Explore the vast range of titles available.

Hypotonia, ataxia, developmental delay, and tooth enamel defect syndrome (HADDTS) is an extremely rare autosomal dominant genetic disease caused by disruptive pathogenic variants in CTBP1. There are merely 12 cases reported to have pathogenic variants in the CTBP1 gene. Here, we report the first case with HADDTS in the Middle-Eastern population. In the present study, whole-exome sequencing was deployed to identify the variant(s) causing this condition. Subsequently, Sanger sequencing was performed to confirm the variant. The clinical evaluation of the patient is written according to the thoroughly carried out examinations and clinical investigations. A novel single frameshift pathogenic variant in CTBP1 (NM_001328.3:c.1315_1316delCA, p.Gln439ValfsTer84) was identified as the cause for HADDTS in the proband. Our findings enhance the knowledge of poorly studied CTBP1. The newly reported patient is phenotypically different in comparison to the previously reported cases. He has no sign of hypotonia, difficulty in walking or standing.

The objective of this article was to carry out a systematic review of the literature to determine the different therapeutic uses of chitosan-based hydrogels and their uses in dental therapy, as well as the modification and improvement of dental materials to promote research related to chitosan and its incorporation into dentistry as an adjunct or replacement in some dental treatments. Chitosan is a natural polymer obtained from the deacetylation of chitin, a polysaccharide abundant in nature, which, due to its biocompatibility, high biodegradability, non-antigenicity, and its ease of acquisition, has attracted biomedical interest, including in dentistry. Recent studies have shown that chitosan can be integrated into dental materials to obtain remineralizing effects, such as for antimicrobial agents, osteogenic agents, and pulp regeneration treatment. A bibliographic search was carried out in PubMed from 2018 to 2023. The results showed a wide range of uses for chitosan in the dental field, particularly its use as a remineralizing agent for tooth enamel; It has also been used in tissue regeneration mainly because of its osteogenic activity, as an antimicrobial agent, and as a vehicle for the application of medications. The use of chitosan as a nanobiomaterial is an interesting topic, since chitosan shows potential for new dental materials, either as an active ingredient or as an adjuvant vehicle for other materials. El objetivo de este artículo fue realizar una revisión sistemática de la literatura para determinar los diferentes usos terapéuticos de los hidrogeles de quitosano y su enfoque en la terapia odontológica, así como la modificación y mejoramiento de materiales dentales para promover investigaciones relacionadas con el quitosano y su incorporación a el área dental como coadyuvante o sustituto en algunos tratamientos odontológicos. El quitosano es un polímero natural obtenido de la desacetilación de la quitina, un polisacárido abundante en la naturaleza, que por sus características ha despertado el interés de la biomedicina. La odontología no es ajena a este interés, pues estudios recientes han demostrado que el quitosano puede integrarse a materiales dentales para obtener efectos remineralizantes, como agentes antimicrobianos, agentes osteogénicos, en tratamientos de regeneración pulpar, entre otros. Se realizó una búsqueda bibliográfica en PubMed, Scopus y Google Scholar desde 2018 hasta 2023. Los resultados mostraron una amplia gama de usos del quitosano en el ámbito odontológico. Lo que más destaca es el uso como agente remineralizante del esmalte dental; también fue utilizado en la regeneración de tejidos principalmente por su actividad osteogénica, como agente antimicrobiano, como vehículo para la aplicación de medicamentos, entre otros. El uso del quitosano como nanobiomaterial es un tema interesante, ya que por sus características, el quitosano muestra potencial para nuevos materiales dentales ya sea como ingrediente activo o como vehículo coadyuvante de otros materiales.

High-resolution scanning transmission electron microscopy (STEM) images of human tooth enamel crystals, mainly in the high-angle annular dark-field (STEM-HAADF) mode, are presented in this work along the [1000], [10-11]. and [1-210] directions. These images allow knowing some structural details at the nanometric level of the human tooth enamel crystals and of the central dark line (CDL) observed at their centers. The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) images of the CDL showed the Fresnel contrast. In the STEM bright-field (STEM-BF) and annular-dark-field (STEM-ADF) images, the CDL was observed as an unstrain hydroxyapatite (HAP)-like zone but surrounded by a strained zone. In the STEM-HAADF images, the CDL appeared with a weak contrast, and its contrasts’ thickness was registered between 3 and 8 Å. The arrangement obtained in the STEM-HAADF images by identifying the bright points with the Ca atoms produced the superposition of the HAP atomic sites, mainly along the [0001] direction. The findings provide further information on the structure details at the center of enamel crystals, which favors the anisotropic carious dissolution at the CDL.

