Early Tooth Research Articles

Root Crack Identification of Sun Gear in Planetary Gear System Combining Fault Dynamics with VMD Algorithm

Planetary gearbox is widely used in various low-speed machines due to its large transmission ratio. However, the gears in a planetary gearbox are prone to the mechanical faults due to the complex dynamic heavy load. Vibration frequencies caused by an early tooth root crack of sun gear are usually difficult to accurately extract, so its fault diagnosis is one of the main challenges of planetary gearbox reliability. In this paper, a simplified tooth root crack model of sun gear is proposed, and then a rigid-flexible coupled dynamics model of the whole planetary gear system is constructed. By the numerical simulation, the fault frequencies caused by a tooth root crack of sun gear are obtained. A Variational Mode Decomposition (VMD) algorithm for the vibration frequency extraction is proposed. The measured vibration signals are decomposed into the sparse Intrinsic Mode Functions (IMFs) by the VMD, and then the IMFs are further analyzed by the spectral method to accurately extract the crack-induced frequency components. The experimental results show that the proposed dynamics model and VMD method are feasible; an error between the characteristic frequencies from the tested signal analysis and the theoretical calculation is less than 1%.

Use of Byproduct Feeds in Southeastern Beef Production Systems

Abstract Byproducts are an important component of many beef production systems in the southeast. A variety of byproducts are used as supplemental nutrition for pastured cattle, and a byproduct-based total mixed ration is commonly used in backgrounding enterprises. Byproducts of corn (wet and dry milling), soybean, cotton, peanuts, rice, citrus, brewing and vegetable processing are widely available. Regional availability will determine what optimal byproducts will be for a given area. The value of an alternative feed for beef cattle is commonly determined based on the TDN and CP levels relative to corn and soybean meal (the Peterson Method). This simple approach allows the user to calculate a $ per ton value at a given corn and soybean meal price, but may result in misleading information. Research comparing alternative feeds to the standard often find that a “realized value” is different than the calculated value. Intake may be stimulated or depressed by a given ingredient. Hidden costs including handling and shrinkage are often a problem for wet materials. Sometimes dramatic side effects occur despite a high calculated value for the feed. For example, fermented sweet potato cannery waste has a very high nutritive value that is realized when fed at low levels in a total mixed ration. However, when fed free-choice, it may cause severe dental erosion resulting in reduced gains in yearlings and early tooth loss in cows. Culled cured sweet potatoes coming from cold storage have a high calculated value yet can cause death in cows because of a lung toxin. There is actually a limited amount of research published with byproducts in southern beef production systems. Due to diversity of forage-base and wide variety of ingredients with potential associative effects, more research is needed to fully understand how byproducts are best utilized.

