Combining a CAD-CAM composite resin palatal wall with a direct composite resin layering technique for the restoration of a large Class IV fracture: A clinical report.

This clinical report presents combining a computer-aided design and computer-aided manufacturing (CAD-CAM) composite resin palatal wall with a direct composite resin layering technique for the esthetic and functional restoration of a large Class IV fracture of a maxillary central incisor to achieve optimal esthetic and functional outcomes.

Is dynamic occlusal design necessary for anterior guidance recovery in the computer-aided design process? An in vitro study.

OBJECTIVES: This study aimed to assess the effectiveness of patient-specific motion in restoring anterior guidance and to investigate the influence of occlusal plane position within a virtual articulator on the design of the anterior guide slope for incisors. METHODS: Twenty participants' intraoral scan, occlusal plane position, and jaw motion data were recorded. The maxillary anterior teeth were virtually prepared, and the crowns were designed based on average virtual articulator (AVR), personalized virtual articulator (ART), and patient-specific motion (PSM). The anterior guide slope of maxillary central incisors (S1, S2, Sc, Sp) and the mesio-distal angle (MDA) of the canine of prostheses were compared to that of natural teeth (NAT). One-Way ANOVA was utilized to evaluate the effectiveness of the three methods in restoring the anterior guidance of maxillary anterior teeth. RESULTS: The comparison of Sp and MDA showed no significant difference between the PSM and NAT groups (p > 0.05). However, Sp of the ART group was significantly smaller, while MDA was higher than that of the NAT group (p < 0.05). Sp did not differ significantly (p > 0.05) when the angle of the occlusal plane (AOP) was small. As the AOP increased, Sp of the ART and AVR groups were significantly smaller than that of the NAT group (p < 0.05). With a large AOP, Sp of the ART group was notably smaller than that of the NAT group (p < 0.05), while there was no significant difference between the AVR and NAT groups (p > 0.05). CONCLUSIONS: Occlusal design based on patient-specific motion proved more effective in restoring natural anterior guidance. The anterior guidance of prostheses designed using a virtual articulator was influenced by occlusal plane position. CLINICAL SIGNIFICANCE: The utilization of a jaw motion tracer facilitated the transfer of personalized occlusal plane positions and recorded jaw motion, which can be integrated into the digital prosthetic workflow for virtual occlusion adjustment. Occlusal design based on patient-specific motion more effectively restored lingual guidance of maxillary anterior crowns.

Fully digital workflow for the fabrication of occlusal stabilization splints based on individual mandibular movement.

OBJECTIVE: This study was conducted to present a completely digital workflow for the fabrication of occlusal stabilization splints using CAD/CAM systems and a digital face bow based on optical sensor technology. METHODS: Digital scans of the maxillary and mandibular arches of 20 volunteers were obtained using an intraoral scanner. Jaw relation and mandibular movements were recorded with a digital face bow via optical sensors. The virtual increase of the vertical dimension of occlusion (VDO) was then performed, after which computer-aided design (CAD) of the occlusal stabilization splints was carried out. The corresponding splints were then manufactured using digitally controlled technology. RESULTS: A completely digital workflow for the manufacturing of occlusal stabilization splints was found to be clinically feasible. The corresponding data analysis revealed high congruence between virtual and physical occlusal contacts on the occlusal splint. Moreover, the appropriate guidance of the anterior teeth area was easily obtainable, and the time for adjusting the occlusion was less. CONCLUSIONS: This study demonstrated that the fabrication of occlusal stabilization splints using a fully digital workflow is feasible. Compared to traditional impression-based manufacturing, several advantages of digital manufacturing include easy accessibility, time-efficient manufacturing, high-level accuracy in splint quality, and potential to manufacture duplicate splints. CLINICAL SIGNIFICANCE: The proposed fully digital approach may help young dentists fabricating stable occlusal splints with beneficial curative effects. Meanwhile, it could also improve the production efficiency of stable occlusal splints, saving time for both doctors and patients while reducing labor costs.

Association between psychological stress, anxiety and oral health status among college students during the Omicron wave: a cross-sectional study.

