Effects of dyes used in photodynamic therapy on color stability of composite resins.

PURPOSE: The aim of this study was to evaluate the effect of dyes used in photodynamic therapy (PDT) on color changes of resin-based composites (RBCs). METHODS: A total of 120 composite discs were made of microfilled, nanohybrid, and nanoceramic RBCs, and the CIE Lab system was used to assess initial colors with a spectrophotometer. Photosensitizers were used in accordance with the experimental design, as follows: MB (methylene blue), TB (toluidine blue), ICG (indocyanine green), and control (no dye). The samples were irradiated with a 940-nm diode laser. After irradiation, the photosensitizers were removed with distilled water (∆E1) and sodium hypochlorite (∆E2), and final colors were measured. Data were analyzed by the three-way ANOVA and Bonferroni tests (α = 0.05). RESULTS: There was no statistically significant difference between the ICG and control groups; however, the TB and MB groups exhibited the strongest staining. The nanohybrid RBC exhibited the greatest color change, and there were no significant differences between the microhybrid and nanoceramic RBCs. After NaOCl irrigation, ΔE2 values decreased to clinically acceptable values (ΔE2 < 3.3). CONCLUSION: The intensity of staining of the RBCs differed according to the type of photosensitizer used and the content of the composite resin. The irrigant NaOCl was effective in removing discoloration.

The effect of different chelators on the dislodgement resistance of MTA Repair HP, MTA Angelus, and MTA Flow.

The aim of this study was to investigate the influence of various irrigants on the dislodgement resistance of MTA Repair HP, MTA Angelus, and MTA Flow to root dentin. Three slices (1.0 ± 0.1 mm) were prepared from the middle third of 20 human maxillary anterior teeth. On each dentin disc, three perpendicular simulated perforation holes with a standardized 0.8 mm diameter were created. The sections from the same root were distributed arbitrarily into three groups (n = 20) for smear layer removal procedure: ethylenediaminetetraacetic acid (EDTA), chitosan-based silver nanoparticles (AgNPs-chitosan), and maleic acid (MA). Afterwards, the holes were randomly filled with one of the three investigated cements. The samples were submitted to the push-out test using a universal measuring system. Kruskal-Wallis and Mann-Whitney U tests were used to assess statistical differences among the groups. When the results were evaluated, it was found that the types of cement and chelating agents significantly affected the dislocation resistance (P < 0.05). EDTA provided a higher dislocation resistance with the investigated cements in comparison to MA and AgNPs-chitosan (P < 0.05). Furthermore, it was observed that MTA Flow and MTA Angelus presented improved dislocation resistance values than the MTA Repair HP when used with EDTA (P < 0.05). The findings indicated that EDTA increased the dislodgement resistance of the investigated cements. In conclusion, when EDTA used, MTA Flow, and MTA Angelus showed higher dislocation resistance values.

Effect of different chelating agents and their surface tension on the amount of apically extruded debris.

BACKGROUND/PURPOSE: During root canal preparation apical extrusion is an undesirable situation that can cause postoperative complications. The aim of the present study is to evaluate the effect of the presence of different chelators in root canals during preparation on the amount of apically extruded debris and to investigate the effect of surface tension of irrigant on the apical extrusion. MATERIALS AND METHODS: Ninety extracted mandibular incisor teeth were included. Prior to canal preparation, the teeth were mounted to Eppendorf tubes. Root canals of the samples were prepared with Reciproc instruments in the presence of different chelating agents (17% EDTA-liquid, 17% EDTA-gel, 7% maleic acid, 2.25% peracetic acid, 10% citric acid) and 5% NaOCl. Apically extruded debris was collected in Eppendorf tubes and weighted with an electronic balance. The surface tension of solutions was calculated with the ring method using a du Noüy ring digital tensiometer. The statistical analysis was performed with Tamhane's T2 test for apical extrusion and the Tukey for surface tension. The correlation between apical extrusion and surface tension was compared using Pearson's coefficient. RESULTS: The least amount of apically extruded debris was with EDTA-gel, peracetic acid and citric acid which were similar to each other. NaOCl had the highest surface tension whereas peracetic acid and EDTA-liquid had the lowest. There was no significant correlation exists between apical extrusion and surface tension. CONCLUSION: The presence of EDTA-gel, citric acid and peracetic acid in root canals during preparation decreased the amount of apically extruded debris compared to other solutions. The investigated irrigation solutions have no significant effect on the amount of apical debris extrusion.