The Role of CSF1R in Early Tooth Development

Colony stimulating factor 1 receptor (CSF1R) binds its cognate ligand, CSF1, to regulate the survival, proliferation, and differentiation of mononuclear phagocytic cells (e.g. macrophages and monocytes) and osteoclasts, the bone-resorbing cells. Studies on CSF1 and CSF1R have mainly focused on their roles in tissue-resident macrophage homeostasis, immunology, and bone biology. Here we highlight the role of CSF1R in odontogenesis (tooth development) using the mouse model. Odontogenesis occurs via epithelial and mesenchymal interactions controlled by molecular regulatory networks, ultimately resulting in the formation of specialized mineralized tissues by highly differentiated cells. During prenatal stages, mammalian teeth begin development and undergo morphogenesis, cytodifferentiation, and matrix secretion resulting in precise tooth crown shapes and early formation of enamel, dentin, and dental pulp. The formation of cementum and root elongation then follow during early postnatal stages. At later postnatal stages alveolar bone is resorbed by osteoclasts to allow teeth to erupt into the oral cavity and acquire final functions and forms. Mice completely deficient in CSF1 (Csf1op/op) or CSF1R (Csf1r-/-) fail to erupt teeth as a result of defective osteoclast formation. However, dental abnormalities associated with tooth eruption failure have also been observed in these mice postnatally. The overall objective of this study was to explain the role of CSF1R in early odontogenesis and to determine whether CSF1R has a more direct role in odontogenesis independent of that in osteoclast-mediated tooth eruption. We hypothesized that CSF1R regulates morphogenesis, cytodifferentiation, and matrix secretion during early odontogenesis. Using immunohistochemistry, we first showed the localization of CSF1R and CSF1 to be in mesenchymal tissues directly around developing teeth at early time points, and not within differentiated ameloblasts and odontoblasts. To study the impacts on developing teeth, we treated pregnant dams with the CSF1R inhibitor PLX5622 between embryonic day 3.5 (E3.5) and E18. CSF1R inhibition in mice in utero resulted in significant tooth abnormalities observed at postnatal day 21 (P21) and P28, assessed histologically and with high-resolution micro-computed tomography imaging. Importantly, irregular dental tissue infoldings and altered remodeling of bone around developing teeth were observed at prenatal time points. Notably, CSF1R inhibition in P28 mice did not impact enamel and dentin formation in the continuously growing incisors, suggesting that CSF1R does not impact dental stem cells. Together these results indicate that CSF1R regulates tooth morphology early during embryogenesis, by appropriately remodeling bony crypts forming around teeth. Identifying and studying such novel gene regulatory networks involved in the shaping and structuring of teeth will elucidate the wide morphological variations present in various dental anomalies, while also enabling advances in tooth bioengineering.

Pseudogenized Amelogenin Reveals Early Tooth Loss in True Toads (Anura: Bufonidae).

Extant anurans (frogs and toads) exhibit reduced dentition, ranging from a lack of mandibular teeth to complete edentulation, as observed in the true toads of the family Bufonidae. The evolutionary time line of these reductions remains vague due to a poor fossil record. Previous studies have demonstrated an association between the lack of teeth in edentulous vertebrates and the pseudogenization of the major tooth enamel gene amelogenin (AMEL) through accumulation of deleterious mutations and the disruption of its coding sequence. In this study, we have harnessed the pseudogenization of AMEL as a molecular dating tool to correlate loss of dentition with genomic mutation patterns during the rise of the family Bufonidae. Specifically, we have utilized AMEL pseudogenes in three members of the family as a tool to estimate the putative date of edentulation in true toads. Comparison of AMEL sequences from Rhinella marina, Bufo gargarizans and Bufo bufo, with nine extant, dentulous frogs, revealed mutations confirming AMEL inactivation in Bufonidae. AMEL pseudogenes in modern bufonids also exhibited remarkably high 86-93% sequence identity among each other, with only a slight increase in substitution rate and relaxation of selective pressure, in comparison with functional copies in other anurans. Moreover, using selection intensity estimates and synonymous substitution rates, analysis of functional and pseudogenized AMEL resulted in an estimated inactivation window of 46-60 million years ago in the lineage leading to modern true toads, a time line that coincides with the rise of the family Bufonidae.

Morphological features of bone tissue in "disuse atrophy" on the example of a segment of the human lower jaw: clinical experience of treatment

