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Despite being able to adhesively restore teeth, adhesives and cement do not possess any anticariogenic protection potential, by which caries recurrence may still occur and reduce the clinical lifetime of adhesive restorations. Several antibacterial agents have been incorporated into dental adhesives and cement to render them anticariogenic. Due to an additional therapeutic effect, such materials are classified as 'dental combination products' with more strict market regulations. We incorporated cetylpyridinium chloride (CPC), often used for oral hygiene applications, into montmorillonite (CPC-Mont), the latter to serve as a carrier for controlled CPC release. CPC-Mont incorporated into tissue conditioner has been approved by the Pharmaceuticals and Medical Devices Agency (PmontMDA) in Japan. To produce a clinically effective dental cement with the antibacterial potential to prevent secondary caries, we incorporated CPC-Mont into PMMA resin cement. We measured the flexural strength, shear bond strength onto dentin, CPC release, and the biofilm-inhibition potential of the experimental CPC-Mont-containing PMMA cement. An 8 and 10 wt% CPC-Mont concentration revealed the antibacterial potential without reducing the mechanical properties of the PMMA cement.

Despite being able to adhesively restore teeth, adhesives and cement do not possess any anticariogenic protection potential, by which caries recurrence may still occur and reduce the clinical lifetime of adhesive restorations. Several antibacterial agents have been incorporated into dental adhesives and cement to render them anticariogenic. Due to an additional therapeutic effect, such materials are classified as 'dental combination products' with more strict market regulations. We incorporated cetylpyridinium chloride (CPC), often used for oral hygiene applications, into montmorillonite (CPC-Mont), the latter to serve as a carrier for controlled CPC release. CPC-Mont incorporated into tissue conditioner has been approved by the Pharmaceuticals and Medical Devices Agency (PmontMDA) in Japan. To produce a clinically effective dental cement with the antibacterial potential to prevent secondary caries, we incorporated CPC-Mont into PMMA resin cement. We measured the flexural strength, shear bond strength onto dentin, CPC release, and the biofilm-inhibition potential of the experimental CPC-Mont-containing PMMA cement. An 8 and 10 wt% CPC-Mont concentration revealed the antibacterial potential without reducing the mechanical properties of the PMMA cement.

Naito K., Kuwahara Y., Yamamoto H., et al. Improvement of acid resistance of Zn-doped dentin by newly generated chemical bonds. Materials and Design, 215, 110412. https://doi.org/10.1016/j.matdes.2022.110412., Dental caries, the world's most prevalent infectious disease, is caused by the diffusion of hydroxyl ions into tooth structures. To prevent dental caries, the application of fluoride (F) and zinc (Zn) ions to teeth surfaces are potential effective measures. In this study, The ionic influence, especially the chemical bond of F and Zn, on the acid resistance of dentin were investigated by particle induced X-ray / gamma-ray emission, X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The results showed Zn was distributed in the limited surface layer of dentin without altering its crystal structure. From the Zn K edge extended X-ray absorption fine structure, Zn incorporated into dentin was surrounded by oxygen and demonstrated four-fold coordination. The bond length and chemical state of Zn–O in Zn doped dentin suggested newly generated Zn–O covalent bond, which may improve acid resistance of dentin. This study showed that the atomic and molecular structures, such as the molecular distances and chemical state, influenced acid resistance of teeth, emphasizing the validity of chemical state analysis for understanding properties in biomaterials.

Objectives: To implement a dentin slice model of mesenchymal stem cells derived from dental tissues in a fibrin-agarose construct for dental pulp regeneration. Material and Methods: MSCs derived from different oral cavity tissues were combined with a fibrin-agarose construct at standard culture conditions. Cell viability and proliferation tests were assayed using a fluorescent cell dye Calcein/Am and WST-1 kit. The proliferation assay was evaluated at 24, 48, 72, and 96 hours. Also, we assessed the dental pulp stem cells (DPSCs) cell morphology inside the construct with histological stains such as Hematoxylin and Eosin, Masson's trichrome, and Periodic acid–Schiff. In addition, we elaborated a tooth dentin slice model using a culture of DPSC in the fibrin–agarose constructs co-adhered to dentin walls. Results: The fibrin-agarose construct was a biocompatible material for MSCs derived from dental tissues. It provided good conditions for MSCs' viability and proliferation. DPSCs proliferated better than the other MSCs, but the data did not show significant differences. The morphology of DPSCs inside the construct was like free cells. The dentin slice model was suitable for DPSCs in the fibrin-agarose construct. Conclusion: Our findings support the dentin slice model for future biological use of fibrin-agarose matrix in combination with DPSCs and their potential use in dental regeneration. The multipotency, high proliferation rates, and easy obtaining of the DPSCs make them an attractive source of MSCs for tissue regeneration., Objetivos: Implementar un modelo de dentina con células madre mesenquimales derivadas de tejidos dentales en una constructo de fibrina-agarosa para la regeneración de la pulpa dental. Material y Métodos: Las MSC derivadas de diferentes tejidos de la cavidad oral se combinaron con una construcción de fibrina-agarosa en condiciones de cultivo estándar. Las pruebas de viabilidad y proliferación celular se ensayaron utilizando un kit de colorante celular fluorescente Calcein/Am y WST-1. El ensayo de proliferación se evaluó a las 24, 48, 72 y 96 horas. Además, evaluamos la morfología celular de las células madre de la pulpa dental (DPSC) dentro de la construcción con tinciones histológicas como hematoxilina y eosina, tricrómico de Masson y ácido peryódico de Schiff. Además, elaboramos un modelo de rebanadas de dentina dental utilizando un cultivo de DPSC en las construcciones de fibrina-agarosa coadheridas a las paredes de la dentina. Resultados: La construcción de fibrina-agarosa fue un material biocompatible para las MSC derivadas de tejidos dentales. Proporcionó buenas condiciones para la viabilidad y proliferación de las MSC. Las DPSC proliferaron mejor que las otras MSC, pero los datos no mostraron diferencias significativas. La morfología de las DPSC dentro de la construcción era como la de las células libres. El modelo de corte de dentina fue adecuado para DPSC en la construcción de fibrina-agarosa. Conclusión: Nuestros hallazgos respaldan el modelo de corte de dentina para el futuro uso biológico de la matriz de fibrina-agarosa en combinación con DPSC y su uso potencial en la regeneración dental. El multipotencial, las altas tasas de proliferación y la fácil obtención de las DPSC las convierten en una fuente atractiva de MSC para la regeneración de tejidos

