|Year : 2013 | Volume
| Issue : 3 | Page : 345-353
Use of autologous platelet rich plasma to treat gingival recession in esthetic periodontal surgery
Archana R Naik1, Alampalli V Ramesh2, CD Dwarkanath3, Madhukeshwara S Naik4, AB Chinnappa5
1 Department of Periodontics, Dayananda Sagar College of Dental Sciences, Bangalore, Karnataka, India
2 Department of Periodontics, Oxford Dental College, Bangalore, Karnataka, India
3 Department of Periodontics, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India
4 Department of Oral and Maxillofacial Surgery, Bangalore Institute of Dental Sciences, Bangalore, Karnataka, India
5 Srusthi Writings, Bangalore, Karnataka, India
|Date of Submission||16-Jan-2012|
|Date of Acceptance||17-May-2013|
|Date of Web Publication||25-Jul-2013|
Archana R Naik
Department of Periodontics, Dayananda Sagar College of Dental Sciences, Kumara Swamy Layout, Bangalore - 560 078, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Multiple approaches have been used to replace lost, damaged or diseased gingival tissues. Coronally advanced flap (CAF) and the use of guided tissue regeneration are among the successfully used surgical techniques to treat gingival recession. Platelet rich plasma (PRP), containing autologous growth factors, has been shown to promote soft-tissue healing. Therefore, the purpose of this study was to evaluate the efficacy of PRP in combination with CAF in the treatment of gingival recession. Materials and Methods: A total of 15 systemically healthy patients with buccal Miller's class I and class II gingival recession in cuspids or premolars participated in the study. CAF procedure was performed and PRP with collagen sponge was placed over the defect. Clinical parameters such as recession depth, recession width, surface area, width of keratinized gingival (KG), clinical attachment level (CAL), probing depth, plaque index and gingival index were evaluated at 3, 6 and 9 months post-surgery. The percentage of root coverage was calculated. Results: The results of this study suggest that the CAF procedure provides a predictable and simple technique in the treatment of localized Class I and Class II gingival recession. The additional application of PRP does significantly increase the width of KG and gain in clinical attachment. Conclusion: CAF procedure is a predictable and simple technique in the treatment of gingival recession and the additional application of PRP does significantly increase the width of KG and gain in CAL. The long-term benefits following surgical treatment of such defects needs to be determined further.
Keywords: Collagen, coronally advanced flap, gingival recession/surgery, growth factors, platelet rich plasma, soft-tissue healing
|How to cite this article:|
Naik AR, Ramesh AV, Dwarkanath C D, Naik MS, Chinnappa A B. Use of autologous platelet rich plasma to treat gingival recession in esthetic periodontal surgery. J Indian Soc Periodontol 2013;17:345-53
|How to cite this URL:|
Naik AR, Ramesh AV, Dwarkanath C D, Naik MS, Chinnappa A B. Use of autologous platelet rich plasma to treat gingival recession in esthetic periodontal surgery. J Indian Soc Periodontol [serial online] 2013 [cited 2020 Jun 1];17:345-53. Available from: http://www.jisponline.com/text.asp?2013/17/3/345/115665
| Introduction|| |
The primary objective of periodontal therapy is to improve the periodontal health and to preserve the dentition. However, esthetics has become an inseparable part of oral therapy recently. With the increasing popularity of cosmetic dentistry, root coverage procedures to enhance the level of keratinized tissue around exposed tooth surfaces have gained popularity over the last few years.
Gingival recession can be localized or generalized and can cause major functional and esthetic problems as it may result in a higher incidence of root caries, periodontal attachment loss and hypersensitivity;  more importantly gingival recession needs to be treated because of esthetic concerns.  Therefore, root coverage procedures have been developed to treat these conditions. Various modalities of root coverage procedures exist. These include laterally sliding flap,  double papilla flap,  subepithelial connective tissue graft,  coronally advanced flap (CAF),  free gingival autograft  and guided tissue regeneration techniques.  The most recent advances in root coverage include the use of various adjunctive agents such as acellular dermal matrix graft,  enamel matrix derivative,  recombinant human growth factor and platelet rich plasma (PRP). PRP derived from concentrated platelets is identified as one mediator, which has many growth factors. These growth factors are important at all stages of cell cycle and may stimulate chemotaxis and production of extracellular matrix proteins.  Administration of these growth factors may be combined with tissue regeneration techniques in repair of intrabony defects,  furcation  and sinus augmentation.  All these procedures have demonstrated new bone formation and bone healing. However, there is limited evidence regarding its effects on soft -tissue healing. There are only few case reports wherein PRP is used to treat gingival recession. , Hence, the present study was taken up by doing a series of cases to assess the outcome of CAF along with PRP in the treatment of gingival recession. The objective of this study was to evaluate the effectiveness of PRP with collagen sponge as an adjunct to CAF procedure and to assess the soft-tissue healing with the use of PRP.
