TITLE: 
Evaluation of hydroxyapatite (Periobone-G) as a bone graft material and calcium sulfate barrier (Capset) in treatment of interproximal vertical defects: A clinical and radiologic study



ABSTRACT.BACKGROUND:
This study has been undertaken to assess treatment response of interproximal vertical defects using an alloplast (Periobone-G) and calcium sulfate (Capset) as a barrier both clinically and radiographically.

ABSTRACT.MATERIALS AND METHODS:
Eight patients were selected with 16 sites that were divided into control and experimental sites based on split mouth study design. Plaque index, gingival index, probing depth, clinical attachment level, gingival margin position were recorded at baseline and 9 months and radiographic assessment was done at baseline and 9 months after recording clinical parameters, the sites were randomly treated either with hydroxyapatite granules Periobone-G or hydroxyapatite granules (control group) was used to fill the osseous defect and calcium sulfate (Capset) (experiment group) barrier was placed.

ABSTRACT.RESULT:
The plaque score reduction was statistically highly significant within control and experimental groups. The gingival score reduction was significant within control and experimental groups, although there were no significant difference between the 2 groups. The pocket depth reduction was significant within control and experimental group, however, the hydroxyapatite + capset group showed significant reduction as compared with hydroxyapatite alone group. The clinical attachment gain and gingival margin position was significant within control and experimental groups, although there was no significant difference between the 2 groups. The amount of defect fill was significant in both control and experimental groups but the difference between the 2 groups was not significant. The mean change in alveolar crest level between control and experimental groups was significant (P=0.02). The percentage of original defect resolved was not significant.

ABSTRACT.CONCLUSION:
The use of calcium sulfate as a barrier proved its role in the treatment of interproximal defects. The application of calcium sulfate (Capset) barrier is easy and simple. The multifaceted properties of calcium sulfate demonstrate its usefulness in periodontal practice.

BODY.INTRODUCTION:
Periodontal disease is one of the most prevalent afflictions worldwide. The most serious consequence is the loss of the periodontal support structure, which includes cementum, the periodontal ligament, and alveolar bone.[1] The regeneration of a periodontium destroyed by periodontal disease has been an elusive goal sought by all who treat periodontal problem. One of the biggest challenges in periodontics is the treatment of infrabony defects. Osseous defects can be treated with resective therapy but may result in significant tissue recession and unaesthetic appearance. However, regenerative treatment for osseous defects has the potential for replacing lost tissues and minimizes tissue recession. Moreover, the bone grafts appear to increase the chance of new attachment when compared with debridement alone.[2] Various reports on the filling in of bone defects after periodontal surgery suggest a considerable degree of bone fill and others have found residual bone defects after surgery.[3] The unpredictability of filling in of bone defects after periodontal surgery has resulted in the investigation of various types of bone graft materials and of synthetic implants materials.
Hydroxyapatite ceramics come very close to fulfilling the criteria for the ideal bone substitute. The most important feature of hydroxyapatite when compared with other inorganic materials is its unique biologic properties as it consists of only calcium and phosphate, which is found in the human organism and no toxicity or defence reaction is expected. The biocompatibility, tolerance, and biologically active property of hydroxyapatite make it an ideal bone substitutes. The porous hydroxyapatite is a pure uniquely resorbable hydroxyapatite (HA) implant material used for alloplastic augmentation and the repair of bone defects. The material used is chemically and crystallographically equivalent to the mineral portion of human bone, specifically hydroxyapatite [Ca10 (PO4)6 OH2]. The material was available under the product name of “PERIOBONE-G” marked by Top-Notch Health Care Product Pvt. Ltd., India.
Plaster of Paris (calcium sulfate) is one the most versatile materials used in dentistry. Calcium sulfate can function as resorbable space filler, a resorbable barrier a vehicle for control released chemotherapy and as a biocompatible, biodegradable compound a composite mixture with other bone grafts, better tissue healing, and rare post operative complication. All of these properties contribute to its usefulness in periodontal surgery.[4]
Dressman[5] first used calcium sulfate to fill bony defects. Bell[6] demonstrated resorption of calcium sulfate was 4.7 weeks in dogs. Najjar[7] shows that hydroxyapatite and calcium sulfate composite enhances bone formation within few weeks in animals. Sottosanti,[8] Anson,[9] Bier and Sinesky[4] observed that calcium sulfate can be effectively used as a resorbable barrier in human periodontal osseous defects. Orsini[10] reported no significant difference between pocket depth and clinical attachment level in those sites treated with autogenous graft alone and combination of autogenous graft with calcium sulfate (Capset) as a barrier over 6 months study period.
Capset (Lifecore Biomedical Inc., USA), calcium sulfate bone graft barrier is used to cover the underlying bone graft and to prevent it from displacement during postoperative healing and also it can be used as a composite graft material. Medline search using keywords such as interproximal defects, calcium sulfate, barriers, and periodontitis revealed minimal studies.
Hence, this study has been undertaken to assess treatment response of interproximal vertical defects using an alloplast (Periobone-G) and calcium sulfate (Capset) as a barrier both clinically and radiographically.

