Effect of Sterilization (Autoclave) on Wear of Tungsten-Carbide Burs Coated With Diamond Particles With Different Thicknesses

Background: Extending the lifespan and improving the physical properties of dental burs as the most extensivly used instruments have been the subject of several studies. One of the proposed methods is using surface coatings for the burs. Since the dental instruments are reused, they require sterilization. One of the possible causes of the damage to dental burs is autoclaving process. This study aimed to investigate sterilization (autoclave) effect on wear of diamond coated tungsten-carbide burs with different thicknesses. Methods: In this in vitro study, 40 tungsten-carbide dental burs (IQ DENT, Poznan, Poland) were selected, out of which 20 burs were coated with 1.5-μm-like diamond particles, and 20 burs were coated with 3.5-μm by PVD method using Swin Plasma Coating Machine. Then, the burs were randomly divided into four groups (n=10) as follow: G1: 1.5 μm thickness coated burs without sterilization; G2: 3.5 μm thickness coated burs without sterilization; G3: 1.5 μm coated with sterilization; and G4: 3.5μm thickness coated burs with sterilization. Their weights were measured before wear test.Wear test was performed and then they were re-weighted. Data were analyzed using SPSS software (version 21) as well as Two-way ANOVA and Tukey HSD supplementary tests (α=0.05). Results: Mean and standard deviation of the burs weights without sterilization in the control groups were 7.31±2.63 and 7.96±1.61 mg, respectively; and mean and standard deviation of the burs weights in the sterilization groups were 7.06±0.98 and 7.12±1.11 mg, respectively. The study results showed that "sterilization application" and "thickness of coated layer" were the main factors and their intraction had no statistically significant difference (P=0.589). Conclusions: The sterilization process had no effect on wear of diamond coated tungsten-carbide burs with different thicknesses.

Evaluation of Dentin Microroughness and Composite Bond Strength After Multiple Uses of Diamond Burs

Using a bur multiple times to prepare dental structure may produce a smoother final surface on dentin than a new one. This superficial roughness may affect adhesion with resin-based materials by modifying the substrates’ characteristics. The aim of this study was to evaluate the effect of multiple uses of diamond burs on dentin’s superficial microroughness and bond strength with resin composite when using a self-etch adhesive. Diamond dental burs were used to simulate a preparation (dentin flat surface) on extracted third molars. Samples were distributed into groups according to burs’ number of previous uses as follows: 0, 1, 5 and 10. Scanning electron microscopy images at 70x, 350x, and 1000x were used to illustrate burs’ deformation. Each specimen’s dentin microroughness was measured three times to compare between experimental groups and the micro-shear bond strength test (n=15) was performed for the 0 and 10 uses groups using a universal adhesive in a self-etching mode. Diamond crystals wear and dislodgements were evident among groups where the burs were used more times. As the number of uses increased the mean microroughness of the dentin surface decreased with significant differences between the 0 and 10 uses groups. No statistical differences between experimental groups resulted from bond strength tests. When using a universal adhesive in a self-etching mode, the number of previous uses of a diamond bur seems to have no significant effect on dentin/resin composite bond strength.

Surface Analysis Due to Implantoplasty of Failed Dental Implants Using Laser Topography - An Experimental In-Vitro Study

BACKGROUND Peri-implantitis is an inflammatory reaction surrounding the hard and soft tissues of the implant that is functional in the patient's mouth. If left untreated, this might lead to further bone loss, loosening of the implant and the ultimate failure of the implant. There are many treatment modalities that have been suggested to treat periimplantitis, but there are no set guidelines or protocols for the same. Implantoplasty seems to be a viable option for treating peri-implantitis, as it involves the smoothening of the macro geometry of the supracrestal exposed implant surface thus reducing the plaque accumulation and ultimately preventing the bacterial recolonization and preventing the implant from failure. This study was done to evaluate the smoothness and the fracture resistance of the implants treated by implantoplasty and as an effective treatment for peri-implantitis. METHODS This in-vitro study was done on 5 failed implants, in which 4 were subjected to a sequence of dental burs and prophy paste and 1 implant was kept as a control. They were subjected to laser topography analysis to determine the smoothness after implantoplasty, and their fracture resistance was also checked in Instron. RESULTS Implant no. 4 subjected to both dental burs and prophy paste was considered to be the smoothest with the laser topography of 2.049 mm compared to the control that was 3.132 mm. Also, the fracture resistance between the implants and the control was similar. CONCLUSIONS In conclusion implantoplasty is a suggested treatment option for patients with periimplantitis keeping in mind the practical difficulties of the procedure. KEY WORDS Peri-Implantitis, Implantoplasty, Dental Burs, Surface Analysis

