A case of full mouth rehabilitation with orthodontic treatment in patient with extensive tooth erosion and wear using monolithic zirconia prostheses / 대한치과보철학회지

Extensive dental erosion and wear will cause serious loss of function and aesthetics in the mouth. In order to recover this condition, careful analysis of the patient's bite relationship is required. In particular, a treatment plan should be established considering the possibility of reproduction of the vertical dimension and centric relation, and appropriateness of the occlusal plane and anterior guidance. Also, the choice of prosthetic materials is an important consideration in patients with severe wear. In this case, patients with overall wear and erosion on tooth was established anterior guidance by orthodontic treatment and fully restored with monolithic zirconia, without increasing vertical dimension.

Evaluation of surface treated implant with nanotitania / Шинэ санаа Шинэ нээлт

@#Dental implants are valuable devices for restoring lost teeth. At this moment, nanotechnology has emerged with several techniques to modify implant surfaces. In addition, some evaluation techniques at the nano level are contributing important information regarding tissue and cell interactions with the implanted material. The purpose of this study was to analyze and compare the bone responses to 3 different types of 4.1-mm-diameter, 10mm-long implant surfaces on a dog femur model: 1) Sand blasted with alumina and Acid etched (SA), 2) Resorbable blast media (RBM), functioning as control groups, and 3) Anode oxidation nano-titana (Anodized TiO2) surface implants as experimental group. For this study, implants were placed in 3 beagle dogs (age, 18 months; weight, 11-14 kg). Their purchase, selection, management, and experimental procedure were carried out according to established conditions by the Department of Laboratory Animal Medicine, Medical Research Center, Medical College of Yonsei University. Nineteen turned screw-shaped implants with 3 different surfaces (4.1mm in diameter, 10mm in length) were made from commercially pure titanium (grade IV). Thirteen implants were placed in each beagle dogs no. 1 and 2 and six implants were placed in the remaining beagle dog. Implants placed in beagle dogs no. 1 and 2 underwent histology analysis, X-ray and CT taking, and analysis of relative bone mineral density with Dataviewer program. While removal torque was measured in the implants placed in beagle no. 3 after a healing period of 4 and 8 weeks. A histological evaluation of the specimens in this study showed that osseointegration was achieved for all control and experimental group after a healing period of 4 and 8 weeks. The following means were obtained for bone-implant contact (BIC) percentage for 4 and 8-week groups, respectively: SA: 85.16%, 38.88%; RBM: 41.62%, 58.87%; and Anodized TiO2: 43.85%, 61.3%. The following means were obtained for bone volume (BV) percentage for 4 and 8-week groups, respectively: SA: 34.48%, 51.55%; RBM: 58.56%, 81.56%; and Anodized TiO2: 47.22%, 63.53%. In this study, 8-week consolidated Anodized TO2 surface implants showed increased removal torque value (RTV) compared to that of the 4-week group. The obtained RTV means were 86.0 and 99.7Ncm, respectively, for 4 and 8-week Anodized TiO2 implants. The present study showed that osseointegration occurred in all investigated types of surface-treated implants. However, the control groups showed slight increase in the BIC and BIV values compared to the experimental groups. Therefore the clinical relevance of the observed results remains to be shown.

Esthetic restoration in continuous maxillary anterior area using immediate implant placement: A case report / 대한치과보철학회지

In the case of an extraction in the maxillary anterior region, immediate placement of implant-supported fixed prosthesis can be considered as a treatment option. Fewer surgical operations, reduced treatment time, and optimal availability of existing bone are obvious advantages of the method; however, when applied in the continuous maxillary anterior region, inter-implant distance must be carefully considered, as well as accurate diagnosis and treatment planning for predictable outcome. In this case report, immediate placement of two implants in the continuous maxillary anterior along with bone graft following the extraction of root rests, and the restoration of provisional and implant-supported fixed prosthesis on a 63-year-old patient had resulted in both esthetically and functionally satisfactory clinical outcomes.

