Development of undergraduate students' diagnostic accuracy for the classification of molar incisor hypomineralization.

INTRODUCTION: One of the major difficulties with respect to molar incisor hypomineralization (MIH) is its classification and differentiation from other enamel development defects (EDDs). The aim of this study was to evaluate diagnostic accuracy in dental students to classify MIH as well as its differentiation from other EDDs by combining conventional theoretical classes and e-learning-assisted pre-clinical practices. METHODS: In this one-group pre-test and post-test study, 59 second-year students assessed 115 validated photographs using the MIH Index on the Moodle learning platform. This index assesses the clinical features and extent of MIH, differentiating it from other EDDs. Students received automatic feedback after the pre-test. Two weeks later, students re-evaluated the same photographs. Both pairwise accuracy and overall diagnostic accuracy were estimated and compared for pre- and post-testing, with the area under the curve AUC, along with 95% confidence intervals (95% CI). RESULTS: The lowest diagnostic accuracy was for the ability to discriminate between white or cream-coloured demarcated opacities and hypomineralization-type defect that is not MIH. The overall pre-test accuracy was AUC = 0.83 and increased significantly post-test to AUC = 0.99 (p < .001). The overall accuracy to discriminate the extent of the lesion also increased significantly post-test (p < .001). CONCLUSION: Diagnostic skills to classify MIH can be developed by combining conventional theoretical classes and e-learning-assisted pre-clinical practices.

Artificial intelligence system for training diagnosis and differentiation with molar incisor hypomineralization (MIH) and similar pathologies.

OBJECTIVES: Molar incisor hypomineralization (MIH) is a difficult-to-diagnose developmental disorder of the teeth, mainly in children and adolescents. Due to the young age of the patients, problems typically occur with the diagnosis of MIH. The aim of the present technical note was to investigate whether a successful application of a neural network for diagnosis of MIH and other different pathologies in dentistry is still feasible. MATERIALS AND METHODS: For this study, clinical pictures of four different pathologies were collected (n = 462). These pictures were categorized in caries (n = 118), MIH (n = 115), amelogenesis imperfecta (n = 112) and dental fluorosis (n = 117). The pictures were anonymized and a specialized dentist taking into account all clinical data did the diagnosis. Then, well-investigated picture classifier neural networks were selected. All of these were convolutional neural networks (ResNet34, ResNet50, AlexNet, VGG16 and DenseNet121). The neural networks were pre-trained and transfer learning was performed on the given datasets. RESULTS: For the vgg16 network, the precision is the lowest with 83.98% as for the dense121 it shows the highest values with 92.86%. Comparing the different pathologies between the investigated neural networks, there is no trend detectable. CONCLUSION: In the long term, an implementation of artificial intelligence for the detection of specific dental pathologies is conceivable and sensible. CLINICAL RELEVANCE: Finally, this application can be integrated in the area of training and teaching in order to teach dental students as well as general practitioners for MIH and similar dental pathologies.

Singleton-Merten syndrome: A rare cause of femoral head necrosis.

Singleton-Merten syndrome (SMS) is a type I interferonopathy. In this report, we disclose the first-to the best of our knowledge-direct association of SMS with femoral head necrosis (FHN). The following case report presents the condition of a 38-year-old male suffering from SMS with FHN, characterized by acute symptoms and rapid disease progression. As per the recommendations of the Association Research Circulation Osseous (ARCO) and the S3-guidelines, we successfully treated the FHN with core decompression. Our histological results correlate with the changes described in medical literature in patients with SMS and MDA5-knockout in vivo experiments such as osteopenia, widened medullary cavity, and thin cortical bone. Moreover, the conducted immunohistochemistry shows strong CD56 positivity of the osteoblasts and osteocytes, as well as significant CD68 and CD163 positivity of the middle-sized osteoclasts. Collectively, these findings suggest an underlying syndrome in the FHN. A six-month post-operative follow-up revealed complete recovery with the absence of the initial symptoms and ability to resume normal daily activities. Taken together, our findings suggest that SMS is an additional cause of FHN in young adults. Early detection and adequate treatment using well-established joint-preserving techniques demonstrate a favorable improvement of the patient's clinical condition.

