• 대한치과보철학회지
• /
• 제44권1호
• /
• pp.73-84
• /
• 2006

The importance of soft tissue response to implant abutments has become one of the major issues in current implant dentistry. To date, numerous studies have emphasized on maintaining connective tissue barriers in quantity, as well as in quality fir the long term success of dental implants. The cells mainly consisting the soft tissue around dental implants are fibroblasts and epithelial cells. The mechanism of the fibroblasts adhesions to certain substrata can be explained by the 'focal adhesion' theory. On the other hand, epithelial cells adhere tn the substratum via hemidesmosomes. The typical integrin-mediated adhesions of cells to certain matrix are called 'cell-matrix adhsions'. The focal adhesion complex of fibroblasts, in relation to the cell-matrix adhsions, consists of the extracellular matrix(ECM) such as fibronectin, the transmembrane proteins such as integrins, the intracellular cytoplasmic proteins such as vinculin, talin, and more, and the cytoskeletal structures such as filamentous actin and microtubules. The mechanosensory function of integrins and focal adhesion complexes are considered to play a major role in the cells adhesion, migration, proliferation, differentiation, division, and even apoptosis. The '3-D matrix adhesions' defined by Cukierman et al. makes a promising future for the verification of the actual process of the cell-matrix adhesions in vivo and can be applied to the field of implant dentistry in relation to obtaining strong soft tissue attachment to the implant abutments.

• The Journal of Advanced Prosthodontics
• /
• 제8권1호
• /
• pp.21-29
• /
• 2016

This in vitro study investigated and compared the durability and retention of three types of attachments. MATERIALS AND METHODS. Three commercially available attachments were investigated: $Clix^{(R)}$, Dalbo-$Plus^{(R)}$ and $Locator^{(R)}$. In total, 72 samples of these attachments were placed in the acrylic resin forms and subjected to mechanical testing (5400 cycles of insertion and removal) over the respective ball or Locator abutments immersed in artificial saliva at pH 7 and $37^{\circ}C$. The abutments were placed at angulations of $0^{\circ}$, $10^{\circ}$ and $20^{\circ}$. The retention force was recorded at the beginning and after 540, 1080, 2160, 3240, 4320 and 5400 insertion-removal cycles. RESULTS. The results revealed that there were significant differences in the average values of the insertion/removal force due to angulation ($F_{(2.48)}=343619$, P<.05) and the type of attachment ($F_{(7.48)}=23.220$, P<.05). CONCLUSION. Greater angulation of the abutments was found to influence the retention capacity of the attachments, and the fatigue test simulating 5 years of denture insertion and removal did not produce wear in the metal abutments.

• 대한치과보철학회지
• /
• 제56권4호
• /
• pp.278-286
• /
• 2018

목적: 인조골에 동일한 조건으로 식립한 임플란트에 대하여 타진방식의 임플란트 안정성 측정기기인 Periotest와 AnyCheck을 사용하여 안정성 수치를 측정함에 있어서, healing abutment의 높이와 타진각도의 변화에 따른 각 측정기기의 안정성 수치 차이를 조사하는 것이다. 재료 및 방법: 총 60개의 임플란트를 주문제작한 인조골 블록에 식립하고 2, 3, 4, 5 mm 높이의 healing abutment를 각각 15개씩 네 그룹으로 나누어 체결하였으며, 각각 식립 토크, implant stability test, Periotest value를 측정했다. 임플란트 식립 시 45 - 55 Ncm의 토크를 유지하였다. 임플란트 장축에 수직인 지면을 기준으로, implant stability test는 AnyCheck을 사용하여 $0^{\circ}$, $30^{\circ}$의 기울기로 측정했으며 Periotest value는 Periotest M을 사용하여 $0^{\circ}$, $30^{\circ}$의 기울기로 측정하였다. 측정값은 통계적으로 비교 분석하였다. 결과: 식립 토크는 그룹 간 통계적 유의차가 없었다. AnyCheck과 Periotest M으로 측정했을 때, healing abutment의 높이가 증가할수록 안정성 수치가 낮게 측정되었다. 또한 AnyCheck과 Periotest M을 $0^{\circ}$와 $30^{\circ}$ 기울기로 측정 시 $0^{\circ}$로 측정한 그룹에서 안정성 수치가 더 낮게 측정되었다. 결론: 임플란트의 안정성 수치를 타진방식으로 측정할 때에는 healing abutment 높이와 타진각도의 변화에 따른 차이를 고려하여 측정해야 표준화된 평가를 할 수 있으며, 이에 대한 더욱 세밀한 사용법을 인지할 필요가 있다고 사료되었다.