Background: This study evaluated the effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots. Material and Methods: Sixty-four roots of extracted human maxillary canines were weakened, prepared and filled with two different endodontic sealers (Endofill and AH Plus). In half of the sample, set aside for each respective sealer, excess filling material was cleaned. In the other half, the weakened areas were not cleaned, and the excess of sealer was spread on the intraradicular dentin. Intentionally worn areas inside each root were restored with a microhybrid light-cure composite resin (Z100) to reinforce them, with and without acid etching. Prefabricated metal posts were fixed with a dual resin cement (RelyX ARC), and the specimens were submitted to a pull-out test. Statistical analysis was performed by means of Shapiro-Wilk, analysis of variance (one-way ANOVA) and Tukey-Kramer tests (p<0.05). Results: The groups filled with Endofill (GI, GII, GIII, GIV) had the lowest bond strength values, which were similar among each other (p>0.05).The greatest bond strength values were observed in roots filled with AH Plus (GV, GVI, GVII, GVIII), mainly without cleaning of the weakened areas, and followed by acid etching (GVII), and also with cleaning of the weakened areas, however, with no acid etching (GVI) (p<0.05). Conclusion: The greatest bond strength values were observed in roots filled with AH Plus; (1) without cleaning of the weakened areas and with acid etching, and; (2) with cleaning of the weakened areas, but without acid etching., Antecedentes: este estudio evaluó los efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar las raíces debilitadas.Material y Métodos: Sesenta y cuatro raíces de caninos maxilares humanos extraídos fueron debilitadas, preparadas y rellenadas con dos selladores endodónticos diferentes (Endofill y AH Plus). En la mitad de la muestra, reservada para cada sellador respectivo, se limpió el exceso de material de relleno. En la otra mitad, las áreas debilitadas no se limpiaron y el exceso de sellador se esparció sobre la dentina intrarradicular. Las áreas desgastadas intencionalmente dentro de cada raíz se restauraron con una resina compuesta fotopolimerizable microhíbrida (Z100) para reforzarlas, con y sin grabado ácido. Los postes metálicos prefabricados se fijaron con un cemento de resina dual (RelyX ARC) y los especímenes se sometieron a una prueba de extracción. El análisis estadístico se realizó mediante Shapiro-Wilk, análisis de varianza (ANOVA de una vía) y pruebas de Tukey-Kramer (p<0,05).Resultados: Los grupos rellenos con Endofill (GI, GII, GIII, GIV) presentaron los valores más bajos de fuerza de unión, los cuales fueron similares entre sí (p>0,05). Los mayores valores de fuerza de unión se observaron en raíces rellenas con AH Plus (GV , GVI, GVII, GVIII), principalmente sin limpieza de las áreas debilitadas, seguido de grabado ácido (GVII), y también con limpieza de las áreas debilitadas aunque sin grabado ácido (GVI) (p<0.05).Conclusión: Los mayores valores de fuerza de unión se observaron en las raíces rellenas con AH Plus; (1) sin limpieza de las áreas debilitadas y con grabado ácido, y; (2) con limpieza de las áreas debilitadas, pero sin grabado ácido.

Onlay bone augmentation is a challenging field, especially in esthetic zones. In implant dentistry, labial bone loss is generally recovered through autologous bone and/or biomaterials. Dental pioneers have been applying a patient-own demineralized dentin matrix (DDM) for bone regeneration. The aim of this study was to histologically and radiologically evaluate horizontal bone augmentation on an anterior atrophic maxilla using an autograft of non-vital tooth-derived DDM for implant. A 56-year-old female patient presented with severe labial bone loss. Autologous DDM was immediately prepared for horizontal ridge augmentation. DDM blocks were fixed with titanium screws for lateral augmentation. DDM granules were grafted on the atrophic bone between the DDM blocks. Twelve months postoperatively, bone biopsy was performed from the implant placement point for histological observation. X-ray computed tomography (CT) was performed before and after the DDM graft surgery. Hematoxylin and eosin sections showed that new bones were directly generated on the DDM residue. CT images showed the original buccal bone lines and root-type and wall-type DDM. The grafted DDMs were clearly found on the original bone. The outlines in the 22nd region indicated an 8.11 mm horizontal width after the implant placements compared to 4.95 mm before the augmentation. Additionally, the width at the upper level increased from 3.38 mm to 5.92 mm. DDM scaffolds contributed to the horizontal bony support required to place the implants. The patient experienced therapeutic success with DDM immediate autograft and implant surgery.

A simple, area-specific coating technique for fluoridated apatite (FAp) on teeth would be useful in dental applications. Recently, we achieved area-specific FAp coating on a human dentin substrate within 30 min by a laser-assisted biomimetic (LAB) process; pulsed Nd:YAG laser irradiation in a fluoride-containing supersaturated calcium phosphate solution (FCP solution). The LAB-processed, FAp-coated dentin substrate exhibited antibacterial activity against a major oral bacterium, Streptococcus mutans. In the present study, we refined the LAB process with a combination of a dental diode laser and a clinically approved light-absorbing molecule, indocyanine green (ICG). A micron-thick FAp layer was successfully formed on the dentin surface within only 3 min by the refined LAB process, i.e., dental diode laser irradiation in the FCP solution following ICG treatment. The ICG layer precoated on the dentin substrate played a crucial role in inducing rapid pseudo-biomineralization (FAp layer formation) on the dentin surface by absorbing laser light at the solid-liquid interface. In the refined LAB process, the precoated ICG layer was eliminated and replaced with the newly formed FAp layer composed of vertically oriented pillar-like nanocrystals. Cross-sectional ultrastructural analysis revealed a smooth interface between the FAp layer and the dentin substrate. The refined LAB process has potential as a tool for the tooth surface functionalization and hence, is worth further process refinement and in vitro and in vivo studies.

Background: This study has been conducted to evaluate the dentin regeneration potential as an autologous graft material for the preservation of the bone volume in the post-extraction socket. Tooth Transformer has been used as the device required to demineralize the dentin got from the extracted elements, which led to obtaining a granular material rich in collagen and growth factors. Methods: All 8 patients selected for the study underwent two surgical procedures. During the first surgery, the affected elements have been extracted, the Tooth Transformer protocol has been run, and the material has been grafted into the existing bone defects and post-extraction socket. After three months, the biopsy of the regenerated areas has been performed and the implants required for prosthetic rehabilitation were placed in the same site. For two of the 8 patients, the implant has been placed with the support of a surgical guide. Result: CBCT and histological analysis’ results after 3 months confirmed the actual replacement of grafted material and the regeneration of bone tissue suitable for implant rehabilitation. Conclusion: Thus, the Tooth Transformer proves to be an effective device to produce an innovative autologous material from dentin, which is capable of predictable viable bone tissue regeneration able to support prosthetic implant rehabilitation in edentulous sites.

Onlay bone augmentation is a challenging field, especially in esthetic zones. In implant dentistry, labial bone loss is generally recovered through autologous bone and/or biomaterials. Dental pioneers have been applying a patient-own demineralized dentin matrix (DDM) for bone regeneration. The aim of this study was to histologically and radiologically evaluate horizontal bone augmentation on an anterior atrophic maxilla using an autograft of non-vital tooth-derived DDM for implant. A 56-year-old female patient presented with severe labial bone loss. Autologous DDM was immediately prepared for horizontal ridge augmentation. DDM blocks were fixed with titanium screws for lateral augmentation. DDM granules were grafted on the atrophic bone between the DDM blocks. Twelve months postoperatively, bone biopsy was performed from the implant placement point for histological observation. X-ray computed tomography (CT) was performed before and after the DDM graft surgery. Hematoxylin and eosin sections showed that new bones were directly generated on the DDM residue. CT images showed the original buccal bone lines and root-type and wall-type DDM. The grafted DDMs were clearly found on the original bone. The outlines in the 22nd region indicated an 8.11 mm horizontal width after the implant placements compared to 4.95 mm before the augmentation. Additionally, the width at the upper level increased from 3.38 mm to 5.92 mm. DDM scaffolds contributed to the horizontal bony support required to place the implants. The patient experienced therapeutic success with DDM immediate autograft and implant surgery.

