Inferring parrotfish (Teleostei: Scaridae) pharyngeal mill function from dental morphology, wear, and microstructure

Morphology, occlusal surface topography, macrowear, and microwear features of parrotfish pharyngeal teeth were investigated to relate microstructural characteristics to the function of the pharyngeal mill using scanning electron microscopy of whole and sectioned pharyngeal jaws and teeth. Pharyngeal tooth migration is anterior in the lower jaw (fifth ceratobranchial) and posterior in the upper jaw (paired third pharyngobranchials), making the interaction of occlusal surfaces and wear-generating forces complex. The extent of wear can be used to define three regions through which teeth migrate: a region containing newly erupted teeth showing little or no wear; a midregion in which the apical enameloid is swiftly worn; and a region containing teeth with only basal enameloid remaining, which shows low to moderate wear. The shape of the occlusal surface alters as the teeth progress along the pharyngeal jaw, generating conditions that appear suited to the reduction of coral particles. It is likely that the interaction between these particles and algal cells during the process of the rendering of the former is responsible for the rupture of the latter, with the consequent liberation of cell contents from which parrotfish obtain their nutrients.     

A traversodont cynodont from the Middle Triassic (Ladinian) of Baden-Württemberg (Germany)

Nanogomphodon wildi n. gen., n. sp. is based on a tiny lower postcanine tooth from the lower Lettenkeuper (Lower Keuper or Erfurt Formation; Ladinian) of Michelbach an der Bilz (Baden-Württemberg). It represents the first record of a traversodont cynodont from the Middle Triassic of Europe and exhibits a distinctive combination of dental features. Along with recent discoveries of other traversodont taxa from the Upper Triassic of eastern North America,Nanogomphodon indicates the existence of a distinct lineage of these cynodonts in the Northern Hemisphere.      

Notes on the postembryonic development and ecology of Grosphus hirtus Kraepelin, 1901 (Scorpiones, Buthidae) from the Parc National d’Ankarafantsika, northwest Madagascar

Among several specimens of Grosphus hirtus Kraepelin (Scorpiones, Buthidae), obtained in Madagascar, Mahajanga Province, Parc National d’Ankarafantsika, Station Forestière d’Ampijoroa, and then held in captivity, the courtship and mating behaviour of two females was observed. These two animals gave birth in captivity to 26 and 37 offspring of which two and three reached maturity, respectively. The duration of the five instars needed to reach the adult stage in both males and females averaged 14, 112, 117, 274, and 334 days. These developmental periods are much longer than those of Grosphus flavopiceus Kraepelin, the only other species in this genus studied, and longer than those of most examined species of Buthidae. Morphometric values for the different instars are presented from the individual offspring and from specimens collected in the wild. On the basis of these values, the average growth factor (Dyar's constant) per moult for three different measured structures was calculated from the pooled data. Dyar's constant is expressed for the first time in scorpions of the genus Grosphus. Instars growth factors are also comparable to other species of Buthidae.     

Determinants of local abundance and range size in forest vascular plants

Aim For a large set of forest herbs we tested: (1) whether there is a positive relationship between local abundance and geographical range size; (2) whether abundance or range size are affected by the niche breadths of species or niche availability; and (3) whether these are affected by the species life‐history traits. Location Northwestern Germany. Methods We measured abundance as mean density in 22 base‐rich deciduous forests and recorded range size as area of occupancy on four different spatial scales (local to national). Niche breadth was expressed in terms of habitat specificity (specialists, generalists) and of the ability to grow across a broad range of soil pH. The species’ pH niche position was used as a measure of the importance of habitat availability. As life‐history traits we used diaspore mass and number, plant height, seed longevity, lifespan/clonality, pollination mode, dispersal capability and flowering time. Results There were mainly no positive relationships between the abundance of species and their range size, as tested across species and across phylogenetically independent contrasts. Forest specialists were generally distributed less widely than generalists, but habitat specificity was not related to local abundance. Species with a broader pH niche breadth were more common, but the positive relationships between niche breadth and abundance or range size disappeared when accounting for sample size effects. Clonal species with few and heavy diaspores were most abundant, as well as early‐flowering species and those lacking dispersal structures. Local and regional range size were determined largely by habitat availability, while national range was positively affected by plant height and diaspore mass. Main conclusions Different processes determine the local density of species and their range size. Abundance within habitat patches appears to be related mainly to the species life histories, especially to their capacity for extensive clonal reproduction, whereas range size appears to be determined strongly by the availability of suitable habitat.     

