The Use of Expanded Mesenchymal Stem Cells (MSCs) Loaded on Platelet Rich Fibrin (PRF) Scaffold in Treatment of Induced Vertical Alveolar Ridge Defects: An Experimental Study

Abstract

Alveolar ridge deficiency continues to be a challenge in implant dentistry. A lot of techniques have been developed to treat various types of ridge deficiency with varying degrees of success. Tissue engineering has emerged as one of the most promising techniques in bone regeneration. In involves the interaction of cells, biocompatible scaffold, growth factors and mechanical stimulus suitable to support bone formation. Scaffold material used for bone regeneration should fulfill certain criteria such as; biocompatibility, biodegradability, pore size and mechanical properties. Platelet rich fibrin developed by Choukren has been used as growth factors in multiple techniques of bone regeneration. Recently, it has been used in tissue engineering purposes as a carrier for cells and also as a scaffold material to support bone regeneration. Also Hydrxyapetite and β-tricalcium phosphate which were an evidenced material in bone regeneration has been used successfully in bone tissue engineering. The present study was conducted on 10 dogs of both sexes, the mean age of them was 1.5 years and their weights ranged from 25- 40 kg. The study involved in-vivo and in-vitro part. In the in-vivo part, all the dogs underwent two stage surgical procedures. Stage I: creation of three vertical alveolar ridge defects in each dog with dimensions 10 mm mesio-distal x10 mm apico-coronal x 8 mm bucco-lingual and harvesting of gingival tissues. Stage II: augmentation procedures where the defects previously formed in stage I were randomly assigned to one of the following groups Summary 117 Group I: defects were augmented with PRF membranes loaded with GMSCs Group II: defects were augmented with PRF membranes loaded with GMSCs together with the composite block. Group III: defects were augmented with PRF membranes in addition to composite block without GMSCs to act as a positive control group. In- vitro part involve isolation of GMSCs from the harvested gingival tissues, cells characterization, culture and expansion. The results of our study demonstrated bone formation in all groups with varying degrees. The quality of bone formed varied between groups with group I showed the highest amount of bone maturation with well formed lamellae and largest number of osteocytes. The total amount of bone formed was highest in group II with lesser degree of bone maturation than group I. Healing at the defect border was highest in group I where the defect borders couldn't be distinguished from the graft material. These borders could be easily detected in group III with statistically significant difference between group I and III. Based on these results, it could be concluded that PRF is a suitable scaffold for MSCs and that the combination of PRF and GMSCs could yield significant amount of bone formation. HA/ TCP is also a suitable scaffold however, it requires longer period to yield the same amount of bone formation.