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The role of different toothpastes on preventing dentin erosion: An SEM and AFM study®
Abstract
The aim of the present in vitro study was the evaluation of new formulation toothpastes on preventing dentin erosion produced by a soft drink (Coca Cola®), using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Fifty dentin specimens were divided in treatment and control halves and were than assigned to 5 groups of 10 specimens each: group 1a: intact dentin, group 1b: dentin + soft drink, group 2a: intact dentin + Biorepair Plus-Sensitive Teeth®, group 2b: dentin + soft drink + Biorepair Plus-Sensitive Teeth®, group 3a: intact dentin + Biorepair Plus-Total Protection®, group 3b: dentin + soft drink + Biorepair Plus-Total Protection®, group 4a: intact dentin + Sensodyne Repair & Protect®, group 4b: dentin + soft drink + Sensodyne Repair & Protect®, group 5a: intact dentin + Colgate Sensitive Pro Relief®, group 5b: dentin + soft drink + Colgate Sensitive Pro Relief®. The surface of each specimen was imaged by AFM and SEM. Comparing specimens of group a and b (no demineralization and demineralization), a statistically significant difference (p < 0.01) in Rrms values was registered. Comparing b groups, all the analyzed toothpastes tended to remineralize the dentine surface in different extent. Biorepair Plus-Total Protection® and Sensodyne Repair & Protect® provided higher protective effect against dentin demineralization. SCANNING 9999:XX-XX, 2013. © 2013 Wiley Periodicals, Inc.
... Thus, preventive measures against erosion are required. [4] Enamel has no spontaneous capability to repair when affected by specific dental pathologies such as caries, abrasions or fractures because it contains no cells. [5] Therefore, when enamel is exposed to oral environment, the only possibility to be reconstructed depends on the application of alloplastic materials, which provide a sort of prosthetic restoration. ...
... [5] Therefore, when enamel is exposed to oral environment, the only possibility to be reconstructed depends on the application of alloplastic materials, which provide a sort of prosthetic restoration. [4] With improved oral hygiene and fluoridated pastes being commonly used, there has been a decline in incidence of tooth demineralisation, resulting in increased fluoride content in saliva. [6] Various fluoridated formulations have been tested but the major shortcoming of these is that their ability to remineralise enamel is limited by the low concentration of calcium and phosphate ions available in saliva. ...
Background:
Erosion, a dynamic process with periods of demineralisation and remineralisation, has become a common problem in modern societies, owing to changes in life style and dietary habits. Although fluorides have been included in toothpastes that claim to prevent demineralisation and aid remineralisation, their ability to remineralise is limited by low concentration of calcium and phosphate ions available in saliva. Hence, a new paste based on casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), nanohydroxyapatite and bioactive glass (BAG) were introduced.
Aim:
To evaluate and compare the effects of BAG, nanohydroxyapatite and CPP-ACPF pastes on surface microhardness of demineralised enamel.
Materials and methods:
48 enamel specimens were randomly divided into five groups: Group I positive control - intact specimens and Group II - demineralised specimens. The test groups, Group III, IV and V, comprised CPP-ACPF, nanohydroxyapatite and BAG, respectively. The test specimens were demineralised with 0.1% citric acid followed by remineralisation using either of the three prepared slurries. The specimens were subjected to pH cycling regime for 15 times. The remineralisation potential of the specimens was studied by evaluating the surface microhardness. One specimen from each group was analysed under SEM. Data was tabulated and analysis performed by one way ANOVA and post hoc Scheffe test.
Results:
Statistically significant difference was found between the negative control and three test groups based on microhardness evaluation. Nanohydroxyapatite had the least remineralising potential as compared to CPP-ACPF and BAG.
Conclusion:
Comparatively, BAG and CCP-ACPF paste showed better remineralising potential.
... Para la observación morfológica se utilizó SEM a 1000× (Elkassas & Arafa, 2014;Poggio et al., 2014;Oliveira et al., 2016). Un bloque de muestras por cada grupo se montó rígidamente en dos portaobjetos de vidrio con la ayuda de cinta adhesiva de carbono. ...
... Esto último para evitar sesgos de observación. Para la evaluación de imágenes SEM, se escogió el acondicionamiento previo con oro conforme a otros estudios ( Poggio et al., 2014Poggio et al., , 2016Brar et al., 2017;Jena et al., 2017). Al no poder realizar medidas repetidas, se trató de estandarizar las muestras, primero, aleatorizando los dientes en los grupos de pastas dentales (15 dientes por grupo). ...
RESUMEN
Antecedentes: Las lesiones de manchas blancas (WSL) representan el primer signo de caries dental. El flúor es comúnmente usado para su tratamiento, sin embargo, se ha introducido tecnología de nanopartículas que usan calcio, fósforo y flúor como: Remin Pro, hidroxiapatita fluorada (HA-F); Mi Paste Plus, fosfopéptido de caseína fosfato de calcio amorfo fluorado (CPP-ACPF); Clinpro Tooth Crème, fosfato tricálcico fluorado (f-TCP) y Sensodyne Repair and Protect, fosfosilicato de calcio y sodio fluorado (CSPS-F). Se cree que esta combinación de minerales es capaz de detener lesiones activas por medio de la acción compleja de sus iones.
Objetivo: El objetivo de esta serie de trabajos fue evaluar la efectividad de cuatro pastas dentales a base de calcio, fosfato y flúor en la remineralización de lesiones iniciales de caries observadas en la microdureza y morfología (Estudio 1), el perfil mineral y ultraestructural (Estudio 2), la regresión y descalcificación (Estudio 3).
Material y Métodos: Estudio 1. 104 especímenes de esmalte, colocados en bloques acrílicos y sometidos a un ciclo de pH se distribuyeron en seis grupos: HA-F, CPP-ACPF, f-TCP, CSPS-F, Controles positivo y negativo. Las pastas se aplicaron en tres tiempos de forma tópica y con cepillado eléctrico. Se midió la microdureza de Vickers (VHN), la reconversión de VHN (SMHR), el cambio de VHN (SMHC) y la morfología de superficies usando microscopía de electrónica de barrido (SEM) a 1000×, observados al inicio, postdesmineralización, 15 y 30 días postratamiento. Estudio 2. Lesiones de caries artificiales se crearon en 240 especímenes. Se distribuyeron en cuatro grupos: HA-F, CPP-ACPF, f-TCP y CSPS-F. Las pastas se aplicaron en tres tiempos de forma tópica y con cepillado eléctrico. Se midió el peso y la ganancia mineral de calcio, fósforo y flúor, y la ultramorfología usando SEM con espectroscopia de energía dispersiva (EDS) a 5000×, vistos al inicio, postdesmineralización, 15 y 30 días postratamiento. Estudio 3. Ensayo clínico controlado realizado en 52 niños de 6 y 7 años con al menos una WSL. Se distribuyeron en cinco grupos: HA-F, CPP-ACPF, f-TCP, CSPS-F y control con pasta fluorada. Se aplicó dos usos diarios durante 3 semanas con cepillado manual-eléctrico y tópica en cubetas. Se midió las áreas, la regresión y la descalcificación de WSL.
Resultados: Estudio 1. Todos los dentífricos aumentaron significativamente el VHN después de 30 días postratamiento. HA-F y CSPS-F también fueron significativamente efectivos a los 15 días. Se observó un valor significativamente mayor de SMHR y SMHC con HA-F, f-TCP y CSPS-F en la primera remineralización y CPP-ACPF en la segunda remineralización en comparación con los grupos controles. Imágenes SEM revelaron que todos los grupos fueron capaces de reparar la morfología de las superficies. Estudio 2. Todos los dentífricos recuperaron significativamente el contenido mineral después de 15 días de aplicación, con excepción de HA-F que recuperó el contenido de calcio a los 30 días. La ganancia mineral fue positiva y no se mostró diferente entre grupos. Imágenes SEM revelaron que todos los grupos fueron capaces de reducir la permeabilidad formando un revestimiento mineral. Estudio 3. El tratamiento de los grupos experimentales mostraron una disminución significativa de WSL, valores más altos de RW y una disminución de la severidad del ID, en comparación con el grupo control. La disminución ID se asoció significativamente a HA-F, CPP-ACPF y f-TCP a diferencia del grupo de control. Aunque CSPS-F fue más efectivo que el grupo control en disminuir el ID, no fue estadísticamente diferente.
Conclusiones: Tras el análisis de los tres estudios, puede concluirse que las pastas dentales basadas en calcio-fosfato-flúor se presentan efectivos para el tratamiento de lesiones iniciales de caries.
PALABRAS CLAVE: CPP-ACP, fosfato tricálcico, fosfosilicato de calcio y sodio, hidroxiapatita, lesiones de mancha blanca, microdureza, SEM, remineralización.
... Brushed groups ( Figure 2) were almost totally covered with a layer of deposits completely occluding dentinal tubules, except in the PC group ( Figure 2). Our topical group observations agree with previous SEM findings by Poggio et al. [39]. ...
Objective: The purpose of this in vitro study was to evaluate the potential remineralization of enamel and dentine erosion lesions after the application of five different toothpastes.
Methodology: A total of 104 enamel and dentine samples were prepared from maxillary third molars. Each group was divided according to the toothpaste application mode (topical = 56; brushing = 48) and the toothpaste used seven topical groups and six brushing groups (n = 8). The groups included negative control (NC), positive control (PC), Sensodyne Pronamel (SP), Regenerate (R), Regenerate with boosting serum (R+), Colgate Duraphat 5000 (CD), and tooth mousse (TM).
Results: The statistical analysis showed significant surface microhardness (SMH) change. All enamel groups showed a significant decrease in SMH compared to NC for both application modes. However, no significance was recorded between test groups. Similar results were observed between dentine groups and their relevant controls for both application modes, except brushed R and R+ groups, which were insignificant to their NC. For topical groups, TM showed a significant increase in SMH. While R and R+ showed lower loss than SP and CD.
Conclusions: All tested agents offered a degree of remineralization in both enamel and dentine with no significant difference between agents in enamel groups while R, R+, and TM offered better results in dentine groups.
Clinical significance: For dentine groups, similar findings were observed with superior tooth surface protection with the application of TM over other agents. Tooth surface remineralization was achieved when agents were either applied topically or brushed over the surface.
... In recent years, synthetic hydroxyapatite, and more specifically nanohydroxyapatite (nanoHAP), has been proposed as a better alternative due to its high biocompatibility, bioactivity, and similarity to the one already present in enamel. Thus, the effectiveness of HAP regarding remineralization has led to multiple studies discussing its presence in different oral-care products [20][21][22][23][24][25][26][27][28][29][30][31][32]. ...
