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In many adult tissues, mesenchymal stem cells (MSCs) are closely associated with perivascular niches and coexpress many markers in common with pericytes. The ability of pericytes to act as MSCs, however, remains controversial. By using genetic lineage tracing, we show that some pericytes differentiate into specialized tooth mesenchyme-derived cells—odontoblasts—during tooth growth and in response to damage in vivo. As the pericyte-derived mesenchymal cell contribution to odontoblast differentiation does not account for all cell differentiation, we identify an additional source of cells with MSC-like properties that are stimulated to migrate toward areas of tissue damage and differentiate into odontoblasts. Thus, although pericytes are capable of acting as a source of MSCs and differentiating into cells of mesenchymal origin, they do so alongside other MSCs of a nonpericyte origin. This study identifies a dual origin of MSCs in a single tissue and suggests that the pericyte contribution to MSC-derived mesenchymal cells in any given tissue is variable and possibly dependent on the extent of the vascularity.

Teeth are biological structures with a high degree of hardness, density, calcification, and capacity to adapt to extrinsic factors at physical, biological, and physiological levels. Subsequently, they resist for a longer period in deteriorating environmental conditions. With dental analysis, it is possible to acquire biographical data about a person. The aim of this scoping review was to identify publications using human teeth tissues to estimate sexual dimorphism. The scoping review was carried out in the following databases: Jstor, Scielo, Science Direct, PubMed, and Scopus, using ten search strategies in English and guaranteeing completeness and reproducibility of the phases stipulated in the PRISMA guide. 143 studies on sexual dimorphism based on dental tissue traits were included, of which 40.6% (n = 58) were done in Asia and 27.2% (n = 39) in America. 80% of the studies (equivalent to 114 articles) focused their observations and measurements on the dental crown; 4.2% in enamel, dentin, and pulp together; 3.5% in dental pulp; 2.1% in the entire tooth; 2.8% in enamel, root, and the enamel-cementum junction, and only 0.7% in dentin and pulp. In addition, 92.3% of the studies used metric methods, while only 4.9% and 2.8% used biochemical and non-metric method respectively. For sexual dimorphism establishment, enamel has been the most analyzed dental tissue in permanent canines and molars mainly. Likewise, the most widely and accurately used methods for this purpose are the metrics, with the odontometry as the most implemented (intraoral or by using dental plaster models, digital scanning or software) with prediction percentages ranging from 51% to 95.9%. In contrast to biochemical methods, that can achieve the highest precision (up to 100%), the non-metric methods, to a less extent, reported prediction percentages of 58%. •Canines and permanent molars are the most dimorphic teeth.•Odontometry, a metric method, is the most employed to assess sexual dimorphism.•51% to 95.9% of sex estimation accuracy can be achieved when using odontometry.•Biochemical methods are the most recommended for highly accurate sex estimation.•Combining artificial intelligence and metric methods offers precise sex estimation.

Dental pain often arises from the compromised integrity of the tooth pulp due to dental injury or caries. The dentin–pulp complex has long been considered to be central to the unique biology of dental pain. Most trigeminal ganglion afferents projecting into tooth pulp are myelinated neurons, which lose their myelination at the site of peripheral dentin innervation. The pulpal afferents likely combine multiple internal and external stimuli to mediate nociception and maintain pulp homeostasis. Transient receptor potential (TRP) ion channels in neurons and odontoblasts, along with mechanosensitive ion channels such as Piezo, form a key molecular hub for pulpal nociception by sensing thermal, chemical, and hydrodynamic stimuli. Among these, TRP vanilloid 1 (TRPV1) mediates nociception and the release of calcitonin-gene-related peptides (CGRPs), while TRP canonical 5 (TRPC5) mediates cold pain. TRP melastatin 8 (TRPM8) mediates the transduction of hyperosmotic stimuli. Pulpitis elevates endogenous TRPV1 and TRPA1 agonists, while inflammatory mediators sensitize TRP channels, amplifying pain. CGRP recruits immune cells and promotes bacterial clearance and reparative dentinogenesis, yet the roles of TRP channels in these processes remain unclear. Future studies should use advanced multi-omics and in vivo or organotypic models in animal and human teeth to define TRP channel contributions to pain, immune responses, and regeneration. Understanding neuronal and non-neuronal TRP channel interactions and their integration with other ion channels may enable novel analgesic and regenerative strategies in dentistry.

