Influence of different ultra-soft toothbrushes on erosive tooth wear.

OBJECTIVE: To investigate the influence of different ultra-soft toothbrushes on the progression of erosive tooth wear (ETW). METHODS: Bovine enamel and dentin specimens (n = 10) were submitted to a 5-day erosive-abrasive cycling model (0.3% citric acid for 5 min, artificial saliva for 60 min, 4x/day). Toothbrushing was carried out 2x/day for 15 s, with the different toothbrushes tested (A- Edel White: flexible handle, tapered bristles; B- Oral-B Gengiva Detox: regular handle, criss-cross tapered bristles; C- Colgate Gengiva Therapy: flexible handle, tapered bristles, high tuft density; d- Oral-B Expert Gengiva Sensi: regular handle, round end bristles, high tuft density; E- Oral-B Indicator Plus: soft brush, round end bristles (control). Surface loss (SL, in µm) was assessed by optical profilometry. The toothbrush characteristics were evaluated by a surgical microscope. Data were statistically analyzed (α=0.05). RESULTS: For enamel, toothbrush C showed the highest SL (means±SD: 9.86 ± 1.28) and it did not differ significantly from A (8.60 ± 0.50), both with flexible handles. The lowest SL was observed for the toothbrush Control E (6.76 ± 0.63), which differed significantly from A and C, but not from the other toothbrushes. For dentin, the highest SL was found for toothbrush D (6.97 ± 1.05) and it did not differ significantly from E (6.23 ± 0.71). The lowest SL was observed for B (4.61 ± 0.71) and C (4.85 + 0.83), without significant differences from A (5.01 ± 1.24). CONCLUSIONS: The ultra-soft toothbrushes had different impacts on the progression of ETW on the dental substrates. On enamel, higher ETW values were observed for the flexible handle toothbrushes, while for dentin, round-end bristles (ultra-soft and soft) caused more ETW. CLINICAL SIGNIFICANCE: Knowledge about the effect of different ultra-soft toothbrushes on ETW can help clinicians to recommend the most suitable types for their patients, bearing in mind that toothbrushes can impact enamel and dentin differently.

Patient care in the restorative clinic of a public dental school after COVID-19 lockdown

Aim: This study, with the aim of checking some of the changes in patients' daily habits and their reasons for needing restorative treatment was conducted at a public university immediately on return to attendance after the COVID-19 pandemic lockdown. Methods: This survey consisted of interviews held by applying 2 questionnaires to students and patients. A single researcher collected data in all the restorative dentistry clinics at the university after the return to face-to-face activities in the period between 02/02/2021 and 07/30/2021. Data obtained by means of the questionnaires were submitted to descriptive analysis. Results: Ninety (90) participants answered the patient questionnaire. When considering possible associations between being in social isolation or not, significant values were found for changed type of diet (p=0.0011), frequency of eating (p=0.011) and toothbrushing (p=0.034). Data about 417 restorations were collected and among the reasons for restorative intervention, 33.03% were restoration replacement, 31.87% treatment of primary caries and 24.40% of dental wear/non-carious lesions. Conclusion: Patients who isolated themselves during the pandemic tended to change their eating habits and frequency of oral hygiene. Toothache was the main reason for seeking dental treatment and the replacement of pre-existing restorations was the main reason for restorative treatments

Erosive tooth wear inhibition by hybrid coatings with encapsulated fluoride and stannous ions.

