Development Of Permanent Teeth Research Articles

Artificial intelligence and dental age estimation: development and validation of an automated stage allocation technique on all mandibular tooth types in panoramic radiographs.

Age estimation in forensic odontology is mainly based on the development of permanent teeth. To register the developmental status of an examined tooth, staging techniques were developed. However, due to inappropriate calibration, uncertainties during stage allocation, and lack of experience, non-uniformity in stage allocation exists between expert observers. As a consequence, related age estimation results are inconsistent. An automated staging technique applicable to all tooth types can overcome this drawback.This study aimed to establish an integrated automated technique to stage the development of all mandibular tooth types and to compare their staging performances.Calibrated observers staged FDI teeth 31, 33, 34, 37 and 38 according to a ten-stage modified Demirjian staging technique. According to a standardised bounding box around each examined tooth, the retrospectively collected panoramic radiographs were cropped using Photoshop CC 2021® software (Adobe®, version 23.0). A gold standard set of 1639 radiographs were selected (n31 = 259, n33 = 282, n34 = 308, n37 = 390, n38 = 400) and input into a convolutional neural network (CNN) trained for optimal staging accuracy. The performance evaluation of the network was conducted in a five-fold cross-validation scheme. In each fold, the entire dataset was split into a training and a test set in a non-overlapping fashion between the folds (i.e., 80% and 20% of the dataset, respectively). Staging performances were calculated per tooth type and overall (accuracy, mean absolute difference, linearly weighted Cohen's Kappa and intra-class correlation coefficient). Overall, these metrics equalled 0.53, 0.71, 0.71, and 0.89, respectively. All staging performance indices were best for 37 and worst for 31. The highest number of misclassified stages were associated to adjacent stages. Most misclassifications were observed in all available stages of 31.Our findings suggest that the developmental status of mandibular molars can be taken into account in an automated approach for age estimation, while taking incisors into account may hinder age estimation.

Application of Slice Culture System for Successional Dental Lamina in Diphyodont Mammals.

Replacement teeth develop from the successional dental lamina (SDL). Understanding how SDL transitions from quiescence to initiation is crucial for preserving dental lamina stem cells in the jawbone microenvironment and for complete tooth regeneration. Miniature pigs are good models for studying human tooth replacement because of their similarities to humans. However, the molecular mechanisms and cellular composition that initiate SDL development remain unclear. One possible reason for this is the limitations of the current methods for culturing SDL in vitro, such as the inability to directly observe tooth morphological changes during culture and low tissue viability. This study aimed to improve the in vitro culture method for SDL. Using a McIlwain Tissue Chopper, we obtained mandibular slices containing deciduous canine and SDL of permanent canine. The slices were approximately 500 μm thick and were cultured on a Transwell membrane supported with metal grids over medium. The SDL developed into the bud stage on the second day and entered the cap stage on the fifth day in vitro. The expression of proliferation markers, cell death markers, and key odontogenetic genes in vitro was similar to that observed invivo. In conclusion, we successfully applied a slice culture system to the SDL of miniature pigs. This slice culture method allowed us to directly visualize SDL initiation and further elucidate the molecular mechanisms underlying the initiation of permanent tooth development.

Interceptive Management of Dilacerated Maxillary Incisor: A Case Report

Because of the intimate physical link between the primary tooth and the permanent tooth germ, traumatic dental injuries in the primary dentition might impair the development of permanent teeth, particularly in the maxillary front region. Dilaceration is a condition that is commonly encountered as a result of dental trauma and is defined as an abrupt deviation along the long axis of the tooth that can be visible between the crown, root, or both. Due to their location within the esthetic zone, such teeth present a special difficulty to the pediatric dentist. This article aims to describe a case of a 09-year-old female patient with an ectopic permanent maxillary central incisor, which was diagnosed as dilacerated after the radiographic examination. The case was managed with an interceptive approach using a Hawley palate.

Accuracy of different dental age assessment methods to determine chronological age among children with special needs.

