Search

Objectives: This study assessed the effects of blue and Er:YAG lasers, fluoride varnish, and their combination on microhardness, and calcium and phosphorus content of demineralized enamel. Materials and Methods: The primary Vickers microhardness of 28 third molars was measured and their enamel calcium and phosphorous content was quantified by energy-dispersive X-ray spectroscopy. They were then randomly assigned to five groups of 5% sodium fluoride (NaF) varnish, 445nm blue laser, Er:YAG laser, 5% NaF + 445nm blue laser, and 5% NaF + Er:YAG laser. The teeth then underwent pHcycling to induce caries-like lesions. The surface microhardness of the teeth and the calcium and phosphorous content of demineralized enamel were measured again. Data were analyzed by one-way ANOVA and Tukey's test (alpha=0.05). Results: NaF, NaF-diode laser, and NaF-Er:YAG laser groups experienced a significant increase in microhardness of demineralized enamel close to the baseline value (P<0.05). The efficacy of NaF-blue laser and NaF-Er:YAG laser was higher than NaF. In blue and Er:YAG laser groups, the mean final microhardness was significantly lower than the baseline microhardness. The percentage of phosphorus in all groups was similar to that of sound enamel. The percentage of calcium in NaF group was significantly lower than that of sound enamel and all other groups. The calcium content in other groups was similar to that of sound enamel. Conclusion: Fluoride varnish had a synergistic effect with Er:YAG and blue lasers to increase the demineralized enamel microhardness; blue and Er:YAG lasers alone were less effective. [ABSTRACT FROM AUTHOR]

Background: High levels of stress and fear of COVID-19 infection in high-risk places negatively affect visiting hygiene professionals and receiving health services including dentistry. This study was conducted with the aim to determine the impact of COVID-19 induced anxiety and Oral Health Literacy (OHL) on dental services during COVID-19 pandemic in the general population in Iran. Methods: This online cross-sectional study was performed on 307 individuals (244 women and 63 men) using convenient sampling method, at the time of COVID-19 outbreak (October and November 2021) in Tehran city. A demographic characteristics form, the COVID-19 Induced Anxiety Scale (CIAS) (Riad et al., 2021), and the Oral Health Literacy Questionnaire (OHLQ) (Naghibi Sistani et al., 2013) were used to collect data with items related to the rate and reasons for visiting/not visiting dentists. Data were analyzed using ANOVA and Pearson correlation test in SPSS software. Results: The results revealed no significant differences between those who had and those who had not had dental visits in terms of COVID-19 induced anxiety (P > 0.05). However, there was a significant difference between the two groups in terms of OHL (P < 0.05). In addition, no significant correlation was found between OHL and COVID-19 anxiety (P > 0.05). Conclusion: Notwithstanding the risk of Corona virus transmission in offices/clinics, higher levels of OHL caused more desire to use dentistry services in the public. [ABSTRACT FROM AUTHOR]

Background: Despite the improvements in optical properties of composite resins, their color stability is still a matter of concern. This study aimed to assess the curing time and intensity and polishing technique on color stability of bleach shade composite resins. Materials and Methods: In this in vitro, experimental study, 128 discs (1 mm x 8 mm) were fabricated from two composite resins. The specimens fabricated from each composite were assigned to 8 subgroups (n = 8) based on the curing time and intensity and polishing with polishing points or discs. After polishing, the color parameters of specimens were measured by EasyShade spectrophotometer according to the CIEL* a*b* color system. The specimens were then immersed in tea solution, and their color parameters were measured again. Color change (ΔE) was calculated and analyzed at 0.05 level of significance. SPSS 25 was used for data analysis. Univariate four way ANOVA was applied to assess the effects of composite type, curing time, curing intensity, and technique of polishing on ΔE of composite resins. Since the interaction effects were significant, subgroup analysis was performed by t-test. The level of significance for this test was set at 0.05. Results: The effects of curing intensity and polishing technique were significant on ΔE (P < 0.05). Filtek Z350 XBW composite specimens polished by polishing points experienced lower color change than those polished with discs. The minimum ΔE of Gradia XBW composite was recorded in specimens that underwent high intensity curing for 20 s and were polished with polishing points while the maximum ΔE was recorded in specimens that underwent high intensity curing for 20 s and were polished with discs. Conclusion: In all groups except on (Filtek, polishing with Disk, curing time = 20 s), high intensity curing and polishing with polishing points were more effective and caused lower color change compared with low-intensity curing and polishing with discs. [ABSTRACT FROM AUTHOR]

