Evolution of tooth morphological complexity and its association with the position of tooth eruption in the jaw in non-mammalian synapsids.

Heterodonty and complex molar morphology are important characteristics of mammals acquired during the evolution of early mammals from non-mammalian synapsids. Some non-mammalian synapsids had only simple, unicuspid teeth, whereas others had complex, multicuspid teeth. In this study, we reconstructed the ancestral states of tooth morphological complexity across non-mammalian synapsids to show that morphologically complex teeth evolved independently multiple times within Therapsida and that secondary simplification of tooth morphology occurred in some non-mammalian Cynodontia. In some mammals, secondary evolution of simpler teeth from complex molars has been previously reported to correlate with an anterior shift of tooth eruption position in the jaw, as evaluated by the dentition position relative to the ends of component bones used as reference points in the upper jaw. Our phylogenetic comparative analyses showed a significant correlation between an increase in tooth complexity and a posterior shift in the dentition position relative to only one of the three specific ends of component bones that we used as reference points in the upper jaw of non-mammalian synapsids. The ends of component bones depend on the shape and relative area of each bone, which appear to vary considerably among the synapsid taxa. Quantification of the dentition position along the anteroposterior axis in the overall cranium showed suggestive evidence of a correlation between an increase in tooth complexity and a posterior shift in the dentition position among non-mammalian synapsids. This correlation supports the hypothesis that a posterior shift of tooth eruption position relative to the morphogenetic fields that determine tooth form have contributed to the evolution of morphologically complex teeth in non-mammalian synapsids, if the position in the cranium represents a certain point in the morphogenetic fields.

Exploring the factors driving higher interactions in false amber necklace posts on Facebook.

The consumption and sharing of information on social media contribute to the circulation of false health content. In this sense, popular belief-driven posts recommending the use of amber necklaces to prevent symptoms of teething can be easily found on social media, even when they offer health risks for children. Accordingly, this study aimed to characterize posts in Portuguese by identifying message-based factors associated with higher user interactions of Facebook. A total of 500 Facebook posts published in Portuguese between August 2016 and August 2021 were retrieved by CrowdTangle, and analyzed quantitatively according to time of publication, total user interaction, and post overperforming score, and then qualitatively by two independent investigators, according to motivation, authors' profiles, and sentiment. The data were evaluated by descriptive analysis, Mann-Whitney U test, chi-square test, and multiple logistic regression models regarding interaction metrics. The posts were published predominantly by commercial profiles, with social, psychological, and financial motivations, and expressed positive sentiment. Furthermore, time of publication (OR=2.65), regular user profiles (OR=3.30), and neutral/negative sentiment (OR=2.76) were associated positively with total interactions, whereas only time of publication was associated with post overperforming scores (OR=1.65). In conclusion, Facebook posts promoting efficacy of amber necklaces in managing teething symptoms are primarily created by commercial profiles with vested interests in marketing the product. The key factors that contribute to the success of posts containing false information about amber necklaces on Facebook can be identified by considering the author's profile, sentiment, and time of publication.

How do teeth erupt?

The development of normal occlusion requires eruptive migration of teeth from their developmental position in the jaw into a functional position within the oral cavity. This process involves significant and coordinated movement in an axial direction and appropriate eruption through the gingival tissues. The mechanisms regulating these developmental events are poorly understood, and teeth retain eruptive potential throughout their lifespan. In recent years, the use of mouse models has helped to elucidate some of the underlying molecular and biological mechanisms of mammalian tooth eruption. Here, we outline our current understanding of tooth eruption mechanisms and discuss their relevance in terms of known human disorders of tooth eruption.

The effect of occlusal loading on secondary tooth eruption: An experimental study using a rat model.

