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Abstract Background There is a lack of studies comparing the dimensional accuracy and color stability of denture base resins made using computer-aided design and computer-aided manufacturing (CAD-CAM) milling, 3-dimensional (3D) printing, and conventional denture processing techniques. This makes it challenging to determine the best method to fabricate complete dentures. The objective of this in vitro investigation was to assess and contrast the color stability and dimensional accuracy of denture base resins that were 3D printed and CAD-CAM milled, both before and after aging by thermocycling using digital surface matching technology and a benchtop laser scanner without using a spray, to optimize adaptation of the denture base and cast to minimize any imperfections and to evaluate the impact of the denture cleansing solution on the stability of color. Methods Evaluation of the dimensional accuracy (n = 27) was completed on a sectional maxillary stone cast using a digital 3D-surface matching software before and after 5000 thermocycles. A spectrophotometer was used to measure the color change (△E00) of all disc specimens (N = 54) before and after 500 thermocycles and immersion in denture cleansing solution for 30 cycles (3 min each) daily for 6 days. The Kruskal Wallis test, Dunn’s post hoc test, Tukey’s test with Bonferroni adjustment, one sample t test and independent t test were used to statistically analyze the data (α .05), while it had no significant difference on the CAD-CAM milled group at all locations (P .001). Conclusions CAD-CAM milled resins had the highest dimensional accuracy and the best color stability, conventional heat polymerized acrylic resins showed moderate change in dimensional accuracy and color stability, while the 3D- printed resin had the lowest dimensional accuracy and color stability after aging by thermocycling.

Traditional removable partial dentures (RPDs) with cobalt-chromium frameworks have been used for several decades, restoring the masticatory function. However, these frameworks have been documented as aesthetically unacceptable due to the display of metal clasps. The patients' increased demands regarding the aesthetic aspects of rehabilitation treatment led to the introduction of new, more aesthetic materials in clinical practice. One of the main materials is polyetheretherketone (PEEK). This clinical report presents PEEK as an alternative material for fabricating RPD frameworks for a Class III Kennedy partial edentulous mandible. The framework was constructed using CAD/CAM manufacturing, and the process combined laboratory scanning, digital framework design, resin try-in milling, and PEEK framework milling. The framework showed good adaptation to the abutment teeth and surrounding tissues. The patient was followed for 2 years without complaints and was grateful for the aesthetics. During this period, there were no signs of degradation in the framework, and the clasps were still as retentive as they were at the initial appointment, with only some pigmentation of the structure being observed.

Background: Designing the occlusal surface of a prosthesis to ensure optimal eccentric occlusion is challenging without precisely replicating the patient's mandibular movements. During the CAD-CAM prosthesis delivery process, clinicians often need to make adjustments to the prosthesis to avoid occlusal interferences that may occur during lateral excursions. Recently, there have been developments in the field of mandibular motion tracking using optical devices. These approaches seek to incorporate an individual's functional movement into the research field of occlusal morphology. Aim: This study aimed to assess the accuracy of digitally replicating mandibular movements to identify and correct occlusal interferences in monolithic CAD-CAM zirconia crowns. Methods: An intraoral scanner (IOS) was used to capture complete arch maxillary and mandibular teeth and record buccal and lateral interocclusal records of maxillary first premolar abutment teeth of thirteen participants. For each patient, two monolithic zirconia crowns were fabricated following the standard digital workflow. The crowns were categorized based on the virtual method used for adjusting occlusal interferences into two groups: Group I, where occlusal interferences in CAD-CAM zirconia crowns were adjusted using buccal interocclusal records, and Group II, where adjustments were made using both buccal and lateral interocclusal records. After crown fabrication following the manufacturer's instructions, occlusion was analyzed using an electronic pressure analyzer. The mean, standard deviation and median values of the recorded data were measured. Paired t test and Wilcoxon Sign Rank test were executed for analyzing differences between groups (p value ≤ 0.05). Results: Group I recorded higher maximum pressure at lateral mandibular movement with mean ± standard deviation value of 26.00 ± 4.95% than Group II with 20.62 ± 3.38%. Regarding pressure recorded at maximum intercuspation (MI) Group I showed higher results; 8.08 ± 1.50% compared to Group II with 7.23 ± 1.59% mean ± standard deviation value. The average value of crown volume for Group I was (160.36 ± 15.94) mm3, while for Group II was (157.63 ± 14.45) mm3. Conclusions: The digital functionally generated path technique allows for identifying occlusal interferences and modifying CAD-CAM zirconia crown designs. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Overview Conclusion Clinical Significance This review aims to evaluate the current understanding and clinical applications of machinable ceramic‐reinforced composites (CRCs) and the emerging first generation of 3D‐printed CRCs in dental restorations.Machinable CRCs, introduced over a decade ago, have shown moderate success in short‐ to medium‐term clinical applications, particularly in low‐stress areas. However, their long‐term durability limitations, such as increased wear and marginal deterioration, restrict their use in high‐stress situations and full crowns. The first generation of 3D‐printed CRCs offers customization advantages but is still in early development and exhibits lower mechanical strength and higher wear rates than CAD‐CAM CRCs and traditional ceramics. Additionally, the classification and definitions surrounding CRCs remain ambiguous, as ADA categorizations do not clearly differentiate CRCs from ceramics, complicating clinical indication, usage, and billing practices.Machinable CAD‐CAM CRCs are moderately successful in low‐stress applications, while 3D‐printed CRCs show limitations in wear resistance and durability, raising concerns for their use in definitive restorations. Both require further research and clinical validation.Machinable CAD‐CAM CRCs are best suited for low‐stress applications, while 3D‐printed CRCs may be more appropriate for provisional use. Until long‐term clinical data are available, ceramics should be preferred for high‐stress or full‐coverage restorations. Clearer definitions for porcelain/ceramic and comprehensive application guidelines are urgently needed to support clinician decision‐making and improve patient outcomes. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to determine the status of the scientific literature on CAD-CAM resin blocks by mapping the available evidence and identifying knowledge gaps. Data/Source: A systematic search of studies investigating CAD-CAM resin blocks was conducted. Risk of bias was assessed, and data on study designs, level of evidence, compositional classification, manufacturer, commercial brand, and properties investigated were extracted. This review followed Arksey and O'Malley's five-stage framework and utilized Medline (OVID), EMBASE, and Scopus (Elsevier) databases. Study Selection: Study selection resulted in 27 studies for data extraction out of 209 studies screened from an initial pool of 529 studies. High sampling bias related to sample size and randomization was observed in almost all studies. Most studies (99%) were conducted in vitro, with low levels of evidence. The most common composition was "nano-ceramic". 3M ESPE was the manufacturer with the most investigated blocks, and their product, 3M™ Lava™ Ultimate Restorative, was predominant in the selected investigations. Methodological heterogeneity was extensive among the studies, with mechanical properties (38%) and bond strength (35%) being the most commonly investigated outcomes. Conclusion: This scoping review indicates an increasing trend in dental research assessing CAD-CAM resin blocks. However, the overall level of evidence derived from these studies is low, predominantly consisting of in vitro investigations. Clinical Significance: The findings underscore the need for clinical trials to augment the level of evidence and enable long-term assessment of CAD-CAM resin blocks. Dentists should be cautious while interpreting the findings from in vitro studies, as the outcomes may not directly translate to clinical success. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

AbstractOptimal dental health significantly contributes to an individual’s physical and psychological well-being, with an increasing focus on esthetics and functionality in dental restoration procedures. This research explores the use of zirconia ceramic materials combined with calcium silicate and silver compositions as an alternative for dental crown applications. The study employs 3D finite element analysis to assess stress distribution on full crowns with composites under axial and oblique loads, aiming to understand biomechanical aspects and identify fracture resistance and failure modes. The materials include zirconia-calcium silicate-silver composites with varying volume fractions (Zr 74 to 29%, Ca2SiO4 68 to 25%, and Ag 3 to1%). Results show stress concentration at the crown intaglio surface, influenced by the material’s elastic modulus. Specifically, the C14 composite crown with Young’s modulus 90.82 GPa exhibits lower stress levels for crown 10.9 MPa at axial load and 12.77 MPa at oblique load, making it a potentially recommended choice. These findings suggest the potential of designed biomaterials, emphasizing the importance of material selection in enhancing the longevity and resilience of dental crowns. Also, the study enhances understanding of biomechanical aspects in dental crown restorations, contributing valuable insights for clinical applications. [ABSTRACT FROM AUTHOR]