Current real-time science and technology techniques based on ENDORET PRGF technologies and the implementation of their results in practical medicine, provide ample opportunities for the use of cell autotransplantation for guided tissue regeneration, including in the treatment of "disuse atrophy" of the human lower jaw bone tissue with early tooth loss. The purpose of this work is to ensure the principles of biological feasibility and physiological capacity, technical rationality. The pathology in the distal segment of a lower limb, which is a vertical atrophy of bone tissue was confirmed by the methods of computed tomography, Vatech PaX-I 3D Green systems of extra-oral radiography with a scan size range of 16×9 cm, a focal spot of 0.5 mm (IEC60336) with a gray scale of 14 bits with a size of 0.2/0.3 voxel. Using ENDORET PRGF technology, according to the approved BTI protocol, autocellular grafts that have provided a positive result that meets the basic principles of the goal in restoring the mechanisms of physiological processes of normal quantitative and qualitative morphology of bone tissue, with its biological characteristics were obtained. The results of the study showed that bone tissue on a scale of shades of gray based on the classification of Hounsfield, is not characterized by a single biotype and in the area of missing 3.6 tooth belongs to the second biotype, and in the area of missing 3.7 tooth – to the first biotype by its density. The indicators of densitometric determination confirmed excessive mineralization of the trabecular layer, ie vertical atrophy of bone tissue, which is in the sagittal section in the projection of the missing 36 teeth – with a maximum number of 881 gray standard units (GSU), M=315 GSU (where, M is the average value of absolute number); sagittal section in the projection of the missing 37 teeth – with a maximum number of 1726 GSU, M=1173 GSU. This clinical experience with the use of autocellular grafts in the treatment of "disuse atrophy" of the bone tissue of the jaws, which is essentially scientifically-research in nature, based on modern, at the same time available technologies of cell engineering and technical progress, provides a predictable result of clinical observation and deserves further research and practical testing.

Manutenção de espaço: da etiologia à interceptação

INTRODUÇÃO: A manutenção do espaço, quando ocorre perda precoce de dentes decíduos, impede que um problema em potencial - a migração dentária - determine a formação de uma maloclusão, constituindo uma manobra ortodôntica preventiva. A perda de um dente decíduo é considerada precoce quando este é perdido antes que seu sucessor permanente tenha iniciado o processo de irrupção. OBJETIVO: este artigo se propõe a fazer uma revisão da literatura a respeito da perda precoce de dentes decíduos, dando ênfase à sua etiologia, às suas consequências sobre o desenvolvimento do sistema estomatognático e, ainda, aos aparelhos indicados para evitar que se estabeleçam maloclusões dentárias. MATERIAIS E MÉTODOS: a busca dos artigos referenciados foi realizada na base de dados do PubMed e do Google Acadêmico. Aparelhos laboratoriais foram confeccionados em modelos de gesso a fim de demonstrar as possibilidades e indicações de aparelhos fixos ou removíveis, para diferentes situações envolvendo perdas dentárias precoces. CONCLUSÃO: prevenir e interceptar problemas incipientes é muito mais fácil do que corrigi-los no futuro.

Overdenture: An alternative treatment for oral rehabilitation in patients with early childhood caries

Oral rehabilitation in child is an odontopediatric challenge once the restorative treatament needs to be done in quick procedures and few visits for maintain cooperative child behaviour. With these objectives in mind, the present report describes an oral rehabilitation using fixed prosthesis (overdenture) in a 3-year-old boy who had early childhood caries and whose dental roots had been endodontically treated. The use of this device is a good aesthetic and functional solution for early teeth lost. Thus, this treatment approach allowed a harmonic dental maintenance in relation to other structures of the stomatognathic system, thus supporting the maxillary development and guiding the eruption of the permanent teeth, in addition to increasing patient and family satisfaction.

70759 Jaw-specific control of Msx1-dependent odontogenesis by Dkk2 and Sostdc1

ABSTRACT IMPACT: Our proposed jaw-specific control mechanism of tooth development is expected to address the site-specific prevalence of tooth agenesis in humans. OBJECTIVES/GOALS: To determine the molecular mechanisms that control jaw-specific tooth development. To identify the molecular basis of the site-specific prevalence of humans tooth agenesis cases. METHODS/STUDY POPULATION: We used three different genetically engineered mouse lines: Msx1 ^’/ ^’, Dkk2 ^’/ ^’, and Sostdc1 ^’/ ^’ mice. We used developmental mouse genetics approaches, basically generating different combinations of compound mutant mice. We examined their tooth development by using gross, histology, and mRNA expression analyses. RESULTS/ANTICIPATED RESULTS: We identified that Sostdc1, a secreted Wnt inhibitor, also plays an important role in regulating the Msx1-dependent odontogenic pathway. Sostdc1 mRNA showed similar expression patterns in the developing tooth germs between control and Msx1-null molar buds. Remarkably, by deleting the Sostdc1 gene, as well as the Dkk2 gene, in the Msx1-null background mouse, molar tooth development was rescued in the maxillary jaw, but not in the mandibular jaw. Furthermore, tooth developmental rescue could be achieved in both the maxillary and mandibular molars by combinedly deleting Dkk2 and Sostdc1 in Msx1-null mice. DISCUSSION/SIGNIFICANCE OF FINDINGS: Our study demonstrates that secreted Wnt inhibitors Dkk2 and Sostdc1 synergistically regulate the Msx1-dependent odontogenic pathway and further control early tooth morphogenesis. These mouse model will be used to further address the site-specific prevalence of tooth agenesis in humans.

