Dynamic dentin: A quantitative microscopic assessment of age and spatial changes to matrix architecture, peritubular dentin, and collagens types I and III.

To investigate age and site-related changes to human dentin collagen, sound human teeth collected from donors aged 13-29 (young) and 50-74 (aged) years (n = 9/group) were cut to shallow and deep sites. Dentin collagen orientation and fibril bundling was investigated using the Picrosirius Red (PSR) stain observed under cross-polarized light microscopy (Pol), and collagen distribution was investigated using Confocal Laser Scanning Microscopy (CLSM). Collagen types III to I distribution in peritubular dentin (PTD) was revealed using Herovici stain and brightfield microscopy. Image analysis software and linear mixed modelling quantified outcomes. In situ dentin collagen was observed using Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM). The PSR-Pol analysis revealed less coherently aligned and more bundled collagen fibrils in aged dentin (P = 0.005). Deep inner dentin collagen in both groups were less coherently aligned with reduced bundling. Regardless of age, CLSM showed collagen distribution remained stable; and more collagen type III was detectable in PTD located in inner dentin (Young: P = 0.006; Aged: P = 0.008). Observations following Xe PFIB-SEM cross-sectioning showed apatite-like deposits surrounding large intratubular collagen fibers, and evidence of smaller intertubular dentin collagen fibrils in situ. In conclusion, aging changes collagen network architecture, but not distribution or content.

A culture shock in dental hygiene: Exploring the management of oral health after head and neck cancer.

OBJECTIVES: Managing oral health after the treatment for head and neck cancer requires meticulous daily oral hygiene practices and regular professional dental care; however, the individual factors and health system structures required to achieve oral health are often not well considered. This study aimed to explore how oral health was understood and managed after head and neck cancer treatment and identify factors that influenced oral health behaviours and dental service utilization. METHODS: A qualitative, inductive approach was used for data collection and analysis. Sampling of participants was purposive, using a maximum variation approach, and data were analysed using thematic analysis. Participants were recruited from the maxillofacial clinic at a tertiary facility in Brisbane, Queensland, Australia. RESULTS: Twenty-one participants took part in the study. Findings described individual and structural factors that influenced the management of oral health post-treatment. Individual determinants of oral health behaviours included a cognitive shift towards lifelong oral health; management of unexpected barriers; and management of competing priorities. Structural factors included availability, accessibility of services, and continuity of care. The ability to fund oral health emerged as a salient theme that influenced both individual and structural factors. CONCLUSIONS: Strong self-efficacy and financial and spousal support enhanced the management of oral health, whereas difficulty managing competing issues post-treatment, such as psychological and financial stress, limited participants' capacity to prioritize and manage oral health. Policy initiatives are needed to address the structural barriers caused by a lack of timely access to general and preventive dental care post-treatment.