When the fear of dentist is relevant for more than one's oral health. A structural equation model of dental fear, self-esteem, oral-health-related well-being, and general well-being.

PURPOSE: To develop and test a complex model that captures the individuals' general well-being and the specific oral-health-related well-being. We were specifically interested, as a specific research question, if self-esteem, dental fear, and the oral health-related well-being are credible predictors for the general well-being. PATIENTS AND METHODS: A one-time associative research design measured dental-specific anxiety, self-esteem, oral-health-related specific well-being, and general well-being in 281 participants, 3rd and 6th year dental students (M Age =22.59 years, SD Age =3.13; 55% females), which completed a battery of relevant questionnaires: the Dental Fear Survey, the Rosenberg Self-Image Scale, the short form of Oral Health Impact Profile, and the Flourishing Scale. The data were subject to structural equation modeling in order to validate potential pathways of influence hypothesized based on previous evidence from the literature. RESULTS: We developed and tested a complex structural equations model, in which dental fear influences both the specific oral-health-related well-being and the persons' self-esteem. In turn, self-esteem mediates the influence pathways between dental fear and oral-health-specific well-being, on the one hand, and the overall well-being, on the other hand. CONCLUSION: Our research contributes directly to strengthening the theoretical basis for future interdisciplinary research, by providing, first, a tested and replicable model that surpasses the simple correlation or prediction, and second, empirical evidence for the significant mutual interdependence between psychological experiences, eg, self-esteem, and the two main aspects of well-being, ie, specific and general. From a practical, clinical viewpoint, our research provides further insights and justification for the importance of educating the patient, on all levels, from the individual clinical practice to community programs and public oral health policies, with respect to the importance of oral health.

Complex interrelations between self-reported oral health attitudes and behaviors, the oral health status, and oral health-related quality of life.

PURPOSE: The purpose of this study was to develop and test a moderated mediation model that was able to describe the relationships between oral health-related attitudes and behaviors, oral health status (OHS), and oral health-related quality of life. The hypothesized relations corresponded to research questions such as "is a person's oral health predicted by the actions that person takes in order to prevent oral health conditions?" and "do individuals with better oral health also have higher levels of oral health-related quality of life?". MATERIALS AND METHODS: A cross-sectional correlational study with selected predictor variables was conducted in Cluj-Napoca, Romania, among 191 participants, enrolled in the fourth and sixth years of study at the Dentistry School of the Medicine and Pharmacology, University of Cluj-Napoca. Participants completed the Hiroshima University Dental Behavior Inventory (HUDBI) questionnaire targeting specific behavior and attitude with respect to their dental self-care, Oral Health Impact Profile (OHIP) short questionnaire for measuring oral health-related quality of life, and the current OHS was assessed objectively using Decayed, Missing, Filled Teeth/Surfaces (DMFT) index. Statistical analyses were done using structural equation modeling software. RESULTS: Our research showed relevant associations between HUDBI, DMFT, and OHIP. The relationship between HUDBI and OHIP was mediated by DMFT. Furthermore, HUDBI worked as a moderator between DMFT and OHIP. Thus, our study revealed a case for moderated mediation, which is usually ignored in similar research. CONCLUSION: The "straightforward" causality between oral health-related behavior and the actual OHS must be considered with caution, as well as their impact on the oral health-related quality of life. Further research is needed to investigate the interaction between variables, the strength of the interrelations and the magnitude of their interactions, and the confidence that can be placed in these measurements, with respect to the general population and/or those lacking domain-specific education.

Optimization and Entropy Production: Application to Carnot-Like Refrigeration Machines.

Several optimization models of irreversible reverse cycle machines have been developed based on different optimization criteria in the literature, most of them using linear heat transfer laws at the source and sink. This raises the issue how close to actual operation conditions they are, since the heat transfer law on the phase-change processes is dependent on ΔT3. This paper addresses this issue by proposing a general model for study and optimization of thermal machines with two heat reservoirs applied to a Carnot-like refrigerator, with non-linear heat transfer laws and internal and external irreversibility. The optimization was performed using First and Second Law of Thermodynamics and the Lagrange multipliers method. Thus, several constraints were imposed to the system, also different objective functions were considered, allowing finding the optimum operating conditions, as well as the limited variation ranges of the system parameters. Results show that the nature of the heat transfer laws affects the optimum values of system parameters for obtaining maximum performances and also their magnitude. Sensitivity studies with respect to system several parameters are presented. The results contribute to the understanding of the system limits in operation under different constraints and allow choosing the most convenient variables in given circumstances.