医学资料-冠高比率的重要性在牙科植入物断裂强度不同的连接设计_体外研究.pdfVIP

Importance of Crown Height Ratios in Dental Implants on the Fracture Strength of Different Connection Designs: An In Vitro Study Sergio Alexandre Gehrke, DDS, PhD*† ABSTRACT Purpose: The aim of the present in vitro study was to assess the resistance to static fatigue of implants with different connections at various crown heights. Materials and Methods: Sixty conical implants and 60 abutments were used with the smallest diameters available for each model. Three groups (n = 20) were established based on the implant connections: Morse taper Ø3.50 mm (group 1), external hexagon Ø3.50 mm (group 2), and internal hexagon Ø3.50 mm (group 3). Four crown heights were tested: h = 8 mm, h = 10 mm, h = 12 mm, and h = 14 mm. All groups were subjected to quasi-static loading at a 30° angle to the 1 2 3 4 implant axis in a universal testing machine. Results: The mean fracture strengths for group 1 were 1524 N (h ), 1469 N (h ), 750 N (h ), and 729 N (h ). Those for group 1 2 3 4 2 were 1504 N (h ), 814 N (h ), 491 N (h ), and 325 N (h ). Those for group 3 were 1543 N (h ), 672 N (h ), 403 N (h ), and 1 2 3 4 1 2 3 390 N (h4 ). Conclusions: Resistance to loading decreases significantly with increasing crown height, and the connection design can affect the performance. KEY WORDS: abutment, crown height, dental implant, fracture mode, fracture strength, implant connection INTRODUCTION dimensions3 for a given region of the maxilla or Implants are common tools for the replacement of mandible,4,5 as well as inadequate