The aim of this in vitro study was to compare the efficacy and durability of bleaching with diode lasers over a 9-month period. This study evaluated 27 extracted teeth categorized into 3 bleaching groups (n = 9): 940-nm diode laser, 980-nm diode laser, and 40% hydrogen peroxide whitening gel (control). After the baseline color of the teeth was measured using a spectrophotometer, the teeth underwent dental prophylaxis and their color was measured again. Bleaching treatment was then performed. The color of the teeth was measured Immediately after bleaching and 1 day (24 hours), 1 week, 1 month, 3 months, 6 months, and 9 months after bleaching. The Commission Internationale de l'Eclairage (CIE) L'a'b* color change (ΔE*) at each timepoint was calculated and compared using repeated-measures analysis of variance. All bleaching techniques effectively whitened the teeth to a clinically perceptible level (ΔE* > 3.3), and there were no statistically significant differences among the groups (P > 0.05). The mean ΔE* values of the laser groups were not significantly different from the mean value of the control group during the 9-month evaluation period (P > 0.05). However, statistically significant differences among the groups were noted when color measurements at the following timepoints were compared: immediately after bleaching vs 1 day; 1 day vs 1 week; and 3 months vs 6 months (P < 0.05). Use of a 940-nm diode laser, 980-nm diode laser, or conventional hydrogen peroxide gel provided equally effective bleaching. The color change remained clinically perceptible throughout the 9-month period. [ABSTRACT FROM AUTHOR]

Bone-marrow derived stem cells (BMSCs) can differentiate into several mesenchymal cell lines that are suitable for bone and dental tissue engineering. This study was aimed to assess the efficacy of cell therapy in direct pulp capping (DPC) of canine teeth using autologous BMSCs along with collagen/hydroxyapatite hybrid scaffold in terms of the quantity and quality of calcified bridge formation. The teeth were randomly divided into three groups of DPC with mineral trioxide aggregate (MTA), hydroxyapatite/collagen hybrid scaffold alone and BMSCs with hydroxyapatite/collagen hybrid scaffold. DPC was performed under general anesthesia in cavities prepared on the buccal surfaces of mandibular and maxillary premolars of the same dogs from which, stem cells had been isolated. All cavities were then restored with light-cure resin modified glass ionomer cement. Histomorphometric assessments after 12 weeks showed formation of dentinal bridge following DPC with BMSCs and MTA. The efficacy of MTA for calcified bridge formation following DPC was significantly higher than that of BMSCs plus hybrid scaffold. According to the present study, we concluded DPC using BMSCs and hybrid scaffold did not provide clinically noticeable results in canine patients. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to determine the bond strength of fiber post to composite core following surface treatment with Er,Cr:YSGG laser at different powers and sandblasting with and without thermocycling. Methods: In this experimental study, 30 fiber posts (Glassix, Nordin, Switzerland) were randomly divided into 5 groups of sandblasting, no treatment and laser irradiation at 1, 1.5 and 2 W powers. Following composite filling and mounting, 1-mm thick sections were made for pushout bond strength testing. Half of the samples in each group were subjected to thermocycling (n=15). Two-way analysis of variance (ANOVA) was used to analyze the bond strength values. Pairwise comparisons were made using Tukey test (P < 0.05). Results: Effect of treatment method on push-out bond strength of fiber post to composite core was significant (P = 0.017), while thermocycling had no significant effect on bond strength (P = 0.964). Pairwise comparison of surface treatment methods revealed no significant difference in groups with and without thermocycling (P > 0.05), but Er,Cr:YSGG laser irradiation with 1 W power yielded significantly higher bond strength than the control group (P =0.01). Conclusion: Irradiation of Er,Cr:YSGG laser at 1 W power increased the bond strength of fiber post to composite core. Thermocycling slightly decreased the bond strength at the fiber postcore interface. [ABSTRACT FROM AUTHOR]