BODY.MATERIALS AND METHODS:
Rajiv Gandhi University of Health Science review committee approved protocol for human subjects. The study group included patients minimum of two interproximal sites having vertical defect. Total of 8 periodontitis patients (4 female and 4 male) age group between 26 and 58 years were selected. Total of 16 sites were divided into control and experimental sites based on split mouth study design. It is a randomized, double-blind clinical trial; the study period was 1.5 years.
BODY.INCLUSION CRITERIA:

(a)Periodontal pockets measuring probing depth of 5-7 mm with vertical bone loss radiographically
(b)Presence of at least 2 interproximal sites.



BODY.EXCLUSION CRITERIA:

(a)Patients showing unacceptable oral hygiene during presurgical therapy, without any history of systemic disease, or compromising medical condition.
(b)Pregnancy and lactating mothers
(c)Smokers.



BODY.BASELINE RECORDING OF CLINICAL PARAMETER:
After the informed consent was taken, the patients were included in the study and the following clinical parameters were recorded at the baseline:

Plaque index[11]
Gingival index[12]
Probing depth, clinical attachment level, gingival margin position measurement by using the customized acrylic occlusal stents with grooves, which were prepared on the study model of the patients.


The recordings were made using a Hu-Friedy PCP-UNC 15 probe. The single examiner recorded all the measurements was blinded. The clinician who performed the surgery held the randomization code.

BODY.RADIOGRAPHIC PARAMETERS:
The intraoral periapical radiograph of each site was taken by using the long cone paralleling technique and then interpretation was done with intraoral periapical radiograph of each site was digitized using a flat bed scanner with a scanning resolution of 600 dpi (UMAX-ASTRA 1220S). The scanned images, stored in JPEG format were transferred to COREL DRAW 7. For measurement, connector line tool was used. The cementoenamel junction (CEJ), the base of the defect, and the crest of alveolar bone were located on the image. Using the connector line tool, a line is drawn from CEJ to base of the defect. The length of the line was displayed in the size property box of the software. The software then displays the distance between these 2 points. The same procedure was then repeated to obtain the distance between CEJ and alveolar crest. Subtracting the 2 measurements the depth of the osseous defect was obtained. By using the above method for pre-and postsurgical radiographs, the radiographic measurements were obtained for each site. Clinical and radiographic evaluation was done at baseline, 3, 6, and 9 months.

