The clinical manifestation of mild dental fluorosis is mostly characterised a snow flaking appearance that lack a clear border, opaque, white spots, narrow white lines following the perikymata or patches as the opacities may coalesce with an intact, hard and smooth enamel surface on most of the teeth. With increasing severity, the subsurface enamel, all along the tooth becomes more porous. Enamel may appear yellow/ brown discolouration and/ or many and pitted white-brown lesions that look like cavities. They are often described as "mottled teeth". Fluorosis does not cause discolouration to the enamel directly, as upon eruption into the mouth, affected permanent teeth are not discoloured yet. In dental enamel, fluorosis causes subsurface porosity or hypomineralizations, which extend toward the dentinal-enamel junction as the condition progresses and the affected teeth become more susceptible to staining. Due to diffusion of exogenous ions (e.g., iron and copper), stains develop into the increasingly and abnormally porous enamel. The differential diagnosis for this condition includes:

Turners hypoplasia (although this is usually more localized)
Enamel defects caused by an undiagnosed and untreated celiac disease. Some mild forms of amelogenesis imperfecta and enamel hypoplasia
Enamel defects caused by infection of a primary tooth predecessor
Dental caries: Fluorosis-resembling enamel defects are often misdiagnosed as dental caries. Dental trauma: Mechanical trauma to the primary tooth may cause disturbance to the maturation phase of enamel formation, which may result in enamel opacities on the permanent successors. Classification
The two main classification systems are described below. Others include the tooth surface fluorosis index (Horowitz et al.
Oslers nodes are painful, red, raised lesions found on the hands and feet. They are associated with a number of conditions, including infective endocarditis, and are caused by immune complex deposition. Their presence is one definition of Oslers sign. Causes
Oslers nodes result from the deposition of immune complexes. The resulting inflammatory response leads to swelling, redness, and pain that characterize these lesions. The nodes are commonly indicative of subacute bacterial endocarditis. 10–25% of endocarditis patients will have Oslers nodes. Other signs of endocarditis include Roths spots and Janeway lesions. The latter, which also occur on the palms and soles, can be differentiated from Oslers nodes because they are non-tender.Oslers nodes can also be seen in

Systemic lupus erythematosus
Marantic endocarditis
Disseminated gonococcal infection
Distal to infected arterial catheter

Etymology
Oslers nodes are named after Sir William Osler who described them in the early twentieth century. He described them as "ephemeral spots of a painful nodular erythema, chiefly in the skin of the hands and feet." == References ==