| Abstract|| |
Background: The palatal donor site of the free gingival graft (FGG) significantly influences the pain and discomfort experienced by the patient, and there is a potential for postoperative bleeding. The aim of this study was to compare the wound healing parameters with the use of a commercially available collagen dressing (CollaCote®) and platelet-rich fibrin (PRF) membrane as palatal bandage. Materials and Methods: Twenty patients requiring FGG either for reduced/inadequate gingiva or gingival recession in the maxillary or mandibular anterior region were divided into two groups. In the first experimental group (10 patients), CollaCote® membrane was placed over the palatal wounds; conversely, the second experimental group patients were treated with a PRF membrane as palatal bandage. Clinical parameters recorded includes depth, immediate, and delayed bleeding, size of wound, pain, and tests for epithelialization which included hydrogen peroxide test and toluidine blue test at various time intervals. Results: Intragroup comparisons showed significant improvement in wound healing parameters in both the groups. No statistically significant difference was found on intergroup comparison with respect to depth, hemorrhage, pain, epithelialization, and size, though the PRF group healed slightly better initially. Conclusion: Both CollaCote® and PRF palatal bandages significantly accelerate palatal wound healing and reduce the patient's pain and discomfort. PRF was easier to handle and suture and is also autogenous and economical as compared to CollaCote®.
Keywords: Collagen, palatal bandage, platelet-rich fibrin, wound healing
|How to cite this article:|
Sharma V, Kumar A, Puri K, Bansal M, Khatri M. Application of platelet-rich fibrin membrane and collagen dressing as palatal bandage for wound healing: A randomized clinical control trial. Indian J Dent Res 2019;30:881-8
|How to cite this URL:|
Sharma V, Kumar A, Puri K, Bansal M, Khatri M. Application of platelet-rich fibrin membrane and collagen dressing as palatal bandage for wound healing: A randomized clinical control trial. Indian J Dent Res [serial online] 2019 [cited 2020 May 24];30:881-8. Available from: http://www.ijdr.in/text.asp?2019/30/6/881/275868
| Introduction|| |
Free gingival graft (FGG) is a surgical technique used to increase keratinized tissue dimensions. The most common site to procure wide, shallow grafts is from the palatal mucosa between distal aspect of the root of canine to mesial aspect of the palatal root of the first molar., The main drawbacks of FGG are the two surgical sites, pain and discomfort experienced by the patient, especially at the donor sites and potential for postoperative bleeding from the donor area which heals by secondary intention resulting in longer healing time and discomfort in the first 2 postoperative weeks.,
To overcome these postoperative problems on the donor site, a variety of methods such as sutures  and dressing materials  have been used, but these provide an inert mechanical barrier, thereby assisting healing by just prevention of external influences on the wound area. These neither influence cellular behavior nor play a major role in the biological events that take place during wound healing.
Collagen dressings have extensively been used in dentistry due to its ability to achieve hemostasis, being chemotactic to fibroblasts and platelets, and inducing mesenchymal proliferation and differentiation. CollaCote ® is a highly porous absorbable type I Bovine Collagen wound dressing fabricated from bovine deep flexor (Achilles) tendon, marketed by Zimmer dental ®. CollaCote ® dressings control bleeding and stabilize blood clots as well as protect the wound bed while accelerating the healing process.
Platelet-rich fibrin (PRF), on the other hand, is a platelet concentrate that contains all the constituents of a blood sample which are favorable for healing and immunity. The slow polymerization mode confers to the PRF a particularly favorable physiologic architecture to support the healing process.,, The fibrin matrix is remodeled in a way comparable with a natural clot and does not dissolve rapidly after application.
The purpose of this study was to compare the efficacy of a commercially available collagen dressing (CollaCote ®) with the autologous PRF membrane as a palatal bandage on the wound healing of palatal donor site of FGG.
| Materials and Methods|| |
Twenty systemically healthy patients (5 males and 15 females) who reported to the outpatient department of periodontology from May 2014 to June 2015 were screened on the basis of inclusion and exclusion criteria, after taking ethical clearance from the Ethical Committee of Institute of Dental Studies and Technologies, with reference number IDST/ERBC/2013/08 and was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2000. This randomized parallel designed human clinical trial is registered at WHO-Clinical Trials Registry-India (CTRI/2017/01/007719).
