Retention efficacy and patient experience with customized clear retainer and wrap-around circumferential retainer among non-extraction orthodontic patients: A 12-month follow-up cohort study.

OBJECTIVE: The aim of this study was to evaluate retention efficacy by assessing retention stability and patient perspectives according to type of circumferential retainer: the wrap-around circumferential retainer (WCR) and customized clear retainer (CCR). MATERIALS AND METHODS: This cohort follow-up study involved 52 patients aged 18-62 who underwent fixed-appliance orthodontic treatment without extractions or orthognathic surgery. Following screening consenting participants were divided into WCR and CCR groups. All participants before follow-up received fixed retainers for the upper and lower anteriors and respective removable retainers within 2 weeks post-debond. Intraoral scans and lateral cephalograms were taken immediately after debonding (T0) and again 12 months later. Dentoalveolar changes in several measurements were compared to evaluate retention efficacy. Surveys were conducted at 1 month (T1) and 12 months (T2) post-debonding to assess changes in patient experiences. Outcome assessments were blinded. Paired T-tests and independent T-tests were used for intragroup and intergroup comparisons of dentoalveolar measurements, respectively. Survey responses were analysed using the Pearson Chi-Square test. RESULTS: The final assessment included 32 participants. Model analysis revealed no significant differences between the groups, except for maxillary intermolar width (p = .033). In the WCR group, the cephalometric analysis indicated a significant increase in the incisor mandibular plane angle (p = .002) and a decrease in the interincisal angle (p = .014), while changes in the CCR group were statistically non-significant. Patient attitude evaluation showed similar trends for wear time and overall satisfaction. However, a higher percentage of respondents in the WCR group reported irritation when wearing the retainers (p = .037) at T1 and discomfort related to speech (p = .038) at T2. CONCLUSIONS: CCR showed better retention efficacy in terms of lower incisor inclination. Patients experienced relatively less irritation and speech discomfort with CCRs.

Reliability and time-based efficiency of artificial intelligence-based automatic digital model analysis system.

OBJECTIVES: To compare the reliability, reproducibility, and time-based efficiency of automatic digital (AD) and manual digital (MD) model analyses using intraoral scan models. MATERIAL AND METHODS: Two examiners analysed 26 intraoral scanner records using MD and AD methods for orthodontic modelling. Tooth size reproducibility was confirmed using a Bland-Altman plot. The Wilcoxon signed-rank test was conducted to compare the model analysis parameters (tooth size, sum of 12-teeth, Bolton analysis, arch width, arch perimeter, arch length discrepancy, and overjet/overbite) for each method, including the time taken for model analysis. RESULTS: The MD group exhibited a relatively larger spread of 95% agreement limits when compared with AD group. The standard deviations of repeated tooth measurements were 0.15 mm (MD group) and 0.08 mm (AD group). The mean difference values of the 12-tooth (1.80-2.38 mm) and arch perimeter (1.42-3.23 mm) for AD group was significantly (P < 0.001) larger than that for the MD group. The arch width, Bolton, and overjet/overbite were clinically insignificant. The overall mean time required for the measurements was 8.62 min and 0.56 min for the MD and AD groups, respectively. LIMITATIONS: Validation results may vary in different clinical cases because our evaluation was limited to mild-to-moderate crowding in the complete dentition. CONCLUSIONS: Significant differences were observed between AD and MD groups. The AD method demonstrated reproducible analysis in a considerably reduced timeframe, along with a significant difference in measurements compared to the MD method. Therefore, AD analysis should not be interchanged with MD, and vice versa.

Effectiveness of remote monitoring and feedback on objective compliance with a mandibular advancement device for treatment of obstructive sleep apnea.

