The Effect of Touch-Cure Polymerization on the Conversion and Hardness of Core Build-Up Resin Composites: A Laboratory Study.

To improve the self-curing capacity and interfacial strength with dentine of dual-cured composite materials, touch-cure activators have been introduced. The aim of the study was to evaluate the effect of these activators on the hardness and conversion of dual-cured resin composite core build-up restoratives. The materials tested were Clearfil DC Core Plus (CF) and Gradia Core (GC) with the corresponding adhesives Clearfil S3 Bond Plus (for CF) and G-Premio Bond/G-Premio DCA activator (for GC). Disk-shaped specimens (n = 6/group) were prepared for the following groups: dual-cured, self-cured and self-cured in contact with the adhesive activators at the bottom surface. After a 3-week storage period (dark/dry/37 °C) the Martens hardness (HM) and degree of conversion (DC%) were determined for the previously mentioned groups and the top surfaces of groups in contact with the adhesives. A statistical analysis was performed by a one-way ANOVA and Holm-Sidak test per material and a Pearson's correlation analysis (HM vs. DC%) at an α = 0.05. The self-cured specimens resulted in significantly lower HM and DC% values from the dual-cured group, as expected. However, in the presence of the adhesives with touch-cure activators, the conversion of the self-cured groups showed insignificant differences in HM and DC% from the dual-cured in both composite materials. The improvements on the bottom composite surfaces in contact with the adhesives did not extend to the entire specimen length. Nevertheless, improved interfacial curing may improve interfacial durability.

Self-Etch Silane Primer: Reactivity and Bonding with a Lithium Disilicate Ceramic.

The aim of the study was to evaluate the stability, reactivity, and bond strength with a lithium disilicate ceramic of a self-etch silane primer (Monobond Etch and Prime/MEP). The stability was evaluated by 1H-,31P-NMR spectroscopy (before/after aging), and the reactivity by micro MIR-FTIR spectroscopy on Ge surfaces (0, 1, 24 h) using a prehydrolyzed silane primer (Calibra Silane Coupling Agent/CLB), as a control. The effect of MEP vs. 5% HF-etching on ceramic roughness was assessed by optical profilometry. The shear bond strength (SBS) of a resin composite bonded to polished ceramic surfaces treated with MEP, HF without silane (HF+NS), HF+CLB, and HF+MEP (n = 20) was evaluated after storage in water (A: 37 °C/1 week, B: 5000×/5-55 °C and C: 100 °C/24 h). Aging did not affect the silanol groups of MEP, but only the phosphate co-monomer. Silanols were reactive forming siloxanes, but exhibited lower consumption rate than CLB. HF-etching induced significantly higher values than MEP, in all the roughness parameters tested (Sa, Sz, Sdr, Sc, Sv), with the greatest differences found in Sdr and Sv. For SBS, MEP was inferior to all treatments/storage conditions, except of HF+NS in A, where the values were similar. However, on a HF-etched substrate, MEP provided highest strength and reliability.

Reactivity and Bond Strength of Universal Dental Adhesives with Co-Cr Alloy and Zirconia.

The aim of this study was to evaluate (a) the reactivity of six universal dental adhesives with polished cobalt-chrome (Co-Cr) alloy and zirconia (3Y-TZP) surfaces; and (b) to assess the shear bond strength (SBS) of a resin composite with polished and alumina-blasted surfaces as mediated by these adhesives. The products tested were Adhese Universal (AD), All-Bond Universal (AB), Clearfill Universal Bond (CB), G-Premio Bond (GP), Prelude One (PO) and Scotchbond Universal (SB). The reactivity on polished substrates was evaluated by reflection infrared microscopy (RFTIRM). The roughness parameters of polished and 50 µm alumina grit-blasted surfaces were assessed by optical profilometry. The SBS of the composite bonded to the substrates treated with each adhesive (n = 10/product) was evaluated after 1 week of storage (H2O/37 °C) by Weibull statistics. Evidence of phosphate interaction with polished substrates was obtained by FTIRM, with higher peaks on the alloy. Alumina-blasting increased all roughness parameters with higher values on the alloy. AD, CB were the strongest (σ0) treatments on alloy surfaces and AD, CB, AB, SB on zirconia. GP was the weakest on both substrates and the least reliable (ß) on alloy. On polished alloy GP, PO performed better (σ0), whereas on zirconia there were no significant differences. All adhesives showed more prominent reaction with the Co-Cr alloy than with 3Y-TZP.

