Assessing current clinical eruption stage of mandibular third molars by dental panoramic radiography.

OBJECTIVE: We examined whether dental panoramic radiography (PAN) can be used to identify the clinical stage of eruption of mandibular third molars at the time of radiological examination. MATERIALS AND METHODS: Cross-sectional data included records from clinical oral examination and PANs of university students. In the retrospective analysis of 345 mandibular third molars in 189 participants (20% men, 80% women; mean age 20.7 years; standard deviation [SD] ± 0.6), clinical stages of eruption were compared with their radiographic depth in bone, inclination, and root development. Statistics included χ2, Mann-Whitney U tests, and logistic regression. RESULTS: Significant (p < 0.001) predictor variables for assessing the clinical stage of eruption were radiographic depth in bone and inclination. All teeth radiologically at a depth of the cementoenamel (CE) junction of the neighbouring second molar or deeper were clinically unerupted. Above the CE junction, 80% of vertical and 97% of distoangular teeth were connected to the oral cavity, and 82% of mesioangular and 69% of horizontal teeth were clinically unerupted. CONCLUSION: All teeth below or at the CE junction are clinically unerupted. Above the CE junction, stage of eruption should be assessed together with the inclination, but horizontally inclined teeth are recommended to be verified clinically.

Radiological features and treatment of erupting maxillary canines in relation to the occurrence of dental developmental abnormalities.

OBJECTIVE: This study aimed to investigate the radiological features of the permanent canines and the treatment carried out to ensure their eruption relative to certain features involved in Dental Anomaly Patterns (DAP). MATERIAL AND METHODS: The cross-sectional part of this retrospective register--based study focused on 1,315 dental panoramic tomographs (DPTs) of children aged 8.5-10.5 years, while the longitudinal part involved information on the treatment provided for 1,269 canines after the DPTs and on their eruption into the oral cavity. RESULTS: The canines of the DAP children more often showed evidence of early treatment (p = 0.014), with girls having more frequently interceptive treatment (p = 0.004) and boys early headgear (p = 0.022). Delayed dental age was associated with early treatment (OR 3.29, 95% CI 1.08-9.99). Either no or clear overlapping of a canine with the lateral incisor occurred more often in the DAP children, whereas canine inclination did not differ between the groups. The root development stage of the canine was more often either beginning or well advanced in the DAP children. CONCLUSIONS: The children with dental developmental abnormalities more often showed evidence of early treatment for the canines. Monitoring of the erupting canines after the first mixed stage is important to enable timely early treatment.

Evaluation of tooth eruption rate of incisor teeth in rats with estrogen deficiency.

OBJECTIVES: To assess the influence of estrogen deficiency on tooth eruption rate (TER) and gene expression of estrogen receptor alpha and beta (ERα and ERß) in the odontogenic region of teeth with continuous formation in a rat model. MATERIALS AND METHODS: Ovariectomies (OVX; n = 25) and sham surgeries (SHAM; n = 25) were performed in female Wistar rats when animals were 25 days old. The TER of the lower incisors, both in impeded (hyperfunction condition) and unimpeded (trimmed incisal edge-hypofunction condition) conditions, was evaluated using standardized digital photographs acquired every 48-72 h for 3 weeks (35th-53rd day of life), using a camera coupled to a stereomicroscope. Quantitative real-time PCR was performed to evaluate the relative gene expression of ERα and ERß in the odontogenic region. RESULTS: The OVX group showed a significant reduction in TER when compared to the SHAM group, only in the impeded condition (p = 0.03). There was no statistically significant difference between the groups in ERα gene expression (p = 0.33). ERß showed a significantly higher gene expression in the OVX group (p ≤ 0.05). CONCLUSIONS: Estrogen deficiency decreases TER in teeth under impeded condition. Estrogen deficiency also increases ERß gene expression in the odontogenic region of teeth with continuous formation. CLINICAL RELEVANCE: Hormonal disturbances affecting estrogen levels can cause alterations in dental formation and teeth eruption.

