Study On The Optimization Of Oral Chewing Efficiency Test Method And Its Influencing Factors

Food oral processing is the process by which food enters the mouth,followed by being manipulated,broken down,transported,decomposed and digested,then swallowed.It is an important process for consumers to perceive the texture and flavor properties of the food.Individuals with different oral physiological characteristics and oral chewing behaviours differ greatly in food fragmentation,food texture and flavor perception.In this study,144 healthy subjects were recruited,and the differences in chewing efficiency（sugar release method）,oral physiological characteristics,and chewing behaviour of subjects in different groups were analyzed.The correlation between chewing efficiency and oral physiological parameters and chewing behaviour parameters were explored.The chewing efficiency test method was optimized and validated in 8 healthy subjects.A new method for evaluating the effective occlusal area of dentition and tongue transport capacity was established,and its relationship with chewing efficiency was explored in 20 healthy subjects.The main research contents and conclusions are as follows:（1）Participants of different ages（youth,elderly）,ethnicities（Han population in eastern China,New Zealand-born European）and gender（male,female）were taken as the research subjects to test their chewing efficiency（sugar release method）,oral physiological characteristics（unstimulated saliva flow rate,maximum tongue pressure,maximum bite force）and chewing behaviour.The results showed that the chewing efficiency measured by the sugar release method was significantly different between the Chinese and New Zealand participants recruited in this chapter（p<0.01）,and no significant difference was found in terms of gender and age.There were some differences in oral physiological characteristics and chewing behaviours in terms of age,ethnicity and gender;the chewing efficiency values measured by the sugar release method were only significantly related to the unstimulated saliva flow rate in oral physiological parameters,but the correlation coefficient is weak（r=-0.188）;the chewing efficiency values were only significantly correlated with the bite size and the chewing frequency in the chewing behaviour parameters,but the correlation coefficient is weak（r=-0.221,r=0.328）.There is still a certain gap with the existing literature,the possible reason is that the method of measuring the chewing efficiency using the release of sugar content is less accurate,and it has poor discrimination for healthy participants.（2）By analyzing the particle size distribution produced by chewing,the sieving method was optimized,and a new image analysis method was established to measure the chewing efficiency.The results show that the difference between the subtracting the 0.25 and 0.50 mm sieve layer and the standard sieving method was negligible(the average percentage difference of X₅₀ and b were less than 1%);the subtraction of 0.25,0.50,0.71 mm sieve layer can meet the requirements of the sieving method for testing the chewing efficiency(the average percentage difference of X₅₀ and b were less than 5%);The 2D to 3D modeling method to evaluate the irregular particle size distribution is feasible and reliable.The image analysis method can replace the sieving method to accurately measure the chewing efficiency.（3）By using the wax impression method,the effective occlusal area was measured,and the transport capacity of the tongue at the first bite was evaluated,and its relationship with the chewing efficiency was explored.The results showed that the wax impression method can effectively evaluate and distinguish the individual variations of effective occlusal area.The effective occlusal area has a significant positive linear correlation with the chewing efficiency（r=-0.573,p<0.01）.The larger the effective occlusal area,the better the chewing efficiency.The small wax impression test can effectively evaluate and distinguish the individual variations of the transport capacity of the tongue.The tooth print area obtained in the test has a significant positive linear correlation with the chewing efficiency（r=-0.497,p<0.05）.The larger the tooth print area,the better the chewing efficiency.Effective occlusal area and tongue transport capacity can partially,not comprehensively,explain the oral physiological factors in the variations of chewing efficiency.It is still necessary to further investigate other oral factors that affect chewing efficiency.