Search Results (52)

Background: Acrylic resin-based materials are a versatile category used extensively in various dental applications. Processed by current modern technologies, such as CAD/CAM technologies or 3D printing, these materials have revolutionized the field of dentistry for the efficient creation of dental devices. However, despite their extensive use, a limited number of comparative studies exist that investigate how different processing methods—such as traditional techniques, 3D printing, and CAD/CAM milling—impact the nano-mechanical behavior and internal porosity of these materials, which are critical for their long-term clinical performance. Objectives: The purpose of this study is to evaluate the nanomechanical properties (hardness, elasticity, and stiffness) and micro-porosity of acrylic resin-based materials indicated for temporary prosthodontic appliances manufactured by new technologies (milling, 3D printing) compared to traditional methods. Methods: The hardness, elasticity, and stiffness measurements were performed by the nano-metric indentation method (nanoindentation), and the quantitative morphological characterization of the porosity of the acrylic resin samples obtained by 3D printing and CAD/CAM milling was performed by micro-computed tomography. Results: According to nanomechanical investigations, CAD/CAM milling restorative specimens exhibited the greatest mechanical performances (E~5.233 GPa and H~0.315 GPa), followed by 3D printed samples, while the lowest mechanical properties were registered for the specimen fabricated by the traditional method (E~3.552 GPa, H~0.142 GPa). At the same time, the results of porosity studies (micro-CT) suggested that 3D printed specimens demonstrated a superior degree of porosity (temporary crown—22.93% and splints—8.94%) compared to CAD/CAM milling restorative samples (5.73%). Conclusions: The comparative analysis of these results allows for the optimal selection of the processing method in order to ensure the specific requirements of the various clinical applications. Full article

Background/Objectives: MARPE expansion is known to produce maxillary skeletal expansion and cause subsequent increase in velopharyngeal, oropharyngeal, and nasal volume. While MARPE designs vary and may include combinations of traditional bands, traditional jackscrews, or milled/3D printed frameworks with other screw designs, there is no agreement on the techniques of MARPE expansion in adult patients. The aim of this case series is to describe a novel 3D-printed and 3D-designed midpalatal piezocorticotomy guide and its benefits for MARPE-assisted midfacial skeletal expansion. Materials and Methods: This case series showcases the results of successful MARPE expansion in adults and introduces the novel 3D-printed midpalatal piezocorticotomy guide. It compares the outcome of non-guided piezocorticotomy-assisted maxillary skeletal expansion and outlines the benefits of pre-planned 3D-guided midpalatal piezocorticotomy. Results: The MARPE expansion outcomes when combined with 3D-designed and 3D-printed midpalatal piezocorticotomy guides are shown to be predictable and capable of preventing asymmetric expansion along with asymmetric suture opening. The technique, in particular, allows for one to preserve the position of the nasal septum and prevents asymmetrical nasal septum dislodgement following maxillary skeletal expansion. Conclusions: The described novel midpalatal piezocorticotomy guide presents a significant improvement to adult midfacial techniques using MARPE expansion appliances. Full article

The objective of the present study was to evaluate and compare the accuracy of the computer-aided static navigation technique (NAV), augmented reality (AR) and freehand placement technique (FHT) for the bicortical orthodontic self-drilling mini-implants for maxillary skeletal expansion (MSE) appliances placed in palate. Material and Methods: A total of 120 bicortical orthodontic self-drilling mini-implants were placed in the palate of ten 3D printed anatomically based polyurethane models of a completely edentulous upper maxilla. The orthodontic mini-implants were randomly assigned to the following placement techniques: (A) computer-aided static navigation technique (n = 40) (NAV), (B) augmented reality device (n = 40) (AR) and (C) conventional freehand technique (n = 40) (FHT). Moreover, two implants were placed in each side of the midpalatal suture in every model according to the digital planification of the expander device. Subsequently, the orthodontic mini-implants were placed and postoperative CBCT scans were performed. Finally, coronal entry-point (mm), apical end-point (mm) and angular deviations (°) were calculated using a t-test. Results: Statistically significant differences were shown at coronal entry-point (p < 0.001), apical end-point (p < 0.001) and angular deviations (p < 0.001) between the three placement techniques of bicortical orthodontic mini-implants. Additionally, statistically significant differences were also shown between the orthodontic mini-implant positions concerning the entry point (p = 0.004) and angular deviation (p = 0.004). Conclusions: The augmented reality placement technique results are more accurate, followed by the computer-aided static navigation technique and the freehand technique for MSE appliances placed in palate. Full article