Relación entre el nivel socioeconómico y la cronología y secuencia de erupción de la dentición permanente / Relationship between the socioeconomic level and the chronology and sequence of permanent dentition

Objetivo: Relacionar el proceso eruptivo en dentición permanente con el nivel socioeconómico. Métodos: Se realizó un estudio epidemiológico, descriptivo y transversal en población española, participando 725 niños/as entre 4 y 14 años, la selección fue oportunista registrando en una base de datos el nivel socioeconómico de los progenitores, la cronología y secuencia de emergencia de cada uno de los dientes permanentes. Resultados: Con respecto al nivel socioeconómico un 38,62% eran de nivel I, el 40,83% nivel II, el 15,86% nivel III, el 4,14% nivel IV y el 0,55% nivel V. El primer diente en aparecer en el maxilar fue el primer molar (74,34-76,41%), mientras que en la mandíbula fue el incisivo central (78,9-82,76%) con diferencias estadísticamente significativas (p-χ2 <0,001). Conclusiones: Del nivel socioeconómico dependerá la atención médica y nutrición de los pacientes, pero a nivel dentario no existieron diferencias estadísticamente significativas en cuanto a la cronología y secuencia de erupción (AU)

Objective: To relate the eruptive process in the permanent dentition to the socioeconomic level. Methods: An epidemiological, descriptive and cross-sectional study was carried out in a Spanish population of 725 children between 4 and 14 years of age. The selection was opportunistic, recording in a database the socioeconomic level of the parents, the chronology and sequence of emergence of each of the permanent teeth. Results: In relation to the socioeconomic status, the 38,62% belong to level I, the 40,83% to the level II, the 15,86% to the level III, the 4,14% to the level IV and the 0,55% to the level V. Regarding the first tooth to emerge in the maxilla was the first molar (74,34% - 76,41%) and in the mandible was the central incisor (78,9%-82,76%) with statistically significant differences (p-χ2 <0,001). Conclusions: The patient’s medical care and nutrition will depend on their socioeconomic level, but at the dental level there (AU)

Multiple roles of Runt-related transcription factor-2 in tooth eruption: bone formation and resorption.

OBJECTIVE: The aim was to provide a comprehensive review of the current knowledge of the multiple roles of Runt-related transcription factor-2 (RUNX2) in regulating tooth eruption, focusing on the molecular mechanisms regarding tooth eruption mediated by RUNX2. DESIGN: Relevant literatures in PubMed, Medline, and Scopus database were searched, and a narrative review was performed. The multiple roles of RUNX2 in regulating tooth eruption was reviewed and discussed. RESULTS: Aberrant RUNX2 expression leads to disturbed or failed tooth eruption. Tooth eruption involves both the process of bone formation and bone resorption. RUNX2 promotes osteogenesis around the radicular portion of the dental follicle that provides the biological force for tooth eruption through inducing the expression of osteogenesis-related genes in dental follicle cells/osteoblasts. On the other hand, through indirect and direct pathways, RUNX2 regulates osteoclastogenesis and the formation of the eruption pathway. CONCLUSION: RUNX2 exerts a pivotal and complex influence in regulating tooth eruption. This review provides a better understanding of the function of RUNX2 in tooth eruption, which is beneficial to illuminate the precise molecular mechanism of osteogenesis and bone resorption, aiding the development of effective therapy for the failure of tooth eruption.

Cronología y secuencia de erupción de la dentición permanente. Actualización en la población infantil española / Chronology and sequence of the permanent dentition. A review in spanish children population

Estudiar la emergencia y secuencia deerupción es indispensable para establecer protocolos de prevención y tratamientos a nivel odontopediátrico, ortodóncicoy forense. En 1933 se estableció el iniciode la erupción definitiva a los 6 años y sutérmino a los 13 a excepción de los cordales. Sin embargo, posteriormente se hanobservado variaciones determinadas porfactores raciales, hormonales, mejoras enla alimentación y parámetros corporales.Con el objetivo de conocer posibles cambios en la cronología y secuencia de erupción en dentición permanente y poblaciónespañola se ha llevado a cabo una búsqueda bibliográfica en los buscadoresPubmed, Scielo, Dentistry y Oral Science.Empleando una estrategia avanzada conoperadores boleanos “AND” y “OR”. Losresultados obtenidos advierten de unaemergencia de la dentición permanentemás precoz en el sexo femenino. Los autores coinciden en que el primer diente enerupcionar es el incisivo central inferior yel último el segundo molar superior. Sinembargo, en cuanto a la edad media dela emergencia del primer diente no hayconsenso.Los dientes permanentes mandibulareserupcionaban antes que los maxilares.La secuencia de erupción más prevalente en la Arcada superior es: primer molar, incisivo central, incisivo lateral, primerpremolar, segundo premolar, canino ysegundo molar. Y en la inferior: incisivocentral, primer molar, incisivo lateral, canino, primer premolar, segundo premolary molar. Se concluyó que existía una correlación directa entre el tiempo de erupción de los dientes temporales y la de los permanentes canine, first premolar, second premolar and second molar.To conclude, we noticed an extremely direct relation between the eruption time of the temporal teeth and thepermanent teeth (AU)

