3 modalities were studied : ( 1 ) control , in which no membrane and therefore no cell occlusion was used , ( 2 ) flap occlusion , in which the internal surface of the flap was lined with the membrane preventing contribution of cells from the flap , ( 3 ) bone occlusion , in which the reduced alveolar bone was lined with the membrane preventing contribution from bone cells .
C0007634
cell
C0007603
membrane