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.

Parturitions, menopause and other physiological stressors are recorded in dental cementum microstructure.

The life history pattern of recent humans is uniquely derived in many of its aspects including an extended post-reproductive lifespan combined with short interbirth intervals. A number of theories have been proposed to explain the evolution of this unusual pattern. However most have been difficult to test due to the fragmentary nature of the hominin fossil record and the lack of methods capable of inferring such later life history events. In search of a method we tested the hypothesis that the physiologically impactful events of parturition and menopause are recorded in dental cementum microstructure. We performed histomorphological analyses of 47 teeth from 15 individuals with known life history events and were able to detect reproductive events and menopause in all females. Furthermore, we found that other stressful events such as systemic illnesses and incarceration are also detectable. Finally, through the development of a novel analytical method we were able to time all such events with high accuracy (R-squared = 0.92).

Human permanent teeth are divided into two parts at the cemento-enamel junction in the divine golden ratio.

AIM: The aim of this study is to find out whether tooth length (crown length + root length) follows the rule of most divine and mysterious phi (ϕ) or the golden ratio. METHODS: A total of 140 teeth were included in the study. The crown-root ratio was manually calculated using vernier caliper and its approximation to golden ratio or the divine number phi (ϕ) was examined. RESULTS: The average root-crown ratio (R/C) for maxillary central incisor was 1.627 ± 0.04, and of its antagonist, mandibular central incisor was 1.628 ± 0.02. The tooth-root ratio (T/R) for the same was 1.609 ± 0.016 and 1.61 ± 0.008, respectively. Similar values were appreciated for lateral incisors where the R/C ratio in the maxillary and mandibular teeth was 1.632 ± 0.015 and 1.641 ± 0.012 and the T/R ratio was 1.606 ± 0.005 and 1.605 ± 0.005, respectively. CONCLUSION: On measuring the tooth length in linear fashion from the cusp tip to the root apex, we found that the tooth was divided into two parts at the cemento-enamel junction in the golden ratio. This information can be exploited in restorative and implant dentistry in future.

Comparison of verdeluz orange G and modified Gallego stains.

Tumors of the oral cavity include combinations of hard and soft tissues that may be difficult to identify using routine hematoxylin and eosin (H & E) staining. Although combination stains can demonstrate hard and soft tissues, trichrome stains, such as VanGieson and Masson, cannot differentiate dental hard tissues, such as dentin, cementum and osteoid. Modified Gallegos (MGS) and verdeluz orange G-acid fuchsin (VOF) stains can differentiate components of teeth. We used 10 tissue sections of decalcified bone and 10 pathologic tissue sections that contained different calcified tissues including peripheral ossifying fibroma, odontoma, central ossifying fibroma and cemento-ossifying fibroma. Sections were stained with H & E, VOF or MGS. H and E stained both hard tissues pink. VOF stained bone purple-red, cementum red and collagen blue. MGS stained bone green-blue, cementum red and collagen blue. VOF staining intensity and differentiation was better than MGS staining. VOF staining demonstrated hard tissue components distinctly and exhibited good contrast with the surrounding connective tissue. VOF also is a simple, single step, rapid staining procedure.

Intravenous bisphosphonate therapy does not thicken cementum or change periodontal ligaments of cancer patients.

OBJECTIVE: To test the hypothesis that intravenous (IV) bisphosphonate (BP) therapy thickens or alters the micromorphology of cementum and periodontal ligament (PDL) in cancer patients. STUDY DESIGN: Thirty-two teeth extracted from 24 cancer patients and separated into test (patients who have undergone IV BP therapy, n = 16) and control (patients naive to BP therapy, n = 16) groups were studied. Cementum thickness was measured in 3 different areas of the dental root with polarized light microscopy. PDL was assessed by optical light microscopy and the immunohistochemical expression of periostin. RESULTS: No significant difference was detected in cementum thickness (apical, P = .06; medium, P = .16; cervical, P = .18) between groups. The numbers of fibroblasts in PDL (P = .56), incremental lines of cementum (P = .51) and the immunohistochemical patterns of periostin expression in PDL (P = .68) did not differ between groups. CONCLUSION: IV BP therapy does not thicken cementum or change the micromorphology of PDL.

On the discovery of cementum.