An integrative approach to studying plasticity in growth disruption and outcomes: A bioarchaeological case study of Napoleonic soldiers.

OBJECTIVES: The aim of this study was to investigate how much variation in adult stature and body mass can be explained by growth disruption among soldiers who served in Napoleon's Grand Army during the Russian Campaign of 1812. METHODS: Linear enamel hypoplasia (LEH) were recorded as representations of early life growth disruption, while the impact on future growth was assessed using maximum femur length (n = 73) as a proxy for stature and maximum femoral head diameter (n = 25) as a proxy for body mass. LEH frequency, severity, age at first formation, and age at last formation served as explanatory variables in a multiple regression analysis to test the effect of these variables on maximum femur length and maximum femoral head diameter. RESULTS: The multiple regression model produced statistically significant results for maximum femur length (F-statistic = 3.05, df = 5 and 67, P = .02), with some variation in stature (adjusted r2 = 0.13) attributable to variation in growth disruption. The multiple regression model for maximum femoral head diameter was not statistically significant (F-statistic = 1.87, df = 5 and 19, P = .15). CONCLUSIONS: We hypothesized stress events during early life growth and development would have significant, negative, and cumulative effects on growth outcomes in adulthood. The results did not support our hypothesis. Instead, some variables and interactions had negative effects on stature, whereas others had positive effects. This is likely due to catch-up growth, the relationship between acute and chronic stress and growth, resilience, and plasticity in human growth over the life course.

Faster growth corresponds with shallower linear hypoplastic defects in great ape canines.

Deeper or more 'severe' linear enamel hypoplasia (LEH) defects are hypothesized to reflect more severe stress during development, but it is not yet clear how depth is influenced by intrinsic enamel growth patterns. Recent work documented inter- and intraspecific differences in LEH defect depth in extant great apes, with mountain gorillas having shallower defects than other taxa, and females having deeper defects than males. Here, we assess the correspondence of inter- and intraspecific defect depth and intrinsic aspects of enamel growth: enamel extension rates, outer enamel striae of Retzius angles, and linear enamel thickness. Thin sections of great ape canines (n = 40) from Gorilla beringei beringei, Gorilla gorilla gorilla, Pan troglodytes, and Pongo spp. were analyzed. Enamel extension rates were calculated within deciles of enamel-dentine junction length. Linear enamel thickness and the angle of intersection between striae of Retzius and the outer enamel surface were measured in the imbricational enamel. Mountain gorillas have faster enamel extension rates and shallower striae angles than the other taxa examined. Mountain gorillas have thinner imbricational enamel than western lowland gorillas and orangutans, but not chimpanzees. In the combined-taxon sample, females exhibit larger striae angles and thicker imbricational enamel than males. Enamel extension rates are highly negatively correlated with striae angles and LEH defect depth. Enamel growth variation corresponds with documented inter- and intraspecific differences in LEH defect depth in great ape canines. Mountain gorillas have shallower striae angles and faster extension rates than other taxa, which might explain their shallow LEH defect morphology and the underestimation of their LEH prevalence in previous studies. These results suggest that stressors of similar magnitude and timing might produce defects of different depths in one species or sex vs. another, which has implications for interpretations of stress histories in hominins with variable enamel growth patterns.

Bioarchaeological evidence for adaptive plasticity and constraint: Exploring life-history trade-offs in the human past.

The Developmental Origins of Health and Disease paradigm evaluates the consequences of early life stress on health at later stages of life. Interacting with this paradigm represents a profound opportunity to leverage the lifespan and contextual approaches to human skeletal remains adopted by bioarchaeological research. Teeth and bone provide evidence for stressors experienced early in life. These events represent evidence for adaptive plasticity as Individuals survive the events through reallocation of energy to essential physiological functions, which inhibits enamel and skeletal growth. Age-at-death, adult body size, chronic infection, or childhood mortality may be used as covariates to better understand the physiological constraints operating on individual bodies following survival of early life stress. Contextual evidence from cemeteries provides clues to the ecological and cultural contingencies that exacerbate or mitigate the expression of these trade-offs. Future studies should incorporate newly derived methods that provide reproducible and precise ways to evaluate early life stress, while incorporating populations that are often neglected.

miR-675 promotes odontogenic differentiation of human dental pulp cells by epigenetic regulation of DLX3.

