Comparison of acquisition and reconstruction parameters and protocols of microtomography images for the diagnosis of incipient caries lesions

Orientador: Francisco Haiter NetoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Os objetivos no presente estudo foram: avaliar a acurácia da Microtomografia Computadorizada (Micro-CT) na identificação de lesões de cárie incipientes em dentes posteriores; e avaliar a influência de parâmetros e protocolos de aquisição e reconstrução no diagnóstico das lesões. Seis dentes posteriores resultando em 12 faces proximais, 6 hígidas e 6 com lesões incipientes de cárie, foram utilizados. Os escaneamentos foram feitos em dois microtomógrafos, SkyScan 1172 e 1174 (Bruker, Kontich, Belgium), que diferem em potência, tendo 100kVp e 100µA e 50kVp e 800µA, respectivamente. Parâmetros de aquisição como: rotation step, frame, filtros, rotação parcial e total foram variados resultando em 16 escaneamentos por dente e cada escaneamento foi reconstruído com 0,15 e 30% de Beam Hardening Correction (BHC). Ao final, 576 grupos de imagens foram avaliados por três examinadores utilizando uma escala de 5 pontos quanto a presença/ausência de lesão de cárie nas faces proximais. O preparo histológico das amostras foi realizado e a análise dos cortes sob luz polarizada foi o padrão-ouro deste trabalho. Não foi observada diferença estatística significativa entre os aparelhos e ambos obtiveram resultados excelentes quanto à acurácia. O equipamento 1174 atingiu 70% e o 1172 atingiu 60% de protocolos com acurácia perfeita. Os parâmetros de rotation step, frame, filtros, rotação parcial e total de forma isolada não influenciaram significativamente os resultados. Quando diferenças significativas, porém pontuais, nos resultados do 1174, foram identificadas, o parâmetro de melhor qualidade resultou em maior acurácia. Quanto aos protocolos do 1174, apenas os protocolos que agruparam os piores parâmetros de aquisição e sem aplicação de BHC diferiram dos demais, apresentando resultados de acurácia satisfatórios/regulares, 0,881 e 0,653. Os protocolos do aparelho 1172 não diferiram entre si. Quando a ferramenta de BHC foi testada, a mesma se mostrou eficaz em aumentar a acurácia dos protocolos para 81,25% de protocolos com acurácia perfeita e corrigir os dois piores protocolos citados anteriormente, ambos chegando à acurácia perfeita. Não foi observada diferença estatística quanto à aplicação ou níveis de BHC para os demais protocolos. Como conclusão, a Micro-CT se mostrou ser um método acurado para a identificação das lesões de cárie incipientes. Os parâmetros de aquisição isolados não tiveram influência determinante sobre o diagnóstico, porém, quando os piores parâmetros foram agrupados, observou-se uma queda significativa na acurácia do método. Apesar de não ter mostrado diferença estatística na maior parte das comparações (0,15,30%), a ferramenta BHC aumentou a acurácia geral dos protocolos e corrigiu protocolos de acurácia insatisfatóriaAbstract: The objectives in the present study were: to evaluate the accuracy of Micro Computed Tomography (Micro-CT) in the identification of incipient caries lesions in posterior teeth; and to evaluate the influence of acquisition and reconstruction parameters and protocols in the diagnosis of the lesions. Six posterior teeth resulting in 12 proximal, 6 sound and 6 incipient caries lesions were used. The scans were done in two equipments, SkyScan 1172 and 1174 (Bruker, Kontich, Belgium), which differ in power, having 100kVp and 100?A and 50kVp and 800?A, respectively. Acquisition parameters such as: rotation step, frame, filters, partial and total rotation were varied resulting in 16 scans per tooth and each scan was reconstructed using 0,15 and 30% of Beam Hardening Correction (BHC). At the end, 576 groups of images were evaluated by three examiners using a 5-point scale for the presence/absence of caries lesion on the proximal faces. The histological preparation of the samples was performed and the analysis of the sections under polarized light was the gold standard of this study. No statistically significant difference was observed between the devices, although both had excellent results in terms of accuracy. Equipment 1174 reached 70% and 1172 reached 60% of protocols with perfect accuracy. The parameters of rotation step, frame, filters, partial and total rotation isolated did not significantly influence the results. When significant differences, however punctual in the results of 1174, were identified, the parameter of better quality resulted in greater accuracy. For the 1174 protocols, only the protocols that grouped the worst acquisition parameters and without BHC application differed from the others, presenting satisfactory/regular accuracy results, 0.881 and 0.653. The protocols of 1172 device did not differ from each other. When the BHC tool was tested, it proved to be effective in increasing the accuracy to 81.25% of perfect accuracy protocols and correcting the two worst protocols cited, both of which reached perfect accuracy. No statistical difference was observed regarding the application or correction levels for the other protocols. In conclusion, Micro-CT presented an excellent performance in the identification of incipient caries lesions. The isolated acquisition parameters had no decisive influence on the diagnosis, but when the worst parameters were grouped, a significant decrease in the accuracy of the method was observed. Although it did not show statistical difference in most comparisons (0,15,30%), the BHC tool increased the overall accuracy of the protocols and corrected protocols of unsatisfactory accuracyDoutoradoRadiologia OdontologicaDoutora em Radiologia Odontológic