•Carbon and oxygen isotope analyses are conducted on Japanese tooth-enamel samples.•The resultant data is compared against data for US teeth from a similar study.•Logistic regression is used to differentiate between Japanese and US data.•This approach can be used to discriminate between Japanese and US war dead. Stable isotope analysis has undergone rapid development in recent years and yielded significant results in the field of forensic sciences. In particular, carbon and oxygen isotopic ratios in tooth enamel obtained from human remains can provide useful information for the crosschecking of morphological and DNA analyses and facilitate rapid on-site prescreening for the identification of remains. This study analyzes carbon and oxygen isotopic ratios in the tooth enamel of Japanese people born between 1878 and 1930, in order to obtain data for methodological differentiation of Japanese and American remains from the Second World War. The carbon and oxygen isotopic ratios in the tooth enamel of the examined Japanese individuals are compared to previously reported data for American individuals (born post WWII), and statistical analysis is conducted using a discrimination method based on a logistic regression analysis. The discrimination between the Japanese and US populations, including Alaska and Hawaii, is found to be highly accurate. Thus, the present method has potential as a discrimination technique for both populations for use in the examination of mixed remains comprising Japanese and American fallen soldiers.

Tooth enamel is the outer covering of tooth crowns, the hardest material in the mammalian body, yet fracture resistant. The extremely high content of 95 wt% calcium phosphate in healthy adult teeth is achieved through mineralization of a proteinaceous matrix that changes in abundance and composition. Enamel-specific proteins and proteases are known to be critical for proper enamel formation. Recent proteomics analyses revealed many other proteins with their roles in enamel formation yet to be unraveled. Although the exact protein composition of healthy tooth enamel is still unknown, it is apparent that compromised enamel deviates in amount and composition of its organic material. Why these differences affect both the mineralization process before tooth eruption and the properties of erupted teeth will become apparent as proteomics protocols are adjusted to the variability between species, tooth size, sample size and ephemeral organic content of forming teeth. This review summarizes the current knowledge and published proteomics data of healthy and diseased tooth enamel, including advancements in forensic applications and disease models in animals. A summary and discussion of the status quo highlights how recent proteomics findings advance our understating of the complexity and temporal changes of extracellular matrix composition during tooth enamel formation.

ABSTRACT Amelogenesis imperfecta (AI) is a condition of genetic origin that alters the structure of tooth enamel. AI may exist in isolation or associated with other systemic conditions as part of a syndromic AI. Our goal is to describe in detail the genes involved in syndromic AI, the proteins encoded by these genes, and their functions according to current scientific evidence. An electronic literature search was carried out from the year 2000 to December 2017, pre-selecting 1,573 articles, 40 of which were analyzed and discussed. The results indicate that mutations in 12 genes are responsible for syndromic AI: DLX3, COL17A1, LAMA3, LAMB3, FAM20A, TP63, CNNM4, ROGDI, LTBP3, FAM20C, CLDN16, CLDN19. These genes participate in the coding of proteins involved in phosphorylation, ion exchange, and production and degradation of the constituent elements of the mineral and organic phase of tooth enamel. The scientific evidence confirms that AI can be part of the syndrome and requires special attention from the medical-dental community.

