Periodontitis is a disease prevalent worldwide that often results in severe bone loss around teeth. The most desirable goal of therapy is to achieve the regeneration of tissues destroyed by periodontitis including the alveolar bone, cementum, and periodontal ligament. The ultimate goal of periodontal therapy includes the arrest of progressive periodontal disease and the restitution of those parts of the supporting apparatus that have been destroyed by disease 1. Esthetics is another important consideration 2.
Gingival recession, as defined by The American Academy of Periodontology, is the location of the gingival margin apical to the cemento-enamel junction (CEJ). There may be several causes for recession, which include mechanical factors (trauma, tooth brush abrasion), inflammatory factors (poor oral hygiene, periodontal disease, and restorative considerations), anatomical factors (minimal vestibular depth, frenum involvement, thin periodontium, root prominence, and tooth position), and heredity factors. The effects of these factors have been shown to contribute to sensitivity, cervical abrasion, root caries, and compromised esthetics 3.
The use of an acellular dermal matrix (ADM) allograft [Biohorizon Life Cell, USA, The Woodlands (Innovators in Musculoskeletal science)] facilitates root coverage, which can be achieved without the need for a second surgical site to obtain palatal donor tissue. ADM is an allograft of human skin that has been lyophilized or freeze-dried 4. It differs from typical freeze-dried skin in that all cells have been removed, leaving a connective tissue graft covered by a basal lamina. The patented method of freeze-drying leaves the extracellular matrix, including vascular channels, intact.
Standard methods of processing of freeze-drying skin typically destroy the structure of the extracellular matrix. An advantage of having intact vascular channels is the more rapid revascularization of the allograft by host tissue. ADM works best when completely covered by host tissue. This results in a perfect color match because all surface tissue is host tissue.
The ADM underlies the host tissue and is incorporated as a graft that predictably thickens the host tissue, thereby making the host tissue more resistant to future recession 5.
Platelet-rich plasma (PRP) contains growth factors that may enhance early healing, especially mitogenesis and angiogenesis 6–9. Improved early healing has the potential to improve the clinical outcome of a procedure by promoting more rapid soft tissue attachment to the tooth. Studies of PRP with root-coverage procedures, including a coronally positioned flap (CPF) or a connective tissue graft, showed only a minimal effect on the clinical outcome. The effect when using a soft tissue allograft has not been tested 10–13.
This study was carried out to compare and evaluate the clinical outcome of two techniques that had been used together with a CPF in the management of gingival recession, namely, an ADM allograft with PRP.
Patients and methods
Fourteen patients were selected from those who attended the Out-Patient Clinic of Department of Oral Medicine, Periodontology and Diagnosis, Faculty of Dentistry, Ain Shams University. Patients fulfilled the following inclusion criteria:
All patients selected were free from any systemic diseases assessed using a medical questionnaire guided by the Cornell Medical Index, nonsmokers, either men or women, age range from 20 to 40 years. Patients were excluded if any of the following criteria were present: Debilitating systemic or infectious diseases, a known allergy to any of the materials used in the study; CEJ not identifiable; a root surface restoration at the recession site; failure to maintain an oral hygiene level greater than or equal to 80% plaque-free surfaces; pregnancy or lactation; use of tobacco products through smoking or a smokeless tobacco habit; alcohol abuse problems; long-term steroid therapy; a history of a root coverage procedure, graft, or guided tissue regeneration involving the recession site; and failure to provide informed consent. Patients were given oral hygiene instructions and an adult prophylaxis before inclusion in the study; only patients with an optimum plaque index (PI) of less than 15% were chosen after the initial therapy 14.
Patient grouping and treatment protocol
The 14 patients were divided into two groups. Group 1: This group included seven patients treated with a CPF with Alloderm soaked in PRP. Group 2: This group included seven patients treated with a CPF with PRP.
