Marginal adaptation of lithium disilicate ceramic crowns cemented with three different resin cements.

Objectives: The cementation process and cementation materials have an influence on the marginal adaptation of restorations. The gap could be affected by thermal and mechanical loading (TCML). The computerized x-ray microtomography (μCT) method offers the possibility of measuring the marginal gap without destruction of the restoration.

Influence of extremely high irradiances on the micromechanical properties of a nano hybrid resin based composite.

Purpose: To investigate in vitro the effect of extremely high irradiance light-emitting diode (LED) light curing units (LCU) with different exposure distances and curing modes on the micromechanical properties of a nano hybrid resin based composite.

Methods: 72 resin based composite (RBC) (Kalore) specimens with 2 mm thickness were cured using two high irradiance LED LCUs (Bluephase 20i and FlashMax P3) at 0 and 7 mm exposure distances. The curing conditions were:a) Bluephase 20i - 10 seconds - High power; b) Bluephase 20i - 15 seconds - High power; c) Bluephase 20i - 5 seconds - Turbo; d) Bluephase 20i - 15 seconds - Soft start; e) FlashMax P3 - 4 mm tip cover - 3 seconds; f) FlashMax P3 - without tip cover - 3 seconds.

Axiographic results of CAD/CAM-assisted microvascular, fibular free flap reconstruction of the mandible: A prospective study of 21 consecutive cases.

Virtual planning and guided reconstruction of the mandible following ablative surgery have become standard procedures in reconstructive surgery. Many advantages regarding operation time, morphology, bony fit, and consolidation have been described, but analyses of the functional outcome of virtually planned mandibular reconstructions are lacking. We prospectively analyzed 21 consecutive cases of mandibular reconstructions using CAD/CAM-assisted microvascular, fibular free flaps in operations between July 2014 and January 2016 at a single center.

Intraoral Repair of a Glass-Ceramic Restoration With Nanohybrid Ormocers: A Case Report.

The interest in repairing failed restorations has been growing; such a procedure may prolong the life span of defective direct and indirect dental restorations. The intraoral repair using resin-based composite materials has major benefits, as it preserves the main body of the restoration, avoids unnecessary removal of sound tooth structure, is an easy and fast treatment, avoids additional appointments, and is inexpensive. This case report demonstrates the use of nanohybrid Ormocer®, or organically modified ceramic, materials.

A new method for the evaluation of the accuracy of full-arch digital impressions in vitro.

Objectives: Introducing a new approach to evaluate the accuracy of digital impression methods for full-arch scans, avoiding "best-fit alignment."

Materials And Methods: A lower jaw model with a straight metal bar between the second molars of both quadrants was directly digitized using an intraoral scanner (True Definition, TRD, n = 12) and indirectly digitized (D810, CON, n = 12) after impression and plaster cast. A dataset of the bar from a coordinate measuring machine served as reference (REF).

Bulk fill restoratives: to cap or not to cap--that is the question?

Objectives: To assess the cuspal deflection and cervical microleakage scores of standardised large mesio-occlusal-distal (MOD) cavities filled with different restoration protocols: (1) conventional resin restoratives, (2) bulk fill flowable base materials 'capped' with a conventional dimethacrylate resin-based composite (RBC) or (3) bulk fill resin restorative materials.

Methods: Standardised MOD cavities were prepared in sixty-four sound maxillary premolar teeth and randomly allocated to eight groups. Restorations were placed in conjunction with a universal bonding system and resin restorative materials were irradiated with a quartz-tungsten-halogen light-curing-unit.

Complete mouth rehabilitation after transposition osteotomy based on intraoral scanning: an experimental approach.

This article describes the surgical and prosthodontic treatment of a patient with severe dysgnathia combined with amelogenesis imperfecta. To the authors' knowledge, this is the first treatment report to describe the application of intraoral scanning for a complete mouth reconstruction. After transposition osteotomy, the treatment included the simultaneous fabrication of antagonistic computer-aided design/computer-aided manufactured (CAD/CAM) long-term interim restorations for the maxilla and mandible and the establishment of a new centric relation position and adequate vertical dimension of occlusion.

Optical properties of manually and CAD/CAM-fabricated polymers.

The aim of this study was to compare the light translucency and fluorescence 5 manually and 11 CAD/CAM polymer materials to a glass-ceramic material. Light-transmission was measured using a spectrophotometer. Overall light transmission (n=40) was calculated as the integration (tc (λ) dλ [10(-5)]) of all tc values for the wavelengths from 400 to 700 nm.