Systemically healthy patients not under any medication for the past six months, requiring FGG either for reduced/inadequate gingiva or gingival recession in the maxillary or mandibular anterior region and who had not undergone any palatal graft procedure in the past one year, were included in the study. Smokers, pregnant females, lactating mothers, and patients not maintaining oral hygiene were excluded from this study.
Informed written consent was obtained from all the selected participants, fulfilling the inclusion and exclusion criteria. Full mouth plaque index  and gingival index (GI) were recorded. All the selected participants underwent full-mouth scaling and polishing and root planing of the required area and were instructed regarding oral hygiene measures for home care.
The participants were re-evaluated after two weeks, and those having plaque and GI scores of less than one were finally included in the study and underwent routine blood investigations.
Twenty selected participants were randomly allocated to one of the experimental groups, Group 1: Donor site coverage with a commercially available collagen dressing (CollaCote ®) (n = 10); Group 2: Donor site coverage with an autologous PRF membrane (n = 10). Assignment and randomization was done by toss of a coin. To conceal allocation, sequentially numbered opaque-sealed envelopes were used, containing the slips with Group 1 or Group 2 written, were opened during surgery immediately before fabricating the palatal bandage.
A tracing grid stent was fabricated using a transparent sheet keeping it on the maxillary cast between the distal surface of canine and mesial surface of first molar. To standardize the measurements, only two sizes of stents were selected, square stent measuring 15 mm × 15 mm and rectangle stent measuring 18 mm × 12.5 mm both having an area of 225 mm 2. Each stent was divided into five equal parts and six replicas of the stent (square or rectangle) were made. In one of the prepared stents, holes were punched in each of the five parts to measure the depth of donor site (D-stent). The remaining five stents, were prepared with one missing part (either 1, 2, 3, 4, or 5) to apply hydrogen peroxide and toluidine blue solutions exclusively on the area to be examined during the recall visits of the healing phase as shown in [Figure 1]a.
|Figure 1: (a) Tracing grid stent prepared from transparent plastic sheet; (b and c) CollaCote membrane and platelet-rich fibrin membrane sutured at the donor site of free gingival graft, respectively; (d and e) healing of CollaCote group and platelet-rich fibrin group, respectively, at 18th day postoperatively; (f and g) healing of CollaCote group and platelet-rich fibrin group, respectively, at 30th day postoperatively; (h) measurement of depth using “D” stent; (i) evaluation of healing using hydrogen peroxide solution; (j) evaluation of healing using toluidine blue solution; (k) measurement of size|
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All the surgical procedures were performed by one experienced surgeon in all the patients to minimize differences related to surgical technique and patient handling.
Preparation of recipient site
Following the administration of local anesthesia, a #15 blade was used to make a horizontal incision in the vestibule and the recipient bed was undermined. The de-epithelialization of the recipient bed below cementoenamel junction was done in cases where root coverage was anticipated and below recession defect where only increasing the width of attached gingiva was considered. A sterilized aluminum foil template of the recipient site was used to measure the size of graft required at the recipient site.
The prepared stent was placed on the palatal donor site, and the standardized rectangular or square partial thickness graft chosen as per the requirement was harvested from distal aspect of canine till first molar tooth. The blade was inserted to the desired thickness at one edge and lifted using a tissue forceps. The graft was separated using a blade till it was free from all sides. Tissue tags were removed and trimmed to required size. Following the removal of the graft, pressure was applied to the wound area for control of bleeding. Graft measurements were performed by a different examiner.
Suturing of graft at recipient site
The harvested graft was resized and shaped according to the requirement and was sutured on to the recipient site.
Using the prepared aluminum foil template in Group 1 (n = 10 patients), the palatal wound was protected by a commercially available collagen membrane CollaCote ® [Figure 1]b, conversely Group 2 patients (n = 10) had their wound protected using PRF membrane [Figure 1]c prepared according to the protocol recommended by Choukroun et al., The dressings were sutured using four interrupted sutures at four corners of wound by 4-0 silk suture and a 3/8, 16 mm reverse cutting needle.
