Dental age estimation by assessing the pulp volume of five teeth in a peruvian population using cone beam computed tomography images / Estimación de la edad dental evaluando el volumen pulpar de cinco dientes utilizando imágenes de tomografías computarizadas de haz cónico en una población peruana

Abstract Dental age estimation is very important for individual identification in criminal and civil forensic investigations. One of the methods for age estimation is studying age related changes in pulp volume of teeth. The objective of the current study was to estimate dental age from the pulp volume of five different categories of teeth of a Peruvian sample using cone beam computed tomography (CBCT). Retrospective CBCT records of 231 patients (females (134), males (97), age: 12-60 years) were included in the study, categorized into five different age groups (12-19, 20-29, 30-39, 40-49, 50-59, 60 years and older). Dental pulp volume of five categories of teeth(upper canines, left upper central incisors, left upper first molars, lower left first premolars, first molars) were analyzed using Romexis® 5.3.3.5 software for each patient. There was a reduction in the pulp volume of upper right and left canine with age. The Pulp volume was lowest in people aged 60 years and over. Linear regression analysis of the pulp volume and chronological age showed a coefficient of determination of 30%, suggesting a weak correlation. A weak correlation between dental pulp and age is derived. But, a robust large homogenous sample of teeth in future for different age groups may establish a reliable regression equation.

Resumen La estimación de la edad dental en personas vivas y cadáveres es muy importante para la Odontología Forense, sobre todo en casos de identificación en investigaciones legales y sociales. El objetivo del estudio fue estimación de la edad dental mediante la medición del volumen pulpar de imágenes dentales en tomografía computarizada de haz cónico (TCHC) de pacientes peruanos. Fueron analizadas 231 TCHC de pacientes entre 12 a 60 años a más. (Mujeres (134), hombres (97)) se dividieron en seis grupos de edad (12-19, 20-29, 30-39, 40-49, 50-59, 60 años a más). El análisis volumétrico de la pulpa dental se realizó en un total de 1155 dientes (caninos superiores, incisivos centrales superiores izquierdos, primeros molares superiores izquierdos y primeros premolares inferiores izquierdos), mediante el software Romexis® 5.3.3.5. El análisis de regresión lineal mostró un coeficiente de determinación del 30% que sugiere una correlación débil entre la relación del volumen pulpar de los dientes y la edad. El volumen pulpar de los caninos superiores derecho e izquierdo disminuyó a medida que aumentaba la edad y el volumen pulpar en dientes de personas de 60 años a más fue el más bajo. Sin embargo, se pueden proponer estudios futuros para incluir una gran muestra homogénea de dientes en diferentes categorías y grupos de edad para confirmar la correlación y establecer una ecuación de regresión confiable.

Uso de dientes bovinos como elección para trabajos de investigación en odontología / The use of bovine teeth as a choice for dental investigation papers

Los dientes animales de las diferentes especies (hu- mano, equino, cerdo, etc.) están constituidos histológi- camente por cuatro tejidos fundamentales. Ellos son: esmalte, dentina, cemento y pulpa dental. Su compo- sición, estructura, morfología y tamaño son disímiles para cada género. Según numerosas investigaciones, los dientes de bovino serían los de elección por ser de fácil obtención y por tener muy pocas, o ninguna, diferencias tanto a nivel macro como microscópico con respecto a los dientes humanos. El objetivo de la presente revisión es aportar información actualizada acerca de las características histológicas de los tejidos dentarios bovinos y profundizar el conocimiento de las similitudes y diferencias de los dientes bovinos y humanos dando soporte a otros estudios compa- rativos y promoviendo la utilización de las piezas dentarias bovinas en trabajos de investigación en odontología (AU)

The animal teeth of the different species (human, equine, pig, etc.) are histologically constituted by four fundamental tissues: enamel, dentin, cement and dental pulp. Their composition, structure, morphology and size are dissimilar for each gender. According to numerous investigations, bovine teeth would be the ones of choice because they are easy to obtain and have very few or no differences, both at the macro and microscopic levels, with respect to human teeth. The objective of this review is to provide updated information about the histological characteristics of bovine dental tissues and deepen the knowledge of the similarities and differences between bovine and human teeth, supporting other comparative studies and promoting the use of bovine dental pieces in research work in dentistry (AU)

Tooth and pulp chamber automatic segmentation with artificial intelligence network and morphometry method in cone-beam CT / Segmentación automática de cámaras dentales y pulpares con red de inteligencia artificial y método de morfometría en TC de haz cónico

