La evaluación de la resistencia al cizallamiento del cemento de ionómero de vidrio modificado con resina con la adición de vidrio bioactivo 45S5 utilizando dos métodos convencionales.

Introduction: There is a high prevalence of enamel caries around brackets due to the young age of the majority of orthodontic patients, and to the difficulty of plaque removal in presence of orthodontic appliances. Recently, protective agents such as bioactive glasses (BGs) were introduced to enhance remineralization and prevent demineralization of tooth structures.  This study aimed to assess the shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) with addition of 45S5 BG to enhance its remineralizing potential using two conventional methods. Material and methods: This in-vitro experimental study evaluated three groups (n=20) of orthodontic brackets bonded to enamel using Transbond XT (group 1), light-cure RMGIC (group 2) and RMGIC with BG added (group 3). Samples underwent 7000 thermal cycles and their SBS was measured. The adhesive remnant index (ARI) score was also determined. Quantitative data were analyzed using one-way ANOVA while qualitative data were analyzed using a chi-square test. Discussion: The results showed no significant difference in SBS between study groups, however the ARI scores were significantly different among the groups. The RMGIC group showed the highest ARI while RMGIC doped with BG showed the lowest ARI score. Conclusion: Addition of 30% w/v 45S5 BG to RMGIC does not cause a significant change in SBS of orthodontic brackets bonded to enamel, while resulting in less amount of luting agent remnants on the enamel surface after debonding. Introducción: Existe una alta prevalencia de caries del esmalte alrededor de los brackets debido a la corta edad de la mayoría de los pacientes de ortodoncia y a la dificultad de remoción de la placa en presencia de aparatos de ortodoncia. Recientemente, se introdujeron agentes protectores como los vidrios bioactivos (VB) para mejorar la remineralización y prevenir la desmineralización de las estructuras dentales. Este estudio tuvo como objetivo evaluar la resistencia al cizallamiento (RC) del cemento de ionómero de vidrio modificado con resina (CIVMR) con la adición de 45S5 BG para mejorar su potencial remineralizante utilizando dos métodos convencionales. Material y Métodos: Este estudio expe-rimental in vitro evaluó tres grupos (n = 20) de brackets de ortodoncia adheridos al esmalte usando Transbond XT (grupo 1), CIVMR fotopolimerizable (grupo 2) y CIVMR con VB agregado (grupo 3). Las muestras se sometieron a 7000 ciclos térmicos y se midió su RC. También se determinó la puntuación del índice de restos de adhesivo (IRA). Los datos cuantitativos se analizaron mediante ANOVA de una vía, mientras que los datos cualitativos se analizaron mediante una prueba de chi-cuadrado. Discusión: Los resultados no mostraron diferencias significativas en la RC entre los grupos de estudio, sin embargo, los puntajes IRA fueron significativamente diferentes entre los grupos. El grupo CIVMR mostró el ARI más alto mientras que CIVMR dopado con VB mostró el puntaje IRA más bajo. Conclusión: La adición de un 30% p/v de 45S5 VB a CIVMR no causa un cambio significativo en la RC de los brackets de ortodoncia adheridos al esmalte, mientras que resulta en una menor cantidad de remanentes de agente de fijación en la superficie del esmalte después del desprendimiento. Resistencia al Corte

The evaluation of shear bond strength of resin-modified glass ionomer cement with the addition of 45S5 bioactive glass using two conventional methods.

