Creation and evaluation of an educational escape room for preclinical training on 3D printing in dentistry.

INTRODUCTION: The benefit of pedagogical escape rooms for dental students' stimulation, interest and knowledge strengthening has been suggested by several studies. However, in previous studies, only a few students were evaluated. This study aims to confirm the purpose of this innovative pedagogical tool in terms of learning consolidation and team building from students' perceptions. We directly incorporated an educational escape game into the fundamental academic formation as a practical-work course for fifth-year dental students. MATERIALS AND METHODS: The present escape game focused on 3D printing, whose implementation fit the different steps of an escape game well. This study was conducted in March 2022. All fifth-year dental students (n = 212) were divided into 5-6 student groups to match the conditions of an escape game. Before entering the room, each student had to complete a cross-sectional knowledge true/false test of 8 questions to assess their general level. Additionally, an 18-question appreciation survey was completed when leaving the room. RESULTS: The students perceived the 3D-printing escape game to be relevant and especially expressed the benefit of being part of a team to exchange and build knowledge. These results suggest knowledge strengthening. The instructional benefit of this process seemed to exceed its mere fun and appealing aspect. CONCLUSION: Our results with a large number of students showed that, from the students' perception, the educational escape game significantly improved knowledge and team-building. It created a supportive learning environment and increased students' motivation. It can provide a fun and effective way to diversify instruction.

Degree of conversion of 3D printing resins used for splints and orthodontic appliances under different postpolymerization conditions.

OBJECTIVES: To measure the degree of conversion (DC) of different 3D printing resins used for splints or orthodontic appliances under different postpolymerization conditions. MATERIALS AND METHODS: Five 3D-printed photopolymer resins were studied. Each resin was analyzed in liquid form (n = 15), and then cylindrical specimens (n = 135) were additively manufactured and postcured with Form Cure (Formlabs) at different times (10, 60, and 90 min) and temperatures (20 °C, 60 °C, and 80 °C). The DC of each specimen was measured with Fourier transform infrared spectroscopy (FTIR). The data were statistically analyzed using a 3-way ANOVA followed by Tukey's post hoc test. RESULTS: The time and temperature of postpolymerization significantly influenced the DC of each resin: when time and/or temperature increased, the DC increased. For all resins tested, the lowest DC was obtained with a postcuring protocol at 10 min and 20 °C, and the highest DC was obtained at 90 min and 80 °C. However, at 80 °C, the samples showed a yellowish color. CONCLUSIONS: With the Form Cure device, the time and temperature of postcuring could have an impact on the DC of the 3D printing resins studied. The DC of the 3D printing resins could be optimized by adjusting the postpolymerization protocol. CLINICAL RELEVANCE: Regardless of the resin used, when using the Form Cure device, postcuring at 60 min and 60 °C would be the minimal time and temperature conditions for achieving proper polymerization. Beyond that, it would be preferable to increase the postcuring time to boost the DC.

Hindlimb Somatosensory Information Influences Trunk Sensory and Motor Cortices to Support Trunk Stabilization.

Sensorimotor integration in the trunk system is poorly understood despite its importance for functional recovery after neurological injury. To address this, a series of mapping studies were performed in the rat. First, the receptive fields (RFs) of cells recorded from thoracic dorsal root ganglia were identified. Second, the RFs of cells recorded from trunk primary sensory cortex (S1) were used to assess the extent and internal organization of trunk S1. Finally, the trunk motor cortex (M1) was mapped using intracortical microstimulation to assess coactivation of trunk muscles with hindlimb and forelimb muscles, and integration with S1. Projections from trunk S1 to trunk M1 were not anatomically organized, with relatively weak sensorimotor integration between trunk S1 and M1 compared to extensive integration between hindlimb S1/M1 and trunk M1. Assessment of response latency and anatomical tracing suggest that trunk M1 is abundantly guided by hindlimb somatosensory information that is derived primarily from the thalamus. Finally, neural recordings from awake animals during unexpected postural perturbations support sensorimotor integration between hindlimb S1 and trunk M1, providing insight into the role of the trunk system in postural control that is useful when studying recovery after injury.

Cohesin association to replication sites depends on rad50 and promotes fork restart.