Age-at-death estimation is pivotal in the identification of unknown human decedents in forensic medicine. The pulp/tooth area ratio (PAR) method, assessing pulp cavity size as a marker of secondary dentine apposition, is widely utilised for adult age estimation. Despite extensive evaluation of this technique, the influence of image type and enamel area inclusion on method accuracy is insufficiently explored. The present study evaluated the PAR method’s applicability using maxillary canines from a South African cadaveric sample, examining reliability, sex bias, and accuracy across different image types and enamel area considerations. An observational, cross-sectional study design was followed. Fifty-two adult maxillary canines were radiographed, sectioned, and analysed using stereomicroscopy. Labiolingual and mesiodistal periapical radiographs, alongside labiolingual stereomicroscopic tooth section images, were analysed using ImageJ to calculate PARs. Age estimation linear regression models were developed for each image type, with and without enamel area inclusion. Models were compared for performance and accuracy using best-subsets regression and cross-validation analyses. Results indicated that the PAR method is a reliable, sex-independent technique, providing relatively accurate age-at-death estimates for South African adults. Image type significantly influenced accuracy, with tooth section images exhibiting the best/lowest error values, followed by labiolingual and mesiodistal radiographs, respectively. Exclusion of enamel area consistently enhanced model performance across all image types. This study contributes valuable data to the underexplored field of dental age estimation techniques for South African adults, highlighting optimal approaches when applying the PAR method to maxillary canines. Additionally, it introduces a refined stereomicroscopic technique, augmenting and enhancing existing practices.

•The present study was undertaken with an aim to evaluate reliability of dental age assessment through two different methods for adults i.e. tooth coronal index and pulp/tooth ratio using digital panoramic radiographs and also to compare the methods for their accuracy in age determination.•Digital panoramic radiographs of 180 subjects were analyzed of which 82 were males and 98 were females.•Both PCTHR and TCI correlated negatively with chronological age. PCTHR showed slightly higher negative correlation and proved as a better tool for age estimation than TCI. Assessment of an age of an individual whether living or dead through teeth is one of the most reliable and simple method to calculate age than skeletal remains especially when they are in poor conditions. The study was carried out with aim of (i) to evaluate reliability of dental age assessment through two different methods for adults i.e. tooth coronal index and pulp/tooth ratio using digital panoramic radiographs and (ii) to compare these methods for their accuracy in age determination. The digital panoramic radiographs of 180 subjects of Chhattisgarh aged 15–70 years were selected for the study. The measurements were performed on the JPEG images of selected panoramic radiographs by using Adobe Acrobat 7.0 professional software. For tooth coronal index (TCI), height of the crown i.e. coronal height (CH) and the height of the coronal pulp cavity i.e. coronal pulp cavity height (CPCH) of mandibular second premolars and first molars was measured in millimeter (mm) and then TCI was calculated for each tooth and calculated age was compared with chronological age. For pulp/tooth ratio, the measurements of pulp chamber height (PCH) and crown root trunk height (CRTH) were performed on the mandibular first and second molar teeth, the pulp chamber crown root trunk height ratios (PCTHR) of selected tooth were calculated. The acquired data were subjected to Pearson correlation test, unpaired t test and Analysis of Variance (ANOVA) analysis. Results suggested that TCI (mandibular first molar r=−0.178), second premolar (r=−0.187) and PCTHR(mandibular first molar r=−0.921, second molar r=−0.901) correlated negatively with chronological age suggesting decrease in size of pulp cavity. Mandibular first molar was found to be most reliable tooth to estimate dental age. The study showed that both PCTHR and TCI have negative association with chronological age. PCTHR showed slightly higher negative correlation and proved as a better tool for age estimation than TCI. Statistically significant differences were observed between chronological and calculated age by both methods thus emphasizing the need for future clinical trials.

