High-frequency low-intensity semiconductor laser irradiation enhances osteogenic differentiation of human cementoblast lineage cells.

PURPOSE: Laser irradiation activates a range of cellular processes in the periodontal components and promotes tissue repair. However, its effect on osteogenic differentiation of human cementoblast lineage cells remains unclear. This study aimed to examine the effects of high-frequency semiconductor laser irradiation on the osteogenic differentiation of human cementoblast lineage (HCEM) cells. METHODS: HCEM cells were cultured to reach 80% confluence and irradiated with a gallium-aluminum-arsenide (Ga-Al-As) semiconductor laser with a pulse width of 200 ns and wavelength of 910 at a dose of 0-2.0 J/cm2. The outcomes were assessed by analyzing the mRNA levels of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), and type I collagen (COLL1) using real-time polymerase chain reaction (PCR) analysis 24 h after laser irradiation. Cell mineralization was evaluated using ALP activity, calcium deposition, and Alizarin Red staining. RESULTS: The laser-irradiated HCEM cells showed significantly enhanced gene expression levels of ALP, RUNX2, and COLL1 as well as ALP activity and calcium concentration in the culture medium compared with the non-irradiated cells. In addition, enhanced calcification deposits were confirmed in the laser-irradiated group compared with the non-irradiated group at 21 and 28 days after the induction of osteogenic differentiation. CONCLUSION: High-frequency semiconductor laser irradiation enhances the osteogenic differentiation potential of cultured HCEM cells, underscoring its potential utility for periodontal tissue regeneration.

Population differences in dental cementum growth rates: Implications for using cementum thickness as a method for age estimation.

OBJECTIVES: Age at death estimation is a key element to many research questions in biological anthropology, archeology, and forensic science. Dental cementum is a tissue of choice for the estimation of age at death in adult individuals as it continues deposition for the entirety of an individual's life. Previous works have devised regression formulas correlating cementum thickness to age at death. However, interpopulation variances are unknown, and it is therefore not clear whether regressions based on a single population are applicable to individuals with different ancestries. MATERIALS AND METHODS: Here, we use a sample (n = 52) of teeth from individuals with known age at tooth extraction/death of European, African, and East Asian ancestry to assess whether there are interpopulations differences in cementum growth rate. We measured growth rate in four different areas (2nd and 5th decile of both the lingual and buccal aspect of the root) of each tooth and used nonparametric tests to evaluate population differences in growth rate between homologous regions of the teeth. RESULTS: The results of the analyses show that, even after controlling for tooth size, individuals of European ancestry have significantly lower growth rates than those of both African and East Asian ancestry across all four tooth areas. DISCUSSION: These results call into question the applicability of the regression formulas derived from European ancestry individuals to individuals of other ancestries.

The activin/BMP-2 chimera AB204 promotes periodontal tissue regeneration in a buccal dehiscence model: a pilot study.

PURPOSE: A combination of activin and bone morphogenetic protein-2 (BMP-2), termed AB204, has been shown to improve osteogenic potential with fewer side effects than BMP-2 alone. This study was performed to evaluate the effect of AB204 on periodontal tissue regeneration in a dog buccal dehiscence model. METHODS: Buccal dehiscence defects were created on the maxillary premolars (P1, P2, and P3) of 6 mongrel dogs. After 5 weeks, the dogs were randomly assigned to 1 of 3 groups: the control, collagen matrix (CM), and CM/AB204 groups. Grafting procedures were then performed. The dogs were sacrificed 8 weeks after the grafting procedure, and volumetric and histological analyses were conducted. RESULTS: The thickness of the buccal gingiva in the CM/AB204 group was greater than those in the other groups at 2 weeks (P<0.05). The ridge width in the AB204/CM group exceeded the width in the other groups at 4 and 8 weeks; however, the difference was not statistically significant. Histological analysis revealed that the CM/AB204 group demonstrated the formation of new bone surrounded by newly formed periodontal ligament and cementum (P=0.035). CONCLUSIONS: The combined application of CM and AB204 shows promise in facilitating the regeneration of periodontal attachment, including the formation of new bone, cementum, and periodontal ligament.

Glycometabolic reprogramming in cementoblasts: A vital target for enhancing cell mineralization.

