Application of Chairside CAD/CAM and Its Influencing Factors among Chinese Dental Practitioners: a Crosssectional Study.

OBJECTIVE: To examine the increased use of chairside CAD/CAM among Chinese dental practitioners, and to explore the existing barriers influencing its further application and satisfaction levels. METHODS: A semi-structured questionnaire was developed to gather respondents' demographic information, as well as their experiences and behaviours regarding the implementation of chairside CAD/CAM. A specialised web-based survey system and WeChat were used to display and distribute the final questionnaire. Then, the data were analysed with Chi-square tests and regression analyses to determine the effects of various demographic variables on chairside CAD/ CAM applications. RESULTS: A total of 1,969 questionnaire responses were included in the analyses. Chairside CAD/ CAM systems were used by 36.9% of participants, with a higher usage rate observed among prosthodontists (60.0%) and dental practitioners holding a PhD degree (57.7%). Chairside CAD/ CAM-fabricated prostheses were most commonly used in the posterior maxilla (83.3%) and mandible (86.0%), followed by the anterior maxilla and mandible (63.8% and 48.6%, respectively). Major barriers to further application included high initial investment, frequent updates of equipment and software programs, and a lack of expertise in chairside CAD/CAM usage. CONCLUSION: Most dental practitioners did not use chairside CAD/CAM systems. The application rate was significantly influenced by sex, location, educational background, department and type of healthcare facility. Chairside CAD/CAM users showed limited satisfaction with the aesthetic performance of the fabricated prostheses. To improve the popularity of chairside CAD/CAM systems, especially among dental practitioners lacking advanced academic degrees, it is highly advisable to optimise CAD software programs and offer comprehensive training opportunities.

A randomised controlled trial comparing the effectiveness of guided bone regeneration with polytetrafluoroethylene titanium-reinforced membranes, CAD/CAM semi-occlusive titanium meshes and CAD/CAM occlusive titanium foils in partially atrophic arches.

PURPOSE: To compare the clinical effectiveness of three different devices used in guided bone regeneration procedures for partially atrophic arches. MATERIALS AND METHODS: A randomised controlled trial with three parallel arms was conducted. The study evaluated titanium-reinforced polytetrafluoroethylene membrane (PTFE group), semi-occlusive CAD/CAM titanium mesh (mesh group) and occlusive CAD/CAM titanium foil (foil group) in terms of surgical outcomes and complications as well as surgical times and surgeon satisfaction in 27 guided bone regeneration procedures, presenting results from 1 year post-implant placement. RESULTS: Complications occurred in seven patients. No significant difference was found between the groups in terms of the occurrence of complications (P = 0.51), device exposure (P = 0.12) and implant failure (P = 0.650). Surgeon satisfaction varied significantly, with the PTFE group differing from the mesh (P = 0.003) and foil groups (P 0.001), but not between meshes and foils (P = 0.172). Surgical times also differed significantly, with longer times for PTFE membranes compared to meshes (P 0.001) and foils (P = 0.006), but with no difference between meshes and foils (P = 0.308). The mean reconstructed bone volume was 1269.55 ± 561.08 mm3, with no significant difference observed between the three groups (P = 0.815). There was also no significant difference for mean maximum height (6.72 mm, P = 0.867) and width (7.69 mm, P = 0.998). The mean marginal bone loss at 1 year after implant placement was 0.59 ± 0.27 mm. CONCLUSIONS: Although this study provides valuable insights into the potential benefits of using different types of CAD/CAM devices, further research with larger sample sizes and longer follow-up periods is warranted to validate these findings. CONFLICT-OF-INTEREST STATEMENT: The authors declare there are no conflicts of interest relating to this study.

Internal fit and marginal adaptation of all-ceramic implant-supported hybrid abutment crowns with custom-milled screw-channels on Titanium-base: in-vitro study.