In a previous study, we showed that microRNA-675 (miR-675) was significantly down-regulated in patients with tricho-dento-osseous (TDO) syndrome. One of the main features of TDO syndrome is dentin hypoplasia. Thus, we hypothesize that miR-675 plays a role in dentin development. In this study, we determined the role of miR-675 in the odontogenic differentiation of human dental pulp cells (hDPCs). Stable overexpression and knockdown of miR-675 in hDPCs were performed using recombinant lentiviruses containing U6 promoter-driven miR-675 and short hairpin-miR675 expression cassettes, respectively. Alkaline phosphatase (ALP) assay, Alizarin red staining assay, quantitative polymerase chain reaction (qPCR), Western blot analysis, and immunofluorescent staining revealed the promotive effects of miR-675 on the odontogenic differentiation of hDPCs. Further, we found that miR-675 facilitates the odontogenic differentiation process of hDPCs by epigenetic regulation of distal-less homeobox (DLX3). Thus, for the first time, we determined that miR-675 regulates the odontogenic differentiation of hDPCs by inhibiting the DNA methyltransferase 3 beta (DNMT3B)-mediated methylation of DLX3. Our findings uncover an unanticipated regulatory role for miR-675 in the odontogenic differentiation of hDPCs by epigenetic changes in DLX3 and provide novel insight into dentin hypoplasia feature in TDO patients.

New distance-based exponential regression method and equations for estimating the chronology of linear enamel hypoplasia (LEH) defects on the anterior dentition.

OBJECTIVES: We present a new distance-based exponential regression approach based on published histological data to refine the objectivity, accuracy, and precision of age estimates of LEH defect formation on the anterior dentition. METHODS: Published histological data of anterior tooth crown growth for two samples (northern European and southern African) were fitted with exponential trendlines to construct exponential regression equations for each tooth type. A theoretical comparison of the age estimates produced by two commonly used methods (decile chart and linear regression), and those based on the exponential regression equations presented in this article were undertaken. Paired-samples t-tests were used to determine whether the estimates obtained by these methods differed significantly. RESULTS: Exponential regression equations were able to accurately replicate age estimates produced by the decile-chart method. For defects that fell precisely on a decile, estimates differed by 1-23 days. Estimates based on the linear regression method were consistently younger by 4.5-16 months. For defects that fell within deciles, the exponential regression equation estimates, when different, were 12 days to 4 months older than those yielded by the decile method. CONCLUSIONS: By combining currently published histological data on anterior tooth crown growth with a regression approach, it is possible to produce more accurate age estimates than yielded by methods that do not rely on histological data. Furthermore, this approach also greatly improves the objectivity, precision and replicability of results, especially for defects that fall between deciles, when compared to the decile chart method.

Neandertal features of the deciduous and permanent teeth from Portel-Ouest Cave (Ariège, France).

OBJECTIVES: We describe 14 unpublished and nine published teeth from the Mousterian level of Portel-Ouest (Ariège, France), dated to 44 ka. In a comparative context, we explore the taxonomical affinities of those teeth with Neandertals and modern humans which are both known to exist at that time. We further make some paleobiological inferences about this human group. METHODS: The comparative analysis of Neandertals and modern humans is based on nonmetric traits at the outer enamel surface and the enamel-dentine junction, crown diameters and three-dimensional (3D) enamel thickness measurements of lower permanent teeth. The crown and roots are explored in detail based on the µCT-scan data to identify the multiple criteria involved in the paleobiological approach. RESULTS: Nonmetric traits and 3D enamel thickness tend to be more similar to Neandertals than modern humans, notably for C1 , P4 , and M2 (included in all analyses) as well as volume of the pulp cavity in roots of the anterior permanent teeth. The Portel-Ouest sample corresponds to a minimum of seven juveniles, one or two adolescents and one adult, which exhibit recurrent linear enamel hypoplasia (up to five events for one individual), the torsiversion of one anterior tooth and irregular oblique wear in some anterior deciduous teeth. DISCUSSION: This morphological study confirms that the remains from Portel-Ouest are Neandertals, associated with a Mousterian complex. Furthermore, we found the expected pattern of mortality and stress for a Neandertal group, that is, various age categories and developmental defects (nonexclusive to Neandertals), while adults are underrepresented and juveniles are overrepresented. Further excavations would contribute finding new remains and maybe complete this demographic profile.

