Clinical survival and performance of premolars restored with direct or indirect cusp-replacing resin composite restorations with a mean follow-up of 14 years.

Objectives: The objective is to evaluate the long-term clinical survival and performance of direct and indirect resin composite restorations replacing cusps in vital upper premolars.

Methods: Between 2001 and 2007, 176 upper premolars in 157 patients were restored with 92 direct and 84 indirect resin composite restorations as part of an RCT. Inclusion criteria were fracture of the buccal or palatal cusp of vital upper premolars along with a class II cavity or restoration in the same tooth.

Thickness and Substrate Effect on the Mechanical Behaviour of Direct Occlusal Veneers.

Purpose: This study aimed to evaluate the fracture resistance and stress magnitude of occlusal veneers made of conventional or flowable resin composites at different minimal thicknesses bonded on enamel or dentin.

Material And Methods: A total of 120 sound bovine incisors were flattened and used as substrates (enamel or dentin) for the restorations. The teeth were embedded into polymethyl methacrylate and allocated into 4 groups according to the resin composite (Clearfil AP-X PLT and Clearfil Majesty Flow, Kuraray Dental) and substrate.

Comparison of wear between occlusal splint materials and resin composite materials.

Tooth wear in bruxing patients often results in a need for treatment with composite restorations. In some cases, bruxing patients receive an occlusal splint as a protective means as well. However, the wear between these opposing materials has not been investigated yet.

Influence of dentin and enamel on the fracture resistance of restorations at several thicknesses.

Purpose: To investigate the effect of substrate and thickness on the fracture resistance of bonded dental restorative materials.

Methods: Cylindrical restorations (d = 4.0 mm) of resin composites Filtek Supreme XTE, Clearfil AP-X, Lava Ultimate and glass-ceramic IPS e.

The Resin-Bonded Fixed Partial Denture as the First Treatment Consideration to Replace a Missing Tooth.

The resin-bonded fixed partial denture (RB-FPD) is the first restorative treatment option to be considered in cases where one or more teeth are missing. The indications for implants, conventional FPDs, and adhesive FPDs, considering the general and dental conditions of the patient, are discussed in this article. When the RB-FPD is the chosen option, a direct or indirect technique, a cantilever-type or fixed-fixed design, and materials to be used need to be selected.

Mechanical performance of implant-supported posterior crowns.

Statement Of Problem: The fracture of implant-supported restorations, especially of the veneering layer, is a common problem in dentistry. Monolithic ceramic or resin restorations might help solve this problem.

Purpose: The purpose of this in vitro study was to obtain additional insight into the risk of fracture of implant-supported restorations.

Influence of duration and dose of metformin on cobalamin deficiency in type 2 diabetes patients using metformin.

Metformin use is associated with cobalamin (vitamin B12) deficiency. However, the influence of both duration and dose of metformin is unclear. Studies using holotranscobalamin, a marker for cellular cobalamin deficiency, are scarce.

Randomized control trial of composite cuspal restorations: five-year results.

The objective of this randomized control trial was to compare the five-year clinical performance of direct and indirect resin composite restorations replacing cusps. In 157 patients, 176 restorations were made to restore maxillary premolars with Class II cavities and one missing cusp. Ninety-two direct and 84 indirect resin composite restorations were placed by two operators, following a strict protocol.

[Considerations in the treatment of tooth wear].

Since the origin of tooth wear (attrition, abrasion and erosion) is multi-factorial, its diagnosis is complicated but vital. The so-called Tooth Wear Evaluation System, introduced earlier, makes a systematic diagnostic approach possible. The system consists of various modules, which can be used by the practitioner depending on the goal.

The effect of proximal contour on marginal ridge fracture of Class II composite resin restorations.

Objectives: To compare the marginal ridge fracture strength of Class II composite resin restorations placed with a straight or contoured matrix band using composite resins with different modulus of elasticity.

Methods: In 60 artificial first molars standardized MO-preparations were ground. Two matrix systems were used: (1) A straight matrix (Standard Tofflemire Matrix, KerrHawe) in Tofflemire retainer (Produits Dentaire).

A randomized clinical trial of cusp-replacing resin composite restorations: efficiency and short-term effectiveness.

Purpose: This study aimed to assess the efficacy and short-term effectiveness of the morphology and function of direct and indirect cusp-replacing resin composite restorations.

Materials And Methods: In 94 patients, 106 cusp-replacing restorations for maxillary premolars were fabricated to restore Class II caries lesions with 1 cusp missing. Fifty-four direct (Clearfil AP-X) and 52 indirect (Estenia) resin composite restorations were placed following a strict protocol.

Can internal stresses explain the fracture resistance of cusp-replacing composite restorations?

The aim of this study was to explore and compare the results of occlusal load application to cusp-replacing composite restorations, studied by means of finite element (FE) analysis and in vitro load tests. A three-dimensional (3D) FE model was created with a set up similar to an in vitro load test that assessed the fatigue resistance of upper premolars with buccal cusp-replacing resin composite restorations. Occlusal load was applied to two geometries (with and without palatal cuspal coverage), and the tooth-restoration interface and composite material stresses were calculated.

