Limitaciones Técnicas del Método de Conteo de Anulaciones del Cemento para Estimación de Edad. Hallazgos a Partir de Una Revisión con Búsqueda Sistemática / Technical Limitations of Cementum Annulation Count Method for age Estimation. Findings From A Scoping Review

En la última década, la odontología forense se ha enfocado en el desarrollo de metodologías para la estimación de edad (EE) debido a la gran demanda en procesos identificatorios. Entre esas técnicas, el conteo de anulaciones del cemento dental (TCA) ha ofrecido resultados promisorios, pero también contradictorios que han generado dudas sobre su precisión y confiabilidad. El objetivo de este trabajo fue caracterizar, establecer alcances, e identificar las limitaciones del conteo de TCA según los actuales estándares normativos y metodológicos. Se realizó una revisión con búsqueda sistemática del método de conteo de TCA para EE incluyendo estudios experimentales y notas técnicas en las bases PubMed/Medline, Scopus, Web of Science (WoS) y Embase. Se emplearon los términos "estimation", "age" y "cementum", con búsqueda manual complementaria en Google Scholar. Se excluyeron revisiones, estudios en colecciones arqueológicas, estudios radiológicos y cartas al editor. La búsqueda arrojó un total de 273 artículos, seleccionándose 27 que cumplieron con los criterios de inclusión. La mayoría de los estudios fueron publicados en Asia, particularmente en India (n=21). Sólo 6 artículos declararon el número total de individuos, tipos de diente y de cortes histológicos, siendo el premolar el más estudiado. Apenas dos artículos evaluaron la calidad de la muestra a analizar mediante legibilidad de los cortes obtenidos. El test más empleado para evaluar la precisión del método fue el coeficiente de correlación de Pearson (n=21). Estos hallazgos exponen la alta heterogeneidad reportada en las metodologías de EE mediante conteo por TCA, por lo que aún no existe un proceso estandarizado que abarque todas sus etapas y entregue resultados confiables siguiendo los estándares jurídicos actuales para la evidencia científica. Un mayor control de las limitaciones técnicas detectadas aumentará el valor como prueba en un contexto identificatorio legal o forense.

SUMMARY: In the last decade, forensic odontology has focused on the development of age estimation (AE) methodologies due to the great request in identification processes. Among these techniques, the tooth cementum annulation (TCA) count method has offered promising but also contradictory results, raising questions about its accuracy and reliability. The aim of this work was to characterize, establish the scope, and identify the limitations of the TCA count method according to the current normative and methodological standards. A scoping review was carried out for TCA count methods for AE, including experimental studies and technical notes in the PubMed/Medline, Scopus, Web of Science (WoS) and Embase databases. The terms "estimation", "age" and "cementum" were used, with a complementary manual search in Google Scholar. Reviews, studies in archaeological collections, radiological studies and letters to the editor were excluded. The search yielded a total of 273 articles, selecting 27 of them that met the inclusion criteria. Most of the studies were published in Asia, particularly India (n=21). Only 6 articles declared the total number of individuals, types of teeth, and histological sections, with the premolar being the most studied. Only two articles evaluated the quality of the sample to be analyzed through the legibility of the cuts obtained. The most widely used test to assess the precision of the method was the Pearson correlation coefficient (n=21). These findings expose the high heterogeneity reported in EE methodologies by counting TCA, so there is still no standardized process that covers in all its stages and delivers reliable results following current legal standards for scientific evidence. More control of the detected technical limitations will increase the value as evidence in a legal or forensic identification context.

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)

Using histological staining techniques to improve visualization and interpretability of tooth cementum annulation analysis / Uso de técnicas de tinción histológica para mejorar la visualización y la interpretación del análisis de la anulación del cemento dental

