The aim of this study was to evaluate the relationship between skeletal sagittal nasal profile morphology and sagittal skeletal malocclusions. Regarding lateral cephalometric films, the study was conducted in a total of 135 individuals without any prior orthodontic treatment (mean age of 17.91 ± 1.91), including 49 males (mean age 17.91 ± 1.16) and 86 females (mean age 17.78 ± 1.91 years). The groups were divided into two groups as male and female according to gender, and three groups as skeletal Class 1, Class 2, and Class 3 according to the Steiner’s ANB angle. In addition, skeletal groups were compared within groups by dividing into two groups of male and female. A total of eight parameters, three skeletal sagittal angular (SNA, SNB, and ANB angles), four nasal linear (R-A, N-A, N-ANS, and N-R distances) and one nasal angular (N1-N2/N2-R angle), were measured on each cephalometric film. The arithmetic mean and standard deviation of all measured nasal parameters were calculated. For statistical analysis, independent sample t-test and one-way analysis of variance (One-Way ANOVA) were used for normally distributed data, and Mann Whitney U and Kruskal Wallis tests were used for data that did not show normal distribution. For statistical analysis, p < 0.05 was considered significant. R-A, N-A, and N-ANS linear nasal parameters differed significantly between the male and female groups, which were evaluated regardless of the skeletal groups, with a higher rate in males (p < 0.05). N-R linear nasal parameter showed a statistically significant difference between skeletal malocclusion groups, which were evaluated regardless of gender. N-R distance was found to be significantly longer in skeletal Class 3 individuals than in Class 1 and 2 individuals (p < 0.05). There was no statistically significant difference in nasal bone concavity angle in all groups (p > 0.05). R-A and N-A linear nasal parameters showed statistically significant differences between male and female sex groups in all skeletal malocclusion classes (p < 0.05). At first, results showed that males had longer measurements than females in all linear nasal parameters. Second, longer measurements were found in all linear nasal parameters in skeletal Class 3 individuals than those in skeletal Class 1 and Class 2 individuals. Third, the nasal bone concavity angle was greater in skeletal Class 2 individuals than the others.

The aim of this study was to compare the demineralizations of the enamel surfaces around different types of orthodontic brackets in an artificial cariogenic environment. A total of 90 extracted human maxillary first premolar teeth were used in this in vitro study. The teeth were divided into 6 groups, 5 study and 1 control, each consisting of 15 samples. Victory metal, Gemini metal, Clarity self-ligating ceramic, APC Clarity Advanced ceramic and Clarity Advanced ceramic brackets (3M Unitek, Monrovia, Calif) used in the study groups were bonded to the teeth with the direct technique. The gingival, occlusal and proximal enamel surfaces adjacent to the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany) (T0). Then, the teeth were placed in a cariogenic suspension environment containing Streptococcus mutans, sucrose and artificial saliva. The teeth were removed from the cariogenic suspension at the end of 28 days. Enamel surfaces were remeasured with DIAGNOdent and the values were recorded (T1). Whether the obtained data were homogeneously distributed or not was determined by the Kolmogorov–Smirnov test, within-group comparisons were performed with the Wilcoxon test, and between-group comparisons were performed with Mann–Whitney U and Kruskal–Wallis tests. Significance level was accepted as p < 0.05. In all groups, the demineralization values of the enamel surfaces in the gingival, proximal and occlusal surfaces adjacent to the brackets were significantly higher in the T1 period than in the T0 period (p < 0.05). In the T1 period of Gemini metal, Clarity self-ligating ceramic and Clarity advanced ceramic bracket groups, the demineralization values of the proximal enamel surfaces were found to be significantly higher than the Victory metal and APC Clarity Advanced ceramic bracket groups (p < 0.05). In the T1 period, the demineralization values of the occlusal enamel surfaces of the Victory metal, APC Clarity Advanced ceramic bracket groups and control group were significantly lower than the Gemini metal, Clarity self-ligating ceramic and Clarity Advanced ceramic bracket groups (p < 0.05). Significant increases in enamel demineralization values were observed as a consequence of increased retention areas for microbial dental plaque on enamel surfaces adjacent to the bracket. Considering the importance of minimizing enamel demineralization in fixed orthodontic treatments, less enamel demineralization in Victory metal and APC Clarity Advanced ceramic bracket groups showed that these brackets can be preferred in patients with poor oral hygiene.

