Chitosan improves the durability of resin-dentin interface with etch-and-rinse or self-etch adhesive systems

Degradation of the dentin-resin interface can occur due to hydrolysis of exposed collagen, resulting in reduced bond strength. This study assessed the effect of dentin treatment with chitosan combined with an etch-and-rinse or self-etch adhesive system on improvement of bond strength and preservation of the interface durability. Methodology: Enamel was removed from 80 molars and the teeth were divided into two groups: without chitosan (control) or with 2.5% chitosan gel (1 min). They were further subdivided into two subgroups according to the adhesive system: etch-and-rinse or self-etch. Dentin was restored using a composite resin. Half of the specimens from each restored group were subjected to interface aging and the remaining specimens were used for immediate analysis. The specimens were sectioned and subjected to microtensile bond strength (µTBS) test (n=10), chemical composition testing using Fourier-transform infrared (FTIR) spectroscopy (n=4) and energy-dispersive spectroscopy (EDS) (n=5), and morphological analysis of the adhesive interface using scanning electron microscopy (SEM) (n=5). Data were analyzed using three-way ANOVA. Results: Chitosan improved the µTBS of the adhesive interface when compared with the control group (p=0.004). No significant differences were observed in dentin adhesion between the adhesive systems (p=0.652). Immediate µTBS was not significantly different from that after 6 months (p=0.274). EDS and SEM did not show significant differences in the chemical and structural composition of the specimens. FTIR showed a decrease in the intensity of phosphate and carbonate bands after using chitosan. Conclusions: Dentin treatment with chitosan combined with an etch-and-rinse or self-etch adhesive system improved the immediate and preserved the 6-month bond strength of the adhesive interface

The Impact of CO2 Laser Treatment and Acidulated Phosphate Fluoride on Enamel Demineralization and Biofilm Formation

Introduction: This study evaluated the impact of CO2 laser treatment and acidulated phosphate fluoride (APF) on enamel demineralization and biofilm formation, using in vitro and in situ designs.Methods: Demineralized enamel slabs were distributed among 8 groups: placebo, placebo + continuous CO2 laser, placebo + repeated CO2 laser, placebo + ultrapulsed CO2 laser, 1.23% APF, APF + continuous CO2 laser, APF + repeated CO2 laser and APF + ultrapulsed CO2 laser. In the in vitro study, 15 enamel slabs from each group were subjected to a pH-cycling regimen for 14 days. In the cross over in situ design, 11 volunteers wore palatal appliances with demineralized enamel slabs for 2 periods of 14 days each. Drops of sucrose solution were dripped onto enamel slabs 8×/day. Biofilms formed on slabs were collected and the colony-forming units (CFU) of Streptococcus mutans and Lactobacillus were determined. Results: For both in vitro and in situ studies, there was no significant difference between treatments (P > 0.05). However, all treatments increased microhardness of demineralized enamel (P < 0.05). After a further in situ cariogenic challenge, with the exception of the placebo, all treatments maintained microhardness values (P < 0.05). Microbiological analysis showed no difference in Streptococcus mutans (P > 0.05) or Lactobacillus (P > 0.05) counts between groups. Conclusion: The results suggest that APF gel combined with the CO2 laser, regardless of the pulse emission mode used, was effective in controlling enamel demineralization, but none of the tested treatments was able to prevent bacterial colonization

Selective Removal of Necrotic Dentin in Primary Teeth Using Laser Irradiation: One-Year Clinical Evaluation of Composite Restorations

