Antibacterial effects of nanoparticles, composite quantum dots and silk proteins attached to dental titanium alloy.

PURPOSE: To present the antibacterial effect of new generation boron-doped carbon quantum dots (B-CQD) and compare the antibacterial effect of silk sericin (SS), hydrolyzed silk peptide (HSP) and SS/HSP coated silver nanoparticle (AgNP) and B-CQDs on titanium alloy (Ti) surfaces. METHODS: SS and HSP were formed on the surface of the Ti alloy (Ti-SS/HSP). Different concentrations of citric acid and boric acid, B-CQDs and AgNP were attached to Ti-SS/HSP surfaces. To characterize all samples, Fourier Transform Infrared (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analyses were performed. Their antibacterial potential was analyzed against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Pseudomonas aeruginosa (P. aeruginosa) with Mueller-Hinton Test. One-way ANOVA was used to assess any difference between groups. P< 0.05 was considered statistically significant. RESULTS: No antibacterial activity was detected for Ti and SS/HSP. Inhibition holes ranged from 11 mm to 25.7±3.2 mm and 11 mm to 26.3±0.6 mm in the S. aureus and P. aeruginosa cultures respectively, showing that AgNP was the molecule which had the least antibacterial effect regardless of type of bound silk protein on both bacteria, and B-CQD had antibacterial superiority against S. aureus and P. aeruginosa on Ti-SS surfaces. CLINICAL SIGNIFICANCE: The application of boron-doped carbon quantum dots to titanium alloy surfaces is a new approach for the development of a powerful bactericidal method to prevent implant failures.

Evaluation of bisphenol release of different clear aligner materials using the liquid chromatography-mass spectrometry/mass spectrometry method.

OBJECTIVES: To evaluate the bisphenol release of different brands of clear aligner materials. MATERIALS AND METHODS: Six different clear aligner materials were used in this study: Duran (Scheu-Dental GmbH, Iserlohn, Germany), Zendura Flx (Bay Materials LLC, Fremont, CA, USA), Zendura A (Bay Materials), Essix (Raintree Essix Inc., Metairie, LA, USA), Taglus Premium (Laxmi Dental Export Pvt. Ltd, Mumbai, India), and Smart Track (Align Technology, San Jose, CA, USA). The samples were kept in saline solution for 8 weeks in airtight test tubes at 37°C. The ratio between the weights of the samples and the volumes of the dilutions was prepared as 0.1 g/mL as suggested by International Standards Organization parameters. To evaluate the bisphenol release of materials, liquid chromatography-mass spectrometry/mass spectrometry analysis was performed. Data were analyzed with the Kruskal-Wallis test (α = 0.05). RESULTS: Bisphenol A (BPA) values in Smart Track were found to be significantly higher than the Zendura A and Zendura Flx groups (P = .02, P = .03, respectively). There was no statistically significant difference among the samples in terms of Bisphenol F (BPF) values (P = .108). In terms of Bisphenol S (BPS) values, a statistically significant difference was found (P = .002) indicating that Smart Track released significantly more BPS than Zendura A (P = .001). CONCLUSIONS: Under the test conditions, the amounts of leached BPA, BPF, and BPS were less than the reference dose for daily intake. However, the cumulative effect of these appliances should not be underestimated.

Effects of Rapid Maxillary Expansion on the Temporomandibular Joint: A Bone Scintigraphy Study.

OBJECTIVE: The purpose of this study is to assess the effects of rapid maxillary expansion on metabolic activity in the temporomandibular joints of young adult patients using scintigraphy. METHODS: The images belonging to temporomandibular joints were obtained from the retrospective scintigraphic records taken from 17 adult females (16.1 and 18.8 years of age and the mean age was 17.3±0.86 years) who had non-functional bilateral posterior crossbite, deep palatal vault and dental crowding, and had been treated with rapid maxillary expansion. Bone scintigraphy images were collected at three-time intervals: at the beginning of treatment (T1), during the opening of the mid palatal suture (T2), and at the end of screw activation (T3). Alteration in bone activity in the temporomandibular joint regions were evaluated in sagittal and transaxial slices. To determine the differences between the intervals, repeated analysis of variance and Bonferroni multiple comparison tests were applied. RESULTS: In the right and left temporomandibular joint regions, significantly increased metabolic activity was exhibited between T1-T2 (p<0.001). At the time of opening the maxillary mid-palatal suture, the metabolic activity increased approximately 60% compared to the initial status. At the end of the active expansion period (T3), the change in metabolic activity was approximately 20% reduced compared to T2. CONCLUSION: Metabolic activity intensification occurs in the regions of interest in the temporomandibular joint during rapid maxillary expansion. After mid-palatal suture opening, activity noticeably decreased (T2-T3). This decrease in bone activity suggests that the temporomandibular joint complex adapts to rapid maxillary expansion forces.