BACKGROUND: Within 3 years of the COVID-19 pandemic, increasing interest has been given to its potential influence on health status due to lockdowns caused by the pandemic. However, the impact is inadequately understood, especially for college students. This study aimed to investigate the potential association between psychological stress, anxiety and oral health of college students during the Omicron wave of the COVID-19 pandemic. METHODS: An online survey with measurements of psychological stress, anxiety and oral health was completed by 1770 Chinese college students. The Perceived Stress Scale-14 (PSS-14) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure psychological stress and anxiety, respectively. Oral health status was self-reported including toothache, gingival bleeding, and oral ulcer. Multivariable logistic regressions were performed to determine underlying associations for outcome variables. Structural equation modeling (SEM) was performed to confirm the relationship between mental and oral health status. RESULTS: Of the 1770 subjects, 39.2% presented high psychological stress and only 41.2% expressed no anxiety. A significant association was found between psychological stress, anxiety and oral health status. Anxiety has significant impacts on toothache (OR = 0.36; 95%CI: 0.23-0.55; p < 0.01), gingival bleeding (OR = 0.43; 95%CI: 0.29-0.65; p < 0.01), and oral ulcer (OR = 0.54; 95%CI: 0.36-0.80; p < 0.01). Anxiety significantly mediated the association between psychological stress and self-reported oral symptoms. CONCLUSIONS: Anxiety may be a significant risk indicator for mental health among college students and demonstrates a significant relationship with the occurrence of self-reported oral symptoms. Concerns about academic and life changes caused by the pandemic were the two most significant sources of stress.

Influence of wearing mouthguards on performance among athletes: A systematic review.

OBJECTIVES: While the use of mouthguards is well established to prevent orofacial and dental trauma occurrence, limited evidence exists regarding their influence on athletic performance. The objective of this study was to conduct a systematic review of the literature to assess the effect of wearing mouthguards on athletic performance. DESIGN: Systematic review. METHODS: An extensive search was performed in the databases of PubMed/MEDLINE, Embase, Scopus and Cochrane Library for studies published up to August 2022. Only peer-reviewed studies involving humans in vivo and investigating the use of mouthguards on performance among athletes were included. Quality assessment was performed using the Cochrane Collaboration's risk of bias tool. RESULTS: The initial query yielded 4785 citations, of which 41 studies met the inclusion criteria, comprising a total of 852 athletes. Overall, wearing mouthguards was found to improve athletic performance compared to the control group (without mouthguards). Custom-made mouthguards were found to be more effective in enhancing athletic performance compared to other types of mouthguards. CONCLUSIONS: Wearing mouthguards should be advocated by athletes not only for the prevention of orofacial and dental trauma but also for their potential improvements in athletic performance in specific actions. However, caution must be exercised in interpreting these findings due to the variability in outcome measures and the lack of important methodological details.

A fully digital workflow to register maxillomandibular relation using a jaw motion tracer for fixed prosthetic rehabilitation: A technical report.

OBJECTIVE: This technique aimed to describe a fully digital workflow to register maxillomandibular relation for fixed prosthetic rehabilitation. CLINICAL CONSIDERATIONS: Mandibular kinematics could be reproduced in a four-dimensional (4D) virtual patient based on the intraoral scan, facial scan, cone beam computed tomography, and jaw motion trajectory, which helped record centric relation and determine a proper occlusal vertical dimension in a virtual environment. The therapeutic position could be exported directly to the dental computer-aided design software for digital waxing design with a facial scan. The 4D virtual patient was also used to verify the functional and esthetic outcomes of provisional restorations. CONCLUSIONS: This novel approach digitized the process of determination, delivery, and double-check of maxillomandibular relation, thus contributing to the establishment of a completely digital workflow for fixed prosthetic rehabilitation. CLINICAL SIGNIFICANCE: Registration of maxillomandibular relation, including centric relation and occlusal vertical dimension is critical to the success of prosthetic rehabilitation. Traditional procedures are complex and time-consuming, and heavily rely on the clinical experience of dentists. A fully digital approach to creating a 4D virtual patient and registering the maxillomandibular relation is established, which guides to determine a proper occlusal vertical dimension in centric relation. Digital delivery and double-check can simplify the conventional procedure and ensure that the determined maxillomandibular relation is reliable.

