It’s that time of year… no, not Christmas! In our house it’s Dentist time! While training I was told by a wise veterinary friend that “Doctors shouldn’t treat pets or teeth; they’re not vets or dentists…” and after a course of “stored-up” Metronidazole hadn’t helped my “sensitive tooth” my routine check-up visit has turned into “a repair appointment”. I should have taken my friend’s excellent advice…my issue was not an infection and my abilities in dental diagnosis are clearly lacking! However as Microbiologists we are allowed to consider the causes of dental infections and how they might lead to patients needing antibiotic treatment or even being admitted to hospital.
“What time did you go to the Dentist?”
“Two thirty” (Ha ha Tooth hurty, tee hee!)
“What time did you go to the Dentist?”
“Two thirty” (Ha ha Tooth hurty, tee hee!)
What types of dental infections are there?
There are two main types of dental infections; local (dental caries and gingivitis) and systemic.
Dental disease is very common Worldwide. In the developed World it is estimated that 25% of adults aged 20-64 years have untreated tooth decay and 17% of those 65 years and over have no natural teeth!
It’ll come as no surprise that we humans have two sets of teeth during our lifetimes. The first set is known as deciduous teeth because we lose them in childhood (they fall like deciduous leaves from trees); they are also known as baby or milk teeth. Teething is the term often used to describe the time when deciduous teeth are appearing. During my time in paediatrics I remember reading a fantastic study (reference below), of hundreds of children, looking at the symptoms of teething to see if there were any patterns and the conclusion was that the only consistent thing that teething causes is the presence of teeth! Our 20 deciduous teeth start to appear from about 6 months old until we are about 2 years old, and we them lose them between 6 and 12 years of age. Our 32 permanent adult teeth appear as we lose our deciduous teeth.
Structure of a tooth
There are two main types of dental infections; local (dental caries and gingivitis) and systemic.
Dental disease is very common Worldwide. In the developed World it is estimated that 25% of adults aged 20-64 years have untreated tooth decay and 17% of those 65 years and over have no natural teeth!
It’ll come as no surprise that we humans have two sets of teeth during our lifetimes. The first set is known as deciduous teeth because we lose them in childhood (they fall like deciduous leaves from trees); they are also known as baby or milk teeth. Teething is the term often used to describe the time when deciduous teeth are appearing. During my time in paediatrics I remember reading a fantastic study (reference below), of hundreds of children, looking at the symptoms of teething to see if there were any patterns and the conclusion was that the only consistent thing that teething causes is the presence of teeth! Our 20 deciduous teeth start to appear from about 6 months old until we are about 2 years old, and we them lose them between 6 and 12 years of age. Our 32 permanent adult teeth appear as we lose our deciduous teeth.
Structure of a tooth
Okay basic tooth anatomy time (and it has to be basic, to keep in line with the rest of his anatomy knowledge – Editor Chief-in-Charge). The bit of the tooth that sticks up from the gum is called the crown and is covered in enamel, the hardest structure in the human body, under which is the dentin layer. The roots of the tooth anchor the tooth and extend into the bone of the mandible for the bottom teeth and the maxilla for the upper teeth. Within the space between the root and the bone is the periodontal membrane and cementum (tooth cement) which joins the tooth together and allows a bit of movement in the tooth’s socket to help to protect it from being bashed about whilst biting and chewing.
The inside of the tooth is called the pulp and this contains the blood vessels and nerves supplying the tooth. The soft tissue surrounding the tooth at the level of the gum is known as the gingiva.
How do dental infections start?
Dental infections start as a result of plaques of bacteria on the surface of the tooth. If the plaque is on the surface of the tooth above the gingiva it leads to dental caries, if it is beneath the gingiva it causes gingivitis and periodontal inflammation.
Untreated infections can extend along the areas of least resistance to cause deep infections in the bones of the maxilla or mandible or in the soft tissues of the mouth, face and neck.
What bacteria cause dental infections?
The bacteria that cause dental infections are usually part of our normal mouth flora. Yep, these are what are known as endogenous infections; our own flora is attacking us!
