|Year : 2016 | Volume
| Issue : 4 | Page : 423-428
Comparative evaluation of the efficacy of synthetic nanocrystalline hydroxyapatite bone graft (Ostim®) and synthetic microcrystalline hydroxyapatite bone graft (Osteogen®) in the treatment of human periodontal intrabony defects: A clinical and denta scan study
Monika Kamboj, Ruchika Arora, Harinder Gupta
Department of Periodontology, Government Dental College and Hospital, Amritsar, Punjab, India
|Date of Submission||30-Dec-2014|
|Date of Acceptance||12-Apr-2016|
|Date of Web Publication||14-Feb-2017|
1202-C, Government Medical College and Hospital Campus, Sector 32b, Chandigarh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: To evaluate the relative efficacy of synthetic nanocrystalline hydroxyapatite (HA) (Ostim®) and microcrystalline HA (Osteogen®) bone grafts in the treatment of human periodontal intrabony defects clinically and radiographically through denta scan. Materials and Methods: Ten chronic periodontitis patients with bilateral intrabony periodontal defects of ≥2 mm radiographic defect depth below 55 years of age were selected randomly and treated with synthetic nanocrystalline HA (Ostim®) or synthetic microcrystalline HA (Osteogen®) bone graft. Clinical parameters including probing depth (PD) and clinical attachment level (CAL) were measured preoperatively and postoperatively at 3 and 6 months for each of the defects using an occlusal acrylic stent. Radiographic parameters were measured with the help of denta scan preoperatively and postoperatively at 6 months. Results: At 6 months following therapy, the Osteogen® group showed a reduction in mean PD from 11.10 ± 1.663 to 8.50 ± 0.850 mm and a change in mean CAL from 6.30 ± 1.160 to 3.40 ± 0.516 mm, whereas in the Ostim® group, the mean PD decreased from 11.20 ± 0.919 to 8.30 ± 0.823 mm and mean CAL decreased from 6.10 ± 0.738 to 3.30 ± 0.483 mm. At 6 months following therapy, denta scan showed a reduction in mean intrabony defect depth in the Osteogen® group from 2.54 ± 0.786 to 1.01 ± 0.448 mm, whereas in the Ostim® group, it was 2.71 ± 0.650 mm to 1.12 ± 0.563 mm. Conclusion: It was concluded that both the HA bone grafts produced statistically significant reduction in pocket depth, in the depth of osseous lesion, and a statistically significant gain in attachment level, irrespective of their physico-chemical properties.
Keywords: Denta scan, intrabony defects, microcrystalline hydroxyapatite, nanocrystalline hydroxyapatite
|How to cite this article:|
Kamboj M, Arora R, Gupta H. Comparative evaluation of the efficacy of synthetic nanocrystalline hydroxyapatite bone graft (Ostim®) and synthetic microcrystalline hydroxyapatite bone graft (Osteogen®) in the treatment of human periodontal intrabony defects: A clinical and denta scan study. J Indian Soc Periodontol 2016;20:423-8
|How to cite this URL:|
Kamboj M, Arora R, Gupta H. Comparative evaluation of the efficacy of synthetic nanocrystalline hydroxyapatite bone graft (Ostim®) and synthetic microcrystalline hydroxyapatite bone graft (Osteogen®) in the treatment of human periodontal intrabony defects: A clinical and denta scan study. J Indian Soc Periodontol [serial online] 2016 [cited 2017 May 28];20:423-8. Available from: http://www.jisponline.com/text.asp?2016/20/4/423/184036
| Introduction|| |
Hydroxyapatite [Ca10(PO4)6(OH)2] has been investigated as a bone replacement material for over 30 years and has a similar crystal structure to that of bone mineral. Synthetic hydroxyapatites (HAs) have been marketed in a variety of forms, primarily as a porous nonresorbable, a dense or solid nonresorbable, and a resorbable (nonceramic, porous) form.
Osteogen ®, a synthetic microcrystalline HA, is a nonsintered resorbable, particulate material processed at a low temperature with particles measuring 300–400 µm. Its reported advantage is the slow resorption rate, allowing it to act as a mineral reservoir at the same time acting as a scaffold for bone replacement.
Controlled clinical studies reported favorable clinical results following the surgical treatment of periodontal intrabony defects with HA materials compared to conventional open flap debridement alone. However, histologic studies revealed that healing often occurred with encapsulation of HA graft materials in connective tissue with minimal or no bone formation, and that the healing was characterized primarily by formation of a long junctional epithelium.
