Use of porous hydroxylapatite blocks for augmentation of atrophic mandibles

A clinical study of the use of porous blocks of hydroxylapatite (Interpore 200) for augmentation of atrophic residual mandibular ridges was performed. Fifteen patients each had three preoperatively customized blocks placed. They were then examined clinically and radiographically for at least 2 years. Six patients had skin-graft vestibuloplasties performed over the blocks 3 months after implantation; dentures were made for 11 of the patients. No clinical or radiographic evidence of migration or resorption of the blocks was found; however, all 15 patients suffered complications. Eleven developed ulcerations over the blocks with persistent exposure, six had suture line dehiscence leading to exposure, two infections occurred, and two patients developed chronic pain in the area of block insertion. The skin graft took only partially in all patients undergoing subsequent vestibuloplasties. To date, 37 of the original 45 blocks have required complete removal. Histologic examination of removed blocks has revealed partial filling of the pores with lamellar bone. The use of blocks of porous hydroxylapatite to reconstruct atrophic residual mandibular ridges was found to have an unacceptably high rate of failure and the ability to sustain an overlying split-thickness skin graft was unpredictable.