A comparison of fatigue resistance of three materials for cusp-replacing adhesive restorations.

Objectives: To investigate the fatigue resistance and failure behaviour of cusp-replacing restorations in premolars using different types of adhesive restorative materials.

Methods: A class 2 cavity was prepared and the buccal cusp was removed in an extracted sound human upper premolar. By using a copy-milling machine this preparation was copied to 60 human upper premolars.

In vitro fracture resistance of fiber reinforced cusp-replacing composite restorations.

Objectives: To assess the fracture resistance and failure mode of fiber reinforced composite (FRC) cusp-replacing restorations in premolars.

Methods: Forty-five extracted sound upper premolars were randomly divided into three groups. Identical MOD cavities with simulated buccal cusp fracture and height reduction of the palatal cusp were prepared.

[Research methods in dentistry 5. The finite element method].

The finite element method is a commonly applied experimental research technique. The method comprises computer simulation of constructions under load and of internal mechanical processes, which enables the study of effects of geometrical and material variations. The analysis shows internal stresses and, consequently, predictions can be made of possible failure.

Fatigue resistance of teeth restored with cuspal-coverage composite restorations.

Purpose: This study assessed the influence of palatal cuspal coverage on the in vitro fatigue resistance and failure mode of Class II resin composite restorations including replacement of the buccal cusp in premolars.

Materials And Methods: A master model was made of a maxillary premolar with an MOD amalgam cavity and a simulated fracture of the buccal cusp from the isthmus floor to the CEJ. Using a copy-milling machine, this preparation was copied to 20 extracted human maxillary premolars (group A).

Role of the Rhoa/Rho kinase system in flow-related remodeling of rat mesenteric small arteries in vivo.

In small arteries, a chronic blood flow reduction leads to inward hypotrophic remodeling, while a chronic blood flow elevation induces outward hypertrophic remodeling. The RhoA/Rho kinase system was shown to be modulated by shear stress, and to be involved in other kinds of vascular remodeling. The aim of this study was to investigate the role of RhoA/Rho kinase in flow-related small artery remodeling.

Does layering minimize shrinkage stresses in composite restorations?

Polymerization shrinkage of resin composites may impair restoration longevity. It is hypothesized that layering, rather than bulk, techniques result in less stress in the tooth-restoration complex. The aim of this study was to compare shrinkage stresses for different restorative techniques used for cusp-replacing restorations with direct resin composite.

[Minimal invasive treatment of cuspal fractures of premolars].

This article describes the cusp-replacing adhesive restoration as a minimally invasive alternative for crowns after cuspal fracture of premolars. To demonstrate the importance of this treatment option for daily practice, the results of an incidence study of cuspal fractures are reported. Subsequently, the development of clinical guidelines and procedures as applied in a clinical study of adhesive cusp-replacing restorations are described.

Fracture strength of cusp replacing resin composite restorations.

Purpose: To assess the influence of an additional shoulder preparation on the fracture strength of a cusp-replacing direct resin composite restoration in a premolar that previously had an amalgam MOD restoration followed by fracture of a cusp.

Materials And Methods: Two preparation designs were tested. In extracted sound premolars an MOD amalgam cavity was simulated followed by fracture of a cusp (Group A).

[A finite element model of a cusp-replacing adhesive restoration].

This article describes the development of a three-dimensional finite element model of a premolar, based on a micro-scale computed tomographic data-acquisition technique. Using the model shrinkage stresses were analysed during and after the polymerisation process of resin composite. The stress patterns generated were three-dimensional.

A three-dimensional finite element model of the polymerization process in dental restorations.

Restoration of dental restorations with resin composite is hampered by shrinkage of the material during the polymerization process. In this study, we simulated the polymerization process in a detailed three-dimensional finite element model of a human upper premolar with a cusp-replacing restoration. It was analyzed how the stress patterns changed during polymerization and it was assessed whether immediate failure of the restoration is likely to occur and if so, which locations within the restoration are at highest risk and what the clinical implications of these findings are for clinical practice.

A survey of cusp fractures in a population of general dental practices.

Purpose: This study was conducted to expand the knowledge on the incidence of complete cusp fractures of posterior teeth in Dutch general practices.

Materials And Methods: During a 3-month period, data were obtained from 28 general practitioners, representing 46,394 patients. For each new case of complete cusp fracture, clinicians recorded information using a standard form with questions relating to location of the fracture, cause of fracture, and restorative status of the tooth prior to the cusp fracture.

[Layer thickness of dental adhesives. Relation between layer thickness and viscosity].

Objective: To investigate the viscosity of two dental adhesives in relation to the adhesive layer thickness.

Design: In vitro study.

Methods: The viscosity of several dental adhesives has been determined with a reogoneometer.

Generation of 3-D finite element models of restored human teeth using micro-CT techniques.

Purpose: This article describes the development of a three-dimensional finite element model of a premolar based on a microscale computed tomographic (CT) data-acquisition technique. The development of the model is part of a project studying the optimal design and geometry of adhesive tooth-colored cusp-replacing restorations.

Materials And Methods: The premolar was digitized with a micro CT scanner with a resolution of 13 microns.