The assessment of different bleaching agents' efficiency on discoloured teeth using image-processing methods.

BACKGROUND: Although triple antibiotic paste (TAP) has been successfully used as an intracanal medicament for regenerative endodontic treatments, TAP has also been shown to cause discolouration. The aim of this study is to investigate the efficacy of different bleaching agents to bleach teeth discoloured from TAP. METHODS: Two hundred extracted human maxillary incisors were evaluated with VITA Easyshade, and 120 teeth were prepared and discoloured by using TAP for three weeks. After colouration, 70 teeth were randomly divided into five groups: Group 1: Negative control, Group 2: Sodium perborate, Group 3: Opalescence Endo, Group 4: Endoperox, and Group 5: Biolase. The colour changes in the third and seventh days' standard images were obtained using stereomicroscopy, RGB and Lab color space transformations were applied to the images. The CIE Lab color system was used, and total color changes (ΔE) were calculated and compared among groups and over time, using analysis of variance testing. RESULTS: At the third day, there was no difference between bleaching materials. At the seventh day, the Biolase group was superior to sodium perborate and there was no difference between other groups. A statistically significant difference was noted between the third and seventh-day measurements for all bleaching protocols. Bleaching effectiveness of all agents increased over time. CONCLUSIONS: Teeth discoloured by using TAP may be bleached by means of the investigated protocols, and colour alteration can be increased over time. The CIE Lab colour system can be used as an alternative, in vitro test for evaluating the bleaching efficiency of bleaching agents.

Effect of different chelating agents on the bond strength of a silicone-based root canal sealer to root dentin.

AIM: The purpose of this study was to evaluate the impact of 7% maleic acid (MA), 17% ethylenediaminetetraacetic acid (EDTA) solution, 10% citric acid (CA), or 2.25% peracetic acid (PAA) on the dislodgment resistance of a silicone-based root canal sealer. MATERIALS AND METHODS: Ninety-five mandibular incisors were shaped to size R50. The specimens were randomly assigned to the following five groups (n = 15) based on the final irrigation solution: 5% sodium hypochlorite (NaOCl), 17% EDTA, 7% MA, 10% CA, and 2.25% PAA. Four specimens from each group were examined under scanning electron microscope. All the remaining canals were obturated with GuttaFlow® Bioseal. Bond strength was assessed using the push-out test. The data were analyzed statistically by two-way analysis of variance and Bonferroni tests at the significance level of P = 0.05. RESULTS: The roots irrigated with chelators showed statistically significantly higher bond strength than the roots irrigated with NaOCl (P < 0.05). Overall, MA showed the highest bond strength, but there was no statistically significant difference among the other chelating solutions (P > 0.05). CONCLUSIONS: The bond strength of the GuttaFlow Bioseal to the root canal dentin may increase by the removal of smear layer. Final irrigation with the investigated chelators resulted in similar bond strength of the GuttaFlow Bioseal.

Effect of different chelating agents on dentinal crack formation.

The present study aimed to evaluate the degree of crack formation during canal preparation using reciprocating files. A total of 120 incisor teeth were divided into eight groups according to irrigation protocol (n = 15). The irrigation solution and chelating agents included distilled water, sodium hypochlorite (NaOCl), citric acid, maleic acid, peracetic acid, ethylenediaminetetraacetic acid (EDTA) gel, and EDTA liquid. The root canals were prepared using reciprocating instruments while one of the agents was present within the root canals. A control group was subjected to neither preparation nor irrigation. The roots were horizontally sectioned 3, 6, and 9 mm away from the apices. The numbers of cracks were recorded. Statistical analyses were performed using a chi-squared test. The chelating agents resulted in similar numbers of cracked sections. The use of one of the chelating agents during preparation using reciprocating instruments appears to be beneficial in reducing crack formation.