Factors associated with dental fluorosis among Malaysian children exposed to different fluoride concentrations in the public water supply.

To determine the prevalence of dental fluorosis, and factors associated with its occurrence in two cohorts of children exposed to different fluoride concentrations in the Malaysian water supply. A cross-sectional study was conducted among lifelong residents (n=1,155) aged 9 and 12 years old living in fluoridated and nonfluoridated areas. Malaysian children aged 12 years were born when the level of fluoride in the public water supply was 0.7ppm while those aged 9 years were born after the level was reduced to 0.5ppm. Fluorosis was blind scored using standardized photographs of maxillary central incisors using Dean's criteria. Fluoride exposures and other factors were assessed by parental questionnaire. Data were analyzed using descriptive statistics, Chi-squared analyses, and logistic regression. Fluorosis prevalence was lower (31.9percent) among the younger children born after the reduction of fluoride concentration in the water, compared to a prevalence of 38.4percent in the older cohort. Early tooth brushing practices and fluoridated toothpaste were not statistically associated with fluorosis status. However, the prevalence of fluorosis was significantly associated with parents' education level, parents' income, fluoridated water, type of infant feeding method, age breast feeding ceased, use of formula milk, duration of formula milk intake, and type of water used to reconstitute formula milk via simple logistic regression. Fluoridated water remained a significant risk factor for fluorosis in multiple logistic regression. Fluorosis was lower among children born after the adjustment of fluoride concentration in the water. Fluoridated water remained as a strong risk factor for fluorosis after downward adjustment of its fluoride concentration.

Materiales de obturación radicular utilizados en dientes deciduos

La caries y traumatismos son las principales causas de urgencias en odontología pediátrica. Estas afecciones pueden llegar a ejercer un daño irreversible en el tejido pulpar comprometiendo la permanencia de los órganos dentarios afectados. Para limitar el daño pulpar y evitar la extracción de piezas temporales se han diseñado distintas técnicas que van desde recubrimientos pulpares hasta un tratamiento más radical como la pulpectomía. Ésta última consiste en la extirpación del tejido pulpar, la limpieza y desinfección del sistema de conductos y la obturación de los mismos. Diversos autores han descrito las características ideales que debe presentar un material obturador de conductos de la dentición temporal, en los que se incluyen actividad bactericida y bacteriostática, adecuado sellado tridimensional, biocompatibilidad y reabsorción del material a una velocidad similar que las raíces. Desde hace largo tiempo se han desarrollado diversos materiales para cumplir con las exigencias que demanda la técnica. Dentro de los primeros materiales surgidos con éste propósito se encuentran el Óxido de Zinc con Eugenol, Hidróxido de Calcio y materiales a base de yodoformo, con el tiempo surgieron combinaciones de estos materiales para aumentar las ventajas y disminuir las desventajas. De éstos, las pastas yodoformadas con Hidróxido de Calcio son los que han tenido mayor aceptación.

Early Tooth Loss after Periodontal Diagnosis: Development and Validation of a Clinical Decision Model.

