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ABSTRACT Color- and form-labeled particles of Optosil (version 1980, a silicone rubber, Bayer, Leverkusen, Germany) have been used previously to quantify the underlying processes of food comminution, i.e., selection and breakage, in subjects with normal dentitions. The aim of this present study was to develop a weakened Optosil that is suitable for the study of selection and breakage in subjects with impaired chewing ability. Half cubes (4.8 × 9.6 × 9.6 mm) were subjected to load tests to determine the force, deformation and work at particle fracture for periods of up to 6 months. Methods of modifying Optosil were (1) heat-treating the base material to produce 'Optosoft'; (2) mixing the base of Optosil or Optosoft with a nonprescribed catalyst (Verone, Davis Schott Lander & Davis Ltd, Herts, England) to produce 'Optoweak' or 'Optosoft-weak' and (3) heating half cubes that were preweakened. A weakened and stable test food that is suitable for labeling and reuse has been obtained by color-dyeing the Optosoft base and using Verone ('dyed-Optosoft-weak'). PRACTICAL APPLICATIONS Every chewing cycle begins with selection, in which food particles have a chance to be placed between the teeth in such a way that they are at least damaged, if not broken, by the subsequent breakage process. Bite force is reduced in certain patients, e.g., patients with neuromuscular diseases, following orthognathic surgery and in full denture wearers, and the action of the tongue and cheeks differs when compared with healthy individuals. Both factors are important in selection and breakage. The artificial test food Optosil has a large fracture force so that it is difficult to chew for subjects with an impaired chewing ability. This problem has been solved by developing a weaker test food, i.e., 'dyed-Optosoft-weak.' This test food allows the study of selection and breakage in general with color- and form-labeled particles and to determine the effect of medication, orthognathic surgery or oral implants on these processes. [ABSTRACT FROM AUTHOR]

The role of texture and flavors in mastication is evident, but it is difficult to understand the interactions among food properties, oral physiology and perception. Mastication results from rhythmic mandibular movements. The teeth and masticatory muscles together form the mechanism whereby the food particles are fragmented. Masticatory performance and efficiency are defined as the capacity to reduce natural or artificial test materials during mastication, or by counting the number of strokes required to reduce food, respectively. Foods eaten for nourishment are very different from the industrial test materials used to quantify masticatory performance, thus, divergences could arise if the chewable material can or cannot be swallowed. This study presents a synopsis of masticatory performance methods, which is also related to muscle force, number of teeth and test chewing substance diversity. PRACTICAL APPLICATIONS The attributes of food, such as appearance, flavor and texture, as well as its interaction with saliva, number of teeth and conditions of the biomechanical system, influence the chewing process. In addition, reflex control and cognition can influence food perception and breakdown in the mouth. Food acceptability and choice depend on sensory properties of the food, which are perceived during chewing and swallowing. Masticatory performance and maximal occlusal force measurement may provide essential information that could lead to an appropriate diagnosis as regards masticatory function. Masticatory efficiency and performance can be measured to determine the individual's capacity to comminute a natural or a chewable test material. A material with uniform properties that can be reliably reproduced is essential to provide an ideal test bolus for the scientific study of masticatory effectiveness. [ABSTRACT FROM AUTHOR]

We analysed the effect of three portion sizes Optocal Plus (small, medium and large) on swallowing thresholds in subjects with either conventional complete dentures or mandibular implant-retained overdentures (transmandibular and permucosal cylindric implants). Tests were carried out in 52 women and 15 men (mean age 59 years) 4 years after treatment in a randomised controlled clinical trial. The results indicated that the degree of mucosal support for the mandibular denture did not affect the number of chewing strokes, time till swallowing or swallowed particle size. Only the chewing rate differed: subjects wearing mandibular implant-retained overdentures chewed the food at a higher rate than complete-denture wearers. With larger portion sizes, subjects needed significantly more chewing strokes and time until swallowing and they would have swallowed larger particles. Men chewed their food more efficiently than women, as they used the same number of chewing strokes and time, but achieved a greater particle size reduction at the swallowing moment. To cite this article: Fontijn-Tekamp FA, Slagter AP, Van der Bilt A, Van't Hof MA, Kalk W, Jansen JA. Swallowing thresholds of mandibular implant-retained overdentures with variable portion sizes. Clin. Oral Impl. Res. 15, 2004; 375–380 [ABSTRACT FROM AUTHOR]

summary The aim of this study was to develop an objective evaluation system for the masticatory function. This system used paraffin wax cubes as a test food, which had six red- and green-coloured layers so that each of the six surfaces showed a pseudo-checkered pattern. A total of 100 paraffin cubes were chewed by 37 subjects and the images of these samples were captured and analysed using a digital image analyzer. With regard to the colour and the shape of each sample, five parameters were obtained. Furthermore, an independent examiner graded the degree of colour mixing in the chewed samples into three groups (poor, medium and good) by visual inspection. A discriminant analysis was performed using the five variables as predictors of two groups (good and poor). Mixing Ability Index (MAI) was calculated from the discriminant function and using this index, 97% of the samples from these two groups were classified correctly. This system needed only a few minutes to complete and is easy to use. Therefore, it has high potentials for clinical use. [ABSTRACT FROM AUTHOR]