This study aimed to validate the accuracy of dental age (DA) based on the dental development of permanent teeth in children with special needs using Demirjian, Willems, and London Atlas methods and to correlate the dental and chronological age (CA) of children with special needs in Malaysia. The panoramic radiographic images belonging to children with special needs from the two teaching dental hospitals in Malaysia aged between 5 and 16 years were included in the study. The evaluation was performed by two observers using three methods (London Atlas, Demirjian, and Willems methods) to estimate the accurate DA. The outcome was determined by comparing the mean of the DA and CA. A total of 52 panoramic radiographs were available for the analysis. The London Atlas and Demirjian methods overestimated the DA with a mean of 0.05 and 0.20 years, respectively, while the Willems method underestimated by 0.19 years. The London Atlas method was highly precise and accurate, while Demirjian and Willems methods were the least precise and accurate. The London Atlas method of DA estimation is highly accurate and valid for children with special needs in the Malaysian population, followed by the Willems and Demirjian methods.

Abnormal tooth maturation associated with port wine stains.

This study aims to evaluate the potential impact of port wine stains on the development of permanent teeth in mixed dentition and provide insights for managing tooth abnormalities in patients with port wine stains. A retrospective analysis was conducted on 21 patients with mixed dentition and unilateral maxillary port wine stains. Two researchers concurrently utilized Nolla Analysis to assess the developmental stage of bilateral maxillary and permanent mandibular teeth based on panoramic radiographs. The cumulative developmental values of upper and lower permanent teeth on both sides were calculated, and a comparison was made between the developmental stages of the upper and lower jaws. Port wine stains can influence the maturity of permanent upper teeth, within the unilateral maxillary port wine stains range, with an early developmental completion observed on the affected side compared to the unaffected side. While the developmental stages of the lower teeth on both sides showed similarities. Port wine stains can accelerate the maturity of teeth on the affected side, leading to alterations in the order of tooth eruption and subsequent abnormal occlusion in children with mixed dentition. These findings provide a basis for developing appropriate management strategies for addressing tooth abnormalities in patients with port wine stains.

Enamel developmental defects: environmental factors and clinical management

Enamel formation is a complex physiological process that depends on the coordinated regulation of multiple mechanisms. This process is quite sensitive to various local and systemic interference factors. Therefore, during the long period from the embryonic stage to adolescence or even adulthood, various interference factors may lead to enamel developmental defects. Among them, early life is the most sensitive stage to environmental factors exposure, while it is also the critical period of enamel development of deciduous and permanent teeth. Environmental factors exposure during this period often leads to varying degrees of enamel development defects. In this review, we generalize the research progress of environmental factors affecting enamel developmental defects, summarize the potential mechanisms of environmental factors leading to enamel developmental defects, and conclude the clinical management strategies based on tertiary prevention. This work hopes to provide a theoretical basis for preventing abnormal teeth development from the critical time window of early life, propose eugenics health consultation and promote children 's oral health management.

Iatrogenic Incidents in Primary Molar Pulpectomy: A Case Series Report and Literature Review

Pulpectomy is a common treatment for severe carious lesions in primary molars. Care should be taken during pulpectomy of the primary teeth for successive permanent teeth. This case series report aimed to describe the cases of three patients who experienced excessive extrusion of canal filling materials and file separation during primary molar pulpectomy. The presence of separated files or excessive overfilling materials observed around successive permanent tooth germs leads to underdevelopment and may trigger cystic changes owing to abscess formation. The most important aspect is to preserve the unerupted successive developing permanent tooth. Therefore, clinicians should consider the anatomy of the primary molars prior to endodontic treatment, be careful when manipulating instruments during pulpectomy, provide appropriate treatment if iatrogenic incidents occur during endodontic treatment, and perform close follow-up to ensure the successful development and eruption of subsequent permanent teeth.

