الفهرس 
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Abstract
Chronic periodontitis is regarded as an inflammatory disease that affects the supporting tissues of teeth which could lead to bone destruction. According to the pattern of bone destruction, vertical infrabony defect could occur. Several biomaterials have been used to treat infrabony defects including bone grafts, membranes, growth factor & Enamel matrix proteins. Bone derived xenograft is a type of bone graft which has been widely used in the treatment of infra-bony defects.
Chemical treatment of root surfaces of teeth have been used as an adjunct with mechanical instrumentation. Among these chemical agents is citric acid which was found to be able to remove the smear layer and expose the collagen fibers on the root surface which would make the root surface biocompatible favoring fibroblast attachment. However, studies have found that there was no clinical significance of citric acid when it was used as a root conditioner.
Recent studies have revealed that demineralization of bone surface using citric acid resulted in the exposure of collagen and associated proteoglycans which was chemoattractant for mesenchymal cells that could be stimulated to differentiate into osteoblasts through the release of BMPs from the demineralized bone matrix. It was also shown that citric acid did not cause damage to the cells and was well tolerated when it was used for a short period of time between fifteen and thirty seconds. In a case report when citric acid was compared to decortication of an atrophic anterior maxilla that had two bone blocks placed in it. It was found on re-entry after five months that citric acid showed improved adaptation of the block to the bone bed with no sharp edges and new bone formation exceeding the graft borders.
The aim of this study was to measure BMP-2 level in the gingival crevicular fluid (GCF) during early stages of healing and to clinically assess the effect of citric acid bone surface conditioning of infra-bony defects before applying bone graft.
Twenty patients with single site of vertical infra-bony defects were selected from the outpatient clinic of oral medicine, periodontology and oral diagnosis department, faculty of dentistry, Ainshams University.
They were divided into two groups. group I had their bone surface treated with citric acid for thirty seconds before washing it off and filling the defect with xenograft while group two had their defect filled with xenograft without treating their bone surface with citric acid. BMP-2 level was measured from the GCF using periopaper during the first month after surgery. Clinical and radiographic assessment was done after six months follow-up.
Results showed that there was a significant difference between the two groups regarding the BMP-2 level in days one, three and seven with group I being the higher value while there was no significant difference in days fourteen & thirty.
Regarding the clinical and radiographic parameters, there was no significant difference between the two groups.
CONCLUSIONS