To address tooth enamel demineralization resulting from factors such as acid erosion, abrasion, and chronic illness treatments, it is important to develop effective daily dental care products promoting enamel preservation and surface remineralization. This study focused on formulating four toothpastes, each containing calcined synthetic hydroxyapatite (HAP) in distinct compositions, each at 4%, along with 1.3% birch extract. Substitution elements were introduced within the HAP structure to enhance enamel remineralization. The efficacy of each toothpaste formulation was evaluated for repairing enamel and for establishing the dynamic of the remineralization. This was performed by using an in vitro assessment of artificially demineralized enamel slices. The structural HAP features explored by XRD and enamel surface quality by AFM revealed notable restorative properties of these toothpastes. Topographic images and the self-assembly of HAP nanoparticles into thin films on enamel surfaces showcased the formulations’ effectiveness. Surface roughness was evaluated through statistical analysis using one-way ANOVA followed by post-test Bonferroni’s multiple comparison test with a p value < 0.05 significance setting. Remarkably, enamel nanostructure normalization was observed within a short 10-day period of toothpaste treatment. Optimal remineralization for all toothpastes was reached after about 30 days of treatment. These toothpastes containing birch extract also have a dual function of mineralizing enamel while simultaneously promoting enamel health and restoration.
... In a clinical study, Gopinath et al. also demonstrated that n-HAP toothpaste had the same efficiency in DH reduction as toothpaste based on NovaMin ® technology [34]. The results of our study are also in agreement with the study of Poggio et al., which evaluated the capacity of desensitizing toothpastes to prevent dental erosion caused by an acidic beverage and demonstrated that Biorepair Plus-Total Protection (active ingredient Zn substituted n-HAP-MicroRepair ® technology) and Sensodyne Repair and Protect (NovaMin ® technology) presented high potential for dentinal tubule occlusion [35]. The same study demonstrated the remineralization capacity of both products, with the minerals being integrated into the collagen network after acidic attack. ...
There are two main methods used for dentin hypersensitivity (DH) treatment: dentinal tubule occlusion and blockage of nerve activity. Dentifrices are the most common vehicles for active ingredients used for DH treatment. The aim of this study was to evaluate the efficacy of three toothpastes on dentinal tubule occlusion, mineral acquisition, and dentin hardness. Forty human dentin disks were submerged in 40% citric acid for 30 s and then exposed to tooth brushing for 2 min twice a day for 14 days using three toothpastes: Dontodent Sensitive (group 1), Dr. Wolff’s Biorepair (group 2), and Sensodyne Repair and Protect (group 3). In the control group (group 4), the samples were brushed with water. All of the samples were evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Vickers dentin hardness determination. On SEM images, the degree of dentinal tubule occlusion was assessed using a five-grade scale. The mean score values in groups 1–4 were 3.60 ± 0.69, 2.20 ± 0.91, 2.30 ± 1.16, and 5.00 ± 0.00, significantly higher in study groups when compared to the control group (Kruskal Wallis test p < 0.05). EDX evaluation showed significantly higher calcium and phosphorus concentrations in groups 1 and 3 when compared to control group d. The mean values of Vickers dentin hardness numbers in groups 1–4 were 243.03 ± 10.014, 327.38 ± 56.65, 260.29 ± 37.69, and 225.83 ± 29.93, respectively. No statistically significant results were obtained when comparing the hardness mean values in groups (Kruskal-Wallis statistical test, p = 0.372 > 0.05). All three toothpastes tested demonstrated significant occlusion of dentinal tubules. Dontodent Sensitive and Sensodyne Repair and Protect toothpastes enhanced the calcium and phosphorus content of the dentin surface. None of the toothpastes increased dentin hardness as a result of mineral acquisition.
... A report by Poggio et al. [35] provides a clear insight into this question. It also compared the efficacy of different toothpaste technologies for the management of dentin erosion. ...
Biomimetic zinc–carbonate hydroxyapatite technology was developed to realize materials that mimic the natural hydroxyapatite of enamel and dentin and possess good activity in terms of affinity to adhere to these biological tissues. The chemical and physical characteristics of this active ingredient allows the hydroxyapatite itself to be particularly similar to dental hydroxyapatite, enhancing the bond between biomimetic hydroxyapatite and dental hydroxyapatite. The aim of this review is to assess the efficacy of this technology in terms of benefits for enamel and dentin and reduction of dental hypersensitivity. Materials and methods: A literature search (Pubmed/MEDLINE and Scopus) of articles from 2003 to 2023 was conducted to analyze studies focused on the use of zinc-hydroxyapatite products. Duplicates were eliminated from the 5065 articles found, leaving 2076 articles. Of these, 30 articles were analyzed based on the use of products with zinc–carbonate hydroxyapatite in these studies. Results: 30 articles were included. Most of the studies showed benefits in terms of remineralization and prevention of enamel demineralization in terms of occlusion of the dentinal tubules and reduction of dentinal hypersensitivity. Conclusion: Oral care products such as toothpaste and mouthwash with biomimetic zinc–carbonate hydroxyapatite were shown to provide benefits according to the aims of this review.
... More recently, scanning and transmission electron microscopy and then atomic force microscopy (scanning probe microscopy) were introduced in the study of dental tissue textures (9) . Laser confocal microscopy was an outstanding technique for observation of the threedimensional texture of dental tissues (10) . ...
Fine histological structures of human tooth were examined through diffraction-enhanced imaging using highly spatial coherent parametric X-ray (PXR) generated by a small-scale electron accelerator at the Laboratory for Electron Beam Research and Application (LEBRA), Nihon University. LEBRA-PXR is used as an electron linear accelerator (LINAC) based joint-use X-ray source to facilitate advanced X-ray imaging experiments such as phase-contrast imaging with diffraction-enhanced imaging (DEI),
which has been considered difficult to perform outside a synchrotron radiation facility.
In this study, several microscopic-order structures of the enamel and dentin were identified through ultra-small–angle X-ray scattering（USAXS）imaging using DEI, although these structures were not visualized through the refraction-angle image of DEI except for the contour lines of the tooth and enamel–dentin junction. In USAXS images, local variations in dentin structures, particularly in the presence of micro-sized tubules, such as dentin tubules, were visualized differently depending on the sample orientation. The
specimen’s appearance when the tooth axis was parallel to the floor differed from that when it was vertical to the floor. Such directional dependence is unique to LEBRA-PXR, which is sensitive to horizontal but not vertical refraction and scattering. The orientation of anisotropic sample structures was confirmed by changing the sample orientation. PXR generated in a small LINAC system was sufficient to observe tooth histological structures. Technical improvements should lead to clearer and more detailed images of inner-teeth structures, and the possibility of three-dimensional construction using phase contrast imaging would help in the detailed elucidation of tooth development, growth, and calcification mechanism.
... Also, we evaluated two types of active compounds contained in a dentifrice. These two brands of dentifrices were selected because they are available for sale in pharmacies and supermarkets and because they bring active compounds recently presented as effective in dental protection (Crastechini et al., 2019;João-Souza et al., 2019;Lombardini et al., 2014;Olley et al., 2012;Poggio et al., 2014;Sanchez et al., 2018;Sullivan et al., 2014;Sun et al., 2014;Wood et al., 2018). ...
This study aimed to evaluate the tooth after brushing with toothpaste containing or not active compounds and with different fluoride concentrations after erosion to establish and compare the effectiveness of each dentifrice in its use. Enamel, E (n=36) and dentin, D (n=36) bovine specimens were treated with artificial saliva (AS - control), fluoridated dentifrice (FD), 8% arginine (AR), and calcium silicate (CS). The samples (n=72) were subjected to cycles of demineralization (orange juice) followed by remineralization (saliva) and then tooth brushing (AR, FD and CS). The above cycle was repeated 3´/day for five days. Micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF), roughness testing and scanning electron microscopy (SEM) were performed. The mean of roughness values (Ra, μm) were E-AS, 0.20; E-FD, 0.15; E-AR, 0.18; E-CS, 0.18; D-AS, 0.31; D-FD, 0.30; D-AR, 0.37; D-CS, 0.44. The SEM images showed a clear loss of tooth substance in AS and FD treatments. A significant positive mineral variation was observed on the dentin after brushed with AR (p<0.05). The FD dentifrice minimized the erosive effects of the orange juice. Arginine and calcium silicate could improve dental protection by the deposition of a surface layer of deposits. Different active compounds resulted in diverse degrees of protection regarding the type of substrate. The high concentration of fluoride and the inclusion of active compounds improves the dentifrice protection level.
... In our study none of the three n-HAp toothpastes determined complete occlusion of the dentinal tubules. Previous studies also showed partial closure of the dentinal tubules after an acid attack when using Biorepair Plus Sensitive toothpaste [32]. A study that tested n-HAp toothpaste Renamel (Sangi, Tokyo, Japan) had also demonstrated partial occlusion of dentinal tubules. ...
This in vitro study evaluated the effects of dentifrices containing nano-hydroxyapatite (n-HAp) on dentinal tubule occlusion and on mineral deposition. Dentin specimens of ten human teeth were submersed for 30 s in 40% citric acid and then randomly divided into four groups (three study groups and one control group). In the study groups, the dentin samples were exposed to three different n-HAp toothpastes: Karex (Dr. Kurt Wolff GmbH & Co. KG, Bielefeld, Germany), Biorepair Plus Sensitive (Coswell SpA, Bologna, Italy), and Dr. Wolff’s Biorepair (Dr. Kurt Wolff GmbH & Co. KG, Bielefeld, Germany); in the control group no toothpaste was applied. All of the samples were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. In the control group all of the samples showed a frank and wide opening of the dentinal tubules, whereas in the study groups different degrees of tubule closure by mineral depositions were observed. Toothpastes containing n-HAp determined a significant occlusion of dentinal tubules and a significant increase of mineral deposition on the dentin surface. All three tested toothpastes showed similar results regarding the degree of dentinal tubule closure. Varying degrees of differences in calcium, phosphate, carbon, and oxygen ion concentrations among the three tested toothpastes were obtained.
... Although most of the literature confirmed these promising properties of hydroxyapatite nanoparticles, there are very divergent results [7]. While an increasing number of experiments revealed the potential of nano-HAP to repair enamel [1,2,[19][20][21], other studies present no difference between the nano-HAP treatment and the standard fluoride treatment regarding the remineralization effects, some even showing less effective results [3,11,22]. These varying conclusions might be related to the methodology applied. ...
Hydroxyapatite nanoparticles (nano-HAP) are receiving considerable attention for dental applications, and their adhesion to enamel is well established. However, there are no reports concerning the effects of HAP on other dental materials, and most of the studies in this field are based on in vitro designs, neglecting the salivary pellicle-apatite interactions. Thus, this in situ pilot study aims to evaluate the effects of three hydroxyapatite-based solutions and their interactions with different dental material surfaces under oral conditions. Hence, two volunteers carried intraoral splints with mounted samples from enamel and from three dental materials: titanium, ceramics, and polymethyl-methacrylate (PMMA). Three HAP watery solutions (5%) were prepared with different shapes and sizes of nano-HAP (HAP I, HAP II, HAP III). After 3 min of pellicle formation, 10 ml rinse was performed during 30 sec. Rinsing with water served as control. Samples were accessed immediately after rinsing, 30 min and 2 h after rinsing. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the particles, and SEM evaluated the pellicle-HAP interactions. SEM and TEM results showed a high variation in the size range of the particles applied. A heterogeneous HAP layer was present after 2 h on enamel, titanium, ceramics, and PMMA surfaces under oral conditions. Bridge-like structures were visible between the nano-HAP and the pellicle formed on enamel, titanium, and PMMA surfaces. In conclusion, nano-HAP can adhere not only to enamel but also to artificial dental surfaces under oral conditions. The experiment showed that the acquired pellicle act as a bridge between the nano-HAP and the materials’ surface.