This study aimed to formulate a hybrid coating material (HC) and to modify this HC with fluoride (NaF) and stannous (SnCl2) ions, directly or encapsulated in nano containers, testing the effects of these materials against dental erosion and erosion-abrasion. Enamel and dentin specimens were treated with the HCs, and then tested in erosion or erosion-abrasion cycling models of 5 days (n = 10 for each substrate, for each model). Deionized water was the negative control, and a fluoride varnish, the positive control. Surface loss (SL, in µm) was evaluated with an optical profilometer, and data were statistically analyzed (α = 0.05). For enamel, in erosion, the positive control and HC without additives showed significantly lower SL than the negative control (p = 0.003 and p = 0.001). In erosion-abrasion, none of the groups differed from the negative control (p > 0.05). For dentin, in erosion, the positive control, HC without additives, HC with non-encapsulated F, and HC with encapsulated F + Sn showed lower SL than the negative control (p < 0.05). In erosion-abrasion, none of the groups differed significantly from the negative control (p < 0.05). HC without additives showed a promising potential for protecting the teeth against dental erosion (with upward trend for improved protection on dentin), but not against erosion-abrasion. The presence of additives did not improve the protective effect of the HC, on both substrates.

Chemical and mechanical resistance of novel experimental hybrid coatings on dentin permeability.

This study aimed to evaluate the capacity of novel experimental hybrid coatings (HC) to reduce dentin permeability and to verify their resistance to erosive and abrasive challenges. Dentin disc specimens (1 mm thick) were treated with 0.5 M EDTA solution and randomly allocated into three experimental groups (n = 10): Control (Saliva); Concentrated Hybrid Coating (TEOS/GPTMS/Y-APS); and Diluted Hybrid Coating (1:3 ratio with distilled water). Dentin permeability was assessed by hydraulic conductance in the following experimental time periods: post-EDTA, post treatment, post erosion (5 min in 0.05 M citric acid solution, pH = 3.8), and post abrasion (toothbrushing for 3,900 cycles). Dentin permeability percent was calculated with respect the values of post-EDTA for each experimental time. The morphology of the surface of extra dentin specimens was examined by scanning electron microscopy (SEM) in the same time periods (n = 3). Permeability data were analyzed by two-way repeated measures ANOVA and Tukey tests (p < .05). Both HC presented significantly lower dentin permeability than control post treatment and post erosion (p < .05), without difference between them (p > .05). Post abrasion, there were no significant difference among groups (p > .05). Post treatment and post erosion, the HC seemed to flow into the tubules, occluding them, while the tubules in control remained opened. Post abrasion, the tubules appear to be occluded in all groups. In conclusion, the experimental hybrid coatings were capable of reducing dentin permeability after treatment. They were also able to resist to erosive and abrasive challenges, with the advantage of forming thinner and colorless films that can be potentially used to treat dentin hypersensitivity.

Dynamic Influence of pH on Metalloproteinase Activity in Human Coronal and Radicular Dentin.

The aim of this study was to evaluate the effect of pH on the activation of matrix metalloproteinases (MMPs) of human coronal (CD) and radicular dentin (RD). CD and RD were pulverized to powder, and proteins were extracted with 1% phosphoric acid. The extracted proteins and the demineralized powder were separately incubated in the following solutions: 4-aminophenylmercuric acetate (control) or a buffer solution at different pHs (2.5, 4.5, 5.0, 6.0, and 7.0). After incubation, proteins were separated by electrophoresis to measure MMP activities by zymography. To assess the solubilized dentin collagen, the demineralized dentin powder was sustained in incubation buffer, and the amount of hydroxyproline (HYP) released was measured. Zymography revealed MMP-2 gelatinolytic activities for CD and RD in all experimental groups. For both substrates, the lowest pH solutions (2.5, 4.5, and 5.0) yielded higher gelatinolytic activity than those obtained by the highest pH solutions (6.0 and 7.0). For HYP analysis, no detectable absorbance values were observed for pHs of 2.5 and 4.5. The amount of HYP was higher for pH 7.0 than those of all other groups (p < 0.05), except for pH 6.0. No statistical differences were found between pHs 6.0 and 5.0 and control (p > 0.05). The MMP-2 enzyme from human CD and RD is dynamically influenced by pH: at low pH, the extracted enzyme activates this latent form, whereas collagen degradation by the matrix-bound enzyme is only observed when pHs are close to neutral.

Effect of neodymium:yttrium-aluminum-garnet laser and fluoride on the acid demineralization of enamel.

