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Dental caries disease also called tooth decay
Refers a demineralization or weakening of the teeth and the end result of caries diseases. It carries the lesion
An advanced caries lesion can progress to the point where the tooth surface forms a cavitation or a hole?
Which is the physical evidence of tooth breakdown?
Let's start by building a model of a tooth and its surrounding structures in the mouth the bone beneath
The bottom row of teeth is the mandible and the bone above the top row of teeth is the maxilla
Both bones have an alveolus or socket for each tooth
The socket is lined on the inside by a para Donald ligament
protecting the alveolus on the outside is a layer of soft supportive tissue called the gingiva or gums that
Sits on the top of the bone and covers the root surface from the bone to the cementoenamel junction
Where the cementum in the UNAM will come together
The tooth itself can be roughly divided into a few parts. The first part is the root and it sits within the alveolus
the root is covered by cementum, which is a bone like substance that the para donald ligaments fiber is attached to
Next there's the neck which is the transition between the root portion covered by bone in the crown
The crown is the visible part of the tooth that protrudes from the gingiva, and it's covered in enamel
Which has such a high mineral content that it's the hardest substance in the human body
When the teeth are developing enamel is made before the tooth erupts into the mouth by a group of cells called the ameloblasts
That dye wants the tooth erupts
Meaning that the teeth lose the ability to make more enamel forever
Now let's fill the tooth in from the inside out
Blood vessels and nerves come from the jaw bones and enter the center of the root through a narrow passage
Called the apical foramen
From there. They enter the soft center of the tooth called the pulp. Will they provide nutrition in sensation?
The outer wall of the pulp has Edano blasts which are cells that secrete a bone like substance called dentin
Which is filled with proteins and minerals
The Adana blasts have long processes or arms that lay within tiny tubules in the dentin
Kind of like an octopus sticking its arms through a block of cement
These tubules are important for sensory nerves as well, which use them to travel through the dentin from the pulp to the dentin enamel Junction
Finally there's saliva, which is secreted from several glands in the mouth
Saliva has bicarbonate ions, which helps to neutralize acid in the mouth as those glycoproteins like mucin that thickens the saliva
Saliva also has calcium and phosphate which serve as a replacement minerals to help remineralize the tooth surface
So when it comes to dental caries
There's a tug of war between the pathogenic factors that promote demineralization of the tooth and protective factors that promote re mineralization of the tooth
Normally, there's a layer called the pellicle that covers the tooth and bacteria in the mouth like viridans group streptococci
settle on that pellicle layer
These bacteria are called early colonizers and they attach to the surfaces using bacterial surface proteins called adhesions
because they're on the pellicle of the teeth these bacteria come into contact with sucrose which
Is a sugar found in various foods and drinks including table sugar?
Sucrose has a glucose molecule bound to a fructose molecule
so the bacteria use an enzyme called glucose sil transferase to cut the bond between them and
Use the fructose for energy and add glucose to a growing chain of glucose molecules called the glucan
Who cans allow the bacteria to attach firmly to the surface of the tooth and form dental plaque which is a sticky collection of bacterial
Proteins from saliva and dead cells from the lining of the mouth
Individual bacteria multiply and form a lot of small micro colonies that coalesce which creates a layer of dental plaque
What is the type of biofilm?
Compared to a micro colony the bacteria in a biofilm communicate with each other via chemical signaling and together
they create a complex system where some bacteria work on tunneling between the micro colonies and to the surface in order to bring in a
steady supply of food as
An analogy if bacteria were ants than a micro colony would be a tiny group of ants each doing its own thing
Whereas a biofilm would be an ant farm with complex tunnels in rooms and each ant carrying out a specialized task
So typically dental plaque can form on the surface of teeth
But if the pH of the local environment around the tooth surface remains above about 5.5
enamel will not demineralize
One factor that tips the balance towards caries progression is having less bicarbonate rich saliva, which can result from conditions like Sjogren's syndrome
radiation treatment for cancer gastric reflux or as a side effect of a medication or recreational drugs a
Key factor that contributes to tooth demineralization is sugar
some bacteria ferment sucrose and that produces lactic acid as a byproduct in
Addition acidic foods and drinks can also cause a pH in the mouth to lower
So a drink that has lots of sugar and lots of acid like soda which has a pH of around three
Can damage the teeth in two ways?
