Compressive strength of esthetic restorative materials polymerized with quartz-tungsten-halogen light and blue LED

Este estudo comparou a resistência à compressão de uma resina composta e de um compômero, fotoativados com luz halógena convencional de quarto-tungstênio (QTH) (XL 300, 3M/SPE) e LED azul (SmartLite PS; Dentsply/De Trey). Foram confeccionados 40 espécimes em forma de disco usando uma matriz bipartida de politetrafluoretileno (4,0 mm de diâmetro x 8,0 mm de altura) em que o material foi inserido incrementalmente. O tempo de polimerização de cada incremento foi de 40 s para a luz halógena convencional e de 10 s para o LED. Os espécimes foram aleatoriamente alocados em 4 grupos (n=10), de acordo com a fonte de luz e com o material restaurador. Depois de armazenadas em água destilada a 37°C ± 2°C por 24 h, a resistência à compressão dos espécimes foi testada em uma máquina universal de ensaios com célula de carga de 500 kgf a uma velocidade de carregamento de 0,5 mm/min. Os dados (em MPa) foram analisados estatisticamente por ANOVA e teste de Student-Newman-Keuls (p<0,05). Para a resina composta, a fotopolimerização com luz halógena não produziu diferença estatisticamente significante (p>0,05) em sua resistência à compressão quando comparada à fotopolimerização com LED. Contudo, a fotopolimerização do compômero com a luz halógena resultou em uma resistência à compressão significativamente maior que a feita o LED (p>0,05). A resina composta apresentou resistência à compressão significativamente maior que a do compômero, independente da fonte de luz. Concluiu-se que a resistência à compressão dos materiais fotopolimerizados com luz halógena e LED foi influenciada pela densidade de energia empregada e pela composição química dos materiais restauradores estéticos.

Caries formation around restorative composite and glass ionomer cement

This in vitro study evaluated the demineralization around restorations class V made on the buccal and lingual surfaces of teeth when using different restorative materials. Thirty extracted teeth were randomly divided into 3 groups (n=10) according to the restorative material: Group I - Fuji II LC (GC America Inc., Alsip, Illinois, USA), Group II - Tetric (Ivoclar Vivadent AG, Schaan, Liechtenstein) and Group III - Chelon Fil (3M/ESPE., Seefeld, Germany). The teeth were submitted to a pH-cycling model associated to a thermocycling model. Sections were made and the specimens were analyzed under a polarized light microscopy as for the presence of demineralization. Measurements were performed and the results were subjected to statistical analysis using Anova and Tukey´s Test (α=0.05). Mean values of demineralization depth (µm) according to each positions showed that the demineralization was significantly reduced when Chelon Fil (Group III) was used for all depths, when compared to fluoridated resin materials. Also, it was verified that non-fluoridated resin material, composite resin Tetric, had the lowest inhibitory effect on the development of demineralization.

Eroded dentin does not jeopardize the bond strength of adhesive restorative materials

This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva) and eroded dentin (pH cycling model - 3x / cola drink for 7 days). Specimens were then reassigned according to restorative material: glass ionomer cement (Ketac (TM) Molar Easy Mix), resin-modified glass ionomer cement (Vitremer (TM)) or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250). Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37 degrees C. The failure mode was evaluated using a stereomicroscope (400x). Bond strength data were analyzed with two-way ANOVA and Tukey's post hoc tests (alpha = 0.05). Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001). For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested.

