Continued from Part 1
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Implant is the endosteal (within bone) material that is placed within the bone during stage 1 dental implant surgery. It is either titanium or titanium alloy, with or without hydroxyapatite coating. Continue reading
Amelogenesis imperfecta is a tooth development disorder in which the teeth are covered with thin, abnormally formed enamel, occasionally in conjunction with other dental, oral and extraoral tissues.. Enamel is composed mostly of mineral, which is formed and regulated by the proteins in it. Amelogenesis imperfecta is due to the malfunction of the proteins in the enamel: ameloblastin, enamelin, tuftelin and amelogenin. Continue reading
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Dental implants are now increasingly used to attach crowns, bridges or dentures by anchorage to bone. Despite its benefits, placement of implants requires careful patient selection and treatment planning to ensure long-term success of implants. Continue reading
During mastication, four muscles of mastication (or musculi masticatorii) are responsible for adduction and lateral motion of the jaw. Other muscles, usually associated with the hyoid such as the sternohyomastoid, are responsible for opening the jaw. Continue reading
Hemoglobin is the protein found in red blood cells in our blood that is responsible for carrying oxygen to all the different parts of out body. Hemoglobin is made up of 4 protein chains, ie 2 beta globin and 2 alpha globin. Thalassemia occurs when there is decrease in production or absence of production of either of these chains, leading to malfunctioning hemoglobins that are unable to carry oxygen. This then leads to anemia.
Thalassemia is thus classified by the type of globin that is affected: either alpha thalassemia or beta thalassemia, and each is classified according to the severity of which one is affected, ie either thalassemia major or thalassemia minor. People with thalassemia minor, either alpha or beta, may not have any symptoms. Continue reading
When a practitioner is faced with enforced extraction of a primary tooth it is often a dilemma whether to merely remove the unsaveable tooth , to extract a contralateral tooth from the same arch (balance), or to extract a tooth from the opposing arch (compensation). The following guidelines are intended to assist in making such a decision and to minimise the effect of space loss on the developing dentition. There have been no properly controlled prospective randomised studies into the consequences of early loss of primary teeth, probably due to the difficulty of recruiting subjects for such studies and the need to follow them for up to 10 years. The recommendations given are therefore based partly upon current clinical opinion, although this is supported where possible by the best available research data. There is a need for more research in the area. Continue reading
The disc is thick all around its rim, and thin in the centre. From anterior to posterior it shows – anterior extension, thick anterior band (2.0mm thick), intermediate thin zone (1.0 mm thick), thick posterior band (3.0 mm thick) and posterior most bilaminar region (Dubrul, 1996; Williams et al, 1999). The disc is attached all around the joint capsule except the strong straps those fix the disc directly to the medial and lateral condylar poles which ensures that the disc and condyle move together in protraction and retraction (Choukas and Sicher, 1960; Williams et al, 1999). The anterior extension of the disc is attached to fibrous capsule superiorly and inferiorly and through that to temporal bone and the mandibular neck respectively. In between it gives insertion to lateral pterygoid muscle where the fibrous capsule is lacking and synovial membrane is supported only by loose areolar tissue. In the opinion of Kreutziger and Mahan (1975), this deficiency anteriorly is the weak point since there is no fibrous resistance to hypertranslation. Apart from lateral pterygoid, anteromedially, there are attached some fibres of masseter and temporalis laterally. Although more than one muscle is inserted into the disc, majority of the interest has been focussed on lateral pterygoid, whose deep position, unfortunately makes it difficult to investigate under natural conditions (Moore). Continue reading
The smooth slippery, pressure bearing tissue carpeting, the surfaces of the bones varies in thickness across different articular areas. It is essentially a bed of tough collagen fibres bound by special glycoproteins. On the condyle, the tissue is thickest in anteroposterior direction and thickness is greater medially (average measurements 0.37 mm laterally and 0.48 mm medially). On temporal component, it is thickest along articular eminence and preglenoid plane. The thickness is less medially (0.49 mm and 0.36 mm for eminence and plane respectively laterally and 0.45 mm and 0.34 mm medially). In the depth of the mandibular fossa the thickness of periosteum is merely 0.07 mm. Continue reading
A stroke, also called cerebrovascular accident (CVA), is a condition whereby the blood supply to the brain is blocked leading to lack of oxygen supply to the brain cells. Brain cells can die when the oxygen supply is cut off for even a few seconds. This leads to loss of function of parts of the body controlled by that region of the brain. If the right side of the brain is affected, the left part of the body will be affected and vice versa.
There are two types of stroke based on their etiology:
Hemorrhagic stroke
Temporomandibular joint also known as jaw joint or mandibular joint is an ellipsoid variety of synovial joints, right and left joints forming a bicondylar articulation (Williams et al, 1999). The common features of synovial joints exhibited by this joint include a fibrous capsule, synovial membrane et fluid and tough adjacent ligaments etc. However the features which differentiate and make it unique in itself are: Continue reading