Special Print 2009 – Becker J. et al.

Background Titanium dental implants become firmly incorporated into living bone tissue by forming a bond between im- plant surface and bone. This bony anchorage is a stable structure usually maintained for a lifetime (Lekholm et al., 2006; Astrand et al., 2008). Another essential tissue component of successfully integrated dental implants is the peri-implant soft tissue. Attached to the implant surface it forms a functional barrier between oral cav- ity and alveolar bone to protect the bone from potential infiltrating contaminants of the oral environment (McKinney et al., 1984). However crestal alveolar bone at two-piece implants is typically remodelled during the first year of loading resulting in marginal bone loss that may extend to 2mm (Albrektsson et al., 1986; Smith and Zarb, 1989; Jung et al., 1996). Factors asso- ciated with this bone resorption process include inflam- mation at the implant-abutment interface (Ericsson et al., 1995; Herman et al., 2001), formation of a normal biologic width (Berglundh and Lindhe, 1996), dis- and reconnections of the abutment compromising the mucosal barrier (Abrahamsson et al., 1997), as well as apparently aspects of the implant design such as the macro-design (Zechner et al., 2004; Shin et al., 2006) and the position of the smooth-rough surface border (Hermann et al., 2000). Based on this knowledge the Research and Deve- lopment Department of CAMLOG Biotechnologies AG has systematically developed and tested design changes of the CAMLOG implants in order to improve the for- mation and maintenance of the structure of the soft and hard tissue attachment. Reduced machined surface segment First, the machined surface segment of the SCREW- LINE implant neck was significantly reduced to the Promote ® plus design, i.e. a reduction from 2.0mm to 0.4mm. The changes resulting from moving the smooth-rough surface border were analyzed in dogs for a healing period of 3 months (Schwarz et al., 2008). The data demonstrated that the new surface design effi- ciently reduced crestal bone changes. It could be con- cluded that when a native thick gingiva was available, an approximately 1 mm higher bony integration level of the implant could be accomplished without the mar- ginal epithelium reaching the micro-structured surface (Becker et al., 2006). Platform switching The second approach to minimize crestal bone changes was to use a modified implant-abutment configura- tion. This alternative design contains a reduced diam- eter of the abutment relative to the diameter of the im- plant platform (called platform switching), an optimized connection with reduced cam-grooves in height and an Preservation of crestal bone level at non-submerged CAMLOG titanium implants with standard or platform switched configuration Fig. 1 Schematic illustration of CAMLOG® SCREW-LINE Promote® plus (K-Series) implants with standard (control, left) and non matching (platform switching, right) wide body healing abutments The influence of platform switching and non-platform switching on crestal bone level changes over six months was evaluated in an experimental animal study using a new non-submerged titanium implant type (CAMLOG, K-Series). Histological data demon- strated successful integration of the implants into hard and soft tissue as well as stable crestal bone levels in both modalities.