SUMMARY: This study aims to extract teeth and alveolar bone structures in CBCT images automatically, which is a key step in CBCT image analysis in the field of stomatology. In this study, semantic segmentation was used for automatic segmentation. Five marked classes of CBCT images were input for U-net neural network training. Tooth hard tissue (including enamel, dentin, and cementum), dental pulp cavity, cortical bone, cancellous bone, and other tissues were marked manually in each class. The output data were from different regions of interest. The network configuration and training parameters were optimized and adjusted according to the prediction effect. This method can be used to segment teeth and peripheral bone structures using CBCT. The time of the automatic segmentation process for each CBCT was less than 13 min. The Dice of the evaluation reference image was 98 %. The U-net model combined with the watershed method can effectively segment the teeth, pulp cavity, and cortical bone in CBCT images. It can provide morphological information for clinical treatment.

RESUMEN: El objetivo del presente estudio fue extraer estructuras dentarias y óseas alveolares desde imágenes CBCT automáticamente, lo cual es un paso clave en el análisis de imágenes CBCT en el campo de la estomatología. En este estudio, se utilizó la segmentación de tipo emántica para la segmentación automática. Se ingresaron cinco clases de imágenes CBCT marcadas, para el entrenamiento de la red neuronal U-net. El tejido duro del diente (incluidos esmalte, dentina y cemento), la cavidad de la pulpa dentaria, hueso cortical, hueso esponjoso y otros tejidos se marcaron manualmente en cada clase. Los datos se obtuvieron de diferentes regiones de interés. La configuración de la red y los parámetros de entrenamiento se optimizaron y ajustaron de acuerdo con un análisis predictivo. Este método se puede utilizar para segmentar dientes y estructuras óseas periféricas mediante CBCT. El tiempo del proceso de segmentación automática para cada CBCT fue menor a 13 min. El "Dice" de evaluación de la imagen de referencia fue de 98 %. El modelo U-net combinado con el método "watershed"puede segmentar eficazmente los dientes, la cavidad pulpar y el hueso cortical en imágenes CBCT. Puede proporcionar información morfológica para el tratamiento clínico.

The effect of high wear diets on the relative pulp volume of the lower molars.

OBJECTIVES: One role of dental pulp is in the upkeep and maintenance of dentine. Under wear, odontoblasts in the pulp deposit tertiary dentine to ensure the sensitive internal dental tissues are not exposed and vulnerable to infection. It follows that there may be an adaptive advantage for increasing molar pulp volume in anthropoid primate taxa that are prone to high levels of wear. The relative volume of dental pulp is therefore predicted to covary with dietary abrasiveness (in the sense of including foods that cause high degrees of wear). MATERIALS AND METHODS: We examined relatively unworn lower second molars in pairs of species of extant hominoids, cebids, and pitheciids that vary in the abrasiveness of their diet (n = 36). Using micro-CT scans, we measured the percent of tooth that is pulp (PTP) as the ratio of pulp volume to that of the total volume of the tooth. RESULTS: We found that in each pair of species, the taxa that consume a more abrasive diet had a significantly higher PTP than the closely related taxa that consume a softer diet. CONCLUSIONS: Our results point to an adaptive mechanism in the molars of taxa that consume abrasive diets and are thus subject to higher levels of wear. Our results provide additional understanding of the relationship between dental pulp and diet and may offer insight into the diet of extinct taxa such as Paranthropus boisei or into the adaptive context of the taurodont molars of Neanderthals.

Sex classification of first molar teeth in cone beam computed tomography images using data mining.

OBJECTIVE: The teeth have been used as a supplementary tool for sex differentiation as they are resistant to post-mortem degradation. The present study aimed to develop a new novel informatics framework for predicting sex from linear tooth dimension measurements achieved from cone beam computed tomography (CBCT) images. METHOD AND MATERIALS: A clinical workflow using different machine learning methods was employed to predict the sex in the present study. The CBCT images of 485 subjects (245 men and 240 women) were evaluated for sex differentiation. Nine parameters were measured in both buccolingual and mesiodistal aspects of the teeth. We applied our dataset to Naïve Bayesian (NB), Random Forest (RF), and Support Vector Machine (SVM) as classifiers for prediction. Genetic feature selection was used to discover real features associated with sex classification. RESULTS: The 10-fold cross-validation results indicated that NB had higher accuracy than SVM and RF for sex classification. The genetic algorithm (GA) indicated that the model could fit the data without using the enamel thickness and pulp height. The average classification accuracy of our clinical workflow was 92.31 %. CONCLUSION: The results showed that NB was the best method for sex classification. The application of the first molar teeth in sex prediction indicated an acceptable level of sexual classification. Therefore, these odontometric parameters can be applied as an additional tool for sex determination in forensic anthropology.