This study aimed to assess the impact of occlusal loading on secondary tooth eruption and to determine the extent to which altering the occlusal loading influences the magnitude of secondary eruption through an experimental rat model. The present sample consisted of 48 male Wistar rats. At the onset of the experiment, 24 rats were 4 weeks old (young rats) and 24 rats were 26 weeks old (adult). Within each age group, the rats were further divided into two equal subgroups (12 rats each), receiving either a soft- or hard-food diet for the 3-month duration of the experiment. The primary outcome was the tooth position changes relative to stable references in the coronal plane by evaluating the distance between the mandibular first molars and the inferior alveolar canal. Microcomputed tomography scans were taken from all rats at three standardized intervals over the 3-month study period. Descriptive statistics were calculated by age and diet over time, and the evolution of the outcomes were plotted by age and diet over time. Longitudinal data analysis via generalized estimating equations was performed to examine the effect of age, diet and time on the primary outcomes. Secondary tooth eruption was observed in all age groups (young and adult) regardless of diet consistency (soft or hard food). In young rats, the secondary eruption was greater in the animals fed a soft diet than those fed a hard diet. In adult rats, minimal difference in secondary tooth eruption were found between different diet consistencies. Occlusal loading influences secondary tooth eruption in teeth with an established occlusal contact. The quantity of eruption in growing rats is higher when occlusal loading is less, providing a certain amount of secondary tooth eruption occurs. This difference, however, is not evident in adult rats, at least during the given 3-month time frame.

Jurassic fossil juvenile reveals prolonged life history in early mammals.

Living mammal groups exhibit rapid juvenile growth with a cessation of growth in adulthood1. Understanding the emergence of this pattern in the earliest mammaliaforms (mammals and their closest extinct relatives) is hindered by a paucity of fossils representing juvenile individuals. We report exceptionally complete juvenile and adult specimens of the Middle Jurassic docodontan Krusatodon, providing anatomical data and insights into the life history of early diverging mammaliaforms. We used synchrotron X-ray micro-computed tomography imaging of cementum growth increments in the teeth2-4 to provide evidence of pace of life in a Mesozoic mammaliaform. The adult was about 7 years and the juvenile 7 to 24 months of age at death and in the process of replacing its deciduous dentition with its final, adult generation. When analysed against a dataset of life history parameters for extant mammals5, the relative sequence of adult tooth eruption was already established in Krusatodon and in the range observed in extant mammals but this development was prolonged, taking place during a longer period as part of a significantly longer maximum lifespan than extant mammals of comparable adult body mass (156 g or less). Our findings suggest that early diverging mammaliaforms did not experience the same life histories as extant small-bodied mammals and the fundamental shift to faster growth over a shorter lifespan may not have taken place in mammaliaforms until during or after the Middle Jurassic.

Etiological Mechanisms and Genetic/Biological Modulation Related to PTH1R in Primary Failure of Tooth Eruption.

Primary failure of eruption (PFE) is a rare disorder that is characterized by the inability of a molar tooth/teeth to erupt to the occlusal plane or to normally react to orthodontic force. This condition is related to hereditary factors and has been extensively researched over many years. However, the etiological mechanisms of pathogenesis are still not fully understood. Evidence from studies on PFE cases has shown that PFE patients may carry parathyroid hormone 1 receptor (PTH1R) gene mutations, and genetic detection can be used to diagnose PFE at an early stage. PTH1R variants can lead to altered protein structure, impaired protein function, and abnormal biological activities of the cells, which may ultimately impact the behavior of teeth, as observed in PFE. Dental follicle cells play a critical role in tooth eruption and root development and are regulated by parathyroid hormone-related peptide (PTHrP)-PTH1R signaling in their differentiation and other activities. PTHrP-PTH1R signaling also regulates the activity of osteoblasts, osteoclasts and odontoclasts during tooth development and eruption. When interference occurs in the PTHrP-PTH1R signaling pathway, the normal function of dental follicles and bone remodeling are impaired. This review provides an overview of PTH1R variants and their correlation with PFE, and highlights that a disruption of PTHrP-PTH1R signaling impairs the normal process of tooth development and eruption, thus providing insight into the underlying mechanisms related to PTH1R and its role in driving PFE.

Early onset of enamel formation in Baka pygmy's deciduous canines.

OBJECTIVE: Our aim was to evaluate by enamel microstructure analysis two hypotheses that would explain the early dental eruption in the Bakaparticularity, a shorter crown formation time and/or earlier onset of crown formation. DESIGN: Deciduous canines corresponds to the best teeth to perform the analysis of enamel microstructure. Longitudinal ground sections of 21 deciduous canines from 12 individuals were studied with transmitted light microscopy. Cross-striations, striaes of Retzius (SR) and the neonatal line (NNL) enable to establish the prenatal crown formation time (preCFT), the postnatal crown formation time (postCFT), the crown formation time (CFT) as well as the daily secretion rate (DSR) and the enamel extension rate (EER) and their variation along crown formation. RESULTS: The DSR and the EER in the Baka are similar than in other populations with an average DSR of 3.26 µm and EER of 18.18 µm. The preCFT was 154 days, the postCFT 265 days and CFT 419 days. Comparison with other population does not show difference in CFT. However, the preCFT and the postCFT differ, the first is higher and the second lower in the Baka than in other populations. Furthermore, the number of prenatal areas of enamel was greater in the Baka. CONCLUSION: Our analysis suggests that the Baka does not distinguish by a different CFT but the onset of crown formation is earlier than in other groups. Therefore, the early dental eruption in the Baka results from an earlier onset of crown formation.

