Relationship between non‐ulcerative functional dyspepsia,occlusal pairs and masticatory performance in partially edentulous elderly persons

doi: 10.1111/j.1741‐2358.2010.00377.x
Relationship between non‐ulcerative functional dyspepsia, occlusal pairs and masticatory performance in partially edentulous elderly persons Objective: To relate occlusal state, masticatory performance and non‐ulcerative functional dyspepsia. Background: In spite of the relationship between gastric disturbances and number of present teeth being recognised, the influence of the number of occlusal pairs and masticatory performance, expressed as median particle size, has not been considered. Materials and methods: Thirty‐eight subjects (mean age = 71.8 ± 7.7 years) diagnosed with non‐ulcerative functional dyspepsia were selected. A further 38 healthy subjects (mean age = 71.9 ± 7.0 years) acted as controls. Subjects were subdivided according to their number of occlusal pairs: (1) 0–4, (2) 5–9 and (3) 10–14. Masticatory performance was evaluated by using the sieving method. Data were analysed using 2‐way anova and Bonferroni post‐hoc, Chi‐square and Odd ratio tests. Results: Subjects presenting with non‐ulcerative functional dyspepsia and 0–4 occlusal pairs showed the lowest masticatory performance (p < 0.01). No association between the dyspepsia and the number of occlusal pairs (χ² = 0.48, p = 0.785) was observed, however results showed association between functional dyspepsia and masticatory performance (χ² = 4.07, p = 0.0437) presenting an odds ratio = 3.46 (Confidence Interval = 0.99–12.10). Conclusion: Changes in masticatory performance were associated with the presence of non‐ulcerative functional dyspepsia.     

Macaque Masseter Muscle: Internal Architecture,Fiber Length and Cross-Sectional Area

Models of mastication require knowledge of fiber lengths and physiological cross-sectional area (PCS): a proxy for muscle force. Yet only a small number of macaques of various species, ages, and sexes inform the previous standards for masseter muscle architecture. I dissected 36 masseters from 30 adult females of 3 macaque species—Macaca fascicularis, M. mulatta, M. nemestrina—using gross and chemical techniques and calculated PCS. These macaques have mechanically similar dietary niches and exhibit no significant difference in masseter architecture or fiber length. Intramuscular tendons effectively compartmentalize macaque masseters from medial to lateral. Fiber lengths vary by muscle subsection but are relatively conservative among species. Fiber length does not scale with body size (mass) or masseter muscle mass. However, PCS scales isometrically with body size; larger animals have greater force production capabilities. PCS scales positively allometrically with facial size; animals with more prognathic faces and taller mandibular corpora have greater PCS, and hence force, values. This positive allometry counters the less efficient positioning of masseter muscles in longer-faced animals. In each case, differences in PCS among species result from differences in muscle mass not fiber length. Masseter PCS is only weakly correlated with bone proxies previously used to estimate muscle force. Thus predictions of muscle force from bone parameters will entail large margins of errors and should be used with caution.     

Spatial patterning of bone stiffness in the anterior mandibular corpus of Macaca fascicularis: Implications for models of bone adaptation

Elastic modulus of bone from the anterior mandibular corpus was determined via microindentation in a mixed-sex ontogenetic sample (N = 14) of Macaca fascicularis. This investigation focused on the hypothesis that material heterogeneity in the macaque mandibular symphysis—provided an accounting of age and sex variation—is explicable as a means to homogenize strains in this region. Experimental data and theoretical models of masticatory loading indicate that in the absence of material compensation, large strain gradients exist in the anterior mandibular corpus of macaques, particularly between lingual and labial cortical plates owing to the effects of lateral transverse bending. Microindentation data indicate that juvenile macaques possess less stiff bone than their subadult and adult counterparts; however, sex differences in elastic modulus are not apparent. Anisotropy variation is idiosyncratic; that is, there is not a common pattern of variation in stiffness sampled among orthogonal planes across individuals. Similarly, differences in stiffness between lingual and labial cortical plates, as well as differences among alveolar, midcorpus, and basal regions are inconsistently observed. Consequently, we find little evidence in support of the hypothesis that spatial variation in bone stiffness functions to homogenize strains in the anterior corpus; in fact, in some individuals, this spatial variation serves to exacerbate, rather than to minimize, strain gradients. The mechanical benefit of elastic modulus variation in the macaque mandibular symphysis is unclear; this variation may not confer adaptive benefit in terms of structural integrity despite the fact that such variation has discernible functional consequences. Am J Phys Anthropol 156:649–660, 2015. © 2014 Wiley Periodicals, Inc.     

Comparing ungulate dietary proxies using discriminant function analysis

A variety of tooth‐wear and morphological dietary proxies have been proposed for ungulates. In turn, they have been applied to fossil specimens with the purpose of reconstructing the diets of extinct taxa. Although these dietary proxies have been used in isolation and in combination, a consistent set of statistical analyses has never been applied to all of the available datasets. The purpose of this study is to determine how well the most commonly used dietary proxies classify ungulates as browsers, grazers, and mixed feeders individually and in combination. Discriminant function analysis is applied to individual dietary proxies (hypsodonty, mesowear, microwear, and several cranial dietary proxies) and to combinations thereof to compare rates of successful dietary classification. In general, the tooth‐wear dietary proxies (mesowear and microwear) perform better than morphological dietary proxies, though none are strong proxies in isolation. The success rates of the cranial dietary proxies are not increased substantially when ruminants and bovids are analyzed separately, and significance among the three dietary guilds is reduced when controlling for phylogenetic relatedness. The combination of hypsodonty, mesowear, and microwear is found to have a high rate of successful dietary classification, but a combination of all commonly used proxies increases the success rate to 100%. In most cases, mixed feeders bear the greatest resemblance to browsers suggesting that a morphology intermediate to browsers and grazers may represent a fitness valley resulting from the inability to exploit both browse and graze efficiently. These results are important for future paleoecological studies and should be used as a guide for determining which dietary proxies are appropriate to the research question. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Differences in the Mode of Growth Inhibition of Baker’s Yeast Brought about by Arsenate and Methanearsonate

The bite force of three surimi gels with molars was measured in the mouth using a multiple-point sheet sensor. A peak force appeared at the breaking point of each sample, and then the force increased again, accompanied by a decrease in the opening between the upeer and lower teeth. Low values in the peak force, pressure, and time at the first peak, the time at which the maximum contact area was engaged, impulse, and slope of bite curve were observed in samples with low breaking force and low breaking deformation found by the mechanical measurement of gel strength, and with less toughness in the sensory assessment. The duration of the bite force, the second peak time, and active bite pressure at the second peak did not change with a change in the surimi texture. The active pressure at the breaking point of each gel was affected by gel strength, while that at the second peak was independent of the gel strength.