Comparison of automatic and visual methods used for image segmentation in Endodontics: a microCT study

To calculate root canal volume and surface area in microCT images, an image segmentation by selecting threshold values is required, which can be determined by visual or automatic methods. Visual determination is influenced by the operator's visual acuity, while the automatic method is done entirely by computer algorithms. Objective: To compare between visual and automatic segmentation, and to determine the influence of the operator's visual acuity on the reproducibility of root canal volume and area measurements. Material and methods: Images from 31 extracted human anterior teeth were scanned with a μCT scanner. Three experienced examiners performed visual image segmentation, and threshold values were recorded. Automatic segmentation was done using the “Automatic Threshold Tool” available in the dedicated software provided by the scanner's manufacturer. Volume and area measurements were performed using the threshold values determined both visually and automatically. Results: The paired Student's t-test showed no significant difference between visual and automatic segmentation methods regarding root canal volume measurements (p=0.93) and root canal surface (p=0.79). Conclusion: Although visual and automatic segmentation methods can be used to determine the threshold and calculate root canal volume and surface, the automatic method may be the most suitable for ensuring the reproducibility of threshold determination

Impact of micronutrients supplementation on bone repair around implants: microCT and counter-torque analysis in rats

ABSTRACT The use of natural substances and micronutritional approaches has been suggested as a therapeutic alternative to benefit the bone healing associated with no side effects. Nevertheless, the influence of micronutritional interventions with therapeutic proprieties on the bone repair has yet to be intensely evaluated, and no evidence is available exploring the impact of micronutrient supplementation on the peri-implant bone healing. Objective This study investigated the effect of micronutrients supplementation on the bone repair around implants. Material and Methods One screw-shaped titanium implant was inserted in each tibia of each rat, which were assigned to: daily administration, for 30 d, of the placebo solution (Placebo group-n:18) or micronutrients supplementation (Micronutrients group-n:18), based on calcium, magnesium, zinc, and vitamin D3 intake. After, the animals were sacrificed. One of the implants was removed by applying a counter-torque force to evaluate the force to rupture the bone-implant interface. The other implant was evaluated by microcomputed tomography (CT) examination to determine the bone-to-implant contact (BIC) and the bone volume (BV/TV). Results No statistically significant differences were observed between the groups for both counter-torque values and microCT parameters (p>;0.05). Conclusion Within the limits of this study, micronutrients supplementation did not provide additional benefits to the bone healing around dental implants

Mucinose oral focal: descrição de um caso clínico

The aim of this article is to report the case of a 23-year-old female patient that sought dental service for examination of an asymptomatic slow-growing large lump in the mandibular gingiva causing displacement of the right first molar. Excisional biopsy, histopathological analysis, Alcian blue/periodic acid-Schiff (PAS) staining and immunohistochemistry analysis for S-100 were performed. The diagnosis established was oral focal mucinosis. After three years, the patient is still under follow-up, without any recurrences. Although cases of oral focal mucinosis of this particular size are rare, this entity should be considered in the differential diagnosis of oral lesions located in the gingiva5015456O objetivo deste artigo é relatar o caso de uma paciente de 23 anos de idade que procurou o serviço odontológico para exame de um grande nódulo de crescimento lento, assintomático, na gengiva mandibular, o que causou deslocamento do primeiro molar direito. Foram realizadas biópsia excisional, análise histopatológica, coloração Alcian blue/periodic acid-Schiff (PAS) e análise imuno-histoquímica para S-100. O diagnóstico de mucinose oral focal foi estabelecido. A paciente ainda está sob acompanhamento, sem recorrência, após três anos. Embora os casos de mucinose oral focal com esse tamanho sejam raros, esta entidade deve ser considerada no diagnóstico diferencial das lesões orais localizadas em gengivasem informaçã

