BackgroundClear aligner therapy is gaining traction owing to its esthetics and comfort. Although most aligners use thermoforming, 3D printing offers advantages such as higher accuracy and reduced waste. While literature on the properties of some 3D-printed aligner materials compared to thermoformed ones is available, a comprehensive study is currently lacking that compares all three materials (iLuxclear (LC), Graphy Clear Aligner (GY), and RightBio Clear Aligner (RD)) with thermoformed materials, particularly regarding optical and biofilm adhesion characteristics.MethodologyThree 3D direct-printed materials (LC, GY and RD) and two thermoformed materials (easyDu (ED) and Biolon (SC)) were tested. Surface morphology was analyzed by stereomicroscopy. Surface roughness (Ra) was measured at baseline (0 day) and after 45 days of immersion in artificial saliva. Light transmittance and color stability (ΔE00) were evaluated after 7 and 14 days of aging in saliva, black tea, and coffee. Bacterial adhesion was quantified using Streptococcus mutans (S. mutans) at baseline and after 3 and 7 days.ResultsThe 3D direct-printed aligners, particularly the LC group, exhibited increased surface morphology irregularities and significantly higher Ra values than the thermoformed materials; Ra increased after 45 days of immersion in artificial saliva across all groups. The thermoformed materials maintained stable color integrity, while the 3D-direct printed materials varied in performance. GY demonstrated a uniform surface structure, lower roughness, and the highest color stability, whereas LC and RD experienced significant discoloration. The RD group exhibited significantly higher S. mutans adhesion, whereas the thermoformed materials exhibited superior biofilm resistance. Notably, GY achieved comparable S. mutans adhesion to the thermoformed materials after a 7-day culture.ConclusionsAmong the 3D direct printed aligners, GY achieved comparable surface and microbiological performance to conventional options. These findings underscore their potential for balancing esthetics, susceptibility to bacterial adhesion, and clinical performance in clear aligner therapy.

BackgroundTo evaluate the effectiveness of a novel bioactive adhesive composite—comprising chitosan (CS), nanohydroxyapatite (nHA), β-tricalcium phosphate (β-TCP), and postbiotics—in enhancing the stability of orthodontic miniscrews immediately reinserted following failure in the same insertion site using a new miniscrew in an in vivo rat femur model.MethodologyComposite adhesives were prepared in two distinct forms: foam and paste. Orthodontic miniscrews were placed into the left femurs of 28 male Sprague‒Dawley rats, and a small hole was drilled 15 mm distal to the miniscrew site. Orthodontic force was applied via a 100-gram Ni‒Ti closed coil spring attached between the miniscrew and the drilled hole. After 4 weeks, the rats were divided into four groups: Group 1 (4-week control), Group 2 (8-week control), Group 3 (paste adhesive), and Group 4 (foam adhesive). Group 1 rats were euthanized to assess primary miniscrew stability. Groups 2, 3, and 4 underwent a second surgery in which miniscrews were carefully removed and reinserted without adhesive, with paste-form adhesive, and with foam-form adhesive, respectively. After an additional 4 weeks, miniscrew stability was evaluated through histological analysis and mechanical pull-out testing. The data were analyzed via one-way ANOVA followed by Duncan’s post hoc test. Normality was confirmed with the Shapiro‒Wilk test, and effect sizes (Eta Squared) were calculated due to the small sample size.ResultsReinsertion without adhesive reduced the stability of miniscrews. However, when adhesive was used during reinsertion, the maximum force required to extract the miniscrew from the surrounding bone significantly increased, with the foam group demonstrating the highest pull-out strength (PS). Compared with the control group, the paste and foam groups presented greater mean bone‒implant contact (BIC) and bone volume (BV) values, although these differences were not statistically significant (p > 0.05). Effect size analysis revealed large differences in the clinical effects of BV and PS between the control groups and the adhesive-treated groups.ConclusionsThe bioactive adhesive composite can improve the primary stability of orthodontic miniscrews immediately reinserted into the same site after failure. The findings suggest that such adhesives may serve as a temporary adjunct to support anchorage continuity, warranting further in vivo evaluation before clinical application.