Clinical and Histomorphometrical Findings of Differently Structured Implants

Clinical and Histomorphometrical Findings of Differently Structured Implants
I. NERGIZ1, P. SCHMAGE1, N. ARPAK2, H. BOSTANCI2, W. NIEDERMEIER3, and U. PLATZER1, 1 University of Hamburg, Germany, 2 University of Ankara, Turkey, 3 University of Cologne, K??ln, Germany
March 2004
Clinical Implant Studies
Objectives: The purpose of this study was to correlate the clinical parameters pocket probing depth (PPD) and implant stability with the bone density around unloaded and loaded osseointegrated implants under standardised conditions. Methods: 180 step-cylinder implants (Frialit-2, Dentsply Friadent, Mannheim, Germany) with five different surface structures (each 36 machined, deep profile structured DPS, titanium plasma-sprayed TPS, hydroxyapatite-coated HA, sol-gel-hydroxyapatit-coated SGHA) were inserted into the mandibles of 18 sheep dogs. During the implant preparation bone samples were taken of each implant site. After a healing period of 3 months half of the implants were loaded (LO) with fixed prostheses, the rest remained unloaded (UL). 3, 6 and 9 months after placement, PPD and Periotest values (PTV) were determined. After the last check up the mandibles were sectioned and specimens obtained using the sectioning and grinding technique, and were analysed histo-morphometrically (Zeiss Axiophot, Oberkochen, GERMANY; NIH-Image 1.47). Results: ANOVA revealed no significant differences of the PPD between the different implant surfaces (4¨±2mm) for UL and between (3¨±1mm) and (3.5¨±0.5mm) for LO. The PTV of machined and of SGHA-implants varied between (-1¨±1.5) and (-2¨±1); all implants of these surface structures failed during the investigation and therefore, could not be analysed histologically. The PTV of DPS-, TPS- and HA- implants decreased after 9 months from ÇƒÏ2.5¨±0.8 not significantly to ÇƒÏ3¨±0.6 for UL, or ranged between ÇƒÏ4.5¨±0.7 (DPS, HA) and ÇƒÏ6¨±0.3 (TPS) for LO. Bone density within the 50¨µm interface zone amounted to 50% for UL and showed no significant differences for DPS-, TPS- and HA- implants, but was increased significantly (p<0.01) to 75% in LO. Conclusion: The assessment of clinical parameters was not reliable to quantify osseointegration, although an improvement of bone density could be determined along with functional loading.