Influence of the CAD-CAM Systems on the Marginal Accuracy and Mechanical Properties of Dental Restorations.

The aim of this study was to compare the quality of different computer-assisted-design and computer assisted manufacturing systems (CAD-CAM) generated by only one scanner, focusing on vertical fit discrepancies and the mechanical properties. A master model was obtained from a real clinical situation: the replacement of an absent (pontic) tooth, with the construction of a fixed partial denture on natural abutments with three elements. Nine scans were performed by each tested and 36 copies were designed using a dental CAD-CAM software (Exocad). The frameworks were manufactured using three-axis and five-axis, with the same batch of the chrome-cobalt (CrCo) alloy. The frameworks were not cemented. A focus ion beam-high resolution scanning electron microscope (FIB-HRSEM) allowed us to obtain the vertical gap measurements in five points for each specimen. Roughness parameters were measured using white light interferometry (WLI). The samples were mechanically characterized by means of flexural tests. A servo-hydraulic testing machine was used with a cross-head rate of 1 mm/min. One-way ANOVA statistical analysis was performed to determine whether the vertical discrepancies and mechanical properties were significantly different between each group (significance level p < 0.05). The overall mean marginal gap values ranged: from 92.38 ± 19.24 µm to 19.46 ± 10.20 µm, for the samples produced by three-axis and five-axis machines, respectively. Roughness was lower in the five-axis machine than the three-axis one, and as a consequence, the surface quality was better when the five-axis machine was used. These results revealed a statistically significant difference (p < 0.005) in the mean marginal gap between the CAD-CAM systems studied. The flexural strength for these restorations range from 6500 to 7000 N, and does not present any statistical differences' significance between two CAD-CAM systems studied. This contribution suggests that the number of axes improves vertical fit and surface quality due to the lower roughness. These claims show some discrepancies with other studies.

Teoría de la decisión y cribado del Síndrome de Down: cálculo individualizado del dintel de normalidad / Decision making and Down Syndrome screening: individualized cutoff

Objetivos: demostrar mediante la teoría de la decisión que el cribado bioquímico-ecográfico del síndrome de Down no debe aplicarse de forma universal sino teniendo en cuenta los umbrales de decisión. Desarrollar el cálculo matemático individualizado para cada gestante de los umbrales de decisión siguiendo el modelo de Pauker-Kassirer. Implementar un método simple para la obtención individualizada de las utilidades que intervienen. Material y métodos: definimos un diagrama de influencia con: variables aleatorias: tener Síndrome de Down, resultado del cribado, pérdida gestacional tras amniocentesis. Decisiones: aplicar el cribado, realizar amniocentesis. Utilidades relativas a los diferentes resultados posibles calculadas en un grupo de 10 gestantes consecutivas mediante diagramas de equivalencia temporal para el cálculo del tiempo de vida ajustado en calidad. Realizamos un análisis de sensibilidad comparando la utilidad de cada estrategia en función de la probabilidad a priori. Los cálculos fueron realizados con OpenMarkov (http://www.openmarkov.org). Resultados: con las utilidades obtenidas (tener un hijo sano 1; tener un hijo con síndrome de Down 0,57; interrumpir el embarazo por diagnóstico de síndrome de Down 0,90; pérdida gestacional secundaria a amniocentesis 0,80) en gestantes con una probabilidad a priori mayor de 0,014 (Odds de 1/70, corresponde al riesgo de una gestante de 41 años) se obtiene la máxima utilidad realizando directamente una amniocentesis. Al resto deberemos aplicar el cribado porque el umbral diagnóstico (0,0002) es menor que el riesgo en las gestantes más jóvenes. Discusión: la gran variabilidad interindividual de las utilidades aconseja que el cálculo de los umbrales de decisión se individualicen para cada gestante; para ello proponemos un método matemático basado en Pauker-Kassirer (AU)

Objectives: To evaluate by decision making if biochemical and ultrasonographic universal screening of Down syndrome is accurate, or they must be used in a selective way related to decision thresholds. To develope a probabilistic model to calcule the decision thresholds following Pauker-Kassirer model. To design a method of utility assessment to quantify women´s individual preferences. Material and methods: An influence diagram with uncertainty nodes (affected or unaffected birth, positive or negative screening, amniocentesis related miscarriage or no complicated technique), decision nodes (to perform screening, to perform amniocentesis) and utilities was developed. Utilities were the average of 10 consecutive pregnant women preference measures using the time trade-off model to obtain quality-adjusted life years. A sensitivity analysis comparing utility for every strategy related to prior probability was done. To perform mathematical results the free software programme OpenMarkov (http://www.openmarkov.org) was used. Results: Utilities were: unaffected birth 1, Down syndrome-affected birth 0.57, elective abortion after Down syndrome diagnosis 0.9 and amniocentesis procedure related miscarriage 0.8. Over 41 year-old risk (Odds 1/70) invasive diagnostic testing has the maximum expected utility. The testing threshold is lower than the lowest-risk women. Therefore, screening is the best option under that prior probability. Discussion: We agree with prior published data: current cutoff is not appropriate because it assumes that women value equally burdensome procedure-related miscarriage of a normal fetus and Down syndrome-affected birth. There was a substantial subject-to-subject variation; individual preferences should be used to stablish a personalised cutoff following Pauker-Kassirer model (AU)

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions.

Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility). Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW), coffee (CF), Coca-Cola (CC), red wine (RW), tea (TE) and orange juice (OJ). The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE) were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher's post-hoc test and Pearson's correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17-1.759)); Vertise Flow in CF (∆E = 14.75 (7.91-27.41)), in TE (∆E = 7.27 (2.81-24.81)) and OJ (∆E = 3.17 (0.87-9.92)); Tetric EvoFlow® in CC (∆E = 1.27 (0.45-4.02)); and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23-19.59)). RW caused the most discoloration (∆E = 23.62 (4.93-51.36)). Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19). The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem.

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions

Abstract Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility). Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW), coffee (CF), Coca-Cola (CC), red wine (RW), tea (TE) and orange juice (OJ). The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE) were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher's post-hoc test and Pearson's correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17-1.759)); Vertise Flow in CF (∆E = 14.75 (7.91-27.41)), in TE (∆E = 7.27 (2.81-24.81)) and OJ (∆E = 3.17 (0.87-9.92)); Tetric EvoFlow® in CC (∆E = 1.27 (0.45-4.02)); and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23-19.59)). RW caused the most discoloration (∆E = 23.62 (4.93-51.36)). Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19). The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem.

Self-reported Oral Hygiene Habits in Smokers and Nonsmokers Diagnosed with Periodontal Disease.

PURPOSE: To determine whether smokers report having less adequate oral hygiene habits than nonsmokers. MATERIALS AND METHODS: Using a 24-item questionnaire addressing both smoking and oral hygiene habits, patients from three periodontal practices in Spain were evaluated. In order to assess the periodontal status of all patients, immediately following the survey, the patients were examined clinically and categorised according to the American Dental Association (ADA) classification for periodontal diseases. RESULTS: 762 patients with ADA type I gingivitis (4.1%), type II early periodontitis (31.2%), type III moderate periodontitis (39.2%) and type IV advanced periodontitis (25.5%) were surveyed. A total of 289 smokers (38.0%) and 402 (52.8%) nonsmokers participated in the study: 77 (10.1%) participants were identified as heavy smokers (>20 cigarettes/day), along with 122 (16.0%) moderate smokers (10-20 cigarettes/day) and 90 (11.8%) light smokers (<20 cigarettes/day). A greater proportion of nonsmokers brushed their teeth two (37.8%) or more (22.9%) times a day compared with moderate smokers (twice: 32.0%, more: 15.6%) and heavy smokers (twice: 32.5%, more: 15.6%), respectively (p < 0.05). Heavy smokers used dental floss statistically significantly less frequently (10.4%) than nonsmokers (21.6%) (p < 0.05). No statistically significant differences were found between smokers and nonsmokers regarding the use of mouthwashes (p > 0.05). CONCLUSIONS: This study revealed comparable oral hygiene habits in nonsmokers and light smokers. However, heavy smokers were found to have worse oral hygiene habits than nonsmokers.

Dental pulp of the third molar: a new source of pluripotent-like stem cells.

Dental pulp is particularly interesting in regenerative medicine because of the accessibility and differentiation potential of the tissue. Dental pulp has an early developmental origin with multi-lineage differentiation potential as a result of its development during childhood and adolescence. However, no study has previously identified the presence of stem cell populations with embryonic-like phenotypes in human dental pulp from the third molar. In the present work, we describe a new population of dental pulp pluripotent-like stem cells (DPPSCs) that were isolated by culture in medium containing LIF, EGF and PDGF. These cells are SSEA4(+), OCT3/4(+), NANOG(+), SOX2(+), LIN28(+), CD13(+), CD105(+), CD34(-), CD45(-), CD90(+), CD29(+), CD73(+), STRO1(+) and CD146(-), and they show genetic stability in vitro based on genomic analysis with a newly described CGH technique. Interestingly, DPPSCs were able to form both embryoid-body-like structures (EBs) in vitro and teratoma-like structures that contained tissues derived from all three embryonic germ layers when injected in nude mice. We examined the capacity of DPPSCs to differentiate in vitro into tissues that have similar characteristics to mesoderm, endoderm and ectoderm layers in both 2D and 3D cultures. We performed a comparative RT-PCR analysis of GATA4, GATA6, MIXL1, NANOG, OCT3/4, SOX1 and SOX2 to determine the degree of similarity between DPPSCs, EBs and human induced pluripotent stem cells (hIPSCs). Our analysis revealed that DPPSCs, hIPSC and EBs have the same gene expression profile. Because DPPSCs can be derived from healthy human molars from patients of different sexes and ages, they represent an easily accessible source of stem cells, which opens a range of new possibilities for regenerative medicine.

Comparative study of the microtensile bond strength of three different total etch adhesives with different solvents to wet and dry dentin (in vitro test).