The efficacy of methods like e-learning as a supplement to traditional face-to-face instruction needs to be evaluated in dental courses. This study aimed to assess the efficacy of posting case presentations on one of the educational websites of the virtual school of Tehran University of Medical Sciences called "SARMAD" to enhance the ability of senior dental students to diagnose tooth discolorations and offer treatment plans. This experimental study had a pre-test/post-test control group design and was conducted on 63 senior dental students. After filling out the primary questionnaire and obtaining a written informed consent, students participated in a pre-test and were then randomly divided into two groups of intervention and control. Fifteen case presentations were posted on the university website (SARMAD) during 6 weeks and discussed. Then, students participated in a post-test. Students' perspectives and their satisfaction with the website were assessed by a questionnaire. For ethical purposes, the same program was also offered to the controls. The post-test score was significantly higher than the pre-test score in the intervention group (P<0.001); but in the control group, the post-test score was only slightly higher than the pre-test score (P=0.128). In the intervention group, 70% stated that they would suggest this method as an efficient educational modality; 93.3% stated that this method would be beneficial as a supplement to conventional education; 16.7% ranked the SARMAD website excellent, 30% ranked it good, 33.3% acceptable, 16.7% moderate and 3.3 poor. It appears that this instructional modality may be efficiently used as a supplement to traditional instruction in undergraduate dental curricula. [ABSTRACT FROM AUTHOR]