The intersections of industrialization: Variation in skeletal indicators of frailty by age, sex, and socioeconomic status in 18th- and 19th-century England.

OBJECTIVES: Intersectionality theory argues that various categories of identity and forms of systemic oppression interact and produce inequalities in resource access, economic opportunities, and health outcomes. However, there has been little explicit engagement with this theory by bioarchaeologists examining disparate health outcomes in the past. This study examines the associations among frailty, age at death, sex, and socioeconomic status (SES) in 18th- and 19th-century England. MATERIALS AND METHODS: The sample for this study comes from four industrial-era cemeteries from England, ca. 1711-1857. The associations among adult age (18+ years), SES, sex, and three skeletal indicators of stress (dental enamel hypoplasia [DEH, n = 293], cribra orbitalia [CO, n = 457], periosteal lesions [PNB, n = 436]) are examined using hierarchical log-linear analysis. RESULTS: Significant interactions existed among the variables examined for two skeletal indicators: high SES females had lower frequencies of CO relative to other groups and males between ages 30-45 years exhibited higher frequencies of PNB compared to females or males of older or younger ages, regardless of SES. Additionally, sex and SES were consistently associated with age at death. CONCLUSIONS: These results suggest that patterns of stress indicators cannot be examined solely across unilateral axes of age, SES, or sex. Intersecting axes of privilege, marginalization, and structural oppression may have buffered high SES females from some negative health outcomes (CO) while predisposing them to others (risk of maternal mortality). Likewise, the hazardous working conditions relegated to adult males may have heightened the risk of injury, infection, and death for middle-aged men in industrial-era England.

On the Variable Clinical Presentation of Molar-Incisor Hypomineralization.

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Original reports on the etiology of the condition and possible risk factors were inconclusive, and we refuted the original suggestion that MIH is an idiopathic condition and suggested that MIH has complex inheritance and is due to the interaction of more than one gene and the environment. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. Later we expanded this work to include genes related to the immune response. In this report, we provide a rationale to explain the variation seen in the clinical presentation of MIH, which can affect just one molar out of the four or just a portion of a particular molar.

Breakdown of demarcated opacities related to molar-incisor hypomineralization: a longitudinal study.

OBJECTIVES: This prospective longitudinal study aimed to evaluate if the occurrence of post-eruptive breakdown of demarcated opacities in hypomineralized teeth is influenced by the color or location of the opacity. MATERIALS AND METHODS: Patients diagnosed with molar-incisor hypomineralization (MIH) between 2012 and 2014 were eligible. Two calibrated examiners performed the initial and follow-up evaluations according to European Academy of Paediatric Dentistry (EAPD) criteria. Sixty-five patients were included. Fifty-eight (89.2%), with a mean age of 8.8 years (SD: 1.4), were reassessed after 1 year. Two hundred and nine of 1155 tooth surfaces were considered for the study: 86 with white opacity (OP-W), 91 with yellow opacity (OP-Y), and 32 with enamel breakdown (EB). RESULTS: From the OP-W, OP-Y, and EB, 14, 27.5, and 46.9% worsened to breakdown exposing dentin, atypical restoration, or extraction (DB + RA or EXT), respectively. Yellow opacities tended to be more prone to breakdown than white opacities. The occurrence of EB, DB + AR, or EXT was not influenced by the location (p = 0.25). CONCLUSIONS: The color of the opacity seems to play an important role on the occurrence of fracture and should be considered as a potential predictor. CLINICAL RELEVANCE: Dentists should be aware that demarcated opacities related to MIH tend to fracture over time. Moreover, children with MIH should be seen at shorter intervals.

