ezatolah kazeminejad

The present in vitro study aimed to evaluate the effect of a 980 nm diode laser irradiation on the bond strength of fiber posts to intracanal dentine.

Twenty-four extracted human maxillary central incisors were obtained. After root canal treatment, the samples were randomly divided into two groups (n=12): In group 1, root canal dentin was subjected to diode laser irradiation (980 nm, 1W, continuous wave) whereas group 2 was considered the control group and was not irradiated. Fiber posts were cemented using resin cement. The pull-out bond strength of the fiber posts was assessed with a universal testing machine. The data were analyzed by an independent samples t-test (α=0.05).

The average fracture strength of the laser-irradiated group (90.04 ± 30.45 MPa) was significantly higher than the control group (62.95 ± 22.09 MPa; P = 0.021).

Diode laser irradiation to the root canal can increase the bond strength of fiber posts to intraradicular dentin.

Determination of the exact working length is one of the most important steps in root canal treatment. Various devices and methods, such as electronic apex locators, have been developed for the determination of the working length. The present study aimed to compare the accuracy of four electronic apex locators, DTE, Denjoy, Woodpecker and Coxo, in determining the actual working length.

In this descriptive study, fourty mandibular premolar teeth that fulfilled the inclusion criteria were selected and examined. First, each tooth was measured with four apex locators. The electronic measurements were performed following the manufacturers’ instructions within ±0.5 mm, ±1 mm and exactly at apical constriction. To calculate the actual working length, 4 mm of the root end was buccolingually cut from buccal side of the canal, and the distance between the coronal reference point and apical constriction was measured under a microscope. Then, data were analysed with Paired T test.

. Within ±0.5 mm from the apical constriction and at the apical constriction, the accuracy of apex locators DTE, Woodpecker, Coxo and Denjoy were 87% and 45%, 85% and 37%, 85% and 45% and 82% and 42%, respectively. All specimens measured with four types of apex locators were within the range of -1 to +1 mm to the apex with an accuracy of 97.5%.

 None of the four apex locators reported an accuracy of 100% at apical constriction. There was no statistically significant difference between the working length measured by four apex locators and the actual working length.

Oral cancer is one of the most prevailing neoplasms globally, and human papillomavirus (HPV) is one of the risk factors for this condition. Knowledge and awareness about HPV-related oral cancer can lead to a better diagnosis and prognosis of this disease. This systematic review aimed to evaluate knowledge and awareness about HPV-related oral cancer among dentists and dental students.

We searched Web of Science, Scopus, PubMed, and ProQuest databases with Medical Subject Headings (MeSH) and non-MeSH keywords to find related articles. Our eligibility criteria were: 1) cross-sectional studies including knowledge and awareness about HPV-related oral cancers, 2) publication date up to August 18, 2021, 3) studies containing dentists or dental students as the main participants, or as part of the participants. The Joanne Briggs Institute (JBI) checklist was used for quality assessment.

A total of 10 studies were included in this systematic review. Five studies have shown that over 80 percent of dental students know HPV can cause oropharyngeal cancer (OPC). More than three-quarters of dentists reported HPV as a cause of oral cancer. Less than half of patients in two studies mentioned biopsy for adequate diagnosis.

HPV-related oral cancer knowledge and awareness need to be improved through focusing on academic and public education. For dental students, it is necessary to identify HPV as a risk factor for oral cancer. Moreover, the significance of routine checkups should not be ignored.

This study assessed the antimicrobial effects of different concentrations of simvastatin versus triple antibiotic paste (TAP) on Enterococcus faecalis biofilms at different stages of development.

 In this in vitro study, 70 human single-rooted mature premolars were decoronated, instrumented, and autoclave-sterilized. Next, an E. faecalis suspension was prepared and inoculated into the canals to obtain 4- and 6-week biofilms. After ensuring biofilm formation, the samples in each group were randomly assigned to 5 subgroups (n=12): 1 mg/mL TAP, 10 mg/ mL TAP, 1 mg/mL simvastatin, 10 mg/mL simvastatin, and positive control (phosphate-buffered saline solution). The medicaments were applied in the canals, and the teeth were incubated for one week. Dentin samples were collected by a rotary file, cultured, and the number of E. faecalis colonies was counted. The Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests were used for data analysis (α=0.05).

There were significant differences in colony counts between the two concentrations of TAP and the control group against both 4- and 6-week biofilms (P<0.05). The antibacterial effect of 10 mg/mL TAP and simvastatin was stronger than that of 1 mg/mL concentration against the 4- and 6-week E. faecalis biofilms (P<0.05). Furthermore, 10 mg/mL TAP and simvastatin were more effective against the 4-week biofilms than the 6-week biofilms (P<0.05).

According to the present results and since biofilms may remain viable in the root canal system for weeks to months, applying 10 mg/mL TAP and simvastatin might be more effective.

Bacterial disinfection is considered as the primary etiology of pulpal and periapical lesions and as the result, adequate elimination of such infections is one of the purposes of root canal treatment; But since this purpose is impossible to achieve, reducing the bacterial load seems to be as a rational goal. Diode lasers have made their way into endodontics for better disinfection and penetration into the root canal dentine. This study reports 3 cases of Diode laser assisted endodontic treatments in periapical lesions repair.

Case Report:

 3 patients referred to an endodontist for root canal treatment and 2 patients were treated with diode laser (wavelength of 940 nm and power output of 1W) and one patient was treated with diode laser (wavelength of 810 nm and power output of 1 W). The follow-up outcomes for all three patients showed the treatment success.

Diode laser can be used in root canal treatment of teeth with periapical lesions.

Lasers and optics have been used extensively in dental procedures in recent years, and realizing the optical properties of the tooth is also an essential in its successful applications. The aim of this study was to compare the absorption and transmission of applied wavelengths in the range of 190–1100 nm at different dentin thicknesses and the effect of changing the direction of radiation emission on the dentin tubules.

There were fifteen dentin specimens with thicknesses of 300, 600, and 1000 mm, five specimens for each thickness, prepared through a transverse section of the coronal dentin over the pulpal roof area of human molars. Considering the coronal-apical and apical-coronal directions, we measured the absorption and transmission of parallel light rays perpendicular to the dentin samples in different thicknesses and two directions with a Cecil CE 7400 UV/Vis spectrometer. Data analysis was performed using SPSS software version 19. P value < 0.05 was considered significant.

The absorption rate of the ultraviolet wavelength range was significantly higher than that of visible and infrared light irradiation from both directions at three thicknesses (P < 0.001). The radiation shift direction had no significant differences in the absorption and transmission of wavelengths of ultraviolet, visible, and infrared light in any of the three thicknesses (P > 0.05).

Accordingly, attenuation or transmission losses of light in the ultraviolet to infrared range clearly depend on the wavelength of light and the optical properties of dental dentin, and the thickness of the dentin used in this study has a little effect.

The COVID-19 outbreak has led to increasing global concerns about infection control. Amid this pandemic, dentistry could be considered as one of the most high-risk medical sectors for health workers due to the high exposure to patients infected with this deadly virus.After the decline of the steep prevalence of COVID -19 cases, the dental associations have allowed dental offices to reopen under special circumstances by taking the necessary precautions and following the prescribed guidelines to keep both the dentists and their patients safe and healthy during the treatment.The aim of this review is to present a policy to manage and facilitate the dental procedures in the dental practice routine amid coronavirus by focusing on the patients’ risk level in order to keep the possibility of COVID -19 transmission to a minimum.