O uso do laser de alta e baixa intensidade para o tratamento de hipersensibilidade dentinária: uma revisão integrativa

Objetivo: Determinar as evidências científicas sobre a influência do uso de lasers de baixa e alta intensidade no tratamento da hipersensibilidade da dentina. Revisão de literatura: Foram realizadas buscas na Biblioteca Virtual em Saúde (BVS), incluindo as bases de dados: Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS); Bibliografia Brasileira de Odontologia (BBO); e National Library of Medicine (MEDLINE). A maioria dos estudos destacam a eficácia dos lasers na redução da HD, com o laser Nd:YAG mostrando-se eficaz na obliteração dos túbulos dentinários e proporcionando alívio a longo prazo. Apesar dos benefícios, alguns estudos alertam para possíveis danos à polpa dentária, especialmente com lasers de alta potência. Considerações finais: Embora os lasers tenham se mostrado eficazes na redução da HD, a escolha do laser deve ser personalizada para cada paciente, destacando a necessidade de aprimorar os protocolos clínicos e adquirir experiência relevante por parte dos profissionais especialistas.

Objective: To determine the scientific evidence on the influence of the use of low and high intensity lasers in the treatment of dentin hypersensitivity. Literature review: Searches were carried out in the Virtual Health Library (VHL), including the databases: Latin American and Caribbean Literature in Health Sciences (LILACS); Brazilian Bibliography of Dentistry (BBO); and National Library of Medicine (MEDLINE). Most studies highlight the effectiveness of lasers in reducing HD, with the Nd:YAG laser proving effective in obliterating dentinal tubules and providing long-term relief. Despite the benefits, some studies warn of possible damage to the dental pulp, especially with high-power lasers. Final considerations: Although lasers have been shown to be effective in reducing HD, the choice of laser must be personalized for each patient, highlighting the need to improve clinical protocols and acquire relevant experience on the part of specialist professionals.

Effect of composite radiopacity and margin location of the restoration on the diagnosis of secondary caries

Abstract This research aimed to evaluate the effect of the radiopacity of a Bulk-Fill composite (X-TraFil, VOCO, Germany) and a Conventional composite (P60, 3M ESPE, USA) and assessment of the margin location in the enamel and dentin on the diagnosis of secondary caries. 76 intact premolars with MOD preparation were divided into two equal groups and filled with the conventional and bulk-fill composite. Four regions were considered to simulate carious lesions (two regions in enamel and two regions in dentin). In each group, half of the regions in the dentin and half in the enamel were randomly selected for secondary caries simulation and filled with a wax-plaster combination while the remaining regions stayed intact. Bitewing imaging was done using the PSP digital sensor. Five examiners reviewed the images, and lesions were recorded. Caries diagnosis indicators and paired-sample t-test were used for statistical analysis. The reproducibility and accuracy of the examiners' responses were evaluated using the kappa and agreement coefficient (α=0.05). The sensitivity, specificity, and accuracy of diagnosing secondary carious lesions in enamel were significantly better under conventional than bulk-fill composite. Similarly, the sensitivity and accuracy of diagnosing secondary caries in dentin were significantly higher under conventional composite than bulk-fill composite (p<0.05). No significant differences were found in the agreement and kappa coefficient between conventional and bulk-fill composites in the enamel and dentin (p>0.05). The diagnostic accuracy of carious lesions was higher under conventional composite than bulk-fill composite. However, the location of the secondary was ineffective in caries diagnosis.

Resumo Essa pesquisa teve como objetivo avaliar o efeito da radiopacidade de resina composta Bulk-Fill (X-TraFil, VOCO, Alemanha) e de resina composta convencional (P60, 3M ESPE, EUA) e a avaliação da localização da margem no esmalte e na dentina no diagnóstico de cárie secundária. 76 pré-molares intactos com preparo MOD foram divididos em dois grupos iguais e restaurados de acordo com o grupo experimental. Quatro regiões foram consideradas para simular lesões de cárie (duas regiões no esmalte e duas regiões na dentina). Em cada grupo, metade das regiões na dentina e metade no esmalte foram selecionadas aleatoriamente para a simulação de cárie secundária e preenchidas com uma combinação de cera e gesso, enquanto as regiões restantes permaneceram intactas. As imagens de bitewing foram feitas usando o sensor digital PSP. Cinco examinadores analisaram as imagens, e as lesões foram registradas. Os indicadores de diagnóstico de cárie e o teste t de amostra pareada foram usados para análise estatística. A reprodutibilidade e a precisão das respostas dos examinadores foram avaliadas usando o kappa e o coeficiente de concordância (α=0,05). A sensibilidade, a especificidade e a precisão do diagnóstico de lesões cariosas secundárias no esmalte foram significativamente melhores com a resina composta convencional do que com a resina composta bulk-fill. Da mesma forma, a sensibilidade e a precisão do diagnóstico de cáries secundárias na dentina foram significativamente maiores com a resina convencional do que com a resina bulk-fill (p<0,05). Não foram encontradas diferenças significativas na concordância e no coeficiente kappa entre as resinas convencionais e bulk-fill no esmalte e na dentina (p>0,05). A precisão do diagnóstico de lesões cariosas foi maior com a resina composta convencional do que com a resina composta bulk-fill. Entretanto, a localização do secundário foi ineficaz no diagnóstico de cárie.

Longitudinal bond strength of a universal adhesive and chemical dentin characterization under different acid etching protocols

Abstract Objective This study aimed to analyze the longitudinal bond strength of a universal adhesive and chemically characterize the dentin substrate under different acid etching protocols. Methodology Dentin samples were etched with polyacrylic acid 25% (PAA) for 10 seconds (n=3) and phosphoric acid 32% (PA) for 15 seconds (n=3) and analyzed by Fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR) before and after treatment. For collagen degradation, samples (n=12) were divided into 3 groups: PAA, PA, and Deionized water (control), and analyzed by the quantity of solubilized type I collagen C-terminal cross-linked telopeptides and solubilized C-terminal peptide in relation to total protein concentration (ICTPtp and CTXtp) and by their ultimate tensile strength (UTS). For the adhesive interface analysis, dentin samples (n=72) were divided into 3 groups: PAA, PA, and Self-etch (SE), and subdivided into 2 groups: 24 h (baseline) and 1 year. The following tests were performed: microtensile bond strength (μTBS) (n=48), scanning electron microscopy (SEM) (n=12), and nanoleakage (n=12). Results The FTIR of PAA showed lower reduction of the peaks in the phosphate group when compared to PA. For ICTPtp, PA showed a significantly higher value. For CTXtp, PA and PAA groups failed to statically differ from each other. UTS was significantly lower for PA. For μTBS, storage time significantly affected bond strength. The results were unaffected by the etching protocol. For SEM, after 1 year, PA had little evidence of degradation in the upper third of the adhesive interface in comparison to the other groups. Nanoleakage showed no considerable silver impregnation after 1 year in the SE group. Conclusion The use of PAA prior to a universal adhesive (when compared to PA) represents a less aggressive type of etching to dentin. However, self-etching still seems to be the best option for universal adhesive systems that have functional monomers in their composition.

