Leukemia (Blood Cancer)

Tooth Decay and Cavities 

Dental caries disease also called tooth decay refers to demineralization or weakening of the teeth and the end result of caries disease. It carries the lesion. An advanced caries lesion can progress to the point where the tooth surface forms cavitations 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 cement enamel 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 the 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 Edano 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 help to neutralize the acid in the mouth as those glycoproteins like mucin thicken the saliva. Saliva also has calcium and phosphate which serve as 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 can 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 microcolonies that coalesce which creates a layer of dental plaque.

     What is the type of biofilm? Compared to a microcolony 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 microcolonies and to the surface in order to bring in a steady supply of food as an analogy if bacteria were ants than a microcolony 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 5.5enamel 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 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 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 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 are 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 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 re-mineralization products that have fluoride can help rematerialize spots where the 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  re-mineralization, 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 re-mineralization as well as reducing levels of harmful bacteria and restoring the surface of the tooth if needed.  

 

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