Effect of Chronic Apical Periodontitis in Primary Molars on Succedaneous Permanent Teeth: An Observational Retrospective Study.

Periapical infection of primary molars affects the development of permanent teeth (premolars). Therefore, the present study was conducted to test the null hypothesis in children aged 4-10 years with chronic apical periodontitis (CAP) of the primary molars. A retrospective, cross-sectional study was conducted on 185 panoramic radiographs of healthy children aged 4-10 years with CAP in the primary molars. A total of 256 infected primary molars (144 teeth in females, 112 teeth in males) were analyzed, radiographically, and compared with 245 healthy primary molars on the contralateral side. Permanent successors were evaluated for follicular damage, maturation, morphology, and deviation in the eruption path. Primary molars were evaluated for root resorption. Sixteen permanent teeth on the affected side and five teeth on the control side were excluded due to abnormal development. Student's t-test and the chi-square test were used to analyze the data. The null hypothesis is rejected. There were significant differences in the developmental status of permanent successors on the affected side, compared to the normal side at four to seven years (p<0.05). There were no significant sex differences in the abnormalities of permanent successors on the affected side (p>0.05). As the root resorption of the primary molars increased, the follicular damage observed in the permanent successors also increased (p<0.05), which suggests that, as the infection of primary molars increases, more damage is caused to underlying permanent successors (premolars). Apical periodontitis of the primary molars retards the development of permanent successors (premolars), affects their shape, causes follicular damage, and alters the eruption path.

Timing of Permanent Tooth Development in an Iranian Subpopulation

Timing of Permanent Tooth Development in an Iranian Subpopulation

Impacted Deciduous Second Mandibular Molar Tooth

A 9-years-old boy presented to the Department of Oral and Maxillofacial Surgery with pain in the posterior region of the left mandible. The child was healthy with an unremarkable medical history. There was no family history of the same condition. Intra-oral clinical examination showed the absence of lower left deciduous molar and multiple carious deciduous teeth at both dental arches. Orthopantogram (OPG) confirmed the complete impaction of the lower-left deciduous 2nd molar with inferior retention of the lower 2nd permanent premolar close to the lower border of the mandible [Panel A]. Under local anesthesia, a two-sided flap was raised, surgical removal of the impacted deciduous 2nd molar and extraction of adjacent 1st deciduous molar, the flap was sutured with 3/0 silk suture [Panel B and C]. Failure of eruption or impaction of deciduous molar was linked to the disturbance of the development of the successor's permanent teeth. Deciduous tooth failure of eruption or impaction is rare in comparison with permanent teeth. Among deciduous dentitions, the 2nd molar was the most commonly affected tooth, followed by central incisors. Impaction can cause many serious problems to underlying tooth buds of the permanent dentition including their delayed eruption or even ectopic eruption. Therefore, proper history and clinical examination, and precise treatment are mandatory. After one month, OPG showed complete healing [Panel D] and the patient was satisfied with the aesthetic and functional outcomes.

Platelet-rich Fibrin Promotes the Proliferation and Osteo-/odontoblastic Differentiation of Human Dental Pulp Stem Cells.

Pulp regeneration is a promising strategy that promotes the continued development of young permanent teeth with immature apical foramen. Platelet-rich fibrin (PRF) was found to stimulate the proliferation and differentiation of osteoblasts, but its effects on osteoblast/odontoblast differentiation of human dental pulp stem cells (hDPSCs) are unknown. The hDPSCs were isolated and identified using known surface markers by flow cytometry. The CCK-8 assay and the expression of Ki67 and PCNA were used to examine hDPSC proliferation. After 7 days of culture in an osteo-/odontoblastic induction medium with various concentrations of liquid PRF (0, 10% and 20%), the early stage of osteogenesis-intracellular alkaline phosphatase (ALP) was checked. After 21 days of culture, matrix mineralization was checked using Alizarin Red S and quantified. The mRNA and protein levels of osteo-/odontoblastic genes, including RUNX2, DSPP, DMP1 and BSP, were measured by qRT-PCR. The notch signal was checked by Western blot to analyze three key proteins (Notch 1, Jagged 1 and Hes 1). PRF-treated groups showed higher expression of Ki-67 and PCNA, higher ALP activity, and the higher dose showed a stronger induction. PRF promoted osteo-/odontoblastic differentiation of hDPSCs indicated by elevated protein levels and mRNA levels of the expression of osteo-/odontoblastic markers. The three key proteins in Notch signaling showed an increase compared with the control group and increased as the PRF concentration increased. PRF can promote the proliferation and osteo-/odontoblastic differentiation of hDPSC, which may be through the Notch signaling pathway.