Comparison of occusal aspects in monolithic zirconia crown before and after occlusal adjustment during intraoral try-in: a case report / 대한치과보철학회지

In case of prosthesis fabrication by CAD/CAM, location, area and contour of occlusal contacts can be adjusted so more functional occlusion can be acquired. Also, errors in a manufacturing process is reduced compared to cast metal prostheses and porcelain fused metal prostheses fabricated by conventional methods such as casting and porcelain build up. Therefore, prostheses by CAD/CAM show superior occlusion accuracy. Recently, virtual articulator function has been introduced to CAD/CAM system, which reproduces mandibular movement against maxilla. Thus, it is possible to consider occlusal interference in anterior/lateral movement as well as closing movement. There have been many studies on the marginal and internal fit of prostheses using zirconia but the occlusal fit of zirconia crown fabricated by CAD/CAM has not been researched as much. In this case report, 7 zirconia crowns were designed and fabricated by CAD/CAM for total 5 patients. The models of zirconia crowns before and after occlusal adjustment during intraoral try-in were scanned for occlusal contacts, which were compared to evaluate accuracy of prostheses and understand patterns of occlusal adjustment. Most of the occlusal adjustments were done on functional cusps and slopes of zirconia crown, and the magnitude of occlusal adjustment ranged from 15 microm to 60 microm. In the zirconia crown fabricated with CAD/CAM systems, the occlusal adjustment is a necessary procedure, so additional procedures will be needed for compensating reduced mechanical properties.

Retrospective study of the Implantium(R) implant with a SLA surface and internal connection with microthreads / 대한치과보철학회지

STATEMENT OF PROBLEM: Since the introduction of the concept of osseointegration in dental implants, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. PURPOSE: The aim of this retrospective study was to provide long-term data on the Implantium(R) implant, which features a sandblasted and acid-etched surface and internal connection with microthreads. MATERIAL AND METHODS: 106 Implantium(R) implants placed in 38 patients at Yonsei University Hospital were examined to determine the effect of various factors on implant success and marginal bone loss, through clinical and radiographic results during a 6 to 30 month period. RESULTS: 1. Out of a total of 106 implants placed in 38 patients, one fixture was lost, resulting in a 99.1% cumulative survival rate. 2. Among the 96 implants which were observed throughout the study period, the survival rates were 97.0% in the maxilla and 100% in the mandible. The survival rate in the posterior regions was 98.9% and 100% in the anterior regions. 3. The mean bone loss during the first year after prosthesis placement was 0.17 mm, while the mean annual bone loss after the first year was 0.04 mm, which was statistically less than during the first year (P .05), but after the first year, the mean annual bone loss in patients above 50 years was significantly greater (P < .05) compared with patients under 50 years. 5. No significant difference in marginal bone loss was found according to the following factors: gender, jaw, location in the arch, type of implant (submerged or non-submerged), presence of bone grafts, type of prostheses, and type of opposing dentition (P < .05). CONCLUSION: Based on these results, the sole factor influencing marginal bone loss was age, while factors such as gender, jaw, location in the arch, type of implant, presence of bone grafts, type of prostheses and type of opposing dentition had no significant effect on bone loss. In the present study, the success rate of the Implantium(R) implant with a SLA surface and internal connection with microthreads was satisfactory up to a maximum 30 month period, and the marginal bone loss was in accord with the success criteria of dental implants.

The comparison of microtensile bond strength with immediate and delayed dentin sealing / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the effect of various methods of dentin bonding agent application on microtensile bond strength between dentin and resin, using a 2-step etch-and-rinse dentin bonding agent. MATERIAL AND METHODS: Twenty freshly extracted human molars were obtained and divided into 4 groups of 5 teeth. 2-step etch-and-rinse dentin bonding agent was used for all groups. The control specimens were prepared using a direct immediate bonding technique. The delayed dentin sealing (A, C) specimens were prepared using an indirect approach with delayed dentin sealing. For group A, resin was built-up on uncured dentin bonding agent, and for group C, resin was built-up on pre-cured dentin bonding agent. Preparation of the immediate dentin sealing (B) specimens also used an indirect approach with immediate dentin sealing immediately following preparation. All teeth were prepared for a microtensile bond strength test. Specimens were stored in water for 24 hours. Ten beams (1.0 x 1.0 x 11 mm) from each tooth were selected for testing. Bond strength data (MPa) were analyzed with a one-way ANOVA test, and post hoc comparison was done using the Scheffe's test. RESULTS: The mean microtensile bond strengths of control group, B and C (DDS with pre-cure) were not statisticaaly different from each other at 32.7, 33.3, 34.2 MPa. the bond strength for group A (DDS without pre-cure), 19.5 MPa, was statistically different (P < .01) from the other 3 groups. CONCLUSION: When preparing teeth for indirect bonded restorations, DDS with pre-curing dentin bonding agent and IDS results in the same bond strength between dentin and resin. On the contrast, the bond strength was decreased when DDS without pre-curing dentin bonding agent was used.