Efeito protetor de enxaguatórios com diferentes fluoretos utilizados previamente aos desafios erosivos/abrasivos em esmalte e dentina / Protective effect of solutions with different fluorides used previously to erosive/abrasive challenges in enamel and dentin

Aim: To evaluate the protection offered by commercial mouthwashes containing sodium fluoride or stannous chloride associated with sodium fluoride to enamel and dentin, prior to erosive and abrasive cycling. Materials and Methods: Enamel and dentin samples were obtained from bovine incisors and subdivided into 3 groups (n=10), according to the fluoridated ingredient tested: FS (sodium fluoride - NaF (225 ppm)); FE (tin fluoride - NaF + SnCl2 (800 ppm Sn2+)); control (distilled water). The samples were submitted to an erosive/abrasive cycle with immersion in citric acid (lemon soda for 5 min, 4×/day, 5 days, with remineralization intervals in artificial saliva for 60 min). Abrasion was carried out with an electric brush (200 g/force) after the first and last cycles, 2x/day, and immediately afterward immersed in the tested solutions. Structure loss was obtained by optical profilometry. The data were subjected to analysis of variance and multiple comparison for each substrate separately. Results: For enamel there was a difference between the groups (p = 0.027), with the FS showing less loss of structure compared to the control 2.02 (±0.48). The FE group showed similar loss to the control and FS 2.32 (±0.58)ab. For dentin there was a difference between the groups (p = 0.011), with FE showing less loss of structure compared to the other groups, 0.82 (25% - 0.34; 75% - 0.95). Discussion: The protection of fluorides in erosive/abrasive challenges depends on the type and dental substrate. Conclusion: Mouthwash with sodium fluoride prior to erosive/abrasive challenges caused less loss of enamel surface, while for dentin, sodium fluoride associated with stannous chloride caused less loss of structure.

Objetivo: Avaliar a proteção oferecida por soluções para bochecho de fluoreto de sódio ou cloreto de estanho associado ao fluoreto de sódio ao esmalte e à dentina, previamente à ciclagem erosiva e abrasiva. Materiais e Métodos: Amostras de esmalte e dentina foram obtidas a partir de incisivos bovinos e subdivididas em 3 grupos (n=10), de acordo com o princípio ativo fluoretado testado: FS (fluoreto de sódio - NaF (225 ppm)); FE (fluoreto de estanho - NaF + SnCl2 (800 ppm Sn2+)); controle (água destilada). As amostras foram submetidas a um ciclo erosivo/abrasivo com imersão em ácido cítrico (refrigerante de limão por 5 min, 4×/dia, 5 dias, com intervalos de remineralização em saliva artificial por 60 min). A abrasão foi realizada com escova elétrica (200 g/força) após o primeiro e o último ciclos, 2×/dia, e logo em seguida imersos nas soluções testadas. A perda de estrutura foi obtida por perfilometria óptica. Os dados foram submetidos à análise de variância e comparação múltipla para cada substrato separadamente. Resultados: Para esmalte houve diferença entre os grupos (p = 0,027), tendo o FS apresentados menor perda de estrutura comparado ao controle 2,02 (±0,48). O grupo FE apresentou perda similar ao controle e ao FS 2,32 (±0,58)ab. Para dentina houve diferença entre os grupos (p = 0,011), sendo que o FE apresentou menor perda de estrutura comparado aos demais grupos 0,82 (25% - 0,34; 75% - 0,95). Discussão: A proteção dos fluoretos em desafios erosivos/abrasivos depende do tipo e do substrato dental. Conclusão: O bochecho com fluoreto de sódio previamente aos desafios erosivos/abrasivos apresentou menor perda de superfície em esmalte, enquanto para dentina o fluoreto de sódio associado ao cloreto de estanho apresentou menor perda de estrutura.

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

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

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

Continuous Wave of Condensation Improves the Filling of Curved Canals: a Micro-CT Study / La condensación de onda contínua mejora el selle de canales curvos: un estudio de micro-CT

Abstract The aim of this study was to compare the filling capacity in curved root canal using a new continuous wave of condensation technique (Termo Pack II, Easy Dental Equipments, Brazil) or lateral compaction. The percentage of voids in the filling of mesial root canals of mandibular molars was assessed by micro-computed tomography (micro-CT). Mesial root canals (n=24) of mandibular molars with a degree of curvature between 20° and 40° were prepared using rotary system (ProDesign Logic, Easy, Brazil) up to #35, .05 taper. The root canals were filled by using the continuous wave of condensation system or lateral compaction and AH Plus sealer (n=12). Scanning at 9 µm was performed after preparation and after filling by using micro-CT SkyScan 1176. The volumetric percentage of filling material and voids (total length and in each root canal third) were calculated. Data were analyzed using ANOVA/ Tukey and Student's t tests (α=0.05). Before the filling techniques, the root canals volume after preparation was similar (p>0.05). The root canals filled by the continuous wave of condensation technique presented the lowest percentage of voids, and the greatest percentage of filling material in total length and thirds (cervical, middle and apical) (p<0.05). Both techniques were not able of completely filling the root canals. The continuous wave of condensation technique Termo Pack II promoted better root canal filling in curved root canals, when compared with lateral compaction.

Resumen El objetivo de este estudio fue comparar la capacidad de obturación en conductos radiculares curvos utilizando una nueva técnica de condensación de onda continua (Termo Pack II, Easy Dental Equipments, Brasil) vs compactación lateral. El porcentaje de brechas en la obturación de los conductos radiculares mesiales de los molares mandibulares se evaluó mediante microtomografía computarizada (micro-CT). Se prepararon conductos radiculares mesiales (n=24) de molares mandibulares con un grado de curvatura entre 20° y 40° utilizando un sistema rotatorio (ProDesign Logic, Easy, Brasil) al #35, conicidad 0,05. Los conductos radiculares se obturaron utilizando un sistema de condensación de onda contínua o compactación lateral y cemento AH Plus (n=12). Se realizó un escaneo de 9 µm después de la preparación y después de la obturación usando el micro-CT SkyScan 1176. Se calculó el porcentaje volumétrico de material de obturación y vacíos (longitud total y en cada tercio del conducto radicular). Los datos se analizaron utilizando las pruebas ANOVA/Tukey y t de Student (α=0,05). Antes de las técnicas de obturación, el volumen de los conductos radiculares después de la preparación fue similar (p>0,05). Los conductos radiculares obturados con la técnica de condensación por onda contínua presentaron el menor porcentaje de vacíos y el mayor porcentaje de material de obturación en longitud total y en tercios (cervical, medio y apical) (p<0,05). Ambas técnicas no fueron capaces de llenar completamente los conductos radiculares. La técnica de condensación de onda contínua Termo Pack II promovió un mejor relleno del conducto radicular en conductos radiculares curvos en comparación con la compactación lateral.

