Objectives: This study aimed to assess the self-reported knowledge and attitude of dentists towards fluoride prescription.

Materials and Methods: A questionnaire survey was conducted at the national annual dental congress in 2010 in Tehran-Iran. Dentists’ level of knowledge about the preventive effects of systemic and topical administration of fluoride was assessed as well as their attitudes towards its application. Self-reported practice for two paper patients (a child and an adult with high risk of dental caries) was assessed. Data were analyzed using SPSS, chi-square test and logistic regression.

Results: A total of 347 dentists including 232 (73.4%) males and 84 (26.6%) females responded; 84.7% agreed/strongly agreed with addition of fluoride to water and 66% agreed with prescription of fluoride tablets/drops in fluoride-deficient areas. Fluoridated toothpastes were considered useful by 85.3%; this rate was 78.7% for fluoride rinse and 87.6% for fluoride varnish, foam or gel. The majority of dentists (67.4%) reported no access to clear guidelines on fluoride application; 83% considered fluoride to be effective for caries prevention in children less than 12 years and 39.2% believed it was useful for adults and adolescents; 50% of the respondents correctly managed the high-risk child and adult with respect to appropriate selection of fluoride product. Younger dentists (OR=0.94; 95% CI 0.8-0.9; P=0.043) and new graduates (OR=0.94; 95% CI 0.89-0.99; P=0.034) were more likely to correctly manage the high-risk child.  

Conclusion: Dentists had good knowledge and positive attitudes towards fluoride application. New graduates were more likely to correctly manage the young high-risk patient.

Objectives: Several studies have assessed the characteristics and properties of silorane-based composites and adhesive systems. Considering the extensive application of tooth-whitening agents, possible deteriorative effects of tooth bleaching agents on these restorative materials must be studied. The aim of this study was to evaluate the effect of an in-office carbamide peroxide-based tooth bleaching agent on the wear resistance of a silorane-based and a conventional microhybrid dimethyl methacrylate-based dental composite with two different application times.  

Materials and Methods: Thirty cylindrical specimens were made of Z250 and P90 dental composite resins (n=15 for each composite). Samples made of each composite were divided into three groups (n=5) for immersion in an in-office bleaching agent (Opalescence® Quick 45%) for either three or eight hours or saline solution (control). Wear tests were conducted after bleaching using a pin-on disk apparatus under the load of 40N at a constant sliding speed of 0.5 ms^-1 for a sliding distance of 300 m. The samples were weighed before and after the wear test. Repeated measures ANOVA was used to statistically analyze the obtained data (α=0.05).

Results: There was a significant decrease in the weight of samples after the wear test (P<0.001). However, no significant difference was found among groups in the mean weight of samples before and after the wear test (P>0.05). 

Conclusion: Bleaching for three or eight hours using 45% carbamide peroxide had no deteriorative effect on the wear resistance of Z250 and P90 composites.

Objectives: This study aimed to compare the durability of four adhesive systems by assessing their microtensile bond strength (MTBS) and microleakage during six months of water storage.

Materials and Methods: A total of 128 human third molars were used. The adhesives tested were Scotch Bond Multipurpose (SBMP), Single Bond (SB), Clearfil-SE bond (CSEB), and All-Bond SE (ABSE). After sample preparation for MTBS testing, the microspecimens were subjected to microtensile tester after one day and six months of water storage. For microleakage evaluation, facial and lingual class V cavities were prepared and restored with composite. After thermocycling, microleakage was evaluated. Bond strength values were subjected to one-way ANOVA and Tamhane’s test, and the microleakage data were analyzed by the Kruskal-Wallis, Dunn, Mann Whitney and Wilcoxon tests (P<0.05).

Results: Single Bond yielded the highest and ABSE yielded the lowest bond strength at one day and six months. Short-term bond strength of SBMP and CSEB was similar. After six months, a significant decrease in bond strength was observed in ABSE and SBMP groups. At one day, ABSE showed the highest microleakage at the occlusal margin; however, at the gingival margin, there was no significant difference among groups. Long-term microleakage of all groups at the occlusal margins was similar, whilst gingival margins of SBMP and SB showed significantly higher microleakage.

Conclusion: The highest MTBS and favorable sealability were obtained by Clearfil SE bond. Water storage had no effect on microleakage of self-etch adhesives at the gingival margin or MTBS of CSEB and SB. 

Objectives: This study aimed to compare the diagnostic accuracy of inverted and unprocessed digitized periapical radiographs for detection of peri-implant defects.

