Cementum Research Articles

Petrous bones versus tooth cementum for genetic analysis of aged skeletal remains.

A proper sampling strategy is important to obtain sufficient DNA for successful identification of aged skeletal remains. The petrous bone is the highest DNA-yielding bone in the human body. Because DNA extraction from the petrous bone is very destructive, the demand for other DNA sources is significant. When investigating aged skeletal remains, teeth are usually preserved, and recent studies have shown that DNA in teeth can be best preserved in the dental cementum that surrounds the surface of the tooth root. To extract DNA from the surface of the tooth root, a nondestructive method without grinding was used. Petrous bones and teeth from 60 archaeological adult skeletons were analyzed. The DNA yield, degree of DNA degradation, and STR typing success were compared, and the results showed higher DNA yield and higher amplification success in petrous bones, despite higher degradation of petrous bones' DNA. The greater success of petrous bones is associated with poorly preserved DNA in a quarter of the teeth analyzed. When teeth with badly preserved DNA were excluded from the statistical analysis, no differences in the success of STR loci amplification were observed even if DNA yield was higher in petrous bones, which can be explained by greater degradation of petrous bones' DNA. When teeth are well preserved, they can be used for genetically analyzing aged skeletal remains instead of petrous bones, and a rapid nondestructive extraction method can be applied to shorten the identification process and to physically preserve the biological specimen.

Forensic significance of dental cementum

Forensic significance of dental cementum

The origins of mammal growth patterns during the Jurassic mammalian radiation.

We use synchrotron x-ray tomography of annual growth increments in the dental cementum of mammaliaforms (stem and crown fossil mammals) from three faunas across the Jurassic to map the origin of patterns of mammalian growth patterns, which are intrinsically related to mammalian endothermy. Although all fossils studied exhibited slower growth rates, longer life spans, and delayed sexual maturity relative to comparably sized extant mammals, the earliest crown mammals developed significantly faster growth rates in early life that reduced at sexual maturity, compared to stem mammaliaforms. Estimation of basal metabolic rates (BMRs) suggests that some fossil crown mammals had BMRs approaching the lowest rates of extant mammals. We suggest that mammalian growth patterns first evolved during their mid-Jurassic adaptive radiation, although growth remained slower than in extant mammals.

The off-season of dental cementum investigations. A critical appraisal of season-of-death prediction in medico-legal investigations

The off-season of dental cementum investigations. A critical appraisal of season-of-death prediction in medico-legal investigations

Reindeer prey mobility and seasonal hunting strategies in the late Gravettian mammoth steppe

Reindeer are part of the faunal suite that dominated central Europe during the last glacial cycle. Their importance to Late Gravettian hunters as prey and a source of raw materials (hide, bone, antler) is well attested, however the context of Late Gravettian reindeer predation is lesser understood. This paper presents an investigation of human and reindeer predator-prey interactions at the Late Gravettian kill-butchery site of Lubná VI, Czech Republic. We reconstruct seasonal mobility (87Sr/86Sr, δ18O), diet (δ13C, δ15N) and season of death (dental cementum) of up to nine reindeer prey, to inform on the strategic choices made by Late Gravettian hunters. Results indicate that most hunted reindeer lived year-round in the foothills of the Bohemian-Moravian highlands near where Lubná is located, at altitudes between ~ 200–450 m above present sea level, while a smaller number showed evidence of seasonal migration between this area and the open plains of the Elbe river corridor (Bohemian Cretaceous basin). No evidence for long distance migration of reindeer was detected, indicating that productive local environments were supporting reindeer herds within a single annual territory. Meanwhile, areas higher than ~ 450 m above present sea level were avoided entirely by all analysed individuals, consistent with these areas being topographic barriers to movement due to climate severity. We conclude that hunters visited Lubná as part of a logistically-organised subsistence strategy, deliberately targeting reindeer in late autumn when fat supplies, hides and antler are in prime condition knowing that they would reliably encounter their prey at this location.

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

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. 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. 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. These results call into question the applicability of the regression formulas derived from European ancestry individuals to individuals of other ancestries.