Dental pulp stem cells (DPSCs) are responsible for maintaining pulp structure and function after pulp injury. DPSCs migrate directionally to the injury site before differentiating into odontoblast-like cells, which is a prerequisite and a determinant in pulp repair. Increasing evidence suggests that sensory neuron-stem cell crosstalk is critical for maintaining normal physiological functions, and sensory nerves influence stem cells mainly by neuropeptides. However, the role of sensory nerves on DPSC behaviors after pulp injury is largely unexplored. Here, we find that sensory nerves released significant amounts of calcitonin gene-related peptide (CGRP) near the injury site, acting directly on DPSCs via receptor activity modifying protein 1 (RAMP1) to promote collective migration of DPSCs to the injury site, and ultimately promoting pulp repair. Specifically, sensory denervation leads to poor pulp repair and ectopic mineralization, in parallel with that DPSCs failed to be recruited to the injury site. Furthermore, in vitro evidence shows that sensory nerve-deficient microenvironment suppressed DPSC migration prominently among all related behaviors. Mechanistically, the CGRP-Ramp1 axis between sensory neurons and DPSCs was screened by single-cell RNA-seq analysis and immunohistochemical studies confirmed that the expression of CGRP rather than Ramp1 increases substantially near the damaged site. We further demonstrated that CGRP released by sensory nerves binds the receptor Ramp1 on DPSCs to facilitate cell collective migration by an indirect co-culture system using conditioned medium from trigeminal neurons, CGRP recombinant protein and antagonists BIBN4096. The treatment with exogenous CGRP promoted the recruitment of DPSCs, and ultimately enhanced the quality of pulp repair. Targeting the sensory nerve could therefore provide a new strategy for stem cell-based pulp repair and regeneration.

One of the most studied class of non-coding RNAs is microRNAs (miRNAs) which regulate more than 60% of human genes. A network of miRNA gene interactions participates in stem cell self-renewal, proliferation, migration, apoptosis, immunomodulation, and differentiation. Human pulp tissue-derived stem cells (PSCs) are an attractive source of dental mesenchymal stem cells (MSCs) which comprise human dental pulp stem cells (hDPSCs) obtained from the dental pulp of permanent teeth and stem cells isolated from exfoliated deciduous teeth (SHEDs) that would be a therapeutic opportunity in stomatognathic system reconstruction and repair of other damaged tissues. The regenerative capacity of hDPSCs and SHEDs is mediated by osteogenic, odontogenic, myogenic, neurogenic, angiogenic differentiation, and immunomodulatory function. Multi-lineage differentiation of PSCs can be induced or inhibited by the interaction of miRNAs with their target genes. Manipulating the expression of functional miRNAs in PSCs by mimicking miRNAs or inhibiting miRNAs emerged as a therapeutic tool in the clinical translation. However, the effectiveness and safety of miRNA-based therapeutics, besides higher stability, biocompatibility, less off-target effects, and immunologic reactions, have received particular attention. This review aimed to comprehensively overview the molecular mechanisms underlying miRNA-modified PSCs as a futuristic therapeutic option in regenerative dentistry.

