Clinical and radiographic evaluation of demineralized bone matrix (grafton) as a bone graft material in the treatment of human periodontal intraosseous defects.

PURPOSE: The purpose of this clinical trial was to evaluate the efficacy of demineralized bone matrix (DBM) as a bone graft material in the treatment of human intrabony periodontal defects as compared with control defects treated by open flap debridement (OFD) alone.
MATERIALS AND METHODS: A controlled clinical trial was carried out for a period of 9 months in 11 patients (4 males and 7 females) with an age group of 25-50 years, contributing to a total of 30 defects. The selected defects were then randomly divided in to experimental sites (OFD + DBM) and control sites (OFD alone). Probing depth, clinical attachment levels and position of the gingival margin were recorded at baseline 3, 6 and 9 months post-operatively. Standardized radiographs (parallel technique) were also documented at these recall intervals.
RESULTS: On completion of 9 months, the mean percentage of probing depth reduction achieved in the experimental sites and control sites was 61.70%, 23.86% respectively. The mean percentage of clinical attachment level gain was 61.34% and 19.37% in the experimental and control sites respectively. In the experimental sites recession was observed to a lesser extent.
CONCLUSION: The use of DBM was more effective than OFD in improving clinical parameters and radiographic bone fill as shown in the present study. However, there is a need for further long term studies.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Periodontal regeneration has been intriguing to the periodontists since ages. Numerous therapeutic approaches and regenerative materials have been reported in the literature for periodontal regenerative therapy.[12] Autogenous grafts are considered as a gold standard among graft materials because they are superior at retaining cell viability, they contain osteoblasts and osteoprogenitor stem cells and heal by osteogenesis they avoid the potential problems of histocompatibility differences and risk of disease transfer.[134] However, its availability is limited. In addition, it always requires a secondary surgical procedure with all its risk.[256]

Allografts are bone grafts taken for transplantation from one human to another. There are two types of allografts available including freeze-dried bone allograft and demineralized freeze-dried bone allograft (DFDBA).

The demineralization process of the graft exposes the bone inductive proteins located in the bone matrix such as bone morphogenetic protein-2 (BMP2) and BMP7, which are capable of inducing mesenchymal cells to differentiate into osteoblasts in vivo.[7] DFDBA also provides an osteoconductive surface for cell attachment.

A human demineralized bone matrix (DBM) combined with glycerol, was introduced to the orthopedic and periodontal communities more than 10 years ago. DBM is a human banked bone tissue that is prepared from tissue procured aseptically from a cadaver donor. During the procurement processing and packing, sterility testing is performed. The allograft is cleaned using 70% of alcohol, washed with purified water, sonicated, processed with surfactant and treated with polymyxin B sulfate, bacitracin and/or gentamicin. The bone is demineralized so that the resulting bone matrix has a residual calcium phosphate content level of <5%. Medical literature indicates that DBM is a safe and effective bone grafting material.[8]

The objective of this study is to evaluate both clinically and radiographically the efficacy of DBM as a bone graft material in the treatment of human intrabony periodontal defects as compared with control defects treated by open flap debridement (OFD) alone.

MATERIALS AND METHODS

A randomized controlled clinical trial with a split mouth design was conducted in which 11 patients (30 sites) with an age group between 25 and 50 years were selected from the out-patient Department of Periodontics, M.S. Rammaiah Dental College and Hospital. The study was approved by the ethical committee of M.S. Rammaiah Dental College and Hospital. Patients were explained about the pros and cons of the surgical procedure and the materials going to be used in the study and their consent was obtained with their signature in the informed consent form.

Inclusion and exclusion criteria

11 patients (4 males and 7 females) with a total of 30 sites were selected after the completion of the initial phase I therapy. Patients included in the study were having periodontal pocket with probing depth ≥5 mm and clinical attachment loss (CAL) ≥5 mm and radiographic evidence of periodontal osseous defects. Those who had undergone any type of regenerative periodontal therapy 6 months prior to the initial examination, patients with any systemic problem, which contraindicates periodontal surgical therapy, patients who are pregnant or lactating, who are allergic to materials and drugs used or prescribed in this study, who are medically compromised or under therapeutic regimen that decreased the probability of soft-tissue and bone healing and smokers were excluded from this study.

The selected sites (30 sites) were divided into control and experimental sites randomly with a split mouth design. The experimental sites were treated with OFD + DBM, whilst the control sites were treated with OFD alone. In all selected patients, surgical therapy was done 4-6 weeks after phase I therapy.

Vertical measurements for determination of probing depths, clinical attachment levels and gingival margin (GM) position were calculated from a fixed reference point (FRP) to the base of the pocket (BOP), FRP to cemento enamel junction (CEJ) and FRP to GM and recorded at baseline 3, 6 and 9 months post-operatively using University of North Carolina-15 graduated periodontal probe with the aid of a customized acrylic stent with grooves, which were placed on each defect site. Intraoral periapical radiographs using RadioVisio Graph and extended cone projection of each defect site was exposed at baseline, 3, 6 and 9 months post-operatively using long cone/paralleling technique and bone fill was measured using Image J software (Wayne Rasband, National institute of health-USA). All clinical and radiographic analysis was done by one operator only.

