• 대한치과보철학회지
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• 제55권2호
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• pp.151-155
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• 2017

목적: 이 연구의 목적은 새로운 타이타늄 구성요소를 가진 지르코니아 지대주의 나사 제거력의 변화에 대해 알아보는 것이다. 내부연결 임플란트를 위한 새로운 지르코니아 지대주의 동적하중 후 지대주 나사의 제거력을 기존의 타이타늄 지대주와 비교하여 분석하였다. 재료 및 방법: 내측연결 임플란트와 타이타늄 지대주, 타이타늄 구성요소를 가진 지르코니아 지대주를 준비하였다. 12개의 내부연결형 임플란트에 6개의 타이타늄 지대주를 연결하고(대조군), 6개의 타이타늄 구성요소를 가진 지르코니아 지대주(실험군)를 30 Ncm의 토크로 연결한 후 동적하중 전후의 나사 제거력을 측정하였다. 동적 만능재료시험기를 사용하여 연결체의 장축과 30도 각도를 이루도록 하고 300 N 하중크기로 100만번의 하중이 가해졌다. 동적하중 전후의 지대주 나사 제거력을 t검정을 통해 신뢰구간 95%로 통계적 유의성을 검증하였다. 결과: 두 그룹 모두에서 동적하중 후 나사 풀림을 보이지 않았다. 동적 하중 전후의 나사 제거력은 두 그룹 모두에서 통계적으로 유의한 차이가 있게 나타났다(P < .05). 동적 하중 전후의 나사 제거력 차이는 대조군에서 $-7.25{\pm}1.50Ncm$, 실험군에서 $-7.33{\pm}0.93Ncm$ 로 나타났다. 통계분석 결과 두 군간에 나사 제거력 차이에서는 유의한 차이를 보이지 않았다(P > .05). 결론: 이 실험의 결과에 한하여 타이타늄 구성요소를 사용한 지르코니아 지대주의 동적하중 후 지대주 나사 제거력의 변화는 타이타늄 지대주와 통계학적으로 유의한 차이를 보이지 않았다.

• The Journal of Advanced Prosthodontics
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• 제15권3호
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• pp.114-125
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• 2023

PURPOSE. The aim of the study was to evaluate the optical properties of new generation (3Y-TZP) monolithic zirconia (MZ) with different abutment types and resin cement shades. MATERIALS AND METHODS. A1/LT MZ specimens were prepared (10 × 12 × 1 mm, N = 30) and divided into 3 groups according to cement shades as transparent (Tr), yellow (Y) and opaque (O). Abutment specimens were obtained from 4 different materials including zirconia (Group Z), hybrid (Group H), titanium (Group T) and anodized yellow titanium (Group AT). MZ and abutment specimens were then cemented. L^*, a^*, and b^* parameters were obtained from MZ, MZ + abutment, and MZ + abutment + cement. ∆E₀₀₁^* (between MZ and MZ + abutment), ∆E₀₀₂^* (between MZ and MZ + abutment + cement) and ∆E₀₀₃^* (between MZ + abutment and MZ + abutment + cement) values were calculated. Statistical analyses included 2-way ANOVA, Bonferroni, and Paired Sample t-Tests (P < .05). RESULTS. Abutment types and resin cements had significant effect on L^*, a^*, b^*, ∆E₀₀₁^*, ∆E₀₀₂^*, and ∆E₀₀₃^* values (P < .001). Without cementation, whereas zirconia abutment resulted in the least discoloration (∆E₀₀₁^* = 0.68), titanium abutment caused the most discoloration (∆E₀₀₁^* = 4.99). The least ∆E₀₀₂^* = 0.68 value was seen using zirconia abutment after cementation with yellow shaded cement. Opaque shaded cement caused the most color change (∆E₀₀₃^* = 5.24). Cement application increased the L^* values in all groups. CONCLUSION. The least color change with/without cement was observed in crown configurations created with zirconia abutments. Zirconia and hybrid abutments produced significantly lower ∆E₀₀₂^* and ∆E₀₀₃^* values in combination with yellow shaded cement. The usage of opaque shaded cement in titanium/anodized titanium groups may enable the clinically unacceptable ∆E₀₀^* value to reach the acceptable level.

