Clinical and radiographic evaluation of nanocrystalline hydroxyapatite with or without platelet-rich fibrin membrane in the treatment of periodontal intrabony defects.

BACKGROUND: Nano-sized ceramics may represent a promising class of bone graft substitutes due to their improved osseointegrative properties. Nanocrystalline hydroxyapatite (NcHA) binds to bone and stimulate bone healing by stimulation of osteoblast activity. Platelet-rich fibrin (PRF), an intimate assembly of cytokines, glycan chains, and structural glycoproteins enmeshed within a slowly polymerized fibrin network, has the potential to accelerate soft and hard tissue healing. The present study aims to explore the clinical and radiographical outcome of NcHA bone graft with or without PRF, in the treatment of intrabony periodontal defects.
MATERIALS AND METHODS: In a split-mouth study design, 20 patients having two almost identical intrabony defects with clinical probing depth of at least 6 mm were selected for the study. Selected sites were randomly divided into two groups. In Group I, mucoperiosteal flap elevation followed by the placement of NcHA was done. In Group II, mucoperiosteal flap elevation, followed by the placement of NcHA with PRF was done. Clinical and radiographic parameters were recorded at baseline and at 6-month postoperatively.
RESULTS: Both treatment groups showed a significant probing pocket depth (PPD) reduction, clinical attachment gain, increase bone density 6-month after surgery compared with baseline. However, there was a significantly greater PPD reduction and clinical attachment gain when PRF was added to NcHA.
CONCLUSION: The NcHA bone graft in combination with PRF demonstrated clinical advantages beyond that achieved by the NcHA alone.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

The ultimate goal of periodontal therapy is the regeneration of periodontal tissues that have been destroyed due to periodontal disease. Periodontal regeneration is the reconstruction of the lost tissues as evidenced histologically in the formation of new cementum, new alveolar bone, and functionally oriented periodontal ligament. Different modalities have been proposed to obtain regeneration of periodontal tissues employing various bone grafts, bone substitute materials, guided tissue regeneration (GTR), combination of bone grafts or bone substitutes with GTR and growth factors.[123456]

Hydroxyapatites (HAs) represent a family of bone grafting materials with a high degree of biocompatibility that is largely attributable to its presence in natural calcified tissue.[7] Preliminary experimental studies have shown that nano-sized ceramics may represent a promising class of bone graft substitutes due to their improved osseointegrative properties.[89] Accordingly, a synthetic nanocrystalline hydroxyapatite (NcHA) bone graft has been introduced for augmentation procedures in intrabony defects. Advantages of NcHA material are osteoconductivity, bioresorbablity, and close contact. A special feature of nanostructured materials is an extremely high number of molecules on the surface of the material. When the NcHA was used as a bone graft substitute, rapid healing of critical size defects was observed in animal experiments and in human applications.[10] NcHA binds to bone and stimulate bone healing by stimulation of osteoblast activity.[11] NcHA has been used for the treatment of metaphyseal fractures in orthopedic surgery,[12] ridge augmentation,[13] and peri-implantitis lesions.[14]

Platelet-rich plasma (PRF) is an autologous concentration of platelets in plasma.[1516] PRP has been used to enhance the clinical outcome obtained by using bone grafts with and without GTR in the treatment of intrabony defects. PRF, a second-generation platelet concentrate has been introduced by Choukroun et al. in 2001 that has several advantages over PRP.[17] Choukroun's PRF, a second-generation platelet concentrate is an autologous leukocyte and PRF material. This is produced in a totally natural manner, without using anticoagulant during blood harvest nor bovine thrombin and calcium chloride for platelet activation and fibrin polymerization. The absence of anticoagulant implies the activation in a few minutes of most platelets of the blood sample in contact with the tube walls and release of the coagulation cascades. The protocol is very simple and of low cost. PRF is a matrix of autologous fibrin, in which are embedded intrinsically a large quantity of platelet and leukocyte cytokines during centrifugation leading to their progressive release over time (7-11 days), as the network of fibrin disintegrates.[1718]

This study was designed to evaluate the efficacy of NcHA bone replacement graft with or without PRF, in the treatment of intrabony periodontal defects.

