Objective: Although oxidative mouthwashes have many antimicrobial benefits, it has been suggested that residual oxygen interferes with composite resin adhesion to dental structures. This study aimed ...to evaluate the effect of an oxidative mouthwash on the microleakage of composite restorations.Methods: Twenty-four extracted human third molars were randomly assigned into three groups: Group 1: a 0.05% sodium fluoride mouthwash, Group 2: an oxidative mouthwash, and Group 3: distilled water. The teeth were immersed in the corresponding solution for 10 minutes a day over 14 days. Class V cavities were prepared in the buccal and lingual surfaces of the teeth (n=15 per group) and restored with Filtek Z250 composite. The teeth were thermocycled between 5º C and 55º C for 1000 cycles, then immersed in 2% fuchsin solution for 24 hours, followed by sectioning in the bucco-lingual direction. The gingival and occlusal microleakage were inspected using a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. The statistical significance level was considered at P 0.05.Results: The highest and lowest average microleakage scores were observed at the gingival and occlusal margin of cavities immersed in the sodium fluoride mouthwash, respectively. No statistical differences were observed in microleakage among the three groups either at the occlusal or at the gingival margin (P>0.05). The Mann-Whitney U test showed a statistically greater microleakage at the cervical (1.05±1.1) compared to the occlusal (0.694±0.53) margins, irrespective of the treatment groups (P=0.033).Conclusions: Using an oxidative mouthwash does not affect the microleakage of composite restorations
Background: Applying silver diamine fluoride (SDF) is recommended to arrest and prevent dental caries. However, it may jeopardize the bond of the restorative materials to the tooth. The aim of the ...present in vitro study was to evaluate the effect of the simultaneous use of the SDF and potassium iodide (KI) on shear bond strength to the sound dentin.
Materials and Methods: In this in vitro study, on the buccal and lingual surfaces of the 48 human third molar teeth, dentinal surfaces with a diameter of 6 mm were created by removing the enamel. Then, the specimens were divided into four groups based on applying or not applying the KI/SDF and adhesive type (etch and rinse E and R or universal adhesive). Afterward, cylindrical composite restoration was made on the surfaces. Half of the specimens were subjected to 1000 cycles of thermocycling. Subsequently, the shear bond strength was evaluated by Universal testing machine. Furthermore, the type of failure was determined by a stereomicroscope. Data were analyzed by t-test and Chi-square at a significance level of P < 0.05.
Results: There were statistically significant differences in shear bond strength between Groups 1 and 3 (P < 0.05), whereas the bond strength difference between Groups 2 and 4 was not statistically significant (P = 0.609). Failures were predominantly of the mixed type in almost all groups.
Conclusion: Based on the results of this study, the superiority of shear bond strength of universal adhesive to the sound dentin compared to E and R adhesive was confirmed. Thus, using this type of adhesive is recommended under the condition that KI/SDF anticaries material is applied.
Objectives: The purpose of this research was to evaluate the effect of immediate placement of different restorative materials in comparison with a temporary restoration on the surface microhardness ...of mineral trioxide aggregate (MTA). Materials and Methods: Access cavities were prepared in 40 extracted human molars, and a 3-mm layer of MTA was placed in the pulp chamber. The samples were divided into eight groups (n=5). Ten minutes after the MTA placement, two groups were restored with Zonalin temporary restoration, while the other six groups were restored with glass-ionomer cement (GIC), resin-modified glass-ionomer (RMGI), or resin-based composite. In each group, the Vickers microhardness (VMH) of MTA was determined after 7 and 21 days. Data were entered into SPSS 17 software program and were analyzed by two-way analysis of variance (ANOVA). The significance level was set at 5%. Results: The type of restorative materials had a statistically significant effect on the microhardness of MTA (P=0.002). However, the microhardness of MTA was neither significantly influenced by the timing of final restoration (P=0.246) nor by the time-material interaction (P=0.116). Conclusions: Based on the results of the present study and by considering the limitations of laboratory studies, it is recommended to postpone the placement of final restorations until the underlying MTA is completely set. Otherwise, in the clinical conditions in which early covering of MTA is recommended, sufficient moist-curing and hydration should be guaranteed by selecting a restorative material with the lowest hydrophilic interaction energy.
Background: Pain and discomfort are common during orthodontic treatment.
Aim: The aim of this single blind clinical trial was to compare the effectiveness of oral calcium versus acetaminophen in pain ...reduction.
