Comparative evaluation of cyclic fatigue resistance of four different nickel-titanium rotary files with different cross-sectional designs and alloy properties.

OBJECTIVE: The purpose of the present study was to evaluate the cyclic fatigue resistance of F6 SkyTaper (Komet Brasseler, Lemgo, Germany), K3XF (SybronEndo, Orange, CA, USA), new generation OneShape (Micro Mega, Besancon, France) and TRUShape 3D conforming files (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA). MATERIAL AND METHODS: Ten instruments from each group were selected and allowed to rotate using a low-torque motor in a stainless steel block with 1.5 mm diameter, 3 mm radius of 60° angle of curvature at the manufacturer's recommended speed, and the number of cycles (NCF) from the beginning to the fracture was recorded. The data were analyzed using one-way ANOVA followed by post-hoc Tukey's test (P = 0.05). RESULTS: The ranking of the groups from the highest to the lowest NCF was as follows: F6 SkyTaper (959 ± 92), K3XF (725 ± 71), TRUShape (575 ± 84) and OneShape (289 ± 58). Statistically significant differences were detected between all groups (P < 0.05). CONCLUSION: Within the limitations of this study, F6 SkyTaper instruments presented the highest cyclic fatigue resistance among the tested instruments. The S-shaped cross-sectional design of F6 SkyTaper instruments could be the most important factor on the superior cyclic life span of these instruments. CLINICAL RELEVANCE: In endodontic practice, preferring the instruments with higher cyclic fatigue resistance would help to minimize the risk of instrument fractures; therefore especially during the preparation of curved canals, instruments with smaller core area and less cross-sectional metal mass, which could lead higher flexibility, can be proposed.

Antimicrobial activity of different disinfectants against cariogenic microorganisms.

The aim of this study was to assess the in vitro antimicrobial effects of chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHBM), and octenidine dihydrochloride (OCT) on cariogenic microorganisms by using their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). CHX, PHBM, and OCT were diluted in distilled water to the final test concentrations. Using the in-tube dilution method, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Actinomyces viscosus were cultivated on blood agar and Mueller-Hinton broth (MHB) at 37°C for 48 h. They were read using a spectrophotometer to detect MIC. To determine MBC, samples in the range of the turbidity threshold after 24 h were transferred onto blood agar and evaluated for growth after 24 h. Different MICs and MBCs were observed in all disinfectants against each microorganism. The lowest MIC and MBC against S. mutans (60 mg/L) were obtained from PHBM. The lowest values against L. rhamnosus (15 mg/L, 30 mg/L), A. viscosus (30 mg/L), and L. acidophilus (15 mg/L, 30 mg/L) were determined by OCT. PHBM and OCT have the potential to be replaced with CHX because they were effective against cariogenic microorganisms.

Antimicrobial activity of different disinfectants against cariogenic microorganisms

Abstract The aim of this study was to assess the in vitro antimicrobial effects of chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHBM), and octenidine dihydrochloride (OCT) on cariogenic microorganisms by using their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). CHX, PHBM, and OCT were diluted in distilled water to the final test concentrations. Using the in-tube dilution method, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Actinomyces viscosus were cultivated on blood agar and Mueller-Hinton broth (MHB) at 37°C for 48 h. They were read using a spectrophotometer to detect MIC. To determine MBC, samples in the range of the turbidity threshold after 24 h were transferred onto blood agar and evaluated for growth after 24 h. Different MICs and MBCs were observed in all disinfectants against each microorganism. The lowest MIC and MBC against S. mutans (60 mg/L) were obtained from PHBM. The lowest values against L. rhamnosus (15 mg/L, 30 mg/L), A. viscosus (30 mg/L), and L. acidophilus (15 mg/L, 30 mg/L) were determined by OCT. PHBM and OCT have the potential to be replaced with CHX because they were effective against cariogenic microorganisms.

Evaluation of the smear layer removal and erosive capacity of EDTA, boric acid, citric acid and desy clean solutions: an in vitro study.