Compliance with a mandibular advancement device is important for the optimal treatment of obstructive sleep apnea. Recent advances in information and communication technology-based monitoring and intervention for chronic diseases have enabled continuous monitoring and personalized management. Self-evaluation and self-regulation through objective monitoring and feedback may improve compliance. The aim of this study was to evaluate the effects of information and communication technology-based remote monitoring and feedback services, using a smartphone application, on the objective compliance with a mandibular advancement device in patients with obstructive sleep apnea. Forty individuals who were diagnosed with obstructive sleep apnea by polysomnography were randomly assigned to groups A and B. During an initial 6-week evaluation period, the mandibular advancement device-wearing time was monitored with the smartphone application in group B, but not in group A. The two groups then switched the monitoring procedures during the second 6-week period (the smartphone application was then used by group B, but not by group A). If no input data were indicated on the cloud server of the smartphone application during the monitored period, push notifications were provided twice daily. Objective compliance, monitored by a micro-recorder within the mandibular advancement device, was noted and compared based on whether the monitoring service was provided. The number of mandibular advancement device-wearing days was significantly higher in the monitored period than in the unmonitored period. The mandibular advancement device-wearing time did not differ significantly between the two groups. In conclusion, information and communication technology-based remote monitoring and feedback services demonstrated a potential to increase the objective measures of compliance with mandibular advancement devices.

Accuracy of 3-dimensional printed bracket transfer tray using an in-office indirect bonding system.

INTRODUCTION: In this study, we aimed to evaluate and compare the bracket positioning accuracy of the indirect bonding (IDB) transfer tray fabricated in-clinic using the tray printing (TP) and marker-model printing methods (MP). METHODS: The TP group was further divided into 2 groups (single-tray printing [STP] and multiple-tray printing [MTP]) depending on the presence of a tray split created using the 3-dimensional (3D) software. Five duplicated plaster models were used for each of the 3 experimental groups, and a total of 180 artificial teeth, except the second molar, were evaluated in the experiment. The dental model was scanned using a model scanner (E3; 3Shape Dental Systems, Copenhagen, Denmark). Virtual brackets were placed on facial axis points, and the IDB trays were designed and fabricated using a 3D printer (VIDA; EnvisionTEC, Mich). The accuracy of bracket positioning was evaluated by comparing the planned bracket positions and the actual bracket positions using 3D analysis on inspection software. The main effects and first-order interaction effects were analyzed together by analysis for the analysis of variance. RESULTS: The mean distance and height errors were significantly lower in the STP group than those in the MP and MTP groups (P <0.05). The mean distance error was 0.06 mm in the STP group and 0.09 mm in the MP and MTP groups. The mean height error was 0.10 mm in the STP group and 0.15 mm and 0.18 mm in MP and MTP groups, respectively. However, no significant differences were observed in the angular errors among the 3 groups. CONCLUSIONS: The in-office-fabricated IDB system with computer-aided design and 3D printer is clinically applicable after considering the linear and angular errors. We recommend IDB trays fabricated using the STP method owing to the lower frequency of bracket positioning errors and ease of fabrication.

Durable Oral Biofilm Resistance of 3D-Printed Dental Base Polymers Containing Zwitterionic Materials.

Poly(methyl methacralyate) (PMMA) has long been used in dentistry as a base polymer for dentures, and it is recently being used for the 3D printing of dental materials. Despite its many advantages, its susceptibility to microbial colonization remains to be overcome. In this study, the interface between 3D-printed PMMA specimens and oral salivary biofilm was studied following the addition of zwitterionic materials, 2-methacryloyloxyethyl phosphorylcholine (MPC) or sulfobetaine methacrylate (SB). A significant reduction in bacterial and biofilm adhesions was observed following the addition of MPC or SB, owing to their protein-repellent properties, and there were no significant differences between the two test materials. Although the mechanical properties of the tested materials were degraded, the statistical value of the reduction was minimal and all the properties fulfilled the requirements set by the International Standard, ISO 20795-2. Additionally, both the test materials maintained their resistance to biofilm when subjected to hydrothermal fatigue, with no further deterioration of the mechanical properties. Thus, novel 3D-printable PMMA incorporated with MPC or SB shows durable oral salivary biofilm resistance with maintenance of the physical and mechanical properties.

Registration of digital dental models and cone-beam computed tomography images using 3-dimensional planning software: Comparison of the accuracy according to scanning methods and software.

