Positive Influence Of A Dental Anaesthesia Simulation Model On The Perception Of Learning By Mexican Dental Students

Introduction: This study evaluated the influence of 3-repetition training with a dental anesthesia simulation model (DASM) on the perception of learning by dental students. Materials and methods: Dental students who had never used a dental anesthesia technique were randomly divided into 2 groups that were taught the anterior superior alveolar nerve infiltrative anesthesia technique. Group 1 (G1, N=10) followed a 3-stage learning method: 1st) theoretical lecture, 2nd) clinical demonstration, and 3rd) DASM training, including 3 repetitions of the anesthesia technique. Group 2 (G2, N=10) followed only the 1st and 2nd stages. The students in both groups then performed the anesthesia technique. The perception of the students was evaluated by 4 learning concepts. Each was evaluated with a 5-point Likert Scale questionnaire. The average score of each item of the questionnaire for G1 was compared with that of G2. Statistically significant differences were identified with the Mann-Whitney test. The average working time of each group was timed and compared by Student’s t-test to identify possible statistically significant differences. Results: Students in G1 showed higher average scores of perception in controlling the handling of the dental syringe and confidence in performing the injection (p\u3c0.05), and showed an average working time shorter than that of the students in G2 (p\u3c0.05). Conclusion: The DASM positively influenced the perception learning of the dental students; it increased their confidence and syringe handling ability, as well as skills to perform the injection of anesthesia more quickly

Bacterial Percolation and Sealer Tubular Penetration in a Polymer-based Obturation System Compared with Warm Vertical Condensation Technique: An in Vitro Study

Introduction: This study compared bacterial percolation and sealer penetration of a novel obturation technique with the ones of warm vertical condensation technique. Methods and Materials: A bacterial percolation test was carried out with 80 single rooted human teeth divided into 5 groups;  A (n=20): warm vertical condensation and AH-Plus, B (n=20): CPoint with AH-Plus, C (n= 20): CPoint with EndoSequence BC, +ve Control (n=10): teeth with no canal obturation, -ve Control (n=10): teeth with no access cavity. The samples were inoculated with a multispecies bacterial incoulum. Bacterial percolation was evaluated by turbidity. Confocal laser scanning microscopy (CLSM) was used to observe the presence of gaps and voids. Further 48 extracted human mandibular single-canal premolars were used to determine the sealer penetration. Slices of the samples were observed by CLSM to evaluate tubules penetration of the sealer. Kaplan Meyer survival, ANOVA one way and Tuckey HSD test and a Wilcoxon signed-rank test were utilised. Results: A Kaplan-Meier test showed no significant difference overall (P>0.05) between groups A, B and C. At 43 days, the group B showed a significantly inferior ability to prevent bacterial passage (P<0.05). The group C showed a deeper sealer penetration than group A and B with statistically significant differences (P<0.05) for the total penetration (ANOVA one way and Tukey HSD). A Wilcoxon signed-rank test showed statistically significant differences for the penetration in the middle-and apical third of the 3 groups. Conclusion: Based on this in vitro study, the single polymer-cone obturation technique with a resin based- and bioceramic based-sealer behaved similarly to the warm vertical obturation technique in preventing bacterial passage. The bioceramic sealer showed the deepest penetration but did not fully prevent bacterial leakage

Poly(2-dimethylamino ethylmethacrylate)-Based Polymers To Camouflage Red Blood Cell Antigens

peer reviewedPoly(2-dimethylamino-ethylmethacrylate) (PDMAEMA) is a cationic polymer when dissolved in a 7.4 pH fluid. Owing to its ionic nature, this polycation interacts with the negatively charged cell membrane surface of red blood cells (RBCs). The electrostatic self-assembly of PDMAEMA on RBCs membrane can be employed for inducing the formation of a polymeric shield camouflaging blood group antigens on RBCs as a valuable strategy for developing “universal RBCs” for blood transfusion. The purpose of this research was to evaluate the camouflaging ability of PDMAEMA homopolymers and PDMAEMA-copoly(nethylene glycol) copolymers differing in molecular weight and architecture. Surprisingly, the PDMAEMAs caused a partially masking, no masking, and sensitization of the same RBCs population. The MW and architecture of the polymers as well as temperature of PDMAEMA-RBCs treatment influenced the results observed. Herein, the very particular reactivity of PDMAEMAs and RBCs is analyzed and discussed

Sustained Release Of Calcium Hydroxide From Poly(DL-lactide-co-glycolide) Acid Microspheres For Apexification

