Objective: Compare MP after 20 cycles and swallowing-threshold(ST), chewing-cycle-duration and the number of cycles till ST between young men/women with an artificial test-food.
Method: 100 women (mean age 21, range 18-25) and 100 men (mean 21, range 18-25) with a “normal-occlusion” and no temporomandibular/dysfunction, previous orthodontic/orthopedic treatment, missing teeth or extensive restorations were studied. Study was approved by the Institutional IRB. The artificial test-food (condensation silicon/Optosil Comfort®, Kulzer) was prepared following a standardized protocol. Tablets were 20mm in diameter, 5mm thick, hardness 63.4±.5 Shore-AU, and cut into quarters. The two different test procedures were chewing till ST and for 20 cycles. Chewed particles were dried and sieved (stack of seven sieves, 5.6, 4.0 2.8, 2, 0.85, 0.425, 0.025 mm) on a dental vibrator for two minutes. Median-particle-size (MPS) and broadness of particle distribution (BPD) were determined using the cumulative-weights on each sieve and the Rosin-Rammler-equation. Cycles were counted visually and cycle duration was registered using a stop-watch. Mann-Whitney U tests were performed for comparisons.
Result: MPS after 20 cycles was 17% larger for women than for men (p=.001), BPD after 20 cycles was 11% different (p=.361). MPS at ST was only 2% larger for women than men and this difference was not statistically significant (p=.952), BPD after ST was not different (p=.972). Chewing-cycle-duration was 16% longer in women (p=.000). The number of chews needed to reach ST was significantly different (p=.001); women need 9 more cycles than men (42.5 vs 33.6)to reach ST.
Conclusion: While men do have better MP than women after 20 cycles there is no difference for ST performance. Women compensate chewing more cycles but do not swallow larger food particles than men.