The assignment of biological sex to archaeological human skeletons is a fundamental requirement for the reconstruction of the human past. It is conventionally and routinely performed on adults using metric analysis and morphological traits arising from postpubertal sexual dimorphism. A maximum accuracy of ∼95% is possible if both the cranium and os coxae are present and intact, but this is seldom achievable for all skeletons. Furthermore, for infants and juveniles, there are no reliable morphological methods for sex determination without resorting to DNA analysis, which requires good DNA survival and is time-consuming. Consequently, sex determination of juvenile remains is rarely undertaken, and a dependable and expedient method that can correctly assign biological sex to human remains of any age is highly desirable. Here we present a method for sex determination of human remains by means of a minimally destructive surface acid etching of tooth enamel and subsequent identification of sex chromosome-linked isoforms of amelogenin, an enamel-forming protein, by nanoflow liquid chromatography mass spectrometry. Tooth enamel is the hardest tissue in the human body and survives burial exceptionally well, even when the rest of the skeleton or DNA in the organic fraction has decayed. Our method can reliably determine the biological sex of humans of any age using a body tissue that is difficult to cross-contaminate and is most likely to survive. The application of this method will make sex determination of adults and, for the first time, juveniles a reliable and routine activity in future bioarcheological and medico-legal science contexts.

The outstanding mechanical and chemical properties of dental enamel emerge from its complex hierarchical architecture. An accurate, detailed multiscale model of the structure and composition of enamel is important for understanding lesion formation in tooth decay (dental caries), enamel development (amelogenesis) and associated pathologies (e.g., amelogenesis imperfecta or molar hypomineralization), and minimally invasive dentistry. Although features at length scales smaller than 100 nm (individual crystallites) and greater than 50 μm (multiple rods) are well understood, competing field of view and sampling considerations have hindered exploration of mesoscale features, i.e., at the level of single enamel rods and the interrod enamel (1 to 10 μm). Here, we combine synchrotron X-ray diffraction at submicrometer resolution, analysis of crystallite orientation distribution, and unsupervised machine learning to show that crystallographic parameters differ between rod head and rod tail/interrod enamel. This variation strongly suggests that crystallites in different microarchitectural domains also differ in their composition. Thus, we use a dilute linear model to predict the concentrations of minority ions in hydroxylapatite (Mg2+ and CO₃2−/Na⁺) that plausibly explain the observed lattice parameter variations. While differences within samples are highly significant and of similar magnitude, absolute values and the sign of the effect for some crystallographic parameters show interindividual variation that warrants further investigation. By revealing additional complexity at the rod/interrod level of human enamel and leaving open the possibility of modulation across larger length scales, these results inform future investigations into mechanisms governing amelogenesis and introduce another feature to consider when modeling the mechanical and chemical performance of enamel.

The ESR radiation dosimetric properties of tooth enamel samples from cows and goats were investigated and compared with those of human samples. Samples were prepared first mechanically, and then chemically. The study results showed that the native signals from cow and goat samples were weaker than those from human samples; the radiation sensitivities for cow and goat samples were very close to those of human tooth enamel samples. These results indicated that cow and goat teeth could be alternative materials for radiation dose estimation.

Objectives This study evaluated the adhesion and whitening effects of a combination of P11-4 self-assembling peptide and hydroxyapatite (peptide-HAP) on bovine enamel. Methods Forty-six caries-free bovine teeth were selected, and 40 teeth were randomly allocated to one of five groups ( n = 8). First, the effects of application frequency, exposure time, and storage in saliva on the whitening effects of an experimental low-concentrated peptide-HAP suspension (0.5 wt% HAP; Curodont, Credentis) were evaluated and compared with a commercial bleaching agent (VivaStyle Paint on Plus, VS, Ivoclar Vivadent). Tooth color was measured using a spectrophotometer (Gretag MacBeth), and color changes ΔE were statistically analyzed. Second, the effects of peptide-HAP concentration (low versus high: 6.25% HAP; Curodont Protect), and its interactions with saliva and postapplication restaining, were investigated. Third, enamel surfaces ( n = 2) were treated with low concentration peptide-HAP and high-concentration peptide-HAP in polymeric and monomeric forms (Curodont Protect & Curodont Repair, Credentis) and analyzed by SEM. Results The Δ E of the low-concentration peptide-HAP suspension did not differ from that of VS. Application frequency, exposure time, and storage in saliva did not have any significant impact on whitening efficacy of the peptide-HAP suspension. Increasing the concentration of the suspension did not promote overall Δ E . SEM observations confirmed the presence of the newly generated peptide and HAP on the enamel surface. Conclusions The peptide-HAP suspension is a mild tooth whitener, and the adhesion of peptide-HAP to enamel is concentration dependent. Clinical relevance This peptide-HAP suspension is effective in offsetting discoloration caused by restaining after treatment.