Cementum, a constituent part of periodontal tissues, has important adaptive and reparative functions. It serves to attach the tooth to alveolar bone and acts as a barrier delimit epithelial growth and bacteria evasion. A dynamic and highly responsive cementum is essential for maintaining occlusal relationships and the integrity of the root surface. It is a thin layer of mineralized tissue mainly produced by cementoblasts. Cementoblasts are osteoblast-like cells essential for the restoration of periodontal tissues. In recent years, glucose metabolism has been found to be critical in bone remodeling and osteoblast differentiation. However, the glucose metabolism of cementoblasts remains incompletely understood. First, immunohistochemistry staining and in vivo tracing with 18 F-fluorodeoxyglucose (18 F-FDG) revealed significantly higher glucose metabolism in cementum formation. To test the bioenergetic pathways of cementoblast differentiation, we compared the bioenergetic profiles of mineralized and unmineralized cementoblasts. As a result, we observed a significant increase in the consumption of glucose and production of lactate, coupled with the higher expression of glycolysis-related genes. However, the expression of oxidative phosphorylation-related genes was downregulated. The verified results were consistent with the RNA sequencing results. Likewise, targeted energy metabolomics shows that the levels of glycolytic metabolites were significantly higher in the mineralized cementoblasts. Seahorse assays identified an increase in glycolytic flux and reduced oxygen consumption during cementoblast mineralization. Apart from that, we also found that lactate dehydrogenase A (LDHA), a key glycolysis enzyme, positively regulates the mineralization of cementoblasts. In summary, cementoblasts mainly utilized glycolysis rather than oxidative phosphorylation during the mineralization process.

Force-Loaded Cementocytes Regulate Osteoclastogenesis via S1P/S1PR1/Rac1 Axis.

Orthodontically induced inflammatory root resorption (OIIRR) is the major iatrogenic complication of orthodontic treatment, seriously endangering tooth longevity and impairing masticatory function. Osteoclasts are thought to be the primary effector cells that initiate the pathological process of OIIRR; however, the cellular and molecular mechanisms responsible for OIIRR remain unclear. Our previous studies revealed that cementocytes, the major mechanically responsive cells in cementum, respond to compressive stress to activate and influence osteoclasts locally. For this study, we hypothesized that the sphingosine-1-phosphate (S1P) signaling pathway, a key mechanotransduction pathway in cementocytes, may regulate osteoclasts under the different magnitudes of either physiologic compressive stress that causes tooth movement or pathologic stress that causes OIIRR. Here, we show a biphasic effect of higher compression force stimulating the synthesis and secretion of S1P, whereas lower compression force reduced signaling in IDG-CM6 cementocytes. Using conditioned media from force-loaded cementocytes, we verified the cell-to-cell communication between cementocytes and osteoclasts and show that selective knockdown of S1PR1 and Rac1 plays a role in cementocyte-driven osteoclastogenesis via the S1P/S1PR1/Rac1 axis. Most importantly, the use of inhibitors of this axis reduced or prevented the pathological process of OIIRR. The intercellular communication mechanisms between cementocytes and osteoclasts may serve as a promising therapeutic target for OIIRR.

Limitaciones Técnicas del Método de Conteo de Anulaciones del Cemento para Estimación de Edad. Hallazgos a Partir de Una Revisión con Búsqueda Sistemática / Technical Limitations of Cementum Annulation Count Method for age Estimation. Findings From A Scoping Review

En la última década, la odontología forense se ha enfocado en el desarrollo de metodologías para la estimación de edad (EE) debido a la gran demanda en procesos identificatorios. Entre esas técnicas, el conteo de anulaciones del cemento dental (TCA) ha ofrecido resultados promisorios, pero también contradictorios que han generado dudas sobre su precisión y confiabilidad. El objetivo de este trabajo fue caracterizar, establecer alcances, e identificar las limitaciones del conteo de TCA según los actuales estándares normativos y metodológicos. Se realizó una revisión con búsqueda sistemática del método de conteo de TCA para EE incluyendo estudios experimentales y notas técnicas en las bases PubMed/Medline, Scopus, Web of Science (WoS) y Embase. Se emplearon los términos "estimation", "age" y "cementum", con búsqueda manual complementaria en Google Scholar. Se excluyeron revisiones, estudios en colecciones arqueológicas, estudios radiológicos y cartas al editor. La búsqueda arrojó un total de 273 artículos, seleccionándose 27 que cumplieron con los criterios de inclusión. La mayoría de los estudios fueron publicados en Asia, particularmente en India (n=21). Sólo 6 artículos declararon el número total de individuos, tipos de diente y de cortes histológicos, siendo el premolar el más estudiado. Apenas dos artículos evaluaron la calidad de la muestra a analizar mediante legibilidad de los cortes obtenidos. El test más empleado para evaluar la precisión del método fue el coeficiente de correlación de Pearson (n=21). Estos hallazgos exponen la alta heterogeneidad reportada en las metodologías de EE mediante conteo por TCA, por lo que aún no existe un proceso estandarizado que abarque todas sus etapas y entregue resultados confiables siguiendo los estándares jurídicos actuales para la evidencia científica. Un mayor control de las limitaciones técnicas detectadas aumentará el valor como prueba en un contexto identificatorio legal o forense.