PREVENTIVE EFFECT OF CRANBERRY GEL ON DENTIN SUBMITTED TO EROSION

Aims: Considering that Cranberry's components might inhibit dentin metalloproteinases exposed to erosive agents, the aim of this study was to evaluate in situeffect of a Cranberry gel application on dentin before an erosive challenge.Materials and methods: This crossover double-blinded study was performed in 2 phases of 5 days each, with 10 healthy volunteers who wore 2 palatal devices (1 for each phase) with 4 dentin specimens (2 specimens for each group). The groups under study were:First Phase: G1 -Erosivechallenge (Coca-cola®) over dentin without any previous treatment (1st negative control group); G2 -Erosive challenge over dentin previously treated with Cranberry gel (test group); and Second Phase: G3 -Erosive challenge over dentin previously treated with a gel without any active principle (2ndnegative control group); G4 -Erosive challenge over dentin previously treated with 0.12% Chlorhexidine gel (positive control group). Each device was immersed into the acid beverage, 3 times daily for 5 minutes during 5 days. Profilometry (µm) was used to quantify the dentin wear. Data were analyzed by Repeated Measures Analysis of Variance followed by Fisher's test (p<0.05).Results: Data (G1: 4.98 ± 1.36a; G2: 3.29 ± 1.16b; G3: 4.38 ± 1.19a; G4: 3.32 ± 1.55b) showed no statistical difference between G1 and G3. There was also no difference between G2 and G4. However, G2 and G4 presented lower wear when compared to G1 and G3, and this difference was statistically significant. Conclusion: The results of this studysuggest a significant efficacy of Cranberry gel in preventing wear of dentin subjected to dental erosion.

The potential of galactomannan from Caesalpinia ferrea on erosive dentin wear reduction in vitro

Abstract Gels containing juca seed galactomannan (JSG) were evaluated for their potential to prevent the progression of dentin erosive wear in an in vitro study with four experimental groups (n = 9). The treatments included distilled water (DW), 0.05% stannous fluoride (121 ppm F), and 0.5% or 1% JSG. The specimens underwent a cycle (3 times/day) consisting of immersion in 1% citric acid (5 minutes), treatment (5 minutes), and artificial saliva exposure (2 hours/overnight) for 5 days. Surface changes were assessed using mechanical profilometry (wear), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The data were analyzed using ANOVA followed by Tukey's post-test (p < 0.05). The negative control group exhibited the highest wear (6.0 µm ± 3.5), significantly differing from the group treated with 0.05% stannous fluoride gel (p = 0.007), which showed less dentin loss. The groups treated with 0.5% and 1% JSG showed results similar to the negative control (p = 0.661; p = 0.212, respectively) and the stannous fluoride group (p = 0.103; p = 0.379, respectively). In the SEM images, the specimen treated with stannous fluoride showed obliterated tubules, while the JSG gels formed crystals on the dentin surface, as confirmed by the presence of oxygen and calcium in the EDS analysis. Although the JSG gels showed similar results to the stannous fluoride, did not exhibit superior efficacy at the tested concentrations.

Resumo Géis contendo galactomanana da semente de jucá (GSJ) foram avaliados quanto ao seu potencial na prevenção da progressão do desgaste erosivo dentinário em um estudo in vitro com quatro grupos experimentais (n = 9). Os tratamentos incluíram água destilada (AD), 0,05% de fluoreto de estanho (121 ppm F) e 0,5% ou 1% de GSJ. Os espécimes passaram por um ciclo (3 vezes ao dia) que consistia em imersão em ácido cítrico 1% (5 minutos), tratamento (5 minutos) e exposição a saliva artificial (2 horas/durante a noite) por 5 dias. As alterações de superfície foram avaliadas utilizando perfilometria mecânica (desgaste), microscopia eletrônica de varredura (MEV) e espectroscopia de raios-X por dispersão de energia (EDS). Os dados foram analisados por ANOVA, seguida do pós-teste de Tukey (p < 0,05). O grupo controle negativo apresentou o maior desgaste (6,0 µm ± 3,5), diferindo significativamente do grupo tratado com gel de fluoreto de estanho a 0,05% (p = 0,007), que apresentou menor perda de dentina. Os grupos tratados com 0,5% e 1% de GSJ apresentaram resultados semelhantes ao grupo controle negativo (p = 0,661; p = 0,212, respectivamente) e ao grupo de fluoreto de estanho (p = 0,103; p = 0,379, respectivamente). Nas imagens de MEV, o espécime tratado com fluoreto de estanho mostrou túbulos obliterados, enquanto os géis GSJ formaram cristais na superfície da dentina, como confirmado pela presença de oxigênio e cálcio na análise de EDS. Embora os géis GSJ tenham apresentado resultados semelhantes ao fluoreto de estanho, eles não demonstraram eficácia superior nas concentrações testadas.

Qualitative Characterization of the Abrasive Component of Charcoal-Containing Toothpastes and the Effect on Dentin Roughness / Caracterización Cualitativa del Componente Abrasivo de las Pastas Dentales que Contienen Carbón Vegetal y la Rugosidad de la Dentina

This study investigated the effect of commercially available whitening toothpastes containing charcoal on dentin. Nine charcoal-containing toothpastes were compared with 3 whitening toothpastes (positive control) and distilled water (negative control). Periodontally hopeless molars were cleaned and washed and the occlusal table removed to expose dentin. The teeth were mounted in auto-polymerizing resin and exposed dentine surfaces polished with water-cooled decreasing grits of silica carbide paper up to 1500 grit. Baseline average roughness (Ra) measurements were taken. Specimens were then mounted in an automatic tooth-brushing machine and brushed for 5000 cycles. Repeat Ra measurements were taken. Specimens were brushed in 5000-cycle increments up to 25,000 cycles with Ra measurements being taken at each time point. Between abrasive challenges specimens were stored in distilled water. All toothpaste samples were sputter coated and examined under a scanning electron microscope to qualify the shape and size of the abrasive components of the formulations. Data were analyzed using a two-way analysis of variance with post hoc Bonferroni. The results demonstrated that the abrasive effect, in terms of increasing Ra, on dentin was noted as early as 5000 cycles for all the tested toothpastes (p<0.05). The effect of continued brushing showed an overall cumulative effect on dentine roughness up to 25000 cycles. When toothpastes were compared between groups at each time-point, dentin specimens brushed with Pursito were statistically similar to the control group. At 25,000 cycles all dentin samples were significantly rougher compared to Pursito and the control groups. It may be concluded that all the tested toothpastes have an abrasive effect on dentin surfaces.

