• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.128-134
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• 2012

Purpose: The purpose of this study was to compare the screw joint stability between the CADCAM custom-made implant abutment and the prefabricated implant abutment by measuring the reverse torque value after cyclic loading. Materials and methods: Twelve screw type implants (Implantium, Dentium Co., Seoul, Korea) were embedded in aluminum cylinder with acrylic resin. The implant specimens were equally divided into 3 groups, and connected to the prefabricated titanium abutments (Implantium, Dentium Co., Seoul, Korea), CADCAM custom-made titanium abutments (Myplant, Raphabio Co., Seoul, Korea) and CADCAM custom-made zirconia abutments (Zirconia Myplant, Raphabio Co., Seoul, Korea). The CAD-CAM milled titanium crown (Raphabio Co., Seoul, Korea) was cemented on each implant abutment by resin cement. Before cyclic loading, each abutment screw was tightened to 30 Ncm and the reverse torque value was measured about 30 minutes later. After the crown specimen was subjected to the sinusoidal cyclic loading (30 to 120 N, 500,000 cycles, 2 Hz), postloading reverse torque value was measured and the reverse torque loss ratio was calculated. Kruskal-Wallis test was used for statistical analysis of the reverse torque loss ratio. Results: The CADCAM custom-made titanium abutments presented higher values in reverse torque loss ratio without statistically significant differences than the prefabricated titanium abutments ($P$>.05). Reverse torque loss ratio of the custom-made zirconia abutments was significantly higher compared to that of the prefabricated titanium abutments ($P$=.014). Conclusion: Within the limitation of the present $in-vitro$ study, it was concluded that there was no significant difference in screw joint stability between the CADCAM custom-made titanium abutments and the prefabricated titanium abutments. On the other hand, the CADCAM custom-made zirconia abutments showed lower screw joint stability than prefabricated titanium abutments.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.198-203
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• 2013

PURPOSE. The purpose of this study was to investigate the effect of resin cements and primer on the retentive force of zirconia copings bonded to zirconia abutments with insufficient retention. MATERIALS AND METHODS. Zirconia blocks (Lava, 3M ESPE, St. Paul, MN, USA) were obtained and forty sets of zirconia abutments and copings were fabricated using CAD/CAM technology. They were grouped into 4 categories as follows, depending on the types of resin cements used, and whether the primer is applied or not:Panavia F2.0 (P), Panavia F2.0 using Primer (PRIME Plus, Bisco Inc, Schaumburg, IL, USA) (PZ), Superbond C&B (S), and Superbond C&B using Primer (SZ). For each of the groups, the cementation was conducted. The specimens were kept in sterilized water ($37^{\circ}C$) for 24 hours. Retentive forces were tested and measured, and a statistical analysis was carried out. The nature of failure was recorded. RESULTS. The means and standard deviations of retentive force in Newton for each group were $265.15{\pm}35.04$ N (P), $318.21{\pm}22.24$ N (PZ), $445.13{\pm}78.54$ N (S) and $508.21{\pm}79.48$ N (SZ). Superbond C&B groups (S & SZ) showed significantly higher retentive force than Panavia F2.0 groups (P & PZ). In Panavia F2.0 groups, the use of primer was found to contribute to the increase of retentive force. On the other hand, in Superbond C&B groups, the use of primer did not influence the retention forces. Adhesive failure was observed in all groups. CONCLUSION. This study suggests that cementation of the zirconia abutments and zirconia copings with Superbond C&B have a higher retentive force than Panavia F2.0. When using Panavia F2.0, the use of primer increases the retentive force.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.20 no.1
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• pp.78-83
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• 2011

• 대한치과보철학회:학술대회논문집
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• 1999.04a
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• pp.76.1-76.1
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• 1999

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.329-332
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• 2016

Fabricating a surveyed prosthesis beneath an existing partial removable dental prosthesis (PRDP) is a challenging and time-consuming procedure. The computer-aided design/computer-assisted manufacturing (CAD/CAM) technology was applied to fabricate a retrofitted, surveyed zirconia prosthesis to an existing PRDP. CAD/CAM technology enabled precise and easy replication of the contour of the planned surveyed crown on the existing abutment tooth. This technology ensured excellent adaptation and fit of newly fabricated crown to the existing PRDP with minimal adjustments. In this case report, a seventy-year-old male patient presented with fractured existing surveyed crown. Because the existing PRDP was serviceable, new crown was fabricated to the existing PRDP.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.201-212
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• 2012