Silane reactivity and resin bond strength to lithium disilicate ceramic surfaces.

OBJECTIVE: To evaluate the silane status in commercially available products and their bonding capacity with polished glass-ceramic surfaces before and after hydrofluoric (HF) acid-etching. METHODS: The products tested were Calibra Silane Coupling Agent/CS, G-Multi Primer/GM, Kerr Silane Primer/KS, Monobond Plus/MB and Scotchbond Universal Adhesive/SB. The silane status was studied by 13C nuclear magnetic resonance spectroscopy (13C-NMR). The roughness parameters of polished (group A) and HF acid-etched (group B) lithium disilicate glass-ceramic surfaces were measured by optical profilometry (n = 5/group). The interaction of the products with group A and B ceramic surfaces was examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The shear strength (SBS) of a flowable composite bonded to the ceramic surfaces (groups A, B) was assessed before (NS) and after silane treatment (n = 20/group, product). RESULTS: The NMR analysis showed the presence of silanol monomers only in CS. Methoxylated-siloxane adducts were found in GM, silanol-siloxane adducts in MB, SB, and siloxane polymers in KS. Acid-etching greatly increased Sa, Sz, Sdr, Sc and Sv parameters (p < 0.001) and ATR-FTIR analysis demonstrated evidence of bonding with the substrate in CS. Weibull analysis of SBS revealed the following rankings in characteristic life (p < 0.05): CS > SB,KS,MB > GM > NS (group A) and CS > GM > SB,KS,MB,NS (group B). The most reliable treatment in both groups was CS. For the same silane treatment, the SBS of group B were significantly higher from group A. Failures were mainly of adhesive type, except of several partial resin cohesive failures found in group B. SIGNIFICANCE: The chemical bonding capacity of the silanes was highest in products with silanol monomers. Acid-etching increased bond strength to a level that neutralized the silane contribution in products with silanol-siloxane adducts and siloxane polymers, providing thus bond strength values similar to silane-free treatments.

Universal Adhesives: Setting Characteristics and Reactivity with Dentin.

The aim of the study was to evaluate the performance of six commercially available universal dental adhesives: Adhese Universal (ADU), All-Bond Universal (ABU), Clearfil Universal Bond Quick (CBQ), G-Premio Bond (GPB), Prelude One (PRO) and Scotchbond Universal (SBU). The properties tested were: (a) degree of C=C conversion (DC%); (b) Vickers micro-hardness (VHN); (c) extent of oxygen inhibition (OI/µm), all related with the adhesive film properties; (d) extent of dentin demineralisation (DM%), insoluble salt formation (AS%); and (e) shear bond strength (SBS, self-etch mode) related to the adhesive-dentin interactions. Statistical analysis (α = 0.05) was performed by one-way ANOVA and Tukey's test (DC%, VHN, OI, DM% AS%) and Weibull analysis (SBS, σ0-ß). The DC ranged from 67.2-82.5% (all >GPB), OI from 5.6-18.6 µm (SBU > ADU, GPB, ABU > CBQ > PRO), microhardness from 1.1-6.6 VHN (SBU > ADU > ABU > CBQ > PRO > GPB: not measurable), DM from 69.3% (GPB) to 16-12.5% (CBQ, SBU, ADU) and 13.2-10.6% (ABU, ADU, PRO), in homogeneous groups and AS from 26-15.9% (ABU, CBQ > GPB, PRO, ADU, SBU). For SBS the σ0 (characteristic life) ranged from 29.3-16.6 MPa (CBQ, ADU, ABU, SBU > PRO > GPB), the ß (reliability) from 5.1-9.7 (p > 0.05). All failure modes were of mixed type (adhesive and composite cohesive). Although all these adhesives were based on the 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) adhesive monomer, the different co-monomers, solvents and catalysts led to variations in their film properties, reactivity and bonding capacity with dentin.

Alexithymia components in excessive internet users: a multi-factorial analysis.

The increasing use of computers and the internet - especially among young people - apart from its positive effects, sometimes leads to excessive and pathological use. The present study examined the relationship among the excessive use of the internet by university students, the alexithymia components and sociodemographic factors associated with internet users and their online activities. 515 university students from the University of Thessaly participated in the study. Participants anonymously completed: a) the Internet Addiction Test (IAT), b) the Toronto Alexithymia Test (TAS 20) and c) a questionnaire covering various aspects of internet use and demographic characteristics of internet users. Excessive use of the internet among Greek university students was studied within a multi-factorial context and was associated with the alexithymia and demographic factors in nonlinear correlations, forming thus a personalized emotional and demographic profile of the excessive internet users.

