Low and high hydrogen peroxide concentrations of in-office dental bleaching associated with violet light: an in vitro study.

Objectives: This study aims to assess hydrogen peroxide (HP) penetration within the pulp chamber, color change (CC), physical-chemical properties, and temperature using in-office different concentration bleaching gels with or without violet light.

Materials And Methods: Fifty teeth were divided into five groups (n = 10) based on the HP concentration bleaching gels used (6% and 35%) and the used violet light (with or without). HP penetration within the pulp chamber was measured using UV-Vis.

The capacity of conservative preparations for lithium disilicate glass-ceramic laminates luted with different resin cements to mask different substrate shades: A minimally invasive esthetic approach.

Objective: Demonstrate the ability of 0.5 mm thickness lithium disilicate laminates associated with resin cement to mask different substrate saturations.

Methods: 60 specimens (n = 5) were prepared with CAD/CAM lithium disilicate glass-ceramic IPS e.

INitial Steps of Insulin Action in Parotid Glands of Male Wistar Rats.

The parotid gland is the largest salivary gland. It produces watery saliva, rich in proteins (amylase, lysozymes, and antibodies). Due to the gland's morphological cytoarchitecture composed of only serous acini, it contributes almost 50% of total salivary volume upon stimulation.

Prefabricated resin veneer: A case report of a simplified restorative technique.

the aim of the study was to describe the step-by-step of clinical cases using prefabricated composite resin veneers (PCRVs), manufactured with the composite Brilliant New Generation (Coltene, Altstätten, Switzerland). Direct composite veneers presented some drawback as the difficult of execution and color instability of the composite over the time. The simplified application of the PCRVs presented as an interesting alternative in cases of smile asymmetry, large deficient restorations and discolored tooth.

A comparative study of bulk-fill composites: degree of conversion, post-gel shrinkage and cytotoxicity.

Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk-fill and two conventional composites. Degree of conversion was determined by FTIR spectroscopy; post-gel volumetric shrinkage was determined using the strain gauge method; and cytotoxicity in human fibroblasts was evaluated indirectly by the MTT assay.

In vitro analysis of a local polymeric device as an alternative for systemic antibiotics in Dentistry.

The development of a biodegradable material with antimicrobial properties for local applications is required in the prevention and treatment of infectious diseases. The objective of this study was to produce blends of poly-L-lactide acid (PLLA) synthetic polymer associated with several antimicrobials, as an alternative in the prevention and treatment of infections, as well as to evaluate its cytotoxicity, release of antimicrobials and inhibit bacteria growth. Blends of PLLA added with 20% Amoxicillin, Metronidazole, Clindamycin or Azithromicyn were used to produce Films (F) or Meshs (M) by casting and electrospinning methods, respectively.

Micro-CT and FE-SEM enamel analyses of calcium-based agent application after bleaching.

Objectives: The objective of the present study is to evaluate the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on bleached enamel.

Materials And Methods: A bleaching agent (35% hydrogen peroxide) was applied, 4 × 8 min on premolar teeth (n = 8). A CPP-ACP paste was applied for 7 days.

Evaluation of Intra Root Canal Er,Cr:YSGG Laser Irradiation on Prosthetic Post Adherence.

Purpose: In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear-layer-free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber-reinforced composite posts.

Phosphoric acid concentration affects dentinal MMPs activity.

Objectives: To evaluate whether the concentration of phosphoric acid (PA) has an effect on the proteolytic activity of sound human demineralized dentin. It is hypothesized that the activity of matrix-bound and extracted enzymes depends on the PA concentration used to demineralize dentin.

Methods: One-gram aliquots of mid-coronal human dentin powder were demineralized with 1wt%, 10wt% and 37wt% PA.

Polymerization development of "low-shrink" resin composites: Reaction kinetics, polymerization stress and quality of network.

Objectives: To evaluate "low-shrink" composites in terms of polymerization kinetics, stress development and mechanical properties.

