Polymerization kinetics of 3D-printed orthodontic aligners under different UV post-curing conditions.

Background: The purpose of the study was to measure the degree of conversion (DC) of direct-printed aligners (DPA) that were post-cured under ambient and nitrogen atmosphere at specific time intervals and investigate the kinetics of polymerization reaction of this material.

Methods: A total of 48 aligners were produced in 4 printing series by a 3D printer with TC-85DAC resin (Graphy Inc). From each series of printing, 12 aligners were included.

An Evaluation of Experimental Calcium Ion-Leachable Nanocomposite Glass Ionomer Cements.

Glass ionomer cements (GICs) are among the main restorative dental materials used broadly in daily clinical practice. The incorporation of clay nanoparticles as reinforcing agents is one potential approach to improving GIC properties. This study aims to investigate whether the incorporation of calcium-modified clay (Ca-clay) nanoparticles in conventional GICs alters their structural characteristics, along with their physicochemical and mechanical properties.

Synthesis and Characterization of Dental Nanocomposite Resins Reinforced with Dual Organomodified Silica/Clay Nanofiller Systems.

Quaternary ammonium (QA) compounds have been widely studied as potential disinfectants in dental restorative materials. The present work investigates whether the gradual displacement of nanosilica by QA-clay nanoparticles may have an impact on the physicochemical and mechanical properties of dental nanocomposite resins. For this purpose, Bis-GMA/TEGDMA-based composite resins were initially synthesized by incorporating 3-(trimethoxysilyl)propyl methacrylate (γ-MPS)-modified nanosilica/QA-clay nanoparticles at 60/0, 55/5, 50/10, 40/20, and 30/30 wt% filler loadings.

Cardiotoxicity of Chemical Substances: An Emerging Hazard Class.

(1) Background: Human health risks and hazards from chemical substances are well regulated internationally. However, cardiotoxicity, is not defined as a stand-alone hazard and therefore there are no defined criteria for the classification of substances as cardiotoxic. Identifying and regulating substances that cause cardiovascular adverse effects would undoubtedly strengthen the national health systems.

Children and Parents' Awareness Regarding Potential Hazards Derived from the Use of Chemical Products in Greece.

Over the last decades, human activities prompted the high production and widespread use of household chemical products, leading to daily exposure of humans to several chemicals. The objective of this study was to investigate the frequency of chemicals' use by children and parents in Greece and estimate the level of risk awareness and understanding among them. A total of 575 parents and children were asked to answer an anonymous, closed-ended, validated, and self-administered questionnaire.

Cytotoxic Evaluation and Determination of Organic and Inorganic Eluates from Restorative Materials.

Over the last years, diverse commercial resin-based composites have dominated as dental filling materials. The purpose of the present study was to determine organic and inorganic eluates from five restorative materials using GC/MS and ICP-OES and to compare the effect on cell survival of human gingival fibroblasts of a conventional and a bioactive resin. Five commercially available restorative materials were employed for this study: Activa Bioactive Restorative, ENA HRi, Enamel plus HRi Biofunction, Fuji II LC Capsule, and Fuji IX Capsule.

Synthesis of Novel Dental Nanocomposite Resins by Incorporating Polymerizable, Quaternary Ammonium Silane-Modified Silica Nanoparticles.

Diverse approaches dealing with the reinforcement of dental composite resins with quaternary ammonium compounds (QAC) have been previously reported. This work aims to investigate the physicochemical and mechanical performance of dental resins containing silica nanofillers with novel QAC. Different types of quaternary ammonium silane compounds (QASiC) were initially synthesized and characterized with proton nuclear magnetic resonance (H-NMR) and Fourier transform infrared (FTIR) spectroscopy.

Microtensile Bond Strength Between Resin-Matrix CAD/CAM Ceramics and Resin Cement after Various Surface Modifications and Artificial Aging.

Purpose: To evaluate the effect of different surface modification methods on the microtensile bond strength (μTBS) of four resin-matrix CAD/CAM ceramics after artificial aging.

Materials And Methods: Specimens of four CAD/CAM materials (Shofu Block HC, Lava Ultimate, Brilliant Crios, and Vita Enamic) were prepared and divided into four groups. Each group received one of the following treatments: group 1 (INT): no surface modification; group 2: sandblasting with 29-μm Al2O3 particles (SB); group 3: hydrofluoric acid etching (9%) + silane (HF+Si); group 4: sandblasting with 30-μm particles of the CoJet system (CJ).