Estimación de edad mediante la relación área pulpa/diente en caninos mandibulares: estudio en una muestra chilena utilizando el Método de Cameriere / Dental age estimation by pulp/tooth ratio in mandibular canines: study in a Chilean sample by Camerierer's Method

La estimación de edad compone un aspecto importante en investigaciones forenses. Diferentes métodos se han descrito en odontología forense basadas en la correlación entre la edad y estructuras dentales. Cameriere et al. proponen un método cuantitativo para estimación de edad en adultos, a partir de la evaluación de la relación del área pulpa/diente, en base a la aposición de dentina secundaria. El objetivo del estudio fue desarrollar modelos de regresión para la estimación de edad dental mediante la relación área pulpa/diente en caninos inferiores en una muestra Chilena. Se analizaron 212 radiografías periapicales digitales (RPD) (86 hombres y 126 mujeres) de caninos mandibulares mediante el programa Image J para establecer el área de la pulpa y el diente. Se registraron los datos de sexo y edad de las RPD seleccionadas en forma ciega. Fueron desarrollados modelos de regresión lineal simples para la estimación de edad. El coeficiente de determinación para R33 fue 27,8 % y de 29,6 % para R44, con un error absoluto medio de 11,02 años y 10,37 años respectivamente. El análisis de ANOVA no mostró diferencias estadísticamente significativas para las relaciones área pulpa/diente de caninos según sexo (p> 0,05). Según los resultados obtenidos, la metodología propuesta por Cameriere et al. es fiable para estimar la edad dental mediante la relación área pulpa/diente en adultos. Sin embargo, en los modelos de regresión desarrollados para la población Chilena, se puede afirmar que el ajuste indicado por los coeficientes de determinación muestran incerteza entre las variables área pulpa/diente y edad cronológica en caninos inferiores, por lo tanto se sugiere considerar otros métodos adicionales para estimar edad en esta población.

Age estimation is an important aspect In forensic investigations. Different methods in forensic odontology based on the correlation between age estimation in adults, from the analysis of the pulp/tooth area, based on the apposition of secondary dentine. The aim of the study was to develop regression models for the dental age estimation by the relation pulp/tooth area, in lower canines in a Chilean sample, using digital peri-apical radiographs (DPR) applying Cameriere's method. We analyzed 212 DPR (86 males and 126 females) mandibular canines through Image J program to measure the pulp/tooth area. Age and sex information was obtained of the DPR's blindly selected. We developed simple linear regression models for age estimation. The coefficient of determination to R33 was R2 age and dental structures have been described. Cameriere et al. proposed a quantitative method for 27.8 % and R2 29.6 % to R44, with a mean absolute error of 11.02 years, to R33 and 10.37 years to R44. ANOVA analysis showed no statistically significant differences for the pulp/tooth relation area of canines according to sex (p> 0.05). According to the results, the Cameriere's et al., method is reliable for dental age estimation according to pulp/tooth ratio in adults. However, in the regression models developed for Chilean population, it can be stated that the adjustment indicated by the coefficients of determination, show uncertainty between the pulp / tooth area and chronological age in lower canines, therefore it is suggested to use additional estimation methods for age in this population.

Biodentine Induce Proteínas Apoptóticas Caspasa 3 y PARP-1 en Células de la Pulpa Dental Humana / Biodentine Induces Apoptotic Proteins Caspase 3 and PARP - 1 on Human Dental Pulp Cells

