Evaluation of SilOss® in Periodontal Surgery
Condition: Chronic Periodontitis
MeSH terms: Periodontitis; Chronic Periodontitis
Study type: Interventional
Phase: Phase 2

Summary: 
      Siloss® (Azurebio, Madrid, Spain) is a synthetic and inorganic bone graft material and is
      composed of a dicalcium phosphate anhydrous (monetite), hydroxyapatite (HA), and amorphous
      silica and trace amounts of zinc. It is manufactured by a proprietary process avoiding high
      temperatures. This results in a non-sintered material with a high specific surface area (65
      m2/g) and high interconnected porosity (60%) that favour a high degree of interaction with
      its biological surrounding. It is fully resorbable, being replaced by natural bone, thereby
      avoiding the disadvantages of nonresorbable materials that interfere with normal processes of
      bone remodelling. Siloss® is resorbed both by a dual process of slow dissolution of its
      components and by active cellular remodelling. Controlled dissolution of Siloss® releases Ca,
      P, Si and Zn that stimulate regeneration processes while larger pores are formed allowing
      colonization of osteoclasts and osteoblasts involved in bone remodelling. It functions as a
      bioactive temporary scaffold maintaining the desired volume while it promotes bone
      regeneration and is being replaced by new vascularized bone. The alloplastic property of the
      graft material avoids the risk of infection and adverse inflammatory reactions. Also,
      resorption of Siloss® prevents possible adverse effects associated with long permanence of
      low resorbable materials.

      The aim of the present study is to clinically and radiographically evaluate the efficacy of
      bone graft material (Siloss ®) in the treatment of intrabony defects.
    

Detailed description: 
      Study design The study was designed as a split-mouth, double-blind, randomized controlled
      clinical trial. The purpose of this study is to evaluate the efficacy of a novel synthetic
      bone regeneration material (Siloss®) in the treatment of periodontal intrabony osseous
      defects. Ethical clearance has been obtained from the institutional ethical committee with
      participants signing an informed consent prior to the commencement of the study.

      Sample Size calculation Sample size was calculated by considering this trial as a
      non-inferiority trial. A minimum sample size of 27 will be required when the minimum
      difference of mean bone fill levels before and after treatment is to be at least 1mm2 at
      p=0.05 with expected variance of 0.8 for having ß=0.1.

      Source of data A total of 30 subjects were selected from the outpatient section of the
      Department of Periodontics. Systemically healthy chronic periodontitis subjects within the
      age group of 30-55 years having at least 2 periodontal pockets ≥5 mm with at least 1 pocket
      in each quadrant showing ra¬diographic evidence of vertical bone loss were included in the
      study. Patients who underwent periodontal therapy in the past 6 months and/or have used
      antibiotic drugs, antioxidants, and antibacterial mouthwash or medicated toothpastes within 6
      months of baseline and smokers were excluded from the study. Assessment of suitability for
      bone graft was confirmed by transgingival probing to verify the presence of well-contained
      interdental bone defects in as many quadrants.

      Randomization and Blinding Randomization and blinding included computerized generation of the
      allocation sequence in random permuted blocks (block randomization) and blinded disbursement
      of medication. Allocation was performed by assigning the block of sites to study groups
      according to the specified sequence. Based on the sequence, the first operator selected two
      sites for each of the following experimental sites; the test site, in which graft (Siloss®)
      was placed and the control site which was treated by Hydroxyapatite graft only. All the
      surgeries were performed by a designated operator for the sake of uniformity whereas the
      relevant readings were recorded by the first operator who was blinded to the nature of the
      site. The blind was not broken until this clinical trial was completely finished.

      Standardization of PPD and CAL PPD and CAL were recorded at the baseline and at the end of 3,
      6 and 9 months using a UNC-15 color-coded periodontal probe. An alginate impression was taken
      and custom acrylic stent limited to the occlusal 2/3rds of the clinical crown were used as
      fixed reference position (i.e. junction of vertical groove and lower border of the stent). A
      groove was prepared in the stent to standardize the probing angulation throughout the study
      period.