Objective: Given the significant role of retention in the long‐term success of implant‐supported prostheses, this study aimed to compare the retentive strength of three‐unit implant‐supported frameworks manufactured using the conventional, subtractive milling, and 3D printing methods. Materials and Methods: In this in vitro study, two fixture analogs were placed in the mandibular right first premolar and first molar region of a Dentiform model, and two prefabricated abutments were secured in the fixture analogs. A total of 27 three‐unit frameworks were fabricated utilizing wax patterns prepared through conventional, milling, and 3D printing techniques (n = 9 per group). The frameworks were cemented with zinc oxide eugenol and subjected to thermocycling. The retentive strength of each specimen was evaluated through a pull‐out test conducted with a universal testing machine. The data were analysed using one‐way ANOVA and Tukey's post hoc test (p < 0.05). Results: The three groups were found to be significantly different (p = 0.01). While the 3D printing and milling groups were not significantly different (p = 0.99), they yielded significantly higher retentive strength compare to the conventional group (p = 0.02 for 3D printing and p = 0.03 for milling group). Conclusion: The utilization of 3D printing and milling technique for wax pattern preparation significantly increased the retention of the implant‐supported framework, with no statistically significant difference between the two methods. [ABSTRACT FROM AUTHOR]

The clinical success of laminate veneers depends upon their marginal discrepancy (MD) and internal gap (IG). This study aims to compare and evaluate the MD, overall discrepancy (OD), absolute marginal discrepancy (AMD), and IG of 3D-printed (Varseosmile TrinQ and Varseosmile Crown Plus) and computer-aided design and manufacturing (CAD/CAM)-milled (Brilliant Crios) laminate veneers using cone-beam computed tomography (CBCT). Thirty maxillary central incisors were prepared and divided randomly into three groups (n = 10). All teeth were scanned for veneer fabrication: Group PVT teeth with 3D-printed Varseosmile TrinQ, Group PVC teeth with 3D-printed Varseosmile Crown Plus, and Group BCM teeth with Brilliant Crios milled veneers. The specimens with respective veneers were scanned using CBCT, and the sectional images were measured for IG, MD, OD, and AMD. The mean values for MD recorded were 0.27, 0.31, and 0.40 for PVT, PVC, and BCM respectively). The mean values for IG recorded were as follows: PVT group—0.24, PVC group—0.28, and BCM group—0.39, and those for OD were as follows: PVT—0.22, PVC—0.32, and BCM—0.41. Intragroup significance was observed for IG and OD (p = 0.001). Findings revealed that milled veneers have a higher IG and MD than 3D-printed veneers, making them less clinically acceptable. [ABSTRACT FROM AUTHOR]

Background: To evaluate the comprehensive effect of translucency, thickness, cement shades, and background color on the masking ability of resin-matrix ceramic veneer restorations. Methods: Resin-matrix ceramic specimens with 2 translucencies (LT, HT) and 3 thicknesses (0.5, 1.0, and 1.5 mm) were made of Upcera Hyramic (A2 shade). Cement specimens were made of Variolink N in 4 shades (yellow, white, transparent, and bleach XL). Five background specimens were made of IPS Natural Die Material in 5 shades (ND1, ND2, ND3, ND4, and ND5). Color coordinates of 120 subgroups (n = 5) of combined specimens composed of different ceramic, cement, and background specimens were obtained using a spectroradiometer. Color difference (ΔE00) compared with a 4-mm thick specimen of LT and HT ceramics was calculated and four-way ANOVA was used for statistical analysis (α = 0.05). Results: Translucency, thickness, cement shade, background color, and their interaction had significant effects on ΔE00 (p < 0.001). ΔE00 values of HT groups were always higher than that of LT groups and were greater than 1.8 against all background colors. ΔE00 values of LT groups could be achieved to be less than 1.8 with appropriate thickness and cement shade. ΔE00 value decreased with increasing ceramic thickness. The effect of cement shade on ΔE00 had no obvious regularity, but ΔE00 values of bleach XL cement shade group were always lower than other cement shade groups under ND3 and ND5 background color. Conclusions: The masking ability of CAD-CAM resin-matrix ceramics can be simultaneously affected by translucency, thickness, cement shade, and background color. Resin-matrix ceramics with low translucency has a better masking ability than that with high translucency. The masking ability of CAD-CAM resin-matrix ceramics increase with increasing thickness. Cement shade has less impact on the final color of resin-matrix ceramic restorations. [ABSTRACT FROM AUTHOR]

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This study evaluated the changes in surface properties of three resin‐based restorative materials after two laser‐assisted, in‐office tooth bleaching protocols using erbium, chromium: yttrium‐scandium‐gallium‐garnet (Er,Cr:YSGG) or diode (980 nm) lasers. A nanohybrid composite (Enamel Plus HRi), a Bis‐GMA‐free composite (Enamel Plus HRi Bio Function), and a resin‐matrix CAD‐CAM ceramic (Shofu Block HC) were tested. Forty specimens for each material were prepared and divided into four groups (n = 10/group). The control specimens did not undergo any bleaching treatment, whereas group 2 received bleaching with 40% hydrogen peroxide (H2O2), while groups 3 and 4 underwent the same bleaching procedure with the use of diode (980 nm) or Er,Cr:YSGG lasers, respectively. Surface microhardness and roughness measurements were conducted using a Vickers tester and an optical profilometer. Microhardness was lower in bleached specimens, with the nanohybrid composite exhibiting the largest difference from the no bleaching group. For the Bis‐GMA‐free composite the microhardness difference between no bleaching and laser‐assisted bleaching were smaller than seen for the conventional bleaching technique. Surface roughness was higher in bleached specimens, with nanohybrid composite showing the largest differences from the control specimens. The examined laser‐assisted tooth bleaching protocols were found not to impact surface microhardness and roughness of the tested resin‐based specimens and they are deemed suitable for clinical use. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of the deterioration of computer aided design/computer aided manufacturing (CAD/CAM) burs during zirconia milling, on surface roughness, contact angle, and fibroblast viability. Materials and Methods: Ceramic blocks were milled and 75 ceramic disks (8 × 1.5 mm) made and allocated into three groups (n = 25): G1‐brand new 2L and 1L burs, G2‐2L bur at the end of lifetime and brand new 1L bur and G3‐both burs at the end of their lifetimes. Roughness (Ra, Rq, and Rz) was evaluated using a 3D optical profilometer, the contact angle by the sessile drop method and the cell viability of the mouse NIH/3T3 fibroblast, using the Alamar Blue assay at intervals of 24, 48, and 72 h (ISO 10993‐5). Data were analyzed by one‐way ANOVA and Kruskal–Wallis tests (p ≤ 0.05). Results: Roughness increased as the burs deteriorated and G3 (0.27 ± 0.04) presented a higher value for Ra (p < 0.001). The highest contact angle was observed in G3 (86.2 ± 2.66) when compared with G1 (63.7 ± 12.49) and G2 (75.3 ± 6.36) (p < 0.001). Alamar Blue indicated an increase in cell proliferation, with no significant differences among the groups at 24 and 72 h (p > 0.05). Conclusions: The deterioration of the burs increased the surface roughness and decreased the wettability, but did not interfere in cell viability and proliferation. Clinical Significance: The use of custom zirconia abutments represents an effective strategy for single crowns restorations. Our findings suggest that these abutments can be efficiently milled using CAD/CAM burs within their recommended lifetime. [ABSTRACT FROM AUTHOR]

Objectives. The experimental study aims to establish the suitability and reliability of milling and 3D printing processes for acrylic polymethylmethacrylate (PMMA) crown manufacturing by evaluating the internal structure and material integrity through CT scanning analysis and the mechanical properties through indentation experiments. Materials and methods. In the study, samples were made in the form of crowns obtained by milling from Telio CAD blocks (Ivoclar) and by 3D printing using Temp PRINT (GC) material. The samples were analyzed by CT microscanning with the high-resolution equipment Bruker μCT 1272 through which the structure, density and porosity of the materials were assessed. With a nanoindenter test system (G200 Keysight Technologies, Santa Rosa, CA USA) were analyzed the mechanical properties (modulus of elasticity, hardness, stiffness) of the materials of the two sample categories. Results. The results of the experimental study show that both the milling method and 3D printing offer fast and safe ways in obtaining crowns out of PMMA. Micro-CT scans reveal a predominantly uniform internal structure particularly for milling PMMA, with minor variations and localized porosity, indicating a higher level of reliability compared to 3D printing material. The modulus of elasticity values of 3D printing and milling materials are comparable, indicating their ability to provide stability and longevity in dental restorations. Indentation experiments have revealed that 3D printing material has superior rigidity and better resistance to deformation compared to milling material. The higher hardness of the milling material indicates that it has superior resistance to wear, abrasion and surface damage compared to 3D printing material, which provides an additional advantage in terms of long-term durability. Conclusions. The overall conclusion is that the selection of materials for optimal processing will take into account the suitability of the specific application and correlation with the observations of the study, which revealed that the 3D printing material exhibits rigidity and resistance to deformation, and the milling material wear-resistant. [ABSTRACT FROM AUTHOR]