It was carried out for the two groups at the baseline (at day of surgery) and 3 and 6 months postoperatively. Periodontal assessment included gingival recession depth, PI 15, gingival index (GI), probing depth (PD) 16, and clinical attachment level (CAL) 16. PD and CAL were measured using Ash William’s graduated periodontal probe. Four readings were recorded for each tooth: mesiobuccal, midbuccal, distobuccal, and midlingual.
Surgical protocol: platelet-rich plasma preparation
Before surgery, 10 ml venous blood was drawn from patients randomized to the test group. Blood was collected into glass test tubes that contained 10% trisodium citrate solution as an anticoagulant. The blood-containing glass tubes were centrifuged at 5600 rpm for 6 min, which resulted in the separation of three basic components: platelet-poor plasma on top, PRP in the middle, and the red blood cells at the base of the test tube. Two milliliters of the top layer corresponding to platelet-poor plasma was aspirated using a Pasteur pipette and discarded. PRP was collected in conjunction with the top 1–2 mm of the red blood cells layer as the latter is also rich in newly synthesized platelets. The activation of PRP required mixing the PRP with 4 ml of 40% calcium chloride (thrombin from bovine plasma; Sigma-Aldrich Co., USA) and 5000 U of topical bovine thrombin (Cal Chloride; Alamia Company for Chemicals, Cairo, Egypt) to form a gel.
Alloderm was prepared according to the manufacturer’s instructions. The package was opened and the material was rehydrated in two separate dishes for a minimum of 5 min, the first dish containing 50–100 ml sterile saline and other containing the activated PRP solution prepared previously. Alloderm covered the exposed root/s and extended at least 3 mm on the bone. After smoothing the root surface, the prepared Alloderm was placed over the root surface and sutured by a bioabsorbable (Maxon; Kendall Healthcare, Mansfield, Massachusetts, USA) monofilament polyglyconate 5-0 sling fashion suture to secure the graft at the level of the CEJ around the tooth, and crossover suture was also used over Alloderm apically sutured to the periosteum (Fig. 5). Additional application of PRP preceded a tension-free flap closure, completely covering the Alloderm with the preexisting labial gingival tissues.
Flap preparation (coronally positioned flap)
All procedures were performed under local infiltration of 4% articaine hydrochloride combined with 1 : 100 000 epinephrine (Septanest SP; Septodont, France). An intrasulcular incision was performed with a #15C surgical blade on the buccal aspect of the involved tooth/teeth. Two horizontal incisions were made, at the level of the CEJ, without interfering with the gingival margin of the neighboring teeth (Fig. 3). In multiple teeth cases, additional horizontal incisions were made, connecting the CEJ of the teeth with the recession. Two oblique vertical incisions were extended beyond the mucogingival junction and a trapezoidal mucoperiosteal flap was raised up to the mucogingival junction. After this point, a split-thickness flap was extended apically. The interdental papillae were left intact; hence, their sizes and shapes were preserved. A mesiodistal and apical dissection parallel to the vestibular lining mucosa was made to release residual muscle tension and facilitate coronal flap advancement without tension. The papillae adjacent to the teeth were deepithelialized to provide a connective tissue bed for flap adaptation (Fig. 3).
Adapting the graft and suturing the flap
Flaps were then coronally advanced to cover the exposed root and sutured with a long-lasting suture material. A sling suture was placed to secure the flap coronally. The flap was sutured with a double-sling suture at each flap papilla using a synthetic nonabsorbable polybutester monofilament suture.
Interrupted sutures were placed at the center of the papillae to facilitate closed adaptation of the flap and underlying connective tissue (Fig. 6). Oblique interrupted (Novafil; Kendall Healthcare) sutures were placed toward the coronal direction at the vertical incisions to secure the flap in its new position. Sutures were placed toward the coronal direction at the vertical incisions to secure the flap in its new position. Gentle pressure was applied at the surgical site with moistened gauze to achieve hemostasis and a close adaptation of the flap to the underlying surface. No surgical dressing materials were used.
