Relationship between skeletal maturity indicators and dental calcification stages in a sample pediatric population.

Context: Human growth shows considerable variation. In addition to constitutional differences in the timing of maturation, there are diseases, systemic disorders and environmental factors that may affect a child's physiologic maturity. Interrelationships among skeletal, somatic and sexual maturity have been shown to be consistently strong. The study was conducted to evaluate the relationship between dental calcification stages and skeletal maturity indicators. Materials and Methods: The hand wrist radiographs, the lateral cephalogram and the orthopantomogram (OPG) of 120 patients (60 males and 60 females, age group 8-14 years) were taken. The hand wrist radiographs were analyzed using Fishman's skeletal maturity index (SMI), and the cephalograms analyzed by cervical vertebrae maturation (CVM) by Baccetti. OPG was analyzed according to the Demirjian's system. Result: On assessment, cervical vertebrae maturation indicator (CVMI) staging showed significant results with a correlation coefficient of 0.716 being the highest in canines in males while assessment of dental calcification stages and its comparison with skeletal maturity indicator showed insignificant results. The correlation coefficient values were 0.11, 0.09, 0.09 and 0.13 for canine, first premolar, second premolar and second molar respectively. Conclusion: There is a strong correlation between the maturation stage of cervical vertebrae and calcification stages of canine, first premolar, second premolar and second molar as determined by Demirjian's method.

Aspectos clínicos y forenses del color rosa de los dientes: reporte de un caso / Clinical and forensic aspects of the pink color of teeth: report of a case

La coloración rosa de los dientes puede originarse por diferentes factores. En el ámbito forense se ha descrito al fenómeno denominado post mortem pink teeth como un signo asociado a muertes violentas de etiología diversa. En la práctica clínica también es posible observar pacientes con dientes rosados, fre-cuentemente ocasionados por traumatismos o iatro-genia proveniente de ortodoncia, cuyo mecanismo de producción obedece a distintas etiopatogenias, destacándose las reabsorciones dentinarias inter-nas, cemento-dentinarias externas y calcificaciones dentinarias. El presente artículo expone el caso de un individuo adulto con antecedente de trauma óseo-dentario por accidente vial que, luego de un prolon-gado tiempo, asiste al Servicio de Urgencias Odon-tológicas y Orientación de Pacientes de la Facultad de Odontología de la Universidad de Buenos Aires, en donde se le detecta, a modo de hallazgo exploratorio, una ostensible coloración rosada en el canino infe-rior derecho. La situación motivó un pormenorizado abordaje clínico y radiográfico, indagando respecto a los probables factores que intervinieron en su ge-neración y desarrollo (AU)

The pink coloration of the teeth can be caused by dif-ferent factors. In the forensic field, the phenomenon called post mortem pink teeth has been described as a sign associated with violent deaths of various etiology. In clinical practice, it is also possible to ob-serve patients with pink teeth, frequently caused by trauma or iatrogenesis from orthodontics, whose production mechanism is due to different etiopatho-genesis, highlighting internal dentin resorption, ex-ternal cemento-dentinal resorption and dentin calci-fications. This article presents the case of an adult individual with a history of bone-dental trauma due to a road accident who, after a long time, attends the Dental Emergency and Patient Guidance Service of the Faculty of Dentistry of the University of Bue-nos Aires, where an ostensible pink coloration was detected in the lower right canine as an exploratory finding. The situation motivated a detailed clinical and radiographic approach, inquiring about the probable factors that intervened in its generation and development (AU)

Follicle-stimulating hormone impairs dental pulp stem cells odontogenic differentiation.

