Platelet gel can act as a wound sealant and dural waterproofing agent. The presence of platelets and leukocytes leads to hemostatic and antimicrobial support, thereby reducing dehiscence and infection in the graft 4. In our study, pain was present in both the groups at the 1-week follow-up. In group A, only 46.7% of patients had pain compared with 80% of patients in group B. There was no pain at 1 month until the 12-month follow-up in both the groups. Pain reduction in both the groups was significant at follow-up (P=0.000). Our observation was in accordance with the study of Anitua 5,6, Man et al. 7, and Gilberto etal. 8,9, who found that there was a reduction in pain and swelling in the PRP group of patients postoperatively. This finding was also consistent with that of Mancuso et al. 10, who found a lower rate of osteitis and pain postoperatively in the patients in the PRP group.
The swelling of the patients in group A was less (73.3%) than that of the patients in group B (93.3%), and reduced significantly in the follow-up period in both the groups (P=0.000). In group B, one patient developed an infection. There was significant swelling in the patients in group B at 1 week and the reduction in swelling until the 12-month follow-up period was significant in the rest of the patients, almost similar to group A. There was about a 5.1-fold greater risk of swelling in group B (OR=5.1) and less probability of swelling in group A. The same finding was also reported by Anitua 5 and Fennis et al. 11, who evaluated the modulation of wound healing and soft tissue ingrowths in synthetic and allogenic implants with platelet gel. This finding is also in agreement with that of Man et al. 7, who reported that PRP is very effective in stopping capillary bleeding and aids hemostasis and wound healing, thereby reducing the postoperative swelling.
The healing was uneventful and there was no graft rejection in group A, whereas there was graft rejection in one patient in group B. At 1 week, the OR was 2.1, which indicates a higher risk of infection in group B. About 6.7% of the patients in group B developed an infection. This finding was in agreement with that of Green and Klink 4, who found that the platelet gel acts as a wound sealant and dural waterproofing agent and the presence of platelets and leukocytes leads to hemostatic and antimicrobial support, thereby reducing dehiscence and infection in the graft.
The radiological findings showed that the dense trabecular pattern was present in a higher percentage of patients at the 12th-month follow-up in group A (86.7%) than group B (80%), which shows that bone deposition was higher and faster in group A than in group B. This is in agreement with the observation of Lee et al.12, who concluded that at the 12-month follow-up, bone density was greater in the PRP group than in the non-PRP group in their study of alveolar clefts grafted with bone and PRP. At the 1-month follow-up, the dense–sparse pattern appeared earlier in group A (13.3%) compared with group B (6.7%). At 2 months, the dense–sparse pattern was present in a higher percentage of patients in group A (60.0%) compared with group B (40.0%), which shows that the dissolution of the graft and uptake of graft or graft maturity was higher in group A. This is almost in agreement with the study of Aghaloo et al.13. Aghaloo et al.13 observed increased tendency of bone formation at 1 and 2 months in his study on rabbit cranial defects and he observed histomorphometric and radiographic tendency toward increased bone formation with PRP 3. The decreased density of grafted material at 2 months in our study and increase in the dissolution of grafted material are in agreement with the observation of Lee et al.12, who observed a rapid decrease in the density of grafted bone in the early postoperative period and concluded that PRP may lead to higher bone density in the long postoperative period. Our findings at 1 and 2 months were in agreement with those of Kim et al., who studied the use of Bio-Oss and PRP in cranial defects and observed increased bone density on plain radiographic and computed tomography scans 14. In our study, at 1 month, the dense pattern was found in 80.0% of patients in group A compared with 86.7% of patients in group B. The same observation was made by Gerard et al. 15, who found that at 1 month, the non-PRP grafts were more dense compared with PRP grafts (P<0.05).
The higher density at 1 month is because of the graft material, but the value is less in group A which indicates early dissolution of the graft material, in agreement with the study of Lee et al.12. Dense–sparse pattern was more in group A at 1 month (13.3%) and 2 months (60%) compared with group B, in which it was 6.7 and 40% at 1 and 2 months, respectively, which indicates early takeup of graft and its early dissolution in group A compared with group B. We observed, in the second month, sparse pattern was maximum in group B (33.3%) compared with group A (13.3%), indicating more favourability for bone formation in group A. This indicates that PRP enhances new bone formation by its early healing potential 15. The same observations, in terms of radiographic changes in the grafts from radio-opacity to radiolucency, with radiolucency indicating new bone formation, have been reported by Silva et al.16. Kanno et al.17 also observed that PRP exerts a favorable effect on human osteoblast-like cells and acts both to enhance bone regeneration and as an activator in wound healing.
At the sixth-month follow-up, the dense pattern was present in a higher percentage of patients in group A (73.3%) compared with group B (46.7%) in contrast to the sparse pattern, which was more in group B (33.3%) compared with group A (6.7%), which shows that bone maturation was faster in the patients in group A in comparison with the patients in group B. This is almost in agreement with the study of Marx et al. 3 on mandibular continuity defects that were grafted with autogenous bone with PRP and autogenous bone without PRP. A maturity index of about 1.62 was obtained in his study, with a P value 0.001. The increased trabeculation with PRP is in agreement with the observation of Weibrich et al. 18 in their in-vitro studies 19.
In our study, the dense pattern was more in group A at 6 and 12 months than in group B. The proportionate difference in the dense trabecular pattern between group A and group B at 6 months (73.3–46.7%=26.6%) is higher compared with 12 months (86.7–80%=6.7%); this indicates that PRP plays an early role in bone formation and induces earlier maturation of the graft 3.
The clinical and radiographic interpretations in our study conclude that the defectsthat were filled with a PRP+TCP graft combination healed faster compared with the defects filled with a TCP graft alone.
The following conclusions can be drawn from our study on the use of PRP in cystic bony defects of the maxillofacial region.
PRP is autologous and does not induce any significant immunological response and does not pose a risk of transmissible diseases such as HIV, hepatitis B, hepatitis C, etc. PRP improved the handling characteristics of the graft. PRP promoted early consolidation of the graft. PRP promoted earlier maturation of the graft. PRP improved trabecular bone density. PRP provides earlier availability of growth factors and thereby enhances the osteoconductive properties of the graft.
Therefore, PRP, when combined with a graft, is superior in comparison with the plain graft used in filling bony defects of oral and maxillofacial regions.
Conflicts of interest
There are no conflicts of interest.
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