Eroded dentin does not jeopardize the bond strength of adhesive restorative materials

This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva) and eroded dentin (pH cycling model - 3× / cola drink for 7 days). Specimens were then reassigned according to restorative material: glass ionomer cement (KetacTM Molar Easy Mix), resin-modified glass ionomer cement (VitremerTM) or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250). Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37ºC. The failure mode was evaluated using a stereomicroscope (400×). Bond strength data were analyzed with two-way ANOVA and Tukey's post hoc tests (α = 0.05). Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001). For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested

Erosive potential of different types of grape juices

The purpose of the present study was to evaluate the erosive potential of different types (concentrated and powdered) and commercial brands of industrialised grape juices. The pH of all five fruit drinks was measured at two time points: immediately after preparation and 24 hours later. Sixty specimens of bovine enamel were randomly allocated and immersed in different types of grape juice (n = 10) for 10 minutes four times a day for fifteen days. The enamel alteration was analysed using surface Knoop microhardness (KHN) and surface roughness (Ra) tests at baseline and on the 5th, 10th and 15th days of the experiment. Two way ANOVA, Tukey's post hoc and Pearson's correlation tests were used for statistical analysis (α = 5%). The grape juices presented pH values ranging from 2.9 to 3.5. All of the tested juices promoted significant enamel mineral loss (p < 0.05) on the first evaluation (5th day of immersion) and produced a significant increase in the mean roughness from the 10th day on when compared to the control group (p < 0.05). By the 15th day, all of the beverages had produced surface roughnesses that were significantly higher than that of the control group. The results suggest that all grape juices, regardless of their commercial presentation, present erosive potential

Clinical Relevance of Studies on the Accuracy of Visual Inspection for Detecting Caries Lesions: A Systematic Review

Although visual inspection is the most commonly used method for caries detection, and consequently the most investigated, studies have not been concerned about the clinical relevance of this procedure. Therefore, we conducted a systematic review in order to perform a critical evaluation considering the clinical relevance and methodological quality of studies on the accuracy of visual inspection for assessing caries lesions. Two independent reviewers searched several databases through July 2013 to identify papers/articles published in English. Other sources were checked to identify unpublished literature. The eligible studies were those which (1) assessed the accuracy of the visual method for detecting caries lesions on occlusal, approximal or smooth surfaces, in primary or permanent teeth, (2) used a reference standard, and (3) reported data about sample size and accuracy of the methods. Aspects related to clinical relevance and the methodological quality of the studies were evaluated. 96 of the 5,578 articles initially identified met the inclusion criteria. In general, most studies failed in considering some clinically relevant aspects: only 1 included study validated activity status of lesions, no study considered its prognosis, 79 studies did not consider a clinically relevant outcome, and only 1 evaluated a patient-centred outcome. Concerning methodological quality, the majority of the studies presented a high risk of bias in sample selection. In conclusion, studies on the accuracy of the visual method for caries detection should consider clinically relevant outcomes besides accuracy; moreover, they should be conducted with higher methodological quality, mainly regarding sample selection

Mechanical properties of high-viscosity glass ionomer cement and nanoparticle glass carbomer

Introduction. The lack of evidence regarding the best available material for restoring occlusal-proximal cavities in primary teeth leads to the development of new restorative material, with nanoparticles, in order to enhance mechanical properties, resulting in increased restoration longevity. Aim. To evaluate the Knoop hardness and bond strength of nanoparticles material glass carbomer cement (CAR) and high-viscosity glass ionomer cement (GIC) in sound and caries-affected dentin. Methods. Forty bovine incisors were selected and assigned into four groups (): SGIC, sound dentin and GIC; SCAR, sound dentin and CAR; CGIC, caries-affected dentin and GIC; and CCAR, caries-affected dentin and CAR. All groups were submitted to microshear bond strength (MPa). Knoop hardness was also performed. Bond strength values were subjected to two-way ANOVA and Tukey test. Knoop hardness data were subjected to one-way ANOVA. Results. GIC presented higher Knoop hardness () and bond strength () than CAR. Also, both materials showed better performance in sound than in caries-affected substrates (). The interaction between factors was not statistically different (). Conclusion. Despite nanoparticles, CAR shows inferior performance as compared to GIC for the two properties tested in vitro. Moreover, sound dentin results in better bonding performance of both restorative materials evaluated