Recently, fully synthetic nanocrystalline HA bone graft (Ostim ®) containing about 65% water and 35% nanostructured HA particles has been introduced for augmentation procedures in osseous defect. Advantages of such a nanostructured material in comparison to conventional material are its close contact with surrounding tissues, quick resorption characteristics, and a higher number of molecules on its surface. It was found that undisturbed osseous integration and complete resorption of nanocrystalline HA paste occur within 12 weeks.
A recent study by Fathi et al. evaluated the bioactivity of microcrystalline and nanocrystalline HA in vitro and concluded that nanocrystalline HA crystals being more similar to biological apatite of bone, could be more useful for the treatment of oral bone defects in comparison to conventional HA and could be more effective as a bone replacement material to promote bone formation.
Hence the aim of the present study is to clinically evaluate the relative efficacy of synthetic nanocrystalline HA bone graft (Ostim ®) and synthetic microcrystalline HA bone graft (Osteogen ®) in the treatment of human periodontal intrabony defects.
For radiographic evaluation of the bone loss, three-dimensional image analysis using computed tomography (CT) and denta scan, first developed by Schwarz et al., in 1987, has been used in the present study. Denta scan, unlike routine dental X-rays, is distortion-free and illustrates the actual make-up of the bone. It enables the dental surgeon to visualize the bony structures preoperatively so that the surgeon does not have to make decisions intraoperatively making it a valuable tool for preoperative planning of the patients.
| Materials and Methods|| |
Ten systemically healthy patients below 55 years of age showing evidence of almost identical bilateral two- and three-walled intrabony defects measuring ≥2 mm with probing pocket depth of ≥5 mm requiring bone grafting procedures were selected from among those reporting in the outpatient department of periodontology, Punjab Government Dental College and Hospital, Amritsar. The subjects were selected randomly with no discrimination of sex, caste, religion, or socioeconomic status. A complete dental and medical history was obtained and a thorough clinical and denta scan examination was performed.
The following clinical parameters were evaluated preoperatively:
- Probing pocket depth
- Attachment level change (to ascertain the changes in the level of clinical attachment).
Denta scan with CT was taken preoperatively to ascertain the depth of the intrabony defect [Figure 1]. The defect was measured from a fixed reference point (cemento-enamel junction of the involved tooth) to the most apical point of the base of the intrabony defect. Alveolar crestal height was also measured from a fixed reference point (cemento-enamel junction of the uninvolved tooth) to the crest of the alveolar bone of the same tooth. The depth of the intrabony defect was then calculated by subtracting the alveolar crestal height from the total defect measured (CD − AB) [Figure 2].
|Figure 1: Preoperative denta scan showing intrabony defect mesial to first molar in patient A|
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|Figure 2: A and B denote alveolar crestal height from cemento-enamel junction of adjacent tooth and C and D denote the depth of defect from cemento-enamel junction of the tooth involved|
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After an explanation of the proposed study criteria, including treatment, the potential risks and benefits, the participants were asked to sign a consent form prior to the periodontal surgery. A Kirkland periodontal flap  was reflected and the operated area was debrided so that the intrabony defects were clear and prepared prior to the placement of graft and designated as Groups A and B. The synthetic nanocrystalline HA bone graft (Ostim ®) was placed in defects designated as Group A [Figure 3] and the synthetic microcrystalline HA bone graft (Osteogen ®) [Figure 4] was placed in defects designated as Group B. Flaps were repositioned and approximated by pressing with moist cotton, placed on both labial/buccal and lingual/palatal sides for 5 min. This was followed by interrupted interdental sutures given with 3-0 black-braided silk.
|Figure 3: Intraoperative photograph showing placement of Ostim® bone graft in the intrabony defect|
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|Figure 4: Intraoperative photograph showing placement of Osteogen® bone graft in the intrabony defect|
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Sutures were removed 1 week after surgery. The patients were recalled at monthly intervals for oral hygiene assessment by disclosing the presence/absence of tooth accumulated materials and to carry out scaling. Postoperatively, clinical parameters were recorded at 12 and 24 weeks whereas radiographic parameters were recorded at 24 weeks only [Figure 5].
|Figure 5: Postoperative denta scan showing bone fill mesial to first molar in the patient A|
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The observations thus recorded were put to statistical analysis. When, the data were subjected to the test of normality (Kolmogorov–Smirnov test), it was found that the data were not normally distributed. Hence, nonparametric tests, namely Wilcoxon signed-rank test and Mann–Whitney test for intra- and inter-group comparisons, respectively, were carried out.
| Results|| |
All the subjects completed 24-week follow-up. Follow-up assessment for clinical parameters was done at 12 and 24 weeks postoperatively, whereas for radiographic assessment by denta scan, it was done at 24 weeks only. The observations thus recorded were put to statistical analysis.