The aim of this study was to develop and validate a predictive early tooth loss multivariable model for periodontitis patients before periodontal treatment. A total of 544 patients seeking periodontal care at the university dental hospital were enrolled in the study. Teeth extracted after periodontal diagnosis and due to periodontal reasons were recorded. Clinical and sociodemographic variables were analyzed, considering the risk of short-term tooth loss. This study followed the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) guidelines for development and validation, with two cohorts considered as follows: 455 patients in the development phase and 99 in the validation phase. As a result, it was possible to compute a predictive model based on tooth type and clinical attachment loss. The model explained 25.3% of the total variability and correctly ranked 98.9% of the cases. The final reduced model area under the curve (AUC) was 0.809 (95% confidence interval (95% CI): 0.629–0.989) for the validation sample and 0.920 (95% CI: 0.891–0.950) for the development cohort. The established model presented adequate prediction potential of early tooth loss due to periodontitis. This model may have clinical and epidemiologic relevance towards the prediction of tooth loss burden.

A novel P3H1 mutation is associated with osteogenesis imperfecta type VIII and dental anomalies

Our objective was to investigate the molecular etiology of osteogenesis imperfecta type VIII and dental anomalies in 4 siblings of a Karen tribe family. Four patients and their unaffected parents were studied by clinical and radiographic examination. In situ hybridization of P3h1 during early murine tooth development, whole-exome sequencing, and Sanger direct sequencing were performed. A novel homozygous missense P3H1 mutation (NM_001243246.1; c.2141A>G; NP_001230175.1; p.Lys714Arg) was identified in all patients. Their unaffected parents were heterozygous for the mutation. The mutation is hypothesized to belong to isoform c of P3H1. Mutations in P3H1 are associated with autosomal recessive osteogenesis imperfecta type VIII. Hypodontia, a mesiodens, and single-rooted permanent second molars found in our patients have never been reported in patients with P3H1 mutations. Single-rooted second permanent molars or failure to form multiple roots implies effects of the P3H1 mutation on root development. We report a novel P3H1 mutation as the underlying cause of osteogenesis imperfecta type VIII with dental anomalies. Our study suggests that isoform c of P3H1 is also a functional isoform of P3H1. We report, for the first time, to our knowledge, the association of P3H1 mutation and osteogenesis imperfecta type VIII with dental anomalies.

Vibration Feature Evaluation of the Motor-Gear System with Gear Tooth Crack and Rotor Bar Error

The high speed and high power density electromechanical system for the electric vehicle is urgently required to meet stricter emission regulation and achieve higher performance. Therefore, the electromechanical coupling effect is becoming more strengthened and may significantly degrade the performance of the motor and gear system. When gear or motor failures like gear tooth crack or rotor bar breakage are present, the operation safety of the electric vehicle would be threatened. So the exploration of the fault features for the motor-gear system is crucial for prevention of disastrous consequences. In this paper, the fault vibration features of the motor-gear system with gear root crack and motor rotor error under various excitations from both motor and gear transmission system are investigated. The electromechanical dynamic model considering the nonlinear air-gap permeance and time-varying mesh stiffness is employed, and the gear tooth root crack fault and the rotor bar breakage are integrated into the dynamic model to acquire the dynamic characteristics with faults. Then, the angular-synchronous average technique is applied to strengthen the statistical characteristics of fault vibration signal and eliminate the effect of speed variation due to the external excitation. The statistical indicators extracted from the angular-synchronous average vibration signals can reveal the progression of gear faults for the gear transmission without motor rotor error. However, the analyzed results indicate that the popular statistical indicators would fail to detect the early tooth fault when the motor rotor error is coupled.

