Early bone formation adjacent to rough and turned endosseous implant surfaces

Early bone formation adjacent to rough and turned endosseous implant surfaces
August 2004
Ingemar Abrahamsson 1 , Tord Berglundh 1 , Elena Linder 1 , Niklaus P. Lang 1 and Jan Lindhe 1
Clinical Oral Implants Research
Volume 15 Issue 4 Page 381 - August 2004
Abstract
Objective: To validate a proposed model (Berglundh et al. 2003) and to evaluate the rate and degree of osseointegration at turned (T) and sand blasted and acid etched (SLA) implant surfaces during early phases of healing.
Material and methods: The devices used for the study of early healing had a geometry that corresponded to that of a solid screw implant with either a SLA or a T surface configuration. A circumferential trough had been prepared within the thread region (intra-osseous portion) that established a geometrically well-defined wound chamber. Twenty Labrador dogs received totally 160 experimental devices to allow the evaluation of healing between 2 h and 12 weeks. Both ground and decalcified sections were prepared from mesial/distal and buccal/lingual device sites. Histometric and morphometric analyses of the ground sections and morphometric analysis of the tissue components in decalcified sections were performed.
Results: The ground sections provided an overview of the various phases of tissue formation, while the decalcified, thin sections enabled a more detailed study of events involved in bone tissue modeling and remodeling for both SLA and T surfaces. The initially empty wound chamber became occupied with a coagulum and a granulation tissue that was replaced by a provisional matrix. The process of bone formation started already during the first week. The newly formed bone present at the lateral border of the cut bony bed appeared to be continuous with the parent bone, but on the SLA surface woven bone was also found at a distance from the parent bone. Parallel-fibered and/or lamellar bone as well as bone marrow replaced this primary bone after 4 weeks. In the SLA chambers, more bone-to-device contact, more initial woven bone and earlier lamellar bone formation was found than in the T chambers.
Conclusion: Osseointegration represents a dynamic process both during its establishment and its maintenance. While healing showed similar characteristics with resorptive and appositional events for both SLA and T surfaces, the rate and degree of osseointegration were superior for the SLA compared with the T chambers.

Recently, a model system for studying the healing responses of endosseous oral implants was presented (Berglundh et al. 2003). A solid screw implant was used and designed with a circumferential trough that established a geometrically well-defined wound compartment. A large number of such experimental devices were placed in experimental animals and healing was allowed for periods ranging from 2 h to 12 weeks. This model disclosed that osseointegration represented a dynamic process both during its establishment and its maintenance.
It has been claimed that implants with a roughened surface may promote the rate and degree of osseointegration (Buser et al. 1991; Cochran et al. 1996, 1998). However, the sequence of events during the early phases of tissue integration has not been assessed for turned and surface modified implants.
The aim of the present experiment was to validate the model proposed and to evaluate the rate and degree of osseointegration at turned and sand blasted and acid etched (SLA) implant surfaces during early phases of healing.

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