RESUMO
Aim Rotation of the mandibular premolars during aligner treatment is a difficult movement to achieve accurately. The purpose of this study is to compare the effects of different attachment types and positions used in clear aligner treatments on the rotation movement and retention of clear aligners in the rotated first premolar teeth. The study also addressed the stress values in periodontal ligaments (PDLs) with finite element analysis. Materials and methods For purposes of this research, we created a mandibular tooth model and modeled the premolar tooth with a 30° rotation. Twelve separate groups were created by attaching horizontal rectangular, vertical rectangular, ellipsoid, and semi-ellipsoid attachments to the premolar tooth in buccal, lingual, and combined buccal and lingual ways. A model without attachments was created to be used as the control group. An activation movement of 0.25 mm was applied to the first premolar tooth in all 12 models. The study evaluated clear aligner displacement, von Misses stress on the PDL, and tooth displacements using the finite element stress analysis method. Results It was found that the group with horizontal rectangular attachments placed on both the buccal and lingual sides had the highest stress value in the PDL (0.1971 MPa) and the highest displacement in the tooth (0.1267 mm). Conversely, the group with semi-ellipsoid attachments placed both buccally and lingually had the least displacement movement in clear aligners (0.1441 mm). Conclusion The results indicate that groups with attachments provided better retention than groups without attachments. Models with horizontal, rectangular attachments showed significantly more tooth displacement compared to other models. Horizontal rectangular attachments placed buccally and lingually combined to provide tooth movement in rotated mandibular first premolars can be recommended for clinical use.
RESUMO
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.