| Materials and Methods|| |
The study was approved by the ethical committee of Oxford Dental College. Patients who visited the out-patient department of Periodontics, Oxford Dental College, Bangalore, India, for either dentin hypersensitivity or esthetic concerns were evaluated to be included in the study. The clinical trial included 15 male patients ranging in age from 21 years to 38 years (mean age 27 years).
Patient selection criteria for this clinical study included the following:
Exclusion criteria were
- Age of 18 years or more
- Miller's class I or II buccal recession defect with recession depth (RD) of ≥2 mm
- Radiographic evidence of sufficient interdental bone
- Probing sulcus depth (PD) of ≤3 mm
- A minimum width of keratinized gingiva (KG) of 1 mm.
Each participant completed initial therapy consisting of oral hygiene instructions, scaling, root planing of the required teeth, polishing and occlusal adjustment if necessary. After 4 weeks, patient's oral hygiene was evaluated. Study models of the teeth were prepared.
- Medically compromised patients
- Those on corticosteroids and other immune modulators
- Tooth with the endo-perio problem
- Aggressive periodontitis.
Data were collected on the standard case history proforma. All clinical measures were made to the nearest 0.5 mm with a standard University Of North Carolina (UNC-15) manual probe. For the tooth selected for surgery, the following measurements were recorded: RD, recession width (RW), surface area (SA) of the defect, width of KG, clinical attachment level (CAL) and PD.
RD was measured from the midfacial point of the cemento-enamel junction (CEJ) to the free gingival margin (FGM). The recession width (RW) was recorded at a level of 1 mm apical to the CEJ. The width of KG was determined by subtracting the RD measure from the CEJ- mucogingival junction (MGJ) distance. The SA of the defect was measured by placing tin foil over the defect, conform it to the shape of the defect, placing this foil over a graph paper and then counting the number of squares in the area of the foil. The SA was calculated in square millimetres. Two half squares were considered as one square. All parameters were again measured at 3, 6 and 9 months. Wound healing index (WHI)  was recorded 1 week after surgery using the following criteria: Score 1 = uneventful healing with no gingival edema, erythema, suppuration, patient discomfort or flap dehiscence; Score 2 = uneventful healing with slight gingival edema, erythema, patient discomfort or flap dehiscence, but no suppuration; and Score 3 = poor wound healing with significant gingival edema, erythema, patient discomfort, flap dehiscence or any suppuration. Additional clinical data were obtained by taking pre-operative photographs and at each post-operative visit.
The percentage of root coverage (PRC) was calculated according to the following formula: 
To measure oral hygiene, plaque index was recorded according to the criteria for the PI (Silness and Loe 1964).  Recordings for gingival status was made according to the criteria for GI by Loe and Silness. 
Preparation of PRP
One hour before the surgery, 8 ml of blood was drawn from the antecubital vein into the vacutainers (Vacuette R ) containing 3.2% anticoagulant sodium citrate. To separate and concentrate platelets, two separate centrifugations (referred to as spin) were done. In the first spin, the blood was centrifuged at 2000 rpm for 2 min. This separates the red blood cells from the rest of the whole blood (white blood cells, Platelets and Plasma) with a thin white line in between (called as buffy coat), which has maximum concentration of platelets. The plasma and the buffy coat were pipetted out in a separate test tube and centrifuged (second spin) at 4000 rpm for 8 min. The second spin results in two separate fragments. The bottom layer is the PRP which is overlaid by supernatant fluid platelet poor plasma (PPP). PPP is pipetted out in a separate test tube. The PRP is then used for the procedure.  For the purpose of this study, PRP was obtained by the modified method of Curasan. 