Effects of aging and irradiation time on the properties of a highly translucent resin-based composite.

This study investigated the effects of aging and irradiation time on the macro- and micro-mechanical properties of a highly translucent nanohybrid composite (IPS Empress Direct, Trans Opal shade, Ivoclar Vivadent). Flexural strength, flexural modulus, indentation modulus, Vickers hardness, and creep were measured after being irradiated with different durations (5, 10, 20, and 40 s) and aged under different conditions (24 h at 37°C in water; 5,000 times of thermocycling between 5°C and 55°C followed by 4-week storage in artificial saliva or alcohol). Rate of cure was also measured for these four irradiation times at composite specimen surface and at 2 mm depth.

Effect of heat application on the mechanical behaviour of glass ionomer cements.

Objectives: The aim of this study was to examine the long-term effect of heat on the mechanical behaviour of conventional highly viscous glass ionomer cements. Besides, the effect of storage time was evaluated.

Materials And Methods: Five cements (ChemFil Rock, Riva Self Cure, Fuji IX GP Fast, Equia and Ketac Molar Aplicap) were evaluated using three different preparation methods: no heat application, application of heat by means of a LED curing unit for 20 and 60 s.

Effect of gloss and heat on the mechanical behaviour of a glass carbomer cement.

Objectives: The effect of gloss and heat on the mechanical behaviour of a recently launched glass carbomer cement (GCP, GCP dental) was evaluated and compared with resin-modified glass ionomer cements (Fuji II LC, GC and Photac Fil Quick Aplicap, 3M ESPE).

Methods: 120bar-shaped specimens (n=20) were produced, maintained in distilled water at 37°C and tested after one week. The GCP specimens were cured with and without heat application and with and without gloss.

Treatment concept with CAD/CAM-fabricated high-density polymer temporary restorations.

Tooth wear in younger patients is perceived worldwide as an increasing problem. Its etiology is multifactorial (erosion, abrasion, attrition), and its treatment is challenging for the dental practitioner specifically when a great loss of the vertical dimension of occlusion has occurred. The aim of this article is to present a treatment approach for complex cases with high loss of tooth structure using computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated temporary high-density polymer restorations without any preparations.

Accuracy of digital models obtained by direct and indirect data capturing.

Objectives: With direct and indirect digitalisation, two access points to CAD/CAM-generated restorations are available. The aim of this study was to compare the accuracy of the single steps of both approaches by comparing construction datasets using a new methodology.

Material And Method: Twelve test datasets were generated in vitro (1) with the Lava Chairside Oral Scanner (COS) (2) by digitizing polyether impressions (IMP) and (3) by scanning the referring gypsum cast by the Lava Scan ST laboratory scanner (ST) at a time.

Evaluation of a conventional glass ionomer cement with new zinc formulation: effect of coating, aging and storage agents.

Objective: The study focused on a recently launched conventional glass ionomer cement (GIC) with a particular chemical formulation of both, filler and acrylic liquid, by analysing its mechanical behaviour in comparison to three conventional GICs. Furthermore, the effect of resin coating and storage conditions was evaluated.

Materials And Methods: Three commercially available GICs were chosen: Riva Self Cure (SDI), Fuji IX Fast (GC) and Fuji IX GP Extra/Equia (GC).

The effect of aging on the mechanical properties of nanohybrid composites based on new monomer formulations.

Objectives: Nanohybrid resin-based composites (RBCs) containing new types of matrix monomers such as dimer acid-based dimethacrylate or tricyclodecane-urethane are assumed to show decreased water uptake and therefore better resistance to hydrolytic degradation than RBCs using bisphenol A diglycidyl methacrylate (BisGMA) due to their hydropobic nature. Our study aimed to analyze the effect of aging on six nanohybrid RBCs, of which two are using these new types of monomers, with regard to differences in the mechanical properties of the materials.

Materials And Methods: Diametral tensile strength (DTS), Vickers hardness (HV), and creep were measured.

Investigations towards nano-hybrid resin-based composites.

Objective: Clinical data indicate an increased trend in material fracture as reason for failure in composite restorations, questioning whether modern resin-based composites (RBCs) are able to fulfil the rising aesthetical demands and to provide at the same time a sufficient mechanical stability also in larger cavities. Nano-hybrid RBCs are promoted as materials with improved mechanical properties. The aim of this study was to analyse differences in mechanical properties within and between modern flowable and non-flowable nano-hybrid and micro-hybrid RBCs by measuring mechanical properties at macro- and micro-scale.