Faithful Squashed Entanglement

Squashed entanglement is a measure for the entanglement of bipartite quantum states. In this paper we present a lower bound for squashed entanglement in terms of a distance to the set of separable states. This implies that squashed entanglement is faithful, that is, strictly positive if and only if the state is entangled. We derive the bound on squashed entanglement from a bound on quantum conditional mutual information, which is used to define squashed entanglement and corresponds to the amount by which strong subadditivity of von Neumann entropy fails to be saturated. Our result therefore sheds light on the structure of states that almost satisfy strong subadditivity with equality. The proof is based on two recent results from quantum information theory: the operational interpretation of the quantum mutual information as the optimal rate for state redistribution and the interpretation of the regularised relative entropy of entanglement as an error exponent in hypothesis testing. The distance to the set of separable states is measured by the one-way LOCC norm, an operationally-motivated norm giving the optimal probability of distinguishing two bipartite quantum states, each shared by two parties, using any protocol formed by local quantum operations and one-directional classical communication between the parties. A similar result for the Frobenius or Euclidean norm follows immediately. The result has two applications in complexity theory. The first is a quasipolynomial-time algorithm solving the weak membership problem for the set of separable states in one-way LOCC or Euclidean norm. The second concerns quantum Merlin-Arthur games. Here we show that multiple provers are not more powerful than a single prover when the verifier is restricted to one-way LOCC operations thereby providing a new characterisation of the complexity class QMA.Comment: 24 pages, 1 figure, 1 table. Due to an error in the published version, claims have been weakened from the LOCC norm to the one-way LOCC nor

The economic impact of two diagnostic strategies in the management of restorations in primary teeth : a health economic analysis plan for a trial-based economic evaluation

Background Different approaches have been used by dentists to base their decision. Among them, there are the aesthetical issues that may lead to more interventionist approaches. Indeed, using a more interventionist strategy (the World Dental Federation - FDI), more replacements tend to be indicated than using a minimally invasive one (based on the Caries Around Restorations and Sealants—CARS). Since the resources related to the long-term health effects of these strategies have not been explored, the economic impact of using the less-invasive strategy is still uncertain. Thus, this health economic analysis plan aims to describe methodologic approaches for conducting a trial-based economic evaluation that aims to assess whether a minimally invasive strategy is more efficient in allocating resources than the conventional strategy for managing restorations in primary teeth and extrapolating these findings to a longer time horizon. Methods A trial-based economic evaluation will be conducted, including three cost-effectiveness analyses (CEA) and one cost-utility analysis (CUA). These analyses will be based on the main trial (CARDEC-03/NCT03520309), in which children aged 3 to 10 were included and randomized to one of the diagnostic strategies (based on FDI or CARS). An examiner will assess children’s restorations using the randomized strategy, and treatment will be recommended according to the same criteria. The time horizon for this study is 2 years, and we will adopt the societal perspective. The average costs per child for 24 months will be calculated. Three different cost-effectiveness analyses (CEA) will be performed. For CEAs, the effects will be the number of operative interventions (primary CEA analysis), the time to these new interventions, the percentage of patients who did not need new interventions in the follow-up, and changes in children’s oral health-related quality of life (secondary analyses). For CUA, the effect will be tooth-related quality-adjusted life years (QALYs). Intention-to-treat analyses will be conducted. Finally, we will assess the difference when using the minimally invasive strategy for each health effect (∆effect) compared to the conventional strategy (based on FDI) as the reference strategy. The same will be calculated for related costs (∆cost). The discount rate of 5% will be applied for costs and effects. We will perform deterministic and probabilistic sensitivity analyses to handle uncertainties. The net benefit will be calculated, and acceptability curves plotted using different willingness-to-pay thresholds. Using Markov models, a longer-term economic evaluation will be carried out with trial results extrapolated over a primary tooth lifetime horizon. Discussion The main trial is ongoing, and data collection is still not finished. Therefore, economic evaluation has not commenced. We hypothesize that conventional strategy will be associated with more need for replacements of restorations in primary molars. These replacements may lead to more reinterventions, leading to higher costs after 2 years. The health effects will be a crucial aspect to take into account when deciding whether the minimally invasive strategy will be more efficient in allocating resources than the conventional strategy when considering the management of restorations in primary teeth. Finally, patients/parents preferences and consequent utility values may also influence this final conclusion about the economic aspects of implementing the minimally invasive approach for managing restorations in clinical practice. Therefore, these trial-based economic evaluations may bring actual evidence of the economic impact of such interventions. Trial registration NCT03520309. Registered May 9, 2018. Economic evaluations (the focus of this plan) are not initiated at the moment

Impact of a Tutored Theoretical-Practical Training to Develop Undergraduate Students’ Skills for the Detection of Caries Lesions: Study Protocol for a Multicenter Controlled Randomized Study

