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| ORIGINAL ARTICLE |
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| Year : 2016 | Volume
: 6
| Issue : 1 | Page : 11-17 |
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Periodontal regeneration by application of recombinant human bone morphogenetic protein-2 in human periodontal intraosseous defects: A randomized controlled trial
Kharidi Laxman Vandana1, Ganesh Singh1, Shobha Prakash1, Kala S Bhushan1, Neha Mahajan2
1 Department of Periodontics, College of Dental Sciences, Davangere, Karnataka, India
2 Department of Periodontics, Himachal Dental College, Sundernagar, Himachal Pradesh, India
| Date of Web Publication | 21-Jul-2016 |
Correspondence Address:
Kharidi Laxman Vandana
Department of Periodontics, College of Dental Sciences, Davangere, Karnataka
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2231-6027.186658
Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) technologies have been shown to significantly support alveolar bone. The purpose of this study was to explore the effect of rhBMP-2 following periodontal flap surgery in vertical defects on clinical and radiological parameters. Methods: A randomized double-blind controlled trial was carried out, wherein rhBMP-2 was used in the test group after open flap debridement (OFD). The control group was only OFD. The same examiner carried out both clinical and radiographic measurements at baseline, 6 and 9 months. Results: In rhBMP-2 + OFD sites, the probing pocket depth reduction was 1.45 ± 0.76, 2.50 ± 0.69 at 6 months and 9 months, respectively (both P < 0.001) and clinical attachment gain was 0.92 ± 0.76, 1.31 ± 0.48 at 6 months, and 9 months, respectively (both P < 0.001). Radiographic fill was 1.14 ± 0.73, 1.85 ± 0.83 at 6 months, and 9 months postoperatively (P < 0.001) and percentage of original defect resolved at 6 and 9 months was 40.2 ± 18.6, 60.1 ± 15.8, respectively. Conclusions: The periodontal therapy can include rhBMP-2 to enhance periodontal regeneration. The clinical and radiographic improvement are demonstrated in this study. Keywords: Bone morphogenetic, bone regeneration, clinical trials, interproximal vertical defects, periodontal regeneration, proteins
How to cite this article:
Vandana KL, Singh G, Prakash S, Bhushan KS, Mahajan N. Periodontal regeneration by application of recombinant human bone morphogenetic protein-2 in human periodontal intraosseous defects: A randomized controlled trial. Int J Oral Health Sci 2016;6:11-7 |
How to cite this URL:
Vandana KL, Singh G, Prakash S, Bhushan KS, Mahajan N. Periodontal regeneration by application of recombinant human bone morphogenetic protein-2 in human periodontal intraosseous defects: A randomized controlled trial. Int J Oral Health Sci [serial online] 2016 [cited 2023 Jun 4];6:11-7. Available from: https://www.ijohsjournal.org/text.asp?2016/6/1/11/186658 |
| Introduction | |  |
The ultimate goal in periodontal therapy is the creation of an environment that is conducive in maintaining the patient's dentition in health, comfort, and function. [1] Although number of treatment modalities are currently available, clinicians continue to seek more predictable regenerative therapies that are less technique sensitive, lead to faster tissue regeneration and are applicable to the broad array of periodontal defects encountered daily by the clinicians. [2] The synthetic barrier membranes have been used to encourage appropriate progenitor cell population of the wound site. [3]
With improving understanding of the molecular processes associated with tissue repair and regeneration, polypeptide growth factors applied to root surfaces have been used to facilitate periodontal regeneration. To date, these have included epidermal growth factor, fibroblast growth factor, insulin-like growth factor, platelet-derived growth factor, and tumor-derived growth factor. [4]
Bone, platelets, and variety of other cells and tissues naturally contain potent bioactive proteins termed as growth factors or morphogens. [5],[6] The two categories of molecules that have received greatest attention are the growth factors, which are primarily mitogenic (cell proliferative) and chemotactic (cell recruitment) agents and morphogens that act mostly by osteoinduction, i.e., causing the differentiation of stem cells into bone-forming cells. [5],[6],[7],[8],[9]