Introduction: This study aimed to evaluate the child’s salivary cortisol levels, clinical performance and marginal adaptation of restorations after selective removal of necrotic dentin in primary teeth using Er: YAG laser irradiation.Methods: A double-blind clinical study was performed in children at 7-10 years. Children who had at least 2 teeth with carious lesions involving the occlusal and proximal surfaces of primary molars counterparts were selected. Removal of necrotic dentin was performed by 2 methods: Er: YAG laser irradiation and bur-preparation. Cortisol levels (n = 24) was evaluated by ELISA. Clinical analysis (n = 20) was performed after the restorations polish, 6 and 12 months after restorative procedure using United States Public Health Service (USPHS) method and photographs. Scanning electron microscopy (SEM) was used to analyz the marginal gap formation (n = 20). The analysis of the data was performed by 95% confidence interval, Shapiro-Wilk test, Friedman and Wilcoxon post hoc tests (α = 5%).Results: Cortisol levels were higher during selective removal of necrotic dentin, regardless of the method used (P > 0.05). After 12 months, there was no evidence of the difference in the restorations performed on cavities prepared by both methods. SEM analysis revealed that the laser-irradiated teeth showed 10% of gaps in the full extent of restoration. For bur-prepared teeth, 20% of gaps were found at the cavosurface margin.Conclusion: The salivary cortisol levels on children that received Er: YAG laser irradiation for removal the necrotic dentin was similar to the control group. Class II restorations evaluated after 1 year period did not suffer interference by the use of Er: YAG laser irradiation

Self-perception of the need for full dental prosthesisamong toothless elderly Brazilians

Propõe-se estimar a prevalência da autopercepção da necessidade de prótese dentária total entre idosos (65 a 74 anos) brasileiros desdentados, assim como identificar seus fatores associados. Trata-se de estudo transversal com base no inquérito nacional das condições de Saúde Bucal da população brasileira, denominado SB Brasil – 2010. A variável dependente foi a autopercepção da necessidade de prótese dentária total, considerando a aquisição de prótese nova ou substituição da existente. Foram conduzidas análises descritivas, bivariadas e múltiplas. Foram incluídos 3514 idosos, destes, 2039 (55,0%) perceberam a necessidade de prótese total. A autopercepção da necessidade de prótese total foi maior entre os que necessitavam de prótese dentária inferior e que estavam insatisfeitos com as suas condições de saúde bucal. Além da alta prevalência da autopercepção da necessidade de prótese identificada, os resultados permitiram identificar que condições normativas e subjetivas de saúde bucal se mantiveram associadas a esta autopercepção entre idosos brasileiros.211134073415The objective is to estimate the prevalence of self-perception of the need for a full dental prosthesis among toothless elderly Brazilians aged 65 to 74, as well as identify the associated factors. It is a cross-sectional study based on the national survey of oral health conditions of the Brazilian population, called SB Brazil – 2010. The dependent variable was the self-perceived need for full dental prosthesis, considering the purchase of new or replacement of the existing prosthesis. Descriptive bivariate and multiple analyses were conducted on 3514 elderly people, of which 2039 (55%) elderly self-perceived the need for a full denture. The self-perception of the need for a full denture was higher among those who needed dental prosthesis and who were dissatisfied with their oral health conditions. In addition to the high prevalence of self-perception of the need for prosthesis identified, the results identified that normative and subjective conditions of oral health remained associated with this self-perception among elderly Brazilians

A list of land plants of Parque Nacional do Caparaó, Brazil, highlights the presence of sampling gaps within this protected area

Brazilian protected areas are essential for plant conservation in the Atlantic Forest domain, one of the 36 global biodiversity hotspots. A major challenge for improving conservation actions is to know the plant richness, protected by these areas. Online databases offer an accessible way to build plant species lists and to provide relevant information about biodiversity. A list of land plants of “Parque Nacional do Caparaó” (PNC) was previously built using online databases and published on the website "Catálogo de Plantas das Unidades de Conservação do Brasil." Here, we provide and discuss additional information about plant species richness, endemism and conservation in the PNC that could not be included in the List. We documented 1,791 species of land plants as occurring in PNC, of which 63 are cited as threatened (CR, EN or VU) by the Brazilian National Red List, seven as data deficient (DD) and five as priorities for conservation. Fifity-one species were possible new ocurrences for ES and MG states

Progression of caries-like lesions following CO2 laser irradiation or fluoride sources in human and bovine enamel.