This clinical report summarizes a workflow that introduces two approaches for fabricating a metal framework removable partial denture for a marginal mandibulectomy patient. First, the pre-existing denture was adjusted according to the piezographic technique to determine the optimal configuration for adhering to the available denture space. Second, computer-aided design-computer-aided manufacturing (CAD-CAM) technology was used to fabricate a new removable partial denture by digitally scanning the oral condition and the well-adjusted denture and then using the obtained data to design and fabricate the new denture. These two approaches can help to reduce chair time not only for maxillofacial prosthetic treatment but also for other denture cases. [ABSTRACT FROM AUTHOR]

Advancements in CAD-CAM technology have allowed for a variety of options in implant-supported fixed prosthesis restorations for completely edentulous patients. For patients with severe alveolar bone resorption, zirconia prosthetic restorations that include the gingival portion, such as implant-supported hybrid dentures, are possible, as well as monolithic zirconia prosthetic restorations in the form of crowns. The integration of digital technology in fixed prosthetic restoration using implants enables predictable treatment through diagnosis and virtual surgery by integrating the patient's clinical and radiological information. In this case, the utilization of digital software allowed for the establishment of implants in appropriate positions, considering both the remaining alveolar bone and the final prosthesis. By designing both the maxillary removable prosthesis and the mandibular fixed prosthesis simultaneously in CAD software, bilateral balanced occlusion could be easily achieved. Furthermore, maintaining the initial interocclusal relationship from provisional restorations to final prostheses allowed for convenient transition while ensuring functional and aesthetic satisfaction. [ABSTRACT FROM AUTHOR]

With the increasing use of CAD-CAM (computer-aided design-computer-aided manufacturing) methods for prosthesis fabrication, utilization of virtual articulators in CAD software has also increased. Among the various methods of positioning the maxilla in a virtual articulator, there are techniques that utilize CBCT (cone-beam computed tomography) or facial scans without the use of a facebow. In this case, a full-mouth rehabilitation was planned for a patient who exhibited multiple crown fractures and occlusal plane disharmony through maxillary complete denture and mandibular fixed prosthetic restoration. Radiopaque markers were added to the duplicated maxillary temporary denture to take closed-mouth impression, which was then scanned and positioned on the CBCT. On CBCT, hinge axis connecting the medial poles of both mandibular condyles along with the Frankfort horizontal plane was designated and utilized to perform virtual articulator mounting. Maxillary complete denture and mandibular fixed prostheses were fabricated, resulting in satisfactory aesthetic and functional outcomes. [ABSTRACT FROM AUTHOR]

The coloring process of monolithic dental zirconia caused considerable debate on the possible effects of different coloring methods. The main objective of this study was to investigate the influence of pigments in 3 multilayer 5-mol% yttria partially stabilized zirconia (5Y-PSZ) disks (Lava Esthetic A2 [Zr-AGG_A2] and Bleach [Zr-AGG_BL], both 3M Oral Care, and Katana STML A2 [Zr-NoAGG], Kuraray Noritake). The influence of pigment addition on the translucency parameter (TP00), fracture toughness, Vickers hardness, biaxial strength, and hydrothermal stability was assessed and correlated with the microstructure and phase composition. The pigment composition and distribution were evaluated by light and fluorescence microscopy, electron probe microanalysis, and nano–scanning electron microscopy. The chemical and phase composition and aging behavior were assessed using X-ray fluorescence and X-ray diffraction, respectively, while the aging sensitivity of the pigments was evaluated using micro-Raman spectroscopy. In contrast to Zr-NoAGG, possessing a typical 5Y-PSZ microstructure, the pigment additions in both Zr-AGG_A2/BL zirconia resulted in large yellow and blue fluorescent Er-, Hf-, and Al-containing agglomerates composed of small grains (0.57 µm and 0.38 µm, respectively, vs. 0.92 µm for the surrounding grains) with lower Y2O3 content. Zr-AGG_A2 had the lowest aging resistance, with transformation degradation occurring exclusively within the pigment agglomerates. All zirconia grades had a high Y2O3 content (4.2%–5.7 mol%) tetragonal ZrO2 phase and a high (42%–55 wt%) cubic ZrO2 phase content. Although no statistical differences were measured for hardness and toughness, Zr-NoAGG had a significantly higher TP00, higher flexural strength, and lower mechanical reliability compared to both Zr-AGG_A2/BL zirconia. The rare-earth oxide-containing zirconia agglomerates that were added as pigments to the multilayered monolithic Zr-AGG_A2/BL zirconia are the cause for their lower optical and mechanical properties and reduced aging resistance. [ABSTRACT FROM AUTHOR]

Purpose: To explore the clinical application of one‐piece polyetheretherketone (PEEK) removable partial dentures (RPDs) fabricated using a novel digital workflow and to evaluate their weights and fits in vivo and patient satisfaction. Materials and Methods: Fifteen cases with posterior partially edentulous situations were selected, and each patient received two types of RPDs, including a novel digital workflow (test group) and a conventional workflow (control group). For the test group, one‐piece RPDs were designed through three‐dimensional (3D) methods by scanning stone casts and fabricated by milling PEEK discs. Each RPD was weighed. The gaps between the oral tissue and RPDs in each group were duplicated using a polyvinylsiloxane (PVS) replica and measured by 3D analysis. A visual analog scale (VAS) was used to evaluate the patient's satisfaction. Paired t‐tests were used to compare the differences in the weight, the gaps of each RPD, and VAS values between the two groups. One‐way analysis of variance tests was used to compare the differences in the gap among different components in each group. Results: The RPD in the test group weighed less than that in the control group (p < 0.01). No statistically significant differences in the gaps of denture bases and rests (p > 0.05) were found between the two groups, but the gaps of major connectors in the test group were significantly smaller than in the control group (p < 0.05). The VAS scores for comfortableness and masticatory efficiency were not significantly different between the two groups (p > 0.05) but the scores for the aesthetic appearance of the clasps in the test group were significantly higher than that in the control group (p < 0.05). Conclusions: One‐piece PEEK RPDs manufactured using a novel digital workflow weighed less than conventional RPDs and exhibited a clinically acceptable internal fit. Although the aesthetic appearance of the PEEK clasps was superior to the control, there is still room for improvement. [ABSTRACT FROM AUTHOR]

Purpose: This systematic review aims to compare clinical outcomes of digital dentures with conventional dentures. Materials and Methods: This study followed the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines and was registered in Prospero. The formulated population, intervention, comparison, outcome (PICO) question was "What is the clinical outcome of digital versus conventional complete dentures (CDs) in edentulous patients?". The search strategy used three main electronic databases and an additional manual search was completed in August 2023 by following an established search strategy. Initial inclusion was based on titles and abstracts, followed by a detailed review of selected studies, and clinical studies that evaluated the clinical outcome of digital (milled or 3D‐printed) versus conventional CDs were included. A qualitative analysis for clinical studies was used to assess the risk of bias. The certainty of the evidence was assessed according to the grading of recommendations, assessment, development, and evaluations (GRADE) system. In addition, a single‐arm meta‐analysis was performed to evaluate the retention between digital versus conventional CDs. Results: The initial search yielded a total of 947 articles, out of which 19 were selected for a comprehensive review, and six met the eligibility criteria to be included in this systematic review. The computer‐aided design and computer‐aided manufacturing (CAD‐CAM) CDs showed increased retention, no relevant differences in oral health‐related quality of life (OHRQoL), and shorter working time compared to conventional dentures. Two studies were eligible for meta‐analysis; retention was significantly better among CAD‐CAM fabricated dentures (standardized mean difference [SMD] 0.501) than conventional dentures. The heterogeneity between studies was high (95% CI: 0.049–0.952). Conclusions: Clinically, both the milled and the 3D‐printed CD fared better than conventional dentures in terms of retention, reduction in the number of appointments, improved patient comfort, and improved predictable maintenance of the denture. Patients' perceptions and satisfaction were independent of the digital and conventional fabricated dentures. [ABSTRACT FROM AUTHOR]