Use of Nanoparticles in Regenerative Dentistry: A Systematic Review.

nanoparticles are tiny-sized materials whose characteristics and properties mean that their association with dental materials is being investigated to ascertain their effects and possible benefits on tooth structures. This systematic review aimed to qualitatively collect in vitro studies that address the potential application of different nanoparticles in dental regeneration. Following an exhaustive search and article selection process, 16 in vitro studies that met our eligibility criteria were included. BG-NPs were analyzed across five studies, with three demonstrating their impact on the growth and differentiation of human hDPSCs. CS-NPs were examined in three studies, with findings from two indicating a significant effect on the differentiation of SCAPs. Nanoparticles' therapeutic potential and their stimulatory effect on promoting the regeneration of cells of the dentin-pulp complex have been proven. Their effect is altered according to the type of nanoparticle, concentration, and substances associated with them and, depending on these variables, they will affect the pulp, dentine, and dental cementum differently.

Exosomes and exosome composite scaffolds in periodontal tissue engineering.

Promoting complete periodontal regeneration of damaged periodontal tissues, including dental cementum, periodontal ligament, and alveolar bone, is one of the challenges in the treatment of periodontitis. Therefore, it is urgent to explore new treatment strategies for periodontitis. Exosomes generated from stem cells are now a promising alternative to stem cell therapy, with therapeutic results comparable to those of their blast cells. It has great potential in regulating immune function, inflammation, microbiota, and tissue regeneration and has shown good effects in periodontal tissue regeneration. In addition, periodontal tissue engineering combines exosomes with biomaterial scaffolds to maximize the therapeutic advantages of exosomes. Therefore, this article reviews the progress, challenges, and prospects of exosome and exosome-loaded composite scaffolds in periodontal regeneration.

Dental cementum anchored microspheres embedded in a self-healing hydrogel for the antibacterial, anti-inflammation, osteogenic, and anti-osteoclastic management of periodontitis disease.

Periodontitis, a prevalent chronic oral disease, poses a significant threat to periodontal tissues, often resulting in substantial attachment loss and tooth shedding. Leveraging the principles of bone affinity and the mechanism underlying tetracycline pigmentation of teeth, this study strategically employed tetracycline (TC) as a bone-affinity group. We modified TC on the surface of polylactic-co-glycolic acid copolymer (PLGA) microspheres (MSs) through covalent binding, and then loaded berberine (BBR) MSs into a thermosensitive self-healing hydrogel delivery system (BBR/TC-MS). It was verified that the BBR/TC-MS gel rapidly formed an in situ reservoir in the periodontal pocket upon injection, and the chelation between TC and cementum in the periodontal pocket enhanced the anchoring effect of the TC-modified microspheres on cementum, preventing their loss through gingival crevicular fluid. Subsequently, we proved in vitro and in vivo that the BBR/TC-MS gel has excellent bacteriostatic effects against the periodontal pathogenic bacteria Fusobacterium necrophorum (Fn), anti-inflammation property in periodontal and gingival tissues, and osteogenic effect by regulating the RANKL-RANK-OPG pathway to diminish osteoclast activity, thus continuously exerting antibacterial, anti-inflammatory, osteogenic, and anti-osteoclastic effects. This innovative approach holds promise as a targeted and effective strategy for combating multifaceted challenges posed by periodontitis.

A comparative evaluation of microleakage in three different luting agents used for posterior full metal crown: An in vitro study

The purpose of the study was to evaluate and compare the microleakage at the margins of nickel – chromium full metal crowns cemented with Zinc Phosphate cement, glass ionomer cement. And resin cement.: thirty freshly extracted human molars were selected for the study. Standardized tooth preparation is done with the help of customized metal zig attached to dental surveyor. On prepared teeth castings were fabricated and devided into three groups for the three luting agents namely zinc phosphate cement – Harvard, Glass ionomer cement – Ketac Cem and Resin cement – Rely X U200, each containing 10 samples. After cementation the cemented specimens were stored in artificial saliva for 24 hours. The teeth were then thermocycled between 5°C and 50°C and then treated with 50% silver nitrate stain for 60 minutes. Samples were placed under 150 watt flood lamp for 5 minutes to allow proper fixation of unfixed stain. Then they were embedded in clear acrylic resin and sectioned twice longitudinally. The sections were observed under the stereomicroscope and stain penetration were recorded at tooth cement interfaces. The readings were tabulated and analyzed statistically using Mann-Whitney U test and Kruskal-Wallis H test. .Zinc phosphate cement showed significantly maximum microleakage as compared to glass ionomer cement and resin cement. Resin cement showed significantly less microleakage as compared to glass ionomer cement and zinc phosphate cement. Glass ionomer cement showed more microleakage as compared to resin cement but less as compared to zinc phosphate cement

Dental Cementum in Anthropology

Dental Cementum in Anthropology

Differential effects of resolvin D1 and resolvin E1 on cementoblast function.

