Journal of Dental Medicine

Background and Aims: Radiography is one of the most important para-clinical methods in diagnosing and selecting treatment in dentistry. Due to the potential dangers of X-rays for patients, the professional responsibility of the dentist requires that unnecessary radiographs to be avoided. The aim of this study was to investigate the awareness of dentists in Zanjan about the principles of radiation protection in 2019.
Materials and Methods: This cross-sectional study was performed on 107 general dentists and specialists working in Zanjan and the questionnaires were distributed among them. The level of awareness of dentists in 27 questions of radiographic prescribing questionnaire was evaluated and in each of the mentioned questions, their gender, age, work experience, participation in retraining, having X-ray machine in the field of dentistry and type of activity were evaluated. Data were analyzed by Chi-square test, Independent T-test, and ANOVA using SPSS software version 22.
Results: The results showed that the level of knowledge of general dentists about the principles of radiation protection (14.35±3.08) was lower than that of specialized dentists (17.19±2.35). Those who participated in retraining workshops (13.85±2.99) had less knowledge than those who did not (15.97±3.97), which was statistically significant (P<0.05); However, there was no significant difference in the dentists' knowledge about the principles of radiation protection based on gender, age, type of activity, having an X-ray machine at the place of treatment, and history of clinical experience (P≥0.05).
Conclusion: Awareness of dentists at various levels was moderate. Therefore, designing and holding more purposeful retraining courses to maintain and improve the level of awareness of dentists according to the guidelines provided by the authorities, still seems to be necessary.

Background and Aims: Regarding the need for social accountability in dental education, community-based dental courses has been established to improve the oral health of the community and compensate the shortcomings of the health system. Due to the importance of evaluation, the aim of this study was to determine the dental students’ attitudes and believes in the last year of their study towards the community-based dental education.
Materials and Methods: This cross-sectional study was performed on 159 dental students in the sixth year (October and February, 2018) of Isfahan dental school by census. These students took the relevant questionnaire, which was developed by researchers in three sections of “attitudes toward field activities”, “lessons and experiences of field activities during dentistry training” and “barriers and problems of field activities”. Its content and face validity was confirmed. They completed it on their own and after collecting information and descriptive analyzes, the relationship between the gender and entry group with attitude scores was analyzed by Mann-Whitney U test.
Results: Out of a total of 102 questionnaires which were answered (response rate of 64%), half of the students believed in the need to provide dental services in the form of mobile/outreach services for the community. 90% of the students agreed with the combination of field education with routine education in the dental schools. They also considered these services as an opportunity to use their experiences and knowledge to promote oral health in the community. 84% of them believed that their self confidence improved while providing services outside the faculty. In many of the propositions in the field of attitude to provide service in the field, a significant percentage (50 to 60%) did not have an opinion.
Conclusion: There was a good and positive aspects in many areas of attitude toward providing services in social fields as well as attitude towards the lessons learned from community-based dental education. However, we should consider the attitude-emotional aspects of educational objectives in the community-based courses in dental schools.

Background and Aims: A significant percentage of children with dental caries require, hospital dentistry and their parents do not have much information in this regard. The aim of this study was to determine the knowledge, attitude and practice of pediatricians in hospital dentistry in Isfahan Province.
Materials and Methods: This cross-sectional study was performed on 100 pediatricians working in Isfahan. The self-administered questionnaire included demographics of doctors and 19 questions for assessing the knowledge, attitude and practice of pediatric practitioners about hospital dentistry under general anesthesia. Raw data were analyzed by Chi-square test using SPSS software version 23.
Results: 100 pediatricians with an average age of 44.1±5.7 years (57% male) completed the questionnaire. 53% of the pediatricians had a high level of awareness about hospital dentistry and 42% about its related guides. 66% practitioners had a favorable attitude toward general anesthesia and costs, while 71% considered the parents' awareness were poor about hospital dentistry. Only 43% of pediatricians performed oral examinations in their daily visits, and 17% had a referral for hospital dentistry. Male pediatricians aged from 35 to 45 had a higher level of knowledge about hospital dentistry. The attitude and practice of pediatricians did not have a significant relationship with their age. Meanwhile, male pediatricians had better performance in oral and dental examination and referral for hospital dentistry (P=0.15).
Conclusion: From the results of this study, there is a need for a serious improvement in the level of knowledge, attitude, and practice of pediatricians in the field of hospital dentistry.