Though cementum of the tooth root is critical for periodontal structure and tooth attachment and function, this tissue was not discovered and characterized on human teeth until a full century later than enamel and dentin. Early observations from the seventeenth to the nineteenth centuries by Marcello Malpighi, Antonie van Leeuwenhoek, Robert Blake, Jacques Tenon and Georges Cuvier founded a confusing and conflicting nomenclature that obscured the nature of cementum, often conflating it with bone. Advances in microscopy and histological procedures yielded the first detailed descriptions of human cementum in the 1830s by Jan Purkinje and Anders Retzius, who identified for the first time acellular and cellular types of cementum, and the resident cementocytes embedded in the latter. Comparative anatomy studies by Richard Owen and others over the latter half of the nineteenth century identified coronal and radicular cementum varieties across the Reptilia and Mammalia. The functional importance of cementum was not appreciated until detailed anatomical studies of the periodontium were performed by G.V. Black and others in the late nineteenth and early twentieth centuries. These early studies on cementum laid the foundation for more advanced understanding of cementum ultrastructure, composition, development, physiology, disease, genetics, repair and regeneration throughout the twentieth and into the twenty-first century.

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.

Cementum structure in Beluga whale teeth.

A large fraction of the volume of Beluga whale (Delphinapterus leucas) teeth consists of cementum, a mineralized tissue which grows throughout the life of the animal and to which the periodontal ligaments attach. Annular growth bands or growth layer groups (GLGs) form within Beluga cementum, and this study investigates GLG structure using X-ray fluorescence mapping and X-ray diffraction mapping with microbeams of synchrotron radiation. The Ca and Zn fluorescent intensities and carbonated hydroxyapatite (cAp) diffracted intensities rise and fall together and match the light-dark bands visible in transmitted light micrographs. Within the bands of maximum Ca and Zn intensity, the ratio of Zn to Ca is slightly higher than in the minima bands. Further, the GLG cAp, Ca and Zn modulation is preserved throughout the cementum for durations >25year. STATEMENT OF SIGNIFICANCE: Cementum is an important tooth tissue to which the periodontal ligaments attach and consists primarily of carbonated apatite mineral and collagen. In optical microscopy of cementum thin sections, light/dark bands are formed annually, and age at death is determined by counting these bands. We employ synchrotron X-ray diffraction and X-ray fluorescence mapping to show the bands in Beluga whale cementum result from differences in mineral content and not from differences in collagen orientation as was concluded by others. Variation in Zn fluorescent intensity was found to be very sensitive indicator of changing biomineralization and suggest that Zn plays an important role this process.

Evaluation of the Applicability of Different Age Determination Methods for Estimating Age of the Endangered African Wild Dog (Lycaon Pictus).

African wild dogs (Lycaon pictus) are endangered and their population continues to decline throughout their range. Given their conservation status, more research focused on their population dynamics, population growth and age specific mortality is needed and this requires reliable estimates of age and age of mortality. Various age determination methods from teeth and skull measurements have been applied in numerous studies and it is fundamental to test the validity of these methods and their applicability to different species. In this study we assessed the accuracy of estimating chronological age and age class of African wild dogs, from dental age measured by (i) counting cementum annuli (ii) pulp cavity/tooth width ratio, (iii) tooth wear (measured by tooth crown height) (iv) tooth wear (measured by tooth crown width/crown height ratio) (v) tooth weight and (vi) skull measurements (length, width and height). A sample of 29 African wild dog skulls, from opportunistically located carcasses was analysed. Linear and ordinal regression analysis was done to investigate the performance of each of the six age determination methods in predicting wild dog chronological age and age class. Counting cementum annuli was the most accurate method for estimating chronological age of wild dogs with a 79% predictive capacity, while pulp cavity/tooth width ratio was also a reliable method with a 68% predictive capacity. Counting cementum annuli and pulp cavity/tooth width ratio were again the most accurate methods for separating wild dogs into three age classes (6-24 months; 25-60 months and > 60 months), with a McFadden's Pseudo-R2 of 0.705 and 0.412 respectively. The use of the cementum annuli method is recommended when estimating age of wild dogs since it is the most reliable method. However, its use is limited as it requires tooth extraction and shipping, is time consuming and expensive, and is not applicable to living individuals. Pulp cavity/tooth width ratio is a moderately reliable method for estimating both chronological age and age class. This method gives a balance between accuracy, cost and practicability, therefore it is recommended when precise age estimations are not paramount.