A simple, area-specific coating technique for fluoridated apatite (FAp) on teeth would be useful in dental applications. Recently, we achieved area-specific FAp coating on a human dentin substrate within 30 min by a laser-assisted biomimetic (LAB) process; pulsed Nd:YAG laser irradiation in a fluoride-containing supersaturated calcium phosphate solution (FCP solution). The LAB-processed, FAp-coated dentin substrate exhibited antibacterial activity against a major oral bacterium, Streptococcus mutans. In the present study, we refined the LAB process with a combination of a dental diode laser and a clinically approved light-absorbing molecule, indocyanine green (ICG). A micron-thick FAp layer was successfully formed on the dentin surface within only 3 min by the refined LAB process, i.e., dental diode laser irradiation in the FCP solution following ICG treatment. The ICG layer precoated on the dentin substrate played a crucial role in inducing rapid pseudo-biomineralization (FAp layer formation) on the dentin surface by absorbing laser light at the solid-liquid interface. In the refined LAB process, the precoated ICG layer was eliminated and replaced with the newly formed FAp layer composed of vertically oriented pillar-like nanocrystals. Cross-sectional ultrastructural analysis revealed a smooth interface between the FAp layer and the dentin substrate. The refined LAB process has potential as a tool for the tooth surface functionalization and hence, is worth further process refinement and in vitro and in vivo studies.

Naito K., Kuwahara Y., Yamamoto H., et al. Improvement of acid resistance of Zn-doped dentin by newly generated chemical bonds. Materials and Design, 215, 110412. https://doi.org/10.1016/j.matdes.2022.110412., Dental caries, the world's most prevalent infectious disease, is caused by the diffusion of hydroxyl ions into tooth structures. To prevent dental caries, the application of fluoride (F) and zinc (Zn) ions to teeth surfaces are potential effective measures. In this study, The ionic influence, especially the chemical bond of F and Zn, on the acid resistance of dentin were investigated by particle induced X-ray / gamma-ray emission, X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The results showed Zn was distributed in the limited surface layer of dentin without altering its crystal structure. From the Zn K edge extended X-ray absorption fine structure, Zn incorporated into dentin was surrounded by oxygen and demonstrated four-fold coordination. The bond length and chemical state of Zn–O in Zn doped dentin suggested newly generated Zn–O covalent bond, which may improve acid resistance of dentin. This study showed that the atomic and molecular structures, such as the molecular distances and chemical state, influenced acid resistance of teeth, emphasizing the validity of chemical state analysis for understanding properties in biomaterials.

In our work, the influence of the coordination environment of the Ca atom states in biomimetic mineralizing composite dental materials integrated with dental tissue was investigated. Biomimetic composites as well as natural dental tissue samples were investigated using synchrotron X-ray absorption near edge structure (XANES) spectroscopy. Energy structure studies revealed a number of important features related to the different type of calcium atom environment. the surface of nanocrystalline calcium carbonate-substituted hydroxyapatite (nano-cHAp) crystals in natural enamel and dentin involved in the formation of bonds with the organic matrix is more characterized by the coordination environment of the calcium atom corresponding to its location in the CaI position, i.e. bound through common oxygen atoms with PO4 tetrahedrons. At the same time, on the surface of nano-cHAp crystals in bioinspired dental materials, the calcium atom is more characteristically located in the CaII position, bound to the hydroxyl OH group. The detected features in the coordination atomic environment in nano-cHAp play a fundamental role for engineering a biomimetic dental composite of the natural organomineral interaction in the mineralized tissue. © 2022 The Authors.

Onlay bone augmentation is a challenging field, especially in esthetic zones. In implant dentistry, labial bone loss is generally recovered through autologous bone and/or biomaterials. Dental pioneers have been applying a patient-own demineralized dentin matrix (DDM) for bone regeneration. The aim of this study was to histologically and radiologically evaluate horizontal bone augmentation on an anterior atrophic maxilla using an autograft of non-vital tooth-derived DDM for implant. A 56-year-old female patient presented with severe labial bone loss. Autologous DDM was immediately prepared for horizontal ridge augmentation. DDM blocks were fixed with titanium screws for lateral augmentation. DDM granules were grafted on the atrophic bone between the DDM blocks. Twelve months postoperatively, bone biopsy was performed from the implant placement point for histological observation. X-ray computed tomography (CT) was performed before and after the DDM graft surgery. Hematoxylin and eosin sections showed that new bones were directly generated on the DDM residue. CT images showed the original buccal bone lines and root-type and wall-type DDM. The grafted DDMs were clearly found on the original bone. The outlines in the 22nd region indicated an 8.11 mm horizontal width after the implant placements compared to 4.95 mm before the augmentation. Additionally, the width at the upper level increased from 3.38 mm to 5.92 mm. DDM scaffolds contributed to the horizontal bony support required to place the implants. The patient experienced therapeutic success with DDM immediate autograft and implant surgery.

Considerable amount of research has been focused on dentin mineralization, odontoblast differentiation, and their application in dental tissue engineering. However, very little is known about the differential role of functionally and spatially distinct types of dental epithelium during odontoblast development. Here we show morphological and functional differences in dentin located in the crown and roots of mouse molar and analogous parts of continuously growing incisors. Using a reporter (DSPP-cerulean/DMP1-cherry) mouse strain and mice with ectopic enamel (Spry2(+/-);Spry4(-/-)), we show that the different microstructure of dentin is initiated in the very beginning of dentin matrix production and is maintained throughout the whole duration of dentin growth. This phenomenon is regulated by the different inductive role of the adjacent epithelium. Thus, based on the type of interacting epithelium, we introduce more generalized terms for two distinct types of dentins: cementum versus enamel-facing dentin. In the odontoblasts, which produce enamel-facing dentin, we identified uniquely expressed genes (Dkk1, Wisp1, and Sall1) that were either absent or downregulated in odontoblasts, which form cementum-facing dentin. This suggests the potential role of Wnt signalling on the dentin structure patterning. Finally, we show the distribution of calcium and magnesium composition in the two developmentally different types of dentins by utilizing spatial element composition analysis (LIBS). Therefore, variations in dentin inner structure and element composition are the outcome of different developmental history initiated from the very beginning of tooth development. Taken together, our results elucidate the different effects of dental epithelium, during crown and root formation on adjacent odontoblasts and the possible role of Wnt signalling which together results in formation of dentin of different quality. (c) 2021 The Authors. Journal of Bone and Mineral Research published by

Considerable amount of research has been focused on dentin mineralization, odontoblast differentiation, and their application in dental tissue engineering. However, very little is known about the differential role of functionally and spatially distinct types of dental epithelium during odontoblast development. Here we show morphological and functional differences in dentin located in the crown and roots of mouse molar and analogous parts of continuously growing incisors. Using a reporter (DSPP-cerulean/DMP1-cherry) mouse strain and mice with ectopic enamel (Spry2(+/-);Spry4(-/-)), we show that the different microstructure of dentin is initiated in the very beginning of dentin matrix production and is maintained throughout the whole duration of dentin growth. This phenomenon is regulated by the different inductive role of the adjacent epithelium. Thus, based on the type of interacting epithelium, we introduce more generalized terms for two distinct types of dentins: cementum versus enamel-facing dentin. In the odontoblasts, which produce enamel-facing dentin, we identified uniquely expressed genes (Dkk1, Wisp1, and Sall1) that were either absent or downregulated in odontoblasts, which form cementum-facing dentin. This suggests the potential role of Wnt signalling on the dentin structure patterning. Finally, we show the distribution of calcium and magnesium composition in the two developmentally different types of dentins by utilizing spatial element composition analysis (LIBS). Therefore, variations in dentin inner structure and element composition are the outcome of different developmental history initiated from the very beginning of tooth development. Taken together, our results elucidate the different effects of dental epithelium, during crown and root formation on adjacent odontoblasts and the possible role of Wnt signalling which together results in formation of dentin of different quality. (c) 2021 The Authors. Journal of Bone and Mineral Research published by

