DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE.

Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.

Variation in Craniodental Pathologies Among Cercopithecoid Primates.

Pathologies of the skull and teeth are well documented for many human populations, but there are fewer studies of other primates. We contrast lesion prevalence and patterning among cercopithecoid primates and map variation onto socioecological variables. We compare craniodental lesions in six species: Nasalis larvatus (n = 54), Colobus polykomos (n = 64), Cercopithecus mitis (n = 65), Macaca fascicularis (n = 109), Theropithecus gelada (n = 13), and Papio anubis (n = 76). One of us (C.A.K.) evaluated each adult skull for multiple lesion types using standard criteria. We also tested for a relationship between lesion prevalence and cranial suture fusion (age proxy). We used nonparametric tests for sex and species differences as well as pathology co-occurrence in SPSS. Socioecological data come from previous studies. Sex differences in lesion prevalence were only detected in P. anubis. Within taxa, some lesion types co-occurred. In Macaca, the presence of caries was associated with several other lesion types. Pulp cavity exposure co-occurred with TMJ osteoarthritis in multiple taxa. Among taxa, male P. anubis had higher lesion prevalences, particularly related to the anterior dentition and facial trauma. Because we did not detect a relationship between suture fusion and lesion prevalence, we propose that craniodental lesions may also be influenced by socioecological variables such as group composition and ratio of fruit to leaves in the diet. Our findings suggest that pain from pulp cavity exposure and related dental infections may alter chewing biomechanics and contribute to onset of TMJ osteoarthritis in nonhuman primates, as seen in humans. Further, we suggest that higher lesion prevalence in male baboons is likely related to male-male competition. Skeletal lesion analysis provides useful insight into primate socioecology, particularly for rare or difficult-to-observe phenomena, and provides additional biological context for our own species.

Wnt signalling in oral and maxillofacial diseases.

Wnts include more than 19 types of secreted glycoproteins that are involved in a wide range of pathological processes in oral and maxillofacial diseases. The transmission of Wnt signalling from the extracellular matrix into the nucleus includes canonical pathways and noncanonical pathways, which play an important role in tooth development, alveolar bone regeneration, and related diseases. In recent years, with the in-depth study of Wnt signalling in oral and maxillofacial-related diseases, many new conclusions and perspectives have been reached, and there are also some controversies. This article aims to summarise the roles of Wnt signalling in various oral diseases, including periodontitis, dental pulp disease, jaw disease, cleft palate, and abnormal tooth development, to provide researchers with a better and more comprehensive understanding of Wnts in oral and maxillofacial diseases.

DENTAL DISEASES AND OTHER ORAL PATHOLOGIES OF CAPTIVE JAGUARS (PANTHERA ONCA) FROM BELIZE, CENTRAL AMERICA.

Dental and oral diseases are prevalent in many mammalian species including wild felids. Determining the dental and oral health status of captive animal populations can help establish preventive and therapeutic strategies, leading to improved welfare and conservation efforts. The aim of this study was to assess the prevalence of periodontal disease, endodontic disease, tooth resorption, and other clinically relevant dental and maxillofacial abnormalities in a population of captive jaguars (Panthera onca) using clinical, radiographic, and histopathological findings. Fifteen jaguars, ranging from young adult to geriatric, kept at a private zoo in Belize, Central America, had a detailed oral examination under general anesthesia between January 2015 and March 2019. Periodontitis was present in 3.8% (16/423) of examined teeth and 53.8% (7/13) of jaguars that underwent periodontal probing. Endodontic disease secondary to dentoalveolar trauma was found in 21.0% (89/423) of teeth in 73.3% (11/15) of animals. Tooth resorption, which has not been previously documented in jaguars, affected 1.4% (6/423) of teeth in 13.3% (2/15) of jaguars. Other abnormalities included metallic foreign material (gunshot) identified radiographically in 33.3% (5/15) of jaguars and nontraumatizing malocclusion in 9.1% (1/11) of jaguars that had occlusion evaluated. Much of the oral pathology identified in captive jaguars is suspected to arise from capture and/or captivity-associated behaviors, as suggested by gunshot around the oral cavity, fractures of rostral teeth (canine and incisor teeth), and abrasions consistent with cage-biting on canine teeth. Anesthetized oral examination-including full-mouth intraoral radiographs, periodontal probing, and charting-is recommended for jaguars with clinical signs of oral pain, as well as for routine systemic evaluation.

