• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.21-32
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• 2010

The convergence angle of a prepared tooth is a very important factor in the retention and resistance of a crown restoration. But various intraoral environments and clinician's techniques make it difficult to obtain the ideal inclination. Therefore, in this study, clinical convergence angle of a prepared tooth was investigated. The data was collected from the patient models of prosthodontic residents and the patient models of general practitioners. The images of mesiodistal and buccolingual surfaces were taken with a digital camera to evaluate the convergence angle on 'ImageJ' program. The images were classified according to the criteria (1. Clinician group, 2. Position in the dental arch, 3. The purpose of abutment preparation)and then analyzed. The mean convergence angle of a prepared tooth for Korean clinicians was $15.02^{\circ}$ (${\pm}10.13^{\circ}$). 1. It was significant in the convergence angle between the general practitioner group and the prosthodontic resident group(p<0.05). 2. It was significant between the mesiodistal and buccolingual surface in the the prosthodontic resident group(p<0.05). 3. For the general practitioner group, it was significant when anteriors and premolars were compared with molars(p<0.05). For the prosthodontic resident group, it was significant when anteriors and premolars were compared with molars (p<0.05). 4. When divided into upper and lower arches, for the general practitioner group, it showed significant difference in the buccolingual aspect(p<0.05). Also in the prosthodontic resident group, it showed significant difference in the buccolingual aspect(p<0.05). 5. Dividing left and right sides of the arches, there was no significant difference in the general practitioner group and the prosthodontic resident group(p>0.05). 6. In the general practitioner group, it was significant in the mesiodistal axial convergence angle of single crown abutment and 3 unit bridge abutment(p<0.05). In the prosthodontic resident group, it was significant in the mesiodistal and overall axial convergence angle of single crown abutment and 3 unit bridge abutment(p<0.05). Clinical convergence angle of prepared tooth in Korea was included in agreement with other studies investigating convergence angle that ranged from 10 to 22 degrees, achieved in clinical practice.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.207-214
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• 2008

Purpose: The aim of augmentation of the alveolar ridge is to restore absorbed alveolar ridges for future implant site or esthetic prosthodontic restoration. The present clinical report describes the anterior maxillary augmentation cases using a soft tissue rotated palatal flap, and considers various problems of before and after surgery. Method: First & second patients were treated by vascularized interpositional periosteal-connective tissue(VIP-CT) flap for horizontal soft tissue augmentation. Especially second patient was progressed with bone grafting at the same time. Third patient was treated by the same flap with bone graft and implant placement in single tooth missing premaxillary area. Result: The obtained horizontal augmentation width measured $0.5{\sim}2.7\;mm$. Conclusion: This technique constitutes a viable approach for augmentation the anterior sector of alveolar ridge with the placement of dental implants. But it needs correct diagnosis preparation and careful surgery skill.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.185-193
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• 2014

PURPOSE. The purpose of this study was to evaluate the intra-rater reliability and inter-rater reliability of three different methods using a drawing protractor, a digital protractor after tracing, and a CAD system. MATERIALS AND METHODS. Twenty-four artificial abutments that had been prepared by dental students were used in this study. Three dental students measured the convergence angles by each method three times. Bland-Altman plots were applied to examine the overall reliability by comparing the traditional tracing method with a new method using the CAD system. Intraclass Correlation Coefficients (ICC) evaluated intra-rater reliability and inter-rater reliability. RESULTS. All three methods exhibited high intra-rater and inter-rater reliability (ICC>0.80, P<.05). Measurements with the CAD system showed the highest intra-rater reliability. In addition, it showed improved inter-rater reliability compared with the traditional tracing methods. CONCLUSION. Based on the results of this study, the CAD system may be an easy and reliable tool for measuring the abutment convergence angle.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.26 no.1
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• pp.24-38
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• 2017

Prosthetics procedures in dental clinics 1) Tooth preparation 2) Temporary restoration 3) Post and core 4) Impression 5) Cementation of final prosthesis The final step in the prosthodontic procedure is the fitting of the final prosthesis to the patient's abutment with an exact fit and occlusal relationship. By the way, this final prosthesis is not made in the clinic but is made in the dental lab and comes to the clinic with some time difference. In the clinic, the only medium to deliver the patient's oral information to the dental laboratory is the impression. However, many errors occur in this process. Dentists and dental technicians should try to identify the cause and make an accurate prosthesis to reduce this error.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.477-482
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• 2010

In a case of multiple posterior teeth loss, antagonistic teeth extrude to the edentulous space and compensatory occlusion on the remained anterior teeth leads to occlusal trauma. Extrusion of antagonistic teeth breaks down occlusion plane and loss of posterior support bring about severe wear of remained teeth. In this situation, it is needed to restore remained teeth and edentulous space by increasing vertical dimension to obtain prosthodontic rehabilitation space and to correct occlusion plane. In this case report, the patient had a masticatory problem with loss of posterior teeth support and an esthetic problem of shortened anterior teeth. Before the tooth preparation for the prosthodontic restoration, the patient used removable device for 2 months to increase vertical dimension reversibly. After that, he got provisional fixed restoration with irreversible tooth reduction and used it for 3 months. It had spent 5 month to evaluate the adaptation state on final restoration with incresed vertical dimension. The increasing amount was 3 mm, which was relatively in less degree and masticatory system adapted to the increased vertical dimension without any pathologic changes. Final restoration was made to have equal-intensity contacts on all teeth in a verifiable centric relations and immediate disclusion of all posterior contacts the moment the mandible moves in any direction from centric relation. In addition, metal occlusion surface on posterior teeth was applied to prevent excessive muscle activation, occlusal trauma and the porcelain fracture.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.3
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• pp.231-242
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• 2006

Statement of problem: The sealing of the opened dentinal tubules that follows the tooth preparation for the prosthodontic restoration is considered as clinical process to reduce postoperative sensitivity. Purpose: This study investigated the effect of desensitization treatment on shear bond strength of luting cements. Materials and Method: Total 80 dentin specimens were divided into two groups according to the kinds of luting cements. Each groups was further divided into 4 subgroups with AQ $bond^{(R)}$, $Saforide^{(R)}$, Diode laser $MDL-10^{(R)}$ application and without desensitization treatment. After desensitization treatment application, Ni-Cr specimens were luted to dentin surface with Fuji $CEM^{(R)}$ and $Panavia-F^{(R)}$. Specimens were placed in distilled water at $37^{\circ}C$ for 24 hours and shear bond strength between metal and dentin was measured by a universal testing machine. Results: 1. In Fuji $CEM^{(R)}$ cemented groups, the combination of AQ $bond^{(R)}$ showed the greatest strength, followed by diode laser, no desensitizer treatment, and $Saforide^{(R)}$. Both AQ $bond^{(R)}$ and Diode laser groups had a significant difference than no desensitization treatment group and $Saforide^{(R)}$ group(p<0.05). 2. In $Panavia-F^{(R)}$ cemented groups, the combination of Diode laser showed the greatest strength, followed by AQ $bond^{(R)}$, $Saforide^{(R)}$, and No desensitization treatment. All desensitization treatment groups had a significant difference than no desensitization treatment group(p<0.05). 3. All $Panavia-F^{(R)}$ groups showed a significant higher shear bond strength than all Fuji $CEM^{(R)}$ groups(p<0.05). Conclusion: The results of this study showed possibility of bond strength increase after desensitization treatment. The application of desensitization treatments like AQ $bond^{(R)}$, $Saforide^{(R)}$, and Diode laser $MDL-10^{(R)}$ have advantages in exposed dentin surface after tooth prep.

• 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.