The following calculations were made from the clinical measurements recorded:

Probing depth

(FRP to BOP – FRP to GM)

Clinical attachment level

(FRP to BOP – FRP to CEJ)

GM position;

(FRP to CEJ – FRP to GM)

Surgical procedure

Surgical site was anesthetized with 1:200,000 lidocaine hydrochloride with adrenaline. After adequate anesthesia was achieved, a crevicular incision was given with No. 15 B.P blade [Figure 1]. A full thickness mucoperiosteal flap was raised following which the debridement was done in both groups of patients [Figures 2 and 3]. Only in the experimental sites DBM was placed in the defects [Figure 4]. In both groups, flaps were then repositioned and secured in place using 3-0 black braided silk and interrupted sutures were placed to obtained primary closure [Figure 5].

Figure 1

Incision placed

Figure 2

Control site defect

Figure 3

Experimental site defect

Figure 4

Pre-suturing and demineralized bone matrix graft placement

Figure 5

Sutures placed

The surgical areas were protected with a non-eugenol dressing [Figure 6]. All patients were prescribed systemic doxycycline hyclate 200 mg for the 1st day followed by 100 mg/day for another 6 days along with a combination of ibuprofen 400 mg and paracetamol 325 mg given twice daily for 3 days. Post-operative instructions were given to all patients and they were instructed to report to the department after 24 hr of surgery and then after 10 days.

Figure 6

Periodontal dressing placed

Statistical analysis

The Excel and SPSS (SPSS Inc., Chicago) software packages were used for data entry and analysis. The results were averaged (mean ± standard deviation [SD]) for each parameter [Table 1]. The Student t-test was used to determine whether there was a statistical difference between experimental and control groups in the parameters measured. One-way analyses of variance (ANOVA) were used to test the difference between groups. Comparison of two variance Sa2 and Sb2, estimated for two group Na and Nb subjects respectively was done using F-test. In all the above tests, a <0.05 was accepted as indicating statistical significance.

Table 1

Comparison of percentage changes in pocket depth measurements in the experimental group at different visits

RESULTS

All patients showed good compliance and the healing period was uneventful for both the treated groups, without showing any signs of inflammation, infection and swelling indicating the biocompatibility of the material (DBM) used.

Clinical parameter results

Probing depth measurements

Experimental group: The mean probing depth (±SD) in mm was 6.32 ± 1.38 at base line, 4.11 ± 0.94 at 3 months and 3.16 ± 0.76 at 6 months, 2.42 ± 0.72 at 9 months [Table 1, Graph 1]. The changes in the probing depth when compared to baseline were significant at 6 months and 9-month time interval [Figures 7 and 8].

Graph 1

Mean values of probing depth measurements of experimental and control groups at baseline, 3, 6, and 9 months

Figure 7

Experimental site probing depth at baseline

Figure 8

Experimental site probing depth at nine months

Control group: The mean probing depth (±SD) in mm was 5.74 ± 1.85 at base line, 4.53 ± 1.95 at 3 months, 4.16 ± 1.86 at 6 months, 4.37 ± 1.80 at 9 months [Table 2, Graph 1]. The changes in the probing depths when compared with the base line were not significant [Figures 9 and 10].

Table 2

Comparison of percentage changes in pocket depth measurements in the control group at different visits

Figure 9

Control site probing depth at baseline

Figure 10

Control site probing depth at nine months

The mean percentage of probing depth reduction achieved in the experimental group at 3, 6 and 9 months post-surgery was 34.96, 50.00 and 61.70 respectively. That achieved in the control group at 3, 6 and 9 months post-surgery was 21.08, 27.52 and 23.86 respectively. The difference between the experimental and control groups with respect these measurements were statistically significant at 6 and 9 months interval (P < 0.05) [Table 2a and Table 3].

Table 2a

Multiple comparisons dependent variable: Pocket depth (mm) (Bonferroni test)

Table 3

Comparison of percentage changes in pocket depth and clinical attachment level in experimental and control groups at different visits

Clinical attachment level measurements

The mean clinical attachment level in the experimental group was 6.26 ± 1.41 mm at base line, 4.05 ± 0.91 mm at 3 months, 3.11 ± 0.99 mm at 6 months and 2.42 ± 0.77 mm at 9 months [Table 4, Graph 2]. In the control group, it was 5.42 ± 1.81 mm at base line, 4.58 ± 0.21 mm at 3 months, 4.42 ± 1.77 mm at 6 months and 4.37 ± 1.80 mm at 9 months [Table 5, Graph 2]. The mean percentage of gain in clinical attachment level achieved in the experimental group at 3, 6 and 9 months post-surgery was 35.30, 50.31 and 61.34 respectively. The control group achieved a percentage gain of 15.49, 18.45 and 19.37 at 3, 6 and 9 months respectively. The difference between the experimental and control groups with respect these measurements were statistically significant at 6 months (P < 0.05) and 9 months interval (P < 0.001) [Tables 3 and 5a].