In addition to bone, the dentin-pulp complex is also influenced by menopause, showing a decreased regenerative capacity. High levels of follicle-stimulating hormone (FSH) during menopause could directly regulate bone metabolism. Here, the role of FSH in the odontogenic differentiation of the dentin-pulp complex was investigated. Dental pulp stem cells (DPSCs) were isolated. CCK-8 assays, cell apoptosis assays, Western blotting (WB), real-time RT-PCR, alkaline phosphatase activity assays, and Alizarin Red S staining were used to clarify the effects of FSH on the proliferation, apoptosis and odontogenic differentiation of the DPSCs. MAPK pathway-related factors were explored by WB assays. FSH and its inhibitor were used in OVX rats combined with a direct pulp-capping model. HE and immunohistochemistry were used to detect reparative dentin formation and related features. The results indicated that FSH significantly decreased the odontogenic differentiation of the DPSCs without affecting cell proliferation and apoptosis. Moreover, FSH significantly activated the JNK signalling pathway, and JNK inhibitor partly rescued the inhibitory effect of FSH on DPSC differentiation. In vivo, FSH treatment attenuated the dentin bridge formation and mineralization-related protein expression in the OVX rats. Our findings indicated that FSH reduced the odontogenic capacity of the DPSCs and was involved in reparative dentinogenesis during menopause.

Relationship between cervical vertebral maturation and dental development in a sample of yemeni children and adolescents / Relación entre la maduración vertebral cervical y el desarrollo dental en una muestra de niños y adolescentes yemeníes

Objective: This study was conducted to investigate the relationship between dental development and cervical vertebral maturation stages in a group of Yemeni children and adolescents. Materials an Methods: The study included digital panoramic radiographs and lateral skull cephalograms obtained from 207 Yemeni subjects­122 females and 85 males aged between 8 to 18 years. Dental maturity was evaluated according to the method of Demirijian et al., calcification stages of the left mandibular canines, first and second premolars and second molars were assessed. Skeletal maturity was assessed by the cervical vertebral maturation (CVM) stages according to the method of Baccetti et al. Correlation between CVM and dental maturation was evaluated by Spearman rank-order correlation coefficient (SROCC). Results: CVM and dental calcification stages were highly correlated (p<0.001) in both genders, ranging from 0.686 to 0.873 for females and 0.787 to 0.871 for males. Calcification stages of the second molars showed the strongest correlation with CVM. Conclusion: Calcification stages of the second molar may be used as a reliable maturation indicator. Dental maturation may be applied to determine the skeletal maturity status of Yemeni children and adolescents.

Objetivo: Este estudio se realizó para investigar la relación entre el desarrollo dental y las etapas de maduración vertebral cervical en un grupo de niños y adolescentes yemeníes. Material y Métodos: El estudio incluyó radiografías panorámicas digitales y cefalogramas laterales del cráneo obtenidos de 207 sujetos yemeníes: 122 mujeres y 85 hombres de entre 8 y 18 años. La madurez dental se evaluó de acuerdo con el método de Demirijian et al. Se evaluaron las etapas de calcificación de los caninos mandibulares izquierdos, primer y segundo premolares y segundos molares. La madurez esquelética se evaluó mediante las etapas de maduración vertebral cervical (CVM) de acuerdo con el método de Baccetti et al. La correlación entre la CVM y la maduración dental se evaluó mediante el coeficiente de correlación de orden de rango de Spearman (SROCC). Resultado: Las etapas de CVM y calcificación dental estuvieron altamente correlacionadas (p<0.001) en ambos sexos, con un rango de 0.686 a 0.873 para las mujeres y 0.787 a 0.871 para los hombres. Las etapas de calcificación de los segundos molares mostraron la correlación más fuerte con CVM. Conclusión: las etapas de calcificación del segundo molar pueden usarse como un indicador de maduración confiable. La maduración dental puede aplicarse para determinar el estado de madurez esquelética de los niños y adolescentes yemeníes.

Micro-computed tomography imaging reveals the development of a unique tooth mineralization pattern in mackerel sharks (Chondrichthyes; Lamniformes) in deep time.