Background and Aims: Removable partial denture (RPD) is a common treatment to restore partially edentulous areas; however, a limited number of studies have been made on oral hygiene habits among patients with RPD. The aim of this study was to evaluate the patients’ knowledge about various cleaning methods of RPD to consciously improve hygienic habits of the patients.
Materials and Methods: This study was a cross-sectional study performed on 96 RPD patients referred to Jundishapur faculty of dentistry from 1395 to 1396. Demographic data namely age, sex, level of education, and other information about general health status, duration of dentures usage, and denture cleaning frequency were taken by the census through questionnaires. The descriptive statistics, chi-square, and T-test were used for statistical analysisof data (P<0.05).
Results: The patient age, sex, and smoking habits had significant effects on the prosthesis maintenance habits (P<0.05). The patients over 50 years of age, females, and nonsmokers significantly preferred dipping method over other RPD storage methods (P<0.05). The frequency of denture cleaning was significantly greater in males (53.3%) compared to females (23.9%) (P<0.05).
Conclusion: According to the results of this study, most RPD patients did not clean their dentures appropriately and have little knowledge on how to maintain and clean them. Regular and periodic recall and written instructions might be helpful to improve patients' awareness on proper cleaning and maintenance of partial dentures.

Background and Aims: Poly methyl methacrylate (PMMA) is still the most commonly used material in prosthetic dentistry. However, there are problems with the mechanical properties of this type of material including low flexural strength. Addition of nanoparticles into the polymer is one way to improve the mechanical properties of acrylic resin. In the present study, the effect of silicon dioxide (SiO₂) nanoparticles addition into the heat-cured acrylic resin in different concentrations was investigated. Because of the controversy had been observed in previous articles, the aim of this study was to investigate the mechanical properties of PMMA/SiO₂ nanoparticle obtained from different percentages of SiO₂.
Materials and Methods: In this in-vitro study, acrylic resin specimens containing 0, 1, 3 and 5% silicon dioxide (SiO₂) were prepared. The specimens were placed inside the gypsum molds and placed under pressure for three times. The mold cured in boiling water for 30 min. A trimmer was used to remove the additives. Sandpapers with 180, 320 and 600 grains of silicon-carbide were used for final finishing and polishing. Finally, the flexural strengths were measured using a universal testing machine. Data were finally analyzed by ANOVA and Tukey tests at a significant level of 5% using SPSS software.
Results: The mean flexural strengths and standard deviations of control group, 1% filler, 3% filler, and 5% filler, were 57.24±8.30, 69.98±7.26, 60.16±9.18, and 61.59±9.28 MPa, respectively. After comparing significant values between each group with the control group, a significant difference was observed between the control and 1% filler group (P=0.021). However, no significant difference was observed between 3 and 5% fillers with the control group or each other. The significant differences (P-value) between 3% filler and control group were 0.892 and between 5% filler and control group was 0.975.
Conclusion: The results of the present study showed that the use of low percentage of silicone dioxide (SiO₂) nanofiller could improve the flexural strength of poly methyl methacrylate acrylic resin.

Background and Aims: Pulpal exposures originated from the external cervical root resorptions have major effects on the treatment and prognosis. Therefore, the aim of this study was performed to compare the two different imaging systems-digital radiography with PSP (Photostimulable Phosphor) sensor in three horizontal different views and CBCT (cone beam computed tomography) images to assess the pulpal exposure in simulated cavity of external cervical root resorptions that was performed in 1398 in the School of Dentistry of Azad University.
Materials and Methods: 40 intact maxilla anterior teeth with straight roots were included. Teeth were randomly divided to two groups (20 teeth with and 20 without pulpal exposures). Each sample was assessed using PSP digital radiography (in 3 horizontal angles) and CBCT image system, to detect the presence of pulpal exposures. False negative and false positive results in 2 imaging procedures were judged with ratio test.
Results: The results showed in CBCT (P.P.V=85.7%) and (N.P.V=89.5%), and in digital intraoral radiography (P.P.V=80%) and (N.P.V=80%) in proximal defects. Ratio test showed that there were no significant differences in the proximal defects (P<0.4).
Conclusion: The results showed that there were no significant differences in detection of exposure in the proximal surfaces between two imaging systems.