Ta4C3-Modulated MOF-Derived 3D Crosslinking Network of VO2(B)@Ta4C3 for High-Performance Aqueous Zinc Ion Batteries.

A two-dimensional MXene (Ta4C3) was innovatively used herein to modulate the space group and electronic properties of vanadium oxides, and the MXene/metal-organic framework (MOF) derivative VO2(B)@Ta4C3 with 3D network cross-linking was prepared, which was then employed as a cathode to improve the performance of aqueous zinc ion batteries (ZIBs). A novel method combining HCl/LiF and hydrothermal treatments was used to etch Ta4AlC3 to obtain a large amount of accordion-like Ta4C3, and the V-MOF was then hydrothermally grown on the surface of the stripped Ta4C3 MXene. During the annealing process of V-MOF@Ta4C3, the addition of Ta4C3 MXene liberates the V-MOF from agglomerative stacking, allowing it to show additional active sites. More significantly, Ta4C3 prevents the V-MOF in the composite structure from converting into V2O5 of space group Pmmn but into VO2(B) of space group C2/m after annealing. A considerable advantage of VO2(B) for Zn2+ intercalation is provided by the negligible structural transformation during the intercalation process and the special tunnel transport channels, which have an enormous area (0.82 nm2 along the b axis). According to first-principles calculations, there is a strong interfacial interaction between VO2(B) and Ta4C3, which deliver remarkable electrochemical activity and kinetic performances for the storage of Zn2+. Therefore, the ZIBs prepared with the VO2(B)@Ta4C3 cathode material exhibit an ultra-high capacity of 437 mA h·g-1 at 0.1 A·g-1 while showing good cycle performance and dynamic performance. This study will offer a fresh approach and a reference for creating metal oxide/MXene composite structures.

Mesoporous TiO2 Coatings Regulate ZnO Nanoparticle Loading and Zn2+ Release on Titanium Dental Implants for Sustained Osteogenic and Antibacterial Activity.

Two major issues are currently hindering the clinical practice of titanium dental implants for the lack of biological activities: immediate/early loading risks and peri-implantitis. To solve these issues, it is urgent to develop multifunctional implants modified with effective osteogenic and antibacterial properties. Zinc oxide nanoparticles (ZnO NPs) possess superior antibacterial activity; however, they can rapidly release Zn2+, causing cytotoxicity. In this study, a potential dental implant modification was creatively developed as ZnO nanoparticle-loaded mesoporous TiO2 coatings (nZnO/MTC-Ti) via the evaporation-induced self-assembly method (EISA) and one-step spin coating. The mesoporous TiO2 coatings (MTCs) regulated the synthesis and loading of ZnO NPs inside the nanosized pores. The synergistic effects of MTC and ZnO NPs on nZnO/MTC-Ti not only controlled the long-term steady-state release of Zn2+ but also optimized the charge distribution on the surface. Therefore, the cytotoxicity of ZnO NPs was resolved without triggering excessive reactive oxygen species (ROS). The increased extracellular Zn2+ further promoted a favorable intracellular zinc ion microenvironment through the modulation of zinc transporters (ZIP1 and ZnT1). Owing to that, the adhesion, proliferation, and osteogenic activity of bone mesenchymal stem cells (BMSCs) were improved. Additionally, nZnO/MTC-Ti inhibited the proliferation of oral pathogens (Pg and Aa) by inducing bacterial ROS production. For in vivo experiments, different implants were implanted into the alveolar fossa of Sprague-Dawley rats immediately after tooth extraction. The nZnO/MTC-Ti implants were found to possess a higher capability for enhancing bone regeneration, antibiosis, and osseointegration in vivo. These findings suggested the outstanding performance of nZnO/MTC-Ti implants in accelerating osseointegration and inhibiting bacterial infection, indicating a huge potential for solving immediate/early loading risks and peri-implantitis of dental implants.

Evaluation of the accuracy of T-scan system and Cerec Omnicam system used in occlusal contact assessment.