Effects of photodynamic therapy with indocyanine green on Streptococcus mutans biofilm.

BACKGROUND: The current procedures for treating tooth decay are not always guaranteed to successfully remove all microorganisms which cause disease. For elimination of bacteria and prevention of their effects, different methods are recommended, such as antibacterial materials and cavity disinfectants. The aim of this study was to compare the antibacterial activity of photodynamic therapy (PDT) using diode laser with indocyanin green (ICG) on Streptococcus (S.) mutans biofilm with conventional methods. METHODS: Ninety human molars were divided into 9 groups: negative control, positive control, CHX, NaOCl, gaseous ozone, erbium (Er):YAG laser, diode laser, and indocyanin green/ICG, and PDT. Cavities were then cut into the teeth (2 per tooth, 20 cavities per group) and sterilized. For all of the groups, with the exception of the negative control group, 105 CFU/mL of the active S. mutans culture were inoculated into the cavities and then incubated at 37 °C for 72 h. Then, dentin chips (25 ± 5 mg) were collected from cavity walls and spread on Mueller-Hinton agar media after decimal dilution. The colonies were counted after incubation at 37 °C for 24 h. RESULTS: All the treatments significantly reduced the number of S. mutans compared with the positive control group (p < 0.05). The antimicrobial effectiveness of CHX, NaOCl, ozone, PDT, Er:YAG laser, and diode laser groups were similar. The lowest bacterial reduction was observed in the ICGgroup. CONCLUSIONS: This work concludes that PDT using diode laser with ICG may be suggested on the cavity disinfection after caries excavation as an alternative to conventional methods.

Evaluation of the dislodgement resistance of bioceramic reparative cements placed in a retrograde cavity using a different technique

Aim: Calcium silicate-based fillings have been widely used in surgical endodontic treatment because of hard-tissue conductive and inductive properties. The aim of present study is to investigate the bond strength of different calcium silicate-based fillings in retrograde cavities. Methods: Forty-four maxillary single rooted teeth were endodontically treated. The apical portions of the teeth were removed and root-end cavities were prepared using an ultrasonic tip. The roots were randomly divided into four experimental groups (n = 11) according to the material used; (1) MTA-FILLAPEX, (2) MTA Repair HP, (3) MTA-FILLAPEX+ MTA Repair HP, and (4) MTA Plus. Two horizontal cross sections (1±0.1 mm thick) from each specimen were resected from the apices. These sections were placed in a universal testing machine to evaluate the push-out bond strength force required for dislodgement of the root end filling was recorded. The failure type was also evaluated by using a stereomicroscope. The differences in bond strength were analyzed using the two-way analysis of variance (ANOVA). Results: MTA-FILLAPEX and MTA Plus displayed the lowest and highest dislocation resistance, respectively (P < 0.05). In the apical level, bond strength was significantly higher than the coronal level in all groups except for MTA-FILLAPEX. Mixed failure was prevalent in all groups, except for MTA-FILLAPEX, which showed purely cohesive failures. Conclusions: Investigated calcium silicate-based filling materials showed different bond strength to the root-end cavity. The bond strength was significantly decreased when the prior application of MTA-FILLAPEX before delivery of MTA Repair HP

Effectiveness of various irrigation protocols for the removal of calcium hydroxide from artificial standardized grooves.

