ABSTRACT
This study aimed to evaluate Nd:YAG laser, calcium phosphate, and adhesive system effect as different pretreatments in different protocols on dentin permeability (DP) and bond strength (BS). Fifty human dentin discs were used (4 mm in diameter and 1,5 mm in height). Specimens were divided into five groups (n = 10): (A): adhesive system (control); (AL): adhesive system + Nd:YAG laser; (LAL): Nd:YAG laser + adhesive system + Nd:YAG laser; (PAL): calcium phosphate-based dentin desensitizer TeethMate + adhesive system + Nd:YAG laser; and group (PLAL): Nd:YAG laser + calcium phosphate-based dentin desensitizer + adhesive system + Nd:YAG laser. All materials were used according to the manufacturers' instructions. The specimens were submitted to artificial aging (5,000 thermal cycles and 12 × 104 mechanical cycles) then a bond test was performed. DP was measured using the split chamber model. Data were submitted to one-way analysis of variance (ANOVA), paired t-test, RM ANOVA, and Tukey test (p < 0.05). All treatments were effective in DP reduction. For BS, the groups PAL and PLAL had improved BS with a statistically significant difference of the control group (A). Nd:Yag laser irradiation and calcium phosphate-based desensitizing agents significantly reduced DP, and the association between them could improve the BS on resin-human dentin interface.
ABSTRACT
Evidence regarding the effect of the onlay preparation design for different CAD/CAM restorative materials considering the preservation of cusps is lacking. Molars were 3D-modeled in four preparation designs for onlay restoration: traditional design with functional cusp coverage (TFC), non-retentive design with functional cusp coverage (NFC), traditional design with non-functional cusp coverage (TNFC) and non-retentive design with non-functional cusp coverage (NNFC). The restorations were simulated with two CAD/CAM restorative materials: LD-lithium disilicate (IPS e.max CAD) and RC-resin composite (GrandioBloc). A 100 N axial load was applied to the occlusal surface, simulating the centric contact point. Von Mises (VM) and maximum principal (Pmax) stress were evaluated for restorations, cement layer and dental substrate. The non-retentive preparation design reduced the stress concentration in the tooth structure in comparison to the conventional retentive design. For LD onlays, the stress distribution on the restoration intaglio surface showed that the preparation design, as well as the prepared cusp, influenced the stress magnitude. The non-retentive preparation design provided better load distribution in both restorative materials and more advantageous for molar structure. The resin composite restoration on thenon-functional cusp is recommended when the functional cusp is preserved in order to associate conservative dentistry and low-stress magnitude.
ABSTRACT
O presente trabalho teve como objetivos: (1) relatar uma série de casos e apresentar uma metodologia para medição de desgaste usando software de metrologia comparando dois tipos de materiais em blocos CAD-CAM (dissilicato de lítio e resina composta) usados para restaurações onlay; (2) avaliar, in silico, a distribuição de tensões de dois materiais restauradores, IPS emax CAD e Grandio Blocs, em dois tipos de desenho de preparo dentário para onlay envolvendo cúspides funcionais ou não funcionais. (1) O estudo clínico foi registrado para avaliação do comitê de ética local e foi realizado com voluntários que necessitaram de procedimento restaurador indireto, seguindo os critérios de inclusão/exclusão. Quatro restaurações do tipo onlay (IPS emax CAD e GrandioBlocs) foram confeccionadas pelo método CAD-CAM chairside por um único operador treinado. A alocação dos tratamentos foi feita de forma aleatória. Após a cimentação das restaurações, a avaliação foi feita por examinador calibrado, não sendo o operador, nos períodos de 7 dias, 6 meses e 1 ano. Neste estudo foi analisada a quantidade de desgaste das restaurações por software de medição de dados (Gom Inspect) com acompanhamento de 6 meses e 1 ano com 4 pacientes avaliados sendo 2 restaurações de GrandioBlocs e 2 para IPS emax CAD. O resultado foi representado por um mapeamento de cores onde cada tonalidade representa uma quantidade de desgaste. O resultado obtido pelas imagens foi insignificante mostrando leve diferença nas imagens com restauração de GrandioBlocs. (2) Os molares foram modelados em quatro desenhos de preparação para restauração onlay: preparo tradicional com cobertura da cúspide funcional (TFC), preparo não retentivo com cobertura da cúspide funcional (NFC), preparo tradicional com cobertura da cúspide não funcional (TNFC), preparo não retentivo com cobertura de cúspide não funcional (NNFC). As restaurações foram simuladas com dois materiais restauradores CAD / CAM: LD - dissilicato de lítio (IPS emax CAD) e RC - resina composta (GrandioBlocs). Uma carga axial de 100 N foi aplicada à superfície oclusal simulando o ponto de contato cêntrico. As tensões de Von Mises (VM) e as tensões principais máximas (Pmax) foram avaliadas tanto para restaurações onlay, camada de cimento e substrato dentário. O desenho do preparo não retentivo melhorou a concentração de tensões na estrutura dentária em comparação com o desenho retentivo convencional. Para as onlays LD, a distribuição de tensões na superfície interna da restauração mostrou que o desenho da preparação influenciou a distribuição de tensões, bem como a opção de cúspide preparada. O desenho do preparo não retentivo proporcionou melhor distribuição de carga em ambos os materiais restauradores e mais vantajoso para a estrutura dentária. A restauração de resina composta em cúspides não funcionais é recomendada quando a cúspide funcional está preservada, para ser mais conservadora.