[Table 1] shows intragroup comparison of mean change in reduction in pocket probing depth (PD). The intergroup comparison of mean change in pocket PD between Group A (Ostim ®) and Group B (Osteogen ®) from baseline to 12 weeks was 0.100 mm, from baseline to 24 weeks was 0.300 mm, and from 12 to 24 weeks was 0.400 mm, all these values being statistically not significant.
|Table 1: Mean change in reduction in probing depth at various intervals within both groups (in mm)|
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[Table 2] shows intragroup comparison of gain in clinical attachment level (CAL). The intergroup comparison of mean gain in CAL between Group A (Ostim ®) and Group B (Osteogen ®) from baseline to 12 weeks was 0.100 mm and from baseline to 24 weeks was 0.100 mm, all these values being statistically not significant. There was no difference between the two groups from 12 to 24 weeks.
|Table 2: Gain in clinical attachment level at various intervals in both groups (in mm)|
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[Table 3] shows intragroup comparison of mean reduction in intrabony defect depth as shown in the denta scan. The intergroup comparison of reduction in intrabony defect depth between Group A (Ostim ®) and Group B (Osteogen ®) from baseline to 24 weeks was 0.700 mm, which is statistically not significant. The mean difference in linear bone fill of the intrabony defects between Groups A and B from baseline to 24 weeks was 0.120 mm, which is also statistically not significant.
|Table 3: Reduction in intrabony defect depth from baseline to 24 weeks postoperatively in both groups (in mm)|
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| Discussion|| |
For over two decades, regenerative therapy has been finding its way into the disciplines of periodontology and implantology. Currently, bone replacement grafts, including autografts, allografts, xenografts, and alloplasts are the most widely used treatment for the regeneration of periodontal-supporting tissues lost as a consequence of periodontitis. Various studies by Aichelmann-Reidy and Yukna, 1998; Froum et al., 1982; Nasr et al., 1999 have shown that although open debridement flap procedures alone without the use of bone grafts have shown to yield 10–30% osseous fill in periodontal defects, a mean defect fill of 60–70% can be anticipated with bone replacement grafts.
HA is one of the most widely used alloplastic grafts in both the research and clinical fields. It has a similar composition and structure to natural bone mineral and is known to chemically bond directly to bone when implanted. The properties of HA ceramics can be improved by controlling important parameters of powder precursors such as particle size, particle distribution, and agglomeration.
In the present study, synthetic microcrystalline HA Osteogen ® which has shown promising results as regenerative material (Osteogen ® Product Catalog) along with recently developed synthetic nanocrystalline HA (Ostim ®) with its improved handling properties, better osteoconduction, and the ability to promote periodontal ligament cell proliferation  was used and compared clinically and radiographically by denta scan over a period of 6 months.
Comparison of probing depth
Pocket shrinkage following periodontal therapy occurs through a combination of tissue responses. Sufficient shrinkage may occur with resolution of the edema and inflammation along with remodeling of the connective tissue following removal of the irritants. Further changes in the tissue occur through new attachment by a long junctional epithelium coronally and/or re-adaptation of the gingival connective tissue to the root surface apically.,
Statistically significant reduction in probing pocket depths at 6 months following treatment of intrabony periodontal defects with nanocrystalline HA paste (Ostim ®) has been reported by Kasaj et al.; Heinz et al. (2010); and Priyadarshini et al. Similar findings in Group B can be attributed to the mineral reservoir concept of Osteogen,® which suggests that resorption and maturation of the graft are continuous over the period of 6 months that can lead to continued improvements in the clinical parameters with time.
Comparison of clinical attachment level
Most bone replacement grafts are osteoconductive, osteointegrative, and relatively inert-filling materials. Osteoconductive materials provide a scaffold to allow bone ingrowth and deposition and may support significant improvements in clinical PDs and attachment levels. Furthermore, studies have shown that bone grafts prevent apical proliferation of junctional epithelium, thereby leading to actual gains in CAL postoperatively.,
The results in the present study are in accordance with those of Kasaj et al. and Chitsazi et al., who reported similar statistically significant gain in CAL at 6 months following treatment of intrabony periodontal defects with Ostim ®. In addition, a study by Corsair  has shown that Osteogen ® retards epithelial migration apically resulting in gain in CALs postoperatively at 6 months.