A presente tese foi dividida em 2 estudos cujos objetivos específicos foram: 1) Comparar in vitro o efeito da irradiação do laser de CO2 a compostos fluoretados na inibição da progressão de lesões de cárie, e testar se o padrão de resposta é similar ao esmalte humano e bovino. 2) Avaliar in situ a progressão da lesão de cárie no esmalte bovino e verificar as quantidades de flúor no biofilme e no esmalte após tratamento com verniz fluoretado associado ou não ao laser de CO2. No primeiro estudo, 96 fragmentos de esmalte (48 humanos e 48 bovinos) foram distribuídos aleatoriamente em 4 grupos (n=12): CO2 - laser de CO2 (10,6 µm), VF - verniz fluoretado a 5%, FFA - flúor fosfato acidulado a 1,23% e ST - sem tratamento. Os espécimes foram submetidos a 14 dias de desafio cariogênico (ciclagem de pH). A microdureza (KHN) foi medida a 30 µm da superfície. Vinte fragmentos adicionais de cada substrato receberam os mesmos tratamentos (n=5) e foram analisados em microscopia eletrônica de varredura (MEV).No estudo in situ (cruzado e realizado em 2 fases de 14 dias cada), 14 voluntários (n=14) utilizaram um dispositivo palatino contendo blocos de esmalte bovino que foram previamente submetidos a um dos 4 tratamentos: VF + CO2 - verniz Fluoretado a 5% + laser de CO2, VF- verniz fluoretado a 5%, VP - verniz placebo sem flúor, VP + CO2 - verniz placebo + laser de CO2. Biofilme dental foi acumulado sobre os blocos e 6 vezes ao dia os voluntários gotejavam solução de sacarose, simulando um desafio cariogênico. Após cada fase, os blocos foram removidos para avaliação da desmineralização do esmalte (teste de microdureza) e concentração de fluoreto no biofilme e esmalte após o desafio cariogênico. A microdureza foi avaliada pela Análise de Variância e teste de Tukey e as dosagens de flúor no biofilme e esmalte pelo teste não paramétrico de Friedman (α = 5%). No estudo in vitro, verificou-se que o laser de CO2 promoveu a menor perda mineral, seguido do tratamento com VF e FFA, o desempenho inferior na inibição da progressão de cárie foi obtido com o grupo controle (ST) (p VF > FFA > ST. O dente bovino apresentou maiores valores de microdureza que o humano, embora o comportamento dos substratos tenha sido o mesmo para todos os tratamentos. A MEV demonstrou presença de fino precipitado granuloso para o grupo VF e fusão e fissuras para o grupo tratado com CO2. No estudo in situ, independentemente da aplicação dos vernizes fluoretado ou placebo, a microdureza do esmalte foi estatisticamente superior (p 0,05) na microdureza do esmalte bovino em função do uso do produto fluoretado e placebo. Ao analisar o biofilme dental, observou-se que o grupo tratado com VF apresentou maior quantidade de flúor, estatisticamente diferente dos demais grupos (p 0,05). No esmalte, a maior quantidade de flúor foi encontrada no grupo VF + CO2 (p 0,05). Conclui-se que: 1) O laser de CO2 controlou a progressão de cárie in vitro mais eficazmente que compostos fluoretados de alta concentração e, que o esmalte bovino pode ser um substituto ao esmalte humano em estudos desta natureza; 2) O laser de CO2 promoveu maior inibição da progressão de cárie, em modelo in situ, independentemente da aplicação dos vernizes fluoretado ou placebo. O uso do verniz fluoretado resultou em maior quantidade de flúor no biofilme dental, enquanto que, a associação verniz fluoretado e laser de CO2 proporcionou maior incorporação de flúor no esmalte.This thesis was divided into 2 studies whose specific objectives were: 1) To compare the ability of CO2 laser and fluoride sources to inhibit caries-like lesions in human enamel and to test whether a similar pattern of response would hold for bovine enamel. 2) Evaluate in situ the progression of caries lesions in bovine enamel and to verify the amount of fluoride present in biofilm and enamel after treatment with fluoride varnish combined with CO2 laser. In the first study, 96 enamel slabs (48 from bovine and 48 from human teeth) were randomly distributed into 4 groups (n=12): CO2 - CO2 laser, FV - 5% fluoride varnish, APF - 1.23% acidulated phosphate fluoride gel, or WT - without treatment (control). Specimens were subjected to a 14-day in vitro cariogenic challenge. Microhardness (SMH) was measured at 30 µm from the surface. Additional 20 slabs of each substrate (n=5) received the same treatment described above and were analyzed by scanning electron microscopy (SEM). In the in situ study (crossover and performed in 2 phases of 14 days each), 14 (n = 14) wore palatal appliance with bovine enamel blocks that were previously submitted to one of the 4 treatments: FV + CO2 - 5% fluoride varnish + CO2 laser, FV - fluoride varnish, PV - placebo varnish without fluoride, PV + CO2 - placebo varnish + CO2 laser. Dental biofilm was allowed to accumulate on the blocks and 6 times a day a drop of sacarose solution was dispensed into emamel blocks by volunteers, simulating a cariogenic challenge. After each phase, the blocks were removed to evaluate enamel demineralization (microhardness test) and concentration of fluoride in biofilm and enamel after cariogenic challenge. Microhardness was evaluated by ANOVA and Tukey test, and the amount of fluoride present in biofilm and enamel were analysed by non-parametric Friedman test (α = 5%). CO2 laser promoted the least mineral loss. Treatment with FV resulted in the second highest values, which was followed by APF. Untreated specimens performed the worst (p FV > APF > WT. Bovine teeth presents higher values of microhardness than human, although the performance of both substrates were the same. SEM showed a granulate precipitate on FV group and fusion ang fissures on lased-specimens. In in situ study, regardless of the application of fluoride or placebo varnish, the microhardness of enamel was statistically superior (p 0.05). When analyzing the dental biofilme, it was observed that the group treated with VF presented larger amount of fluoride, statistically different from the other groups (p 0.05). In the enamel, the largest amount of fluoride was found in the FV + CO2 group (p 0.05). It was concluded that: 1) CO2 laser may control caries progression more efficiently than fluoride sources and bovine teeth may be a suitable substitute for human teeth in studies of this nature; 2) CO2 laser promoted larger inhibition of the caries progression, in in situ model, independently of the application of fluoride or placebo varnish. The use of fluoride varnish fluoretado resulted in larger amount of fluoride in dental biofilme, while, the association of fluoride varnish and CO2 laser provided larger fluoride uptake in the enamel