Este estudio investigó el efecto sobre la dentina de las pastas dentales blanqueadoras disponibles en el mercado que contienen carbón vegetal. Se compararon nueve dentífricos que contenían carbón vegetal con 3 dentífricos blanqueadores (control positivo) y agua destilada (control negativo). Los molares sin material periodontal se limpiaron y lavaron y se retiró la tabla oclusal para exponer la dentina. Los dientes se montaron en resina autopolimerizable y las superficies expuestas de la dentina se pulieron con papel de carburo de sílice de grano decreciente enfriado con agua hasta grano 1500. Se tomaron medidas de rugosidad promedio (Ra) de referencia. Luego, las muestras se montaron en una máquina automática de cepillado de dientes y se cepillaron durante 5000 ciclos. Se tomaron medidas repetidas de Ra. Las muestras se cepillaron en incrementos de 5000 ciclos hasta 25 000 ciclos y se tomaron medidas de Ra en cada punto de tiempo. Entre periodos abrasivos, las muestras se almacenaron en agua destilada. Todas las muestras de pasta de dientes se recubrieron por pulverización catódica y se examinaron bajo un microscopio electrónico de barrido para calificar la forma y el tamaño de los componentes abrasivos de las formulaciones. Los datos se analizaron utilizando un análisis de varianza de dos vías de Bonferroni post hoc. Los resultados demostraron que el efecto abrasivo, en términos de aumento de Ra, sobre la dentina se notó ya en 5000 ciclos para todas las pastas dentales probadas (p<0,05). El efecto del cepillado continuo mostró un efecto acumulativo general sobre la rugosidad de la dentina hasta 25.000 ciclos. Cuando se compararon las pastas dentales entre los grupos en cada momento, las muestras de dentina cepilladas con Pursito fueron estadísticamente similares al grupo de control. A los 25.000 ciclos, todas las muestras de dentina eran significativamente más ásperas en comparación con Pursito y los grupos controles. Se puede concluir que todas las pastas dentales probadas tienen un efecto abrasivo sobre las superficies dentinarias.

Demineralized dentin matrix technique - a comparison of different demineralizing solutions

Abstract This study aimed to evaluate the microstructure formed after the chemical treatment of teeth, for the development of autogenous grafts from the demineralized dentin matrix (DDM) technique, in order to identify the most efficient demineralizing solution. The specimens, originating from the root and coronal portion, were submitted to ultrasonic cleaning and drying in an oven for 1h at 100 ºC. Then, the density was determined by Archimedes' principle for each specimen, using distilled water as immersion liquid. The samples were separated into five groups: Control group: negative control, Distilled water;EDTA group: positive control, trisodium EDTA; NaOCl group: 2.5% sodium hypochlorite; HCl-0.6M group: 0.6M hydrochloric acid; and H2O2/H2SO4 group: hydrogen peroxide and sulfuric acid. Each specimen was immersed for 1h in the corresponding group descaling solution at 60 ºC. Subsequently, the mass loss and density of the treated specimens were determined by Archimedes' principle. Ultimately, the specimens of each group were characterized by microtomography, Scanning Electron Microscopy, and Energy Dispersive Spectrometry X-ray (SEM-EDS). The results demonstrated that the H2O2/H2SO4 solution allowed the formation of interconnected micropores, suggesting better pore structures for application in scaffolds, when compared to the other studied solutions.

Resumo Este estudo teve como objetivo avaliar a microestrutura formada após o tratamento químico em dentes, para o desenvolvimento de enxertos autógenos a partir da técnica de matriz de dentina desmineralizada (DDM), a fim de identificar a solução desmineralizante mais eficiente. Os espécimes, provenientes da raiz e porção coronal, foram submetidos à limpeza ultrassônica e secagem em estufa por 1h a 100 ºC. Em seguida, a densidade foi determinada pelo princípio de Arquimedes para cada espécime, utilizando água destilada como líquido de imersão. As amostras foram separadas em cinco grupos: Controle: controle negativo, Água destilada; EDTA: controle positivo, EDTA trissódico; NaOCl: hipoclorito de sódio 2,5%; HCl-0.6M: ácido clorídrico 0,6M; e H2O2/H2SO4: peróxido de hidrogênio e ácido sulfúrico. Cada espécime foi imerso por 1h na solução descalcificante de grupo correspondente a 60 ºC. Posteriormente, a perda de massa e a densidade dos espécimes tratados foram determinadas pelo princípio de Arquimedes. Por fim, os espécimes de cada grupo foram caracterizados por microtomografia, microscopia eletrônica de varredura e espectrometria de energia dispersiva de raios-X (SEM-EDS). Os resultados demonstraram que a solução H2O2/H2SO4 permitiu a formação de microporos interligados, sugerindo melhores estruturas de poros para aplicação em scaffolds, quando comparada às demais soluções estudadas.

Root filling quality and bond strength of endodontic sealers to human and bovine dentin / Qualidade da obturação e resistência de união de cimentos endodônticos à dentina humana e bovina

Objetivo: Este estudo teve como objetivo comparar a qualidade da obturação e a resistência de união de dois cimentos endodônticos, AH Plus e Bio-C Sealer, em dentes humanos e bovinos. Métodos: Os canais radiculares de 60 dentes unirradiculares [30 humanos (H) e 30 bovinos (B)] foram preparados e obturados por condensação lateral da guta-percha e AH Plus (grupos AP-H e AP-B) ou Bio-C Sealer (grupos BC-H e BC-B). Seis fatias de 1,5 mm de espessura foram obtidas de cada raiz. Os espécimes foram observados em estereomicroscópio para avaliar a qualidade da obturação, considerando possíveis espaços vazios no material obturador. Posteriormente, as fatias radiculares foram avaliadas em termos de resistência de união por push-out e modo de falha. Os dados foram analisados pelos testes de Mann-Whitney e coeficientes de correlação de Spearman (α=5%). Resultados: A qualidade de obturação fornecida por AP e BC foi semelhante em ambos os substratos de dentina. No entanto, ao comparar dentes humanos e bovinos, os escores de espaços vazios foram maiores nas amostras bovinas, para ambos os cimentos. AP teve maior resistência de união à dentina humana e bovina do que BC. No entanto, não houve diferença significativa na resistência de união entre os substratos dentinários, para ambos os cimentos testados. Além disso, houve uma correlação positiva e moderada entre os valores de resistência de união de dentes humanos e bovinos. O modo de falha misto foi o mais prevalente. Conclusão: AP e BC fornecem qualidade de obturação semelhante, mas o primeiro apresenta maiores valores de resistência de união à dentina humana e bovina. A utilização de dentes bovinos como substitutos de amostras humanas parece ser adequada em estudos relacionados à resistência de união, mas não naqueles que testam a qualidade da obturação endodôntica.(AU)