Effect of low shrinkage monomers on physicochemical properties of dental resin composites

The aim of this study was to evaluate the effect of low shrinkage monomers on physicochemical properties of dental resin composites. Two low shrinkage resin composites: one with a crosslink branching monomer (Kalore, GC Corp) and a novel monomer (Venus Diamond, Heraeus Kulzer) were compared to a conventional resin composite formulation (Filtek Z250, 3M/ESPE). The volumetric shrinkage was evaluated by µCT analysis (n=5) and the physicochemical properties by degree of C=C conversion (DC), flexural strength (FS) and Young's modulus (YM) (n=10). All samples were light cured by a LED device (Radii, SDI) with 16 J/cm2. The results were analysed by one-way ANOVA and Tukey test for multiple comparisons (α=0.05). No statistical difference was found between µCT shrinkage values to Kalore (1.8%) and Venus Diamond (1.7%) (p≥0.05); Z250 presented statistical highest shrinkage value (2.0%). Kalore presented higher statistical DC (60.8%) than Venus Diamond (49.5%) and Z250 (49.6%). No statistical difference was found between FS or YM properties to Venus Diamond and Z250; Kalore presented statistical lowest FS and YM properties (p≥0.05). Using novel monomers seem to reduce polymerization shrinkage without affecting the physicochemical properties evaluated of resin composites rather than using crosslink branching monomers.The aim of this study was to evaluate the effect of low shrinkage monomers on physicochemical properties of dental resin composites. Two low shrinkage resin composites: one with a crosslink branching monomer (Kalore, GC Corp) and a novel monomer (Venus Di263272276sem informaçãosem informaçãoO objetivo deste trabalho foi avaliar o efeito de monômeros de baixa contração de polimerização nas propriedades físico-químicas de resinas compostas. Duas resinas de baixa contração de polimerização com monômeros do tipo crosslink (Kalore GC Corp) ou d

Effect of cerium-containing hydroxyapatite in bone repair in female rats with osteoporosis induced by ovariectomy

Osteoporosis is a public health problem, with bone loss being the main consequence. Hydroxyapatite (HA) has been largely used as a bioceramic to stimulate bone growth. In our work, a cerium-containing HA (Ce-HA) has been proposed and its effects on the antimicrobial and bone-inducing properties were investigated. The synthesis of the materials occurred by the suspension–precipitation method (SPM). The XRD (X-ray Diffraction) confirmed the crystalline phase, and the Rietveld refinement confirmed the crystallization of HA and Ce-HA in a hexagonal crystal structure in agreement with ICSD n◦ 26205. Characterizations by FT-IR (Fourier Transform Infrared Spectroscopy), XPS (X-ray Photoemission Spectroscopy), and FESEM-EDS (Field Emission Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) confirmed the presence of cerium (Ce3+ and Ce4+ ). The antibacterial activity of Has was evaluated against Staphylococcus aureus 25,923 and Escherichia coli 25,922 strains, which revealed that the material has antimicrobial properties and the cytotoxicity assay indicated that Ce-containing HA was classified as non-toxic. The effects of Ce-HA on bone repair, after application in bone defects in the tibia of female rats with osteoporosis induced by ovariectomy (OVX), were evaluated. After 15 and 30 days of implantation, the samples were analyzed by Raman, histology and X-ray microtomography. The results showed that the animals that had the induced bone defects filled with the Ce-HA materials had more expressive bone neoformation than the control group.info:eu-repo/semantics/publishedVersio

Study of collagen organization and strength of the periodontal ligament in rat incisors irradiated

