Clinical and Histologic Evaluation of Platelet-Rich Fibrin Accelerated Epithelization of Gingival Wound

INTRODUCTION

The colour of the gingiva plays an important role in overall aesthetics. Ginwalla et al.[1] described the broad black zone of pigmentation on the gingiva as ‘unsightly’ and suggested its removal. The surgical depigmentation procedure essentially involves the removal of gingival epithelium along with a layer of the underlying connective tissue and allowing the denuded connective tissue to heal by secondary intention.

Coverage of exposed connective tissue minimises the likelihood of post-operative haemorrhage and facilitates healing by preventing surface trauma. Conventional non-eugenol periodontal dressings provide an inert mechanical barrier, thereby assisting healing by prevention of external influences on the wound area.[2]

Platelet-rich fibrin (PRF) is a second-generation platelet concentrate and was first developed in France by Choukroun et al., in 2001.[3] It accelerates wound healing by effective neovascularisation and promoting fast cicatricial tissue remodelling and can be used to shield open wounds.[45] PRF membrane as a palatal bandage has been described as an efficacious approach to protect the raw wound area of the palatal donor site.[6] This technique has finally lead to the use of a fibrin and platelet concentrate for the topical and cutaneous application.[78] Therefore, a study was conducted to evaluate clinically and histologically wound healing with PRF membrane as periodontal dressing after depigmentation.

CLINICAL PROCEDURE

Five patients, within an age range of 15–35 years were selected for the study from the Department of Periodontology, who had aesthetic concerns regarding gingival hyperpigmentation [Figures 1a, 2a, 3a, 4a and 5a]. After taking the ethical clearance and patients consent, an infiltration anaesthesia with 2% lignocaine with adrenaline 1:200,000 was administered. The entire visible pigmentation was removed, exposing the underlying connective tissue [Figures 1b, 2b, 3b, 4b and 5b]. A split-mouth design was adopted and in all the patients the gingiva of 1^st quadrant was covered with PRF membrane and sutured with 5-0 silk suture and that of 2^nd quadrant was covered with a periodontal dressing (Coe-Pack) [Figures 1c, 2c, 3c, 4c and 5c]. The PRF was prepared according to the recommended protocol by Choukroun.[3]

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Figure 1

(a) Dummett moderate gingival pigmentation at presentation in maxillary arch, (b) partial thickness flap on the facial surface of the gingiva of the maxillary arch, (c) the right half of the area (1^st quadrant) was covered with platelet rich fibrin membrane and sutured with 5-0 suture and the left half (2^nd quadrant) was covered with non-eugenol periodontal dressing (Coe-Pack), (d) toluidine blue test on 3^rd day, (e) toluidine blue test on 5^th day

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Figure 2

(a) Dummett moderate gingival pigmentation at presentation in maxillary arch, (b) partial thickness flap on the facial surface of the gingiva of the maxillary arch, (c) the right half of the area (1^st quadrant) was covered with platelet rich fibrin membrane and sutured with 5-0 suture and the left half (2^nd quadrant) was covered with non-eugenol periodontal dressing (Coe-Pack), (d) toluidine blue test on 3^rd day, (e) toluidine blue test on 5^th day

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Figure 3

(a) Dummett moderate gingival pigmentation at presentation in maxillary arch, (b) partial thickness flap on the facial surface of the gingiva of the maxillary arch, (c) the right half of the area (1^st quadrant) was covered with platelet rich fibrin membrane and sutured with 5-0 suture and the left half (2^nd quadrant) was covered with non-eugenol periodontal dressing (Coe-Pack), (d) toluidine blue test on 3^rd day, (e) toluidine blue test on 5^th day

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Figure 4

(a) Dummett moderate gingival pigmentation at presentation in maxillary arch, (b) partial thickness flap on the facial surface of the gingiva of the maxillary arch, (c) the right half of the area (1^st quadrant) was covered with platelet rich fibrin membrane and sutured with 5-0 suture and the left half (2^nd quadrant) was covered with non-eugenol periodontal dressing (Coe-Pack), (d) toluidine blue test on 3^rd day, (e) toluidine blue test on 5^th day

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Figure 5

(a) Dummett moderate gingival pigmentation at presentation in mandibular arch, (b) partial thickness flap on the facial surface of the gingiva of the mandibular gingiva, (c) the right half of the area (4^th quadrant) was covered with platelet rich fibrin membrane and sutured with 5-0 suture and the left half (3^rd quadrant) was covered with non-eugenol periodontal dressing (Coe-Pack), (d) toluidine blue test on 3^rd day, (e) toluidine blue test on 5^th day

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Sutures were removed on the 3^rd post-operative day. Wound healing was evaluated on the basis of healing index given by Landry et al.,[9] visual analogue scale scores,[10] epithelization test with toluidine blue and histological evaluation by punch biopsy on 5^th post-operative day at mid of 11 and 21 region in both the quadrants.

RESULTS

Healing index (HI)

At both 3 and 5 days post-operatively [Graph 1], Coe-Pack sites had greater erythematous area as compared to PRF. At 7 days post-operatively, both the sites exhibited normal tissue architecture [Figure 6].

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Graph 1

Graph showing higher values of HI in platelet rich fibrin group as compared to Coe-Pack group

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Figure 6

(a) Histologic evaluation of platelet rich fibrin treated sites with negligible inflammatory cell infiltrate in the connective tissue, (b) histologic evaluation of Coe-Pack treated sites showing chronic inflammatory cell infiltrate in the connective tissue

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DISCUSSION

The scalpel surgery may cause unpleasant bleeding during and after the surgery, and it is necessary to cover the exposed lamina propria as healing occurs with secondary intention, which is delayed.[1112] The use of post-surgical dressings have no curative properties but protect the wound from mechanical trauma and provides patient comfort during tissue healing after surgery.[13] Coe-Pack is a dimensionally unstable material which shows contraction during the first minutes after completion of their setting, resulting in delayed healing.[14] However, PRF is the activated form of a plasmatic molecule called fibrinogen.[15] It is transformed into a kind of biologic glue capable of consolidating the initial platelet cluster, thus constituting a protective wall along vascular breaches during coagulation. It favours the sealing of wound borders and the facilitation of cutaneous reapplication in general and plastic surgery.[161718]

Coe-Pack although is biocompatible yet there are chances of foreign body reaction if the material becomes embedded in the tissues or underneath the flap.[8] PRF has the characteristic of polymerising naturally and slowly during centrifugation and the thrombin concentrations acting on the collected autologous fibrinogen are almost physiologic because there is no bovine thrombin addition.[4]

CONCLUSION

With these fundamental considerations, PRF can be considered as a natural fibrin-based biomaterial favourable to the development of a microvasculariation and able to guide epithelial cell migration to its surface. The interest of such a membrane is evident, namely, to protect open wounds and accelerate healing. Thus, its utilisation seems to be of high interest in dermatologic and plastic surgical procedures.