Objective: This study aimed to compare the filling quality and bond strength of two endodontic sealers, AH Plus and Bio-C Sealer, in human and bovine teeth. Methods: The root canals of 60 [30 human (H) and 30 bovine (B)] single-rooted teeth were prepared and filled by lateral condensation of gutta-percha and AH Plus (groups AP-H and AP-B) or Bio-C Sealer (groups BC-H and BC-B). Six 1.5-mm-thick slices were obtained from each root. The specimens were observed under a stereomicroscope to assess filling quality, considering possible voids within the filling material. Subsequently, root slices were evaluated in terms of push-out bond strength and failure mode. Data were analyzed by Mann-Whitney tests and Spearman correlation coefficients (α=5%). Results: The filling quality provided by AP and BC was similar in both dentin substrates. However, when comparing human and bovine teeth, void scores were greater in the bovine samples, for both sealers. AP had higher bond strength to human and bovine dentin than BC. However, there was no significant difference in bond strength between dentin substrates, for both sealers tested. Also, there was a positive and moderate correlation between the bond strength values of human and bovine teeth. The mixed failure mode was the most prevalent. Conclusion: AP and BC provide similar filling quality, but the first presents higher bond strength values to human and bovine dentin. The use of bovine teeth as substitutes for human samples seems adequate in studies related to bond strength, but not in those testing root canal filling quality.(AU)

Effect of voxel size of Micro-CT on the assessment of root canal preparation

The aim of this study was to assess the influence of micro-computed tomography (micro-CT) voxel size on evaluation of root canal preparation using rotary heat-treated nickel-titanium files. Curved mesial root canals of mandibular molars were prepared using ProDesign Logic 30/.05 (PDL) or HyFlex EDM 25/.08 (HEDM) (n=12). The specimens were scanned using micro-CT with 5μm of voxel size before and after root canal preparation. Images with sub-resolution of 10 and 20μm voxel sizes were obtained. The percentage of volume increase, debris and uninstrumented root canal surface were analyzed in the different voxel sizes. Data were compared using unpaired Student's t-test and ANOVA statistical tests (α=0.05). No differences were observed for percentage of volume increase, debris and instrumented surface between the root canals prepared by PDL and HEDM (p>0.05). Both systems promoted higher percentage of debris in the apical third compared to the middle third (p0.05). PDL and HEDM had similar root canal preparation capacity. Micro-CT images using different voxel sizes did not influence the results of volume increase and debris evaluation. However, images at 5µm showed greater accuracy to evaluate the percentage of uninstrumented surfaces.

El objetivo de este estudio fue evaluar la influencia del tamaño de vóxel de la microtomografía computarizada (micro-CT) en la evaluación de la preparación del conducto radicular utilizando limas rotatorias de níquel-titanio tratadas térmicamente. Se prepararon conductos radiculares mesiales curvos de molares mandibulares usando ProDesign Logic 30/.05 (PDL) o HyFlex EDM 25/.08 (HEDM) (n=12). Las muestras se escanearon usando micro-CT con un tamaño de vóxel de 5μm antes y después de la preparación del conducto radicular. Se obtuvieron imágenes con subresolución de vóxeles de 10 y 20μm. Se analizó el porcentaje de aumento de volumen, residuos y superficie del conducto radicular no instrumentado en diferentes tamaños de vóxel. Los datos se compararon usando la prueba t de Student no pareada y las pruebas estadísticas ANOVA (α=0,05). No se observaron diferencias en el porcentaje de aumento de volumen, detritus y superficie instrumentada entre los conductos radiculares preparados por PDL y HEDM (p>0,05). Ambos sistemas promovieron un mayor porcentaje de detritos en el tercio apical en comparación con el tercio medio (p0,05). PDL y HEDM tenían una capacidad de preparación del conducto radicular similar. Las imágenes de micro-CT que utilizan diferentes tamaños de vóxel no influyeron en los resultados de la evaluación del volumen y los desechos. Sin embargo, las imágenes de 5µm mostraron una mayor precisión al evaluar el porcentaje de superficies no instrumentadas.

Determination of ABO Blood Grouping from Dentin and Pulp from Freshly Extracted Teeth and Teeth Stored in Sea Water Using Absorption Elution and Absorption Inhibition Method

Introduction: Forensic Odontology plays a role in discerning a deceased individual in any disaster condition. In highly necrotised bodies, ABO blood group antigens can be found from teeth. Aim: We studied ABO blood grouping from dentin and pulp in freshly extracted teeth and also from the teeth stored in sea water. Materials and Methods: A total of 60 samples were selected & divided into 3 groups with 20 samples each. Group I analyzed within period of a week without any storage medium, group II, III were analyzed after 1 and 2 month of storage in sea water. Results: Statistical analysis was done using chi square test. By Absorption –Elution, pulp in group I, II, III, gave 90%,75%,75% of positivity. In dentin, Group I, II, III showed 55%, 45%, 20% of positivity. By Absorption -Inhibition method pulp in group I, II, III showed 45%, 20%, 0% of positivity. In dentin, group I, II, III showed 20%,5%,5% of positivity. Conclusion: This study concluded that pulp is most reliable than dentin even in sea water storage and absorption elution is most effective method in blood group identification in teeth than absorption inhibition method. ==================================== Introduction: Oral cancer (OC) is associated with various risk factors and high mortality rates, and contributes significantly to the worldwide cancer burden. Objectives: To assess and evaluate patients’ current knowledge, awareness, and behavior regarding OC risk in a cancer trust hospital. Materials and Methods: The study involved 600 patients who attended cancer trust hospital, East Godavari district, from September 2021 to October 2021. A self- administered questionnaire of 20-questions was given to each patient that included socio-demographic and disease-specific information and their answers evaluated. Results: The data was examined using descriptive statistics, and the connection between the variables, education, family income, and other factors was assessed using a chi-square test (with a 5% significance threshold). The results were analysed with reference to their implications for interventions aimed at patient’s awareness for oral cancer symptoms. Conclusion: According to the findings of this study, people lacked information and awareness about identified risk factors for oral cancer. Knowledge of maintaining a healthy lifestyle that eliminates the consumption of established oral cancer risk factors was low. At the community and individual levels, health education linked to primary prevention of oral cancer must be improved.

