The softness and initial flow of temporary soft lining materials.

The initial flow of four temporary soft lining materials was studied with a simple laboratory test procedure, using a parallel-plate plastimeter. The flow in a clinical situation was further investigated, together with a clinical assessment of softness. The results indicate that a 2-mm thickness of temporary soft lining material is considered suitable for use as a tissue conditioner. The thickness of lining material is influenced by the clinical technique and by the powder to liquid ratio; however, the scope for altering the ratio is limited.link_to_subscribed_fulltex

Impact of the in situ formed salivary pellicle on enamel and dentine erosion induced by different acids

OBJECTIVE: To investigate and compare the protective impact of the in situ formed salivary pellicle on enamel and dentine erosion caused by different acids at pH 2.6. METHODS: Bovine enamel and dentine samples were exposed for 120 min in the oral cavity of 10 healthy volunteers. Subsequently, enamel and dentine pellicle-covered specimens were extraorally immersed in 1 ml hydrochloric, citric or phosphoric acid (pH 2.6, 60 s, each acid n=30 samples). Pellicle-free samples (each acid n=10) served as controls. Calcium release into the acid was determined by atomic absorption spectroscopy. The data were analysed by two-way ANOVA and Tukey's test (alpha=0.05). RESULTS: Pellicle-covered samples showed significantly less calcium loss compared to pellicle-free samples in all acid groups. The mean (SD) pellicle protection (% reduction of calcium loss) was significantly better for enamel samples [60.9 (5.3)] than for dentine samples [30.5 (5.0)], but revealed no differences among the acids. CONCLUSION: The efficacy of the in situ pellicle in reducing erosion was 2-fold better for enamel than for dentine. Protection of the pellicle was not influenced by the kind of acid when enamel and dentine erosion was performed at pH 2.6