Clinical and radiographic evaluation of Neoplant(R) implant with a sandblasted and acid-etched surface and external connection / 대한치과보철학회지

STATEMENT OF PROBLEM: Since the concept of osseointegration in dental implants was introduced by Branemark et al, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. PURPOSE: The aim of this retrospective study was to provide long-term data on the Neoplant(R) implant, which features a sandblasted and acid-etched surface and external connection. MATERIAL AND METHODS: 96 Neoplant(R) implants placed in 25 patients in Yonsei University Hospital were examined to determine the effect of the factors on marginal bone loss, through clinical and radiographic results during 18 to 57 month period. Results: 1. Out of a total of 96 implants placed in 25 patients, two fixtures were lost, resulting in 97.9% of cumulative survival rate. 2. Throughout the study period, the survival rates were 96.8% in the maxilla and 98.5% in the mandible. The survival rates were 97.6% in the posterior regions and 100% in the anterior regions. 3. The mean bone loss for the first year after prosthesis placement and the mean annual bone loss after the first year for men were significantly higher than that of women (P<0.05). 4. The group of partial edentulism with no posterior teeth distal to the implant prosthesis showed significantly more bone loss compared to the group of partial edentulism with presence of posterior teeth distal to the implant prosthesis in terms of mean bone loss for the first year and after the first year (P<0.05). 5. The mean annual bone loss after the first year was more pronounced in posterior regions compared to anterior regions (P<0.05). 6. No significant difference in marginal bone loss was found in the following factors: jaws, type of prostheses, type of opposing dentition, and submerged /non-submerged implants (P<0.05). CONCLUSION: On the basis of these results, the factors influencing marginal bone loss were gender, type of edentulism, and location in the arch, while the factors such as arch, type of prostheses, type of opposing dentition, submerged / non- submerged implants had no significant effect on bone loss. In the present study, the cumulative survival rate of the Neoplant(R) implant with a sandblasted and acid-etched surface was 97.9% up to a maximum 57-month period. Further long-term investigations for this type of implant system and evaluation of other various domestic implant systems are needed in future studies.

Computer-aided casting design for implant titanium superstructures / 대한치과보철학회지

STATEMENT OF PROBLEM: It is difficult to obtain a good titanium casting body using the traditional sprue design because of high melting point of Ti, and the low fluidity and high reactivity of molten Ti. PURPOSE: A new sprue design for titanium casting bodies needs more trial and error. In order to decrease the number of trial and error, computer simulation(MAGMASOFT, Magmasoft Giessereitechnologie GmbH, Achen, Germany) was used to optimize sprue design in U-shaped implant superstructures. MATERIAL AND METHOD: Five kinds of sprue were examined for the design of the sprue former for titanium casting: Sprue design A(sprue length 4 mm, rectangular shape, 4 sprues), Sprue design B(sprue length 4 mm, round shape, radius 2 mm, 7 sprues), Sprue design C (sprue length 2 mm, round shape, radius 2 mm, 7 sprues), Sprue design D (sprue length 2 mm, cone shape, large radius 3mm, small radius 2mm, 7 sprues), and Sprue design E( sprue length 2 mm, one unit channel shape). Sprue design F(sprue length 2mm, one unit channel hape) was also examined for the design of the customized sprue former in the Biotan system(Schutz Dental Gmbh, Germany). The casting bodies were taken in Sprue design A, Sprue design D, Sprue design E, and Sprue design F in the Biotan casting system. The numerically predicted defects were compared with the experimental dental castings by the radiographic and sectional view observations. RESULTS: 1. According to the result of computer simulation, turbulence during mold filling was decreased in the sequence of Sprue design F, Sprue design E, Sprue design D, Sprue design C, Sprue design B, and Sprue design A. 2. The calculated solidification time contours indicate that hot spot was moved from the casting body to the sprue button in the sequence of Sprue design A, Sprue design B, Sprue design C, Sprue design D, and Sprue design E. The filling pattern of Sprue design F was similar to that of Sprue design E. 3. The predicted filling pattern shows that less turbulence was found in the customized sprue former than in the standard sprue former. 4. According to the results of the radiographic and cross sectional observations, casting defects less than 1mm were found at the center of a casting body with Sprue design E and Sprue design F. However, larger casting defects of 4mm were found in a casting with Sprue design A. 5. The predicted casting porosity was similar to that of the real casting. CONCLUSION: One unit channel-type and customized sprue former can be recommended. Further research and development of various sprue designs using computer simulation is necessary to optimize casting design, in order to reduce the formation of casting defects in implant titanium superstructures.