Bonding of restorative materials to dentin with various luting agents

The aim was to compare eight types of luting agents when used to bond six indirect, laboratory restorative materials to dentin. Cylinders of the six restorative materials (Esteticor Avenir [gold alloy], Tritan [titanium], NobelRondo [feldspathic porcelain], Finesse All-Ceramic [leucite-glass ceramic], Lava [zirconia], and Sinfony [resin composite]) were ground and air-abraded. Cylinders of feldspathic porcelain and glass ceramic were additionally etched with hydrofluoric acid and were silane-treated. The cylinders were luted to ground human dentin with eight luting agents (DeTrey Zinc [zinc phosphate cement], Fuji I [conventional glass ionomer cement], Fuji Plus [resin-modified glass ionomer cement], Variolink II [conventional etch-and-rinse resin cement], Panavia F2.0 and Multilink [self-etch resin cements], and RelyX Unicem Aplicap and Maxcem [self-adhesive resin cements]). After water storage at 37°C for one week, the shear bond strength of the specimens (n=8/group) was measured, and the fracture mode was stereomicroscopically examined. Bond strength data were analyzed with two-factorial analysis of variance (ANOVA) followed by Newman-Keuls' Multiple Range Test (?=0.05). Both the restorative material and the luting agent had a significant effect on bond strength, and significant interaction was noted between the two variables. Zinc phosphate cement and glass ionomer cements produced the lowest bond strengths, whereas the highest bond strengths were found with the two self-etch and one of the self-adhesive resin cements. Generally, the fracture mode varied markedly with the restorative material. The luting agents had a bigger influence on bond strength between restorative materials and dentin than was seen with the restorative material.

Avaliação da microinfiltração marginal em cavidades classe II de molares decíduos restauradas com diferentes cimentos de ionômero de vidro

O objetivo desta pesquisa foi avaliar a microinfiltração em restaurações classe II realizadas com diferentes cimentos de ionômero de vidros em molares decíduos. Para tal, foram selecionados quarenta molares decíduos humanos a partir de um Banco de Dentes. Nas faces mesial e distal de cada dente foram preparadas cavidades classe II com dimensões padronizadas. Em seguida, os dentes foram divididos em oito grupos experimentais correspondentes ao material restaurador utilizado: grupo MXR (Maxxion R); grupo VDR (Vidrion R); grupo VTR (Vitremer); grupo VTF (Vitro Fill LC); grupo FUJ (Fuji IX); grupo KTM (Ketac Molar); grupo VMO (Vitro Molar); grupo MGS (Magic Glass ART). Ao término de vinte e quatro horas de imersão em água destilada, os dentes foram mantidos em solução de nitrato de prata a 50% pelo mesmo período e, então, em solução reveladora de radiografias (hidroquinona, Kodak) por quinze minutos. Os dentes foram então seccionados através do centro das restaurações, e observados em lupa estereoscópica sob o aumento de quarenta vezes. A microinfiltração foi graduada co base em escores relacionados à penetração do nitrato de prata na interface adesiva. Os resultados, após submetidos à análise estatística, demonstraram que nenhum dos materiais testados impediu completamente a microinfiltração. No entanto, o Vitremer apresentou os escores mais baixos, seguido do Ketac Molar e do Fuji IX. Os materiais Magic Glass ART, Vitro Molar, Vitro Fill LC e Vidrion R apresentaram comportamento intermediário em relação aos demais, enquanto o Maxxion R apresentou os piores resultados. Com base na metodologia empregada e nos resultados obtidos, pode-se concluir que nenhum dos materiais testados foi capaz de impedir completamente a microinfiltração, apesar de apresentarem graus varáveis de suscetibilidade a esse fenômeno, destacando-se, entre eles o Vitremer, o Ketac Molar e o Fuji IX por apresentarem baixos níveis de microinfiltração, seguidos do Magic Glass ART, Vitro Molar, Vitro Fill LC e Vidrion R. Em contrapartida, o Maxxion R apresentou os piores resultados, fato constatado pelos altos escores de microinfiltração registrados.

Utilização de materiais restauradores autocondicionantes na prevenção de descoloração coronária causada por minociclina