Orientador: Pedro Duarte NovaesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Os efeitos adversos da radioterapia sobre os tecidos orais vêm sendo estudados com intuito de, cada vez mais, entender como esta age sobre o organismo, bem como para o desenvolvimento de métodos ou substâncias que visem à minimização dessas sequelas. Dentre os tecidos que estão na área de exposição, está o ligamento periodontal, que se afetado, pode ocasionar a perna dentária que impreterivelmente interfere na qualidade de vida do indivíduo. Este trabalho teve como objetivo avaliar o efeito da radiação ionizante sobre o ligamento periodontal do dente incisivo de rato albinus wistar, por meio da microscopia de polarização e do teste de força. A amostra constituiu-se de 30 ratos albinus wistar machos divididos em dois grupos, o grupo controle (15) e o grupo irradiado (15). O grupo irradiado foi submetido à sessão única de radioterapia com dose de 15Gy e após 14 dias todos os animais foram sacrificados. Um animal de cada grupo foi perdido durante a execução do trabalho. Desta forma, sete animais de cada grupo foram submetidos ao teste de resistência do ligamento periodontal e os sete restantes tiveram a organização do colágeno avaliada através da microscopia de polarização. Os resultados mostraram que ambos os testes apresentaram diferença estatisticamente significante entre os grupos (p<0,001). Através dos coeficientes de correlação de Pearson encontrou-se também uma forte correlação entre os resultados dos testes (resistência/polarização) de cada grupo (controle/irradiado) (R = 0,683; p < 0,001). Portanto, concluiu-se que a radioterapia pode levar à diminuição da resistência à força de intrusão e provocou a desorganização do colágeno no ligamento periodontalAbstract: The adverse effects of radiotherapy on oral tissues have been studied in order to increasingly understand how it works on the body, as well as for the development of methods and substances aimed at minimizing these sequelae. Among the tissues that are in the exposition area, is the periodontal ligament which, when affected, can lead to tooth loss, that unfailingly interferes with quality of life. This study had as purpose to evaluate the effect of ionizing radiation over the periodontal ligament of the incisive tooth of the albinus wistar rat, trough the polarizing microscope and the strength test. The sample was composed of 30 albinus wistar male rats, separated into two groups, the control group (15) and the irradiated one (15). The irradiated group was subjected to an only session of radiotherapy, with a 15Gy dose, and after 14 days all the animals were sacrificed. One animal in each group was lost during the study's execution. Hence, seven animals of each group were subjected to the periodontal's ligament resistance test, and the seven remaining had their collagen organization evaluated trough the polarizing microscopy. The results showed that both tests exhibited statistically significance difference between the groups (p<0,001). Using the Pearson correlation coefficients a strong correlation was also found between the tests results (resistance/polarizing) of each group (control/irradiated) (R = 0,683; p<0,0001). Thereby, the conclusion was that radiotherapy can lead to a diminished resistance to the intrusion strength and to a disorganization of the periodontal's ligament collagenMestradoRadiologia OdontologicaMestra em Radiologia Odontológic

A Survey On Dental Undergraduates’ Knowledge Of Oral Radiology

Dentists’ incorrect behavior with regards to Oral Radiology, as reported in the literature, has been related to inadequate training of undergraduates. Aim: This study assessed dental undergraduates’ knowledge of Oral Radiology. Methods: A questionnaire containing 30 questions pertaining to three domains - General Principles, Radiobiology/Radioprotection and Technique/Interpretation - was used as data collection instrument. A total of 195 students answered the questionnaires. Results: No statistically significant differences were found between second-, third- and fourthyear students (p&gt;0.05) when the whole questionnaire and the General Principles domain (p&gt;0.05) were considered. The Technique/Interpretation domain presented a borderline statistical significance level (p=0.051), with more correct answers attributed to second-year students. A statistically significant difference (p&lt;0.05) was seen for the Radiobiology/Radioprotection domain, in which the fourth-year students performed better. Conclusions: Dental undergraduates’ knowledge of Oral Radiology did not increase or decrease significantly comparing the undergraduate years. However, with the exception of the Technique/Interpretation domain, students of more advanced undergraduate years answered more correctly the questions. Nevertheless, the Technique/ Interpretation domain should be reinforced throughout the undergraduate course.122109-11

A survey on dental undergraduates’ knowledge of oral radiology

Dentists’ incorrect behavior with regards to Oral Radiology, as reported in the literature, has been related to inadequate training of undergraduates. Aim: This study assessed dental undergraduates’ knowledge of Oral Radiology. Methods: A questionnaire containing 30 questions pertaining to three domains - General Principles, Radiobiology/Radioprotection and Technique/Interpretation - was used as data collection instrument. A total of 195 students answered the questionnaires. Results: No statistically significant differences were found between second-, third- and fourth-year students (p>0.05) when the whole questionnaire and the General Principles domain (p>0.05) were considered. The Technique/Interpretation domain presented a borderline statistical significance level (p=0.051), with more correct answers attributed to second-year students. A statistically significant difference (p<0.05) was seen for the Radiobiology/Radioprotection domain, in which the fourth-year students performed better. Conclusions: Dental undergraduates’ knowledge of Oral Radiology did not increase or decrease significantly comparing the undergraduate years. However, with the exception of the Technique/Interpretation domain, students of more advanced undergraduate years answered more correctly the questions. Nevertheless, the Technique/ Interpretation domain should be reinforced throughout the undergraduate course