The comparative efficacy of decalcified allogenic bone matrix and intra-oral free osseous autografts in the treatment of periodontal intrabony defects.

BACKGROUND AND OBJECTIVES: The primary goal of periodontal treatment is the maintenance of the natural dentition in health and comfortable function. The shift in therapeutic concepts from resection to regeneration has significantly impacted the practice of periodontology. The objective of the present study is to compare the relative efficacy of intra-oral autogenous graft and decalcified allogenic bone matrix (DABM) in the treatment of periodontal intrabony defects.
MATERIALS AND METHODS: In the present study, 30 patients in the age group of 30-50 years with two almost identical intrabony defects, on either side of the mouth/upper and lower jaw, based upon the radiographic observations were selected from amongst the patients visiting the Department of Periodontology and Oral Medicine, Punjab Government Dental College and Hospital, Amritsar. One of the defect was selected randomly and filled with autogenous cancellous graft and the other with DABM. Post-operative assessment was done by taking radiographs, 12 weeks and 24 weeks post-operatively.
RESULTS: Definite bone fill was achieved both with intra-oral free osseous autograft and with DABM at 12 weeks observation, which further increased significantly at 24 weeks observation. The bone fill obtained with intra-oral free osseous autograft was found to be significantly higher than that with DABM both at 12 weeks and 24 weeks post-operative observation.
CONCLUSION: Within the limitations of this study, it establishes the superiority of the intra-oral free osseous autograft over that of DABM graft in correcting the intrabony defects.

INTRODUCTION

The crux of the problem of chronic periodontal diseases lies in the changes that occur in the bone. Although, other tissues of the periodontium do get affected, yet it is the destruction of bone that is responsible for the loss of teeth. One objective of periodontal therapy is regeneration of the periodontal attachment including cementum, a functionally oriented periodontal ligament, and alveolar bone. Bone grafting is used as part of surgical protocols aimed at regeneration of periodontal structures. Autogenous bone grafts, bone derivatives like allografts, xenografts, and bone substitutes have been used for this purpose. Among the biomaterials, autogenous bone has been adopted as the gold standard because of:

Autograft bone includes cells participating in osteogenesis

A tissue reaction is induced without inducing immunological reactions

There is a minimal inflammatory reaction

There is rapid revascularization around the graft particles

A potential release of growth and differentiation factors sequestered within the grafts (Marx 1994).

In perspective, autograft bone has been considered to yield a high osteogenic potential and has thus been used with the intent to improve outcomes of periodontal regenerative procedures (Dragoo and Sullivan 1973, Hiatt and Schallhorn 1973, Renvert et al. 1985).

However, the use of autograft bone presents potential disadvantages such as a need for a wider or second surgery region; restricted donor sites make its use in cases with need for extensive grafting impractical. Moreover, and perhaps most importantly, the use of autograft bone has been reported to be attributed to result in tooth debilitating ankylosis and root resorption in human (Schallhorn and Hiatt 1972, Dragoo and Sullivan 1973) and dog intrabony defects (Levin 1975).[1]

Allogenic bone obtained from a different person and commonly processed by tissue banks provides an alternative to autogenous bone if the problems associated with the autogenous grafts are considered.[2] The initial use of demineralized allografts was based on compelling experimental data suggesting that it possesses osteoinductive potential. Decalcified allogenic bone matrix (DABM) has its own limitations regarding the availability of the grafting material, for which the operator has to depend upon a hospital source. Moreover, possibility of an immunological reaction and transmission of infective diseases are other disadvantages of DABM.[3] A major concern with allografts in general is the potential for disease transfer, particularly viral transmission, and, even more particularly, HIV. Treatment of cadaveric bone spiked with viral particles and cortical bone procured from a donor who had died of AIDS with a viricidal agent and demineralization in HCl has been found to inactivate HIV in both cases (Mellonig et al.).[4]

Both these materials have shown good results when tried individually,[5-8] but the literature is deficient in their comparative studies. In this study, therefore, an attempt has been made to evaluate and compare, radiographically, the relative efficacy of decalcified allogenic bone matrix and intra-oral free osseous autografts in the treatment of periodontal intrabony defects.