Third molar eruption in dental panoramic radiographs as a feature for forensic age assessment - new reference data from a German population.

Forensic age assessment in the living can provide legal certainty when an individual's chronological age is unknown or when age-related information is questionable. An established method involves assessing the eruption of mandibular third molars through dental panoramic radiographs (PAN). In age assessment procedures, the respective findings are compared to reference data. The objective of this study was to generate new reference data in line with the required standards for mandibular third molar eruption within a German population. For this purpose, 605 PANs from 302 females and 303 males aged 15.04 to 25.99 years were examined. The PANs were acquired between 2013 and 2020, and the development of the mandibular third molars was rated independently by two experienced examiners using the Olze et al. staging scale from 2012. In case of disagreement in the assigned ratings, a consensus was reached through arbitration. While the mean, median and minimum ages were observed to increase with each stage of mandibular third molar eruption according to the Olze method, there was considerable overlap in the distribution of age between the stages. The minimum age for stage D, which corresponds to complete tooth eruption, was 16.1 years for females and 17.1 years for males. Thus, the completion of mandibular third molar eruption was found in both sexes before reaching the age of 18. In all individuals who had at least one tooth with completed eruption and who were younger than 17.4 years of age (n = 10), mineralization of the teeth in question was not complete. Based on our findings, the feature of assessing mandibular third molar eruption in PAN cannot be relied upon for determining age of majority.

Late Eruption of Mandibular Central Incisor in Small for-Gestational-Age Infants: A Cohort Study.

Purpose: To evaluate the chronology of the eruption of primary mandibular central incisors in infants born preterm and with low weight (PLBW) and its association with weight/length ratio for gestational age (GA) at birth, individual characteristics and hospitalization at birth. Methods: A cohort of 46 infants was followed at a multidisciplinary reference center at a university hospital in Belo Horizonte, Brazil. The inclusion criteria were infants born preterm with low/very low/extreme low birth weight and at least four months of age. Oral clinical examinations were carried out by a calibrated dentist for a total of eight months, with a one-month interval between each examination, to verify the chrono- logy of eruption of the primary mandibular central incisors. Caregivers completed a sociodemographic and health questionnaire. Data on neonatal hospitalization were collected from medical records. Data were analyzed with the Kaplan-Meier method and log rank test, and bivariate analysis was done using the Mann-Whitney method and Kruskal-Wallis test (P <0.05). Results: The average age at eruption of primary lower central incisors was 11 months for both sexes. No association was found between tooth eruption and child hospitalization or individual characteristics (P >0.05). Infants large for gestational age had earlier tooth eruption (9.3±1.41 months) than infants small for gestational age (13.6±3.29 months; P <0.05).Conclusion: The most likely age for the eruption of the first primary teeth in infants born preterm and with low weight was 11 months, and there was no influence of individual characteristics and hospitalization at birth. Small-for-gestational age infants experienced delayed tooth eruption compared to large-for-GA infants.

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.

Global variations in eruption chronology of permanent teeth: A systematic review and meta-analysis.

OBJECTIVES: Population-based variations have been reported in permanent teeth eruption but only sparse literature exists on the same. A systematic review and meta-analysis were performed to assess the global variations in eruption chronology of permanent teeth in children and adolescents and the role of sexes, jaws and classes of socio-economic status (SES) on timing of eruption was explored. METHODS: The protocol for the systematic review was registered in PROSPERO. An extensive search of PubMed, EMBASE, Google Scholar, EBSCO, Cochrane library, and anthropology databases was carried out until April 2023. Additionally, grey literature search and hand-searching of relevant key journals was done. RESULTS: Overall, 3797 cross-sectional and longitudinal studies were retrieved from multiple databases. A total of 939, 191 participants were included from 80 studies of which, 41 were carried out in Asia, 26 in Europe, 5 in Africa, 4 in North America, and 4 in Oceania. The mandibular first molar eruption was found to be as early as 4.09 years while the maxillary second molar erupted as late as 13.45 years. Using a random effects model, 28 forest plots were generated. Meta-regression interpreted tooth eruption to be earlier in females and in the mandible. CONCLUSIONS: The findings of this study show that the ages of permanent teeth eruption was advanced in the European population followed by Africa and Asia.

