New formation of periodontal tissues around titanium implants in a novel dentin chamber model Ates Parlar Dieter D. Bosshardt Berrin U ¨ nsal Deniz C ¸ etiner Cenk Haytac ¸ Niklaus P. Lang Authors’ affiliations: Ates Parlar, Berrin U ¨ nsal, Deniz C ¸ etiner, Department of Periodontology, Faculty of Dentistry, Gazi University, Ankara, Turkey Dieter D. Bosshardt, Niklaus P. Lang, Department of Periodontology and Fixed Prosthodontics, School of Dental Medicine, University of Berne, Berne, Switzerland Cenk Haytac ¸ , Department of Periodontology, Faculty of Dentistry, C ¸ ukurova University, Adana, Turkey Correspondence to: Dr Ates Parlar Department of Periodontology Faculty of Dentistry Gazi University 8, Cadde Emek TK-06630 Ankara Turkey Tel.: þ 90 312 441 5984 Fax: þ 90 312 441 6680 e-mail: Ates.parlar@superonline.com Key words: bone, cementum, implants, periodontal ligament, regeneration Abstract: Direct bone-to-implant contact, defined as ‘osseointegration’, is considered most optimal for long-term stability and survival of dental implants. However, the possibility of the formation of a tooth-like attachment apparatus around implants has also been demonstrated. The purpose of this study was to explore the formation of periodontal tissues around titanium implants using a novel and unique experimental model. After resection of the crowns of the maxillary canine teeth in nine mongrel dogs, the roots were hollowed to a depth of 5 mm leaving a thin dentinal wall. Slits were prepared in the cavity wall to create passages from the chamber to the periodontal ligament area. A custom- made, titanium implant was placed into the center of each chamber. Machined, titanium plasma sprayed (TPS) and sand blasted with large grit and acid attacked (SLA) surfaces were used. A collagen barrier was placed over the submerged chamber. Following 4 months of healing, jaw sections were processed for histology. Newly formed periodontal ligament, alveolar bone, and root cementum filled the space between the implant and the wall of the chamber. Ingrown bone was neither in contact with dentin nor with the implant. Thus, an interposed soft connective tissue layer was present. Healing by fibrous encapsulation was observed around most implants. However, cellular cementum was deposited on one TPS and one SLA implant and on the dentinal walls of the chamber. This study shows a remarkable capacity for new periodontal tissue formation at a site where no such tissues ever existed. Maintenance of original periodontal tissue domains most likely prevented osseointegration of the implants. The cementum layer deposited on two implants was likely formed through cementoconductivity rather than by differentiation of periodontal ligament cells upon contact with the implant surface. Currently, direct bone-to-implant surface contact is considered the optimal healing response around endosseous implants and is defined as ‘osseointegration’ (Schroeder et al. 1981; Bra ˚nemark et al. 1985). This type of ankylotic anchorage of dental im- plants into jawbone has been extensively studied and high survival rates of such implants have been reported based on long-term surveys (Adell et al. 1981, 1990; Albrektsson et al. 1988). Osseointe- grated implants are rigidly connected to the bone via an intimate contact of bone tissue to the implant surface (Schroeder et al. 1981, 1991; Bra ˚nemark et al. 1985). The character of the tissues around a titanium implant and the nature of the tissue attach- ment to the implant surface influence the biomechanical responses of this integra- tion. Unlike natural teeth, dental implants lack cementum and periodontal ligament. Because of this structural difference, func- tional differences also exist between teeth and osseointegrated implants. For example, Copyright r Blackwell Munksgaard 2005 Date: Accepted 12 July 2004 To cite this article: Parlar A, Bosshardt DD, U ¨ nsal B, C ¸ etiner D, Haytac ¸ C, Lang NP. New formation of periodontal tissues around titanium implants in a novel dentin chamber model. Clin. Oral Impl. Res. 16, 2005; 259–267 doi: 10.1111/j.1600-0501.2005.01123.x 259