Our baby is currently erupting his first tooth. And Im relieved. It’s finally here. After 5 months of biting and drooling we’ve finally made some progress. Being a very goal-oriented individual, I find that I am sometimes measuring my babe’s progress from milestone to milestone and I get somewhat anxious when a few weeks go by and nothing happens. Since nothing dramatic has happened for the last two months (ever since we achieved independent sitting), I`ve gone a bit crazy. I know lots of stuff is happening. He’s getting stronger and his coordination is getting better and he’s making movements towards independently moving but its nothing I can call his grandparents about.
But I can call them and tell them about this tooth.
One of the things that The Adequate Father believes is that baby or primary or deciduous teeth are harder the later they erupt. At least, I remember him telling me that. And he remembers me telling him that. It’s a good thing neither of us has been subpoenaed as a witness. We are obviously unreliable. But, regardless of who told whom what, is that true? Are baby teeth like clay objects in a kiln? Do they harden or develop stronger or thicker or sparklier enamel the longer they are under the gums? I set off to find out.
A search of Pubmed using “Dentition, Primary” and “enamel,” limited to humans and english (hey, I am unilingual and ashamed of it) yielded only 12 citations and most of those were about the corrosive properties of acidic beverages. I took out “enamel” and got 88 citations.
I was unable to answer the question.
I found out that the timing of tooth eruption is genetic and that researchers have found 5 single-nucleotide polymorphisms (SNPs) that are associated with delayed tooth eruption and which are also close to loci associated with other organ development suggesting teething is related to other developmental processes. One of these loci also correlated with a need for orthodontic treatment later. (D Pillas et. al. PLoS Genet 6, e1000856; 2010). Hmm…better start saving.
I found out that enamel formation is slowed during periods of stress (Front Oral Biol. 2009;13:116-20 – don’t you lovethe name of this journal. Frontiers of Oral Biology…how exciting!). There is a “neonatal” line on primary teeth that corresponds to a period of slow or stalled enamel formation that occurs during the perinatal period. That’s right. Being born might be “natural” but it is stressful enough that there isn’t any energy left over for mundane tasks like laying down enamel. Incidentally, I had severe lines/ dents appear on both my thumb nails around the time of birth. These lines grew out from the nail matrix and only disappeared when nail growth carried them towards my finger clippers. apparently, parturition was stressful for me too.
I found out that there is a correlation between the number of erupted teeth and the height and weight of a child, at least, a Polish child (Anthropol Anz. 2002 Jun;60(2):199-207.)
I also found out that academic anthropologic dentists really like to publish their investigations of caveman teeth.
At any rate, unable to find a real study, I turned to the poor substitute of biologic plausibility and did some reading about how teeth form.
Enamel formation in baby teeth begins somewhere around the junction of the first and second trimesters of pregnancy. First, a “scaffolding” of sorts made from proteins and connective tissue which is partially mineralized is created. This is then fully mineralized. By the time the tooth erupts, mineralization is complete and the cells responsible have broken down. Enamel cannot regenerate or repair itself. So, while it makes sense to think that a longer time span between the third or fourth month of pregnancy and tooth eruption will result in “more” or “denser” or “harder” mineralization, I was unable to find any evidence to support this idea.
Regardless, this first tooth is super exciting. I can’t wait for all of the red-faced howling that is about to ensue when I try to brush it.