Validation of clinically related aging models based on enamel wear.

Purpose: Physiological and erosive wear reported in clinical studies were reviewed, and in vitro aging models were developed to simulate and compare the effect of aging on human teeth with the review data obtained from clinical studies.

Methods: A review of clinical studies and randomized clinical trials that quantify enamel wear was performed in the PubMed database. The first in vitro analysis evaluated the effect of mechanical chewing simulation only.

Chemical and Ultrastructural Characterization of Dentin Treated with Remineralizing Dentifrices.

The aim of this study is to investigate dentin chemical and ultrastructural changes upon exposure to remineralizing dentifrices. Dentin disks were obtained from permanent human molars and treated for 7 days with the dentifrices: (1) C group-control (no dentifrice); (2) S group-Sensodyne Repair & Protect; (3) D group-Dentalclean Daily Regenerating Gel; and (4) DB group-D group + Dentalclean regenerating booster. Afterwards, samples were submitted to an additional 7 days of toothbrushing associated with daily acidic challenge.

Postinsertion adjustment appointments and their association with cast removable partial denture survival.

Statement Of Problem: Successful outcomes with cast removable partial dentures (RPDs) are dependent on adequate fabrication and adjustments at the delivery appointment. Evaluation of the number and frequency of postinsertion follow-up appointments helps determine whether the prosthesis continues to fit comfortably and whether function and esthetics continue to be satisfactory. Reports on the number of appointments and frequency and type of adjustments required for RPDs following insertion are sparse.

Effect of artificial aging on optical properties and crystalline structure of high-translucency zirconia.

Purpose: To investigate the effect of different in vitro aging protocols on the optical properties and crystalline structure of high-translucency (HT) zirconia.

Materials And Methods: Thirty-six specimens of HT and extra-high translucency (XT) zirconia were divided into three groups: control (CO)-no treatment; hydrothermal aging (HA)-autoclave aging for 12.5 h at 134°C, 2 bar; clinically related aging (CRA)-aging in the chewing simulator for 1.

Effect of Simulated Gastric Acid on the Interface Between Zirconia and Resin Cement.

Purpose: To evaluate the effect of simulated gastric acid solution (SGAS) and resin cement composition on the shear bond strength (SBS) of zirconia-based materials with different levels of translucency to composite resin.

Materials And Methods: A total of 40 medium-opacity (MO; 3Y-TZP) and 40 medium-translucency (MT; 4Y-PSZ) zirconia slabs were distributed into four groups according to the composition of the resin luting system (MDP free or with MDP [primer + Panavia V5]) and storage method (distilled water or SGAS [5% hydrochloric acid]). Composite resin cylinders were cemented on the zirconia surface and stored for 91 hours.

The effect of accelerated aging on crystalline structures and optical properties of different monolithic zirconia: A qualitative systematic review.

Objective: This study aimed to systematically review the literature related to the impact of low temperature degradation (LTD) on the crystalline structures and optical properties of different types of dental monolithic zirconia materials.

Methods: The systemic review was performed based on the PRISMA statement. In vitro studies investigating the effect of accelerated aging in autoclave (2 bar pressure 134°C - ISO standard 13356-2008) on the crystalline structure and/or optical properties of Yttria-partially stabilized zirconia (Y-PSZ) were included.

Improving effectiveness of dental students' feedback and course evaluation.

Dental students providing feedback about a course they take, in a timely manner, benefits not only teachers, but also indirectly the students themselves, especially if given with confidence in a constructive manner. Therefore, the aim of this study was to train students on how to give feedback, to ask them to provide feedback before and after the instructions were given, and analyze the change in their responses. Participants were students who attended the second-year preclinical course in prosthodontics.

Irradiation therapy and chewing simulation: effect on zirconia and human enamel.

Purpose: Ionizing radiation therapy (RT) is the main option for head and neck cancer treatment, but it is associated with multiple side effects. This study aimed to evaluate the effect of RT associated with chewing simulation on the surface of human enamel and Yttria-partially stabilized zirconia (Y-TZP).

Methods: Maxillary premolar cusps and Y-TZP slabs were divided in 7 experimental groups: CO: no RT (control); EZ groups had irradiation applied to both, enamel and zirconia samples (simulating restoration prior to RT); E groups had irradiation applied to enamel only (simulating restoration after RT).

Effect of ionizing radiation and chewing simulation on human enamel and zirconia.

Purpose: To evaluate the effect of ionizing irradiation on human enamel and zirconia after chewing simulation.

Methods: Twenty enamel and twenty translucent Yttria-stabilized zirconia (Y-PSZ) specimens were divided in 4 groups: Co (control) - no irradiation on enamel cusps/opposing zirconia slabs; E70 - irradiated (70 Gray) enamel cusps/opposing irradiated enamel slabs; Z70 - irradiated zirconia cusps/opposing irradiated zirconia slabs; EZ70 - irradiated enamel cusps/opposing irradiated zirconia slabs. Cusps were abraded against slabs in a chewing simulator (CS - one million cycles, 80 N, artificial saliva, 37˚C).

Effect of cleaning protocol on silica deposition and silica-mediated bonding to Y-TZP.

Objectives: To evaluate the effect of cleaning methods on the deposition of silica on yttria-stabilized zirconium dioxide (Y-TZP) surface and on the silane-silica mediated bond strength between Y-TZP and resin cement.

Methods: Y-TZP slabs were air-abraded with 30μm silica-coated alumina particles and distributed in three groups: no cleaning, cleaning with a stream of oil-free air/water spray for 5s and cleaning with an ultrasonic bath in water for 10min. The distribution of Si on the Y-TZP surfaces was recorded using energy dispersive spectroscopy (EDS).