Enhancing Intraoral Fluoride Retention in Older Adults: A Randomized Crossover Study.

INTRODUCTION: Previous studies have shown that a calcium prerinse can increase intraoral fluoride retention from a fluoride rinse. To explore the potential of this approach to control root caries, we assessed intraoral fluoride bioavailability after a calcium prerinse in older adults with normal to low salivary flow rates. METHODS: In a 2-period crossover trial (NCT04239872), 20 participants (65-80 y old), with low or normal salivary flow rate, rinsed for 1 min with a 0.05% NaF mouth rinse (226 ppm F, F only) or with this rinse immediately after a 1-min rinse with 150 mM calcium lactate (Ca→F). Dental biofilm and saliva samples were collected before and up to 2 h after the rinse(s). Fluoride concentrations in saliva (whole and clarified) and dental biofilm (fluid and solid phases) were blindly determined. Data were statistically analyzed by a mixed-effects model for the effect of treatment, time, and their interaction (α = 5%). RESULTS: The Ca→F group resulted in significantly higher fluoride concentrations in all variables analyzed, for almost all of the collection time points. The effect was greater in the biofilm solids and whole saliva (compatible with the formation of calcium fluoride deposits) and still significant (P < 0.001) after 2 h in the biofilm fluid and clarified saliva, suggesting that fluoride stored in insoluble particles was released, increasing free fluoride. CONCLUSION: The use of a calcium prerinse before a fluoride rinse was able to prolong intraoral fluoride bioavailability in older adults. KNOWLEDGE TRANSFER STATEMENT: A calcium prerinse increased intraoral fluoride bioavailability in older individuals. This approach could be used to improve root caries control without the need to increase the fluoride concentration in dental products.

Loss of idealism or realistic optimism? A cross-sectional analysis of dental hygiene students' and registered dental hygienists' professional identity perceptions.

OBJECTIVES: The dental hygiene profession in the U.S. is in the process of establishing a direct access model of care and contributing to the creation of the profession of a dental therapist. The objectives were to analyse the professional role perceptions of dental hygiene students and registered dental hygienists in these times of change. Specifically, it was explored whether dental hygiene students' current professional identities differ (i) from their expected future identities, and (ii) from dental hygienists' current and (iii) past identities. METHODS: Survey data were collected from 215 dental hygiene students concerning their present and future role perceptions, and from 352 registered dental hygienists concerning their present and past professional identity perceptions. RESULTS: Students' future professional identity perceptions were even more positive than their very positive current perceptions of their professional role components. Students' current perceptions of professional pride, professional ambition, work ethic and patient relations were more positive than dental hygienists' current perceptions of these professional role components. A comparison of students' current perceptions with dental hygienists' current and retrospective descriptions showed that students were more positive than dental hygienists in each case. CONCLUSIONS: The fact that dental hygienists had less positive role perceptions than dental hygiene students might lead to the conclusion that a loss of idealism occurs over the course of a professional lifespan. However, dental hygienists actually improved their role perceptions over time and students' future descriptions were more positive than their current descriptions, supporting the interpretation that realistic optimism dominates professional role perceptions in these times of change.

Mechanical strain delivers anti-apoptotic and proliferative signals to gingival fibroblasts.

Physical forces play a critical role in the survival and proliferation of many cell types, including fibroblasts. Gingival fibroblasts are exposed to mechanical stress during mastication, orthodontic tooth movement, and wound healing following periodontal surgery. The aim of this study was to examine the effect of mechanical strain on human gingival fibroblasts (hGF). Cells were subjected to short-term (up to 60 min) and long-term (up to 48 hrs) 20% average elongation at 0.1 Hz. We monitored survival signaling by evaluating the phosphorylation status and localization of Forkhead box (FoxO) family members, which are mediators of apoptosis. We also examined strain-induced proliferation by measuring the level of proliferating cell nuclear antigen (PCNA). We observed that cyclic strain caused the phosphorylation and retention in the cytoplasm of FoxO family members. Moreover, mechanical strain resulted in increased ERK kinase phosphorylation and PCNA expression. In conclusion, cyclic strain delivers anti-apoptotic and proliferative stimuli to hGF.

Caveolin-enriched membrane signaling complexes in human and murine osteoblasts.

Osteoblasts receive regulatory signals from hormones, growth factors, calcium, extracellular matrix, and other cells through a variety of receptors that utilize an array of signaling pathways and cytoplasmic messengers. This article addresses the nonuniform distribution of important signaling molecules (platelet-derived growth factor receptors [PDGFRs], nonreceptor tyrosine kinases, tyrosine kinase adaptor proteins, G proteins, and nitric oxide synthases [NOSs]) in the surface membranes of human and murine osteoblasts. We show that particular inner leaflet signaling molecules (e.g., heterotrimeric G proteins and Src family tyrosine kinases) are clustered and concentrated in Triton X-100-insoluble membranes that are enriched in caveolin, the major structural component of caveolae (50- to 100-nm flask-shaped invaginations of the plasma membrane that apparently are organized by oligomers of the protein caveolin). In addition, we show that a subset of highly ligand-responsive PDGFRs and mitogen-activated protein (MAP) kinase pathway effectors are present in the caveolin-enriched membrane fraction of osteoblasts.