The surgical procedure was performed under local infiltration with 2% lignocaine containing adrenaline at a concentration of 1:200,000. After obtaining adequate anesthesia, two vertically divergent incisions (i.e., one mesial and one distal, immediately adjacent to the defect) extending beyond the MGJ was made on the buccal aspect of the involved tooth. Sulcular incision was then placed up to the end of vertical incisions [Figure 1] and [Figure 2]. Care was taken to see that the papilla was intact. A trapezoidal mucoperiosteal flap was elevated by blunt dissection to the level of the MGJ. In the area apical to the MGJ, partial thickness dissection was employed [Figure 3]. The vertical incision was extended apically, well beyond the MGJ and into the mucobuccal fold, to a point where the flap could be positioned over the original defect without tension. In the adjoining interdental papilla, de-epithelialization was carried out with a B.P blade no. 11 to provide a bleeding connective tissue bed for the future CAF.
The exposed root surface was thoroughly planed and contoured by no. 3-4 Gracey curette as a part of mechanical root biomodification. A measurement of the appropriate width necessary for the graft was obtained with a periodontal probe. Here, collagen sponge (Collacote R Integra LifeSciences Corporation.) was used as a carrier for PRP. The collagen sponge was properly trimmed according to the measured defect size. The PRP was poured over the membrane until it was fully soaked. Then two drops of 10% calcium chloride and autologous blood was used for activation of PRP to initiate coagulation and formation of PRP gel. The platelet concentrate graft was placed over the denuded root extending from 2 mm apical to the crest of the alveolar bone up to the CEJ below and to the incision lines at the sides [Figure 4]. The flap was then coronally positioned to completely cover the graft and secured by sling suture using no. 4-0 bioabsorbable suture (VICRYL TM , Johnson and Johnson). The vertical incisions were then sutured with two direct interrupted sutures on either side [Figure 5]. A tin foil of suitable size was placed on the buccal aspect and a non-eugenol periodontal dressing (Coe-Pak, GC) was adapted [Figure 6]. Post-operative instructions were given and patient was recalled for follow-up regimen (1 week, 3, 6 and 9 months). Similar surgical protocol was adopted for all patients.
|Figure 4: Case 1: Platelet rich plasma with collagen sponge placed over the defect|
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Analgesics (non-steroidal anti-inflammatory drug Ibuprofen 200 mg) were prescribed to control post-operative discomfort. No antibiotics were prescribed. Patients were asked to refrain from oral hygiene measures on the treated areas for 10-12 days and instructed to rinse the mouth with warm salt water twice daily for 2 weeks. From the third week of surgery, patients were instructed to resume mechanical tooth cleaning using a soft brush with a careful roll technique.
Patients were recalled after one week for post-operative check up to evaluate the healing [Figure 7]. Periodontal pack was removed followed by irrigation with saline.
The follow-up was carried out at three, six and nine months. All clinical measurements were recorded during the follow-up visit.
- Quantitative data were summarized as mean ± standard deviation. Repeated Measures Analysis of variance (ANOVA) has been used to find the significance of study parameters between baseline, at 3 months, at 6 months and at 9 months
- Student t-test with Bonferroni correction has been used to investigate the significance of the difference between two population means. No assumption is made about the population variances. 
The Statistical software namely SPSS 15.0, Stata 8.0, MedCalc 9.0.1 and Systat 11.0 were used for the analysis of the data and Microsoft Word and Excel have been used to generate graphs and tables.
| Results|| |
Fifteen patients aged between 21 years and 38 years (mean age 27 years) were enrolled in the study of which thirteen patients completed all the follow-up protocol and were considered for the study. A total of 15 gingival recessions comprising of 9 canines and 6 premolars were treated with CAF and PRP.
Healing was uneventful in all patients with very minimal pain post-operatively. The mean WHI was assessed by examining for erythema and edema, was 1.33 ± 0.59, which was more towards normal and favorable with uneventful healing. However, in one case, flap perforation occurred inadvertently, which was managed by coronally advancing the flap and suturing it has done in the rest of the cases.
PRP was prepared one hour prior to surgery by the modified Curasan method  as per the technique described in the methodology. PRP samples of two cases were randomly selected for platelet count using cell counter. The count was in the range of 4.8 lakhs to 7 lakhs/μl.
Plaque index and gingival index
The post-surgery defect specific plaque index and gingival index did not increase beyond 0.5 at any time during the post-operative period. There was no statistically significant difference between the plaque index and gingival index at baseline and that observed post operatively (P = 0.584 and P = 0.274, respectively) [Table 1] and [Table 2].
There was a gradual decline of probing depth from baseline to 3 and 6 months and at the end of 9 months it was moderately significant with a P value of 0.019. The mean probing depth at 3 months was 1.57 mm (reduced by 0.13 mm compared to baseline) while it was 1.07 mm at 6 months (reduced by 0.63 mm) and 0.81 mm at the end of 9 months (reduced by 0.89 mm) [Table 3], [Graph 1].
|Table 3: Summary of change from baseline to 3, 6 and 9 month interval with p value of the following clinical parameters|
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Clinical attachment level
The mean baseline CAL was 3.97 mm. At 3 months, the mean CAL was 2.63 mm reflecting an attachment gain of 1.34 mm. The mean CAL at 6 and 9 months were 2.10 mm and 1.43 mm reflecting an attachment gain of 1.87 mm respectively. At 6 months, the mean CAL was 2.10 mm showing an attachment gain of 1.87 mm. At 9 months, the mean CAL was 1.43 mm again showing an attachment gain of 2.54 mm. The change was highly significant with P < 0.001 [Table 3], [Graph 2].
The mean RW was 2.63 mm at baseline, which decreased to 1.47 mm at 3 months, 1.57 mm at 6 months and to 0.94 mm at 9 months. The decrease in RW was highly significant (P < 0.001) with the percentage of decrease in RW being 61.3% at the end of 9 months [Table 3], [Graph 3].
The mean recession depth was 2.33 mm at baseline, which decreased to 0.87 mm at 3 months and 0.80 mm at 6 months. The recession depth significantly reduced to 0.5 mm at 9 months. The decrease in recession depth was highly significant (P < 0.001) with an improvement of 78.5% at 9 month [Table 3], [Graph 4].
SA of the defect
The mean baseline SA was 5.27 mm 2 , which decreased to 2.20 mm 2 at 3 months and 2.63 mm 2 at 6 months postoperatively. Further, the mean SA significantly reduced to 1.63 mm 2 at 9 months (69.1% decrease) P < 0.001; [Table 3], [Graph 5].
Width of KG
The mean width of KG at baseline was 2.63 mm. At 3 months, the width increased to a mean of 3.27 mm and 3.43 mm at 6 months. At the end of 9 months, the width increased to 3.50 mm. The change was highly significant with P < 0.001 amounting to an increase in gain of KG by 33.1% [Table 3], [Graph 6].
PRC is the result of decrease in RW, recession depth and SA of the defect. All treated sites gained root coverage. At 3 months, the mean root coverage was 62.55% while it was 65.33% and 78.75% at 6 months and 9 months, respectively [Table 3], [Graph 7].
Among the study group, three of the 15 defects showed complete root coverage [Figure 8], [Figure 9], [Figure 10], [Figure 11] and [Figure 12]. The site with buccal perforation showed the least, with 20% root coverage.
|Figure 9: Case 1: 6 month post-operative view with complete root coverage|
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|Figure 11: Case 2: Pre-operative recession depth of 3 mm in relation to 44|
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|Figure 12: Case 2: 9 month post-operative view with complete root coverage|
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| Discussion|| |
Although root coverage is a desirable outcome, it is necessary to achieve an increased zone of KG, reduced probing depth as well as gain in CAL. PRP, rich in growth factors has been shown to enhance soft-tissue healing, promote initial clot stabilization and revascularization of the flaps and grafts in root coverage procedures. However, limited evidence is currently available verifying these claims. Therefore, this study was conducted to study the effects of PRP on CAF procedure.
