الفهرس 
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Abstract
This study was conducted to evaluate experimentally the effect of porous silica–calcium phosphate nanocomposite (SCPC) material with and without recombinant human bone morphogenetic protein rh(BMP-2) in alveolar ridge augmentation in saddle-type defects.
This study was conducted on a total of 24 dogs that were divided into two groups. Each group included 12 dogs that were further subdivided into three subgroups each.
Group A: included 12 dogs where mandibular premolars were surgically extracted and saddle-type defects (12mm x 7mm mesiodistally x apico-coronally) 2 defects/jaw quadrant were created in each dog. 8 defects received a block of (SCPC) material loaded with rh(BMP-2). 8 defects received the porous (SCPC) material alone, and 8 defects in 4 dogs were left empty. The defects were covered by titanium mesh. Due to wound failure in all but one of the experimental animals another group was added avoiding the possible causes of failure as follows;
Group B: included 12 dogs where mandibular premolars were surgically extracted and saddle-type defects (12mm x 7mm mesiodistally x apico-coronally) 2 defects/jaw quadrant were created in each dog. 8 defects received (SCPC) material in a powder form loaded with rh(BMP-2). 8 defects received the (SCPC) material alone, and 8 defects in 4 dogs were left empty. The defects were covered by a collagen membrane.
The animals were sacrificed at 8 and 16 weeks and specimens were processed and stained with H&E and Gomori trichrome stain for qualitative and quantitative assessment. Quantitative assessment included evaluation of bone height gain and bone surface area.
Results showed that:
• Silica–calcium phosphate nanocomposite (SCPC) material loaded with recombinant human bone morphogenetic protein (rhBMP-2) is an effective method in the treatment of large mandibular saddle shape defects for alveolar ridge augmentation.
• The use of (SCPC)+ (rhBMP-2) resulted in acceleration and enhancement of bone formation.The microscopic picture of newly formed bone was characterized by high density and good quality, and uniform trabecular pattern.
• The use of the SCPC alone resulted in favourable bone formation and quality of bone however less than that obtained by the SCPC+Rh(BMP-2).
• Both (SCPC) and (rhBMP-2) are biocompatible and didn’t result in abnormal reactions.
• The (SCPC)material represents an excellent scaffold for (rhBMP-2) that provided sustained release favorable for bone regeneration.
• The use of titanium mesh is associated with a large percentage of failure.
• The use of powder form of the SCPC graft material is more convenient in alveolar ridge defects.