SUMMARY: In the last decade, forensic odontology has focused on the development of age estimation (AE) methodologies due to the great request in identification processes. Among these techniques, the tooth cementum annulation (TCA) count method has offered promising but also contradictory results, raising questions about its accuracy and reliability. The aim of this work was to characterize, establish the scope, and identify the limitations of the TCA count method according to the current normative and methodological standards. A scoping review was carried out for TCA count methods for AE, including experimental studies and technical notes in the PubMed/Medline, Scopus, Web of Science (WoS) and Embase databases. The terms "estimation", "age" and "cementum" were used, with a complementary manual search in Google Scholar. Reviews, studies in archaeological collections, radiological studies and letters to the editor were excluded. The search yielded a total of 273 articles, selecting 27 of them that met the inclusion criteria. Most of the studies were published in Asia, particularly India (n=21). Only 6 articles declared the total number of individuals, types of teeth, and histological sections, with the premolar being the most studied. Only two articles evaluated the quality of the sample to be analyzed through the legibility of the cuts obtained. The most widely used test to assess the precision of the method was the Pearson correlation coefficient (n=21). These findings expose the high heterogeneity reported in EE methodologies by counting TCA, so there is still no standardized process that covers in all its stages and delivers reliable results following current legal standards for scientific evidence. More control of the detected technical limitations will increase the value as evidence in a legal or forensic identification context.

Life history in primate teeth is revealed by changes in major and minor element concentrations measured via field-emission SEM-EDS analysis.

Overcoming the non-specificity of histological accentuated growth lines in hard tissues is an ongoing challenge. Identifying season at death and reproductive events has profound implications for evolutionary, ecological and conservation studies. Dental cementum is a mineralized tissue with yearly periodicity that continues deposition from tooth formation until death, maintaining a record spanning almost the entire life of an individual. Recent work has successfully employed elemental analysis of calcified incremental tissues to detect changes in extrinsic conditions such as diet and climate and to identify two important life-history milestones: weaning and sexual maturity. Here, we employ field-emission scanning electron microscopy and energy-dispersive X-ray analysis to measure the relative concentrations of calcium, phosphorous, oxygen, magnesium and sodium in the cementum of 34 teeth from seven male and female rhesus macaques with known medical and life-history information. We find that changes in relative magnesium concentrations correspond with reproductive events in females and breastfeeding in infants. Additionally, we observe seasonal calcium patterns in 77.3% of the samples.

Insights into the aetiologies of hypercementosis: A systematic review and a scoring system.

OBJECTIVES: This paper aims to better define hypercementosis, investigate its described potential aetiologies, and determine whether there are different patterns of cementum apposition and if they are a function of their supposed aetiology. DESIGN: A literature review was undertaken using the Medline, DOSS, Scopus and Cochrane Library electronic databases. Two co-authors selected the published works independently, extracted the data in accordance with the PRISMA statement. RESULTS: Among 546 articles, 75 articles were finally selected. Eight different supposed aetiologies were identified: (1) intensive masticatory effort, (2) systemic disease, (3) carious lesion and apical periodontitis, (4) impaction, (5) periodontal disease, (6) concrescence, (7) super-eruption, and (8) drugs. Some of these aetiologies can be combined in the same tooth. Hypercementosis manifestations are various in nature and extent with different patterns that may be aetiology-specific. To improve the description and associated consistency in the characterisation of hypercementosis, in this review but also in future studies, we propose a new qualitative scoring system to quickly characterise hypercementosis and determine its most relevant aetiology. CONCLUSIONS: This systematic review demonstrates that hypercementosis is a complex and not yet well-defined condition. Some forms of apposition are specific to a given aetiology. The hypercementosis characterisation may contribute to document the oral condition and/or the individuals masticatory activity.