A new alternative to the treatment of bone defects came from the findings of Urist [10] and Reddi and Huggins, [11] who demonstrated that the devitalized and demineralized bone matrix are able to induce heterotrophic osteogenesis. The bone morphogenetic proteins-2 (BMPs), present in the interior of bone matrix, display osteogenic and osteoinductive properties that when released, induce the sequential process of formation of new bone tissue. BMPs represent a family of more than twenty-related proteins that are a part of transforming growth factor-β gene family. Discovery based on a bone-inductive potential sequestered in bone matrix, BMPs are today recognized to regulate principal functions in fetal and postfetal life. [12] Evidence on substantial bone and cementum regeneration following periodontal reconstructive surgery using recombinant human BMP-2 (rhBMP) was demonstrated in dogs. [13] Animal studies in rats and dogs have successfully demonstrated enhanced periodontal regeneration following the application of BMP-2 and BMP-7 in surgically created periodontal defects. [14],[15] In vitro experimentation has demonstrated that BMP-2 and BMP-7 can further induce bone and cementum formation as well as osteoblastic and chondrocytic differentiation. [16],[17]
Medline search using the key words "intrabony," "vertical," "rhBMP-2," "humans," and "periodontal regeneration" revealed few studies on the use of rhBMP-2 material for treatment of human periodontal vertical osseous defects. rhBMP-2 (Altis OBM™ ) is a porcine derived medical device that comes packed in a syringe in a lyophilized powder form, and once reconstituted with sterile water for injection, it transforms into an osteoinductive paste which can be injected and shaped as per requirements. Therefore, here, an attempt was made to evaluate clinically and radiographically the effectiveness of rhBMP-2 (Altis OBM™) in the treatment of human periodontal intraosseous defects.
| Methods | | |
Patients and defect treatment
In this 9 months follow-up, randomized, double-masked study, 32 subjects (18 males and 14 females) between the age group of 35-55 years who were undergoing periodontal therapy at Department of Periodontics, College of Dental Sciences, Davangere, India were selected to be included in the study. The research protocol was initially submitted to the Institutional Ethical Committee and Review Board of the College of Dental Sciences, Davangere. After ethical approval, all participants were verbally informed, and written informed consent was obtained for participation in the study. Subjects diagnosed as having chronic periodontitis based on AAP 1991 classification were selected. Patients with an interproximal probing depth (PD) ≥5 mm after Phase I therapy (scaling and root planing) in asymptomatic teeth with vertical depth on intraoral periapical (IOPA) were included in the study. Patients were systemically healthy, and there were no contraindications to periodontal therapy. The following were the exclusion criteria: (1) Aggressive periodontitis, (2) known systemic illness, (3) medications known to affect periodontal therapy, (4) smoking/tobacco use, (5) pregnancy or lactation, and (4) insufficient platelet count (<200,000/mm 3 ). Those having unacceptable oral hygiene (plaque index [PI] >1.5) after a reevaluation of Phase I therapy, those who had undergone periodontal therapy 3 months before the study and those allergic to animal products were excluded from the study. In addition, teeth with furcation defects, gingival recession, nonvitality, and/or mobility of at least Grade II were also excluded from the study.
Presurgical protocol
All the selected patients, following an initial examination and treatment plan discussion, were given detailed instructions in self-performed plaque control measures and were subjected to Phase I periodontal therapy. Occlusal adjustments were performed by selective grinding when required. 2-3 weeks after Phase I therapy, the oral hygiene status and the tissue response were evaluated using plaque and gingival indices (GIs). The patients with acceptable oral hygiene were subjected to the surgical procedure. The selected sites were divided randomly (computer generated tables) into the control and test groups. The control group consisted of the sites treated with open flap debridement (OFD), whereas the test sites were treated with OFD with rhBMP-2 (Altis OBM™).
Altis OBM™ (Altis Biologics Pvt. Ltd., South Africa), a composite of three porcine bone matrix derived protein fractions which was provided as a lyophilized powder in a sterile syringe. It consisted of porcine bone collagen, bone gelatin, and BMP (3-12 mg). It is an implantable biomaterial (biological medicine) intended as a bone graft substitute with bioresorbable, osteoinductive nature, and also provides scaffolding effect. [18]
Clinical and radiographic measurements
On the day of the surgical procedure, baseline clinical measurements were recorded by calibrated examiner masked to the treatment; measurements were repeated 6 and 9 months postsurgery using the same probe. The outcome variables included: PI, GI, probing pocket depth (PPD) from the gingival margin, and clinical attachment level (CAL) from the apical level of customized acrylic stents with grooves to ensure a reproducible placement of the periodontal probe. The defects were randomly assigned to one of the treatments at the time of surgery. Measurements were made with a UNC-15 probe (Hu-Friedy, Michigan, USA) and recorded to the nearest millimeter.