Silver diamine fluoride (SDF) is a dental biomaterial used to arrest dental caries. To better understand SDF's mechanism of action, we examined the localization of silver within the tissues of SDF-treated teeth. Carious primary teeth fixed within 2 min of SDF application (SDF-minutes, n = 3), at 3 wk after SDF application in vivo (SDF-weeks, n = 4), and at 2 y after multiple SDF applications in vivo (SDF-multiple, n = 1) were investigated in this study. Carious primary teeth without SDF application (no-SDF, n = 3) served as controls. Mineral density and structural analyses were performed via micro-X-ray computed tomography and scanning electron microscopy. Elemental analyses were performed through X-ray fluorescence microprobe and energy-dispersive X-ray spectroscopic techniques. SDF-treated teeth revealed higher X-ray-attenuated surface and subsurface regions within carious lesions, and similar regions were not present in no-SDF teeth. Regions of higher mineral density correlated with regions of silver abundance in SDF-treated teeth. The SDF penetration depth was approximated to 0.5 ± 0.02 mm and 0.6 ± 0.05 mm (mean ± SD) for SDF-minutes and SDF-weeks specimens, respectively. A higher percentage of dentin tubular occlusion by silver or calcium phosphate particles was observed in primary teeth treated with SDF-weeks as compared with SDF-minutes. Elemental analysis also revealed zinc abundance in carious lesions and around the pulp chamber. SDF-weeks teeth had significantly increased tertiary dentin than SDF-minutes and no-SDF teeth. These results suggest that SDF treatment on primary teeth affected by caries promotes pathologic biomineralization by altering their physicochemical properties, occluding dentin tubules, and increasing tertiary dentin volume. These seemingly serendipitous effects collectively contribute to the cariostatic activity of SDF.

The complex, dynamic, and hydrated microstructures of human dentin serve as the major determinant for the restorative performance of biomaterials. This study aimed to evaluate the mechanical properties of human dentin under different hydration conditions. The occlusal dentin of five third molars was exposed and cut into 1 mm(2) dentin slabs. The slabs were then polished and further cut into 1 mm(2) dentin beams and stored in distilled water. Two beams/tooth were used for testing their hardness (H) and elastic modulus (E) at 5 min (baseline), 1 h, and 24 h after dehydration (23 degrees C and 30% RH), and also for measuring weight at following dehydration times: 0 min, 5 min, 1 h, and 24 h. Five additional molars were employed to prepare 0.4 mm(2) dentin beams (3/tooth) for determining ultimate tensile strength (UTS) at 5 min (baseline), 1 h, and 24 h post-dehydration. Statistical significance was set at alpha = 0.05. Dehydration time significantly affected H, E, weight-loss, and UTS of dentin (p < 0.05). H and E values showed a strongly positive and significant correlation (r > 0.5, p < 0.05). Dehydration can substantially modify the mechanical properties of dentin, leading to misinterpretation of restorative outcomes in vitro.

Zinc-fluoride glass nanoparticles (Zinc-F) release several ions, such as fluoride, zinc and calcium ions, through acid-base reactions. The aim of this study was to evaluate the antibacterial and cytotoxic properties of Zinc-F. Antibacterial tests showed that a Zinc-F eluting solution significantly reduced the turbidity and colony-forming units of Streptococcus mutans and Actinomyces naeslundii, compared to that of calcium-fluoroaluminosilicate glass nanoparticles without zinc ions. In live/dead staining, Zinc-F eluate significantly decreased green-stained bacterial cells, indicating live cells, compared with the control (no application). Human dentin coated with Zinc-F showed suppressed S. mutans and A. naeslundii biofilm formation. Additionally, Zinc-F eluate showed low cytotoxic effects in osteoblastic and fibroblastic cells. Therefore, our findings suggested that Zinc-F exhibits antibacterial and biocompatible properties through multiple-ion release.

Dental caries is one of the most common diseases in the world, and global incidence rates are increasing. The early detection of dental lesions enables a conservative approach to be employed and represents a priority in modern dentistry. Recent studies have suggested that conventional diagnostic methods, such as visual tactile inspection and X-ray examination, exhibit low sensitivity and are not very effective in early diagnoses. Consequently, late detection of decay is associated with an increased loss of tooth structure. New diagnostic systems based on optical properties have been developed to facilitate early detection. Several studies have evaluated the performance of near-infrared imaging (NIRI) as an early diagnostic tool. NIRI using light ranging from 700 to 1700 nm has demonstrated better optical properties compared to conventional optical systems using light in the visible spectra. NIRI enables deeper penetration of the light in the tooth tissue, weak scattering with lower background noise and strong photon absorption with detailed images. Several in-vivo studies have demonstrated that NIRI technology has the potential to improve performance compared with current diagnostic methods. NIRI exhibits increased sensitivity compared to radiographs and is more suitable to identify approximal enamel lesions. This paper aimed to review these recent advances and their potential applications in daily clinical practice.

The complex, dynamic, and hydrated microstructures of human dentin serve as the major determinant for the restorative performance of biomaterials. This study aimed to evaluate the mechanical properties of human dentin under different hydration conditions. The occlusal dentin of five third molars was exposed and cut into 1 mm(2) dentin slabs. The slabs were then polished and further cut into 1 mm(2) dentin beams and stored in distilled water. Two beams/tooth were used for testing their hardness (H) and elastic modulus (E) at 5 min (baseline), 1 h, and 24 h after dehydration (23 degrees C and 30% RH), and also for measuring weight at following dehydration times: 0 min, 5 min, 1 h, and 24 h. Five additional molars were employed to prepare 0.4 mm(2) dentin beams (3/tooth) for determining ultimate tensile strength (UTS) at 5 min (baseline), 1 h, and 24 h post-dehydration. Statistical significance was set at alpha = 0.05. Dehydration time significantly affected H, E, weight-loss, and UTS of dentin (p < 0.05). H and E values showed a strongly positive and significant correlation (r > 0.5, p < 0.05). Dehydration can substantially modify the mechanical properties of dentin, leading to misinterpretation of restorative outcomes in vitro.

Aim: To introduce a methodology designed to simultaneously visualize dental ultrastructures, including cellular and soft tissue components, by utilizing phosphotungstic acid (PTA) as a contrast-enhancement agent. Methodology: Sound third molars were collected from healthy human adults and fixed in 4% buffered paraformaldehyde. To evaluate the impact of PTA in concentrations of 0.3%, 0.7% and 1% on dental soft and hard tissues for CT imaging, cementum and dentine-pulp sections were cut, dehydrated and stained with immersion periods of 12, 24 h, 2 days or 5 days. The samples were scanned in a high-resolution nano-CT device using pixel sizes down to 0.5 µm to examine both the cementum and pulpal regions. Results: Dental cementum and periodontium as well as odontoblasts and predentine were made visible through PTA staining in high-resolution three-dimensional nano-CT scans. Different segments of the tooth required different staining protocols. The thickness of the cementum could be computed over the length of the tooth once it was made visible by the PTA-enhanced contrast, and the attached soft tissue components of the interior of the tooth could be shown on the dentine-pulp interface in greater detail. Three-dimensional illustrations allowed a histology-like visualization of the sections in all orientations with a single scan and easy sample preparation. The segmentation of the sigmoidal dentinal tubules and the surrounding dentine allowed a three-dimensional investigation and quantitative of the dentine composition, such as the tubular lumen or the ratio of the tubular lumen area to the dentinal surface. Conclusion: The staining protocol made it possible to visualize hard tissues along with cellular layers and soft tissues in teeth using a laboratory-based nano-CT technique. The protocol depended on both tissue type and size. This methodology offers enhanced possibilities for the concomitant visualization of soft and hard dental tissues. © 2021 The Authors. Internatio

This paper focuses on the analysis and quantitative characterization of the effect of saturation on the viscoelastic properties of human root dentin. Uniaxial compression tests under creep conditions have been performed on root molar dentin with tubules fully saturated with a viscous physiological fluid, as well as samples with non-saturated tubules (dry dentin samples). Blair-Rabotnov (BR) fraction-exponential model is used to characterize the overall viscoelastic properties of dentin and correlate them to the level of saturation. Experimental data are compared with theoretical predictions that interrelate the viscoelastic properties of saturated and dry specimens. The results show that saturation increases the viscous creep strains of dentin, which indicates a reduced capacity for stress relief. The uniaxial compression test under creep conditions, in combination with the BR kernel model, allows us to analyze the creep-relaxation behavior of dentin. © 2020 Elsevier Ltd.