The postoperative protocol included prescriptions for systemic doxycycline hyclate (Doxy 100M. R.; Adwia Co. S.A.E., Cairo, Egypt) 100 mg once a day for 14 days to prevent plaque from colonizing the graft material to enhance optimal healing and diclofenac potassium (Cataflam 50 mg; Novartis Pharma S.A.E., Cairo, Egypt) 50 mg every 4–6 h for 1 week used as an analgesic and anti-inflammatory. Chlorhexidine digluconate (Oraldine; Kahera Pharmaceutical, Cairo, Egypt) 0.12% (CHX) mouth rinse had to be applied twice daily with a cotton tip applicator for 1 month postoperatively for plaque control. The CHX regimen had to be continued until routine oral hygiene procedures could be resumed at approximately 1 month. The patient was seen for weekly postoperative visits to evaluate healing and plaque control; sutures were removed after 1 month.
Data are presented as mean and standard deviation values. The Mann–Whitney U-test was used to compare the two groups. This test is a nonparametric alternative to Student’s t-test. The Wilcoxon signed-rank test was used to study the changes with time within each group. This test is a nonparametric alternative to the paired t-test. The significance level was set at P≤0.05. Statistical analysis was carried out using SPSS 16.0 (SPSS Inc., Chicago, Illinois, USA) (Statistical Package for Scientific Studies) for Windows.
This study was conducted on 14 patients of both sexes with Miller class I or II gingival recessions, age (22–45) years, attending the Out-Patient Clinic of Department of Oral Medicine, Periodontology and Diagnosis, Faculty of Dentistry, Ain Shams University. They were divided into two groups; each group included seven patients.
Comparison between the two groups
There was no statistically significant difference between the two groups during all periods in the periodontal assessment including gingival recession depth, PI, GI, PD, CAL, and width of keratinized gingival (Tables 1 and 2).
Change with time in each group
In the CPF+ADM+PRP group, there was a statistically significant decrease in the mean gingival recession depth after 3 months, but there was a nonstatistically significant decrease in the mean gingival recession depth after 6 months. In the CPF+PRP group, there was a statistically significant decrease in the mean gingival recession depth after 3 and 6 months. In both groups, there was a statistically significant decrease in the mean PD and CAL after 3 and 6 months. In the CPF+ADM+PRP group, there was a nonstatistically significant increase in the mean width of keratinized gingiva after 3 and 6 months. In the CPF+PRP group, there was a statistically significant increase in the mean width of keratinized gingiva after 3 and 6 months. In both groups, there was a nonstatistically significant decrease in the mean PI and GI after 3 and 6 months (Fig. 1).
The ultimate goal of any therapeutic intervention aimed at root coverage should be to restore the tissue margin at the CEJ and to achieve attachment of the tissues for a normal healthy gingival sulcus with no bleeding on probing and a minimal PD 17. Patients have become more aware of dental esthetics and demand precision treatment> of their exposed root surfaces. It is difficult to anticipate the success rate of root coverage procedures, as coverage depends on several factors, including the classification and location of the recession and the technique used.
The use of Alloderm soaked in PRP and PRP alone covered by a CPF in this study to attain root coverage may alleviate the need for donor site procurement of connective tissue. This has led to investigations of a more regenerative nature. The use of barrier membranes is another trend 18. Pini Prato et al. 19 showed that the greater the coronal positioning, the more likely it is that complete defect coverage will be achieved.
PRP can also be infused into resorbable barrier membranes to retard epithelial migration, as well as to provide localized growth factors to accelerate hard and soft tissue maturation 20. The use of an ADM as a substitute for connective tissue when covered by a CPF is a relatively new approach that allows the coverage of multiple sites and does not require autogenous donor tissue 21,22. Currently, controlled studies show stable results for up to 1 year; however, additional studies are needed to confirm the long-term stability of this treatment 23,24. Studies that used Alloderm showed mean defect coverage ranging from 66 to 99%, with a mean of 86% for all studies 22,25. The mean final root exposure ranged from 0.2 to 1.1 mm relative to a mean initial recession of 3.7 mm 22,25.