Resolvins are endogenous mediators of the resolution of inflammation. They are derived from omega-3 polyunsaturated fatty acid precursors. Resolvin D1 (RvD1) and Resolvin E1 (RvE1) are the best-characterized members for actively promoting periodontal regeneration in experimental animal models. Here, we evaluated the efficacy of RvD1 and RvE1 on cementoblasts, the key cells involved in dental cementum regeneration and the attachment of the tooth to the alveolar bone. Immortalized mouse cementoblasts (OCCM-30) were treated with different concentrations (0.1-1000ng/mL) of RvD1 and RvE1. Cell proliferation was measured using an electrical impedance-based real-time cell analyzer. Mineralization was evaluated with von Kossa staining. The mRNA expression of mineralized tissue-associated markers of bone sialoprotein (BSP), Type I collagen (COL I), osteocalcin (OCN), osteopontin (OPN), runt-related transcription factor 2 (RunX2), alkaline phosphatase (ALP), osteoprotegerin (OPG), receptor activator of nuclear factor kappa B (NF-κB) (RANK), receptor activator of NF-κB ligand (RANKL), and extracellular matrix-degrading enzymes [matrix metalloproteinase (MMP)-1, MMP-2, MMP-3, MMP-9, and their tissue inhibitors (TIMP-1, TIMP-2)], RvE1 receptor (ChemR23) and RvD1 receptor (ALX/PFR2), cytokines (tumor necrosis factor-alpha {TNF-α}, interleukin {IL}-1β, IL-6, IL-8, IL-10, IL-17), oxidative stress enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPX), and cyclooxygenase-2 (Cox-2)] were analyzed using quantitative polymerase chain reaction (qPCR). Both RvD1 and RvE1 (10-100ng/mL) significantly increased the proliferation of cementoblasts and mineralized nodules at all concentrations (p<0.05). RvE1 increased BSP, RunX2, and ALP compared with the RvD1 dose and time-dependently, while RvD1 and RvE1 differentially regulated COL-I. RvE1 increased OPG mRNA expression, whereas RANK-RANKL mRNA expression decreased by RvE1. MMP-2, MMP-3, MMP-9, TIMP-1, and TIMP-2 expressions were reduced by RvE1 compared with RvD1. Treatment of cementoblasts with RvD1 and RvE1 differentially affected cytokine and oxidative stress enzymes while significantly increasing their receptor expressions (ChemR23 and ALX/PFR2). RvD1 and RvE1 regulate proliferation, mineralization, and gene expression in cementoblasts using similar pathways while differentially affecting tissue degradation, suggesting a targeted therapeutic approach for cementum turnover during periodontal regeneration.

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.

The Effects of Experimental Whole-Body Burning on Histological Age-at-Death Estimation from Human Cortical Bone and Dental Cementum.

Whole-body donations (n = 6) were placed in various experimental fire-death scenarios to understand the histological effects of thermal alteration on bones and teeth. Midshaft samples of the femur, 6th rib, and metatarsal were removed from each donor pre- and post-burning to examine histomorphometric differences and test established age-at-death estimation methods. Dental samples were taken post-burning to test the applicability of dental cementum analysis for age-at-death estimation. Significant differences in osteon area or Haversian canal area between some pre- and post-burn samples were found although no patterns related to temperature or element were observable. The femoral age estimates across pre- and post-burn samples were 91% accurate across all donors. The point age estimates from the ribs compared to known age were significantly different (t(10) = 6.88, p &lt; 0.001) with an average difference of -18.53 years. Dental age estimates of post-burn samples were not significantly different from the known donor age (t(3) = -0.74, p = 0.512) with an average difference of -3.96 years. Overall, the results of this study show that thermally altered remains can be used for histologic age-at-death analysis of cortical bone and dental cementum, within certain burning parameters.

