Progress in Dental Adhesive Materials Cadenaro, M.; Josic, U.; Maravić, T. ...
Journal of Dental Research,
03/2023, Letnik:
102, Številka:
3
Book Review, Journal Article
Recenzirano
There have been significant advances in adhesive dentistry in recent decades, with efforts being made to improve the mechanical and bonding properties of resin-based dental adhesive materials. ...Various attempts have been made to achieve versatility, introducing functional monomers and silanes into the materials’ composition to enable the chemical reaction with tooth structure and restorative materials and a multimode use. The novel adhesive materials also tend to be simpler in terms of clinical use, requiring reduced number of steps, making them less technique sensitive. However, these materials must also be reliable and have a long-lasting bond with different substrates. In order to fulfill these arduous tasks, different chemical constituents and different techniques are continuously being developed and introduced into dental adhesive materials. This critical review aims to discuss the concepts behind novel monomers, bioactive molecules, and alternative techniques recently implemented in adhesive dentistry. Incorporating monomers that are more resistant to hydrolytic degradation and functional monomers that enhance the micromechanical retention and improve chemical interactions between adhesive resin materials and various substrates improved the performance of adhesive materials. The current trend is to blend bioactive molecules into adhesive materials to enhance the mechanical properties and prevent endogenous enzymatic degradation of the dental substrate, thus ensuring the longevity of resin–dentin bonds. Moreover, alternative etching materials and techniques have been developed to address the drawbacks of phosphoric acid dentin etching. Altogether, we are witnessing a dynamic era in adhesive dentistry, with advancements aiming to bring us closer to simple and reliable bonding. However, simplification and novelty should not be achieved at the expense of material properties.
Abstract Objectives The aim of the study was to evaluate the contraction stress, microhardness and polymerization kinetics of three self-adhesive cements vs. conventional dual-cure resin cement. ...Methods Cements tested were: RelyX Unicem (3M ESPE, St. Paul, MN, USA), MaxCem Elite (Kerr, Orange, CA, USA), Clearfil SA Cement (Kuraray, Tokyo, Japan) and Duolink (Bisco Inc., Schaumburg, IL, USA). Cements were irradiated with a LED-curing unit (bluephase, IvoclarVivadent) for 20 or 40 s and the contraction forces (N) generated during polymerization were continuously recorded for 6 h with a universal testing machine. Polymerization kinetics were monitored using micro-Raman spectroscopy and degree of conversion was calculated. Vickers microhardness was also recorded. All measurements were performed at 10 min and 6 h. Data were statistically analyzed by three-way ANOVA with repeated measures and Tukey's post hoc test ( α = 0.05). Results Irrespective of exposure time, stress analysis ranked in the following order: Clearfil SA Cement < MaxCem < RelyX Unicem ≤ Duolink ( p < 0.05). Stress was correlated with microhardness values ( p < 0.05). Kinetic curves showed that maximum degree of conversion was attained more quickly than maximum stress after light activation. Significance The conventional resin-based cement showed higher stress values than the self-adhesive cements. The results were material-dependent and probably correlated to the composition of each material.
•This work presents ADRIS, an open source, accessible, VR-based driving simulator.•The simulator can train and test the driving skills of people with disability.•Traffic volume, road type, ...visibility, and distractors can be customized.•ADRIS provides performance data to assess compliance with traffic rule.•The system collects electromyography to investigate driving-related mechanisms.
Independent living and transportation are crucial aspects for people living with a disability. After an injury, it is important to assess driving ability, in terms of physical and psychological conditions, and to test the effects of prescribed drugs. Within this framework, driving simulators are suitable tools for training driving skills; however, available tools are expensive or lack appropriate sets of behavioral measures to fully characterize the drivers’ ability.
This work presents the first step toward the development of ADRIS, a new open-source, accessible, realistic virtual reality simulator for training and testing driving skills of people with sensory-motor disability. This includes a prototype based on an open-source simulator for autonomous driving research (CARLA), with the addition of customized features such as adaptable driving controllers, a virtual reality headset, and the possibility to collect behavioral and physiological data. Also, the new system allows to set different environmental conditions, to include and control the timing of potentially dangerous situations, and to set scenarios with various difficulty levels.
Tests on 17 healthy participants demonstrated that the simulator is well tolerated in terms of discomfort, physical fatigue, and mental effort. Also, the system is easy to use and is capable of providing a realistic driving experience, allowing the extraction of reliable behavioral parameters.
ADRIS combines a high-fidelity virtual world, with customizable features specifically designed for the training and testing of people living with a disability, thus making it usable in many contexts such as home training, rehabilitation, education, and research.
Abstract Objectives This study examined the effect of chlorhexidine (CHX) content on degree of conversion (DC) and E -modulus of experimental adhesive blends. The hypothesis tested was that ...increasing concentrations of CHX result in decreased DC and E -modulus in relation to adhesive hydrophilicity. Methods Experimental adhesive blends with increasing hydrophilicity R2 (70% bisGMA, 28.75% TEGDMA); R3 (70% BisGMA, 28.75% HEMA); R4 (40% BisGMA, 30% TCDM, 28.75% TEGDMA); R5 (40% BisGMA, 30% BisMP, 28.75% HEMA) and different CHX concentrations (1 and 5%) were analyzed. 5% CHX could not be dissolved in R2. A differential scanning calorimeter was used to measure the DC of resin blends. Photopolymerized disks of the experimental comonomer mixtures ( n = 10/gp) were used to measure the E -modulus of each specimen using a biaxial flexure test. Data were analyzed with two-way ANOVA (resin type and CHX concentration) and Tukey's post hoc test. Results The addition of 1% CHX did not significantly alter the DC of R2 and R3. Significant decrease in R3 DC values was observed when 5% CHX was added. CHX significantly increased the DC of R4 and R5. 1% CHX reduced the E -modulus of all resins ( p < 0.05) except for R2, in which the E -modulus was significantly increased ( p < 0.05). 5% CHX significantly reduced the E -modulus of resins R3 to R5 ( p < 0.05). Significance In conclusion, increasing concentrations of CHX dissolved in resin blends had little adverse effect on DC but decreased the E -modulus 27–48% compared to controls. Solvation of CHX in ethanol prior to incorporation of CHX into R2 may permit higher CHX concentrations without lower polymer stiffness.
Precise calving monitoring is important for reducing the effects of dystocia in cows and calves. The C6 birth control system is an electronic device that detects the time of the expulsion phase ...during calving. Several 53 Holstein were fitted on Day 280 ± 5 of gestation with the C6 birth control system, which was left in place until confirmation of calving. Sensitivity and PPV of the system were calculated as 100 and 95%, respectively. The partum events occurring at the group fitted with the system where compared with the analogous occurred at 59 animals without device. When alarmed by the system farm staff were in the calving barn during the expulsion phase in 100% of cases. On the contrary the cows without the device were assisted only in 17% of cases (P < 0.001).
Highlights • Processes responsible for the degradation of resin-bonded interfaces are described. • Durability of the resin–dentin bond strength may be improved by inhibiting intrinsic collagenolytic ...activity. • Cross-linking agents may increase the durability of resin–dentin bonds by increasing the mechanical properties of the collagen matrix.