The cohesin complex holds together newly replicated chromatids and is involved in diverse pathways that preserve genome integrity. We show that in budding yeast, cohesin is transiently recruited to active replication origins, and it spreads along DNA as forks progress. When DNA synthesis is impeded, cohesin accumulates at replication sites and is critical for the recovery of stalled forks. Cohesin enrichment at replication forks does not depend on γH2A(X) formation, which differs from its loading requirements at DNA double-strand breaks (DSBs). However, cohesin localization is largely reduced in rad50Δ mutants and in cells lacking both Mec1 and Tel1 checkpoint kinases. Interestingly, cohesin loading at replication sites depends on the structural features of Rad50 that are important for bridging sister chromatids, including the CXXC hook domain and the length of the coiled-coil extensions. Together, these data reveal a function for cohesin in the maintenance of genome integrity during S phase.

Shear bond strength and interface analysis between a resin composite and a recent high-viscous glass ionomer cement bonded with various adhesive systems.

OBJECTIVE: This study investigated the shear bond strength (SBS) and interface between a resin composite and a new high-viscous glass ionomer cement (HV-GIC), a HV-GIC, a resin-modified glass ionomer cement (RM-GIC), a bulk-fill flowable composite, and a regular flowable composite bonded with various adhesive systems. METHODS AND MATERIALS: A resin composite (Filtek Z350) was bonded to a new HV-GIC (EQUIA Forte Fil) using various adhesive systems, including a universal adhesive in self-etch and etch-and-rinse mode (Scotchbond Universal), a two-step etch-and-rinse adhesive (Scotchbond 1-XT), a one-step self-etch adhesive (Optibond All-in-one) tested also after silane application (Monobond Plus), and a coating material (EQUIA Forte Coat). The resin composite was also bonded to a HV-GIC (Fuji IX GP), a RM-GIC (Fuji II LC), a bulk-fill flowable composite (SDR), and a regular flowable composite (Tetric Evo Flow) with the universal adhesive in self-etch mode (Scotchbond Universal). Two-way ANOVA followed by Dunnett's post hoc test was used to investigate the difference in SBS. Failures were analyzed by chi-square test. Bonding interfaces were examined by environmental scanning electron microscopy (E-SEM). RESULTS: SBS to EQUIA Forte Fil was significantly lower with Scotchbond 1-XT than with all other adhesive systems. By using Scotchbond Universal with the self-etch technique, the SBS to EQUIA Forte Fil was significantly higher than the SBS to Fuji IX GP and significantly lower than the SBS to Fuji II LC, SDR, and Tetric Evo Flow. E-SEM images showed an intimate contact at all interfaces examined. CONCLUSION: EQUIA Forte Fil showed satisfactory SBS and interfaces with all adhesives tested. CLINICAL RELEVANCE: Bonding between the resin composite and HV-GIC can be achieved using a universal adhesive in self-etch mode, an easy-to-use adhesive system.

The banana (Musa acuminata) genome and the evolution of monocotyledonous plants.

Bananas (Musa spp.), including dessert and cooking types, are giant perennial monocotyledonous herbs of the order Zingiberales, a sister group to the well-studied Poales, which include cereals. Bananas are vital for food security in many tropical and subtropical countries and the most popular fruit in industrialized countries. The Musa domestication process started some 7,000 years ago in Southeast Asia. It involved hybridizations between diverse species and subspecies, fostered by human migrations, and selection of diploid and triploid seedless, parthenocarpic hybrids thereafter widely dispersed by vegetative propagation. Half of the current production relies on somaclones derived from a single triploid genotype (Cavendish). Pests and diseases have gradually become adapted, representing an imminent danger for global banana production. Here we describe the draft sequence of the 523-megabase genome of a Musa acuminata doubled-haploid genotype, providing a crucial stepping-stone for genetic improvement of banana. We detected three rounds of whole-genome duplications in the Musa lineage, independently of those previously described in the Poales lineage and the one we detected in the Arecales lineage. This first monocotyledon high-continuity whole-genome sequence reported outside Poales represents an essential bridge for comparative genome analysis in plants. As such, it clarifies commelinid-monocotyledon phylogenetic relationships, reveals Poaceae-specific features and has led to the discovery of conserved non-coding sequences predating monocotyledon-eudicotyledon divergence.

Shear bond strength of a RMGIC for orthodontic bracket bonding to enamel.