O objetivo desse estudo foi comparar a capacidade de dois materiais restauradores em prevenir a descoloração coronária causada pela minociclina como medicação intracanal e propor uma técnica de fácil implementação para encorajar o uso da pasta tri-antibiótica para desinfecção do sistema de canais radiculares durante procedimentos de regeneração pulpar sem perda estética. Cem dentes foram selecionados, seus canais radiculares foram instrumentados e divididos em quatro grupos de acordo com o tratamento dentinário utilizado: Grupo OB- Agente adesivo OptiBond All-In-One (KERR); Grupo U200- Cimento resinoso auto-condicionante e auto adesivo RelyX U200 (3M ESPE); Grupo MIN- Sem revestimento; Grupo CN- Sem revestimento (controle negativo). Em todos os grupos, com exceção do CN, foi utilizada pasta de minociclina como medicação intracanal coberta por uma bolinha de algodão e vedados com restauração provisória. As medições de cor foram realizadas com um espectrofotômetro no início do estudo (T0), e 7(T7), 14 (T14), 21 (T21) e 28 dias (T28) pós-minociclina. Os resultados obtidos foram submetidos à análise estatística. As diferenças de cor (E*) foram crescentes nos grupos CN, OB, U200 e MIN, respectivamente. A diferença de luminosidade (L*) foi também crescente nos grupos CN, OB, U200 e MIN, respectivamente. Houve diferença significante entre os grupos MIN e CN, e entre os grupos MIN e U200 (p<0,05). O eixo amarelo-azul (b*) não apresentou alteração de cor significante (p>0,05). Uma alteração de cor significante no eixo vermelho-verde (a*) foi observada no grupo MIN em relação ao grupo CN (p<0,05). Portanto, conclui-se que a técnica foi fácil de ser implementada, ambos materiais reduziram a descoloração da coroa causada pela pasta de minociclina mas foram ineficazes em impedi-la completamente.

Efeito do reforço estrutural em cimentos de ionômero de vidro com fibras de vidro em restaurações classe II de molares decíduos: estudo in vitro

Os objetivos deste estudo foram medir o efeito do reforço estrutural com a adição de fibras de vidro, na resistência ao teste de tração diametral e no selamento marginal de restaurações classe II com cimento de ionômero de vidro em molares decíduos. Fibras de vidro foram incorporadas ao pó do cimento de ionômero de vidro (CIV) na concentração de 40%. As fibras usadas foram do tipo E com comprimentos que variavam de 50m a 210m. A propriedade mecânica foi verificada através do teste de tração diametral, após 15 minutos, 24 horas e 15 dias de estocagem em água. Corpos de prova foram preparados com as dimensões de 4x8 mm para cada intervalo de tempo de acordo com as normas do fabricante e padrões internacionais. Para o teste de microinfiltração foram usados segundos molares decíduos hígidos, onde foram preparadas cavidades classe II padronizadas em dois grupos: a) controle com CIV Ketac Molar Easymix (3M/ESPE); e b) teste Ketac Molar Easymix (3M/ESPE); reforçado com fibras. Estes dentes foram restaurados e deixados em água por 24h e, a seguir, imersos em solução de nitrato de prata a 50% pelo mesmo período. Para que houvesse a precipitação de sais de prata os dentes foram colocados em solução reveladora de radiografias por 15 minutos. Para analisar a microinfiltração os espécimes foram seccionados na direção mesio-distal obtendo duas amostras de observação para cada cavidade restaurada. Os resultados do teste mecânico foram analisados através dos testes de variância ANOVA e de múltiplas variáveis de Tukey. Os resultados da microinfiltração foram analisados através do teste de MANN-WHITNEY. Com a metodologia empregada foi possível concluir que houve aumento dos valores de tração diametral no CIV com a adição de fibras de vidro. Para os intervalos de 24 horas e 15 dias, o CIV reforçado com fibras apresentou valores de tração diametral superiores àqueles do CIV não reforçado, havendo diferença significativa estatística (p<0,05) para os intervalos testados. No teste de microinfiltração os grupos mostraram valores semelhantes de infiltração marginal. A adição das fibras de vidro tipo E aumentou a resistência à tração diametral do CIV testado em relação ao grupo controle e as fibras de vidro não alteraram a adesão do cimento reforçado.

Revisão bibliográfica

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

Ionómero de vidro vs. resina composta em odontopediatria

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

Impact of Referral Protocols on the Dental Management of Patients Undergoing Treatment for Head and Neck Oncology in Northern Ireland

Objective: To evaluate the handling, by a group of practice-based researchers, of a recently introduced bulk fill resin-based composite restorative material, Filtek Bulk Fill Restorative (3M ESPE).