Wound healing and patient morbidity
The primary outcome was to assess the depth, size of wound, and tests for epithelialization which included hydrogen peroxide test and toluidine blue test, using the prepared standardized stents as described earlier. The secondary outcomes were to assess any immediate or delayed bleeding, and pain/discomfort postoperatively [Figure 1]d, [Figure 1]e, [Figure 1]f, [Figure 1]g.
Following administration of local anesthesia thickness/depth of the palatal mucosa was measured in the holes prepared in the five parts of tracing grid (D-stent) using a sterile standard endodontic K-file of size 15 from the surface of the mucosa to the bone. The depth of the palatal mucosa was measured in both the groups at the center of each column and average depth of five columns was calculated and used as average depth of the wound [Figure 1]h, before surgery, and of the wound immediately after harvesting the graft; postapplication of palatal dressing (CollaCote ® or PRF membrane) and then on 12th, 24th, and 30th postoperative days.
- Immediate bleeding was looked for, after suturing the donor area and 2 min of external pressure. Hemostasis was confirmed when no bleeding was seen, and clinical photograph of the wound was taken without need for suction 
- Delayed bleeding was recorded as prolonged hemorrhaging from the palate during the postsurgical period as reported by the patient at 7th postoperative day.
Pain was recorded according to visual analog pain rating scale on the day of surgery and at 7th, 12th, 18th, 24th, and 30th postoperative days. The scoring was done from 0 to 5.
Epithelialization test by H2O2
Epithelialization test by H2O2 requires recordings on two consecutive days. Hence, healing by H2O2 was also assessed on the 7th, 8th, 12th, 13th, 18th, 19th, 24th, 25th, 30th, and 31st postoperative days. The peroxide test measured the quality of epithelial barrier.,, The area to be evaluated was dried and 3% H2O2 was applied on each of the five cut portions of the prepared tracing grids one by one, thus evaluating healing in a particular region at a time. The negative peroxide test for two consecutive days indicated complete healing [Figure 1]i.
Toluidine blue test
Toluidine blue dye adheres to nonepithelial tissues and imparts blue color to them. Therefore, if dye is not retained it suggests that clinically, the wound is healed.
On the follow-up days, each of the five cut stents/tracing grids were placed on the wound and wound was painted with toluidine blue one by one, thus evaluating the healing in a particular region at a time [Figure 1]j.
Size of the wound was measured using periodontal probe on 7th, 12th, 18th, 24th, and 30th postoperative days. Length and width of the wound were measured and the area was calculated. The raw wound was stained dark by toluidine blue which made the measuring of wound easy [Figure 1]k.
For intragroup analysis, repeated measures ANOVA test was applied as a preliminary test for depth and size and “paired t-test” was then run as a confirmatory test. “Unpaired t-test” was used to compare intergroup results for depth and size. For pain evaluation, epithelialization by toluidine blue and hydrogen peroxide test comparison on follow-up days with baseline was evaluated using Wilcoxon signed-rank test for intragroup comparison, and Mann-Whitney rank sum test was applied for intergroup analysis. Fisher's exact test were used for comparison of nominal/categorical data. The P < 0.05 was taken as significant. Medcalc statistical software version 220.127.116.11 was used for all statistical calculation.
| Results|| |
The number of males were 5 (3 in CollaCote ® group and 2 in PRF group) in the age range of 20–52 years with the mean age 36.2 years and 15 females (7 in CollaCote ® group and 8 in PRF group) in the age range of 18–48 years with the mean age 30.33 years. No patients dropped out of the study, and no postoperative complications were reported by the patients at the end of the study.
The comparisons of all the clinical parameters were done both within and between the two groups and also each of the wound was divided according to the wound configuration into either square (n = 10; 5 CollaCote ® and 5 PRF) or rectangle wound (n = 10; 5 CollaCote ® and 5 PRF).