Squamous cell carcinoma is a common malignant condition affecting the oral cavity and may involve the surrounding maxillofacial regions. Treatment commonly involves resection of the tumor, followed by prosthetic rehabilitation of the resection defect. This clinical report presents a 62‐year‐old Asian male patient who had previously undergone surgical resection, resulting in a post‐surgical Aramany Class II maxillary defect. The patient's medical history included severe trismus, characterized by restricted mouth opening, as well as a diagnosis of maxillary sinus verrucous squamous cell carcinoma. This report provides a comprehensive account of the rapid fabrication of an interim obturator using digitally assisted dentistry techniques. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the overall adaptation and retention of class I cobalt‐chromium (Co‐Cr) removable partial denture (RPD) frameworks using three different computer‐aided design and computer‐aided manufacturing (CAD‐CAM) technologies: Indirect wax milling with lost wax technique (LWT), direct milling, and selective laser melting (SLM) technique. Materials and Methods: An educational maxillary stone model (Kennedy class I) was scanned after preparing rest seats to create a resin model. The resin model was scanned, and the RPD framework was digitally designed and saved as a standard tessellation language (STL) file. Twenty‐four Co‐Cr RPD frameworks were then constructed and divided into three groups (n = 8) based on fabrication technique: Group A (indirect wax milling with LWT), Group B (direct milling), and Group C (selective laser melting). In Group A, the STL file was used to mill the design from castable resin blanks which were then cast by the LWT. In Group B, the STL file was used to mill the design from the Co‐Cr blank directly. Finally in Group C, the STL file was used to print the design from Co‐Cr powder using SLM 3D printed technique. Geomagic Control X software was used to measure the overall adaptation of the fabricated RPD frameworks, Retention was also tested using a universal testing machine. One‐way Analysis of Variance (ANOVA) test was used to compare the three groups then the Tukey HSD post‐hoc test was used for pair‐wise comparisons. The significance level was set at p ≤ 0.05. Results: Regarding the overall adaptation, Group B (0.71 ± 0.02 mm) showed significantly higher adaptation than Group A (0.96 ± 0.06 mm) and Group C (1.05 ± 0.16 mm). Regarding retention, Group B (2.03 ± 0.34 N) showed significantly higher retention than Group A (1.00 ± 0.13 N) and Group C (0.78 ±0.17 N). Conclusion: Based on the findings of this in vitro study, Co‐Cr RPD frameworks fabricated by direct milling technique revealed the best adaptation and retention. [ABSTRACT FROM AUTHOR]

Background and Objectives: Advances in dental materials and CAD-CAM technology have expanded crown options in primary teeth due to their improved appearance and mechanical properties. Thus, this study aimed to assess the enamel wear and fracture resistance of prefabricated, milled, and 3D-printed esthetic pediatric crowns. Materials and Methods: The study involved 60 extracted maxillary second primary molars and 60 3D-printed resin dies, divided into six groups based on different crown materials (n = 10): prefabricated zirconia, prefabricated composite, milled composite, milled resin matrix ceramic, milled PEEK, and 3D-printed resin. Prefabricated crowns were selected after the preparation of the typodont mandibular second primary molar tooth, while milled and 3D-printed crowns were custom produced. The specimens underwent mechanical loading of 50 N at 1.6 Hz for 250,000 cycles with simultaneous thermal cycling. The 3D and 2D wear amounts were evaluated by scanning the specimens before and after aging. Then, the fracture resistance and failure types of the restorations were recorded. Results: The results showed that the milled PEEK group had superior fracture resistance compared to the other groups, while prefabricated zirconia crown group had the lowest value. Milled resin matrix ceramic crown group displayed the lowest 3D wear volume, while 3D-printed crown group showed the highest 2D wear. Conclusions: The restorative material type did not have a significant effect on the wear of primary tooth enamel. The fracture resistance of the tested materials differed according to the material type. Although the milled PEEK group showed the highest fracture resistance, all tested materials can withstand chewing forces in children. [ABSTRACT FROM AUTHOR]

Background: Occlusal veneer had been evaluated for mechanical properties using lithium disillicate. However, studies evaluating the mechanical properties of occlusal veneer with different preparation designs and ceramic materials are lacking. So, this in vitro study aimed to evaluate the fracture resistance of occlusal veneers with two designs fabricated from two different ceramic materials. Material and methods: Fourty mandibular third molars were distributed to 2 groups (n = 20) according to preparation design: group (O) anatomical occlusal reduction and group (OA) anatomical occlusal and 1 mm axial reduction. Each group was additionally subdivided into two subgroups (n = 10) according to ceramic materials; in subgroup X, lithium disilicate (e.max CAD, Ivoclar AG, Schaan, Liechtenstein) was used, and in subgroup S, zirconia-reinforced lithium silicate (ZLS) (Vita Suprinity, VitaZahnfabrik, Bad Säckingen, Germany) was used. All specimens were cemented with a light-cure resin cement (Choice 2, Bisco, Schaumburg, USA). 5000 thermocycles were applied to all specimens with both temperatures of 5 °C and 55 °C in two water baths; the dwell time was 30s at each bath, and the transfer time was 10s. Then all specimens were subjected to a fatigue simulation under dynamic loading of 200 N for 250,000 cycles. A universal testing machine (5500R/1123, Instron, Norwood, USA) was used to evaluate the fracture strength with a crosshead speed of 1 mm/min. All data were analyzed statistically by using a two-way ANOVA, and for some violations of assumptions, these results were compared with those obtained by the nonparametric test (Scheirer Ray Hare) (α = 0.05). Results: A statistically significantly higher fracture resistance in the 'OA' (3389 N) compared to the 'O' (2787 N) group regardless of the ceramic material (P <.001) and a statistically significantly higher fracture resistance in the 'X' (3295 N) compared to the 'S' (2881 N) regardless of the preparation design (P =.015). Conclusions: For occlusal veneers, all preparation designs and materials (such as Vita Suprinity and e.max CAD) had clinically acceptable fracture resistance values that were greater than the maximal biting forces. On the other hand, the e.max CAD with occlusal veneer, including axial reduction design, demonstrated the maximum fracture resistance value. Finally, no relationship between fracture strength and mode of failure was found. Clinical implications: Proper preparation design and the use of dental materials with high fracture resistance are key factors in extending the life of occlusal veneer restorations. The highest fracture resistance was demonstrated by lithium disilicate glass-ceramic occlusal veneers with axial preparation, which may increase the clinical longevity of teeth restored with occlusal veneers. [ABSTRACT FROM AUTHOR]

The socket is the most important, patient-specific element of a prosthesis. Conventionally, the process of making a custom socket involves manually rectifying a plaster model of the residual limb. This process is time-consuming and often inconsistent among prosthetists because it is based on implicit knowledge. Hence, the aim of this work was to describe a novel process of generating a prosthetist-specific, digital "global" template and to illustrate that it can be automatically applied to rectify the shape of a transtibial residual limb. The process involved (1) the acquisition of a "training" dataset of unrectified and rectified positive models through manual data collection and digital 3D scanning, and (2) the unsupervised learning of the prosthetist's rectifications by an artificial intelligence (AI) algorithm. The assessment of the process involved (1) evaluating whether the rectification rule learned by the AI was consistent with the prosthetist's expectations, and (2) evaluating the template feasibility by applying the AI rectification process to a new residual limb and comparing the results to the prosthetist's manual rectification for the same residual limb. The results suggest that the AI-rectified positive was consistent with the approach described by the prosthetist, with only small radial and angle errors and similar dimensions (volume and cross-sectional perimeters) as the hand-rectified positive. This study provides a proof-of-concept of the ability to integrate an AI algorithm into the fabrication process for transtibial prosthetic sockets. Once refined, this approach may provide a time-saving tool for prosthetists by automatically implementing typical rectifications and providing a good starting socket fit for individuals with amputation. [ABSTRACT FROM AUTHOR]

The precision of the luting protocol plays a crucial role in the success and survival rate of porcelain laminate veneers (PLVs). This in vitro study aimed to evaluate the influence of different luting techniques on the positioning of PLVs through a novel, noninvasive, scanning-based technique. A total of 45 ceramic PLVs were milled and cemented on human tooth replicas. Specimens were divided into three groups of 15, each subjected to a different luting protocol: flowable composite (Group A), dual-cure resin cement (Group B), and preheated composite resin (Group C). After luting procedures, specimens were scanned, and every STL file was superimposed with the original tooth design in Geomagic Control X version 2022.1 software to assess linear (incisal, mid, cervical) and angular discrepancies. Statistical analysis was performed using one-way ANOVA, Tukey's HSD tests, and regression analysis. ANOVA results showed no statistically significant differences for incisal (F = 0.327, p = 0.723), mid (F = 0.287, p = 0.752), cervical (F = 0.191, p = 0.827), and angular (F = 0.026, p = 0.975) measurements. Tukey's HSD post hoc tests confirmed the lack of significant pairwise differences between groups. The study demonstrated that the type of luting agent used does not significantly impact the final position of PLVs. This suggests flexibility in the choice of luting agents without compromising the accuracy of PLV placement. [ABSTRACT FROM AUTHOR]

This in vitro investigation aimed to compare the trueness, precision, internal fit, and marginal adaptation of Varseo Smile Crown Plus (VSCP), CROWNTEC (C), and milled Enamic crowns (E) using a 5-axis dental milling machine (prograMill PM7). 39 crowns (VSCP, E, C; n = 13) were designed and fabricated. Internal/marginal adaptation, precision, and trueness were assessed via die scans with/without a fit checker. Dimensional discrepancies were determined by superimposing the scans. One-way ANOVA (α = 0.05) analyzed the results. No significant differences were found in internal fit or marginal adaptation between groups. However, group E exhibited the best fit (axial: 82.9 µm). Trueness differed significantly (p < 0.05) across all groups and areas. Group E had the highest trueness (intaglio: 25.8 µm), while VSCP had the lowest (marginal: 31.9 µm). Precision varied significantly within the occlusal area of printed groups (highest for C: 17.8 µm) and the marginal area between printed/milled (VSCP vs. E) and C vs. E (lowest for E: 20.5 µm, highest for VSCP: 27.9 µm). In conclusion, both milled and 3D-printed crowns achieved comparable internal fit and marginal adaptation. However, group E displayed superior fit and trueness. While C exhibited higher occlusal precision, E had higher marginal precision. These findings suggest the potential for 3D-printed hybrid polymer crowns, warranting further investigation. [ABSTRACT FROM AUTHOR]

