The decrease in bond strength is because the caries-affected and caries-infected dentin is more porous, contain more water, and thicker hybrid layer, which is not necessarily well-infiltrated, despite the bonding strategy. This lower bond strength that occur in caries-affected dentin is due to structural changes caused by caries progression. Caries will reduce the mineral content and crystallinity of the hydroxyapatite, and alter the secondary structure of collagen. Also, decreased distribution of sound collagen fibrils and proteoglycans. All of these structural changes will result in a substrate that has lower mechanical properties, which will have great impact on the bond strength.
They are placed over the tooth in order to restore the size and shape of the tooth and also to improve its appearance.] Main objective of dental crowns is to protect a weak tooth from ... ... middle of paper ... ...lap technique Two-flap technique Schweckendiek technique and Von Langenbeck technique etc. Congenital craniofacial deformities [Craniofacial deformities are very common disorders. The surgery for craniofacial defects is a broad spectrum of reconstructive procedures of the face and cranium. Craniofacial surgery is a sub-speciality of oral and maxillofacial surgery and plastic surgery] In the early times, these kinds of abnormalities are considered to be untreatable.
It affects the mandible more than the maxilla that will affect the facial appearance and substantial modifications in the soft-tissue profile (e.g protrusion of the mandible,lip and chin). Bone loss will accelerate, as long as the patient is not wearing a denture, and if the patient wears any poorly fitting soft tissue prosthesis. Teeth loss leads to remodeling and resorption of the surrounding alveolar bone, thus leading to atrophic edentulous ridges. Gender, hormones, metabolism, parafunction and ill-fitting dentures are considered as factors that increase the amount of bone
Acrylic PMMA is applied onto the mould and either heat-cured or auto-polymerized. Both of these curing methods form the... ... middle of paper ... ...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.
• Due to the addition of water, entrapped air is decreased which reduces the dustiness as compared to dry granulation. • Prevents the segregation of the components by forming a homogeneous powder. • Dissolution rate of hydrophobic drugs is improved due to certain binders and solvents. Disadvantages of wet granulation are: • This method is expensive due to cost of time, equipment, energy and space requirements as compared to direct compression. • Increased number of processing units increases the chance of problems such as difficulty in controlling or validation.
This composition and formulation possessed a higher molecular weight and therefore better mechanical properties and reduced polymerization shrinkage, the newer polymer offered potential for much greater applications that included anterior and posterior composite resin restorations, indirect inlays/onlays, pit and fissure sealants and more wear resistant denture teeth. Dental composites are widely used for crown preparation and in-lays formation. These materials are similar to those used in direct fillings and are tooth-colored. Their strength and durability is not as high as porcelain or metal restorations and they are more
More time should be allowed to dissolve the tablets as if they are not dissolved colour changes are harder to identify during the titration and also the results are less accurate. The acid used should also be more concentrated as a 0.5mol or 0.3mol would mean a smaller amount of acid would be required. Conclusion From the results and discussion it is clear that the Rennie tablet is more effective at neutralizing acid and could relieve indigestion better. The Rennie tablets are also much more cost effective as they require fewer dosages and you get double the amount of tablets for only an extra 30c. The hypothesis was correct as the Rennie tablet had the higher basic content and was thus more effective at neutralizing acid.
In conclusion, it has been proved that the factors that largely affect composite resin shrinkage are cavity preparation size and configuration. As the light passes through composite and tooth material, light intensity attenuates. Hence, it is best to place 2mm increments of composite resin to allow for maximum polymerisation. Even though there are different curing modes of light curing units, the selected composite affects shrinkage more that the method of curing. A composite resin that does not allow shrinkage needs to be developed in order to improve marginal integrity.
An Introduction to Tumescent Liposculpture Tumescent liposculpture is a recent liposculpture procedure that is bringing loads of excitement to the table. Unlike previous fat dissolving techniques, such as liposuction, liposculpture does a better job of sculpting to the body to make the appearance you wish for. Liposculpture doesn't just dissolve the fat and hope the skin heals correctly to design the look you wish for. Instead, careful operating and planning aid to adjust the problematic region into an appearance you have always wished for. Tumescent liposculpture is just another procedure that refines the overall value of liposculpture.
Within this experiment I looked at concentration and surface area - although temperature may have still played a part in the final results. The concentration of a solution is how strong the solution is. In this experiment, the stronger acid contains more acid particles and less water particles than a weaker acid. Increasing the concentration of the solution leads to more collisions so the rate of the reaction goes up. In a less concentrated solution (diluted hydrochloric acid), the number of collisions is long so the rate of reaction is slower.