Making sense of medieval mouths: Investigating sex differences of dental pathological lesions in a late medieval Italian community.

OBJECTIVES: Bioarchaeological investigations of sex-based differences in the prevalence of dental pathological lesions, particularly caries, have drawn considerable attention, and out of this work, two dominant models have emerged. Traditionally, the first model interprets sex-related patterns in caries as a product of gendered differences in diet. A more recent model interprets a generally higher propensity for caries prevalence in females in light of reproductive ecology. To test the hypothesis that females have higher risk of caries in accordance with reproductive ecology, we examined and analyzed caries prevalence and other potentially synergistic oral pathological lesions in a late medieval (A.D. 1300-1500) Italian archaeological sample. MATERIALS AND METHODS: We examined sex- and age-related prevalence in caries and other oral pathological lesions in a late medieval Italian skeletal assemblage excavated from Villamagna consisting of 38 females and 37 males (n = 1,534 teeth). We examined age- and sex-related patterns in six dental traits: antemortem tooth loss, caries, calculus, periapical inflammation, tooth wear, and periodontitis. RESULTS: Significant age-related increases in antemortem tooth loss, caries, calculus, and tooth wear were observed in both males and females. However, there was a lack of expected sex differences in oral pathological lesions, with instead older males exhibiting significantly more antemortem tooth loss and corrected caries than females. DISCUSSION: Results are discussed in relation to the ethnohistoric context of medieval rural dietary practices as well as biomedical salivary literature, which suggest that dietary changes throughout the life course may have facilitated trade-offs that buffered females from higher rates of dental pathological lesions.

Growth response of dental tissues to developmental stress in the domestic pig (Sus scrofa).

OBJECTIVES: To compare relative response of enamel, dentin and bone to developmental stressors between attritional and catastrophic mortality assemblages of pigs. MATERIALS AND METHODS: Heads from 70 Sus scrofa of known sex, weight and age comprising an attritional sample of 50 sick pen (SP) pigs that died prematurely versus 20 control pigs slaughtered at 6 months (Catastrophic assemblage). Hard tissue changes (alveolar bone thinning), abnormal bone formation (Harris lines) and re-modeling (auditory bullae) were recorded. Areas and volumes of coronal enamel and dentin were recorded from microCT scans with Avizo 6.3 and Geomagic Wrap. RESULTS: Attritional and catastrophic assemblages are metrically indistinguishable. Ages at death and tissue measures in the SP pigs are differentially distributed, necessitating partition into developmental outcome cohorts. SP "late death" pigs are of lesser physiological maturity than expected, free of disease, with large dental tissue dimensions, comparable to "Controls". SP "early death" pigs have 5% less dentin and enamel and chronic bone infection. Older cohorts of the SP "early deaths" mortality assemblage show progressively reduced enamel. SP pigs show dental evidence of reduced bone mass in the maxilla. DISCUSSION: Bone, dentin and enamel tissues, each, respond distinctively to developmental stressors. Bone mass evinces malnutrition not disease. Both dental tissue reduction and abnormal bone formation link to chronic infection. Paradoxically, reduced dentin mass signals lower survivorship while reduced enamel signals enhanced survivorship. Meaningful comparison of Attritional and Catastrophic assemblages necessitates recognition of developmental outcome cohorts, stratified by age at death and physiological maturity, to reveal heterogeneity of survivorship, tissue measures and lesions.

Crypt fenestration enamel defects and early life stress: Contextual explorations of growth and mortality in Colonial Peru.