An optical investigation of dentinal discoloration due to commonly endodontic sealers, using the transmitted light polarizing microscopy and spectrophotometry.

The aim of this study was to establish the degree of tooth crown staining by commonly used endodontic sealers. Crown discolorations by tooth canal sealers [AH Plus (Dentsply DeTrey Gmbh, Konstanz, Germany); Endofill (Produits Dentaires SA, Vevey, Switzerland); Apexit (Dentsply DeTrey Gmbh, Konstanz, Germany); and MTA Fillapex (Angelus, Londrina, Brazil)] were tested on extracted human premolars. The samples were divided into five groups of five samples each, after root canal sealing. Five teeth were used as control groups. The spectrophotometric method was performed in order to quantify in terms of color change of the coronal part (it was also recorded a track on how the color changes over time). For the microscopic study of the extracted dental specimens subjected to this study, polarized transmitted light microscopy was used. This method involves the development of special microscopic preparations, called "thin sections". In our case, the thin section was performed on 20 prepared and obturated recently extracted teeth. The degree of discoloration was determined after one week and three months using spectrophotometry and polarized light microscopy. All sealers usually cause some degree of discoloration on the cervical aspect of the crowns that increases in time. AH Plus and Endofill caused the greatest discoloration, followed by Apexit and MTA Fillapex.

Rsk2, the Kinase Mutated in Coffin-Lowry Syndrome, Controls Cementum Formation.

The ribosomal S6 kinase RSK2 is essential for osteoblast function, and inactivating mutations of RSK2 cause osteopenia in humans with Coffin-Lowry syndrome (CLS). Alveolar bone loss and premature tooth exfoliation are also consistently reported symptoms in CLS patients; however, the pathophysiologic mechanisms are unclear. Therefore, aiming to identify the functional relevance of Rsk2 for tooth development, we analyzed Rsk2-deficient mice. Here, we show that Rsk2 is a critical regulator of cementoblast function. Immunohistochemistry, histology, micro-computed tomography imaging, quantitative backscattered electron imaging, and in vitro assays revealed that Rsk2 is activated in cementoblasts and is necessary for proper acellular cementum formation. Cementum hypoplasia that is observed in Rsk2-deficient mice causes detachment and disorganization of the periodontal ligament and was associated with significant alveolar bone loss with age. Moreover, Rsk2-deficient mice display hypomineralization of cellular cementum with accumulation of nonmineralized cementoid. In agreement, treatment of the cementoblast cell line OCCM-30 with a Rsk inhibitor reduces formation of mineralization nodules and decreases the expression of cementum markers. Western blot analyses based on antibodies against Rsk1, Rsk2, and an activated form of the 2 kinases confirmed that Rsk2 is expressed and activated in differentiating OCCM-30 cells. To discriminate between periodontal bone loss and systemic bone loss, we additionally crossed Rsk2-deficient mice with transgenic mice overexpressing the osteoanabolic transcription factor Fra1. Fra1 overexpression clearly increases systemic bone volume in Rsk2-deficient mice but does not protect from alveolar bone loss. Our results indicate that cell autonomous cementum defects are causing early tooth loss in CLS patients. Moreover, we identify Rsk2 as a nonredundant regulator of cementum homeostasis, alveolar bone maintenance, and periodontal health, with all these features being independent of Rsk2 function in systemic bone formation.

Infundibula of equine maxillary cheek teeth: Part 2: Morphological variations and pathological changes.

