Comparison of adhesiveness of chewing gum to hard and soft denture base materials.

PURPOSE: The purpose of this study was to compare the adhesiveness of chewing gum to hard and soft denture base materials to investigate food retention associated with the basal surface of the denture. METHODS: Test specimens were fabricated using acrylic resin[Re], cobalt-chromium alloy[Co], zirconia[Zr], silicone soft relining material[SS], and acrylic soft relining material[AS]. Samples were set on a top-and-bottom pair lifting platform equipped with a digital force gauge. The experimenter chewed 3.0 g of chewing gum for 5 min. After surface saliva was wiped off, the chewing gum was placed on the lower test fragment and compressed until the distance between the upper and lower test fragments decreased to 1 mm. The upper test fragment was pulled at a crosshead speed of 100 mm/min. Adhesiveness was measured under dry conditions, and under wet conditions with inter-positioned artificial saliva. RESULTS: Under dry conditions, the adhesive strength was 17.04 ±â€¯1.99 N for Re, 12.88 ±â€¯2.20 N for Co, 3.80 ±â€¯1.03 N for Zr, 5.76 ±â€¯1.41 N for SS, and 12.54 ±â€¯2.44 N for AS. Under wet conditions, the adhesive strength was 5.26 ±â€¯1.64 N for Re, 0.96 ±â€¯0.21 N for Co, 3.32 ±â€¯0.40 N for Zr, 5.20 ±â€¯1.35 N for SS, and 6.78 ±â€¯1.97 N for AS. CONCLUSIONS: Among the hard denture base materials, zirconia recorded low adhesiveness and Re recorded high adhesiveness under both wet and dry conditions. The adhesiveness of Co was low under wet conditions but high under dry conditions. Among the soft denture base materials, SS under dry conditions recorded lower adhesiveness than that of AS. The adhesiveness of SS was low under both wet and dry conditions.