RESUMEN: Las patologías pulpares han sido un verdadero reto para la odontología principalmente por su tratamiento. Actualmente, existen numerosos biomateriales en el mercado que reportan tener propiedades inherentes en los tejidos dentarios. Sin embargo, diferentes estudios sobre múltiples líneas celulares expuestas a estos biomateriales demuestran resultados controversiales como biocompatiblidad y citotoxicidad celular. Biodentine, es un cemento endodóntico en base a silicatos cálcico de múltiples aplicaciones, que prestaría propiedades de biocompatibilidad como bioactividad celular, características que le permitirían incluso ser utilizado en contacto directo con la pulpa dental. El objetivo de este estudio es la evaluación in-vitro de Biodentine, sobre cultivos de células de la pulpa dental humana (CCPDH). Se prepararon discos de cemento de Biodentine™ de 2 x 6 mm, los que se expusieron a cultivos de células aisladas de la pulpa dental humana. Luego de 24, 48 y 72 horas de exposición, se realizaron ensayos de viabilidad celular utilizando el método colorimétrico MTT. También se realizaron ensayos de expresión proteica de dos proteínas involucradas en la vía de señalización de la apoptosis celular: Caspasa - 3 clivada y Poli (ADP-Ribosa) Polimerasa, PARP - 1. Existen diferencias estadísticamente significativas (p<0,05) en los ensayos de viabilidad celular entre las células expuestas a Biodentine y el grupo control, como también a medida que aumenta el tiempo de exposición (p<0,05). Por otra parte, también existen diferencias significativas (p<0,05) en la expresión de PARP- 1 en los grupos sometidos a Biodentine. Los resultados obtenidos en este estudio demuestran que Biodentine genera citotoxicidad celular en cultivos celulares de pulpa dental humana, por disminución de la viabilidad celular como por la expresión de proteínas apoptóticas. Es por esto que la utilización de este biomaterial debería ser estudiado y considerarse en cada caso clínico, especialmente como recubridor pulpar directo.

ABSTRACT: Oral pathologies have been a real challenge for dentistry, mainly due to its treatment. Currently, there are numerous biomaterials on the market that may present inherent properties in dental tissues. However, studies on multiple cell lines are based on biocompatible results such as biocompatibility and cellular cytotoxicity. Biodentine is endodontic cement based on calcium silicates of multiple applications, which would provide biocompatibility properties as cellular bioactivity, characteristics that will allow it to be used in direct contact with the dental pulp. The objective of this study is the in vitro evaluation of Biodentine, on cultures of cells of the human dental pulp (HDPC). Biodentine cement disks of 2 x 6 mm were prepared, and HDPC culture plates were introduced. After 24, 48 and 72 hours of exposure, cell viability tests were performed using the MTT colorimetric method. On the other hand, protein expression assays of two proteins involved in the signaling pathway of cell apoptosis Caspase-3 cleaved (cas-3 clv) and PARP-1 are carried out. There are statistically significant differences (p <0,05) in the cell viability tests between Biodentine and control group, as well as the exposure time increases (p <0,05). Otherwise, there are also significant differences (p <0,05) in the expression of PARP-1 in the groups, sometimes a Biodentine. The results in this study that Biodentine generates a cellular cytotoxicity in HDPC cultures, therefore, cell viability as the expression of apoptotic proteins. This is why the use of this biomaterial should be studied for each particular clinical case, especially as a direct pulp capping agent.

Age estimation by pulp/tooth area ratio in anterior teeth using cone-beam computed tomography: comparison of four teeth.

OBJECTIVES: Age estimation is one of the most important factors in forensic medicine. Measuring secondary dentin deposition using cone-beam computed tomography images is an easy and noninvasive method. The aim of this study was to evaluate cone-beam computed tomography images as a reliable method to estimate chronological age by pulp/teeth ratio in anterior teeth in Iranian population. METHODOLOGY: A total of 649 CBCT images from 377 Iranian patients aged between 20 and 69 years were evaluated. Pulp/teeth ratio (PTR) in maxillary and mandibular canine and central incisor teeth was measured in the axial and sagittal sections using OnDemand 3D Dental software. The Pearson correlation coefficient was determined to evaluate the correlation between the variables. Linear regression analysis, as well as age estimation formula, was used for each tooth separately. RESULTS: The regression analyses indicated that maxillary central incisors were more reliable for age estimation (R2=0.586 and standard error of estimate=7.045) compared with the other anterior teeth studied. Maxillary canine teeth had the lowest predictive power (R2=0.392 and standard error of estimate=8.387). Also, comparison of the axial and sagittal sections showed that the axial sections had a higher predictive power. (R2=0.48 for axial plans and R2=0.328 for sagittal plans). CONCLUSION: The use of cone-beam computed tomography in age estimation by pulp/teeth ratio of anterior teeth is useful and a reliable method for age estimation in Iranian population.

Application of the Kvaal method for age estimation using digital panoramic radiography of Chinese individuals.