MATERIALS AND METHODS

Selection of patients

Thirty patients in the age group of 30-50 years were selected from amongst the patients visiting our department and were included in the study by taking written informed consent from each of them after explaining the study protocol.

The criteria for the selection of the patients were as follows:

Presence of two almost identical intrabony defects, on either side of the mouth/upper and lower jaw, based upon the radiographic observations. Only those patients were included who had an intrabony defect with a minimum of two walls, when viewed on surgical exposure. The other cases were excluded from the study

It was ensured that patients selected were not suffering from any systemic/debilitating disease

It was ensured that patients selected were not smokers

It was ensured that patients selected were not on any medication including antibiotics, corticosteroid, anti-hypertensive, immunosuppressant etc.

Grafting materials

Intra-oral free osseous autograft

This bone graft was obtained intra-orally from the patient's own mouth at the time of surgery from various sites viz., maxillary tuberosity region, edentulous regions of either maxilla or mandible, extraction sockets fresh or healed [Figure 1].

Figure 1

The trephine method for procurement of cancellous bone from the edentulous region

The bone was obtained after the reflection of the mucoperiosteal flap with the help of bur/chisel/bone rongeurs. The cortical bone was discarded, and the cancellous bone was utilized as the grafting material after being kept in sterile isotonic normal saline solution [Figure 2].

Figure 2

The procured autogenous cancellous bone

Decalcified allogenic bone matrix

The Decalcified allogenic bone matrix (DABM) used in our study was made from the fresh bone obtained from the corresponding dept of orthopedics, government medical college and hospital. The source of bone for preparing DABM was a government hospital recognized by the state government since decades. And, all the functioning of the hospital including biomedical waste disposal etc., was under the state health agencies recognized by the state government. The bone thus obtained was through proper channels with written records including patient's details like name, age, sex, medical status etc.

The following inclusionary/exclusionary criteria were followed while selecting the patients as donors:

The patient should be in good general/systemic health, except for the orthopedic problem, for which he has visited the hospital

The patient should not be on heavy doses of anti-microbials for any reason

After the initial pre-operative investigations performed by the orthopedic dept. including screening for HIV, HBV etc., the patient should be free of any type of systemic disease, for example any type of microbial infection, HIV, hepatitis etc

The bone thus obtained underwent a series of processes of demineralization and appropriate treatment with virucidal agents. The bone was sectioned into thin small pieces and then decalcified in 0.6 N Hcl, for 6 to 7 days till the bone became resilient. The bone so formed was repeatedly washed in normal saline solution, and the acid was removed by repeated washings with 70% ethanol. Decalcified allogenic bone matrix (DABM) so prepared was stored in 70% ethanol for 1-21 days before transplantation. On the day of the surgery, the graft material was first washed repeatedly in normal saline, and then boiled in distilled water for 30 minutes, and again kept in normal saline ready to be transplanted [Figure 3].

Figure 3

The procured DABM

According to Mellonig et al., 1992,[4] the use of exclusionary techniques in the procurement of bone allografts greatly reduced the chances of disease transmission. It was concluded by the authors that demineralization and the treatment with a virucidal agent inactivates HIV in spiked and infected bone.[4] According to Narang et al.,[9] the DABM grafts do not cause any immunologic response.

Routine investigations, prophylaxis, occlusal equilibration, and pre-operative intraoral peri-apical radiographs were taken using paralleling device, and the patients were instructed to adopt meticulous home care measures to control dental plaque.

Flap operations were carried out by a single operator each time to reduce the chances of biasing. The defects were randomly selected by the lottery method, and the intra-oral free osseous autograft (Site A) and DABM graft (Site D) were placed in the designated sites. We opted not to use GTR membranes to determine the sole role of the grafts used in producing radiographic bone fill and then have a comparison based truly on their individual abilities to form bone, as we know that GTR membranes in itself have the ability to form new bone if we provide enough space between the defect and the membrane.

The patients were given post-operative medications including:

Amoxicillin 500 mg + lactic acid bacillus 60×10[6] cells orally thrice-daily for 5 days post-operatively

A 60-second rinse with 15 ml of 0.2% chlorhexidine digluconate was prescribed twice-daily for 3 weeks

Ibuprofen 400 mg orally every 6-8 hours for 3 days and then as and when required by the patient was recommended for pain relief.