OBJECTIVE: To evaluate the shear bond strength (SBS) of a restorative resin-modified glass ionomer cement (RMGIC) for orthodontic bracket bonding. MATERIALS AND METHODS: One hundred twenty-one human teeth were randomly divided into 11 groups (n = 11) according to the surface treatment applied (H3PO4 ± Transbond Plus (TSEP) or Scotchbond Universal (SU)), and the adhesive used (Riva LC HV (RIVA), Fuji Ortho (FUJI), and Transbond XT (TXT)). For each sample, a metal button was bonded. SBS tests were performed at 1 week and debonded specimens were observed for failure modes determination. One-way ANOVA followed by Tukey's post hoc test was used to compare SBS differences and Fisher's exact test to analyze the failure modes (p < 0.05). RESULTS: TSEP + FUJI and H3PO4 + SU + TXT showed the highest SBS values while H3PO4 + TSEP + RIVA showed the lowest value. Cohesive failure and mixed failure were found in the groups with SU and TXT and adhesive failure in the other groups. DISCUSSION/CONCLUSIONS: The bonding of orthodontic attachments to enamel could be performed with any of the three materials studied. The use of a universal adhesive in the bonding protocol could optimize the adhesion values. Clinical studies would be needed to confirm the results obtained.

Touch-cure activation by marketed universal resin luting cements of their associated primer to dentin.

PURPOSE: The aim of this study was to investigate the dentin shear bond strength (SBS) and bonding interface of three recently developed "universal" resin luting cements based on different modalities. METHODS: The dentin SBS and interfacial analysis of three recently launched "universal" resin luting cements, namely, G-Cem One, RelyX Universal and Panavia SA cement universal, were studied. All bonding protocols, including the previous use of their dedicated primer or universal adhesive in touch-cure mode or light-cure mode were performed. Variolink Esthetic LC used in conjunction with Scotchbond Universal Plus was used as a control group. For each group (n = 9), 10 specimens were tested for dentin SBS and two were examined by scanning electron microscopy. SBS were analyzed by two-way ANOVA followed by Dunnett's test. RESULTS: SBS values showed that the three "universal" resin luting cements tested exhibit different adhesive behaviors. G-Cem One with its touch-cure activated primer had a greater SBS to dentin (25.5 MPa) than that of the control group (22.1 MPa). CONCLUSION: "Universal" resin luting cements have variable efficacy when used in self-curing mode. The touch-curing mode is also of concern but may show high potential for some formulations.

In vitro remineralization by various ion-releasing materials of artificially demineralized dentin: A micro-CT study.

OBJECTIVE: The aim of this study was to evaluate the remineralizing properties of ion-releasing restorative materials on pH cycling-induced carious dentin. METHODS: Fifty sound molars were freshly extracted. The occlusal surfaces were abraded using water-cooled sandpaper (800 grit). The residual crowns were embedded in self-cured acrylic resin with the flat dentin surface exposed. A mesio-distal trench was created using a calibrated 0.5 mm deep occlusal reduction burr, and artificial dentin caries were generated by pH cycling. Then, teeth were randomly assigned to five groups according to the ion-releasing material used. For each sample, micro-CT acquisitions were performed at various intervals. Remineralization was assessed by mean gray value (MGV) measurements after registration and segmentation of the region of interest with 3D Slicer software. One-way repeated-measures ANOVA followed by Tukey's post hoc test was used to investigate the difference in MGVs among the various groups. RESULTS: Only Cention Forte showed significantly increased MGVs after 4 weeks compared to demineralized dentin. MGVs were higher, but not significantly, after placement of the restorative materials, including in the resin composite control group. These results can be explained by the radiopacity of the materials. SIGNIFICANCE: Cention Forte, the material with the highest radiopacity, showed a significant increase in the MGVs of artificially carious dentin after 4 weeks. However, the study of dentin remineralization by micro-CT could be impacted by the radiopacity of the restorative materials used. The relevance of this examination for the study of dentinal remineralization should be investigated.

Interdisciplinary full mouth rehabilitation of a patient with amelogenesis imperfecta from childhood to young adult-hood: A 12-year case report.

Treatment of patients with amelogenesis imperfecta extends over many years, from childhood to early adulthood. Their management at any age is complex and has to be adapted in relation to therapies validated in the general population.

Vat Photopolymerization 3D Printing in Dentistry: A Comprehensive Review of Actual Popular Technologies.