Purpose: The objective of the present study was to determine the accuracy of T-scan system and Cerec Omnicam system with respect to the evaluation of occlusal contact by quantitatively comparing the occlusal contact areas and the overlapping ratios of occlusal contact areas obtained from these systems. Material and methods: The occlusal contact of 20 adolescents with normal occlusion was measured with the T-scan system and the Cerec Omnicam system, respectively. The occlusal contact areas in the intercuspal position were then quantified with Adobe Photoshop CS6 Software. The same procedure was repeated for each subject using with 8 µm articulating paper as the control group. The overlapping ratio of T-scan system and Cerec Omnicam system was calculated respectively, which is defined as the ratio of overlapping areas comparing with those obtained from articulating paper. To examine the accuracy of T-scan system and Cerec Omnicam system, the Paired t-test was applied. The reproducibility of T-scan system was evaluated with Wilcoxon matched-pairs signed-ranks test by comparing the occlusal contact areas between two repeated measurements. In all statistical analysis, the level of significance was set to α = 0.05. Results: Results demonstrated measured occlusal contact areas were significantly different between those obtained between T-scan system and Cerec Omnicam system (P < 0.05). The tooth position of two-dimensional virtual dental arch established by T-scan system based on the width of the central incisor was in disagreement with the actual tooth position. The overlapping ratios obtained from Cerec Omnicam system were higher than those obtained from the T-Scan system (P < 0.05). The sensitivity of T-Scan system in anterior teeth area decreased when sensors are used more than once (P < 0.05). Conclusions: In the intercuspal position, the accuracy of Cerec Omnicam system for occlusal contact assessment is higher than that of T-scan system. The T-scan system demonstrates good reproducibility in the premolar region and the molar region, but poor reproducibility in the anterior teeth region. Clinical implications: In the intercuspal position, Cerec Omnicam system is more accurate than T-scan system, which can quantitatively analyze occlusal relationship in terms of number, position, size and distribution of occlusal contact points. When evaluating occlusal contacts, the accuracy of T-scan system in anterior teeth region is significantly lower than that of premolar and molar regions.

Psychological stress: neuroimmune roles in periodontal disease.

Periodontitis is a chronic inflammatory disease that starts with pathogenic bacteria and is mediated by a combination of multiple factors. Psychosomatic factors are considered to be one of the most critical risk factors for periodontal disease. Psychological stress may threaten periodontal immune homeostasis in multiple ways by affecting the hypothalamic-pituitary-adrenal cortex system, the locus ceruleus-sympathetic-adrenal medulla system, and the peptidergic nervous system. In this review, we outline the complex role of psychological stress in promoting the development of periodontal disease, focusing on the effects of stress on flora metabolism, tissue inflammation, and alveolar bone homeostasis. At the same time, we broadly and deeply summarize the potential mechanisms of psychological stress-induced periodontal disease, emphasize the importance of neuroimmune modulation for periodontal health, and expect to provide a new perspective for periodontal science based on psychoneuroimmunology.

Accuracy of three-dimensional optical devices for facial soft-tissue measurement in clinical practice of stomatology: A PRISMA systematic review.

BACKGROUND: The accuracy of 3-dimensional (3D) optical devices for facial soft-tissue measurement is essential to the success of clinical treatment in stomatology. The aim of the present systematic review was to summarize the accuracy of 3D optical devices used for facial soft-tissue assessment in stomatology. METHODS: An extensive systematic literature search was performed in the PubMed/MEDLINE, Embase, Scopus and Cochrane Library databases for studies published in the English language up to May 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Peer-reviewed journal articles evaluating the facial soft-tissue morphology by 3D optical devices were included. The risk of bias was performed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2 guidelines by the 2 reviewers. The potential publication bias was analyzed using the Review Manager software. RESULTS: The query returned 1853 results. A total of 38 studies were included in this review. Articles were categorized based on the principle of devices: laser-based scanning, structured-light scanning, stereophotogrammetry and red, green, blue-depth camera. CONCLUSION: Overall, the 3D optical devices demonstrated excellent accuracy and reliability for facial soft-tissue measurement in stomatology. red, green, blue-depth camera can collect accurate static and dynamic 3D facial scans with low cost and high measurement accuracy. Practical needs and availability of resources should be considered when these devices are used in clinical settings.

