Evaluation of Mechanical Properties for Selected Dental Composite Resin Polymerized by Light Curing Technology at Different Thickness

The objectives of this study were to estimate the effect of the blue light cure unit on the compression force and hardness for composite resin nanoCeram at different thickness. The basic material used in this study was Ivoclar Vivadent Tetric N-Ceram Light Cured Hybrid restorative composite resin. The samples were cured by applying a (LED.F) unit Blue phase in a wavelength emission spectrum (494 NM) was used.60 disc-shaped specimens [9 mm diameter at (0.5, 1) mm thickness and 10 mm diameter at (1.5) mm thickness] were prepared using a stainless steel mold for hardness and compressive strength measurements. A composite resin was polymerized with an aid of a ( DC 5V/1A) lamp for (10, 20 and 30) sec .Three specimens were used for each group.The results were analyzed using (linear logarithmic, quadratic, linear and power) test.The different groups showed significant variability in relation, with a significant interaction between the groups.The result showed that the greater thickness more efficient for polymerization than small thickness and the long irradiation time more efficient for polymerization than short irradiation time, long irradiation time diffusion in deep portions of the sample convert to polymer and this provide good polymerization and then good mechanicalproperties.

Degree of Conversion of Light Cured Resin Cements Polymerized under Two Thicknesses of Different Lithium Silicate Ceramics

Objective: To show the consequence of two thicknesses of ceramic on the polymerization of resin cement light cured when three different lithium silicate ceramics were used. Materials and Methods: 42 ceramic slices were prepared from three types of ceramics, Emax CAD, Celtra Duo CAD and Vita suprinity CAD (n=14). They were further divided into two subgroups according to thicknesses into sub group thickness 0.5mm and sub group thickness 1mm (n=7). Teflon moulds were fabricated with specific dimensions, where the ceramic disc was placed followed by light cured resin cement Bisco choice 2 veneer and a glass slab with finger pressure applied. Curing with Ascent® PX LED light cure unit for 20 seconds took place, where the tip placed over the ceramic sample directly. Cement film was then separated from the ceramic disk and subjected to analysis by Fourier Transform Infrared Spectroscope. Uncured cement samples were also subjected to analysis. Results: Celtra DUO CAD ceramic showed higher degree of polymerization that of Emax and Vita suprinity while the difference between Emax and Suprinity on the degree of polymerization was not significant. Also, ceramic thicknesses had a significant effect on the degree of polymerization of the resin cement. Conclusion: Thickness of ceramics up to 1mm affects the polymerization of resin cement significantly.

Improving Composite Resin Performance Through Decreasing its Viscosity by Different Methods

The aim of this work was to present the different current methods of decreasing viscosity of resin composite materials such as (using flowable composites, lowering the viscosity of the monomer mixture, heating composites and applying sonic vibration) and furnish dentists with a basis that can provide criteria for choosing one or another to suit their therapeutic requirements. The four discussed methods proved that lowering composite viscosity improves its handling and facilitates its application to cavities with complicated forms, decreasing time for procedure and improving marginal adaptation. Other properties improved by decreasing composite resin viscosity were controversial between the four methods and affected by other factors such as composite brand and light cure unit.

Essentials of minimally invasive operative dentistry

All members of the oral healthcare team have a part to play in patient management, and the team is comprised of the lead dentist (plus other colleagues in the dental practice), the dental nurse, hygienist, receptionist, laboratory technician, and possibly a dental therapist. In the UK, registered dental nurses can take further qualifications in teaching, oral health education, and radiography, and can specialize in other aspects of dentistry, including orthodontics, oral surgery, sedation, and special care. If the dentist wishes to have a second specialist opinion regarding a difficult diagnosis, formulating a care plan or even executing it, they may refer the patient to a specialist dentist working in another practice, or to a hospital-based consultant specialist in restorative dentistry. These specialists have undergone further postgraduate clinical and academic training and gained qualifications enabling them to be registered as specialists with the General Dental Council (GDC) in the UK in their specific trained fields (e.g. endodontics, periodontics, prosthodontics), or have further specialist training in restorative dentistry. The lead dentist will act as a central hub in the coordinating wheel of patient management, possibly outsourcing different aspects of work to relevant specialist colleagues, as spokes of that wheel. This is the clinical environment in which patients are diagnosed and treated. This room has traditionally been known as the ‘dental surgery’, but a more appropriate modern description might be the ‘dental clinic’, as much of the more holistic care offered to patients within its four walls will be non-surgical in the first instance. The operator and nurse must work closely together. To be successful, each must build up an understanding of how the other works. The clinic consists of a dental operating chair with an attached or mobile bracket table carrying the rotary instruments and 3-1 air/water syringe (and possibly the light-cure unit and ultrasonic scaler), work surfaces (which should be as clutter-free as possible for good-quality infection control; see later), cupboards for storage, and two sinks, one for normal hand washing and another for decontaminating soiled instruments prior to sterilization. Often the surgery will also house an X-ray unit for taking intra-oral radiographs. Most clinics are designed to accommodate right-handed practitioners, in terms of the location of many of the instruments and controls.