Plaque levels were periodically checked in both groups using plaque index, and oral prophylaxis was done at each follow-up visit (approx. every month).

RESULTS

Out of 30 patients, 29 patients reported, and all the statistical analysis was done for 29 patients. It was observed that both the materials were well tolerated by the patients as far as post-operative healing was concerned and did not show any allergic manifestation. According to Narang et al.,[9] the DABM's replacement with new bone was seen within 8 weeks, and the areas were completely free of any remnant of DABM graft at the end of 12 weeks. Similar is the situation with autogenous grafts. Therefore, we did the post-operative measurements at 12 weeks and 24 weeks post-operatively. Post-operative assessment was done by taking intra-oral peri-apical radiographs 12 weeks and 24 weeks post-operatively. The x-rays were standardized using a paralleling device specially designed for this purpose and the following fixed angulations (from vertical plane to occlusal plane) [Figure 4].

Figure 4

Paralleling device

Maxillary teeth

Molar teeth 30 degrees

Premolar 40

Canine 50

Mandibular teeth

Molar 0

Premolar -10

Canine -20

The mean bone fill was measured using an external metallic grid placed over the radiographic films. Then, the measurements were made using a vernier caliper in 1/10th of a millimeter [Figures 5 and 6].

Figure 5

Radiographic assessment of bone fill with intra-oral free osseous autograft using grid 4Ri- pre-operative, 4Rii- at 12 weeks, 4Riii- at 24 weeks

Figure 6

Radiographic assessment of bone fill with decalcified allogenic bone matrix using grid. 5Ri- pre-operative, 5Rii- at 12 weeks, 5Riii- at 24 weeks

The mean bone fill obtained for site ‘A’ and site ‘D’ after 12 weeks was 1.79 mm and 1.34 mm, respectively; while after 24 weeks, it was 2.89 mm and 1.85 mm, respectively [Figure 7 and Table 1].

Figure 7

Mean bone fill with two types of graft materials at various time intervals

Table 1

Comparison of mean change in bone fill at various time intervals between both graft materials

For statistical analysis, ‘unpaired-t test’ was applied. Statistical analysis showed that the difference between the two groups was non-significant; P>0.05 from baseline to 12 weeks, significant with P=0.004; P<0.01 (Significant at 1% significance level) from baseline to 24 weeks, and significant with P=0.005; P<0.01 (Significant at 1% significance level) from 12 to 24 weeks [Figure 8 and Table 2].

Figure 8

Standard deviations in bone fill at various time intervals within both sites

Table 2

Standard deviations in bone fill at various time intervals within both sites

DISCUSSION

The findings regarding the bone fill achieved with DABM are in conformity with the findings of Narang et al.,[10] Einhorn et al.,[11] Gill et al.[12] Turek[13] has reported that DABM itself gets resorbed and initiates host tissues to form new bone by its osteoinductive and osteoconductive property.

The findings regarding the bone fill obtained with intra-oral free osseous autograft are in conformity with the findings of Marvin,[14] Sindet-Pederson S,[15] Oosterbeek et al.[7]

When the relative efficacy of intra-oral free osseous autograft and the DABM was tested, the bone fill for autograft was found to be highly significant as compared to the bone fill for DABM, both after 12 weeks and 24 weeks. The higher bone fill achieved with autograft as compared to DABM may be attributed to the fact that the graft material consisted of viable osteoblasts and was osteogenic. Such material possesses the potential for bone formation at the grafted site.

The difference of the bone fill achieved with both the grafts at 24 weeks post-operatively was much higher than at 12 weeks post-operatively meaning, thereby, that with the passage of time from 12 weeks to 24 weeks, the gain in the bone fill achieved with the autograft is much higher than that of DABM graft.

CONCLUSION

Given the limitations in this study, the result obtained establishes the superiority of the intra-oral free osseous autograft over that of DABM graft in correcting the intrabony defects.

No doubt, an additional surgical site has to be created for the procurement of intra-oral free osseous autografts, yet, both the donor as well as the recipient site healed over the same period of time and showed no unusual finding as far as post-operative healing was concerned.