OBJECTIVES: This study provides a comprehensive analysis of crypt fenestration enamel defects (CFEDs) from the Eten and Mórrope communities, Colonial period (A.D. 1,530-1,750), Lambayeque Valley, Peru. The goal is to help clarify the role of these lesions as reflections of early life environments as well as relationships growth and survival at future ages. MATERIALS AND METHODS: CFED absence/presence was recorded in the mandibular canines of 105 individuals and 202 teeth. Defect prevalence was compared between the Eten and Mórrope sites using a proportions test. Femoral growth residuals were compared between CFED present and absent samples. Mortality risk was evaluated using Kaplan-Meier survival analysis. RESULTS: CFED frequencies at Eten and Mórrope were similar to previous studies. Greater frequencies of CFEDs were found at Eten compared to Mórrope. There was no association between skeletal growth and CFEDs. No differences in mortality were found between CFED present and absent individuals within each site. General survivorship at Eten was significantly greater than Mórrope. However, individuals without CFEDs at Eten had greater survivorship than those with and without CFEDs at Mórrope. Individuals with CFEDs at Eten had greater survivorship than those with CFEDs at Mórrope. These differences begin around 1.7 years. CONCLUSIONS: CFEDs may be associated with stress experience, but associations with growth and survivorship at later ages is context dependent. CFED prevalence is an ambiguous indicator of stress when used in the absence of mortality data, and even under those circumstances, appears limited by differences in local demography.

Hunter-gatherer dental pathology: Do historic accounts of Aboriginal Australians correspond to the archeological record of dental disease?

OBJECTIVES: Studies of hunter-gatherer oral pathology, particularly in Australia, often focus upon dental wear and caries or assume that historic studies of Aboriginal people reflect the precontact past. Consequently the range of population variation has been underestimated. In this paper dental pathology from human remains from Roonka are compared with a model of dental pathology derived from historic studies. The aim is to identify aspects of dental pathology indicative of regional or intra-population diversity. METHODS: Adult dentitions (n = 115) dating from the mid to late Holocene were recorded for the following conditions: dental wear, caries, periapical voids, calculus, periodontal disease and antemortem tooth loss. Statistical analysis was used to identify patterns of dental pathology and to identify causal relationships between conditions. RESULTS: Dental wear is marked while dental caries rates are extremely low. Other indications of dental pathology are uncommon (<7% of teeth affected). Temporal heterogeneity is apparent: there are 3 young adults with caries who died in the postcontact period. There is also a small group of middle age to old adults with disproportionate abscessing and pulp exposure who may represent temporal variation or heterogeneity in individual frailty. CONCLUSIONS: The results confirm dental wear as the major cause of dental pathology in this group and that, at a general level, historic accounts do correspond with this archeological sample. However, intra-sample heterogeneity is apparent while 2 dental conditions, calculus and periodontal disease, along with the pattern of sex differences deviate from expectation, demonstrating that to identify regional variation attention needs to be paid to the dentoalveolar complex as a whole.

Radiographic Assessment of Dental Pathology and Abnormalities in Dolphins.

This study proposes a simple standardized method for the production of analog X-ray images of dolphin teeth, and to explore its potential use as a complementary technique in the evaluation of dental pathology in small cetaceans. We investigated exposure times that produced the best results, and whether radiographs helped in the diagnosis of macroscopic abnormalities. Teeth of six species of dolphins (Delphinidae: Tursiops truncatus, Steno bredanensis, Sotalia guianensis, Delphinus sp., Stenella coeruleoalba, and Stenella frontalis) were X-rayed in an analog dental X-ray machine operating at 70 kVp and 7 mA. Intraoral size 2 standard films were used, and the focus-film distance was standardised at 35 cm. Those species with smaller teeth (total length 12-20 mm) had the best results when exposed for 0.3 seconds, while species with larger teeth (30-45 mm) had to be exposed for 0.4 seconds for their best result. Three independent examiners analysed all the images taken. The average pairwise percent agreement was 73% (Fleiss' Kappa = 0.229), suggesting fair agreement between examiners. Analog X-ray images produced were useful in complementing the diagnosis of dental pathology and abnormalities in dolphins, in addition to allowing the observation of internal details and lesion depths, which would not be possible with conventional macroscopic methods. The use of analog X-ray imaging is easily applicable to the study of dolphin teeth, with low operating costs and simple logistics compared to other non-destructive analytical approaches such as Micro-CT.

High altitude agriculture in the Titicaca basin (800 BCE-200 CE): Impacts on nutrition and disease load.