OBJECTIVE: The aim of this study was to investigate the ability of laser-activated irrigation (LAI), XP-endo Finisher, CanalBrush, Vibringe, passive ultrasonic irrigation (PUI), and conventional syringe irrigation systems on the removal of calcium hydroxide (CH) from simulated root canal irregularities. MATERIAL AND METHODS: The root canals of one hundred and five extracted single-rooted teeth were instrumented using Reciproc rotary files up to size R40. The teeth were split longitudinally. Two of the three standard grooves were created in the coronal and apical section of one segment, and another in the middle part of the second segment. The standardized grooves were filled with CH and the root halves were reassembled. After 14 days, the specimens were randomly divided into 7 experimental groups (n=15/group). CH was removed as follows: Group 1: beveled needle irrigation; Group 2: double side-vented needle irrigation; Group 3: CanalBrush; Group 4: XP-endo Finisher; Group 5: Vibringe; Group 6: PUI; Group 7: LAI. The amount of remaining CH in the grooves was scored under a stereomicroscope at 20× magnification. Statistical evaluation was performed using Kruskal-Wallis and Bonferroni-Correction Mann-Whitney U tests. RESULTS: Groups 1 and 2 were the least efficient in eliminating CH from the grooves. Groups 6 and 7 eliminated more CH than the other protocols; however, no significant differences were found between these two groups (P>.05). CONCLUSIONS: Nevertheless, none of the investigated protocols were able to completely remove all CH from all three root regions. LAI and PUI showed less residual CH than the other protocols from artificial grooves.

Effectiveness of various irrigation protocols for the removal of calcium hydroxide from artificial standardized grooves

Abstract Objective The aim of this study was to investigate the ability of laser-activated irrigation (LAI), XP-endo Finisher, CanalBrush, Vibringe, passive ultrasonic irrigation (PUI), and conventional syringe irrigation systems on the removal of calcium hydroxide (CH) from simulated root canal irregularities. Material and Methods The root canals of one hundred and five extracted single-rooted teeth were instrumented using Reciproc rotary files up to size R40. The teeth were split longitudinally. Two of the three standard grooves were created in the coronal and apical section of one segment, and another in the middle part of the second segment. The standardized grooves were filled with CH and the root halves were reassembled. After 14 days, the specimens were randomly divided into 7 experimental groups (n=15/group). CH was removed as follows: Group 1: beveled needle irrigation; Group 2: double side-vented needle irrigation; Group 3: CanalBrush; Group 4: XP-endo Finisher; Group 5: Vibringe; Group 6: PUI; Group 7: LAI. The amount of remaining CH in the grooves was scored under a stereomicroscope at 20× magnification. Statistical evaluation was performed using Kruskal-Wallis and Bonferroni-Correction Mann-Whitney U tests. Results Groups 1 and 2 were the least efficient in eliminating CH from the grooves. Groups 6 and 7 eliminated more CH than the other protocols; however, no significant differences were found between these two groups (P>.05). Conclusions Nevertheless, none of the investigated protocols were able to completely remove all CH from all three root regions. LAI and PUI showed less residual CH than the other protocols from artificial grooves.

An in vitro evaluation of various irrigation techniques for the removal of double antibiotic paste from root canal surfaces

ABSTRACT Objective The aim of this study was to investigate the effectiveness of conventional syringe irrigations, passive ultrasonic irrigation (PUI), Vibringe, CanalBrush, XP-endo Finisher, and laser-activated irrigation (LAI) systems in removing double antibiotic paste (DAP) from root canals. Material and Methods One hundred five extracted single-rooted teeth were instrumented. The roots were split longitudinally. Three standard grooves were created and covered with DAP. The roots were distributed into seven groups: Group 1, beveled needle irrigation; Group 2, double side-vented needle irrigation; Group 3, CanalBrush; Group 4, XP-endo Finisher; Group 5, Vibringe; Group 6, PUI; Group 7, LAI. The amount of remaining DAP was scored under a stereomicroscope. Results Group 4, Group 6, and Group 7 removed significantly more DAP than the other protocols in the coronal region. Group 7 was more efficient in the middle region; however, no significant difference was found between Group 7 and Group 6. No differences were found between groups in the apical region either, except for the comparisons between groups 7 and 2, and groups 2 and 3. Conclusions None of the investigated protocols were able to completely remove the DAP from the grooves. The Vibringe and XP-endo Finisher systems showed results similar to those of conventional needle irrigation.

An in vitro evaluation of various irrigation techniques for the removal of double antibiotic paste from root canal surfaces.