M2 macrophages with inflammation tropism facilitate cementoblast mineralization.

BACKGROUND: Cementum regeneration was regarded as the critical goal for periodontal regeneration, and M2 macrophage-based therapy was expected to be a promising strategy. However, little is known about the effects of M2 macrophages on cementoblast mineralization and tropism, especially under inflammation. Here we investigated for the first time the crosstalk between M2 macrophages and Porphyromonas gingivalis (Pg)-stimulated cementoblasts. METHODS: M2 macrophages were induced with interleukin (IL)-4, and identified. CC-chemokine ligand 2 (CCL2) expression and secretion of inflammatory cementoblasts were detected by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), western blotting (WB), immunohistochemistry for apical periodontitis (AP) mice, and by enzyme-linked immunosorbent assay. Crystal violet staining was used to observe macrophage migration. Conditional medium (CM) and transwell coculture methods were applied to evaluate the effects of M2 macrophages on cementum mineralization with or without Pg, and to explore the mechanism. Mineralization-related markers and pathway-related proteins were measured by RT-qPCR and WB. RESULTS: M2 macrophages were identified successfully. We found an increase of CCL2 in cementoblasts and their supernatant. Also, higher CCL2 in cementoblasts was observed in the AP model. Superior recruitment of M2 macrophages to supernatant from Pg-stimulated cementoblasts or CCL2-containing medium was verified. Moreover, CM2 and Trans-M2 showed better mineralization-accelerating and rescuing effects when compared to their controls, and application of p38 inhibitor partially blocked the promotion. CONCLUSIONS: Our study demonstrated the inflammation-targeting and mineralization-promoting effects of M2 macrophages on cementoblasts, which may provide evidence for M2 macrophage-based cementum regeneration.

Glycogen synthase kinase 3 inhibition enhances mineral nodule formation by cementoblasts in vitro

Abstract This study aimed to investigate whether GSK-3 inhibition (CHIR99021) effectively promoted mineralization by cementoblasts (OCCM-30). OCCM-30 cells were used and treated with different concentrations of CHIR99021 (2.5, 5, and 10 mM). Experiments included proliferation and viability, cellular metabolic activity, gene expression, and mineral nodule formation by Xylene Orange at the experimental time points. In general, CHIR99021 did not significantly affect OCCM-30 viability and cell metabolism (MTT assay) (p > 0.05), but increased OCCM-30 proliferation at 2.5 mM on days 2 and 4 (p < 0.05). Data analysis further showed that inhibition of GSK-3 resulted in increased transcript levels of Axin2 in OCCM-30 cells starting as early as 4 h, and regulated the expression of key bone markers including alkaline phosphatase (Alp), runt-related transcription factor 2 (Runx-2), osteocalcin (Ocn), and osterix (Osx). In addition, CHIR99021 led to an enhanced mineral nodule formation in vitro under both osteogenic and non-osteogenic conditions as early as 5 days after treatment. Altogether, the results of the current study suggest that inhibition of GSK-3 has the potential to promote cementoblast differentiation leading to increased mineral deposition in vitro.

Effect of local administration of injectable platelet-rich fibrin on root resorption during orthodontic tooth movement in dogs.

Background: This study aimed to assess the effect of local administration of injectable platelet-rich fibrin (i-PRF) on root resorption during orthodontic tooth movement in dogs. Materials and Methods: This animal study was conducted on 4 adult male mongrel dogs. The right and left maxillary first premolars of the dogs were extracted, and a Nickel-Titanium closed coil spring was used to connect the canine to the second premolar with 150 g load. Next, 0.5 cc of i-PRF was injected in one quadrant of the maxilla around the second premolar into the periodontal ligament. The other quadrant of the maxilla served as the control group and received saline injection. Injections were performed at 1, 21, and 42 days, and the dogs were sacrificed after 63 days. Histological sections were prepared and cementum resorption, secondary cementum formation, and number of cementoblasts and cementoclasts were compared between the two groups by the Friedman test, Wilcoxon test, and Mann-Whitney test (α = 0.05). Results: The mean percentage of cementum resorption (17.75% ± 5.56%) and secondary cementum formation (14.50% ± 6.65%), and the mean number of cementoblasts (10.25 ± 2.36) and cementoclasts (9.75 ± 4.71) were insignificantly higher in the i-PRF group than the corresponding values (13.75% ± 4.34%, 8.50% ± 2.88%, 7.75 ± 1.25, and 6.50 ± 3.10, respectively) in the control group (P > 0.05). Conclusion: Administration of i-PRF insignificantly increased the percentage of cementum resorption, secondary cementum formation, number of cementoblasts, and number of cementoclasts.