Objectives: This study investigated the use of artificial intelligence (AI) in the design of lingual bracket indirect bonding trays and its association with bracket transfer accuracy using three-dimensional (3D) printing. Methods: Digital impressions of patient’s dental arches were captured using an intraoral scanner, and orthodontic setups were virtually constructed. Brackets were virtually positioned in their ideal locations using the digital setups guided by virtual archwire templates. Indirect bonding trays were automatically generated using the AI-powered Auto Creation function of the Medit Splints application, which analyzes anatomical features to streamline design. Bracket transfer accuracy was evaluated in vivo by comparing planned and actual bracket positions across grouped and individual tray configurations. Linear and angular deviations were measured using conventional 3D inspection software. Results: Most bracket transfer errors were within clinically acceptable thresholds, although torque accuracy remained suboptimal. Grouped trays generally exhibited greater precision than individual trays in several dimensions. Conclusions: These findings support the application of AI-assisted design tools to enhance digital workflows and improve consistency in appliance fabrication. Full article

Background: Canines play a vital functional and aesthetic role in human dentition, yet impacted canines, particularly in the mandible, are rare and can lead to functional disorders, such as the absence of canine guidance, while negatively affecting a patient’s self-esteem. Transmigration of mandibular canines adds complexity to treatment. One method to reduce the treatment time, especially for impacted teeth, is corticotomy-assisted orthodontic therapy (CAOT). Methods: A 13-year-old patient presented with a horizontally impacted lower right canine, positioned below the roots of the lower incisors, showing transmigration. A digitally designed and 3D-printed lingual appliance was attached to the lower molars with hooks on the lingual side, enabling the application of multi-directional orthodontic forces. CAOT was performed using an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) at 200 mJ, 12 Hz, 2.4 W, with a pulse duration of 100 µs, and an MSP H14 conical tip (0.6 mm spot diameter). Photobiomodulation (PBM) with a 635 nm diode laser (Lasotronix, Smart ProM, Piaseczno, Poland) was applied at 10 J per point (20 J/cm²) for 100 s per point, with a total energy of 20 J per session to reduce the risk of root resorption, manage pain, and accelerate healing as the tooth was moved into the alveolar ridge. Results: The treatment duration was two and a half years. The lingual appliance with hooks allowed precise traction of the canine, aided by exposure from the lingual side and the attachment of a hook. Gentle forces applied via orthodontic thread gradually moved the canine beneath the oral mucosa. Mid-treatment cone beam computed tomography (CBCT) scans confirmed the absence of root resorption of the lower incisors. A corticotomy, enhanced by laser therapy, was performed before moving the canine into the alveolar ridge. The canine was successfully rotated 180° and positioned without any signs of resorption in the canine or adjacent teeth. Conclusions: The use of a digitally designed and 3D-printed lingual appliance with hooks allowed the precise control of the traction of impacted teeth. When combined with corticotomy and laser therapy, it minimised root resorption risks, reduced pain, accelerated healing, and improved the overall success of the orthodontic treatment. Full article