The aim of this study was to compare the microtensile bond strength of three different total etch adhesives: XP Bond (Caulk-Dentsply) versus Excite (Ivoclar/Vivadent) and Prime & Bond NT (Caulk-Dentsply). Forty two (42) third human molars were cut to expose the dentinal surface. They were divided into three groups of 14 teeth (GI: XP Bond, G2: Excite, G3: Prime & Bond NT) and two groups of seven teeth for each moisture condition: moist dentin (GM) and dry dentin, (GD). The total-etch technique was used with each moisture variation. The adhesives and composites A3 (Ceram Duo GI, G3 and Tetric Ceram G2) were applied according to manufacturer's instructions. Teeth were cut with an ISOMET 1000 (Buehler Ltd.) to obtain 1 mm2 x 10 mm bars, which were subject to a traction test at 5 mm/min in a universal testing machine (Adamel Lhomargy DY 36). The collected data were recorded and analyzed using an experimental design for studying two factors offixed effrcts with software Statgraphics version 5.1. For the variable type of adhesive, we found p = 0.000, for the variable substrate condition, p = 0.0012, and for interaction between both factors, p = 0.0457, which indicates significant statistical differences. The values for microtensile bond strength were G1M = 55.0642 MPa Standard deviation (SD) 3.09768; G1D 39.115 MPa SD 2.86789; G2M 34.1607 MPa SD 2.86789; G2D = 32.7373 MPa SD 2.77065; G3M 3 7.3407 MPa SD 2.86789 and G3D = 31.0593 MPa SD 2.77065. XP Bond showed the greatest values of micmtensile bond strength under both conditions. Moist substrate increases the values of micmtensile bond stren gth]br the adhesives tested; howeve, Excite shows lower susceptibility to variation of dentinal moisture.

Atención continuadaen la zona de Valtierra-Cadreita(Navarra) / Continued healthcare in the Valtierra-Cadreita area (Navarra)

Objetivos: identificar las características de la población que acudea los servicios de Atención Continuada (AC), el tipo de atencióndemandada, las técnicas y procedimientos enfermeros quese llevan a cabo y las derivaciones que se hacen al hospital.Material y métodos: estudio descriptivo transversal en una poblaciónde 15.000 personas del entorno rural que acudió a losservicios de AC, tanto de presencia física como localizada duranteun año (entre 2005 y 2006). Además de las técnicas y procedimientosrealizados a cada paciente, se registró edad, sexo,localidad, hora del aviso, atención domiciliaria o centro y derivacióndel paciente.Resultados: se atendieron 1.730 pacientes, 669 con atenciónlocalizada y 1.061 en la zona con presencia física. El grupo másdemandante fue el comprendido entre 76-80 años de edad,con 152 visitas (8,78%). Acudieron más los hombres (58%) quelas mujeres. Un 70% de los avisos fueron en horario de tarde.En la zona con presencia física, la atención a los pacientes serealizó fundamentalmente en el centro de salud (62%). Se derivarona 220 pacientes (13%) al centro hospitalario más cercano.Las curas fueron la técnica más realizada (n=393, 37%).Conclusiones: la zona más demandante es aquélla con presenciafísica, la población más demandante es la anciana y ungrupo importante de mediana edad. Acuden también más loshombres y en la franja horaria de la tarde sobre todo. Un reducidoporcentaje es derivado al hospital. El estudio permitióidentificar las técnicas y procedimientos más frecuentementerealizados. Los hallazgos encontrados han posibilitado hacercambios para la mejora de la calidad (AU)

Objectives: to identify the characteristics of the populationwho seek continued medical healthcare, the type of healthcareservice sought, nursing techniques and procedures thatare carried out and hospital referrals.Material and methods: cross-sectional, descriptive study of apopulation comprised of 15,000 people from a rural setting whosought continued healthcare (CH) services, both at the pointof care (hospital or ambulatory setting) and localized (domiciliarycare or nursing home), throughout one year (between2005 and 2006). Aside from techniques and procedures performedon each patient, age, sex, city/town of residence, timeof consultation request, domiciliary care or centre and patientreferral were registered.Results: a total of 1,730 patients were seen, of whom 669 requireddomiciliary care and 1,061 required care in the area’spoint of care. The group which most sought healthcare serviceswas the one ranging between 76 and 80 years of age,with 152 visits (8,78%). More men (58%) than women soughthealthcare services. 70% of visits took place in the afternoon.In the point of care, healthcare delivery to patients was performedmainly in the health centre (62%). 220 patients (13%)were referred to the nearest hospital. Wound care was the mostfrequently performed technique (n=393, 37%).Conclusions: the most requested area is the one at the point ofcare. The elderly and an important middle-age group constitutethe population with the highest number of requests. Moremen than women seek healthcare services. Visits take placeespecially in the afternoon. A small percentage of patients isreferred to the hospital. The study enabled us to identify the mostfrequently performed techniques and procedures. Our findingshave allowed us to make changes with a view to improvethe quality of the service provided (AU)