Age Assessment through Third Molar Teeth Developmental Stage in Children

Age determination is important for forensic evaluation and for determining criminal responsibility. Based on the development of permanent teeth, the Demirjian staging evaluation key is commonly used in research for estimating age using teeth developmental stage. The purpose of the current study was to correlate the dental developmental age of third molar teeth with the chronological age of adolescent patients. This study evaluated 324 panorex images of Israeli patients aged 8–21 years with known birth dates and genders. The dental developmental stage was compared to the patient’s chronological age by gender and side (right/left and upper/lower jaws). This study also attempted to predict the patient’s age using the third molar developmental stage. The study included 179 male and 145 female patients. There was no statistical difference between the right and left sides of the upper or lower teeth. A strong correlation was found between third molar development and chronological age for both the maxilla and mandible. In 100% of cases, patients in developmental stage &gt;5 were over 12 years old in the maxilla and in 97% of cases, were over 12 years old in the mandible. Patients in developmental stage &gt;6 were over 14 years old in 100% of cases in both the maxilla and mandible. Patients in developmental stage &gt;7 were over 16 years old in 100% of cases in both the maxilla and mandible. This study found that third molars can be used to accurately estimate age in a narrow age range, with a strong correlation between third molar development and chronological age. Further research may be needed to understand the utility of this method and its possible usage in different countries around the world.

The effects of 4-Phenylbutyric acid on ER stress during mouse tooth development.

Introduction: During tooth development, proper protein folding and trafficking are significant processes as newly synthesized proteins proceed to form designated tissues. Endoplasmic reticulum (ER) stress occurs inevitably in tooth development as unfolded and misfolded proteins accumulate in ER. 4-Phenylbutyric acid (4PBA) is a FDA approved drug and known as a chemical chaperone which alleviates the ER stress. Recently, several studies showed that 4PBA performs therapeutic effects in some genetic diseases due to misfolding of proteins, metabolic related-diseases and apoptosis due to ER stress. However, the roles of 4PBA during odontogenesis are not elucidated. This study revealed the effects of 4PBA during molar development in mice. Methods: We employed in vitro organ cultivation and renal transplantation methods which would mimic the permanent tooth development in an infant period of human. The in vitro cultivated tooth germs and renal calcified teeth were examined by histology and immunohistochemical analysis. Results and Discussion: Our results revealed that treatment of 4PBA altered expression patterns of enamel knot related signaling molecules, and consequently affected cellular secretion and patterned formation of dental hard tissues including dentin and enamel during tooth morphogenesis. The alteration of ER stress by 4PBA treatment during organogenesis would suggest that proper ER stress is important for pattern formation during tooth development and morphogenesis, and 4PBA as a chemical chaperone would be one of the candidate molecules for dental and hard tissue regeneration.

Assessment of permanent teeth development in children with multiple persistent primary teeth.