The Kvaal method as a non-invasive method for age estimation based on the changes of pulpal size caused by secondary dentin deposition has been applied to different ethnics. However, its results are often conflicting and its accuracy is relatively poor. This study aimed to verify the applicability of the Kvaal method to estimate the ages of the Chinese population using digital panoramic radiographs and to formulate specific regression equations for use in Chinese subjects. A sample of 360 digital panoramic radiographs from northern Chinese population were selected, from which the pulpal size and width of six tooth types (maxillary central incisor, lateral incisor, second premolar, mandibular lateral incisor, canine, and first premolar) were measured using Kvaal's method. Then, inter- and intra-observer reliabilities were calculated to evaluate the reproducibility of those measurements. The correlation between chronological age and measurements was also examined and the Chinese-specific equations for age estimation were conducted. After comparing the accuracy of the Chinese-specific equation with the original Kvaal equation, the age of the Chinese population was clearly overestimated by Kvaal's equation, and a Chinese-specific equation could ameliorate age prediction accuracy. In addition, the residuals of the Chinese-specific equation were significantly lower than that of the original Kvaal's method. Thus, we concluded that the original Kvaal equation cannot accurately estimate age in the Chinese population. Although accuracy improved using the Chinese-specific equation that was based on Kvaal's methodology, the standard deviation remained large. In view of the lack of accurate age estimation methods for adults, we propose finding more correlated variables or combining other age estimation methods to increase the accuracy for adult age estimation.

Morphometric study on single-root premolars in a European population sample: an update on lengths and diameters

External dental root morphology knowledge is fundamental for the implication in periodontal and implant dentistry branches. So far the literature available presents a few and not updated studies regarding this particular topic. The aim of this study is to investigate the morphometry of external gross anatomy of single-rooted premolars, focusing on length and tapering parameters. One hundred seventy four extracted teeth of European origin were used to measure the root length and diameter on the 4 radicular surfaces, starting from the cement- enamel junction to the root apex. Data were statistically analyzed with descriptive measures and any statistical significance (p value <0.05) was evaluated by means of T-student test. The length of the single-root mandibular and maxillary premolars resulted to be higher than those reported in literature. The data regarding the tapering showed a pronounced lowering of the diameter root from the middle point of the root. In addition, the single-rooted premolar showed to own an oval-shaped root characterized, in both arches, by a high variability, confirming the data reported in literature. The present morphometric study providing analytical data regarding the length, the tapering and the high variability of the single-root premolar highlights the need of an accurate knowledge of the root anatomy for a correct therapeutic approach in the daily clinical practice

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Dental age estimation in Malaysian adults based on volumetric analysis of pulp/tooth ratio using CBCT data.

Forensic odontology plays an important role in human identification and dental age estimation is an integral part of this process. The aim of the study was to investigate the association between chronological age and pulp/tooth volume ratio in a Malaysian population (Malays and Chinese) from cone-beam computed tomography (CBCT) scans, enhanced with Mimics software. Three hundred CBCT scans of 153 males and 147 females, aged between 16 and 65 years were divided into 5 age groups. Volumetric analysis of the pulp/tooth ratio was performed in maxillary left canines, maxillary right canines and maxillary right central incisors. Simple linear regression and Pearson correlation analysis indicated the strongest coefficient of correlation (R) values for maxillary right central incisors (0.83) followed by maxillary right canines (0.74) and maxillary left canines (0.73). Fisher's Z test indicated that dental age estimation is gender independent. The derived regression equations were further validated on an independent group of 126 teeth. The results indicated mean absolute error (MAE) values of 6.48 and 8.58 years for maxillary right central incisors and maxillary canines respectively. It was also noticed that MAE values were higher among the age groups ranging from 46 to 65 years. This study showed that a volumetric change in the pulp cavity with age is a valuable assessment method for dental age estimation among Malaysian population.

Age estimation by pulp/tooth area ratio in anterior teeth using cone-beam computed tomography: comparison of four teeth

Abstract Objectives Age estimation is one of the most important factors in forensic medicine. Measuring secondary dentin deposition using cone-beam computed tomography images is an easy and noninvasive method. The aim of this study was to evaluate cone-beam computed tomography images as a reliable method to estimate chronological age by pulp/teeth ratio in anterior teeth in Iranian population. Methodology A total of 649 CBCT images from 377 Iranian patients aged between 20 and 69 years were evaluated. Pulp/teeth ratio (PTR) in maxillary and mandibular canine and central incisor teeth was measured in the axial and sagittal sections using OnDemand 3D Dental software. The Pearson correlation coefficient was determined to evaluate the correlation between the variables. Linear regression analysis, as well as age estimation formula, was used for each tooth separately. Results The regression analyses indicated that maxillary central incisors were more reliable for age estimation (R2=0.586 and standard error of estimate=7.045) compared with the other anterior teeth studied. Maxillary canine teeth had the lowest predictive power (R2=0.392 and standard error of estimate=8.387). Also, comparison of the axial and sagittal sections showed that the axial sections had a higher predictive power. (R2=0.48 for axial plans and R2=0.328 for sagittal plans) Conclusion The use of cone-beam computed tomography in age estimation by pulp/teeth ratio of anterior teeth is useful and a reliable method for age estimation in Iranian population.