In order, to develop prevention andtreatment protocols in pediatric,orthodontic and forensic dentistry, it isvitally needed to study the sequence andchronology of eruption of the permanentteeth. Logan and Kronfield establishedthat the eruption of permanent teethstarted at the age of six and finished atthe age of 13, except the third permanentmolars. Nevertheless, in later studies thisrange of age has been modified due toan early puberty, an improvement in thenutrition and due to other factors, suchas, race, weight, and heigh. Our objectiveis to get to know the current situationabout the chronology and sequence ofpermanent dentition.We did a bibliographic review in differentweb browsers, such as, PubMed, Scieloand Dentistry and Oral Science. Weapplied an advanced strategy searchingwith “AND” and “OR”. The results warn usthat the permanent teeth erupted earlieralways in the female sex. All the authorsagree that the first tooth to erupt is thelower central incisor and the last one isthe upper second molar. Despite this fact,regarding the media age of eruption therewas not agreement between the authors.Therefore, we can conclude thatpermanent teeth erupt before in themandible than in the maxilar. The mostprevalent sequence in the maxilar was:first molar, central incisor, lateral incisor,first premolar, second premolar, canineand second molar. In the mandible was:central incisor, first molar, lateral incisor(AU)

Symptoms of the Eruption of Permanent Teeth.

This prospective study examined a population of 520 urban and rural children aged 5 to 9 years. Every 2−4 weeks, the clinical symptoms accompanying primary tooth replacement such as a cough, a runny nose, pain, and body temperature were assessed in each child's medical records. The authors were able to show in a statistically significant manner that the frequency, time, and type of cough were strongly related to the type of erupting teeth (p < 0.001 for each relationship). A cough dependent on the type of erupting teeth was observed in 86% to 92% of the examined children, with a morning bronchial cough being connected with an eruption of the lower teeth, and an eruption of the upper teeth producing an all-day pharyngeal cough caused by mucus secretions dripping down the back of the throat. A statistically significant relationship was also confirmed between the type of erupting teeth and the incidence of a runny nose (p < 0.001), the frequency of a runny nose (p < 0.001), and the time when runny nose symptoms occurred (p < 0.001). This study shows that the period when primary dentition is replaced with permanent teeth in children is characterized by a physiological cough and a runny nose.

Revisiting the human dental follicle: From tooth development to its association with unerupted or impacted teeth and pathological changes.

Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age-related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology.

Odontomas: un reto para el tratamiento interdisciplinario del paciente de ortodoncia / Odontomas: a challenge for the interdisciplinary treatment of the orthodontic patient

El objetivo del presente trabajo es describir las técnicas para el diagnóstico y tratamiento de 3 casos clínicos de odontoma en pacientes ortodóncicos. En el caso 1, se trató a un paciente masculino de 17 años, que acudió para interconsulta con el servicio de ortodoncia, ya que no había erupcionado el canino superior izquierdo y el primer premolar superior izquierdo. El estudio anatomopatológico reveló odontoma complejo con áreas pindborgoides y acumulación de células fantasma. En al caso 2 se trató a un paciente femenino de 15 años. El estudio anatomopatológico reveló odontoma complejo. En el caso 3, se trató a un paciente masculino de 28 años que acudió a rehabilitación integral de su boca, y fue derivado a la cátedra de ortodoncia. En la radiografía panorámica se observó una imagen compatible con odontoma. Se remitió una muestra a anatomía patológica que confirmó el diagnóstico de odontoma. Conclusión: el conocimiento adecuado de las características clínicas, radiológicas y patológicas es necesario para un correcto diagnóstico y tratamiento. Es importante el trabajo interdisciplinario ortodoncista - cirujano para tratar estos casos (AU)

