Experimental resin-based dual-cured calcium aluminate and calcium titanate materials for vital pulp therapy

Abstract: This paper evaluates the physicochemical and biological properties of experimental resin-based dual-cured calcium aluminate (CA) and calcium titanate (CTi) materials for vital pulp therapy (VPT). The experimental dual-cured materials were obtained as two pastes: a) Bis-EMA 10, PEG 400, DHEPT, EDAB, camphorquinone, and butylated hydroxytoluene; and b) fluoride ytterbium, Bis-EMA 10, Bis-EMA 30, benzoyl peroxide, and butylated hydroxytoluene. The materials were divided into six groups based on the added calcium component: MTA (MTA®, Angelus); CLQ (Clinker-Fillapex®, Angelus); CA (calcined at ,1200°C in pastes a and b); CA800 (calcined at 800°C in paste a); CA1200 (calcined at 1,200°C in paste a); and CTi (paste a). The real-time degree of conversion and rate of polymerization (n = 3), diametral tensile strength (n = 10), hydrogen potential (n = 15), calcium ion release (n = 10), water sorption and solubility (n = 10), and cell viability (n = 6) were evaluated. One- and two-way ANOVA and Tukey's post hoc test were used in the analysis of the parametric data, and Kruskal-Wallis and Dunn's multiple tests were used to analyze the nonparametric data (α = 0.05). CLQ, CA800 and CA1200 had the highest diametral tensile strength. The water solubility of MTA was similar to that of CA800, CA1200 and CTi. CA800 and CA1200 resulted in cell viabilities similar to those of MTA and CLQ. The experimental dual-cured CA-based material that calcined at 800°C showed physicochemical and biological properties suitable for VPT, and similar to those of MTA.

Effect of alpha-humulene incorporation on the properties of experimental light-cured periodontal dressings

Abstract The objective of this study was to formulate an experimental light-cured periodontal dressing containing alpha-humulene and to compare its physical, antimicrobial, and cytotoxicity properties with commercial gold standards (Barricaid® and Periobond®). Two periodontal dressing formulations were developed (a and b). The formulations were divided into 5 groups according to the alpha-humulene concentration as follows: Ea - control group, Ea1 - 1%, Ea5 - 5%, Ea10 - 10%, and Ea20 - 20%; Eb - control group, Eb1 - 1%, Eb5 - 5%, Eb10 - 10%, and Eb20 - 20%. Materials characterization was performed using the degree of conversion, cohesive strength, sorption, and solubility assays. Antimicrobial assay was performed using the modified direct contact test against E. faecalis and S. aureus. Cytotoxicity was assessed by the cell viability experiment using L929 fibroblasts. In general, the cohesive strength values of materials decreased as the alpha-humulene concentration increased. All the experimental dressings showed antimicrobial activity against both bacteria tested. Cell viability results for the Ea, Ea1, Eb, and Eb1 groups showed moderate cytotoxic effect. The formulations containing alpha-humulene showed similar behavior to the commercial references. Thus, formulations containing alpha-humulene have potential to be used as periodontal dressing.

Evaluation of physical and biological properties of conventional glass ionomer cements / Avaliação das propriedades físicas e biológicas de cimentos de ionômero de vidro convencionais