BACKGROUND: The purpose of this study was to investigate the smear layer removal and erosive capacity of various irrigation solutions with sequential use of NaOCl on instrumented root canal walls. METHODS: The root canals of single-rooted teeth were instrumented with ProTaper rotary instrument. Then, the teeth were randomly divided into five experimental groups. The root canals were irrigated with one of the following solutions (5 mL/1 min): 5% EDTA, 5% boric acid (BA), a mixture of BA and CA, 2.5% citric acid (CA) and 5% Desy Clean. After irrigating with 2.5% NaOCl and distilled water, the roots were split into two halves and each half was prepared for SEM examination. Representative photographs were taken from each third at x500 and x1000 magnifications. Double blind scoring was performed by two calibrated observers for smear layer and erosion. The scores were statistically analyzed using Kruskal-Wallis, Dunn's post hoc and Spearman's correlation tests (p = 0.05). RESULTS: There were statistically significant differences among the solutions by means of smear layer and erosion (p < 0.05). While 2.5% CA solution was the most effective solution in removal of smear layer, it was also the most erosive solution (p < 0.05). 5% Desy Clean removed smear layer effectively and caused less erosion. There was a negative, but statistically significant correlation between presence of smear layer and erosion (r = -0.684; p < 0.0001). CONCLUSION: Desy Clean can be a promising agent as an irrigation solution with optimal smear layer removal capacity and less erosive effects.

Comparison of the cyclic fatigue resistance of 5 different rotary pathfinding instruments made of conventional nickel-titanium wire, M-wire, and controlled memory wire.

INTRODUCTION: This study compared the cyclic fatigue resistance of current nickel-titanium rotary path-finding instruments. METHODS: Five types of nickel-titanium rotary pathfinding instruments were used in steel canals with a 90° curvature and a curvature radius of 3 mm (n = 10) and 5 mm (n = 10). The cyclic fatigue of the following instruments was tested at 4 mm from the tip: PathFile (#16 and a .02 taper; Dentsply Maillefer, Ballaigues, Switzerland), G-File (#12 and a .03 taper; Micro-Mega, Besançon Cedex, France), Scout Race (#15 and a .02 taper; FKG Dentaire, La Chaux-de-Fonds, Switzerland), HyFlex GPF (#15 and a .02 taper; Coltene-Whaledent, Allstetten, Switzerland), and ProGlider (#16 with a mean taper of .04125 and a .02 at the first 4 mm from the tip, Dentsply Maillefer). The length of the fractured parts was measured, and the number of cycles to fracture (NCF) was calculated. The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (α = .05). After Bonferroni correction, the new P value was set as .005. RESULTS: The difference in the cyclic fatigue of all the files at both curvatures was statistically significant (P values from .0035 to less than .0001). The ranking of the instruments from the highest to the lowest NCF was as follows: HyFlex GPF, G files, ProGlider, PathFile, and Scout Race. The length of the fractured part of the instruments was similar in all the groups (P > .05). All the tested instruments had a lower NCF at a curvature radius of 3 mm when compared with a curvature radius of 5 mm (P < .0001). CONCLUSIONS: Within the limitations of this study, the cyclic fatigue resistance of the HyFlex GPF instrument was the highest, and the curvature radius had a significant effect on the fatigue resistance.

Effects of etching and adhesive applications on the bond strength between composite resin and glass-ionomer cements.

OBJECTIVE: This study determined the effects of various surface treatment modalities on the bond strength of composite resins to glass-ionomer cements. MATERIAL AND METHODS: Conventional (Ketac Molar Quick Applicap) or resin-modified (Photac Fil Quick Aplicap) glass-ionomer cements were prepared. Two-step etch-rinse & bond adhesive (Adper Single Bond 2) or single-step self-etching adhesive (Adper Prompt L-Pop) was applied to the set cements. In the etch-rinse & bond group, the sample surfaces were pre-treated as follows: (1) no etching, (2) 15 s of etching with 35% phosphoric acid, (3) 30 s of etching, and (4) 60 s of etching. Following the placement of the composite resin (Filtek Z250), the bond strength was measured in a universal testing machine and the data obtained were analyzed with the two-way analysis of variance (ANOVA) followed by the Tukey's HSD post hoc analysis (p=0.05). Then, the fractured surfaces were examined by scanning electron microscopy. RESULTS: The bond strength of the composite resin to the conventional glass-ionomer cement was significantly lower than that to the resin-modified glass-ionomer cement (p<0.001). No significant differences were determined between the self-etching and etch-rinse & bond adhesives at any etching time (p>0.05). However, a greater bond strength was obtained with 30 s of phosphoric acid application. CONCLUSIONS: The resin-modified glass-ionomer cement improved the bond strength of the composite resin to the glass-ionomer cement. Both etch-rinse & bond and self-etching adhesives may be used effectively in the lamination of glass-ionomer cements. However, an etching time of at least 30 s appears to be optimal.

Influence of fiber-reinforced composites on the resistance to fracture of vertically fractured and reattached fragments.

INTRODUCTION: The aim of this in vitro study was to evaluate the fracture type and test the effects of 2 different fibers on fracture strength of roots with reattached fragments. The null hypothesis was that adding suitable fibers to the content of dual-cure adhesive resin cement increases the fracture resistance of reattached fragments under vertical forces. METHODS: Root canals of 45 teeth were prepared, and the teeth were intentionally fractured into 2 separate fragments. Control groups (n = 7 each) consisted of unfractured teeth with instrumented and obturated or only instrumented root canals. The fractured teeth were divided into 3 groups (n = 15 each), and separated fragments were reattached by using (1) dual-cured resin cement (Clearfil SA), (2) dual-cured resin cement + polyethylene fiber (Construct), or (3) dual-cured resin cement + glass fiber (Stick-Net). Force was applied at a constant speed of 0.5 mm/min to the root until fracture. Mean load was recorded and analyzed statistically by using Kruskal-Wallis and Dunn tests (P = .05). Fracture types were analyzed by using χ(2) analysis with Yates correction. RESULTS: Stick-Net demonstrated the lowest fracture resistance (P < .05), whereas Construct and Clearfil SA had similar fracture strengths (P > .05). The roots in the control group showed the highest fracture resistance. However, there was no statistically significant difference between the Construct, Clearfil SA, and control groups (P > .05). CONCLUSIONS: Separated fragments of vertically fractured teeth can be reattached by using a dual-cured resin or by adding polyethylene fiber (Construct).

The influence of bonding agents on the decision to replace composite restorations.

UNLABELLED: This in vitro study evaluated the validity of the decision to replace of a restoration based upon the radiolucent zone beneath a resin composite. MATERIALS AND METHODS: Class II cavities were prepared on the approximal surfaces of 40 molars. The teeth were divided into four groups. Clearfil SE Bond, PQ1 or Single Bond was applied in the experimental groups. No bonding agent was used in the control group. Following the restorations, digital radiographs were obtained and independently evaluated by two oral radiologists and two specialists in restorative dentistry to determine the need for replacement. The coronal portions of the teeth were then sectioned and the interfaces between the restorations and cavity walls were examined using an optical light microscope. Possible adhesive pooling and voids were examined under a light microscope. Inter-examiner reliability was evaluated with the Cohen's kappa (kappa) test. Sensitivity, specificity and negative and positive predictive values were calculated. Kruskal-Wallis, followed by the Mann-Whitney U-test, determined differences among the pooling thicknesses of the different adhesives. RESULTS: Various sensitivity and specificity degrees were obtained from the groups in which different adhesive systems were used. The PQ1 adhesive system was the best for identifying well-adapted restorations with the highest true non-replacement diagnosis (TND = 0.70). Clearfil SE Bond had the highest false positive scores. Adhesive pooling was significantly different in the experimental groups of the current study (p < 0.05). CONCLUSION: Replacement decisions for a resin composite restoration based upon digital images frequently resulted in false-positive or negative decisions.

Preliminary evaluation of titanium tetrafluoride as an alternative ceramic etchant to hydrofluoric acid.

PURPOSE: The etching of dental ceramics with a glassy matrix by means of hydrofluoric acid (HF) is highly effective and after the application of a silane coupling agent, a strong link between the adhesive and the ceramic is achieved. The purpose of this study was to investigate whether aqueous titanium tetrafluoride (TiF4) solution could be used as an alternative ceramic etchant or not. MATERIALS AND METHODS: Seventy lithia-based all-ceramic specimens (IPS Empress 2, Ivoclar Vivadent) (diameter: 4 mm, height: 4 mm) were prepared and ultrasonically cleaned for 15 min in ethanol and deionized water, then divided into 1 control and 4 experimental groups (n = 14/group). The control group was acid etched with 4.9% HF for 20 s as described by the manufacturer. The experimental groups were treated with 2.5% TiF4 solution for 60 s, 2.5% TiF4 solution for 120 s and 5% TiF4 solution for 60 s, as well as 5% TiF4 solution for 120 s. Seven of the ceramic specimens in each group were luted to the other seven by a dual-curing cement (Variolink II, Ivoclar Vivadent,) with silane application (Monobond-S). After storage of luted specimens in deionized water at 37 degrees C for 24 h, the specimens were embedded in plastic holders with cyanoacrylate, and the shear-bond strength (SBS) tests were performed with a Shimadzu universal testing machine at a crosshead speed of 0.5 mm/min. A one-way ANOVA and Bonferroni correction, followed by the Tukey test, were applied for statistical analysis. Scanning electron microscopic examination was performed to evaluate the pattern of debonding. RESULTS: Significantly higher SBS values (p 0.05). CONCLUSION: Aqueous TiF4 solution exhibited similar shear bond strength values in comparison to commonly used HF and can be considered as an alternative ceramic etchant within the limitations of this preliminary report.

The effect of different concentrations of EDTA on instrumented root canal walls.

OBJECTIVE: The purpose of this study was to investigate smear layer removal and erosive capacity of different concentrations of EDTA on instrumented root canal walls. STUDY DESIGN: Forty single-rooted teeth were instrumented using step-back technique and 2.5% NaOCl. The teeth were randomly divided into 4 groups, and final flushes were preformed with different concentrations of EDTA (15%, 10%, 5%, and 1%). All specimens were prepared for scanning electron microscope evaluation. RESULTS: The results showed that there was no significant difference on the smear layer removal between different concentrations of EDTA (P = .1959). Only coronal versus apical thirds showed significant difference regarding presence of smear layer (P = .0176). Whereas 15%, 10%, and 5% EDTA solutions demonstrated similar erosion patterns on the root canal walls (P > .05), 1% EDTA caused restricted erosion (P < .0001). There was no significant difference among the regions in terms of erosion (P = .6399). CONCLUSION: Lower concentrations of EDTA can be recommended for clinical usage to avoid excessive erosion of root canal dentin.

In vitro antimicrobial activity of calcium hydroxide mixed with different vehicles against Enterococcus faecalis and Candida albicans.

OBJECTIVE: The purpose of this in vitro study was to investigate antimicrobial activity of calcium hydroxide (CH) in combination with glycerin, chlorhexidine gluconate (CHX), cetrimide, or distilled water against Enterococcus faecalis and Candida albicans. STUDY DESIGN: Standard holes in the cultivated agar plates were filled with one of the CH preparations and control agents. The zones of microbial inhibition were measured after incubation period. RESULTS: The CH preparations with glycerin and CHX demonstrated more antifungal activity than CH preparations with cetrimide and distilled water. The CH-glycerin preparations had no effect against E. faecalis, and CH-CHX preparation was the most effective medication. CONCLUSION: Antimicrobial activity of CH may change with the type of the vehicle and against different microorganisms. Enterococcus faecalis was more resistant than C. albicans to CH preparations.

The effect of treatment of radicular dentin on colonization patterns of C. albicans.

OBJECTIVE: The aim of this study was to observe the colonization pattern of C. albicans on treated and untreated radicular dentin. STUDY DESIGN: Root sections of 10 human mandibular premolar teeth were longitudinally separated into halves. The 20 halves were separated into 2 groups and each half served as its own control. In Group 1, only gross pulpal remnants were removed with pliers. Root canal walls in the corresponding 102 halves (Group 2) were instrumented with Gates-Glidden burs and treated with sequential use of 15% EDTA solution for 3 minutes and 2.5% NaOCl solution for 3 minutes. Finally, all teeth were washed with distilled water. Each specimen was placed individually in each well of a 24-well cell culture plate. After the assembly was sterilized with ethylene-oxide, the root canal of each specimen was inoculated with 20 microL of C. albicans (1-1.5 x 10(6) cfu/mL) that was kept in place for 24 hours for initial attachment. Then, 2 mL of SDB was added to each well and the assembly was placed in an incubator at 37 degrees C for 10 days. Following the incubation period, the specimens were washed, fixed, dehydrated, and processed for scanning electron microscopy. RESULTS: C. albicans was present on the root canal surfaces of all specimens; however, the colonization pattern was different. In the untreated group, the main growth pattern was a dense mass of yeast cells forming biofilm layers while hyphal structures were not common. On the other hand, pseudohyphae invaded all root canal surfaces in Group 2 and yeast cells were occasionally observed. CONCLUSION: The treatment procedures of root canal dentin have a strong influence on the colonization pattern of C. albicans. This fact should be considered when planning and evaluating in vitro Candida adhesion and/or penetration studies.

Idiopathic root resorption of the entire permanent dentition: systematic review and report of a case.

A rare case of idiopathic root resorption affecting the entire dentition was described. Root resorptions of all of the maxillary and mandibular teeth were coincidentally diagnosed on patient's radiographic examination. The patient's medical and dental findings were non-contributory, other than the increased mobility of upper incisors. No significant familial findings could be identified. Detailed radiographic examination revealed resorption affecting the apical part of the roots, resulting in vertical shortening of the teeth. The character of the resorption was as if a tapering occurred throughout the lateral root surfaces. Involved teeth were endodontically treated and the patient was subsequently followed-up for 18 months. Following endodontic therapy, all periapical lesions demonstrated clinical and radiographic evidence of healing. Endodontic therapy resulted in a high degree of success to stop resorption process and maintain the dentition.

Effect of various digital processing algorithms on the measurement accuracy of endodontic file length.

OBJECTIVE: The aim of this study was to compare the accuracy of endodontic file lengths after application of various image enhancement modalities. STUDY DESIGN: Endodontic files of three different ISO sizes were inserted in 20 single-rooted extracted permanent mandibular premolar teeth and standardized images were obtained. Original digital images were then enhanced using five processing algorithms. Six evaluators measured the length of each file on each image. The measurements from each processing algorithm and each file size were compared using repeated measures ANOVA and Bonferroni tests (P = 0.05). Paired t test was performed to compare the measurements with the true lengths of the files (P = 0.05). RESULTS: All of the processing algorithms provided significantly shorter measurements than the true length of each file size (P < 0.05). The threshold enhancement modality produced significantly higher mean error values (P < 0.05), while there was no significant difference among the other enhancement modalities (P > 0.05). Decrease in mean error value was observed with increasing file size (P < 0.05). CONCLUSIONS: Invert, contrast/brightness and edge enhancement algorithms may be recommended for accurate file length measurements when utilizing storage phosphor plates.

The effect of three different sealers on the radiopacity of root fillings in simulated canals.

OBJECTIVE: The aim of this study was to investigate the effect of 3 root canal sealers on radiopacity of root fillings in simulated canals by means of direct digital radiography. STUDY DESIGN: Thirty simulated root canals in transparent acrylic blocks were prepared with a 4% tapered, size 25 instrument. A single 4% tapered, size 25 gutta-percha cone was inserted into each canal. Standardized images of the blocks with an aluminum step-wedge were obtained by using Digora storage phosphor plates. Then, 3 root canal sealers (Roeko, Diaket, Pulpdent) were mixed according to the manufacturers' instructions. The gutta-percha cones were completely coated with one of the sealers and placed in the identical canal to the full working length. The images of the blocks were reobtained after sealer application. The mean gray values (MGVs) of root fillings were measured with or without the sealer at 3 different levels (1 mm, 6 mm, and 11 mm from apex) by using the Image Tool program. Each MGV measurement was then converted to its aluminum equivalent by means of the step-wedge values. A paired t test was used for statistical analysis. RESULTS: RoekoSeal caused a significant decrease in the radiopacity of the root fillings at the 1-mm level (P < 0.01). Diaket and Pulp Canal Sealer (PCS) increased the radiopacity of the fillings at all levels significantly (P < 0.01) except 6- and 11-mm levels of the Diaket specimens (P > 0.05). CONCLUSION: The type and the thickness of root canal sealers can influence the radiopacity of the root fillings.

Ultrastructural stages of biofilm development of Escherichia coli on urethral catheters and effects of antibiotics on biofilm formation.

OBJECTIVES: Biofilm formation on biomaterials by various kinds of bacteria renders the infection chronic, and the bacteria can become resistant to the immune system and antibiotics. Developmental biofilm stages of Escherichia coli on urethral catheters have not yet been thoroughly demonstrated. We aimed to show biofilm formation of E. coli on urethral catheters, and the effects of various antibacterial agents on this formation using scanning electron microscopy. METHODS: Using urine infected with uropathogenic E. coli type O4 (10(5) to 10(6) colony forming units/mL), biofilm was formed on latex/silicone balloon catheters in a modified Robbin's device. The study included an infected-only group and four antibiotic study groups (ciprofloxacin, cefuroxime, gentamicin, and trimethoprim). The catheters were infused with the antibiotic solutions once before placement in the modified Robbin's devices. Ten 5-mm catheter samples were taken for all groups on the first, fourth, and seventh days. The 4 and 12-hour and 2-day samplings were also taken from the infected-only group. The catheter samples were evaluated by scanning electron microscopy and given scores according to the level of formation. RESULTS: The biofilm layers emerged between 4 and 12 hours after infection in the infected-only group and had developed completely between 12 and 24 hours. The antibiotics, especially cefuroxime, significantly delayed this process for up to 4 days. However, the biofilm had developed completely in almost all catheter samples after 4 to 7 days. CONCLUSIONS: Biofilm of E. coli on urethral catheters had completed their maturation at 12 to 24 hours. For short-term urethral catheterization, a single dose of antibiotic can delay the development of biofilm for up to 4 days but eventually cannot prevent it.