Background: There is a lack of studies comparing the dimensional accuracy and color stability of denture base resins made using computer-aided design and computer-aided manufacturing (CAD-CAM) milling, 3-dimensional (3D) printing, and conventional denture processing techniques. This makes it challenging to determine the best method to fabricate complete dentures. The objective of this in vitro investigation was to assess and contrast the color stability and dimensional accuracy of denture base resins that were 3D printed and CAD-CAM milled, both before and after aging by thermocycling using digital surface matching technology and a benchtop laser scanner without using a spray, to optimize adaptation of the denture base and cast to minimize any imperfections and to evaluate the impact of the denture cleansing solution on the stability of color. Methods: Evaluation of the dimensional accuracy (n = 27) was completed on a sectional maxillary stone cast using a digital 3D-surface matching software before and after 5000 thermocycles. A spectrophotometer was used to measure the color change (△E00) of all disc specimens (N = 54) before and after 500 thermocycles and immersion in denture cleansing solution for 30 cycles (3 min each) daily for 6 days. The Kruskal Wallis test, Dunn's post hoc test, Tukey's test with Bonferroni adjustment, one sample t test and independent t test were used to statistically analyze the data (α < 0.05). Results: Thermocycling decreased the dimensional accuracy of the heat polymerized group at all 5 locations and the 3D-printed group at locations 1, 3 and 5 (P >.05), while it had no significant difference on the CAD-CAM milled group at all locations (P <.05). The color change (△E00) was lowest in the CAD-CAM milled group, moderate in the heat-polymerized group and highest in the 3D-printed group. After immersion in denture cleanser, the color change (△E00) was significantly higher in the 3 groups compared with after thermocycling (P >.001). Conclusions: CAD-CAM milled resins had the highest dimensional accuracy and the best color stability, conventional heat polymerized acrylic resins showed moderate change in dimensional accuracy and color stability, while the 3D- printed resin had the lowest dimensional accuracy and color stability after aging by thermocycling. [ABSTRACT FROM AUTHOR]

Background: Decreased salivary flow can make the patients uncomfortable with their complete dentures and affects the retention of the dentures. Milling and 3D printing have become an alternative to conventional denture construction techniques. The goal of this study was to evaluate the effect of conventional and digital techniques of the complete denture construction on the denture surface wettability with distilled water and saliva substitute before and after thermocycling. Methods: A total of 30 specimens were utilized in the present study. Specimens were divided according to the construction techniques into 3 groups (n = 10 each). Group I: Heat-polymerized polymethylmethacrylate (PMMA) group, group II: Milled group, and group III: 3-dimensional (3D)-printed group. All the specimens were subjected to 2000 cycles of thermal aging in a thermocycler. The wettability of all specimens to water and saliva substitute was measured via a contact angle goniometer (Olympus TGHM, Rame-hart Inc, USA) before and after thermocycling. Descriptive statistical analysis, plots, and the Shapiro-Wilk test were used to verify normality for each variable. One-way ANOVA was used to compare the 3 study groups, while paired samples t-test was used to compare the differences within each group (P <.05). Results: The smallest contact angle of drop of water to the denture base specimens before and after thermocycling were recorded in the milled group (53.0 ± 4.77 and 50.27 ± 2.30, respectively), followed by the heat polymerized PMMA group (85.65 ± 4.71 and 65.06 ± 2.27, respectively), and the 3D-printed group (91.34 ± 6.74 and 90.86 ± 8.57, respectively). While the smallest contact angle of drop of saliva substitute to denture base specimens was recorded in the milled group (56.82 ± 2.29 and 34.85 ± 7.51, respectively), followed by the 3D-printed group (72.87 ± 4.83 and 58.14 ± 9.58, respectively) and the heat polymerized PMMA group (83.62 ± 4.12 and 67.82 ± 4.93, respectively). There was statistically significant difference between the groups (P <.05). A significant decline in the average contact angle of drop of saliva has been reported in all groups after thermocycling. The contact angle values differed significantly between saliva substitute and distilled water in both 3D-printed and milled groups after thermocycling (P <.001). Conclusions: The milled denture base material presented the best wettability to water and saliva substitute than the 3D-printed and the heat-polymerized PMMA materials. Saliva substitutes improve the wetting ability of denture base materials manufactured by CAD/CAM compared with water. [ABSTRACT FROM AUTHOR]

The quest for an esthetically pleasing smile is a key driver in seeking dental interventions aimed at achieving a more balanced and harmonious appearance. The purpose of this report is to discuss the restoration of conical lateral incisors in an 11-year-old patient. The treatment approach employed direct composite resin restorations associated with the Digital Smile Design (DSD) technology. The use of composite resins is the technique of choice for re-anatomizing conical teeth due to the material's versatility and low cost. In this case, the technique associated with the digital workflow resulted in the efficacy of esthetic restorations. DSD contributes to greater predictability of dental treatment, comfort, safety and efficiency. [ABSTRACT FROM AUTHOR]

Background: Contemporary fixed orthodontic appliances are shifting from non‐customized pre‐adjusted appliances to custom‐designed and printed appliances with novel digital setup systems. We are one step closer to precision dentistry and orthodontics using personalized mechanics and custom appliances. However, despite the evidential enhancement and other improvements to fixed appliances, tooth movement is still limited to five degrees of freedom. Opening or closing spaces still requires manually placing elastomeric chains or coil springs. Aim: In this article, we aimed to demonstrate how advancements in CAD/CAM technology, reverse engineering, and digital customization are helping orthodontics constantly evolve, enabling treatment with enhanced esthetics and minimal compliance. The clinical system (InBrace®, Irvine, CA) described in this article uses a patient‐specific, digitally designed multiloop NITI wire that delivers friction‐free, light, and continuous forces and activates automatically whenever the malocclusion deviates from the digital setup. Conclusion: Through digital customization, InBrace allows for automated tooth movement in all six degrees of freedom, including space opening or closure, via programmed non‐sliding mechanics. Clinical Significance: Precision orthodontics and personalized treatment have been significant developments in orthodontics recently. This article focuses on how a technologically advanced lingual appliance system could achieve targeted cosmetic results methodically via automation and personalization. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to assess the influence of translucent monolithic versus bilayered crowns and whether the use of a CoCr base abutments affects the fatigue and fracture resistance of screwed implant‐supported single crowns with external connections under mechanical cycling. Materials and Methods: Fifty specimens were divided into groups: (1) metal–ceramic (MC) crown, (2) veneered zirconia crown (Zr), (3) veneered zirconia crown with a CoCr base abutment (ZrB), (4) monolithic translucent zirconia crown (MZr), and (5) monolithic translucent zirconia crown with a CoCr base abutment (MZrB). Specimens underwent mechanical cycling (5 × 106 cycles; 150 N) evaluating fatigue resistance (number of failures) and those that failed were subsequently subjected to fractographic analyses (stereomicroscope and scanning electron microscope) to evaluate failure location and area, and maximum fracture load was also measured. Results: The failure‐related survival rate (100%) and maximum fracture resistance of the MZrB were significantly higher than those of MC and Zr (50%; p < 0.05). There were no significant differences in the failure rate and fracture resistance when a CoCr base abutment was used or not in the translucent monolithic Zr groups (p > 0.05;MZrB vs. MZr). Failure location, with MC crowns' fractures, noted at the screw area (p = 0.043), while all‐ceramic crowns were mostly in the cuspid and to failure area, the Zr group had the largest mean (15.55 ± 9.17 mm2) among the groups, significant difference only when compared with MC (1.62 ± 0.81 mm2) (p = 0.025). Conclusions: Translucent monolithic zirconia crowns exhibited significantly higher fatigue and fracture resistance compared with conventional MC and bilayered crowns. Clinical Significance: The appropriate choice of material and manufacturing technique is crucial for predicting the higher clinical performance of single crowns. Enhanced mechanical resistance in terms of fatigue and fracture resistance can be achieved by replacing MC and bilayered restorations with computer‐aided design and computer‐aided manufacturing monolithic zirconia. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of acidulated phosphate fluoride (APF) application on filler-free polymethyl methacrylate (PMMA)-based resin blocks for computer-aided design/computer-aided manufacturing (CAD-CAM), focusing on their use in pediatric crowns. Three types of PMMA-based blocks for CAD-CAM were evaluated, and a composite resin block for CAD-CAM was used as a control. Statistical analysis (p<0.05) of the data revealed that all PMMA-based blocks showed significantly higher gloss levels than the composite resin blocks. Two PMMA-based blocks also demonstrated significantly lower Ra and Sa values. SEM images showed no irregular changes in the surface properties of the PMMA-based blocks compared to those of the composite resin block. These results are significant in meeting the increasing demand for esthetic restorative treatments in pediatrics, where APF is commonly used for caries prevention. PMMA-based resin blocks for CAD-CAM are an effective alternative to prevent esthetic degradation from gloss reduction and plaque accumulation. [ABSTRACT FROM AUTHOR]