Methods: The twelve selected evaluators were sent explanatory letters, a pack of the material under investigation to use for 8 weeks, and a questionnaire.

Results: The evaluators rated the ease of use of the bulk fill restorative the same as the previously used posterior composite material. The provision of one shade only for evaluation may have compromised the score for aesthetic quality. No post-operative sensitivity was reported.

Conclusions: The bulk fill material was well received as indicated by the high number of evaluators who would both purchase the material and recommend it to colleagues.

Clinical relevance: A recently introduced bulk fill restorative material achieved a rating for handling which was similar to the evaluators’ previously used resin composite, although there were some concerns regarding the translucency of the material.

Clinical assessment of postoperative sensitivity in posterior composite restorations

This incidence of postoperative sensitivity was evaluated in resin-based posterior restorations. Two hundred and ninety-two direct restorations were evaluated in premolars and molars. A total of 143 Class I and 149 Class 11 restorations (MO/OD and MOD) were placed in patients ranging in age from 30 to 50 years. After the cavity preparations were completed, a rubber dam was placed, and the preparations were restored using a total-etch system (Prime & Bond NT) and a resin-based restorative material (TPH Spectrum). The patients were contacted after 24 hours and 7, 30 and 90 days postoperatively and questioned regarding the presence of sensitivity and the stimuli that triggered that sensitivity. The Chi-square and Fisher's Exact Test were used for statistical analysis. Evaluation at 24 hours after restorative treatment revealed statistically significant differences among the types of cavity preparations restored and the occurrence of postoperative sensitivity (p=0.0003), with a higher frequency of sensitivity in Class H MOD restorations (26%), followed by Class II MO/DO (15%) and Class I restorations (5%). At 7, 30 and 90 days after restorative treatment, there was a decrease in the occurrence of sensitivity for all groups. The percentage of sensitivity among the groups was not significantly different. This study shows that the occurrence of sensitivity is correlated with the complexity of the restoration.

Single crowns versus conventional fillings for the restoration of root filled teeth

BackgroundEndodontic treatment, involves removal of the dental pulp and its replacement by a root canal filling. Restoration of root filled teeth can be challenging due to structural differences between vital and non-vital root filled teeth. Direct restoration involves placement of a restorative material e.g. amalgam or composite directly into the tooth. Indirect restorations consist of cast metal or ceramic (porcelain) crowns. The choice of restoration depends on the amount of remaining tooth which may influence long term survival and cost. The comparative in service clinical performance of crowns or conventional fillings used to restore root filled teeth is unclear.ObjectivesTo assess the effects of restoration of endodontically treated teeth (with or without post and core) by crowns versus conventional filling materials.Search methodsWe searched the following databases: the Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE via OVID, EMBASE via OVID, CINAHL via EBSCO, LILACS via BIREME and the reference lists of articles as well as ongoing trials registries. There were no restrictions regarding language or date of publication. Date of last search was 13 February 2012.Selection criteriaRandomised controlled trials (RCTs) or quasi-randomised controlled trials in participants with permanent teeth which have undergone endodontic treatment. Single full coverage crowns compared with any type of filling materials for direct restoration, as well as indirect partial restorations (e.g. inlays and onlays). Comparisons considered the type of post and core used (cast or prefabricated post), if any.Data collection and analysisTwo review authors independently assessed trial quality and extracted data.Main resultsOne trial judged to be at high risk of bias due to missing outcome data, was included. 117 participants with a root filled premolar tooth restored with a carbon fibre post, were randomised to either a full coverage metal-ceramic crown or direct adhesive composite restoration. At 3 years there was no reported difference between the non-catastrophic failure rates in both groups. Decementation of the post and marginal gap formation occurred in a small number of teeth.Authors' conclusionsThere is insufficient evidence to support or refute the effectiveness of conventional fillings over crowns for the restoration of root filled teeth. Until more evidence becomes available clinicians should continue to base decisions on how to restore root filled teeth on their own clinical experience, whilst taking into consideration the individual circumstances and preferences of their patients.