MATERIALS AND METHODS

Patient selection

In this 6-month follow-up interventional study, a total of 20 systemically healthy patients undergoing periodontal therapy at the Department of Periodontology, Faculty of Dentistry, 6 October University and Tanta University from February 2013 to December 2013 were selected for the study. Intraoral periapical radiographs were taken to confirm the presence of suitable bony defects for the selection of subjects. All participants received full written and verbal information about the study and signed an informed consent form. This study was approved by the Research Ethical Committee of Tanta University. There were no conflicts of interest in this study. The inclusion criteria were the presence of two almost identical interproximal intrabony defects, one on either side of the arch based on radiographic observations with clinical probing depth ≥6 mm in teeth. Exclusion criteria for this study included:

Any systemic disease that affect the periodontium and contraindicate for periodontal surgery

Patients are having insufficient platelet count for PRF preparation, patients with coagulation defect or anticoagulation treatment

Pregnant, lactating mothers, postmenopausal women.

People who take antiinflammatory drugs, antibiotics or vitamins within the previous 3 months

People who use mouthwashes regularly

Heavy smoking (>10 cigarettes/day)

History of alcohol abuse

Unacceptable oral hygiene after the re-evaluation of phase I therapy were excluded from the study.

A general assessment of selected subjects was made through their history, clinical examination and routine investigations. All subjects were treated with the initial phase I therapy involving oral hygiene instructions, scaling and root planning. Following phase I therapy the subjects were re-evaluated after 4 weeks, and those who still satisfied the selection criteria were finally taken up for the study.

Materials

Nano-bone® (ARTOSS GmbH friedrich-Barnewitz-straBe 3118119 Rostock/Germany).

Platelet-rich fibrin preparation

The PRF was prepared in accordance with the protocol developed by Dohan et al.[18] Just prior to surgery, intravenous blood (by venipuncturing of the antecubital vein) was collected in 10-ml sterile tube without anticoagulant and immediately centrifuged in centrifugation machine at 3,000 revolutions (approximately: 400 g)/min for 10 min. Blood centrifugation immediately after collection allows the composition of a structured fibrin clot in the middle of the tube, just between the red corpuscles at the bottom and acellular plasma (Platelet-poor plasma [PPP]) at the top.[19] PRF was easily separated from red corpuscules base (preserving a small red blood cell layer) using a sterile tweezers and scissors just after removal of PPP and then transferred onto glass slide and put another glass slide over the PRF to squeeze and transfer it to membrane.

Patient groups

Selected sites were randomly divided into two groups. In Group I, mucoperiosteal flap elevation followed by the placement of nano-bone® with PRF was done. In Group II, mucoperiosteal flap elevation, followed by the placement of nano-bone® was done [Figure 1]. Recall appointments were made at 7 days, 30 days, and then at 3 months and 6-month.

Figure 1

(a and b) Reflection of mucoperiosteal flap and nano–HA filled in the intrabony defect and covered by PRF mrmbrane (Group I); (c and d) Reflection of mucoperiosteal flap and nano-HA filled in the defect (Group II)

Clinical measurements

The periodontal status of the subjects was determined by recording:

Plaque index (PI)[20]

Gingival index (GI)[21]

Probing pocket depth (PPD)[22]

Clinical attachment level (CAL).[21]

All clinical parameters were recorded at baseline and at 3 and 6-month post treatment.

