Age and perception of dental appearance and tooth colour

Objectives: To determine the prevalence of satisfaction with dental appearance and own tooth colour in the UK and investigate the impact of ageing on these perceptions. Methods: Data about ageing and satisfaction with dental appearance and tooth colour was gathered by means of a questionnaire completed at face‐to‐face interview. The questionnaire was first tested and then used by the Office of National Statistics (ONS) in a stratified random sample of adults drawn from the UK. A total of 3384 adults were interviewed. Results: Three quarters of the population were satisfied with their own dental appearance and two‐thirds were satisfied with their tooth colour. Subjects over the age of 55 were significantly more likely to be satisfied with their dental appearance and tooth colour (p < 0.05) compared with younger age groups. Conclusions: Ageing is not necessarily associated with negative self‐perception of dental appearance or tooth colour. Greater dissatisfaction with dental appearance or colour in younger ages may suggest that perceived appearance is linked to cognitive factors other than social or cultural ones.     

Dental caries in wild primates: Interproximal cavities on anterior teeth

Dental caries has been reported in a variety of primates, although it is still considered rare in wild populations. In this study, 11 catarrhine primate taxa (n = 339 individuals; 7946 teeth) were studied for the presence of caries. A differential diagnosis of lesions in interproximal regions of anterior teeth was undertaken, since they had been previously described as both carious and non-carious in origin. Each permanent tooth was examined macroscopically, with severity and position of lesions recorded. Two specimens were examined further, using micro-CT scans to assess demineralization. Differential diagnosis confirmed the cariogenic nature of interproximal cavities on anterior teeth (ICATs). Overall results show 3.3% of all teeth (i.e., anterior and posterior teeth combined) were carious (n = 262), with prevalence varying among species from 0% to >7% of teeth affected. Those with the highest prevalence of ICATs include Pan troglodytes verus (9.8% of anterior teeth), Gorilla gorilla gorilla (2.6%), Cercopithecus denti (22.4%), Presbytis femoralis (19.5%), and Cercopithecus mitis (18.3%). ICATs make up 87.9% of carious lesions on anterior teeth. These results likely reflect dietary and food processing differences among species, but also between the sexes (e.g., 9.3% of all female P. troglodytes verus teeth were carious vs. 1.8% in males). Processing cariogenic fruits and seeds with the anterior dentition (e.g., wadging) likely contributes to ICAT formation. Further research is needed in living primate populations to ascertain behavioral/dietary influences on caries occurrence. Given the presence of ICATs in frugivorous primates, their diagnosis in archaeological and paleontological specimens may shed light on diet and food processing behaviors in fossil primates.     

Influence of connection type on the biomechanical behavior of distal extension mandibular removable partial dentures supported by implants and natural teeth

Few studies are performed to evaluate the influence of connection type on the stress distribution of distal extension mandibular removable partial dentures (RPDs) supported by both implants and natural teeth. In this study, five three-dimensional finite element models were prepared to simulate mandibular bilateral partially edentulous arches. Four were RPDs supported by both implants and natural teeth, and the other one was RPDs supported only by natural teeth. The maximum equivalent (EQV) stress values of bone around implants, the abutments, and the mucosa displacements of the related supporting structures were measured. It was found that a non-rigid telescopic coping was more favorable to protect the implant than a rigid telescopic coping. Compared with other connection types, the easy resilient attachment (ERA) system seemed to be effective to associate implant without complications. However, the results obtained in the present study should be cautiously interpreted in the clinic.     

Attitudes to the importance of retaining natural teeth in an adult Swedish population

Objectives . To evaluate the attitudes to retaining natural teeth in an adult Swedish population, and to correlate the attitude to retaining natural teeth with some presumed influencing background factors. Design : Cross-sectional study using a newly developed questionnaire. Subjects : From the national census register of four municipalities in the southern part of the province of Halland, Sweden, with a total population of 126,878 adult (≥20 years) inhabitants, 4,200 persons were selected at random. The sample was randomised by age and sex, and 300 men and 300 women from the age groups 20, 30, 40, 50, 60, 70, and 80 years were included. Intervention and main outcome measures : The questionnaire aimed to evaluate the number of remaining natural teeth, the dental care habits, the self-estimated quality of natural teeth, and the attitude t o retaining natural teeth In the studied population, and also to evaluate the possible correlation between those factors, in particular, the attitude to retaining natural teeth versus the other factors. Results : It was found that the attitude to the importance of retaining natural teeth was strongly correlated with the number of remaining natural teeth, the dental care habits, and the self-estimated quality of natural teeth. Also sex had an influence on this attitude but not age. Conclusions : The attitude to the importance of retaining natural teeth in an adult Swedish population is correlated with the number of remaining natural teeth, the dental care habits, the self-estimated quality of natural teeth, and sex, but not with age.     