Statement of the Problem Acidic foods and drinks can erode composite resins. Silorane-based composite is a new low shrinkage composite with higher hydrophobicity which might resist the erosive effect of beverages. Purpose The aim of this study was to determine the effects of 100% orange juice and non-alcoholic carbonated beer on microhardness of a silorane-based composite in comparison with two methacrylate-based composite resins. Materials and Method Ninety disc-shaped composite specimens were fabricated of Filtek P90, Filtek Z350 XT Enamel and Filtek Z250 (3M-ESPE) (n=30) and randomly divided into 3 subgroups of 10.Group 1 was immersed in distilled water, group 2 in 100% orange juice, and group 3 in non-alcoholic beer for 3 h/day. Primary, secondary and final Vickers microhardness tests were performed at the beginning of the study and 7 and 28 days later. Surface of 2 specimens in each group was evaluated under scanning electron microscope on day 28. Data were analyzed using repeated measures of ANOVA model (α=0.05). Results The primary and secondary microhardness of P90 was significantly lower than that of Z350, and Z250 (p< 0.001). Microhardness of Z350 was also lower than that of Z250 (p= 0.002). On day 28, microhardness of P90 was lower than Z250 and Z350 (p< 0.001); however, microhardness values of Z250 and Z350 were not significantly different (p= 0.054). Microhardness of specimens subjected to non-alcoholic beer was significantly lower than that of controls (p= 0.003). Meanwhile, the microhardness value of resins in orange juice was somewhere between the two mentioned values with no significant difference with any of them (p> 0.05). Conclusion Although 28 days of immersion in 100% orange juice and non-alcoholic beer decreased the microhardness of all specimens, P90 experienced the greatest reduction of microhardness and non-alcoholic beer had the highest effect on reducing microhardness. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the effect of 30% hydrogen peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites. Materials and Methods: A total of 96 standard class V cavities (1.5 × 2 × 3 mm) were prepared on the buccal surface of sound extracted human premolars with both enamel and dentin margins and randomly assigned into three groups of Filtek P90 (group A) with its respective bonding (P90 system adhesive), Filtek Z250 (group B) and Filtek Z350XT (group C), both with Adper Prompt L-Pop bonding. The teeth were subjected to thermocycling (1000×, 5-55°C) and half of them randomly underwent bleaching (30% hydrogen peroxide, 15 min, three times), while the remaining half (control) were not bleached. Dye penetration was measured following immersion in 2% basic fuchsin for 24 h. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at 95% CI. Results: No significant differences were found between the composites in the control groups in enamel (P=0.171) or dentin (P=0.094) margins. After bleaching, microleakage of Z250 (at the occlusal (P=0.696) or gingival (P=0.867) margins), Z350 (at the occlusal (P=0.323) margin) and P90 (at the occlusal (P=0.316) or gingival (P=0.281) margins) did not change significantly. Conclusion: No significant differences were noted between the bleached and control subgroups of Z250 and P90 in enamel or dentin margins. Microleakage of Z350 composite was reduced at the gingival margin compared to the control group, but no significant difference was observed at the occlusal margin. Microleakage of siloranebased composite in gingival margin was significantly more than two metacrylatebased composites. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to assess the color changes in artificially induced incipient caries after photodynamic therapy (PDT) using different concentrations of methylene blue and toluidine blue, along with irrigation using water and hypochlorite., Materials and Methods: Forty-two sound human premolar teeth were used to create two artificial incipient carious lesions. One lesion was placed on the buccal surface and the other on the lingual surface. The color of these artificial incipient carious surfaces was determined using the CIE L   ∗ a   ∗ b   ∗ color system. The teeth were then randomly assigned to 12 groups ( n  = 7) based on the PDT method. These methods included methylene blue with concentrations of 50, 100, and 150  µ g/mL, followed by water irrigation, methylene blue with concentrations of 50, 100, and 150  µ g/mL, followed by hypochlorite solution irrigation, toluidine blue with concentrations of 50, 100, and 150  µ g/mL, followed by water irrigation, and toluidine blue with concentrations of 50, 100, and 150  µ g/mL, followed by hypochlorite solution irrigation. The teeth underwent a colorimetry procedure again, and the resulting color changes were calculated. A three-way ANOVA was performed to analyze the effects of laser wavelength, concentration of the light-absorbing material, and irrigation solution on ΔE ., Results: The results showed that the color changes caused by toluidine blue photosensitizer at a concentration of 100  µ g/mL, with both water and hypochlorite irrigation, were not noticeable to the naked eye ( ΔE water = 3.04, ΔE hypochlorite = 2.00). However, in the other study groups, the color changes were perceptible ( ΔE  > 3.3). There were no significant differences in ΔE between different concentrations of methylene blue and toluidine blue when using either water or hypochlorite irrigation ( P   > 0.05). A significant difference was observed between methylene blue and toluidine blue at a concentration of 100  µ g/mL with water irrigation ( P =0.006). Additionally, a significant difference was found between methylene blue and toluidine blue at a concentration of 100  µ g/mL with hypochlorite irrigation ( P =0.049). However, no significant differences were observed between methylene blue and toluidine blue at other concentrations with either water or hypochlorite irrigation ( P   > 0.05)., Conclusion: In conclusion, tooth color in teeth with incipient caries did not change significantly after PDT using toluidine blue (the photosensitizer) at a concentration of 100  µ g/mL with either water or 1% hypochlorite solution irrigation for 5 s., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2024 Sedighe Sadat Hashemikamangar et al.)

Introduction: Fiber-reinforced composite posts (FRCP) have become popular due to their multiple advantages in teeth with extensive crown destruction. Proper disinfection is essential for the successful bonding of these posts. Commonly used solutions for cleaning and disinfecting the root canals adversely affect the bond strength (BS). Photodynamic therapy is an alternative method for irrigating the root canal and disinfecting the post space.This study was designed to evaluate the impact of photodynamic therapy on the BS of fiber posts to root canal dentin. Methods: Human maxillary canines were recruited for this study. The tooth crowns were removed at the cervical line and endodontically treated. After fiber post spaces were prepared, the teeth were assigned to five groups based on the light-sensitive material: deionized water, indocyanine green and 810-nm laser, methylene blue and 660-nm laser, toluidine blue and 635-nm laser, curcumin and LED. The posts were cemented after photodynamic therapy. Cervical, middle, and apical samples were prepared by transverse sectioning. Push-out bond strength (PBS) values were measured in a universal testing machine. Finally, the data underwent statistical analyses with ANOVA and Howell-Games tests. Results: One-way ANOVA revealed no significant differences between the groups ( P <0.001). The Games-Howell test showed that curcumin (7.23±3.75) and the control group (5.92±4.04) had a similar BS ( P >0.005). The BS was lower in the methylene blue (3.34±2.15), indocyanine green (2.59±3.16), and toluidine blue (2.45±1.73) groups than in the control group ( P <0.005). Conclusion: Unlike other light-sensitive materials, curcumin did not adversely affect the BS., Competing Interests: None., (Copyright © 2024 J Lasers Med Sci.)