Incomplete cemental filling of the infundibula of equine maxillary cheek teeth (CT) is a common feature. Depending on the extent of the defect, three stages of infundibular decay have been suggested. However, histomorphological criteria to identify non-pathological abnormalities and destructive changes have not been defined. Six hundred and eighty eight CT with no evidence of dental diseases and 55 diseased permanent, fully erupted maxillary CT were evaluated on a macroscopic level by assessing the occlusal surface and horizontal sections, including porphyrin assays to detect residual blood within the infundibular cementum. Selected specimens were investigated on a microscopic level using routine and immunohistological staining methods to identify possible routes for the spread of infectious agents from the infundibulum into the endodontic system. Infundibular cemental hypoplasia was defined as a non-pathological developmental abnormality and was detected in >50% of CT with no evidence of dental diseases and in >70% of diseased CT. The first molar (Triadan 09) showed the highest prevalence (75%) of infundibular cemental hypoplasia. The mesial infundibulum was more often affected than the distal infundibulum. Infundibular erosion was considered as the most appropriate term to describe destructive infundibular changes. Infundibular erosion was present in <6% of CT with no evidence of dental diseases, but was detected in >27% of diseased teeth, always accompanied by endodontic disease. This suggests that teeth affected by infundibular cemental hypoplasia are prone to destructive erosion, which possibly leads to endodontic disease. Morphological factors that supplement this ethological hypothesis were described. In 74% of infundibula residual blood was identified, although no vital blood vessels were detected. It is assumed that this content of blood remained in the ample infundibular cemental blood system after tooth eruption and creates a favorable environment for microbial growth. The infundibular enamel was characterised by numerous infoldings to variable degrees and depths. In certain areas focal enamel aplasia was observed. These morphological features might contribute to microbiological settlement and spread of infectious agents through the infundibular wall into the endodontic system.

Effect of low-level laser therapy on dental root cementum remodeling in rats.

OBJECTIVE: To investigate the amount of the cementum layer formed over the rat's dental root surfaces by daily application of low-level laser therapy (LLLT) for 2 weeks. METHODS: Twelve female Sprague-Dawley (SD) rats were divided into two groups: six rats received daily LLLT (Ga-Al-As, 830 nm), and six rats received no treatment (control). The treatment lasted 2 weeks. In vivo Micro-CT imaging analyzed the root's hard tissue volumetric changes. The cementum thickness was evaluated histologically. RESULTS: Total cementum thicknesses in the LLLT group increased significantly (p = 0.015) compared to the control group. This significant increase in the cementum thickness, verified histologically, was not detectable during in vivo Micro-CT imaging, which showed no significant difference between the groups regarding the root hard tissues volumetric changes over the 2-week evaluation period. CONCLUSION: Two weeks of daily application of LLLT significantly increased rat's dental root cementum thickness as determined histologically. However, in vivo Micro-CT imaging failed to accurately reveal this cementum growth as it was not possible to differentiate dentinal changes.

Immunohistochemical and histochemical analysis of newly formed tissues in root canal space transplanted with dental pulp stem cells plus platelet-rich plasma.

INTRODUCTION: Tissue regeneration in root canals after pulpectomy can be achieved by transplantation of autologous dental pulp stem cells and/or platelet-rich plasma. However, the identity of the newly formed tissue in the pulp space has been only examined by histologic analysis. This study aimed to apply immunohistochemistry and histochemistry to detect specific markers in the newly generated tissues after root canal regenerative treatment. METHODS: In our previous study, 32 root canals in 4 mature dogs were treated with a pulp regeneration procedure after pulpectomy using either blood clot, transplantation of dental pulp stem cells, platelet-rich plasma, or a combination of cells and plasma. In the present study, the tissues were examined for the expression of periostin to detect periodontal ligament tissue, nestin and dentin sialoprotein for odontoblasts, and bone sialoprotein and osteocalcin for bone tissues. Samples were also stained for tartrate-resistant acid phosphatase (TRAP) as a marker for osteoclastic lineages. RESULTS: Continuous periostin-positive tissue was observed extending from the periodontal ligament into the inner canal surface in which the mineral islands were surrounded by weak periostin staining. There was also positive staining for TRAP, bone sialoprotein, and osteocalcin in the canal space, suggesting the presence of bone tissue. A layer of mineralized tissue along the inner surface of the root canal was negative for TRAP, suggesting the tissue likely to be cementum. In all samples, no nestin-positive reaction was observed, whereas dentin sialoprotein was detected in PDL, dentinal tubules, and intracanal fibrous tissues. There was no difference between any of the 4 groups. CONCLUSIONS: The tissues formed in the dog mature root canals after regenerative endodontic procedures are not pulp tissues but mainly periodontal tissues.

Histologic comparison between platelet-rich plasma and blood clot in regenerative endodontic treatment: an animal study.