Growth of ectomycorrhizal mycelia and composition of soil microbial communities in oak forest soils along a nitrogen deposition gradient

Deciduous forests may respond differently from coniferous forests to the anthropogenic deposition of nitrogen (N). Since fungi, especially ectomycorrhizal (EM) fungi, are known to be negatively affected by N deposition, the effects of N deposition on the soil microbial community, total fungal biomass and mycelial growth of EM fungi were studied in oak-dominated deciduous forests along a nitrogen deposition gradient in southern Sweden. In-growth mesh bags were used to estimate the production of mycelia by EM fungi in 19 oak stands in the N deposition gradient, and the results were compared with nitrate leaching data obtained previously. Soil samples from 154 oak forest sites were analysed regarding the content of phospholipid fatty acids (PLFAs). Thirty PLFAs associated with microbes were analysed and the PLFA 18:2ω6,9 was used as an indicator to estimate the total fungal biomass. Higher N deposition (20 kg N ha⁻¹ y⁻¹ compared with 10 kg N ha⁻¹ y⁻¹) tended to reduce EM mycelial growth. The total soil fungal biomass was not affected by N deposition or soil pH, while the PLFA 16:1ω5, a biomarker for arbuscular mycorrhizal (AM) fungi, was negatively affected by N deposition, but also positively correlated to soil pH. Other PLFAs positively affected by soil pH were, e.g., i14:0, a15:0, 16:1ω9, a17:0 and 18:1ω7, while some were negatively affected by pH, such as i15:0, 16:1ω7t, 10Me17:0 and cy19:0. In addition, N deposition had an effect on the PLFAs 16:1ω7c and 16:1ω9 (negatively) and cy19:0 (positively). The production of EM mycelia is probably more sensitive to N deposition than total fungal biomass according to the fungal biomarker PLFA 18:2ω6,9. Low amounts of EM mycelia covaried with increased nitrate leaching, suggesting that EM mycelia possibly play an important role in forest soil N retention at increased N input.     

Derivation of the short form of the Oral Health Impact Profile in Spanish (OHIP-EE-14)

doi: 10.1111/j.1741‐2358.2012.00613.x
Derivation of the short form of the Oral Health Impact Profile in Spanish (OHIP‐EE‐14) Background and Objective: The Oral Health Impact Profile is the most frequently used and validated of the Oral Health Quality of Life instruments. Several short versions have been developed; and a validation of the OHIP‐49 in Spanish has been published. The objective was to develop the short version of the Oral Health Impact Profile in Spanish (OHIP‐EE‐14). Methods: Cross‐sectional study. One hundred and thirty‐one persons aged ≥60 years attending a social centre for the elderly, residents of a nursing home and persons seeking dental care at a dental school in Mexico City were interviewed and examined. The validity of each of the 49 questions was evaluated, and, to construct the short version, 14 items were selected. The perceived need for dental treatment, number of teeth, presence of coronal caries, root caries, presence of dental plaque and utilisation of removable prosthesis were measured. Internal consistency, repeatability and discriminant validity were calculated. Results: The OHIP‐EE‐14 was reliable (Cronbach’s‐α = 0.918, ICC = 0.825). Significant associations were found between OHIP‐EE‐14 and the number of teeth and perceived need for dental treatment. Conclusions: The OHIP‐EE‐14 is a reliable and valid instrument and can be used in subjects aged 60 years and over from Mexico City.     