Background: Small chipping or fracture of ceramic restorations may be repaired by composite resin instead of replacing the restoration. This method is faster and cheaper compared to restoration replacement. Several strategies have been suggested to obtain a high repair shear bond strength (SBS). This study aimed to assess the efficacy of some new ceramic surface treatments (laser and universal adhesive) to enhance the repair bond strength of composite resin to ceramic compared to the conventional method., Materials and Methods: This in vitro study evaluated 80 IPS Empress Esthetic ceramic plates in eight groups ( n = 10). The ceramic surface was polished with 320-grit silicon carbide paper under running water, rinsed with water spray for 10 s and dried. The samples were then divided into two subgroups for mechanical surface preparation with hydrofluoric (HF) acid and Er: YAG laser (2 W, 200 m J, 10 Hz, 10 s). Each group was divided into two subgroups for use/no use of silane. The conventional or universal adhesive was then applied on the samples in each subgroup. Composite cylinders were bonded to the ceramic surface using plastic tubes. The samples were stored in distilled water at 37°C for 24 h and subjected to an SBS test. Data were analyzed using one-way ANOVA ( P < 0.05)., Results: The interaction effect of variables on SBS was significant. Maximum SBS was noted in HF acid + silane + conventional adhesive group (mean: 12.0481 MPa). Minimum SBS was noted in the laser + conventional adhesive group (mean: 2.5766 MPa). Surface treatment with HF acid yielded significantly higher SBS than laser ( P < 0.001). The interaction effect of conventional/universal adhesive and use/no use of silane on SBS was statistically significant., Conclusion: The repair SBS was higher in groups treated with HF acid compared to laser. Ceramic surface treatment with HF plus silane plus conventional adhesive yielded a higher SBS as well as HF plus Universal adhesive. Thus, the application of silane as a separate step can be omitted in the repair of ceramic restorations with universal adhesives., Competing Interests: The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or nonfinancial in this article., (Copyright: © 2022 Dental Research Journal.)

Background: By an increase in use of composite restorations, some defects are also seen in these restorations, which need to be repaired. Since complete replacement of an old restoration may compromise the tooth structure, repair of defect is a more practical approach if there is no caries recurrence. Risk of pulp injury also decreases as such. One major challenge in restoration repair is to obtain a durable bond between the new and old composite. Laser irradiation has been suggested for surface preparation of old composite. This study aimed to assess the effect of composite surface preparation with Er,Cr:YSGG laser on microtensile bond strength to new composite., Material and Methods: A total of 18 blocks were fabricated in three groups of nanohybrid, microhybrid and Beautiful II giomer measuring 4x7x7 mm and subjected to 10,000 thermal cycles between 5-55°C with 30 seconds of dwell time. The samples were randomly assigned to no surface treatment (etching and bonding) or laser plus etching and bonding groups. Composite cylinders measuring 4x7x7 mm were fabricated of Beautiful, nanohybrid and microhybrid composites on old composite surfaces and subjected to 500 thermal cycles for 50 seconds between 5-55°C with 30 seconds of dwell time. Each block was sectioned into 10 samples and they were subjected to microtensile bond strength test. Data were analyzed using ANOVA and Tukey's test., Results: In all composites, the mean bond strength in laser subgroups was higher than that in control subgroups except for giomer, which showed lower bond strength in laser subgroup. The lowest mean bond strength was noted in repair of Z350XT with Z350XT when the surface of old composite was etched (10.92 MPa). The highest mean bond strength was noted in repair of Z250 with giomer when the old composite surface was irradiated with laser (30.55 MPa)., Conclusions: Er,Cr:YSGG laser plus etching increased the bond strength in all groups except for giomer group, which showed a reduction in bond strength. Key words: Composite resins, surface treatment, tensile bond strength, laser, er,cr:ysgg, giomer., Competing Interests: Conflict of interest statement: The authors have declared that no conflict of interest exist.