BACKGROUND: Advancements in digital dentistry helped in custom-milling screw-channels in implant-supported restorations; however, the fit of these restorations is still unclear especially for contemporary computer aided designing/computer aided manufacturing (CAD/CAM) materials. This study aimed to compare the internal and marginal fit of Ultra translucent multilayered zirconia versus lithium disilicate implant-supported hybrid abutment crowns (HACs) constructed with custom-milled screw-channels on Titanium-base. MATERIALS AND METHODS: A total of 24 HACs with custom-milled screw-channels were constructed from lithium disilicate (Group LDS) and Ultra translucent multilayered zirconia (Group UT) using digital workflow (n = 12). The internal and marginal gaps of HACs on their corresponding Titanium-bases were assessed using replica technique and stereomicroscope, respectively. After testing for normality, quantitative data were expressed as mean and standard deviation and compared using independent t-test at a level of significance (P ≤ 0.05). RESULTS: There was no statistically significant difference between Group LDS and Group UT in terms of marginal and internal fit. The internal and marginal gaps in both groups were within the accepted values reported in literature. CONCLUSIONS: UT and LDS HACs with custom-milled screw-channels demonstrated comparable and acceptable internal fit and marginal adaptations to Ti-base, which lied within the range reported in literature.

The effect of two preparation designs on the fracture resistance and marginal adaptation of two types of ceramic crowns using CAD/CAM technology (In vitro study).

BACKGROUND: Recently, prosthodontic approaches involve more conservative procedures that include less invasive finish line preparations that use less ceramic thickness. AIM OF THE STUDY: This in vitro study aimed to evaluate the effect of vertical preparation and modified vertical preparation designs on the marginal adaptation and fracture resistance of two types of ceramic crowns using CAD/CAM technology. MATERIALS AND METHODS: Two typodont maxillary first premolars were embedded in acrylic resin. Forty positive replicas of epoxy resin dies were used that were divided into two groups depending on the preparation design (n = 20); Group V (Vertical): dies with feather edge finish line and Group MV (Modified vertical): dies with feather edge finish line, where a reverse shoulder of 1 mm depth was placed on the buccal surface 1.5 mm from the occlusal surface. Each group was further subdivided into two subgroups according to the type of ceramic material (n = 10): Subgroup Va and subgroup MVa for lithium disilicate (e.max CAD) and subgroup Vb and subgroup MVb for zirconia (zolid ht+). Crown restorations were made with CAD-CAM technology. The marginal adaptation was assessed using a stereomicroscope both prior to cementation and after cementation and aging. Fracture resistance was tested with a universal testing machine, and the data were statistically analyzed. RESULTS: Marginal adaptation showed no significant differences between subgroups before or after cementation and aging. Three-way ANOVA indicated that preparation design (p = 0.516) and material (p = 0.269) had no significant effect, but cementation had a significant effect (p < 0.0001) on the marginal adaptation. According to two-way ANOVA test, Subgroup (MVb) showed the highest result followed by subgroup (Vb) and subgroub (MVa) and the least was subgroub (Va). Fracture modes showed no significant differences among the subgroups (p = 0.982). CONCLUSIONS: Marginal adaptation of lithium disilicate and zirconia crowns remained clinically acceptable regardless of preparation design. While the modified vertical preparation with a reverse shoulder notably enhanced the fracture resistance of both materials, with zirconia demonstrating superior fracture resistance compared to lithium disilicate with average values exceeding premolar biting force.

Evaluating the accuracy of CEREC intraoral scanners for inlay restorations: impact of adjacent tooth materials.