Trauma in primary teeth and its effect on the development of permanent successors: a controlled study.

Objective: This controlled study investigated the occurrence of sequelae to permanent successors (SPS) following traumatic dental injury in primary teeth (TDIp). Additionally, this study evaluated whether TDIp is a risk factor for SPS, with a focus on an association between SPS and the child's age and type of trauma. Materials and methods: The trauma group (TG) consisted of permanent teeth, whose antecessors had suffered TDIp, in a population of children with complete eruption of permanent teeth. The control group (CG) consisted of permanent teeth from the same individuals, whose antecessors had not suffered TDIp. There were 214 cases of TDIp with their respective permanent teeth. In the CG 247 permanent teeth, whose antecessor had not suffered TDIp, were included. Data concerning such teeth and when TDIp occurred (in terms of the child's age) and types of SPS were collected. The chi-square test, regression logistic with generalized estimating equations (GEE) test, and risk analyses were applied to investigate the associations. Results: Overall, 29% of the permanent teeth in the TG presented SPS. This was compared to the development disturbances in the CG, which was 7%. The TG demonstrated the highest risk for SPS (OR, 5.388; p = .0001). The discolouration of enamel (37%) was the most common type of SPS found. SPS was more prone to occur in permanent teeth whose antecessors had been intruded (39%; p < .001). TDIp when the child was 1-year old was associated with SPS (p < .001). Moreover, children who had TDIp had a 4.1 times higher risk of presenting SPS. Conclusions: TDIp is a risk factor for the development of SPS. All types of TDIp caused SPS in this research. Additionally, the younger ages at the time of the injury and intrusions were related to SPS.

Mutations in DDX58, which encodes RIG-I, cause atypical Singleton-Merten syndrome.

Singleton-Merten syndrome (SMS) is an autosomal-dominant multi-system disorder characterized by dental dysplasia, aortic calcification, skeletal abnormalities, glaucoma, psoriasis, and other conditions. Despite an apparent autosomal-dominant pattern of inheritance, the genetic background of SMS and information about its phenotypic heterogeneity remain unknown. Recently, we found a family affected by glaucoma, aortic calcification, and skeletal abnormalities. Unlike subjects with classic SMS, affected individuals showed normal dentition, suggesting atypical SMS. To identify genetic causes of the disease, we performed exome sequencing in this family and identified a variant (c.1118A>C [p.Glu373Ala]) of DDX58, whose protein product is also known as RIG-I. Further analysis of DDX58 in 100 individuals with congenital glaucoma identified another variant (c.803G>T [p.Cys268Phe]) in a family who harbored neither dental anomalies nor aortic calcification but who suffered from glaucoma and skeletal abnormalities. Cys268 and Glu373 residues of DDX58 belong to ATP-binding motifs I and II, respectively, and these residues are predicted to be located closer to the ADP and RNA molecules than other nonpathogenic missense variants by protein structure analysis. Functional assays revealed that DDX58 alterations confer constitutive activation and thus lead to increased interferon (IFN) activity and IFN-stimulated gene expression. In addition, when we transduced primary human trabecular meshwork cells with c.803G>T (p.Cys268Phe) and c.1118A>C (p.Glu373Ala) mutants, cytopathic effects and a significant decrease in cell number were observed. Taken together, our results demonstrate that DDX58 mutations cause atypical SMS manifesting with variable expression of glaucoma, aortic calcification, and skeletal abnormalities without dental anomalies.

Deep infiltration for the treatment of hypomineralized enamel lesions in a patient with molar incisor hypomineralization: a clinical case.

