• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.376-384
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• 2009

Purpose: The purpose of this study was to evaluate the response of osteoblast-like cells to Ca-P coated surface obtained via Ion beam-assisted deposition (IBAD) method and Sol-Gel process on anodized surface by cellular proliferation and differentiation. Material and methods: The surface of a commercially pure titanium (Grade IV) discs with dimension of 10mm diameter and 2 mm thickness was modified by anodic oxidation under a constant voltage of 300 V. The experimental groups were coated with Ca-P by the IBAD method and Sol-Gel process on anodized surface. The surface roughness (Ra) of specimens was measured by optical interferometer and each surface was examined by SEM. To evaluate cell response, MG63 cells were cultured and cell proliferation, ALP activity and the ability of cell differentiation were examined. Also, cell morphology was examined by SEM. The significant of each group was verified by Kruskal-Wallis Test ($\alpha$=.05). Results: The Ra value of Ca-P coated surface by IBAD method was significantly higher than Ca-P coated surface by Sol-gel process (P < .05). The level of cell proliferation and ALP activity was higher in Ca-P coated surface by IBAD method (P<.05). The expression of ALP showed higher level expression in Ca-P coated surface by IBAD method. Cells grown on Ca-P coated surface by IBAD method were uniformly distributed and developed a very close layer. Conclusion: These experiments showed better performances of Ca-P coated surface by IBAD method with respect to Ca-P coated surface by Sol-gel process. Ca-P coated surface by IBAD method appear to give rise more mature osteoblast characteristics and might result in increased bone growth and bone-implant contact.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.3
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• pp.189-198
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• 2017

Purpose: This study aims to analyze the stress distribution of mandibular molar restoration supported by the implants with external hex and internal taper abutment connection design. Materials and Methods: Models of external connection (EXHEX) and internal connection (INCON) implants, corresponding abutment/crowns, and screws were developed. Supporting edentulous mandibular bony structures were designed. All the components were assembled and a finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. A total of 120 N static force was applied both by axial (L1) and oblique (L2) direction. Results: Peak von Mises stresses produced in the implants by L2 load produced 6 - 15 times greater than those by L1 load. The INCON model showed 2.2 times greater total amount of crown cusp deflection than the EXHEX model. Fastening screw in EXHEX model and upside margin of implant fixture in INCON model generated the peak von Mises stresses by oblique occlusal force. EXHEX model and INCON model showed the similar opening gap between abutment and fixture, but intimate sealing inside the contact interface was maintained in INCON model. Conclusion: Oblique force produced grater magnitudes of deflection and stress than those by axial force. The maximum stress area at the implant was different between the INCON and EXHEX models.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.3
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• pp.557-565
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• 1997

Screw-shaped implants of commercially pure (c.p.) titanium, c.p. niobium, c.p. zirconium, and stainless steel(Sus 304) were inserted in the rabbit tibial bone over 12 weeks of follow-up. New developed torque gauge instrument was used to evaluate the implant holding power and a image analysis program coupled to a microscope was used for histomorphometry. The three best consecutive threads of each implant were measured. Quantitative analyses at 12 weeks revealed a partial bone contact to the four kinds investigated metals. There were no obvious adverse tissue reactions to any of the biomaterials. At 12 weeks the average removal torques for titanium, niobium and zirconium were better than that needed for Sus 304 screws, on the other hand high score of bony contact ratio of titanium and niobium were showed in comparison to those of zirconium and Sus 304. There was no significant differences in the amount of interfacial bone of zirconium and Sus 304 whereas there was significant difference in the torque forces of niobium and Sus 304. Three months after implant insertion, the average removal torque was 6.64 Ncm for the titanium, 6.57 Ncm for the niobium, 6.38 Ncm for the zirconium, and 4.25 Ncm for the Sus 304. On average bone contacts there were 51.24% in the titanium, 48.19% in the niobium, 31.79% in the zirconium, 23.54% in the Sus 304. Biocompatibility of the titanium, niobium and zirconium was acceptable level in comparison to the Sus 304.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.35-40
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• 2005

This paper reports the morphological nature of the remodelled interface process between implants and surrounding bone after 1, 4, 6, 8 and 12 weeks of implantation of smooth machined implants into rat tibias. After 4 weeks of implantation, histochemical analysis showed that the new bone was growing in direct contact with the implant. In the forming process, the activatived osteoblast cells migrated toward the interface and colonized the surface at the contact areas. This immature woven bone, rich in osteocyte lacunae, was deposited directly onto the implant surface. Osteoblast activity was found to continue ill 12 weeks of implantation The osteoblasts in lacunar areas developed numerous processes and synthesized bone matrix, after all, surrounded by secreting matrix. At the 12th week, the amount of newly formed bone matrix between bone and implant increased in mineralization. The mineralized mature bone contained well organized collagen fibers with characteristic banding pattern bone tissue formation around the implant.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.603-610
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• 2008

