HTR polymer and sinus elevation: a human histologic evaluation

HTR (hard tissue replacement) polymer was used in a second session to perform 26 sinus floor elevations in 16 patients with dental implantation (Flexiroot, U.S.A.). A period of 6, 8, 10, or 12 months elapsed between the two operations, making it impossible to examine the tissular integration of HTR from both clinical and human histologic aspects. Following the sinus elevation, neither prolonged wound healing nor a rejection reaction was observed in any of the cases. During an 8 to 10 month period, sufficient new bone and fibrous connective tissue had grown between the HTR granules to ensure appropriate supporting tissue for the implantation. Subsequently (12 months), the HTR and the new bone became clinically increasingly harder, forming a union that was difficult to shape. HTR may be stated to be a material suitable for purposes of sinus elevation. In three cases in which the alveolar bone was originally very thin (2 to 3 mm), the resorption of this bone was observed, as a consequence of this the implantation was not performed. The resorption is explained by the inadequate blood supply that developed for surgical-technical reasons, and is not connected with the nature of the material used for the sinus elevation.