On intragroup comparison, it was found that when preharvest depth was compared with postdressing depth on the day of surgery and at 12th, 24th, and 30th postoperative days, the difference was statistically nonsignificant for both the groups. When the depth was compared postharvesting and after suturing of dressings in both CollaCote ® and PRF groups, the difference was statistically significant and the difference remained significant at all the follow-up visits. Intergroup comparison difference was found to be nonsignificant [Table 1]. The results were also nonsignificant with square and rectangular wounds.
No case of immediate bleeding in any of the groups was observed. Both the groups showed equal number of delayed bleeding cases (30% of cases). Furthermore, equal number of square and rectangular groups showed delayed bleeding (1 square and 2 rectangular wounds in CollaCote ® group and 2 square and 1 rectangular in PRF group).
No statistically significant difference was observed when pain in both the groups was compared postsurgically on all days, except on the day of surgery, the pain scores and discomfort was seen to be more in CollaCote ® group as compared to PRF which equalizes by the 30th postoperative day [Table 2]. On intragroup comparison statistically significant difference was obtained while comparing the change between the follow-up days, 0–24th day and 0–30th day for CollaCote ® group and on 0–18th day and 0–30th day which shows the early reduction in pain in PRF group, though the intergroup comparisons were nonsignificant.
|Table 2: Intra- and intergroup evaluation of mean pain scores in CollaCote® and platelet-rich fibrin groups at all follow-up days|
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On intragroup comparison of unhealed columns by hydrogen peroxide test and toluidine blue test for both CollaCote ® and PRF groups, statistically significant difference was observed by 18th postoperative day. The test could not be run from the 7th–12th day due high number of similar values (NA). The 7th postoperative day was considered as baseline for test of epithelialization. On intergroup comparison, no statistically significant difference was obtained [Table 3]. No significant difference was observed in rectangular or square wound in both inter- and intragroup comparisons.
|Table 3: Intra- and intergroup comparison of epithelialization by hydrogen peroxide test and toluidine blue test based on unhealed columns|
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On comparing the length, breadth, and area, no statistically significant difference was observed in the healing of both the groups in the same followup days. Faster healing was observed in PRF group initially until the 12th postoperative day; however, this could not reach up to the statistically significant level. Rectangular wounds healed faster though the values were not statistically significant [Table 4]. On intragroup comparison for CollaCote ® group, it was found that 73% of wound area was reduced by 18th postoperative day and 92% by 24th postoperative day. In PRF group, it was found that 81% of wound area was reduced by 18th postoperative day and 92.4% by 24th postoperative day. It was also evident that 90% of wounds healed completely by 30th postoperative day in both groups.
|Table 4: Comparison of wound size at all follow-up days from baseline (day 0)|
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| Discussion|| |
In the present study, the standardization of wound size and shape has been done to study the healing in square wounds and rectangular wounds with wound area of 225 mm 2. This standardization of area helps in comparison of area reduction over time.
FGG may be contraindicated if there is inadequate thickness of palatal mucosa. Sufficient thickness of palatal mucosa is necessary for harvesting FGG from the palate. In our study, the CollaCote ® and PRF were not only used as palatal dressings but also as fillers for maintaining the thickness of palatal mucosa. A similar outcome was reported by Femminella et al. who suggested that the use of PRF have added to the thickness of residual layer of connective tissue.
In the present study, the intragroup comparisons of depth between postharvesting and after suturing of dressings in both CollaCote ®, and PRF groups was statistically significant at all the follow-up visits. This shows that CollaCote ® and PRF both showed equivalent fills and that both these materials can be used as fillers. CollaCote ® being a biocompatible, nonantigenic, and physiologically metabolized material which is fully reabsorbed by the host system could be the reason for the material acting as favorable space filler. PRF, which is a physiologically three-dimensional fibrin network and can be converted into a strong, resistant membrane, resorbs very slowly, and converts into a resistant connective tissue, could have helped in PRF being a good filler.
No immediate bleeding was observed in any of the groups in the present study, as it has been observed that the protection of palatal donor site by any means results in reduced number of cases requiring emergency visit; this was in accordance with Rossmann and Rees.
In our study, we found 30% delayed bleeding in each of the groups. Only a minimal amount of postoperative bleeding was reported by the patients in our study, which stopped after pressure pack and no patient landed in emergency, this may be because of the protection of palate by dressings and also collagen and PRF both have known hemostatic properties., Keceli et al. also reported fewer cases of delayed bleeding when medicinal plant extract was used at the palatal donor site.