Trueness of One Stationary and Two Mobile Systems for Three-Dimensional Facial Scanning.

PURPOSE: To evaluate the trueness of one stationary and two mobile systems for 3D facial scanning. MATERIALS AND METHODS: Twenty participants were included in this study. After marking facial soft tissue landmarks, their faces were scanned using three facial scanning systems: the Bellus3D Dental Pro app on an iPad Pro 2020 (Apple; IP); the ARC-7 Face Scanning System (Bellus3D; BA); and the EinScan Pro 2X Plus (Shining 3D Tech; EP) following the manufacturers' operating instructions. Three-dimensional images were reconstructed with corresponding software and saved in object (OBJ) file format. The interlandmark distances were measured and compared to direct caliper measurements, and absolute error (AE) was chosen as the measurement to determine the trueness of the three scanners. The normal distribution and variance of homogeneity were measured, and then the data were analyzed using one-way ANOVA or Kruskal-Wallis H test. The significance level was set at P = .05. RESULTS: For the measurement of interlandmark distances, no significant differences were found among the four measuring techniques, and the mean AEs of the IP, BA, and EP systems were 1.17 ± 0.80 mm, 0.76 ± 0.61 mm, and 0.69 ± 0.65 mm. CONCLUSION: The three facial scanning systems tested provided a reliable 3D facial reconstruction. The portable IP system could meet the clinical requirements for facial scanning, but it is suggested to select the EP and BA systems when a higher trueness is required.

Predictable digital restorative workflow for minimally invasive esthetic rehabilitation utilizing a virtual patient model with global diagnosis principle.

OBJECTIVE: The conventional anterior esthetic treatment protocol is limited as it's time consuming and unreliable. A predictable digital workflow for minimally invasive anterior esthetic tooth rehabilitation with global diagnosis principle has been introduced in this report. CLINICAL CONSIDERATIONS: A 23-year-old female patient with the chief complaint of unsatisfied shape and color of her anterior teeth visited our hospital for restorative consultation. Three-dimensional Digital Smile Design was used to integrate into a virtual patient model to provide rehabilitative esthetic planning with global diagnostic principle. 3D printer was used for communication and guidance preparation. Digital impression and computer-aided design/computer-aided manufacturing technologies were adopted for making the morphology of designed restorations that can precisely transfer to definitive prostheses. The esthetics, functional occlusion, and gingival tissues remained stable for over a follow-up period of 3 years. No signs of fractures within the restorations were observed. CONCLUSIONS: Minimally invasive anterior esthetic tooth rehabilitation can be readily achieved using a predictable digital workflow with global diagnosis principle. CLINICAL SIGNIFICANCE: This digital approach might promote diagnosis, enhance communication, reduce processing time, and increase the predictability of final outcomes with high comfort and esthetic effect.

Oxygen-Terminated Nb2CO2 MXene with Interfacial Self-Assembled COF as a Bifunctional Catalyst for Durable Zinc-Air Batteries.

The desirable air cathode in Zn-air batteries (ZABs) that can effectively balance oxygen evolution and oxygen reduction reactions not only needs to adjust the electronic structure of the catalyst but also needs a unique physical structure to cope with the complex gas-liquid environment. In this work, first-principles calculations were carried out to prove that oxygen-terminated Nb2CO2 MXene played an active role in enhancing the sluggish reaction of oxygen intermediates. Nb2CO2 MXene could also stimulate the spatial accumulation of discharge products, which was beneficial to improve the stability of secondary ZABs. Molecular dynamics simulation was used to show that the confinement effect of COF could effectively regulate the concentration of O2 on the surface of Nb2CO2@COF, which was conducive to an efficient and durable reaction. COF-LZU1 was self-assembled on the interface of Nb2CO2 MXene (Nb2CO2@COF) for the first time. The Nb2CO2@COF electrode had excellent OER/ORR overpotentials with the potential difference (ΔE) of 0.79 V. When applied to the configuration of ZABs, Nb2CO2@COF showed a power density of 75 mW cm-2 and favorable long-term charge/discharge stability, so it could be used as a potential candidate cathode for noble-metal-based catalysts. This idea of combining MXenes and COFs sheds some light on the design of ZABs.