Methods: "Low-shrink" materials (Kalore/KAL, N'Durance/NDUR, and Filtek P90/P90) and one control (Esthet X HD/EHD) were tested. Polymerization stress (PS) was measured using the Instron 5565 tensometer.

Temperature increase at the light guide tip of 15 contemporary LED units and thermal variation at the pulpal floor of cavities: an infrared thermographic analysis.

In this study, a comprehensive investigation on the temperature increase at the light guide tip of several commercial light-emitting diode (LED) light-curing units (LCUs) and the associated thermal variation (ΔT) at the pulpal floor of dental cavities was carried out. In total, 15 LEDs from all generations were investigated, testing a quartz-tungsten-halogen (QTH) unit as a reference. The irradiance level was measured with a power meter, and spectral distribution was analyzed using a spectrometer.

Qualitative SEM/EDS analysis of microleakage and apical gap formation of adhesive root-filling materials.

Objective: The aim of this study was to compare the correspondence between gap formation and apical microleakage in root canals filled with epoxy resin-based (AH Plus) combined or not with resinous primer or with a dimethacrylate-based root canal sealer (Epiphany).

Material And Methods: Thirty-nine lower single-rooted human premolars were filled by the lateral condensation technique (LC) and immersed in a 50-wt% aqueous silver nitrate solution at 37ºC (24 h). After longitudinal sectioning, epoxy resin replicas were made from the tooth specimens.

Microshear bond strength of self-etching systems associated with a hydrophobic resin layer.

Purpose: To evaluate in vitro the microshear bond strength of adhesive systems applied to dentin according to manufacturers' instructions, associated or not with a hydrophobic layer of unfilled resin.

Materials And Methods: Six self-etching adhesives (Clearfil SE Bond, Kuraray Medical; AdheSE, Ivoclar Vivadent; Xeno III, Dentsply; I Bond, Heraeus-Kulzer; Bond Force, Tokuyama; Futurabond DC, Voco) were tested. The labial dentin of sixty bovine incisors was exposed, and the teeth were divided into two groups according to the application or not of an extra hydrophobic resin layer (Scotchbond Multi Purpose Plus, bottle 3).

Composite pre-heating: effects on marginal adaptation, degree of conversion and mechanical properties.

Objectives: This study evaluated the effect of composite pre-polymerization temperature and energy density on the marginal adaptation (MA), degree of conversion (DC), flexural strength (FS), and polymer cross-linking (PCL) of a resin composite (Filtek Z350, 3M/ESPE).

Methods: For MA, class V cavities (4 mm x 2 mm x 2 mm) were prepared in 40 bovine incisors. The adhesive system Adper Single Bond 2 (3M/ESPE) was applied.

Effect of light irradiation on tooth whitening: enamel microhardness and color change.

The aim of this study was to evaluate the influence of light exposure associated with 35% hydrogen peroxide (Pola Office, SDI, Melbourne, Vic., Australia) or 15% hydrogen peroxide (BriteSmile, Discus, Culver City, CA, USA) on the microhardness and color changes of bovine enamel. Experimental groups were Britesmile + Light (BL) (15% hydrogen peroxide + plasm arc; 4 x 20 minutes), Britesmile + No Light (BN) (BL, no light), Pola office + Light (PL) (35% hydrogen peroxide + LED; 4 x 8 minutes), and Pola office + No light (PN) (PL, no light).

Polymerization stress, flow and dentine bond strength of two resin-based root canal sealers.

Aim: To compare two resin-based root canal sealers (AH Plus and dual cure Epiphany) in terms of flow, polymerization stress and bond strength to dentine.

Methodology: Flow was evaluated by measuring the diameter of uncured discs of sealer (0.5 mL) after 7 min compression (20N) between two glass plates (n = 5).

Influence of photoactivation protocol and light guide distance on conversion and microleakage of composite restorations.

Purpose: To evaluate the effect of light guide distance and the different photoactivation methods on the degree of conversion (DC) and microleakage of a composite.