Impact of hydrogen peroxide activated by lighting-emitting diode/laser system on enamel color and microhardness: An in situ design

Background: Hydrogen peroxide (HP) at lower concentration can provide less alteration on enamel surface and when combined with laser therapy, could decrease tooth sensitivity. This in situ study evaluated the influence of 15% and 35% HP gel activated by lighting-emitting diode (LED)/laser light for in-office tooth bleaching. Materials and Methods: Forty-four bovine enamel slabs were polished and subjected to surface microhardness (load of 25 g for 5 s). The specimens were placed in intraoral palatal devices of 11 volunteers (n = 11). Sample was randomly distributed into four groups according to the bleaching protocol: 15% HP, 15% HP activated by LED/laser, 35% HP, and 35% HP activated by LED/laser. The experimental phase comprised 15 days and bleaching protocols were performed on the 2 nd and 9 th days. Surface microhardness (KHN) and color changes were measured and data were analyzed by ANOVA (α = 0.05). Results: There were no significant differences in microhardness values neither in color alteration of enamel treated with 15% HP and 35% HP activated or not by LED/laser system (P > 0.05). Conclusions: Both concentrations of HP (15 or 35%), regardless of activated by an LED/laser light, did not affect the surface microhardness and had the same effectiveness in enamel bleaching

Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis

Abstract The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT). Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26) and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each). Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm3) in the apical region was analyzed using the two-way ANOVA and post-hoc Student–Newman–Keuls test (α = ٠.٠٥). The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009) and Endofill (0.103 ± 0.010). The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008) and Sealer 26 (0.109 ± 0.018) (p > 0.05). Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012) (p < 0.05). Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique