Atomic Force Microscopic Study of Commercially Available Implant Abutments

A Microscopy Evaluation of Emergence Profile Surfaces of Dental Custom CAD-CAM Implant Abutments and Dental Implant Stock Abutments

Recently, due to the high demand for dental implants, the use of dental implant stock abutments has increased significantly, especially dental custom CAD/CAM implant abutments milled by dental technicians in their laboratories. The purpose of this study is to analyze the surface quality of the emergence profile of dental custom CAD/CAM implant abutments made by a non-industrial milling machine, compared to original and compatible dental implant stock abutments made by industrial machines. Thirty dental implant abutments were divided into six study lots. Lot 1 (control group): original dental implant stock abutments-industrial machined; lot 2 (study group): compatible dental implant stock abutments-industrial machined; lots 3, 4, 5, and 6 (study groups): compatible custom CAD/CAM dental implant abutments-non-industrial milled with hyperDENT CAM software and Paragon Tools. The Nikon SMZ745T stereomicroscope was used to analyze the emergence profile surface of each dental implant abutment. The structure of the analyzed surfaces did not show significant differences between original and compatible abutments that were industrially machined. As for the customized dental implant abutments, the greatest similarity with the original was obtained for lot 6, and a significant statistical difference was obtained for lot 4. Stepover and Feed Rate parameters of the milling process influenced the surface roughness of the emergence profile for the customized dental implant abutments. The digital technology of non-industrial milling compatible custom CAD/CAM dental implant abutments is reliable and within the correct milling parameters.

Effects of Hard Thin-Film Coatings on Adhesion of Early Colonizer Bacteria Over Titanium Surfaces

PURPOSE

The purpose of this in vitro study was to evaluate the effect of diamond-like carbon (DLC) and titanium (Ti) nitride coatings over Ti surfaces on the adhesion of early colonizer bacteria.

MATERIALS AND METHODS

Specimens were divided into 3 groups (n = 10) according to different surface modifications: titanium nitride (TiN)-coated Ti discs (experimental group 1), DLC-coated Ti discs (experimental group 2), and uncoated polished Ti discs (control group). Discs were incubated in bacterial cell suspension (Streptococcus mutans and Streptococcus sanguis) for 1 hour, and the single colonies formed by adhering bacteria were counted by fluorescence microscopy. Surface roughness and topography were examined by atomic force microscopy.

RESULTS

The surface roughness of DLC was lower than TiN coating and the control group. Statistically significant reduction of the number of adherent bacteria was observed on DLC-coated surfaces.

CONCLUSIONS

DLC coating over Ti surfaces strongly inhibits the adhesion of early colonizer oral bacteria.

Effect of heat treatment after accelerated aging on phase transformation in 3Y-TZP

Our purpose was to investigate the effect of heat treatment on the reversibility of the tetragonal to monoclinic transformation in 3Y-TZP, and associated surface roughness. The goals were to determine the onset temperature of the reverse transformation, and characterize surface roughness after accelerated aging, and after aging followed by heat treatment. 3Y-TZP disc-shaped specimens were sintered at temperatures from 1300 to 1550 degrees C. The reversibility of the transformation was investigated by X-ray diffraction (XRD) after accelerated aging, followed by heat treatment at temperatures from 350 degrees C up to 850 degrees C. The surface roughness (R(rms)) was measured by atomic force microscopy after polishing, after accelerated aging for 1 or 10 h, and after aging followed by heat treatment. XRD showed that the fraction of m-phase increased linearly with grain size after aging for 10 h (1.0-29.8%). The transformation was reversed for all groups after heat treatment at 850 degrees C/min., with only trace amounts of m-phase remaining for the group sintered at 1550 degrees C. A significant increase in mean surface roughness was observed after accelerated aging (1.59-7.45 nm), compared to polished groups (0.83-1.0 nm). However, the mean surface roughness after accelerated aging for either 1 or 10 h, followed by heat treatment at 850 degrees C/min. (1.18-2.1 nm), was not significantly different from that of the polished groups. This was attributed to the reverse transformation. XRD revealed that the monoclinic to tetragonal transformation, was complete after heat treatment at 500 degrees C for 1 min, for specimens sintered at 1550 degrees C and aged 10 h.

Surface Analysis Methods of Biomaterials Used in Oral Surgery: Literature Review

Titanium is the most frequently used biomaterial in oral surgery because of its positive physical and chemical properties. Clinical studies proved that the properties of titanium can be improved by surface modification techniques. To study the surface of biomaterials, the positive effects of the coatings, the response of the organism (corrosion resistance, physical and chemical stability, the thickness of various coatings, biocompatibility), one must choose and use the adequate analytical method for one's goal. In this article, the authors present the most frequently used analytical methods for the study of the surface morphology and composition of biomaterials. Also, they outline the advantages and disadvantages of specific analytical methods and the field where they are used.