... Modern biomimetic nanoparticles prevent mineral loss and remineralize enamel lesions (Hannig and Hannig 2010;Tschoppe et al. 2011). Enamel remineralizing substances like HAp NPs and Zn-carbonate hydroxyapatite induce precipitation of mineral on eroded dentine and enamel (Poggio et al. 2014). The addition of HAp micro clusters to soft drink, mouthwashes and toothpaste can promote coating of a carbonate-hydroxyapatite particle on eroded enamel and decreases erosiveness of enamel because of the super saturation of calcium and phosphate (Poggio et al. 2010;Roveri et al. 2008;Min et al. 2015). ...
Nanotechnology offers promising tools in interdisciplinary research areas that include information technology, optics, electronics, magnetics, materials development, and biomedicine. Being measured on molecular scale, it is getting an upsurge of interest in cancer therapeutics. In the past couple of decades, nanotechnology has been emerged out as an extraordinary platform to provide treatment of cancer at an early stage without affecting the neighboring healthy cells and hence attracts scientists to put an effort toward the complete eradication of cancer in the coming years. The use of nanotechnology in different cancer therapies such as chemotherapy, gene therapy, radiation therapy, and radiofrequency therapy has revolutionized oncology. Recent advancements in diverse nano-devices including lipid, polymer, carbon, and inorganic-based nanostructures have been highlighted in the present chapter to treat cancer by different approaches. Nanomaterials offer diverse effect on treatment processes and well-designed specific and selective vectors have been gaining much attention in last few years. However, the fate of nanomaterials administered in vivo must be accounted for to ensure their safe use.
... 16 More recently, topographical and numerical analysis of dentine surface was performed by AFM to evaluate the efficacy of a new formulation toothpaste for the prevention of dentine erosion. 17 It appears that AFM is highly suitable for the assessment of early dentine erosion because of its ability to qualify and quantify erosion at an atomic level in real time on native surfaces. However, the time needed in scanning and its ability to scan only a small area might limit its usefulness for longitudinal studies. ...
Dentine erosion is an increasingly recognised problem, especially in aging population, and various methods have been utilised for its assessment. This narrative review was planned to summarise the methods for the assessment of the early stages of dentine erosion. Relevant original articles published in the English language from 2013 to 2017 were reviewed. Laboratory techniques and methods with in vivo potential were separately studied. It is evident that the assessment of early dentine erosion is complex and requires a combination of methods. For clinical evaluation, chemical analysis and optical methods show great potential but are in need of more validation.
... Worldwide and extensive use of cola beverages and their well-proven adverse effects on teeth and dental appliances, made the researchers to use them as a semi-standardized, safe and inexpensive medium for dentistry studies. In this context, cola beverages are used mainly as a control for comparison of staining [59,62], erosive [63][64][65][66] or abrasive [67] effects of other foods or drinks especially on enamel [68,69] or dentin [70,71]. Another major use is evaluation of roughness [72], hardness [73], surface topography [74], acid resistance [75], pH alterations [76], color stability [77] and bond strength [78] characteristics of dental wares or materials like orthodontic elastomeric modules, composite resins, restorative materials, orthodontic brackets, intraoral prostheses and inter-maxillary elastics. ...
Background
Excessive consumption of cola beverages is accompanied by numerous public health risks. But besides these well-known adverse effects, recently, several medical articles have been published that show some indications for cola beverages in clinical practice like resolution of gastrointestinal or feeding tube obstructions, increasing bioavailability and palatability of other medications, rehydration and other uses in healthcare settings. These approaches are not without shortcomings and complications.
Methods
In this systematic review we tried to explore these new uses for practitioners and also reemphasize on the most evidence-based complications of cola consumption like bone loss and metabolic and cardiovascular adverse effects in cases of misuse and overuse from both clinical and nutritional points of view via searching the PubMed database.
Results
We chose 145 journal articles from the most relevant ones plus 30 extra references and categorized their topics in two classes of medical uses and adverse effects.
Conclusion
It could be stated that cola beverages have demonstrated interesting uses and benefits in medicine but their use should be regulated as strict as possible.
... G1 showed the highest value of surface roughness and volume loss in the treated area followed by erosion, demonstrating that the absence of any kind of preventive treatment enhances the action of Coca Cola®, that is, demineralization on the surface of the root dentin. In fact, analysis of atomic force microscopy and scanning electron microscopy have also reported changes in the dentin surface provoked by erosion in this soft-drink [27]. ...
This in vitro study evaluated the influence of the Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin. Eighty dentin specimens were selected and divided into eight groups (n = 10): G1: negative control; G2: positive control (5% fluoride varnish-FV); G3: Er,Cr:YSGG laser; G4: FV + laser; G5: 3% potassium oxalate; G6: 3% potassium oxalate + laser; G7: biphasic calcium silicate/phosphate gel (gel); G8: gel + laser. Laser parameters: 0.5 W, 6.25 J/cm² at 1-mm distance. The erosive drink used was a cola soft-drink (pH = 2.42 at 4 °C), lasting 5 min, twice a day, with 6-h intervals between the challenges, during 14 days. Kolmogorov-Smirnov and Levene’s tests were satisfied. The surface roughness data were submitted to ANOVA and Tukey post hoc tests. For the wear profile, Kruskal-Wallis and Dunn post hoc tests were used. Afterwards, the Spearman correlation test was performed. All statistical tests assumed a significance level of 5% (α = 0.05). G1 presented the highest surface roughness value after the erosive challenge (3.586 μm² ± 0.205 μm²) and the G7 presented the lowest surface roughness value after the erosive challenge (1.071 μm² ± 0.180 μm²). For the lost volume, G4 presented the lowest percentage (9.7% ± 0.9%), while G1 had the highest percentage (41.8% ± 2.5%), both with p < 0.05. There was a weak correlation between the response variables (ρ = 0.33). All groups presented lower values of surface roughness and loss of volume when compared to the negative control group. For the surface roughness, the biphasic calcium silicate/phosphate gel presented the best result. For volume loss, the 5% fluoride varnish + Er,Cr:YSGG laser showed the best results compared to the other groups.
... Each tooth-half was fixed with superglue on the custom made acrylic block so that the buccal side of each was available, and assigned a serial number from 1 to 40. The labial surfaces were polished sub-sequentially starting from 600grit abrasive paper discs up to 1200 grit under water irrigation to produce flat enamel surfaces (16)(17)(18)(19) . Enamel samples were divided equally into two groups according to the material used (A 1 ), (A 2 ) and further subdivided into four subgroups according to the number of applications (A 1 B 1 ), (A 1 B 2 ), (A 2 B 1 ) and (A 2 B 2 ). ...
... Microscopic analysis showed that ivory tubules were of comparable size and shape to those in human dentine but of lower density. Sizes observed were comparable with those observed previously with human dentine [17][18][19]. Tubule density increasing in human dentine closer to the pulp has been previously reported [20]. ...
This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa) was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable “self–bonding” composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively.
... SDS is used in several PCPs, most notably in hair coloring products, which rank fourth in ENM use in PCPs at Fig. 2 Comparison of amount applied per capita (g yr -1 ) between previous studies (Loretz et al. 2005(Loretz et al. , 2006(Loretz et al. , 2008 and the current US survey. Error bars represent tenth and ninetieth percentiles (Tschoppe et al. 2011;Poggio et al. 2013). Carbon black (0.4 % of ENM mass flows in PCPs) is used mostly in nail polish and eye makeup. ...
Abstract The impetus for this study was to provide release estimates that can serve to improve predictions of engineered nanomaterial (ENM) exposure for risk assessment. We determined the likely release of ENMs from personal care products (PCPs) through a consumer survey on use and disposal habits, and research on the types and quantities of ENMs in PCPs. Our estimates show that in the US zinc oxide (ZnO), with 1,800–2,100 mt yr−1, and titanium dioxide (TiO2), with 870–1,000 mt yr−1, represent 94 % of ENMs released into the environment or landfills from the use of PCPs. Around 36–43 % of ENMs from PCPs were estimated to end up in landfills, 24–36 % released to soils, 0.7–0.8 % to air, and 28–32 % to water bodies. ENMs in sunscreen represent around 81–82 % of total release, from ZnO and TiO2 as UV blockers, followed by facial moisturizer (7.5 %), foundation (5.7 %), and hair coloring products (3.1 %). Daily care products such as body wash, shampoo, and conditioner had by far the highest per capita and total use, but contributed little to the ENM release estimates as these products generally contain little or no ENMs. However, if ENMs are incorporated into these daily care products, this may substantially increase ENM release. Graphical Abstract
Objective:
In this study, dentine surface was analysed through Environmental-scanning-electron-microscopy (ESEM) with energy-dispersive-X-ray-spectrometry (EDX) and Fourier-transform-infrared-spectroscopy (FTIR) with attenuated total-reflectance (ATR) to assess the morpho-chemical changes and variations in mineralization degree after demineralizing treatment, after five toothpastes application (HA & Citrate toothpaste, Zinc-HA toothpaste, Calcium Sodium Phosphosilicate toothpaste, Arginine & Calcium carbonate toothpaste, Colgate-Triple-Action, and Control toothpaste), after soaking in artificial saliva and after citric acid attack.
Methods:
Ca/P, Ca/N and P/N ratios were calculated from EDX atomic data to evaluate the mineralization degree of dentine surface. The IR calcium phosphate (CaP)/collagen and carbonate/collagen ratios has been evaluated to assess the remineralization changes in dentine; the carbonate/collagen IR ratio was calculated to identify the nucleation of B-type-carbonated apatite and calcium carbonate.
Results:
ESEM-EDX and ATR-FTIR showed residuals of toothpastes after the treatments in all cases, with a general increase in the mineralization degree after soaking in artificial saliva and a decrease after acid attack. Treatment with Arginine & Calcium carbonate toothpaste showed the highest Ca/P value after treatment (Ca/P 1.62) and acid attack (Ca/P 1.5) in confirmation, IR showed the highest amount of carbonate after treatment and soaking in artificial saliva. Arginine and calcium carbonate toothpaste and HA and citrate toothpaste remained to a higher extent on the dentine surface and revealed a higher remineralization activity. These formulations showed higher resistance to demineralization attack, as demonstrated by a higher ICaP /IAmide II intensity ratio than those obtained after EDTA treatment.
Conclusions:
Toothpastes that remained to a higher extent on dentine surface (arginine and calcium carbonate toothpaste in particular) were more able to promote remineralization. The formed calcium phosphate (CaPs) phase was intimately bound to dentine rather than a simple deposit.