Bacterial microleakage of barrier materials in obturated root canals.

The bacterial microleakage of four current restorative materials (glass ionomer cement, polycarboxylate cement, resin modified glass ionomer cement, and flowable composite resin) used as a base over obturated root canals were evaluated during a 5-month period. Sixty single-rooted mandibular premolars were obturated with cold lateral compaction of gutta-percha. The teeth were randomly divided into five groups of 10 teeth each and positive and negative control groups of five. The access openings were filled with one of the tested barrier materials in four groups. In group 5, no barrier material was placed. Samples were incorporated in a model system using Staphylococcus epidermidis as a microbial marker. Results were analyzed with Kaplan-Meier survival analysis (p = 0.05). The sealing ability of all tested materials was better when compared with group 5 (no barrier material) (p < 0.05). Within the limitations of this study, the glass ionomer cement leaked significantly less when compared with the flowable composite resin (p < 0.05).

Comparison of the hardness and microbiologic adherence of four permanent denture soft liners.

Resilient denture linings cannot be used for extended periods due to the loss of softness and the adhesion of microorganisms on their surfaces. This study investigated the hardness and microbiologic adherence of four permanent soft denture lining materials. In addition, the adherence of Candida albicans and Staphylococcus aureus was studied in vitro by quantitative culture method and scanning electron microscopy (SEM). Surface properties of the materials also were observed with SEM. The hardness of all materials increased throughout the study. Molloplast-B was the most adequate permanent soft lining material for clinical use under these laboratory conditions.

The effect of calcium chelating or binding agents on Candida albicans.

OBJECTIVE: The aim of this study was to evaluate antifungal effects of calcium-chelating or -binding agents on Candida albicans comparing with conventional antifungal agents. STUDY DESIGN: Two clinical oral isolates and 1 standard strain of C albicans were included in the study. Test solutions were ethylenediamine-tetraacetic acid (EDTA), ethyleneglycol-tetraacetic acid (EGTA), sodium fluoride (NaF), titanium tetrafluoride (TiF4), nystatin, and ketoconazole. Minimum inhibitory and fungicidal concentrations of the solutions were determined. The results were analyzed statistically using Friedman's nonparametric 2-way ANOVA and Mann-Whitney U tests. RESULTS: All isolates demonstrated similar susceptibility patterns (P>.05). Except ketoconazole, EDTA had the highest antifungal and fungicidal activity, followed by TiF4. EGTA and NaF were the weakest agents against C albicans among all test solutions. CONCLUSION: EDTA and TiF4 may be recommended as an alternative irrigating solution particularly in persistent root canal infections and in root canals of patients having a high incidence of oral candidosis.

Mechanical and fluoride release properties of titanium tetrafluoride-added glass-ionomer cement.

The aim of this study was to determine the fluoride-release and mechanical properties of a water-hardening glass-ionomer cement (GIC) (ChemFil Superior) when titanium tetrafluoride (TiF4) was added. Three experimental groups were prepared with TiF4 added to the liquid component of the material in concentrations of 0.5, 1, and 2%. The control group was the original form of the cement and free of TiF4. After the specimens (4 mm in diameter x 6 mm in length) were prepared, their compressive strength, microhardness, modulus of elasticity, and fluoride release were measured. Data were analyzed using one-way analysis of variance (ANOVA) and post-hoc test (Bonferroni/Dunn correction). The addition of TiF4 into GIC significantly reduced fluoride release from the material with the exception of 1% TiF4 (p < 0.0083). Compressive strengths of 0.5 and 1% TiF4-added GICs were higher than that of the original GIC, but it was not statistically significant (p > 0.05). The differences among modulus of elasticity values of experimental and control groups were not significant (p > 0.05). Similarly, microhardness of GIC was not affected with TiF4 addition (p > 0.05).