Dentistry
for the 21st Century is about preserving as much natural
tooth tissue as possible. You have been used to these
structures since they erupted into your mouth, and
teeth are important in maintaining the supporting
bone contours, as well as providing surfaces to function
with. By this I mean speech, biting and chewing. Teeth
in one jaw also offer support to those in the opposing
jaw, to maintain their position in the dental arch.
Research has also indicated that the shape and position
of your teeth also push food material over the gum
tissue in a very special way, massaging and cleaning
the tissue as you eat.
There
are several occasions where tooth extraction is necessary,
and these are decay, infection, fracture and severe
crowding.
Tooth Decay
Dental decay is caused by the destruction of the outer
enamel surface of the tooth structure, allowing bacteria
to penetrate into the less dense dentine tooth body.
As the process of decay progresses, the advancing
wave of bacterial products begin to irritate, then
kill the nerve tissue. Once the nerve tissue dies,
depending on the bulk of the tooth remaining, it may
be possible to save it by root canal treatment, or
if the destruction is too great, accompanied with
infection in the supporting bone tissue, removal or
extraction becomes the reluctant treatment of choice.
There
have been many theories why dental decay begins and
progresses, but it is generally accepted that the
following processes occur.
Decay
occurs at sites where bacteria accumulate and convert
sugars to acid by-products of living and reproduction.
These acids dissolve the mineral components in enamel,
and leave rough areas, which may be stained. These
'early lesions' can remineralise and 'heal' if recognised
and you, the patient, become more motivated and efficient
in your cleaning routines.
As
further minerals are dissolved out of the decaying
area, more bacteria collect in the rough area and
the lesion penetrates through into the dentine. Dentine
is a living tissue. If you can imagine a tooth structure
as follows, then you will understand of the process
of decay better.
The
centre of the tooth is soft tissue, comprising nerve
and blood supply tissue. The outer surface of the
nerve tissue is similar, to you scholars, to a Medusa's
head, with millions of fine 'hairs' that are minute
nerve ends. Each 'hair' runs up inside a single small
tube with in the dentine. So if you can imagine the
dentine as an enormous bundle of straws centred around
a ball ( the nerve tissue), these hairs would run
up inside each straw. Covering the outer ends of the
straw tubes is the enamel which is a very hard crystalline
material. This outer surface is the surface that takes
all the abuse of the food we eat, fluids we drink,
and trauma when we bite and chew, or get hit in the
mouth during sports, brawls and accidents. The reason
that our teeth do not fracture all fall apart after
each knock is their unique design. The dentine is
50% water, and the tubular construction when wet with
nerve fluids keeps this material flexible, and able
to absorb energy. So, you may well have many fracture
lines that you can see in your own teeth, but the
properties of the dentine bind the whole tooth together
and keep it intact and functional. The analogy that
I use to my Patients is a grass leaf. When wet, it
can be folded, knotted and woven. These processes
can be reversed, and the leaf returned to a single
leaf, usually without breakage. But once the grass
leaf dries to become hay, it is fragile and brittle.
If you attempted to fold, knot or weave it is this
dried state, it would probably break or fracture.
Nature has many other examples of this.
Now
once the acids and bacterial by-products gain entry
into the dentine, the rate of penetration and destruction
is increased by its unique 'straw-like' construction.
Depending on where the decay area started in the tooth,
and the shape of the advancing decay, structural failure
of portions of the tooth, or the whole crown, can
occur. Unless this stage is quickly stabilised, the
nerve tissue will die, leading ultimately to infection
within the supporting bone tissue.
Infection
in the bone tissue is not a reason per se to remove
the tooth, as many patients that we see have teeth
where the nerve tissue has been removed and the tooth
restored once the infection has been eliminated. This
process is called root canal treatment (Click
here for more details. )
Click
here for more reasons for extraction