Evaluation and comparison of antifungal effect of voriconazole with nystatin on candida species derived from neoplastic patients undergoing maxillofacial radiotherapy.

Background: Radiotherapy is a common treatment for head-and-neck malignancies and causes complications such as oral candidiasis and the change of oral Candida species from albicans to nonalbicans. Voriconazole has acceptable antifungal effect. The aim of this study was to determine and compare the antifungal effect of nystatin with voriconazole on these species. Materials and Methods: The samples used in this in vitro study were identified by polymerase chain reaction-restriction fragment length polymorphism from patients before and 2 weeks after head-and-neck radiotherapy in Seyed Al-Shohada Hospital. The antifungal effect of nystatin and voriconazole was determined by microdilution method and measurement of the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration, and the results were analyzed by Mann-Whitney analysis. Results: The results showed that all species before and after radiotherapy showed 100% sensitivity to nystatin. Prior to radiotherapy, 57.1% of albicans species isolated were in the sensitive range (MIC ≤1) and 42.9% were in the dose-dependent range (MIC = 2) to voriconazole. After radiotherapy, 58.3% of albicans species were in the sensitive range and 41.7% of these species were in the dose-dependent range to voriconazole. Conclusion: The results of the present study showed that before radiotherapy, all species were sensitive to nystatin, while a percentage of albicans and nonalbicans were resistant to voriconazole. In the 2nd week of radiotherapy similar to prior to radiotherapy, all species isolated from patients were sensitive to nystatin, while a percentage of albicans and nonalbicans were resistant to voriconazole.

The Effect of Bonding Surface Design on Shear Bond Strength of 3D-Printed Orthodontic Attachments.

Introduction: This study compared the shear bond strength (SBS) of four innovative designs of the bonding surface of 3D-printed orthodontic attachments with conventional mesh design. Methods: In this in vitro study, the bonding surface design in different groups was as follows: Group 1, flat surface without any feature as a negative control; Group 2, concentric circles with no cuts; Group 3, concentric circles with 16 radial cuts; Group 4, concentric circles with 32 radial cuts; Group 5, small cones with a flat end and rounded edges; Group 6, mesh-based commercially available metal brackets of the maxillary central incisor (standard edgewise, Dentaurum®) as a positive control (n = 20). In Groups 1-5, attachments were designed with SolidWorks® Software and printed with a 2K DLP-LCD printer with hard tough resin (eSun®). All the samples were bonded to the restorative composite resin (Solafil®) surfaces with orthodontic composite resin (CuRAY-ECLIPSE®). The samples were examined for SBS with a universal testing machine after thermocycling (1,000 cycles of 5‒55°C). Data were analyzed with Shapiro-Wilk, one-way ANOVA, and Bonferroni tests. The statistical significance level was set at 0.05. Results: The mean SBS was significantly different between all the groups (P < 0.001) except for Groups 2 and 5 (P = 1.00) and Groups 2 and 6 (P = 1.00). Group 4 had the highest mean of SBS. Conclusion: The bonding surface design significantly influenced the SBS of orthodontic attachments. The concentric circles with 32 cuts had higher bond strength than other designs and can be suggested as a new bonding surface design for orthodontic attachments.

Comparison of oral candidiasis characteristics in head-and-neck cancer patients before and during radiotherapy.

Background: Patients undergoing head-and-neck radiotherapy are susceptible to Candida colonization and infection. This study aimed to identify oral Candida species type (ST), colony count (CC), and oropharyngeal candidiasis (OPC) in head-and-neck cancer patients, undergoing radiotherapy, before and 2 weeks after radiation. Materials and Methods: In this quasi-experimental study, head-and-neck cancer patients undergoing radiotherapy (up to 6000 cGy) were recruited. Samples were taken before and 2 weeks after radiation therapy (RT). CC was assigned using Sabouraud dextrose agar culture medium and morphological studies were performed to confirm OPC. For identification, polymerase chain reaction-restriction fragment length polymorphism was performed. Data were analyzed using Chi-square-test and kappa coefficient. P < 0.05 was considered statistically significant. Results: Twenty-one of 33 patients were Candida positive. The detected fungal species included Candida albicans (60%), Candida tropicalis (22%), Candida glabrata (9%), and other species (9%). Following RT, OPC and CC changed significantly (P = 0.003 and P = 0.001, respectively), whereas ST did not significantly change (P = 0.081). Two new species (Candida krusei and Candida parapsilosis) were detected after the intervention. The OPC, CC, and ST changes after RT were not significantly related to malignancy site or radiation dose (P > 0.05). Conclusion: The present study showed that OPC, CC, and ST were not related to the malignancy site. Following RT, OPC and CC changed significantly, while ST showed no significant change. The radiation dose and malignancy site had no effects on the OPC, CC, or ST alterations following RT.

Bonding Surface Designs in Fixed Orthodontic Attachments.

