A breakage index for characterizing in vitro nut fragmentation and predicting human oral fragmentation.

Breakage of food influences eating experience and sensory perception. The aims of the study were to identify an appropriate breakage index and to develop an in vitro method for predicting the ease of oral breakage of nuts. Kernels of five types of nuts were fragmented in vitro using a texture analyzer and 12 subjects therefore performed molar bites.

Consensus on the terminologies and methodologies for masticatory assessment.

A large number of methodological procedures and experimental conditions are reported to describe the masticatory process. However, similar terms are sometimes employed to describe different methodologies. Standardisation of terms is essential to allow comparisons among different studies.

The Influence of Initial Breakage on Size Reduction during Habitual Chewing of a Solid Test Food.

Objectives: Food comminution during chewing is due to intra-oral particle selection and subsequent breakage. Under conditions of habitual chewing and a nearly complete selection, the influence of initial breakage on particle size reduction was studied in trials with a first chewing cycle (N = 1) from a sequence of randomized trials with various cycle numbers. Furthermore, relationships were examined between degree of fragmentation from breakage (r-fr), molar maximal bite force (MBF) and chewing efficiency (the number of cycles needed to half the initial particle size, N(1/2-Xo)).

Oral physiological characteristics among Chinese subjects in the eastern region of China.

Objectives: With an increasing number of elderly in China, it becomes imperative to establish a comprehensive understanding of their physiological capabilities and investigate fundamental mechanisms underpinning the discrepancies between Chinese individuals and other ethnical groups, which will facilitate government policymaking, design and development of special food products.

Design: In this study, 100 healthy Chinese subjects in the eastern region of China (22-89 years old) were recruited with full consent, then divided into young adult, middle-aged and elderly groups. Subjects' maximum biting force (MBF), maximum tongue pressure (MTP), maximum oral volume (MOV), and saliva flow rate were recorded.

Locking up of food between posterior teeth and its influence on chewing efficiency.

Objectives: Food particles are intra-orally locked up between antagonistic posterior teeth, during each chewing cycle. Food locking up (FL) may enhance selection of particles for subsequent breakage, hence chewing efficiency (CE). The two aims were to determine FL, and to examine the relationship between FL and CE.

Optimizing a determination of chewing efficiency using a solid test food.

A test using a solid food is relevant to measure chewing ability (CA) as (a) it includes an integrated functioning of all oral structures involved, (b) an impairment of chewing a solid food causes inevitably diet restrictions, and (c) chewing efficiency (CE) can easily be defined. CE is the number of chewing cycles, N(1/2-Xo), needed to attain a particular chewing outcome (a median particle size, X , which is half the initial particle size Xo) whereas chewing performance (CP) is a state of chewing outcome (X ) at an arbitrary number of chewing cycles. The use of CE is preferable for CA because inter-subject ratios are constant regardless of the initial conditions of the test food.

Determining chewing efficiency using a solid test food and considering all phases of mastication.

Objectives: Following chewing a solid food, the median particle size, X, is determined after N chewing cycles, by curve-fitting of the particle size distribution. Reduction of X with N is traditionally followed from N ≥ 15-20 cycles when using the artificial test food Optosil, because of initially unreliable values of X. The aims of the study were (i) to enable testing at small N-values by using initial particles of appropriate size, shape and amount, and (ii) to compare measures of chewing ability, i.

Selection in mixtures of food particles during oral processing in man.

Objectives: Two processes underlie food comminution during chewing: (1) selection, i.e. every particle has a chance of being placed between the teeth and being subjected to (2) breakage.

Towards an optimal therapy strategy for myogenous TMD, physiotherapy compared with occlusal splint therapy in an RCT with therapy-and-patient-specific treatment durations.

Background: Temporomandibular Disorders (TMD) may be characterized by pain and restricted jaw movements. In the absence of somatic factors in the temporomandibular joint, mainly myogenous, psychobiological, and psychosocial factors may be involved in the aetiology of myogenous TMD. An occlusal appliance (splint) is commonly used as a basic therapy of the dental practice.

The index 'Treatment Duration Control' for enabling randomized controlled trials with variation in duration of treatment of chronic pain patients.

Background: Treatment duration varies with the type of therapy and a patient's recovery speed. Including such a variation in randomized controlled trials (RCTs) enables comparison of the actual therapeutic potential of different therapies in clinical care. An index, Treatment Duration Control (TDC) of outcome scores was developed to help decide when to end treatment and also to determine treatment outcome by a blinded assessor.

Selective stimulation of human tooth-pulp with a new stable method: responses and validation.

Introduction: The aims of this study were to establish a safe technique for selective stimulation of nerves in human tooth-pulp during long experiments and to validate its use even with stimuli of high intensities.

Methods: A custom-made veneer containing 2 silver wire-conductive cream electrodes was attached with cement to the labial surface of an upper central incisor tooth. A variety of stimulus intensities were applied, and sensory and reflex responses from jaw-closing muscles were recorded.

The influence of auditory and visual information on the neuromuscular control of chewing crispy food.