• 구강회복응용과학지
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• 제27권2호
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• pp.185-195
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• 2011

본 연구는 외부연결방식(external type)의 임프란트에서 기존의 타이타늄 지대주와 지르코니아 지대주를 각각의 임플란트와 연결하여 하중을 가한 후 임플란트 외부육각기둥(external hexgon)부분 및 platform 표면변화를 FESEM 상으로 관찰하고, 임프란트와 타이타늄 지대주 및 지르코니아 지대주의 Viker's 경도를 측정하였다. 1. 임프란트, 타이타늄 지대주 및 지르코니아 지대주의 Viker's 경도는 각각 평균 $309.80{\pm}11.78$ HV, $318.40{\pm}11.82$ HV, $1495.30{\pm}16.21$ HV였다. 임프란트와 타이타늄 지대주 사이에는 통계학적으로 유의성이 존재하지 않았지만(P>0.05, Anova), 임프란트와 지르코니아 사이에는 통계학적으로 유의성이 관찰되었다(P<0.05, Anova). 2. 10,000번 하중을 가한 후 임플란트 표면변화 관찰에서 타이타늄 지대주 그룹과 지르코니아 지대주 그룹 모두에서 마모가 관찰 되었으며, 지르코니아 지대주에서 보다 현저한 마모양상을 나타내었다. 본 연구에서 표면경도의 차이로 인하여 타이타늄 지대주를 사용할 때보다 지르코니아 지대주를 사용한 경우 임플란트의 external hexagon부분 및 플랫폼의 마모도가 현저하였다.

• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.46-52
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• 2014

PURPOSE. The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments. MATERIALS AND METHODS. An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of ${\pm}0.1{\mu}m$ at 50 points. RESULTS. Initial detorque values of milled abutment were significantly higher than those of cast abutment (P<.05). Detorque values after one million dynamic cyclic loadings were not significantly different (P>.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (P<.05). There was no significant difference of gap dimension between the milled abutment group and the cast abutment group after cyclic loading. CONCLUSION. In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment.

• 대한치과의사협회지
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• 제54권2호
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• pp.123-133
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• 2016

Currently increasing use of implants, especially in anterior implant esthetics has become a major concern for both the patient and dentist. In the case of thin biotype if the thickness of the gingival soft tissue is less than 2mm, human eye can detect differences of colors depends on underlying materials. The zirconia abutment can be use not only for better esthetics but also for the hygienic because it is less attractive for the plaque deposition when it compare to the metals. Zirconia itself has many advantages as a biomaterial but also has frequent mechanical problems when it use for abutment of internal connection implant. For prevention or reduction of mechanical failures, use of titanium-link with zirconia super-structure which part that connects directly into the implant can be a good alternative. In this literature, I would like to review the clinical considerations of use of titanium link - CAD/CAM zirconia abutment for dental implant in esthetically important areas.

• 대한치과보철학회지
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• 제41권4호
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• pp.503-518
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• 2003