Background and Aims: Periodontitis is an inflammatory multifactorial disease in oral tissues and many genetic reasons and environmental factors responsible. Vitamin D deficiency has been determined to be related to periodontal disease. This aim of this study was to investigate the association between rs7975232 polymorphism in vitamin D Receptor gene and periodontitis in 100 patients (as patient and control groups).
Materials and Methods: Blood samples from 50 patients and 50 control groups were selected and DNA from the samples was extracted by the DNA extraction kit. Genotyping was used by Tetra Arms-PCR method. The use of sequencing was confirmed by the Tetra Arms-PCR genotyping results. Then, statistical analysis was performed using SPSS statistics 20 software and T-test.
Results: Frequency of AA, AC, and CC Genotypes were 25 (50%), 14 (28%), and 11 (22%) in patients’ cases, and 26 (52%), 16 (32%) and 8 (16%) in controls, respectively. AA genotype was the highest genotype between the patient and control groups. Statistical analysis showed no significant association between this type of polymorphism and periodontitis disease in the studied samples (P=0.67).
Conclusion: This finding showed there was not significant association between rs7975232 polymorphism in vitamin D Receptor gene and periodontitis disease in the studied samples. To confirm the results of this study, further studies with large sample size and different types of population are recommended.

Conclusion: The high prevalence of TMD and related factors, such as a history of jaw dislocation, posterior edentulousness, earache, and clenching, requires attention to be identified and treat these problems.

Background and Aims: Nowadays, new techniques are used to control dental caries that have the ability to kill cariogenic bacteria. Recently, the addition of antibiotics to glass ionomers has been proposed to reduce the overall number of saliva bacteria. The aim of this study was to compare the antimicrobial effect and compressive strength of resin- modified glass ionomer (RMGI) containing different antibiotics on Streptococcus mutans.
Materials and Methods: A total of 120 specimens were prepared in 3 groups (n=40) including RMGI containing doxycycline with a concentration of 1.5%, RMGI containing a combination of ciprofloxacin, metronidazole and minocycline with a concentration of 1.5%, and RMGI without antibiotics as control group. To measure the antibacterial effect, the disk diffusion method and counting of Streptococcus mutans bacterial colonies were used and then the compressive strength test was performed. Data were collected into SPSS25 and analyzed by ANOVA and Kruskal-Wallis tests and the significance level was considered α=0.05.
Results: The mean number of bacterial colonies in the RMGI group containing doxycycline in all three time intervals 1, 24 hours and 7 days was significantly lower than the specimens in the RMGI group containing the triple antibiotic (P<0.001). The mean compressive strength of the two experimental groups was lower than the control group but was not statistically significant (P=0.326).
Conclusion: The addition of antibiotics at a concentration of 1.5% to RMGI resulted in a favorable antibacterial property with no significantly change in the compressive strength.

Background and Aims: Dental aesthetics has become an important issue in contemporary society. This study was designed to evaluate the patients’ satisfaction with their dental appearance and tendency to improve dental aesthetics.
Materials and Methods: In this descriptive study, a questionnaire with 17 questions was used to collect data from 200 patients referred to the dental school of Isfahan University of Medical Sciences from April-July 2019. A valid and reliable self-administrative questionnaire consisted of questions about the appearance of anterior teeth, receiving cosmetic treatments, and favorite aesthetic dental treatments was designed and used. Data were fed into SPSS22 and analyzed by Mann-Whitney, Kruskal Wallis and Spearman correlation tests (α=0.05).
Results: Among the participants, 27.5% (n=45) were dissatisfied with the appearance of their anterior teeth and the major reason for this dissatisfaction was related to the tooth color (35.8%, n=71). It was also observed that approximately 84% (n=168) of the patients had a history of smile concealment because of their teeth appearance. Among cosmetic dentistry treatments, aesthetic restorations were more commonly used than other treatments (20.5%, n=41). However, the most desired cosmetic treatments were teeth whitening (78.4%, n=156). There was no significant relationship between the satisfaction with the appearance of teeth and interest in the orthodontic treatment with age and education level (P=0.6).
Conclusion: Teeth color was the most important factor determining the degree of satisfaction with the appearance of teeth. Most of subjects desired to receive an aesthetic dental treatment and teeth whitening was the most popular aesthetic dental treatment.

