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My name is Dr. Sook-Bin Woo,
and I am Associate Professor
at the Harvard School
of Dental Medicine.
The topic for this lecture is Pigmented,
Brown or Black Lesions
of the Oral Cavity.
0:15
Pigmentations can occur
from either an exogenous sources,
which means outside the body,
or from an endogenous source,
which means inside the body.
The most common exogenous sources
of pigmentation are foods
that we eat every day,
so things like coffee and tea
that we drink
will often cause staining of the teeth.
Other very common exogenous pigments
that can cause lesions
in the oral cavity include amalgam,
graphite, medications that are taken,
ritual tattoos that occur
in some cultures in the world,
as well as imbibing heavy metals
for whatever reason.
Endogenous pigments
are those that are produced
by the cells within the body
and the two most common
are melanin pigment
produced by melanocytes,
which are often found on the skin
and also of coarse
within the oral epithelium
as well as blood-related pigments,
and these are related primarily
to the break down of red blood cells.
I just wanted to mention an interesting
chemical called homogentisic acid,
which is a phenolic acid
that is produced in the body
or accumulates in the body in patients
with alkaptonuria
which is poorly controlled,
and this causes very dark pigmentation
of many organs in the body.
But we're not going
to talk about that today.
It's just sort of an interesting
side note.
1:38
Let's start by talking a little bit
about extrinsic pigmentation
that refers to pigmentation
that lies on the surface
of the mucosa
or on the surfaces of teeth.
So these are exogenous
as well as extrinsic.
The most common are foods
that are pigmented,
so drinking lots of tea and coffee,
or smoking cigarettes,
chewing areca nut in all its forms,
and using chlorhexidine mouthwash
will often cause
a brownish black pigmentation
on the surfaces of the teeth.
The other very common sight
for extrinsic pigmentation
of exogenous origin
is the staining of the tongue,
and this gives rise
to a condition called a coated
or hairy tongue that is black or brown
usually because of pigment from foods,
whether this is a natural pigment
of the food
or whether the food has been dyed.
Pigmented tongue can also be caused
by bacterial products.
The tongue has many bacteria
on its surface
and the metabolites of these bacteria
are often sulfites,
and as we know,
most sulfites are black.
So very often the tongue
will have a black appearance
and that's called a black hairy tongue.
Patients who take
a lot of Pepto-Bismol
or bismuth subsalicylate for dyspepsia
will also often see
a black pigmentation on the tongue
because of the bismuth
which is a heavy metal.