Anti-erosion effect of an experimental varnish on eroded dentin

Abstract This in vitro study evaluated the effect of an experimental varnish containing 20% nano-hydroxyapatite (nHAP) associated with 5% stannous chloride (SnCl2) against erosive-abrasive wear on bovine dentin. Samples of bovine cervical dentin were pre-eroded (0.3% citric acid, pH 2.6 for 10 minutes) and randomized into 4 groups (n=10): Control group - experimental varnish without active ingredient (CG); experimental varnish containing 20% nHAP (nHG); experimental varnish containing 5% SnCl2 (24.800 ppm Sn2+) (SnG); experimental varnish containing 20% nHAP associated with 5% SnCl2 (18.300 ppm Sn2+) (nHSnG). After applying the materials, the erosive-abrasive challenges were performed for five days. Erosive dentin loss and analysis of the pattern of dentinal obliteration were performed by 3D confocal laser microscopy. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The SnG and nHSnG experimental groups presented more effectiveness in preventing erosive wear when compared to the other groups (p<0.05). There was no statistically significant difference between the SnG and nHSnG groups (p = 0.731) in tooth structure dentin loss. Regarding the amount of open dentinal tubules, the highest amount of obstructed dentinal tubules was demonstrated in SnG and nHSnG (p < 0.05) when compared to the others. Between SnG and nHSnG there was no significant difference (p = 0.952) in the amount of closed dentinal tubules in the dentin. Experimental varnishes containing 5% SnCl2 associated or not with 20% nHAP showed to be a promising strategy in preventing erosive-abrasive wear of dentin. In addition, nHSnG was able to obliterate dentinal tubules.

Resumo Este estudo in vitro avaliou o efeito de um verniz experimental contendo 20% de nano-hidroxiapatita (nHAP) associado a 5% de cloreto estanoso (SnCl2) contra o desgaste erosivo-abrasivo da dentina bovina. As amostras de dentina cervical bovina foram pré-erodificadas (0,3% de ácido cítrico, pH 2,6 durante 10 minutos) e aleatorizadas em 4 grupos (n=10): Grupo controle - verniz experimental sem ingrediente ativo (GC); verniz experimental contendo 20% nHAP (GnH); verniz experimental contendo 5% SnCl2 (24.800 ppm Sn2+) (GSn); verniz experimental contendo 20% nHAP associado a 5% SnCl2 (18.300 ppm Sn2+) (GnHSn). Após a aplicação dos materiais, os desafios erosivo-abrasivos foram realizados durante cinco dias. Perda de dentina erosiva e análise do padrão de obliteração dentinária foram realizadas por microscopia laser confocal 3D. Foi realizado o teste ANOVA/Bonferroni unidireccional para analisar os dados (α=0,05). Os grupos experimentais GSn e GnHSn apresentaram maior eficácia na prevenção do desgaste erosivo quando comparados com os outros grupos (p<0,05). Não houve diferença estatisticamente significativa entre os grupos GSn e GnHSn (p = 0,731) na perda de dentina da estrutura dentária. Relativamente à quantidade de túbulos dentinários abertos, a maior quantidade de túbulos dentinários obstruídos foi demonstrada em GSn e GnHSn (p < 0,05) quando comparada com os outros grupos. Entre GSn e GnHSn, não houve diferença significativa (p = 0,952) na quantidade de túbulos dentinários fechados na dentina. Os vernizes experimentais contendo 5% de SnCl2 associados ou não a 20% de nHAP mostraram ser uma estratégia promissora na prevenção do desgaste erosivo-abrasivo da dentina. Além disso, o GnHSn conseguiu obliterar os túbulos dentinários.

Bond strength of composite resin/universal adhesive to dentin submitted to radiotherapy / Fuerza de unión de resina compuesta/adhesivo universal a dentina sometida a radioterapia

Aim: To evaluate the bond strength of a universal adhesive system to dentin submitted to radiotherapy. Materials and Methods: Sixty extracted human teeth were divided into two groups (n = 30): without radiotherapy (control); with radiotherapy, according to the adhesive protocol (n=15): ER-etch-and-rinse (acid + Single Bond Uni-versal); SE-self-etch (Single Bond Universal). The analyzes were shear bond strength (SBS) (n=10), failure pattern (n=10) and scanning electron microscopy (n=5). Data was analyzed by a two-way ANOVA (α =0.05). Results: The radiotherapy decreased SBS of the restorative material to dentin (p<0.0001). The ER protocol provided lower bond strength values (p<0.001). The predominant type of fracture without radiotherapy was mixed (SE), cohesive to the material (ER). Both protocols presented adhesive failures with radiotherapy. Teeth had a hybrid layer and long resin tags (without radiotherapy) and few tags (with radiotherapy). Conclusions: The SE adhesive mode favors the shear bond strength of resin to dentin in teeth submitted to radiotherapy.

Objetivo: Evaluar la fuerza de adhesión de un sistema adhesivo universal a la dentina sometida a radioterapia. Materiales y Métodos: Sesenta dientes humanos extraídos se dividieron en dos grupos (n = 30): sin radioterapia (control); con radioterapia, según protocolo adhesivo (n=15): ER-grabado y enjuague (ácido + Single Bond Universal); autograbado SE (Single Bond Universal). Los análisis ejecutados fueron resistencia al cizallamiento (SBS) (n=10), patrón de falla (n=10) y microscopía electrónica de barrido (n=5). Los datos se sometieron al test de ANOVA de dos vías (α =0,05). Resultados: La radioterapia disminuyó la SBS del material restaurador a la dentina (p<0,0001). El protocolo ER proporcionó valores de fuerza de unión más bajos (p<0,001). El tipo de fractura predominante sin radioterapia fue mixta (SE), cohesiva al material (ER). Ambos protocolos presentaron fallas adhesivas con radioterapia. Los dientes tenían una capa híbrida y colas de resina largas (sin radioterapia) o pocas colas de resina (con radioterapia). Conclusión: El modo adhesivo SE favorece la resistencia al corte de la resina a la dentina en dientes sometidos a radioterapia.