Table 4

Comparison of percentage changes in clinical attachment levels in the experimental group at different visits

Graph 2

Mean values of clinical attachment levels of experimental and control groups at baseline, 3, 6, and 9 months

Table 5

Comparison of percentage changes in clinical attachment levels in the control group at different visits

Table 5a

Multiple comparisons dependent variable: Clinical attachment level (mm) (Bonferroni test)

Changes in GM position

In the experimental group, only 2 of the 19 sites experienced a recession, in the control group 8 of the 11 sites experienced recession [Graph 3]. On comparing, the percentage of patients exhibiting changes in GM position in the experimental and control group, the difference was found to be statistically significant.

Graph 3

Mean values of the gingival margin positions of experimental and control groups at baseline, 3, 6, and 9 months

Radiographic assessment

The post-operative radiographs at 6 and 9 months showed bone fill in the experimental sites 60.8 ± 16.02 percentage and in control sites around 15.6 ± 8.35. However, material used in this study is radiolucent [Figures 11–14].

Figure 11

Control site radiographic assessment at baseline

Figure 14

Radiographic evaluation at 9 months – experimental site

Radiographic evaluation at 9 months – control site

Experimental site radiographic assessment at baseline

DISCUSSION

Although, regeneration has become a reality only to some extent, complete and true regeneration is still a goal to be achieved.

The best success rate in bone grafting was achieved with autogenous bones, it is considered as a gold standard because they are essentially living tissues with their cells intact. However, this means more morbidity and additional surgery. To overcome these problems, the allografts are gaining popularity for periodontal regeneration. The last few decades have seen the remarkable development of DBM as an osteogenic material. This material is biocompatible, biodegradable, osteoinductive, cost-effective, readily available from approved tissue banks and suitable for biomedical applications.[9]

The material used in this study is DBM in a putty form, it consists of 4% sodium hyaluronate and it is believed that the increased concentration of the sodium hyaluronate solution will increase the viscosity of the DBM putty, consequently allowing for a more manageable product for the clinician to work intraoperatively and more stable as a graft in its recipient site.[10]

In the present study, a group of 11 patients (4 males and 7 females) with an age group of 25-50 years and contributing to a total of 30 defects were selected and then randomly divided in to experimental (OFD + DBM bone graft material) and control sites (treated with OFD alone) with the help of clinical and radiographic methods.[11] The clinical parameters that were recorded included clinical attachment levels, probing depth and radiographs (were taken as suggested by Ramfjord).[12]

In this study, the experimental group showed statistically significant reductions in pocket depth at 6 and 9 months post-operatively from the base line. This was similar to the findings of Mellonig[13] Sepe et al.,[14] Quintero et al.,[15] and Richardson et al.,[16] who reported a reduction in mean probing depth between 50% and 65%. In our study, we found the probing depths reduced by 61.07%. The experimental site in this study exhibited significant gain in the clinical attachment level when compared with base line at the 6th and 9th month. The control group did not show any significant gain in clinical attachment levels. This was similar to findings of Pearson et al.,[17] Mellonig,[13] Sepe et al.,[14] Quintero et al.,[15] and Richardson et al.,[16]

Radiographic comparison of the surgical sites showed progressive changes in the appearance of the graft material from the time of placement to 3, 6 and 9 months. And similar radiographic findings have been reported by Werbitt[18] Quintero et al.,[15] Francis et al.,[19] The non-grafted sites did not show any discernible changes in radiographic appearance. No signs of root resorption were noted in any of the surgical sites.

DBM being radiolucent material was not apparent on the radiographs at all times.[20] So, the bone fill in the defects was easy to notice at different time intervals. For more than 50 years, bone grafts have been used to treat the osseous defects associated with periodontal disease. This therapy has been shown to be clinically successful when encompassed in a comprehensive care program based on effective daily plaque control by the patient and a professionally supervised periodontal maintenance program.

The result of the present study are consistent with Garrett's (1996) assessment who stated that in controlled clinical trials treating intraosseous defects with non-resorbable and absorbable synthetic graft materials have consistently demonstrated clinical advantages beyond that achieved by debridement alone.[21] Meta-analysis performed by Reynolds et al., (2003) on 12 studies showed greater CAL gain and a significantly greater probing depth reduction was reported for bone allograft treatment 0.43 mm, SD 2.25 compared with OFD.[222324]

CONCLUSION

The present clinical study was aimed to evaluate clinical gain in clinical attachment level, osseous defect fill and compare the clinical outcome using DBM bone graft with open flap surgery alone.

The following conclusions were drawn from the study:

There was a statically significant reduction in probing depths at the experimental (DBM) sites, than control sites (only OFD)

There was a greater and statistically significant percentage of gain in clinical attachment level at the experimental sites when compared with control sites

Inference of bone fill could be drawn from the change in the hard tissues viewed radiographically in the experimental group at 6 and 9 months.

Further long-term controlled studies are indicated toward evaluating the adjunctive benefits of DBM bone graft material with OFD in the treatment of human periodontal osseous defects.