In the present work, a biomaterial (SBA-16/HA) based on the growth of hydroxyapatite (HA) particles within an organized silica structure SBA-16 (Santa Barbara Amorphous-16) was developed to evaluate its application to act as a porous microenvironment promoting attachment and viability of human dental pulp stem cells of healthy deciduous teeth (SHED). First, SHED were isolated and their phenotypes were evaluated by flow cytometry. The samples of SBA-16/HA were characterized by X-ray diffraction (XRD), small and wide angle X-ray scattering (SWAXS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) equipped with energy dispersive spectra detector (EDS). Afterward, cells were cultured in the eluates of the above-mentioned biomaterial aged for 24 hr, 7. and 14 days. Bio-Oss (R) and dentin particles are involved for comparison and cells are cultured in the eluates of these two materials also. Thiazolyl Blue Tetrazolium bromide assay-MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide assay) was used for the determination of cell viability. The results obtained by all aforementioned characterization methods of SBA-16/HA, revealed a uniform spherical mesoporous structure, an intrinsic characteristic of this material. This material displayed excellent biocompatibility on SHEDs, and even proliferative potential, indicating that SBA-16/HA could potentially serve as a suitable substrate for bone regeneration. Contrary to SBA-16/HA, dentin particles showed low cytotoxicity at all time points, compared to control and Bio-Oss (R) groups. Our results substantiate the idea that SBA-16/HA has a beneficial effect on SHEDs, thus paving the way toward developing new material for bone replacement.

BACKGROUND: Traditionally, cavitated carious lesions and those extending into dentine have been treated by 'complete' removal of carious tissue, i.e. non-selective removal and conventional restoration (CR). Alternative strategies for managing cavitated or dentine carious lesions remove less or none of the carious tissue and include selective carious tissue removal (or selective excavation (SE)), stepwise carious tissue removal (SW), sealing carious lesions using sealant materials, sealing using preformed metal crowns (Hall Technique, HT), and non-restorative cavity control (NRCC).OBJECTIVES: To determine the comparative effectiveness of interventions (CR, SE, SW, sealing of carious lesions using sealant materials or preformed metal crowns (HT), or NRCC) to treat carious lesions conventionally considered to require restorations (cavitated or micro-cavitated lesions, or occlusal lesions that are clinically non-cavitated but clinically/radiographically extend into dentine) in primary or permanent teeth with vital (sensitive) pulps.SEARCH METHODS: An information specialist searched four bibliographic databases to 21 July 2020 and used additional search methods to identify published, unpublished and ongoing studies. SELECTION CRITERIA: We included randomised clinical trials comparing different levels of carious tissue removal, as listed above, against each other, placebo, or no treatment. Participants had permanent or primary teeth (or both), and vital pulps (i.e. no irreversible pulpitis/pulp necrosis), and carious lesions conventionally considered to need a restoration (i.e. cavitated lesions, or non- or micro-cavitated lesions radiographically extending into dentine). The primary outcome was failure, a composite measure of pulp exposure, endodontic therapy, tooth extraction, and restorative complications (including resealing of sealed lesions).DATA COLLECTION AND ANALYSIS: Pairs of review authors independently screened search results, extracted

Introduction: The incidence of vertical root fracture in endodontically treated teeth increases with patient age. This study evaluated the microstructure, chemical composition, and mechanical properties of radicular dentin as a function of aging. Methods: Single-rooted teeth were obtained from adult donors ranging from age 15 to older than 80 years. Beams were extracted from the middle third of the root and subjected to 4-point flexure to failure to evaluate strength of dentin in terms of donor age. Based on the strength distribution, the fatigue strength of root tissue from young (<= 30 years) and old (>= 55 years) donor teeth was evaluated via cyclic flexure loading. The microstructure and chemical composition of radicular dentin from the 2 groups were evaluated as a function of distance from the root apex using microscopy and Raman spectroscopy, respectively. Results: The strength decreased with age by approximately 25 MPa per decade, which resulted in a significant difference (P <= .0001) between the young (199 +/- 36 MPa) and old (122 +/- 11 MPa) groups. There was also a significant difference (P <= .0001) in fatigue strength between the young and old age groups. Both the mineral-to-collagen ratio and degree of cross-linking increased with age, with the largest changes identified in the apical and middle thirds, respectively. Conclusions: There is a reduction in the damage tolerance of radicular dentin with increasing age. This degradation appears to result from changes in the microstructure, corresponding chemical composition, and increase in collagen cross-linking with age, and is most severe near the root apex.

Objective: This study aimed to identify the changes in the time-dependent deformation response of coronal dentin with ageing and its relationship with changes in chemical composition. Background: The structural behaviour of dentin with ageing is affected by changes in the density and diameter of its dentinal tubules (ie porosity), as well as changes in chemical composition throughout the tooth. However, little is known about the time-dependent deformation behaviour of aged dentin and the importance of its hierarchical structure and variations in chemical composition. Materials and methods: The spherical indentation response of aged coronal dentin was analysed in the outer, middle and inner regions, and its time-dependent deformation response was modelled in terms of its microstructure and chemical composition using a model recently proposed for young dentin. Results: The viscous deformation behaviour of aged dentin followed a power-law response with a decrease in the stress exponent when compared to young dentin. These results can be explained by cross-linking of the collagen present in the tissue. Conclusion: A decrease in the deformation ability of aged dentin was found. This behaviour could be a result of a dissolution process and reprecipitation of the minerals present in intertubular dentin into the dentinal tubules. © 2018 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd

Objective: Understanding the effects of biological aging on human tissues has been a topic of extensive research. With the increase in healthy seniors and quality of life that topic is becoming increasingly important. In this investigation the effects of aging on the microstructure, chemical composition and hardness of human coronal dentin was studied from a comparison of teeth within ``young'' and ``old'' age groups. Methods: The microstructure of dentin within three regions (i.e., inner, middle and outer) was analyzed using electron and optical microscopy. The mineral-to-collagen ratio in these three regions was estimated using Raman spectroscopy and the hardness was evaluated using microindentation. Results: Results showed that there were significant differences in tubule density, tubule diameter and peritubular cuff diameter with depth. Although there was no difference in tubule density and diameter of the tubules between the age groups, there was a significant difference in the occlusion ratio. A significant increase in hardness between young and old patients was found for middle and outer dentin. An increase in mineral-to-collagen ratio from inner to outer dentin was also found for both groups. In old patients, an increase in mineral content was found in outer coronal dentin as a consequence of tubule occlusion. Conclusions: An increase in occlusion ratio, hardness, and mineral content was found in the dentin of adult patients with age. This increase is most evident in the outer coronal dentin. (C) 2015 Elsevier Ltd. All rights reserved.