BODY.SURGICAL PROCEDURE:
All the selected patients were subjected to Phase-1 therapy 4 weeks prior to surgery.
Patient was seated comfortably on the dental chair and then asked to rinse the mouth with 10 mL of 0.2% chlorhexidine digluconate solution. The extraoral surfaces of the patient were swabbed with 5% povidone iodine solution. The operative site was anesthetized with 2% xylocaine HCl with adrenaline (1:80000), using block and infiltration techniques. The crevicular incisions were given on the facial and lingual sides using the bard parker handle no. 3. A full-thickness mucoperiosteal flap was reflected using the periosteal elevator, taking care that the interdental papillary tissue was retained as far as possible. After reflection of the flap and exposure of osseous defect, thorough surgical debridement of both soft and hard tissues was done using curettes and scissors. After completion of root planning, the surgical site was irrigated with 0.9% normal saline, and then root surfaces were conditioned with tetracycline hydrochloride solution [Figures 1–3].
Figure 1Site showing debridement
Figure 2Interproximal defect with UNC-15 Probe
Figure 3Tetracycline root conditioning
In the control site, the defects were filled with hydroxyapatite granules (Periobone-G), the required quantity of hydroxyapatite granules was transferred to the dappen dish and moistened with sterile saline, which was then placed into the vertical defect with the help of scoop of cumine scaler (Hu-Friedy), to the approximate level of the crest of the remaining osseous walls.
In the experimental site, hydroxyapatite granules were used to fill the osseous defect and calcium sulfate (Capset) barrier was placed. After the defect was filled with hydroxyapatite granules following the same procedure as for control site, the barrier was placed. The barrier was prepared by mixing the barrier in a dappen dish for approximately 30 s. The barrier was then applied with wax spatula. Dry gauze was placed over the barrier and wax spatula was used to condense the barrier. The barrier should approximately overlap 3-4 mm of the defect margins and was about 1.5-2 mm thick [Figures 4 and 5].
Figure 4Defect filled with hydroxyapatite granules
Figure 5Placement of calcium sulfate barrier over defect filled with hydroxyapatite granules
The mucoperiosteal flaps were repositioned and secured in place by tightening the presuture done using a 3/8 circle, reverse-cutting swaged needle and 3-0 black-braided silk suture. Interrupted sutures were placed to obtain primary closure of the interdental papilla [Figure 6] and the area was protected with a noneugenol dressing (Voco-Pac). The antibiotics (amoxicillin 500 mg tid for 5 days) and analgesics (diclofenanc 50 mg bid for 5 days) were prescribed; oral hygiene instructions were given; the patient was recalled after 10 days for the suture removal; and the surgical site was irrigated with normal saline. Recall appointments of the patients were made after 3, 6, and 9 months. Finally at the end of 9 months, all the clinical and radiographic parameters were repeated for both the control and experimental sites and the values were statistically analyzed.
Figure 6Sutures

BODY.RADIOGRAPHIC MEASUREMENT:
Intraoral periapical (IOPA) radiographs were taken for each site before surgical procedure and at intervals of 9 months postsurgery using long cone paralleling technique [Figures 7–10].
Figure 7Baseline control site
Figure 8Nine months postsurgery
Figure 9Baseline experimental site
Figure 10Nine months postsurgery
Q—Distance from CEJ to the Base of the defect of Experimental site (Baseline)
R—Distance from CEJ to the alveolar crest of the defect of Experimental site (Baseline)
q—Distance from CEJ to the Base of the defect of control site (Baseline)
r—Distance from CEJ to the alveolar crest of the defect at control site (Baseline)
Q9—Distance from CEJ to the Base of the defect of Experimental site (Postsurgically)
R9—Distance from CEJ to the alveolar crest of the defect at Experimental site (Postsurgically)
q9—Distance from CEJ to the Base of the defect at control site (Postsurgically)
r9—Distance from CEJ to the alveolar crest of the defect at control site (Postsurgically).

