• 대한치과보철학회:학술대회논문집
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• 2002.11a
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• pp.96-97
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• 2002

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.2
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• pp.245-252
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• 1996

The purpose of this study was to develop the implant which has superior stress distribution and primary stability to others by using Instron test and finite element method. The model used in the experiment were cylinder type implant, tapered screw type implant, screw type implants. Recognizing that the number of samples were small and the lack of applying press-fit conditions to the cylinder type, we can make the following conclusions.

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.396-403
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• 2016

PURPOSE. Early loading of implant can be determined by excellent primary stability and characteristic of implant surface. The implant system with recently improved surface can have load application 4-6 weeks after installing in maxilla and mandible. This study evaluated the effect of healing period to the stability of hydrophilic tapered-type implant at maxillary posterior area. MATERIALS AND METHODS. This study included 30 patients treated by hydrophilic tapered-type implants (total 41 implants at maxilla) and classified by two groups depending on healing period. Group 1 (11 patients, 15 implants) was a control group and the healing period was 12 weeks, and Group 2 (19 patients, 26 implants) was test group and the healing period was 6 weeks. Immediately after implant placement, at the first impression taking, implant stability was measured using Osstell Mentor. The patients also took periapical radiographs after restoration delivery, 12 months after restoration and final followup period. The marginal bone loss around the implants was measured using the periapical radiographs. RESULTS. All implants were survived and success rate was 97.56%. The marginal bone loss was less than 1mm after 1 year postoperatively except the one implant. The stabilities of the implants were not correlated with age, healing period until loading, insertion torque (IT), the diameter of fixture and the location of implant. Only the quality of bone in group 2 (6 week) was correlated with the stability of implant. CONCLUSION. Healing period of 6 weeks can make the similar clinical prognosis of implants to that of healing period of 12 weeks if bone quality is carefully considered in case of early loading.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.47-57
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• 2010

An undisturbed healing process without micromotion at the implant-bone interface is essential for achievement of osseointegration of dental implant. Therefore, initial stability was advocated as prerequisite for successful clinical outcome. Adequate bone quality and quantity were important to achieve initial stability and to prevent early failures. However there were few published data available regarding the effect of design change in implant geometry on initial stability of the implants. The purpose of the current study was to assess the initial stability of various designs of implants when placed into artificial bone materials of varying qualities and shapes of insertion holes. Within the scope of this study, the following results were drawn. Bone quality was major importance to achieve initial stability. Initial stability was higher on GS II which had additional design feature of double thread. With a tapered design of implant such as GS III showed a higher initial stability than straight one. An insertion hole with the similar shape of implant would lead to reduce a compression force on cortical bone and enhance a bone anchorage on cancellous bone.

• 대한치주과학회:학술대회논문집
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• 2005.11a
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• pp.68-68
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• 2005

• Journal of Periodontal and Implant Science
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• v.40 no.5
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• pp.239-243
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• 2010

Purpose: The purpose of this study was to evaluate the effects of implant shape and bone preparation on the primary stability of the implants using resonance frequency analysis. Methods: Sixty bovine rib blocks were used for soft and hard bone models. Each rib block received two types of dental implant fixtures; a straight-screw type and tapered-screw type. Final drilling was done at three different depths for each implant type; 1 mm under-preparation, standard preparation, and 1 mm over-preparation. Immediately after fixture insertion, the implant stability quotient (ISQ) was measured for each implant. Results: Regardless of the bone type, the ISQ values of the straight-screw type and tapered-screw type implants were not significantly different (P>0.05). Depth of bone preparation had no significant effect on the ISQ value of straight-screw type implants (P>0.05). For the tapered-screw type implants, under-preparation significantly increased the ISQ value (P<0.05), whereas overpreparation significantly decreased the ISQ value (P<0.05). Conclusions: Within the limitations of this study, it is concluded that bone density seemed to have a prevailing effect over implant shape on primary stability. The primary stability of the tapered-screw type implants might be enhanced by delicate surgical techniques.