In this comprehensive review, the current state of the art and recent advances in 3D printing in dentistry are explored. This article provides an overview of the fundamental principles of 3D printing with a focus on vat photopolymerization (VP), the most commonly used technological principle in dental practice, which includes SLA, DLP, and LCD (or mSLA) technologies. The advantages, disadvantages, and shortcomings of these technologies are also discussed. This article delves into the key stages of the dental 3D printing process, from computer-aided design (CAD) to postprocessing, emphasizing the importance of postrinsing and postcuring to ensure the biocompatibility of custom-made medical devices. Legal considerations and regulatory obligations related to the production of custom medical devices through 3D printing are also addressed. This article serves as a valuable resource for dental practitioners, researchers, and health care professionals interested in applying this innovative technology in clinical practice.

Perceptions regarding the use of a three-dimensionally-printed manufactured educational simulator for periodontal treatment of intraosseous and interradicular lesions.

PURPOSE/OBJECTIVES: Treating intraosseous lesions (IOLs) and interradicular bone lesions (IRLs) is an extremely technical dental procedure in periodontics. Instrumentation of these lesions is often perceived as difficult by students and inexperienced dentists before they perform a certain number of procedures on patients in the clinic. The aim of this article is to evaluate a cost-effective three-dimensional (3D)-printed educational simulator for the periodontal treatment of IOLs/IRLs (including scaling, incisions and sutures). METHODS: The simulators were first developed digitally, and then manufactured using printable resins and specific materials; finally, they were assembled using different bonding systems. To evaluate the simulators, assessments were gathered from two target populations: undergraduate students and periodontics experts. These individuals tested the simulator and completed a cross-sectional questionnaire based on a Likert scale with comparative and pedagogical items scored from one to five. The purpose of the questionnaire was to compare our simulator to clinical reality (i.e., operation on human jaws) and to an animal simulator (i.e., simulation of porcine jaws). The results are expressed as the mean and standard deviation and were statistically analyzed with the Wilcoxon signed-rank test. RESULTS: Overall, the results were satisfactory for both groups of testers (4.70 and 4.61 out of five for students and experts, respectively, for global satisfaction). CONCLUSIONS: The overall educational relevance of the simulator designed herein highlights the fact that 3D-printed educational simulators could enable efficient cognitive-functional learning for clinical IOL/IRL treatment.

Analysis of Resin-Based Dental Materials' Composition Depending on Their Clinical Applications.

The objective of this study was to detail the monomer composition of resin-based dental materials sold in the market in 2023 and to evaluate the proportion of bisphenol A (BPA)-derivatives in relation to their applications. A search on manufacturers' websites was performed to reference resin-based dental materials currently on the European market (including the European Union (EU) and United Kingdom (UK). Their monomer composition was determined using material-safety data sheets and was completed by a search on the PubMed database. Among the 543 material compositions exploitable, 382 (70.3%) contained BPA derivatives. Among them, 56.2% contained BisGMA and 28% BisEMA, the most frequently reported. A total of 59 monomers, of which six were BPA derivatives, were found. In total, 309 materials (56.9%) contained UDMA and 292 (53.8%) TEGDMA. Less than one third of materials identified contained no BPA derivatives. These proportions vary a lot depending on their applications, with materials dedicated to the dental care of young populations containing the highest proportions of BPA-derivative monomers. The long-term effects on human health of the different monomers identified including BPA-derivative monomers is a source of concern. For children and pregnant or lactating women arises the question of whether to take a precautionary principle and avoid the use of resin-based dental materials likely to release BPA by opting for alternative materials.

The Reinforced Treat-and-Extend Protocol for Exudative Age-Related Macular Degeneration: Retrospective Assessment of 24-Month Real-World Outcomes in France.