Effect of Residual Dental Pulp Tissue on Regeneration of Dentin-pulp Complex: An In Vivo Investigation.

INTRODUCTION: Current pulp revascularization procedures in teeth with necrotic pulps and open apices have produced histologic evidence of connective tissue growth, cementum, and bone within the root canals of experimental animals. This study aims to investigate the effect of maintaining uninflamed residual apical pulp tissue on the histologic outcome of pulp-dentin complex regeneration after a revascularization procedure in immature ferret cuspid teeth. METHODS: Twenty-eight cuspid teeth from 7 young male ferrets were used in this experiment. Seven teeth were reserved to serve as positive control samples without any treatment. In another 7 teeth, the pulp was completely extirpated (negative control), whereas the pulp of the remaining 14 teeth were removed to either 1-2 mm short of the apex (7 samples) or 2-4 mm short of the apex (7 samples). Blood clots were covered with mineral trioxide aggregate at the cementoenamel junction level of each tooth. Three months later, block sections were removed for histologic evaluations, and the data were statistically analyzed with the chi-square test (P < .05). RESULTS: All teeth with complete pulp extirpation showed the presence of bone inside the root canal. In contrast, the root canals for most teeth with pulp amputation 1-4 mm from the radiographic apex were filled with normal pulp, which extended coronally to the mineral trioxide aggregate, where hard tissue bridges had formed. CONCLUSIONS: Based on these results, we concluded that regeneration of the pulp-dentin complex is possible when the apical 1-4 mm of the apical pulp remains intact in immature teeth.

Anatomy of equine incisors: Pulp horns and subocclusal dentine thickness.

BACKGROUND: Equine incisors are often reduced in height during corrective dental procedures. Increased knowledge of subocclusal dentine thickness and pulp morphology may help prevent iatrogenic pulpar exposure. Although such data exist for equine cheek teeth, there are currently no reliable data for incisors. OBJECTIVES: To measure the distances between pulp cavities and the occlusal as well as the labial surfaces of equine incisors and to test if these distances change with age. Furthermore, pulp morphology with regard to number and orientation of pulp horns was investigated. STUDY DESIGN: Observational study using cadaver material and high-resolution computed tomography. METHODS: Upper and lower incisor arcades were removed from heads of 13 horses and scanned with high-resolution computed tomography. 3D Models were reconstructed and configuration as well as number of the pulp horns was evaluated. Anatomical marker points were set to measure distances between the pulp horn tips and the labial and occlusal surfaces. RESULTS: Subocclusal dentine thickness ranged between 1.5 and 11.7 mm in upper and 0.7 and 6.7 mm in lower incisors. It decreased with tooth age. Distance to labial aspect ranged between 3.5 and 9.0 mm in upper and 3.8 and 8.1 mm in lower incisors and increased with tooth age. MAIN LIMITATIONS: Details of horse management, feeding and previous dental care were not available. Therefore, it remains unknown how these factors influenced the results. CONCLUSIONS: Although mean subocclusal dentine thickness of greater than 4.1 mm was found, equine incisors occasionally have less than 1 mm of thickness with potential for iatrogenic pulpar exposure during incisor reduction. Therefore, great care should be exercised by any practitioner during incisor reduction.

Endodontium - together or separately?

Endodontium, otherwise referred to as pulp-dentin complex or endodont. This term includes two tooth tissues: dentin and pulp, which constitute a structural and functional unity. These tissues have a huge, inseparable influence on each other - the pulp (inter alia) nourishes the dentine, while the dentin forms a protective barrier for the pulp. They develop from the papillary tissue (Latin: papilladentis) from mesenchymal tissue. Nevertheless, in clinical practice this structural-functional complex is often treated as two separate tissues, and not as a whole. Adequate knowledge of the structure, function and protective mechanisms of the endodontium produces successful results in the treatment. The appropriate choice and application of the therapeutic methods and materials to the dentin secures vitality of both tissues of this complex.