In general, PRP, when used along with bone graft, acts as a scaffold and enables to be placed easily in an intrabony defect or a furcation defect. Since placement of PRP on a recession defect is difficult, a collagen sponge (Collacote R Integra LifeSciences Corporation), a wound dressing material, was used as a carrier for PRP. The benefits of this collagen sponge include controlling the bleeding and stabilization of blood clot, protection of the wound bed, provides a matrix for tissue ingrowth and gets fully absorbed in 10-14 days.
The results of the present study demonstrated that use of PRP in CAF procedure may lead to consistent RD reduction and considerable improvement in root coverage.
In the present study, PRP was prepared one hour prior to surgery and when the platelet count was randomly checked, the number of platelets were 4 times greater than the baseline value of 1.5 lakh/μl. This was similar to the value obtained by Marx  who has shown that this concentration was enough to produce clinical benefits. This method is preferred because it requires only 8 ml of blood, less time for preparation and can be used in routine dental set up.
In the present study, during one week post-operative examination, the gingival appearance was evaluated by examining for erythema and edema. In all cases, gingival appearance was nearly normal with appearance varying between "no gingival erythema or edema to a slight erythema and edema" (as evident in [Figure 7]). Patient discomfort was present only on the first day and with very minimal post-operative pain. This shows an accelerated soft-tissue healing. PRP is known to contain higher levels of platelet derived growth factor (PDGF), transforming growth factor β (TGF-β) and vascular endothelial growth factor (VEGF) and these growth factors may reportedly enhance soft-tissue healing by hastening the angiogenesis and matrix biosynthesis during early wound healing.
Plaque and gingival indices remained relatively constant at all-time intervals during the experimental period. Probing depth was included as an assessment parameter to detect if there was a negative effect of therapy in terms of increasing buccal probing depth. There was a reduction in probing depth of 0.63 mm, which was moderately significant from pre-operative to post-operative examination.
There was an average gain in CAL of 1.87 mm at 6 months and 2.54 mm at 9 months. This gain in CAL was accompanied by reduction in probing depth and recession depth. Considering that root coverage was achieved in these situations, the gain in CAL suggests the formation of new attachment to the root surface, although, in the absence of histological evidence, it is not possible to determine the type of gain in attachment. The gain in CAL might be attributed to the growth factors secreted by PRP would have attached to the membrane in the cells in the flaps and to the underlying root surface and prevented shrinkage.
The presence of an "adequate" zone of gingiva has been considered critical for the maintenance of gingival health.  There was a gain of 0.8 mm from baseline to 6 months while Huang et al.  achieved 0.4 mm gain of KG with the use of PRP on CAF. Since the stimulation for keratinization of surface epithelium is provided by underlying connective tissue, it can be construed that the newly formed connective tissue had the ability to induce keratinization. The newly formed connective tissue, helped by PRP, possessed the ability to induce keratinization of overlying epithelium.
However, the mean recession depth reduction was less as compared to Pini Prato study, where a mean recession depth reduction of 4.12 mm was seen for CAF technique alone and 2.3 mm mean recession depth reduction by Huang et al. for CAF procedure along with PRP and whereas, in our study, the mean depth reduction was 1.53 mm. This difference in the mean reduction can be explained based on the selection of the size of the defect sites. In the present study, a baseline value of 2-3 mm of recession depth was selected, whereas in the group selected by Pini Prato, the recession depth ranged from 3-8 mm. As reported by Pini Prato  sites with deeper recession defects tend to respond more favourably than shallower sites.
The 6 month and 9 month data indicates that a CAF operation with PRP is as efficient as the other procedures in terms of root coverage. The mean root coverage at 6 months was 65.33% and 78.75% at 9 months. Studies show mean defect coverage ranging from 50% to 98% with a mean for all studies of 78%. Predictability data indicated that 90% or greater defect coverage was achieved 39% of the time.  The percentage root coverage obtained in the present study is within the range of reported results of 64.2%,  75%,  78%,  97.1%,  97.8%  and 98.8%. 
The difference in the outcomes of treatment in the present study and other studies may be attributed to technical and anatomic factors. Technical factors such as operator experience/surgical skills and the occurrence of a learning curve during the study may also account for the difference between the studies. The measurement techniques employed also differ in some studies. Other anatomical factors such as root prominence, depth of the vestibule, soft-tissue quality - all these variables were not considered and might also have accounted for a less favourable outcome.