There are some similar aspects at histological and morphological characteristics between the peri-implant tissue and periodontal tissue and the direct attachment between the titanium and soft tissue around the implant called as "Functional ankylosis" can prevent the apical infiltration of inflammatory and bone resorption around implant. But, the repeated connection and disconnection of the abutment can destroy the mucosal barrier of soft tissue around the implant and can cause the marginal bone resorption. The amount of marginal bone resorption may reduced if the prosthetic abutment is placed at that time of surgery. Connection of the prosthetic abutment at surgery was limited because the low accuracy of conventional method, but by using of Cone Beam Computed Tomography(CBCT) and guide surgery, the 3-dimensional accuracy of implant placement became much higher than before and it became possible. This is a clinical case of immediate connection of prosthetic abutment and provisional restoration by using of precise CBCT diagnosis and pre-fabricated zirconia customized abutment at surgery and the alternative method is described in this article because of the clinically contentable results.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.352-358
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• 2014

They have been recently introduced many aesthetic implant prosthesis using with zirconia and CAD/CAM. However, there are many limitations in their gingival and occlusal region. In this case, submucosal zirconia implant prosthesis were fabricated with CAD/CAM system. The connection of these screw cement retained prosthesis and titanium abutment was designed to 1mm above the fixture. The clinical results were satisfactory on the aesthetics and function.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.218-224
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• 2017

The implant-supported fixed dental prosthesis in irradiated maxilla needs meticulous treatment planning due to low bone healing capacity. All-on-4 concept implantation can reduce the number of implants to be placed avoiding bone grafting procedure. Conventionally, prefabricated angled abutments for tilted implants have been used. However, in this case, it was replaced with computer-aided design and computer-aided manufacturing (CAD/CAM) abutment. This case report described all-on-4 concept implantation and fabrication of CAD/CAM zirconia fixed dental prostheses using CAD/CAM titanium abutments.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.381-387
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• 2018

PURPOSE. Cement-retained implant prostheses can lack proper retrievability during repair, and residual cement can cause peri-implantitis. The purpose of this in vitro study was to evaluate the influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with lingual slots, known as retrievable cement-type slots (RCS). MATERIALS AND METHODS. We fabricated six types of titanium abutments (10 of each type) with two different heights (4 mm and 6 mm), three different convergence angles ($8^{\circ}$, $10^{\circ}$, and $12^{\circ}$), a sloped shoulder margin (0.6 mm depth), a rectangular shape ($6mm{\times}6.5mm$) with rounded edges, and a rectangular ledge ($2mm{\times}1mm$) for the RCS. One monolithic zirconia crown was fabricated for each abutment using a dental computer-aided design/computer-aided manufacturing system. The abutments and crowns were permanently cemented together with dual-curing resin cement, followed by 24 hours in demineralized water at room temperature. Using a custom-made device with a slot driver and torque gauge, we recorded the torque ($N{\cdot}cm$) required to remove the crowns. Statistical analysis was conducted using multiple regression analysis and Mann-Whitney U tests (${\alpha}=.05$). RESULTS. Removal torques significantly decreased as convergence angles increased. Multiple regression analysis showed no significant interaction between the abutment height and the convergence angle (Durbin-Watson ratio: 2.186). CONCLUSION. Within the limitations of this in vitro study, we suggest that the retrievability of cement-retained implant prostheses with RCS can be maintained by adjusting the abutment height and convergence angle, even when they are permanently cemented together.

• The Journal of Advanced Prosthodontics
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• v.12 no.4
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• pp.233-238
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• 2020

PURPOSE. This study aims to compare the marginal fitness of two types of implant-supported fixed dental prosthesis, i.e., cementless fixation (CL.F) system and cement-retained type. MATERIALS AND METHODS. In each group, ten specimens were assessed. Each specimen comprised implant lab analog, titanium abutment fabricated with a 2-degree tapered axial wall, and zirconia crown. The crown of the CL.F system was retained by frictional force between abutment and relined composite resin. In the cement-retained type, zinc oxide eugenol cement was used to set crown and abutment. All specimens were sterilized with ethylene oxide, immersed in Prevotella intermedia culture in a 50 mL tube, and incubated with rotation. After 48 h, the specimens were washed thoroughly before separating the crown and abutment. The bacteria that penetrated into the crown-abutment interface were collected by washing with 500 µL of sterile saline. The bacterial cell number was quantified using the agar plate count technique. The BacTiter-Glo Microbial Cell Viability Assay Kit was used to measure bacterial adenosine triphosphate (ATP)-bioluminescence, which reflects the bacterial viability. The t-test was performed, and the significance level was set at 5%. RESULTS. The number of penetrating bacterial cells assessed by colony-forming units was approximately 33% lower in the CL.F system than in the cement-retained type (P<.05). ATP-bioluminescence was approximately 41% lower in the CL.F system than in the cement-retained type (P<.05). CONCLUSION. The CL.F system is more resistant to bacterial penetration into the abutment-crown interface than the cement-retained type, thereby indicating a precise marginal fit.