Objetivo: avaliar as propriedades físicas e biológicas dos cimentos de ionômero de vidro convencionais (CIVs). Metodologia: foram avaliados os seguintes CIVs: Fuji IX (GC Europe, Bélgica), Ketac Molar (3M ESPE, Estados Unidos), Maxxion R (FGM, Brasil) e Vitro Molar (Nova DFL, Brasil). O tempo de presa, a alteração dimensional, a radiopacidade, a sorção e a solubilidade em água foram avaliados para todos os materiais. A resistência à compressão foi analisada em intervalos de 1h, 24h, 7 dias e 28 dias; e liberação de íons fluoreto em 3h, 24h e 72h. A viabilidade celular foi avaliada após 24 e 48 horas com células de fibroblastos. A análise estatística foi realizada por meio do software SigmaPlot 12 (Systat Inc, San Jose, CA, EUA), com nível de significância estabelecido em α = 0,05. Resultado: apenas o Fuji IX teve um tempo de presa dentro da faixa recomendada pela Especificação Padrão da ADA 96 (2012), não superior a 6 minutos. Vitro Molar e Maxxion R apresentaram radiopacidade que não estava de acordo com a especificação ADA 96 (2012). Maxxion R e Vitro Molar mostraram uma alteração dimensional estatisticamente semelhante. Quanto às propriedades mecânicas, o Fuji IX foi o único CIV que apresentou aumento da resistência à compressão durante o período de avaliação de 28 dias. O Ketac Molar apresentou a maior viabilidade celular, enquanto o Maxxion R apresentou citotoxicidade severa e o maior valor cumulativo de liberação de flúor. Conclusão: Fuji IX e Ketac Molar apresentaram as propriedades físicas e biológicas mais adequadas entre os CIVs avaliados.(AU)

Objective: to evaluate the physical and biological properties of conventional glass ionomer cements (GICs). Methodology: the following GICs were evaluated: Fuji IX (GC Europe, Belgium), Ketac Molar (3M ESPE, United States), Maxxion R (FGM, Brazil) and Vitro Molar (Nova DFL, Brazil). Setting time, dimensional change, radiopacity, water solubility and water absorption were evaluated for all materials. Compressive strength was analyzed after intervals of 1h, 24h, 7 days and 28 days; and release of fluoride ions at 3 am, 24 am and 72 am. Cell viability was assessed after 24 and 48 hours with fibroblast cells. Statistical analysis was performed using SigmaPlot 12 software (Systat Inc, San Jose, CA, USA), with a significance level set at α = 0.05. Result: only the Fuji IX had an adjustment time within the range recommended by the Standard Specification of ADA 96 (2012) of not exceeding 6 minutes. Vitro Molar and Maxxion R had radiopacity that was not in accordance with the ADA 96 (2012) specification. Maxxion R and Vitro Molar showed a statistically similar dimensional change. As for mechanical properties, Fuji IX was the only GIC that showed an increase in compressive strength during the evaluation period of 28 days. Ketac Molar showed the highest cell viability, while Maxxion R showed severe cytotoxicity and the highest cumulative fluoride release value. Conclusion: Fuji IX and Ketac Molar showed the most appropriate physical and biological properties among the evaluated GICs.(AU)

Evaluation of dentin hypersensitivity treatment with glass ionomer cements: A randomized clinical trial

Abstract A randomized, double-blind, split-mouth clinical trial was performed compared the desensitizing efficacy of the resin-modified glass ionomer cement (GIC) ClinproTM XT (3M ESPE, Minnesota, USA) and the conventional GIC Vidrion R (SS White, Gloucester, UK) in a 6-month follow-up. Subjects were required to have at least two teeth with dentin hypersensitivity. Teeth were divided at random into 2 groups, one group received Clinpro XT and the other conventional GIC Vidrion R. Treatments were assessed by tactile and air blast tests using Visual Analogue Scale (VAS) at baseline, after 20 minutes, and at 7, 15, 21, 30, 90 and 180 days post-treatment. Twenty subjects (152 teeth) were included. Both tests (tactile and air blast) showed a significant reduction of dentin hypersensitivity immediately after the application of Vidrion R and Clinpro XT (20 min). VAS scores obtained along the 6-month follow-up were statistically lower when compared to initial rates (p < 0.05). Both GIC were able to reduce dentin hypersensitivity up to 6-month post-treatment period without statistically significant differences among them (p > 0.05). Both cements provided satisfactory results in long-term dental sensitivity reduction.