Materials and Methods: In this study, the patients recorded their pain on a 100-mm visual analogue scale (VAS). Forty female patients (14-19 years old) who had passed at least 2 months of their first orthodontic archwire placement and their pain intensity was 40-100 mm (VAS) were selected and randomly assigned to two groups. Psychotic status was measured using Hospital Anxiety and Depression Scale (HADS). In group 1 calcium forte tablets (500 mg) and in group 2 acetaminophen (325 mg) tablets were prescribed to be taken one tablet per day. After consumption of all tablets (n=60), pain intensity was measured and compared with that before drug therapy.
Results: The results indicated that the difference in pain intensity before and after drug administration in the calcium group was statistically significant (P<0.001), but not significant in the acetaminophen group (P=0.468). The difference between the pain reduction in the two groups were also statistically significant (P<0.001). In the calcium group 9.5% and in the acetaminophen group 15.8% had anxiety that was not statistically significant (P=0.631). In both groups, no subject had depression.
Conclusion: Calcium is more effective than acetaminophen in long-term pain reduction during orthodontic treatment.
Background and Aims: Insufficient adhesion between fiber post and root canal is the main reason for the failure of the restoration and the fiber post surface treatment can imprive the bond strength. ...Additionally, there is disagreement about the ideal method of preparation to achieve the desired bond. The aim of this study was to compare the effect of two surface treatment methods on push-out bond strength of fiber posts to root canals. Materials and Methods: In this study, 45 healthy incisor teeth underwent root canal treatment. After preparing the post space, they were divided into 3 groups of 15, based on the surface treatment methods of the fiber post. In the first group as control group, no surface treatment was done on the fiber post. In the second and third groups, sandblasting with Cojet sand particles and 810 nm diode laser were used for surface treatment, respectively. Then, fiber posts were placed in all root channels by a self-adhesive resin cement. Then, the roots were cut in such a way that from each, 3 pieces with a thickness of 1.5 mm were obtained. Finally, the push-out bond strengths were measured using a universal testing machine. Data were analyzed by ANOVA using SPSS software. The level of significance was considered at P<0.05. Results: The average bond strengths in three groups were as follows: control group, 2.877 ±1.430, sandblast group 6.318±3.444, and laser 4.224 ±1.890 MPa ± SD. The difference in the bond strength between the sandblast group and the control group was significant (P=0.001). However, the average of the bond strength of laser group was not significantly different from the control group. (P=0.03). Conclusion: The findings of this study showed that unlike diode laser radiation, the use of Cojet sand particles for sandblasting the fiber post surfaces significanlty improved the bond strength.
Background and Aims: Different factors play a role in causing tooth decay. Modern dentistry is looking for a way to prevent tooth decay and suggests different ways to increase remineralization. The ...aim of this study was to evaluate the effect of nanohydroxyapatite toothpaste and mouthwash on remineralization of primary enamel lesions and obstruction of tubules. Materials and Methods: In this study, 90 human extracted central teeth were used. Artificial decay was induced by placing the specimens for 72 hrs in a demineralization solution in an incubator at 37 °C. Hardness of the specimens was determined by a microhardness test before any surface treatment. The specimens were then divided randomly into 6 groups of 15. For 1-6 groups, the specimens were subjected to a pH cycling for 14 days, which included 3 hrs of demineralization and 21 hrs of remineralization. At the same time, 1-3 groups were in contact with diluted toothpaste in a ratio of 1:3 with deionized water at a rate of 5 ml twice a day for two min. Eac specimen of 4-6 groups was exposed to 5 ml of three types of mouthwashes for one min. Then, the specimens were cut in the buccolingual direction in order to simultaneously evaluate the dentinal tubules and Vickers microhardness test was performed again and the before and after microhardness values were compared. Then, the percentage of deposition on the surface and tubule obstruction were analyzed using SEM (Scanning electron microscope) (P=0.006). Data were analyzed using SPSS24 software bu the descriptive statistics, ANOVA analysis of variance, and multiple Tukey comparisons. Results: The results of analysis of variance test showed that there was a statistically significant difference in the microhardness changes between study groups (P=0.006). Also, in-group analysis of microhardness changes, there was a significant difference (P<0.0001). Besides, only in the group containing 0.5% nanohydroxyapatite toothpaste, more than 50% tubule deposition and obstraction was observed (P<0.05). Conclusion: According to the present study, nanohydroxyapatite can be one of the treatment strategies to repair incipient lesions of teeth and the addition of nanohydroxyapatite, preferably to toothpaste, increases the dental microhardness.