Changes of neuroplasticity in cortical motor control of human masseter muscle related to orthodontic treatment.

BACKGROUND: Orthodontic treatment is a common clinical method of malocclusion. Studies have found that neurons in the sensorimotor cortex of the brain undergo adaptive remodeling in response to changes in oral behavior or occlusion. OBJECTIVE: To explore whether orthodontic treatment could be sufficient to cause neuroplastic changes in the corticomotor excitability of the masseter muscle. METHODS: Fifteen Angle Class II malocclusion patients who were receiving orthodontic treatment participated in the study. Cortical excitability was assessed by electromyographic activity changes evoked by transcranial magnetic stimulation. Four orthodontic time points were recorded, including baseline, day 1, day 7, and day 30. Motor evoked potentials (MEPs) were recorded in the masseter muscle and the first dorsal interosseous muscle (FDI) serving as a control. The data were analysed by stimulus-response curves and corticomotor mapping. Statistical analyses involved repeated measures analysis of variance, two-way ANOVA, and Tukey's post hoc tests. RESULTS: Motor evoked potentials (MEPs) of the masseter muscle were significantly decreased during orthodontic treatment compared with those of the baseline (p < .001). MEPs of the masseter muscle were dependent on session and stimulus intensity (p < .001), whereas MEPs of FDI were only dependent on stimulus intensity (p = .091). Finally, Tukey's post hoc tests demonstrated that MEPs of the masseter muscle on days 1 and 7, with 70%-90% stimulus intensities, were higher than those of baseline values (p < .001). CONCLUSIONS: The present study suggested that orthodontic treatment can lead to neuroplastic changes in the corticomotor control of the masseter muscle, which may add to our understanding of the adaptive response of subjects to changes of oral environment during the orthodontic treatment.

Application of visualization technology of multimode data fusion in occlusal rehabilitation.

OBJECTIVES: This study aimed to present a method for multi-modal medical data fusion that could be used for increased vertical dimension of occlusion (VDO) and occlusal rehabilitation in a digital manner, thus facilitating the process of clinical diagnosis and restoration. METHODS: With the aid of a computer software, a visual and operable four-dimensional virtual dental patient was created by data fusion of intraoral scan, extra-oral face scan, cone-beam computed tomography, and dynamic occlusal movement trace to conduct a systematical review of the occlusion and temporomandibular joint of the virtual patient. This approach could be used for increased VDO on the basis of the aesthetics of anterior teeth and the restoration space of posterior teeth. It allowed jaw reconstruction and occlusal rehabilitation with fixed prosthesis by using computer-aided design and manufacturing (CAD/CAM) devices. RESULTS: A visual and operable four-dimensional virtual dental patient was created by integrating the method for multimodal medical data fusion with CAD/CAM devices, thus making the process of occlusal rehabilitation with fixed prosthesis safer and more convenient than before. CONCLUSIONS: With the method for multimodal medical data fusion, the presented application enables the fusion of different data sources of the patient at the same time and space by creating a virtual patient. It is useful for showing the function and anatomical structure of the patient's oral and maxillofacial system in a visual and convenient manner, thus providing a powerful tool in the process of clinical diagnosis and restoration.

Consensus on the preparation margin and restoration margin in ceramic esthetic rehabilitation.