When keeping in mind the various limitations, the degree of root coverage obtained in the present study compares well with other reports. The additional benefits obtained with the use of PRP are:
In addition, the use of PRP promotes a more rapid vascularization delivering growth factors specific for capillary formation. Hence in the present study, one week post-operative cases showed less erythema and the tissues appeared normal and comparable with the adjacent area. PRP is known to contain higher levels of PDGF, TGF-β and VEGF. These growth factors might enhance soft-tissue healing by increasing the angiogenesis and matrix biosynthesis during early wound healing.
- It decreased the incidence of both intraoperative and post-operative bleeding at the receptor sites because of its inherent hemostatic properties
- Decreased the incidence of postoperative pain
- Also, the thickness of the KG was increased.
However, this short term benefit did not significantly influence the final clinical outcomes, e.g., PRC. But a significant increase in CAL and width of KG was definitely observed. Nevertheless, histological examination needs to be performed to determine the type of attachment.
| Conclusion|| |
Keeping in mind the ample information available about the properties of PRP and the improvements seen in the various clinical parameters, it can be assumed that PRP along with collagen sponge is beneficial in the treatment of gingival recession. However, a clinical trial with larger sample size supported by histologic study is needed to provide evidence of PRP's impact on wound healing and the clinician's quest for periodontal regeneration.
| Acknowledgments|| |
The authors wish to thank Mr. Srinikanth for helping us to take good photographs and arranging them and Mr. K. P. Suresh, Biostatistician for helping us with graphs and statistics.
| References|| |
|1.||Rees JS, Addy M. A cross-sectional study of dentine hypersensitivity. J Clin Periodontol 2002;29:997-1003. |
|2.||Oliver RC, Brown LJ, Löe H. Periodontal diseases in the United States population. J Periodontol 1998;69:269-78. |
|3.||Grupe H, Warren RJ. Repair of gingival defects by a sliding flap operation. J Periodontal 1956;27:290-5. |
|4.||Cohen DW, Ross SE. The double papillae repositioned flap in periodontal therapy. J Periodontol 1968;39:65-70. |
|5.||Langer B, Langer L. Subepithelial connective tissue graft technique for root coverage. J Periodontol 1985;56:715-20. |
|6.||Bernimoulin JP, Lüscher B, Mühlemann HR. Coronally repositioned periodontal flap. Clinical evaluation after one year. J Clin Periodontol 1975;2:1-13. |
|7.||Brackett RC, Gargiulo AW. Free gingival grafts in humans. J Periodontol 1970;41:581-6. |
|8.||Harris RJ. A comparative study of root coverage obtained with guided tissue regeneration utilizing a bioabsorbable membrane versus the connective tissue with partial-thickness double pedicle graft. J Periodontol 1997;68:779-90. |
|9.||Harris RJ. A short-term and long-term comparison of root coverage with an acellular dermal matrix and a subepithelial graft. J Periodontol 2004;75:734-43. |
|10.||Cueva MA, Boltchi FE, Hallmon WW, Nunn ME, Rivera-Hidalgo F, Rees T. A comparative study of coronally advanced flaps with and without the addition of enamel matrix derivative in the treatment of marginal tissue recession. J Periodontol 2004;75:949-56. |
|11.||Lynch SE. The role of growth factors in periodontal repair and regeneration. In: Polson AM, editor. Periodontal Regeneration: Current Status and Directions. St. Louis: Quintessence Publishing Co, Inc.; 1994. p. 179-98. |
|12.||Camargo PM, Lekovic V, Weinlaender M, Vasilic N, Madzarevic M, Kenney EB. Platelet-rich plasma and bovine porous bone mineral combined with guided tissue regeneration in the treatment of intrabony defects in humans. J Periodontal Res 2002;37:300-6. |