AIM: The aim of the present study was to evaluate the protective effect of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser and acidic phosphate fluoride (APF) on enamel erosion caused by hydrochloric acid. METHODS: Fifty human enamel specimens were distributed according to the following treatments (n = 10): untreated (control), APF (1.23%) 4 min, Nd:YAG laser (100 mJ, 1 W, 10 Hz, 141.5 J/cm2 ), APF + Nd:YAG laser, and Nd:YAG laser + APF. For 14 days the specimens were submitted to erosive challenge: 5 min in 3 mL hydrochloric acid (0.01 M, pH 2.2), rinsed with distilled water, and stored in artificial saliva for 3 h. This cycle was repeated four times per day. The calcium (Ca) loss was determined in demineralizing solution by atomic emission spectroscopy, and superficial roughness (Ra) was measured before and after the erosive challenge. RESULTS: The mean Ca loss was (mg/L, ± standard deviation): control 12.74 ± 3.33, APF 1.71 ± 0.11, laser 1.64 ± 0.08, APF + laser 1.38 ± 0.08, and laser + APF 1.48 ± 0.07. Kruskal-Wallis test showed a significant difference between the control and other groups. APF + laser showed minor loss of Ca. After the erosive challenge, the APF + laser group showed Ra alteration. CONCLUSION: A significant reduction in tooth dissolution was observed after fluoride application combined with Nd:YAG irradiation.

Effect of the Mixture of Coffee or Chocolate to Milk in the Progression of Des-Remineralization of Tooth Enamel -An in Vitro Study

Objective:To evaluate if there is any interference when adding coffee or chocolate to cow milk in the enamel des-remineralization process (orange juice/saliva).Material and Methods:48 specimens of human enamel (4x4 mm) were included in acrylic resin, ground flat, polished and randomly divided into the following experimental groups (n = 8): G1-saliva, G2-orange juice, G3 orange juice / milk; G4-Orange Juice / Chocolate, G5-Orange Juice / Coffee + milk and G6-milk. Each group was immersed for 60 seconds on each solution proposed and then immersed for 30 minutes in saliva. This cycle was repeated 4 times. Prior to these cycles, the Knoop microhardness average of each specimen was obtained. After the challenges proposed, the final microhardness average was calculated. The values obtained from the difference between the initial and final microhardness were subjected to ANOVA followed by Tukey test (p <0,05).Results:The orange juice had the highest change in microhardness and statistically different from all other groups. The microhardness change was statistically similar in the groups submitted to orange juice followed by immersion in milk, in chocolate and in the mixture milk + coffee. The pure milk and saliva caused no change in surface hardness of enamel.Conclusion:Milk or the addition of chocolate and coffee to milk was able to produce aprotective effect of the enamel surface against an erosive challenge

Effect of mouthrinses with different active agents in the prevention of initial dental erosion.

INTRODUCTION: Hydrochloric acid (HCl) from the gastric juice is the only source of intrinsic acid, which can reach the oral cavity in cases of gastroesophageal reflux or chronic vomiting, enhancing the risk of dental erosion. AIM: Compare the effects of mouthrinses with different active agents in the prevention of initial dental erosion caused by HCl. SUBJECTS AND METHODS: Casein (CAS at 0.2%), sodium hexametaphosphate (HMP at 0.02%), titanium tetrafluoride (TiF4 at 0.34%), and stannous fluoride (SnF2 at 0.87%) were individually added to an experimental mouthrinse. The mouthrinse without additives was used as the negative control (C) and a commercially available mouthrinse for erosion (ELM-Elmex®) as the reference product. Enamel specimens were exposed to human saliva and randomly assigned to 6 experimental groups (n = 8). Specimens were submitted to erosion in HCl for 10 s, followed by to the experimental mouthrinses for 30 s, and artificial saliva for 60 min. This cycle was repeated 3 times. The total amounts of calcium and phosphorus released by the specimens in the 2nd and 3rd erosive challenges were evaluated by atomic emission spectrometry. Statistical analysis used Shapiro-Wilks and Hartley tests, followed by one-way ANOVA and Tukey tests. RESULTS: When compared with C, ELM and HMP presented significantly less calcium in solution, with no difference between them. All the groups showed similar and significantly less phosphorus than C, except CAS. CONCLUSIONS: HMP was the only agent that could match the protection against initial erosion of the commercially available mouthrinse in both analyses.