Personality characteristics and profiles of Greek elementary teachers using the sixteen personality factor questionnaire (16PF).

Empirical evidence indicates that a teacher's personality influences the classroom climate, students' behaviors, and their interpersonal relationships. Although the effect of a teacher's personality on students' psychological well-being has long been stressed in many studies, very little is known about the actual personality characteristics of Greek in-service teachers. The purpose of this study was to allocate the characteristics that best describe the personality of Greek elementary school teachers (according to the 16 Cattellian primary factors). Our study belongs in the broader research field aiming at describing and understanding the possible foundations of teachers' behavior. The sample consisted of 138 elementary teachers, who completed a standardized Greek version of the 16PF. Our statistical analysis of one-sample t-test along with an effect size calculation revealed that certain personality characteristics described the Greek elementary teacher and clearly distinguishes them from the normative group of the Greek population. Elementary teachers appear to be quite submissive, cautious, with a tendency to oppose or postpone change. They also scored a low tolerance level against fear and arousal, and high tension levels. Elementary teachers seem to respond to events, ideas, and experiences more with feeling than with thinking and find it difficult to control their feelings, which results in getting upset easily. They also seem to pay little attention to how they may appear to others and generally do what they feel like doing. Elementary teachers also scored low on aspiration level. Possible implications of the results are discussed with reference to students' psychological well-being.

The stigmatization of obesity in children. A survey in Greek elementary schools.

This study investigates elementary school children's prejudice towards obesity. A sample of 1861 underweight, normal, overweight and obese children from Central Greece were instructed to rank 6 drawings of same sex children with various physical disabilities, obesity or no disability at all ("healthy"), according to how much they liked each child. Results showed that all participants ranked the obese child last, showing that even obese individuals show negative attitudes towards obesity. Gender differences were recorded in almost all the drawings. Girls liked obese children and those with facial disfigurement less than boys did while boys disliked children with physical disabilities more than girls.

Parental bonding and depression: personality as a mediating factor.

UNLABELLED: According to Bowlby's theory of attachment, the role of early experience and parenting is of crucial importance to child development and mental health. In addition, several research findings suggest that parental bonding and different types of attachment play a crucial role in personality development. The present study examines the association between parental bonding experiences (lack of parental care, overprotection or both) and depression during adulthood. The objective of the present study was to evaluate different personality dimensions as possible mediators of the relation between perceptions of parental bonding and depressive symptoms in adult life. METHODS: 181 participants (15- 49-years-old) completed the Parental Bonding Instrument (PBI), the Beck Depression Inventory (BDI) and the 16 Personality Factor Questionnaire (16PF). RESULTS: The results show that lack of parental care and overprotection is linked with depressive symptoms and a number of personality characteristics, such as low self-esteem, introversion, distress and emotional instability. In contrast, high care and low protection (optimal bonding) is linked with increased self-confidence, less distress and less depressive symptoms. CONCLUSIONS: The results presented here are in line with Bowlby's theory of attachment and show that parental bonding is linked with problematic personality development and psychopathology. The present study provided evidence that personality factors may mediate the observed relationship between parental rearing style and depression. The potential causal mechanisms warrant longitudinal evaluation.

Relation of self-concept in kindergarten and first grade to school adjustment.

The present aim was to investigate changes in self-concept and self-concept stability during children's transition from kindergarten to primary school, and the relationship between children's self-concept and their adjustment to elementary school. 346 children took part in this 2-yr. longitudinal study. The Pictorial Scale of Perceived Competence and Social Acceptance for Young Children was used to assess children's self-concept. Children's school adjustment was assessed using the schools' academic, behavioral, and social-emotional procedures. Children's self-concept appeared relatively stable and the decline in scores appeared to be practically unimportant. Analysis showed that children's school adjustment mainly affects the academic dimension of self-concept.

Qualitative analysis of experiences of members of a psychoeducational assertiveness group.

This study describes qualitatively a psychoeducational assertiveness intervention for 20 women's perceptions of positive and negative experiences, undertaken to identify whether therapeutic mechanisms operating in group therapy as described by Yalom might be inferred. There were 14 90-min. weekly sessions organized around educational material. Two groups were conducted with 10 university women each (M= 20.9 yr., SD= 1.9). Qualitative analysis of the 20 interviews identified five of Yalom's therapeutic mechanisms, namely, self-understanding, universality, acceptance, catharsis, and self-disclosure. The positive experiences were group cohesiveness, self-understanding, self-disclosure, positive views about the self and learning, and cognitive benefits. Self-disclosing at the early stages of group development was the most frequently reported negative experience or difficulty in the group. Although participants stated they improved interpersonal communication skills, analysis suggested the cultural context was an important mediator of assertive behavior.