Additive manufacturing (3D printing) has transformed dentistry by providing solutions with high precision and accuracy achieved through digital workflows, which facilitate the creation of intricate and personalized structures. Additionally, 3D printing promotes cost efficiency by reducing material waste and errors while enabling on-demand production, minimizing the need for extensive inventories. Recent advancements in 3D-printed resin materials have enhanced their clinical applications by improving mechanical strength, biocompatibility, esthetics, and durability. These innovations have facilitated the fabrication of complex and patient-specific structures, such as dental prostheses, surgical guides, and orthodontic appliances, while significantly reducing production time and material waste. Ongoing research and innovation are expected to strengthen resin properties, including strength, translucency, and durability, broadening their clinical applications. The ongoing evolution of 3D printing technology is poised to play a critical role in driving personalized treatments, streamlining clinical workflows, and shaping the future of dental care. This narrative review comprehensively examines the production techniques and clinical applications of 3D-printed photopolymer resins across various dental specialties, including prosthodontics, orthodontics, pediatric dentistry, maxillofacial surgery, periodontology, endodontics, and conservative dentistry. Additionally, the review provides insight into the transformative impact of these technologies on patient care, highlights existing challenges, and suggests future directions for advancing resin properties and their integration into routine dental practice. Full article

Background/Objectives: Bruxism is a masticatory muscle activity, phasic or tonic, with/without teeth contact, that appears in sleep or an awake state. An instrumental technique used to measure the surface electromyographic (sEMG) activity of the masseter muscle is used to diagnose bruxism activity during sleep and while awake. The objective of this study was to compare the variation in bruxism (sleep and awake) indices and masseter activity indices in low sleep bruxism and moderate sleep bruxism before and after wearing an occlusal appliance (OA) for 3 months each night. Methods: A clinical interventional study was designed in which subjects diagnosed with sleep bruxism were randomly selected to be included in the study. After the first sEMG recording, two groups were formed: a low sleep-bruxism group (number of sleep-bruxism events/h between 2 and 4) and a moderate sleep-bruxism group (number of sleep-bruxism events/h equal or higher than 4). All subjects received treatment with a 3D-printed occlusal appliance and wore it each night for 3 months, at which point the second sEMG recording was performed. For each participant of this study, a chart was created that included anamnestic data, clinical data, and sEMG data. The data were statistically analyzed with SPSS, using the Mann–Whitney U and Wilcoxon signed-rank tests. Results: A total of 21 participants were included in the final analysis, 18 women and 3 men, with a mean age of 24.5 ± 2.7 years. The OA lowered all bruxism indices in the whole group, but clusters analysis showed a significant reduction in sleep-bruxism indices in the moderate sleep-bruxism group, while in the low-bruxism group, the sleep and awake indices varied insignificantly, and the number of sleep-bruxism events/h remained constant. Conclusions: The 3D-printed occlusal appliances significantly lowered the sleep-bruxism indices and sleep masseter activity indices recorded with a portable sEMG device in the moderate sleep-bruxism group. The OA lowered the awake-bruxism indices and awake masseter activity indices in the moderate sleep-bruxism group. Full article

This scoping review aims to provide a comprehensive summary of the current literature on 3D-printed orthodontic aligners. It was conducted following the Preferred Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. An electronic literature search was conducted across the PubMed, Embase, and Web of Science databases. After applying the inclusion criteria, a total of 46 eligible studies published until September 2024 were selected for qualitative synthesis. To date, scientific evidence is primarily available for Tera Harz TC (Graphy, Seoul, Republic of Korea), which is the only studied material approved for orthodontic tooth movements. Although additional materials were identified during the literature search, there is a lack of scientific studies regarding their characteristics and clinical use. This review highlights that while material properties and biocompatibility are of critical importance, the clinical efficacy and long-term safety of 3D-printed aligners require further investigation. Many studies exhibit significant variability in testing methodologies, making substantiated comparisons challenging. Moreover, the existing literature primarily comprises in vitro studies, with limited clinical trials assessing the effectiveness of 3D-printed aligners. Given the current gaps in knowledge and the evolving nature of this field, further well-designed controlled clinical studies are necessary to evaluate the clinical performance and safety of 3D-printed aligners. The findings underscore the need for standardized protocols and comprehensive reporting to enhance the reliability of future research in this area. Full article