Materials and Methods: A total of 30 osteotomy sites were prepared in three groups of control, study group 1 with 0.425 mm defects and study group 2 with 0.725 mm defects using the SIC and Astra Tech drill systems with 4.25mm and 4.85mm diameters. Small and large defects were randomly created in the coronal 8mm of 20 implant sites; implants (3.4mm diameter, 14.5mm length) were then placed. Thirty periapical (PA) radiographs were obtained using Digora imaging system (Soredex Corporation, Helsinki, Finland), size 2 photostimulable storage phosphor (PSP) plate sensors (40.0mm×30.0mm) and Scanora software. Unprocessed images were inverted using Scanora software by applying image inversion and a total of 60 images were obtained and randomly evaluated by four oral and maxillofacial radiologists. Data were analyzed using the t-test.

Results: Significant differences were observed in absolute and complete sensitivity and specificity of the two imaging modalities for detection of small and large defects (P<0.05). Unprocessed digital images had a higher mean in terms of absolute sensitivity for detection of small defects, complete sensitivity for detection of large peri-implant defects and definite rule out of defects compared with inverted images.

Conclusion: Unprocessed digital images have a higher diagnostic value for detection of small and large peri-implant defects and also for definite rule out of defects compared with inverted images.

Objectives: Color change of composite restorations is well known to dentists. However, the effect of commonly consumed drinks on discoloration of composite resins has yet to be
determined. This study sought to assess the color change of a nanofilled (Premise) and a flowable composite resin (Premise flowable) following simulated consumption of tea, cola, iron drops and multivitamin syrup.

Materials and Methods: Forty disk-shaped specimens (7 mm in diameter and 2 mm thick) were fabricated from each composite resin. The baseline color values were measured according to the CIE L*a*b* system using digital imaging. The specimens of each restorative material were randomly divided into five groups (eight each) according to the storage media namely tea, cola, iron drops, multivitamin syrup or distilled water (control). The specimens were immersed in staining solutions for three hours daily over a 40-day test period. Following this, the color change values (ΔE*) were calculated. For statistical analyses, the color differences were analyzed using two-way ANOVA and Tukey’s test (P< 0.05).

Results: There was no significant difference in ΔE* values between the two types of
composite resins (P>0.05). In both composite materials, the difference among the solutions was not significant (P>0.05). 

Conclusion: Under the tested experimental conditions, both restorative materials were
susceptible to discoloration by all four staining solutions. The color change values were not related to the solution or the type of material used.

Objectives: Fluoride therapy is important for control and prevention of dental caries. Laser irradiation can increase fluoride uptake especially when combined with topical fluoride application. The objective of this study was to compare the effects of CO₂ and diode lasers on enamel fluoride uptake in primary teeth.

Materials and Methods: Forty human primary molars were randomly assigned to four groups (n=10). The roots were removed and the crowns were sectioned mesiodistally into buccal and lingual halves as the experimental and control groups. All samples were treated with 5% sodium fluoride (NaF) varnish. The experimental samples in the four groups were irradiated with 5 or 7W diode or 1 or 2W CO₂ laser for 15 seconds and were compared with the controls in terms of fluoride uptake, which was determined using an ion selective electrode after acid dissolution of the specimens. Data were analyzed by SPSS version 16 using ANOVA treating the control measurements as covariates.

Results: The estimated amount of fluoride uptake was 59.5± 16.31 ppm, 66.5± 14.9 ppm, 78.6± 12.43 ppm and 90.4± 11.51 ppm for 5W and 7 W diode and 1W and 2 W CO₂ lasers, respectively, which were significantly greater than the values in the conventional topical fluoridation group (P<0.005). There were no significant differences between 7W diode laser and 1W CO₂ laser, 5W and 7W diode laser, or 1W and 2W CO₂ laser in this regard.

Conclusion: The results showed that enamel surface irradiation by CO₂ and diode lasers increases the fluoride uptake.

Objectives: Biomechanical preparation and irrigation with antimicrobial solutions are necessary to disinfect the root canal space. This in vitro study aimed to examine the antifungal effect of green tea extract on Candida albicans biofilm formed on tooth substrate.

Materials and Methods: Minimum fungicidal concentration (MFC) and minimum inhibitory concentration at which 90% of the isolates were inhibited (MIC90) were studied using green tea extract and sodium hypochlorite with the broth macro-dilution method. Then, anti-candida effects of this extract were tested on tooth substrates of 45 extracted single-canal premolar teeth. After biomechanical cleaning of the root canals, the teeth were sectioned vertically and randomly divided into three groups of 30. All the samples were infected with C. albicans (PTCC 5027) and exposed to the test solutions (sodium hypochlorite, green tea, normal saline) for five, 10 and 15 minutes. Data analyses of the samples were performed using two-way ANOVA.

