Denture teeth can be made of acrylic poly(methyl methacrylate) (PMMA) or composite resins. PMMA is a polymer - a material made the from joining of methyl methacrylate monomers. Properties of PMMA include resistance to abrasion, chemical stability and a high boiling point. (Jun Shen et al. 2011). However, weak flexure and impact strength of PMMA are of concern as they account for denture failure. (Bolayir G, Boztug A and Soygun K. 2013). Composite denture teeth are made of a three distinct phases - filler, matrix and coupling agents. Out of the types of composite teeth available, nano-filled composite teeth are preferred. Composite teeth have a PMMA coating around the tooth and a high content of filler particles. This gives them strength, higher resistance to forces than acrylic teeth and provides compete polymerization due to the PMMA coating. (Anusavice, K. J., Phillips, R. W., Shen, C., & Rawls, H. R, 2012). If the interface between the PMMA denture base and PMMA or composite teeth was weak, the denture will not be able to sustain occlusal forces, making the base-teeth interface, an entity of significance.
The contraction moulding method can be used to process an acrylic denture base. In this method, bite blocks are fabricated in the lab and sent to the clinic for patient trial. These are then received from the clinic and teeth are mounted onto the bite blocks. The wax is eliminated and teeth are pressurized and attached onto a gypsum mould. (McCabe and Walls. 2008.) Sodium alginate is applied onto the mould to act as a separator to prevent any monomer from the acrylic base seeping into the base and the mould. Acrylic PMMA is applied onto the mould and either heat-cured or auto-polymerized. Both of these curing methods form the...
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...an be seen that composite teeth form a high stability bond than PMMA teeth. This is due to the filler content allowing for low shrinkage, increased wear resistance and better cross-linkage with the base. In overall consensus the technique of heat-curing is believed to achieve significantly more polymer cross-linkage than that of self-curing the acrylic resin PMMA base - giving us a stronger base to teeth interface. It should be noted however that both techniques can be used for denture fabrication to achieve a desired result and it is up to the dentist and the technician to determine which one they prefer however, composite teeth bonded to a heat-cured PMMA base works best. Though the tooth and base by themselves may be strong, if the interface between them is not strong, this will result in the overall denture produced being weak independent of material selection.
Ceramics are most commonly used in dental applications as restorative materials for crowns, cements and dentures.
In recent years the discussion of whether dental amalgam is safe for use in filling caries has been a hot topic. In this project I will give an explanation of what dental amalgam is, mentioning and highlighting its beginnings in dentistry and how it became the most used restorative material to date. I will also be mentioning the reason there is so much controversy surrounding its use, and the basis for these questions. This will include information gathered from research collected by various scientists. Also mentioned will be the different restorative materials that came by due to the dental amalgam controversy.
Throughout the history of dental medicine dentist have searched for the perfect material to aid in the treatment of the most common problem in people’s mouths, cavities. The material would also be useful in fixing chipped and broken teeth. Dentist needed a material that was strong, relatively low costing, easy to apply, durable, and able to limit the growth of bacteria. In the early 19th century in France dentist found their wonder material and that material was amalgam. The dental amalgam is constructed of a mixture of mercury and at least one other metal such as zinc, copper, tin, or silver. The combinations of these metals are the foundation of what gives silver amalgams their strong make up and shiny metallic appearance.
The glass-infiltrated oxide ceramic framework consists of a porous pre-sin¬tered ceramic core that is subsequently infiltrated with a low-viscosity glass. The ceramic core can be fabricated in the dental lab either by slip casting ceramic powder slurry on a porous refractory die, or by milling out from a pre-fabricated CAD/ CAM ceramic block made by powder dry pressing9, 19, 21, 25. The oxide ceramic framework can be fabricated from different oxide materials and infiltrated by different glass materials. The available used oxide ceramics are aluminum oxide (Al2O3), magnesium aluminum oxide (MgAl2O4), and zirconium oxide (ZrO2). Glass-infiltrated Oxide Ceramics were first introduced in dentistry as In Ceram ® Alumina in 1989. It consists of 75
Throughout the history of dental medicine dentist have searched for the perfect material to aid in the treatment of the most common problem in people’s mouths, cavities. The material would also be useful in fixing chipped and broken teeth. Dentist needed a material that was strong, relatively low costing, easy to apply, durable, and able to limit the growth of bacteria. In the early 19th century in France dentist found their wonder material and that material was amalgam. The dental amalgam is constructed of a mixture of mercury and at least one other metal such as zinc, copper, tin, or silver. The combinations of these metals are the foundation of what gives silver amalgams their strong make up and shiny metallic appearance.
All-porcelain - Zirconia or aluminous materials are the most popular material choices for all-ceramic dental crowns. These materials provide a metal-free dental crown with a number of benefits. An aesthetic all-ceramic dental crown can be created with a thinner material because the accommodating metal core has been reduced or eliminated. The thinner option makes all-ceramic, or porcelain, dental crowns a treatment choice that is favored for areas with a limited amount of space. These crowns are more beautiful, but they do require care. These crowns are getting stronger all the time, and researchers are discovering new ways to use these crowns in high-impact areas of your
Suleiman, S.H. Steyern, P.V.V. (2013), Fracture strength of porcelain fused to metal crowns made of cast, milled or laser-sintered cobalt-chromium. Acta Odontologica Scandinavica, pp.1-10.
