Recai Zan

Temperature Rises During Application of Er:YAG Laser Under Different Primary Dentin Thicknesses

OBJECTIVE The present study investigated the effects of the Er:YAG lasers different pulse repetition rates on temperature rise under various primary dentin thicknesses. BACKGROUND DATA The Er:YAG laser can be used for restorative approaches in clinics and is used to treat dental caries. There are some reports that explain the temperature rise effect of the Er:YAG laser. Recently, the Er:YAG laser has been found to play an important role in temperature rises during the application on dentin. METHODS Caries-free primary mandibular molars were prepared to obtain dentin discs with 0.5, 1, 1.5, and 2 mm thicknesses (n=10). These discs were placed between the Teflon mold cylinders of a temperature test apparatus. We preferred three pulse repetition rates of 10, 15, and 20 Hz with an energy density of 12.7 J/cm2 and a 230 μs pulse duration. All dentin discs were irradiated for 30 sec by the Er:YAG laser. Temperature rises were recorded using an L-type thermocouple and universal data loggers/scanners (E-680, Elimko Co., Turkey). Data were analyzed by two-way ANOVA and Tukey tests. RESULTS Whereas the lowest temperature rise (0.44±0.09 °C) was measured from a 10 Hz pulse repetition rate at a dentin thickness of 2 mm, the highest temperature rise (3.86±0.43 °C) was measured from a 20 Hz pulse repetition rate at a 0.5 mm dentin thickness. CONCLUSIONS Temperature rise did not reach critical value for pulpal injury in any primary dentin thicknesses irradiated by a high repetition rate of the Er:YAG laser.

Antibacterial Effects of Two Different Types of Laser and Aqueous Ozone Against Enterococcus faecalis in Root Canals

OBJECTIVE The purpose of this study was to investigate the antibacterial effects of two different types of laser and aqueous ozone in human root canals infected by Enterococcus faecalis. BACKGROUND DATA Many techniques have been developed to find an alternative to sodium hypochlorite as a disinfection agent for infected root canals. However, no study has evaluated the exactly the same antimicrobial agent with sodium hypochlorite (NaOCl). METHODS Eighty mandibular premolar teeth with single roots and canals were selected. Following root canal preparation and irrigation, sterilization was performed in an autoclave. E. faecalis was incubated in the root canals and kept at 37°C for 24 h. The teeth contaminated with E. faecalis were divided into one negative control group (NaOCl) and three experimental groups; (Er:YAG laser, KTP laser, and aqueous ozone groups)(n=20). A disinfection procedure was performed for 3 min in order to standardize all groups. After this procedure, the microbial colonies were counted. RESULTS The results indicated that whereas the NaOCl group exhibited the highest antibacterial effect among all groups, the aqueous ozone showed the highest antibacterial effect among the experimental groups. Whereas a statistically significant difference was noted between the aqueous ozone and laser groups (p<0.05), the difference between the Er:YAG and KTP lasers was not statistically significant (p>0.05). CONCLUSIONS The results showed that when aqueous ozone was applied with the aim of disinfecting the root canals, it exhibited a higher antibacterial effect than the KTP and Er:YAG lasers. However, the antibacterial effect of the aqueous ozone was insufficient when compared with NaOCl.

The Effects of Er:YAG, Nd:YAG, and Ho:YAG Laser Surface Treatments to Acrylic Resin Denture Bases on the Tensile Bond Strength of Silicone-Based Resilient Liners.

OBJECTIVE The present study was to assess the effect of surface treatments of Er:YAG, Nd:YAG, and Ho:YAG lasers on the tensile bond strength of a silicone-based resilient liner to an acrylic denture in an in vitro setting. METHODS Experimental dumbbell-shaped specimens (75 mm) were produced by combining two acrylate pieces fabricated from heat-polymerized acrylic resin (36 mm) with 3 mm of Molloplast(®)-B filling between them. The specimens (n=200) were randomly divided in half for thermocycling, and each 100 specimen set was randomized into five groups (n=20) with different surface treatments: control (no surface treatment), sandblasting, Er:YAG laser, Nd:YAG laser, and Ho:YAG laser. A tensile bond strength test was performed. The effect of the laser surface treatments was examined with scanning electron microscopy. RESULTS Only the Er:YAG laser increased the tensile bond strength compared with the other treatments. The other laser groups showed lower bond strengths. The Ho:YAG laser resulted in considerably reduced tensile bond strength. The scanning electron microscopy images showed that applying laser surface treatments modified the surface of the denture base resin. CONCLUSIONS There was not an overall improvement with the use of the studied laser modalities in the adhesion quality of resilient denture liner to acrylic resin, although Er:YAG laser showed a potential to improve their adhesion. These laser modalities need to be subjected to further studies to determine optimal setup for use in prosthodontics.

Antibacterial Efficacy of Aqueous Ozone in Root Canals Infected by Enterococcus faecalis.

Background: In endodontics, the elimination of resistant bacteria such as Enterococcus faecalis plays an important role for treatment success in root canals. Therefore, new alternative irrigants (instead of sodium hypochlorite) have been researched to achieve ideal endodontic treatment. Objectives: The aim of the present study was to evaluate and to compare the antibacterial effect of aqueous ozone with different concentrations and techniques of application (manual and ultrasonic) against E. faecalis in human root canals. Patients and Methods: Eighty single-root mandibular premolar teeth were selected, prepared and sterilized. E. faecalis was incubated in the root canals and kept at 37°C for 24 h. The teeth were divided into four main groups each has 20 members: NaOCl (positive control) group; 8 ppm aqueous ozone group; 12 ppm aqueous ozone group; and 16 ppm aqueous ozone group. While half of the specimens were disinfected with aqueous ozone by manual technique, the other half was disinfected with the aqueous ozone by ultrasonic technique. Conventional irrigation technique was simultaneously applied with ultrasonic vibration that was produced by VDW.ULTRA device. The disinfection procedures were performed for 180 s to ensure standardization of all the working groups. Paper points (placed in the root canals before and after the disinfection procedures) were transferred to Eppendorf tubes containing 0.5 mL of brain heart infusion broth. Then, 50 μL of the suspension was inoculated onto broth agar media. Microbial colonies were counted, and the data were evaluated statistically using 2-way analysis of variance (ANOVA) and Tukey tests. Results: Although the antibacterial effect of 16 ppm aqueous ozone using a manual technique had an insufficient effect, its ultrasonic application technique resulted in complete disinfection in the root canals. Conclusions: The bactericidal activity of high concentration of aqueous ozone combined with ultrasonic application technique showed efficacy similar to that of 5.25% NaOCl in root canals.

Antibacterial Efficacy of Super-Oxidized Water on Enterococcus faecalis Biofilms in Root Canal

Background The success of endodontic treatment depends on a few crucial factors. One of these factors is the complete chemomechanic preparation of root canal against various bacteria. In particular, the effect of resistant bacteria may cause intense pain with flare-up and formation of periapical lesions. Therefore, the strong effect of irrigants plays an important role in terms of the complete elimination of these bacteria to achieve long-term successful treatment. Objectives The aim of this study was to investigate the antibacterial effects of super-oxidized water (SPO) in root canals infected with Enterococcus faecalis biofilms. Methods One hundred twenty single-root, premolar teeth were selected. Initially, the teeth were prepared and then disinfected. E. faecalis were inoculated and kept at 37°C for 24 hours in the root canals. The re-inoculation procedure was repeated on the first, fourth, seventh, and tenth days. The infected root canals were divided into one negative (saline) and one positive (sodium hypochlorite) control group and four experimental groups (super-oxidized water: 1, 2, 3, or 5 minutes) (n = 20). Paper points were placed in the root canals to control and evaluate the biofilm formation. Biofilms were counted on blood agar plates, and data was evaluated and statistically analyzed using one-way ANOVA and Tukey’s test. Results Although sodium hypochlorite (NaOCl) showed no statistically significant difference when compared with three and five minutes of SPO irrigation (P > 0.05), NaOCl showed statistically significant differences among all other groups (P < 0.05). Conclusions Super-oxidized water indicated a remarkable and similar bactericidal effect to that of traditional NaOCl against E. faecalis biofilms. In terms of successful endodontic treatment approaches, super-oxidized water may be used as an effective irrigation solution in clinics.

