Previous studies have suggested that implants of allogenic demineralized dentin might improve bone regeneration and healing in the treatment of infrabony periodontal defects. In order to make a clinical evaluation of this possibility, the material was inserted into 14 infrabony defects in 10 patients undergoing a new attachment operation. Twelve defects in 12 patients served as controls. In half of these cases no grafting material was used and the remaining six defects were filled with autogenous cancellous bone from the jaw. The defects were classified as two-wall and combined three- and two-wall bony defects. Probing from a fix point and periodic identical X-rays were performed before the surgical treatment and 12 months postoperatively. During healing no clinical signs of rejection of the dentin implants were observed, but the soft tissue healing was delayed, probably due to a slow resorption of the dentin implants. After 12 months no statistically significant difference was found between test and control groups regarding the mean coronal displacement of the bottom of the pocket. No conclusive evidence regarding the capacity of allogenic demineralized dentin to induce new connective tissue attachment could be drawn from the present study, but the clinical results, combined with the fact that the dentin implants are time consuming to produce, indicate that this material is not suitable for the treatment of infrabony periodontal defects.