SUMMARY: The aim of the present study was to evaluate the effect of different staining techniques on applicability and accuracy of tooth cementum annulation (TCA) method. Nine decalcination techniques, 8 dehydration protocols and 8 different techniques were applied in 3 teeth from the persons of a known age. Black and white, and color images of histological sections were captured. An x- ray was taken of each tooth and they were photographed. Researchers were asked to observe both black/white and color images of histological sections. Researchers were divided into two groups. The first group analyzed histological images only, and the second group had photos of teeth and X-rays. In the first group of observers (without X ray) the differences in age estimation between real and observed age were significant for 2 younger patients, but not for the oldest patient, where the observed and real values matched. Of the 6 raters, the assesments of the last 3 (that used x-ray images together with histological sections) did not differ significantly from the real values. Extensive analysis and multiple repetitions performed in the present investigation revealed that the most optimal method of decalcification for TCA method was EDTA II for a period longer than 14 days at a section thickness of 2-3mm, while the most optimal protocol for dehydration was number IV. When it comes to staining, the most optimal staining protocol used for the cemental lines visualization and counting was Crocein Scarlet/Acid Fuchsin staining and Toluidine blue staining used at semithin section. Additional use of preexperimental evaluation employing x-ray of analyzed teeth decreased the errors of age estimation.

RESUMEN: El objetivo del presente estudio fue evaluar el efecto de diferentes técnicas de tinción sobre la aplicación y precisión del método de anulación de cemento dental (TCA). Se usaron nueve técnicas de descalcinación, 8 protocolos de deshidratación y 8 técnicas diferentes en 3 dientes de personas de edad conocida. Se capturaron imágenes en blanco y negro y en color de cortes histológicos. Se tomó una radiografía de cada diente y se fotografiaron. Los investigadores observaron las imágenes en blanco y negro y en color de las secciones histológicas. Los investigadores se dividieron en dos grupos; el primer grupo analizó solo imágenes histológicas y el segundo grupo tenía fotografías de los dientes y las radiografías. En el primer grupo de observadores (sin rayos X) las diferencias en la estimación de la edad entre la edad real y la edad observada fueron significativas para 2 pacientes más jóvenes, pero no para el paciente de mayor edad, donde los valores observados y reales coincidieron. De los 6 evaluadores, las valoraciones de los 3 últimos (que utilizaron imágenes de rayos X junto con cortes histológicos) no difirieron significativamente de los valores reales. El análisis exhaustivo y las múltiples repeticiones realizadas en la presente investigación revelaron que el método de descalcificación más óptimo para el método TCA fue EDTA II durante un período superior a 14 días con un grosor de sección de 2-3 mm, mientras que el protocolo óptimo para la deshidratación fue el número IV. En lo que respecta a la tinción, el protocolo de tinción más óptimo utilizado para la visualización y el recuento de las líneas de cemento fue la tinción con croceína escarlata / fucsina ácida y la tinción con azul de toluidina utilizada en la sección semifina. El uso adicional de la evaluación pre-experimental que emplea los rayos X de los dientes analizados disminuyó los errores de estimación de la edad.

Cemento dental: aspectos atuais de interesse para o clínico / Dental cementum: current aspects to the clinicians

Embora tenha havido avanço no entendimento da homeostase do cemento dental, o papel deste tecido e sua biologia permanecem não completamente elucidados. Este estudo buscou fornecer informações sobre os conhecimentos mais recente relacionados à biologia do cemento dental, com o objetivo de discutir o papel exercido por este tecido em condições não fisiológicas nos tecidos periodontais. Devido aos avanços na exploração do tecido ósseo, que compartilha diversas características similares, a pesquisa abrangente sobre o cemento dental tem sido encorajada, a fim de esclarecer a função completa deste tecido na homeostase periodontal e regeneração. Desta forma, no presente trabalho, sempre que possível será feito um paralelo entre osso alveolar e cemento dental. O desenvolvimento de metodologias e técnicas celulares e moleculares avançadas possibilitou um melhor entendimento do comportamento do cemento em situações diversas, como quando em situações patológicas, como a doença periodontal, e até mesmo frente à regeneração tecidual. Ademais, estudos clínicos e em modelo animal demonstraram resultados em relação à formação de cemento em abordagens regenerativas. No entanto, sugere-se que estudos posteriores possam contribuir para um melhor conhecimento sobre o cemento e o perfil celular dos cementoblastos e cementócitos, bem como suas interações para fornecer novos insights para o desenvolvimento de terapias eficientes e mais previsíveis para regeneração dos tecidos periodontais. Apesar dos avanços dos estudos clínicos e laboratoriais, pôde-se concluir que inúmeras questões referentes à biologia do cemento permanecem não esclarecidas.