BODY.ARITHMETIC DETERMINATION:
Baseline defect depth (Q – R) = Baseline CEJ to the base of the defect - baseline CEJ to the alveolar crest.
Postsurgical depth-Q9-R9= Postsurgically CEJ to base of the defect - postsurgical CEJ to the alveolar crest.
Amount of defect fill (mm) = initial defect depth - postsurgical defect depth.
% Defect fill = amount of the defect fill × 100/baseline defect depth
Change in alveolar crest (R – R9) = change in alveolar crest at baseline – change in alveolar crest postsurgically.
% Change in alveolar crest = change in alveolar crest × 100/baseline defect depth.
% Original defect resolved = [(Q-R) – (Q9-R9)]-(R-R9) × 100/base line defect depth = % of defect fill – % of change in alveolar crest.
The results were subjected to statistical analysis.
Posttreatment changes in the probing depth and other clinical parameters in both experimental and control groups were analyzed by paired t test within a group (intergroup); and intergroup comparisons were done by unpaired t test. Intergroup comparison of changes in both clinical and radiologic parameters were analyzed by Mann-Whitney U test.


BODY.RESULTS:
This study evaluated the effectiveness of porous hydroxyapatite (Periobone-G) with and without the application of calcium sulfate barrier (Capset) in the treatment of interproximal vertical defects. All the selected sites, the following clinical parameters were assessed at baseline, 3, 6, 9 months postsurgery. For statistical analysis, the comparison was considered from baseline to 9 months.
Clinical parameters included were plaque index, gingival index, pocket depth, clinical attachments level, and gingival margin position. Radiographic parameters included were amount of defect fill, percentage of fill of original defect, change in alveolar crest, and percentage of original defect resolved.
On comparison between control and experimental groups, the plaque and gingival index score reduction was statistically highly significant within control and experimental groups, although there was no significant difference between the groups [Figure 11]. At control sites, the mean pocket depth at baseline was 6.13±0.64 whereas after 9 months postsurgery was 4.88±0.35. The mean pocket depth reduction was 1.25±0.46 (20.4%) at 9 months postsurgery, which was highly significant (P<0.001). In experimental group, the mean pocket depth at baseline was 7.63±1.69, whereas after 9 months postsurgery, it was 4.13±1.36. The mean pocket depth reduction was 3.50±1.41 (45.9%) at 9 months postsurgery, which was highly significant (P<0.001). The mean pocket depth reduction was significant at 9 months postsurgery (P=0.01). In control group, the mean attachment level at baseline was 6.13±0.83, whereas the value after 9 months postsurgery was 4.38±0.52. The mean attachment gain when compared from baseline to 9 months postsurgery was 1.75±0.46 (15.1%) at 9 months postsurgery, which was highly significant (P<0.001). The mean attachment level in experimental group at baseline was 7.13±1.46 whereas value at 9 months postsurgery was 4.38±1.30. The attachment gain when compared from baseline to 9 months postsurgery was 2.75±1.28 (38.6%), which was highly significant (P<0.001). The mean gain when compared between control and experimental groups at 9 months postsurgery was not significant (P=0.18).
Figure 11Plaque index and gingival index
In control group, the mean gingival margin position at baseline was 5.00±0.00 and at 9 months postsurgery was 5.50±0.53. The gingival margin when compared from baseline to 9 months postsurgery was – 0.50±0.53 (10%), which was significant (P=0.03). In experimental group the mean gingival margin position at baseline was 5.13±1.46 and at 9 months postsurgery was 5.88±1.55. The gingival margin when compared from baseline to 9 months postsurgery was – 0.75±0.71 (14.6%), which was highly significant (P<0.001). The mean change in gingival margin position when compared between control and experimental groups the value at 9 months postsurgery was not significant (P=0.52) [Figure 12].
Figure 12Pocket depth, clinical attachment level and gingival margin position
BODY.RADIOGRAPHIC PARAMETER:
In control group, the mean baseline defect depth was 5.89±2.25, whereas mean amount of defect fill after 9 months postsurgery was 2.70±2.77. The mean difference from baseline to 9 months was significant (P<0.01). In experimental group, the mean baseline defect depth was 6.43±0.81, whereas mean amount of defect fill after 9 months postsurgery was 2.19±1.17. The mean difference from baseline to 9 months was significant (P<0.001). The mean of original defect fill when compared between control and experimental groups to 9 months postsurgery was not significant (P<0.96).
In control group, the mean percentage of original defect fill at 9 months postsurgery was 32.7±48.0 in experimental group the mean percentage of original defect fill at 9 months postsurgery was 33.8±17.1. The mean percentage fill of original defect when compared between control and experimental at 9 months postsurgery was not significant (P=0.63).
The mean percentage of original defect resolved in control and experimental groups after 9 months postsurgery was 21.1±84.5 and 29.0±53.8. The mean percentage of original defect resolved when compared between control and experimental groups 9 months postsurgery was not significant (P=0.19) [Figure 13].
Figure 13Percentage fill of original defect and percentage of original defect resolved