Flow characteristics and alkalinity of novel bioceramic root canal sealers.

Objective: This study aimed to examine the physical properties (pH and flow) of 2 novel bioceramic sealers.

Materials And Methods: The tested sealers were a calcium hydroxide sealer (Sealapex) and 2 bioceramic sealers (BioRoot RCS and TotalFill BC Sealer). Flow measurements were conducted according to ISO 6876/2012, with a press method of 0.

Safe use of chemicals and risk communication among dentists and dental students in Greece.

Use of chemicals, most often classified for intrinsic hazards, is rather common among dentists. To date, no data have been recorded in the European Union (EU) on dentists' awareness regarding the safe use of chemicals. In the EU regulatory framework, two Regulations with wide applications, namely Regulations (EC) 1907/2006 (REACH) and 1272/2008 (CLP), have been introduced to protect human health and the environment and clearly communicate hazards posed by chemicals to workers and consumers.

Organic Eluates Derived from Intermediate Restorative Dental Materials.

A great number of different types of materials have been used in dentistry as intermediate restoratives. Among them, new resin-based bases have been released in the dental market. The present study focuses on the identification of the organic eluates released from such materials and the study of their surface microstructure in combination with their corresponding elemental composition.

Pit and fissure nanocomposite sealants reinforced with organically modified montmorillonite: A study of their mechanical properties, surface roughness and color stability.

The aim of the present work was to investigate the effect of the different organically modified nanoclays on clinically significant properties of new synthesized dental pit and fissure nanocomposite sealants. Their morphological characteristics were examined by means of X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). A universal testing machine was used to conduct the flexural and compression tests.

Synthesis and Characterization of Dental Nanocomposite Resins Filled with Different Clay Nanoparticles.

Nanotechnology comprises a promising approach towards the update of dental materials.The present study focuses on the reinforcement ofdental nanocomposite resins with diverse organomodified montmorillonite (OMMT) nanofillers. The aim is to investigate whether the presence of functional groups in the chemical structure of the nanoclay organic modifier may virtually influence the physicochemical and/or the mechanical attitude of the dental resin nanocomposites.

Investigation of the chemical profile and cytotoxicity evaluation of organic components eluted from pit and fissure sealants.

The aim of this study was to identify organic components eluted from five resin dental sealants using gas chromatography and mass spectrometry (GC/MS) after 1-day and 40-days storage and the effect of sealants on cell survival of cultured fibroblasts. Five resin materials were studied: BeautiSealant (SHOFU), Clinpro (3M/ESPE), Conseal F (SDI), Grandio Seal (VOCO) and Helioseal Clear (Ivoclar/Vivadent). The organic monomers detected were butylated hydroxytoluene (BHT), bis-phenol-A (BPA), camphoroquinone (CQ), diethylenglycoldimethacrylate (DEGDMA), 4N, N-dimethylaminobenzoic acid butylethoxyester (DMABEE), hydroxyethylmethcrylate (HEMA), hydroquinone monomethylether (MEHQ), triethylene glycol dimethacrylate (TEGDMA), tetrabutylammonium tetrafluoroborate (TBATFB), triphenylstibane (TPSb).

Influence of material and surface treatment on composite repair shear bond strength.

Objectives: The aim of this study is to investigate the influence of the composite material and surface treatment to the bond strength when repairing an aged composite surface with new composite.

Materials And Methods: One hundred and sixty resin blocks of methacrylate composite and silorane composite prepared and aged in artificial saliva for 6 months. Specimens treated either with a diamond bur (DB) or air abrasion (AA), conditioned with orthophosphoric acid (OA) or sodium hypochloride (SH) and repaired with methacrylate or silorane composite using the corresponding adhesive system.

Bonding of Composite to Base Materials: Effects of Adhesive Treatments on Base Surface Properties and Bond Strength.

Purpose: To evaluate the effects on the surface properties (morphology, roughness, microhardness, composition) and bond strength to composite of four types of base cements (Equia-Fil/EQF, Angelus white MTA/MTA, Biodentin/BDN and IRM/IRM) when treated with phosphoric acid etching (PAE) or two self-etch adhesives (Select One Prime & Bond and Clearfil S3 Bond).

Materials And Methods: Disk-shaped specimens were prepared and stored until complete setting. The surfaces before and after treatments were examined by stereomicroscopy, optical profilometry, ATR-FTIR, and LV-SEM/EDX.

Cytotoxicity of a New Calcium Silicate Endodontic Sealer.