Dental age estimation by cementum incremental lines counting: A systematic review and meta-analysis.

The estimation of dental age by cementum incremental lines (CIL) is a widely investigated method; however, its reliability remains uncertain. The aim of this article was to assess whether CIL are a reliable biological indicator for estimating dental age. A search was performed in Embase, LILACS, PubMed/MEDLINE, SciELO, Scopus and Web of Science databases using a combination of terms related to the topic. Two independent reviewers used inclusion and exclusion criteria so that relevant articles were selected and evaluated. For the risk of bias analysis, a checklist from The Joanna Briggs Institute was applied. For the meta-analysis, Pearson's Correlation Coefficient between chronological age and estimated age was considered as an effect measure. The heterogeneity of studies was assessed using the Cochran's Q statistical test (p < 0.05), and the publication bias using the asymmetry of the Funnel plot and Egger's linear regression test (p < 0.05). Most selected articles had low risk of bias. Although not all studies were included in the meta-analysis, it demonstrated the presence of high heterogeneity among them. Despite this, the synthesized result indicated that the age estimated by CIL count has a high correlation with chronological age. Furthermore, the graphical analysis suggested the absence of publication bias, which was confirmed by the Egger's linear regression test. Therefore, there is scientific evidence that CIL are reliable in estimating dental age, but the method requires a standardized protocol to be followed, as well as the rigorous choice of the root area to be analyzed.

PGC-1 alpha regulates mitochondrial biogenesis to ameliorate hypoxia-inhibited cementoblast mineralization.

Hypoxia often occurs in inflammatory tissues, such as tissues affected by periodontitis and apical periodontitis lesions. Mitochondrial biogenesis can be disrupted in hypoxia. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a core factor required for mitochondrial biogenesis. Cementoblasts are root surface lining cells that play an integral role in cementum formation. There is a dearth of research on the effect of hypoxia on cementoblasts and underlying mechanisms, particularly in relation to mitochondrial biogenesis during the hypoxic process. In this study, we found that the expression of hypoxia inducible factor-1α was elevated in apical periodontitis tissues in vivo. In contrast, periapical lesions exhibited a reduction of PGC-1α expression. For in vitro experiments, cobalt chloride (CoCl2 ) was used to induce hypoxia. We observed that CoCl2 -induced hypoxia suppressed the mineralization ability and mitochondrial biogenesis of cementoblasts, accompanied by abnormal mitochondria morphology. Furthermore, we found that CoCl2 blocked the p38 pathway, while it activated the Erk1/2 pathway, with the former upregulating the expression of PGC-1α, while the latter reversed the effects. Overall, our findings demonstrate that mitochondrial biogenesis, especially via PGC-1α, is impaired during cementogenesis in the context of CoCl2 -induced hypoxia, dependent on the mitogen-activated protein kinase signaling pathway.

Canonical Wnt/ß-catenin signaling has positive effects on osteogenesis, but can have negative effects on cementogenesis.