Laying the foundations of well being: a creative psycho-educational program for young children.

Dysfunctional cognitive schemata and pessimistic explanatory styles are usually held responsible for some of the commonest features of depressed mood such as feelings of meaninglessness, resignation, and underachievement which seem to affect even young children. This pilot study investigates the applicability and efficacy of an interactive, creative psycho-educational program for preschoolers that aims at enhancing mastery and shaping optimistic explanatory styles. Twenty preschoolers participated in once-a-week hourly sessions which took place in their school and lasted for one school year. The intervention consisted of several playful tasks and novel creative activities specially designed to meet the needs and abilities of preschoolers, while satisfying the objectives of the school curriculum. The tasks were based on the principles of cognitive behaviour theory. Qualitative and quantitative analyses of our results support the efficacy of the intervention for preschoolers.

A cognitive-behavioral intervention program for students with special reading disabilities.

Interaction among cognitive, meta-cognitive, and emotional factors seems to play a determining part in achievement behavior and especially in scholastic performance. In this study some preliminary results are presented of the implementation of a multidimensional cognitive-behavioral psychoeducational program especially designed for students with reading disabilities in which parents and teachers also take part. The aim of the program was to provide students with appropriate emotional and cognitive skills with which to address their learning problems. First results on the efficacy of the implemented program to 20 primary school boys and girls with special reading disabilities encourage research on management of learning problems with focus on cognitive and emotional aspects in which parents and teachers contribute. Research including a control group is necessary.

DNA damage and repair efficiency in lymphocytes from schizophrenic patients.

In the present study we examined schizophrenic patients' lymphocytes sensitivity to the effects of external factors, such as hydrogen peroxide and gamma-irradiation and also their repair efficiency with the comet assay. Our results did no show any difference in basal levels of DNA damage between schizophrenic and normal populations. The slightly increased sensitivity of the schizophrenic population to the externally induced DNA damage compared to controls was not statistically significant. Also the small reduction in the DNA repair efficiency in schizophrenics in comparison to normal population was found to be not statistically significant. Finally, patients with heritable predisposition to schizophrenia did not show any difference in their response from the other schizophrenics.

Visuomotor coordination and visuospatial working memory of children with specific reading disabilities: a study using the Rey-Osterrieth Complex Figure.

The aim of the present study was to examine the visuospatial perception, short-term working memory, and motor skills of children with special reading difficulties, using the Rey-Osterrieth Complex Figure, which can record visuomotor and memory skills, observe drawing processes, and detect deficiencies in specific skills. 306 right- and left-handed boys and girls, ages 6.6 to 9.6 yr. (102 with special reading difficulties, 102 normal readers, and 102 with general learning difficulties) comprised one experimental and two control groups, respectively. The task was to depict the Rey-Osterrieth Complex Figure under two conditions, copying and drawing it from memory. Analysis indicated that (a) difficulty of the depiction of the Rey-Osterrieth Complex Figure, especially from memory, sharply affects children's performance and (b) the experimental group's performance was significantly poorer than that of controls in both conditions. The results are discussed in view of the predictive value of certain motor and cognitive skill deficiencies of children with special reading difficulties.

DNA damage in a human population affected by chronic psychogenic stress.

The effects of chronic psychogenic stress on the expression of DNA damage and cellular response to the damage were investigated. Using the comet assay, basal DNA damage was found to be similar in lymphocytes of both affected and non-affected populations (n = 30 in both groups). The induction of DNA damage in lymphocytes by external factors (H2O2 and gamma-irradiation), was also investigated. In these studies, cells were treated with 50, 100 and 150 microM H2O2 for 5 minutes or with 0.8, 2.5 and 4.2 Gy gamma-rays. A significant difference was found between the chronically stressed and the control populations, indicating the enhanced sensitivity of the former population. Cells were also held for 2 hours after the treatment, allowing time for the cells to deal with the induced DNA damage. Based on the level of residual DNA strand breaks, cells from the stressed population had more breaks than the controls. Gender does not alter these findings. In conclusion, our data indicate that cells from the stressed population were more sensitive to the induction of DNA damage and had higher level of residual damage. Therefore, stress conditions may cause the affected individuals to be susceptible to environmental mutagenic agents.