The cartilaginous fishes (Chondrichthyes) have a rich fossil record which consists mostly of isolated teeth and, therefore, phylogenetic relationships of extinct taxa are mainly resolved based on dental characters. One character, the tooth histology, has been examined since the 19th century, but its implications on the phylogeny of Chondrichthyes is still in debate. We used high resolution micro-CT images and tooth sections of 11 recent and seven extinct lamniform sharks to examine the tooth mineralization processes in this group. Our data showed similarities between lamniform sharks and other taxa (a dentinal core of osteodentine instead of a hollow pulp cavity), but also one feature that has not been known from any other elasmobranch fish: the absence of orthodentine. Our results suggest that this character resembles a synapomorphic condition for lamniform sharks, with the basking shark, Cetorhinus maximus, representing the only exception and reverted to the plesiomorphic tooth histotype. Additionally, †Palaeocarcharias stromeri, whose affiliation still is debated, shares the same tooth histology only known from lamniform sharks. This suggests that †Palaeocarcharias stromeri is member of the order Lamniformes, contradicting recent interpretations and thus, dating the origin of this group back at least into the Middle Jurassic.

The spatiotemporal expression and mineralization regulation of p75 neurotrophin receptor in the early tooth development.

OBJECTIVE: The aim of this study was to investigate the spatiotemporal expression and potential role of p75NTR in tooth morphogenesis and tissue mineralization. MATERIALS AND METHODS: The dynamic morphology of the four stages (from the beginning of E12.5 d, then E13.5 d and E15.5 d, to the end of E18.5 d) was observed, and the expressions of p75NTR and Runx2 were traced. The ectomesenchymal stem cells (EMSCs) were harvested in vitro, and the biological characteristics were observed. Moreover, the mineralization capability of EMSCs was evaluated. The relations between p75NTR and ALP, Col-1 and Runx2 were investigated. RESULTS: The morphologic results showed that the dental lamina appeared at E12.5 d, the bud stage at E13.5 d, the cap stage at E15.5 d and the bell stage at E18.5 d. p75NTR and Runx2 showed the similar expression pattern. EMSCs from the four stages showed no significant difference in proliferation. But the positive rate of p75NTR in the E12.5 d cells was significantly lower than that in the other three stages (P < 0.05). Moreover, the higher positive rate of p75NTR the cells were, the stronger mineralization capability they showed. p75NTR was well positively correlated with the mineralization-related markers ALP, Col-1 and Runx2, which increased gradually with the mature of dental germs. CONCLUSION: p75NTR might play an important role in the regulation of tooth morphogenesis, especially dental hard tissue formation.

Evaluation of the relationship between the Demirjian and Nolla methods and the pubertal growth spurt stage predicted by skeletal maturation indicators in Turkish children aged 10-15: investigation study.

OBJECTIVE: The aim of this study was to investigate the possibility of evaluating the relationship between dental maturation and skeletal maturation without taking a hand-wrist radiogram outside of panoramic radiogram. MATERIALS AND METHODS: Panoramic and hand-wrist radiographs of 717 patients (383 girls and 334 boys), with ages ranging from 10 to 15 years, were evaluated. Dental maturity stages of the mandibular canine, first premolar, second premolar and second molar teeth were determined by Demirjian's and Nolla's methods. The skeletal maturation was determined by Fishman method and bone age was determined through the Greulich and Pyle method. RESULTS: All teeth showed positive and statistically significant correlations, the highest correlation was between the mandibular second premolar calcification stages and hand-wrist maturation stages. According to both dental age determination methods, mandibular second premolar was prominent in determining to the pubertal growth stages. CONCLUSIONS: There was a positive relationship between dental calcification stages and skeletal maturation stages, in the study population. Dental calcification stages of the second mandibular premolar showed the highest positive correlation with the skeletal maturation stages.

IL-33 guides osteogenesis and increases proliferation and pluripotency marker expression in dental stem cells.

