A dental revolution: The association between occlusion and chewing behaviour

Dentistry is confronted with the functional and aesthetic consequences that result from an increased prevalence of misaligned and discrepant dental occlusal relations in modern industrialised societies. Previous studies have indicated that a reduction in jaw size in response to softer and more heavily processed foods during and following the Industrial Revolution (1,700 CE to present) was an important factor in increased levels of poor dental occlusion. The functional demands placed on the masticatory system play a crucial role in jaw ontogenetic development; however, the way in which chewing behaviours changed in response to the consumption of softer foods during this period remains poorly understood. Here we show that eating more heavily processed food has radically transformed occlusal power stroke kinematics. Results of virtual 3D analysis of the dental macrowear patterns of molars in 104 individuals dating to the Industrial Revolution (1,700–1,900 CE), and 130 of their medieval and early post-medieval antecedents (1,100–1,700 CE) revealed changes in masticatory behaviour that occurred during the early stages of the transition towards eating more heavily processed foods. The industrial-era groups examined chewed with a reduced transverse component of jaw movement. These results show a diminished sequence of occlusal contacts indicating that a dental revolution has taken place in modern times, involving a dramatic shift in the way in which teeth occlude and wear during mastication. Molar macrowear suggests a close connection between progressive changes in chewing since the industrialization of food production and an increase in the prevalence of poor dental occlusion in modern societies.

Dental microwear texture gradients in guinea pigs reveal that material properties of the diet affect chewing behaviour

Dental microwear texture analysis (DMTA) is widely used for diet inferences in extant and extinct vertebrates. Often, a reference tooth position is analysed in extant specimens, while isolated teeth are lumped together in fossil datasets. It is therefore important to test whether DMT is tooth position specific, and if so, what the causes for wear differences are. Here we present results from controlled feeding experiments with 72 guinea pigs, which either received fresh or dried natural plant diets of different phytolith content (lucerne, grass, bamboo), or pelleted diets with and without mineral abrasives (frequently encountered by herbivorous mammals in natural habitats). We test for gradients in dental microwear texture along the upper cheek tooth row. Regardless of abrasive content, pelleted diets display an increase in surface roughness along the tooth row, indicating that posterior tooth positions experience more wear compared to anterior teeth. Guinea pigs feedings on plants of low phytolith content and low abrasiveness (fresh and dry lucerne, fresh grass) show almost no DMT differences between tooth positions, while individuals feeding on more abrasive plants (dry grass, fresh and dry bamboo) show a gradient of decreasing surface roughness along the tooth row. We suggest that plant feeding involves continuous intake and comminution by grinding, resulting in posterior tooth positions mainly processing food already partly comminuted and moistened. Pelleted diets require crushing, which exerts higher loads, especially on posterior tooth positions, where bite forces are highest. These differences in chewing behaviour result in opposing wear gradients for plant versus pelleted diets.

TINGKAH LAKU MENGUNYAH KERBAU MOA YANG DIBERI HIJAUAN LOKAL DI PULAU MOA KABUPATEN MALUKU BARAT DAYA

The objective of the present study was to examined the chewing behaviour of Moa buffalo fed on local forages. The experiment was analysed as Latin square 4 x 4, four treatments and four replicates. The treatments were A (combination of graas and aulumadam), B (grass and knumge, C (grass and weru leaves) and D (grass).Variables measured were chewing during eating (intake rate, chewing rate and efficiency) and chewing during rumination (ruminating rate, time spent ruminating per bolus, rumination efficiency, and regurgitation rate). The result show that intake rate was 31.78, 30.52, 31.99, 32.14 gram/minutes for treatmen A, B, C and D, respectively. Chewing rate (no.of chew/minutes) for A, B, C and D was 50.81, 53.95, 56.50, and 55,67, reapectively, and chewing efficiency (no.of chews/dry weight) was 0.23, 0.31, 0.21, and 0.35 for A, B, C, and D, respectively. Ruminating rate (no of bolus/minutes) was 1.16, 1.06, 1.26, and 1.34 for A. B, C and D, respectively. Ruminating efficiency (no. of chews/bolus) for A, B, C, and D was 37.70, 43.68, 36.48 and 36.24, respectively. Time spent ruminating per bolus was 1.14, 0.96, 0.82. and 0.75 minutes for A, B, C, and D, respectivly, and regurgitation rate (minutes) was 0.16, 0.89, 1.46, and 0.44 for A, B, C, and D, respectively. It can be concluded than Moa buffalo consume all forages with similar rate and efficiency, while chewing rate differ among the the treatments. Chewing rumination is similar among all forages.

An EMG-based Eating Behaviour Monitoring System with Haptic Feedback to Promote Mindful Eating (Preprint)

BACKGROUND Mindless eating, or the lack of awareness of the food we are consuming, has been linked to health problems attributed to unhealthy eating behaviour, including obesity. Traditional approaches used to moderate eating behaviour often rely on inaccurate self-logging, manual observations or bulky equipment. Overall, there is a need for an intelligent and lightweight system which can automatically monitor eating behaviour and provide feedback. OBJECTIVE In this paper, we investigate: i) the development of an automated system for detecting eating behaviour using wearable Electromyography (EMG) sensors, and ii) the application of such a system in combination with real time wristband haptic feedback to facilitate mindful eating. METHODS Data collected from 16 participants were used to develop an algorithm for detecting chewing and swallowing. We extracted 18 features from EMG and presented those features to different machine learning classifiers. Based on this algorithm, we developed a system to enable participants to self-moderate their chewing behaviour using haptic feedback. An experiment study was carried out with 20 additional participants to evaluate the effectiveness of eating monitoring and haptic interface in promoting mindful eating. RESULTS Our proposed algorithm is able to automatically assess eating behaviour accurately using the EMG-extracted features and a Support Vector Machine (SVM): F1-Score=0.94 for chewing classification, and F1-Score=0.86 for swallowing classification. The experimental study showed that that participants exhibited a lower rate of chewing when haptic feedback delivered in forms of wristband vibration was used compared to a baseline and non-haptic condition (F (2,38) = 58.243, p <.001). CONCLUSIONS These findings may have major implications for research in eating behaviour, providing key insights into the impacts of automatic chewing detection and haptic feedback systems on moderating eating behaviour with the aim to improve health outcomes.

Application of electromyography (EMG) in food texture evaluation of different Indian sweets

The present study was undertaken to correlate surface electromyography variables acquired during chewing of different Indian sweets with the instrumental texture parameters and their sensory attributes. Firstly, a comparison of acquired absolute EMG variables with the relative EMG variables was conducted. The results revealed that the relative EMG mastication parameters can effectively distinguish different textured food products by eliminating the subject variance. Then, the two different recordings of masticatory parameters in an EMG session for human subjects were correlated to investigate the reproducibility of chewing patterns. The correlation coefficients were found to be statistically significant (p less than 0.05) indicating highly reproducible chewing behaviour within a session for human subjects. Finally, acquired surface EMG variables were clustered into six representative variables using dendrograms. The principal component analysis conducted for these representative variables could explain 76% of cumulative proportion of variance. The scores of first principal component correlated significantly with instrumental and sensory hardness and sensory stickiness, while scores of second component correlated with sensory stickiness.