Background and Aims: Recently, the addition of nanoparticles into the restorative materials and tooth preparation by laser for improving the bond strength have been concidered by researchers. The aim ...of this study was to investigate the shear bond strength of the bioactive glass ionomer containing titanium particles and a conventional glass ionomer with two surface treatments by Er-YAG laser and conventional methods. Materials and Methods: In this in-vitro study, 64 sound extracted premolars were collected. For conventional method, the specimens were prepared in such a way that dentin surfaces with a depth of 0.5 millimeter created at distance of 2 mm from the joint of CEJ at the root or crown. In the laser group, after preparing the teeth, the surface area was prepared by Er-YAG laser. Then, in the middle part of the buccal surface, a cylindrical mold with dimensions of 3.5 mm in diameter and 4 mm in height was placed and for each group was filled with its own glass ionomers. The specimens were divided into 8 groups by simple random sampling (n=8): A (laser, conventional glass ionomer, coronal dentin)/ B (laser, glass ionomer containing titanium nanoparticle, coronal dentin)/C (conventional, conventional glass ionomer, coronal dentin)/ D (conventional, glass ionomer containing titanium nanoparticle, coronal dentin)/ E (laser, conventional glass ionomer, root dentin)/ F (laser, glass ionomer containing titanium nanoparticle, root dentin)/ G (conventional, conventional glass ionomer, root dentin)/ H (conventional, glass ionomer containing titanium nanoparticle, coronal dentin). Finally, the shear bong strength by a universal testing machine was measured at a cross-head speed of 1 mm/min. For data analysis, Two-way ANOVA test was used to evaluate the effect of each variable and their interaction on the shear bond strength and Tukey test was used to compare the two groups. Results: There was significant difference only between groups B with C (P=0.002), E (P=0.007), G (P=0.001) and H (P=0.01). The highest bond strength was found for group B (laser, glass ionomer containing titanium nanoparticle, coronal dentin) and the lowest bond strength for group G (conventional, conventional glass ionomer, root dentin). Conclusion: All three factors of Er-YAG laser, glass ionomer containing titanium nanoparticle and coronal dentin had a positive effect on the improvement of the bond strength.
Background and Aims: Restoration of non-carious cervical lesions (NCCLs) is challenging due to the difficulty of adhesion of dental tissues. The aim of this study was to investigate the effects of ...three methods of surface treatments using diamond bur, Er: YAG laser and sandblasting on the microtensile bond strength of resin composite to the noncarious dentin in cervical lesions. Materials and Methods: In this in vitro study, 48 canine and premolar extracted human teeth with NCCLs at the buccal surface were selected and randomly divided into 4 groups of twelve each: control group without any treatment, Er: YAG laser group, diamond bur group and sandblasting group. For all groups, the bonding agent used was Clearfil SE Bond and then the cavities were filled with the Filtek Z250 resin-composite. After this step, the teeth were cut and then subjected to the microtensile bond strength test. Data were analyzed by the Kruskal Wallis test. Results: According to the obtained results, the microtensile bond strength, from the highest to the lowest values were in the sandblast group (24.57±10.24 MPa), the diamond bur group (19.19±10.8 MPa), laser group (18.59±9.05 MPa) and the control group (18.56±9.27 MPa), respectively. Although, no statistically significant difference was found between any of the groups (P=0.266). Conclusion: It seems that in teeth with NCCLs, the sandblasting method had a much better effect on the bond strength, although no statistically difference between surface treatment methods was found.
Objective: Degree of Conversion (DC) of Resin-Based composites (RBCs) is a concern and is affected by different factors. This study was conducted to evaluate the effect of different thicknesses and ...storage times on DC of bulk-fill and universal RBCs using the FTIR method. Material and methods: For each of dental composite (Tetric N- Ceram Bulk Fill and Tetric N Ceram), 28 samples were prepared (14 samples with 2 mm height and 14 samples with 4 mm height). One and seven days (1d and 7d) after storage in an incubator at 37 ?C, DC was measured and recorded using a FTIR device. Data were analyzed using t-test and Three-Way ANOVA and Tukey Post-Hoc Test. P < 0.05 was considered statistically significant. Results: DC of Bulk-fill composite is greater than universal composite. DC at 2 mm thickness is more than 4 mm. Unlike universal composite, 7d DC of Bulk-fill composite is greater than 1d. Of course, none of these differences are statistically significant (P-value > 0.05). Conclusions: Considering the limitation of this study, since no difference was found between DC of 1d and 7d, 1d DC is sufficient for clinical procedures, such as polishing, and the laboratory tests.KEYWORDSBulk-fill composites; Degree of Conversion; FTIR.
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