Investigation of different electrochemical cleaning methods on contaminated healing abutments in vitro: an approach for metal surface decontamination

Electrochemical Testing of a New Polyimide Thin Film Electrode for Stimulation, Recording, and Monitoring of Brain Activity

Subdural electrode arrays are used for monitoring cortical activity and functional brain mapping in patients with seizures. Until recently, the only commercially available arrays were silicone-based, whose thickness and lack of conformability could impact their performance. We designed, characterized, manufactured, and obtained FDA clearance for 29-day clinical use (510(k) K192764) of a new thin-film polyimide-based electrode array. This study describes the electrochemical characterization undertaken to evaluate the quality and reliability of electrical signal recordings and stimulation of these new arrays. Two testing paradigms were performed: a short-term active soak with electrical stimulation and a 29-day passive soak. Before and after each testing paradigm, the arrays were evaluated for their electrical performance using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) and Voltage Transients (VT). In all tests, the impedance remained within an acceptable range across all frequencies. The different CV curves showed no significant changes in shape or area, which is indicative of stable electrode material. The electrode polarization remained within appropriate limits to avoid hydrolysis.

Reuse of healing abutments: Ethical, biological and professional training implications

Background

The aim was to estimate the prevalence of reuse of healing abutments, the methods used in disinfection and to analyze the reasons that lead to the reuse of these components by professionals who work in rehabilitation with dental implants.

Material and Methods

For this, an online data collection was carried out through a questionnaire developed in Google Forms. This questionnaire was applied to 284 specialists in implantology, randomized, of the 1,147 registered in the Regional Council of Dentistry of Rio Grande do Sul. The questionnaire was divided into three parts: the first containing the Free and Informed Consent Form; the second referring to the correspondents’ demographic data; and the third part with information on reuse, disinfection and sterilization routines used, risk perception and information from manufacturers. To estimate the prevalence in the reuse of healing abutments by implantologists, the frequency of responses was used.

Results

The results showed that almost all implantologists reuse healing abutments (98.1%). The main reasons for reuse were cost (71.2%) and practicality (26%). Regarding the limitations, 53.3% do not see limitations in its reuse, 20% associate it with increased roughness, 17.8% with the accumulation of organic matter and 8.9% with cross-infection as limitations for reuse. Already 95.3% did not receive any guidance from manufacturers on the reuse of these components. Enzymatic detergent and ultrasonic bath was the most used cleaning method (50.7%) followed by ultrasonic bath (23.3%). Autoclave was the method used for sterilization for all respondents.

Conclusions

The reuse of healing abutments is a practice adopted by implantologists in the state of Rio Grande do Sul, Brazil and most professionals do not observe limitations in this practice since these components are used repeatedly. Decontamination with enzymatic detergent and an ultrasonic bath is the most commonly used procedure associated with autoclave sterilization.

Key words:Abutment, reuse, decontamination, sterilization.

Healing Abutment Distortion in Implant Prostheses: An In Vitro Study

Little has been studied regarding the repeated usage of healing abutments and their effects on the distortion of dental implant-healing abutment hex surfaces. Additionally, implant manufacturers do not provide specific guidelines on how many times a healing abutment can be used before discarding. Therefore, we evaluated the effect of repeated screwing-unscrewing of implant-healing abutment on the healing abutment hex surface and screw head. A total of 12 Biomate implants with 4 mm diameter and 13 mm length were inserted into a synthetic bone block. The standard healing abutments of 3 mm diameter and 4 mm length were screwed onto each implant using a torque ratchet at a final torque of 30 Ncm. Immediately, the abutments were unscrewed at 30 Ncm. Then, screwing-unscrewing was repeated for 4, 8, 16, 24, 32, 40, 80, 160, 320, and 400 times and the healing abutments were scanned under the scanning electron microscope for any distortion. Distortion was graded as 0, 1, 2, and 3. Data were analyzed using SPSS 24.0. Descriptive statistics were calculated. One-way ANOVA with post hoc using Tukey’s HSD test was performed to analyze the difference in distortion at different screwing-unscrewing times. A significant level was selected at p-value = 0.05. It was found that distortion healing abutments screws were seen after 32 times screwing and unscrewing. There was a significant difference in the distortion (p-value < 0.05) after 24 times of repeated usage of healing abutment and at 160, 320, and 400 times. No surface distortions were observed at the healing abutment screw head at 4, 8, 16, 24, 32, 40, 80, 160, 320, and 400 cycles of screwing-unscrewing. It can be concluded that repeated screwing and unscrewing of the implant-healing abutments causes damage to the healing abutment hex surface. The distortion of healing abutments screws was seen after 32 times screwing and unscrewing. No surface distortions were observed on the healing abutment screw head until 400 times of screwing and unscrewing. Hence, the clinician should be cautious while using the healing abutments repeatedly.