• Journal of Periodontal and Implant Science
• /
• 제45권4호
• /
• pp.152-155
• /
• 2015

Purpose: This case report discusses the effect of a root submergence technique on preserving the periodontal tissue at the pontic site of fixed dental prostheses in the maxillary anterior aesthetic zone. Methods: Teeth with less than ideal structural support for fixed retainer abutments were decoronated at the crestal bone level. After soft tissue closure, the final fixed dental prostheses were placed with the pontics over the submerged root area. Radiographic and clinical observations at the pontic sites were documented. Results: The submerged roots at the pontic sites preserved the surrounding periodontium without any periapical pathology. The gingival contour at the pontic site was maintained in harmony with those of the adjacent teeth, as well as the overall form of the arch. Conclusions: The results of this clinical report indicate that a root submergence technique can be successfully applied in pontic site development with fixed dental prostheses, especially in the maxillary anterior esthetic zone.

• 품질경영학회지
• /
• 제36권2호
• /
• pp.59-66
• /
• 2008

Dental implant has recently become one of the most viable treatment options for regaining the oral function and dental aesthetics compared with conventional fixed or removable dentures. Dental implants vary in material, dimensions, geometries, surface properties, and interface geometries. It has been reported that there has been a proliferation of manufacturers who produce implants using various materials and surface treatments, and the dentist needs to select from over 2,000 different dental implants and abutments in a specific treatment situation. Unfortunately, however, no metrics have been specifically identified for the purpose of quality assessment and selection of an appropriate dental implant. This study aims to provide practical guidelines for quality assessment of dental implant based on clinical data. Like other medical devices and materials, the superiority related to specific characteristics of the dental implant needs to be verified through extensive clinical studies. The procedures of clinical monitoring for dental implants have been proposed along with a case study to exemplify the usefulness of clinical monitoring for the purpose of continuous quality improvement in medical industry.

• 대한치과의사협회지
• /
• 제51권12호
• /
• pp.643-649
• /
• 2013

The aim of this study was to achieve the healing of peri-implantitis defects and the hard tissue regeneration using the augmentation of a xenograft on defect site. Two patients were treated with the surgical approach. With a full muco-periosteal flap elevation, the implant surfaces were exposed and taken the debridement of granulation tissue around the abutment. Each surface of the abutments was prepared with the air-abrasive device (PerioFlow$^{(R)}$) for decontamination. Bovine-derived bone mineral (Bio-Oss collagen$^{(R)}$) was then used to fill the defects, and no membrane was placed on the grafting site. Radiographs and clinical photo was taken to compare from baseline status. Within the limits of the present case, this case shows the significance of the surgical treatment of peri-implantitis. And this also verifies the stability of bovine-derived bone mineral and effectiveness of Air-abrasive device (PerioFlow$^{(R)}$).