Critical-sized defects in bone induced by trauma have in numerous presented cases difficult challenges to the current treatment for bone repair. The main purpose of bone tissue engineered scaffolds is to use advanced materials to promote the natural healing process of bone which does not easily occur in critical-sized defects or on metallic implants. A synthetic bone scaffold and a coating on Ti implants must be biocompatible and biodegradable to allow the native tissue integration, and mimic the chemical composition and structure of native bone. In addition to being physically and chemically biomimetic, an ideal scaffold and the coating layers on metallic implants must be capable of releasing essential physiologic elements, like Mg, Zn, Sr and Si, and also containing bioactive molecules (e.g., collagen, COL) to accelerate extracellular matrix production and tissue integration. Also, these advanced materials might be doped with drugs (e.g., antibiotics, such as vancomycin) to prevent undesired biological response such as infections, especially with Staphylococcus aureus, S. aureus. Various biomaterials include hydroxyapatite (HAP) ceramics or multifunctional hydroxyapatite substituted with Mg, Zn, Sr and Si, mf-HAP, polymers, such as poly lactic acid (PLA, approved for medical applications by Food and Drug Administration, US FDA, and collagen, or their mixtures as biomimetic composites which have been investigated for their potential as bone scaffold materials and coatings on metallic implants. This article briefly reviews the physical and chemical characteristics of used advanced materials and describes the key-technologies in mimicking the physical and chemical environment of bone using synthetic materials, and provides an over view of local drug delivery as it pertains to bone tissue engineering.
Objectives:
The aim of this study was to evaluate the efficiency of xylitol chewing gums enriched with propolis, remineralizing softly demineralized dentin in vitro.
Design:
Four groups of chewing gum were developed; Group1: xylitol (1.8 %), Group2: xylitol + casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (3%), Group3: xylitol+Hydroxyapatite (3%) and Group4: xylitol + propolis (5%). A control group was designed without chewing gum, but with artificial saliva. Sections of embedded crowns and cleaned roots of twenty five bovine incisors were demineralized in carbonated drink. Crown specimens were half-varnished. Remineralization process was run for all the dental specimens in the 4 groups with gum extracts and in the control group with artificial saliva for 20 min at 37 °C three times a day during 7 days. Mineral contents were evaluated by scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX-SEM). Surface morphology and roughness were analyzed using atomic force microscopy (AFM). Micro-hardness was measured using Vickers micro-hardness tester among varnished and unvarnished sides.
Results:
Calcium/Phosphate mean ratio showed a significant decrease between the control group, group1, group2 and group4. Control group and group3 were not significantly different. Micro-hardness increased significantly for all treated groups. AFM showed obstruction of dentinal tubules in all the groups and roughness decreased in the treated side of the dentin compared to the untreated side for tested groups.
Conclusion:
Xylitol chewing gum enriched with propolis showed dentinal tubules occlusion, significant improvement of micro-hardness and slight decrease in roughness. Ca/P ratio analysis suggests that a mineral compound other than hydroxyapatite is responsible of tubules occlusion.
The tooth is an important part of the body that plays remarkable roles in personality development, digestion, infection and many other physiological activities. An infectious tooth significantly contributes to poor oral hygiene. Oral health is correlated with many serious complications such as cardiovascular disease, diabetes, neurodegenerative diseases and many more. To maintain the clean teeth various materials or medicines have developed in the field of dentistry. Conventional dental materials often cause damage to the tooth properties, such as tooth whiteness, integrity and promote biofilm formation over the teeth. Taking the disadvantages of conventional materials into account, various nanomaterials have been developed for the application in the field of dentistry. Nanomaterials have the upper hand due to its small size, large surface area and easy to produce in large quantity. This chapter summarizes the current application of various nanoparticles in the field of dentistry.
Background
Particulate Hydroxyapatite (HAP; Ca5(PO4)3(OH)) is being increasingly used as multifunctional active ingredient in oral care. Due to its high similarity to human enamel crystallites, it is considered as a biomimetic agent.
Objective
The aim of this narrative review is to identify the modes of action of HAP in preventive oral health care based on published studies. The outcomes are expected to improve the understanding of the effects of HAP in the oral cavity and to provide a knowledge base for future research in the field of biomimetic oral care.
Methods
The data analyzed and discussed are primarily based on selected published scientific studies and reviews from in vivo, in situ, and in vitro studies on HAP in the field of preventive oral health care. The databases Cochrane Library, EBSCO, PubMed and SciFinder were used for literature search.
Results
We identified different modes of action of HAP in the oral cavity. They are mainly based on (I) Physical principles (e.g. attachment of HAP-particles to the tooth surface and cleaning properties), (II) Bio-chemical principles (e.g. source of calcium and phosphate ions under acidic conditions and formation of an interface between HAP-particles and the enamel), and (III) Biological principles (e.g. HAP-particles interacting with microorganisms).
Conclusion
Although more mechanistic studies are needed, published data show that HAP has multiple modes of action in the oral cavity. Since the effects address a wide range of oral health problems, HAP is a biomimetic agent with a broad range of applications in preventive oral health care.
Objective:
The present in situ - investigation aimed to specify the impact of pure hydroxyapatite microclusters on initial bioadhesion and bacterial colonization at the tooth surface.
Design:
Pellicle formation was carried out in situ on bovine enamel slabs (9 subjects). After 1min of pellicle formation rinses with 8ml of hydroxyapatite (HA) microclusters (5%) in bidestilled water or chlorhexidine 0.2% were performed. As negative control no rinse was adopted. In situ biofilm formation was promoted by the intraoral slab exposure for 8h overnight. Afterwards initial bacterial adhesion was quantified by DAPI staining and bacterial viability was determined in vivo/in vitro by live/dead-staining (BacLight). SEM analysis evaluated the efficacy of the mouthrinse to accumulate hydroxyapatite microclusters at the specimens' surface and spit-out samples of the testsolution were investigated by TEM.
Results:
Compared to the control (2.36?10(6)?2.01?10(6)bacteria/cm(2)), significantly reduced amounts of adherent bacteria were detected on specimens rinsed with chlorhexidine 0.2% (8.73?10(4)?1.37?10(5)bacteria/cm(2)) and likewise after rinses with the hydroxyapatite testsolution (2.08?10(5)?2.85?10(5)bacteria/cm(2), p<0.001). No demonstrable effect of HA-particles on Streptococcus mutans viability could be shown. SEM analysis confirmed the temporary adsorption of hydroxyapatite microclusters at the tooth surface. Adhesive interactions of HA-particles with oral bacteria were shown by TEM.
Conclusion:
Hydroxyapatite microclusters reduced initial bacterial adhesion to enamel in situ considerably and could therefore sensibly supplement current approaches in dental prophylaxis.
Using atomic force microscopy (AFM), we monitored the nanoscale surface morphology of human teeth at the dentin-enamel junction after performing successive demineralization steps with an acidic soft drink. Subsequently, we studied the remineralization process with a paste containing calcium and phosphate ions. Repeated AFM imaging of the same sample areas on the sample allowed us to draw detailed conclusions regarding the specific mechanism of the demineralization process and the subsequent remineralization process. The about 1-µm-deep grooves that are caused by the demineralization process were preferentially filled with deposited nanoparticles, leading to smoother enamel and dentine surfaces after 90 min exposure to the remineralizing agent. The deposited material is found to homogeneously cover the enamel and dentine surfaces in the same manner. The temporal evolution of the surface roughness indicates that the remineralization caused by the repair paste proceeds in two distinct successive phases.
In recent years, different agents have been discussed as potential alternatives to fluoride in the prevention of dental erosion. These agents are intended to form acid-resistant layers on the surface, to induce repair of eroded lesions by mineral precipitation or to prevent the enzymatic degradation of demineralised collagen. The application of adhesives and/or fissure sealants is considered to be an effective alternative to fluoride, but requires professional application and, depending on the product used, a re-sealing of the surface every several months. Studies testing film-forming products, such as polymers, have suggested the potential effectiveness of some of these approaches, such as chitosan, although further studies are needed to confirm the effectiveness of this approach. Other studies have demonstrated that products designed to deliver calcium and/or phosphate have not been successful at providing a significant anti-erosive effect. In advanced erosive lesions, the demineralised collagenous dentine matrix can be degraded by host enzymes such as matrix metalloproteinases (MMPs). As well as fluorides, epigallocatechin gallate and chlorhexidine have been identified as effective MMP inhibitors, with the potential to reduce the progression of dentine erosion. While fluoride compounds have been shown to have an anti-erosive potential, particularly those containing tin, alternative approaches that provide even greater protective capacity still need to be developed and proven to be effective. © 2014 S. Karger AG, Basel.
Context: Dentinal hypersensitivity (DH) is a commonly encountered problem. Several products are used in management of DH with varying results. Need is felt in dentistry for a material that chemically reacts, physically occludes and adheres intimately to dentinal tubules to reduce the possibility of its recurrence. One such material is calcium sodium phosphosilicate-Novamin ® .
Aim: To evaluate an efficacy of a 5% calcium sodium phosphosilicate (Novamin ® SHY NM TM ) containing dentifrice compared to placebo for the relief of DH.
Settings and Design: Outpatients visiting Dept of Periodontics, Yenepoya Dental College with DH were deemed eligible for this case-control clinical trial after an informed consent.
Materials and Methods: 30 patients having at least 2 sensitive teeth with a VAS (Visual Analogue Scale) of >3 cm after air blast stimulation, qualified to participate in the study. Test (SHY NM TM toothpaste containing 5% calcium sodium phosphosilicate) and control (Pepsodent toothpaste without a desensitizing agent) groups, each containing 15 participants, were subjected to cold water and air blast stimulation for an assessment of DH at baseline, 6 th and 8 th week using VAS.
Statistical analysis used: Unpaired t-test and repeated measures ANOVA.
Results: 5% Novamin ® containing dentifrice significantly reduced DH within 6 th and 8 th week of usage when compared to a placebo dentifrice.
Conclusions: A Novamin ® containing dentifrice significantly reduced DH when compared to a placebo dentifrice.
Surface kinetic roughening takes place both in case of growth and erosion processes. Teeth surfaces are eroded by contact with acid drinks, such as those used to supplement mineral salts during sporting activities. Calcium-phosphate based (CPP-ACP) pastes are known to reduce the erosion process, and to favour the enamel remineralization. In this study we used atomic force microscopy (AFM) to investigate the surface roughening during dental erosion, and the mechanisms at the basis of the protection role exerted by a commercial CPP-ACP paste. We found a statistically significant difference (p≪0.01) in the roughness of surfaces exposed and not exposed to the acid solutions. The treatment with the CPP-ACP paste determined a statistically significant reduction of the roughness values. By interpreting the AFM results in terms of fractal scaling concepts and continuum stochastic equations, we showed that the protection mechanism of the paste depends on the chemical properties of the acid solution.
Dentine remineralization is clinically significant for prevention and treatment of dentine caries, root caries, and dentine hypersensitivity. However, dentine remineralization is more difficult than enamel remineralization due to the abundant presence of organic matrix in dentine. The objective of this study was to develop a biomimetic method to facilitate remineralization of demineralized dentine through phosphorylation of type I collagen in demineralized dentine using sodium trimetaphosphate. The experimental results indicated that the effect of fluoride on remineralizing dentine was limited when residual mineral crystals were lacking on the surface of demineralized dentine, whereas the phosphorylation and Ca(OH)(2) pretreatment enhanced surface remineralization of the partially demineralized dentine. This biomimetic methodology resulted in favorable surface properties (i.e. highly negative charge and low interfacial free energy between substrate and aqueous medium) for crystal nucleation, and thus could be a promising method to remineralize superficially demineralized dentine lesions.