BODY.DISCUSSION:
The reconstruction of lost alveolar bone support has long been a challenge in periodontics. Loss of alveolar bone support is one of the characteristic signs of destructive periodontal disease. But now due to the expansion of horizons in the field of treatment modalities, the present goal of periodontal therapy is not only focused at eliminating infection form the diseased sites but also aimed at restoring the tissues lost, to the original level.[13]
In the previous decades, number of new materials has been used in the treatment of periodontal osseous defects, which includes various types of GTR membranes and variety of bone graft material. Many types of bone grafts have been used with varying degrees of success, including autografts, allograft, xenograft, and alloplastic materials. Alloplastic materials are the bone substitutes, such as calcium sulfate, calcium phosphate, bioactive glasses, which are biocompatible with host tissues, resorbable in appropriate time, and scaffold for ingrowth of tissue cells to lay down tissue matrix. Because of these reasons bone substitutes have been used since 100 years.
Periobone-G (hydroxyapatite) developed as a bone implant material has long been the subject of extensive investigation. This material chemically and crystallographically equivalent to the mineral portion of human bone, specifically hydroxyapatite [Ca10(PO4)6OH2]. The material is devoid of local or systemic toxicity, does not elicit inflammatory or foreign body responses, can become functionally integrated with natural bone, and causes no alteration of normal bone mineralization process.
Capset is calcium sulfate bone graft barrier used to cover the underlying bone graft and protect it from displacement during postoperative healing.
By considering the above properties of Periobone-G and Capset, this present clinical study was conducted. In this, 8 control sites was grafted with hydroxyapatite granules (Periobone-G) and experimental site was grafted with hydroxyapatite granules (Periobone-G) over which calcium sulfate barrier (CAPSET) was placed in another 8 sites. In this study, no negative control was used. Kenney et al.[14] reported that debridement when compared with either bone graft/membrane alone, the latter group showed improved attachment level and bone fill. Clinical parameters consisted of evaluation of plaque index, gingival index, pocket depth, clinical attachment level, gingival margin position, and radiographic measurements at baseline and 9 months postsurgery. There was no allergic reaction to the material in any of the patient during the study period. The tolerance of the material form a clinical stand point was excellent.[10]
There was a significant reduction in plaque index score from baseline to 9 months postsurgery in both experimental and control groups. When compared between experimental and control groups there was no significant difference. This was similar to the study by Oreamuno et al.[15] who used porous hydroxyapatite and Decalcified Freeze Dried Bone Allograft in treatment of periodontal intrabony defects and observed significant reduction in plaque index score and intergroup results were not significant.
There was a significant reduction in gingival index score from baseline to 9 months postsurgery in both experimental and control groups. When compared between experimental and control groups it was significant (P=0.02).
Within experimental and control groups, there was significant pocket depth reduction from baseline to 9 months similar to the study of Kenney et al.[14] and Orsini et al.[10] Kenney et al.[14] used porous hydroxyapatite in the treatment of intrabony defect and observed the significant reduction in pocket depth from baseline to 6 months. Orsini et al.[10] reported significant pocket depth reduction at those sites treated with autogenous bone graft and Capset as a barrier. When compared between experimental and control groups in the present study there was significant pocket reduction (P<0.01) in contrast to the finding of Orsini et al.,[10] who compared autogenous graft alone in the control site and autogenous graft and Capset barrier in the experimental site reported no significant reduction in pocket depth from baseline to 6 months between the groups.
There was significant gain in clinical attachment level from baseline to 9 months postoperatively in both experimental and control groups. When compared between experimental and control groups, there was statistically no significant difference, similar to the study of Orsini et al.[10]
