REACTIVE & INFLAMMATORY WHITE LESIONS
LINEA ALBA (WHITE LINE)
Horizontal streak on the buccal mucosa at the level of the occlusal plane extending from the commissure to the posterior teeth
Common finding
Most likely associated with pressure, frictional irritation, or sucking trauma from the facial surfaces of the teeth
Present in about 13% of the population in one study.
Why White???
White colour is imparted due to any condition that increases the thickness of the epithelium thereby increasing the distance to the vascular bed.
TUBERCULOSIS
TB is a systemic, chronic granulomatous infectious disease with variable clinical presentation.
Etiology : Mycobacterium Tuberculosis, Acid-fast bacilli.
Myco.TB is aerobic, non-motile, rod shaped, non-sporing bacilli which is stained by Zeihl-Neelsen stain.
Most common infection, most are transient with few untoward sequelae.
Some are life threatening (e.g., Meningoccus, Diphtheria)
Severe, recurrent, disseminated or persistent lesions occur in Immunocompromised, organ transplant or AIDS.
Bacterial infections are diagnosed on Clinical grounds, supported by smears, culture, testing for immune responses (Serology) & examining for nucleic acids.
Antibacterial drugs can be effective therapy but, resistance can be a problem (e.g.. MRSA)
LEAD
The K-absorption edge for lead occurs at 88kev
so that the photons whose energies lie between 60 and 88 kev are much less attenuated than those between 88 and 110 kev
with a net result that more soft radiation than is desirable is transmitted and the high energy photons are excessively removed
PRINCIPLES IN CHOOSING A FILTER MATERIAL
The material chosen must attenuate principally by means of photoelectric effect in the photon energy range being dealt with in order to discriminate against low energy photons
The material must not have an absorption edge close to the energies of the photons that it is desired to use
The thickness of the material must not be too small – it should be uniform
Too thin might produce pin holes which might produce completely unfiltered beams
SELECTION CONSIDERATIONS
In order to prevent the shadows cast onto the film by the grid from interfering with visualization of diagnostic detail, certain principles must be followed:
the lead should be as thin as possible to be consistent with adequate absorption of scattered radiation. The thinner the lead, the narrower the shadow it will produce on the film and the less visible it will be to the eye.
Also, the thinner it is the less absorption of primary radiation will be in the grid. BUT it must be noted that adequate absorption of scattered radiation is the function of the grid and lead must be thick enough to provide this function.
PARALLEL GRIDS
When strips are not progressively angulated but are perpendicular to the surface of the grid, the grid is termed “parallel” .
USED in fluroscopy & mobile imaging.
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RADIOGRAPHIC ACCESSORIES
CONTENTS
GRIDS
FILTERS
COLLIMATORS
INTENSIFYING SCREENS
FILM HOLDERS
OTHER ACCESSORIES.
Nonodontogenic Cysts
NASOPALATINE DUCT CYST
Synonyms
Nasopalatine canal cyst
Incisive canal cyst
Nasopalatine cyst
Median palatine cyst
Median anterior maxillary cyst