Methods And Materials: Three photoactivation protocols (600 mW/cm2 x 40 seconds; 400 mW/cm2 x 60 seconds or 200 mW/cm2 x 20 seconds, followed by 500 mW/cm2 x 40 seconds) and three distances from the light source (0, 3 or 7 mm) were tested. Cylindrical specimens (5 mm diameter; 2 mm tall; n=3) were prepared for the DC test (FT-Raman).

Influence of etching time on bond strength in dentin irradiated with erbium lasers.

The purpose of this in vitro study was to evaluate the effect of etching time on the tensile bond strength (TBS) of a conventional adhesive bonded to dentin previously irradiated with erbium:yttrium-aluminum-garnet (Er:YAG) and erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers. Buccal and lingual surfaces of 45 third molars were flattened until the dentin was exposed and randomly assigned to three groups (n = 30) according to the dentin treatment: control (not irradiated), irradiated with Er:YAG (1 W; 250 mJ; 4 Hz; 80.6 J/cm(2)) laser or Er,Cr:YSGG (4 W; 200 mJ; 20 Hz; 71.

Effects of Nd:YAG laser irradiation on the hybrid layer of different adhesive systems.

Purpose: The aim of this in vitro study was to evaluate the microtensile bond strength (microTBS) and hybrid layer morphology of different adhesive systems, either followed by treatment with Nd:YAG laser irradiation or not. Previous studies have shown the effects of Nd:YAG laser irradiation on the dentin surface at restoration margins, but there are few reports about the significance of the irradiation on the hybrid layer.

Materials And Methods: The flattened coronal and root dentin samples of 24 bovine teeth were randomly divided into 8 groups, according to the adhesive system used -- Scotchbond Multi Purpose (SBMP) or Clearfil SE Bond (CSEB) -- and were either irradiated with Nd:YAG or not, with different parameters: 0.

Conditioning effect on dentin, resin tags and hybrid layer of different acidity self-etch adhesives applied to thick and thin smear layer.

Objectives: to assess the conditioning effect (CE) of self-etch adhesives of different acidity applied to thick and thin smear layer (SL), the corresponding resin tags (RT) and hybrid layer (HL).

Methods: Twenty-seven molars had their occlusal dentin exposed and were sectioned into two halves. Each of them was ground with a 60 or 600-grit SiC paper, respectively for thick and thin SL production.

The influence of handling on the elasticity of addition silicone putties.

The handling of vinyl polysiloxane (addition silicone) impression putties with latex gloves is said to interfere with the setting of these impression materials. The aim of this study is to evaluate the effect of handling techniques on the setting of vinyl polysiloxane impression putties using several types of gloves. The setting of these materials was evaluated by means of an elasticimeter.

Re-attachment of anterior fractured teeth: fracture strength using different materials.

This study compared the fracture strength of two different techniques (bonded only and buccal chamfer) and different material combinations used to reattach tooth fragments. An axial load applied to the buccal area fractured 110 sound permanent lower incisors. Fifty teeth were designated for the bonded only group (no additional preparation) and 50 teeth were designated for a buccal chamfer group.

A novel filling technique for packable composite resin in Class II restorations.

Unlabelled: The use of composite resin restorations in posterior teeth has increased considerably in the past few years. Specific composite resins for posterior teeth, as well as new operative techniques, have been developed to overcome some clinical difficulties. The present article describes a new technique to reconstitute the interproximal contour and contact of Class II restorations using a packable composite resin.

Microtensile bond strengths of one-bottle dentin adhesives.

Purpose: To investigate the in vitro performance of three one-bottle adhesives by measuring their dentin microtensile strength.

Materials And Methods: Extracted human molars had the dentin exposed on the occlusal surface. The teeth were randomly assigned to three dentin adhesives: Group 1 - Prime & Bond 2.

Re-attachment of anterior fractured teeth: fracture strength using different techniques.

Fracture of anterior teeth by trauma is a common problem in children and teenagers. Complex metal-ceramic crowns with considerable loss of remaining sound structure are no longer necessary due to adhesive techniques, such as composite restorations and re-attachment techniques. This study compared the fracture strength of sound and restored anterior teeth using a resin composite and four re-attachment techniques.