INTRODUCTION: The registration of cone-beam computed tomography (CBCT) images and digital dental models is required for the design and manufacturing of dental devices such as implant guides and surgical wafers. This study aims to register intraoral scan (IS) models and cast scan (CS) models onto CBCT images using 3-dimensional (3D) planning software and evaluate the registration accuracy according to scanning methods and 3D planning software. METHODS: The CBCT image of an artificial skull model with reference markers was taken. The CS model and the IS model were obtained from the same skull model, registered onto the CBCT image using 3D planning software packages providing manual registration (MR) function and point-based registration (PR) functions, and set as the experimental groups. After registration, shell to shell deviations and positional differences between the reference model and the experimental models were evaluated. RESULTS: The shell to shell deviations ranged from 0.03 to 0.18 mm. Deviations in both the maxilla and mandible were significantly different according to scanning methods and software packages. In the anteroposterior direction, the IS-MR and CS-MR groups showed significantly different positions. In the superoinferior direction, the MR and PR groups showed significantly different positions. CONCLUSIONS: The registration using the PR function of the 3D planning software packages was significantly more accurate than the registration using the MR function. There was no significant difference between the registrations using the IS model and the CS model when using the PR functions.

Evaluation of dental plaque reduction using microcurrent-emitting toothbrushes in orthodontic patients: a randomized, double-blind, crossover clinical trial.

This study aimed to compare the effectiveness of microcurrent-emitting toothbrushes (MCTs) and ordinary toothbrushes in reducing the dental plaque index (PI) and dental caries activity among orthodontic patients. The evaluation was performed using a crossover study design involving 22 orthodontic patients randomly assigned to the MCT or ordinary toothbrush groups. The participants used the designated toothbrush for 4 weeks and had a 1-week wash-out time before crossover to the other toothbrush. PI (Attin's index) and dental caries activity were measured at baseline and at the end of each 4-week period. Additionally, patients completed questionnaires to assess patient satisfaction for "freshness in mouth" and "cleansing degree." The results showed that the MCT group had a significant reduction in PI (p = 0.009), whereas the ordinary toothbrush group did not (p = 0.595). There was no significant difference in the dental caries activity between the two groups (p > 0.05). Patient satisfaction assessment revealed that 65% patients in the MCT group had more than "fair" experience of freshness, in contrast to 50% of patients in the ordinary toothbrush group. Satisfaction with cleansing degree was similar in both groups. Overall, these findings suggest that MCTs are more effective in reducing dental PI than ordinary toothbrushes.

Evaluation of the effects of temperature and centrifugation time on elimination of uncured resin from 3D-printed dental aligners.

The study investigated the effects of temperature and centrifugation time on the efficacy of removing uncured resin from 3D-printed clear aligners. Using a photo-polymerizable polyurethane resin (Tera Harz TC-85, Graphy Inc., Seoul, Korea), aligners were printed and subjected to cleaning processes using isopropyl alcohol (IPA) or centrifugation (g-force 27.95g) at room temperature (RT, 23 °C) and high temperature (HT, 55 °C) for 2, 4, and 6 min. The control group received no treatment (NT). Cleaning efficiency was assessed through rheological analysis, weight measurement, transparency evaluation, SEM imaging, 3D geometry evaluation, stress relaxation, and cell viability tests. Results showed increased temperature and longer centrifugation times significantly reduced aligner viscosity, weight (P < 0.05), and transmittance. IPA-cleaned aligners exhibited significantly lower transparency and rougher surfaces in SEM images. All groups met ISO biocompatibility standards in cytotoxicity tests. The NT group had higher root mean square (RMS) values, indicating greater deviation from the original design. Stress relaxation tests revealed over 95% recovery in all groups after 60 min. The findings suggest that a 2-min HT centrifugation process effectively removes uncured resin without significantly impacting the aligners' physical and optical properties, making it a clinically viable option.

Viscoelastic and antimicrobial dental care bioplastic with recyclable life cycle.

Medical plastic-appliance-based healthcare services, especially in dentistry, generate tremendous amounts of plastic waste. Given the physiological features of our mouth, it is desirable to substitute dental care plastics with viscoelastic and antimicrobial bioplastics. Herein, we develop a medical-grade and sustainable bioplastic that is viscoelastic enough to align the tooth positions, resists microbial contamination, and exhibits recyclable life cycles. In particular, we devise a molecular template involving entanglement-inducing and antimicrobial groups and prepare a silk fibroin-based dental care bioplastic. The generated compactly entangled structure endows great flexibility, toughness, and viscoelasticity. Therefore, a satisfactory orthodontic outcome is accomplished, as demonstrated by the progressive alignment of male rabbit incisors within the 2.5 mm range. Moreover, the prepared bioplastic exhibits resistance to pathogenic colonization of intraoral microbes such as Streptococcaceae and Veillonellaceae. Because the disentanglement of entangled domains enables selective separation and extraction of the components, the bioplastic can be recycled into a mechanically identical one. The proposed medical-grade and sustainable bioplastic could potentially contribute to a green healthcare future.