The bacterial population in the mouth is diverse and if the pH in the mouth starts to decrease it alters the balance of power
bacteria that thrive in a low PH like mutants streptococcus e in lactobacillus start to dominate
as
Dental plaque grows thicker the amount of oxygen near the enamel surface starts to fall
That makes the environment on the enamel surface favorable for facultative anaerobic bacteria
Which can metabolize sugars with and without oxygen present if?
Sucrose is metabolized anaerobically or without oxygen
Lactic acid starts to build up and it can quickly lower the pH on the enamel surface to below 5.5
Once the environment becomes that acidic
calcium and phosphate in the enamel start to dissolve into the fluid filled diffusion channels between the enamel crystals and
That starts the process of demineralization
Every time sugar enters the mouth the bacteria are able to produce more acid and this destruction in the subsurface
Continues until the surface gets so thin that it collapses like walking on thin ice
Intact enamel keeps bacteria out of the dentin because they do not fit through the enamel diffusion channels
However, if deep mineralization is allowed to continue the enamel surface will cavitate to expose the dentin which will allow bacteria to enter the dentin
once bacteria are in the dentin it's called infected dentin and usually requires a restoration or filling if
Destruction continues into the dentin layer, then the caries lesion enlarges towards the pulp
Eventually the bacteria penetrate into the pulp causing irritation and damage to the nerves
That's the stage when individuals usually experience pain
Although pain can also happen when the caries lesion involves the dentin layer since sensory nerve fibers travel through tubules in the dentin
Eventually bacteria travel down into the root canal space and fill the entire inside of the tooth
it's worth mentioning that formation of a carious lesion doesn't have to start with the enamel of the crown if
The gingiva recedes or plaque forms between the gingiva and the root
Bacteria and acids have direct access to the cementum which is much softer than enamel and dissolves more quickly
The demineralization of cementum and dentin can happen in a pH range of 6.2 to 6.8
Symptoms of dental caries include tooth pain and sensitivity
Especially when chewing or drinking something. That's or hot or sweet
If the process continues it can eventually lead to a root canal procedure or even losing a tooth
Diagnosis is usually made based on symptoms and looking for areas of discoloration or roughness
Tenderness or inflammation in the mouth as well as using dental radiographs
It's always ideal to prevent a caries lesion from forming in the first place and it starts with a risk assessment for identifying
individuals at high risk of caries
That includes individuals that have had a prior or current carries lesion have problems with saliva production
has specific abnormal levels of acid forming bacteria like mutant streptococcus II and lactobacillus in their mouths and
Those that have poor dietary habits like frequent snacking as well as a high sugar diet
so treatment of dental caries disease depends on the level of risk more specifically reducing the pathogenic risk factors like
antibacterial rinses to get rid of bacteria and
increasing protective factors like products that mimic saliva
In addition brushing and flossing are useful because they physically remove dental plaque as well as deliver fluoride to the teeth to help with
Remineralisation products that have fluoride can help remineralize spots where enamel is lost. It's hard minerals
If the enamel surface is intact, then the caries lesion can be treated without drilling a tooth and instead you can use chemical remineralisation
once the enamel surface is fully cavitating to the dentin now the bacteria have a pathway to enter the dentin and
It might be necessary to remove the infected dentinal tissue and replace it with a dental filling which allows the tooth to chew
If the infection is so large the entire top of the tooth needs to be removed a dental crown can be used to replace it
Ultimately, these restorative treatments are useful
But they alone don't resolve the underlying cause of the caries lesion and can't prevent new caries lesions from forming
Alright as a quick recap
Dental caries lesions are the end result of the dental caries disease process
Dental caries lesions typically form in an environment where there are lots of sugars in the mouth and a pH below
5.54 enamel and below 6.2 to 6.8% amande dentin that environment favors bacteria like mutant
streptococcus e in lactobacillus which
Demineralized enamel and the dentin beneath it and if untreated it can eventually result in a cavity caries lesion
Diagnosis is done by visual inspection and radiographic imaging and treatment and prevention includes stopping D mineralization and promoting
Remineralization as well as reducing levels of harmful bacteria and restoring the surface of the tooth if needed
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