• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.507-516
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• 1995

The nonstationary identifier in the DCT domain is suggested in this study for the identification of AR parameters of above-lesion upper-trunk electromyographic (EMG) signals as a means of developing a reliable real time signal to control functional electrical stimulation (FES) in paraplegics to enable primitive walking. As paraplegic shifts his posture from one attitude to another, there is transition period where the signal is clearly nonstationary. Also as muscle fatigues, nonstationarities become more prevalent even during stable postures. So, it requires a develpment of time varying nonstationary EMG signal identifier. In this paper, time varying nonstationary EMG signals are transformed into DCT domain and the transformed EMG signals are modeled and analyzed in the transform domain. In the DCT domain, we verified reduction of condition number and increment of the smallest eigenvalue of input correlation matrix that influences numerical properties and mean square error were compared with SLS algorithm, and the proposed algorithm is implemented using IMS T-805 parallel processing computer for real time application.

• Journal of Oral Medicine and Pain
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• v.33 no.4
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• pp.317-322
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• 2008

The moderners of industrial society suffer from various stresses, which bring about increase in prevalence of temporomandibular disorders, oral mucosal disease and chronic neuropathic pain, therefore, the number of patients seeking help of those symptoms tend to increase. The purpose of this study was to discuss the importance of oral medicine related disease by investigating questions that appeared in cyber consultation of Kangnung National University Dental Hospital web site. Among the nearly 2000 questions, the rate of questions related to oral medicine was 20.92%, and the rate of questions related to other departments were oral and maxillofacial surgery 16.87%, conservative dentistry 16.67%, orthodontics 14.02%, prosthodontics 12.25%, periodontics 8.36%, pediatric dentistry 4.93%, preventive dentistry 2.08% and otherwise questions 3.90%. Among the 403 questions related to oral medicine, the frequent questions were oral mucosal diseases 44.17%, temporomandibular disorders 41.19%, halitosis 4.47%, xerostomia 3.23%, other orofacial pain 2.23%, forensic dentistry 1.49% and otherwise questions 2.98%. From the higher rate of questions related to oral medicine compared with other fields of dentistry, we would consider that the people are considerably concerned about the oral medicine related disease, such as oral mucosal diseases and temporomandibular disorders.

• Journal of Periodontal and Implant Science
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• v.28 no.1
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• pp.1-16
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• 1998

자연치의 경우에는 치주지수간의 상관관계가 정립되어 병적인 상태에 대한 진단과 그에 따른 치료방법을 결정하는데 많은 정보를 제공하나, 인공매식치에서는 아직 논란의 여지가 많다. 이에 임상적으로 안정화되어 기능하고 있는 인공매식치에서 치주지수간의 상관관계에 관하여 연구하고자 하였다. 총 43명의 환자(평균 44.7세)에 식립된 178개의 인공매식치를 연구에 이용하였다. 인공치아매식술을 시행한 후 1년에서 6년이 경과한 인공매식치에서 상부보철물을 제거한 후 치태지수, 치은열구출혈지수, 각화점막지수, 치주낭깊이, Periotest Values(PTVs) 등을 측정하여 각각의 분포상황과 상관관계를 분석하였다. 이 연구의 결과는 다음과 같다. 1. 치태지수의 평균값은 $0.83{\pm}0.82$이었다. 2. 치은열구출혈지수의 평균값은 $1.04{\pm}0.86$이었다. 3. 각화점막지수의 평균값은 $2.47{\pm}0.95$이었다. 4. 치주낭깊이의 평균값은 $3.12{\pm}1.14\;mm$이었다. 5. Periotest Values(PTVs)의 평균값은 $-0.66{\pm}4.28$이었다. 6. 치태지수, 치주낭깊이가 증가함에 따라 치은열구출혈지수는 유의성있게 증가하였다(P<0.01). 7. 각화점막지수가 증가함에 따라 치은열구출혈지수는 유의성있게 감소하였다(P<0.01). 8. 치은열구출혈지수와 매식치동요도 사이에서는 유의성있는 상관관계를 발견할 수 없었다(P>0.05). 9. 치주낭깊이와 매식치동요도 사이에서도 유의성있는 상관관계를 발견할 수 없었다(P>0.05). 10. 인공매식치의 직경과 길이가 증가함에 따라 매식치동요도는 유의성있게 감소하였다(P<0.01). 11. 하악에서의 매식치동요도가 상악의 경우와 비교하여 유의성있게 작았다(P<0.01). 결론적으로, 인공매식치에서도 자연치에서와 동일한 양상으로 치태가 많을수록, 그리고 치주낭 깊이가 깊을수록 염증의 심도와 관련이 깊은 것으로 생각된다. 특히, 인공매식치의 경우에는 같은 양의 치태가 존재시에 각화치은이 충분히 있는 쪽이 염증발생이 적은 것으로 나타났다. 치주조직에 염증이 존재하는 경우, 자연치아에서는 치아의 동요도가 증가하는 것으로 알려져있으나, 이 실험의 인공매식치에서는 유의성있는 상관관계를 발견할 수 없었다. 임상적으로 안정화된 인공매식치의 동요도는 염증정도에는 큰 영향을 받지 않고 인공매식치의 직경과 길이가 증가함에 따라 감소함을 보여주고 있다. 또한, 인공매식치의 동요도는 상하악골의 골질에 따라 차이가 있음을 명확히 보여주고 있다.

• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.14-21
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• 2014

PURPOSE. The purpose of this study was to evaluate bone response to anodized titanium implants coated with the extract of black cohosh, Asarum Sieboldii, and pharbitis semen. MATERIALS AND METHODS. Forty anodized titanium implants were prepared as follows: group 1 was for control; group 2 were implants soaked in a solution containing triterpenoids extracted from black cohosh for 24 hours; group 3 were implants soaked in a solution containing extracts of black cohosh and Asarum Sieboldii for 24 hours; group 4 were implants soaked in a solution containing extracts of pharbitis semen for 24 hours. The implants from these groups were randomly and surgically implanted into the tibiae of ten rabbits. After 1, 2, and 4 weeks of healing, the nondecalcified ground sections were subjected to histological observation, and the percentage of bone-to-implant contact (BIC%) was calculated. RESULTS. All groups exhibited good bone healing with the bone tissue in direct contact with the surface of the implant. Group 2 ($52.44{\pm}10.98$, $25.54{\pm}5.56$) showed a significantly greater BIC% compared to that of group 3 ($45.34{\pm}5.00$, $22.24{\pm}2.20$) with respect to the four consecutive threads and total length, respectively. The BIC% of group 1 ($25.22{\pm}6.00$) was significantly greater than that of group 3 ($22.24{\pm}2.20$) only for total length. CONCLUSION. This study did not show any remarkable effects of the extract of black coshosh and the other natural products on osseointegration of anodized titanium implants as coating agents. Further studies about the application method of the natural products on to the surface of implants are required.

• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.1-7
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• 2014

PURPOSE. The accuracy of a gypsum model (GM), which was taken using a conventional silicone impression technique, was compared with that of a polyurethane model (PM), which was taken using an iTero$^{TM}$ digital impression system. MATERIALS AND METHODS. The maxillary first molar artificial tooth was selected as the reference tooth. The GMs were fabricated through a silicone impression of a reference tooth, and PMs were fabricated by a digital impression (n=9, in each group). The reference tooth and experimental models were scanned using a 3 shape convince$^{TM}$ scan system. Each GM and PM image was superimposed on the registered reference model (RM) and 2D images were obtained. The discrepancies of the points registered on the superimposed images were measured and defined as GM-RM group and PM-RM group. Statistical analysis was performed using a Student's T-test (${\alpha}=0.05$). RESULTS. A comparison of the absolute value of the discrepancy revealed a significant difference between the two groups only at the occlusal surface. The GM group showed a smaller mean discrepancy than the PM group. Significant differences in the GM-RM group and PM-RM group were observed in the margins (point a and f), mesial mid-axial wall (point b) and occlusal surfaces (point c and d). CONCLUSION. Under the conditions examined, the digitally fabricated polyurethane model showed a tendency for a reduced size in the margin than the reference tooth. The conventional gypsum model showed a smaller discrepancy on the occlusal surface than the polyurethane model.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.233-240
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• 2014