All IBDs (Intrabony Defects) were evaluated at baseline, 6 and 9 months postoperatively. Radiographs were taken at the initial examination, 6 and 9 months postsurgery were evaluated by the same investigator who performed the clinical measurements. Standardized radiographs were taken using the paralleling technique and holders. The following linear distances were measured in millimeters: The distance from the alveolar crest (AC) to the base of the defect (BD), the distance from the cement-enamel junction (CEJ) to the BD, and distance from CEJ to AC. The most coronal area where periodontal ligament (PDL) maintained an even width was identified to measure the most apical extension of the intrabony defect.
The same examiner masked to the procedure category performed all measurements. The differences between the 9 months, 6 months, and baseline values for CEJ-BD indicated the amount of hard tissue fill within the osseous defect. The differences between CEJ-BD and CEJ-AC recorded at baseline, 6 and 9 months were represented the depth of the intrabony defect and amount of crestal bone resorption, respectively. Defect resolution was defined as the percentage change in AC-BD. The digitized radiographic measurements using CorelDraw 10 was used to record the changes in the bony defects. [19] The position of the CEJ was identified as described by Schei et al. [20] The most coronal area where the PDL maintained an even width was identified as the most apical extent of the intrabony defect.
Surgical protocol
The proposed surgical area was anesthetized using local anesthetic. Using sulcular incisions, buccal and lingual full thickness (mucoperiosteal) flaps were elevated. Following reflection of the mucoperiosteal flap, complete debridement was carried out to remove all granulation tissue associated with osseous defect. The surgical area was irrigated with normal saline and carefully inspected to ensure that the procedure had been completed adequately in both controlled and test sites. Only OFD was performed at control site.
The test site received rhBMP-2 bone graft substitute. The preparation of rhBMP-2 was initiated approximately 15 min before application. Once the implant was ready, it was placed immediately on the exposed root surface so that the implant material (rhBMP-2) touches the root surface. Care was taken to isolate the root surface and the defect site from saliva during grafting procedures. The gingival flaps were secured with interdental sutures (3-0 black braided silk suture, ETHICON™) to achieve complete coverage of the surgical site with optimal adaptation of the soft tissue. The area was protected with noneugenol periodontal dressing (Vocopac). Amoxicillin - 500 mg tid for 5 days and paracetamol - 625 mg bid for 3 days was prescribed for the management of postoperative discomfort. Postoperative instructions were given, and the patients were advised to rinse with 0.2% of chlorhexidine solution for 4-6 weeks postoperatively. In addition, any adverse effects local or systemic were recorded. Sutures were removed after 7-10 days.
Postsurgical measurements
The clinical measurements were repeated as described earlier. Soft and hard tissue evaluation was performed 6 and 9 months postsurgery. Soft tissue measurements were repeated with previously used acrylic stents. For hard tissue reevaluation, the second IOPA of the same study site was performed using long cone/paralleling technique and intrabony defect measurement was reassessed at 6 and 9 months. The IOPA of each site was digitized using a flatbed scanner with a scanning resolution of 600 dpi (UMAX - ASTRA 1220S). The scanned images stored in JPEG format were transferred to corel draw ten. For measurements, connector line tool was used. The cementoenamel junction, the base of the defect and the crest of alveolar bone were located on the images. Using the connector line tool, a line was drawn from CEJ to base of the defect. The length of the line was displayed in the property box of the software. The software then displayed the distance between these two points. The same procedure was repeated to obtain the distance between CEJ and AC. Subtracting the two measurements, the depth of osseous defect was obtained. [19]
Statistical analysis
Results are expressed as mean ± standard deviation and percentages. For clinical parameters, intra- and inter-group comparisons were made using paired t-test and unpaired t-test, respectively. For radiographic parameters, nonparametric methods were used for analysis. Wilcoxons signed-rank test was used for intragroup and Mann-Whitney test for intergroup comparisons.
| Results | | |
All 32 patients completed the study and experienced no adverse reactions related to treatment. Postsurgical healing was uneventful in all the 32 sites involved in the study.