Edentulism and dental caries in Victorian nursing homes

doi: 10.1111/j.1741‐2358.2011.00510.x Edentulism and dental caries in Victorian nursing homes Objectives: The aim of this project was to investigate edentulism and dental caries in nursing home residents in Victoria, Australia. Background: The Australian population is ageing with a growing number of people living in nursing homes. These residents are at increased risk for dental caries, have more teeth present now than at any time in the past 50 years and often have difficulty maintaining adequate oral hygiene. Materials and methods: Clinical dental examinations were conducted at 31 nursing homes in Melbourne and regional Victoria between May 2005 and June 2006. A total of 510 residents were examined out of 1345 eligible participants. Socio‐demographic and medical history was collected via questionnaire. Results: Just over half of the residents were dentate (53.9%), and dentate residents had a mean of 14.4 teeth present and 2.66 untreated decayed teeth. Residents who required total assistance with oral hygiene had more decayed teeth and fewer filled teeth than residents who did not require assistance. Conclusions: Nursing home residents in Victoria are retaining an increasing number of natural teeth and have more tooth surfaces at risk for dental caries. Untreated dental caries was a significant problem for residents, particularly for those who are dependent on others for their daily oral hygiene care.     

The evaluation of oral health in stroke patients

doi: 10.1111/j.1741‐2358.2011.00505.x The evaluation of oral health in stroke patients Objective: As tooth loss has been suggested as a potential risk factor for stroke, oral examinations were carried out on stroke patients to review the oral condition of those patients. Method: The subjects were patients consecutively discharged from the recovery rehabilitation unit of Hiroshima City General Rehabilitation Center between April 2008 and December 2009. All patients were offered oral examination and 358 of 443 patients accepted. Patients receiving dental examination were divided into two groups: one group comprising stroke patients and the second, patients with other disorders. These two groups were then compared for the number of remaining teeth by age group. Results: Among the examined patients, the number of remaining teeth in stroke patients in their 50s and 60s was significantly lower than for patients in corresponding age groups (18.4 ± 9.4 vs. 24.5 ± 5.4 and 18.3 ± 9.2 vs. 22.2 ± 7.2, respectively, with p < 0.05 for both age groups) who were hospitalised for other conditions. In addition, the number of remaining teeth in stroke patients in their 50s was also significantly lower than the number reported in the Survey of Dental Diseases (24.1 ± 6.1; p < 0.05). Conclusion: The results of this study suggest an association between tooth loss and early occurrence of stroke.     

Relationship between nutritional status and tooth loss in an older population from Sri Lanka

doi: 10.1111/j.1741‐2358.2011.00518.x Relationship between nutritional status and tooth loss in an older population from Sri Lanka Objective: To determine the relationship between tooth loss and nutritional status in older individuals in Sri Lanka. Background: In developing countries, both the prevalence of malnutrition and oral disease are high among older individuals. Materials and methods: Four hundred and eighty subjects aged 60 years and above were selected to be included in the sample, of which 437 responded giving an overall response rate of 91%. Data were collected by means of an interviewer administered questionnaire, an oral examination and a physical examination to determine height and weight to calculate the body mass index (BMI). Results: Based on the WHO cut‐offs for BMI, 62, 20 and 18% of the sample were normal, under‐ and over‐weight, respectively. A multinomial logistic regression analysis with normal weight as the reference category revealed that missing teeth and denture status were associated with being underweight but not with being overweight. Conclusion: In older individuals, tooth loss is significantly associated with being underweight.     

Oral rehabilitation of severely worn dentition using an overlay for immediate re-establishment of occlusal vertical dimension

The aim of this study was to describe the treatment used in an elderly patient presenting with bruxism and dental erosion, with good gingival health and bone support, but with decreased occlusal vertical dimension (OVD). The oral rehabilitation of elderly patients presenting with bruxism in association with tooth erosion has been a great challenge for dentists. The loss of OVD, the presence of occlusal instability and the absence of an effective anterior guide due excessive dental wear, can damage stomatognathic system (SS) biology, the function and the aesthetics. In the first treatment stage, an overlay removable partial denture (ORPD) was fabricated for the immediate re-establishment of function and aesthetics. After a 2-month follow up, with the patient presenting no symptoms, a second rehabilitation stage was accomplished, with fixed and removable prostheses. Oral rehabilitation with an ORPD was able to re-establish the SS biology, but a correct diagnosis and treatment plan are essential for success. The ORPD is a non-invasive and reversible restoring modality for general dentists that allow the re-establishment of the patient's immediate aesthetics and function at low cost.