OBJECTIVES: Soluble IL-33 (interleukin (IL)-1-like cytokine) acts as endogenous alarm signal (alarmin). Since alarmins, besides activating immune system, act to restore tissue homeostasis, we investigated whether IL-33 exerts beneficial effects on oral stem cell pull. MATERIALS AND METHODS: Clonogenicity, proliferation, differentiation and senescence of stem cells derived from human periodontal ligament (PDLSCs) and dental pulp (DPSCs) were determined after in vitro exposure to IL-33. Cellular changes were detected by flow cytometry, Western blot, immunocytochemistry and semiquantitative RT-PCR. RESULTS: IL-33 stimulated proliferation, clonogenicity and expression of pluripotency markers, OCT-4, SOX-2 and NANOG, but it inhibited ALP activity and mineralization in both PDLSCs and DPSCs. Higher Ki67 expression and reduced ß-galactosidase activity in IL-33-treated cells were demonstrated, whereas these trends were more conspicuous in osteogenic medium. However, after 7-day IL-33 pretreatment, differentiation capacity of IL-33-pretreated cells was retained, and increased ALP activity was observed in both cell types. Results showed that IL-33 regulates NF-κB and ß-catenin signalling, indicating the association of these molecules with changes observed in IL-33-treated PDLSCs and DPSCs, particularly their proliferation, pluripotency-associated marker expression and osteogenesis. CONCLUSIONS: IL-33 treatment impairs osteogenesis of PDLSCs and DPSCs, while increases their clonogenicity, proliferation and pluripotency marker expression. After exposure to IL-33, osteogenic capacity of cells stayed intact. NF-κB and ß-catenin are implicated in the effects achieved by IL-33 in PDLSCs and DPSCs.

Assessment of skeletal maturity using the calcification stages of permanent mandibular teeth.

INTRODUCTION: Knowledge of the growth status of patients is essential to formulate and initiate a precise treatment plan. This study aimed at determining the role of calcification of permanent mandibular teeth for the assessment of skeletal maturity. METHODS: A cross-sectional study was conducted using lateral cephalograms and dental panoramic radiographs of 360 patients (ages 7-18 years) equally divided into six groups according to cervical vertebral maturation stages. Skeletal age was determined using Baccetti et al. method and dental age was calculated using Nolla and Demirjian methods. RESULTS: Mean chronological stage at CS5 revealed a significant difference between male and female subjects (p= 0.003), which showed that the latter achieved skeletal maturity one year earlier than the former. A significant difference (p= 0.007) was found for dental age using Nolla's stages at CS3, which showed females demonstrated a dental age of 1.4 years less than males. Mandibular canine showed the highest correlation with Demirjian index (DI) in males (rho = 0.818) and females (rho = 0.833). Mandibular second premolar showed the highest correlation with Nolla's stages in males (rho = 0.654) and females (rho = 0.664). CONCLUSION: Comparisons between sexes revealed that females are skeletally and dentally advanced. The DI indicated stage F and Nolla's stages identified stages 9, 10 to be indicative of CS2-3 for the mandibular canine and stages F and G and 9-10 for CS2-3 for the first premolars, second premolars and second molars, respectively.

Tooth mineralization and histology patterns in extinct and extant snaggletooth sharks, Hemipristis (Carcharhiniformes, Hemigaleidae)-Evolutionary significance or ecological adaptation?

Shark jaws exhibit teeth that are arranged into distinct series and files and display great diversities in shapes and structures, which not only is related to their function (grasping, cutting, crushing) during feeding, but also bear a strong phylogenetic signal. So far, most research on the relationship between shark teeth and feeding ecology and systematics focused on the external tooth morphology only. Although the tooth histology of sharks has been examined since the early 19th century, its functional and systematic implications are still ambiguous. Shark teeth normally consist of either a porous, cellular dentine, osteodentine (in lamniform sharks and some batoids) or a dense layer of orthodentine (known from different sharks). Sharks of the order Carcharhiniformes, comprising ca. 60% of all extant shark species, are known to have orthodont teeth, with a single exception-the snaggletooth shark, Hemipristis elongata. High resolution micro-CT images of jaws and teeth from selected carcharhiniform sharks (including extant and fossil snaggletooth sharks) and tooth sections of teeth of Hemipristis, other carcharhiniform and lamniform sharks, have revealed that (1) Hemipristis is indeed the only carcharhiniform shark filling its pulp cavity with osteodentine in addition to orthodentine, (2) the tooth histology of Hemipristis elongata differs from the osteodont histotype, which evolved in lamniform sharks and conversely represents a modified orthodonty, and (3) this modified orthodonty was already present in extinct Hemipristis species but the mineralization sequence has changed over time. Our results clearly show the presence of a third tooth histotype-the pseudoosteodont histotype, which is present in Hemipristis. The unique tooth histology of lamniform sharks might provide a phylogenetic signal for this group, but more research is necessary to understand the phylogenetic importance of tooth histology in sharks in general.