Radiographic examination

Periapical dental radiographs using long cone paralleling technique were obtained from each patient for the selected site before treatment and at 6-month after treatment. All radiographs were obtained by the same X-ray machine (ORIX 70-ARDET, Italy); using 70 kvp; 8 mA, and with a fixed exposure time of 0.8 s. The radiographs were developed using automatic developer machine (DURR-AUTOMATIC, XR 24-II, Italy). Then, the processed periapical radiographs were digitized using a full page, color flatbed computer scanner (with optional transparency adaptor) connected to an IBM compatible personal computer equipped with Pentium IV processor.

The region of interest was determined in each radiograph as the region that begins 1 mm below the cement-enamel junction and down toward the root apex 7 mm in length. The gray levels were carried out using the computer graphic software Adobe Photoshop version 7 (Adobe Systems Incorporated, 345 Park Avenue, San Jose, California 95110, USA).

Statistical analysis

All the results were tabulated and statistically analyzed using computer software named the Statistical Package for Social Science (SPSS version 16, Chicago, Illinois). Comparison within and between the studied groups performed with independent samples Student's t-test paired t-test and at a level of 5% significance.

RESULTS

The mean age of the patients in Group I was 44.25 ± 8.45 years old, whereas in Group II, it was 39.70 ± 6.36 years old with no significant difference between the two groups (P > 0.05). In the meantime, the mean baseline values of PI, GI, PPD, and CAL and bone density (BD) showed no significant difference between the two groups (P > 0.05).

Clinical results

In the present study both treatment modalities achieved a statistically significant reduction of the mean PI and GI scores, which continued up to the end of the 6-month evaluation period when compared to the mean baseline values (P < 0.01). However, at all evaluation points the reduction in PI and GI scores were no statistically significant different between two groups [P > 0.01, Table 1]. The mean PI and GI score remained <1 throughout 6-month period. Thus, in general, the patients showed good oral hygiene throughout the study.

Table 1

Mean values of PI, GI, PPD, CAL, among the study groups at baseline and 6 months after treatment and BD among the study groups at baseline and 6-month after treatment

Furthermore, results of Groups I and II revealed that there was a statistically significant reduction in the mean PPD and CAL measurements at 6-month post treatment compared with the mean baseline values. However, at 6-month the reduction in PPD and CAL scores was statistically different and more obvious following the PRF therapy of the Group I compared with Group II [P < 0.01, Table 1].

Bone density results

In both groups, data showed a statistically significant rise in the mean values of BD after 6-month follow-up compared with baseline values (P < 0.001). At 6-month the Group I showed more statistically significant rise in BD values as compared to the Group II [P < 0.001; Table 1 and Figures 2 and 3].

Figure 2a and b

Photograph showing the gray level of bone at baseline and after 6 months post treatment in Group I

Figure 3a and b

Photograph showing the gray level of bone at baseline and after 6 month post treatment in Group II

DISCUSSION

Therapeutic approaches for managing periodontitis involve various modalities to arrest the progression of periodontal tissue destruction, as well as regenerative techniques intended to restore structures destroyed during the disease process.[23]

Nano-sized HP may have other special properties due to its small size and huge specific surface area. This nano-size leads to a significant increase in protein adsorption and osteoblast adhesion on the nano-sized ceramic.[24]

Platelet-rich fibrin (PRF) is in the form of platelet gel and can be used in conjunction with bone grafts, which offers several advantages including promoting wound healing, bone growth and maturation, graft stabilization, wound sealing, and hemostasis and improving the handling properties of graft materials.[25] The present study evaluated the clinical and radiographic outcomes obtained following treatment of intrabony periodontal defects with nano-HA with or without PRF. It was designed as a split-mouth investigation to facilitate the comparison of two treatment procedures by eliminating patient-specific characteristics that might have an impact on the results of regenerative surgeries.[2627] The split-mouth design has been considered adequate for evaluating regenerative procedures in a recent systematic review.[28] Wenzel et al.,[29] reported that, no increased bone fill between 6 and 12 months may support the 6-month radiographic analysis of the present study.

