Clinical safety and efficacy of implantation of octacalcium phosphate collagen composites in tooth extraction sockets and cyst holes

Abstract

It was demonstrated that octacalcium phosphate collagen composite achieved notable bone regeneration in bone defects in preclinical studies. On the basis of the research results, an investigator-initiated exploratory clinical trial was conducted after approval from a local Institutional Review Board. This clinical study was performed as a single-arm non-randomized intervention study. Octacalcium phosphate collagen composite was implanted into a total of 10 cases of alveolar bone defects after tooth extractions and cystectomy. Safety assessment was performed in terms of the clinical course and several consecutive laboratory examinations, and sequential radiographs were used for efficacy assessment. All participants uneventfully completed the clinical trial without major problems in their general condition. Postoperative wound swelling was observed, as also commonly seen in tooth extraction or cystectomy. Although no serious liver dysfunction, renal dysfunction, electrolyte imbalance, or abnormal urinalysis results were recognized, the number of white blood cells and C-reactive protein level temporarily increased after the operation. An increase in radiopacity in the octacalcium phosphate collagen composite-implanted site was observed in all cases. Finally, the border between the original bone and the octacalcium phosphate collagen composite-implanted site became indistinguishable. These results suggest that octacalcium phosphate collagen composite could be utilized safely in clinical situations in the future.

Keywords: Bone regeneration; bone tissue engineering; calcium phosphate; collagen.

Figure 1.

The appearance of OCP/Col disks and XRD of OCP/Col: (a) the disks were molded to 9 mm in diameter and 1 mm thick and (b) XRD patterns of OCP/Col before implantation.

Figure 2.

Macroscopic view before and after implantation of OCP/Col: (a) after tooth extraction, the extraction socket (*) was evident and (b) the disks of OCP/Col sponge were implanted into the extraction socket.

Figure 3.

Chronological change in the number of white blood cells (WBC). Although the number of WBC increased the day after surgery, it almost recovered to within the normal limits (gray zone) after 1 week, at which level it was maintained thereafter.

Figure 4.

Radiographs after OCP/Col implantation. Before the operation (pre), the impacted wisdom tooth was observed. Radiopacity was not observed in the operated region the day after the operation (1D). After 1 month (1M), the border of the extraction socket became broader and unclear. After 3 months (3M), the border of the extraction socket became almost indistinguishable, and the radiopacity in the whole extraction socket clearly increased. After 6 months (6M), a cortical bone-like structure was indicated in part of the upper border of the extraction socket. After 12 months (12M), the difference in radiopacity between the OCP/Col-implanted site and the original bone became almost indiscernible.