Supplementation of an orange juice with dietary proteins to prevent enamel and dentin erosion.

Protein supplementation may be an alternative to reduce the erosive potential of acidic drinks. The aim of this in vitro study was to evaluate the erosive potential of an orange juice modified by dietary proteins. A commercially available orange juice was added 0.2 g/L casein, 2.0 g/L ovalbumin and their combination. The juice with no additives and a commercially available calcium-modified juice were used as negative and positive controls, respectively. Human enamel and dentin specimens (n=11) were tested in an erosion-remineralization cycling model. Enamel was analyzed by surface microhardness and profilometry, whilst dentin by profilometry only. Statistical analyses were performed using one-way ANOVA followed by Tukey's test (p<0.05). Calcium-modified juice showed the lowest erosive potential for both analyses (p<0.05). For enamel, the protein-added groups did not differ from each other (p>0.05) and showed significantly lower enamel loss compared to negative control (p<0.05). Regarding surface microhardness, casein showed the highest values compared to negative control (p<0.05). For dentin, none of the protein-added groups showed lower values of surface loss compared to negative control (p>0.05). In conclusion, for enamel the protein-modified orange juices presented reduced erosion of enamel, with casein showing a trend for better protection. For dentin, no reduction in the erosive potential was observed for the tested protein-modified orange juices.

Choice of toothpaste for the elderly: an in vitro study.

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey's test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

Supplementation of an Orange Juice with Dietary Proteins to Prevent Enamel and Dentin Erosion

Protein supplementation may be an alternative to reduce the erosive potential of acidic drinks. The aim of this in vitro study was to evaluate the erosive potential of an orange juice modified by dietary proteins. A commercially available orange juice was added 0.2 g/L casein, 2.0 g/L ovalbumin and their combination. The juice with no additives and a commercially available calcium-modified juice were used as negative and positive controls, respectively. Human enamel and dentin specimens (n=11) were tested in an erosion-remineralization cycling model. Enamel was analyzed by surface microhardness and profilometry, whilst dentin by profilometry only. Statistical analyses were performed using one-way ANOVA followed by Tukey's test (p<0.05). Calcium-modified juice showed the lowest erosive potential for both analyses (p<0.05). For enamel, the protein-added groups did not differ from each other (p>0.05) and showed significantly lower enamel loss compared to negative control (p<0.05). Regarding surface microhardness, casein showed the highest values compared to negative control (p<0.05). For dentin, none of the protein-added groups showed lower values of surface loss compared to negative control (p>0.05). In conclusion, for enamel the protein-modified orange juices presented reduced erosion of enamel, with casein showing a trend for better protection. For dentin, no reduction in the erosive potential was observed for the tested protein-modified orange juices.

A suplementação de proteína pode ser uma alternativa na redução do potencial erosivo de bebidas ácidas. O objetivo deste estudo in vitro foi avaliar o potencial erosivo do suco de laranja modificado por proteínas da dieta. A um suco de laranja disponível comercialmente foi adicionado 0,2 g/L de caseína, 2,0 g/L de ovalbumina e suas combinações. O suco sem aditivos, e um suco suplementado com cálcio foram utilizados como controles negativos e positivos, respectivamente. Espécimes de esmalte humano e de dentina radicular (n=11) foram testados em um modelo de ciclagem de erosão-remineralização. O esmalte foi analisado por microdureza de superfície e perfilometria, enquanto que a dentina, apenas por perfilometria. As análises estatísticas foram realizadas utilizando ANOVA um fator seguido pelo Teste de Tukey (p<0.05). O suco suplementado com cálcio mostrou o menor potencial erosivo para ambas as análises (p<0,05). Em relação ao esmalte, os grupos com adição de proteína não diferiram entre si (p>0,05) e mostraram significativamente uma menor perda de esmalte em relação ao grupo controle negativo (p<0,05). Para a microdureza, a caseína apresentou os maiores valores em relação ao controle negativo (p<0,05). Para a dentina, nenhum dos grupos com adição de proteína apresentou valores de perda de superfície menores quando comparados ao grupo controle negativo (p>0,05). Conclui-se que, para o esmalte os sucos de laranja modificados por proteínas apresentaram uma redução da erosão, com a caseína mostrando uma tendência para melhor proteção. Para a dentina, nenhuma redução da erosão foi observada para os sucos de laranja modificados por proteínas testados neste estudo.

