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4 SCIENCE | CLINICAL RESEARCH presented numerous X-ray images which demonstrated impressive consistency of bone level. A clear indication for the effect of Platform Switching is also given in a study in which the use of eccentrically placed abutments demonstrates less bone degeneration on the side with a higher horizontal shift than on the opposite side [9]. According to Cacaci, Platform Switching with CONELOG ® SCREW-LINE implants works best from a tissue thickness of 3.5 to 4.0 mm upwards. However, it should be noted that, according to the systematic review of the literature, the effects of numerous, also soft-tissue-related factors, are not yet known [2]. A study in animals submitted for publication by the Düsseldorf study team of Professor Jürgen Becker (University Düsseldorf, Germany) with CONELOG ® SCREW-LINE implants supports the above mentioned recommendations on insertion depth [10]. As a rule, the President of the CAMLOG Foundation therefore recommends an epi- or slightly supra- crestal position. The same as Dr. Cacaci, he views existing bone dehiscences as an indication for the sub-crestal placement of CONELOG ® SCREW-LINE implants. Becker reasons that this minimizes the bone area coming into contact with the oral environment in case of soft tissue inflammation. Avoiding abutment changes A number of animal studies and clini- cal findings support avoiding repeated abutment changes. In the above study, Professor Becker was also able to dem- onstrate that an experimental titanium abutment with micro-structured surface improves soft tissue adhesion in com- parison with machined surfaces [10]. At the same time, bone degeneration is reduced when refraining from changing abutments. Abutment changes – as well as repeated probing with detachment of the connective tissue and epithelial at- tachment during the healing phase [11] – should therefore be avoided if possible. This recommendation is put into context by a randomized study with single crowns or bridges on CONELOG ® SCREW-LINE implants in conjunction with Vario SR abutments. Professor Juan Blanco Carrión (University of Santiago de Compostela, Spain) presented preliminary results where the use of a healing cap (“1 abutment change”) showed no negative effects onbonepreservationafter one year compared with immediate final mounting of the abutment (“1 abutment 1 time”). Controls up to five years are to verify whether this observation applies long-term and whether a final immediate abutment has a preventive effect against peri-implant inflammation. A comparison of the two methods, supported by the CAMLOG Foundation and using CONELOG ® SCREW-LINE implants, was presented by Dr. Erhan Çömleko lu , lecturer at the Ege University Izmir (Turkey). Using the split- mouth design, he replaced the posterior maxillary incisors in ten patients and observed a slight gain in bone growth for the method without abutment change, whereas he observed slight bone loss for implants with repeated abutment changes (in contrast to the single change in the study by Blanco Carrión). It could prove to be clinically relevant that bone growth with the final immediate abutment in the area of the buccal bone lamella was especially pronounced (measured with DVT). With the aid of a video, Çömleko lu demonstrated that the connective tissue appeared to be very firmly attached to the abutment for the described method. Same as the findings for Platform Switching, this supports the idea that a suitable clinical protocol may reduce the risk of peri-implantitis (author's conclusion). Update timing A study on immediate implantations cited by Dr. Paul Sipos (Amstelveen, Netherlands), can also be regarded as a Prof. Jürgen Becker Dr. Erhan Çömleko lu Dr. Paul Sipos