Persistent primary teeth (PPT) may occur due to various local factors, or it may develop due to general factors such as systemic diseases and syndromes. Since eruption and dental development are two different processes, it is important to investigate both processes to determine the actual cause of delayed tooth eruption. The study aimed to evaluate the dental development of a group of Turkish children with multiple PPT using the Willems dental age estimation method. Digital panoramic radiographs of children and adolescents aged between 9 and 15 years were retrieved, assessed and categorized. A total of 80 radiographs of patients with more than one PPT were selected and matched with children without PPT. Dental age was calculated using the method of Willems et al. All analyses were conducted using the SPSS statistical software. The statistical significance was set at 0.05. The permanent tooth development of children with multiple PPT could be delayed by 0.5-4 years compared to healthy ones. A strong positive correlation was found between the number of PPT and deviation for both females and males (p < 0.001). In conclusion, we found that permanent tooth development of children with multiple PPT could be delayed compared to healthy ones. In addition, as the number of PPT increased, the difference between chronological age and dental age also increased, especially in males.

Clinical condition of teeth and dentition in children and adolescents with cerebral palsy

BACKGROUND: Literature and statistical data reveal the increasing incidence of psychoneurological diseases (PND) and thus dental pathologies with PND in children and adolescents. Thus, the authors examined the structures and frequency of dental defects and deformities in patients with PND. Children and adolescents with PND aged 718 years are at high risk for the development of dental pathologies, and oxidative stress and immune system disorder present major associations with the pathogenesis of dental pathologies.&#x0D; AIM: To determine the structure and frequency of dental defects and deformities in children and adolescents with PND and study the etiopathogenetic factors and mechanism of pathology formation to guide the development of preventive measures.&#x0D; MATERIAL AND METHODS: The study comprehensively analyzed the data of 299 patients aged 718 years, of which 143 were diagnosed with PND based on the International Classification of Disease 10th Revision (main group; МG) and 156 somatically healthy patients with dental pathologies (control group; CG). The participants were divided into two subgroups: 75 patients aged 712 years (52.44%; МG-1) and 68 patients aged 1318 years (47.55%; МG-2) from the main group (MG) and 65 (41.66%; CG-1) and 91 (58.33%; CG-2) patients from the CG of the respective age groups.&#x0D; RESULTS: The incidence rates of caries in the temporary teeth of MG-1 and CG-1 were 97.33% and 84.61% and in the permanent teeth of MG-2 and CG-2 were 95.58 and 87.91%, respectively. In the pre-eruptive period, the rates of dental lesions were as follows: hypoplasia, 20.97%; impaired dentition, 49.65%; primary adentia, 47.55%; anomalies of the completeness of teeth, 64.33%; endemic fluorosis of teeth, 2.79% in patients with PND; and 12.17%, 12.17%, 26.92%, 11.53%, and 0.6% in children and adolescents in CG, respectively (p 0.0001): disappearance of dental hard tissues, 9.09%; dental injuries, 24.47%; enamel necrosis, 7.7%; enamel erosion, 17.5% of patients with MG. In children and adolescents of CG, only tooth trauma was noted in 7.7% and enamel necrosis in 1.3%. In patients with PND, 49.6% had distal occlusion; 37.8%, cross occlusion; 31.6%, neutral occlusion; 29.9%, deep incisor occlusion; 25.9%, deep incisor malocclusion; 54.5%, narrowing of the lower dentition; 43.3%, crowding of teeth in the lower jaw; 26.6%, diastemas; and tremas, 23.8%.&#x0D; CONCLUSION: Non-carious lesions of the teeth and a shift in the timing of the development of temporary and permanent teeth are more common in MG than in CG and lead to impaired dental anatomy and disrupt the aesthetics of smiles, speech, etc. Moreover, hypertrophic gingivitis and local periodontitis were characteristic of children with severe PND, who are at high risk for dental pathologies associated with oxidative stress and genetically related immune system disorders, especially in older children with PND.

Are platelet concentrate scaffolds superior to traditional blood clot scaffolds in regeneration therapy of necrotic immature permanent teeth? A systematic review and meta-analysis.