Choice of toothpaste for the elderly: an in vitro study

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey’s test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

Investigation of the prevalence, clinical features, and risk factors of dentin hypersensitivity in a selected Brazilian population.

OBJECTIVES: To evaluate the prevalence, clinical features, and risk factors of dentin hypersensitivity (DH) in a Brazilian population. MATERIALS AND METHODS: 300 patients at the Dentistry Clinic of the University of São Paulo participated in this study. The subjects completed a questionnaire regarding their personal information, the presence of DH, and some of its risk factors. Following completion of the questionnaire, a clinical examination was undertaken. To confirm the presence of DH, the subjects were evaluated with the use of a probe and cold air from a triple syringe. Statistical analysis was performed with the chi-square test and odds ratio, with the critical level p <0.05. RESULTS: The prevalence of DH was 46%. Females presented a higher prevalence than males (p <0.05). The left posterior region was affected by DH the most (maxilla = 41% and mandible = 36%). Cold was reported as the most common pain-inducing stimulus (88%). The pain was described as "discomfort" by 51% of the subjects with DH. Toothbrushing four times a day (p <0.05), toothbrushing with excessive force (p <0.05), bruxism (p <0.05), and gastroesophageal reflux (p <0.05) were strongly correlated with DH. CONCLUSIONS: The prevalence of DH was particularly high. The risk factors for DH were gender (female), toothbrushing four times a day, toothbrushing with excessive force, bruxism, and gastroesophageal reflux. CLINICAL RELEVANCE: DH was a common finding in this population suggesting that preventive measures considering its risk factors must be implemented in order to reduce or control the symptoms.

Lisura superficial de resinas compostas com nanopartículas após protocolos de acabamento e polimento / Smooth surface of nanoparticle composites after finishing and polishing protocols

O objetivo desse estudo foi avaliar a lisura de superfície de três resinas compostas por nanopartículas, após serem submetidas a três diferentes sistemas de acabamento e polimento. Foram obtidos 40 corpos de prova de cada resina (Filtek Z350 XT, Premise e Charisma Diamond) e distribuídos em quatro grupos experimentais (n=10): C (controle) - sem tratamento; SOF -Discos abrasivos Soflex; ENH - Pontas siliconadas Enhance e F/FF - Pontas diamantadas de granulação fina/extra-fina + disco de feltro e pasta diamantada. Após 24h da confecção e armazenamento, os sistemas de acabamento e polimento foram aplicados. A lisura superficial foi avaliada utilizando-se um rugosímetro, tendo sido realizadas cinco leituras em cada corpo de prova. A média dos valores de rugosidade de superfície [um] obtidos foi analisada através da ANOVA, dois fatores, seguido do teste de Tukey, com significância de 1%. Para todas as resinas testadas, houve diferença estatística entre os sistemas de acabamento e polimento testados (p<0,01). Para a resina Charisma, os valores de rugosidade foram: C - 0,10a; SOF - 0,24b; ENH - 0,23b; F/ FF - 0,32c. Para a Premisa: C-0,12a; SOF - 0,16ab; ENH - 0,22b; F/FF - 0,30<. Para a Filtek: C - 0,08'; SOF - 0,14ab; ENH - 0,20b<; F/FF - 0,26<. No grupo controle foram obtidos os melhores resultados de lisura de superfície para todas as resinas testadas. Em relação aos tratamentos, os grupos SOF e ENH promoveram as melhores lisuras de superfície, enquanto que o grupo F/FF resultou em superfícies com maiores rugosidades.