Developmental characteristics of the permanent upper lateral incisor in unilateral cleft lip and palate.

OBJECTIVES: This study aims to provide insights into the developmental characteristics of the upper lateral incisor in individuals with unilateral clefts. MATERIALS AND METHODS: Panoramic radiographs of a consistent group of Caucasian children taken over time (ages 6, 9, and 12) were extensively reviewed. The study assessed the distribution pattern, eruption path, tooth development, and crown size of the upper lateral incisor within the cleft region. RESULTS: The most commonly observed distribution pattern was the lateral incisor located distal to the cleft, accounting for 49.2% of cases. Furthermore, a significant delay in tooth development of the upper lateral incisor on the cleft side was noted at ages 6 and 9 (p > 0.001). Compared with the non-cleft side, these incisors often erupted along the alveolar cleft and exhibited microdontia (88.3%, p < 0.041). CONCLUSION: Lateral incisors on the cleft side display unique distribution patterns, microdontia, and delayed tooth development. Careful monitoring of the cuspid eruption is essential, as it can influence the eruption of the lateral incisor. CLINICAL RELEVANCE: A comprehensive understanding of the development of the upper lateral incisor relative to the cleft is vital for determining its prognosis over time. The position of the upper lateral incisor can also influence the timing and prognosis of secondary alveolar bone grafting. Preserving the upper lateral incisor favors arch length, perimeter, and symmetry in individuals with unilateral clefts.

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)

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)

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)

Impactación Canina Maxilar y Reabsorción Radicular de Dientes Adyacentes: Un Análisis a Través de Tomografía Computarizada Cone-Beam / Canine Maxillary Impaction and Root Resorption of Adjacent Teeth: An Analysis through Cone-Beam Computed Tomography Analysis

RESUMEN: Uno de los problemas con mayores consecuencias tanto estéticas como funcionales en ortodoncia es la impactación de caninos maxilares (ICM) siendo principal motivo de reabsorciones radiculares de dientes adyacentes. Actualmente se carece de estudios que describan la reabsorción radicular por ICM a través de tomografía computarizada conebeam (TCCB) en la población chilena. El objetivo del estudio fue describir a pacientes entre 8 a 18 años, que presentan ICM (o riesgo de ella), tanto en las características de la impactación canina como en la reabsorción radicular presentada en incisivos laterales (IL) y en otros dientes adyacentes. En este estudio retrospectivo, 135 datos de TCCB fueron seleccionados por conveniencia, de los cuales 181 caninos presentaron ICM. Fueron analizadas las variables edad, sexo, tipo de ICM (unilateral o bilateral), localización bucolingual (vestibular o palatino), lado de impactación (derecho o izquierdo), reabsorción radicular en el incisivo lateral y registro de el o los dientes anexos afectados por reabsorción radicular (incisivo central y/o premolares). Además en el caso de reabsorción de IL fue analizada la reabsorción tridimensionalmente a través de la ThreeDimensional Leeds Orthodontic Root Resorption Target Scale (3D-LORTS). La ICM en la muestra seleccionada tuvo una edad promedio de 12 años, una relación por sexo mujeres:hombres de 1,5:1, frecuentemente de tipo unilateral, en el lado derecho y una localización bucolingual palatina (64,1 %) por sobre la vestibular (35,9 %). La reabsorción radicular alcanzó un 35,9 %, de la cual un 27,6 % involucró a IL y un 8,3 % en dientes anexos adyacentes. En cuanto a la distribución tridimensional de la reabsorción radicular, la más frecuente involucró el tercio apical (60 %), con compromiso pulpar o severo (40 %), involucrando solo una cara, la palatina (54 %). Ninguna de las variables anteriores consideradas, demostró diferencias estadísticas con la reabsorción radicular de incisivos laterales.