The objective of this work is to describe the techniques for the diagnosis and treatment of 3 clinical cases of odontoma in orthodontic patients. In case 1, a 17-year-old male patient was treated who came for consultation with the orthodontic service, since the upper left canine and the upper left first premolar had not erupted. Pathological study revealed complex odontoma with pindborgoid areas and accumulation of ghost cells. In case 2, a 15-year-old female patient was treated. The anatomopathological study revealed a complex odontoma. In case 3, a 28-year-old male patient was treated who attended comprehensive rehabilitation of his mouth and was referred to the orthodontic department. In the panoramic radiography, an image compatible with odontoma was observed. A sample was sent to pathological anatomy, which confirmed the diagnosis of odontoma. Conclusion: Adequate knowledge of the clinical, radiological and pathological characteristics is necessary for a correct diagnosis and treatment. Interdisciplinary orthodontist-surgeon work is important to treat these cases (AU)

Application of cryopreservation to tooth germ transplantation for root development and tooth eruption.

We cryopreserved mouse tooth germs with widely open cervical margins of the enamel organ to overcome difficulties in cryoprotectant permeation and tested their efficacy by transplanting them into recipient mice. The upper right first molar germs of 8-day-old donor mice were extracted and categorized into the following four groups according to cryopreservation time: no cryopreservation, 1 week, 1 month, and 3 months. The donor tooth germs were transplanted into the upper right first molar germ sockets of the 8-day-old recipient mice. The upper left first molars of the recipient mice were used as controls. The outcome of the transplantation was assessed at 1, 2, and 3 weeks after transplantation. Stereomicroscopic evaluation revealed that most of the transplanted teeth erupted by 3 weeks after transplantation. Micro-computed tomography analysis revealed root elongation in the transplanted groups as well as in the controls. There was no significant difference between the cryopreserved and non-cryopreserved transplanted teeth, but the roots of the cryopreserved teeth were significantly shorter than those of the control teeth. Histological examination revealed root and periodontal ligament formations in all the transplanted groups. These results suggest that the transplantation of cryopreserved tooth germs facilitates subsequent root elongation and tooth eruption.

New cladotherian mammal from southern Chile and the evolution of mesungulatid meridiolestidans at the dusk of the Mesozoic era.

In the last decades, several discoveries have uncovered the complexity of mammalian evolution during the Mesozoic Era, including important Gondwanan lineages: the australosphenidans, gondwanatherians, and meridiolestidans (Dryolestoidea). Most often, their presence and diversity is documented by isolated teeth and jaws. Here, we describe a new meridiolestidan mammal, Orretherium tzen gen. et sp. nov., from the Late Cretaceous of southern Chile, based on a partial jaw with five cheek teeth in locis and an isolated upper premolar. Phylogenetic analysis places Orretherium as the earliest divergence within Mesungulatidae, before other forms such as the Late Cretaceous Mesungulatum and Coloniatherium, and the early Paleocene Peligrotherium. The in loco tooth sequence (last two premolars and three molars) is the first recovered for a Cretaceous taxon in this family and suggests that reconstructed tooth sequences for other Mesozoic mesungulatids may include more than one species. Tooth eruption and replacement show that molar eruption in mesungulatids is heterochronically delayed with regard to basal dryolestoids, with therian-like simultaneous eruption of the last premolar and last molar. Meridiolestidans seem endemic to Patagonia, but given their diversity and abundance, and the similarity of vertebrate faunas in other regions of Gondwana, they may yet be discovered in other continents.

Expression of fibroblast growth factor receptor1, -2c, and -3c transcripts in mouse molars after tooth eruption.