The aim of this study was to evaluate the smoothness surface of 3 composites by nanoparticles (Filtek Z350 XT, Premise e Charisma Diarnond], after being subjected to three different finishing and polishing systems. Were obtained 40 specimens of each resin selected and randomly divided into 4 experimental groups (n= 10): C (control) - no treatment; SOF - Abrasive discs Soflex; ENH - silicon tips Enhance; and F / FF - diamond tips fine/extra-fine granulation + felt disc and diamond paste. Twenty-four hours after the preparation and storage of the specimens in distilled water at 37°(, the finishing and polishing systems were applied. The smooth surface of the composites was evaluated using a rugosimeter, where five readings were taken on each specimen. The mean surface roughness (um) were analyzed by ANOVA, two factors, followed by Tukev's test, with significance of 1%. For ali resins tested, statistical difference was found between finishing and polishing systems tested (p<0,01). To the resin Charisma roughness values were: C - 0,10a; SOF - 0,24b; ENH - 0,23b; F/ FF - 0,32c. For the premise : C-0,12a; SOF - 0,16ab; ENH - 0,22b; F/FF - 0,30<. Para a Filtek: C - 0,08'; SOF - 0,14ab; ENH - 0,20b<; F/FF - 0,26<. The control group obtained better results of surface smoothness for ali composites tested. Regarding the treatments groups, SOF and ENH resulted on better smoothness surface, while the group FI FF resulted in surfaces with higher roughness.

The effect of milk ingestion after an orange juice in the superficial microhardness of human enamel: an in vitro study

Patients diet and habits are important factors that can determine the ocurrence of dental erosion. The objective of this study was to evaluate the ability of milk to reduce the erosion caused by orange juice in enamel. Specimens of human teeth were mbeddedd in acrylic resin, polished and submitted to the initial microhardness measurement (SMH) using a Knoop indenter with 25 g load for 10 seconds. The specimens with similar values of SMH were randomly divided into 4 experimental groups (n=10) according to the following treatments: C (Control): 30 minutes of immersion in artificial saliva; OJ: 1 minute of immersion in orange juice, followed by 30 minutes in artificial saliva; M: 1 minute of immersion in cow's milk followes by 30 minutes in artificial saliva; OJ + M: 1 minute of immersion in orange juice follwed by 1 minute in milk and 30 minutes of artificial saliva. These treatments were repeated for four times.The final SMH was determined and means of SMH values were calculated. Data were analyzed using ANOVA and Tukey's Test (p menor do que 0.05). The immerison of the specimens in milk after orange juice was able to reduce the surface softening caused by this acidic drink. It was concluded that milk after an erosive challenge may be an alternative to reduce enamel surface softening.

A ausência de radiopacidade em algunscimentos de ionômero de vidro / The absence of radiopacity of some glass ionomer cements

A radiopacidade é um pré-requisito imprescindível para materiais utilizados como base eforramento de restaurações. Possibilita que o profissional identifique a presença do material,permitindo a diferenciação com a estrutura dental adjacente. Objetivo: O objetivo desse estudofoi avaliar a radiopacidade de materiais de base e forramento disponíveis para uso clínico ecomparar com a radiopacidade do esmalte e dentina. Materiais e Métodos: Foram analisados:13 marcas comerciais de cimento de ionômero de vidro, 1 amálgama e 1 resina composta. Foramconfeccionados três corpos de prova com espessura de 1 mm para cada cimento de ionômerode vidro e para cada material restaurador. Obteve-se 1 espécime, com 1 mm de espessura, deesmalte/dentina através de um corte transversal da coroa dental. As tomadas radiográficas foramfeitas com o sistema digital ~VG 5000 Kodak e tempo de exposição de 0,32 segundos. Asimagens obtidas foram trabalhadas no programa Image Tool® obtendo-se os valores médiosde cinza. A análise estatística ANOVA, seguida pelo teste de Tukey (p 0,05) detectou diferençasconsideráveis. Resultados: Alguns cimentos de ionômero de vidro apresentaram radiopacidadeinferior à da dentina e inadequada segundo as normas ISO9917, sendo considerada insuficientepara um correto diagnóstico radiográfico. Conclusão: Conclui-se que existem cimentos de ionômerode vidro indicados como base e forramento de restaurações disponíveis para aquisiçãocom radiopacidade imprópria para serem detectados radiograficamente.