Statement of problem : There have been previous studies about considerable variations in machining accuracy and consistency in the implant-abutment-screw interfaces. Purpose : The purpose of this study was to evaluate the machining accuracy and consistency of implant/abutment/screw combinations on two randomly selected implants from each of four manufactures. Material and methods : In this study, screws were respectively used to secure a cemented abutment, to a hexlock implant fixture ; teflon coated titanium alloy screw(Torq-Tite) and titanium alloy screw in Steri--Oss system, gold-plated gold-palladium alloy screw(Gold-Tite) and titanium alloy screw in 3i system gild screw ana titanium screw in AVANA Dental Implant system, and titanium screws in Paragon System. The implants were perpendicularly mounted in polymethyl methacrylate autopolymerizing acrylic resin block(Orthodontic resin, Densply International Inc. USA) by use of dental surveyer. Each abutment screw was secured to the implant with recommended torque value using a digital torque controller. Each screw was again tightened after 10 minutes. All samples were cross sectioned with grinder-polisher unit(Omnilap 2000 SBT Inc) after embeded in liquid unsaturated polyester (Epovia, Cray Valley Inc) Results : There were the largest gaps in the neck areas of screws in hexagonal extension implants which were examined in this study. The leading edge of the abutment screw thread (superior surface) was in contact with the implant body thread, and the majority of the contacting surfaces were localized to the middle portion of the mating threads. Considerable variation in the contacting surfaces was noted in the samples evaluated. Amounts of contact in the abutment screw thread were larger for assemblies with Gold-Tite screw, gold alloy screw. Torq-Tite screw than those with titanium screws. The findings of intimate contact between the screw and screw seat were seen in all samples, regardless of manufacturers. However, microgap between the head and lateral neck surface of the screw and the abutment could be dectected in all samples. The findings of intimate contact between the platform of the implant and the bottom of the abutment were consistent in all samples, regardless of manufacturers. However, microgaps between the lateral surface of external hex of the fixture and the abutment could be dectected in all samples. Conclusion : Considerable variations in machining accuracy and consistency were noted in the samples and the implant-abutment-screw interfaces were incomplete. From the results of this study, further development of the system will be required, including improvements in pattern design.

• 대한치과보철학회지
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• 제43권6호
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• pp.727-735
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• 2005

Statement of problem. Platform switching in implant prosthesis has been used for esthetic and biological purpose. But there are few reports for this concept. Purpose. The purpose of this study is evaluation of platform switching in wide implant by three dimensional finite element analysis. Materials and Methods. The single implant and prosthesis was modeled in accordance with the geometric designs for Osstem implant system. Three-dimensional finite element models were developed for (1) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with wide cemented abutment, titanium alloy abutment screw, and prosthesis (2) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with regular cemented abutment, titanium alloy abutment screw and prosthesis(platform switching) was made for finite element analysis. The abutment screws were subjected to a tightening torque of 30 Ncm. The amount of preload was hypothesized to 650N, and round and flat type prostheses were loaded to 200 N. Four loading offset point (0, 2, 4, 6 mm from the center of the implants) were evaluated. Models were processed by the software programs HyperMesh and ANSA. The PAM-CRASH 2G simulation software was used for analysis of stress. The PAM-VIEW and HyperView were used for post processing. Results. The results from experiment were as follows; 1. von Mises stress value is increased in order of bone, abutment, implant and abutment screw. 2. von Mises stress of abutment screw is lower when platform switching. 3. von Mises stress of implant is lower when platform switching until loading offset 4 mm. 4. von Mises stress of abutment is similar between each other. 5. von Mises stress of bone is slightly higher when platform switching. Conclusion. The von Mises stress pattern of implant components is favor when platform switch ing but slightly higher in bone stress distribution than use of wide abutment. The research about stress distribution is essential for investigation of the cortical bone loss.

• 대한치과의사협회지
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• 제54권3호
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• pp.191-197
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• 2016

In the past, restoration of implant crown, ready-made abutment produced by implant manufacturer could only be used. Using straight, angled abutment, there was a limit in adaptation multiple implants. Recently, with the development of implant and CAD/CAM technology, CAD/CAM customized abutment use has become possible which is different from the past when restoration was possible with only prefabricated abutment. Not only it makes emergence profile possible which is similar to natural teeth, but also it makes insertion path possible on CAD in multiple implant restorations. However, on anterior teeth which dental esthetics is very important, another restorations which are formed with natural colored gingiva area could be required. Titanium-based zirconia prostheses which have titanium connection and zirconia structure from 1mm above fixture platform are alternative. Therefore, the purpose of this review is to analyze the characteristics, advantages and disadvantages of the abutment which is used in multiple implant restorations, and to choose right abutment when clinical trials.