This case report presents the technique of deep infiltration for the treatment of hypomineralized enamel lesions in a patient affected by molar incisor hypomineralization (MIH) with the purpose of obtaining an aesthetic improvement in the affected vestibular enamel. Deep infiltration treatment involves a sequence of steps starting with an initial mechanical abrasion of the outside surface of the enamel, followed by a phase of chemical erosion using 15% hydrochloric acid, penetration through the porosity of the enamel by a very fluid resin, and finally the repair of the thin layer of lost enamel using a composite. The aesthetic improvement of the elements affected by hypomineralized lesions is discernible immediately following treatment and becomes more accentuated with time. At the expense of minimal damage to surface enamel, deep infiltration enables treatment of all types of white spot enamel lesions, regardless of aetiology, offering the possibility of restoring an aesthetically pleasing smile for patients.

"Superficial infiltration to treat white hypomineralized defects of enamel: clinical trial with 12-month follow-up.

Hypomineralization represents one of the most common defects in tooth crowns. Thanks to a wide understanding of aesthetics, patients request a treatment to resolve these defects. Different techniques are available, such as crowns/veneers, traditional restorative treatments, microabrasion, whitening, remineralizing agents and infiltration technique. The objective of this trial is to assess the effectiveness of superficial infiltration with Icon (DMG, Hamburg, Germany) on the attenuation of crown hypomineralized lesions of various etiological origins with a 12-month follow-up. Seventeen patients with white defects of enamel in the aesthetic sector were selected. The infiltration procedure was carried out following the manufacturer's instructions. Intraoral photographs were taken before and directly after treatment in order to document the immediate change in colour. Check-ups were performed 1 and 12 months later. All the defects which were treated showed a degree of attenuation. The teeth affected by molar incisor hypomineralization (MIH) showed partial attenuation in 8 cases, and only in one case the defect disappeared. Regarding the post-trauma cases, 6 were partially attenuated and 2 disappeared. The post orthodontic defects disappeared in 6 cases and were attenuated in 5. All incipient caries defects were completely hidden. Four out of 6 cases of fluorosis disappeared. Diagnosis plays a key role in guiding the dental clinical selection of treatment. While it has always been possible to achieve a high level of attenuation in cases of fluorosis and lesions of caries origin, cases of MIH should probably be treated using more invasive techniques. Post-trauma lesions should be infiltrated with caution, and only after having informed the patient of the possible ineffective outcome.

Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes.

OBJECTIVE: Linear enamel hypoplasia (LEH) is a condition marked by localized reductions in enamel thickness, resulting from growth disruptions during dental development. We use quantitative criteria to characterize the depth of LEH defects and "normal" perikymata in great apes. We test the hypothesis that mountain gorillas have shallow defects compared to other taxa, which may have led to their underestimation in previous studies. MATERIALS AND METHODS: Previous attempts to characterize LEH morphology quantitatively have been limited in sample size and scope. We generated digital elevation models using optical profilometry (Sensofar PLu Neox) and extracted 2D coordinates using ImageJ to quantify depths in canines from three great ape genera (N = 75 perikymata; 255 defects). RESULTS: All defect depths fall outside the distribution of perikymata depths. Mountain gorilla defects are significantly shallower than those of other great ape taxa examined, including western lowland gorillas. Females have significantly deeper defects than males in all taxa. The deepest defect belongs to a wild-captured zoo gorilla. Virunga mountain gorilla specimens collected by Dian Fossey exhibit deeper defects than those collected recently. DISCUSSION: Shallow defect morphology in mountain gorillas may have led to an underestimation of LEH prevalence in past studies. Defect depth is used as a proxy for insult severity, but depth might be influenced by inter- and intra-specific variation in enamel growth. Future studies should test whether severe insults are associated with deeper defects, as might be the case with Haloko, a wild-captured gorilla. Ongoing histologic studies incorporating associated behavioral records will test possible factors that underlie differences in defect morphology.

Molar incisor hypomineralization: proportion and severity in primary public school children in Graz, Austria.