A previous study suggested that fibroblast growth factor (FGF) signaling plays an important role in dentin formation during tooth development. In this study, to examine dentin formation after tooth eruption involving secondary and tertiary dentin, we analyzed the expression patterns and expressing cells of Fgfr1, -2c, and -3c in mouse maxillary first molars (M1). Since it is difficult to recover the mRNAs from mineralized tissues, we tested methods for extraction after fixation and decalcification of teeth. We successfully obtained consistent results with quantitative real-time PCR (qPCR) using ß-actin transcripts for validation. qPCR for Dentin sialo phosphoprotein (Dspp), Fgfr1, -2c, and -3c transcripts was performed on mice at ages of 2-20 weeks. The results showed that the highest expression levels of Dspp and Fgfr2c occurred at 2 weeks old followed by lower expression levels after 4 weeks old. However, the expression levels of Fgfr1 and Fgfr3c were constant throughout the experimental period. By in situ hybridization, Dspp, Fgfr1, and Fgfr3c transcripts were detected in odontoblasts at ages of 2 and 4 weeks. In addition, Dspp and Fgfr1 transcripts were detected in odontoblasts facing reactionary dentin at 8 weeks old. These results suggest that FGF-FGFR signaling might be involved in the regulation of odontoblasts even after tooth eruption, including secondary and tertiary dentin formation. Moreover, our modified method for extracting mRNA from mineralized tissues after fixation and decalcification successfully produced consistent results.

Miniaturization: How many cells are needed to build a tooth?

BACKGROUND: Organs that develop early in life, and are replaced by a larger version as the animal grows, often represent a miniature version of the adult organ. Teeth constituting the first functional dentition in small-sized teleost fish, such as medaka (Oryzias latipes), are examples of such miniature organs. With a dentin cone as small as the size of one human cell, or even smaller, these teeth raise the question how many dentin-producing cells (odontoblasts) are required to build such a tooth, and whether this number can be as little as one. RESULTS: Based on detailed observations with transmission electron microscopy (TEM) and TEM-based 3D-reconstructions, we show that only one mesenchymal cell qualifies as a true odontoblast. A second mesenchymal cell potentially participates in dentin formation, but only at a late stage of tooth development. Moreover, the fate of these cells appears to be specified very early during tooth development. CONCLUSIONS: Our observations indicate that in this system, one single odontoblast fulfills roles normally exerted by a large and communicating cell population. First-generation teeth in medaka thus provide an exciting model to study integration of multiple functions into a single cell.

Assessment of Age at the Stages of the Eruption of Third Molar Teeth among the People of North-Eastern India.

METHODS: A cross-sectional descriptive and analytical study was undertaken with 1060 Assamese individuals (642 males and 418 females) aged 14-26 years and was subjected to a clinical, dental, and general physical examination from January 2014 to December 2018. The data were statistically analyzed using Microsoft Excel and the Statistical Package for the Social Sciences (SPSS) version 22. The significant differences among variables were tested using the chi-square test and Student's t-test, considering a p value < 0.05 as significant. RESULTS: The carried-out research showed no eruption (NE) status of M3 with an overall mean (±SD) age at 17.39 (±2.273) years, although a significantly lower age among males with a mean age of 16.92 (±2.138) years (p value < 0.001) was observed. The mean age (overall) for the complete eruption (CE) was observed at 20.33 (±2.566) years, which was seen earlier in males. The mandibular M3 appears earlier compared to the maxillary M3. The third molar eruption (TME) on both left and right quadrants of the jaw was observed substantially earlier in the lower jaw, compared to the upper jaw (p value < 0.025). The earliest CE of M3 was marked at 15 years. The differences in the frequencies of TME in different chronological age groups were found significant (p value < 0.001). A significant association between gender and TME (p value < 0.045) in the current study is worth noting. CONCLUSION: Thus, determined by TME as a valid method, age can be used for various purposes to establish a person's identity. Dental age estimated using third molar eruption status has a weighty association with chronological age. Thus, it should be utilized to determine the likely age of an individual.

Above or below 14 years? An orthopantomographic study based on chronological course of eruption of mandibular premolars and second molars in a sample of south Indian children.