Introduction: Resin sealers with biocompatible and bioactive additives have been used in clinical practice. Recently, a calcium silicate root canal sealer was introduced under the name BioRoot RCS (Septodont, Saint Maur-des-Fossés, France). The aim of this study was to evaluate the effects of BioRoot RCS on cell survival and proliferation of cultured cells in parallel with an epoxy resin sealer with calcium phosphate and calcium oxide and a salicylate resin sealer with mineral trioxide aggregate filler.

Color match of luting composites and try-in pastes: the impact on the final color of CAD/CAM lithium disilicate restorations.

Aim: Color matching of the restoration to the adjacent teeth can be difficult due to the translucency of the ceramic and the visual exposure of the polymerized resin cement through the ceramic material. The aim of this study was to identify color differences between try-in pastes and the corresponding luting resin composites.

Materials And Methods: The materials tested were Variolink Veneer, Variolink Try-In, Variolink Esthetic LC, and Variolink Esthetic Try-In.

Management of bilateral invasive cervical resorption lesions in maxillary incisors using a novel calcium silicate-based cement: A case report.

Invasive cervical resorption is a pathologic process leading to progressive and usually destructive loss of tooth structure. The pathogenic mechanism is not completely understood and the diagnosis may be challenging. The aim of this article is to present an unusual case of bilateral presence of invasive cervical resorption lesions in maxillary central incisors and to discuss the treatment procedures using a novel repair material.

Combined and independent cytotoxicity of sodium hypochlorite, ethylenediaminetetraacetic acid and chlorhexidine.

Aim: To evaluate the capacity of commonly used root canal irrigants to induce cytotoxic effects, when applied singly or in combination. The hypothesis tested was that the irrigants were less cytotoxic when applied in combination than independently.

Methodology: MRC5 cells were grown as monolayer cultures at 37 °C in an atmosphere containing 5% CO2 in air and 100% relative humidity.

Color match of resin composites to intact tooth structure.

Introduction: The optical properties of dental restorative materials have a dramatic effect on patient esthetics, which may be compromised by the poor blending effect of composites resins at the composite-tooth interface.

Objective: The objective of this study was to evaluate the color-matching ability and the blending effects of 3 different composite resins when restoring natural teeth.

Methods: Three commercially available composites and 60 central incisors were used for this experiment.

Accidental ingestion of an air-water syringe tip during routine dental treatment: a case report.

Accidental ingestion of instruments or their components is a possible complication of dental treatment. Although in many cases the foreign object can pass through the gastrointestinal tract without any need for surgical intervention to retrieve it, sometimes such incidents can be life-threatening. This paper reports a case of accidental ingestion of an air-water syringe tip during routine dental treatment for which endoscopic retrieval was required.

The reparability of contemporary composite resins.

Objective: The objective was to investigate the way that various surface treatments could influence the bond strength of the repair of methacrylate (MC) and silorane (SIL) composites.

Materials And Methods: A total of 160 MC and SIL cylindrical specimens were polymerized and aged in artificial saliva solution for 7 days. Depending on the following surface treatment (diamond bur or air abrasion), and the conditioning procedure (orthophosphoric acid or sodium hypochlorite), 16 groups were formed and repaired either with MC, either with SIL composite.

Pulp response to dentine adhesives: A study on mature human pulps.

Objective: To clinically investigate the antibacterial effects of a commercially available self-etch 12-methacryloyloxy- dodecylpyridinium bromide (MDPB)-containing adhesive system in comparison with its respective non-MDPB-containing adhesive and to evaluate the pulp responses when in use on human teeth.

Materials And Methods: Sixty-two viable human teeth scheduled for extraction were used. Class V cavities were prepared on the buccal surfaces of the teeth and filled with the tested materials (Protect Bond/Clearfil AP-X, SE Bond/Clearfil AP-X and Dycal/Ketac Fill Plus) as a control group, according to manufacturer's recommendations.

Effect of extraction media and storage time on the elution of monomers from four contemporary resin composite materials.

Introduction: The purpose of this study was to examine the effect of different extraction media, including culture media, as well as storage times on the elution of monomers from modern dental composites.

Materials And Methods: FOUR CONTEMPORARY COMPOSITE MATERIALS WERE TESTED: (a) Clearfil Majesty Esthetic (Kuraray), (b) Esthet X (DENTSPLY), (c) Filtek Silorane (3M ESPE), and (d) Admira (Voco). Forty-eight specimens were made.