The extent and nature of dental anxiety in Australians experiencing homelessness.

High dental anxiety is a major barrier to accessing dental care and has been found to be experienced to a greater extent in the homeless population. No studies have investigated the extent and nature of dental anxiety in Australians experiencing homelessness and was the aim of this study. Participants were recruited from four not-for-profit organisations in inner Brisbane using convenience and snowball sampling. The Dental Anxiety Questionnaire (DAQ) and the Index of Dental Anxiety and Fear (IDAF-4C+ ) questionnaire and oral health screening were completed by people experiencing homelessness in Brisbane, Australia, and compared to population norms. Descriptive statistics were calculated, and non-overlapping confidence intervals considered significantly different. The majority of the participants (n = 66) were male, a current smoker, unemployed and living in government supported housing. Most of the participants rated their oral health as poor/fair (n = 46, 71.9%) and their oral function as good or higher (n = 34, 53.1%). Using the single-item DAQ, 28.2% (n = 19) of people experiencing homelessness had high dental anxiety, compared to 16% of the general Australian population. The mean summed IDAF-4C+ fear module score was 18.02 (CI 15.60-20.43), which was significantly higher than the Australian population (µ = 14.40, CI 13.93-14.86). The highest mean score in the IDAF-4C+ stimulus module was feeling embarrassed or ashamed as anxiety inducing (µ = 2.27, CI 1.89-2.64) and was significantly different from the general Australian population (µ = 1.40, CI 1.33-1.47). The poorer overall self-rated oral health by the homeless population may induce feelings of embarrassment or shame, highlighting the differing psychosocial aspect to dental anxiety experienced by this population. Managing dental anxiety is needed to improve accessing to dental care for this population. Multidisciplinary care from social workers, mental health workers and dental practitioners may be beneficial in managing fear.

Ligament regeneration using an absorbable stent-shaped poly-L-lactic acid scaffold in a rabbit model.

PURPOSE: Ligaments are frequently damaged in sports activities and trauma, and severe ligament injury can lead to joint instability and osteoarthritis. In this study, we aimed to regenerate the medial collateral ligament (MCL) using an absorbable stent-shaped poly-L-lactic acid (PLLA) scaffold in a rabbit model to examine the biocompatibility and mechanical properties. METHODS: Twenty-three Japanese white rabbits were used in this study. MCL defects were surgically created in the knee joints and then reconstructed using stent-shaped PLLA scaffolds. As controls, flexor digitorum longus (FDL) tendons were implanted into the contralateral knees. Seven rabbits were sacrificed at three time points, conducted four, eight and 16 weeks after the operation. The regenerated tissues were histologically evaluated using fibre alignment scoring, morphology of fibroblast scoring and immunohistochemical analysis of types I and III collagen. The regenerated tissues were also biomechanically evaluated by measuring the ultimate failure load and stiffness. RESULTS: At four weeks post-operation, spindle-shaped cells were observed on the inside of the scaffolds. At eight weeks, maturation of the regenerated tissues and collagen fibre alignment parallel to the ligaments was observed. At 16 weeks, the fibre alignment had become denser. The fibre alignment and morphology of fibroblast scores significantly increased in a time-dependent manner. Expression of type I collagen was more strongly observed in the scaffold group at eight and 16 weeks post-operation than at four weeks. Type III collagen was also observed at four, eight and 16 weeks post-operation. A thin layer of fibrocartilage was observed at the ligament-bone junction at eight and 16 weeks. The ultimate failure load of the scaffold group was 46.7 ± 20.7 N, 66.5 ± 11.0 N and 74.3 ± 11.5 N at four, eight and 16 weeks post-operation, respectively. There was no statistical difference between the normal MCL and the scaffold group at 16 weeks post-operation. CONCLUSIONS: The stent-shaped PLLA scaffold allowed for MCL regeneration with type I collagen expression and fibrocartilage formation and resulted in sufficient mechanical function.

Atomic beam-induced fluorination of polyimide and its application to site-selective Cu metallization.

Metallization methods of polyimide by hyperthermal atomic oxygen and atomic fluorine beams were developed. An atomic fluorine beam with a translational energy of 6.2 eV modified the wettability of polyimide surfaces to provide an advancing water contact angle of 132 degrees. It was confirmed that in-air storage for 2 months did not alter the hydrophobic property created by the atomic fluorine beam. This stable beam-induced surface fluorination technique was then applied to site-selective electroless Cu plating on polyimide. It was demonstrated that changing the exposure sequence could create both positive- and negative-type plating processes.