This paper introduces a developed CAD-CAM program that is named as 'DNC.GARM.DOBBY WEAVING DESIGN'. It was developed using JAVA SE. The software DNC.GARM.DOBBY WEAVING DESIGN is available for individual studies in designing dobby patterns and it generates machine readable files for semi-automated sampling looms manufactured by Gulas Weaving Machines Company (Istanbul/Türkiye). Pattern design and development tools are used in program menu enabling to design the weave with warp/weft colors also. The weave pattern, drafting and lifting plan can be generated manually or automatically. This article represents technical information, features and usage of the developed software DNC.GARM.DOBBY WEAVING DESIGN for designing and production planning of woven patterns and generating the machine readable files for sampling looms. [ABSTRACT FROM AUTHOR]

The aim of this report was to digitize traditional denture relining using a digital duplication method, in addition to assessing the wear resistance of three‐dimensional (3D) printed denture teeth. A complete denture was relined using light body impression. The denture with impression was scanned yielding a standard tessellation language file that was designed to print the denture base and teeth. The printed teeth were fitted into the sockets of the printed denture base and then bonded using auto‐polymerized acrylic resins, followed by finishing and polishing. Dentures were inserted and fit and occlusion were adjusted as needed, and the patient was scheduled for follow‐up appointments at one week, three months, and six months. At each follow‐up visit, dentures were scanned using a 3Shape E3 desktop scanner and scans were superimposed. The occlusal wear was assessed in reference to the first scan after the denture insertion visit. The accuracy of the intaglio surface of dentures was within clinically acceptable limits. The clinical evaluation of inserted dentures in terms of retention, occlusion, esthetic, and patient satisfaction was encouraging. Using digital duplication, conventional dentures could be relined. The advantages of digital records include eliminating polymerization dimensional changes, and reducing cost and clinical time by minimizing the number of visits, which is particularly helpful with geriatric patients. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores. Methods: Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (n = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick® glass fiber post-core (Group GF), zirconia post-core (Group Z), metal (Cr-Co) post-core (Group M), PEEK post-core without filler (Group UP), PEEK post-core with 20% TiO2 Filler (Group TP), and post-core with 20% ceramic filler (Group CP). Following the application of posts to post spaces, copings were created and cemented on the samples. With the universal tester, a force was applied to the long axis of the tooth with a slope of 135°. The mean fracture strength (N) between the groups was statistically evaluated using one-way ANOVA, and pairwise mean differences were detected using post hoc Tukey's HSD test among the groups. Results: According to the results of the statistical analysis, a significant difference was found between the groups in terms of mean fracture resistance (p < 0.05). Group Z (409.34 ± 45.72) was significantly higher than Group UP (286.64 ± 37.79), CP (298.00 ± 72.30), and TP (280.08 ± 67.83). Group M (376.17 ± 73.28) was significantly higher than Group UP (286.64 ± 37.79) and Group TP (280.08 ± 67.83). There were no statistically significant differences between the means of the other groups (p > 0.05). Among all the groups, Group Z exhibited a higher prevalence of repairable failure modes, while the rest of the groups predominantly experienced irreparable failure modes. Conclusion: In our study, zirconia and metal post-core samples showed higher average fracture strength values than PEEK post-cores groups. Repairable failure modes were more common in the zirconia post-cores, whereas the opposite was observed in the other groups. Further experimental and clinical trial studies are needed before PEEK materials can be used as post materials in the clinic. [ABSTRACT FROM AUTHOR]

The aim of this in vitro study is to compare the performance of digital and conventional methods in the manufacture of single copings in terms of the internal and marginal fit. Twenty‐four prefabricated titanium Cone Morse Exact abutments of the lateral anatomical type were used to manufacture 24 lithium disilicate copings in the CAD‐CAM Ceramill (n = 12) and heat‐press (n = 12) systems. The copings were cemented using a self‐adhesive resin cement (RelyX U‐200; 3M ESPE) and then cut vertically. The cement line was photographed using an optical microscope at ×100 and ×200 magnification and then the internal and marginal regions were measured. The mean values of fits, for the CAD‐CAM and heat‐press techniques, respectively, were (μm): angular regions, 81.8 and 75.3; linear regions, 63.1 and 60.1; incisal regions, 171.1 and 114.7; marginal discrepancy, 74.1 and 75.2; and absolute marginal discrepancy, 99.5 and 96.2. MANOVA test showed that there is an effect of the techniques on the regions (p <.05). The effects of laboratories and the interaction between laboratories and techniques on the regions were not statistically significant (p >.05). The techniques evaluated presented clinically acceptable results for the marginal fit. However, the conventional method performed better for the internal fit. Research Highlights: Scientific evidence regarding the methods of making prosthesis can help the dental professional in decision‐making. Digital and conventional methods is both good in the manufacture of single copings in terms of the internal and marginal fit. [ABSTRACT FROM AUTHOR]

Background: To investigate the effect of zirconium dioxide nanoparticles (ZrO2NPs) on the shear bond strength (SBS) of hard denture lines bonded to different denture base resins. Methods: Five different denture bases were used in this study: conventional heat-cured resin, IvoCad, AvaDent, NextDent, and FormLabs, in acrylic specimens of 10 × 10 × 2.5 mm3 (N = 150, n = 10). Specimens were centered at the bottom of a silicon mold to create an auto-polymerized holder. Three major groups of reline material were used: no ZrO2NPs (control), 2 wt.%, and 4 wt.% ZrO2NPs. Reline was bonded to the resin surface using a customized jig. After polymerization, specimens were stored in distilled water, and 5000 thermal cycles were performed. Each specimen was fixed to an Instron machine, and SBS was tested using a blade loaded (1 mm/min) at the resin interface until failure. Data was collected and analyzed using two-way ANOVA and post hoc Tukey test (α = 0.05). Results: AvaDent showed the highest SBS when compared with other denture base materials (p < 0.001) except for IvoCad. The addition of ZrO2NPs significantly decreased the SBS of AvaDent (p = 0.003) and IvoCad (p = 0.001), while heat polymerized resin, Formlabs, and NextDent showed no significant change in SBS (p > 0.05). Conclusion: CAD-CAM milled denture base resin showed higher SBS with pure denture reline. The addition of ZrO2NPs decreased the SBS of reline with CAD-CAM milled denture base resins but did not change bond strength with 3D printed and conventional denture base resins. [ABSTRACT FROM AUTHOR]

Abstract Background The purpose of this pilot in-vitro study was to assess the effect of sterilization on the intra-implant axis, inter-implant axis, intra-implant distance and inter-implant distance of three implants in a straight line by using laboratory scanner (LBS) versus intra-oral scanner (IOS) with intra-oral scan bodies (ISB). Methods: A printed 3D model with three internal hex analogs in the positions 15#,16#,17# was used. Zirkonzhan (ZZ) intra-oral scan body (ISB), two-piece titanium was used. The ZZ ISBs were scanned by 7 Series dental wings (LBS) and 30 times by Primescan (IOS) pre sterilization and 30 times post sterilization. For each scan (pre and post) stereolithography (STL) file was created and a comparison between all the scans pre sterilization and post sterilization were superimposed on the laboratory scan by using a 3D analyzing software. A Kolmogorov-Smirnov test performed followed by Wilcoxon Signed Ranks tests. (p

Abstract Background While many denture base materials are currently available on the market, little data exists regarding their dimensional stability after exposure to the oral environment. This study aimed to evaluate the effect of thermocycling on the trueness and precision of milled, 3-dimensional (3D)-printed, and conventional digitally fabricated complete denture bases (CDBs). Methods A completely edentulous maxillary stone model was scanned to generate a standard tessellation language (STL) file; this was imported into metal-milling-machine software (Redon Hybrid CAD-CAM metal milling machine, Redon, Turkey) to produce a metal model for fabricating 30 CDBs. These were divided into three groups (n = 10 in each) according to the construction technique: group 1, CAD-CAM milled CDBs; group 2, 3D-printed CDBs; and group 3, conventional compression molded CDBs. All CDBs were scanned after fabrication and evaluated before and after thermocycling using superimposition. The data were analyzed using a one-way ANOVA, Tukey’s post hoc test, and a paired t-test. Results The level of trueness between the CAD-CAM milled, 3D-printed, and compression molded CDBs showed significant differences before and after thermocycling (P