INTRODUCTION: In regenerative endodontic treatment (RET) for immature permanent tooth, better treatment results could be obtained by applying platelet-rich plasma (PRP) as the scaffold rather than the blood clot. The goal of this study was to compare the histologic differences between using PRP and blood clot in RET. METHODS: Three 6-month-old beagles each carrying 9 premolars with double root canals were randomly assigned to the PRP group, blood clot group, or negative control group. All experimental teeth suffered apical periodontitis, and RET was performed. In the blood clot group, bleeding was induced from the periapical tissues to fill the canal space. In the PRP group, autologous PRP was injected into each root canal. The animals were sacrificed 3 months later. Histologic sections were stained with hematoxylin-eosin. Statistical analysis was performed by the Fisher exact test, with the significance set at 0.05. RESULTS: With the ingrowth of cellular cementumlike tissues, the canal wall was thickened, and the apical apex was closed in both the PRP and blood clot groups. Cementocytelike cells were present in the newly formed tissues. Meanwhile, no statistical difference was found in both experimental groups for the average percentage of apical closure, new tissue formation, and pulplike tissue formation. Noticeably, a large number of inflammatory cells were present in some root canals in both groups although the postoperative radiograph revealed the disappearance of periapical radiolucency. CONCLUSIONS: PRP application could be an option for clinical cases in which little or no bleeding were found when irritating the apical tissue during RET.

Evaluation of four different optimized magnetic-resonance-imaging sequences for visualization of dental and maxillo-mandibular structures at 3 T.

OBJECTIVES: The purpose of this study was to evaluate four in-house optimized, non-contrast enhanced sequences for MRI-investigation of maxillo-mandibular and dental structures by use of 3 T. METHODS: 12 volunteers with different dental status were examined by using a 3 T MRI with a 20-channel standard head-and-neck coil. All images performed were evaluated by using 3D-techniques, with different slice-thicknesses, in 3D T1- and T2-weighted sequences, as well as by using new techniques of image depictions. In addition phantom measurements were performed to estimate the extent of image artefacts caused by retainers and metal implants. RESULTS: Mean age of the participants was 33 years (range, 25.5-62.75 years), and the sex ratio was 5 females to 7 males. We identified different techniques to improve osseous and dental structures, despite problems caused by dental implants, tooth crowns or braces. CONCLUSION: The sequences evaluated offered excellent visualization in 2D and 3D of osseous and dental structures. Anatomical, osseous and dental structures were described at their ROI, in relation to patients with dental and head and neck pathologies. The ability to detect and distinguish pathological processes as soon as possible in 3D with excellent image quality avoiding ionizing radiation remains a challenging domain.

Three-dimensional defect evaluation of air polishing on extracted human roots.

BACKGROUND: Root surfaces experience continuous abrasive instrumentation during lifelong periodontal maintenance. Periodontists need both effective and minimally abrasive debridement techniques. Air polishing devices might, therefore, constitute a good alternative to mechanical instrumentation. Because little is known of the three-dimensional shape and volume of the abrasion caused by different powders, it is the aim of the study to investigate the three-dimensional extent of these defects. METHODS: Cementum-covered roots of 20 extracted human premolars were coated with resin caps, leaving four areas with identical diameter open for instrumentation using bicarbonate powder and glycine powder. Treatment times were 5 and 10 seconds in a first interval and 10 seconds in a second interval. Maximum settings were chosen for power and lavage. The teeth were scanned using microcomputed tomography initially and after every treatment interval. Differences in volume and defect depths were calculated by superimposition of the scans and tested for significance (Wilcoxon test, P <0.001). RESULTS: Defect volumes (in mm(3)) presented in medians (interquartile ranges) for the bicarbonate powder after 5, 10, 15, and 20 seconds, respectively, were 0.16 (0.11), 0.28 (0.16), 0.32 (0.18), and 0.41 (0.28), and for glycine powder, 0.00 (0.02), 0.01 (0.05), 0.03 (0.11), and 0.06 (0.1). For each time period, abrasion caused by glycine was significantly lower (five- to 20-fold) compared to defects caused by bicarbonate. CONCLUSIONS: In patients with exposed root surfaces, cleaning with bicarbonate powder cannot be recommended. Less abrasive glycine powder, however, demonstrated non-critical substance loss.