Collagen and keratin polypeptide models for assessing the natural and artificial protein decay of organic materials

Among the materials constituting the natural and cultural heritage, organic materials of proteinaceous origin as bone (collagen), parchment and woolen textiles (keratin) are the most susceptible to damage and decay because of their exposure to air pollution, inappropriate values of ambient temperature, humidity and light. Aiming at contributing to the development of a reliable and reproducible immunoassay for the evaluation of collagen and keratin decay, three polypeptide models of these proteins were designed, synthesized and studied. Polypeptide [Pro‐Ser(OBzl)‐Gly]_n incorporates the typical motif Pro‐X‐Gly of collagen; polypeptide [Pro‐Cys(Acm)‐Gly]_n is a model of the C‐terminal domain of type I keratin, corresponding to the repeating unit Pro‐Cys‐X of keratin, while polypeptide Ac‐YRSGGGFGYRSGGGFGYRS‐βAla‐NH₂ encloses the characteristic repeating sequence GGGFGYRS of the N‐terminal part of Type II keratin. These polypeptides may be considered as simplified models that mimic fragments of collagen and keratin resulting from artificial and natural ageing or decay. It is concluded that high recognition of anti‐polypeptide antibodies, produced after immunizations, by the bone, parchment and textile samples is indicative of high deterioration, while high anti‐collagen or anti‐keratin recognition is indicative of low deterioration. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.     

Tooth loss and dental caries in community-dwelling older adults in northern Manhattan

doi: 10.1111/j.1741‐2358.2011.00502.x Tooth loss and dental caries in community‐dwelling older adults in northern Manhattan Objective: To examine tooth loss and dental caries by sociodemographic characteristics from community‐based oral health examinations conducted by dentists in northern Manhattan. Background: The ElderSmile programme of the Columbia University College of Dental Medicine serves older adults with varying functional capacities across settings. This report is focused on relatively mobile, socially engaged participants who live in the impoverished communities of Harlem and Washington Heights/Inwood in northern Manhattan, New York City. Materials and Methods: Self‐reported sociodemographic characteristics and health and health care information were provided by community‐dwelling ElderSmile participants aged 65 years and older who took part in community‐based oral health education and completed a screening questionnaire. Oral health examinations were conducted by trained dentists in partnering prevention centres among ElderSmile participants who agreed to be clinically screened (90.8%). Results: The dental caries experience of ElderSmile participants varied significantly by sociodemographic predictors and smoking history. After adjustment in a multivariable logistic regression model, older age, non‐Hispanic Black and Hispanic race/ethnicity, and a history of current or former smoking were important predictors of edentulism. Conclusion: Provision of oral health screenings in community‐based settings may result in opportunities to intervene before oral disease is severe, leading to improved oral health for older adults.     

Influences of age and maxillary anterior teeth status on patient's satisfaction with dental appearance and tooth colour

doi: 10.1111/j.1741‐2358.2011.00543.x Influences of age and maxillary anterior teeth status on patient’s satisfaction with dental appearance and tooth colour Objectives: To study the impact of age, gender, tooth colour and maxillary anterior teeth status on patient’s satisfaction with their dental appearance. Material and methods: A total of 259 Caucasian subjects participated in the study (119 men, mean age 56 years; 140 women, mean age 61 years) divided into three age groups (young <35 age; middle aged 35–54 age; old ≥55 age). Their maxillary anterior teeth status was classified into three groups: (1) natural teeth (NTG) group; (2) composite filling group (CFG) and (3) porcelain‐fused‐to‐metal fixed prosthodontic restoration group (FPDG). The participants judged appearance and tooth colour using a scale with three categories: completely dissatisfied, moderately dissatisfied and completely satisfied. Results: Almost half of the participants were completely satisfied with their dental appearance and tooth colour. Half of the ‘young’ and ‘middle‐aged’ participants with natural maxillary anterior teeth were completely satisfied and half of the ‘old’ participants were moderately satisfied with their dental appearance and tooth colour. The majority of participants with composite restorations (45–51%) were moderately satisfied with their dental appearance, one‐third of ‘young’ and ‘middle‐aged’ participants were moderately satisfied or dissatisfied with their tooth colour and more than 70% of older participants were dissatisfied with their tooth colour (p > 0.05). Conclusions: Satisfaction with the appearance of the maxillary anterior teeth differed both between individuals of different age and different dental status.     