OBJECTIVES: This study investigates the biological impacts of sedentism and agriculture on humans living in the high altitude landscape of the Titicaca Basin between 800 BCE and CE 200. The transition to agriculture in other global areas resulted in increases in disease and malnutrition; the high altitude of the Titicaca Basin could have exacerbated this. Our objective is to test whether the high altitude of the Titicaca Basin created a marginal environment for early agriculturalists living there, reflected through elevated rates of malnutrition and/or disease. METHODS: To test this, we analyzed human remains excavated from seven archaeological sites on the Copacabana Peninsula for markers of diet and disease. These markers included dental caries, dental abscesses, cribra orbitalia, porotic hyperostosis, periosteal reactions, osteomyelitis, and linear enamel hypoplasia. RESULTS: Results showed that markers of diet did not support malnutrition or micronutrient deficiencies but instead, indicated a relatively diverse diet for all individuals. Markers of disease also did not vary significantly but were common, indicating circulation of pathogens or chronic bodily stress. CONCLUSIONS: We interpret these results as an indication that while diets remained nutritious, investment in the landscape exposed populations to issues of sanitation and disease. The high-altitude of the Titicaca Basin did not exacerbate the biological impacts of agriculture in terms of increased malnutrition. Additionally, disease load was likely related to problems faced by many sedentary groups as opposed to unique challenges posed by high altitude. In sum, despite the high elevation, the Titicaca Basin is not truly a marginal environment for humans.

Oral health considerations in anorexia and bulimia nervosa. 1. Symptomatology and diagnosis.

Eating disorders have captured the attention of medical and dental professionals as well as the public for decades and continue to raise concern today. The literature devoted to anorexia and bulimia highlights myriad psychological, systemic, and dental health complications. Dental practitioners are in a unique position to discover early manifestations of these disorders. The present article reviews anorexia and bulimia, summarizing telltale behavioral traits, systemic manifestations, and dental features to facilitate recognition and enable accurate diagnosis.

Establishing Apical Patency: To be or not to be?

INTRODUCTION: The apical portion of the root canal is very complex and challenging during endodontic treatment. Root canal preparation and obturation to the apical constriction may provide the best prognosis. Incomplete debridement, foramen transportation, and inadequate seal in the apical portion are considered to be responsible for treatment failure. The technique "apical patency" is considered as a way for maintaining the apical part the free of the debris by recapitulation, using a small K-file through the area of the apical foramen. This term was firstly proposed by Buchanan. In this technique, the smallest diameter file is set 1 mm longer than working length and recapitulated after each instrument to prevent packing of debris in the apical part. Apical patency has been found to be effective in achieving an apical seal with gutta-percha. Teeth prepared with a step back method and with maintained apical patency may show less leakage when obturated with cold lateral condensation technique. Data regarding the effect of apical patency on the healing of periapical tissue are very scarce, and it has been shown that the patency file has detrimental effect on the healing of periapical tissues in animal studies. However, using patency file in endodontic treatment is controversial and further studies are needed. The purpose of this article is to review the effect of using a patency file on the extrusion of root canal contents, the apical seal, postoperative pain, and healing of periapical tissues. Furthermore, the effect of establishing patency on reaching irrigation solutions to the apical portion of the canal and prognosis of root canal treatment are discussed. CLINICAL SIGNIFICANCE: Keywords: Apical patency, Apical seal, Apical transportation, Postoperative pain, Prognosis.

Diagnoses and Treatment of Dental Disorders in a Research Colony of Macaca fascicularis: A Case Series.

During daily routine oral examinations in a research colony of nonhuman primates (NHPs, Macaca fascicularis), a variety of oral-dental lesions were identified. A dental care program was established based on these findings. Based on the presence of dental clinical signs and their severity, 31 animals were triaged to be examined and treated by a veterinarian. Clinical examination consisted of visual inspection using a periodontal probe/explorer and full or partial mouth dental radiographs. Treatment was performed during the same procedure. Some animals had a follow-up examination including radiographs months later. Four common dental diseases were diagnosed: periodontal disease, caries, tooth fracture, and tooth attrition. Less frequent were dental abscess, enamel hypomineralization, gingival hyperplasia, hypercementosis, tooth luxation, tooth dysplasia, root resorption, abrasion. Less severe periodontal disease was treated conservatively. If severely affected, teeth were extracted. Well-circumscribed caries without endodontic involvement were treated by composite restoration. Teeth with extensive caries and pulp involvement were extracted. Teeth with exposed pulp were treated via extraction or orthograde root canal treatment. In this case series, 27 (87%) of 31 NHPs exhibited at least 1 moderate to severe dental lesion that required treatment. The presumable improvement in welfare and weight of oral/dental lesions for the overall health status in research NHPs encourages us to continue this program prospectively.