Fifty years of Brazilian Dental Materials Group: scientific contributions of dental materials field evaluated by systematic review

ABSTRACT Objective A systematic review was conducted to analyze Brazilian scientific and technological production related to the dental materials field over the past 50 years. Material and Methods This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (Prisma) statement. Searches were performed until December 2014 in six databases: MedLine (PubMed), Scopus, LILACS, IBECS, BBO, and the Cochrane Library. Additionally, the Brazilian patent database (INPI - Instituto Nacional de Propriedade Industrial) was screened in order to get an overview of Brazilian technological development in the dental materials field. Two reviewers independently analyzed the documents. Only studies and patents related to dental materials were included in this review. Data regarding the material category, dental specialty, number of documents and patents, filiation countries, and the number of citations were tabulated and analyzed in Microsoft Office Excel (Microsoft Corporation, Redmond, Washington, United States). Results A total of 115,806 studies and 53 patents were related to dental materials and were included in this review. Brazil had 8% affiliation in studies related to dental materials, and the majority of the papers published were related to dental implants (1,137 papers), synthetic resins (681 papers), dental cements (440 papers), dental alloys (392 papers) and dental adhesives (361 papers). The Brazilian technological development with patented dental materials was smaller than the scientific production. The most patented type of material was dental alloys (11 patents), followed by dental implants (8 patents) and composite resins (7 patents). Conclusions Dental materials science has had a substantial number of records, demonstrating an important presence in scientific and technological development of dentistry. In addition, it is important to approximate the relationship between academia and industry to expand the technological development in countries such as Brazil.

Immunohistochemical expression of TGF-ß1 and osteonectin in engineered and Ca(OH)2-repaired human pulp tissues

Abstract The aim of the present study was to evaluate the expression of transforming growth factor-β1 (TGF-β1) and osteonectin (ON) in pulp-like tissues developed by tissue engineering and to compare it with the expression of these proteins in pulps treated with Ca(OH)2 therapy. Tooth slices were obtained from non-carious human third molars under sterile procedures. The residual periodontal and pulp soft tissues were removed. Empty pulp spaces of the tooth slice were filled with sodium chloride particles (250-425 µm). PLLA solubilized in 5% chloroform was applied over the salt particles. The tooth slice/scaffold (TS/S) set was stored overnight and then rinsed thoroughly to wash out the salt. Scaffolds were previously sterilized with ethanol (100-70°) and washed with phosphate-buffered saline (PBS). TS/S was treated with 10% EDTA and seeded with dental pulp stem cells (DPSC). Then, TS/S was implanted into the dorsum of immunodeficient mice for 28 days. Human third molars previously treated with Ca(OH)2 for 90 days were also evaluated. Samples were prepared and submitted to histological and immunohistochemical (with anti-TGF-β1, 1:100 and anti-ON, 1:350) analyses. After 28 days, TS/S showed morphological characteristics similar to those observed in dental pulp treated with Ca(OH)2. Ca(OH)2-treated pulps showed the usual repaired pulp characteristics. In TS/S, newly formed tissues and pre-dentin was colored, which elucidated the expression of TGF-β1 and ON. Immunohistochemistry staining of Ca(OH)2-treated pulps showed the same expression patterns. The extracellular matrix displayed a fibrillar pattern under both conditions. Regenerative events in the pulp seem to follow a similar pattern of TGF-β1 and ON expression as the repair processes.

Vital Pulp Therapies in Clinical Practice: Findings from a Survey with Dentist in Southern Brazil

Studies based on dentists' clinical practice possess vital relevance to understand factors leading the clinicians to choose by a specific technique over another. This study investigated which clinical conduct therapies are adopted by dentists in front of deep caries. Was evaluated how the place of work, post-graduate training and years since complete graduation influenced their decisions. A cross-sectional study was performed using a self-applied questionnaire with dentists (n=276) in Southern Brazil. Information regarding post-graduation training (specialization, master's or PhD), clinical experience (years since completing graduation) and place of work were investigated. The information regarding pulp vital therapies (materials for direct pulp capping; techniques for caries removal in deep cavities and strategies for indirect pulp capping) were collected by specific questions. Data were submitted to descriptive analysis and Exact Fischer Test. Response rate was 68% (187). The majority of dentists selected the calcium hydroxide (CH) as first material for direct (86.3%) and indirect (80.3%) pulp protection. Partial caries removal was reported by 61.9% of dentists. Less experienced clinical dentists choose partial caries removal more frequently (p=0.009), if compared with dentists graduated 10 years and up ago. The use of MTA was more common among professionals working at academic environment. Besides, MTA was not mentioned by professionals working exclusively in the public health service (p=0.003). In conclusion, the time since graduation influenced the clinical conduct related to caries removal. The choice of liner materials was influenced by dentists' workplace.