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.

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: Finishing and polishing of composites is a critical step influencing the clinical service of restorations. The aim of this article was to evaluate and compare the effect of two liquid polishes on the polish retention of two nanocomposites.
Materials and Methods: Eighty standardized disk-shaped specimens (4×2 mm) were prepared from two nanocomposites (n=40), including one nano-filled composite (Filtek Z350 XT-3M ESPE, USA) and one nano-hybrid composite (Aelite Aesthetic Enamel-Bisco, Inc. Schaumburg, USA). The specimens were randomly divided into 4 subgroups (n=10) based on the method of finishing (F) and polishing (P) procedures: M: as control, polymerized under Mylar strip; S: finish and polish with a sequence of Sof-Lex discs (3M ESPE, USA); SP: finish and polish with Sof-Lex discs and use of Permaseal liquid polish (Ultradent products, Inc. USA); SB: finish and polish with Sof-Lex discs and use of Biscover liquid polish (Bisco, Inc. Schaumburg, USA). The specimens were undergone pH cycling and brushing machine and then, the average surface roughness (Ra) and average profile changes along the desired area (Rz) of the specimens were determined with profilometer instrument. Two-way and one-way analysis of variance (ANOVA) was used to compare the mean of surface roughness. Then, Tukey test was used to identify the groups responsible for the difference and t-test was used to compare the mean of surface roughness.
Results: The type of composite and the method of polishing procedure had no effect on the mean Ra (P=0.733) but it had significant effect on Rz1 factor (P=0.025).
Conclusion: Using liquid polish after polishing discs had no effect on the polish retention of nanocomposites.

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: Considering the preventive and therapeutic effects of resin infiltration (RI) and the unknown effect of bleaching on the enamel treated with this method, this in-vitro study aimed to assess the effect of bleaching on color stability of enamel lesions treated with RI.
Materials and Methods: In this in-vitro, experimental study, enamel-dentin samples measuring 5×5×3 mm were prepared on the buccal and lingual surfaces of 30 extracted humans third molars with no caries, cracks or enamel defects by a microtome. The specimens were divided into three groups of 10 specimens: 1) sound enamel (control), 2) demineralized enamel, 3) demineralized enamel plus RI. White spot lesions were artificially created by immersing the samples in hydroxyethyl cellulose demineralizing gel with a pH of 4.5 for 4 days. Next, Icon RI was applied on the samples in group 3. The baseline color of the specimens was measured using a spectrophotometer. Then, 35% hydrogen peroxide was applied on the specimens in three cycles and time interval of 10 min. After the end of the last cycle, the samples were completely washed for 1 min and then, underwent colorimetry again. Data were analyzed using one-way ANOVA.
Results: The results of this study showed that the highest level of color change (ΔE) in the demineralized group was 6.3±2.003, while the least amount of ΔE in the enamel lesion group treated with resin infiltration was 3.54±0.98 and in the control group ΔE was 4.13±1.14. Therefore, there was a significant difference between demineralized and treated by infiltratant groups (P=0.005). However, there was no significant difference between control group and treated with resin infiltration group (P=0.54).
Conclusion: Bleaching induced a less change in the color of the enamel lesions treated by resin infiltration compared with that of the demineralized teeth.
 