Although some progress has been made to understand dental cementum homeostasis, its role and biology remains not completely elucidated. This study aimed to provide information on the recent knowledge related to the dental cementum biology, in order to discuss the role of this tissue in physiological and non-physiological conditions in the periodontal tissues. Due to advances in the exploration of bone tissue, which shares several similar features, comprehensive research on dental cementum has been encouraged in order to clarify the complete function of this tissue in periodontal homeostasis and regenerative approach. Novel methodologies and advanced cellular and molecular techniques provided better understanding of cementum in different circumstances, as pathological situations such as periodontal disease and even tissue regeneration. In addition, clinical and animal model designs show positive outcomes to cementum formation in regenerative approaches, however, it is suggested that further studies may contribute to better understand cementum tissue and cementoblasts and cementocytes profile, as well as their interactions, providing new insights to develop efficient and more predictable therapies for periodontal tissue regeneration. Despite advances in clinical and laboratory studies, it can be concluded that many questions regarding the cementum biology remain unclear.

Morphology of the cement-enamel junction (CEJ), clinical correlations / Morfología de la unión amelo-cementaria (UAC), correlaciones clínicas

The following study describes the mineralized tissue distribution which composes the cement-enamel junction, in a simple of Chilean people, comparing several teeth surfaces. Cervical area was observed (M-V, D-V, M-L/P, D-L/P sites) from 136 (n=68) longitudinal sections on premolars and incisors, with orthodontic or prosthetic reasons for exodontia, which were analyzed by optical microscope in order to identify the type of cement-enamel junction. For that measurement it was Choquet's criteria, founding four types: 1) cement over enamel, 2) enamel over cement, 3) vis a vis, 4) Gap presence between enamel, cement and exposed dentin. The objective of this study was to determine the prevalence of these. As result, it was observed that there was no association between tooth surface and Choquet's classification; however that association was observed while comparing the type of tooth and the relationship with mineralized tissues at the CEJ. So, incisors were associated with class 1 and premolars with class 3 of Choquet. Class 3 prevalence is the most frequently observed in the sample size (51.9 percent), following class 1 (42.4 percent), class 4 (4.4 percent), and class 2 with the lower prevalence on the sample (1.5 percent). Because this region is fragile and highly susceptible to pathological changes and from the external environment, it must be carefully handled during clinical procedures such as teeth whitening, orthodontics, restorations, root scaling and clamp placement.

Se describe la distribución de los tejidos mineralizados que componen la unión amelocementaria de una muestra de la población chilena, con respecto a distintos dientes y distintas caras de éste. Se observó la región cervical (zona M-V, D-V, M-L/P, D- L/P) de 136 (n=68) secciones longitudinales de premolares e incisivos, con indicación de extracción por razones ortodónticas o protésica, los cuales fueron analizadas mediante lupa estereoscópica para identificar el tipo de relación cemento-esmalte. Fue utilizada para dicha observación los criterios de Choquet; así se observaron cuatro tipos: 1) Cemento sobre esmalte; 2) Esmalte sobre cemento; 3) Bis a bis y 4) Presencia de brecha entre el esmalte y cemento con la dentina expuesta. Se observó que no existía asociación entre caras del diente y la clasificación de Choquet, en cambio sí existió dicha asociación entre el tipo de diente y la relación de los tejidos mineralizados en la UAC. De esta manera, los incisivos se asocian con la clase 1 y los premolares con la clase 3 de Choquet. En cuanto a la prevalencia, la clase 3 era la más frecuente en el total de la muestra (51,9 por ciento) seguido de la clase 1 (42,2 por ciento), de la clase 4 (4,4 por ciento) y la clase 2 fue observada en una pequeña proporción de la muestra (1,5 por ciento). Debido a que esta región es frágil y altamente susceptible a cambios patológicos y del medio externo debe ser manejada cuidadosamente durante procedimientos clínicos como el blanqueamiento dental, tratamiento de ortodoncia, restauración, destartraje o colocación de clamps.