      Standardization of radiographs Standard digital IOPA radiographs were taken at baseline, 3
      and 6 months by the paralleling/long-cone technique at preset parameters using a commercially
      available RVG (Radiovisiography) system (Kodak RVG 5100® Digital Radiography System,
      Carestream Health, Rochester, USA). After the imaging plate was placed in the film holder for
      paralleling technique (XCP Kits for Digital Sensors®, BlueDent, Chennai, India), addition
      silicon impression material (Elite HD+ Regular Body Normal Set®, Zhermack, Badia Polesine,
      Italy) was added around the biting surface and allowed to set. This arrangement ensured
      standardized alignment of the aiming device and the holder ensuring correct positioning of
      the collimator in subsequent radiographs.

      Presurgical protocol Each patient was prepared for surgery with oral hygiene instructions,
      scaling and root planing at least three months prior to surgery, adjunctive chemical plaque
      control, and occlusal adjustment was performed, whenever necessary. Patients were
      re-evaluated to assess clinical parameters and plaque control four weeks after initial
      therapy.

      Study protocol After the interdental areas were probed buccally and lingually/ palatally, the
      site was considered for study if the average probing pocket depth (PPD) was ≥5 mm. All
      baseline (on the day of surgery) parameters were recorded before the surgical procedure. The
      PPD, CAL and site specific plaque scores were recorded at the baseline and at the end of 3, 6
      and 9 months. Clinical parameters were recorded using a University of North Carolina no.15
      (UNC-15) color-coded Surgical procedure At the start of the surgical procedure, the patients
      were asked to rinse with 0.2 % chlorhexidine for 1 min. Area subjected to surgery was
      anesthetized by nerve block/infiltration depending on the surgical site using local
      anaesthesia. Crevicular incisions were made and the flaps were elevated by means of blunt
      dissection with the help of a periosteal elevator. The osseous defect was debrided of
      granulation tissue and the root surface was planed to remove plaque and calculus, until a
      smooth hard consistency was found. The defect's architecture was confirmed by direct
      observation and classified based on number of bony walls present. In patients selected for
      test group, in addition to open flap debridement (OFD), Siloss® bone replacement graft was
      utilized to fill the defects to the most coronal level of the osseous walls. The required
      amount of composite alloplast (Siloss®) was dispensed into a sterile dappen dish and mixed
      with patients own blood and carried to the defect site with an amalgam carrier. The
      mucoperiosteal flaps were repositioned and secured in place using interrupted sutures. The
      surgical procedure in control site included open flap debridement followed by placement of
      hydroxyapatite graft (G-graft®, Saharanpur, UP, India). The surgical area was protected and
      covered using a periodontal dressing.

      Follow-up and postsurgical care Routine postoperative instructions, oral antimicrobials
      (amoxicillin 500 mg, TID), and analgesics (Diclofenac sodium 50 mg + Paracetamol 325 mg BID)
      were prescribed for 5 days post operatively and routine post-surgical instructions were
      explained. Patients were instructed to rinse with 10 ml of 0.2 % chlorhexidine mouthwash
      twice daily for a week. They were advised to avoid chewing on the surgical site and told not
      to brush at the site or manipulate it for 10 days one week after the surgery, the dressing
      and the sutures were removed. Oral hygiene instructions were reinforced. Patients were then
      monitored at 3, 6, and 9 months. At each of the recall visits, reinforcement of oral hygiene
      measures, and supragingival scaling if required were performed. At 6 months, all soft tissue
      measurements were repeated.

      Radiographic assessment A single operator evaluated the bone fill by using digital
      subtraction technique and morphometric area analysis by using specific tools in two image
      processing software according to a previously described method.