ABSTRACT: One of the problems with greatest aesthetic and functional consequences in orthodontics is the Impaction of Maxillary Canines (ICM) being the main reason for root resorption of the adjacent teeth. Currently there are no studies describing root resorption by ICM through cone beam computed tomography (CBCT) in the Chilean population. The main objective of the study was to describe patients between 8 and 18 years old, who presented with ICM (or risk thereof), with the characteristics of canine impaction as well as root resorption presented in lateral incisors (IL) and in other adjacent teeth. In this retrospective study, 135 CBCT subjects were selected for convenience, of which 181 canines presented ICM. The variables were analyzed: age, sex, type of ICM (unilateral or bilateral), buccolingual location (vestibular or palatal), side of impaction (right or left), root resorption in the lateral incisor and registration of adjacent teeth affected by resorption radicular (central incisor and/or premolars). In addition, when reabsorption of IL was observed, three-dimensional analysis was made using the Three-Dimensional Leeds Orthodontic Root Resorption Target Scale (3D-LORTS). The ICM in the selected sample had an average age of 12 years, a ratio by sex of women:men of 1.5:1, frequently of unilateral type, on the right side and with palatine buccolingual location (64.1 %) above the vestibular (35.9 %). Root resorption reached 35.9 %, of which 27.6 % presented in the IL and 8.3 % in adjacent teeth. Regarding the three-dimensional distribution of root resorption, the most frequent involved the apical third (60 %), with pulpal or severe damage (40 %), in only one location, the palatine (54 %). None of the above variables considered showed statistical differences with the root resorption of lateral incisors.

Analysis of Estrogen Effects on Eruption of Rat Molars / Análisis de los Efectos del Estrógeno en la Erupción de Molares de Rata

ABSTRACT: Tooth eruption requires resorption of the alveolar bone interposed between the tooth germ and the oral mucosa (coronal bone). The cells responsible for bone resorption are the osteoclasts and their activity can be reduced or inactivated by estrogen hormone. We aimed to investigate the effects of estrogen on the process of tooth eruption in rats. Thirty-three Wistar rats, aged two-to-17-days, were divided into control, sham and estrogen-treated groups. After daily injections with estrogen, the animals were euthanized and the jaws removed and processed for histological analysis. We performed clinical examination, morphological analysis, quantification of the number of osteoclasts on the surface of the coronal bone and immunohistochemical analysis of estrogen receptor type alpha (ERα). Estrogen therapy was effective, which could be confirmed by the higher estrogen plasma levels on treated animals. However, it had no effect on tooth development or tooth eruption. Progressive bone resorption was observed and the number of osteoclasts on coronal bone was not affected on hormoneinjected animals, allowing tooth to erupt at the same time observed in untreated animals. Immunohistochemistry for ERα confirmed the presence of this type of receptor in osteoclasts, osteoblasts and osteocytes. Taken together, our results showed that estrogen stimulation was not sufficient to decrease the number of osteoclasts on the coronal bone, supporting the idea that, although estrogen may have a protective activity on bone resorption, this may not apply to the alveolar bone that is meant to be resorbed during eruptive process.

RESUMEN: La erupción dental requiere la resorción del hueso alveolar interpuesto entre el germen dental y la mucosa oral (hueso coronal). Las células responsables de la resorción ósea son los osteoclastos y su actividad puede reducirse o inactivarse por la hormona del estrógeno. Objetivos: apuntamos a investigar los efectos del estrógeno en el proceso de la erupción dental en ratas. Treinta y tres ratas Wistar, de dos a 17 días de edad, se dividieron en grupos de control, Sham y se trataron con estrógenos. Los animales fueron eutanizados después del tratamento con estrógeno y se procesaron las mandíbulas para el análisis histológico. Se realizó el examen clínico, el análisis morfológico, la cuantificación del número de osteoclastos en la superficie del hueso coronal y el análisis inmunohistoquímico del tipo de receptor de estrógeno alfa (ERα). La terapia de estrógeno fue eficaz, lo que podría ser confirmado por los niveles plasmáticos más altos de estrógeno en los animales tratados. Sin embargo, no se observó ningún efecto sobre el desarrollo de los dientes o la erupción dental. Se observó una resorción ósea progresiva y el número de osteoclastos en el hueso coronal no se vio afectado en los animales inyectados con hormonas, permitiendo que el diente erupcionó durante el mismo período de tiempo observado en animales no tratados. La inmunohistoquímica para el ERα confirmó la presencia de este tipo de receptor en los osteoclastos, osteoblastos y osteocitos. Nuestros resultados mostraron que la estimulación del estrógeno no fue suficiente para reducir el número de osteoclastos en el hueso coronal confirmando que, si bien el estrógeno puede tener una actividad protectora en la resorción ósea, esto puede no se aplica al hueso alveolar que está destinado a ser rerecurrido durante el proceso eruptivo.

