BME MS Defense: Daniel Mints
Quantitative and Qualitative Analysis of Dental Implant Surfaces: Evaluation of Wear Behavior during the Insertion Process
Supervised by Professor Luiz Meirelles
The surfaces of modern dental implants have been modified to enhance osseointegration. The work in Chapter 1 aims to examine the surface integrity associated with implant placement, to determine whether the surface topography of common modifications is retained after implantation. Turned (T), acid-etched (AE) and anodized (Ano) implants were prepared. Implants were inserted into Grade 30 polyurethane blocks using a standard drilling protocol at max. torque of 37 N*cm. Qualitative analysis of the apical region and implant threads of preinserted and postinserted implants was done by scanning electron microscopy and quantitative analysis of the implant threads was performed by interferometry. Roughness parameters were calculated and compared before and after insertion, showing reduction in prominent peaks. Surface changes were clearly found only in Ano implants, concentrated mostly on the tops of threads and apical region.
The current results indicate some material loss after insertion. In chapter 2, the study is expanded to a wide range of commercially available implants. Nobel BioCare (Mk3 and Mk4), 3i Nanotite (parallel and tapered) and Astra OsseospeedTX implants were inserted into Grade 30 polyurethane foam. Implant insertion torque was measured by a drilling unit. Surface topography was evaluated before and after implant insertion by interferometry and scanning electron microscopy. Interferometry measurements of the implants were split between apical region and implant body. Higher insertion torques were observed in NobelBiocare Mk4 and 3i Tapered Implants.
MK4 (apex and implant body) and 3i Parallel (implant body) revealed decreased peak height values over 0.3µm after implant insertion. SEM analysis revealed localized damage to both the apex and implant body, which may be related to the change in surface roughness parameters. The apical cutting edges of Nobel implants showed chipping of the oxide layer, exposing the underlying material. The apical threads of tapered 3i implants were flattened due to the insertion process. Astra implants had scratches following the direction of insertion and voids that lacked the nanostructures found elsewhere. Overall, it has been shown that micro- and nanofeatures are affected by the insertion procedure. In a clinical situation, these changes may compromise initial healing with the presence of peri-implantar debris.