Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2015-11-17, 15:11:47 | version 1.38.0
ibuprofen 600 mg t.i.d.) administered systemi- cally. The sutures were removed after two weeks.Thedogsreceivedasoftdietandaplaque control regimen that included tooth cleaning with the use of toothbrush and dentifrice, and administration of a 0.2% chlorhexidine solution three times a week until the end of the experi- ment(eightand12weeks). Anim a l euth a n a s ia The animalswere euthanized at eight (three ani- mals) and 12 weeks (three animals) by means of an overdose of Sodium Pentothal (Abbott Labo- ratories,Chicago,Ill.,U.S.). Micro -C T eva lua tion Immediately after sacrifice at eight or 12 weeks, μCT evaluation was performed to evaluate the residualvolumeofgraftmaterial.Eachspecimen was placed on the scanning platform of a GE eXplore Locus μCT scanner (GE Healthcare, Pis- cataway, N.J., U.S.) and 360 X-ray projections were collected (80 kVp, 500 mA, 26 min total scan time). The projection images were pre- processed and reconstructed into 3-D volumes (20 μm resolution). Each volume was scaled to Hounsfield units using a calibration phantom containingairandwater(phantomplastic);aplug withinthe phantom containing HAwas used as a bone mimic for bone mineral/density calcula- tions. The 3-D data was processed and rendered (isosurface/maximum intensity projections) using MicroView (GE Healthcare). Volumes were imported into MATLAB (R2009b, MathWorks, Natick, Mass., U.S.) for automated batch analy- sis. Briefly, a fixed cylindrical volume of interest (14 mm diameter, 5 mm height) was applied to each volume. As each volume was calibrated using afixed standard, calcium phosphate, corti- cal bone, trabecular/woven bone and scaffold content were determined using predefined Hounsfield unit thresholds (> 3,000, 2,000– 3,000,750–2,000,and300–750,respectively). Residual graft material was calculated as the graft/total bone volume × 100, expressed as a percentage at eight or 12 weeks for both test groups(Table1). Sample proc es s in g The soft tissue of each mandible was dissected to leave exposed the bone surfaces. Each mandible was block-sectioned and the tissue fixedwith 4%formalin.The sampleswere dehy- drated in a graded ethanol series. The blocks were infiltrated with Technovit 7200 resin (Her- aeus Kulzer, Hanau, Germany) and polymerized withultravioletlight. The polymerized blocks were then sectioned in a buccolingualdirection.Three sliceswere ob- tained per site and reduced by micro-grinding and polishing using an EXAKT grinding unit (EXAKT, Norderstedt, Germany) to an even thickness ofapproximately15–30 lm.The slides were stained with the Lévai–Laczkó technique; the entire circumference of each section (con- taining bone, grafted granules and connective tissue) was traced manually to create individual regionsofinterest. Hi sto mo rpho me tr i c analysi s The percentages of residual graft material, con- nective tissue and new bone were calculated in relation to the total measurement area (socket walls). The central portion of each core was se- lected to avoid any potential bias. In this way, both the coronal (remaining native host bone) and the apical portions were excluded from analysis (using a safe margin of 1.5–2 mm). His- tomorphometric measurement of the samples was conducted using ImageJ software (devel- oped by the U.S. National Institutes of Health, Bethesda,Md.).Descriptiveevaluationandmor- phometric measurements were performed un- deraNikonEclipse80imicroscope(TeknoOptik, Huddinge, Sweden) equipped with the Easy Im- age 2000 system (Tekno Optik) using 91–94 lenses(Fig.2). Hi sto mo rpho me tr i c e valu ati o n Prepared samples were photographed with a digital camera using a 20× motorized optical microscope (BX51, Olympus,Japan).These pho- tographs were combined using computer soft- ware (cellSens Dimension, Olympus, Japan) to Volume 1 | Issue 1/2015 19Journal of Oral Science & Rehabilitation β-TCP b ov in e b iph a s ic b iom a teria l i ncre ase s bo ne f o rmati o n i n do g mo de l Table 1 Residual volume of graft material at eight and 12 weeks. At 12 weeks, both test groups showed a reduction in the volume of material in comparison with eight weeks. Test B showed slower resorption expressed as higher residual volume in comparison with Test A at eight and 12 weeks. Residual volume 8 weeks 12 weeks (Mean ± S.D.) (Mean ± S.D.) Te st A 63.72 ± 5.1 % 43.91 ± 1.2 % Te st B 76.22 ± 1.6 %* 58.53 ± 1.1 %* Statistical significance was set at p < 0.05. Table 1