BACKGROUND: The accuracy of intraoral scanning is critical for computer-aided design/computer-aided manufacturing workflows in dentistry. However, data regarding the scanning accuracy of various adjacent restorative materials and intraoral scanners are lacking. This in vitro study aimed to evaluate the effect of adjacent restorative material type and CEREC's intraoral scanners on the accuracy of intraoral digital impressions for inlay cavities. METHODS: The artificial tooth was prepared with an occlusal cavity depth of 2 mm, a proximal box width at the gingival floor of 1.5 mm, and an equi-gingival margin extended disto-occlusally at the transition line angle on both the lingual and buccal sides for an inlay restoration. The adjacent teeth were veneered with crowns made of gold and zirconia, and an artificial tooth (resin) was utilized as the control group. The inlay cavity and adjacent teeth (Gold, Zirconia, and resin) were scanned 10 times using Chairside Economical Restoration of Esthetic Ceramics (CEREC) Primescan (PS), Omnicam (OC), and Bluecam (BC). A reference scan was obtained using a laboratory scanner (3-shape E3). Scanning was performed according to the manufacturer's instructions, including powder application for the BC group. Standard tesselation language files were analyzed using a three-dimensional analysis software program. Experimental data were analyzed using a two-way analysis of variance and the Tukey's post-hoc comparison test. RESULTS: The restorative materials of the adjacent teeth significantly affected the accuracy of the intraoral digital impressions (p < .05). The zirconia group exhibited the highest trueness deviation, followed by the resin and gold groups, with each demonstrating a statistically significant difference (p < .05). The resin group demonstrated the highest maximum positive deviation and deviation in precision. Gold exhibited the lowest average deviation value for trueness compared with those of the other adjacent restorative materials. Intraoral scanner type significantly influenced the trueness and precision of the scan data (p < .05). The average deviation of trueness according to the intraoral scanner type increased in the following order: BC > PS > OC. The average deviation in precision increased in the following order: PS>OC>BC (p < .05). CONCLUSION: The restorative materials of the adjacent tooth and the type of intraoral scanner affect the accuracy of the intraoral digital impression. The trueness of the digital images of the BC group, obtained by spraying the powder, was comparable to that of the PS group. Among the adjacent restorative materials, zirconia exhibited the lowest trueness. In contrast, PS demonstrated the highest precision among the intraoral scanners, while resin displayed the lowest precision among the adjacent restorative materials.

Optimization of three-dimensional printing parameters for orthodontic applications.

OBJECTIVES: To determine the impact of build orientation, increased layer thickness, and dental crowding on the trueness of three-dimensional (3D)-printed models, and to evaluate how these parameters affect the fit of thermoformed appliances. MATERIALS AND METHODS: Ninety-six dental models were printed horizontally and vertically on the building platform using different 3D-printing technologies: (1) a stereolithography (SLA) printer with layer thicknesses of 160 µm and 300 µm and (2) a digital light processing (DLP) printer with layer thicknesses of 100 µm and 200 µm. Each printed model was digitalized and superimposed on the corresponding source file using 3D rendering software, and deviations were quantified by the root mean square values. Subsequently, a total of 32 thermoformed appliances were fabricated on top of the most accurate 3D-printed models, and their fit was evaluated by digital superimposition and inspection by three blinded orthodontists. Paired t-tests were used to analyze the data. RESULTS: Significant differences (P < .05) between printing technologies used were identified for models printed horizontally, with the SLA system achieving better trueness, especially in crowded dentitions. No significant differences between technology were found when models were printed vertically. The highest values of deviation were recorded in appliances fabricated on top of DLP-printed models. The results of the qualitative evaluation indicated that appliances fabricated on top of SLA models outperformed the DLP-modeled appliances. CONCLUSIONS: Three-dimensional printing with increased layer height seems to produce accurate working models for orthodontic applications.

Digital Platform Facilitates Successful Facially Driven Orthodontic-Restorative Treatment.

This case report presents a novel digital technique for prosthetically driven orthodontic treatment. A 28-year-old patient who had undergone orthodontics as a teenager experienced a relapse and presented with esthetic concerns. The author utilized state-of-the-art software to create a virtual orthodontic-restorative treatment outcome with virtual restorations. This approach helped guide tooth movement, improve team communication, and optimize treatment outcomes while allowing for minimally invasive restorative treatment.

The wettability of complete denture base materials constructed by conventional versus digital techniques: an in-vitro study.

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.

Prosthodontic rehabilitation with all-on-four implant treatment combined CAD/CAM prosthesis in an oral cancer patient: a case report.

BACKGROUND: The microvascular free fibula (MFF) flap is a reliable treatment modality for mandibular reconstruction and is suitable for dental implant placement after oncologic surgery. The most common issue with the MFF flap is its limited bone height, which typically results in excessive interarch space and complicates prosthodontic therapy. Overcoming the physical limitations from tumor excision and reducing the treatment time for prosthodontic rehabilitation to improve quality of life are critical clinical challenges. CASE PRESENTATION: A 64-year-old male with lower left gum and bilateral buccal cancer received a single-layer microvascular MFF flap to reconstruct a mandibular defect post-tumor excision. He underwent a bilateral modiolus Z-plasty combined with a skin flap debulking procedure to relieve oral contracture, achieving adequate mouth opening for prosthodontic rehabilitation. Scar tissue bands on the bilateral cheeks significantly affected retention and stability, hampering dental impression performance. The patient sought prosthodontic rehabilitation to enhance his chewing function and quality of life promptly. Prosthodontic rehabilitation with all-on-4 implant therapy, utilizing computer-aided design and computer-assisted manufacturing (CAD/CAM), was completed within one month. CONCLUSION: This case utilized the all-on-4 implant system to address the insufficient fibular height for conventional dental implant placements. Dental CAD/CAM was employed to mill custom prosthetic abutments and a large titanium framework for the implant bar overdenture, compensating for the excessive interarch space between the grafted fibula and maxilla. This treatment approach successfully shortened the prosthodontic rehabilitation time and overcame anatomical limitations.