Clinical measurements
At baseline, there was no significant difference in the test (BMP) and control groups (OFD) for PPD and CAL. The PD reduced significantly within both groups from baseline to 6 and 9 months. The pocket depth reduction was not significant between the groups at 6 months (P = 0.95). At 9 months, the pocket depth reduced from 6.90 ± 0.85 mm to 4.40 ± 0.60 mm in the BMP group as compared to OFD, which was statistically significant (P < 0.05) [Table 1]. | Table 1 : Comparison of probing pocket depth between test and control groups at base line, 6 and 9 months postsurgically
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The gingival thickness at selected sites was similar in both the groups ranging from 1 to 1.5 mm. On gingival margin position (GMP) examination, there was no apical shift/gingival recession in treated sites postoperatively.
The improvement in CAL was highly significant within the groups from baseline to 6 and 9 months. The difference in CAL improvement was not significant at 6 months between the groups. However, at 9 months, it was significant (P < 0.05) in BMP group as baseline CAL reduced from 5.55 ± 1.05 mm to 3.65 ± 1.14 mm [Table 2]. | Table 2: Comparison of clinical attachment level between test and control groups at base line, 6 and 9 months postsurgically
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Radiographic measurements
In BMP group, at 6 months, the initial defect depth of 2.87 ± 1.03 mm significantly reduced to 1.73 ± 0.98 mm (P < 0.001); percentage fill of original defect was 39.1 ± 21.2 and percentage of original defect resolved was 40.2 ± 18.8. At 9 months, the initial defect depth of 2.87 ± 1.03 significantly reduced to 1.02 ± 0.7 (P < 0.001); percentage fill of original defect was 66.9 ± 22, and percentage of original defect resolved was 60.1 ± 15.8 [Table 3], [Table 4] and [Figure 1], [Figure 2] and [Figure 3]. | Figure 1: Baseline radiograph test group (recombinant human bone morphogenetic protein-2 + open flap debridement)
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 | Figure 2: Six months postoperative radiograph test group (recombinant human bone morphogenetic protein-2 + open flap debridement)
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 | Figure 3: Nine months postoperative radiograph test group (recombinant human bone morphogenetic protein-2 + open flap debridement)
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 | Table 3: Comparison of mean radiographic changes between test and control groups 6 months postsurgery
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 | Table 4: Comparison of mean radio graphic changes between test and control groups 9 months postsurgery
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In the OFD group, initial defect reduction, percentage fill of original defect, and original defect resolved at 6 and 9 months were statistically significant. The AC changes at 6 months were not significant between the groups. Intergroup comparison revealed a significant amount of bone fill in BMP group than in OFD group at 6 (P < 0.002) and 9 months (P < 0.001). The percentage of original defect resolved was highly significant in BMP group at 6 and 9 months (P < 0.001) [Table 3] and [Table 4].
| Discussion | | |
In the periodontal regenerative medicine, functions of the growth factors and their interaction with the extracellular matrix and cells are better understood through molecular and cellular biology. The BMPs are considerably involved in the healing of surgical wounds, especially in periodontal regeneration, since they initiate formation of new bone tissue by stimulating the differentiation of undifferentiated mesenchymal cells in osteoblasts. [21] The formation of new bone in surgically created defects treated with BMPs has been reported in a microscopic study.
Microscopic studies have showed the formation of new cementum, PDL and bone neoformation by application of rhBMP-2 [22],[23] and other BMPs. [24],[25] Many microscopic studies have supported the premise that the BMPs provide regeneration of the tooth supporting apparatus, including the cementum, PDL, and alveolar bone. [22],[23],[24],[25],[26],[27]
Based on above study reports and considering few human clinical studies on rhBMP-2, this study attempted the use of rhBMP-2 in test sites and compared with OFD at control site.
Guimaraes et al. reported the treatment of human intrabony defects using pooled BMP + guided tissue regeneration (GTR) in 15 patients with 10 pairs of intrabony defects and demonstrated no significant difference between test (BMP + GTR) and control groups at 6 months in PPD reduction and CAL improvement. [28] The drawback of this study was done over 6-month period without the radiographic assessment. However, this study was done for 9-month period and evaluated both clinically and radiographically.
