As the smallest member of the clan grows older, it’s time for my reality-based revision to move on from normal neonates to something else. We’ve made it through neonatal nasties and tourniquets on toes. It’s something more commonplace that keeps us up at night – something we’ve all been through – teething.
Only about 1 in 2000 babies are born with teeth; most of us had to wait a while before they came through. Cutting through the gingiva from their origin in the mandible/maxilla causes localised trauma, inflammation, and several systemic effects, such as low-grade fever and loose stools. Local effects and systemic effects are mediated by cytokine and prostaglandin release, as well as by the possible translocation of oral bacteria through the gingival breach.
The embryology of teeth
Teeth develop from the ectoderm of the first pharyngeal arch and neural crest elements at around six weeks of embryonic development. Layers of cells form as epithelial thickenings before moving through the stages of bud, cap, bell and then terminal differentiation into individual teeth. The odontoblasts (derived from the neural crest) form the predentin before calcifying to dentin. It’s the ameloblasts that produce the tooth enamel.
Natal teeth (those present at birth) have a genetic predisposition, with up to 60% of cases reporting a family history. They are also associated with an increased incidence of cleft lip/palate. Natal teeth are a known feature of:-
- Ellis-van Creveld syndrome (chondroectodermal dysplasia)
- Jackson-Lawler syndrome (pachyonychia congenital 2)
- Steatocystoma multiplex with natal teeth
- Hallerman-Streiff syndrome (oculomandibulofacial syndrome with hypotrichosis)
How do you number the primary teeth?
There are almost as many numbering schemes as there are teeth. In Australia, we use the Fédération Dentaire Internationale – look at the graphic below to refresh your memory.
If you work in the US, you might choose the universal numbering system, which is not, as you might think, used universally.
Common symptoms of teething
Macknin et al. convinced some of their co-workers at the Cleveland Clinic to keep an 8 month log of 125 of their children. They recorded twice daily temperature measurements as well as filling in a daily symptom report and a record of their dental eruptions. Despite the fact that it seems that my children were teething all of the time they found that symptoms increased 4 days before an eruption, the day of and 3 days after – just an 8 day window. The parents reported drooling, sucking and general grumpiness coupled with the presence of a facial rash and ear or gum rubbing.
Though teething has been shown to raise one’s temperature, it is only by a minuscule amount, around 0.6°C, and that will depend on how accurately it is measured. The parents in the Macknin cohort all used tympanic thermometers, and whilst they are not overly accurate for individual measurements, there were used to compare like with like.
Myths surrounding teething
The Macknin et al survey also refuted some common misconceptions. Teething was NOT associated with looser stools, vomiting or high temperatures. The problem is that these myths persist, not only in the general population but also amongst healthcare professionals. Admittedly, I was taught nothing about teething in medical school (or since, hence this post). A survey carried out in New Zealand found that 31% of health care professionals though that teething could cause nappy rash, 27% thought it could cause diarrhoea, 19% a runny nose and though that teething could cause mouth ulcers.
So how should we treat the pain of erupting teeth?
Teething isn’t the life-threatening illness we once thought it was, but it certainly is sanity-threatening for a parent.
Some infants achieve some degree of pain relief by chewing on anything they can. Solid, silicone-based teething rings are probably safer than water-filled ones as they cannot leak. Other parents swear by frozen veggies.
Most of the over-the-counter teething gels contain lignocaine hydrochloride.
Other teething gels, such as Bonjela®, contain choline salicylate. These have a local anti-inflammatory as well as local anaesthetic effect. The salicylate component was removed from the UK formulation in 2002 though there have been case reports of chronic salicylate toxicity in Australia.
There is also the option of using systemic analgesia in the form of appropriate weight-based doses of paracetamol.
And, more importantly, how should we NOT treat teething pain?
Whilst it was not until the mid-19th century that teething stopped being listed as a cause of death in young infants, it is now more likely that some treatments are more deadly.
Lancing (forming a cross-shaped incision over the troubling tooth) was a popular form of treatment in 16th century Europe and persisted until the late 19th century where it fell out of favour. Despite this a similar practice takes place in sub-Saharan Africa today. Removing the budding ‘tooth worms’ with non-sterile implements like knitting needles and bicycle spokes is a form of infant oral mutilation. Healers think the ‘tooth worms’ cause some of the common diarrhoeal illnesses – the erupting tooth bud looks similar to parasitic worms found in stools. If the child does not suffer from serious infection then they may still go on to develop permanent facial disfigurement.
Whilst we know that homoeopathy is of no benefit, Hyland’s baby teething tablets were withdrawn in the US after concerns that non-homoeopathic doses of belladonna extract may have led to around 400 adverse events and ten deaths. Whilst the alkaloid has not been found in the Australian product, the supplier, in conjunction with the TGA, initiated a recall.
Amber necklaces, all the rage with a certain sector of the populace, have a number of health benefits (allegedly) – including reducing inflammation and the pain of teething. I’ve not found any high, medium, or low level evidence to confirm these claims but I have found a number of case reports detailing near strangulation events. Teething toddlers are inquisitive creatures. As they clamber over the furniture in their quest for something else valuable to break the necklace may get caught, leading to near-fatal consequences. One of our roles in emergency medicine is to advocate for those patients that cannot speak for themselves. As Tim Horeczko would say “You are the champion of the child in front of you.”
Next time I’ll look at some basic dental anatomy, dealing with dental damage and how much you should leave for the Tooth Fairy.
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Ispas RS, Mahoney EK, Whyman RA. Teething signs and symptoms: persisting misconceptions among health professionals in New Zealand. New Zealand Dental Journal. 2013 Mar 1;109
McIntyre GT, McIntyre GM. Teething troubles?. British Dental Journal. 2002 Mar 9;192(5):251-5.
Voelker R. Safe Relief for Teething Symptoms. JAMA. 2016 Nov 15;316(19):1957-.
Williams GD, Kirk EP, Wilson CJ, Meadows CA, Chan BS. Salicylate intoxication from teething gel in infancy. Med J Aust. 2011 Feb 7;194(3):146-8.
Zone CP, Guide S. Teething pain in babies. Sign. 2017 Jan 13;3531(937).