Nanocomposite based drug delivery for periodontal disease

Periodontal disease is the term used to describe some pathological conditions characterized by degeneration and inflammation of gums, periodontal ligaments, alveolar bone, and dental cementum. Periodontal disease involves destruction of alveolar bone around the teeth leading to defects or rather loss of the tooth if left untreated. This condition is caused by a chronic, mixed infection of Gram-negative and Gram-positive bacteria. Chlorhexidine (CHX) gluconate is an antiseptic, antifungal and bactericidal agent. CHX inhibits plaque formation by binding to anionic salivary glycoproteins and bacteria. Nano Hydroxyapatite (nHAP) is calcium phosphate in morphology and composition like the human hard tissues. Delivery of medications directly into the periodontal pockets alters the inflammatory response and reduces the pathogenic microbiota, an aspect which has attracted great interes. Result: The CHX Nanocomposites were non-toxic to human cells and promoted cell adhesion, proliferation, and spreading. The CHX Nanocomposites were found to be satisfactory in all respects, and CHX encapsulated in nanocomposites may be attractive candidates for the treatment of periodontal disease.

Short histological kaleidoscope - recent findings in histology. Part I.

This article is a review of new advances in histology, concerning either classification or structure of different tissular elements (basement membrane, hemidesmosomes, urothelium, glandular epithelia, adipose tissue, astrocytes), and various organs' constituents (blood-brain barrier, human dental cementum, tubarial salivary glands, hepatic stellate cells, pineal gland, fibroblasts of renal interstitium, Leydig testicular cells, ovarian hilar cells), as well as novel biotechnological techniques (tissue engineering in angiogenesis), recently introduced.

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.

Tooth Cementum Annulation: A Literature Review

Tooth Cementum Annulation (or TCA) is a technique that relies on the analysis of the incremental growth of dental cementum for age and season at death estimation. It has been extensively adopted as a “black box technique”, despite numerous controversies. Its potential in forensics called for this review, which aims to provide the reader with an overarching critical synthesis of what has been done and what is known about the TCA from different perspectives. Results have been divided according to three different themes: human, animal and evolutionary studies, as well as biological studies. The summary and comparison of these show the complexity of this topic, its limits, and how the scientific community can collectively collaborate for improvements. Overall, it is clear that the potential of the TCA is significant in terms of age and season at death estimation and that (as long as its biology is still addressed and researched for) there should not be any reason to not consider this technique as valid as the other anthropological methods adopted for biological profiling.

Tooth Cementum Thickness as a Method of Age Estimation in the Forensic Context

Simple SummaryIn a forensic context, it may be necessary to estimate the age at death of an individual from his or her skeletal remains. The age at death constitutes an essential identification parameter, along with sex, ancestry, stature, and a few other biological characteristics that can help to trace the biological profile of the deceased. Although there is an extensive number of works in the literature on this topic, traditional anthropological methods encounter considerable difficulty in estimating the age of an adult based on skeletal remains. This difficulty increases with aging mainly due to the overlapping of pathological processes. In this study, we tested the reliability of a relatively simple histological methodology to estimate an individual′s age based on tooth roots cementum and developed new equations from individuals with known age and sex. In conclusion, our results confirm the importance of teeth in the estimation of age, suggesting that the proposed method may be effective, especially for younger individuals.Estimating age at death is a key element in the process of human identification of skeletal remains. The interest in dental cementum stems from its increase in thickness throughout life and, at the same time, from the fact it should not be affected by remodeling processes. Since the age assessment is particularly difficult in adults when using traditional anthropological methods on the skeleton, we tested a dental method based on maximum cementum thickness and developed new regression equations. We microscopically analyzed the histological sections of dental roots from a sample of 108 permanent teeth with known age and sex. Age at the time of dental extraction was in the range of 18–84 years. Our findings show that there were no differences in thickness between sexes, dental arch, and mono- and pluriradicular teeth. Separate regression equations were developed for individuals in the whole age range and individuals under 45 years. The equations were then tested on a hold-out sample from the same Mediterranean population demonstrating higher reliability for the equation developed for those under 45. Conversely, due to the increased error in age estimation in individuals over 45, this method should be used with caution in the forensic context when skeletal remains presumably belong to elderly individuals.

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.