Imaging is one of the most important tools for orthodontists to evaluate and record size and form of craniofacial structures. Orthodontists routinely use 2-dimensional (2D) static imaging techniques, but deepness of structures cannot be obtained and localized with 2D imaging. Three-dimensional (3D) imaging has been developed in the early of 1990's and has gained a precious place in dentistry, especially in orthodontics. The aims of this literature review are to summarize the current state of the 3D imaging techniques and to evaluate the applications in orthodontics.

Objective: To determine three-dimensional (3D) effects of three different rapid maxillary expansion (RME) appliances on facial soft tissues. Materials and Methods: Forty-two children (18 boys, 24 girls) who required RME treatment were included in this study. Patients were randomly divided into three equal groups: banded RME, acrylic splint RME, and modified acrylic splint RME. For each patient, 3D images were obtained before treatment (T1) and at the end of the 3-month retention (T2) with the 3dMD system. Results: When three RME appliances were compared in terms of the effects on the facial soft tissues, there were no significant differences among them. The mouth and nasal width showed a significant increase in all groups. Although the effect of the acrylic splint RME appliances on total face height was less than that of the banded RME, there was no significant difference between the appliances. The effect of the modified acrylic splint appliance on the upper lip was significant according to the volumetric measurements (P , .01). Conclusions: There were no significant differences among three RME appliances on the facial soft tissues. The modified acrylic splint RME produced a more protrusive effect on the upper lip. (Angle Orthod. 2016;86:590-598.)

Objective: To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT). Material and Methods: The study sample consisted of 100 adult patients (45 men and 55 women; mean age 5 24.0 6 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests. Results: Nasopharyngeal airway volume in the high-angle group (mean 5 6067.9 6 1693.9 mm 3

ObjectiveThis study evaluated the cytotoxicity and genotoxicity of fixed orthodontic treatment with three different light-cured orthodontic bonding composites by analyzing micronucleus (MN) formation in the buccal mucosa during a 6-month period.MethodsThirty healthy volunteers were selected from consecutive patients referred for orthodontic treatment. Equilibrium 2 brackets and molar tubes (Dentaurum) were bonded with three different light-cured orthodontic bonding composites-Transbond XT (3M Unitek), Kurasper F (Kuraray Europe), or GrenGloo (Ormco Corporation)- to all teeth in both arches. Exfoliated buccal epithelial cells were scraped from the middle part of the inner cheeks with sterile cement spatulas before treatment and at 1, 3, and 6 months after treatment. MNs and nuclear alterations, such as karyorrhexis (KR), karyolysis (KL), and binucleated cells (BNs), were scored under a light microscope. Repeated measure ANOVA was used to calculate statistical differences in degenerative nuclear abnormalities.ResultsMN rates did not significantly differ among different time points within the same cell type (p > 0.05). In contrast, the number of BNs in buccal epithelial cells significantly increased in all composite groups (p < 0.01, Transbond XT; p < 0.001, Kurasper F and GrenGloo). KL frequency significantly increased between the beginning and end of the study in the Kurasfer F (0.80 ± 0.79 to 1.90 ± 1.10; p < 0.05) and GrenGloo (1.30 ± 1.06 to 2.40 ± 1.08; p < 0.05) groups.ConclusionsAfter 6 months of fixed orthodontic treatment with different light-cured composites, morphological signs of cytotoxicity were observed but genotoxic effects were absent.

IntroductionOrthodontics is a unique science in dentistry since its workspace sets on the external surface of enamel when using fixed appliances for treatment. Orthodontists or patients may encounter unwanted changes on the enamel surface or structure, such as discoloration, white spots, microcracks, fractures, and abrasions during and after fixed orthodontic treatment (FOT) because of, e.g., diet, oral care, bonding materials and techniques, composites, appliances, debonding, and clean-up procedures (1-3). Bonding materials and composites of FOT are the most prominent factors responsible for enamel color alterations (3,4). Enamel discolorations may occur by direct absorption of food colorants and products arising from the corrosion of the orthodontic appliance into resin tags (5,6). The long-term presence of these residues in the enamel tags during fixed treatment makes the color stability of these materials critical for tooth color (7).A great deal of orthodontic research has concentrated on the assessment of the physical and mechanical performances of the adhesive resins. However, comparatively few studies have investigated the effects of bonding materials used in brackets on enamel color (3,5,8-10) and only 2 clinical studies examined the color alterations of teeth associated with FOT (3,4). According to the findings of those studies, visible enamel color changes may occur with fixed appliances, which would be detected in clinical trials (3,4). Although enamel color was changed after orthodontic treatment, the lightcured composite was associated with lower discoloration rates than chemically cured resins (4). According to Karamouzos et al. (4), orthodontists may choose the use of no-mix and light-cured composites, whose effects on enamel color were the same. However, a recent in vitro study about discoloration of these types of orthodontic composites revealed that unsatisfactory color stability was Background/aim: To determine the color alterations of natural teeth associated with different orthodontic composites used in comprehensive short-term treatment.Materials and methods: Twenty-two patients were treated with fixed appliances and 22 untreated subjects were also evaluated. Lower incisors were bonded with different orthodontic composites: 42 with Grengloo, 41 with Light Bond, 31 with Kurasper F, and 32 with Transbond XT. The color parameters of the Commission Internationale de l'Eclairage (CIE) were measured for each tooth with a spectrophotometer. Color assessment in relation to time, adhesive material, and their interaction was made with 2-way mixed analysis of variance (ANOVA) and 1-way ANOVA for the color differences (∆E*). Further analyses were done using Tukey's honestly significant difference tests and paired-samples t-tests. Results:The color of teeth was affected by treatment. The mean L* and a* values increased, whereas the mean b* values decreased. Total color differences of teeth demonstrated visible color changes clinically after treatment, ranging from 1.12 to 3.34 ∆E units. However, there w...