INTRODUCTION: The aim of this work is to evaluate the real-world outcomes of the reinforced treat-and-extend (RTE) protocol for the treatment of exudative age-related macular degeneration with intravitreal injections of aflibercept or ranibizumab (anti-vascular endothelial growth factor therapies). METHODS: This was a retrospective review of patients from two tertiary ophthalmology centers in France initiating the RTE protocol between February 2018 and June 2021. The primary outcome was change in best-corrected visual acuity (BCVA) after 24 months. Secondary outcomes were change in central retinal thickness (CRT), recurrence, and management-related factors (injection interval, number of injections/consultations). Outcomes were additionally evaluated after protocol changes (strict versus modified RTE protocol groups). RESULTS: Sixty-eight patients (72 eyes) were included (68% females; mean age 82.2 ± 7.8 years). After 24 months, mean BCVA significantly improved (65.22 ± 14 vs. 71.96 ± 13 Early Treatment Diabetic Retinopathy Study letters; p < 0.001) and CRT significantly decreased (388.6 ± 104 vs. 278.8 ± 51 µM; p < 0.001) with 21% of eyes showing signs of exudation. Over the 24 months, a mean total of 14.9 ± 4.0 injections and 8.6 ± 1.4 consultations were performed. Mean 24-month injection interval was 7.9 ± 2.3 weeks. Initial and 24-month ophthalmic outcomes for eyes in the strict (47%) versus modified (53%) groups were not significantly different, but mean time interval to first recurrence of disease activity was significantly shorter for the modified group (7.3 ± 2.4 vs. 9.9 ± 2.5 weeks; p < 0.001). Patients in the strict RTE group received significantly less injections (13.9 ± 3.6 vs. 16.5 ± 3.9; p = 0.006) and mean 24-month injection interval was significantly longer (9.5 ± 2.7 vs. 6.5 ± 2.1 weeks; p < 0.001). Consultation number was similar (8.5 ± 1.9 vs. 8.8 ± 1.6; p = 0.93). Treatment with aflibercept versus ranibizumab did not influence ophthalmic or management outcomes. CONCLUSIONS: The RTE protocol, even when modified, reduced consultations but improved ophthalmic outcomes. The RTE protocol could reduce hospital visits and overall burden while also encouraging better patient compliance. Video Abstract available for this article. VIDEO ABSTRACT: Vincent Soler and François-Philippe Roubelat summarize the Reinforced Treat-and-Extend Protocol and main results (MP4 225022 KB).

In vitro shear bond strength over zirconia and titanium alloy and degree of conversion of extraoral compared to intraoral self-adhesive resin cements.

OBJECTIVE: Evaluation of the Shear bond strength over zirconia and titanium alloy and degree of conversion of extraoral compared to intraoral self-adhesive resin cements. MATERIALS AND METHODS: Nine bonding protocols were carried out on zirconia 4Y-TZP and titanium alloy (Ti-6Al-4V). Seven resin cement (one extraoral and six intraoral) were tested in the shear bond strength test and the degree of conversion measurements. RESULTS: The significantly highest value was obtained for Monobond Plus + Multilink Hybrid Abutment, the extraoral resin cement for both titanium alloy (35.1 MPa) and zirconia (32.9 MPa). For each resin, significantly higher DC values were obtained for the dual-cure mode compared with the self-cure mode. Regardless of the cure mode, Nexus Universal reached the highest DC (78.4%). DISCUSSION/CONCLUSIONS: In this study, the extraoral self-curing resin cement showed the higher bond strength values on zirconia and titanium alloy when associated with a universal primer. Some intraoral dual-cure resin cements showed closed performances when used with universal primers. There is no direct correlation between the degree of conversion of the resin cement and the shear bond strength obtained on the prosthetic materials tested.

Amniotic membrane grafting for a case of bilateral giant full-thickness macular hole in Alport syndrome after cataract surgery.

PURPOSE: To describe the surgical management of bilateral giant full-thickness macular hole with sudden onset two months after cataract surgery in a patient with Alport syndrome. METHODS: Observational, single-case report. RESULTS: A 54-year-old female with a history of Alport syndrome presented with severe bilateral visual loss two months after cataract surgery. The diagnosis of bilateral giant full-thickness macular hole was made. We found the absence of the internal limiting membrane and the inability to lift and peel a continuous posterior hyaloid sheet during surgical management with 25-gauge pars plana vitrectomy (left eye). Amniotic membrane grafting followed by gas tamponade were performed for hole closure. The hole remained closed but vision was poorly restored two months after. CONCLUSION: Cataract surgery in patients with Alport syndrome could promote early development of giant full-thickness macular hole. Collagen defects could underlie internal limiting membrane absence and the inability to properly peel the posterior hyaloid.

Hidden mysteries in ancient Egyptian paintings from the Theban Necropolis observed by in-situ XRF mapping.