Objective The viscoelastic behavior of dentin and its ability to undergo time dependent deformation are considered to be important to oral functions and its capacity to resist fracture. There are spatial variations in the microstructure of dentin within the crown, which could be important to the viscous behavior. However, a spatially resolved description for the viscoelastic behavior of coronal dentin has not been reported. Methods In this investigation spherical indentations were made in three regions of coronal dentin including the outer, middle and inner regions. Power law relations were developed to quantitatively describe the stress-strain responses of the tissue. Results Results showed that the deformation behavior was strongly dependent on the composition (mineral to collagen ratio) and microstructure (tubule density), which contributed to an increase in the rate of viscous deformation with increasing proximity to the pulp. Conclusions A model accounting for spatial variations in composition and microstructure was developed to describe the steady-state time dependent deformation behavior of coronal dentin, and a good agreement was found with the experimental results. © 2017 Elsevier Ltd

Objective: The fracture toughness of dentin is critical to the prevention of tooth fracture. Within the tooth crown, the mechanical properties of dentin are influenced by spatial variations in the density and diameter of the dentin tubules with distance from the pulp. There are also relevant changes to the microstructure of dentin with age. In this investigation the importance of tubule density to the fracture toughness of dentin was evaluated in ``young'' and ``old'' age groups. Methods: The variations in microstructure (density and diameter of tubules) from young and old donor teeth were studied by means of optical microscopy. Results: A reduction in the density and diameter of tubules was identified to occur with aging. An approach previously proposed to study the mechanical behavior of porous materials was used to model the fracture toughness of coronal dentin in terms of the tubule characteristics. Results were then compared with published results from previous studies. Conclusions: The model predictions were consistent with experimental results for the fracture toughness of dentin from young donor teeth, but overestimated the values that have been reported for ``old'' dentin. (C) 2016 Elsevier Ltd. All rights reserved.

Introduction: Although the strength and toughness of dentin decrease with age, no study has explored if restorative treatments are a contributing factor. Methods: Multiple extracted teeth were obtained from randomly selected donors and categorized according to donor age and prior root canal treatment. The microstructure and chemical composition of radicular dentin were evaluated using scanning electron microscopy and Raman spectroscopy, respectively, and the strength was evaluated in 4-point flexure to failure. Data were compared using the Student t test. Results: Dentin from the root canal–restored teeth exhibited significantly lower strength (P <.05) than tissue from age- and donor-matched unrestored tooth pairs. Although there was no significant difference in the mineral-to-collagen ratio between the 2 groups, dentin obtained from the root canal–treated teeth exhibited more extensive collagen cross-linking and lower tubule occlusion ratios than the unrestored tooth pairs. Conclusions: There is a decrease in the strength of radicular dentin with aging, but prior root canal treatment increases the extent of degradation. © 2018 American Association of Endodontists

A technique for implementing biocompatible and antibacterial functions to a targeted region on tooth surfaces has potential in dental treatments. We have recently demonstrated pseudo-biomineralization, i.e., the growth of an apatite layer on a human dentin substrate by a laser-assisted biomimetic (LAB) process, based on pulsed laser irradiation in a supersaturated CaP solution. In this study, pseudo-biomineralization was induced in the presence of fluoride ions using the LAB process in order to fabricate an antibacterial fluoride-incorporated apatite (FAp) layer on the dentin surface. After processing for 30 min, a micron-thick FAp layer was formed heterogeneously at the laser-irradiated solid-liquid interface via pseudo-biomineralization. A time-course study revealed that the LAB process first eliminated the pre-existing organic layer, while allowing fluoride incorporation into the dentin surface within 1 min. Within 5 min, FAp nanocrystals precipitated on the dentin surface. Within 30 min, these nanocrystals acquired a pillar-like structure that was weakly oriented in the direction normal to the substrate surface to form a dense micron-thick layer. This layer was integrated seamlessly with the underlying dentin without any apparent gaps. The FAp layer exhibited antibacterial activity against a major oral bacterium, Streptococcus mutans. The proposed LAB process is expected to be a useful new tool for tooth surface functionalization via facile and area-specific pseudo-biomineralization.

Purpose: The purpose of this study was to measure the shear bond strength (SBS) of glass ionomer cement (GIC) to artificial carious dentin with and without silver diamine fluoride (SDF) treatment. Methods: Permanent molars were sectioned and demineralized to create artificial carious lesions. In five groups, the demineralization of dentin, application of SDF, use of conditioner, and elapsed time between the placement of SDF and restoration were tested for differences in SBS using an UltraTester machine. Statistical analysis was done using the Kruskal-Wallis test and Tukey-Kramer multiple comparison tests. Results: The highest bond strength was found when GIC was placed on conditioned and demineralized dentin treated with SDF one week earlier. Treatment with SDF and use of conditioner did not statistically affect the SBS of GIC to demineralized dentin. Statistically significant increases in bond strength were found when one week elapsed between SDF application and GIC placement. The lowest bond strength was found with immediate GIC application onto SDF-treated demineralized dentin. Conclusions: These in vitro findings suggest that silver diamine fluoride treatment does not significantly affect the bond strength of glass ionomer cement to dentin lesions, and improved retention is obtained by allowing SDF solution to set for one week prior to GIC placement.

A technique for implementing biocompatible and antibacterial functions to a targeted region on tooth surfaces has potential in dental treatments. We have recently demonstrated pseudo-biomineralization, i.e., the growth of an apatite layer on a human dentin substrate by a laser-assisted biomimetic (LAB) process, based on pulsed laser irradiation in a supersaturated CaP solution. In this study, pseudo-biomineralization was induced in the presence of fluoride ions using the LAB process in order to fabricate an antibacterial fluoride-incorporated apatite (FAp) layer on the dentin surface. After processing for 30 min, a micron-thick FAp layer was formed heterogeneously at the laser-irradiated solid-liquid interface via pseudo-biomineralization. A time-course study revealed that the LAB process first eliminated the pre-existing organic layer, while allowing fluoride incorporation into the dentin surface within 1 min. Within 5 min, FAp nanocrystals precipitated on the dentin surface. Within 30 min, these nanocrystals acquired a pillar-like structure that was weakly oriented in the direction normal to the substrate surface to form a dense micron-thick layer. This layer was integrated seamlessly with the underlying dentin without any apparent gaps. The FAp layer exhibited antibacterial activity against a major oral bacterium, Streptococcus mutans. The proposed LAB process is expected to be a useful new tool for tooth surface functionalization via facile and area-specific pseudo-biomineralization.

A technique for implementing biocompatible and antibacterial functions to a targeted region on tooth surfaces has potential in dental treatments. We have recently demonstrated pseudo-biomineralization, i.e., the growth of an apatite layer on a human dentin substrate by a laser-assisted biomimetic (LAB) process, based on pulsed laser irradiation in a supersaturated CaP solution. In this study, pseudo-biomineralization was induced in the presence of fluoride ions using the LAB process in order to fabricate an antibacterial fluoride-incorporated apatite (FAp) layer on the dentin surface. After processing for 30 min, a micron-thick FAp layer was formed heterogeneously at the laser-irradiated solid-liquid interface via pseudo-biomineralization. A time-course study revealed that the LAB process first eliminated the pre-existing organic layer, while allowing fluoride incorporation into the dentin surface within 1 min. Within 5 min, FAp nanocrystals precipitated on the dentin surface. Within 30 min, these nanocrystals acquired a pillar-like structure that was weakly oriented in the direction normal to the substrate surface to form a dense micron-thick layer. This layer was integrated seamlessly with the underlying dentin without any apparent gaps. The FAp layer exhibited antibacterial activity against a major oral bacterium, Streptococcus mutans. The proposed LAB process is expected to be a useful new tool for tooth surface functionalization via facile and area-specific pseudo-biomineralization.

