Why an artificial masticator?

The inside of the mouth is not accessible during normal mastication, and food bolus can only be partially collected in vivo.

This apparatus was conceived to simulate mastication and replicate the formation of a food bolus. It enables a steady control of the process and makes it possible to collect the bolus at any time during the mastication sequence.

The artificial masticator AM2 simulates the mechanical actions occurring during mastication to breakdown solid food. It enables the reproduction of a food bolus in various physiological conditions (temperature, saliva, developed forces…), to replicate a normal or deficient mastication, which is specific of the target population (elderly, children…)

The AM2 gives detailed information of food modification during or at the end of the mastication sequence and helps us overcome the inherent difficulty of studying human mastication.

Working principle

The AM2 working principle is based on the opposition of two “jaws” (mandibular and maxillary disks), one fixed and one mobile, each one wearing a “dental arch”. These « dental arches » exhibit a masticatory surface similar to the dental surface used during human mastication. They do not mimic the human anatomy but were conceived to impose the same compression and shearing stress to that developed in an in vivo mastication (Peyron & Woda, Current Op Food Sci, 2016). These “jaws” are activated through processor-operated motors (Woda et al, J Biomechanics, 2010).

The primary parameters controlled by the experimenter are:

• the type of mastication : periodic, chewing (children), tongue-palate compression (edentulous persons) …
• the type of stress applied to the food by the jaws : shearing/compression associated with vertical and lateral movements of the lower jaw.
• the number of masticatory cycles, the duration of those cycles or of the mastication sequence.
• the mastication force range to apply according to the hardness of the chewed food
• the use of artificial saliva, of composition (minerals, glycoporteins, enzyms…) and injection quantity/frequency adjustable, or human saliva.
• the mastication chamber temperature.

AM2 validation

The AM2 artificial masticator validation was done comparing particle size distribution in food boluses from in vivo “good” mastication of healthy volunteers and in vitro mastication with the AM2 apparatus (Mishellany-Dutour et al, Food Qual Pref, 2011).

The obtained in vitro food bolus has the same granulometric properties that that observed after in vivo mastication. Therefore, this tool can produce food boluses comparable to that produced in vivo (Figures 3 and 4). This result is obtained by implementing similar movements and forces to that developed in vivo.                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

Analysis of food bolus: Scientific questions raised

The artificial masticator is set to produce food bolus for different scientific objectives. It can be programmed to replicate normal or deficient mastication.

• characterization of physical and biochemical properties of food bolus at the time of swallowing: particle size and/or rheological measures, saliva impregnation, enzymatic saliva digestion…
• kinetics of bolus formation in terms of physical and biochemical properties …
• analysis of food components: nutrients released from the food matrix during mastication (bio-accessibility), biochemical modifications of nutrients by saliva (oral digestion…)
• production of food bolus for the artificial digestive system / digestibility measures or kinetic of intestinal bio-accessibility.
• formulation and food texture (intended for human of animals), behavior in mouth …
• behavior test of dental materials in oral conditions (wear…)
•  oral release of medication active agents (galenic) or toxic components, food-grade pollutants

Application field

The development of this masticator is the outcome of more than 20 years of research and collaboration that led us to have a broad knowledge and good expertise on the physiology of the masticatory function, and its translation into a controlled electro-mechanical system.    

Regardless of the considered food, programming the device is systematically realized by comparing the granulometry of bolus obtained in vivo and in vitro, and successive adjustments of the parameters: number of masticatory cycles, type of stress, force to apply, normal or deficient mastication, type and amount of saliva, etc… It enables in vitro mastication of any kind of solid or semi solid foods.  

The AM2 masticator was developed to answer various scientific questions and demands from extensive fundamental research fields (nutrition, oral physiology…), food sciences (development of new products for example), pharmacy/galenic, human and animal nutrition, on specific target populations (edentulous elderly, with or without dentures, children…), in the medical and dental field, material wearing test …etc.