The effectiveness of platelet concentrates in promoting root development of necrotic immature permanent teeth is unclear. The present study evaluated whether the platelet concentrate protocol was superior to the traditional blood clot protocol in regeneration therapy. We searched Electronic databases, such as PubMed, Cochrane Library, ClinicalTrials and EMBASE. Randomized controlled trial studies, cohort studies, case-control studies and cross-sectional studies were included, in which platelet-rich concentrates were tested for periapical healing and root development, with the blood clot treatment protocol as the control group. Clinical and radiographic outcomes were considered. Selected articles were assessed for risk of bias. Pooled risk ratios (risk ratio, RR) were calculated for clinical success, responses to cold and electric pulp tests, periapical lesions, apex closure, root lengthening, and thickening of the dentin walls. Subgroup meta-analysis were conducted according to the type of platelet concentrate used. Of the 1272 screenedstudies, 13 randomized controlled studies, 2 case-control studies and 1 cohort study were selected, in which 465 immature necrotic permanent teeth, particularly incisors and premolars, were treated. Of these 465 teeth, 457 (98.2%) in both the control and experimental groups remained clinically asymptomatic for the entire study duration, whereas eight (1.8%) showed signs and symptoms of failure, including spontaneous pain, sensitivity to percussion or reinfection. Compared with control teeth, teeth treated with PRP achieved better apical healing than BC group (RR 1.13, 95% CI 1.01-1.26, P = 0.03), and teeth treated with platelet concentrates showed improved apical closure (RR 1.04, 95% CI 0.86-1.25, P = 0.69), root lengthening (RR 1.01, 95% CI 0.74-1.39, P = 0.93), and thickening of the dentin walls (RR 1.35, 95% CI 0.95-1.93, P = 0.09), although these differences were not statistically significant. Platelet concentrates can be used as successful scaffolds for regenerative endodontic treatment of necrotic immature permanent teeth, and PRP as a scaffold may achieve better periapical healing of teeth with periapical inflammation, although they did not differ significantly from conventional blood clot scaffolds in development of the root.

Subadult Age Estimation Using the Mixed Cumulative Probit and a Contemporary United States Population

The mixed cumulative probit (MCP), a new, flexible algorithm that accommodates a variety of mean and shape parameters in univariate models and conditional dependence/independence in multivariate models, was used to develop subadult age estimation models. Sixty-two variables were collected on computed tomography (CT) images of 1317 individuals (537 females and 780 males) aged between birth and 21 years from the United States sample in the Subadult Virtual Anthropology Database (SVAD). Long bone measurements (n = 18), stages of epiphyseal fusion and ossification (n = 28), and stages of dental development of permanent teeth (n = 16) were used in univariate, multivariate, and mixed models and compared using test mean log posterior (TMNLP), root mean squared error (RMSE), and percent accuracy on an independent test sample. Out of the six possible parameter combinations, all combinations were accounted for at least once in the data and conditionally dependent models outperformed the conditionally independent models. Overall, multivariate models exhibited smaller TMNLP and RMSE, and an overall greater stability in the age estimations compared to univariate models across all ages and independent of indicator type. Pre-optimized subadult age estimation models are freely available for immediate application through MCP-S-Age, a graphical user interface.

Strategies to Improve Dental Hygiene and Oral Health of 5-15-year-old Students: A Systematic Review

School is the most cost-effective and easiest way to access 5-15-year-old children. Owing to the development of permanent teeth, the increasing prevalence of dental caries, and the formation of social life, these children are the main target group in oral hygiene promotion programs. The present study aimed to evaluate the effect of interventional strategies on improving oral health and dental hygiene of 5-15-year-old students. Electronic search in Scopus, PubMed, Science Direct, Springer, and Biomed Central databases was performed using English keywords, and the studies that were conducted on educational interventions to improve oral health, dental hygiene, prevention, and control of caries among students between January 2004 and March 2021 were reviewed. Thirteen selected studies were divided into two categories: educational interventions based on self-care behaviors and prevention services (fluoride varnish and fissure sealant) and educational interventions based on self-care behaviors. Interventions that included continuing the intervention, involved parents and school staff in the program, used a combination of several educational methods and used preventive services were associated with greater success in enhancing knowledge, health behaviors, reducing plaque, and tooth decay. Continuation of group education, combined use of educational programs, follow-up, and the use of behavior change models and provision of preventive services are the best ways to design and plan an intervention to improve oral health and dental hygiene in elementary school students.