The aim of the present study was (1) to report a series of cases and to present a methodology for measurement of wear using metrology software comparing two types of CAD-CAM materials (lithium disilicate and composite resin) used for onlay restorations; (2) to evaluate, in silico, the stress distribution of two restorative materials, IPS emax CAD and Grandio Blocs, in two types of dental preparation design for onlay involving functional or non-functional cusps. (1) The clinical study was registered for evaluation by the local ethics committee and was carried out with volunteers who needed an indirect restorative procedure, following the inclusion / exclusion criteria. Four onlay restorations (IPS emax CAD and Grandio Blocs) were made using the chairside CAD-CAM method by a single trained operator. The allocation of treatments was done at random. After the cementation of the restorations, the assessment was made by a calibrated examiner, not being the operator, in the periods of 7 days, 6 months and 1 year. In this study, the amount of wear of the restorations was analyzed by data measurement software with 6-month and 1-year follow-up with 4 patients evaluated, 2 of which were GrandioBlocs and 2 for , IPS emax CAD restorations. The result is represented by a color mapping where each shade represents a quantity of wear. The result obtained by the images was insignificant, showing a slight difference in the images with restoration of GrandioBlocs. (2) Molars were modeled in four preparation designs for onlay restoration: traditional design with functional cusp coverage (TFC), non- retentive design with functional cusp coverage (NFC), traditional design with non-functional cusp coverage (TNFC), non-retentive design with non-functional cusp coverage (NNFC). Restorations were simulated with two CAD-CAM restorative materials: LD - lithium-disilicate (IPS emax CAD) and RC - resin composite (GrandioBloc). A 100 N axial load was applied to the occlusal surface simulating the centric contact point. Von Mises (VM) and maximum principal (Pmax) stresses were evaluated for onlay restorations, the cement layer and the dental substrate. The non-retentive preparation design improved the stress concentration in the tooth structure in comparison to the conventional retentive design. For LD onlays, the stress distribution on the restoration intaglio surface showed that the preparation design influenced the stress distribution as well as the prepared cusp option. The design of non-retentive preparation provided better load distribution in both restorative materials and more advantageous for tooth structure. The resin composite restoration on non- functional cusp is recommended when functional cusp is preserved, in order to be more conservative.
Subject(s)
Ceramics , Computer-Aided Design , Composite Resins , Finite Element Analysis , InlaysABSTRACT
OBJECTIVE: The aim of this study was to evaluate the influence of a liner on the clinical performance of deep posterior restorations performed with bulk-fill composite. METHODS: 30 subjects received two restorations on deep preparations in posterior teeth, without pulpal exposure, after selective carious-tissue removal in one-stage. The internal walls reached the inner quarter of dentin, but with a radiographically detectable zone of firm dentin remaining. The pulpal protection using a layer of glass ionomer composite liner (Ionoseal, Voco) was applied in just one preparation. The adhesive system Futurabond U (Voco) was applied in all preparations, which were restored with the bulk-fill pure Ormocer nanohybrid composite (Admira Fusion Xtra - Voco), in up to 4â¯mm thick increments. All restorations were evaluated using the FDI criteria after 7 days, 6, 12 and 24 months postoperatively. RESULTS: After 24-months, 25 patients attended the recall and 50 restorations were evaluated. The Fisher's statistical analysis (5%) showed no difference between the techniques for the esthetic, functional and biological properties. No postoperative sensitivity was reported for both groups. CONCLUSION: The application of a liner did not influence the clinical performance of deep restorations with bulk-fill Ormocer composite. CLINICAL RELEVANCE: The application of a liner with a GIC-based material did not have a significant effect on the clinical performance of bulk-fill restorations and seems to be unnecessary for the material tested.