Comparative analysis of dentognathic pathologies in the Dmanisi mandibles.

OBJECTIVES: Due to the scarcity of the fossil record, in vivo changes in the dentognathic system of early Homo are typically documented at the level of individual fossil specimens, and it remains difficult to draw population-level inferences about dietary habits, diet-related activities and lifestyle from individual patterns of dentognathic alterations. The Plio-Pleistocene hominin sample from Dmanisi (Georgia), dated to 1.77 million years ago, offers a unique opportunity to study in vivo changes in the dentognathic system of individuals belonging to a single paleodeme of early Homo. MATERIALS AND METHODS: We analyze dentognathic pathologies in the Dmanisi sample, and in comparative samples of modern Australian and Greenlander hunter-gatherer populations, applying clinical protocols of dentognathic diagnostics. RESULTS: The Dmanisi hominins exhibit a similarly wide diversity and similar incidence of dentognathic pathologies as the modern human hunter-gatherer population samples investigated here. Dmanisi differs from the modern population samples in several respects: At young age tooth wear is already advanced, and pathologies are more prevalent. At old age, hypercementosis is substantial. CONCLUSIONS: Results indicate that dentognathic pathologies and disease trajectories are largely similar in early Homo and modern humans, but that the disease load was higher in early Homo, probably as an effect of higher overall stress on the dentognathic system. Am J Phys Anthropol 160:229-253, 2016. © 2016 Wiley Periodicals, Inc.

Platelet concentrates for revitalization of immature necrotic teeth: a systematic review of the clinical studies.

This systematic review aimed at determining the effectiveness of autologous platelet concentrate (APC) in the treatment of immature necrotic teeth. An electronic search was performed on MEDLINE, Embase, Scopus, SciELO, Lilacs, CENTRAL. Comparative clinical studies were included, in which APC was tested for pulp regeneration and radicular development. Selected articles underwent risk-of-bias assessment. Clinical and radiographic outcomes were considered. Three randomized parallel studies and one split-mouth case series were included. One study had low risk of bias and three studies had high risk. A total of 61 immature necrotic teeth were treated in 56 patients. Follow-up ranged between 12 and 18 months. All studies used platelet-rich plasma (PRP) in the test group, and one also used platelet-rich fibrin (PRF). After treatment, all teeth of control and experimental groups remained asymptomatic for the entire study duration. Only one study reported response to cold and electric pulp test, showing not significantly better outcomes for the test group. Similarly, periapical healing and apical closure were improved in the group treated with APC although statistical significance was not achieved (P = 0.08 and P = 0.06, respectively), probably due to the limited sample size. The teeth treated with PRP achieved significantly better thickening of the dentin walls (P = 0.01), and root lengthening (P = 0.001) than control teeth. Despite the potential effectiveness of APC in promoting root development of necrotic immature teeth, scarce evidence exists regarding this subject. In the studies evaluated in this review, platelet concentrates showed promising results that warrant further investigation.

Review of the dental implications of X-linked hypophosphataemic rickets (XLHR).

OBJECTIVES: The aim of this article was to review the dental implications of X-linked hypophosphataemic rickets (XLHR) and to provide suggestions regarding the dental treatment of these patients. MATERIALS AND METHODS: The following search items "x-linked hypophosphataemia, hypophosphataemic rickets, vitamin D-resistant rickets" were used for literature search. Only full-text articles were analysed and summarized to get an overview of the different treatments and outcomes of hypophosphataemic patients. RESULTS: Radiographically, very large pulp chambers with an abnormally high pulp volume/tooth volume ratio, suggesting taurodontism, are often evident. The affected teeth are characterised by a thin enamel layer and dentinal defects. The gender distribution of hypophosphataemic patients is almost equal, but postpubertary males seem to show a trend to develop more severe dental symptoms of the disease. Abscesses without any signs of dental caries or trauma are frequent findings. The most often affected teeth are incisors followed by molars and premolars. CONCLUSIONS: Treatment options include frequent dental examination, application of topical fluoride varnish and sealing of pits and fissures to prevent microbial invasion that may result in pulpitis and further endodontic complications. CLINICAL RELEVANCE: X-linked hypophosphataemic rickets is associated with marked structural alterations of dental hard tissues and the development of multiple abscesses and sinus tracts of dental origin. Therefore, profound knowledge of the various dental implications of XLHR is required to provide these patients with the best possible treatment options.