Direct Esthetic Restorations Based on Translucency and Opacity of Composite Resins

Light dynamics is a relevant phenomenon with respect to esthetic restorations, as incorrect analysis of the optical behavior of natural dentition may lead to potential clinical failures. The nature of incident light plays a major role in determining the amount of light transmission or reflection, and how an object is perceived depends on the nature of the light source. Natural teeth demonstrate translucency, opalescence, and fluorescence, all of which must be replicated by restorative materials in order to achieve clinical success. Translucency is the intermediary between complete opacity and complete transparency, making its analysis highly subjective. In nature, the translucency of dental enamel varies from tooth to tooth, and from individual to individual. Therefore, four important factors must be considered when appraising translucency. Presence or absence of color, thickness of the enamel, degree of translucency, and surface texture are essential components when determining translucency. State-of-the-art resin composites provide varying shades and opacities that deliver a more faithful reproduction of the chromaticity and translucency/opacity of enamel and dentin. This enables the attainment of individualized and customized composite restorations. The objective of this article is to provide a review of the phenomena of translucency and opacity in the natural dentition and composite resins, under the scope of optics, and to describe how to implement these concepts in the clinical setting.CLINICAL SIGNIFICANCEChoosing composite resins, based on optical properties alone, in order to mimic the properties of natural tooth structures, does not necessarily provide a satisfactory esthetic outcome. In many instances, failure ensues from incorrect analysis of the optical behaviors of the natural dentition as well as the improper use of restorative materials. Therefore, it is necessary to implement a technique that enables a restorative material to be utilized to its full potential to correctly replicate the natural teeth.(J Esthet Restor Dent 23:73-88, 2011).

Customized fiber glass posts. Fatigue and fracture resistance

Purpose: To evaluate the root fracture strength of human single-rooted premolars restored with customized fiberglass post-core systems after fatigue simulation. Methods: 40 human premolars had their crowns cut and the root length was standardized to 13 mm. The teeth were endodontically treated and embedded in acrylic resin. The specimens were distributed into four groups (n=10) according to the restorative material used: prefabricated fiber post (PFP), PFP+accessory fiber posts (PFPa), PFP+unidirectional fiberglass (PFPf), and unidirectional fiberglass customized post (CP). All posts were luted using resin cement and the cores were built up with a resin composite. The samples were stored for 24 hours at 37 degrees C and 100% relative humidity and then submitted to mechanical cycling. The specimens were then compressive-loaded in a universal testing machine at a crosshead speed of 0.5 mm/minute until fracture. The failure patterns were analyzed and classified. Data was submitted to one-way ANOVA and Tukey's test (alpha= 0.05). Results: The mean values of maximum load (N) were: PFP - 811.4 +/- 124.3; PFPa - 729.2 +/- 157.2; PFPf - 747.5 +/- 204.7; CP - 762.4 +/- 110. Statistical differences were not observed among the groups. All groups showed favorable restorable failures. Fiberglass customized post did not show improved fracture resistance or differences in failure patterns when compared to prefabricated glass fiber posts. (Am J Dent 2012;25:35-38).

A retrospective look at esthetic resin composite and glass-ionomer Class III restorations: A 2-year clinical evaluation

Objective: A restorative material for Class III cavities must, besides being functional, be esthetically satisfactory, providing good working conditions and several shade and color options. A clinical evaluation was initiated to compare the suitability of resin composite and glass-ionomer cement materials for such restorations.Method and materials: Forty-two Class III conservative cavities, esthetically important because of facial extensions, were selected. Resin composite restorations were placed in 21 cavities, and the remaining 21 were restored with glass-ionomer cement. The following characteristics were studied: color or-esthetics, anatomic shape, surface texture, staining, marginal infiltration, dental plaque retention, and occurrence of fracture. After 24 months, the restorations were evaluated.Results: the only statistically significant difference between the resin composite and glass-ionomer cement restorations in the experimental period involved color or esthetics.Conclusion: Resin composites and glass-ionomer materials provide excellent functional and esthetic results in Class III cavities when properly indicated.