Comparative evaluation of roughness of titanium surfaces treated by different hygiene instruments

Abstract

Purpose: The use of appropriate instruments to clean surfaces with minimal change, is critical for the successful maintenance of a dental implant. However, there is no consensus about the type and methodology for such instruments. The aim of this study was to characterize changes in the roughness of titanium surfaces treated by various scaling instruments.

Methods: Thirty-seven identical disks (5 mm in diameter) were investigated in this study. The specimens were divided into eight groups according to the types of instrumentation and the angle of application. Ultrasonic scaling systems were applied on a titanium disk to simulate standard clinical conditions. The equipment included a piezoelectric ultrasonic scaler with a newly developed metallic tip (NS group), a piezoelectric ultrasonic scaler with a conventional tip (CS group), a piezoelectric root planer ultrasonic scaler with a conventional tip (PR group), and a plastic hand curette (PH group). In addition, the sites treated using piezoelectric ultrasonic scaler systems were divided two sub-groups: 15 and 45 degrees. The treated titanium surfaces were observed by scanning electron microscopy (SEM), and the average surface roughness (Ra) and mean roughness profile depth (Rz) were measured with a profilometer.

Results: SEM no significant changes in the titanium surfaces in the NS group, regardless of the angle of application. The PH group also showed no marked changes to the titanium surface, although some smoothening was observed. All CS and PR sites lost their original texture and showed irregular surfaces in SEM analysis. The profilometer analysis demonstrated that the roughness values (Ra and Rz) of the titanium surfaces increased in all, except the PH and NS groups, which showed roughness decreases relative to the untreated control group. The Ra value differed significantly between the NS and PR groups (P<0.05).

Conclusions: The results of this study indicated that changes in or damage to titanium surfaces might be more affected by the hardness of the scaler tip than by the application method. Within the limitations of this study, the newly developed metallic scaler tip might be especially suitable for peri-implant surface decontamination, due to its limited effects on the titanium surface.

Keywords: Dental implants; Dental instruments; Peri-implantitis; Periodontal debridement.

Figure 1

Scaler tips used in this study. (A) Piezoelectric ultrasonic scaler with a newly developed metallic tip, (B) piezoelectric ultrasonic scaler with a conventional tip, (C) root planner ultrasonic scaler, (D) hand scaler.

Figure 2

Preparation of the test site in titanium specimen.

Figure 3

Description of experimental methods. The ultrasonic scalers were used with moderate finger pressure, for 30 seconds, at 15 (A) and 45 degrees (B) at 25 kHz set on highest power.

Figure 4

Scanning electron microscopy images of the titanium surfaces with various treatments showed differences depending upon the given treatment. The control group clearly showed the machined grooves (A). The plastic curette and a newly developed metallic tips did not appear to significantly affect the titanium surface, especially after treatment. However some smoothening of the titanium surface appears to have occurred (B-D). In addition, the difference in angles did not appear to affect the outcome of the experiment. The groups using conventional scaler tip clearly showed the damages induced by the tips, both at 15 and 45 degrees. Also, the images showed that circumferential milling on the titanium surface have been scraped (E, F). Other groups using piezoelectric root planer also showed similar results to groups using conventional scaler tip (G, H).

Figure 5

Results from profilometer analysis. Graph showing the average surface roughness (Ra) and mean roughness profile depth (Rz) in each group. Ra and Rz were similar in the NS, PH and control groups, but increased in the CS and PR groups, indicating that the conventional ultrasonic scaler and the root planer had significant effects on the titanium surface. NS: piezoelectric ultrasonic scaler with a newly developed metallic tip, CS: piezoelectric ultrasonic scaler with a conventional tip, PR: piezoelectric root-planer/ultrasonic scaler with a conventional tip, PH: plastic hand curette.