Calcium hydroxide (Ca(OH)2) loaded poly(DL-lactide-co-glycolide) acid (PLGA) microspheres (MS) might be employed for apexification requiring a sustained release of Ca++. The aim of this study was to formulate and characterize Ca(OH)2-PLGA-MS. The Ca(OH)2-loaded MS were prepared by either oil-in-water (O/W) or water-in-oil/in-water (W/O/W) emulsion solvent evaporation technique. MS produced by the O/W technique exhibited a larger diameter (18.63 ± 7.23 μm) than the MS produced by the W/O/W technique (15.25 ± 7.37 μm) (Mann Whitney U test P \u3c 0.001). The Ca(OH)2 encapsulation efficiency and Ca++ release were calculated from data obtained by absorption techniques. Ca++ release profile was evaluated for 30 days. The percentage of encapsulation efficiency of the O/W-produced MS was higher (24%) than the corresponding percentage of the W/O/W-produced MS (11%). O/W- and W/O/W-produced MS released slower and lower Ca++ than a control Ca(OH)2 paste with polyethylene glycol 400 (ANOVA 1 way, Tukey HSD P \u3c 0.01). O/W-produced MS released higher Ca++ than W/O/W-produced MS (statistically significant differences with t-Student test). We concluded that Ca(OH)2-PLGA-MS were successfully formulated; the technique of formulation influenced on the size, encapsulation efficiency and release profile. The MS were better sustained release system than the Ca(OH)2 paste

In vitro hemocompatibility of nanocarriers tailored for biopharmaceutical drugs.

The optimization of nanoparticles (NP) for drug delivery, in particular to target the BBB, imposes to verify their hemocompatibility both for toxicological and efficiency of targeting perspectives. Indeed the large surface they are able to expose to the biological environment promotes their interaction with various biochemicals, in particular proteins which can after adsorption elicit the activation of biological cascades either responsible from NP clearance or/and harmful body reaction (inflammatory / coagulation). In the frame of the European Integrated Project : “Nanobiopharmaceutics”, we have the opportunity to compare the hemoreactivity of about 145 different NP samples differing in core and surface chemistry and classified according to their expected difference in hydrophobicity based on the nature of their core materials. According to this classification, PLGA nanoparticles, polyglycidol-polyethyethylene oxide nanoparticles, polyglycidol thyolated or polyacrylamide nanogels, and polyelectrolyte complexes either based on polyamidoamine or poly(N,N-dimethylamino- 2-ethylmethacrylate) have been evaluated within a concentration ranging from 0.3 to 1000 μg/mL. These in vitro tests have been realized for screening purpose adopting normal human bloods and according to Iso 10993. As a summary of this extensive study, our results clearly highlight that most of the polymeric nanoparticles evaluated give rise to some alterations of the blood components. In particular the platelets, intrinsic pathway of coagulation and complement activation are the most reactive biological parameters in the presence of these nanostuctures. Although not strictly related to the surface chemistry our classification has also allowed us to derive some clear correlations between nanomaterial properties and their hemoreactivity. Within the class of polyelectrolyte electrolyte complexes, the modifications brought in the surface chemistry has drastically improved their hemoreactivit

Impact of two distinct dental anesthesia simulation models on the perception of learning by students