Resumo Estudos baseados na prática clínica de dentistas possuem relevância vital para o entendimento dos fatores que influenciam os clínicos na escolha de uma técnica específica em detrimento de outra. Este estudo investigou quais condutas clínicas são adotadas por dentistas frente a lesões profundas de cárie. Foi avaliado como o local de trabalho, curso de pós-graduação e tempo desde a graduação influenciaram suas decisões clínicas. Foi conduzido um estudo transversal utilizando questionários auto- aplicados à dentistas no sul do Brasil (n=276). Informações relacionadas a educação continuada (especialização, mestrado ou doutorado), experiência clínica (anos desde a graduação) e local de trabalho foram investigadas. As informações sobre terapias vitais da polpa (materiais para capeamento pulpar direto, técnicas para remoção de carie em cavidades profundas e estratégias para capeamento pulpar indireto) foram coletadas por meio de perguntas específicas. Os dados foram submetidos à análise descritiva e teste exato de Fisher. A taxa de resposta foi de 68% (187). A maioria dos dentistas selecionam o hidróxido de cálcio (HC) como primeiro material para proteção pulpar direta (86,3%) e indireta (80,3%). Remoção parcial de tecido cariado foi relatado por 61,9% dos clínicos. Dentistas com menor experiência clínica optaram pela remoção parcial de tecido cariado com mais frequência (p=0,009), quando comparados a dentistas graduados há mais de 10 anos. O uso do MTA foi mais comum entre os profissionais que trabalham em ambiente acadêmico. Além disso, o MTA não foi mencionado pelos profissionais que trabalham exclusivamente no serviço público de saúde (p=0,003). O tempo desde a graduação influenciou a conduta clínica relacionada à remoção de cárie. A escolha de materiais para proteção pulpar foi influenciada pelo local de trabalho dos dentistas.

Tenascin and Fibronectin Expression after Pulp Capping with Different Hemostatic Agents: A Preliminary Study

This study investigated the expression of extracellular matrix glycoproteins tenascin (TN) and fibronectin (FN) in pulp repair after capping with calcium hydroxide (CH), following different hemostasis protocols. Class I cavities with a pulp exposure were prepared in 42 human third molars scheduled for extraction. Different hemostatic agents (0.9% saline solution, 5.25% sodium hypochlorite and 2% chlorhexidine digluconate) were used and pulps were capped with CH cement. After 7, 30 or 90 days, teeth were extracted, formalin-fixed, and prepared for immunohistochemical technique. Hemostatic agents did not influence the expression of TN and FN. Both glycoproteins were found in the entire the pulp tissue and around collagen fibers, but were absent in the mineralized tissues. In the predentin, TN showed positive immunostaining and FN had a variable expression. Within 7 days post-treatment, a slightly more pronounced immunostaining on the pulp exposure site was observed. Within 30 days, TN and FN demonstrated a positive expression around the dentin barrier and at 90 days, a thin and linear expression of TN and FN was delimitating the reparative dentin. In conclusion, hemostatic agents did not influence TN and FN expression. Immunostaining for TN and FN was seen in different regions and periods, demonstrating their role in pulp repair.