The influence of auditory and/or visual information on the neuromuscular control of chewing a crispy food was investigated. Participants chewed biscuits of three different levels of crispness under four experimental conditions: no masking, auditory masking, visual masking, and auditory plus visual masking. The order of the four masking condition blocks was randomized.

Oral function after oncological intervention in the oral cavity: a retrospective study.

Purpose: To assess self-perceived oral function of patients with oral cavity cancer at different stages of treatment, ie, before oncologic intervention, 5 weeks after intervention, and 5 years after intervention.

Patients And Methods: A cohort of 158 patients with malignancy in the oral cavity treated by surgery in 1999 or 2000 was included. From this cohort we interviewed 69 patients by telephone in 2005 and collected data on dental status, disorders of chewing and swallowing, xerostomia, preference of food consistency, tube nutrition, weight loss, and speech for different stages of treatment.

Statistically and clinically important change of pain scores in patients with myogenous temporomandibular disorders.

A within-patient change in pain score after treatment is statistically 'reliable' when it exceeds the smallest detectable difference (SDD). The aims of the present study were (i) to determine SDD for scoring pain behavior on a 0-5 point adjectival scale, and (ii) to explore the relationship between SDD, clinically important difference (CID) and effect size (ES) following treatment of known efficacy, and to compare these parameters of pain behavior with those of VAS-scores of pain intensity [van Grootel RJ, van der Bilt A, van der Glas HW. Long-term reliable change of pain scores in individual myogenous TMD patients.

Dissociation of nociceptive modulation of a human jaw reflex from the influence of stress.

In human beings, inhibitory jaw reflexes can be depressed by painful stimulation of remote parts of the body. Since similar effects can be produced by the stress of anticipating pain, we wished to investigate whether the effects of remote painful stimuli are dependent on stress. EMG recordings were made from a masseter muscle while subjects maintained activity in the muscle at approximately 12.

Functional roles of oral reflexes in chewing and biting: phase-, task- and site-dependent reflex sensitivity.

Because loading during chewing is not totally predictable and jaw-closing muscles are strong and act over short distances, feedback from oral receptors is important in the control of mastication. Information on such feedback can be obtained by studying reflexes in jaw muscle EMGs. This review will deal with the contribution of reflex mechanisms to modifying motor neuron activity during chewing, and the dependency of reflex sensitivity on motor task, phase of movement, and site of stimulation.

Long-term reliable change of pain scores in individual myogenous TMD patients.

A within-patient change in pain score after treatment is statistically 'reliable' when it exceeds the smallest detectable difference (SDD). The aims of the present study were to: (i) determine SDDs for VAS-scores of pain intensity, for sufficiently long test-retest intervals to include most biological fluctuations, (ii) examine whether SDD is invariant to baseline score, and (iii) discuss the value of reliable change (RC) for detecting clinically important difference (CID) or as a possible indicator of successful treatment. SDDs were determined using duplicate data from 118 patients with myogenous Temporomandibular disorders: (1) VAS-scores of pain intensity from the masticatory system in a pre-treatment diary, and (2) VAS-scores of pain intensity from the hand (cold-pressor test).

Differentiation of nociceptive- from stress-induced modulatory influences on human reflexes.

This paper describes a new protocol that addresses the question of whether, in human experiments, modulatory effects of remote nociceptive conditioning stimuli on reflex responses are mediated by the stress induced by the conditioning stimuli. The protocol has been illustrated by a study into the effect of a remote nociceptive conditioning stimulus on an inhibitory jaw reflex. Electromyograms were recorded from an active masseter muscle and inhibitory reflexes were evoked by applying electrical stimuli to the upper lip.

Patterns of pain variation related to myogenous temporomandibular disorders.

Objectives: Myogenous temporomandibular disorders are characterized by jaw muscle pain. The aims were: 1) to characterize this pain generally in terms of intensity, frequency, duration, and behavior across a period of 2 weeks; 2) to identify main intraday pain patterns and to examine whether subgroups of patients in this respect differed in clinical, demographic, pain and sleep variables, psychosocial factors, and use of medication; and 3) to investigate some possible interday trends of pain intensity at a group level.

Method: One hundred thirty-three patients with myogenous temporomandibular disorders completed a 2-week diary, rating pain intensity (100 mm Visual Analog Scale [VAS]), duration, behavior (verbal 6-point scale), and medication use on 4 times of the day.

Remote noxious stimuli modulate jaw reflexes evoked by activation of periodontal ligament mechanoreceptors in man.

The purpose of the study was to investigate whether jaw reflexes evoked by selective stimulation of periodontal ligament me canoreceptors are susceptible to modulation by remote noxious stimulation. Experiments were performed on 10 volunteer subjects. Skin surface recordings were made from the jaw-closing masseter muscle.

The relationship of facial two-point discrimination to applied force under clinical test conditions.

When an interside comparison is hampered, for example, in cases of bilateral trauma, normal threshold values of two-point discrimination from healthy subjects might be used to delineate abnormal from normal sensory function in patients. To determine threshold pin distances, two devices, the Disk-Criminator and the Aesthesiometer, have often been applied in a clinical setting. Because these devices are hand-operated, the force of applying a device might vary considerably.