Raíces dentales humanas normales y con perlas de cemento: comparación histológica de estructuras / Normal human dental roots and withcementum pearls: structural histological comparison

Durante la vida del diente en boca se deposita cemento celular en el ápice a fin de compensar el desgaste oclusal considerado normal. Al extraer un diente, en raras ocasiones es posible visualizar excesos de cemento con forma de perlas bien delimitados y duros al tacto, ubicados en otro sector radicular diferente al ápice. Nuestro objetivo fue comparar estructuras en ambos tipos de cemento a fin de hallar diferencias histológicas. Se utilizaron 20 dientes permanentes con perlas (G1) y 20 con raíces normales (G2). Las raíces de G1 se cortaron con disco metálico de grano fino a baja velocidad en sentido transversal, a la altura de la parte más prominente de la protuberancia, las raíces de G2 se marcaron en tercios y se cortaron en sentido transversal aproximadamente a la altura de la mitad del tercio apical y de ambos grupos se obtuvieron un segmento que fue reservado y otro que fue preparado con técnica por desgaste para visualización con MO a menor y mayor aumentos. Los resultados se compararon con prueba t de student, las variables categóricas se compararon con pruebas de Fisher significación 5 por ciento. Se obtuvieron 40 dientes de pacientes adultos, 42,5 por ciento masculinos y 57,5 por ciento femeninos, edad promedio 61+/-16 en G1 y 55+/-18 en G2 (p=0,289). El contorno exterior de las perlas fue liso, conservando su perímetro, la zona granular de Tomes fue visible al igual que las lagunas, que fueron menos abundantes, de mayor tamaño y con distribución desordenada llegando en menor proporción al borde del tejido comparado con cemento normal.

During tooth life in mouth cellular cement settles in the apex in order to compensate the occlusal wear considered normal. After a tooth extraction, on rare occasions it is possible to visualize cement excesses with pearls form well delimited and hard to tact, located in another radicular sector different of the apex. Our aim was to compare structures in both types of cement in order to find histological differences. Consequently, 20 permanent teeth with pearls (G1) and 20 with normal roots (G2) were used. G1 roots were cut by a thin grain metallic disc at low speed in transverse sense, at the height of the protuberance most prominent part; G2 roots were marked in thirds and cut in transverse sense at the half of the third apical. From both groups a segment was obtained to be reserved and other one that was prepared by erosion technology to be visualized by MO at minor and major increases. Results were compared with student t test, categorical variables with Fisher's tests significance 5 percent. Forty adult patients teeth were obtained, male 42.5 percent and female 57.5 percent, age average in G1 61+/-16 and 55+/-18 in G2 (p=0.289). Pearls exterior face was smooth, with a preserved perimeter, Tomes granular zone was visible as were lagoons, which were less abundant, greater in size and with uneven distribution arriving at tissue border in a lesser proportion compared with normal cement.

Influence of apical foramen lateral opening and file size on cemental canal instrumentation

Since instrumentation of the apical foramen has been suggested for cleaning and disinfection of the cemental canal, selection of the file size and position of the apical foramen have challenging steps. This study analyzed the influence of apical foramen lateral opening and file size can exert on cemental canal instrumentation. Thirty-four human maxillary central incisors were divided in two groups: Group 1 (n=17), without flaring, and Group 2 (n=17), with flaring with LA Axxess burs. K-files of increasing diameters were progressively inserted into the canal until binding at the apical foramen was achieved and tips were visible and bonded with ethyl cyanoacrylate adhesive. Roots/files set were cross-sectioned 5 mm from the apex. Apices were examined by scanning electron microscopy at ×140 and digital images were captured. Data were analyzed statistically by Student’s t test and Fisher’s exact test at 5% significance level. SEM micrographs showed that 19 (56%) apical foramina emerged laterally to the root apex, whereas 15 (44%) coincided with it. Significantly more difficulty to reach the apical foramen was noted in Group 2. Results suggest that the larger the foraminal file size, the more difficult the apical foramen instrumentation may be in laterally emerged cemental canals.