OBJECTIVE: The aim of this study was to investigate the effectiveness of conventional syringe irrigations, passive ultrasonic irrigation (PUI), Vibringe, CanalBrush, XP-endo Finisher, and laser-activated irrigation (LAI) systems in removing double antibiotic paste (DAP) from root canals. MATERIAL AND METHODS: One hundred five extracted single-rooted teeth were instrumented. The roots were split longitudinally. Three standard grooves were created and covered with DAP. The roots were distributed into seven groups: Group 1, beveled needle irrigation; Group 2, double side-vented needle irrigation; Group 3, CanalBrush; Group 4, XP-endo Finisher; Group 5, Vibringe; Group 6, PUI; Group 7, LAI. The amount of remaining DAP was scored under a stereomicroscope. RESULTS: Group 4, Group 6, and Group 7 removed significantly more DAP than the other protocols in the coronal region. Group 7 was more efficient in the middle region; however, no significant difference was found between Group 7 and Group 6. No differences were found between groups in the apical region either, except for the comparisons between groups 7 and 2, and groups 2 and 3. CONCLUSIONS: None of the investigated protocols were able to completely remove the DAP from the grooves. The Vibringe and XP-endo Finisher systems showed results similar to those of conventional needle irrigation.

Evaluation of Effects on the Adhesion of Various Root Canal Sealers after Er:YAG Laser and Irrigants Are Used on the Dentin Surface.

INTRODUCTION: The aim of this study was to evaluate the bond strength of various root canal sealers after various irrigation solutions and Er:YAG laser irradiation were used on root canal dentin. METHODS: One hundred fifty freshly extracted human maxillary single-rooted teeth were used in this study. Teeth were sectioned transversally 4 mm below the cementoenamel junction. The root canal of each specimen was prepared using a tapered bur. Teeth were divided into 3 main groups by sealer (AH Plus Jet [Dentsply DeTrey, Konstanz, Germany], EndoSequence BC Sealer [Brasseler, Savannah, GA], and Real Seal [SybronEndo, Orange, CA]) and then divided into 5 subgroups by dentin treatment (distilled water, calcium hydroxide, sodium hypochlorite, EDTA, and Er:YAG laser). The specimens were placed immediately at 37°C and 100% humidity for 1 week. Then, the push-out test was applied. The maximum failure load was recorded in newtons and was used to calculate the push-out bond strength in MPa. Then, 3 random specimens from each group were examined under scanning electron microscopy. RESULTS: The resin root canal sealers had higher push-out bond strength than the bioceramic sealer, and the differences were statistically significant (P < .05) except in the sodium hypochlorite groups. The EDTA and Er:YAG laser applications removed the smear layer and increased the bond strength. The highest adhesion was observed in EDTA groups when each sealer was evaluated in itself. CONCLUSIONS: The bonding strength of root canal sealers is influenced by their properties and various dentin surface treatments. The scanning electron microscopic study showed that although the dentinal tubules were open, at the profile examination the sealers did not penetrate into the dentin canals in all specimens.

In vitro evaluation of temperature rise during different post space preparations.

OBJECTIVE: The aim of this study was to evaluate temperature alterations on the outer root surface during post space preparation with six different post drills by using an infrared thermometer. MATERIALS AND METHODS: Sixty extracted single-rooted human mandibular incisor teeth were used. After root canal obturation, the specimens were divided into six groups (n = 10). During post space preparation, the temperature rises were measured in the middle third of the roots using a noncontact infrared thermometer with a sensitivity of 0.1°C. The temperature data were transferred from the thermometer to the computer and were observed graphically. RESULTS: The maximum temperature rise was observed in Snowpost 2 (29.95 ± 10.2°C) (P < 0.001), but there were no significant differences among Snowpost 2 (29.95 ± 10.2°C), Snowpost 1 (24.6 ± 8.0°C), and Relyx 2 (17.68 ± 9.1°C) (P > 0.05). CONCLUSIONS: Although water coolant used, the critical temperature rise was observed on the outer root surface in all post drill systems.