Manifestaciones clínicas durante el brote dentario e influencia de la lactancia materna / Clinical manifestations during the dental outbreak and influence of breastfeeding

La lactancia materna es un acto fisiológico, instintivo de herencia biológica adaptativa que debe constituir el único alimento que el niño reciba durante los primeros seis meses de vida; es ideal para el desarrollo y el crecimiento pleno. La investigación tuvocomo objetivo de determinar las manifestaciones clínicas durante el brote dentario e influencia de la lactancia materna. Se realizó un estudio descriptivo transversal en el período de marzo de 2017 a enero de 2018, en pacientes que se encontraban en el brote de la dentición temporal de los consultorios 33 y 34 del área de salud de la Clínica Universitaria de Especialidades Estomatológicas Manuel Cedeño, el universo fue de 95 pacientes entre las edades de 3 meses a 3 años. Se encontraron como resultados que de 95 pacientes, 84 presentaron manifestaciones clínicas, las manifestaciones generales fue la más representativa con el 66,66 por ciento; el 61,05 por ciento de los niños no tuvo lactancia materna, existió una relación entre manifestaciones clínicas y lactancia materna con p= 0,0009. Se concluye que las manifestaciones generales son las más representativas durante el brote de la dentición temporal y una influencia de la no presencia de la lactancia materna en la aparición de las manifestaciones(AU)

Breastfeeding is a physiological, instinctive act of adaptive biological inheritance that should be the only food the child receives during the first six months of life; It is ideal for development and full growth. The objective of the research was to determine the clinical manifestations during the dental outbreak and the influence of breastfeeding. A cross-sectional descriptive study was carried out in the period from March 2017 to January 2018, in patients who were in the outbreak of the temporary dentition of the 33rd and 34th offices of the health area of the University Clinic of Stomatological Specialties Manuel Cedeño, the universe was 95 patients between the ages of 3 months to 3 years. Results were found that of 95 patients, 84 had clinical manifestations, the general manifestations were the most representative with 66.66 percent; 61.05 percent of the children did not have breastfeeding, there was a relationship between clinical manifestations and breastfeeding with p = 0.0009. It is concluded that the general manifestations are the most representative during the outbreak of the temporary dentition and an influence of the absence of breastfeeding in the appearance of the manifestations(EU)

Clinical and x-ray oral evaluation in patients with congenital Zika Virus

Abstract Objective: The aim of this study was to investigate possible malformations in the soft, bone and/or dental tissues in patients with congenital Zika Virus (ZIKV) by clinical and x-ray evaluation. Methodology: Thirty children born with ZIKV and 30 children born without ZIKV (control group) were included in the study. Patients were evaluated over 24 consecutive months according to the variables: sex, age, cleft palates, soft tissue lesions, alveolar ridge hyperplasia, short labial and lingual frenums, inadequate posture of the lingual and perioral muscles at rest, micrognathia, narrow palatine vaults, changes in the teeth shape and/or number, sequence eruption, spasms, seizures and eruption delay were evaluated. Chi-square test, Student's t-test and nominal logistic regression were used (p<0.05). Results: Among the 30 babies examined, the mean age of the first dental eruption was 10.8±3.8 with almost two-thirds of the children (n=18, 60%) experiencing eruptions of their first tooth after 9 months of age, nine children (30%) had inadequate lingual posture at rest, more than half of the children (n=18, 60%) had short labial or lingual frenums. ZIKV babies showed a high prevalence of clef palate (p<0.001), inadequate lingual posture at rest (p=0.004), micrognathia (p=0.002), changes in the shape and/or number of teeth (p=0.006), alteration in sequence of dental eruption (p<0.001) and muscles spasms (p=0.002). The delay eruption was associated with inadequate lingual posture at rest (p=0.047), micrognathia (p=0.002) and changes in the shape and/or number of teeth (p=0.021). The delayed eruption (p=0.006) and narrow palatine vaults (p=0.008) were independently associated with ZIKV. Moreover, female patients showed the most narrow palatine vaults (p=0.010). Conclusions: The children with ZIKV showed a greater tendency to have delayed eruption of the first deciduous tooth, inadequate lingual posture and short labial and lingual frenums.