In the context of dental age assessment, two significant factors can be studied; tooth mineralisation and tooth emergence. Little is known about the role of a second molar eruption in forensic age estimation. This paper aims to contribute to forensic age estimation using an age threshold of 14 years, studying the eruption stages of permanent mandibular premolars and second molars. Totally 640 orthopantomograms (OPGs) of south Indian children, aged between 10 and 18 years, were evaluated using Olze et al. staging of tooth eruption stages (A-D). Spearman's rho correlation showed a strong, positive, and statistically significant correlation between the chronological age and the eruption stages of both sexes' teeth. Accuracy, sensitivity, specificity, likelihood ratios, and post-test probability values were calculated for all tested teeth. The best performance to discriminate individuals above or below 14 years showed stage D in second molars. The sensitivity varied between 89% and 94% and specificity between 75% and 84%, respectively. Receiver operating characteristic curve analysis revealed high diagnostic performance for stage D, with area under the ROC curve (AUC) values of 84% and 85% for tooth 37 and 85% and 83% for tooth 47 in males and females, respectively. In conclusion, it is possible to predict age over 14 years in south Indian children using tooth emergence stages from OPGs with a relatively high interobserver agreement and good diagnostic accuracy. However, there are some limitations and, therefore, must be used in conjunction with other methods.

Age and Sequence of Permanent Teeth Eruption in Lebanese Children.

BACKGROUND: The timing of eruption of permanent teeth can be a precious help to the pediatric practitioner in identifying an appropriate treatment plan. Usually, it presents a more precise sign of an early or late growth of the child. AIMS: It is to determine whether the timing of the permanent teeth eruption in Lebanese pediatric population can be considered as standard Lebanese values, since no other study was previously performed. MATERIALS AND METHODS: A cross-sectional study is conducted, and the clinical emergence data are collected for a sample of 2317 Lebanese children aged between 5.5 years and 13 years (1129 girls and 1188 boys) from different socioeconomic groups in rural and urban communities spread over different regions in Lebanon. The study investigates dental emergence patterns. RESULTS: Statistical analysis is performed with the SPSS Software. A confidence interval of 95% and significance level of 5% are adopted. The trend is for males to begin their permanent teeth eruption later than girls. Emergence of all permanent mandibular teeth is earlier than maxillary ones. Symmetry is found between the right and left teeth in the maxilla, as well as in the mandibula. CONCLUSION: In this study, the results indicate that premolars and second permanent molars erupt earlier in the Lebanese children compared to children of other countries reflected in several studies.

Age at first molar emergence in Pan troglodytes verus and variation in the timing of molar emergence among free-living chimpanzees.

Age at lower first molar (M1) emergence is a commonly used proxy for inferring life-history scheduling in fossil primates, but its utility is dependent on knowing to what extent extant populations vary in this datum and how this variation correlates with the scheduling of life-history variables. Here, we address the first of these issues among extant chimpanzees. While age at M1 emergence has been documented in several live individuals from the Kanyawara population of Pan troglodytes schweinfurthii in Uganda, it has been estimated for only one individual of Pan troglodytes verus, based on a deceased animal from the Taï Forest in Côte d'Ivoire. To further explore interpopulation variation in this variable in chimpanzees, and using dental histology, we calculated ages at death for two wild-shot individuals of P. t. verus with erupting M1, both collected in Liberia during the mid-1950s, and estimated ages at M1 emergence from the ages at death. The overall range for these two individuals is ∼4.2-4.6 yr, compared with an age of ∼3.7 yr for the individual from the Taï Forest, and <2.5-3.3 yr for the several individuals of P. t. schweinfurthii. While the absolute range of ∼2 yr in these samples combined is little greater than in captive chimpanzees, the disparity between the samples of P. t. schweinfurthii and P. t. verus is striking, although it cannot be determined if this disparity represents a subspecies difference or simply population differences expressed in two different subspecies. While life-history data are unavailable for the population to which the Liberian chimpanzees belonged, the difference in M1 emergence ages between these individuals and those from Kanyawara still suggests caution when attempting even broad life-history inference in fossil apes and hominins based on age at M1 emergence.

Depth of Gingival Sulcus in Healthy Children with Erupting Permanent Teeth.