PURPOSE. To evaluate the effects of different abutment geometries in combination with varying luting agents and the effectiveness of different cleaning methods (prior to re-cementation) regarding the retentiveness of zirconia copings on implants. MATERIALS AND METHODS. Implants were embedded in resin blocks. Three groups of titanium abutments (pre-fabricated, height: 7.5 mm, taper: $5.7^{\circ}$; customized-long, height: 6.79 mm, taper: $4.8^{\circ}$; customized-short, height: 4.31 mm, taper: $4.8^{\circ}$) were used for luting of CAD/CAM-fabricated zirconia copings with a semi-permanent (Telio CS) and a provisional cement (TempBond NE). Retention forces were evaluated using a universal testing machine. Furthermore, the influence of cleaning methods (manually, manually in combination with ultrasonic bath or sandblasting) prior to re-cementation with a provisional cement (TempBond NE) was investigated with the pre-fabricated titanium abutments (height: 7.5 mm, taper: $5.7^{\circ}$) and SEM-analysis of inner surfaces of the copings was performed. Significant differences were determined via two-way ANOVA. RESULTS. Significant interactions between abutment geometry and luting agent were observed. TempBond NE showed the highest level of retentiveness on customized-long abutments, but was negatively affected by other abutment geometries. In contrast, luting with Telio CS demonstrated consistent results irrespective of the varying abutment geometries. Manual cleaning in combination with an ultrasonic bath was the only cleaning method tested prior to re-cementation that revealed retentiveness levels not inferior to primary cementation. CONCLUSION. No superiority for one of the two cements could be demonstrated because their influences on retentive strength are also depending on abutment geometry. Only manual cleaning in combination with an ultrasonic bath offers retentiveness levels after re-cementation comparable to those of primary luting.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.200-206
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• 2014

PURPOSE. This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane-or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS. Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate-and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (${\alpha}$=0.05). RESULTS. Mean fracture resistance for the eight groups (in Newton) were G1: $1200{\pm}169^a$, G2: $360{\pm}93^b$, G3: $632{\pm}196^c$, G4: $692{\pm}195^c$, G5: $917{\pm}159^d$, G6: $1013{\pm}125^{ad}$, G7: $959{\pm}148^d$, G8: $947{\pm}105^d$ (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION. Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.636-643
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• 1999

Ectodermal dysplasia is a genetic birth defect in which at least abnormally develop two structures derived from the ectoderm. It is usually inherited in autosomal dominant or autosomal recessive pattern. Oral manifestations are oligodontia, anodontia, dysmorphic teeth(conical shape), decreased occlusal vertical dimension and alveolar bone. Extraoral signs may include decreased or absent sweat glands, sparse and fine hair, saddle nose, hearing loss and decreased production of body fluids including saliva. Most affected children require extensive dental treatment to restore their appearance and help the development of a positive self image. The patient's overclosed profile was due to a decreased vertical dimension. The use of overdenture is to preserve erupted teeth, to accomodate the newly constructed occlusal plane, to improve retention and stability of denture and to maintain the remaining alveolar bone. The restoration of vertical dimension improved the child's speech, swallowing, and eating. Growth continue until the age of approximately 18. As child grows, replacement dentures will have to be fabricated primarily to accomodate increasing vertical dimension and changing dentition. Implants may be indicated later if the alveolar bone is adequate. Periodic recall visits are advised, to monitor the dentures during periods of growth and development, and eruption of the permanent teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.51-57
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• 2012

The anterior maxillary incisor is the most traumatized region in the mouth and trauma is frequent between the ages of 8-10. Traumatic loss of teeth, can lead to many complications in children. Thus, as possible to keep traumatic teeth, but if you need extractions There may be. Complications occur and early tooth loss is frequent. Complications of early loss of central incisors are esthetic compromise, loss of vertical and horizontal width, height, contour of alveolar bone, tilting of adjacent teeth, arch length loss. Alveolar bone loss may affect normal function and stability, and results in esthetic problem for future prosthesis restoration. The 9-year-old girl and 6-year-old boy got early loss of upper central incisor. The amount of alveolar bone resorption was measured using cone beam computed tomograph and cast analysis.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.391-398
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• 2011

The infraocclusion usually occurs in the mixed-dentition stage, and it is commonly accepted that the cause of the infraocclusion is ankylosis. The treatment options for patient with infraocclusion of primary molars are observation, restoration or surgical removal of the affected teeth. If the successors are present, most of the infraoccluded and ankylosed primary molars may occur normally. However, when the permanent successors are absent and the progression of infraocclusion is found, affected teeth may need to be extracted. In the case of infraocclusion which can cause vertical alveolar defect due to ankylosis, extraction before growth spurt should be performed for the future prosthetic treatment. A six-year-old female had the ankylosis and infraocclusion of multiple primary molars and congenital missing of premolars. The affected primary molars were extracted before growth spurt to avoid a significant vertical ridge defect and to promote the vertical development of alveolar bone, and the result was observed for many years. The purpose of this report is to report the management of multiple infraoccluded primary molars without permanent successors in a young patient.