Jens Langhoff

Comparison of chemically and pharmaceutically modified titanium and zirconia implant surfaces in dentistry: a study in sheep

Advanced surface modifications and materials were tested on the same implant geometry. Six types of dental implants were tested for osseointegration after 2, 4 and 8 weeks in a sheep pelvis model. Four titanium implant types were treated with newly developed surface modifications, of which two were chemically and two were pharmacologically modified. One implant was made of zirconia. A sandblasted and acid-etched titanium surface was used as reference. The chemically modified implants were plasma-anodized or coated with calcium phosphate. The pharmacological coatings contained either bisphosphonate or collagen type I with chondroitin sulphate. The implants were evaluated using macroscopic, radiographic and histomorphometric methods. All implants were well osseointegrated at the time of death. All titanium implants had similar bone implant contact (BIC) at 2 weeks (57-61%); only zirconia was better (77%). The main BIC increase was between 2 and 4 weeks. The pharmacologically coated implants (78-79%) and the calcium phosphate coating (83%) showed similar results compared with the reference implant (80%) at 8 weeks. There were no significant differences in BIC. Compared with previous studies the results of all implants were comparatively good.

An Ultrasound Assisted Anchoring Technique (BoneWelding® Technology) for Fixation of Implants to Bone – A Histological Pilot Study in Sheep

The BoneWelding® Technology offers new opportunities to anchor implants within bone. The technology melted the surface of biodegradable polymer pins by means of ultrasound energy to mould material into the structures of the predrilled bone. Temperature changes were measured at the sites of implantation in an in vitro experiment. In the in vivo part of the study two types of implants were implanted in the limb of sheep to investigate the biocompatibility of the method. One implant type was made of PL-DL-lactide (PLA), the second one was a titanium core partially covered with PLA. Healing period was 2 and 6 months, with 3 sheep per group. Bone samples were evaluated radiologically, histologically and histomorphometrically for bone remodeling and inflammatory reactions. Results demonstrated mild and short temperature increase during insertion. New bone formed at the implant without evidence of inflammatory reaction. The amount of adjacent bone was increased compared to normal cancellous bone. It was concluded that the BoneWelding® Technology proved to be a biocompatible technology to anchor biodegradable as well as titanium-PLA implants in bone.

Does surface anodisation of titanium implants change osseointegration and make their extraction from bone any easier

OBJECTIVES Titanium implants have a tendency for high bone-implant bonding, and, in comparison to stainless steel implants are more difficult to remove. The current study was carried out to evaluate, i) the release strength of three selected anodized titanium surfaces with increased nanohardness and low roughness, and ii) bone-implant bonding in vivo. These modified surfaces were intended to give improved anchorage while facilitating easier removal of temporary implants. MATERIAL AND METHODS The new surfaces were referenced to a stainless steel implant and a standard titanium implant surface (TiMAX). In a sheep limb model, healing period was 3 months. Bone-implant bonding was evaluated either biomechanically or histologically. RESULTS The new surface anodized screws demonstrated similar or slightly higher bone-implant-contact (BIC) and torque release forces than the titanium reference. The BIC of the stainless steel implants was significant lower than two of the anodized surfaces (p = 0.04), but differences between stainless steel and all titanium implants in torque release forces were not significant (p = 0.06). CONCLUSION The new anodized titanium surfaces showed good bone-implant bonding despite a smooth surface and increased nanohardness. However, they failed to facilitate implant removal at 3 months.