The material study of ancient Egyptian paintings began with the advent of Egyptology during the 19th century. By the 1930s, a lot had already been sampled and described. The limited palette for example has been analysed from actual painted surfaces but also from pigments and painting tools retrieved on site. However, most of these studies took place in museums while the painted surfaces, preserved in funerary chapels and temples, remained somewhat estranged from this primary physical understanding. The artistic process has been also reconstructed, mainly from the information presented by unfinished monuments, showing surfaces at different stages of completion. A lot of this modern and theoretical reconstruction is, however, based on the usual archaeological guessing game that aims at filling the remaining blanks. Our interdisciplinary project has decided to experiment on-site with state-of-the-art portable analysis tools, avoiding any physical sampling, to see if our knowledge of the work of the ancient Egyptian painters and draughtsmen could be taken at a further stage, while based on physical quantification that could be seen as a stronger and more reliable foundation for a redefined scientific hypothesis. The use of XRF mapping has, for instance, been applied to a known case of correction by surface repaint, something that is supposedly rare in the ancient Egyptian formal artistic process, while another fully unexpected one was discovered during the analytic exploration of a royal representation. In both cases, the precise and readable imaging of the physical composition of the painted surface offers a renewed visual approach based of chemistry, that can be shared through a multi- and interdisciplinary approach. However, this also leads to a more complex description of pigment mixtures that could have multiple meanings, where the practical often leads towards the symbolic, and from there hopefully to a renewed definition of the use of colours in complex sets of ancient Egyptian representations. At this stage, though the progress in this on-site material assessment of ancient works of art definitely means astonishing progress, one humbly has to face the fact that these ancient treasures shall still retain part of their defining mysteries.

In vitro study evaluating the shear bond strength of metal brackets to lithium disilicate ceramic support using a universal adhesive / Étude in vitro évaluant l'adhérence des attaches métalliques orthodontiques collées à l'aide d'un adhésif universel aux céramiques en disilicate de lithium

Introduction: The number of adult patients who seek an orthodontic treatment is increasing. These patients often have lithium disilicate ceramic restorations. The orthodontist has to find a procedure to bond effectively brackets to these restorations. In 2011, a new family of adhesives was introduced, universal adhesives, which are capable of bonding to ceramic and are said "multi-mode" because they can be used in etching-rinse or self-etching protocol on tooth surface. The objective of this in vitro study was to evaluate the shear bond strength (SBS) of metal brackets to lithium disilicate ceramic support using a universal adhesive. Materials and Methods: Forty machinable lithium disilicate blocks (IPS e.max CAD, Ivoclar) were prepared according manufacturer's instructions. Each specimen was randomly assigned to one of four groups (n=9 or 10) defined by the pretreatment protocol. Protocol 1: Hydrofluoric Acid 9 % (HF) + Silane + Orthodontic adhesive (Transbond™ XT Light Cure Adhesive Primer, 3M ESPE), protocol 2: HF + Universal adhesive (UA) (Scotchbond Universal®, 3M ESPE), protocol 3: UA only, protocol 4 : Monobond Etch & Prime® (Ivoclar) + UA. Then, a bracket of upper cuspid (3M ESPE) was bonded to each specimen with a composite resin (Transbond™ XT, 3M ESPE). SBS was measured between ceramic and bracket with a universal testing machine. A one-way ANOVA (ANalysis Of Variance) followed by Tukey's post-hoc test was performed to investigate SBS differences between groups. Results: Protocol 2 (43 MPa) and protocol 4 (36 MPa) showed the highest SBS values and were statistically different from protocol 1 (25 MPa) and protocol 3 (21 MPa). Conclusion: Despite the lower bond values obtained in the study, but higher than the minimum expected, the application of UA alone appears to be a safe procedure that seems to provide sufficiently strong and resistant bonding between the ceramic and the bracket. However, clinical studies are needed before a recommendation can be made.