Evaluation of temperature rises during the application of different power levels of potassium titanyl phosphate and neodymium-doped:yttrium aluminum garnet lasers to external primary root canals

Background/purpose Nowadays, laser systems play crucial roles in endodontic treatments. Therefore, these systems should be investigated in terms of parameters that may prevent periodontal tissues damages during laser irradiation. In this context, the purpose of this study was to evaluate temperature rises during the application of different power levels of potassium titanyl phosphate (KTP) and neodymium-doped:yttrium aluminum garnet (Nd:YAG) lasers to external primary root canals. Materials and methods Sixty primary mandibular molars were selected and chemomechanical preparation was performed. KTP laser treatment was applied to 30 of these 60 samples and the remaining 30 received Nd:YAG laser treatment. The teeth samples received laser application (KTP or Nd:YAG) at three different power levels (1 W, 1.5 W, and 2 W, respectively, applied to 10 samples from each group). Nine holes were drilled (1 mm in diameter) through the level of the coronal, middle, and apical third of each tooth canal to provide entry for a Type L thermocouple wire, which was used to measure temperature changes. Data were assessed with two-way analysis of variance and the Tukey test. Results All power levels indicated statistically significant differences between Nd:YAG and KTP laser systems (P < 0.05). Moreover, the same regional (apical, middle, and coronal) comparisons performed between Nd:YAG and KTP laser systems showed statistically significant differences (P < 0.05). Conclusion All parameters of KTP laser indicated lower temperature rises than Nd:YAG laser. Therefore, KTP laser may be preferable to protect the periodontal tissues from harmful thermal effects during the endodontic treatment of primary root canals.

Shear Bond Strength of Composite and Ceromer Superstructures to Direct Laser Sintered and Ni-Cr-Based Infrastructures Treated with KTP, Nd:YAG, and Er:YAG Lasers: An Experimental Study

OBJECTIVE The aim of this study was to examine the shear bond strength (SBS) of ceromer and nanohybrid composite to direct laser sintered (DLS) Cr-Co and Ni-Cr-based metal infrastructures treated with erbium-doped yttrium aluminum garnet (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), and potassium titanyl phosphate (KTP) laser modalities in in vitro settings. METHODS Experimental specimens had four sets (n = 32) including two DLS infrastructures with ceromer and nanohybrid composite superstructures and two Ni-Cr-based infrastructures with ceromer and nanohybrid composite superstructures. Of each infrastructure set, the specimens randomized into four treatment modalities (n = 8): no treatment (controls) and Er:YAG, Nd:YAG, and KTP lasers. The infrastructures were prepared in the final dimensions of 7 × 3 mm. Ceromer and nanohybrid composite was applied to the infrastructures after their surface treatments according to randomization. The SBS of specimens was measured to test the efficacy of surface treatments. Representative scanning electron microscopy (SEM) images after laser treatments were obtained. RESULTS Overall, in current experimental settings, Nd:YAG, KTP, and Er:YAG lasers, in order of efficacy, are effective to improve the bonding of ceromer and nanohybrid composite to the DLS and Ni-Cr-based infrastructures (p < 0.05). Nd:YAG laser is more effective in the DLS/ceromer infrastructures (p < 0.05). KTP laser, as second more effective preparation, is more effective in the DLS/ceromer infrastructures (p < 0.05). SEM findings presented moderate accordance with these findings. CONCLUSIONS The results of this study supported the bonding of ceromer and nanohybrid composite superstructures to the DLS and Ni-Cr-based infrastructures suggesting that laser modalities, in order of success, Nd:YAG, KTP, and Er:YAG, are effective to increase bonding of these structures.

