Osteoblast differentiation on Microstructured Dental Implants: FEG SEM Study

Osteoblast differentiation on Microstructured Dental Implants: FEG SEM Study
12 March 2004
R. SAMMONS, University of Birmingham, United Kingdom
IADR
Objectives: To investigate in vitro osteoblast interactions with two grit-blasted, acid-etched, titanium implant surfaces of the same Ra value but different microstructure, as prepared for clinical use, using high resolution SEM. Methods: DENTSPLY Friadent implants with new surface (NS; porous microstructure) and Friadent DPS (non-microporous) implants were placed in nylon pockets in contact with rat calvarial bone fragments for 2 or 4 weeks in mineralisation-permissive medium (n = 3). Bone was detached when the pockets were opened and the underlying migrated-cell layer was examined using a Philips FEG SEM. EDS was used to detect mineral ions. Results: The extent of cell cover appeared similar on NS and DPS, with areas of multicellular layers and areas where individual cells formed an interconnected network, spanning grit-blasting crevasses. Cells attached to the edges of pores in the NS surface, spanning them, whereas on DPS they conformed closely to the surface. After 2 weeks, on DPS a mass of fine collagen-like fibres was present between cell layers; thicker, more organised bundles of fibres were seen on NS. After 4 weeks, cells on DPS formed a closely adherent layer with no intervening gaps. Discreet, raised 5-10 micron bone nodule-like structures were seen on both surfaces. These were themselves covered with 10-500nm diameter, globular structures. Calcium was detected in nodules but was not found in adjacent areas of the cell sheet or implant surface. Further elemental and ultrastructural analysis is necessary to determine the composition of these structures. Conclusions: Osteoblast-like cell morphology, attachment and the location and appearance of extracellular matrix differed on dental implant surfaces of the same Ra value but different microstructure. Calcified nodule-like structures were seen on both surfaces, suggesting that surface topography may not influence the processes leading to their formation. This study was funded by DENTSPLY Friadent, Mannheim, Germany.