The objective of this eight-week, single-center, three-cell, double-blind, and randomized clinical study was to evaluate the dentin hypersensitivity reduction efficacy of three commercially available toothpastes: 1) Colgate Sensitive Pro-Relief Toothpaste (also marketed as elmex Sensitive Professional); 2) Sensodyne Rapid Relief Toothpaste; and (3) Crest Cavity Protection Toothpaste.
150 subjects, having two teeth with tactile and air blast hypersensitivity, were assigned to one of the three study groups (50/group). Subjects were then asked to brush their teeth for one minute, twice daily, with the given toothpaste. The dentin hypersensitivity and oral tissues were evaluated at baseline, two weeks, four weeks, and eight weeks. Comparison of the treatment groups with respect to gender was conducted using a chi-square analysis, and with respect to age and baseline hypersensitivity scores was performed using the analysis of variance (ANOVA). Within-treatment effects were analyzed using the paired t-test, while the analysis of covariance (ANCOVA) was used to examine between-treatment effects. The post hoc Tukey test was performed for pair-wise comparisons. All statistical tests were two-sided using a significance level of alpha = 0.05.
After two, four, and eight weeks of daily use of the products, all three groups showed a statistically significant reduction from baseline in tactile and air blast dentin hypersensitivity (p < 0.05). Colgate Sensitive Pro-Relief toothpaste produced a significant improvement in mean tactile and air blast dentin hypersensitivity scores, and was more effective than Sensodyne Rapid Relief toothpaste and Crest Cavity Protection toothpastes (p < 0.05).
Colgate Sensitive Pro-ReliefToothpaste, used twice daily, significantly reduces dentin hypersensitivity, and is significantly more effective in reducing dentin hypersensitivity than Sensodyne Rapid Relief Toothpaste and Crest Cavity Protection Toothpaste.
This in vitro study evaluated the effects of nano-hydroxyapatite (n-HAp) toothpastes on remineralization of bovine enamel and dentine subsurface lesions.
Specimens were demineralized, randomly divided into five groups, and exposed to an aqueous remineralizing solution for two and five weeks (37 °C). Brushing procedures were performed with the respective toothpaste/storage solution slurry twice daily (2 × 5 s; total contact time of the slurries 2 × 120s/d): storage in remineralizing solution only (0); additional brushing with B (20 wt% zinc carbonate nano-hydroxyapatite, ZnCO(3)/n-HAp); BS (24 wt% ZnCO(3)/n-HAp); E (0.14 wt% amine fluoride); or A (7 wt% pure n-HAp). Differences in mineral loss (ΔΔZ) before and after storage/treatment were microradiographically evaluated.
Dentine groups 0, B, BS, and A showed significantly higher ΔΔZ values compared to E (p < 0.05; ANOVA). Enamel ΔΔZ values of group A were significantly higher compared to group E (p < 0.05), whilst no significant differences of these groups could be observed compared to 0, B, and BS (p > 0.05).
With the in vitro conditions chosen, toothpastes containing n-HAp revealed higher remineralizing effects compared to amine fluoride toothpastes with bovine dentine, and comparable trends were obtained for enamel.
To present the results of an 8-week dentin hypersensitivity clinical study in which the efficacy of a new Pro-Argin formula toothpaste, with gentle whitening benefits, containing 8.0% arginine, a high cleaning calcium carbonate system, and 1450 ppm fluoride as sodium monofluorophosphate (MFP) was compared to that of a commercial Pro-Argin formula toothpaste containing 8.0% arginine, calcium carbonate, and 1450 ppm fluoride as MFP and a negative control toothpaste containing calcium carbonate and 1450 ppm fluoride as MFP.
An 8-week clinical study, with 121 subjects, was conducted in Chengdu, Sichuan, China, using a double-blind, stratified, three-treatment design. Tactile and air blast sensitivity assessments were used to compare the efficacy of the three products.
This clinical study demonstrated that the new Pro-Argin formula toothpaste provided a significant reduction in dentin hypersensitivity when used over a period of 8 weeks. The study also showed that the new toothpaste provided significantly greater reductions (P < 0.05) in dentin hypersensitivity in response to tactile (64.4%, 71.1%, and 61.0%) and air blast (40.7%, 58.8%, and 74.4%) stimuli than the negative control toothpaste containing 1450 ppm fluoride after 2, 4, and 8 weeks of product use, respectively. The results for the new toothpaste did not differ significantly from those of the positive control toothpaste at all time points in the study.
Purpose:
To provide an overview on diagnosis, risk factors and prevention of erosive tooth wear, which is becoming an increasingly important factor when considering the long- term health of the dentition.
Results:
Awareness of dental erosion by the public is still not widespread due to the cryptic nature of this slowly progressing condition. Smooth silky-glazed appearance with the absence of perikymata and intact enamel along the gingival margin, with cupping and grooving on occlusal surfaces are some typical signs of enamel erosion. In later stages, it is sometimes difficult to distinguish between the influences of erosion, attrition or abrasion during a clinical examination. Biological, behavioral and chemical factors all come into play, which over time, may either wear away the tooth surface, or potentially protect it. In order to assess the risk factors, patient should record their dietary intake for a distinct period of time. Based on these analyses, an individually tailored preventive program may be suggested to patients. It may comprise dietary advice, optimization of fluoride regimes, stimulation of salivary flow rate, use of buffering medicaments and particular motivation for non-destructive tooth brushing habits. The frequent use of fluoride gel and fluoride mouthrinse in addition to fluoride toothpaste offers the opportunity to minimize abrasion of tooth substance.
Milk and milk products, such as cheese, have been shown to exhibit anticariogenic properties in human and animal models. CPP-ACP shows an anti-caries effect by suppressing demineralization, enhancing remineralization, or possibly a combination of both. The purpose of this study was to evaluate the effect of CPP-ACP paste on demineralization by observing the treated tooth surface using an FE-SEM. The specimens were prepared by cutting enamel and dentin of bovine teeth into blocks. A few specimens were stored in 0.1 M lactic acid buffer solution for 10 min and then in artificial saliva (negative control). The remaining specimens were stored in a 10 times-diluted solution of CPP-ACP paste or a placebo paste containing no CPP-ACP for 10 min, followed by 10 min immersion in a demineralizing solution (pH = 4.75, Ca) twice a day before storage in artificial saliva. After treatment of the specimens for 3, 7, 21 and 28 days, they were fixed in 2.5% glutaraldehyde in cacodylate buffer solution, dehydrated in ascending grades of tert-butyl alcohol, and then transferred to a critical-point dryer. The surfaces were coated with a thin film of Au in a vacuum evaporator, and were observed under field emission-scanning electron microscopy (FE-SEM). The SEM observations revealed different morphological features brought about by the various storage conditions. Demineralization of the enamel and dentin surfaces was more pronounced with the longer test period in the control and negative control specimens. On the other hand, enamel and dentin specimens treated with CPP-ACP paste revealed slight changes in their morphological features. From the morphological observations of the enamel and dentin surfaces, it could be considered that the CPP-ACP paste might prevent demineralization of the tooth structure.
Objective:
To investigate how enamel loss due to erosion, and due to cycling of erosion and abrasion, depends on compositional parameters of soft drinks, and particularly whether the thickness of the erosive softened layer is a function of drink composition.
Setting:
University dental hospital research laboratory in the UK, 2004.
Materials and methods:
Six drinks were chosen based on their popularity and composition: apple juice, orange juice, apple drink, orange drink, cranberry drink and 'ToothKind' blackcurrant drink. Group A samples (n = 36) were exposed to soft drinks at 36 degrees C for six consecutive 10 minute periods. Group B samples (n = 36) were subjected to alternating erosion and toothbrushing, repeated six times. Enamel loss was measured using optical profilometry.
Results:
Group A: significant enamel loss was seen for all drinks (p < 0.001). Erosion was correlated with pH and calcium concentration but not phosphate concentration or titratable acidity. Group B: significant additional material loss due to toothbrush abrasion occurred with all drinks. Abrasive enamel loss differed between the drinks and was positively correlated with drink erosive potential.
Conclusion:
Enamel loss by erosion is exacerbated by subsequent abrasion. The amount of softened enamel removed by toothbrushing is a function of the chemical composition of the erosive medium.
Objective
The aim of the present study was to investigate the efficacy of a new preparation in dental prophylaxis containing zinc-carbonate hydroxyapatite microclusters (Biorepair) for oral biofilm management.
Methods and materials
Initial biofilm formation was carried out in situ with bovine enamel slabs fixed to individual upper jaw splints worn by six subjects. Rinses with the customary preparation as well as with subfractions (hydroxyapatite microclusters in saline solution; liquid phase without particles) were adopted for 1 min in situ after 1 min of pellicle formation, and the bacterial colonization was recorded after 6 h and 12 h, respectively. Rinses with chlorhexidine served as a reference. The adherent microorganisms were quantified and visualized using DAPI staining and live–dead staining (BacLight). Furthermore, the effects on Streptococcus mutans bacteria were tested in vitro (BacLight).
Results
Application of the customary preparation and of the separate components distinctly reduced the initial bacterial colonization of the enamel surface in situ as visualized and quantified with all techniques. After 12 h, 1.3 × 107 ± 2.0 × 107 bacteria/cm² were detected on unrinsed control samples with DAPI staining; 2.4 × 106 ± 3.3 × 106 after application of Biorepair (12 h after CHX-rinse; 1.3 × 105 ± 9.2 × 104). Also, pure hydroxyapatite microclusters in saline solution (2.1 × 106 ± 3.0 × 106) as well as the liquid phase without particles (5.1 × 105 ± 3.3 × 105) reduced the amount of adherent bacteria. Furthermore, antimicrobial effects on S. mutans were observed in vitro.
Conclusion
The preparation is an effective compound for biofilm management in the oral cavity due to antiadherent and antibacterial effects.
Clinical relevance
The tested mouthrinse seems to be a reasonable amendment for dental prophylaxis.
Dentine hypersensitivity occurs easily on exposed dentine. This study aimed to evaluate the effectiveness of a novel bioactive glass-containing toothpaste on dentine permeability and remineralization.
Thirty dentine discs were divided into three groups of 10 specimens each. The groups corresponded to the following brushing treatments: no brush, distilled water, and bioactive glass-containing toothpaste (Novamin). The toothpaste was applied twice a day for 7 days. Dentine permeability was measured after ethylene-diamine-tetraacetic acid (EDTA) etching, initial application, 3-day application, 7-day application and citric acid challenge, respectively. The dentine morphology was investigated using scanning electron microscopy (SEM). Attenuated total reflection Fourier transform infrared (ATR/FTIR) spectroscopy was performed to monitor the mineral variation on demineralized dentine. Qualitative information of elemental variation before and after treatments on completely demineralized dentine was detected by energy dispersive X-ray (EDX) analysis.
The bioactive glass-containing toothpaste significantly reduced dentine permeability after the 7-day treatment and showed, under SEM, excellent resistance to acid challenge compared to the other groups. ATR/FTIR and EDX revealed increased mineral content after treatment with Novamin.