Este estudo investigou a expressão das glicoproteínas Tenascina (TN) e Fibronectina (FN) da matriz extracelular no reparo pulpar após capeamento com hidróxido de cálcio (HC), seguindo diferentes protocolos de hemostasia. Cavidades de classe I com exposição pulpar foram preparadas em 42 terceiros molares humanos indicados para extração. Diferentes agentes hemostáticos (solução salina a 0,9%, hipoclorito de sódio a 5,25% e clorexidina a 2%) foram usados e as polpas foram capeadas com cimento de HC. Após 7, 30 ou 90 dias, os dentes foram extraídos, fixados em formalina e preparados para análise imunoistoquímica. Os agentes hemostáticos não influenciaram a expressão de TN e FN. Ambas glicoproteínas foram encontradas em todo tecido pulpar, ao redor das fibras colágenas e estiveram ausentes nos tecidos mineralizados. Na pré-dentina, a TN mostrou forte imunoexpressão e a FN teve uma expressão variável. Após 7 dias, foi observada uma expressão levemente mais pronunciada no lugar da exposição pulpar. Aos 30 dias, a TN e a FN demonstraram uma expressão mais forte sob a barreira dentinária e aos 90 dias, uma expressão fina e linear da TN e FN apresentava-se delimitando a dentina reparativa. Em conclusão, os agentes hemostáticos não influenciaram e expressão da TN e da FN. A imunoexpressão da TN e FN foi observada em diferentes regiões e períodos, demonstrando o seu papel no reparo pulpar.

Surface roughness of orthodontic band cements with different compositions

OBJECTIVES: The present study evaluated comparatively the surface roughness of four orthodontic band cements after storage in various solutions. MATERIAL AND METHODS: Eight standardized cylinders were made from 4 materials: zinc phosphate cement (ZP), compomer (C), resin-modified glass ionomer cement (RMGIC) and resin cement (RC). Specimens were stored for 24 h in deionized water and immersed in saline (pH 7.0) or 0.1 M lactic acid solution (pH 4.0) for 15 days. Surface roughness readings were taken with a profilometer (Surfcorder SE1200) before and after the storage period. Data were analyzed by two-way ANOVA and Tukey's test (comparison among cements and storage solutions) or paired t-test (comparison before and after the storage period) at 5 percent significance level. RESULTS: The values for average surface roughness were statistically different (p<0.001) among cements at both baseline and after storage. The roughness values of cements in a decreasing order were ZP>RMGIC>C>R (p<0.001). After 15 days, immersion in lactic acid solution resulted in the highest surface roughness for all cements (p<0.05), except for the RC group (p>0.05). Compared to the current threshold (0.2 µm) related to biofilm accumulation, both RC and C remained below the threshold, even after acidic challenge by immersion in lactic acid solution. CONCLUSIONS: Storage time and immersion in lactic acid solution increased the surface roughness of the majority of the tested cements. RC presented the smoothest surface and it was not influenced by storage conditions.

Oral lichenoid lesions associated with amalgam restorations: report of two cases / Lesões liquenóides bucais associadas a restaurações de amálgama: relatos de dois casos

PURPOSE: Dental amalgam has been used as a dental restoration for more than 165 years. However, some patients with these restorations may present oral lichenoid lesions (OLL). OLL are chronic oral mucosal contact reactions to dental amalgam. Their diagnosis usually is based on the direct contact of the affected mucosa with the amalgam restorations, clinical appearance, and lack of migrations. A patch-test for mercury can be performed to confirm the diagnosis. Thus, the objective this work was to discuss the occurrence of this disease and your possibilities of existing differential diagnostic. CASE DESCRIPTION: Two clinical cases were diagnosed as related to OLL. In both cases, the patients complained of a burning sensation in the oral mucosa adjacent to the amalgam restorations. The treatment involved replacing the amalgam restorations by composite. A complete remission of the painful symptoms was observed after 17 days in one case and after one month in the other, although the lesions in the oral mucosa did not disappear completely. CONCLUSION: Dentists should be aware of OLL occurrence close to amalgam restorations and should be able to diagnose it and recommend the best treatment option.