• 대한치과보철학회지
• /
• 제42권6호
• /
• pp.664-670
• /
• 2004

Statement of problem. One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection. Purpose. The purpose of this study was to examine the changes of detorque values of abutment screws with external connection in different abutment heights. Materials and methods. After cyclic loading on three different abutment heights, detorque values were measured. Abutments were retained with titanium abutment screws tightened to 30 Ncm (30.5 kgmm) with digital torque gauge as recommended by the manufacturer. Replacing abutments, implants and titanium abutment screws with new ones at every measurement, initial detorque values were measured six times. In measuring de torque values after cyclic loading, Avana Cemented Abutments of 4.0 mm collar, 7.0 mm height (Osstem Co., Ltd., Seoul, Korea) were used with three different lengths of 5.0, 8.0, 11.0 mm. Shorter abutments were made by milling of 11.0 mm abutment to have the same force-exercised area of 4.5 mm diameter. Sine curve force (20N-320N, 14Hz) was applied, and detorque values were measured after cyclic loading of 2 million times by loading machine. Detorque values of initial and after-loading were measured by digital torque gauge. One-way ANOVA was employed to see if there was any influence from different abutment heights. Results. The results were as follows: 1. The initial detorque value was 27.8$\pm$0.93 kgmm, and the ratio of the initial detorque value to the tightening torque was 0.91(27.8/30.5). 2. Measured detorque values after cyclic loading were declined as the height of the abutment increased, that was, 5.0 mm; 22.3$\pm$0.82 kgmm, 8.0 mm; 21.8$\pm$0.93 kgmm, and 11.0 mm; 21.3$\pm$0.94 kgmm. 3. One-way ANOVA showed no statistically significant differences among these (p>0.05). 4. Noticeable mobility at the implant-abutment interface was not observed in any case after cyclic loading at all.

• The Journal of Advanced Prosthodontics
• /
• 제10권5호
• /
• pp.388-394
• /
• 2018

PURPOSE. To measure axial displacement of different implant-abutment connection types and materials during screw tightening at the recommended torque by using a contact scanner for two-dimensional (2D) and three-dimensional (3D) analyses. MATERIALS AND METHODS. Twenty models of missing mandibular left second premolars were 3D-printed and implant fixtures were placed at the same position by using a surgical guide. External and internal fixtures were used. Three implant-abutment internal connection (INT) types and one implant-abutment external connection (EXT) type were prepared. Two of the INT types used titanium abutment and zirconia abutment; the other INT type was a customized abutment, fabricated by using a computer-controlled milling machine. The EXT type used titanium abutment. Screws were tightened at $10N{\cdot}cm$, simulating hand tightening, and then at the manufacturers' recommended torque ($30N{\cdot}cm$) 10 min later. Abutments and adjacent teeth were subsequently scanned with a contact scanner for 2D and 3D analyses using a 3D inspection software. RESULTS. Significant differences were observed in axial displacement according to the type of implant-abutment connection (P<.001). Vertical displacement of abutments was greater than overall displacement, and significant differences in vertical and overall displacement were observed among the four connection types (P<.05). CONCLUSION. Displacement according to connection type and material should be considered in choosing an implant abutment. When adjusting a prosthesis, tightening the screw at the manufacturers' recommended torque is advisable, rather than the level of hand tightening.

• The Journal of Advanced Prosthodontics
• /
• 제9권2호
• /
• pp.99-103
• /
• 2017

PURPOSE. The purpose of this study was to achieve more retention and stability and to delay or prevent screw loosening. MATERIALS AND METHODS. Twenty implants (Implantium 3.4 mm, Dentium, Seoul, Korea) were divided into 2 groups (n = 20). In the first group, an adhesive material was applied around the screw of the abutments (test group). In the second group, the screws are soaked in saliva (control group). All the screws were torqued under 30 N/cm, Then, the samples were gone through a cyclic fatigue loading process. After cyclic loading, we detorqued screws and calculated detorque value. RESULTS. In comparison with the control group, all the implant screws in the test group were smeared with the adhesive material, showing significant higher detorque value. CONCLUSION. There are significantly higher detorque values in the group with adhesive. It is recommended to make biocompatible adhesive to reduce screw loosening.

• 대한심미치과학회지
• /
• 제3권1호
• /
• pp.44-50
• /
• 1995

Abutment dies which resemble the actual size and shape of crown abutment is essential in most of the research area of fixed prosthodontics like marginal accuracy, crown seating, behavior of luting agent and so on. Seeing the large portion of research is done with round shaped dies in different size and cone angles, the necessity of research on the crown abutment is self-evident. 500 molar abutments were collected randomly through the commercial dental laboratoy, regrdless of their position in the dental arch, sex, and age. The measurements of 22 points of a die were done, and the results were as fogbows : 1. The height of the molar dies was $3.9{\pm}1.2mm$ 2. The bucco-lingual width was $8.9{\pm}1.2mm$ at the base, and $7.4{\pm}1.2mm$ at the occlusal. 3. The desio-sistal width was $8.2{\pm}1.2mm$ at the base, and $7.0{\pm}1.3mm$ at the occlusal.