Adhesive strength and its improvement referring to the laminated‐type mouthguard

Abstract

The manufacture of laminated-type mouthguards requires skill in fusing sheets of mouthguard materials together. Adequate adhesive strength is required to use mouthguards in a stable condition for a long time. Therefore, in this study, the exfoliation test was applied and some treating techniques and conditions that improve the adhesive strength on a laminated surface were examined. Samples were laminated with two pieces of mouthguard material (3 mm thickness) having an adhesive area of 5 x 5 mm2, and whose other end was the holding part. The experimental factors used were as follows: heating time, use of solvent, elimination and direct heating of the laminate surface, colour of materials and water sorption. The result was measured at the time of breakage of the maximum load (N) and the form of destruction was examined. At 165 s of heating time, material failure was shown at under a load exceeding 5.0 N when compared to an untreated condition. Material failure was measured when a solvent was used and during the elimination of the laminated surface at a heating time of 150 s, which is 15 s lesser than in an untreated condition. Material failure was also measured by direct heating on the bonding surface of a second sheet of material at a heating time of 135 s, which is 30 s lesser than in an untreated condition. The differences in colour of the materials influence adhesion. Clear and light coloured materials showed higher adhesion ability. One-way analysis of variance confirmed a statistically significant difference in heating time differences, usage of solvent, elimination, direct heating on bonding surface and colour (P < 0.05). The decrease of adhesive strength by water sorption at 23 degrees and 37 degrees C was not observed significantly. Maximal laminated bond strength can be obtained by minimal heating time and proper treatment with the use of solvent, elimination and direct heating on bonding surface. The differences in the colour of the materials influenced adhesion. Clear and light coloured materials showed higher adhesive ability. Water sorption did not affect the adhesive strength. Therefore, if laminated-type mouthguards were manufactured properly, it can be used for a longer time and in a good condition.

Bonding durability of custom-made mouthpiece for scuba diving after water storage under pressure

“…Regarding the BS at FR of PO, the previously reported values were different from the values obtained in the present study 17) . This was due to the different specimen preparation.…”

“…Regarding the effect of water immersion, the bonding strength of the EV material was not influenced by 23 or 37°C water immersion for 1 month 17) . The ratios of the BS at SD of PO in 0.2 MPa water to that in air were 84.2% for 1w and 83.9% for 4w; those of EV were 82.7% for 1w and 80.7% for 4w.…”

“…However, the T-shape shear test has been one of the most popular test methods and the bond strength at the fracture has been discussed 16,17) . The load-displacement curve during the delamination test showed an S-shape (Fig.…”

“…A T-peel test was used as the delamination test 16,17) . Two sheets of the same mouthguard material in different colors were laminated together.…”

Easy fabrication of a new type of mouthguard incorporating a hard insert and space and offering improved shock absorption ability

“…In thermoformation of the third, 2-mm EVA sheet a number of factors in addition to those described above need to be taken into consideration in improving layer-to-layer adhesive strength (28). At 30 seconds of heating, the third EVA layer is turned over, making the heated surface the bonding surface (Fig.8).…”