Cytological changes of the respiratory tract in young adults related to high levels of air pollution exposure

djuričić s. and plamenac p. (1998) Cytopathology 9, 23–28
Cytological changes of the respiratory tract in young adults related to high levels of air pollution exposure
Several histopathological and cytological studies have shown that lesions of the respiratory tract epithelium become increasingly severe with duration of exposure to high levels of urban air pollution as well as with ageing of studied population groups. In this study we investigated and compared findings of cytological abnormalities in sputa of young adults (21–25 years of age) exposed to high levels of air pollution since birth with those who were exposed in the last 2–3 years only. All subjects were non-smokers and were clinically healthy at the time of sampling. No significant differences in the incidence or severity of any of the cytological findings were found. The fact that even 10 times longer exposure to air pollution resulted in no major respiratory tract epithelial changes is, in our opinion, a result of the extremely efficient defence mechanisms and enormous regenerative potential of the respiratory tract of younger people.     

Number of natural and prosthetic teeth impact nutrient intakes of older adults in the United States

doi: 10.1111/j.1741‐2358.2011.00546.x Number of natural and prosthetic teeth impact nutrient intakes of older adults in the United States Objective: To examine the relationship between the number and type of teeth and nutrient intakes in adults, aged 60 years and above, in the National Health and Nutrition Examination Survey 1999–2004 using linear regression. Methods: Four discrete dental status groups were created: complete natural dentition (reference group), incomplete natural dentition, complete mixed (natural and restored) dentition and incomplete mixed dentition. We ran both unadjusted and adjusted models, controlling for age, race/ethnicity, education and smoking status to examine the effect of these covariates on the association between dentition status and nutrient intakes. Separate models were run for men and women. Results: There were significant associations between dental status and all the examined nutrients for men and for the carotenes and folate for women in the unadjusted model. Only caloric and vitamin C intakes were significant for men, and β‐carotene was significant for women in the adjusted model. For men for kilocalories and women for β‐carotene, those with a complete dentition had higher mean intakes than those with an incomplete dentition, regardless of the tooth type. Among men with an incomplete dentition, those with a mixed dentition had a significantly lower vitamin C intake than those with a natural dentition; there were no significant differences between the natural and mixed complete dentition groups. Conclusions: Demographic and behavioural variables explained many of the differences seen in nutrient intakes. After controlling for these variables, we found that a numeric threshold of teeth (i.e. a functional dentition) influenced some nutrient intakes while the number and type of teeth present affected other nutrient intakes.     

Homologies of the anterior teeth in indriidae

Schwartz ('74) proposed revised homologies of the deciduous and permanent anterior teeth in living lemuriform primates of the family Indriidae. Gingerich ('77) described a juvenile specimen of Avahi and emphasized the importance of functional integrity in controlling the pattern of dental reduction in primates, neither of which supports Schwartz's interpretation. Schwartz ('78) recently reiterated his position without adequately discussing the Avahi evidence and the functional basis that probably controls dental reduction. Avahi has a deciduous dentition intermediate in morphology between that of Lemuridae and Indriidae, and similar to both. Thus the lower deciduous dental formula of Indriidae is probably 2.1.3, which is the typical and maximum deciduous complement known in living and fossil lemuriform primates. The formula of the lower permanent dentition in Indriidae is thus 2.0.2.3.     

稻米外观品质性状遗传与分子定位研究进展

稻米外观品质主要是指稻米的粒形、垩白、透明度和籽粒色泽等,它不仅直接影响到人们的喜好,还与其他品质性状诸如蒸煮食用、加工等密切相关。因此,外观品质对稻米的商品价值有着十分重要的影响。本文从经典遗传与现代分子生物学两个方面对稻米主要外观品质的遗传研究进展进行了较全面的综述,包括粒长、粒宽、长宽比、粒厚、垩白、透明度和籽粒色泽等。综合近年来的遗传研究结果发现,大多数稻米外观品质性状都是由数量基因控制的。利用分子标记技术已将控制外观品质的QTL（qualitative trait locus）定位在不同的染色体上,为下一步的稻米外观品质改良提供了有利条件。     

The danger of applying the breeder's equation in observational studies of natural populations

The breeder's equation, which predicts evolutionary change when a phenotypic covariance exists between a heritable trait and fitness, has provided a key conceptual framework for studies of adaptive microevolution in nature. However, its application requires strong assumptions to be made about the causation of fitness variation. In its univariate form, the breeder's equation assumes that the trait of interest is not correlated with other traits having causal effects on fitness. In its multivariate form, the validity of predicted change rests on the assumption that all such correlated traits have been measured and incorporated into the analysis. Here, we (i) highlight why these assumptions are likely to be seriously violated in studies of natural, rather than artificial, selection and (ii) advocate wider use of the Robertson–Price identity as a more robust, and less assumption‐laden, alternative to the breeder's equation for applications in evolutionary ecology.