The radiopacity is an essential prerequisite for materiais used as a base liner and restorationsand allows the professional to identify the presence of the material allowing the differentiationfrom the adjacent tooth structure. Objectives: The aim of this study was to evaluate the radiopacityof base and liner materiais available for clinical use and compare to the radiopacity ofenamel and dentin. Materiais and methods: 13 glass ionomer cements, one resin composite andone amalgam were evaluated. Three specimens with 1 mm thickeness for each glass ionomercement and restorative material were prepared. Cross section was made from a third molardental crown to obtain enamel and dentin specimen with thickness of 1 mm. Radiographswere taken with digital system Kodak RVG5000 and exposure time of 0.32 seconds. The imageswere analysed through the programe Image Tool" to obtain the mean grey values. Statisticaltest ANOVA followed by Tukey test (p<0.05) detected considerable differences. Results: Someglass ionomer cements presented radiopacity lower than dentin, considered insufficient for acorrect radiographic diagnosis, according to ISO 9917. Conclusion: It was concluded that somebase and liner materiais available for purchase have an inadequaderadiopacity to be detectedradiographically.

Interaction between staining and degradation of a composite resin in contact with colored foods.

Composite resins might be susceptible to degradation and staining when in contact with some foods and drinks. This study evaluated color alteration and changes in microhardness of a microhybrid composite after immersion in different colored foods and determined whether there was a correlation between these two variables. Eighty composite disks were randomly divided into 8 experimental groups (n = 10): kept dry; deionized water; orange juice; passion fruit juice; grape juice; ketchup; mustard and soy sauce. The disks were individually immersed in their respective test substance at 37 ºC, for a period of 28 days. Superficial analysis of the disk specimens was performed by taking microhardness measurements (Vickers, 50 g load for 45 seconds) and color alterations were determined with a spectrophotometer (CINTRA 10- using a CIEL*a*b* system, 400-700 nm wavelength, illuminant d65 and standard observer of 2º) at the following times: baseline (before immersion), 1, 7, 14, 21 and 28 days. Results were analyzed by ANOVA and Tukey's test (p < 0.05). Both variables were also submitted to Pearson's correlation test (p < 0.05). The passion fruit group underwent the greatest microhardness change, while the mustard group suffered the greatest color alteration. Significant positive correlation was found between the two variables for the groups deionized water, grape juice, soy sauce and ketchup. Not all color alteration could be associated with surface degradation.

Interaction between staining and degradation of a composite resin in contact with colored foods

Composite resins might be susceptible to degradation and staining when in contact with some foods and drinks. This study evaluated color alteration and changes in microhardness of a microhybrid composite after immersion in different colored foods and determined whether there was a correlation between these two variables. Eighty composite disks were randomly divided into 8 experimental groups (n = 10): kept dry; deionized water; orange juice; passion fruit juice; grape juice; ketchup; mustard and soy sauce. The disks were individually immersed in their respective test substance at 37 ºC, for a period of 28 days. Superficial analysis of the disk specimens was performed by taking microhardness measurements (Vickers, 50 g load for 45 seconds) and color alterations were determined with a spectrophotometer (CINTRA 10- using a CIEL*a*b* system, 400-700 nm wavelength, illuminant d65 and standard observer of 2º) at the following times: baseline (before immersion), 1, 7, 14, 21 and 28 days. Results were analyzed by ANOVA and Tukey's test (p < 0.05). Both variables were also submitted to Pearson's correlation test (p < 0.05). The passion fruit group underwent the greatest microhardness change, while the mustard group suffered the greatest color alteration. Significant positive correlation was found between the two variables for the groups deionized water, grape juice, soy sauce and ketchup. Not all color alteration could be associated with surface degradation.