Early Pleistocene hominin teeth from Meipu, southern China

The rarity and poor preservation of hominin fossils from the East Asian Early Pleistocene hamper our understanding of their taxonomy and possible phylogenetic relationship with other members of the genus Homo. In the 1970s, four isolated hominin teeth were recovered from the Meipu site, southern China, which biostratigraphic analysis placed in the late Early Pleistocene. Early reports assigned the teeth to late Homo erectus. Since then, the teeth have not been re-evaluated, nor has reliable dating been performed at the Meipu site. Here, biostratigraphic and paleomagnetic dating allow for a more precise chronological constraint of the Meipu hominins in the late Early Pleistocene, between 780 ka and 990 ka, making them one of the few known hominins for this time in mainland Asia. The comparison of the morphology of the Meipu teeth with other members of the genus Homo reveals that the Meipu teeth preserve traits such as moderate shoveling of the I1, the square crown contour of M1, and a buccolingually wider lingual cusp in P4 that make them closer to early Homo specimens from Africa and Homo ergaster from Dmanisi (Georgia). In addition, the Meipu teeth exhibit features that are more typical for late mainland East Asian H. erectus, such as the moderately convex I1 labial surface and a pronouncedly convex I2 labial surface. In these features, the Meipu hominins are morphologically intermediate between African/Dmanisi early Homo and East Asian Middle Pleistocene hominins. This study contributes to a better understanding of the morphologies and the taxonomic status of East Asian Early Pleistocene hominins, a time period for which the hominin evidence with secure stratigraphic context is scarce.

Ellis-Van Creveld Syndrome, neonatal teeth and breastfeeding impairment: a case report

ABSTRACT Because of multisystemic impairment in patients with Ellis-van Creveld syndrome, multidisciplinary care may be demanded since birth to assure breastfeeding. This report presents a case of an Ellis-van Creveld infant that was facing breastfeeding difficulties because of maxillary neonatal teeth. A 3 months old male infant with Ellis-van Creveld syndrome was referred to Pediatric Dentistry Department because of two upper neonatal teeth causing breastfeeding difficulties. Clinical examination revealed that teeth position was compatible to 51 and 61, and both presented uncommon ectopic soft tissue placement, conical crown and hypoplastic enamel covered by a large amount of dental biofilm. Radiography indicated they were of normal series and had 2/3 of crown completion. Due to teeth mobility that impaired breastfeeding, treatment option was exodontia. Early tooth eruption, such as in natal and neonatal teeth, by itself can’t be considered a reason for exodontia. But exodontia must be considered when an early erupted tooth(s) impairs breastfeeding, especially in systemically compromised infants. In this present case report, after teeth extraction, the infant was able to breastfeed and gain weight properly.

Kinetic creativity

ABSTRACT Beginning with a detailed example of ravens accessing food not immediately accessible, this article documents the fact that tool-making and tool-using are a creative kinetic process that engages mindful bodies in the course of their animate lives. It shows how thinking in movement and kinesthetic memory are basic aspects of synergies of meaningful movement in tool-making and tool-using and how corporeal and topological concepts link early hominid stone tools and teeth, concepts such as hardness and edges. The import of if/then relationships becomes evident in a processual awareness of consequential relationships between movement and effect: if I do this, then this happens. Two notable research studies of tool-making are considered, one concerned with identifying areas of the brain involved in tool-making, one concerned with identifying areas of the brain involved in experienced animate realities. Sperry’s conclusions drawn from his research studies of the brain and Kelso’s extension of Sperry’s conclusions in his neurobiological research studies of coordination dynamics support the latter approach. Both sustain the central import of self-movement and the awareness of movement in the process of tool-making and tool-using.

Novel management of Riga-Fede disease associated with early infancy tooth in 4-month-old infant

Novel management of Riga-Fede disease associated with early infancy tooth in 4-month-old infant

The Spatiotemporal Expression Patterns of Mechanical-Stress Related Regulatory Proteins in Mouse Molar Development