BACKGROUND: To date, therapeutic approaches for cementum regeneration are limited and outcomes remain unpredictable. A significant barrier to improve therapies for cementum regeneration is that the cementocyte and its intracellular signal transduction mechanisms remain poorly understood. This study aims to elucidate the regulatory mechanism of Wnt pathway in cementogenesis. METHODS: The effects of canonical Wnt signaling were compared in vitro using immortalized murine cementocyte cell line IDG-CM6 and osteocyte cell line IDG-SW3 by quantitative real-time polymerase chain reaction, Western blot, confocal microscopy, alkaline phosphatase (ALP) assay, and Alizarin red S staining. In vivo, histological changes of cementum and bone formation were examined in transgenic mice in which constitutive activation of ß-catenin is driven by Dmp1 promoter. RESULTS: Expression of components of the Wnt/ß-catenin pathway were much greater in the IDG-SW3 cells compared with the IDG-CM6 cells resulting in much lower expression of Sost/sclerostin in the IDG-SW3 cells. In the IDG-CM6 cells, low dose Wnt3a (20 ng/ml) had a modest effect while high dose (200 ng/ml) inhibited runt-related transcription factor 2, osterix, ALP, and osteopontin in contrast to the IDG-SW3 cells where high dose Wnt3a dramatically increased mRNA expression of these same markers. However, high Wnt3a significantly increased mRNA for components of Wnt/ß-catenin signaling pathway in both IDG-CM6 and IDG-SW3 cells. In vivo, constitutive activation of ß-catenin in the Dmp1-lineage cells in mice leads to bone hyperplasia and cementum hypoplasia. CONCLUSION: These findings indicate that Wnt signaling has distinct and different effects on the regulation of long bone as compared with cementum.

The Bone Sialoprotein RGD Domain Modulates and Maintains Periodontal Development.

Bone sialoprotein (gene: Ibsp; protein: BSP) is a multifunctional extracellular matrix protein present in bone, cementum, and dentin. Accumulating evidence supports BSP as a key regulator of mineralized tissue formation via evolutionarily conserved functional domains, including a C-terminal integrin-binding Arg-Gly-Asp (RGD) domain implicated in extracellular matrix-cell signaling. Ablation of Ibsp in mice (Ibsp-/-) results in impaired bone growth and mineralization and defective osteoclastogenesis, with effects in the craniofacial region including reduced acellular cementum formation, detachment of the periodontal ligament (PDL), alveolar bone hypomineralization, and severe periodontal breakdown. We hypothesized that BSP-RGD plays an important role in cementum and alveolar bone formation and mineralization, as well as periodontal function. This hypothesis was tested by replacing the RGD motif with a nonfunctional Lys-Ala-Glu (KAE) sequence in (IbspKAE/KAE) mice and OCCM.30 murine (IbspKAE) cementoblasts. The RGD domain was not critical for acellular or cellular cementum formation in IbspKAE/KAE mice. However, PDL volume and thickness were increased, and significantly more tartrate-resistant acid phosphatase-positive osteoclasts were found on alveolar bone surfaces of IbspKAE/KAE mice versus wild type mice. PDL organization was disrupted as indicated by picrosirius red stain, second harmonic generation imaging, dynamic mechanical analysis, and decreased asporin proteoglycan localization. In vitro studies implicated RGD functions in cell migration, adhesion, and mineralization, and this was confirmed by an ossicle implant model where cells lacking BSP-RGD showed substantial defects as compared with controls. In total, the BSP-RGD domain is implicated in periodontal development, though the scale and scope of changes indicated by in vitro studies indicate that other factors may partially compensate for and reduce the phenotypic severity of mice lacking BSP-RGD in vivo.

Dental cementum virtual histology of Neanderthal teeth from Krapina (Croatia, 130-120 kyr): an informed estimate of age, sex and adult stressors.

The evolution of modern human reproductive scheduling is an aspect of our life history that remains vastly uncomprehended. The present work aims to address this gap by validating a non-destructive cutting-edge methodology to infer adult life-history events on modern teeth with known life history and then applying it to fossil specimens. We use phase-contrast synchrotron X-ray microtomography to visualize the dental cementum of 21 specimens: nine contemporary humans; 10 Neanderthals from Krapina (Croatia, 130-120 kyr); one Neolithic Homo sapiens from Ajmana (Serbia); and one Mesolithic H. sapiens from Vlasac (Serbia). We were able to correctly detect and time (root mean square error = 2.1 years; R2 = 0.98) all reproductive (menarche, parturition, menopause) and other physiologically impactful events in the modern sample. Nonetheless, we could not distinguish between the causes of the events detected. For the fossil specimens, we estimated age at death and age at occurrence of biologically significant events. Finally, we performed an exploratory analysis regarding possible sexual dimorphism in dental cementum microstructure, which allowed us to correctly infer the sex of the Neolithic specimen, for which the true value was known via DNA analysis.

Effects of baicalin on the proliferation and expression of OPG and RANKL in human cementoblast-lineage cells.