Within the mouth, different bacteria prefer different locations:
Dental infections are usually polymicrobial; multiple bacteria are acting together to cause the infection. Dental plaque has been studied for hundreds of years, ever since Antonie van Leeuwenhoek (the inventor of the microscope in the 1670s) first started to examine his own dental plaque. So far over a 1000 species have been identified in dental plaque, although some are more pathogenic than others, and some may even be innocent bystanders.
The most pathogenic bacteria in the mouth in terms of dental infections are:
The inside of the tooth is called the pulp and this contains the blood vessels and nerves supplying the tooth. The soft tissue surrounding the tooth at the level of the gum is known as the gingiva.
How do dental infections start?
Dental infections start as a result of plaques of bacteria on the surface of the tooth. If the plaque is on the surface of the tooth above the gingiva it leads to dental caries, if it is beneath the gingiva it causes gingivitis and periodontal inflammation.
Untreated infections can extend along the areas of least resistance to cause deep infections in the bones of the maxilla or mandible or in the soft tissues of the mouth, face and neck.
What bacteria cause dental infections?
The bacteria that cause dental infections are usually part of our normal mouth flora. Yep, these are what are known as endogenous infections; our own flora is attacking us!
Within the mouth, different bacteria prefer different locations:
- Tongue and inside the cheek – Streptococcus salivarius and Veilonella spp.
- Tooth surface – Streptococcus sanguinis, Streptococcus mutans and Actinomyces viscosus
- Gingiva – Fusobacterium spp., Prevotella spp. and anaerobic spirochaetes
Dental infections are usually polymicrobial; multiple bacteria are acting together to cause the infection. Dental plaque has been studied for hundreds of years, ever since Antonie van Leeuwenhoek (the inventor of the microscope in the 1670s) first started to examine his own dental plaque. So far over a 1000 species have been identified in dental plaque, although some are more pathogenic than others, and some may even be innocent bystanders.
The most pathogenic bacteria in the mouth in terms of dental infections are:
- Dental caries - Streptococcus mutans is the only bacterium consistently found in dental caries
- Gingivitis – predominantly associated with anaerobic Gram-negative bacilli (Prevotella intermedia, Capnocytophaga spp, Finegoldia magna and Peptostreptococcus spp.)
- Periodontal inflammation – mixed anaerobic Gram-negative and spirochaete bacteria (Porphyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans, Tannerella forsythensis and Treponema denticola)
Dental caries
Gingivitis
Don’t you just love bacterial names?! I particularly like Treponema denti ”cola”… especially as I was always told Coca Cola would rot my teeth… (and probably did!)
What factors allow normal flora to attack teeth?
So there must be more to dental infections than just the bacteria because if it was just down to the bacteria they would attack our teeth all the time.
Diet plays a major role in dental infections. The bacteria causing these infections produce acid from dietary sugars (especially sucrose) and are perfectly happy living at the lower pH that is caused, so they can continue producing more acid. The acid produced demineralises enamel which in turn allows bacteria to penetrate the tooth causing further demineralisation and so on. Eventually bacteria get inside and the tooth becomes inflamed and starts to be destroyed! Smoking also predisposes to gingival infections by damaging the soft tissue of the mouth.
The mouth tries to fight back by:
However, a diet high in sugar and acid (like our modern diet of fizzy drinks and chocolate) will overwhelm these defences and dental infections will occur.
How are dental infections treated?
Most times you visit the dentist you are not prescribed antibiotics. Common dental procedures include:
Fortunately it isn’t necessary to kill every bacterial species involved in a dental infection, the mouth’s own defences are good enough once the underlying issue is resolved, which is good as we have already discussed that there are possibly over 1000 species involved!
So only the most problematic or pathogenic need to be taken care of, if an abscess has formed, often as a result of ignoring a simpler problem, then a 7 days course of oral antibiotics is usually required. Typical antibiotics include Amoxicillin, Metronidazole and occasionally Co-amoxiclav. These all target the normal anaerobes that cause dental abscesses. An alternative for penicillin allergic patients would be Clindamycin. Once the abscess has settled down “surgical” correction of the underlying problem with a filling or root canal work is necessary to prevent it reoccurring.