|13.||Lekovic V, Camargo PM, Weinlaender M, Vasilic N, Aleksic Z, Kenney EB. Effectiveness of a combination of platelet-rich plasma, bovine porous bone mineral and guided tissue regeneration in the treatment of mandibular grade II molar furcations in humans. J Clin Periodontol 2003;30:746-51. |
|14.||Froum SJ, Wallace SS, Tarnow DP, Cho SC. Effect of platelet-rich plasma on bone growth and osseointegration in human maxillary sinus grafts: Three bilateral case reports. Int J Periodontics Restorative Dent 2002;22:45-53. |
|15.||Petrungaro PS. Using platelet-rich plasma to accelerate soft tissue maturation in esthetic periodontal surgery. Compend Contin Educ Dent 2001;22:729-32, 734, 736 passim; quiz 746. |
|16.||Griffin TJ, Cheung WS. Treatment of gingival recession with a platelet concentrate graft: A report of two cases. Int J Periodontics Restorative Dent 2004;24:589-95. |
|17.||Huang LH, Neiva RE, Soehren SE, Giannobile WV, Wang HL. The effect of platelet-rich plasma on the coronally advanced flap root coverage procedure: A pilot human trial. J Periodontol 2005;76:1768-77. |
|18.||Shieh AT, Wang HL, O'Neal R, Glickman GN, MacNeil RL. Development and clinical evaluation of a root coverage procedure using a collagen barrier membrane. J Periodontol 1997;68:770-8. |
|19.||Silness J, Loe H. Periodontal disease in pregnancy. II. Correlation between oral hygiene and periodontal condition. Acta Odontol Scand 1964;22:121-35. |
|20.||Löe H. The gingival index, the plaque index and the retention index systems. J Periodontol 1967;38:610-6. |
|21.||Tözüm TF, Demiralp B. Platelet-rich plasma: A promising innovation in dentistry. J Can Dent Assoc 2003;69:664. |
|22.||Weibrich G, Kleis WK. Curasan PRP kit vs. PCCS PRP system. Collection efficiency and platelet counts of two different methods for the preparation of platelet-rich plasma. Clin Oral Implants Res 2002;13:437-43. |
|23.||Rosner B. Fundamentals of Biostatistics. 5 th ed. Duxbury: Pacific Grove, California; 2000. p. 55-105. |
|24.||Marx RE, Carlson ER, Eichstaedt RM, Schimmele SR, Strauss JE, Georgeff KR. Platelet-rich plasma: Growth factor enhancement for bone grafts. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:638-46. |
|25.||Lang NP, Löe H. The relationship between the width of keratinized gingiva and gingival health. J Periodontol 1972;43:623-7. |
|26.||Pini Prato G, Tinti C, Vincenzi G, Magnani C, Cortellini P, Clauser C. Guided tissue regeneration versus mucogingival surgery in the treatment of human buccal gingival recession. J Periodontol 1992;63:919-28. |
|27.||Greenwell H, Fiorellini J, Giannobile W, Offenbacher S, Salkin L, Townsend C, et al. Oral reconstructive and corrective considerations in periodontal therapy. J Periodontol 2005;76:1588-600. |
|28.||Trombelli L, Tatakis DN, Scabbia A, Zimmerman GJ. Comparison of mucogingival changes following treatment with coronally positioned flap and guided tissue regeneration procedures. Int J Periodontics Restorative Dent 1997;17:448-55. |
|29.||Bernimoulin JP, Mulehaman HR. Coronally positioned periodontal flap. J Clin Periodontol 1975;2:1-13. |
|30.||da Silva RC, Joly JC, de Lima AF, Tatakis DN. Root coverage using the coronally positioned flap with or without a subepithelial connective tissue graft. J Periodontol 2004;75:413-9. |
|31.||Wennström JL, Zucchelli G. Increased gingival dimensions. A significant factor for successful outcome of root coverage procedures? A 2-year prospective clinical study. J Clin Periodontol 1996;23:770-7. |
|32.||Allen EP, Miller PD Jr. Coronal positioning of existing gingiva: Short term results in the treatment of shallow marginal tissue recession. J Periodontol 1989;60:316-9. |
|33.||Harris RJ, Harris AW. The coronally positioned pedicle graft with inlaid margins: A predictable method of obtaining root coverage of shallow defects. Int J Periodontics Restorative Dent 1994;14:228-41. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12]
[Table 1], [Table 2], [Table 3]