Irrigation protocols effects on radicular dentin: Cleaning, disinfection and remaining ultrastructure / Efecto del protocolo de irrigación en la dentina radicular: limpieza, desinfección y ultraestructura remanente

A successful endodontic treatment requires a combination of satisfactory mechanical instrumentation, adequate irrigation protocols, and three-dimensional obturation of the canal system. Irrigation is considered the most critical procedure to ensure cleaning and disinfection. To date, a large variety of irrigants has been proposed. However, sodium hypochlorite (NaOCl) remains the gold standard. In order to achieve complete cleaning and disinfection, final irrigation with EDTA and ultrasonic devices has been used as an ideal protocol. Most endodontic research focuses on the cleaning and antibacterial properties of the irrigant solutions. Recent evidence demonstrated that the irrigation protocols cause erosion, affecting the radicular dentin ultrastructure. This article aims to describe the clinical features of the present knowledge concerning the effect of irrigation protocols on radicular dentin.

Un tratamiento de endodoncia exitoso requiere de una satisfactoria instrumentación mecánica, protocolos de irrigación adecuados y obturación tridimensional del sistema de conductos radiculares. La irrigación se considera el procedimiento más crítico para garantizar la limpieza y desinfección. Hasta la fecha, se ha propuesto una gran variedad de irrigantes. Sin embargo, el hipoclorito de sodio (NaOCl) sigue siendo el estándar de oro. Para lograr una limpieza y desinfección completa, se ha utilizado como protocolo ideal la irrigación final con EDTA y dispositivos ultrasónicos. La mayor parte de la investigación en endodoncia se enfoca en las propiedades antibacterianas y de limpieza de las soluciones de irrigación. Reciente evidencia demostró que los protocolos de irrigación provocan erosión, afectando la ultraestructura de la dentina radicular. Este artículo tiene como objetivo describir algunas consideraciones clínicas del conocimiento actual sobre el efecto de los protocolos de irrigación en la dentina radicular.

Estimation of dental age using the kvaal method with digital panoramic radiographs in peruvian adults / Estimación de la edad dental según el método de Kvaal con radiografías panorámicas digitales en adultos peruanos

To determine the accuracy of the Kvaal method in the estimation of dental age through the analysis of digital panoramic radiographs of patients between 20 and 47 years of age who attended the stomatological clinic of the Universidad Científica del Sur, (2018 to 2019), Lima-Perú. 289 digital panoramic radiographs belonging to individuals of both sexes, aged 20 to 47 years were analyzed. Length and width measurements were obtained in the dental and pulp chamber in the upper central incisors. These data were subsequently evaluated by calculating the proportions between the pulp and root length of the upper central incisor by applying the formula of the method of Kvaal et al. to obtain the accuracy of the method in estimating dental age. Applying the formula of Kvaal et al. indicates that the relationship between the width of the pulp and the length of the root has a higher level of significance in relation to others proportions: M mean value of all ratios except T (-0.659) and W-L difference between W and L (-0.643). The coefficient of determination (r²) and standard error of estimation (SEE) using the original Kvaal formula is r²: 0.70, SEE: 4.90 years, then a modified Kvaal formula was proposed for the Peruvian population. The Method of Kvaal et al. has an accuracy of 1.24 in estimating the dental age of individuals, using the upper central incisor in digital panoramic radiographs.

Determinar la precisión del método de Kvaal en la estimación de la edad dental mediante el análisis de radiografías panorámicas digitales de pacientes entre 20 a 47 años atendidos en la clínica estomatológica de la Universidad Científica del Sur, (2018 a 2019), Lima-Perú. Se analizaron 289 radiografías panorámicas digitales pertenecientes a individuos de ambos sexos, de 20 a 47 años. Se obtuvo medidas de longitud y anchura en la cámara dental y pulpar en los incisivos centrales superiores. Estos datos se valoraron posteriormente al calcular las proporciones entre la pulpa y longitud de la raíz del incisivo central superior aplicando la fórmula del método de Kvaal et al. para obtener la precisión del método en la estimación de la edad dental. Al aplicar la fórmula de Kvaal et al. indica que la relación entre la anchura de pulpa y la longitud de la raíz presentan un nivel de significancia mayor en relación a otras proporciones: M valor medio de todas las proporciones excepto T (-0.659) y W-L: diferencia entre los valores de W y L (-0.643). El coeficiente de determinación (r²) y el error estándar de la estimación (SEE) utilizando la fórmula original de Kvaal es de r²: 0.70, SEE: 4.90 años, después se propuso una fórmula modificada de Kvaal para la población peruana. El Método de Kvaal et al. tiene una precisión del 1.24 en la estimación de la edad dental de los individuos, utilizando el incisivo central superior en radiografías panorámicas digitales.

Desmineralización de la Dentina Humana Producida por Irrigantes Endodónticos Combinados

El objetivo de este trabajo fue evaluar el efecto de soluciones de irrigación endodónticas solas y combinadas sobre iones calcio y fosfato de la dentina radicular ex vivo. Se emplearon 56 discos de dentina obtenidos del tercio medio radicular de premolares inferiores unirradiculares extraídos por razones ortodóncicas. Los discos se dividieron al azar en 8 grupos (n=7). Grupo I: agua destilada (AD), Grupo II: hipoclorito de sodio (NaClO) 1 %, Grupo III: EDTA 17 %, Grupo IV: ácido maleico (AM) 5 %, Grupo V: ácido acético (AA) 5 %, Grupo VI: EDTA 17 % + NaClO 1 %, Grupo VII: AM 5 % + NaClO 1 %, Grupo VIII: AA 5 % + NaClO 1 %. Los segmentos de dentina permanecieron en contacto a 37° C durante 5 min y 2,5 minutos en cada solución cuando se usaron en forma sucesiva. Se determinó la concentración de iones calcio de las soluciones mediante espectrometría de absorción atómica y la concentración de iones fosfatos mediante colorimetría (Wienner Lab.). Los resultados se expresaron en mg/ml/gr de tejido. Para el análisis estadístico se utilizó ANOVA y Test de Tukey. AA 5 % y EDTA 17 % se comportaron de manera similar utilizados solos durante 5 minutos, NaClO 1 % no mostró diferencias con el AD. AM 5 % eliminó significativamente más calcio y fosfato que todos los grupos. Todas las soluciones desmineralizaron la dentina, pero AM 5 % durante 5 min fue la solución que más afectó el componente inorgánico de la dentina.