Three-dimensional evaluation of a virtual setup considering the roots and alveolar bone in molar distalization cases.

We aimed to evaluate root parallelism and the dehiscence or fenestrations of virtual teeth setup using roots isolated from cone beam computed tomography (CBCT) images. Sixteen patients undergoing non-extraction orthodontic treatment with molar distalization were selected. Composite teeth were created by merging CBCT-isolated roots with intraoral scan-derived crowns. Three setups were performed sequentially: crown setup considering only the crowns, root setup-1 considering root alignment, and root setup-2 considering the roots and surrounding alveolar bone. We evaluated the parallelism and exposure of the roots and compared the American Board of Orthodontics Objective Grading System (ABO-OGS) scores using three-dimensionally printed models among the setups. The mean angulation differences between adjacent teeth in root setups-1 and -2 were significantly smaller than in the crown setup, except for some posterior teeth (p < 0.05). The amount of root exposure was significantly smaller in root setup-2 compared to crown setup and root setup-1 except when the mean exposure was less than 0.6 mm (p < 0.05). There was no significant difference in ABO-OGS scores among the setups. Thus, virtual setup considering the roots and alveolar bone can improve root parallelism and reduce the risk of root exposure without compromising occlusion quality.

Cytotoxicity, Colour Stability and Dimensional Accuracy of 3D Printing Resin with Three Different Photoinitiators.

Biocompatibility is important for the 3D printing of resins used in medical devices and can be affected by photoinitiators, one of the key additives used in the 3D printing process. The choice of ingredients must be considered, as the toxicity varies depending on the photoinitiator, and unreacted photoinitiator may leach out of the polymerized resin. In this study, the use of ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L) as a photoinitiator for the 3D printing of resin was considered for application in medical device production, where the cytotoxicity, colour stability, dimensional accuracy, degree of conversion, and mechanical/physical properties were evaluated. Along with TPO-L, two conventional photoinitiators, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), were considered. A total of 0.1 mol% of each photoinitiator was mixed with the resin matrix to prepare a resin mixture for 3D printing. The specimens were printed using a direct light processing (DLP) type 3D printer. The 3D-printed specimens were postprocessed and evaluated for cytotoxicity, colour stability, dimensional accuracy, degree of conversion, and mechanical properties in accordance with international standards and the methods described in previous studies. The TPO-L photoinitiator showed excellent biocompatibility and colour stability and possessed with an acceptable dimensional accuracy for use in the 3D printing of resins. Therefore, the TPO-L photoinitiator can be sufficiently used as a photoinitiator for dental 3D-printed resin.

Synergetic effects of solution-processable fluorinated graphene and PEDOT as a hole-transporting layer for highly efficient and stable normal-structure perovskite solar cells.

We demonstrate that a bi-interlayer consisting of water-free poly(3,4-ethylenedioxythiophene) (PEDOT) and fluorinated reduced graphene oxide (FrGO) noticeably enhances the efficiency and the stability of the normal-structure perovskite solar cells (PeSCs). With simple and low temperature solution-processing, the PeSC employing the PEDOT + FrGO interlayer exhibits a significantly improved power conversion efficiency (PCE) of 14.9%. Comprehensive investigations indicate that the enhanced PCE is mostly attributed to the retarded recombination in the devices. The minimized recombination phenomena are related to the interfacial dipoles at the PEDOT/FrGO interface, which facilitates the electron-blocking and the higher built-in potential in the devices. Furthermore, the PEDOT + FrGO device shows a better stability by maintaining 70% of the initial PCE over the 30 days exposure to ambient conditions. This is because the more hydrophobic graphitic sheets of the FrGO on the PEDOT further protect the perovskite films from oxygen/water penetration. Consequently, the introduction of composite interfacial layers including graphene derivatives can be an effective and versatile strategy for high-performing, stable, and cost-effective PeSCs.