The amount of rhBMP-2 used was 3-12 mg, [18] which was adequate to bring about clinically significant changes in test sites. The PD depth reduction and CAL improvement showed no significant difference at 6 months between BMP (test) and OFD (control) groups. However, at 9 months, there was a significant reduction of PD and CAL improvement in BMP-treated sites than the control sites which were supported by significant radiographic changes in bony defects in this study.
Most of the clinical trials fail to report postoperative gingival recession which is influenced by gingival thickness. The influence of gingival thickness (<1 mm and >1 mm) on GMP is reported by Vandana and Gupta. [29] It has been stated that gingival thickness of <1 mm is prone for posttreatment gingival recession than >1 mm gingival thickness. The adequate gingival thickness of 1-1.5 mm in the current study resulted in no postoperative recession at both control and test sites. Hence, it is recommended to select adequate gingival thickness at surgical sites to minimize postoperative gingival recession.
The findings of this study suggest that use of rhBMP-2 provided pocket depth reduction, CAL improvement and significant radiographic enhancement of original defect resolution of intrabony defects at 9 months. No adverse reactions were found locally or systemically in both the groups. Further studies to evaluate the effectiveness of rhBMP in aggressive periodontitis subjects and comparative studies of this newly introduced material to other products with similar regenerative potential like emdogain, platelet-rich fibrin should be undertaken.
| Conclusions | | |
The results obtained in this study suggest that rhBMP performs effectively in intrabony defects, providing clinical reduction in pocket depth, improvement in CAL as well as radiographic defect depth fill and defect resolution.
Acknowledgment
We sincerely thank Altis OBM, South Africa for providing the test material free of cost to the authors who self-funded this clinical trial.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Nasr HF, Aichelmann-Reidy ME, Yukna RA. Bone and bone substitutes. Periodontol 2000 1999;19:74-86.  |
| 2. | Garrett S. Periodontal regeneration around natural teeth. Ann Periodontol 1996;1:621-66. |
| 3. | Wikesjö UM, Lim WH, Thomson RC, Cook AD, Wozney JM, Hardwick WR. Periodontal repair in dogs: Evaluation of a bioabsorbable space-providing macroporous membrane with recombinant human bone morphogenetic protein-2. J Periodontol 2003;74:635-47. |
| 4. | Bartold PM, Shi S, Gronthos S. Stem cells and periodontal regeneration. Periodontol 2000 2006;40:164-72. |
| 5. | Lynch SE. Introduction. In: Lynch SE, Marx RE, Nevins M, Lynch LA, editors. Tissue Engineering: Applications in Oral and Maxillofacial Surgery and Periodontics. 2 nd ed. Chicago: Quintessence Publishing; 2006. p. 11-5. |
| 6. | Marx RE. Platelet-rich plasma: A source of multiple autologous growth factors for bone grafts. In: Lynch SE, Genco RJ, Marx RE, editors. Tissue Engineering: Applications in Maxillofacial Surgery and Peridontics. Chicago: Quintessence Publishing; 1999. p. 71-82. |
| 7. | Bolander ME. Regulation of fracture repair by growth factors. Proc Soc Exp Biol Med 1992;200:165-70. |
| 8. | Andrew JG, Hoyland JA, Freemont AJ, Marsh DR. Platelet-derived growth factor expression in normally healing human fractures. Bone 1995;16:455-60. |
| 9. | Fujii H, Kitazawa R, Maeda S, Mizuno K, Kitazawa S. Expression of platelet-derived growth factor proteins and their receptor alpha and beta mRNAs during fracture healing in the normal mouse. Histochem Cell Biol 1999;112:131-8. |
| 10. | Urist MR. Bone: Formation by autoinduction. Science 1965;150:893-9. |
| 11. | Reddi AH, Huggins C. Biochemical sequences in the transformation of normal fibroblasts in adolescent rats. Proc Natl Acad Sci U S A 1972;69:1601-5. |