Análise das alterações pulpares após expansão rápida da maxila em ratos / Analysis of pulpal changes after rapid maxillary expansion in rats

O objetivo deste estudo foi avaliar os efeitos da expansão rápida da maxila (ERM) na polpa dentária de dentes de ancoragem de ratos jovens, através das análises histomorfológica, histomorfométrica e de expressão gênica. Oitenta (n=80) ratos Wistar machos foram distribuídos aleatoriamente em 2 grupos: Grupo Controle (GC, n=40), em que os animais não tiveram ERM e foram sacrificados nos períodos de 3, 7, 14 e 21 dias após o início do experimento; e Grupo Experimental (GE, n=40), cujos animais foram submetidos à ERM e sacrificados nos mesmos períodos do Grupo Controle. As polpas dentárias dos incisivos superiores de 20 animais (n=20) de cada grupo, GC e GE, foram extraídas para a análise da expressão gênica do RNAm, pela técnica de Reação em Cadeia da Polimerase em Tempo Real (RT-PCR), para os genes Fator de Crescimento Endotelial Vascular (Vegf), Sialofosfoproteína da Dentina (Dspp) e Ciclooxigenase-2 (Cox-2), e de 20 animais (n=20) para as análises histomorfológica e histomorfométrica do tecido pulpar. Todos os grupos que sofreram ERM apresentaram sinais da ocorrência de inflamação e aumento da densidade de vasos sanguíneos, com alterações transitórias na camada de odontoblastos. Houve aumento significativo da expressão gênica de Vegf em todos os períodos experimentais, sendo para Cox-2 apenas nos períodos de 3 e 7 dias, e para Dspp no 7º e 14º dias. Concluise que a ERM induziu a remodelação do tecido pulpar, com modulação transitória das expressões gênicas analisadas e da vascularização. (AU)

The objective of this study was to evaluate the effects of rapid maxillary expansion (RME) on the dental pulp of anchoring teeth of young rats through histolomorphological, histomorphometric and gene expression analyzes. Eighty (n= 80) male Wistar rats were randomly assigned to 2 groups: Control Group (CG, n=40), in which the animals had no ERM and were sacrificed at 3, 7, 14 and 21 days after initiation of the experiment; and Experimental Group (GE, n=40), whose animals were submitted to RME and sacrificed in the same periods of the GC. The dental pulps of the upper incisors of twenty animals (n=20) from each group, GC and GE, were extracted for analysis of the mRNA gene expression by the Reverse Transcription Polymerase Chain Reaction (RT-PCR) technique for the Vascular Endothelial Growth Factor (Vegf), Dentin Sialophosphoprotein (Dspp) and Cyclooxygenase-2 (Cox-2) genes, and twenty animals (n=20) for the histolomorphological and histomorphometric analyzes of the pulp tissue. All groups that suffered RME showed signs of inflammation occurrence and increased blood vessel density, with transient changes in the odontoblast layer. There was a significant increase in Vegf gene expression in all experimental periods, being for Cox-2 only in periods of 3 and 7 days, and for Dspp in the 7th and 14th days. It was concluded that ERM induced remodeling of pulp tissue, with transient modulation of the analyzed gene expression and vascularization. (AU)

Histological Evaluation of the Effect of Platelet-rich Plasma on Pulp Regeneration in Nonvital Open Apex Teeth: An Animal Study.

AIM: Platelet-rich plasma (PRP), which is a concentration of growth factors found in platelets, may be a suitable material for pulp regeneration. The aim of this animal study was a histological evaluation of PRP on pulp regeneration in nonvital teeth with immature apices. MATERIALS AND METHODS: A total of 40 premolar dogs' teeth were chosen for this study. After general anesthesia, the teeth were exposed, and subsequently, pulps were removed and the cavities were opened to the oral cavity. After 2 weeks, root canals were irrigated and disinfected with sodium hypochlorite with noninstrumentation technique, and triple antibiotic paste was placed inside the canals. Cavities were sealed with a temporary restoration. About 4 weeks later, canals were irrigated again and the teeth were randomly divided into three groups. Bleeding was evoked with overinstrumentation, then experimental materials for each group [PRP, mineral trioxide aggregate (MTA), and parafilm respectively] were placed over the bleeding, and orifices were sealed with MTA and glass ionomer. After 3 months, dogs were sacrificed and the teeth were separated from the jaws and sections prepared for histological evaluation. RESULTS: Regeneration was shown in 44.7% of the samples. About 47.3% of the samples in the MTA group and 42.1% of the samples in the PRP group showed regeneration; however, no regeneration was observed in the parafilm group. Chi-square test showed no significant difference between groups I and II. The soft regenerative tissue included pulp-like tissue and vessels. Mineralized regenerative tissue included cementum-like, periodontal ligament-like, and bone-like tissues. No normal pulp and nerve tissue were observed. CONCLUSION: Both PRP and MTA may be ideal scaffolds to accelerate the regeneration process. CLINICAL SIGNIFICANCE: Pulp repair in immature permanent teeth with weak roots has a better outcome than replacement of the pulp with gutta-percha or biomaterials.