Purpose: This in vitro study aimed to evaluate the influence of dentin conditioning with polyacrylic acid on the shear bond strength of the nano-filled resin-modified glass ionomer cement Ketac N100 (3MESPE). Material and methods: Eighteen bovine incisors were randomly divided into two groups (n=18): group 1, without dentin surface treatment, and group 2, with dentin surface treated with 10% polyacrylic acid for 15 seconds. In both groups the primer was applied before the application of the nano-filled resin-modified glass ionomer cement (Ketac N100) and light-cured for 20 seconds. After 24 hours, the specimens were submitted to thermocycling for 350 cycles, and the teeth were immersed in distilled water at room temperature. After 24 hours, specimens were tested for shear bond strength at 1mm/minute crosshead speed. The collected data were analyzed using the non-parametric test of Mann Whitney (p<0.05). Results: There was a significant difference in shear bond strength values between the treatment and control groups, the group with dentin conditioning with 10% polyacrylic acid showed higher shear strength values than the group without dentin treatment. Conclusion: Application of 10% polyacrylic acid on dentin increases the shear bond strength values of nano-filled resin-modified glass ionomer cement., Objetivo: Este estudio in vitro tuvo como objetivo evaluar la influencia del acondicionamiento de la dentina con ácido poliacrílico sobre la resistencia al cizallamiento del cemento de ionómero de vidrio modificado con resina con tecnología de nano relleno Ketac N100 (3MESPE). Material y Métodos:Dieciocho incisivos bovinos se dividieron aleatoriamente en dos grupos (n = 18): el grupo 1, sin tratamiento de la superficie dentinaria, y el grupo 2, con la superficie dentinaria tratada con ácido poliacrílico al 10% durante 15 segundos. En ambos grupos, el Primer se aplicó antes de la aplicación del cemento de ionómero devidrio modificado con resina con tecnología de nano relleno (Ketac N100) y se fotopolimerizó durante 20 segundos. Después de 24 horas, las muestras se sometieron a 350 ciclos de termociclado y los dientes se sumergieron en agua destilada a temperatura ambiente.Después de 24 horas, las muestras se evaluaron para determinar la resistencia al cizallamiento a una velocidad constante de 1 mm / minuto. Los datos recolectados fueron analizados mediante la prueba no paramétrica de Mann Whitney (p<0.05). Resultados: Hubo una diferencia significativa en los valores de resistencia al cizallamiento entre los grupos de tratamiento y control, el grupo con acondicionamiento de dentina con ácido poliacrílico al 10% mostró valores de resistencia al cizallamiento más altos que el grupo sin tratamiento de la dentina. Conclusión: La aplicación de ácido poliacrílico al 10% sobre la dentina aumenta los valores de resistencia al cizallamiento del cemento de ionómero de vidrio modificado con resina con tecnología de nano relleno.

Objective: This study investigated the effect of endogenous erosion on the microhardness of dentine and a nanofilled composite resin. Procedures for preventing erosion were also studied. Materials and Methods:90 bovine dentine specimens were divided into three groups in accordance with the method for preventing: negative control, topical application of fluoride and resin-modified glass ionomer varnish. 120 composite resin specimens were distributed into four groups, which also included a resin sealant, among the preventive procedures. Specimens were then randomly divided into three sub-groups according to the exposure to simulate gastric acid solution and subsequent remineralization: negative control, 9 and 18 cycles. Surface analysis was carried out by measuring the Knoop hardness. The data obtained were statistically analyzed using 2-way ANOVA and Tukey test. Result: The mean hardness of dentine and of the composite specimens resin exhibited lower hardness after 18 cycles. However, the resin-modified glass ionomer varnish resulted in greater values compared to the other preventive procedures. Conclusion: A resin-modified glass ionomer varnish seems to be a promising method for minimizing the damage caused by endogenous acid, but its protection can be reduced depending on the intensity of the erosive challenge., Objetivo: Este estudio investigó el efecto de la erosión endógena sobre la microdureza de la dentina y una resina compuesta de nanorrelleno. También se estudiaron los procedimientos para prevenir la erosión. Materiales andMétodos: 90 muestras de dentina bovina se dividieron en tres grupos de acuerdo con el método para prevenir: control negativo, aplicación tópica de fluoruro y barniz de ionómero de vidrio modificado con resina. Se distribuyeron 120 muestras de resina compuesta en cuatro grupos, que también incluían un sellador de resina, entre los procedimientos preventivos. Las muestras se dividieron al azar en tres subgrupos de acuerdo con la exposición para simular la solución de ácido gástrico y la remineralización posterior: control negativo, 9 y 18 ciclos. El análisis de la superficie se realizó midiendo la dureza Knoop. Los datos obtenidos se analizaron estadísticamente mediante ANOVA de 2 vías y prueba de Tukey. Resultados: La dureza media de la dentina y de la resina de muestras compuestas exhibió una dureza más baja después de 18 ciclos. Sin embargo, el barniz de ionómero de vidrio modificado con resina resultó en valores mayores en comparación con los otros procedimientos preventivos.Conclusión: Un barniz de ionómero de vidrio modificado con resina parece ser un método prometedor para minimizar el daño causado por el ácido endógeno, pero su protección puede reducirse dependiendo de la intensidad del desafío erosivo.

Dentin, ili zubna kost, je čvrsto avaskulatno tkivo koje izgrađuje najveći deo zuba i daje mu oblik. Stvara se kontinuirano tokom života. Prožimaju ga dentinski kanalići u kojima se nalaze produžeci odontoblasta. Po biohemijskom sastavu, dentin se bitno razlikuje od gleđi, jer sadrži znatno veći procenat vode (10%) i organskih materija (20%). Preostali deo (70%) pripada neorganskim materijalima, prvenstveno Ca2+ i fosfatima u obliku kristala hidroksiapatita. Od organskih materija dentin najviše sadrži strukturni protein kolagen (18%) i nekolagene proteine, kao što su: dentinski fosfoprotein (DFP), dentinski sijaloprotein (DSP), dentinski matriksni protein (DMP). Nekolageni proteini su fosforilisani proteini čija je uloga u mineralizaciji dentina tokom procesa razvoja ovog zubnog tkiva (dentinogeneza). Sintetišu se od strane odontoblasta, kao i kolagen. Pored ova tri najzastupljenija proteina, u dentinu su prisutni i drugi makromolekuli (proteoglikani, drugi glikoproteini, serumski proteini, enzimi i faktori rasta) koji stupaju u složene interakcije i utiču na kvalitativne promene u ovom tkivu.

Dentin, ili zubna kost, je čvrsto avaskulatno tkivo koje izgrađuje najveći deo zuba i daje mu oblik. Stvara se kontinuirano tokom života. Prožimaju ga dentinski kanalići u kojima se nalaze produžeci odontoblasta. Po biohemijskom sastavu, dentin se bitno razlikuje od gleđi, jer sadrži znatno veći procenat vode (10%) i organskih materija (20%). Preostali deo (70%) pripada neorganskim materijalima, prvenstveno Ca2+ i fosfatima u obliku kristala hidroksiapatita. Od organskih materija dentin najviše sadrži strukturni protein kolagen (18%) i nekolagene proteine, kao što su: dentinski fosfoprotein (DFP), dentinski sijaloprotein (DSP), dentinski matriksni protein (DMP). Nekolageni proteini su fosforilisani proteini čija je uloga u mineralizaciji dentina tokom procesa razvoja ovog zubnog tkiva (dentinogeneza). Sintetišu se od strane odontoblasta, kao i kolagen. Pored ova tri najzastupljenija proteina, u dentinu su prisutni i drugi makromolekuli (proteoglikani, drugi glikoproteini, serumski proteini, enzimi i faktori rasta) koji stupaju u složene interakcije i utiču na kvalitativne promene u ovom tkivu.