There was a significant change in gingival margin level from baseline to 9 months postoperatively within the experimental group and there was no significant difference between control and experimental groups.
BODY.RADIOGRAPHIC ASSESSMENT:
The clinical variables are the indirect measures of the amount of regeneration occurring at sites. The primary outcome variable can be measurement of new bone formation. Direct measurements, including linear and volumetric assessments are by far best tools. However, the need for second surgical procedure is a definite drawback of this technique. To overcome the difficulties, indirect methods of alveolar bone measurement have been utilized with various degree of success. Radiographic bone measurements following regenerative procedures is a noninvasive, painless alternative to direct bone measurements. Conventional radiography offers simplest and most cost-effective radiographic method but has limited sensitivity and potential geometric distortion. One approach designed to avoid there potential error is taking standardized radiographs to establish reproducible source tooth film geometry. Image processing technique16] Measurement of the periodontal defects from a fixed reference point to the base of the alveolar defect has some value for monitoring osseous changes following regenerative treatment.[17] The radiographic techniques used in the study include longcone/paralleling technique in combination with digital processing of the images to measure bony changes.
In the current study, defect fill was evident in both control and experimental sites. The mean defect fill when compared between control and experimental groups at 9 months postsurgery was not significant (P=0.96). In the present study, the percentage of original defect fill in the experimental group at 9 months was 33.8±17.1 and control site was 32.7±48.0. The comparison between control and experimental sites at 9 months postsurgery was not significant (P=0.63).
In the present study, the change in alveolar crest was similar to Meffert et al.[18] who observed significant change in alveolar crest height in those sites treated with porous hydroxyapatite. In the present study, the mean change in alveolar crest level when compared between control and experimental groups postsurgery was significant (P=0.02).
The mean percentage of original defect resolved after 9 months was 21.1±84.5 at control sites, at experimental site was 29.0±53.8. The difference between the groups was not significant (P=0.19).
The studies related to Capset as a barrier material/bone graft are scanty, which discuss mainly the clinical parameters. Hence, there are no studies to compare radiographic assessment of this study.
From this study, the rationale for using medical grade calcium sulfate for a barrier is that

It is biocompatible and causes no increase in inflammation
It resorbs completely in 3-4 weeks
It causes no additional discomfort.


The added advantages of calcium sulfate barrier are as follows:[19]

It adheres to surface contours, even if deep grooves are present
Its porosity allows for fluid exchange so that flap necrosis is not a problem
It is dense enough to exclude connective tissue and epithelium
In the early stages of healing it protects the clot.




BODY.CONCLUSIONS:
The Capset barrier along with hydroxyapatite and hydroxyapatite alone produced similar periodontal parameter improvement. The use of calcium sulfate as a barrier proved its role in the treatment of interproximal defects. The application of calcium sulfate (Capset) barrier is easy and simple. The multifaceted properties of calcium sulfate demonstrate its usefulness in periodontal practice. The ease of availability and cost of calcium sulfate scores better over other GTR barrier in day-to-day periodontal surgical work. However, Capset is expensive and not available in India.
Furthermore, studies should be directed using Capset as a composite bone graft material in various osseous defects.

Question: Compared to hydroxyapatite granules (control group) what was the result of hydroxyapatite granules Periobone-G on The mean change in alveolar crest level?
Evidence:  The mean change in alveolar crest level between control and experimental groups was significant (P=0.02)
Answer: significantly increased