Dental abscess – causes, symptoms, diagnosis, treatment, pathology

Dental abscess – causes, symptoms, diagnosis, treatment, pathology


On our Youtube channel, you’ll find a limited
selection of pathology and patient videos. With Osmosis Prime, you’ll get access to over
700 videos including complete coverage of pathology and physiology and a growing collection
of pharmacology and clinical reasoning topics. Try it free today. Everyone who has ever had a pimple has had
an abscess, even though they’re tiny, they’re still abscesses. An abscess forms when normal tissue, like
the gingiva or gums and teeth for example, is split apart and that new space is invaded
by nearby pathogens like bacteria. In a healthy mouth, normal or commensal bacteria
thrive but don’t cause disease. However, any cut or break in the mucosa is
an invitation for bacteria to dive in and multiply, causing an infection. When that happens, the immune system typically
responds and a battle ensues with the result being pus – a mixture of bacteria, immune
cells, and dead tissue. So, in response to an injury, cells release
small chemicals called cytokines, like tumor necrosis factor, interleukin-1, interleukin-6,
interleukin-8, and interleukin-17, and these attract nearby immune cells. It’s kinda like like yelling for help and
being heard by the nearby police. In addition, the cytokines also dilate nearby
capillaries and make them leaky – which brings more blood to the site, and allows immune
cells that do show up, to easily slip out of the blood and into the tissue. The first immune cells at the scene are neutrophils,
and they release chemicals and enzymes that kill themselves and the bacteria they swallow
up, creating a pool of dead bacteria and cells. This is a specific type of acute inflammatory
response called suppurative inflammation, which simply means that pus is created in
the process. From a macroscopic view, this is sometimes
referred to a liquefactive necrosis, because the area of dead tissue turns to liquid. Initially the dead tissue is intermixed with
healthy tissue, but over time it can coalesce into a single area. And around this pool of pus, a wall of fibrinogen
– starts to harden into a barrier. Occasionally sheets of fibrin form septations,
creating loculations or pockets of pus within the abscess itself…kinda like an abscess
within an abscess… Even though the pus is largely dead material,
there are still plenty of live bacteria within the pus, which makes it highly infectious
if it gets spread from one place to another. There are a few different types of dental
abscesses. The first one is called a periapical abscess,
and it’s located at the apical foramen of the tooth. A periapical abscess begins when bacteria
gain entry into the dental pulp of the tooth through an opening caused by dental caries
or from trauma. The inflammation then spreads and causes necrosis
or tissue death throughout the entire length of the dental pulp. And if it goes on without treatment – like
a root canal, then the infection ultimately reaches the apical foramen of the tooth. Subsequently, the infection reaches the periapical
tissues and at that point, it’s considered apical periodontitis, which is inflammation
of the periapical tissues which secure the tooth in its socket. The infection usually develops into an abscess
as the pus coalesces, and it can involve nearby structures like the alveolar bone and adjacent
teeth. Sometimes periapical abscesses become quiescent,
meaning that they don’t grow much but the bacteria remain alive within the abscess cavity. In that situation, it’s called chronic inflammation,
and it’s where a periapical granuloma forms from this walled-off area. In fact, technically, the term “granuloma”
is a misnomer in this case since these lesions don’t look like normal granulomas under
a microscope. During this stage where there’s a stalemate
between the infection and the immune system, if the infection gains the upper hand, then
it’s called an acute apical abscess. Another type of dental abscess is a periodontal
abscess, and that involves both the periodontal structures and the gingiva. Typically, a periodontal abscess occurs when
there’s a pre existing periodontal pocket, perhaps from a deep plaque collection or from
a medical procedure. Bacteria get into the periodontal pocket,
and multiply, leading to an infection and an abscess. Next, there’s the gingival abscess, which
is where the abscess only involves the gingiva next to the bone, called the marginal or interdental
gingiva, while sparing the periodontal structures. This usually occurs when food, plaque, or
another foreign object gets stuck in the gingival sulcus, providing a protected place for bacterial
growth. Finally, there’s a pericoronal abscess. This occurs when a tooth does not erupt completely,
leaving a flap of gingival tissue over the top of the crown. When food or another foreign object gets deeply
trapped between the flap of gingival tissue and the top of the tooth, an abscess can form. Generally speaking, dental abscesses contain
a mix of different bacteria. Some are facultative anaerobes, which means
that the bacteria prefer to make energy using oxygen but can also survive without oxygen,
like Streptococcus anginosis group and the viridans group of Streptococci. Others are obligate anaerobes, which means
that the bacteria thrive only in the absence of oxygen, like Fusobacterium and Prevotella
groups. Symptoms of dental abscesses mainly include
local pain and swelling, as well as generalized symptoms like fever and malaise. Dental abscesses can cause affected teeth
to loosen and they can sometimes create a fistula to the surface, where the tissue overlying
the abscess breaks down, allowing it to drain out by itself. This can either be within the mouth, or out
through another surface like the cheek. The abscesses can also erode into nearby structures
such as the nasal sinuses – causing sinusitis, the floor of the mouth, or even into the neck. Diagnosing a dental abscess is usually done
by feeling for areas of tenderness and fluctuance, and imaging studies like x-rays or a CT scan
can be done to determine the exact location and size. Generally speaking, infections are treated
with antibiotics, but in order for antibiotics to work, they need to first reach the bacteria,
and that’s usually done through the bloodstream. Since abscesses do not have blood vessels
inside of them, the antibiotics can only diffuse into an abscess and that’s not very effective
especially when dealing with a large abscess; you could imagine it getting to bacteria close
to the edges, but there’s no way it’s getting to the bacteria in the middle. That’s why the most important treatment
for an abscess is incision and drainage – in other words, cutting it open and removing
the pus. This is typically followed by frequent saltwater
rinses, pain relieving medications, and regular check-ups. For periapical abscess, a root canal treatment
or extraction has to be performed on the offending tooth to get rid of the infection that cannot
be reached by an incision and drainage or antibiotic treatment. Sometimes, antibiotics are used even after
drainage to make sure that there are no additional bacteria lingering around. All right, as a quick recap… Dental abscesses are a mix of immune cells,
pathogens such as bacteria like viridans group Streptococcus, and dead tissue. Common types include periapical, periodontal,
gingival, and pericoronal abscesses. Because there’s no blood supply to the middle
of an abscess to deliver antibiotics, it usually needs to be cut open so that the pus can drain
out. For periapical abscess, a root canal treatment
or extraction has to be performed on the offending tooth.

30 Comments

Leave a Reply

Your email address will not be published. Required fields are marked *