Dentin hypersensitivity can be reduced by the use of a remineralization agent to hinder movement of fluids within the dentin tubules. Penetration of particles into the tubules and a continuous release of Ca2+ and phosphate ions can induce the mineralization of a material mimicking the mineral component of dentin, sealing the tubules. In this work, we have used complementary electron microscopy techniques to investigate the ultrastructure of dentin and crystallization and occlusion effects when using amorphous calcium magnesium phosphate (ACMP) microspheres on extracted human molars. Application of the particles in a gel intended for athome use resulted in intra-tubular mineralization of a carbonate substituted hydroxyapatite (HA). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that crystallization was initiated on the peritubular dentin (PTD) with undirected crystal growth leading to the formation of a porous material. We additionally investigated the effects from using a fluoride toothpaste to potentially improve the remineralization and anti-cariogenic properties of the ACMP microspheres. Energy dispersive x-ray spectroscopy (EDX) using TEM in scanning mode (STEM) showed that fluoride incorporation resulted in an increase in aspect ratio of the crystals, crystal growth directed towards the center of the tubule lumen and densification of the mineralized material. Thus, ACMP microspheres are promising alternatives as occluding agents and the efficacy of the particles could be further improved with the complementary use of a fluoride toothpaste.

Research of nonthermal atmospheric plasma (NTAP) for dental applications has been increasing in recent years. This paper presents a literature review of potential use of NTAP for treatment of surfaces of dental materials and hard dental tissues. The aim of NTAP interaction with dental materials and tissues is surface modification for stable and durable material-to-material or material-to-tissue bonds. Reactive particles in NTAP and various mixtures of gasses increase hydrophilicity of material surface, which is known to be hydrophobic in implants, ceramics or dental composites, with or without roughness changes. Adhesion of cells to implant surface was shown to improve after NTAP treatment, thereby promoting successful osseointegration. Bonding ceramic materials to the prepared surfaces of teeth or fiber/metal posts was shown to improve after NTAP treatment. Hard dental tissues achieve primarily micromechanical bonds with composite materials using dental adhesives. Increased organic content in the form of collagen fibrils and residual water pose a problem for achieving adequate and long-term adhesive-dentin bonds. This problem has not been solved with current adhesive application protocols. It was recently shown that application of NTAP improves the hydrophilicity of dentin surface and changes its polarity, which can contribute to better distribution of adhesive resin and deeper penetration into the hybrid layer. Previous studies pointed to similar or better initial adhesive bonds with dentin. However, adhesive-dentin bonds are subject to degradation in the long-term also after NTAP treatment suggesting the need for further optimization of NTAP for application on dentin.

This prospective cohort study investigated the distribution pattern of carious lesions diagnosed by visual tactile and radiographic examinations, assessed the radiographic yield for clinical caries diagnosis, and estimated how accurately commonly used indicators for caries identified young adults who would benefit from radiographs at different thresholds. Overall, 576 patients aged 16-32 years seeking a first consultation were included. Patients were examined for caries and answered a validated questionnaire on sociodemographics and oral health behavior. Almost 10% of clinically sound approximal surfaces presented radiolucency in enamel/dentine. Of the clinically diagnosed noncavitated approximal and occlusal lesions, 22.5 and 17.7%, respectively, presented radiolucency reaching dentine at the radiographic examination. Noncavitated/enamel lesions detected radiographically were mainly at approximal surfaces (73.2%), while at occlusal surfaces these were negligible (0.7%). More than half of approximal dentine lesions were only detected radiographically (61.3%), while more than half of occlusal dentine lesions were only clinically diagnosed (57.1%). The hierarchical logistic regression analysis showed that patient's caries activity, D1MFS scores ≥17, and frequent consumption of soft drinks were significantly associated with detection of approximal enamel/dentine lesions. Also, patient's caries activity and frequent consumption of soft drinks were significantly associated with occlusal dentine caries (p ≤ 0.05). The indicator power of grouping these indicators as a predictor for the presence of radiographically detected lesions showed high sensitivity (0.84-0.91) and moderate specificity (0.64-0.73) for all surfaces and thresholds tested. In conclusion, radiographs increased significantly the number of approximal enamel/dentine and occlusal dentine lesions diagnosed. The ability to identify young adults with approximal lesions from the predictor was satisfactory. Bearin

UNLABELLED: The addition of charged polymers, like poly-aspartic acid (pAsp), to mineralizing solutions allows for transport of calcium and phosphate ions into the lumen of collagen fibrils and subsequent crystallization of oriented apatite crystals by the so-called Polymer-Induced Liquid Precursor (PILP) mineralization process, leading to the functional recovery of artificial dentin lesions by intrafibrillar mineralization of collagen. OBJECTIVE: To evaluate the feasibility of applying the PILP method as part of a restorative treatment and test for effectiveness to functionally remineralize artificial lesions in dentin. MATERIALS AND METHODS: Two methods of providing pAsp to standardized artificial lesions during a restorative procedure were applied: (A) pAsp was mixed into commercial RMGI (resin modified glass ionomer) cement formulations and (B) pAsp was added at high concentration (25mg/ml) in solution to rehydrate lesions before restoring with a RMGI cement. All specimens were immersed in simulated body fluid for two weeks to allow for remineralization and then analyzed for dehydration shrinkage, integrity of cement-dentin interface, degree of mineralization, and changes in the nanomechanical profile (E-modulus) across the lesion. RESULTS: After the remineralization treatment, lesion shrinkage was significantly reduced for all treatment groups compared to demineralized samples. Pores developed in RMGI when pAsp was added. A thin layer at the dentin-cement interface, rich in polymer formed possibly from a reaction between pAsp and the RMGI. When analyzed by SEM under vacuum, most lesions delaminated from the cement interface. EDS-analysis showed some but not full recovery of calcium and phosphorous levels for treatment groups that involved pAsp. Nanoindentations placed across the interface indicated improvement for RMGI containing 40% pAsp, and were significantly elevated when lesions were rehydrated with pAsp before being restored with RMGI. In particular the m

OBJECTIVE: Improved methods are needed to remineralize dentin caries in order to promote conservation of dentin tissue and minimize the surgical interventions that are currently required for clinical treatment. Here, we test the hypothesis that bulk substrates can be effectively mineralized via a dual analog system proposed by others, using a tripolyphosphate (TPP) templating analog and a poly(acrylic acid) (PAA) or poly(aspartic acid) (pAsp) sequestration analog, the latter of which generates the polymer-induced liquid-precursor (PILP) mineralization process studied in our laboratory. MATERIAL & METHODS: Demineralized human dentin slices were remineralized with and without pre-treatment with TPP, using either PAA or pAsp as the PILP process-directing agent. A control experiment with no polymer present was used for comparison. RESULTS: No mineralization was observed in any of the PAA groups. In both the pAsp and no polymer groups, TPP inhibited mineralization on the surfaces of the specimens but promoted mineralization within the interiors. Pre-treatment with TPP enhanced overall mineralization of the pAsp group. However, when analysed via TEM, regions with little mineral were still present. CONCLUSION: Poly(acrylic acid) was unable to remineralize demineralized dentin slices under the conditions employed, even when pre-treated with TPP. However, pre-treatment with TPP enhanced overall mineralization of specimens that were PILP-remineralized using pAsp.