BACKGROUND/PURPOSE: Baicalin, a natural bioactive flavonoid extracted from Scutellaria baicalensis Georgi, mediates bone metabolism, and recent studies have revealed that it has cell signaling properties. However, its biological functions in cementoblasts still remain unclear. This study therefore aimed to investigate the effects of baicalin on bone resorption markers, including osteoprotegerin (OPG) and receptor activator of nuclear factor-κß ligand (RANKL), in human cementoblast-lineage cells, as well as their proliferation ability. MATERIALS AND METHODS: Human cementoblast cell line (HCEM) cells were cultured and treated with 0, 0.01, 0.1, or 1 µM of baicalin. The proliferative capacity of cultured HCEM cells was analyzed using bromodeoxyuridine immunoassay and cell counting. The baicalin effect on OPG and RANKL expression was determined using quantitative polymerase chain reaction (qPCR) and western blotting. Furthermore, OPG expression was measured in 1 µM baicalin-treated HCEM cells in the presence or absence of the Wnt signaling pathway inhibitor, Dickkopf (Dkk)-1, using qPCR and western blotting. RESULTS: The addition of 0.01, 0.1, and 1 µM of baicalin did not significantly change the proliferative capacity of cultured HCEM cells. Compared with the non-supplemented group, baicalin increased and suppressed OPG and RANKL gene and protein expression, respectively, in a concentration-dependent manner. OPG mRNA and protein expression levels were increased by 1 µM baicalin, which was suppressed by Dkk-1 addition. CONCLUSION: Baicalin enhanced OPG expression in HCEM cells through the Wnt/beta-catenin signaling pathway, which could contribute to periodontal tissue regeneration.

Dental cementum examination with SEM/EDX for unraveling details along the lifeline to assist identification of a female individual.

In this work, we present a novel approach of forensic examination of the dental cementum by Scanning Electron Microscopy (SEM) as an imaging tool, complemented by semiquantitative elemental analysis of the incremental lines with an Energy Dispersion X-ray analyzer. Tooth samples were collected from female donors who are known to have given single or multiple childbirths. This research is aimed to prove the following hypothesis - if pregnancy (possibly followed by breastfeeding) affects the calcium and phosphorus levels in female metabolism, then increased levels of Ca and P should be detected in the dental cementum region corresponding to the age of the pregnancy. For this purpose, EDX spectra were taken from sampling points, evenly aligned along the direction of the cementum growth. The most intensive X-ray peaks were analyzed employing qualitative and semiquantitative elemental analysis. Results showed that the changes in the peak values of Ca and P levels in the cementum along the lifeline could be related to the biological age of pregnancy, possibly followed by breastfeeding. The observed variations in other elements could also suggest some other physiological conditions or nutrition patterns. These preliminary results could trigger more profound and extensive research involving more sophisticated techniques for elemental analysis, such as PIXE (Proton Induced X-ray Emission). Correlation of the element levels to certain conditions may bring a new paradigm of the unique forensic value of the dental cementum, on which the life story of a person is literally "written in a stone". This method could serve pure forensic purposes and archeological examinations of human findings in support of historical facts.

Automated age-at-death estimation by cementochronology: Essential application or additional complication?

It has been repeatedly acknowledged that age-at-death estimation based on dental cementum represents a partial and time-consuming method that hinders adoption of this histological approach. User-friendly micrograph analysis represents a growing request of cementochronology. This article evaluates the feasibility of using a module to accurately quantify cementum deposits and compares the module's performance to that of a human expert. On a dental collection (n = 200) of known-age individuals, precision and accuracy of estimates performed by a developed program (101 count/tooth; n = 20,200 counts) were compared to counts performed manually (5 counts/tooth; n = 975 counts). Reliability of the software and agreement between the two approaches were assessed by intraclass correlation coefficient and Bland Altman analysis. The automated module produced reliable and reproducible counts with a higher global precision than the human expert. Although the software is slightly more precise, it shows higher sensitivity to taphonomic damages and does not avoid the trajectory effect described for age-at-death estimation in adults. Likewise, for human counts, global accuracy is acceptable, but underestimations increase with age. The quantification of the agreement between the two approaches shows a minor bias, and 94% of individuals fall within the intervals of agreement. Automation gives an impression of objectivity even though the region of interest, profile position and parameters are defined manually. The automated system may represent a time-saving module that can allow an increase in sample size, which is particularly stimulating for population-based studies.