Tendo em vista que a instrumentação do forame apical tem sido sugerida para a limpeza e desinfecção do canal cementário, a seleção do calibre do instrumento e a posição do forame apical representam passos desafiantes. Este estudo analisou a influência que a saída lateral do forame apical e o calibre do instrumento podem exercer na instrumentação do canal cementário. Trinta e quatro incisivos centrais superiores foram divididos em dois grupos: Grupo 1 (n=17), sem preparo cervical, e Grupo 2 (n=17), com preparo cervical com brocas LA Axxess. Limas K com aumentos de diâmetro foram progressivamente inseridas no canal até ajustar no forame apical e as pontas ficarem visíveis e foram fixadas com adesivo de etil cianoacrilato. Os conjuntos raízes/limas foram seccionados transversalmente a 5 mm aquém do ápice. Os ápices foram examinados por microscopia eletrônica de varredura com aumento de 140x e imagens digitais foram capturadas. Os dados foram examinados estatisticamente pelo teste t de Student e teste exato de Fischer com nível de significância de 5%. A microscopia eletrônica de varredura mostrou que 19 (56%) dos forames apicais saíram lateralmente em relação ao ápice radicular, enquanto que 15 (44%) coincidiram com ele. Dificuldade significantemente maior para chegar ao forame apical foi observada no Grupo 2. Os resultados sugerem que quanto mais calibroso for o instrumento foraminal, mais difícil poderá ser a instrumentação do forame apical em canais cementários que apresentam saída lateral.

Apical stress distribution on maxillary central incisor during various orthodontic tooth movements by varying cemental and two different periodontal ligament thicknesses: A FEM study.

Context: During fixed orthodontic therapy, when the stress levels in the periodontal ligament (PDL) exceedsan optimum level, it could lead to root resorption. Aims: To determine an apical stress incident on the maxillary central incisor during tooth movement with varying cemental and periodontal ligament thickness by Finite Element Method (FEM) modeling. Settings and Design: A three dimensional finite element model of a maxillary central incisor along with enamel, dentin, cementum, PDL and alveolar bone was recreated using EZIDCOM and AUTOCAD software. ALTAIR Hyper mesh 7.0 version was used to create the Finite Element meshwork of the tooth. This virtual model was transferred to Finite Element Analysis software, ANSYS where different tooth movements were performed. Materials and Methods: Cemental thickness at the root apex was varied from 200 μm to 1000 μm in increments of 200 μm. PDL thickness was varied as 0.24 mm and 0.15 mm. Intrusive, Extrusive, Rotation and Tipping forces were delivered to determine an apical stress for each set of parameters. Results: Results indicated that an apical stress induced in the cementum and PDL, increased with an increase in cementum and PDL thickness respectively. Apical stress induced in the cementum remained the same or decreased with an increase in the PDL thickness. Apical stress induced in the PDL decreased with an increase in the cementum thickness. Conclusion: The study concluded that the clinical delivery of an orthodontic forces will cause stress in the cementum and PDL. Hence, it is necessary to limit the orthodontic force to prevent root resorption.

Incremental lines in root cementum of human teeth: an approach to their role in age estimation using polarizing microscopy.

Age estimation is an important factor in the identification of an individual in forensic science. The hard tissues of the human dentition are able to resist decay and degradation long after other tissues are lost. This resistance has made teeth useful indicators for age calculation. Recent research indicates that tooth cementum annulations (TCA) may be used more reliably than any other morphological or histological traits of the adult skeleton for age estimation. The purpose of this study was to examine the correlation between age and the number of incremental lines in human dental cementum and to ascertain the best method of studying cementum with respect to different forms of microscopy. Thirty nonrestorable teeth were extracted from 20 people, and longitudinal ground section of each tooth was prepared. Photomicrographs of the area at the junction of apical and middle third of the root under light and polarized microscope were taken. The cementum was composed of multiple light and dark bands that were counted on the photomicrograph with the help of image analysis software and added to the average eruption time of individual tooth. The predicted age of the individual was thus obtained. Results showed a significant correlation between the predicted age and actual chronological age of the individual. These data indicate that quantitation of cementum annuli is a moderately reliable means for age estimation in humans and polarizing microscopy is a better means of visualizing incremental lines of cementum compared to light microscopy.