Introduction: There is a high prevalence of enamel caries around brackets due to the young age of the majority of orthodontic patients, and to the difficulty of plaque removal in presence of orthodontic appliances. Recently, protective agents such as bioactive glasses (BGs) were introduced to enhance remineralization and prevent demineralization of tooth structures.  This study aimed to assess the shear bond strength (SBS) of resin-modified glass ionomer cement (RMGIC) with addition of 45S5 BG to enhance its remineralizing potential using two conventional methods. Material and methods: This in-vitro experimental study evaluated three groups (n=20) of orthodontic brackets bonded to enamel using Transbond XT (group 1), light-cure RMGIC (group 2) and RMGIC with BG added (group 3). Samples underwent 7000 thermal cycles and their SBS was measured. The adhesive remnant index (ARI) score was also determined. Quantitative data were analyzed using one-way ANOVA while qualitative data were analyzed using a chi-square test. Discussion: The results showed no significant difference in SBS between study groups, however the ARI scores were significantly different among the groups. The RMGIC group showed the highest ARI while RMGIC doped with BG showed the lowest ARI score. Conclusion: Addition of 30% w/v 45S5 BG to RMGIC does not cause a significant change in SBS of orthodontic brackets bonded to enamel, while resulting in less amount of luting agent remnants on the enamel surface after debonding. Introducción: Existe una alta prevalencia de caries del esmalte alrededor de los brackets debido a la corta edad de la mayoría de los pacientes de ortodoncia y a la dificultad de remoción de la placa en presencia de aparatos de ortodoncia. Recientemente, se introdujeron agentes protectores como los vidrios bioactivos (VB) para mejorar la remineralización y prevenir la desmineralización de las estructuras dentales. Este estudio tuvo como objetivo evaluar la resistencia al cizallamiento (RC) del cemento de ionómero de vidrio modificado con resina (CIVMR) con la adición de 45S5 BG para mejorar su potencial remineralizante utilizando dos métodos convencionales. Material y Métodos: Este estudio expe-rimental in vitro evaluó tres grupos (n = 20) de brackets de ortodoncia adheridos al esmalte usando Transbond XT (grupo 1), CIVMR fotopolimerizable (grupo 2) y CIVMR con VB agregado (grupo 3). Las muestras se sometieron a 7000 ciclos térmicos y se midió su RC. También se determinó la puntuación del índice de restos de adhesivo (IRA). Los datos cuantitativos se analizaron mediante ANOVA de una vía, mientras que los datos cualitativos se analizaron mediante una prueba de chi-cuadrado. Discusión: Los resultados no mostraron diferencias significativas en la RC entre los grupos de estudio, sin embargo, los puntajes IRA fueron significativamente diferentes entre los grupos. El grupo CIVMR mostró el ARI más alto mientras que CIVMR dopado con VB mostró el puntaje IRA más bajo. Conclusión: La adición de un 30% p/v de 45S5 VB a CIVMR no causa un cambio significativo en la RC de los brackets de ortodoncia adheridos al esmalte, mientras que resulta en una menor cantidad de remanentes de agente de fijación en la superficie del esmalte después del desprendimiento. Resistencia al Corte

Examining the Impact of Motivation on Working Memory Training in Youth with ADHD

Background: Working memory (WM), the ability to temporarily store and manipulate information, has been noted as a deficit in children with attention deficit hyperactivity disorder (ADHD) and may be causally related to other cognitive impairments in this clinical population. Cogmed, a computerized WM training program, appears to yield WM improvements although claims of transfer to other domains such as academic achievement are not widely supported by research. Individual differences such as motivation have been suggested as mediating factors, though motivation has not been directly assessed in studies of Cogmed to date. Objective: The overall objective was to examine motivational influences on ADHD youths’ experience with Cogmed using complementary quantitative and qualitative approaches. Aim 1 examined whether individual differences in motivational styles were correlated with a metric of training engagement and scores on transfer outcomes. Aim 2 explored youth’s self-reported motivation and subjective experience from a post-intervention interview. Methods: Data were collected as part of a larger study contrasting a modified Cogmed protocol (n = 20) with physician-monitored standard of care (n = 20) in a community sample of rigorously diagnosed ADHD youth 8 – 14 years of age. Youth in both groups completed comprehensive assessments at baseline, post-intervention (post 1), and again 3 months afterward (post 2). The current study focuses on 10 ADHD youth randomized to the modified Cogmed group who also completed an adapted Self-Regulation Questionnaire (SRQ) and participated in a semi-structured motivational interview at the post 2 follow-up. Results: The subset of ADHD youth who were the focus of this study (n = 10) did not differ on demographic, clinical characteristics, or baseline measures when compared with ADHD youth who were randomized to the modified Cogmed group prior to inclusion of the SRQ and motivational questionnaire (n = 10). In our subset of ADHD youth, all showed perfect adherence to the modified Cogmed protocol. Youth who were more externally motivated started modified Cogmed training at a higher level of performance and also reached higher peak performance during the intervention program. At follow-up, higher levels of external motivation also predicted better spatial working memory and lower self-concept, whereas higher levels of introjected/identified motivation predicted worse academic performance. Qualitative analyses suggested that youth displayed flexible motivation with regard to their participation in modified Cogmed training and perceived subjective improvements in their everyday life function. Conclusions: ADHD youth endorsed multiple types of motivation when motivation was assessed using quantitative and qualitative approaches and reported that modified Cogmed training was useful. Higher external motivation demonstrated a more robust association with modified Cogmed training engagement and better scores on select outcome measures compared with other motivational styles

