THE EFFECT OF SURFACE-ROUGHNESS ON EARLY IN-VIVO PLAQUE COLONIZATION ON TITANIUM

THIS STUDY ASSESSES LN VIVO the surface roughness necessary to reduce plaque colonization on titanium after 24 hours, Three groups of 16 tit anium disks were assigned to 3 different polishing groups (A, B, and C ). The roughness was evaluated with a laser profilometer and the morph ology with a scanning electron microscope (SEM). Eight volunteers were enrolled and two stents were applied in the mandibular posterior regi on of each. Each stent supported 3 disks, one per group, The volunteer s suspended oral hygiene for 24 hours, after which the stents were rem oved; one was processed for evaluation of the adherent biomass and the other for SEM study. On each specimen a global area of 100 x 125 mu m was examined with SEM, The area was composed of five 20 x 25 mu m ran domly selected fields. For each field the density of bacteria and the morphotypes were recorded, The data quoted for the global area are cum ulative of those observed in the 20 x 25 mu m fields. Group A had a si gnificantly smoother surface than groups B and C. The adherent microbi al biomass determination and SEM evaluation revealed that group A cont ained less bacteria than the roughest group. The bacterial population was composed of cocci in group A, and of cocci and short and long rods in groups B and C, We conclude that a titanium surface with Ra less t han or equal to 0.088 mu m and Rz less than or equal to 1.027 mu m str ongly inhibits accumulation and maturation of plaque at the 24-hour ti me period and that such smoothness can be achieved in transgingival an d healing implant components.