In esthetic rehabilitation, methods used to enhance the margin quality have always been the focus and difficulty of improving the level of diagnosis and treatment, prevention and treatment of complications, and collaboration between clinicians and technicians. However, it is impeded by the ambiguous definition and classification of margin, unstandardized tooth preparation, manufacturing process of restoration, and lack of reliable means of checking the quantitative requirements of preparation or restoration. The digital technologies that are increasingly applied, such as intra-oral scanner, impression scanner, and computerized numerical control cutting machine, have strict requirements about margin quality. Failure of recognizing margins by these scanners will hinder the digital process of diagnosis and treatment. Even if these sharp and narrow margins are successfully scanned, they cannot be milled accurately. To overcome these problems, this article demonstrated the clear and complete definition of preparation margin and restoration margin, as well as their subclassifications, by analyzing the target restoration space from a geometric perspective. Practical approaches to measuring the margin width and inspecting the margin quality were proposed. The new and full understanding and proposal about preparation margin and restoration margin characterized by measurements will effectively support the thoroughly digitalized process of esthetic rehabilitation using porcelain in fixed prosthodontics, which is based on the guidance of values.

The creation of a virtual dental patient with dynamic occlusion and its application in esthetic dentistry.

The application of a virtual dental patient with dynamic occlusion during esthetic restoration in a digital workflow is described. An intraoral scanner, a facial scanner, a jaw motion analyzer, and cone beam computed tomography were used to transfer patient data and construct the virtual dental patient. With the aid of the virtual dental patient, predictability and accuracy can increase throughout treatment, simplifying the clinical evaluation and prosthesis adjustment with improved esthetic outcomes.

Ring-Patterned Perovskite Single Crystals Fabricated by the Combination of Rigid and Flexible Templates.

Regular microstructures can improve the electrical and optical characteristics of perovskite single crystals because of the removal of defects and grain boundaries. Microstructured single crystals are commonly fabricated by either rigid or flexible templates. However, rigid templates usually need surface treatment before crystal fabrication to create an antiadhesion layer, while flexible templates encounter difficulties in achieving a large area of uniform single crystals without any deformation. In this work, we present a facile and robust method to fabricate perovskite single crystals using rigid silicon pillars coated with flexible polymer solutions, in which surface treatment is avoided in the preparation process, and deformation is absent in the formed crystals. The method realized the fabrication of colorful concentric-ring patterns composed of nanoscale single crystals for the first time. In order to concisely control the preparation of the template, the Newton's ring phenomenon was used to value the droplet height because the number of rings changed with the optical path difference. A related digital simulation was performed to find the correlation of the Newton's ring pattern with the shape of the droplets. The simulated results were consistent with the experimental observations generally, indicating that the pattern could be controlled mechanically. Concomitantly, the resulting perovskite nanoscale single crystals formed a regular colorful concentric-ring pattern. By changing the design of the rigid templates, the parameters of the fabrication process, or the selection of the coating polymer solution, different ring-patterned single crystals were successfully prepared without surface treatment and deformation. The crystals have potential applications in lasers or photodetectors.

[Influence of canine vertical position on smile esthetic perceptions by using 3D digital facial reconstruction].

PURPOSE: To verify the impact of alterations in the vertical position of maxillary canine on smile esthetic perceptions, in order to find an optimal canine position. METHODS: A volunteer's dentition and facial images were scanned by intra-oral scanning and three-dimensional facial scanning, which were then calibrated. In virtue of dental computer-aided design software, the canine vertical positions were symmetrically modified in a variable of 0.5 mm, creating 4 new 3D virtual digital smile faces varying from 1.0 mm of intrusion to 1.0 mm of extrusion. A total of 5 3D virtual digital smile faces were evaluated from the front and 45°to the right sides by 60 dentists and 60 laypersons on a visual analog scale. The data were input into SPSS 20.0 software package, ANOVA of repeated measurement was used to compare the differences in the assessment scores between two groups and rank sum test was used to analyze the differences from different evaluation angles. RESULTS: Alterations in the vertical position of maxillary canine had significant influence on the esthetic evaluation of the smile(P<0.05); there was significant difference between the dentists' and laypersons' esthetic evaluations after the canine vertical position being modified(P<0.05), there was no significant difference on the evaluations of smile esthetics from different evaluation perspectives(P>0.05). CONCLUSIONS: The most attractive smile was the one with canine cusp 0.5 mm vertically higher than the incisal edge of the lateral incisor. The smile is not attractive when the cusp of canine is vertically lower than the incisal edge of lateral incisor. These results can be used as references in the esthetic treatment planning for anterior maxillary teeth.