Purpose: The guided bone regeneration (GBR) technique is widely used in periradicular surgery. However, there is still some controversy regarding the effectiveness of GBR in promoting bone healing after periradicular surgery. The purpose of this study was to evaluate the resorbable membrane on the osteointegration of immediate implants in sites with periradicular lesion that had been removed by periradicular surgery. Materials and methods: Six roots of lower second premolars and 15 roots of lower third and fourth premolars of dogs were used as control and experimental teeth, respectively. Periradicular lesions were induced only in the experimental teeth. Twelve weeks later, the control and experimental teeth were extracted and implants were placed immediately. Periradicular lesions were removed with osteotomy, curettage and saline irrigation. Resorbable membranes were used in experimental group 1 but not in experimental group 2. After 12 week of healing period, the implants were clinically not mobile and showed no signs of infection. Data obtained by histomorphometric analysis were analyzed by Kruskal-Wallis test. Results: The control group showed a significantly higher bone to implant contact (BIC) ($74.14{\pm}16.18$) than experimental group 1 ($40.28{\pm}15.96$) and 2 ($48.70{\pm}17.75$)(p<0.05). However, there was no significant difference between experimental group 1 and 2. Conclusion: Although BIC in experimental groups were lower than in control group, immediate implant can be successfully placed at extraction socket with periradicular lesion and osseous defect. However, the use of resorbable membrane in bony defect created during periradicular surgery was questioned.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.308-315
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• 2023

In the case of a patients who have lost the centric stop and have a staggered occlusion of the residual teeth, various movements occur when the denture is loaded. Implant placement is necessary to reinforce the retention, support, and stabilization elements to reduce denture movement. However, in this case, considering the patient's age, aversion to surgery, and bone loss, implants were not placed and restoration was performed with a removable partial denture. In this case, it is important to set the correct mandibular position for restoration because the patient has a habit of chewing with the remaining teeth. In this case, a stable mandibular position was established using a gothic arch tracing, and good results were obtained by restoring with partial dentures, so this is reported.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.60-68
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• 2022

A patient with severe periodontitis has causative factors that cause pathological tooth movement, the occlusion is disintegrated, and the vicious cycle of worsening periodontitis is repeated. In particular, when pathological tooth movement occurs in the maxillary anterior region, the patient has an aesthetic sense of atrophy, and the quality of life was reduced. Therefore, when orthodontic treatment was added to patients with severe periodontitis, it promotes the formation of new bone, reduces periodontal cysts, and obtains clinical attachment, which leads to favorable results in prosthetic restoration, thereby enabling ideal occlusion, function and aesthetics. Periodontal treatment, orthodontic treatment, natural tooth restoration, and implant prosthesis were planned for patients with pathological tooth movement in the anterior region due to loss of occlusal support in the posterior region. As a result, an ideal restoration space was secured, a stable restoration of occlusal contact was formed, and the maxillary anterior teeth were aesthetically improved.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.211-221
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• 2014

Purpose: The purpose of this study was to evaluate the surface characteristics and response of osteoblast-like cell at SLA surface treated with NaOH. Materials and methods: Three kinds of specimens were fabricated for the experiment groups. Control group was a machined surface, SLA group was a conventionally SLA treated surface, and SLA/NaOH gorup was SLA surface treated with NaOH. To evaluate the surface characteristics, the surface elemental composition (XPS), surface roughness and surface contact angle were evaluated in each group. And the cytotoxicity, cell adhesion, cell proliferation and ATP activity of osteoblast-like cells (MG-63 cells) were compared in each group for evaluatation of the cell responses. Statistical comparisons between groups were carried out via one-way ANOVA using the SPSS software (SPSS Inc., Chicago, USA), and then performed multiple comparisons. The differences were considered statistically significant at P<.05. Results: SLA surface treated with NaOH (SLA / NaOH group) was changed to hydrophilic surface. All groups did not show the cytotoxicity to the MG-63. In cell adhesion studies, SLA / NaOH group showed the higher degree of adhesion than anothers (P<.05), Up to 7 days of incubation, the proliferation was showed the increasing tendency in all groups but SLA / NaOH group showed the highest cell proliferation between the three groups (P<.05). At 7 days of incubation, there was no difference in ALP activities between the three groups, but at 14 days, SLA / NaOH group showed significant increase in ALP activities (P<.05). Conclusion: In this study, SLA surface treated with NaOH promoted cell adhesion, proliferation and differentiation. It means that SLA/NaOH group is possible to promote osseointegration of implants.