Bracket failure is one of the most important problems encountered during fixed orthodontic treatment. For this reason, different types of adhesive agents have been developed over the years. Consequently, the aim of this study was to evaluate the shear bond strength of brackets bonded to teeth etched with a conventional acid etching method in a laboratory environment by using different types of adhesive agents and comparing the number of shear strokes. Sixty human maxillary premolars were divided into three groups and Gemini stainless steel metal brackets (3M Unitek, Monrovia, CA, USA) were bonded to all teeth. In Group 1, Transbond™ XT Primer (3M Unitek, Monrovia, CA, USA) and Transbond™ XT Light Cure Adhesive Paste composite (3M Unitek, Monrovia, CA, USA) were used. In Group 2, BracePaste® MTP Primer (American Orthodontics, Sheboygan, CA, USA) and BracePaste® Adhesive composite (American Orthodontics, Sheboygan, WI, USA) were used. In Group 3, Ortho Solo™ Primer (Ormco, Orange, CA, USA) and Grengloo™ Adhesive composite (Ormco, Brea, CA, USA) were used. The samples were subjected to a shear test with a closed-loop controlled, low-cycle fatigue machine with a capacity of 10 N and a crosshead speed of 300 mm/min. The number of shear strokes of the brackets was recorded. According to the Kruskal–Wallis and Mann–Whitney U tests performed on the data obtained, statistically significant differences were found between the groups in terms of the numbers of shear strokes (p < 0.05). Significantly higher numbers of shear strokes and higher shear bond strengths were observed in Group 3 compared with Group 1 and Group 2 (p < 0.05). There was no statistically significant difference between the numbers of shear strokes for Group 1 and Group 2 samples (p > 0.05). To conclude the study, it was observed that the type of adhesive used had an effect on the bond strength of the bracket and that the Grengloo™ adhesive agent showed higher shear bond strength. It was observed that BracePaste® Adhesive and Transbond™ XT Light Cure Adhesive Paste adhesive agents had similar shear bond strengths.

(1) Objective: The aim of this study was to compare the demineralization around brackets bonded with different types of adhesive agents in a cariogenic suspension environment. (2) Methods: In the study, 60 extracted upper first premolar teeth were divided into three groups with 20 teeth in each group. In Group 1, Transbond XT Primer + Transbond XT Light Cure Adhesive (3M Unitek, Monrovia, CA, USA), in Group 2, GC Ortho Connect Light Cure Adhesive (GC Crop, Tokyo, Japan) and in Group 3, Transbond™ Plus Self Etching Primer + Transbond XT Light Cure Adhesive (3M Unitek, Monrovia, CA, USA) adhesive agents were used. In Group 1 and 2, buccal enamel surfaces were etched for 30 s, washed for 15 s and dried for 15 s. All groups were bonded with Gemini metal (3M Unitek, Monrovia, CA, USA) brackets. Gingival, occlusal and proximal enamel surfaces of the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany), and demineralization values were recorded. Measurements were performed after bracketing (T0) and after 28 days in a cariogenic environment (T1), which was renewed every 48 h. The Kolmogorov–Smirnov test was used to determine whether or not the data were homogeneously distributed, the Wilcoxon test was used for comparisons within groups, and the Mann–Whitney U and Kruskal–Wallis tests were used for comparisons between groups. (3) Results: In all groups, demineralization values on all enamel surfaces of the brackets were found to be statistically significantly higher in the T1 period than in the T0 period (p < 0.05). In the T1 period, demineralization values of occlusal enamel surfaces in Groups 1 and 2 were found to be significantly higher than in Group 3 (p < 0.05). The amount of increase in occlusal enamel surface demineralization value between T0 and T1 periods in Groups 1 and 2 was significantly higher than in Group 3 (p < 0.05). There was no statistically significant difference in demineralization values of proximal and gingival enamel surfaces between the groups in the T1 period (p > 0.05). (4) Conclusion: Significantly less occlusal enamel surface demineralization was observed in teeth in which the Transbond™ Plus Self Etching Primer adhesive agent was not applied with acid etching.

(i) Objective: The present study aimed to compare the electrochemical corrosion resistance of six different types of fixed lingual retainer wires used as fixed retention appliances in an in vitro study. (ii) Methods: In the study, two different Ringer solutions, with pH 7 and pH 3.5, were used. Six groups were formed with five retainer wires in each group. In addition, 3-braided stainless steel, 6-braided stainless steel, Titanium Grade 1, Titanium Grade 5, Gold, and Dead Soft retainer wires were used. The corrosion current density (icorr), corrosion rate (CR), and polarization resistance (Rp) were determined from the Tafel polarization curves. (iii) Results: The corrosion current density of the Gold retainer group was statistically higher than the other retainer groups in both solutions (p < 0.05). The corrosion rate of the Dead Soft retainer group was statistically higher than the other retainer groups in both solutions (p < 0.05). The polarization resistance of the Titanium Grade 5 retainer group was statistically higher than the other retainer groups in both solutions (p < 0.05). As a result of Scanning Electron Microscope (SEM) images, pitting corrosion was not observed in the Titanium Grade 1, Titanium Grade 5 and Gold retainer groups, while pitting corrosion was observed in the other groups. (iv) Conclusion: From a corrosion perspective, although the study needs to be evaluated in vivo, the Titanium Grade 5 retainer group included is in this in vitro study may be more suitable for clinical use due to its high electrochemical corrosion resistance and the lack of pitting corrosion observed in the SEM images.