Evaluation of the risk of a stripping perforation with gates-glidden drills: serial versus crown-down sequences

The aim of this study was to evaluate the remaining dentine/cementum thickness using Gates-Glidden burs in serial and crown-down sequences and to observe which of the two sequences is the safest for preparing mesial roots of molars. Thirty-six left and right human mandibular first molars were selected. Standard access cavities were made and initially explored with Flexofiles sizes 10 and 15 until the tip was visible at the apex. The teeth were embedded in a muffle specially developed for this study using a PVC tube with two parallel metal rods in its lid. Each tooth-block was sectioned 3 mm apically to the furcation using a low-speed saw with a diamond disc. The tooth-block was examined under a microscope and an initial image was captured by a digital video system with 8 X and 12 X magnifications. Finally, the tooth-blocks were reassembled in the muffle so that the canals could be instrumented. After instrumentation the area of each mesial canal as well as the smallest distance to the root furcation were measured again. The mesio-buccal canals (crown-down order) and the mesio-lingual canals (serial sequence) presented an average area of 0.46 ± 0.16 mm² and 0.88 ± 0.27 mm² (P < 0.01), respectively. The mean values of the smallest distance to the furcation for the mesio-buccal and mesio-lingual canals were 0.66 ± 0.19 mm and 0.39 ± 0.13 mm (P < 0.01), respectively. The remaining dentine/cementum thickness using Gates-Glidden burs was greater in the crown-down sequence than in the serial sequence.

Análise estrutural da junção amelocementária dos dentes decíduos em microscopia eletrônica de varredura / Structural analysis of the cemento-enamel junction in deciduous teeth under scanning electron microscopy

A região da junção amelocementária de 263 espécimes obtidos de 167 dentes decpiduos humanos, divididos de acordo com os grupos dentários e faces foi avaliado em microscopia eletrônica de varredura. Os resultados revelaram uma distribuição bastante variável do tipo de relação apresentado pelos tecidos mineralizados na junção amelocementária. A preseça do tipo de relação cemento cobrindo esmalte esteve presente em 47% dos casos, sendo estatisticamente significante (p<0,0001) quando compararda com o tipo de relação onde há dentina esposta, presente em 12% do total dos espécimes. Otipo topo-a-topo, presente em 41% dos casos também mostrou ser estatisticamente significante (p<0,0001) quando comparado com o tipo de dentina esposta. Os resultados encontrados quanto à irregularidade da apresentação da junção amelocementária, assim como algumas possíveis características anatômicas encontradas, levam-nos a caracterizar a região da junção amelocementária dos dentes decíduos como vulnerável à agressões mecânicas, químicas e bacteriológicas

Estudos macro e microscópico da morfologia do terço dentário apical na hipercementose: implicaçöes clínicas e etiopatogênicas / Macro and microscopical studies of apical dental portion morphology in the hypercementosis: clinical and etiopathogenic implications

Cento e sessenta dentes com e sem hipercementose foram analisados macroscopicamente, ao estereomicroscópio sem e com diafanizaçäo e na microscopia óptica de luz, com a finalidade de estudar a anatomia externa e interna do terço apical. Verificou-se que: 1) A hipercementose aumenta consideravelmente o número de canais secundários, canais acessórios e deltas apicais. 2) As modificaçöes na morfologia interna do terço apical dos dentes comprometidos näo säo passíveis de visualizaçäo e identificaçäo radiográfica. 3) O canal principal na grande maioria dos dentes com hipercementose apresenta-se constricto no terço apical associado à mudança da trajetória original ou a canais secundários, acessórios e deltas apicais. 4) O tipo morfológico mais comum de hipercementose dá à raiz a forma de clava. A forma localizada de hipercementose apresenta-se com considerável menor frequência. A forma de boca de manga de camisa encontra-se apenas eventualmente. 5) O padräo morfológico e aposicional do cemento constituinte da hipercementose assemelha-se ao cemento em dentes normais quando observado na microscopia óptica de luz, assim como sua superfície externa. Após estas verificaçöes, concluiu-se que na hipercementose o clínico de várias especialidades, como o cirurgiäo, o ortodontista e especialmente o endodontista, deve considerar a modificaçäo anatômica externa e interna a que foi submetido o dente portador, pois sua forma radicular tende a ser retentiva, o corpo radicular mais espesso e o terço apical mais rico em canalículos e deltas apicais associado à constricçäo e mudança direcional do canal principal

CCTV study of cemental annulations in determining the age from single tooth.