•Like an inlay, a white filling fills a hole in the tooth. Instead of porcelain, a composite resin is used. While this material is not as strong as porcelain, it is still durable.
When it comes to products that are being marketed, there are many different brands that are trying to be sold. It is important for the dentist to know which brand is best for the office. Research can be done online. They can compare the uses, advantages, and cost. The main use for composite resin dental materials is for restoring teeth that has been affected by decay and other damages (know your teeth, 2007). Composite resin is different from other dental materials because it is a white filling. It can be matched to the patient’s natural tooth color so the appearance is not an issue. Patients have the option of choosing between non esthetic and esthetic filling. That is why some patients prefer to have composite resin fillings than other dental materials. It is used for cosmetic purposes as well as fixing the decayed teeth. When the patient has a composite filling done, the dentist will place it on the tooth in layers. Most often, a light is used to harden the material. After the layers are in place and it is auto cured by the light, the dentist uses electronic instruments to reshape the tooth. It is important to shape it back as much as possible to the original tooth structure and anatomy....
There are two types of materials most commonly used for dental veneers: composite resin and porcelain. Both are or can be made by a dental technician in a lab and both are used to bond your veneers to your teeth. However porcelain is extremely brittle until it is bonded with the veneer and your teeth, then it is strong and durable like the composite resin.
The word ‘composite’ does not fully explain the wide range and varied compositions of materials that are categorized under it. This paper deals with some of the commonly used composites. Common materials such as metallic, ceramic and polymers consists of substances that can be classified as composites. The steel family, which is considered as the biggest group of material that is used in construction and complex engineering, is composed of composites that are made out of soft metallic matrix and hard ceramic components. [11] Such metallic composites could be shaped as a plate, needle, sphere or be polygonal. Polymeric composites are also found in a similar matrix model where one polymer forms the skeleton and another hard or soft polymer fills the matrix. A good example of this would be wood. Concrete is also a popular matrix composite where the Portland cement provides the matrix phase and the inner filling is made up of sands of different size. Scientists are now able to adjust the composition of these composites to suit the various needs. This adjustment is done by tweaking the microstructure of the materials by changing the state, shape, amount and distribution of the filling, which is also called as the reinforcing phase. Instead of restricting this tweaking process within a certain material class, the idea is being implementing in cross-material classes as well. Ceramics powder can be added to plastics to make hard and fireproof polymers. Ceramic powder when mixed with metals, gives cermets, which are used in tips of metal cutting tools. Another branch of the same idea is the blending of metal filaments, ceramic and polymer into one large bulk to form metal-matrix composites (MMCs), reinforced plastics (RP) and ceramic-matrix composites (CMCs). Such a radical idea of mixing all the three classes of materials has resulted in composites such as carbon fibre reinforced plastic (CFRP), glass reinforced plastic (GRP) and silicon-carbon-fibre-reinforced aluminium. Figure1 shows Comparison between conventional monolithic material and composite material. [17, 18,10and1
Tooth colored composites are a mixture of submicron glass filters and acrylic that form a tooth colored restoration. The main advantage of composites are seen when mentioning aesthetics. The color of the fillings can be matched to that of the tooth. This is why they are used in the anterior teeth. A unique feature of this filling is its ability to chemically bond to the tooth struct...
The choice of restorative material is considered to be one of the most important factors for the success and reliability of any restorative system. Composite resin gained popularity among clinicians due to its ease of handling, excellent esthetic and mechanical properties, and reported ability to reinforce weakened dental structure. (73) However, when a cavity preparation exceeds the recommended limits for the direct application of composite resins, indirect total- or partial-coverage restorations have been indicated.
Then, the teeth will be isolated with rubber dam (Hygienic Dental Dam, 2010). High and low volume saliva ejectors will be used additionally for suction of saliva and water from high speed hand piece. During preparation beveling of the enamel margins will be carried out for both groups to increase the surface area of enamel. The same set of burs and instruments will be used for preparation in both groups. Further, for the intervention group the enamel will be selectively etched for 15 seconds with 37% phosphoric acid followed by rinsing and drying of tooth. The one- step adhesive will then be applied to both enamel and dentin (Brady, 2013) with a micro tip applicator. Whereas, for the control group only the 1- step adhesive will be applied onto the prepared cavity. Furthermore, the adhesive will be cured with Mini LED light by Dentsply which has an intensity of 1250 mW/cm² (Adec, 2016). After curing of the bond, composite layering will be carried out by an incremental (0.5mm) placement of composite resin and cured with the same curing light to eliminate bias between the curing efficiency of different lights (Esmaeili, Safarcherati and Vaezi, 2014). Same set of instruments will be used for freehand shaping of composite between groups. A cellulose plastic matrix band and a wedge is used to contour the restoration interproximally (Chandra, S., Chandra, S. and Chandra, G. 2007). A microfilled composite resin [Filtek™ Z250 (3M ESPE)]
In some in vitro studies, fiber-reinforced composites (FRCs) have been also employed to reinforce cusp- replacing restorations. (69; 70; 71) Besides improving the strength of the restoration, results of these studies demonstrate that the incorporation of glass fibers into composite resin materials usually leads to more favorable fracture patterns above the CEJ because the fiber layer acts as a stress breaker and stops the crack propagation. Furthermore, and especially for endodontically treated teeth, this composite base reinforces cavity walls during the temporary phase.