Assessment of skeletal maturity using the calcification stages of permanent mandibular teeth

Abstract Introduction: Knowledge of the growth status of patients is essential to formulate and initiate a precise treatment plan. This study aimed at determining the role of calcification of permanent mandibular teeth for the assessment of skeletal maturity. Methods: A cross-sectional study was conducted using lateral cephalograms and dental panoramic radiographs of 360 patients (ages 7-18 years) equally divided into six groups according to cervical vertebral maturation stages. Skeletal age was determined using Baccetti et al. method and dental age was calculated using Nolla and Demirjian methods. Results: Mean chronological stage at CS5 revealed a significant difference between male and female subjects (p= 0.003), which showed that the latter achieved skeletal maturity one year earlier than the former. A significant difference (p= 0.007) was found for dental age using Nolla's stages at CS3, which showed females demonstrated a dental age of 1.4 years less than males. Mandibular canine showed the highest correlation with Demirjian index (DI) in males (rho = 0.818) and females (rho = 0.833). Mandibular second premolar showed the highest correlation with Nolla's stages in males (rho = 0.654) and females (rho = 0.664). Conclusion: Comparisons between sexes revealed that females are skeletally and dentally advanced. The DI indicated stage F and Nolla's stages identified stages 9, 10 to be indicative of CS2-3 for the mandibular canine and stages F and G and 9-10 for CS2-3 for the first premolars, second premolars and second molars, respectively.

Resumo Introdução: o conhecimento acerca do status de crescimento dos pacientes é essencial para se formular e iniciar um plano de tratamento preciso. Esse estudo teve como meta determinar a correlação entre a calcificação dos dentes inferiores permanentes e a avaliação da maturação esquelética. Métodos: um estudo transversal foi conduzido utilizando-se radiografias laterais e panorâmicas das arcadas de 360 pacientes (idades entre 7 e 18 anos), igualmente divididos em seis grupos, de acordo com os estágios de maturação esquelética das vértebras cervicais. A idade esquelética foi determinada utilizando-se o método de Baccetti, e a idade dentária foi calculada utilizando-se os métodos de Nolla e Demirjian. Resultados: o estágio cronológico médio em CS5 revelou uma diferença significativa entre os indivíduos do sexo masculino e do feminino (p= 0,003), demonstrando que as meninas alcançavam a maturação esquelética um ano antes dos meninos. Encontrou-se uma diferença significativa (p= 0,007) para a idade dentária utilizando-se os estágios de Nolla em CS3, o que revelou que as meninas exibiam uma idade dentária 1,4 anos inferior à dos meninos. Os caninos inferiores demonstraram a maior correlação com o índice de Demirjian (DI) tanto em indivíduos do sexo masculino (rho = 0,818) quanto do feminino (rho = 0,833). Já os segundos pré-molares inferiores revelaram a maior correlação com os estágios de Nolla, tanto em meninos (rho = 0,654) quanto em meninas (rho = 0,664). Conclusão: as comparações entre os sexos revelaram que as mulheres são mais precoces tanto no desenvolvimento dentário quanto no esquelético. O DI indicou o estágio F, e o método de Nolla identificou os estágios 9 e 10 como indicativos de CS2-3, para os caninos inferiores; e os estágios F e G, e 9 e 10 para CS2-3, para os primeiros e segundos pré-molares, e segundos molares, respectivamente.

Estimating age and the probability of being at least 18 years of age using third molars: a comparison between Black and White individuals living in South Africa.

Third molar development of 705 White and 563 Black South African individuals aged between 15 and 25 years was assessed from panoramic radiographs obtained from the School of Dentistry, University of Pretoria, South Africa. The maxillary and mandibular left third molars were scored according to a ten-stage scoring system. Ancestry and sex differences in dental maturity were assessed, and the likelihood of an individual being 18 years of age was determined for each developmental stage. Statistically significant differences were noted among ancestry groups for most developmental stages, with South African Black individuals consistently maturing earlier than the White individuals. Statistically significant differences were noted among sex groups for some of the stages, mostly those near the final stages of root development. The results indicate that male third molars completed their development faster than that of females. The likelihood of an individual being 18 years of age based on the third molar development stage for the maxilla and mandible on its own was also determined. Combined likelihood results, for the maxillary and mandibular left third molars for stage H, increased the likelihood of being 18 years to 95% for all the studied ancestry and sex groups.