Fixed orthodontic attachments/appliances work as a medium to transfer the force applied to the teeth. In bonded types, several factors affect the attachment bond strength and their clinical success. The primary approach for increasing the bond strength focused on altering the time and concentration of acid etching; however, the results showed that these changes might increase susceptibility to enamel decalcification. The bonding mechanism of orthodontic attachments may be chemical, mechanical, or a combination of both. Most attachment bonding surfaces (ABSs) have no chemical bond to resin composites. Hence, mechanical retention plays a major role. Developing more bonding surfaces by increasing the macroscopic size of the attachments has esthetic and hygienic limitations, so the ABS design plays a more important role in maintaining and improving the bond strength. In this research, different ABS designs are reviewed and categorized according to manufacturing methods and their features.

The Role of High-density Lipoprotein in Oral and Dental Diseases.

High-density lipoprotein (HDL) is the smallest and densest of the lipoproteins. Beyond its well-known cardiovascular protective function, it has other actions, including structural function, anti-inflammatory, antioxidant, anti-thrombotic effects, transport of bioactive molecules, and induction of signal transduction pathways. Further, there is a mutual connection between oral health and general health. Hence HDL could be a potentially crucial factor relating oral health to general health. As far as we know, no comprehensive study has been carried out to date, which has explored the association between HDL concentration and oral diseases including lichen plan, recurrent aphthous ulcers, candidiasis, implant osseointegration, oral cancer and precancerous conditions. Here in this review, we summarized the relationship between HDL and oral health, suggesting a significant association between HDL concentration and oral health.

Comparison of the antifungal effect of voriconazole and fluconazole on oral candidiasis before and during radiotherapy.

Background: Head-and-neck radiotherapy can change oral Candida species and cause candidiasis resistance to common antifungals by making the changes to the oral cavity environment. Voriconazole is a synthetic azole with extensive antifungal activity. The current study aimed at comparing the antifungal activity of fluconazole and voriconazole on Candida species isolated from the oral cavity of patients undergoing head-and-neck radiotherapy. Materials and Methods: The present in vitro study was performed on samples isolated from patients undergoing head-and-neck radiotherapy, before and during radiotherapy. After the identification of the species, the antifungal effect of fluconazole and voriconazole was determined by the microdilution method, and the minimum inhibitory concentration (MIC), the minimum fungicidal concentration, and the antifungal susceptibility of the isolated strains were also measured. The data were analyzed by the Chi-squared and then two-sided Fisher's exact tests. P < 0.05 was considered statistically significant. Results: The study findings showed no significant difference in the susceptibility of Candida albicans to voriconazole and fluconazole before and during radiotherapy. Before radiotherapy, both voriconazole and fluconazole had similar effects on Candida tropicalis, but after radiotherapy, voriconazole was less effective. However, both before and during radiotherapy, fluconazole had a greater antifungal effect than voriconazole on Candida glabrata strains. The MICs of voriconazole and fluconazole for both Candida parapsilosis and Candida krusei isolates were within the susceptible or dose-dependent range. Conclusion: The current study results showed that voriconazole was not more effective than fluconazole in the treatment of oral candidiasis in patients undergoing head-and-neck radiotherapy.

Inhibitory effects of ethanolic, methanolic, and hydroalcoholic extracts of olive (Olea europaea) leaf on growth, acid production, and adhesion of Streptococcus mutans.

BACKGROUND: Usage of chemical mouthwashes for controlling dental caries can end to some side effects such as oral biological imbalance. Recently, using natural derivatives such as herbs, presented to overcome such adverse effects. Due to antibacterial property of olive leaf extracts (Olea europaea), this study conducted in order to evaluate bacteriocidal, anti-acid production, and anti-adhesion effects of olive leaf ethanolic, methanolic, and hydroalcoholic extracts on Streptococcus mutans. MATERIALS AND METHODS: In this in vitro study, nine strains of S. mutans (PTCC1683) were used. Maceration methods were done in order to provide the olive leaf ethanolic, methanolic, and hydroalcoholic extracts. The antibacterial activities evaluated by macrodilution and disc diffusion method in different concentrations (3.25%-100%). Acid production and adhesion of bacterial strains also were evaluated. The obtained data were analyzed by analysis of variance method using SPSS software. P < 0.05 was considered as statistically significant. RESULTS: The minimum inhibitory concentration and minimum bactericidal concentration for ethanolic, methanolic, and hydroalcoholic olive leaf extracts on S. mutans are 12%-25%, 50%-75%, and 12%-25%, respectively. In addition, inhibition zone of S. mutans significantly increased in higher concentration (ethanolic and methanolic extracts: P = 0.004; hydroalcoholic extract: P = 0.003). The acid production and adhesion significantly decreased by increase in the concentration (P < 0.001). CONCLUSION: In general, olive leaf ethanolic, methanolic, and hydroalcoholic extracts induce growth inhibition, acid production, and adhesion of S. mutans. Consequently, it can be used as a natural preservative in the food industry, as well as in the production of commercial products such as chewing gum, chocolate, and toothpaste to prevent dental caries.