In order to better understand the role of mechanical stress in early tooth development, we examined the spatiotemporal expression patterns of mechanical-stress related regulatory protein (actin filament, or F-actin), non-muscle myosin ⅡB (NMⅡB) and vinculin at different stages of tooth development in mice. Mouse first mandible molars were used as the research model. Immunofluorescence staining was performed to detect the expression patterns of F-actin, NMⅡB and Vinculin, the key molecules constituting the chemical mechanical system, at bud, cap, early bell and late bell stages of tooth. F-actin, NMⅡB and vinculin were all expressed in the tooth epithelium in an extensive or a limited way at different stages of tooth development, while F-actin was also expressed steadily in the mesenchymal cells. The quantitative analysis of fluorescence intensity showed that F-actin and NMⅡB exhibited significantly increase in the early stage of tooth development, but then dropped to their basal levels at the end of the late bell stage and the early bell stage respectively, with the differences of expression changes between successive developmental stages showing statistically significance ( P<0.05). Vinculin expression, however, remained at a relatively constant level except for the late bell stage when vinculin expression was slightly elevated compared to that of the early bell stage ( P<0.05). The findings suggest that mechanical stress is involved in early tooth development. F-actin may have an important role in dispersing and transmitting mechanical stress while NMⅡB may participate in tooth epithelial invagination and cusps formation. The findings also suggest that vinculin can respond to the mechanical stimuli and its interaction with cell adhesion molecules may play a role in tooth development. The mechanism of how actomyosin and cell adhesion interact with each other in regulating tooth development still needs further investigation.

Narratives about a stigma: attributing meaning to the early loss of deciduous teeth on children's caregivers.

Qualitative approach about the implications that occur succeeding the premature loss teeth is still insufficient. This study aimed to understand the experience of early loss of deciduous teeth in children's lives, from the perspective of their caregivers. Qualitative case study included 52 caregivers of children from an outpatient service of a public university in the south of Brazil. Early loss of deciduous teeth to trauma or caries was identified through analysis of health records, and afterwards, semi-structured interviews were performed. Textual material was interpreted through the content analysis proposed by Bardin, supported by the ATLAS.ti software. The theoretical perspective of stigma was guided according to the principles of the phenomenology of Maurice Merleau-Ponty, centred on the experience of early loss of deciduous teeth as a historic-cultural expression of a social group. According to caregivers, premature loss of deciduous teeth due to trauma or decay brings functional limitations with chewing and speaking, and impairments related to social interaction with other children. The repercussions of missing teeth were not limited to the child's image, but also brought changes in families' daily lives. However, when early tooth loss was due to extraction because of pain and suffering, caregivers perceived the loss as 'commonplace' in children's lives. The understanding of how children see themselves without teeth in their social world for their caregivers, which also includes their family and friends, determines how much experiencing tooth loss affects their lives. Besides, caregivers' perceptions related to early loss of deciduous teeth should be included in strategies of oral health promotion programs.

Timings of Permanent Tooth Emergence in Children of Rural Vanuatu, Melanesia

Global patterning and timing of permanent tooth emergence is influenced by ethnicity, with no known timings reported for ethnic Melanesian children living in the tropical archipelago of Vanuatu. To determine timings of permanent tooth emergence and sequencing for children who reside in rural Vanuatu. Children aged 4-17 years (n=1026), part of a larger oral health cross-sectional study, were examined recording all permanent teeth present, across four spatially separated islands. Binary logistic modelling established children’s median age of emergence of each permanent tooth for each study area. The median emergence of first permanent molars for girls is 4.9-years and 5.3 -years for boys. In all locations, children had all permanent teeth emerge by age 11 years (excluding 3rd molars). Clinically important differences exist for permanent tooth emergence by study area. Permanent teeth emerge earlier for Ni-Vanuatu children compared to both Melanesian children of Papua New Guinea as well as other ethnicities across Oceanic countries. Early tooth emergence suggests oral health education programmes should target pregnant women with clinical preventive strategies commencing for their children before 5-years of age. These results can be used as a set standard for Vanuatu. Funding Statement: The primary author of this study received funding from New Zealand Aid/Ministry of Foreign Affairs and Trade to travel to study areas. Declaration of Interests: All authors declare no conflict of interest. Ethics Approval Statement: Ethical approval for this study was granted by Victoria University of Wellington, New Zealand (approval HEC#19916). Additionally, consent was granted, at each site by local health staff, village chiefs, parents and school staff for clinical examinations (to be performed on children by a New Zealand oral health professional), with all children assenting to participate.