Fam83h mutation inhibits the mineralization in ameloblasts by activating Wnt/ß-catenin signaling pathway.

FAM83H was identified as the major causative gene for autosomal dominant hypocalcified amelogenesis imperfect (ADHCAI). The pathogenic mechanism of FAM83H in ADHCAI remains elusive. The present study aims to investigate the effect of Fam83h mutation on the mineralization of mouse ameloblast cell line LS8 and to explore the possible pathogenesis of ADHCAI. Lentivirus package was performed for the plasmids with mouse Fam83h mutant cDNA (c.1186C > T, M3) and empty vector (Control) and transfected into LS8, which were divided into M3-FLAG and Control groups. Immunoprecipitation, western-blot and immunofluorescence were performed to detect the expression and subcellular localization of Fam83 h, CK1α and ß-catenin. ALP activity, ALP staining, expression of the mineralization factors were detected in two groups during mineralization induction. Expression of the mineralization factors was also detected in M3-FLAG and LS8 exposing to pyrvinium pamoate. Compared with the Control, the Fam83h mutation altered the expression and localization of Fam83 h, CK1α and ß-catenin in LS8, inhibited the mineralization and down-regulated the expression of mineralization factors in M3-FLAG. Pyrvinium pamoate, an inhibitor of the Wnt/ß-catenin signaling pathway, up-regulated expression of mineralization factors in LS8 and rescued the inhibited mineralization in M3-FLAG. The results indicated that the Fam83h mutation could inhibit the mineralization in ameloblasts by activating Wnt/ß-catenin signaling pathway.

Bone Morphogenetic Protein 2 Coordinates Early Tooth Mineralization.

Formation of highly organized dental hard tissues is a complex process involving sequential and ordered deposition of an extracellular scaffold, followed by its mineralization. Odontoblast and ameloblast differentiation involves reciprocal and sequential epithelial-mesenchymal interactions. Similar to early tooth development, various Bmps are expressed during this process, although their functions have not been explored in detail. Here, we investigated the role of odontoblast-derived Bmp2 for tooth mineralization using Bmp2 conditional knockout mice. In developing molars, Bmp2LacZ reporter mice revealed restricted expression of Bmp2 in early polarized and functional odontoblasts while it was not expressed in mature odontoblasts. Loss of Bmp2 in neural crest cells, which includes all dental mesenchyme, caused a delay in dentin and enamel deposition. Immunohistochemistry for nestin and dentin sialoprotein (Dsp) revealed polarization defects in odontoblasts, indicative of a role for Bmp2 in odontoblast organization. Surprisingly, pSmad1/5/8, an indicator of Bmp signaling, was predominantly reduced in ameloblasts, with reduced expression of amelogenin ( Amlx), ameloblastin ( Ambn), and matrix metalloproteinase ( Mmp20). Quantitative real-time polymerase chain reaction (RT-qPCR) analysis and immunohistochemistry showed that loss of Bmp2 resulted in increased expression of the Wnt antagonists dickkopf 1 ( Dkk1) in the epithelium and sclerostin ( Sost) in mesenchyme and epithelium. Odontoblasts showed reduced Wnt signaling, which is important for odontoblast differentiation, and a strong reduction in dentin sialophosphoprotein ( Dspp) but not collagen 1 a1 ( Col1a1) expression. Mature Bmp2-deficient teeth, which were obtained by transplanting tooth germs from Bmp2-deficient embryos under a kidney capsule, showed a dentinogenesis imperfecta type II-like appearance. Micro-computed tomography and scanning electron microscopy revealed reduced dentin and enamel thickness, indistinguishable primary and secondary dentin, and deposition of ectopic osteodentin. This establishes that Bmp2 provides an early temporal, nonredundant signal for directed and organized tooth mineralization.