Goal-Striving and Pilot Goal Management Training in Adolescents with Attention-Deficit/Hyperactivity Disorder

Goal-striving across academic, social, and psychological domains of life is associated with many positive outcomes. Unsuccessful goal pursuits increase the risk of engagement in health-risk behaviours, future vocational difficulties, and interpersonal challenges. Individuals with ADHD have difficulties in academic and interpersonal areas of life, with well-documented motivational and executive functioning (EF) challenges. Stimulant medications, the most used treatment for ADHD, do not target these challenges and few interventions offered to adolescents with ADHD appear to support goal-striving. Although research investigating motivational and EF difficulties in ADHD has determined that support is necessary for successful goal-pursuit, little is known about how motivation, EF, and other factors such as grit (i.e., task persistence) impact efforts made by adolescents with ADHD to work on their goals. The current dissertation focuses on the EF deficits and motivational insight of adolescents with ADHD, in service of best supporting youth in both everyday contexts and interventions. The work presented in Studies 1 - 3 sought to present a fulsome description of how goal-striving difficulties lead to the functional impairments noted in adolescents with ADHD (i.e., ineffective goal-striving), by describing the motivation and EF of adolescents with ADHD compared to their same-aged peers and emerging adults in university. The sample included adolescents aged 14 – 17 years with and without ADHD, as well as emerging adults aged 19 – 22 years; each group was approximately 50% female. Study 1 highlighted that adolescents, as compared with their emerging adult peers, appear to require more effort and support to work on their goals. However, adolescents with ADHD also endorse less interest towards their academic goals, demonstrate difficulty linking their immediate goals to their future ambitions, and do not apply flexibility to their goal-pursuit strategies. In Study 2, adolescents with ADHD endorsed significantly more EF challenges and less grit compared to their peers, suggesting that support for adolescents with ADHD must uniquely address these challenges. For all adolescents, more external motivation was associated with higher levels of EF challenge. When considering motivation across any kind of goal (i.e., academic and non-academic), adolescents with ADHD demonstrated both internal and external motivational styles. This may indicate that adolescents with ADHD demonstrate nuances in their motivation not captured in previous studies, such that they are not simply “less motivated” than their peers, but rather that their EF difficulties may lead to less internal motivation towards academic goals. Building upon this, Study 4 outlined how these groups regulate their motivation by attempting to create a fit between their motivational state and task strategies, an ability known as metamotivation. Generally, all groups reported their experiences of both high and low motivational states (e.g., interest, meaningfulness, boredom, frustration), and strategies that bolster their goal striving in response to those feelings. However, there was variability in the metamotivational insight held by participants, such that those with ADHD tended to have a harder time recognizing feelings of low motivation and strategizing for conflict between complex goals. Results from these studies supported the need for a goal-striving intervention targeted for adolescents with ADHD, for whom EF difficulties and motivational awareness appear to create barriers to their goals. The final study of this dissertation piloted a modified Goal Management Training intervention for adolescents with ADHD, providing preliminary evidence of the feasibility of this EF intervention. Six participants (Mage = 15 years, SD = 1.1; 2 females; 66% taking stimulant medication for ADHD management) demonstrated adherence and tolerance to the training, and for some participants there was reliable change in self-reported executive functioning, functional impairment, and tasks of inhibition/switching, as well as parent-rated executive functioning. All parents reported improvements in their adolescent’s functional impairment. All but two participants met the goal they had selected prior to training. Results show that further exploration of the benefits and effects of training is warranted, showing the potential for a goal-based intervention as a new direction for treatment of difficulties associated with ADHD. Overall, the studies presented in this dissertation demonstrate the possibility of integration various social and clinical psychological constructs and provides a framework for future larger-scale studies