Abstract Background Marginal misfit and surface roughness of customized implant abutments is critical for restorative success. However, little is known about the comparison of misfit and surface roughness of CAD-CAM Zirconium oxide (ZrO), selective laser melting (SLM) Cobalt Chrome (CoCr) and preformed abutments. The aim of the study is to investigate the relation of misfit and micro-roughness of selective laser melting (SLM), preformed and CAD-CAM implant abutments. Methods Thirty internal connection, endosseous dental implants (Ø 4.0 mm x 10 mm, Dentium) were mounted in Polymethyl methacrylate vertically. Ten preformed Titanium alloy (Ti) abutments with 1 mm soft tissue height and Ø 4.5 mm were included as controls. Ten each of Y-TZP and SLM-CoCr, abutment/crowns were fabricated using CAD-CAM milling (CAD-CAM-ZrO) and SLM techniques. Surface micro-roughness (Ra) of the fabricated implant abutment/crown was evaluated with a 3D optical non-contact microscope. All implant restorations were torqued to implants (30 Ncm) using a Tohnichi BTGE digital torque gauge and were analyzed with Bruker micro-CT (Skyscan 1173) to detect micro-gaps at pre-selected points at implant abutment interface. The Ra and misfit data were compared using ANOVA, Tukey-Kramer, Kruskal-Wallis test and Pearson correlation (p 0.05). Misfit was significantly higher in Y-TZP samples compared to SLM-CoCr (p = 0.031) and preformed Ti abutments (p = 0.01). Preformed Ti abutments showed significantly lower misfit compared to SLM-CoCr abutments (p = 0.01). A positive linear correlation was observed between the surface roughness (Ra) and vertical misfit (r = 0.61, p

Abstract Background Digitally fabricated dentures may require relining due to continual alveolar ridge resorption. However, studies evaluating the tensile bond strength (TBS) of digitally fabricated dentures bonded to denture liners are lacking. This study aimed to evaluate the TBS of autopolymerized, heat-polymerized, milled, and 3D printed denture base materials bonded to 2 acrylic-based and 2 silicone-based denture liners, both before and after thermocycling. Additionally, the impact of thermocycling on the TBS were also evaluated. Methods The TBS of 4 different denture base materials (Palapress (PL), Vertex Rapid Simplified (VR), Smile CAM total prosthesis (SC), and NextDent denture 3D+ (ND)) bonded to 2 acrylic-based (GC Soft-Liner (GC) and Tokuyama Rebase II (RB)) and 2 silicone-based (Ufi Gel P (UP) and Sofreliner Tough M (ST)) denture liners were tested. Specimens (n = 8) were divided into non-thermocycling and thermocycling groups. Non-thermocycling specimens were tested after 24-hours water immersion, while thermocycling specimens were underwent 5000 cycle and were immediately tested. Mode of failure was examined under a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey HSD tests (α = 0.05), and independent samples t test (α = 0.05) for TBS between non-thermocycling and thermocycling groups. Results For the non-thermocycling groups, within the same denture liner material, no significant differences were found between denture base materials, except the ND + RB group, which had significantly lower TBS. For the thermocycling groups, within the same denture liner material, the TBS in the PL group exhibited the highest and the ND group exhibited the lowest. Within the same denture base material, in both non-thermocycling and thermocycling groups, the TBS in the ST group exhibited the highest; in contrast, that in the GC group exhibited the lowest. No significant differences were observed in TBS between non-thermocycling and thermocycling groups, except for denture base materials bonded to the ST group, SC + UP, and ND + UP groups. Conclusions Milled denture base can be relined with acrylic-based or silicone-based denture liner. However, cautions should be exercised when relining 3D printed denture base. Thermocycling did not affect TBS between acrylic-based denture liners and denture bases. In contrast, it affected the bond between silicone-based denture liner and denture base.

Currently, dentistry tends to be more conservative, preserving dental tissue. The use of direct restorations and indirect partial restorations in composite resin, associated with biomimetic protocols, are examples of minimally invasive procedures. Teeth with extensive cavities and subgingival marginal endings are challenges for clinical practice, and in the search for more conservative protocols, deep margin elevation (DME) may be indicated. This work aims to demonstrate, through a clinical case, the importance of DME associated with the milled indirect restoration in composite resin, using the CAD-CAM system, in a tooth with a margin located beyond the cement-enamel junction (CEJ). The present case report described the restorative treatment of the upper left second premolar, which initially presented extensive caries under a composite resin restoration on the occlusal and mesial surfaces; and, after its removal, had the cervical margin of the mesial surface allocated subgingivally. The treatment option was composite resin DME, followed by endodontic treatment, sealing of the canal entrances, composite resin core build-up, and final restoration type onlay, also in composite resin, produced through the digitally assisted design and manufacturing system (CAD-CAM). The proposed treatment demonstrated that DME allows for the perfect adaptation of the restoration directly to the tooth, eliminating the need for clinical crown lengthening (CCL). Thus, an effective, quick treatment with lower comorbidity and reduced financial cost to the patient was achieved. After four months, the clinical and radiographic evaluation of the restoration showed good marginal adaptation, pleasant aesthetics, good polishing, and gingival health, with no signs of inflammation.

Background: Digitally fabricated dentures may require relining due to continual alveolar ridge resorption. However, studies evaluating the tensile bond strength (TBS) of digitally fabricated dentures bonded to denture liners are lacking. This study aimed to evaluate the TBS of autopolymerized, heat-polymerized, milled, and 3D printed denture base materials bonded to 2 acrylic-based and 2 silicone-based denture liners, both before and after thermocycling. Additionally, the impact of thermocycling on the TBS were also evaluated. Methods: The TBS of 4 different denture base materials (Palapress (PL), Vertex Rapid Simplified (VR), Smile CAM total prosthesis (SC), and NextDent denture 3D+ (ND)) bonded to 2 acrylic-based (GC Soft-Liner (GC) and Tokuyama Rebase II (RB)) and 2 silicone-based (Ufi Gel P (UP) and Sofreliner Tough M (ST)) denture liners were tested. Specimens (n = 8) were divided into non-thermocycling and thermocycling groups. Non-thermocycling specimens were tested after 24-hours water immersion, while thermocycling specimens were underwent 5000 cycle and were immediately tested. Mode of failure was examined under a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey HSD tests (α = 0.05), and independent samples t test (α = 0.05) for TBS between non-thermocycling and thermocycling groups. Results: For the non-thermocycling groups, within the same denture liner material, no significant differences were found between denture base materials, except the ND + RB group, which had significantly lower TBS. For the thermocycling groups, within the same denture liner material, the TBS in the PL group exhibited the highest and the ND group exhibited the lowest. Within the same denture base material, in both non-thermocycling and thermocycling groups, the TBS in the ST group exhibited the highest; in contrast, that in the GC group exhibited the lowest. No significant differences were observed in TBS between non-thermocycling and thermocycling groups, except for denture base materials bonded to the ST group, SC + UP, and ND + UP groups. Conclusions: Milled denture base can be relined with acrylic-based or silicone-based denture liner. However, cautions should be exercised when relining 3D printed denture base. Thermocycling did not affect TBS between acrylic-based denture liners and denture bases. In contrast, it affected the bond between silicone-based denture liner and denture base. [ABSTRACT FROM AUTHOR]

Background: Marginal misfit and surface roughness of customized implant abutments is critical for restorative success. However, little is known about the comparison of misfit and surface roughness of CAD-CAM Zirconium oxide (ZrO), selective laser melting (SLM) Cobalt Chrome (CoCr) and preformed abutments. The aim of the study is to investigate the relation of misfit and micro-roughness of selective laser melting (SLM), preformed and CAD-CAM implant abutments. Methods: Thirty internal connection, endosseous dental implants (Ø 4.0 mm x 10 mm, Dentium) were mounted in Polymethyl methacrylate vertically. Ten preformed Titanium alloy (Ti) abutments with 1 mm soft tissue height and Ø 4.5 mm were included as controls. Ten each of Y-TZP and SLM-CoCr, abutment/crowns were fabricated using CAD-CAM milling (CAD-CAM-ZrO) and SLM techniques. Surface micro-roughness (Ra) of the fabricated implant abutment/crown was evaluated with a 3D optical non-contact microscope. All implant restorations were torqued to implants (30 Ncm) using a Tohnichi BTGE digital torque gauge and were analyzed with Bruker micro-CT (Skyscan 1173) to detect micro-gaps at pre-selected points at implant abutment interface. The Ra and misfit data were compared using ANOVA, Tukey-Kramer, Kruskal-Wallis test and Pearson correlation (p < 0.05). Results: Mean Ra among SLM CoCr abutments [0.88 (0.09) µm] were lower than CAD-CAM-ZrO and higher than preformed Ti abutments. Horizontal misfit among SLM-CoCr [45.43 (9.41) µm] and preformed Ti [36.87 (13.23) µm] abutments was not statistically different (p > 0.05). Misfit was significantly higher in Y-TZP samples compared to SLM-CoCr (p = 0.031) and preformed Ti abutments (p = 0.01). Preformed Ti abutments showed significantly lower misfit compared to SLM-CoCr abutments (p = 0.01). A positive linear correlation was observed between the surface roughness (Ra) and vertical misfit (r = 0.61, p < 0.05). Conclusion: SLM CoCr abutments showed rough surface compared to preformed Ti abutments, while horizontal misfit was comparable among SLM-CoCr and preformed abutments. Misfit was significantly greater in Y-TZP abutments, compared to SLM and preformed abutments. SLM abutment fabrication technique needs further improvement to provide better fit and surface topography. [ABSTRACT FROM AUTHOR]