Surface engineering is one of the most extensive industries. Virtually all areas of the economy benefit from the achievements of surface engineering. Surface quality affects the quality of finished products as well as the quality of manufactured parts. It affects both functional qualities and esthetics. Surface quality affects the image and reputation of a brand. This is particularly true for cars and household appliances. Surface modification of products is also aimed at improving their functional and protective properties. This applies to surfaces for producing hydrophobic surfaces, anti-wear protection of friction pairs, corrosion protection, and others. Metal technologies and 3D printing benefit from surface technologies that improve their functionality and facilitate the operation of products. Surface engineering offers a range of different coating and layering methods from varnishing and painting to sophisticated nanometric coatings. This paper presents an overview of selected surface engineering issues pertaining to metal products, with a particular focus on surface modification of products manufactured by 3D printing technology. It evaluates the impact of the surface quality of products on their functional and performance qualities. Full article

In recent years, additive manufacturing (AM) has been recognized as a transformative force in the dental industry, with the ability to address escalating demand, expedite production timelines, and reduce labor-intensive processes. Despite the proliferation of three-dimensional printing technologies in dentistry, the absence of well-established post-processing protocols has posed formidable challenges. This comprehensive review paper underscores the critical importance of precision in post-processing techniques for ensuring the acquisition of vital properties, encompassing mechanical strength, biocompatibility, dimensional accuracy, durability, stability, and aesthetic refinement in 3D-printed dental devices. Given that digital light processing (DLP) is the predominant 3D printing technology in dentistry, the main post-processing techniques and effects discussed in this review primarily apply to DLP printing. The four sequential stages of post-processing support removal, washing, secondary polymerization, and surface treatments are systematically navigated, with each phase requiring meticulous evaluation and parameter determination to attain optimal outcomes. From the careful selection of support removal tools to the consideration of solvent choice, washing methodology, and post-curing parameters, this review provides a comprehensive guide for practitioners and researchers. Additionally, the customization of post-processing approaches to suit the distinct characteristics of different resin materials is highlighted. A comprehensive understanding of post-processing techniques is offered, setting the stage for informed decision-making and guiding future research endeavors in the realm of dental additive manufacturing. Full article

Three-dimensional printing technology continues to evolve, enabling new applications in manufacturing. Extensive research in the field of biomimetics underscores the significant impact of the internal geometry of building envelopes on their thermal performance. Although 3D printing holds great promise for improving thermal efficiency in construction, its full potential has yet to be realized, and the thermal performance of printed building components remains unexplored. The aim of this paper is to experimentally examine the thermal insulation characteristics of prototype cellular materials created using 3D additive manufacturing technologies (SLS and DLP). This study concentrates on exploring advanced thermal insulation solutions that could enhance the energy efficiency of buildings, cooling systems, appliances, or equipment. To this end, virtual models of sandwich composites with an open-cell foam core modeled after a Kelvin cell were created. They were characterized by a constant porosity of 0.95 and a pore diameter of the inner core of the composites of 6 mm. The independent variables included the different material from which the composites were made, the non-uniform number of layers in the composite (one, two, three, and five layers) and the total thickness of the composite (20, 40, 60, 80, and 100 mm). The impact of three independent parameters defining the prototype composite on its thermal insulation properties was assessed, including the heat flux (q) and the heat transfer coefficient (U). According to the experimental tests, a five-layer composite with a thickness of 100 mm made of soybean oil-based resin obtained the lowest coefficient with a value of U = 0.147 W/m²·K. Full article

Additive manufacturing resins used in dental prosthetics may retain uncured monomers post-polymerization, posing potential long-term patient exposure risks. Understanding the biological safety of these materials is crucial, particularly for 3D-printed acrylic-based prosthodontic devices such as occlusal nightguards, complete and partial dentures, and temporary fixed prostheses. This paper reviews the literature evaluating the cytotoxicity of such materials. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, we conducted a scoping review using the MESH keywords related to population (P), intervention (I), comparison (C), and outcome (O) across databases, including OVID Medline, EMBASE, and SCOPUS. Our search, limited to peer-reviewed English language articles from 2015 to 2023, resulted in 22 papers. These studies, utilizing digital light processing (DLP) or stereolithography (SLA) printing methods, varied in examining different 3D-printed materials, as well as washing and post-curing protocols. The primary experimental cells used were human gingival fibroblasts (HGF) and mouse fibroblasts (L929). There are no statistical differences in biocompatibility regarding different commercially available resins, washing solutions, or methods. Improvements in cell viability were related to an increase in washing time, as well as post-curing time. After the polishing procedure, 3D resin-based printed occlusal devices perform similarly to milled and conventionally processed ones. Our findings underline the importance of appropriate washing and post-curing protocols in minimizing the cytotoxic risks associated with these 3D-printed resin-based devices. Full article