Background: Tutored laboratorial activities could be a manner of improving the competency development of students. However, its impact over conventional theoretical classes has not yet been tested. Additionally, different university contexts could influence this issue and should be explored. Objective: To assess the impact of a tutored theoretical-practical training for teaching undergraduate students to detect caries lesions as compared with theoretical teaching activities. The impact of these teaching/learning activities will be assessed in terms of efficacy, cost/benefit, retention of knowledge/acquired competences, and student acceptability. Methods: Sixteen centers (7 centers from Brazil and 9 centers from other countries throughout the world) are involved in the inclusion of subjects for this protocol. A randomized controlled study with parallel groups will be conducted. One group (control) will be exposed to a 60- to 90-minute conventional theoretical class and the other group (test) will be exposed to the same theoretical class and also a 90-minute laboratory class, including exercises and discussions based on the evaluation of a pool of images and extracted teeth. The mentioned outcomes will be evaluated immediately after the teaching activities and also in medium- and long-term analyses. To compare the long-term outcomes, students who enrolled in the university before the participating students will be interviewed for data collection and these data will be used as a control and compared with the trained group. This stage will be a nonrandomized phase of this study, nested in the main study. Appropriate statistical analysis will be performed according to the aims of this study. Variables related to the centers will also be analyzed and used to model adjustment as possible sources of variability among results. Results: This ongoing study is funded by a Brazilian national funding agency (CNPq- 400736/2014-4). We expect that the tutored theoretical-practical training will improve the undergraduate students’ performance in the detection of caries lesions and subsequent treatment decisions, mainly in terms of long-term retention of knowledge. Our hypothesis is that tutored theoretical-practical training is a more cost-effective option for teaching undergraduate students to detect caries lesions. Conclusions: If our hypothesis is confirmed, the use of laboratory training in conjunction with theoretical classes could be used as an educational strategy in Cariology to improve the development of undergraduate students’ skills in the detection of caries lesions and clinical decision-making

Glass ionomer cement hardness after different materials for surface protection

The aim of the present study was to evaluate the Knoop hardness of high viscous glass ionomer cement (GIC) Ketac™ Molar Easy Mix (3M ESPE, Saint Paul, USA) submitted to different types of compounds for surface protection. Sixty specimens of GIC were made in PVC molds with 7.5 mm diameter and 2.5 mm thickness. Divided in 6 groups: G1, Control (no protection); G2, Cavitine® (Copal varnish); G3, Magic® bond (Adhesive); G4, Adper™ Single Bond 2 (Single bottle adhesive); G5, Solid Petroleum Jelly; G6, Nail Varnish. The surface protection was applied after initial setting reaction. The specimens were immersed in deionized water, at 37°C, for 24 h. The surfaces were polished in a rotation machine (Aropol 2V). The hardness test was accomplished in a Digital Microhardness tester HVS-100. In each specimen five indentations were done and repeated after 30 days and 4 months, under the same conditions. The results were submitted to Two-way ANOVA and Tukey Test. The only material that differed from the control group was the nail varnish (p < 0.001), with the other materials showing no significant difference from the control group. It was concluded that the best material for surface protection of GIC was the nail varnish, but because of possible harmful effects, petrolleum jelly could be a better option

Glass carbomer and compomer for ART restorations: 3-year results of a randomized clinical trial

Objective: To evaluate the survival of atraumatic restorative treatment (ART) restorations using high viscosity glass ionomer cement (GIC), compomer (COM), and glass carbomer (CAR) for occlusal and occlusoproximal cavitated dentin caries lesions in primary molars. Methods: A total of 568 4–7-year-old children (287 occlusoproximal and 281 occlusal cavities) were selected in Barueri, Brazil. The patients were randomly allocated in three groups: GIC, COM, and CAR. All treatments were performed on school setting following ART premises. Evaluations were performed after 2, 6, 12, 18, 24, and 36 months. Restoration survival was evaluated using Kaplan-Meier survival analysis and log-rank test, while Cox regression analysis was used for testing association with clinical factors (α = 5%). Results: The overall survival rate after 3 years of occlusal ART restorations was 73% (GIC = 83%; COM = 78%; CAR = 62%) and 49% for occlusoproximal ART restorations (GIC = 56%; COM = 56%; CAR = 36%). CAR restorations were less successful than GIC and COM for both occlusal and occlusoproximal restorations (p 0.05). Conclusions: GIC and compomer are clinically more successful than CAR for occlusal and occlusoproximal restorations in primary molars. Clinical significance: Both compomer and high viscosity glass ionomer cement are suitable materials for ART in primary molars. However, glass carbomer cement should not be used for ART (#NCT02217098)