How to prevent dental infections
There are a number of things we can do to reduce our risk of developing dental infections:
However, this is easier said than done for some of us and most of us have at least one weakness that predisposes us to dental infections. For me it’s the sugary food… I love chocolate! For the Editor Chief-in-Charge that means getting out of bed and brushing her teeth before she is served her breakfast!
But hold on! It’s nearly Christmas and that means sweets, chocolates and fizzy pop!!! Oh no… what am I going to do?! I know… brush more carefully, floss diligently and don’t tell my Dentist :-)
What factors allow normal flora to attack teeth?
So there must be more to dental infections than just the bacteria because if it was just down to the bacteria they would attack our teeth all the time.
Diet plays a major role in dental infections. The bacteria causing these infections produce acid from dietary sugars (especially sucrose) and are perfectly happy living at the lower pH that is caused, so they can continue producing more acid. The acid produced demineralises enamel which in turn allows bacteria to penetrate the tooth causing further demineralisation and so on. Eventually bacteria get inside and the tooth becomes inflamed and starts to be destroyed! Smoking also predisposes to gingival infections by damaging the soft tissue of the mouth.
The mouth tries to fight back by:
- Being bathed in saliva (which is pH neutral, supplies calcium to help re-mineralise the tooth and contains antibacterial compounds such as lysozyme)
- The tongue “brushes” the teeth removing food
- By producing a protein film on the tooth’s enamel, this sterile coating called the “acquired pellicle” creates a barrier to acid.
However, a diet high in sugar and acid (like our modern diet of fizzy drinks and chocolate) will overwhelm these defences and dental infections will occur.
How are dental infections treated?
Most times you visit the dentist you are not prescribed antibiotics. Common dental procedures include:
- Closer attention to tooth cleaning, and occasionally specialist toothpaste products and antiseptic mouth washes are used in the treatment of plaque formation and gingivitis.
- Fillings (technically called restorative therapy) to treat dental caries, where the infected material is removed and replaced with a tooth-like compound.
- Root canal filling is when infected pulp material is removed and cleaning out the root before repairing the tooth with a tooth-like compound.
Fortunately it isn’t necessary to kill every bacterial species involved in a dental infection, the mouth’s own defences are good enough once the underlying issue is resolved, which is good as we have already discussed that there are possibly over 1000 species involved!
So only the most problematic or pathogenic need to be taken care of, if an abscess has formed, often as a result of ignoring a simpler problem, then a 7 days course of oral antibiotics is usually required. Typical antibiotics include Amoxicillin, Metronidazole and occasionally Co-amoxiclav. These all target the normal anaerobes that cause dental abscesses. An alternative for penicillin allergic patients would be Clindamycin. Once the abscess has settled down “surgical” correction of the underlying problem with a filling or root canal work is necessary to prevent it reoccurring.
How to prevent dental infections
There are a number of things we can do to reduce our risk of developing dental infections:
- Regular dental check-ups (at least yearly) and twice yearly visits to the hygienist to spot problems before they become too bad
- Brush our teeth twice a day – but not within 30 minutes of eating or drinking acidic food or drink!
- Floss between our teeth at least once a day
- Reduce the amount of sugary foods and fizzy drinks we consume
- Stop smoking
However, this is easier said than done for some of us and most of us have at least one weakness that predisposes us to dental infections. For me it’s the sugary food… I love chocolate! For the Editor Chief-in-Charge that means getting out of bed and brushing her teeth before she is served her breakfast!
But hold on! It’s nearly Christmas and that means sweets, chocolates and fizzy pop!!! Oh no… what am I going to do?! I know… brush more carefully, floss diligently and don’t tell my Dentist :-)
Reference:
Symptoms associated with infant teething: a prospective study, Macknin ML1, Piedmonte M, Jacobs J, Skibinski C. Pediatrics. 2000 Apr;105 (4 Pt 1):747-52.
Symptoms associated with infant teething: a prospective study, Macknin ML1, Piedmonte M, Jacobs J, Skibinski C. Pediatrics. 2000 Apr;105 (4 Pt 1):747-52.
RSS Feed