OBJETIVO: O amálgama dentário tem servido como restaurador dentário a mais de 165 anos. Entretanto, alguns pacientes com estas restaurações têm demonstrado a ocorrência de lesões liquenóides orais (LLO). As LLO são reações de contato da mucosa oral crônicas ao amálgama dentário. Geralmente, o diagnóstico da lesão é feito pelo contato direto da mucosa afeta com a restauração de amalgama, pela aparência clínica, e a ausência de migrações. Um teste de contato para o mercúrio pode ser realizado para confirmar o diagnóstico. Assim, o objetivo deste trabalho foi discutir a ocorrência desta doença e suas possibilidades de diagnóstico diferencial existentes. DESCRIÇÃO DO CASO: Dois casos clínicos foram diagnosticados como LLO. Em ambos os casos, os pacientes relataram sofrer de sensação de queimação na mucosa oral adjacente às restaurações de amálgama. Para ambos pacientes, os tratamentos envolveram a substituição das restaurações de amálgama. Completa remissão da sintomatologia dolorosa foi observada após 17 dias em um caso e após 30 dias em outro, embora as lesões na mucosa intrabucal não tenham desaparecido completamente. CONCLUSÃO: Os cirurgiões-dentistas devem estar cientes da ocorrência da LLO relacionadas a restaurações de amálgama e devem saber como fazer o diagnóstico correto para assim recomendar a melhor forma de tratamento.

Commercial swine model: an alternative for direct pulp capping studies / Modelo de suíno comercial: uma alternativa para estudos de capeamento pulpar direto

Purpose: To test the use of commercial swine as an in vivo model for studying pulp healing in response to direct capping agents. Methods: Six swine sus scrofa domesticus (Landrace X Large White) were used in the experiment. Under anesthesia, class V cavities were prepared with a pulp exposure, which was directly capped with hard-setting calcium hydroxide (Dycal®, Dentsply, Petrópolis, Rio de Janeiro, Brazil). Restorations were performed with resin-modified glass ionomer cement (Vitremer® 3M Espe St Paul, MN, USA). After 7 or 70 days (n = 6), the animals were died; the teeth were extracted, formalin-fixed and prepared for histological evaluation. The biological response was categorized using the following criteria: inflammatory response, soft tissue organization, reactionary and, reparative dentin formations. Results: After seven days pulp in most specimens inflammatory response was present and after 70 days reparative dentin was formed at the pulp exposure area in almost all the animals. These responses were similar to those previously reported in human in similar periods of evaluation. In addition, the swine model showed another advantages: easy handling and economical feasibility compared to other animal models. Conclusion: The commercial swine model seems to be an adequate animal model to test pulp biocompatibility.

Objetivo: O objetivo do estufo foi analisar o uso de suínos industriais como modelo para a avaliação da resposta pulpar a procedimentos de capeamento direto. Metodologia: Em 6 suínos sus scrofa domesticus foram realizados preparos cavitários classe V até expor o tecido pulpar. Após a hemorragia ter sido controlada, o local exposto foi capeado com cimento de hidróxido de cálcio (Dycal®, Dentsply, Petrópolis, Rio de Janeiro, Brasil) e na sequência os dentes foram restaurados com cimento de ionômero de vidro (Vitremer® 3M Espe St Paul, MN, USA). As respostas teciduais foram analisadas após 7 (n = 6) e 70 (n = 6) dias. Os animais foram abatidos, os dentes extraídos e, posteriormente, processados para análise morfológica descritiva quanto aos seguintes critérios: resposta inflamatória, organização do tecido pulpar, dentina reacional e reparativa. Resultados: Após 7 dias observou-se a presença de infiltrado inflamatório e decorridos 70 dias, dentina reparativa foi formada na área de exposição em quase todos os espécimes, sendo estes achados similares aos achados previamente reportados em capeamentos realizados em humanos. Além disso, o modelo demonstrou outras vantagens, tais como a viabilidade econômica (baixo custo comparado a outros modelos animais) e facilidade de manuseio. Conclusão: O uso de suínos de raças comerciais pode ser considerado como alternativa para os testes de biocompatibilidade dentino-pulpar.