Abrasion resistance of different resin composites / Resistência à abrasão de diferentes resinas compostas

Objective - This study evaluated the influence of toothbrushing and thermal cycling on surface roughness and weight alterations of four different composite resins. Methods - Five specimens of two nanofilled composites (Filtek Supreme and Esthet X), one submicron composite(spherical filler) (Palfique Estelite) and one microhybrid composite (irregular filler) (Filtek Z250/3M ESPE), were prepared according to the manufacturer's directions. Each specimen was thermal cycled 1,200 times and subjected to 40,000 toothbrushing cycles. At baseline and after thermal cycling and tootbrushing cycles, surface roughness and weight were determined. Results - After thermal cycling and toothbrush abrasion no statistically significant difference in weight was found, however, the Esthet X and Palfique Estelite showed decrease in weight while Filtek Supreme and Z250 showed increase in weight. The surface roughness increased after thermal cycling and toothbrushing (p<0.01). The spherical submicron filler (Palfique Estelite) showed the smoothest surface. Conclusion - According to the methodology applied in this study, all resins studied showed resistance to abrasion, however, Palfique Estelite after the tests showed the smoothest surface.

Objetivo - Este estudo avaliou a influência da escovação e alterações térmicas quanto às alterações superficiais de rugosidade e peso de quatro diferentes resinas compostas. Métodos - Foram empregadas duas resinas de nanopartículas (Filtek Supreme e Esthet X), uma microparticulada de partículas esféricas (Palfique Estelite) e uma microhíbrida de partículas irregulares (Filtek Z250). Foram preparados cinco corpos de prova para cada material de acordo com as instruções do fabricante. Cada corpo de prova foi ciclado 1.200 vezes e submetido a 40.000 ciclos de escovação. O peso e rugosidade da superfície foram determinados antes e após os ciclos térmicos e de escovação. Resultados - Esthet X e Palfique Estelite mostraram diminuição do peso enquanto que Filtek Supreme e Z250 apresentaram aumento, no entanto, não houve diferença estatisticamente significativa após ciclagem térmica e de escovação. A rugosidade superficial aumentou em todas as resinas compostas testadas após a ciclagem térmica e de escovação, sendo que a resina microparticulada de partículas esféricas (Palfique Estelite) apresentou ao final dos testes a superfície mais lisa (p<0.01). Conclusão - De acordo com a metodologia aplicada nesta pesquisa, todas as resinas compostas estudadas apresentaram resistência à abrasão, no entanto, a Palfique Estelite apresentou ao final dos testes a maior lisura superficial.

The effect of fluoride therapies on the morphology of bleached human dental enamel.

The aim of this in vitro study was to evaluate qualitatively the surface morphology of enamel bleached with 35% hydrogen peroxide (HP) followed by application of fluoridated agents. Forty intact pre molars were randomly distributed into four groups (n = 10), treated as follows: Group I (control group) remained stored in artificial saliva at 37 °C, Group II - 35% HP; Group III - 35% HP + acidulated fluoride (1.23%) and Group IV - 35% HP + neutral fluoride (2%). The experimental groups received three applications of bleaching gel and after the last application all specimens were polished. This procedure was repeated after 7 and 14 days, and during the intervals of applications, the specimens were stored in artificial saliva at 37°C. Scanning electron microscopy (SEM) analysis showed superficial irregularities and porosities to varying degrees in bleached enamel compared to control group. Sample evaluation was made by attributing scores, and data were statistically analyzed using Kruskal-Wallis and Dunn tests (P < 0.05). SEM qualitative investigation demonstrated that 35% hydrogen peroxide affected human dental enamel morphology, producing porosities, depressions, and superficial irregularities at various degrees. These morphological changes were higher after the application of 1.23% acidulated fluoride gel.