As the innovative bioactive glass-containing toothpaste occlude dentinal tubules and resist acid challenge, it may be useful for the treatment of dentine hypersensitivity and dentine remineralization.
To examine the differences in the amounts of bound chlorhexidine (CHX) on demineralized dentine blocks and to investigate the different aspects of remineralization of demineralized dentine according to different concentrations of CHX.
Dentine blocks (2 mm × 7 mm × 0.9 m) were demineralized in 0.2 M formic acid solution. Amount of bound CHX on the dentine blocks was measured on a spectrophotometer after the dentine block was soaked in 0.02%, 0.2%, or 2% CHX solutions for 1 min. The change in elastic modulus of dentine block stored in simulated body fluids was measured at 0 (baseline), 2, 4, and 6 weeks after storage. The micromorphological aspects of the samples were observed using a field emission scanning electron microscope after 6 weeks of storage.
Higher concentrations of CHX caused a greater amount of CHX to bind to the dentine blocks (p<0.05). The group treated with the higher concentration of CHX had a smaller decrease in the elastic modulus at 2 weeks and a greater increase at 4 and 6 weeks. Dentine specimens with the 0.2% and 2% CHX had a greater deposition of granular minerals along the collagen fibrils compared to the 0.02% CHX-treated group.
The application of the 0.2% and 2% CHX seemed to be effective in promoting the remineralization of demineralized dentine.
The application of the 0.2% and 2% CHX positively influences on the dentine remineralization.
To evaluate the erosive potential of orange juice modified by food additives in enamel and dentine.
Calcium lactate pentahydrate (CLP), xanthan gum (XG), sodium linear polyphosphate (LPP), sodium pyrophosphate tetrabasic (PP), sodium tripolyphosphate (STP) and some of their combinations were added to an orange juice. Pure orange juice and a calcium-modified juice were used as negative (C-) and positive (C+) controls, respectively. In phase 1, 15 modified orange juices were tested for erosive potential using pH-stat analysis. In phase 2, the additives alone and the combination with good results in phase 1 and in previous studies (CLP+LPP) were tested in an erosion-remineralization cycling model. In phase 3, the erosion and remineralization episodes were studied independently. Enamel was analysed by surface microhardness (SMH) and profilometry, whilst dentine by profilometry.
In phase 1, reduction of the erosive potential was observed for all additives and their combinations, except XG alone. In phase 2, no detectable enamel loss was observed when CLP, LPP and CLP+LPP were added to the juice. XG, STP and PP had enamel loss similar to C- (p>0.05). Amongst additives, the combination CLP+LPP showed the highest SMH values followed by CLP (p<0.05). All the other groups presented SMH values similar to C- (p>0.05). For dentine, only CLP+LPP lead to surface loss values lower than C- (p<0.05). In phase 3, CLP, LPP and CLP+LPP seemed to protect against erosion; whilst none of the tested compounds seemed to interfere with the remineralization process.
CLP and LPP reduced erosion on enamel and this effect was enhanced by their combination. For dentine, only the combination CLP+LPP reduced erosion.
To characterize in vitro the formation and robustness of a layer formed on dentin following treatment with a fluoridated toothpaste containing calcium sodium phosphosilicate (NovaMin) using modem imaging and analysis techniques.
Calcium sodium phosphosilicate (CSPS)-containing toothpaste was brushed on to etched dentin specimens twice daily for up to five days. In between applications the samples were stored in artificial saliva. Additionally, certain samples underwent a chemical challenge in the form of a dietary acid, whereby samples were exposed to a cola or grapefruit juice beverage for five minutes on day 4 of the five-day study. The ability of the CSPS-containing formulation to occlude tubules was assessed visually by scanning electron microscope (SEM) imaging and compared to a water control. In a second experiment, the mechanical resistance of the layer was assessed using profilometry after controlled brushing for 200 brush strokes with a wet medium-bristled toothbrush. To visualize the layer and characterize the tubule occlusion, longitudinal cross-sections were prepared using a focused ion beam scanning electron microscope (FIB SEM), and analysis performed by energy dispersive x-ray spectroscopy (EDS) and electron diffraction. Owing to the complexity of the mixed material deposited after application of the toothpaste, material from inside a dentin tubule was selectively removed after five days of treatment, and the morphologically different materials imaged and analyzed by electron diffraction in the transmission electron microscope (TEM).
SEM inspection showed significant coverage of the dentin samples after application of CSPS toothpaste for all five days, in contrast to the water control where the majority of tubules remained open after all five days. Exposure of the NovaMin-treated samples to common dietary acids did not lead to re-exposure of the tubules. Profilometry measurements demonstrated an intact layer covering the dentin surface after one and five days. EDS analysis and electron diffraction indicated the layer and the material plugging the tubule to be a calcium phosphate material with a crystallographic structure similar to hydroxyapatite.
CSPS contained in toothpaste formulations adhered to exposed dentin surfaces. The layer formed was resistant to acid and mechanical challenges. Characterization of this layer indicated it was hydroxyapatite-like in nature.
This study sought to gain insights into the surface structural and mechanical changes leading to remineralization of dentin. Remineralization was compared between a continuous remineralization approach and a nonbuffered static approach using solutions of the same initial composition. Artificial carious lesions were treated for 5 days and analyzed every 24 h using nanoindentation in water, SEM, and AFM. The continuous approach yielded a recovery of mechanical properties of up to 60% of normal dentin, whereas the static approach led to recovery of only 10%. Image analysis revealed that the static approach yielded the formation of areas suggestive of an apatite precipitate on the surface of the dentin matrix. In contrast, surface precipitate was absent using the continuous approach, suggesting that mineral formed within the lesion and re-associated with the collagenous matrix. This study provided evidence that mechanical recovery of dentin in near physiological conditions is attainable through the continuous delivery of calcium and phosphate ions.
The purpose of this in vitro study was to evaluate the effect of toothpastes containing sodium fluoride in different concentrations or a calcium sodium phosphosilicate system on pre-softened dentin demineralization and remineralization.
During a ten day pH-cycling protocol, pre-softened bovine root dentin slabs were immersed twice daily, after the demineralization periods, for 2min, in the following toothpaste slurries: (a) non-fluoridated (control), (b) 7.5% calcium sodium phosphosilicate, (c) 1450 ppm F, (d) 2800 ppm F and (e) 5000 ppm F. Subsequently, the specimens were subjected to a 15-h acid resistance test. Surface microhardness was assessed initially and during the pH-cycling and the acid resistance test period. Repeated measurements in each group were analyzed through appropriate regression models for longitudinal data.
All fluoride groups, during pH cycling, showed significantly less microhardness loss (p < or = 0.010, p < or = 0.002, p < or = 0.002) and subsequently exhibited increased acid resistance (p < or = 0.010, p < or = 0.001, p < or = 0.001) compared to the control. The 5000 ppm and 2800 ppm F toothpastes, inhibited demineralization significantly more effectively than the 1450 ppm F (p < or = 0.001, p < or = 0.030) and the calcium sodium phosphosilicate toothpaste (p < or = 0.001), while no significant differences were found between the two high fluoride groups (p=0.130). The calcium sodium phosphosilicate toothpaste, during pH cycling showed a difference that approached statistical significance compared to control (p=0.079), but its acid resistance behavior was similar to control (p=0.610).
Under these experimental conditions, the high fluoride toothpastes promoted remineralization and inhibited demineralization more effectively, than the 1450 ppm F, the non-fluoridated (control) and the calcium sodium phosphosilicate toothpastes.
The aim of the present in vitro study was the evaluation of a CPP-ACP paste (Tooth Mousse) on preventing dental erosion produced by a soft drink (Coca Cola), using Atomic Force Microscopy (AFM).
Thirty extracted human central incisors free of caries were selected and divided in a treatment and a control half. The treatment halves were divided in three groups-group 1: demineralization with soft drink (4 intervals of 2 min); group 2: demineralization with soft drink (4 intervals of 2 min) plus Tooth Mousse; group 3: intact enamel plus Tooth Mousse. In groups 2 and 3 Tooth Mousse was applied for 3 min at 0, 8, 24 and 36 h. The surface of each specimen was imaged by AFM and R(rms) values were registered.
Among treatment specimens of groups 1 and 2, a statistically significant difference (P<0.01) in R(rms) values was registered: treatment of the specimens with CPP-ACP paste had a protective effect on enamel demineralization. In group 3 no statistically significant difference was registered between exposed and not exposed halves of the specimens.
The use of a CPP-ACP paste had a protective effect on enamel demineralization in an in vitro model.
The study aimed to evaluate, (a) the surface morphology of acid etched/conditioned enamel following carbamide peroxide bleaching with/without casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) (Tooth Mousse (MI Paste); GC Corp., Tokyo, Japan) treatment; and b) the nature of the bonded resin-enamel interfaces formed with a self-etching primer adhesive.
Twenty-four human adult molars were each sectioned into four, the specimens divided and treated according to four experimental groups: 1, no treatment; 2, 16% carbamide peroxide bleaching; 3, CPP-ACP paste; 4, bleaching and CPP-ACP paste. A self-etching primer adhesive (Clearfil SE Bond, CSE) was used. The specimens were further divided into four subgroups for etching/conditioning: A, CSE Primer only; B, 30-40% phosphoric acid and CSE primer; C, 15% EDTA and CSE primer; D, 20% polyacrylic acid and CSE primer. Bonded specimens were also prepared. The morphology of the etched/conditioned enamel surfaces and polished resin-enamel interfaces of the bonded specimens were observed by field-emission scanning electron microscopy (FE-SEM).
Treatment with CPP-ACP did not inhibit phosphoric acid etching of enamel. Poorly defined enamel etch patterns were observed with the other conditioners in all the groups. The morphology of the bonded resin-enamel interfaces observed on FE-SEM for each acid etching/conditioning subgroup was similar in all the experimental groups, except after bleaching. Resin infiltration into enamel was observed with prior phosphoric acid etching and polyacrylic acid conditioning and was unaffected by experimental group treatments.
The use of a CPP-ACP paste with or without prior bleaching did not inhibit enamel etching. Enamel etching/conditioning may help improve bonding efficiency of the self-etching primer adhesive after CPP-ACP treatment.
In addition to its role as a remineralizing agent in preventing dental caries, calcium product (CPP-ACP) delivered as a mousse (Tooth Mousse, TM) can reduce erosion of enamel and dentine. The aim of this study was to determine whether CPP-ACP could also reduce erosive tooth wear involving toothbrush abrasion.
Flat, polished enamel and dentine specimens (n=72) were subjected to 10 wear regimes, with each regime involving erosion in 0.3% citric acid (pH 3.2) for 10 min followed by toothbrush abrasion in a slurry of fluoride-free toothpaste and artificial saliva (1:3 ratio by weight) under a load of 2N for 200 cycles. The specimens were immersed in artificial saliva for 2h between wear regimes. In the experimental group 1, TM (containing CPP-ACP) was applied at the beginning of each wear episode for 5 min whereas TM- (without CPP-ACP) was applied in the experimental group 2. No mousse was applied in the control group.