Digital planning in joint orthodontic-restorative care.

Combined orthodontic-restorative treatment represents an increasing proportion of our practice, mirroring increasing provision of adult orthodontics and refinements in appliance design. By harnessing simple digital technology, it may be possible to promote more predictable aesthetic, biological and functional interdisciplinary outcomes. In particular, digital approaches can be embedded in the diagnostic and treatment planning phase, enhancing our communication with patients and colleagues while also permitting more detailed analysis and more refined planning.

A severely damaged premolar tooth restored with coronal pulpotomy and a 3D-printed endocrown.

Advances in computer-aided design/computer-aided manufacturing (CAD-CAM) technologies and adhesives have enabled the use of endocrowns as an effective and conservative treatment option for restoring endodontically treated teeth in pediatric populations. Thus, this case report presents the treatment of a severely damaged premolar tooth with coronal pulpotomy and a 3D-printed endocrown restoration. A 13-year-old patient with pain due to profound caries in the left maxillary second premolar tooth was referred to the Department of Pediatric Dentistry at Gazi University in Ankara, Türkiye. Deep dentinal caries and severe tissue loss were revealed in the clinical examination. No periradicular lesions were detected in a radiographic examination, and there was no inflammation in the pulp. The selected intervention was a two-step process involving a coronal pulpotomy followed by a custom 3D-printed endocrown restoration. No clinical complications or radiographic pathologies were observed over a two-year follow-up period, and the patient was satisfied with the final esthetics and function of the restoration. 3D-printing technology can be successfully integrated into pediatric restorative dentistry and offers a conservative, efficient, and esthetically pleasing treatment option for children with severely damaged dentition.

Reinforcement learning-driven exploration of peptide space: accelerating generation of drug-like peptides.

Using amino acid residues in peptide generation has solved several key problems, including precise control of amino acid sequence order, customized peptides for property modification, and large-scale peptide synthesis. Proteins contain unknown amino acid residues. Extracting them for the synthesis of drug-like peptides can create novel structures with unique properties, driving drug development. Computer-aided design of novel peptide drug molecules can solve the high-cost and low-efficiency problems in the traditional drug discovery process. Previous studies faced limitations in enhancing the bioactivity and drug-likeness of polypeptide drugs due to less emphasis on the connection relationships in amino acid structures. Thus, we proposed a reinforcement learning-driven generation model based on graph attention mechanisms for peptide generation. By harnessing the advantages of graph attention mechanisms, this model effectively captured the connectivity structures between amino acid residues in peptides. Simultaneously, leveraging reinforcement learning's strength in guiding optimal sequence searches provided a novel approach to peptide design and optimization. This model introduces an actor-critic framework with real-time feedback loops to achieve dynamic balance between attributes, which can customize the generation of multiple peptides for specific targets and enhance the affinity between peptides and targets. Experimental results demonstrate that the generated drug-like peptides meet specified absorption, distribution, metabolism, excretion, and toxicity properties and bioactivity with a success rate of over 90$\%$, thereby significantly accelerating the process of drug-like peptide generation.

Fracture strength of cad-cam milled polyetheretherketone (PEEK) post-cores vs conventional post-cores; an in vitro study.

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.

Structure-Aided Computational Design of Triazole-Based Targeted Covalent Inhibitors of Cruzipain.