 

Background and Aims: The white color of teeth is one of the most essential factors in smile esthetics. Therefore, various whitening agents such as bleaching mouthwashes have been produced in response to the people’s high demand for having whiter teeth. The present study evaluated the efficacy of three whitening mouthwash products on tooth enamel whiteness.
Materials and Methods: In the present in vitro study, 32 bovine incisors were assigned to four groups in terms of the mouthwash used (n=8): control (C); Xenon Smart White (ZSW), containing pyrophosphate and triphosphate; Signal White Now (SWN), containing Blue Covarine; and Pasta Del Capitano whitening mouthrinse (PCW), containing Plasdone. Colorimetry was carried out using a spectrophotometer at the baseline and 2, 4, 8, and 12 weeks after treatment with mouthwashes. Data were analyzed using CIELab parameters with ANOVA, RM two-way ANOVA, and post hoc Tukey tests (α=0.05).
Results: The results showed that the whiteness created by the SWN mouthwash was clinically visible (ΔE>3.3). However, the functions of all the mouthwashes were statistically similar with no significant differences from the control group (P>0.05).
Conclusion: Although, Blue Covarine-containing mouthwash was somewhat effective in whitening of tooth enamel, none of the mouthwashes had significant efficacy compared to distilled water.

Background and Aims: Root canal treatment failures are often attributed to incomplete removal of bacteria, particularly Enterococcus faecalis. While, chlorhexidine and sodium hypochlorite serve as conventional treatments. herbal medicine has been today considered as an alternative to synthetic medicine due to its safety. Therefore, the aim of the present study was to compare the antibactrial effect of Scrophularia Striata extract with chlorhexidine and sodium hypochlorite on Enterococcus Faecalis in the tooth root canal. Materials and Methods: In this study, sixty extracted teeth were examined. Following the infection of dental canals with Enterococcus faecalis, materials were tested in 3 groups: 1) chlorhexidine 2% (18 teeth), 2) sodium hypochlorite 2.5% (18 teeth), and 3) Scrophularia striata (at the concentration obtained from MIC, 20%; 18 teeth). Additionally, the positive control and negative control were included (3 teeth in each group). Samples were then cultured on bile esculin agar. After 72 hours, black colonies were eaxamined. Chi-squared test was used to analyze the results. Results: Enterococcus faecalis bacteria grew in 6, 8, and 17 out of the 18 teeth within the sodium hypochlorite, chlorhexidine, and Scrophularia striata extract groups, respectively. Consequently, the bactericidal effects for sodium hypochlorite, chlorhexidine, and Scrophularia striata extract were 66.6%, 55.5%, and 5.55%, respectively.

Conclusion: The antibacterial effect of the Scrophularia striata extract was significantly lower than chlorhexidine and sodium hypochlorite on Enterococcus faecalis in dental canals viewed as a suitable replacement to the already in use synthetic therapeutic irrigants.

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: The bond strength of direct composite restoration to the caries affected dentin is a challenging issue. Preparation of dentin with an antibacterial agent is a method for creating durable bonded restorations. The aim of this study was to investigate the effect of curcumin photosensitizer on the bond strength of a universal adhesive to the caries-affected dentin (CAD).
Materials and Methods: In this experimental in vitro study, forty-four decayed human molar teeth were selected. After removing the surface enamel and dentin by a water-cooled saw, the decayed mid-coronal dentin was stained with a caries detection solution. The green and soft infected dentin was removed and CAD and hard and healthy surrounding dentin were left. Then, the remaining dentin surfaces were treated by 600 grit silicon carbide papers and polished. The specimens were divided into two groups (n=22): dentin pretreatment group by curcumin and control with no dentin pretreatment group by curcumin.  Each group was divided into two subgroups based on the method of application of All-Bond Universal adhesive (Bisco, USA) (etch and rinseand self-etching methods). After placing the Aelite All Purpose Body (Bisco, USA) composite, all  specimens  were placed in a universal testing machine for microshear bond strength (µSBS) test. The failure mode of the isolated surfaces was evaluated under a stereomicroscope. Two-way ANOVA analysis was used for statistical analysis.
Results: Based on the obtained results, intervention with the adhesive application method and surface pretreatment with curcumin had no significant effect on the bond strength. Also, there was no significant difference in the bond strength of the curcumin group in both etch and rinse and self-etching methods (SE=56.3±27.11 MPa; ER=52.4±84.11 MPa) (P=0.847). In the curcumin-free group, there was no significant difference between the two different adhesive application methods (P=0.187).
Conclusion: The results obtained in the present study showed that the pretreatment of dentin affected by caries with light-sensitive curcumin and also use of a universal adhesive by either self-etching or self-etchinf methodshad no influence on the microshear bond strength of the composite restoration.