TM significantly reduced enamel wear (mean+/-S.E., 1.26+/-0.33 microm in the experimental group 1 vs 3.48+/-0.43 microm in the control group) and dentine wear (2.16+/-0.89 microm in the experimental group 1 vs 10.29+/-1.64 microm in the control group), and dentine wear was significantly less in the experimental group 1 than in the experimental group 2 (5.75+/-0.98 microm).
The finding that TM reduced erosive tooth wear involving toothbrush abrasion, probably by remineralizing and lubricating eroded tooth surfaces, may have implications in the management of tooth wear.
Using laboratory, animal, and human in situ caries models, investigators have shown that casein phosphopeptide amorphous calcium phosphate complexes (CPP-ACP) exhibit an anticariogenic activity. The casein phosphopeptides (CPP) are produced from a tryptic digest of the milk protein casein by aggregation with calcium phosphate and purification by ultrafiltration. The CPP have a remarkable ability to stabilize calcium phosphate in solution and substantially increase the level of calcium phosphate in dental plaque. Through their multiple phosphoseryl residues, the CPP bind to forming clusters of amorphous calcium phosphate (ACP) in metastable solution, preventing their growth to the critical size required for nucleation and precipitation. The proposed mechanism of anticariogenicity for the CPP-ACP is that they localize ACP in dental plaque, which buffers the free calcium and phosphate lon activities, thereby helping to maintain a state of supersaturation with respect to tooth enamel depressing demineralization and enhancing remineralization. The CPP-ACP, unlike fluoride, can be added to sugar-containing foods and therefore have commercial potential as an additive to foods as well as to toothpastes and mouthwashes for the control of dental caries.
Atomic force microscopy (AFM) was used to study tooth surfaces in order to compare the pattern of particle distribution in the outermost layer of the tooth surfaces. Human teeth and teeth from a rodent (Golden hamster), from a fish (piranha), and from a grazing mollusk (chiton) with distinct feeding habits were analyzed in terms of particle arrangement, packing, and size distribution. Scanning electron microscopy and transmission electron microscopy were used for comparison. It was found that AFM gives high-contrast, high-resolution images and is an important tool as a source of complementary and/or new structural information. All teeth were cleaned and some were etched with acidic solutions before analysis. It was observed that human enamel (permanent teeth) presents particles tightly packed in the outer surface, whereas enamel from the hamster (continuously growing teeth) shows particles of less dense packing. The piranha teeth have a thin cuticle covering the long apatite crystals of the underlying enameloid. This cuticle has a rough surface of particles that have a globular appearance after the brief acidic treatment. The similar appearance of the in vivo naturally etched tooth surface suggests that the pattern of globule distribution may be due to the presence of an organic material. Elemental analysis of this cuticle indicated that calcium, phosphorus, and iron are the main components of the structure while electron microdiffraction of pulverized cuticle particles showed a pattern consistent with hydroxyapatite. The chiton mineralized tooth cusp had a smooth surface in an unabraded region and a very rough structure with the magnetite crystals (already known to make part of the structure) protruding from the surface. It was concluded that the structures analyzed are optimized for efficiency in feeding mechanism and life span of the teeth.
The aim of the present study was to evaluate the effect of three peroxide-containing bleaching agents, Opalescence, Nite White and a 30% hydrogen peroxide solution, on enamel surfaces using Atomic Force Microscopy (AFM).
Fifteen non-carious human incisors (ten maxillary and five mandibular, extracted for periodontal reasons) were used. The teeth were divided randomly into three groups of five, according to the bleaching agents. The labial surface of each tooth was imaged by AFM before and after treatment. Each bleaching agent was applied for a total of 28 h (in individual 4 h treatments). The specimens were examined only after 28 h of treatment.
On comparing the AFM images of untreated and treated enamel, surface alterations were observed after 28 h of treatment with Opalescence, Nite White and 30% hydrogen peroxide solution. Several grooves present in the enamel surface of untreated teeth became deeper after the bleaching procedure. The depths of the grooves increased in each case. The increase in the depth of grooves was more pronounced in the case of the 30% H2O2 solution.
Home-use bleaching agents are capable of causing enamel surface alterations. It is hypothesized that the peroxide-containing bleaching agents affect the organic phase of enamel. Peroxides can affect not only the surface but also the inner structure of enamel. As a result of its low molecular weight, hydrogen peroxide can penetrate into the enamel. Thus, inner oxidative effects are more likely to occur in the subsurface enamel where more organic material is present and oxidation is capable of altering the outer enamel and the surface.
Atomic force microscopy (AFM) has been used to determine microstructural changes, etching rates of peritubular dentin, and intertubular dentin recession during demineralization in dilute acidic solutions. These studies have not included many forms of altered dentin, including noncarious sclerotic root dentin associated with Cl V (abfraction) lesions. We sought to determine microstructural changes and recession rates during demineralization in citric acid (pH 2.5, 0.018M) for the transparent/sclerotic zone. Highly polished dentin disks were prepared from teeth with noncarious C1 V lesions (n = 3) and compared with normal root dentin (n = 3). Samples were etched at 5-s intervals for 1 min and at longer intervals up to 30 min. The depth changes in various portions of the dentin with respect to the reference layer were measured and changes in microstructure observed in solution in the wet cell of the AFM. In sclerotic dentin, most tubule lumens were occluded with crystalline deposits that etched more slowly than the other dentin components, but etching rates could not be determined due to their irregular geometry. The intertubular dentin recession quickly reached a plateau after a depth change of <1 microm for all dentin types, in agreement with prior work. Mixed linear regression models indicated an important difference between the etching of sclerotic intertubular dentin and that of non-sclerotic root dentin that became apparent after 600 s (p = 0.037). The sclerotic intertubular dentin underwent less depth change at the plateau (558 nm) compared to normal root dentin (744 nm). In addition, normal root dentin underwent significantly greater recession than coronal dentin (p = 0.002). The results of this study indicate that intertubular sclerotic dentin from Cl V lesions etches differently than normal root dentin, and this may help explain the difficulties in restoring such lesions with current bonding procedures.
Food-induced demineralization (erosion) is one of the key factors in surface structural changes of tooth enamel, with soft drinks being a significant etiological agent. The objective of this study was to measure early stages of enamel loss with high accuracy on native enamel surfaces combined with qualitative observations of changes in the surface morphology using the atomic force microscope (AFM). Native unerupted third molar surfaces were partly covered with a gold reference layer. Samples were imaged with the AFM before dissolution (at baseline) and after exposure to three different drinks (mineral water, a "toothkind" blackcurrant drink, and a lemon and lime juice drink) at five different exposure times (15 min, 30 min, 1 h, 2 h, and 3 h). The changes in the surface morphology were investigated qualitatively as well as quantitatively. This study showed that the maximum material loss occurred at the aprismatic parts of the enamel close to the perikymata. The maximum enamel loss was greatest for the lemon and lime juice drink and lowest for water. A two-way ANOVA of the transformed data, employing the natural logarithm, showed a statistically significant difference between both the drinks and the exposure time at a 95% confidence level (P=0.000). This demonstrates that the AFM is a suitable tool for measuring early stages of enamel demineralization. Copyright 2000 Academic Press.
The purpose of this study was to compare the caries preventive efficacy of a mouthrinse solution containing casein derivatives coupled with calcium phosphate (CD-CP) with that of a 0.05% sodium fluoride mouthrinse among individuals with dry mouth.
A randomized control trial design was used. Participants included individuals who had had radiotherapy for head and neck cancer (n = 82) and others with Sjögren's syndrome (n = 56). Baseline data collection was followed by reexamination 12 months later. Posterior bite-wing radiographs were taken on both occasions.
A total of 124 participants, 61 (49.2%) in the sodium fluoride group and 63 (50.8%) in the CD-CP group, completed the 12-month examination. The baseline characteristics of the 2 groups did not differ. Coronal caries incidence was higher in the sodium fluoride group than in the CD-CP group (34.4% and 27%, respectively), but the difference was not statistically significant. Similarly, the small difference in coronal caries increment between the 2 groups was not statistically significant (0.4 and 0.3 surfaces, respectively). There was insufficient root surface caries experience between the 2 groups observed for differences to be examined. Proportionately more of the CD-CP group lost 1 or more teeth, and the mean number of tooth loss was higher. The participants with the highest incidence and increment were those with Sjögren's syndrome in the CD-CP group. Some of that difference was accounted for by differences in baseline caries status.
It appears that CD-CP preparations hold promise as caries preventive agents for individuals with dry mouth, although confirmation of this study's findings in other settings is warranted before a definitive conclusion can be reached.
It is widely held that the hardness and modulus of dentin increase in proportion to the mineral concentration. To test this belief, we measured hardness and modulus of normal dentin and an altered form of dentin without gap-zone mineralization in wet and dry conditions by AFM nanoindentation to determine if the modulus and hardness scale linearly with mineral concentration. Mineral concentrations in the mid-coronal location of the normal and altered dentins were 44.4 vol% and 30.9 vol%, respectively. Surrounding the pulp of the altered dentin was a region of higher mineralization, 40.5 vol%. The indentation modulus of normal dentin was 23.9 (SD = 1.1) GPa dry and 20.0 (SD = 1.0) GPa wet. In mid-coronal regions of the altered dentin, the indentation modulus was 13.8 (SD = 2.0) GPa dry and 5.7 (SD = 1.4) GPa wet. In the more mineralized regions of the altered dentin, the modulus was 20.4 (SD = 1.8) GPa dry and 5.3 (SD = 0.8) GPa wet; the properties of the altered wet dentin did not correlate with mineral concentration. The results of this study raise doubt as to whether mineral concentration alone is a sufficient endpoint for assessing the success or failure of remineralization approaches in restorative dentistry.
Acids of intrinsic and extrinsic origin are thought to be the main etiologic factors for dental erosion. There is evidence that acidic foodstuffs and beverages play a role in the development of erosion. However, the pH of a dietary substance alone is not predictive of its potential to cause erosion as other factors modify the erosive process. These factors are chemical (pKa values, adhesion and chelating properties, calcium, phosphate and fluoride content), behavioural (eating and drinking habits, life style, excessive consumption of acids) and biological (flow rate, buffering capacity, composition of saliva, pellicle formation, tooth composition, dental and soft tissue anatomy). The interplay between erosion and abrasion (specially oral hygiene practices) may be the main driver leading to the clinical manifestation of this disorder. Recommendations for patients at risk for dental erosion such as reducing acid exposure by reducing the frequency and contact of acids will be discussed.
The aim of this study was to compare the accuracy of approximal caries lesion depth measurements in radiographs from four digital systems. Two CCD-based sensors, Dixi (Planmeca) and Sidexis (Sirona), and two phosphor plate systems, Digora (Soredex) and DenOptix (Gendex), were used to record radiographs of 177 extracted human teeth. Sixty-four radiographically visible lesions were selected and measured by 4 observers in the digital radiographs and in digital photographs of histological sections of the teeth. The gold standard (true measure) was defined as the mean of the 4 observers' measurements on the histological sections. Two untrained observers underestimated general lesion depth in all the radiographic systems while each of 2 trained observers underestimated the depth in one of the systems. Analysis of variance revealed that Digora images resulted overall in the smallest underestimation, followed by Dixi, DenOptix and Sidexis. The differences between Digora and Sidexis and between Dixi and Sidexis were statistically significant (p < 0.05). Analysis of variance using the regression coefficient as the test variable demonstrated that the coefficients differed between DenOptix and the remaining systems (p < 0.05) while there were no significant differences between these (p > 0.05). It can be concluded that radiographs obtained with the Dixi and Digora systems were more accurate than Sidexis and DenOptix images for measurement of caries lesion depth. Still, a high probability exists that the individual lesion measurement is either overestimated or underestimated compared to the true lesion depth.