Background: The need to perform occasional or continuous MRI exams and the interference with metal orthodontic appliances might be important and take a primary role during retention since the retention period is significantly longer than orthodontic treatment. Several non-metallic materials were proposed as potential alternatives to perform fixed retainers in orthodontics, but they showed internal limits. Methods: Polyetheretherketone (PEEK) was used in the present clinical report as a fixed orthodontic retainer in the lower arch in order to perform an appliance with mechanical properties comparable to metallic ones but with a higher biocompatibility material and without the need for removal in case of an MRI exam. The retainer wire was handmade in the studio and then shaped to fit the arch. Results: PEEK showed a good capability for constructing a lingual fixed retainer compared to other aesthetic non-metallic and metallic materials. Conclusions: To the best of our knowledge, this study proposes how to easily build a retainer in PEEK and provides a clinical example of how this material can be beneficial. Full article

Obstructive sleep apnea (OSA) is a prevalent source of sleep-disordered breathing. OSA is most commonly associated with dysfunctions in the genioglossus (GG) muscle. In this study, we present the first version of a medical device that produces an electromyogram (EMG) of the GG. The prototype is composed of a (custom-made) 3D-printed mouthpiece. Impressions were taken for the lower arch and scanned with a lab scanner to be converted into digital impressions. ExoCad software was used to design the appliance. Fusion 360 software was then used to modify the design and create tubes to house the electrodes in a bilateral configuration to secure excellent and continuous contact with the GG muscle. Silver–silver chloride electrodes were incorporated within the appliance through the created tubes to produce a muscle EMG. In this preliminary prototype, an EMG amplifier was placed outside the mouth, and isolated electric wires were connected to the amplifier input. To test the design, we ran experiments to acquire EMG signals from a group of OSA patients and a control group in wakefulness. The GG EMGs were acquired from the participants for 60 s in a resting state whereby they rested their tongues without performing any movement. Then, the subjects pushed their tongues against the fontal teeth with steady force while keeping the mouth closed (active state). Several features were extracted from the acquired EMGs, and statistical tests were applied to evaluate the significant differences in these features between the two groups. The results showed that the mean power and standard deviation were higher in the control group than in the OSA group (p < 0.01). Regarding the wavelength during the active state, the control group had a significantly longer wavelength than the OSA group (p < 0.01). Meanwhile, the mean frequency was higher in the OSA group (p < 0.01) at rest. These findings support research that showed that impairment in GG activity continues in the daytime and does not only occur during sleep. Future research should focus on developing the device to be more user-friendly and easily used at home during wakefulness and sleep. Full article

Objective: To evaluate the differences in frictional resistance between in-house 3D-printed resin brackets (IH3DBs) and two types of commercially available brackets in combination with three different archwires. Methods: Friction tests were performed using a dynamometer and a millimetre sled to simulate first premolar post-extraction space closure. Three different brackets, namely PRIMO metallic brackets, Crystal composite brackets and in-house 3D-printed brackets, were tested in combination with three different archwires (0.016-inch NiTi, 0.019 × 0.025-inch NiTi and 0.019 × 0.025-inch SS). Statistical analysis was performed to verify the differences in friction among the bracket and archwire combinations. For all the tests, the significance level was set at p < 0.05. Results: There were significant differences among the three brackets tested with both the 0.016-inch NiTi and 0.019 × 0.025-inch SS archwires (p = 0.026 and p = 0.017, respectively). Only tests with the 0.019 × 0.025-inch NiTi archwire yielded no statistically significant differences between the groups. The composite bracket generated clinically and statistically more friction than both the IH3DB and metallic bracket, with no differences between the latter two. Conclusions: The IH3DBs demonstrated comparable frictional resistance properties to the metal brackets and better than the composite brackets with all the archwires tested. Full article