The healing effect of platelet-rich plasma on xenograft in peri-implant bone defects in rabbits

Abstract

Background: The association of biomaterial combined with repair factor-like platelet-rich plasma (PRP) has prospective values. Bovine-derived xenograft has been identified as an osteoconductive and biocompatible grafting material that provides osseointegration ability. PRP has become a valuable adjunctive agent to promote healing in a lot of dental and oral surgery procedures. However, there are controversies with respect to the regenerative capacity of PRP and the real benefits of its use in bone grafts. The purpose of this study was to assess the influence of PRP combined with xenograft for the repair of peri-implant bone defects.

Methods: Twelve rabbits were used in this study, and the experimental surgery with implant installation was performed simultaneously. Autologous PRP was prepared before the surgical procedure. An intrabony defect (7.0 mm in diameter and 3.0 mm deep) was created in the tibia of each rabbit; then, 24 titanium dental implants (3.0 mm in diameter and 8.5 mm long) were inserted into these osteotomy sites. Thus, a standardized gap (4.0 mm) was established between the surrounding bony walls and the implant surface. The gaps were treated with either xenograft alone (control group) or xenograft combined with PRP (experimental group). After healing for 1, 2, 3, 4, 5, and 6 weeks, the rabbits were sacrificed with an overdose of KCl solution. Two rabbits were killed at each time, and the samples including dental implants and surrounding bone were collected and processed for histological analysis.

Results: More newly formed bone and a better bone healing process were observed in control group. The histomorphometric analysis revealed that the mean percentage of bone-to-implant contact in the control group was significantly higher than that of the experimental group (25.23 vs. 8.16 %; P < 0.05, independent-simple t test, analysis of variance [ANOVA]).

Conclusions: The results indicate that in the addition of PRP to bovine-derived xenograft in the repair of bone defects around the implant, PRP may delay peri-implant bone healing.

Keywords: Bone healing; Dental implant; Platelet-rich plasma; Rabbit; Xenograft.

Fig. 1

Schematic of experiment. The schematic graph shows the length and diameter of implant fixture around the bone defect

Fig. 2

Bone-to-implant contact. The histological micrograph shows the position subjected to BIC measurement

Fig. 3

Histological sections at the second week. a Control group: defects treated with xenograft alone. b Experimental group: defects treated with xenograft and PRP. The new bone formation in the control group was observed more than the experimental group (2/3 vs. 1/3 of the gap, respectively). Original magnification ×100. H&E stain

Fig. 4

Histological sections at the fourth week. a Control group: defects treated with xenograft alone. b Experimental group: defects treated with xenograft and PRP. Newly formed bone can be observed in both groups. A limited bone-to-implant contact (blue arrows) was found in the control group. Original magnification ×100. H&E stain

Fig. 5

Histological sections at the sixth week. a Control group: defects treated with xenograft alone. b Experimental group: defects treated with xenograft and PRP. In the control group, the newly formed bone completely filled the bone gap; while in the experimental group, the newly formed bone filled 2/3 of the bone gap. Original magnification ×100. H&E stain

Fig. 6

Mean percentage of bone-to-implant contact (BIC %) in rabbit’s tibia. the xenograft and PRP group shows lower BIC than the control group (statistically significant difference, P < 0.05)