Background: While many denture base materials are currently available on the market, little data exists regarding their dimensional stability after exposure to the oral environment. This study aimed to evaluate the effect of thermocycling on the trueness and precision of milled, 3-dimensional (3D)-printed, and conventional digitally fabricated complete denture bases (CDBs). Methods: A completely edentulous maxillary stone model was scanned to generate a standard tessellation language (STL) file; this was imported into metal-milling-machine software (Redon Hybrid CAD-CAM metal milling machine, Redon, Turkey) to produce a metal model for fabricating 30 CDBs. These were divided into three groups (n = 10 in each) according to the construction technique: group 1, CAD-CAM milled CDBs; group 2, 3D-printed CDBs; and group 3, conventional compression molded CDBs. All CDBs were scanned after fabrication and evaluated before and after thermocycling using superimposition. The data were analyzed using a one-way ANOVA, Tukey's post hoc test, and a paired t-test. Results: The level of trueness between the CAD-CAM milled, 3D-printed, and compression molded CDBs showed significant differences before and after thermocycling (P < 0.05). Group 1 showed the highest degree of trueness before and after thermocycling, group 3 exhibited a higher degree of trueness than group 2 before thermocycling, and group 2 had a higher degree of trueness than group 3 after thermocycling. There was a significant difference in the precision for each CDB type before and after thermocycling (P < 0.05). Conclusion: The trueness of the CAD-CAM milling system in complete denture (CD) fabrication is superior to that of the 3D printing and conventional compression molding systems before and after thermocycling. Thermocycling had a significant effect on the precision of all CDB types. The compression molding system in CD construction is the most negatively affected via thermocycling with regard to the measures of trueness and precision. Clinical trial number: Not applicable, no human participants were involved. [ABSTRACT FROM AUTHOR]

Restorative material selection has become increasingly challenging due to the speed of new developments in the field of dental material science. The present narrative review gives an overview of the current indications for implant abutments and restoration materials for provisional and definitive implant‐supported fixed dental prostheses in partially edentulous patients. For single implant restorations, titanium base abutments for crowns are suggested as an alternative to the conventional stock‐ and customized abutments made out of metal or zirconia. They combine the mechanical stability of a metallic connection with the esthetic potential of ceramics. For multiple‐unit restorations, conical titanium bases especially designed for bridges are recommended, to compensate for deviating implant insertion axes and angulations. Even though titanium base abutments with different geometries and heights are available, certain clinical scenarios still benefit from customized titanium abutments. Indications for the definitive material in fixed implant restorations depend on the region of tooth replacement. In the posterior (not esthetically critical) zone, ceramics such as zirconia (3–5‐Ymol%) and lithium‐disilicate are recommended to be used in a monolithic fashion. In the anterior sector, ceramic restorations may be buccally micro‐veneered for an optimal esthetic appearance. Lithium‐disilicate is only recommended for single‐crowns, while zirconia (3–5‐Ymol%) is also recommended for multiple‐unit and cantilever restorations. Attention must be given to the specific mechanical properties of different types of zirconia, as some feature reduced mechanical strengths and are therefore not indicated for all regions and restoration span lengths. Metal‐ceramics remain an option, especially for cantilever restorations. [ABSTRACT FROM AUTHOR]

Purpose: This review aimed to summarize the evidence on patient‐reported outcomes and clinical performance of digitally fabricated removable partial dentures (RPDs) compared to traditionally fabricated dentures. Methods: Three databases were systematically searched (PubMed, CENTRAL, and Wiley online library) for clinical studies comparing digitally and conventionally fabricated RPDs regardless of data acquisition methods used for fabrication. The Cochrane Collaboration risk of bias assessment tool 2 and the Oxford Center for Evidence‐based Medicine tool were used to assess risk of bias, and level of evidence, respectively. Descriptive narrative analysis was used to summarize data on patient‐reported outcomes, as there were inadequate studies to pool data in a meta‐analysis. A random‐effects model was used to analyze the data of framework fit accuracy. Results: Ten randomized controlled trials were included in the systematic review, and 4 were included in the meta‐analysis. Two studies showed that digitally fabricated RPDs are associated with higher patient satisfaction than conventionally fabricated RPDs (with a mean difference of 12.5 mm on a 100‐satisfaction scale, p =.008). The pooled standardized mean difference for framework fit accuracy was 0.49 (p = 0.02) in favor of conventionally fabricated RPDs, which showed that conventionally fabricated RPDs have a quantitatively better fit compared to digitally fabricated RPDs. However, clinical evaluation studies showed that both frameworks have clinically acceptable fit. Conclusions: Current evidence shows that digitally fabricated RPDs are associated with higher patient satisfaction compared to conventionally fabricated RPDs. However, the scarcity of literature here warrants the generalization of this conclusion. Both digitally and conventionally fabricated metal RPD frameworks showed acceptable fit clinically. [ABSTRACT FROM AUTHOR]

Purpose: To compare the impact of three different chemical denture cleansers (CDCs) (Corega, chlorhexidine, and hydrogen peroxide) on the surface roughness, microhardness, and color stability of 3D‐printed, computer‐aided design and computer‐aided manufacturing (CAD‐CAM) milled, and heat‐polymerized denture base material (DBM). Materials and Methods: A total of 420 disc‐shaped specimens (10 ± 0.1 × 2 ±0.1 mm) were fabricated using three different construction techniques: three‐dimensional (3D) printing (n = 140), CAD‐CAM milling (n = 140), and heat‐polymerization (n = 140). Sixty specimens (20 of each DBM) were used for baseline (pre‐immersion) measurements (T1) for the tested surface properties (hardness [n = 10/material] and roughness [n = 10/material]). The remaining 360 specimens (n = 120/material) were investigated for surface roughness, microhardness, and color change after immersion for 1 year (T2) in distilled water or CDCs (n = 30/solution and n = 10/test). The data were analyzed using two‐way ANOVA, one‐way ANOVA followed by post‐hoc Tukey's test at a significance level of less than 0.05. Results: Significant differences were observed in the effects of the tested CDCs on the surface roughness, micro‐hardness, and color stability of varying DBM specimens (p < 0.05). Corega showed the highest surface roughness and color change in all DBMs while H2O2 resulted in the lowest microhardness for all DBMs. The lowest changes in all tested properties were seen with distilled water followed by chlorhexidine. A significant effect of type of cleanser, denture base material, and the interaction between the two was seen on all measured properties (p < 0.05). Conclusions: The tested CDCs significantly affected the surface properties of all DBMs but at varying degrees. Corega produced the highest negative effect on roughness and color change while H2O2 dramatically affected the microhardness. Prolonged use of CDCs should be cautiously followed. [ABSTRACT FROM AUTHOR]

Purpose: This in vitro study was conducted to compare the fracture resistance of tooth restoration complex restored with polyetheretherketone (PEEK) and lithium disilicate endocrowns. Materials and Methods: A total of 46 extracted premolars were collected and treated endodontically. The teeth were mounted in cylindrical molds using autopolymerizing resin and were prepared for endocrown restoration. Specimens were divided into two groups (n = 23) to receive endocrowns made with two different materials (polyetheretherketone and lithium disilicate). All the specimens were subjected to thermal cycling. The fracture resistance test was carried out using a Universal Testing Machine. Fractographic analysis was carried out using stereomicroscope and scanning electron microscope after load test. The values obtained were subjected to statistical analysis. Intergroup comparison (two groups) was performed using a t‐test. Comparison of frequencies of categories of variables with groups was performed using chi‐square test. Results: Fracture resistance tests showed a statistically significant difference in values between the two groups (p < 0.01). High fracture resistance values were seen with lithium disilicate endocrowns. Failure mode analysis showed that both groups exhibited mainly catastrophic failure. There were no significant differences in frequencies of the type of fracture between the groups. Conclusion: The fracture resistance of endocrowns fabricated with lithium disilicate material was found to be significantly higher than polyetheretherketone (PEEK) material. Hence, lithium disilicate material is superior for endocrowns. [ABSTRACT FROM AUTHOR]