Abrogation of Fam20c altered cell behaviors and BMP signaling of immortalized dental mesenchymal cells.

FAM20C mutations compromise the mineralization of skeleton and tooth in both human and mouse. Putatively, the mineralization disorder is attributed to the elevated fibroblast growth factor 23 (FGF23), which reduced the serum phosphorus by suppressing the reabsorption of phosphorus in kidney. Besides the regulation on systemic phosphorus homeostasis, FAM20C was also implicated to regulate cell behaviors and gene expression through a cell-autonomous manner. To identify the primary effects of Fam20c on dental mesenchymal cells, mouse Fam20c-deficient dental mesenchymal cells were generated by removing the floxed alleles from the immortalized mouse Fam20cf/f dental mesenchymal cells with Cre-expressing lentivirus. The removal of Fam20c exerted no impact on cell morphology, but suppressed the proliferation and mobility of the dental mesenchymal cells. Fam20c deficiency also significantly reduced the expression of Osterix, Runx2, type I Collagen a 1 (Col1a1), Alkaline phosphatase (Alpl) and the members of the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family, but increased Fgf23 expression. Consistently, the in vitro mineralization of Fam20c-deficient dental mesenchymal cells was severely disabled. However, supplements of the non-collagenous proteins from wild type rat dentin failed to rescue the compromised mineralization, suggesting that the roles of FAM20C in tooth mineralization are more than phosphorylating local matrices and regulating systemic phosphorus metabolism. Moreover, the down-regulated BMP signaling pathways in the Fam20c deficient dental mesenchymal cells revealed that the kinase activity of FAM20C might be required to maintain BMP signaling. In summary, our study discloses that Fam20c indeed regulates cell behaviors and cell signaling pathway in a cell-autonomous manner.

Histological and chemical analyses of mesiodens development and mineralization.

OBJECTIVE: This study aimed to compare the developmental timing and mineralization quality of mesiodentes, i.e., supernumerary teeth located mainly in the midline of the maxilla between the central incisors, with the developmental timing and mineralization quality of permanent and primary central incisors. DESIGN: Sixteen mesiodentes, nine permanent and seven primary central incisors were collected. The location of the neonatal line was determined using a light microscope at 10× or 20× enlargements. Chemical composition of the enamel at two locations was analyzed using energy dispersive X-ray spectrometer. RESULTS: Neonatal lines were observed in eight out of 16 mesiodentes, in all primary central incisors and in none of the permanent central incisors. Chemical analyses showed that mesiodentes mineralization was impaired, resulting in higher amount of organic ions and reduced inorganic ions. Discriminant analysis showed minimal overlap of mesiodentes with either primary or permanent centrals. CONCLUSIONS: Mesiodentes development begins before birth in 50% of the cases but later than the primary centrals. Mineralization of mesiodens is impaired with less mineral content and higher organic content. The results showed that mesiodentes are a special group of teeth with defective morpho-differentiation and mineralization, with little similarity to primary or permanent central incisors.

Accuracy of dental development for estimating the pubertal growth spurt in comparison to skeletal development: a systematic review and meta-analysis.

OBJECTIVES: This study aimed to search for scientific evidence concerning the accuracy of dental development for estimating the pubertal growth spurt. METHODS: It was conducted according to the statements of PRISMA. An electronic search was performed in six databases, including the grey literature. The PICOS strategy was used to define the eligibility criteria and only observational studies were selected. RESULTS: Out of 1,416 identified citations, 10 articles fulfilled the criteria and were included in this systematic review. The association between dental development and skeletal maturity was considered strong in seven studies, and moderate in two, although the association with the pubertal growth spurt had been verified in only four articles. According to half of the studies, the tooth that provided the greater association with the ossification centres was the lower canine. The meta-analysis performed also indicated a positive association, being stronger in females [0.725 (0.649-0.808)]. However, when the method used for dental evaluation was considered, it was possible to verify greater correlation coefficients for Nolla [0.736 (0.666-0.814)] than for Demirjian [0.631 (0.450-0.884)], at the boys sample. The heterogeneity test reached high values (Q = 51.00), suggesting a potential bias within the studies. CONCLUSIONS: Most of individual studies suggested a strong correlation between dental development and skeletal maturation, although the association with the peakof pubertal growth spurtwas clearly cited only in some of them. However, due to the high heterogeneity found among the studies included in this meta-analysis, a pragmatic recommendation about the use of dental stages is not possible.