In FGG, the donor site is an open wound that makes postoperative healing more painful and discomforting for the patients. Hence, we covered our wounds by either CollaCote ® or PRF. On intragroup analysis, it was observed that pain was reduced significantly by 24th day in CollaCote ® and 18th day in PRF group. Shanmugam et al. and Rastogi et al. also found that collagen dressing relieves pain, as it is biologically acceptable to the oral mucosa and an excellent wound graft material which can dampen the acute inflammatory process during healing. Femminella et al., in a similar study, found lesser patient morbidity in terms of number of analgesics consumed and altered feeding habits in PRF group. In our study, we have found lesser pain scores in PRF group as compared to CollaCote ® group, though the results were statistically nonsignificant, which could be attributed to the smaller sample size, similar to the results obtained by Saroff et al. and Kulkarni et al.
In the present study, the significant difference in wound epithelialization was observed by 18th postoperative day in both the groups in intragroup comparisons. Pedlar  reported complete epithelialization by 8 weeks postexcision of full-thickness palatal mucosa. On intergroup comparison of unhealed columns by hydrogen peroxide test between CollaCote ® and PRF groups, no statistically significant difference was obtained. This signifies that there was a negligible difference in healing in both the groups. Aravindaksha et al., Femminella et al., Kulkarni et al., and Shakir et al. attributed PRF as a palatal dressing as PRF membrane provide a stable fibrin mesh, which is more rigid than a blood clot, it also provides a sustained release of growth factors and by altering the metabolism of epithelial cells and fibroblasts intensifies fibroblast proliferation and migration inside the wound. Shanmugam et al. compared Coe-Pak™ and CollaCote® on FGG palatal wound healing and concluded that collagen-based dressing offers significantly greater advantages. No statistically significant difference was obtained in toluidine blue test as well which confirms the results of hydrogen peroxide test.
On intragroup comparisons of size, >91% of wound size reduction was observed in both the groups by 24th postoperative day. Kulkarni et al. achieved almost complete wound closure by 7th postoperative day in PRF group. Femminella et al. reported complete resolution of palatal wound size in 100% of PRF-treated site by 3rd week and complete healing in 95% of patients in gelatin sponge group by 4th week. This could be due to PRF being a combination of cytokines, structural glycoproteins, and glycanic chains that play a synergetic role in healing and stimulating angiogenesis, immunity and epithelialization. Aravindaksha et al. reported complete healing by 3rd postoperative week in the PRF group. Del Pizzo et al. reported complete healing in 16% and 50% of patients at the 2nd and 3rd week, respectively, in FGG donor sites without any dressing. On intergroup analysis comparing the length, breadth, and area of both CollaCote ® and PRF groups, no statistically significant difference was observed in healing of both the groups at all follow-up days attributed to role of PRF in healing and transformation of absorbable collagen into normal tissue and increase in firmness in CollaCote ® group.,
Although results were statistically nonsignificant, faster healing was observed in PRF group initially till 12th postoperative day. This initial surge in healing in PRF group could be attributed to PRF being a bioactive dressing with a high concentrate of leukocytes and release of growth factors during ≤7 days.,
The healing is also influenced by the shape of its wound as the liner wounds heal fastest followed by rectangular and square wounds and the last to heal wounds are circular wounds. Kahnberg and Thilander  also observed that epithelialization progressed from wound boundaries and reduction of wound surface preceded by contraction of the wound margins and by epithelial cell migration, hence the rectangular wounds should heal faster which is evident in our study, though results were not significant. This could be attributed to the smaller difference in the breadth of both the rectangular and square wounds which led to very less observable difference.
| Conclusion|| |
Both CollaCote ® and PRF could be used as palatal bandages, but we found PRF to be easier to handle and suture as compared to CollaCote ®. PRF also has an advantage of being economic, bioactive autologous material with no chance of any adverse reaction by the host.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Dr. Komal Puri
AK-93, Shalimar Bagh, New Delhi - 110 088
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3], [Table 4]