Marginal Tissue Response to Different Implant Neck Design

Early clinical reports on osseointegration of dental implants have reported success rates of 81% in maxilla and 91% in mandible after 15 years, with marginal bone loss of 1.5 mm in the first year and approximately 0.1 mm annually from there after. This satisfied the success criteria which were published in the years to follow; they were clinical stability, in function without any symptoms and with minimal bone resorption of less than 0.2 mm annually after the first year of the implantation. The success of osseointegration of dental implant has been repeatedly demonstrated by numerous clinical studies in different implant designs, prosthodontic design and clinical situations which the implants have been applied. The improvements in longevity of dental implants need to review on the success criteria of the marginal bone loss, of approximately 0.2 mm annually after the first year. The United States National Institutes of health consensus conference in 1988 have shown their concern of stable marginal bone level and advised clinical studies to have longitudinal evaluation of bone level measurements for an accurate implant evaluation. Aesthetics, as much as function, play an important role in patient satisfaction of implant dentistry. The expected demands have led the clinician to increase their understanding and skill in implantation and restoration of the implant prosthesis. In conjunction with these attempts, improvements in the design, texture and surface chemistry of the implants have been made. Many of these are commercially available although some may only have had a short history of commercial life. The implant neck design is one of these areas of development. Micro-textured and the macro-textured surfaces were explored. These designs mainly aimed to enhance the stability of interface for both soft and hard tissue and minimise the marginal bone reduction in the first year of implantation. An animal study by Abrahamsson et al. has shown the marginal bone level differences between three different implant designs had no statistical significance. However, all three implant designs had turned surface at hard and soft tissue interface. Astrand and his colleagues compraired rough neck surfaced neck implant and turned surface over 5 years. The measurements were better in the rough surfaced neck implant but there was no statistical significance. Despite after these results, finite element studies have shown that the retentive form at the coronal portion of fixture have favourably reduced the peak interfacial shear stress at the margin and more stresses were present at the lower part of the implant. On the micro texture implant, retention of hard tissues with the micro-textured surfaces was observed. The aim of the present study was to investigate the influence of three different implant neck designs on bone and soft tissue interface region in dogs at 8 and 12 weeks after implantation.