Dentin infiltration ability of different classes of adhesive systems.

Objectives: This study evaluates the dentin infiltration ability of various types of adhesives and compares four classes of adhesive systems with regard to this property. The infiltration is determined quantitatively, characterized as tag length and ratio of infiltration, and qualitatively, characterized as homogeneity, regularity, and continuity of the resin tags.

Materials And Methods: Flat dentin surfaces from 140 halves of caries-free molars were bonded with four classes of adhesive systems.

Enhancing the predictability of complex rehabilitation with a removable CAD/CAM-fabricated long-term provisional prosthesis: a clinical report.

Implementing any definitive prosthetic treatment of the residual edentulous ridge involves several risks. The patient's expectations may not be completely fulfilled as such treatment procedures include major changes in function and esthetics. Innovative materials, such as high-density polymers based on a highly cross-linked polymethylmetacrylate (PMMA) or composite resin for CAD/CAM-manufacturing are an alternative treatment option.

The mechanical stability of nano-hybrid composites with new methacrylate monomers for matrix compositions.

Objectives: Dimer acid based metacrylates and TCD-urethane are promoted as new monomers of nano-hybrid resin based composites as alternatives for the conventional BisGMA. Investigations of this study focused on the mechanical and the storage behavior of nano-hybrid resin based composites (RBCs) composed of these new types of monomers in comparison to RBCs using BisGMA.

Methods: Flexural strength and modulus were determined in a three-point-bending test.

Resin composite restorative materials.

This paper surveys the most important developments in resin-based dental composites and focuses on the deficits (e.g. polymerization shrinkage) and strengths of the materials and their clinical implications.

Fracture toughness of dental restorative materials.

The ability of a restorative material to withstand fracture is of crucial importance especially in stress-bearing area. Therefore, the study aims to analyse the fracture toughness of a large number of dental restorative materials categories. The fracture toughness (K(IC)) of 69 restorative materials belonging to ten materials categories-micro-hybrid, nanofilled, microfilled, packable, ormocer-based, and flowable resin-based composites (RBC), compomers and flowable compomers, as well as glass ionomer cements (GIC) and resin-modified GIC was measured by means of the single-edge notched-beam method after storing the samples (n = 8) for 24 h in distilled water.

Effect of curing mode on the micro-mechanical properties of dual-cured self-adhesive resin cements.

Light supplying to luting resin cements is impeded in several clinical situations, causing us to question whether materials can properly be cured to achieve adequately (or adequate) mechanical properties. The aim of this study was therefore to analyse the effect of light on the micro-mechanical properties of eight popular dual-cured self-adhesive resin cements by comparing them with two conventional, also dual-cured, resin cements. Four different curing procedures were applied: auto-polymerisation (dark curing) and light curing (LED unit, Freelight 2, 20 s) by applying the unit directly on the samples' surface, at a distance of 5 and 10 mm.

Investigations on a methacrylate-based flowable composite based on the SDR™ technology.

Objective: Monomer development for a reduced shrinkage of composite materials still challenges the modern research. The purpose of this study was to analyse the shrinkage behavior of an innovative composite material for dental restorations based on a resin system that is claimed to control polymerization kinetics having incorporated a photoactive group within the resin.

Methods: Shrinkage stress development within the first 300s after photoinitiation, gel point as well as micro-mechanical properties (Vickers hardness HV, modulus of elasticity E, creep Cr and elastic-plastic indentation work W(e)/W(tot)) were evaluated (n = 10).

Is the soft-start polymerisation concept still relevant for modern curing units?

Shrinkage stress, degree of cure and mechanical properties are contradicting properties, forcing to a compromise between an adequate curing and low stress at the interface tooth-restoration. The purpose of this study was to quantify this relations for a micro-hybrid composite, by analysing in real time the development of degree of cure at depths of 2 and 6 mm, shrinkage stress and curing time until gelation, as well as the variation of micro-mechanical properties with depth, after curing with 13 regimes of one halogen and two light-emitting diode (LED) curing units. A nano-dynamic mechanical test was additionally performed on selected regimes (Ramp, Pulse and Fast Cure) of the same curing unit.

Polymerization composite shrinkage evaluation with 3D deformation analysis from microCT images.

Objectives: The aim of this study was to develop a method to experimentally determine and visualize the direction and amount of polymerization shrinkage.

Methods: We modified a composite to include 1.5 wt% traceable glass beads.