Cruzipain (CZP), the major cysteine protease present in T. cruzi, the ethiological agent of Chagas disease, has attracted particular attention as a therapeutic target for the development of targeted covalent inhibitors (TCI). The vast chemical space associated with the enormous molecular diversity feasible to explore by means of modern synthetic approaches allows the design of CZP inhibitors capable of exhibiting not only an efficient enzyme inhibition but also an adequate translation to anti-T. cruzi activity. In this work, a computer-aided design strategy was developed to combinatorially construct and screen large libraries of 1,4-disubstituted 1,2,3-triazole analogues, further identifying a selected set of candidates for advancement towards synthetic and biological activity evaluation stages. In this way, a virtual molecular library comprising more than 75 thousand diverse and synthetically feasible analogues was studied by means of molecular docking and molecular dynamic simulations in the search of potential TCI of CZP, guiding the synthetic efforts towards a subset of 48 candidates. These were synthesized by applying a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) centered synthetic scheme, resulting in moderate to good yields and leading to the identification of 12 hits selectively inhibiting CZP activity with IC50 in the low micromolar range. Furthermore, four triazole derivatives showed good anti-T. cruzi inhibition when studied at 50 µM; and Ald-6 excelled for its high antitrypanocidal activity and low cytotoxicity, exhibiting complete in vitro biological activity translation from CZP to T. cruzi. Overall, not only Ald-6 merits further advancement to preclinical in vivo studies, but these findings also shed light on a valuable chemical space where molecular diversity might be explored in the search for efficient triazole-based antichagasic agents.

ANALYSIS OF THE USE OF COMPLEX DIGITAL TECHNOLOGIES IN THE DIAGNOSIS AND TREATMENT OF OCCLUSAL ANOMALIES.

BACKGROUND: Digital technologies have expanded in the field of dentistry, especially in the clinical and diagnostic aspects of occlusal abnormalities. Consequently, the purpose of this narrative review is to identify and synthesize data concerning the effects of these sophisticated digital technologies on improved diagnostic performance, treatment interventions, and patient outcomes. METHODS: Cochrane, Scopus, Web of Science, and PubMed were searched and, therefore, performed to find the pertinent digital technologies in dentistry from the published literature. The search was conducted in the period between 2000 and 2024. The criteria for inclusion of the studies targeted technologies that were Cone-Beam Computed Tomography (CBCT), intraoral scanners, 3D imaging, and Computer-Aided Design and Manufacturing (CAD/CAM). Some of the comparing between conventional and modern approaches were raised. RESULTS: Digital technologies have enhanced the diagnostic process due to extended visualization and precise evaluation of occlusal disturbances Conclusion: It has been seen that the application of information technologies in dentistry significantly improved the diagnostics and therapy of occlusion disturbances. While there are some invincible challenges posed by these advancements, the prospects are noteworthy when it comes to accuracy, efficiency, and patient benefits.

Computer-Aided Drug Design Using the Fragment Molecular Orbital Method: Current Status and Future Applications for SBDD.

Owing to the increasing use of computers, computer-aided drug design (CADD) has become an essential component of drug discovery research. In structure-based drug design (SBDD), including inhibitor design and in silico screening of drug target molecules, concordance with wet experimental data is important to provide insights on unique perspectives derived from calculations. Fragment molecular orbital (FMO) method is a quantum chemical method that facilitates precise energy calculations. Fragmentation method makes it possible to apply the quantum chemical method to biological macromolecules for energy calculation based on the electron behavior. Furthermore, interaction energies calculated on a residue-by-residue basis via fragmentation aid in the analysis of interactions between the target and ligand molecule residues and molecular design. In this review, we outline the recent developments in SBDD and FMO methods and highlight the prospects of developing machine learning approaches for large computational data using the FMO method.

Do intraoral scanning technologies affect the trueness of dental arches with crowding, diastema, and edentulous spaces? A clinical perspective.