The aim of the present study was to evaluate ex vivo irrigating solutions effect under calcium and phosphates dentin ions, using them alone and combined. In this study 56 dentin discs where used. They were obtained from middle third of mandibular single-root premolars extracted for orthodontics reasons. Discs were randomly divided into 8 groups (n:7). Group I: Distilled water (DW), Group II: 1 % sodium hypochlorite (NaOCl), Group III: 17 % EDTA, Group IV: 5 % maleic acid (MA), Group V: 5 % acetic acid (AA), Group VI: 17 % EDTA + 1 % NaOCl, Group VII: 5 % MA + 1 % NaOCl, Group VIII: 5 % AA + 1 % NaOCl. Dentin segments were kept in contact with irrigating solutions at 37°C for 5 minutes, when used alone, or for 2.5 minutes when used combined. After that, calcium ions (using absorption atomic spectrometry) and phosphorus ions (by colorimetry Wienner Lab.) were determined. Results were expressed in mg/ml/g tissue. Statistical analysis was performed by ANOVA and Tukey test. 5 % AA and 17 % EDTA eliminated similar concentrations of calcium and phosphates ions from dentin at 5 minutes exposure time, while 1 % NaOCl did not present statistical differences with control. 5 % MA eliminated significantly more calcium and phosphates ions than the rest of analyzed groups. Every tested solutions demineralized human dentin, but 5 % MA used for 5 minutes did it the most.

Impact of radiotherapy on the morphological and compositional structure of intra-radicular dentin

Abstract Considering the side effects in the oral cavity and dental structures of radiotherapy (RDT) for head and neck cancer, this study aimed to evaluate the effects of RDT on the root dentin concerning the obliteration of dentinal tubules, the inorganic composition of intra-radicular dentin, and the integrity of collagen fibers. Thirty human canines were selected from a biobank and randomly divided into two groups (n=15). The samples were sectioned buccolingually, and a hemisection was used for structural analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Low-vacuum SEM images were obtained at 2000-x magnification to observe the obliteration of the dentinal tubules. Moreover, compositional evaluation was performed using EDS. After RDT, the SEM and EDS analyses were repeated using the same methodology. RDT was applied fractionally at 2 Gy per day, 5 days per week, for 7 weeks, resulting in a total dose of 70 Gy. The collagen integrity of the irradiated and non-irradiated samples was analyzed using Masson's trichrome and picrosirius red staining polarization microscopy. Samples subjected to RDT exhibited dentinal tubule obliteration (p < 0.001); low integrity of type I and III collagen fibers (p < 0.05); compositional reduction of calcium (p = 0.012), phosphorus (p = 0.001), and magnesium (p < 0.001); an increased Ca/P ratio (p < 0.001). RDT affects the structure of dentinal tubules, the inorganic composition of intra-radicular dentin, and the collagen fiber integrity in the root dentin, which may interfere with the effectiveness and durability of dental procedures.

Resumo Considerando os efeitos colaterais na cavidade oral e estruturas dentárias da radioterapia (RDT) para o câncer de cabeça e pescoço, este estudo teve como objetivo avaliar os efeitos da RDT sobre a dentina radicular quanto à obliteração dos túbulos dentinários, a composição inorgânica da dentina intra-radicular e a integridade das fibras colágenas. Trinta caninos humanos foram selecionados de um biobanco e divididos aleatoriamente em dois grupos (n=15). As amostras foram seccionadas no sentido vestíbulo-lingual, e uma hemissecção foi utilizada para análise estrutural por microscopia eletrônica de varredura (MEV) e espectrômetro de raios X de dispersão de energia (EDS). Imagens de MEV de baixo vácuo foram obtidas com aumento de 2500x para observar a obliteração dos túbulos dentinários. Além disso, a avaliação composicional foi realizada usando EDS. Após a RDT, as análises em MEV e EDS foram repetidas usando a mesma metodologia. A RDT foi aplicada fracionada a 2 Gy por dia, 5 dias por semana, durante 7 semanas, resultando em uma dose total de 70 Gy. A integridade do colágeno das amostras irradiadas e não irradiadas foi analisada usando microscopia de polarização de coloração com tricrômio de Masson e picrosirius red. As amostras submetidas a RDT apresentaram obliteração dos túbulos dentinários (p < 0,001); baixa integridade das fibras colágenas tipo I e III (p < 0,05); redução composicional de cálcio (p = 0,012), fósforo (p = 0,001) e magnésio (p < 0,001); e uma relação Ca/P aumentada (p < 0,001). A RDT afeta a estrutura dos túbulos dentinários, a composição inorgânica da dentina intra-radicular e a integridade das fibras colágenas na dentina radicular, o que pode interferir na eficácia e durabilidade dos procedimentos odontológicos.

Clinical implementation of comprehending dentin on a microscopic level

SUMMARY: The aim of the present in vitro study is to visualize dentin to get an in-depth knowledge of the nature of dentin that could provide useful information regarding conditioning dentinal substrate when treating dentinal lesions. Forty-nine extracted human third molars were obtained and prepared to produce artificial dentinal lesions through demineralizing with acetic acid for 7 and 14 days, or lactic acid for 7 days. The teeth were divided into groups and treated with either NaOCl, pepsin, trypsin, or phosphoric acid. To obtain information on the morphology of the treated dentinal surfaces, all samples were visualized under high resolution field emission scanning electron microscope. With high magnification reaching x50000 dentin was clearly visualized together with its constitutes. The effect of various demineralization approaches and various treatment protocols were demonstrated clearly. The relationship between the conditioning procedure steps and the subsequent bond strength was discussed. To our best knowledge, there is no previous clear highly magnified scanning electron microscope images for dentin, and dentinal components and constitutes with and without various treatments. The current in vitro study suggests the complexity nature of dentin as a substrate that should be treated carefully especially with technique sensitive procedures such as adhesive restorations.

El objetivo del presente estudio in vitro fue visualizar la dentina para obtener un conocimiento completo de la naturaleza de ella lo que podría proporcionar información útil sobre el acondicionamiento del sustrato dentinario en el tratamiento de lesiones dentinarias. Se obtuvieron 49 terceros molares humanos extraídos y se prepararon para producir lesiones dentinales artificiales mediante desmineralización con ácido acético por 7 y 14 días, o ácido láctico por 7 días. Los dientes se dividieron en grupos y se trataron con NaOCl, pepsina, tripsina o ácido fosfórico. Para obtener información sobre la morfología de las superficies dentinarias tratadas, todas las muestras se visualizaron bajo un microscopio electrónico de barrido de emisión de campo de alta resolución. Con un gran aumento que alcanzó x50000, la dentina se visualizó claramente junto con sus componentes. Se demostró el efecto de varios enfoques de desmineralización y varios protocolos de tratamiento. Se discutió la relación entre los pasos del procedimiento de acondicionamiento y la subsiguiente fuerza de unión. Hasta donde sabemos, no hay imágenes claras previas de microscopio electrónico de barrido altamente ampliadas para la dentina y los componentes y constituyentes de la dentina con y sin diferentes tratamientos. El estudio in vitro actual sugiere la naturaleza compleja de la dentina como sustrato que debe tratarse con cuidado, especialmente en los procedimientos sensibles a la técnica, tal como las restauraciones adhesivas.