Introduction: Les traitements orthodontiques chez l'adulte se démocratisent. Ces patients ont souvent des restaurations en céramique en disilicate de lithium, sur lesquelles l'orthodontiste doit être à même de coller efficacement ses attaches. Or, les adhésifs universels, nouvelle famille d'adhésifs introduite en 2011, présentent un potentiel d'adhésion aux céramiques, en plus de pouvoir être utilisés en mode mordançage-rinçage ou auto-mordançant. L'objectif de cette étude in vitro était d'évaluer l'adhérence d'attaches métalliques à ces céramiques à l'aide d'un adhésif universel. Matériels et méthodes: Quarante blocs de céramique en disilicate de lithium (IPS e.max CAD, Ivoclar) ont été préparés selon les recommandations de cristallisation du fabricant. Chaque échantillon a été ensuite réparti aléatoirement en quatre groupes (n = 9 ou 10) selon le protocole de traitement de surface appliqué. Protocole 1 : Acide Fluorhydrique 9 % (HF) + Silane + Adhésif orthodontique (Transbond™ XT Light Cure Adhesive Primer, 3M ESPE), protocole 2 : HF + Adhésif universel (AU) (Scotchbond Universal®, 3M ESPE), protocole 3 : AU uniquement, protocole 4 : Monobond Etch & Prime® (Ivoclar) + AU. Une attache métallique de canine maxillaire (3M ESPE) a ensuite été collée sur chaque échantillon avec une résine composite (Transbond™ XT, 3M ESPE). La résistance en cisaillement a ensuite été mesurée entre la céramique et l'attache métallique. Une ANOVA (ANalysis Of Variance ou analyse de variance) suivie du test post-hoc de Tukey ont été réalisés pour étudier les différences d'adhérence entre les groupes. Résultats: Les protocoles 2 (43 MPa) et 4 (36 MPa) présentent des valeurs d'adhérence significativement supérieures à celles des protocoles 1 (25MPa) et 3 (21 MPa). Conclusion: Malgré de plus faibles valeurs d'adhérence obtenues dans l'étude, mais supérieures à celles minimales attendues, l'application seule de l'adhésif universel semble être une procédure sans danger qui procure une adhésion suffisamment forte et résistante entre la céramique et l'attache. Des études cliniques sont cependant nécessaires avant d'émettre une recommandation.

Shear Bond Strength of a Direct Resin Composite to CAD-CAM Composite Blocks: Relative Contribution of Micromechanical and Chemical Block Surface Treatment.

This study aims to compare the shear bond strength (SBS) of a direct resin composite to CAD-CAM resin composite blocks treated with different surface treatments: micromechanical, chemical or a combination of both. Eight CAD-CAM resin composite blocks, namely Brilliant Crios, Cerasmart 270, Vita Enamic, Grandio block, Katana Avencia, Lava Ultimate, Tetric CAD and Shofu Block HC were chosen. The micromechanical surface treatment protocols tested were hydrofluoric acid, polyacrylic acid or sandblasting, and the chemical one was a universal primer. These treated CAD-CAM blocks were tested to determine the SBS of a light-curing composite resin Z100 bonded to their surface. Two-way ANOVA followed by Tukey's post hoc test was used to investigate the difference in SBS. Failures were analyzed by Fisher's exact test. Bonding interfaces were examined by scanning electron microscopy. The micromechanical surface treatments give the highest SBS values: sandblasting appears to be the most efficient procedure for dispersed filler composite blocks, while hydrofluoric acid etching is preferable for polymer-infiltrated ceramic network (PICN) blocks. The use of universal primer does not improve SBS values on dispersed filler composite blocks. For PICN blocks, the use of universal primer significantly increases SBS values when combined with hydrofluoric acid etching.

Mechanical Properties of Fused Deposition Modeling of Polyetheretherketone (PEEK) and Interest for Dental Restorations: A Systematic Review.

The aim of this systematic review was to determine the optimal printing parameters for the producing of fused deposition modeling (FDM) 3D-printed polyetheretherketone (PEEK) elements with mechanical properties suitable for dental restorations. Indeed, the mechanical properties are a critical prerequisite for the study of other parameters, such as physical, aesthetic and biological properties. An exhaustive electronic search was carried out in the PubMed, Embase and Web of knowledge databases to gather all the studies evaluating the influence of the printing parameters on the obtained mechanical properties of FDM 3D-printed PEEK elements were selected. Initially, the search resulted in 614 eligible papers. Independent screenings of the abstracts were performed by two authors to identify the articles related to the question. Twenty-nine studies were selected, of which eleven were further excluded after reading of the full text, and finally, eighteen articles were included in this review. The studies were difficult to compare due to the variability of the printing parameters and the types of PEEK. However, it seems interesting to use a high infill rate, a high chamber temperature close to that of the printing temperature and a heat post-treatment to obtain 3D PEEK elements presenting properties adapted to use as dental restorations. The analysis of the available literature suggested that the properties of PEEK could make it an interesting material in dental restorations to be performed with FDM additive manufacturing.