• Journal of Korean Dental Science
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• v.3 no.1
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• pp.11-16
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• 2010

Objective : This prospective study sought to verify the stability of three types of short implants measuring 7mm or less. Materials and methods : Implants measuring 7mm or less were placed in patients at multicenter dental clinics in Korea, China, Taiwan, and Singapore. Initial stability, intraoperative and postoperative complications, crestal bone loss, and survival rate of the implant were prospectively evaluated. Results : The primary stability of a 6-mm implant was lower than that of a 7-mm implant. The marginal bone loss of short implants measuring less than 7mm was minimal. Complications such as wound dehiscence, implant mobility, and peri-implant mucositis developed, and these were associated with initial implant failure. The short-term survival rate of 6-mm implant was 93.7%, and that of 7-mm implant, 96.6%. Conclusion : Short implant for the mandible with insufficient height for the residual ridge can be selectively used. Poor primary stability and wound dehiscence can cause osseointegration failure and alveolar bone loss.

• Structural Engineering and Mechanics
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• v.74 no.4
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• pp.567-576
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• 2020

Considerable controversy surrounds the choice of the best abutment type for implant prosthetics. The two most common structures are hex and non-hex abutments. The non-hex abutment typically furnishes a larger contact area between itself and the implant than that provided by a hex structure. However, when a hex abutment is loaded, the position of its contact area may be deeper than that of a non-hex abutment. Hence, the purpose of this study is to determine the different biomechanical behaviors of an internal bone-level implant based on the abutment type-hex or non-hex-and clinical crown length under static and cyclic loadings using finite element analysis (FEA). The hex structure was found to increase the implant and abutment stability more than the nonhex structure among several criteria. The use of the hex structure resulted in a smaller volume of bone tissues being at risk of hypertrophy and fatigue failure. It also reduced micromovement (separation) between the implant components, which is significantly related to the pumping effect and possible inflammation. Both static and fatigue analyses, used to examine short- and long-term stability, demonstrated the advantages of the hex abutment over the non-hex type for the stability of the implant components. Moreover, although its impact was not as significant as that of the abutment type, a large crown-implant ratio (CIR) increased bone strain and stress in the implant components, particularly under oblique loading.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.6
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• pp.345-351
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• 2016

Objectives: This study compared the impact of implant surface treatment on the stability and osseointegration of implants in dog mandibles. Materials and Methods: Six adult dogs received a total of 48 implants that were prepared using four different surface treatments; resorbable blast media (RBM), hydroxyapatite (HA), hydrothermal-treated HA, and sand blasting and acid etching (SLA). Implants were installed, and dogs were separated into 2- and 4-week groups. Implant stability was evaluated via Periotest M, Osstell Mentor, and removal torque analyzers. A histomorphometric analysis was also performed. Results: The stability evaluation showed that all groups generally had satisfactory values. The histomorphometric evaluation via a light microscope revealed that the HA surface implant group had the highest ratio of new bone formation on the entire fixture. The hydrothermal-treated HA surface implant group showed a high ratio of bone-to-implant contact in the upper half of the implant area. Conclusion: The hydrothermal-treated HA implant improved the bone-to-implant contact ratio on the upper fixture, which increased the implant stability.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.4
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• pp.269-275
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• 2013

Purpose: The aim of this retrospective study was to evaluate the influence of implant diameter, length and placement to implant stability. Materials and methods: Total 90 implants (US II plus$^{TM}$, Osstem co, Busan, Korea) of 72 patients were determined as experimental samples. The factors of diameters(${\phi}$ 4 mm, ${\phi}$ 5 mm), lengths (10 mm, 11.5 mm, 13 mm), and implant placement (maxilla, mandible) were analyzed. The stability of the implants was measured by resonance frequency analysis (RFA) at the time of implant placement and impression taking. The difference of ISQ values according to patient's gender was evaluated by Independent t-test. ISQ values were compared between implant diameter, length and placement using one-way ANOVA and Tukey HSD test (${\alpha}=.05$). To compare ISQ values between at the time of surgery and impression taking, paired t-tests were used (${\alpha}=.05$). Results: The change of implant length did not show significant different on the ISQ value (P>.05). However, 5 mm diameter implants had higher ISQ values than 4 mm diameter implants (P<.05). Implants placed on the mandible showed significantly higher ISQ values than on the maxilla (P<.05). Conclusion: In order to increase implant stability, it is better to select the wider implant, and implants placed on mandible are possible to get higher stability than maxilla. ISQ values at impression taking showed higher implant stability than ISQ values at implant placement, it means that RFA is clinically effective method to evaluate the change of implant stability through the osseointegration. The consideration of the factors which may affect to the implant stability will help to determine the time of load applying and increase the implant success rate.