OBJECTIVES: To evaluate the trueness of dental arches digitised by two intraoral scanning (IOS) technologies from patients presenting crowding, diastema, and bilateral posterior edentulous space with tilted molar. METHODS: Conventional impressions and dental stone models were generated from three patients presenting the aforementioned dental arch conditions. These models were digitised on a desktop scanner, and the resulting mesh was used as reference. Subsequently, the patients were scanned using confocal based (CF; iTero Element 2) and blue laser-multiscan (BLM; Virtuo Vivo) imaging IOS technology, totalling thirty scans. The meshes from the scans were exported in Standard Tessellation Language format and analysed using Geomagic Control X software. Root mean square (RMS) indicated deviation magnitude. Differences in IOS technologies were evaluated with paired t-tests, and dental arch conditions compared using ANOVA and post-hoc Tukey tests (α=0.05). RESULTS: Digital dental arch from blue laser-multiscan technology showed lower trueness compared to confocal based technology for crowding (p = 0.0084) and edentulous spaces (p = 0.0025) conditions. When the types of oral condition were compared, discrepancies were significantly different for both IOS technologies, featuring the arch with diastema showing the lowest trueness, followed by edentulous spaces and crowding. CONCLUSION: Dental arches presenting crowding and edentulous spaces digitised by blue laser-multiscan technology exhibited greater discrepancies compared to confocal based imaging technology. Furthermore, trueness varied among the dental arch conditions. CLINICAL SIGNIFICANCE: The IOS technology and patient's dental arch condition can influence the trueness of dental arch digitisation. Being aware of these effects allows clinicians to take them into account during scanning procedures, digital planning and manufacturing.

In vitro comparison of guide planes for removable partial dentures prepared with CAD-CAM-assisted templates, guiding rod templates, and freehand.

OBJECTIVES: This study aimed to evaluate the accuracy of computer-aided design and computer-aided manufacturing (CAD-CAM)-assisted templates (CCAT), guiding rod templates (GRT), and freehand (FH) preparation of guide planes. METHODS: Forty-five identical maxillary resin casts were divided into three groups, in which the guide planes of the two abutment teeth were prepared using a CCAT (n=15), GRT (n=15), and FH (n=15). The CCAT and GRT were digitally designed on a digital cast of virtually prepared guide planes and fabricated using three-dimensional printing (3DP) technology. To assess the 3D trueness, the prepared guide planes were digitally scanned and compared to the virtually designed guide planes. The angle deviation was measured to assess the trueness of the direction of the guide plane preparation. Shapiro-Wilk and Levene's tests were used to check the normality and equivalence of the variance of the data. The data were compared by using the Kruskal‒Wallis H test (α=0.05). RESULTS: The CCAT group exhibited significantly better 3D trueness (78.5±19.8 µm) than the GRT group (211.3±42.4 µm, p<0.05) and the FH group (198.9±44.3 µm, p<0.05). Additionally, the CCAT group (1.31±0.50°) showed significantly smaller direction trueness compared to the GRT (4.65±0.72°, p<0.05) and FH (5.64±0.70°, p<0.05) groups. CONCLUSIONS: The novel CAD-CAM-assisted template significantly improved the quality of the guide planes compared with the GRT and FH procedures. This enhancement suggests that removable partial dentures can be predictably inserted immediately after guide plane preparation. CLINICAL SIGNIFICANCE: CAD-CAM-assisted templates improve the quality of guide plane preparation.

Comparison of misfit and roughness of CAD-CAM ZrO, selective laser sintered CoCr and preformed Ti implant abutment crowns.

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.

Systematic computer-aided disulfide design as a general strategy to stabilize prefusion class I fusion proteins.

Numerous enveloped viruses, such as coronaviruses, influenza, and respiratory syncytial virus (RSV), utilize class I fusion proteins for cell entry. During this process, the proteins transition from a prefusion to a postfusion state, undergoing substantial and irreversible conformational changes. The prefusion conformation has repeatedly shown significant potential in vaccine development. However, the instability of this state poses challenges for its practical application in vaccines. While non-native disulfides have been effective in maintaining the prefusion structure, identifying stabilizing disulfide bonds remains an intricate task. Here, we present a general computational approach to systematically identify prefusion-stabilizing disulfides. Our method assesses the geometric constraints of disulfide bonds and introduces a ranking system to estimate their potential in stabilizing the prefusion conformation. We hypothesized that disulfides restricting the initial stages of the conformational switch could offer higher stability to the prefusion state than those preventing unfolding at a later stage. The implementation of our algorithm on the RSV F protein led to the discovery of prefusion-stabilizing disulfides that supported our hypothesis. Furthermore, the evaluation of our top design as a vaccine candidate in a cotton rat model demonstrated robust protection against RSV infection, highlighting the potential of our approach for vaccine development.