How to Make a Vampire: Part II. Getting Ready to Feed

The mammalian feeding system is made up of multiple components that influence facial variation, including the masticatory muscles, bony jaw apparatus, and teeth. However, it is not fully understood how the development of these components are coordinated and are impacted by life history and diet.Bats are the only mammals that continue to nurse until they are almost adult size, and often after they become volant. Common vampire bats (Desmodus rotundus) have a relatively prolonged juvenile period among bats, can nurse up to nine months, and later solely subsist off of blood. Feeding system maturity may therefore be delayed in bats, and particularly delayed in Desmodus, as a result of their lengthy juvenile period and liquid diet. In this study, we examine the developmental maturity of the cranium and feeding apparatus in the late fetus of a common vampire bat (Desmodus rotundus) relative to an adult (its mother).The heads of each specimen were microCT scanned twice. Conventional microCT was used to image mineralized tissues. Diffusible iodine‐based contrast‐enhanced CT (diceCT) imaging was used to image soft tissues. Cranial length and palate length measurements were acquired from unstained scans to evaluate size and jaw apparatus development. Masticatory muscles (e.g., medial pterygoid, zygomaticomandibularis) and permanent tooth crypt volumes were acquired from stained tissue scans to evaluate masticatory muscle and tooth development. Developmental maturity of these structures was assessed by calculating a percentage of the growth completed (i.e., [fetal muscle volume/adult muscle volume]*100).In the fetus, permanent tooth crypt volume is already comparable to the adult condition despite cranial length and palate length being &lt;75% of adult size. Masticatory muscle volume maturity is highest in the lateral pterygoid muscle (~35%), whereas other masticatory muscles are far less developed (e.g., medial pterygoid volume maturity, ~20%; temporalis profundus volume maturity, ~20%; temporalis medius volume maturity, ~6%).These results reveal highly precocious permanent tooth development in Desmodus. Although this may facilitate transition to hematophagy, Desmodus do not fly until eight to ten weeks, so the precocious incisors may primarily aid the infant to grip its mother’s skin. Differential development of the masticatory muscles may also be influenced by the need for young bats to use their mouths to help anchor themselves to their mother early in life. This may explain the advanced maturity of the lateral pterygoid muscle, which would protrude the jaw and help to facilitate a more secure grip.

In Vivo Evaluation of Decellularized Human Tooth Scaffold for Dental Tissue Regeneration.

Conventional root canal treatment may result in loss of tooth vitality, which can lead to unfavorable treatment outcomes. Notably, a ceased tooth development of immature permanent teeth with open apices, regeneration of periodontal ligaments (PDL), and pulp is highly expected healing process. For regeneration, the scaffold is one of the critical components that carry biological benefits. Therefore, this study evaluated a decellularized human tooth as a scaffold for the PDL and pulp tissue regeneration. A tooth scaffold was fabricated using an effective decellularization method as reported in previous studies. PDL stem cells (PDLSCs) and dental pulp stem cells (DPSCs) obtained from human permanent teeth were inoculated onto decellularized scaffolds, then cultured to transplant into immunosuppressed mouse. After 9 weeks, PDLSCs and DPSCs that were inoculated onto decellularized tooth scaffolds and cultured in an in vivo demonstrated successful differentiation. In PDLSCs, a regeneration of the cementum/PDL complex could be expected. In DPSCs, the expression of genes related to revascularization and the hard tissue regeneration showed the possibility of pulp regeneration. This study suggested that the potential possible application of decellularized human tooth could be a scaffold in regeneration PDL and pulp tissue along with PDLSCs and DPSCs, respectively, as a novel treatment method.