Results: The average number of microorganisms showed a significant decrease after five, 10 and 15 minutes of exposure to green tea extract and sodium hypochlorite. The average number of C. albicans in green tea extract and sodium hypochlorite groups decreased to 1/3 and 1/2 of the initial values, respectively.

Conclusion: Antifungal activity of green tea extract was time-dependent and its inhibitory action did not decrease significantly over time. It is recommended to consider other properties of green tea such as tissue solubility, impact on dentin structure and use as an intracanal medicament or for smear layer removal in the clinical setting.

Objectives: This study aimed to assess and compare the apical sealing ability of HEROfill® Soft-Core system and lateral condensation technique in fine curved canals using the fluid filtration method.

Materials and Methods: Forty human mesiobuccal root canals of mandibular first molars with 25° to 40° curvatures were instrumented to an apical size 30/0.04. Roots were randomly assigned to two experimental groups of 15, designated as groups A and B. Two control groups, each containing five teeth, served as positive and negative controls. Group A was obturated using lateral condensation technique and group B with the HEROfill® Soft-Core system. The groups were tested for microleakage using an in vitro fluid filtration apparatus with 0.5 atm pressure at zero, two, four, six, eight and 10 minutes. Independent t-test was used to analyze the microleakage data.

Results: The mean and standard deviation (SD) values for fluid microleakage in the lateral condensation group were 0.58±0.49 µL/min, 0.68±0.35 µL/min, 0.74±0.22 µL/min, 0.71±0.29 µL/min and 0.60± 0.29 µL/min at two, four, six, eight and 10 minutes, respectively. The mean and SD values for fluid microleakage in the HEROfill® group were 0.53±0.42 µL/min, 0.67±0.34 µL/min, 0.69±0.26 µL/min, 0.73±0.33 µL/min and 0.63±0.26 µL/min at two, four, six, eight and 10 minutes, respectively. The difference between the lateral condensation and HEROfill® groups was not statistically significant at two (P=0.776), four (P=0.909), six (P=0.562), eight (P=0.861) or 10 (P=0.765) minutes.

Conclusion: The HEROfill® system and cold lateral condensation technique were equally effective for apical sealing of curved canals.

Objectives: Bleached enamel is more susceptible to staining, and application of remineralizing agents may decrease enamel susceptibility to staining. This study sought to assess the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on enamel susceptibility to staining during bleaching treatment.

Materials and Methods: Forty central and lateral incisors and first premolar teeth were evaluated in four groups of 10. Group one specimens were subjected to in-office bleaching. Group two underwent in-office bleaching followed by surface treatment with CPP-ACP. Group three specimens received home bleaching and group four underwent home bleaching followed by CPP-ACP surface treatment. After each course of daily bleaching, specimens were immersed in tea solution. Home bleaching (15% carbamide peroxide) was performed for 14 days and in-office bleaching (40% hydrogen peroxide) was carried out in two sessions with an eight-day interval. The color of specimens was analyzed at baseline and post-intervention using EasyShade Shade-Selection Device. Two-way ANOVA was used to evaluate the effects of bleaching type and surface treatment on color change. Then, the means were compared by Tukey’s HSD test (P=0.05).

Results: The interaction effect of surface treatment and type of bleaching was not significant on any color parameter (P>0.05). Surface treatment had significant effects on ΔL (P=0.004). Type of bleaching had a significant effect on "b" parameter (P=0.00). The effect of bleaching type on ΔE was significant (P=0.00) but the effect of surface treatment was not (P=0.34).

Conclusion: CPP-ACP had no significant effect on preventing enamel staining by tea during bleaching treatment.

Dental implants have provided exceptional rehabilitative options for edentulous and partially edentulous patients. However, as more implants come into play, the more the clinicians come across problems where specific considerations must be taken into account to meet expectations. The Toronto Bridge is a treatment modality proposed for restoring several teeth lost in patients with increased crown height (interarch) space. Herein, we applied the Toronto Bridge to rehabilitate a patient with generalized aggressive periodontitis; this article suggests that an implant-supported Toronto Bridge can be a reliable and acceptable treatment modality for patients suffering from tooth loss and vertical bone loss as the result of generalized aggressive periodontal disease.