Background: Repair of composite restorations is a conservative method that can increase the longevity and durability of restorations while preserving the tooth structure. Achieving a suitable bond between the old and new composite is difficult. To overcome this problem, some methods have been recommended to increase the repair bond strength of composite.This study aimed to assess the effect of aging by thermocycling (5,000 and 10,000 cycles) and mechanical surface treatments (Er,Cr:YSGG laser and bur) on repair shear bond strength of composite resin., Material and Methods: Totally, 120 composite blocks measuring 6x4x4 mm were fabricated of Filtek Z250 composite and were randomly divided into three groups (n=40) based on initial aging protocol: (a) no aging: storage in distilled water at 37°C for 24 hours, (b) 5,000 thermal cycles, (c) 10,000 thermal cycles. Each group was then randomly divided into two subgroups (n=20) based on mechanical surface treatment (laser and bur). The laser and bur-prepared surfaces were silanized and Adper Single Bond 2 was then applied. The repair composite was bonded to surfaces. Half of the samples in each subgroup (n=10) were subjected to 5,000 thermal cycles to assess durability of bond. The remaining half were stored in distilled water at 37°C for 24 hours and all samples were then subjected to shear bond strength testing in a universal testing machine with a crosshead speed of 1mm/min. Data (in megapascals) were subjected to one-way ANOVA and Tukey's test (P=0.05). Mode of failure was determined under a stereomicroscope., Results: Bur preparation significantly improved the bond strength compared to laser ( P <0.001). Aging by 10,000 thermal cycles significantly decreased the repair bond strength of composite ( P <0.001). No significant difference was noted in this regard between distilled water and 5,000 thermal cycles groups ( P =0.699). Primary bond strength and bond strength after 5,000 thermal cycles in the same subgroups were not significantly different either ( P =0.342)., Conclusions: Aging by 10,000 thermal cycles significantly decreases the repair bond strength of composite and surface preparation by bur provides a higher bond strength compared to laser. Key words: Thermocycling, Composite, Repair, Laser., Competing Interests: Conflict of interest statement:The authors declare that they have no conflict of interest.

Objectives: The aim of this study was to assess the effect of 30% hydrogen peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites., Materials and Methods: A total of 96 standard class V cavities (1.5 × 2 × 3 mm) were prepared on the buccal surface of sound extracted human premolars with both enamel and dentin margins and randomly assigned into three groups of Filtek P90 (group A) with its respective bonding (P90 system adhesive), Filtek Z250 (group B) and Filtek Z350XT (group C), both with Adper Prompt L-Pop bonding. The teeth were subjected to thermocycling (1000×, 5-55ºC) and half of them randomly underwent bleaching (30% hydrogen peroxide, 15 min, three times), while the remaining half (control) were not bleached. Dye penetration was measured following immersion in 2% basic fuchsin for 24 h. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at 95% CI., Results: No significant differences were found between the composites in the control groups in enamel (P=0.171) or dentin (P=0.094) margins. After bleaching, microleakage of Z250 (at the occlusal (P=0.696) or gingival (P=0.867) margins), Z350 (at the occlusal (P=0.323) margin) and P90 (at the occlusal (P=0.316) or gingival (P=0.281) margins) did not change significantly., Conclusion: No significant differences were noted between the bleached and control subgroups of Z250 and P90 in enamel or dentin margins. Microleakage of Z350 composite was reduced at the gingival margin compared to the control group, but no significant difference was observed at the occlusal margin. Microleakage of silorane-based composite in gingival margin was significantly more than two metacrylate-based composites.