Apical extrusion of intracanal biofilm using ProTaper Gold, WaveOne Gold,Twisted File Adaptive, OneShape New Generation and K3XF

Objective: To evaluate the bacterial extrusion during instrumentation with different nickel titanium (NiTi) engine-driven instruments. Methods: Ninety extracted single-canal human mandibular incisor teeth were inoculated with Enterococcus faecalis to obtain biofilm formation and were randomly divided to 6 groups (n=15). One group served as the control and was not instrumented; the other groups were prepared with ProTaper Gold (PTG; Dentsply Maillefer, Ballaigues, Switzerland), WaveOne Gold (WOG; Dentsply Maillefer), Twisted File Adaptive (TFA; SybronEndo, Orange, CA, USA), One Shape New Generation (OSNG; MicroMega, Besancon, France), and K3XF (SybronEndo) instruments. Bacteria extruded beyond the apical foramen were quantified in colony-forming units per milliliter. The number of colony-forming units in the remaining biofilm was determined for each sample. Data were analyzed using the one-way analysis of variance (ANOVA) and Tukey post-hoc tests. Results: All NiTi instruments resulted in different quantities of bacterial extrusion. The TFA group caused most bacterial extrusion (P<0.05). The PTG and WOG groups caused less bacterial extrusion than the OSNG and K3XF groups (P<0.05), but there was no statistically significant difference between the PTG and WOG groups (P>0.05). Conclusion: PTG and WOG are preferable system in terms of successful endodontic treatments. The amount of bacterial extrusion is associated with the metallurgy and design of the instrument used.

Apical extrusion of intracanal biofilm after root canal preparation using Revo-S, Twisted File Adaptive, One Shape New Generation, ProTaper Next, and K3XF instrumentation systems

1Department of Endodontics, Cumhuriyet University Faculty of Dentistry, Sivas, Turkey 2Department of Endodontics, Erciyes University Faculty of Dentistry, Kayseri, Turkey 3Department of Microbiology, Cumhuriyet University Faculty of Medicine, Sivas, Turkey 4Department of Endodontics, Adnan Menderes University Faculty of Dentistry, Aydin, Turkey 5Department of Restorative Dentistry, Cumhuriyet University Faculty of Dentistry, Sivas, Turkey

BACTERICIDAL EFFECTS OF VARIOUS IRRIGATION SOLUTIONS AGAINST STAPHYLOCOCCUS AUREUS IN HUMAN ROOT CANAL

Purpose: The aim of the present study was to evaluate and to compare the antibacterial effects of various irrigation solutions against Staphylococcus aureus (S. aureus) in human root canals. Materials and Methods: 120 single-root mandibular premolar teeth were selected. The teeth were prepared and sterilized. S. aureus was incubated in the root canals and kept at 37°C for 24h. The infected root canals were divided into one positive (saline) and one negative (sodium hypochlorite) control, and four experimental groups [Ethylene-diaminetetra-aceticacid, Chlorhexidine Gluconate, Super-oxidized water(SPO), Aqueous ozone] (n=20). Flow rate of irrigation was applied with 5 mL/min flow rate for 3 min to ensure standardization among all study groups. Following the irrigation, paper points were placed in the root canals and then transferred in sterile eppendorf. Remaining bacteria were counted on blood agar plates and the data were analyzed using one-way ANOVA and Tukey’s test. Results: Although there were statistically significant differences among SPO and other experimental groups (p<0.05), there was no statistically significant difference between SPO and NaOCl (p>0.05). Conclusion: Super-oxidized water may be recommended as an alternative irrigation solution instead of NaOCl against S. aureus in root canals.