Radiographic, Histologic, and Biomechanical Evaluation of Combined Application of Platelet-rich Fibrin with Blood Clot in Regenerative Endodontics.

INTRODUCTION: No in vivo study has been reported on the mechanical reinforcement of a tooth after regenerative endodontic treatment (RET). The present work aimed to evaluate the concurrent use of platelet-rich fibrin (PRF) with a blood clot (BC) in RET concerning periapical healing, root development, and tooth structural reinforcement. METHODS: In our study, 24 premolars from 3 beagle dogs were assigned into control, BC, and PRF + BC groups. Periapical healing was monitored with quantitative measurements of root elongation and thickening radiographically. Tooth biomechanical integrity was assessed with the fracture resistance test. Histologic evaluation was conducted. RESULTS: There was a significant difference among the periapical radiolucency decreasing rate of the control (43.75%) and the BC (100%) and PRF + BC (100%) groups (P < .05). The increase of root length and thickness in both the BC and PRF + BC groups was significantly greater than that in the control group (P < .05). No significant difference was detected between the 2 experimental groups regarding periapical healing or root development (P > .05). Teeth in the BC (249.3 ± 64.1 N) and PRF + BC (281.7 ± 37.8 N) groups had significantly higher fracture resistance than those in the control group (108.5 ± 23.3 N) (P < .05). No significant difference was revealed between the BC and PRF + BC groups (P > .05). Histologic evidence of cementumlike tissue deposition along the canal wall with scattered bonelike tissue in the canal was observed. CONCLUSIONS: Either a combination of PRF with BC or BC alone could improve periapical healing, induce root development, and reinforce tooth structure. No additional benefit of PRF to BC in RET was found.

Morphologic Change of Parvalbumin-positive Myelinated Axons in the Human Dental Pulp.

INTRODUCTION: Information on the nerve fibers innervating the dental pulp is crucial for understanding dental pain and hypersensitivity. This study investigated the morphologic differences of parvalbumin (PV)-positive (+) myelinated fibers in 3 different regions of the human dental pulp. METHODS: Light and electron microscopic immunohistochemistry for parvalbumin, a marker for myelinated fibers, and quantitative analysis were performed in the apical root, core of coronal pulp, and peripheral pulp of human premolar teeth. RESULTS: About 40% of the myelinated fibers in the apical root pulp became unmyelinated in the core of the coronal pulp, and virtually all the remaining fibers became unmyelinated at the peripheral pulp. The size of myelinated axons decreased from root to peripheral pulp. PV+ axons showed extensive axonal varicosities in the peripheral pulp. CONCLUSIONS: These findings suggest that the myelinated fibers innervating the human dental pulp undergo extensive morphologic change in the extrapulpal region and in the coronal and peripheral pulp, and that PV-mediated regulation of calcium concentration and its downstream events may occur primarily in axonal varicosities in the peripheral pulp.

Age-related morphological, histological and functional changes in teeth.

Throughout lifetime, the teeth are continuously exposed to numerous chemical and physical impacts, which cause the wear of the dental hard tissues, gingival recession and other oral changes with sometimes subsequent problems. Age-related wear of tooth surfaces reduces the dental enamel thickness and exposes deeper layers of enamel, which have different physical and chemical properties than the surface enamel. Gingival recession is the main causal factor of root caries and dentine hypersensitivity. Age-related changes in dentine include the formation of secondary dentine and the reduction in tubular lumen diameter (dentine sclerosis), which lead to a reduction in the volume of the pulp chamber. In addition to the reduction in the volume of pulp chamber, changes to the dental pulp also include dental pulp calcifications. The age-related physiological changes to the teeth should be carefully distinguished from pathological changes, especially when they induce pain or a negative impact on the oral health-related quality of life (OHRQoL) of the older individuals. Therefore, regular oral examinations coupled with early preventive measures should aim at maintaining oral health until old age.