OBJECTIVE: The aim of this study was to determine the proportion and severity of molar incisor hypomineralization (MIH) in primary school children in Graz (southeast of Austria). MATERIALS AND METHODS: In 1111 children aged 6 to 12 years (mean age 9.0 ± 1.2), a wet examination of all teeth was performed by three trained examiners using a dental chair, optimal illumination, a dental mirror, and a dental explorer. All teeth with MIH lesions were registered so that different definitions of MIH were applicable. According to the European Academy of Pediatric Dentistry criteria that were considered valid at the time of the investigation, MIH was diagnosed when at least one first primary molar (FPM) was affected. RESULTS: MIH was present in 78 children (7.0%). In 64 children (5.8%), at least one molar and one incisor were affected (so-called M + IH). Additionally, in 9 children, only incisors were affected. In 7 affected children, teeth other than FPMs and incisors had MIH lesions. Almost an equal number of males (38) and females (40) were affected. The upper and lower molars were equally affected. The upper incisors were more frequently affected than the lower ones. Demarcated enamel opacities were the predominant types of defects. CONCLUSION: The proportion of MIH was 7.0% in Graz, which is similar to other comparable trials. CLINICAL RELEVANCE: This study has proven that MIH is an existing dental problem in Graz.

DLX3 promotes bone marrow mesenchymal stem cell proliferation through H19/miR-675 axis.

The underlying molecular mechanism of the increased bone mass phenotype in Tricho-dento-osseous (TDO) syndrome remains largely unknown. Our previous study has shown that the TDO point mutation c.533A>G, Q178R in DLX3 could increase bone density in a TDO patient and transgenic mice partially through delaying senescence in bone marrow mesenchymal stem cells (BMSCs). In the present study, we provided a new complementary explanation for TDO syndrome: the DLX3 (Q178R) mutation increased BMSCs proliferation through H19/miR-675 axis. We found that BMSCs derived from the TDO patient (TDO-BMSCs) had stronger proliferation ability than controls by clonogenic and CCK-8 assays. Next, experiments of overexpression and knockdown of wild-type DLX3 via lentiviruses in normal BMSCs confirmed the results by showing its negative role in cell proliferation. Through validated high-throughput data, we found that the DLX3 mutation reduced the expression of H19 and its coexpression product miR-675 in BMSCs. Function and rescue assays suggested that DLX3, long noncoding RNA H19, and miR-675 are negative factors in modulation of BMSCs proliferation as well as NOMO1 expression. The original higher proliferation rate and the expression of NOMO1 in TDO-BMSCs were suppressed after H19 restoration. Collectively, it indicates that DLX3 regulates BMSCs proliferation through H19/miR-675 axis. Moreover, the increased expression of NOMO1 and decreased H19/miR-675 expression in DLX3 (Q178R) transgenic mice, accompanying with accrual bone mass and density detected by micro-CT, further confirmed our hypothesis. In summary, we, for the first time, demonstrate that DLX3 mutation interferes with bone formation partially through H19/miR-675/NOMO1 axis in TDO syndrome.

Applying standard perikymata profiles to Pongo pygmaeus canines to estimate perikymata counts between linear enamel hypoplasias.

OBJECTIVES: Recently, studies have interpreted regular spacing and average number of perikymata between dental enamel defects in orangutans to reflect seasonal episodes of physiological stress. To estimate the amount of time between developmental defects (enamel hypoplasia), studies have relied on perikymata counts. Unfortunately, perikymata are frequently not continuously visible between defects, significantly reducing data sets. A method is presented here for estimating the number of perikymata between defects using standard perikymata profiles (SPP) that allow the number of perikymata between all pairs of defects across a tooth to be analyzed. The SPP method should allow the entire complement of defects to be analyzed within the context of an individual's crown formation time. MATERIALS AND METHODS: The average number of perikymata were established per decile and charted to create male and female Pongo pygmaeus SPPs. The position of the beginning of each defect was recorded for lower canines from males (n = 6) and females (n = 17). The number of perikymata between defects estimated by the SPP was compared to the actual count (where perikymata were continuously visible). RESULTS: The number of perikymata between defects estimated by the SPPs was accurate within three perikymata and highly correlated with the actual counts, significantly increasing the number of analyzable defect pairs. CONCLUSION: SPPs allow all defect pairs to be included in studies of defect timing, not just those with continuously visible perikymata. Establishing an individual's entire complement of dental defects makes it possible to calculate the regularity (and potential seasonality) of defects.