The Effect of Different Implant Neck Designs upon Strain at Surrounding Bone

• Main Authors: Li-Ting Tseng, 曾莉婷
• Other Authors: Li-Deh Lin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/84100781582398547796

碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 101 === Objectives: During the clinical practice of implant treatment, dentists are usually bothered by facing unfavorable bone quantity and quality. The implant biomechanic characteristics become important to improve the prognosis of implant placement. Therefore, the idea of “functional surface area” was brought up to explain more about stress transfering at bone-implant interface. Unfortunately, we did not really understand the details of this area. The aim of the present study was to identify this area and how it influences the stress distribution. Methods: Two different designs of dental implants were included in this study. The sizes of Brånemark (Mk III, Sweden) implants were 3.75 or 5.0 mm in diameter and 8.5 or 10.0 mm in length. The sizes of Astra Tech (OsseoSpeed, Sweden) implants were 4.0S, 5.0S or 5.0 mm in diameter and 9.0 or 11.0 mm in length. There were two implants of each size. Each implant was embedded in a polymethyl methacrylate resin block (85 X 20 X 30 mm), simulating a maxillary edentulous region with low-density bone. Four miniature strain gauges (KFG-02-120-C1, Kyowa, Japan) was attached to each implant where the measuring points were at 1.0, 2.0, 4.0 and 5.0 mm below the platform on the external surface of the implant. A 30-degree oblique static load of 50N was applied 6 times on a Ti block (8 X 8 X 8 mm) screwed on the implant of each model and bone strains at the four measuring points were recorded. Results: All implants showed the largest mean strain value (MSV) at 1.0-mm site below the platform which was statistically higher (P < 0.05) than the other 3 measuring sites. For Brånemark implants, the largest MSV was observed in 3.75*8.5 mm implant. For Astra Tech implants, the largest MSV was observed in 4.0S*9.0 mm implant. MSV dereased when the implant length increased and when the implant diameter increased. However, difference existed between two implant designs in the effect of implant length and implant diameter on MSV. The outspreaded or microthreaded design also affected the MSV. Conclusion: Within the limitation of this in-vitro study, we concluded that MSV concentrated mostly at 2.0 mm below platform of implants in different diameters, lengths or designs. Therefore, there was a primary supporting area in peri-implant bone where received most strain from implants during loading. Well design in this area would give more benefits in stress distribution.