Objectives. To review the various methods and techniques available to assess enamel erosion in vitro. Data. Peer reviewed scientific articles. Sources. Medline and Web of Science searches and manual searching. Study selection. Laboratory based assessments only included. Conclusions. A number of macroscopic and microscopic techniques have been used to assess enamel erosion in vitro and in situ. This review examines techniques which are either well established or comparatively novel techniques that are being explored for their potential.
The objective of this study was to investigate human enamel erosion under constant composition conditions, as a function of solution degree of saturation (DS) with respect to hydroxyapatite. The experimental conditions were relevant to the initial stages of enamel erosion by soft drinks. Nanoindentation was used to compare enamel surface softening caused by a control mineral water and two citric acid solutions with DS = 0.000 and DS = 0.032, both having pH 3.30. Enamel hardness and reduced elastic modulus were measured after 0, 30, 60, 120, 300 and 600 s exposure. A statistically significant change in enamel hardness was detected after 30 s exposure to both citric acid solutions, indicating that nanoindentation is extremely sensitive to the initial stages of erosion. There was a statistically significant difference between the mechanical properties of enamel exposed to the two citric acid solutions after 30, 60 and 120 s. At these times, the solution with DS = 0.000 caused twice as much enamel softening as that with DS = 0.032. This demonstrates that it may be possible to design a soft drink with a low erosive potential and a good taste by a small change in DS, at a typical drink pH.
Enamel erosion can occur with frequent consumption of sports drinks. The purpose of this study was to determine a minimal concentration of casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) which when added to a sports drink would eliminate such erosion in vitro.
Human enamel specimens were immersed in: (1) the sports drink Powerade; (2) Poweradeplus 4 concentrations of CPP-ACP (0.063%, 0.09%, 0.125%, 0.25%); or (3) double deionized water. Windows of test and control enamel were profiled, and the enamel surface characteristics were examined under scanning electron microscopy (SEM).
The pH of test solutions increased and the titratable acidity decreased with increasing CPP-ACP concentrations. Erosive step lesions occurred in specimens immersed in Powerade (mean depth=38.70kA +/- 5.60), which were eliminated by the addition of CPP-ACP to Powerade at all test concentrations except 0.063% CPP-ACP. Microscopic surface irregularities on test enamel were observed, apparent as adherent granules or globules. These may represent redeposited mineral phases following mobilization of calcium and phosphate from CPP-ACP. Tasters in a taste panel could not distinguish Powerade from Powerade plus 0.125% CPP-ACP.
Adding casein phosphopeptide-stabilized amorphous calcium phosphate to the sports drink Powerade significantly reduced the beverage's erosivity without affecting the product's taste.
The purpose of this study was to determine the effect of Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) paste on demineralization of bovine enamel by measuring changes in the ultrasound transmission velocity.
The enamel specimens were prepared by cutting bovine teeth into blocks. The specimens were stored in 0.1 M lactic acid buffer solution (pH 4.75, Ca 0.75 mM, P 0.45 mM) for 10 min twice a day, and then stored in the artificial saliva (pH 7.0). Other specimens were stored in a 10-times diluted solution of CPP-ACP paste and a placebo paste without CPP-ACP for 10 min, followed by 10 min immersion into a demineralization solution twice a day before storage in the artificial saliva. The propagation time of longitudinal ultrasonic waves was measured by a Pulser-Receiver (Model 5900, Panametrics) with a transducer (V112, Panametrics). Six specimens were used for each condition, and one-way ANOVAs followed by the Tukey HSD tests (alpha = 0.05) were done.
The sonic velocity was found to decrease with time for specimens stored in the demineralization solution. On the other hand, a significant increase in sonic velocity was found for specimens stored in the CPP-ACP solution.
From the result of this study, it was suggested that the conditions of de- and remineralization of the enamel structure could be measured non-destructively by using an ultrasonic pulse method. It could be concluded that the inorganic components contained in high concentrations in CPP-ACP acted to enhance remineralization of the enamel structure.
Investigations of the erosive potential of soft drinks are usually performed at room or body temperature, but drinks are more frequently served chilled, with ice, or hot. Since the rate of chemical reactions usually increases with temperature, it is predicted that erosion is more severe at high temperatures and reduced at low temperatures. The aim of this study was to investigate the correlation between enamel softening, enamel erosion, and temperature.
Atomic force microscopy nanoindentation and non-contact optical profilometry were used to assess changes in enamel nanomechanical properties after 5 min and erosive material loss after 30 min exposure to two different non-carbonated soft drinks at 4, 25, 50 and 75 degrees C.
For one drink (Robinson's Original Juice Drink), there was a statistically significant difference between nanomechanical properties and erosion depth at all temperatures, with softening and erosion increasing with temperature. For another drink (Ribena ToothKind Juice Drink), there was a slight softening and virtually no material loss, and temperature had no statistically significant impact on erosion. There was a good linear correlation (R2 = 0.94) between nanomechanical properties and material loss.
The difference between the drinks can be explained by their composition. For the erosive drink, material loss increased, and nanohardness decreased, approximately linearly with temperature. The correlation between softening and erosion demonstrated that nanomechanical properties after very short erosion times can be considered a good predictor of bulk material loss after considerably longer erosion times.
Etching is one of the most fundamental steps in the restoration of teeth by adhesion of composite resin in dental clinics. Atomic force microscope (AFM) was used for the in situ observation of the etching process of human enamel, dentin and synthetic hydroxyapatite in the three different acid agents, 2% phosphoric acid, 10% citric acid and 10% polyacrylic acid. To measure the absolute depth from the initial level before etching and to correlate the surface height between the changing AFM images obtained, the depth profiles were recorded with etching time by carrying out the line scan consecutively at the representative place of the observed area. These chronological series of depth profiles enabled us to perform quantitative analysis of etched amount in addition to the surface roughness obtained from relative depth profile within one image. The course of etching process from the dissolution of smear layer, appearance of enamel prizms or dentinal tubules to progress of demineralization could clearly be observed. The depth profile, surface roughness, etching amount, etching rate and smear layer thickness could then be evaluated. The different etching characteristics of three acid agents and the effect of surface roughness produced by different mechanical prepolish were compared and discussed.
To explore the potential of atomic force microscopy (AFM) for the examination of changes to dentine surfaces during demineralization and evaluate qualitatively the effect of EDTA, EDTAC and citric acid.
Nine canine teeth were sectioned transversely at the cemento-enamel junction, and the crowns discarded. Subsequently, each root was embedded in an epoxy cylinder and discs approximately 5 mm thick were cut. A standard metallographic procedure was then used to prepare the surfaces for observation. From the central portion of these samples, two specimens were symmetrically prepared per tooth so that a total number of 18 samples was produced. To allow the use of a liquid cell during AFM, the samples were embedded in silicone rubber and were then randomly divided into three groups, as follows: group 1: 17% EDTA (pH 7.7), group 2: 17% EDTAC (pH 7.7) and group 3: 10% citric acid (pH 1.4). Topographical images were acquired during the demineralization process, allowing real-time observation of the dentine surface. Two operators assigned scores to the AFM images using a double-blind method. anova analysis with random effects (P < 0.05) was used to compare the results.
The average scores were 6.13 +/- 0.35 for EDTAC, 7.36 +/- 0.23 for EDTA and 14.55 +/- 1.21 for citric acid. Citric acid was statistically different from EDTA and EDTAC while EDTA and EDTAC were not statistically different.
The most effective demineralizing substance was citric acid. The methodology developed for real-time observation of dentine surfaces is a valuable method to evaluate demineralization.
This in situ/ex vivo study assessed the effect of fluoride dentifrice on eroded enamel subjected to brushing abrasion. In a crossover study performed in 2 phases, 10 volunteers wore acrylic palatal appliances, each containing 3 human enamel blocks. Dentifrice was used to brush the volunteers' teeth and the specimens subjected to abrasion. In phases A and B the dentifrices used had the same formulation, except for the absence or presence of fluoride, respectively. The blocks were subjected to erosion by immersion of the appliances in a cola drink for 5 min, 4 times a day. Then the blocks were brushed, and the appliance was replaced into the mouth. Enamel alterations were determined using profilometry and percentage change in surface microhardness (%SMHC) tests. The data were tested using the paired t test. The mean wear values (+/-SD, microm) were: group A 6.84 +/- 1.72 and group B 5.38 +/- 1.21 (p = 0.04). The mean %SMHC values (+/-SD) were: group A 54.6 +/- 16.2 and group B 45.7 +/- 6.8 (p = 0.04). Fluoride dentifrice had a protective effect on eroded enamel subjected to brushing abrasion.
This in vitro study used surface microhardness to evaluate whether a paste containing casein phosphopeptide amorphous calcium phosphate (CPP-ACP) can reharden tooth enamel softened by a cola drink, and how different saliva-substitute solutions affect the enamel hardness.
Twenty-four bovine incisors, each tooth consisting of treatment and control halves, were immersed in a cola drink (Coke) for 8 min, then placed under a 0.4 mL/min drip with various saliva-substitute solutions. The saliva-substitute solutions were: saliva-like solution (SLS) with 1 ppm fluoride, SLS without fluoride, and Biotene mouthwash. CPP-ACP paste was applied to the treatment halves for 3 min at 0, 8, 24, and 36 h. Knoop microhardness measurements were performed at baseline, after the cola drink immersion, and after 24 and 48 h contact with saliva-substitute solution.
Enamel hardness significantly decreased after immersion in cola drink (ANOVA, p<0.05). After contact with saliva-like solutions for 48 h, those treated with CPP-ACP paste were significantly harder than those untreated regardless of the presence of 1 ppm fluoride in the saliva-like solution (ANOVA, p<0.05). Biotene mouthwash significantly softened the enamel surface (ANOVA, p<0.05). Two-way ANOVA showed significant effects of the CPP-ACP paste application and types of saliva-substitute solutions on the changes in surface hardness of the softened enamel at a significance level of 0.05.
The application of CPP-ACP paste with continuous replenishment of saliva-like solution for 48 h significantly hardened enamel softened by a cola drink. Biotene mouthwash softened enamel surface after 48 h contact.
The relationship betweenenamelsofteninganderosioncausedbysoftdrinksat a range of temperatures
- Me Barbour
- M Finke
- Parker
- Dm
Barbour ME, Finke M, Parker DM, et al. 2006. The relationship betweenenamelsofteninganderosioncausedbysoftdrinksat a range of temperatures. J Dent 34:207–213
Citric acid etching of cervical sclerotic dentin lesions: an AFM study
- Marshall