We evaluated an infiltration anesthesia simulation model (IAM) and a conduction anesthesia simulation model (CAM) on the perception of learning by Mexican dental students. Our aim was to compare the perception of learning by dental students trained with two distinct dental anesthesia simulation model (DASM) with dental students who were not trained with a DASM. 3 groups participated in the study: G1 (N=12 students) learned to block the mental nerve (BMN) by participating in a theoretical lecture (stage 1) and a clinical demonstration (stage 2); G2 (N=12 students) learned the BMN by participating in the stage 1, stage 2, and training with the CAM; G3 (N=12 students) learned the BMN by participating in the stage 1, stage 2, and training with the IAM. The groups performed the BMN in a clinical exercise. Working-time of all participants was timed. Perception of learning for all participants was evaluated with a 5-point Likert Scale. The results showed that statistically significant differences were found between score of G1 and score of G2 and score of G3 (P<0.05).  No statistically significant differences were found between scores of G2 and scores of G3. G1, G2 and G3 showed an average working-time of 12:42 minutes, 9.75 minutes and 8:03 minutes, respectively (P<0.05). We concluded that the IAM and CAM showed a positive impact on the perception of learning, and the students trained with the IAM showed a shorter working time compared with the students trained with the CAM.En este estudio se evaluó el impacto de un modelo de simulación de anestesia dental por infiltración (IAM) y de un modelo de simulación de anestesia dental por bloqueo (CAM) en la percepción del aprendizaje en estudiantes mexicanos en estomatología. El objetivo fue comparar la percepción en el aprendizaje de estudiantes que entrenaron empleando dos distintos modelos de simulación de anestesia dental con estudiantes que no recibieron entrenamiento empleando algún modelo de simulación de anestesia dental. Participaron 3 grupos en el estudio: G1 (n=12) aprendieron el bloqueo del nervio mentoniano (BNM) al participar en una clase teórica (sesión 1) y en una demostración clínica (sesión 2); G2 (n=12) aprendieron la técnica de anestesia del BNM al participar en la sesión 1, sesión 2 y entrenando con el CAM; G3 (n=12) aprendieron la técnica del BNM al participar en la sesión 1, sesión 2 y entrenando con el IAM. Los grupos aplicaron la técnica del BNM en un ejercicio clínico. Se midió el tiempo de trabajo de los participantes. La percepción del aprendizaje de los participantes se evaluó con una Escala de Likert de 5 ítems. Los resultados mostraron diferencias estadísticamente significativas entre los valores del G2 y del G3 en comparación con el G1. No se encontraron diferencias estadísticas entre los valores del G2 y del G3. El tiempo de trabajo para el G1, G2 y G3 fue respectivamente de: 12:42 minutos, 9.75 minutos y 8:03 minutos, (P<0.05). Se concluyó que el IAM y el CAM mostraron un impacto positivo en la percepción del aprendizaje; los estudiantes entrenados con el IAM mostraron un tiempo de trabajo más corto en comparación con los estudiantes entrenados con el CAM.

Are Mechanical Vibrations an Effective Alternative to Accelerate Orthodontic Tooth Movement in Humans? A Systematic Review

The objective of this article was to conduct a systematic review of the literature to contrast the existing evidence on the effect of mechanical vibrations, either high or low frequency, as an alternative to accelerate orthodontic tooth movement in humans. A literature search from 2010 to June 2021 was conducted in the electronic databases: PubMed, NCBI, Google Scholar, EBSCO, Cochrane, and Ovid, using the eligibility criteria to identify the studies. Only randomized clinical trials (RCT) were included. The certainty of the evidence was assessed using the GRADE tool and the risk of bias (RoB) in individual studies was evaluated according to the Cochrane bias risk tool. Fifteen RTCs were included for final review. Overall, the RoB was classified as low (3), moderate (5), and high (7). Three articles with low RoB, four with moderate RoB, and four with high RoB found no significant effect in the use of vibrations on orthodontic movement. Only four articles, three of them with high RoB and one with moderate RoB, found that mechanical vibrations are effective at accelerating orthodontic tooth movement. The results seemed to indicate that there is no evidence that vibratory stimuli can increase the rate of dental movement or reduce neither the time of dental alignment nor canine retraction during orthodontic treatment. It is important to note that a greater number of high-quality randomized controlled trials are urgently needed

Hemocompatibility assessment of poly(2-dimethylamino ethylmethacrylate) (PDMAEMA)-based polymers

Poly(2-dimethylamino-ethylmethacrylate) (PDMAEMA), a cationic polymer, has been widely reported as a nonviral carrier. Despite the fact that the cytotoxicity of this polymer has been extensively studied, there is a lack of information about its blood compatibility. Hence, this work evaluates the hemocompatibility of free-form PDMAEMA homopolymers differing in molecular weight (Mw) with or without a poly(ethylene glycol) (PEG) sequence in the form of a palm tree-like structure. Poly(ethylenimine) (PEI) was used as a reference in order to compare its hemoreactivity. Hemagglutination, hemolysis, platelet number, blood coagulation, and the complement systems were assessed in normal human whole blood according to the ISO 10993-4. Results showed that Mw, concentration, and incubation time strongly affected the hemocompatibility of the polymers evaluated. Our in vitro observations highlight that PDMAEMA homopolymers interacted strongly with the surface of the red blood cells but not with the inner structure of the membrane, while PEI behaved in the opposite way. No clear correlation has been evidenced between PDMAEMA-induced hemagglutination, PEI-induced hemagglutination, and hemolysis. Interestingly, if these polyelectrolytes strongly affect the platelets and blood coagulation cascades in a dose dependent way, none of them significantly affects the complement system. Our work reveals new knowledge on the toxicology of 2 families of polycations largely explored for gene delivery and on their mechanisms of cellular and humoral interactions