DENTAL LESIONS IN THE LOWLAND TAPIR (TAPIRUS TERRESTRIS).

Dental ailments, mandibular swelling, and dentoalveolar abscesses are common in tapirs, but knowledge about prevalence or etiology of these lesions in the Tapiridae family in general, and in lowland tapirs (Tapirus terrestris) in particular, is scarce. A recent study identified resorptive lesions of unknown etiology as a common problem in the Malayan tapir (Tapirus indicus). In order to investigate the type and prevalence of dental lesions occurring in lowland tapirs, and to compare these with findings with the Malayan tapir, skulls and teeth from 46 deceased lowland tapirs were visually and radiographically examined. The specimens were divided into subpopulations according to age (juveniles, young adults, adults) and origin (free-range or captive). Dental lesions were identified in 24% (11/46) of the study population. The most common pathologic findings were complicated dental fractures with associated periapical reaction (15%) and periapical reactions of various degrees without associated detectable dental pathology (13%). All these lesions likely originated from dental trauma. As in Malayan tapirs, juveniles had significantly fewer lesions than adults. This study shows that dental lesions present frequent problems for lowland tapirs, occurring both in captive and in free-ranging individuals, and indicates that increasing age should be considered a risk factor for the development of these lesions. Notably, the predominant dental problems in lowland tapirs and Malayan tapirs are not the same.

[THE INTERDEPENDENCE BETWEEN SMOKING, ALCOHOL, TOOTH PATHOLOGY AND PREVALENCE OF HELICOBACTER PYLORI AMONG ETHNIC GROUPS IN KYRGYZSTAN].

The main aim was to study the ethnic and social characteristics of the prevalence of certain risk factors among Kyrgyz ethnic population infected with Helicobacter pylori without clinical signs of the disease of upper gastrointestinal tract. The study involved 116 healthy individuals (57 and 49 Kyrgyz, Russian) who were tested on H. pylori infection, taking into account risk factors such as smoking, alcohol consumption, low or serious teeth damage. The identified H.pylori infection was independent from ethnic affiliation. Significant relation between absence or high damage of the teeth and H. pylori contamination was revealed in surveyed Kyrgyz group.

Gearbox tooth cut fault diagnostics using acoustic emission and vibration sensors--a comparative study.

In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

[Alterations in nails and teeth as a clue for genodermatoses]. / Anomalien der Nägel und Zähne als Schlüssel für die Diagnose von Genodermatosen.

BACKGROUND: There are about 10,000 monogenic diseases and around 30% demonstrate alterations in the skin and its appendages. As there are so many genetic different skin diseases, clear diagnosis is often very difficult. AIM: The goal of this review is to give the clinicians some key features on nails and teeth which might help to identify rare genodermatoses. DISCUSSION: In the daily work genodermatoses manifest more commonly as incomplete or oligosymptomatic syndromes than as complete symptom complexes. To diagnose a rare disorder in such situations, a knowledge of key features which are characteristic for a genodermatoses is essential, so that a diagnosis can be advanced and the underlying gene defect identified. Changes in nails and teeth sometimes may be useful as diagnostic key features. Both structures originate from ectoderm and therefore they often appear in combination in diseases with major ectodermal malformations. Enamel defects resembling the lines of Blaschko are highly suggestive for focal dermal hypoplasia, even if other important signs and symptoms are missing. Enamel defects combined with gingival fibromas are highly suggestive for tuberous sclerosis. On the other side, triangular lunulae with malformation and dystrophy of the nail plate suggests nail-patella syndrome.