Three-dimensional analysis of third molar development to estimate age of majority.

Third molars are one of the few biological markers available for age estimation in undocumented juveniles close the legal age of majority, assuming an age of 18years as the most frequent legal demarcation between child and adult status. To obtain more accurate visualization and evaluation of third molar mineralization patterns from computed tomography images, a new software application, DentaVol©, was developed. Third molar mineralization according to qualitative (Demirjian's maturational stage) and quantitative parameters (third molar volume) of dental development was assessed in multi-slice helical computed tomography images of both maxillary arches displayed by DentaVol© from 135 individuals (62 females and 73 males) aged between 14 and 23years. Intra- and inter-observer agreement values were remarkably high for both evaluation procedures and for all third molars. A linear correlation between third molar mineralization and chronological age was found, with third molar maturity occurring earlier in males than in females. Assessment of dental development with both procedures, by using DentaVol© software, can be considered a good indicator of age of majority (18years or older) in all third molars. Our results indicated that virtual computed tomography imaging can be considered a valid alternative to orthopantomography for evaluations of third molar mineralization, and therefore a complementary tool for determining the age of majority.

Relationship between dental calcification and skeletal maturation in a Peruvian sample.

OBJECTIVE:: the objective of the study was to determine the relationship between dental calcification stages and skeletal maturation in a Peruvian sample. METHODS:: panoramic, cephalometric and carpal radiographs of 78 patients (34 girls and 44 boys) between 7 and 17 years old (9.90 ± 2.5 years) were evaluated. Stages of tooth calcification of the mandibular canine, first premolar, second premolar, and second molar and the skeletal maturation with a hand-wrist and a cervical vertebrae method were assessed. The relationships between the stages were assessed using Spearman's correlation coefficient. Additionally, the associations of mandibular and pubertal growth peak stages with tooth calcification were evaluated by Fisher's exact test. RESULTS:: all teeth showed positive and statistically significant correlations, the highest correlation was between the mandibular second molar calcification stages with hand-wrist maturation stages (r = 0.758, p < 0.001) and with vertebrae cervical maturation stages (r = 0.605, p < 0.001). The pubertal growth spurt was found in the G stage of calcification of the second mandibular molar, and the mandibular growth peak was found in the F stage of calcification of the second molar. CONCLUSION:: there was a positive relationship between dental calcification stages and skeletal maturation stages by hand-wrist and cervical vertebrae methods in the sample studied. Dental calcification stages of the second mandibular molar showed the highest positive correlation with the hand-wrist and cervical vertebrae stages.

Chronology of mineralization of the permanent mandibular second molar teeth and forensic age estimation.

Forensic age estimation frequently relies upon the chronology of mineralization of the third molar teeth. However, even when present, third molar teeth cannot always be used for estimating age in people who are classified as minors. Seconds molars develop earlier and in a more predictable way, and therefore are often more reliable for age estimation in this age group. This study aims to contribute to forensic age estimation using an age threshold of 14-years, studying the stages of development of permanent mandibular second molar teeth mineralization. 367 orthopantograms of a Portuguese population group, aged between 3 and 19 years, were studied. The stages of mineralization of mandibular permanent second molar teeth were studied following the classification stages proposed by Demirjian et al. Stage descriptive analysis was performed, and associations between age and stage were studied. A logistic regression to determine age over 14 years, using maturation stages and sex as a predictive variables, was made. A second sample was used for testing the model. The significance level was set at 5%. The model correctly classified 92.0% of cases overall. The equation was tested in the second sample, and the results showed that there were no statistical significant differences between the binary real age (i.e. age < 14 and age ≥ 14 years) and the estimated age (p = 0.109). The developed model is useful for age estimation using 14-years as a threshold. However, stage maturation analyses showed that stage F, in males, and stages G and H, in both sexes, lead to an estimated age with significant statistical differences from chronological age.