul and Kyunggi areahas been executed in order to provide basic data for increasing patient satisfaction level by effective consultation and various information for the patients who want dental implantation. The conclusion of the study is like below. 1. In terms of demographics of the study, sample size of female patients(n=85) was more than that of male patients(n=64) and patients in their 50s were major age group. When it comes to the educational level, university graduates were 85 and high school graduates were 44. And 132 were married and 6 were single. In the income level, monthly income between KRW 2~4 million was major group(n=59). 2. In the study, patients' most concern was complication or adverse events(n=41), and price(n=39) & annual dental check-up(n=49) were following it. And 80 patients responded that dental health is the most valuable(n=80) and whole body health was following(n=37). In terms of knowledge on dental implant, 100 patients responded 'know just a little', 31 and 13 answered 'generally know' and 'well know' each. 3. As a result of analyzing implant patients' satisfaction level by segment, general satisfaction rate was highest as 4.20, social satisfaction rate was 4.20, psychological function was 4.06 and masticatory function was 3.90. 4. Based on the result of comparing patient satisfaction level by general characters of dental implant patient, chewing function was the highest in the age group of 60s with score of 4.21 and in terms of social function, the group with over KRW 8 million of monthly income showed highest score with 4.54. When it comes to the psychological function, patients in their 70s showed highest satisfaction level with 4.52. In the end, patients in their 70s showed highest score with 4.81 in the overall satisfaction and it was also statistically significant. 5. In the overall satisfaction level by interest in dental health, appearance showed highest score with 4.57 and it was also significantly higher than that of whole body. In the variance by dental knowledge, 'well know' group showed highest score with 4.58, and that of 'just a little' group was 4.33. That means there are correlations between dental knowledge and satisfaction level. 6. As a result of analyzing correlations amongst variances of the study, there were strong positive correlations among them. And there were very significantly positive correlations especially between social and psychological function and between psychological and overall satisfaction level. In conclusion, higher psychological function has strong relations with both social function and overall satisfaction level(p<.001).

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.322-329
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• 2016

Reconstruction of the maxillectomy with an obturator is to restore masticatory, swallowing, phonetic and esthetic problems. Stress created by lateral forces is minimized by the proper selection of an occlusal scheme, elimination of premature occlusal contacts, and wide distribution of supporting area. It should be considered that properly designed retainers reduce the stresses transmitted to the abutment while the obturator is in function. The following clinical report presents palatal obturator treatment with implant assisted removable partial denture (IARPD) design that restores normal function and esthetics in patients who experienced maxillectomy and dental implant failure.

• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.1-12
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• 2020

Pierre Robin syndrome is characterized by micrognathia, glossoptosis, and cleft palate. Infants with Pierre Robin syndrome causes feeding difficulty, upper airway obstruction, and other symptoms. This study aims to examine the effects of applying dysphagia treatment to infants with Pierre Robin syndrome. The study participant was an infant who was born four weeks premature and referred for dysphagia treatment approximately 100 days after birth. At the initial assessment, the infant showed oral sensory sensitivity, a high level of facial and masticatory muscle tension, and a low stability of the chin and cheeks with almost no normal "sucking-swallowing-breathing" pattern. We set the baseline period and intervention period using the AB design. During the baseline period, non-nutritive sucking training using a rubber nipple was conducted without implementing an oral stimulation intervention. During the intervention period, non-nutritive sucking training and an oral stimulation intervention were performed. After the intervention period, the infant's daily oral intake and oral intake per time significantly increased compared to that during the baseline period. We observed that the oral intake time of the infant decreased during the intervention period compared to that in the baseline period, which indicated an improvement in control over the chin, tongue, and lip movements, a change in muscular tension, and stabilization of the "sucking-swallowing-breathing" pattern. We provided dysphagia treatment before breastfeeding, it was positive effects such as normal development of the infant, transition from tube feeding to bottle feeding, and enhancement of overall oral motor function.