INTRODUCTION: Measuring the gingival sulcus depth in children while their permanent teeth erupt is rather difficult especially if using reference norms for adults for a base. AIM: Assessment of the depth of the gingival sulcus during the period of tooth eruption in healthy children. MATERIALS AND METHODS: Thirty children were included in the study (age range 6 - 14 yrs). The children had good oral hygiene and no history of systemic disease. They were clinically examined - their dental statuses were taken, stages of permanent teeth eruption (up to 1/3 of the clinical crown, between 1/3 and 2/3, over 2/3, in occlusion contact), and their gingival sulcus depth was measured at 6 distovestibular, vestibular, mesiovestibular, mesiolingual, lingual, and distolingual sites using an electronic probe Parometer (Orange). It was concluded that the one with the highest value would be considered the maximum depth of the sulcus. RESULTS: The gingival sulcus depth in fully erupted teeth is very similar to that in healthy adults (2.20 - 0.49 mm). The change of sulcus depth in incisors and canines has a variation of 1.5 mm, which at the end of eruption is close to those in adults. Maximum sulcus depth for molars, premolars and incisors was measured distovestibularly, and for canines - mesiovestibularly. CONCLUSION: At the various stages of eruption, the depth of the gingival sulcus plausibly decreases in all tooth types, and by the end of eruption it reaches a depth similar to that of the adult standard. Most indicative in regard to depth are the vestibular probing point.

Early Weight Gain Forecasts Accelerated Eruption of Deciduous Teeth and Later Overweight Status during the First Year.

OBJECTIVES: To determine whether early diet and weight gain velocity have independent or interactive effects on deciduous teeth emergence and overweight status during the first year. STUDY DESIGN: Monthly measures of anthropometry and teeth eruption were collected during a 1-year trial (0.5-12.5 months) on formula-fed infants in which the type of randomized infant formula (cow milk or extensively hydrolyzed protein) diet significantly affected early (0.5-4.5 months) weight gain velocity. Generalized linear mixed models determined whether early diet and weight gain velocity had independent or interactive effects on timing and pattern of teeth eruption. Data from a trial on breastfed infants were used to explore effects of breast milk vs infant formula diets on teeth eruption and overweight status at 10.5 months. RESULTS: Independent of infant formula diet, velocities of weight gain had direct effects on the age of first deciduous tooth (P < .04) and number of erupted teeth over time (P < .002). Greater velocity of weight gain from 0.5 to 4.5 months caused earlier and more frequent eruption of deciduous teeth from 4.5 to 12.5 months. Exploratory follow-up analyses on the breastfed and formula-fed diet groups found early weight gain velocity (P = .001), but not diet or its interaction, had significant effects. Infants in the upper quartile for weight gain velocity had more primary teeth (P = .002), and a greater proportion of them were overweight (P < .001) at 10.5 months. CONCLUSIONS: Faster weight gain accretion forecasted accelerated primary teeth eruption and increased percentage of children who were overweight-risk factors for dental caries and obesity. TRIAL REGISTRATION: ClinicalTrials.govNCT01700205 [2012-2015] and NCT01667549 [2012-2015].

Costly teeth? Gestation length in primates suggests that neonate dentition is not expensive to produce.

Variation in the relationship between gestation length and body mass can arise because different types of tissue require varying amounts of energy to build, and not all species build such tissues in the same proportions. Given that a pregnant female has a finite amount of energy, trade-offs between investment in different tissues may occur. Here we examine if dental precocity accounts for variation in primate gestation length. If true, this could explain why folivorous species with precocial dentition have longer gestation lengths than predicted by neonatal brain and body mass. We compiled data on gestation length, neonate and adult female body and brain mass from the literature. We used published postcanine eruption schedules at 4 months of age and measured the total occlusal area as dental endowment to approximate dental precocity at birth. Species with embryonic delay in growth or altricial neonates were not considered because they represent grade shifts regarding gestation length. Consequently, our data were biased toward Simiiformes and Old World monkeys, specifically. We performed a phylogenetic generalized least squares regression (pGLS) of neonate brain mass in relation to neonate body mass, and a second pGLS with dental endowment as an additional predictor variable. Including dental endowment in the pGLS did not improve the model. Dental endowment did not systematically impact primate gestation length. Concordant with results from previous studies, this indicates that the energetically expensive period of tooth mineralization may occur postnatally. More data are required to examine if the results are typical across primates.