Cementum in human tooth is a hard tissue in its root deposited around dentin in layers throughout the life. Microscopically each layer is seen as a set of alternating dark and light bands and called as Cemental Annulations. Intact teeth obtained from subjects of either sex and of known ages processed by ground sectioning manually and mounted on a glass slide. The cemental annulations were then counted by light microscope using CCTV Screen, at the junction of cervical with middle third of root. Age was then determined by adding the eruption age in years of tooth in study to the annulations counted. This was found to be matching with actual age almost to an accuracy of +/- 1-2 years.

Es el cemento dentario un tejido de escasa vitalidad? / Is the dental cementum a poor-vitality tissue?

Estudios actuales y de investigaciones previas, ponen de manifiesto en la estructura cementaria, su vascularización e inervación. Estos hechos, sumados a los conceptos expuestos por otros investigadores, revelan que el cemento dentario, posee más vitalidad de la que habitualmente se le atribuye

Cambios histológicos en el ligamento periodontal y zonas de mineralización del cemento en áreas de presión producidas por fuerzas ortodónticas en humanos / Histological changes in the periodontal ligament and cementum mineralization zones in areas of pressure produced by orthodontic forces in human beings

El movimiento ortodóncico a nivel dental, causa zonas de presión y zonas de tensión a ambos lados del diente. Se ha descrito cómo en las zonas de presión se observa una región mineralizada relacionada con el cemento radicular y el ligamento periodontal, pero no se sabe con certeza su origen ni sus posibles efectos secundarios. El propósito de este estudio es confirmar la presencia de este tejido mineralizado, determinar si es constante y analizar los eventos celulares para determinar su relación con la anquilosis por trauma y posible subsecuente reabsorción radicular. El experimento se diseñó de tal forma que se obtuvieron treinta y dos especímenes de primeros premolares superiores humanos. Las muestras fueron procesadas para realizar cortes histológicos (microscopía de luz); y para microscopía electrónica de Scanner (SEM y X-ray microanalysis). Los hallazgos indican que a nivel de las zonas de presión producidas por fuerzas ortodónticas, en humanos, se presenta un tejido mineralizado, de tipo cementoide, que produce una unión íntima y focal con el hueso alveolar, dando como resultado una anquilosis también de tipo focal

Relación esmalte-cemento y presencia de caries / Relationship between enamel-cementum and caries presence

Choquet describió 4 casos de relaciones entre esmalte y cemento. En este trabajo se estudia en qué porcentaje se encuentran estas relaciones y las probables variaciones individuales y por caras en una misma pieza dentaria. La posibilidad de que la caries guarde alguna vinculación con un determinado caso. Se estudiaron 140 piezas dentarias las que fueron cortadas axialmente buscando que el corte, adecuadamente refrigerado, se oriente por sectores indemnes o sanos. Lectura con lupa de gran aumento en ambos límites cemento-adamantinos, completando las lecturas con otro corte perpendicular sobre los ya realizados. Los cortes, pulimentados, se observaron con lupa y aquellos de importancia diagnóstica fueron desgastados para observar por transparencia. Aquellos fijados en formol al 10 por ciento fueron sometidos a la reacción de PAS para interpretar el cemento PAS positivo y el proceso de descalcificación cariogénica. Se encontró al cemento cubriendo al esmalte en un 23,57 por ciento, al esmalte contactando con cemento en un 35 por ciento, al esmalte y cemento sin contactar en un 39,29 por ciento y al esmalte sobre cemento en un 2,14 por ciento. La caries en estadíos iniciales estuvo presente en un 37 por ciento del total de casos estudiados, iniciándose en cemento (15,20 por ciento), en dentina (9,60 por ciento), en la unión de esmalte y cemento (9,20 por ciento) o en esmalte (2 por ciento). Existieron variaciones individuales y topográficas por pieza dentaria