Lien-Hui Huang et al. 8 found that CPF is a predictable approach to treat Miller’s class I gingival recession. The additional application of PRP failed to improve root coverage after CPF in Miller’s class I recession defects. However, a positive trend of PRP utilization was observed as lower GI and wound healing index values as well as increased GT postoperatively were observed in this group. No statistically significant differences were noted between groups, suggesting that both procedures are comparable for the treatment of Miller’s class I recession defects. The mean root coverage at 6 months was 83.5–21.8% in CAP and 81.0–28.7% in PRP+CAP. Complete root coverage was achieved in 58.3% of CAP-treated sites and 63.6% of PRP+CAP sites. These results were in agreement with those obtained by Pini Prato et al. 23, Modica et al. 26, and Pini Prato et al. 27. Also, these results were similar to our study, in which the mean root coverage at 3 and 6 months was 81.6–83.3%, respectively, in PRP+CAP. This may be partly because of the favorable results obtained in the two groups, the small sample size, and defects (Miller’s class I) known to experience predictable root coverage 8. These results were similar to our study, in which there was no statistically significant difference between the two groups; in this study, we chose defects (Miller’s class I and ΙΙ).
In group 1 (ADM+PRP+CPF), the mean recession reduction was 81.3 and 59.9% before treatment – 3 months and before treatment – 6 months, respectively, root coverage as regards the present study. This limited amount of root coverage may be because of shrinkage of the Alloderm and retraction of the flap. Noveas and Souza 28 treated gingival recession defects with an ADM graft. They followed up the results for 6 months. They achieved a 2.01 mm recession reduction and 66% root coverage. The results were not comparable with those of this study because of the difference in the surgical technique, which included the papilla in the flap. Moreover, the exposed root surface was conditioned with 50 mg/ml tetracycline solution for 3 min. This could explain the wide difference in the results. However, the present results were in agreement with those of Aichelmann Reidy et al. 29, who achieved 1.7 mm recession reduction after the treatment of gingival recession with an acellular allograft.
The width of keratinized gingiva increased because of the proliferation of granulation tissue from the periodontal ligament, which is able to induce keratinization 30. In this study, there was a statistically insignificant increase in the mean width of keratinized gingiva 3 and 6 months after the treatment of recession defects by CPF+ADM+PRP. This may be because of excessive shrinkage of the Alloderm during healing. However, there was a statistically significant increase in the mean width of keratinized gingiva after 3 and 6 months in defects treated with CPF+PRP. These results of this study were in contrast to those of Henderson et al. 25, who reported a slight decrease in PD after 1 year when 10 recession defects were treated with Alloderm. However, the results of present study were different from those of Noveas and Souza 28 and Aichelmann Reidy et al. 29, who found an increase in the PD. The mean change of CAL from baseline to the 24th week was similar in both groups; there was a statistically significant decrease in the mean CAL. The results of this study were in agreement with those reported by Noveas and Souza 28. In the absence of histologic evidence, it is impossible to determine whether this gain in attachment is a result of the formation of a long junctional epithelium, a new connective tissue attachment, or a combination of both types of healing.
The lack of a statistical difference between the groups in this study may have been because of the sample size; there were seven patients in each group. The lack of a large sample size can lead to type 2 errors, or a false negative, which means that there was failure to reject the null hypothesis when it should have been rejected and a difference between the groups was detected. Larger studies are needed to determine whether there is a statistically significant difference between the groups. Irrespective of the statistical significance, there was, in our opinion, a clinically significant difference in defect coverage between the groups (59.9 vs. 83.3%). Because there was a lack of statistical power, it is most appropriate to consider this a pilot study (Figs 2–7).
A CPF in addition to an ADM graft soaked in PRP are useful and predictable surgical techniques; they can produce reliable root coverage after 3 and 6 months, and similar results in relation to root coverage improving esthetics.
A CPF in addition to PRP produced reliable root coverage after 3 and 6 months, and improved esthetics. Patients included in this study were satisfied with the results.
Conflicts of interest
There are no conflicts of interest.
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