Chondroitin sulfate proteoglycan (CSPG), one of the major extracellular matrices, plays an important part in organogenesis. Its core protein and chondroitin sulfate (CS) chain have a specific biological function. To elucidate the role of CS in the developmental and healing process of the dental pulp, we performed an experimental tooth replantation in CS N-acethylgalactosaminyltransferase-1 (T1) gene knockout (KO) mice. We also performed cell proliferation assay and qRT-PCR analysis for the WT and T1KO primary dental pulp cells using T1-siRNA technique and external CS. During tooth development, CS was diffusely expressed in the dental papilla, and with dental pulp maturation, CS disappeared from the differentiated areas, including the odontoblasts. In fully developed molars, CS was restricted to the root apex region colocalizing with Gli1-positive cells. In the healing process after tooth replantation, CD31-positive cells accumulated in the CS-positive stroma in WT molars. In T1KO molars, the appearance of Ki67- and Gli1-positive cells in the dental pulp was significantly fewer than in WT molars in the early healing stage, and collagen I-positive reparative dentin formation was not obvious in T1KO mice. In primary culture experiments, siRNA knockdown of T1 gene significantly suppressed cell proliferation in WT dental pulp cells, and the mRNA expression of cyclin D1 and CD31 was significantly upregulated by external CS in T1KO dental pulp cells. These results suggest that CS is involved in the cell proliferation and functional differentiation of dental pulp constituent cells, including vascular cells, in the healing process of dental pulp tissue after tooth injury.

Different stem cell–based strategies, especially induced pluripotent stem cells (iPSCs), have been exploited to regenerate teeth or restore biological and physiological functions after tooth loss. Further research is needed to establish an optimized protocol to effectively differentiate human iPSCs (hiPSCs) into dental epithelial cells (DECs). In this study, various factors were precisely modulated to facilitate differentiation of hiPSCs into DECs, which are essential for the regeneration of functional teeth. Embryoid bodies (EBs) were formed from hiPSCs as embryo-like aggregates, retinoic acid (RA) was used as an early ectodermal inducer, and bone morphogenic protein 4 (BMP4) activity was manipulated. The characteristics of DECs were enhanced and preserved after culture in keratinocyte serum-free medium (K-SFM). The yielded cell population exhibited noticeable DEC characteristics, consistent with the expression of epithelial cell and ameloblast markers. DECs demonstrated odontogenic abilities by exerting an inductive effect on human dental pulp stem cells (hDPSCs) and forming a tooth-like structure with the mouse tooth mesenchyme. Overall, our differentiation protocol provides a practical approach for applying hiPSCs for tooth regeneration.

Skeletal remains are among the most challenging forensic samples, and when extracting DNA from them, destructive grinding is usually employed to obtain a sufficient quantity of DNA. When identifying skeletonized remains, a nondestructive extraction method is of great importance, and undamaged skeletal remains should be returned to relatives after identification due to ethical issues. Teeth are a good source of DNA, which can be found in dental pulp, dentin, and cementum. Similar to bones, highly destructive grinding of the entire tooth is usually employed in the standard forensic extraction procedure. Recent studies have shown that DNA can be best preserved within teeth in the cementum layer of the tooth root. The DNA in the tooth root surface is easily accessible. A simple and fast nondestructive method without grinding, drilling, or scraping of the tooth was developed. A commercial forensic extraction kit was used for automated DNA purification. Sixty-two canines from adult skeletons excavated from two archaeological cemeteries dating from the 13th to 19th centuries were used for analysis. After chemical cleaning and UV irradiation, demineralization was performed by submerging the tooth in 0.5 M EDTA, followed by lysis of demineralized tissue and automated DNA purification. Real-time PCR quantification was employed to determine the quality and quantity of DNA. The efficiency of the nondestructive DNA extraction method developed for genetic analysis of teeth was evaluated by determining the DNA yield, degree of DNA degradation, and success of short tandem repeat (STR) typing. The results showed high efficiency of the method developed, with highly informative STR profiles obtained from 74 % of archaeological canines analyzed. This study highlights the potential of a nondestructive method for analysis of skeletal remains, and it discusses the practical implications of teeth for forensic investigations. The method developed to physically preserve the tooth is simple, fast, and highly efficient, and, because of reduced manual handling, it has a low risk of contamination. •Nondestructive DNA extraction method allows preservation of the specimen.•Canines from 62 adult skeletons from modern-era cemeteries were analyzed.•DNA was extracted employing decalcification and lysis without damaging the tooth.•Highly informative STR profiles were generated from 74 % of canines.