      Digital subtraction technique and Morphometric Analysis The radiographs obtained at 3 and 6
      months were subtracted from the radiograph taken at the baseline by using commercially
      available image processing software (Adobe Photoshop® 6.0, Adobe Systems, San Jose, USA). To
      reduce brightness and contrast variations, both images were adjusted based on the levels and
      curves in the software. Before digital subtraction, both radiographs were moved in
      appropriate directions as needed, to reduce geometric distortion. These images were then
      superimposed and subtracted by selecting the image > calculation> exclusion > new channel
      tools. The excluded interdental layer was outlined by using the polygonal lasso tool and the
      layer was copied and saved as a separate joint photographic expert group document at low
      compression. Morphometric area analysis. After digital subtraction, the digitized and
      excluded interdental layer was transferred to open source software for area calculation
      (ImageJ®, Research Services Branch, NIH, Bethesda, Maryland, USA) for area calculation. The
      layer was converted into a grayscale image, and the measurement scale was set to account for
      any magnification/reduction of the radiograph because of RVG. The area of the layer was
      calculated (in mm2) by initially enclosing the entire area with the rectangular selection
      tool and then by using Analyze > Analyze Particles tool.

      Histomorphometric analysis From 3 subjects each from both the groups, bone biopsy specimens
      were obtained during crown lengthening procedures between 71/2 to 9 months. Briefly, the
      specimens were immersed in 4% buffered formalin and were subsequently dehydrated in an
      ascending series of ethyl alcohols. The specimens were then stained using haematoxylin-eosin
      for light microscopy analysis. 11 and 12 slides were prepared from SILOSS® and HA groups
      respectively. 10 regions of interest (ROIs) per slide were visualized for mineralized tissue
      volume by using an Olympus BX 53 microscope at 40X magnification. Before evaluation of bone
      sections in ImageJ, black and white image masks were created using Adobe Photoshop® according
      to a technique described by Egan et al.

      Calibrating ImageJ To calibrate Image J, a scale bar was placed on one image for each
      magnification. The file was opened with an image containing a scale bar inserted by the
      microscope or camera software that acquired the image. The length measured for the scale bar
      was entered as distance in pixels. The length of the scale bar as labelled by the microscope
      is entered as known distance and subsequent analysis was measured on this scale.

      Quantifying the Mineralized Tissue Volume in ImageJ The bone volume mask file was opened and
      the total area was selected by Edit> Selection>Select All and Click Analyze>Measure. The
      "wand tool" and shift key were used to select the black areas. Selecting Analyze>Measure will
      quantify the mineralized tissue. The Mineralized Tissue Volume was expressed as (mineralized
      tissue/total area)*100.

      Statistical Analysis Site-specific intragroup comparison between various groups was performed
      using ANOVA followed by multiple comparisons using Bonferroni correction. One-way ANOVA
      followed by the post hoc test was used for intragroup and intergroup comparison. A p-value of
      <0.05 was considered statistically significant and p-value of <0.001 was considered as highly
      significant
    

Intervention name(s): Siloss® bone graft; Hydroxyapatitie Bone graft
Intervention type(s): Biological; Biological
Intervention description(s): The osseous defect was debrided of granulation tissue and the root surface was planed to remove plaque and calculus, until a smooth hard consistency was found. The defect's architecture was confirmed by direct observation and classified based on number of bony walls present. In patients selected for test group, in addition to open flap debridement (OFD), Siloss® bone replacement graft was utilized to fill the defects to the most coronal level of the osseous walls. The required amount of composite alloplast (Siloss®) was dispensed into a sterile dappen dish and mixed with patients own blood and carried to the defect site with an amalgam carrier. The mucoperiosteal flaps were repositioned and secured in place using interrupted sutures. The surgical procedure in control site included open flap debridement followed by placement of hydroxyapatite graft (G-graft®, Saharanpur, UP, India). The surgical area was protected and covered using a periodontal dressing. Randomization was employed.; The osseous defect was debrided of granulation tissue and the root surface was planed to remove plaque and calculus, until a smooth hard consistency was found. The defect's architecture was confirmed by direct observation and classified based on number of bony walls present. In patients selected for test group, in addition to open flap debridement (OFD), Siloss® bone replacement graft was utilized to fill the defects to the most coronal level of the osseous walls. The required amount of composite alloplast (Siloss®) was dispensed into a sterile dappen dish and mixed with patients own blood and carried to the defect site with an amalgam carrier. The mucoperiosteal flaps were repositioned and secured in place using interrupted sutures. The surgical procedure in control site included open flap debridement followed by placement of hydroxyapatite graft (G-graft®, Saharanpur, UP, India). The surgical area was protected and covered using a periodontal dressing.Randomization was employed.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Treatment