| 12. | Hogan BL. Bone morphogenetic proteins: Multifunctional regulators of vertebrate development. Genes Dev 1996;10:1580-94. |
| 13. | Kinoshita A, Oda S, Takahashi K, Yokota S, Ishikawa I. Periodontal regeneration by application of recombinant human bone morphogenetic protein-2 to horizontal circumferential defects created by experimental periodontitis in beagle dogs. J Periodontol 1997;68:103-9. |
| 14. | King GN, King N, Cruchley AT, Wozney JM, Hughes FJ. Recombinant human bone morphogenetic protein-2 promotes wound healing in rat periodontal fenestration defects. J Dent Res 1997;76:1460-70. |
| 15. | Giannobile WV, Ryan S, Shih MS, Su DL, Kaplan PL, Chan TC. Recombinant human osteogenic protein-1 (OP-1) stimulates periodontal wound healing in class III furcation defects. J Periodontol 1998;69:129-37. |
| 16. | Asahina I, Sampath TK, Nishimura I, Hauschka PV. Human osteogenic protein-1 induces both chondroblastic and osteoblastic differentiation of osteoprogenitor cells derived from newborn rat calvaria. J Cell Biol 1993;123:921-33. |
| 17. | Yamaguchi A, Katagiri T, Ikeda T, Wozney JM, Rosen V, Wang EA, et al. Recombinant human bone morphogenetic protein-2 stimulates osteoblastic maturation and inhibits myogenic differentiation in vitro. J Cell Biol 1991;113:681-7. |
| 18. | Altis OBM™Company Literature: Expert Opinion to Altis Biologics (Pty) Ltd., on Safety Assessment of Altis OBM for Proposed Clinical Trial, Protocol Number ALTIS 001/2005. |
| 19. | Vandana KL, Shah K, Prakash S. Clinical and radiographic evaluation of Emdogain as a regenerative material in the treatment of interproximal vertical defects in chronic and aggressive periodontitis patients. Int J Periodontics Restorative Dent 2004;24:185-91. |
| 20. | Schei O, Waerhaug J, Lovdal I, Arno A. Alveolar bone loss as related to oral hygiene and age. J Periodontol 1959;30:7-16. |
| 21. | Zaman KU, Sugaya T, Kato H. Effect of recombinant human plated-derived growth factor-BB and bone morphogenetic protein-2 application to demineralized dentin on early periodontal ligament cell response. J Periodontal Res 1999;34:244-50. |
| 22. | Sasaki M, Kato H, Kuboki Y. A study of periodontal regenerative therapy using bone morphogenetic protein (BMP)-treatment of monkey's furcation involvement using collagen membrane as a spacer. J Jpn Soc Periodontol 1996;38:428-46. |
| 23. | Sigurdsson TJ, Nygaard L, Tatakis DN, Fu E, Turek TJ, Jin L, et al. Periodontal repair in dogs: Evaluation of rhBMP-2 carriers. Int J Periodontics Restorative Dent 1996;16:524-37. |
| 24. | Ripamonti U, Heliotis M, van den Heever B, Reddi AH. Bone morphogenetic proteins induce periodontal regeneration in the baboon ( Papio ursinus). J Periodontal Res 1994;29:439-45. |
| 25. | Ripamonti U, Heliotis M, Rueger DC, Sampath TK. Induction of cementogenesis by recombinant human osteogenic protein-1 (hop-1/bmp-7) in the baboon ( Papio ursinus). Arch Oral Biol 1996;41:121-26. |
| 26. | Bowers G, Felton F, Middleton C, Glynn D, Sharp S, Mellonig J, et al. Histologic comparison of regeneration in human intrabony defects when osteogenin is combined with demineralized freeze-dried bone allograft and with purified bovine collagen. J Periodontol 1991;62:690-702. |
| 27. | King GN, King N, Hughes FJ. Effect of two delivery systems for recombinant human bone morphogenetic protein-2 on periodontal regeneration in vivo. J Periodontal Res 1998;33:226-36. |
| 28. | Guimarães Mdo C, Passanezi E, Sant'ana AC, Greghi SL. Pool of bovine morphogenetic proteins and guided tissue regeneration in the treatment of intrabony periodontal defects: I-Clinical measurements. J Appl Oral Sci 2004;12:70-7. |
| 29. | Vandana KL, Gupta I. The relation of gingival thickness to dynamics of gingival margin position pre- and post-surgically. J Indian Soc Periodontol 2016;20:167-73. [ PUBMED]  |
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]
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