DOES PRESTERILIZATION HAS ANY INFLUENCE ON CONSERVATIVE AND ENDODONTIC MATERIAL STERILITY, IMMEDIATELY AFTER UNPACKING AND POST EXPOSURE TO CLINICAL ENVIRONMENT FOR 15 DAYS - AN EX VIVO STUDY.

Background: Instruments used in the operative area are colonised by various microbial organisms during usage. Sterilization is an important prerequisite to avoid cross contamination. Purpose of the study: The purpose of this study was to evaluate whether presterilization has any influence on conservative and endodontic material sterility, immediately after unpacking and post exposure to clinical environment for 15 days. Methods: Gutta percha cones, Rubber dam clamps, Impression trays, Dental burs (#245 bur, Access opening bur) were tested.Materials were randomly sampled at 2 time points (t0, at package opening; t1, at 15days) during their clinical usage. Vortexing, centrifuging, streak and inoculation was done. Colony formation under aerobic conditions was observed on media before and after presterilization. Statistical analysis: Wilcoxon matched pairs test was done for comparison of data before and after pre sterilization with status of aerobic organisms at to (immediately after opening) and t1 (during clinical usage). Conclusion: Presterilization effectively eliminates cross contamination of various aerobic microorganisms in conservative and endodontic material immediately unpacked and post exposure to clinical environment for 15 days.

Management of Instrument Sterilization Workflow in Endodontics: A Systematic Review and Meta-Analysis

Endodontic treatment consists of different working procedures, such as the isolation of the operating field, pulp chamber access, and cleaning and shaping phases with at last the need of a three-dimensional filling of the canals. Each step requires a series of single-use or sterilizable instruments. We have performed a systematic review of different sterilization and disinfection procedures aiming at drawing up a disinfection and sterilization procedure to be used on endodontic instruments. A search on PubMed and Scopus was carried out using the following keywords: “endodontic sterilization,” “endodontic autoclave,” “decontamination dental bur,” “sterilization dental burs,” and “gutta-percha points sterilization.” Eligible articles were included in the qualitative and quantitative analysis. Results of the meta-analysis showed that the most effective method in sterilization is autoclaving. The qualitative analysis showed that the use of single-use or first-use instruments requires presterilization or sterilization procedures, and for reusable tools, attention must be paid to the removal of debris deposited on the blades, not easy to remove manually.

The evaluation of wear of tungsten carbide dental bur

Due to its durability, tungsten carbide has long been used as a material to produce dental burs. WC– Co burs are designed for smooth, efficient cutting and extended life. Dental burs are available in different sizes and shapes, for example round burs, pear and cylinder-shaped, egg-shaped, as well as there are various tapered ones, which enable an individual selection of the drill for the right treatment. Carbides can be used for standard crowns and bridges, for extensive surgical procedures and they should minimize damage to the existing teeth. The design of WC–Co dental bur reduces a patient’s discomfort because of the operating time and the fact that its liquidity is preserved. The head of the bur (the cutting edge) delivers optimum concentricity and strength. The shank is made from stainless steel allowing a bur to be autoclaved multiple times without the risk of corrosion. The main purpose of this study was to evaluate the wear of a tungsten carbide dental bur. The results of stereoscopy microscope and SEM/EDS analysis are presented.

Quality control of a metallic dental bur with a diamond coating

During operation, sterilization and disinfection, the surface working part of dental burs deteriorates. In this study a commercial metallic dental bur with extra coarse gradation (177-250 μ of ceramic embankment), made of a stainless steel were covered with a nickel-diamond composite was examined. The working part of the tool is round-end taper shaped and is intended for crown and bridge preparation. Analysis of microstructure was carried out using Jeol JSM-6610 LV scanning electron microscope with EDX analyzer. After 3 months of operation, the bur can be used for further work in the dental surgery.