Intergroup comparison of clinical parameters
On comparative evaluation of the two groups, the difference in mean reduction in pocket PD as well as mean gain in CAL at various time intervals was found to be statistically not significant.
The improvement in the clinical parameters in the present study was in concurrence with the findings of Yukna et al. and Galgut et al., which exhibited a tendency for greater healing postoperatively in absolute terms in deeper pockets than in shallow pockets regardless of the treatment procedure performed. In addition, for the initially moderate and deep pockets, the implanted sites tended to continue to maintain the improvement in clinical parameters compared to baseline as the follow-up progressed. This was proved by the fact that in both the groups, clinical parameters exhibited small but statistically significant improvements in the second half of the follow-up, i.e., from 12 to 24 weeks. However, maximum reduction in clinical parameters in both the groups occurred in the first 12 weeks following surgery after which a small albeit significant change was seen between 12 and 24 weeks postoperatively. This can be substantiated on the basis of the work done by Dragoo and Sullivan, who concluded that though dramatic changes occur in the tissues postoperatively after 3 months leading to improvements in clinical parameters, the trend toward maturity continued in the 4th and 6th months and even till 8 months, thereby resulting in sustained improvements in the parameters.
Comparison of radiographic parameters
Synthetic nanocrystalline HA bone graft - Ostim ® treated sites showed a significant linear bone fill as seen by the increased radio-opacity postoperatively as also observed by Heinz et al. (2010); Priyadarshini et al.; and Singh et al. This can be explained by the research work done by Webster et al. and Kasaj et al. that has shown a significant increase in protein absorption and osteoblast adhesion on the nano-sized ceramics, thereby increasing the binding of nanocrystalline HA bone graft to the bone and stimulating bone healing. In addition, Pezzatini et al. in their in vitro study concluded that nanocrystalline HA is a strong promoter of angiogenesis, while Kasaj et al. have also shown that nanocrystalline HA is a stimulator of periodontal ligament cells, thereby contributing to periodontal tissue regeneration.
Synthetic microcrystalline HA bone graft - Osteogen ® treated sites showed a significant linear bone fill as observed by the increased radio-opacity postoperatively as observed by Corsair  who found similar bone fill in their studies. This can be explained on the basis of the “mineral reservoir” hypothesis reported by Wagner, who described Osteogen ® as a highly micro-porous, nonsintered (nonceramic), bioactive bone grafting material with a mineral reservoir and predictably induces new bone formation via osteoconductive mechanisms. When placed in direct contact with bone, there is little if any intervening soft tissue. Further, the crystalline structure of the resorbable HA (Osteogen ®) enhances its chemical composition by serving as a scaffold upon which the body can build new bone as it slowly resorbs the material.
The present study showed mean defect fill of 59.8% in Group A and 61.2% in Group B, the difference being statistically not significant. Various studies have concluded a literature-based estimate of bone fill ranging from 2.3 to 3.0 mm or 60% of the defect following grafting of intrabony defects.
Moreover, the present study also observed residual defect depth in all the sites with no site exhibiting 100% bone fill postoperatively. The most coronal portion of the defect is considered to be the most susceptible portion to possible negative influences from the oral environment, which may negatively mediate healing responses. Thereby, even strictly three-walled bony defects have shown to have an incomplete fill at the coronal extent of the defect.
Thus, within the constraints of the present study, it can be concluded that both the HA bone grafts, though differing in their physico-chemical properties, produced clinically and radiographically comparable improvements in the treatment of intrabony periodontal defects.
However, it is important to emphasize that the data generated by this study are derived from a small sample size over a period of 6 months which is probably a short time interval when one considers the long-term success of regenerative procedures. Long-term studies are suggested to evaluate the sustainability of the results. In addition, to know the exact nature of the changes in the measured parameters, namely, reduction in PD, gain in clinical attachment, linear bone fill, and change in alveolar crestal height, a histological study over a longer time period is suggested.
| Conclusion|| |
It can be concluded from this study that both the hydroxyapatite bone grafts, Ostim ® as well as Osteogen ®, though, differing in their physicochemical properties, yet, produced clinically and radiographically comparable improvements in the treatment of intrabony periodontal defects. The present study also further substantiated the fact that, though, scaling and root planing is an important initial therapeutic procedure that halts the further progression of periodontal disease, yet, regenerative procedure utilizing various bone grafts is the indispensable part of treatment plan being the definitive therapeutic procedure that can correct the anatomical defects created by the disease process through new attachment and regeneration.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]