In the present study, both treatment modalities achieved a statistically significant reduction in the mean plaque and GI scores at the treated sites during follow-up evaluations compared with baseline scores. At all evaluation periods, the reduction in PI and GI in both groups may be attributed to mechanical oral hygiene procedures.

A significant improvement in PPD reduction, CAL gain, and radiographic defect fill was observed in both test and control group at 6-month postoperatively compared with baseline which was favoring to the Group I. In Group II, the reduction in PPD and the CAL gain was in accordance with the previous reported study by Kasaj et al.,[30] that evaluated the clinical efficacy of NcHA paste in intrabony defects and reported PPD reduction of 3.9 mm ± 1.2 mm and CAL gain of 3.6 mm ± 1.6 mm. Meanwhile, Schwarz et al.,[14] evaluated the healing of intrabony peri-implantitis defects following application of two types of HA; a NcHA or a bovine-derived xenograft in combination with a collagen membrane (BDX1BG). Postoperative wound healing revealed that NHA compromized initial adhesion of the mucoperiosteal flaps in all patients. At 6-month after therapy, showed that CAL changed from 7.5-1.0 mm to 5.2-0.8 mm.

At all evaluation points, there was statistical significant reduction in PPD, gain in CAL and increased BD in Group I compared with Group II. This may be due to the effect of combination technique (BG + PRF) used in the present study. Kiliç et al.,[31] demonstrated that the combination of HA collagen bone graft with expanded polytetrafluoroethylene membrane resulted in higher PPD reduction (5.85 mm) and greater CAL gain (3.80 mm) compared with the test group results. Furthermore, This result in agreement with Singh et al.,[32] who found that the NcHA bone graft in combination with the collagen membrane demonstrated clinical advantages beyond that achieved by open flap debridement alone.

It was suggested that intrabony defect configuration influences the results after GTR, and larger amounts of CAL gain were reported following GTR treatment.[33] A systematic review concluded that in two-wall intrabony defect models of periodontal regeneration, the additional use of grafting material gave superior histological results of bone repair to barrier membranes alone.[34]

Clinical trials suggest that the combination of bone graft along with the growth factors in the PRF may be suitable to enhance the BD because PRF is a rich source of platelet-derived growth factor, transforming growth factors, and insulin-like growth factors.[25]

Platelet-rich fibrin can serve as a resorbable membrane, which can be used in preprosthetic surgery and implantology to cover bone augmentation site.[35] Since the surface of PRF membrane is smoother, it can cause superior proliferation of human periosteal cells thereby enhancing bone regeneration.[36] The progressive polymerization mode of coagulation in PRF helps in the increased incorporation of the circulating cytokines into the fibrin meshes (intrinsic cytokines) which helps in wound healing by moderating the inflammation.[3637]

Shivashankar et al.,[38] used HA and PRF barrier membrane in the treatment of large periapical lesion. Radiologically, the HA crystals have been completely replaced by new bone at the end of 2 years. They hypothesize that the use of PRF in conjunction with HA crystals might have accelerated the resorption of the graft crystals and would have induced the rapid rate of bone formation.

Simple, easy, fast and cost-effective process of PRF preparation without any biochemical involvements hold the major advantage over other derivatives. Also the physiologic functional fibrin matrix has the ability to sustain and progressively release growth factors, cytokines and leukocytes in the surrounding tissues as the matrix degrades over time. All these factors help make PRF the most significant in fibrin technology and endogenous regenerative therapy.[39]

CONCLUSION

Nanocrystalline hydroxyapatite is a promising bone graft in the treatment of intrabony defect. Adjunctive use of PRF membrane in combination with NcHA bone graft resulted in clinically, radiographically and statistically significant compared with NcHA bone graft alone, in terms of PPD reduction, CAL gain, and increase BD.

RECOMMENDATION

The combination therapy of PRF with commercially available bone grafts is a promising technic that should be used to enhance the regeneration.