• The Journal of Advanced Prosthodontics
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• 제15권1호
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• pp.33-43
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• 2023

PURPOSE. This study investigated the physical and mechanical changes in the titanium base of three different hybrid abutment materials after cyclic loading by estimating the post-load reverse torque value (RTV), compressive side fulcrum wear pattern of titanium base, and surface roughness. MATERIALS AND METHODS. A total of 24 dental implants were divided into three groups (n = 8 each): Group Z, LD, and P used zirconia, lithium disilicate, and polyetheretherketone, respectively, for hybrid abutment fabrication. RTV was evaluated after cyclic loading with 50 N for 1.2 × 10⁶ chewing cycles. The compressive sides of the titanium bases were analyzed using a scanning electron microscope, and the roughness of the affected areas was measured using an optical profilometer after loading. Datasets were analyzed using Kruskal-Wallis test followed by Mann-Whitney tests with the Bonferroni correction (α = .05). RESULTS. Twenty-three samples passed the test; one LD sample fractured after 770,474 cycles. Post-load RTV varied significantly depending on the hybridabutment material (P = .020). Group P had a significantly higher median of post-load RTVs than group Z (16.5 and 14.3 Ncm, respectively). Groups LD and P showed minor signs of wear, and group Z showed a more pronounced wear pattern. While evaluating compressive side affected area roughness of titanium bases, lower medians were shown in group LD (Ra 0.16 and Rq 0.22 ㎛) and group P (Ra 0.16 and Rq 0.23 ㎛) than in group Z (Ra 0.26 and Rq 0.34 ㎛); significant differences were found only among the unaffected surface and group Z. CONCLUSION. The hybrid abutment material influences the post-load RTV. Group Z had a more pronounced wear pattern on the compressive side of titanium base; however, the surface roughness was not statistically different among the hybridabutment groups.

• 대한치과보철학회지
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• 제46권3호
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• pp.246-254
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• 2008

STATEMENT OF PROBLEM: The cast abutment has advantages of overcoming angulation problem and esthetic problem. However, when a gold-machined UCLA abutment undergoes casting, the abutment surfaces in contact with the implant may change. PURPOSE: The purpose of this study was to compare the detorque values of prefabricated machined abutments with gold-premachined cast-on UCLA abutments before and after casting in two types of internal implant-abutment connection systems: (1) internal hexagonal joint, (2) internal octagonal joint. Furthermore, the detorque values of two implant-abutment connection systems were compared. MATERIALS AND METHODS: Twenty internal hexagonal implants with an 11-degree taper and twenty internal octagonal implants with an 8-degree taper were acquired. Ten prefabricated titanium abutments and ten gold-premachined UCLA abutments were used for each systems. Each abutment was torqued to 30 N㎝ according to the manufacturer's instructions and detorque value was recorded. The detorque values were measured once more, after casting with gold alloy for UCLA abutment, and preparation for titanium abutments. Group means were calculated and compared using independent t-test and paired t-test (${\alpha}$=0.05). RESULTS: The results were as follows: 1. The detorque values between titanium abutments and UCLA-type abutments showed significant differences in internal octagonal implants (P<0.05), not in internal hexagonal implants (P>0.05). 2. In comparison of internal hexagonal and octagonal implants, the detorque values of titanium abutments had significant differences between two connection systems on the initial analysis (P<0.05), not on the second analysis (P>0.05) and the detorque values of UCLA-type abutments were not significantly different between two connection systems (P>0.05). 3. The detorque values of titanium abutments and UCLA-type abutments decreased significantly on the second analysis than the initial analysis in internal hexagonal implants (P<0.05), not in internal octagonal implants (P>0.05). CONCLUSION: Casting procedures of UCLA-type abutments had no significant effect on screw loosening in internal implant-abutment connection systems, and UCLA-type abutments showed higher detorque values than titanium abutments in internal octagonal implants.