You "Wnt" To Limit Teeth

Wnt signaling limits tooth number; abstract:

Tooth agenesis is one of predominant developmental anomalies in humans, usually affecting the permanent dentition generated by sequential tooth formation, and in most cases caused by mutations perturbing epithelial Wnt/β-catenin signaling. Also loss-of-function mutations in the Wnt feedback inhibitor AXIN2 lead to human tooth agenesis. We investigated the functions of Wnt/β-catenin signaling during sequential formation of molar teeth using mouse models. Continuous initiation of new teeth, observed after genetic activation of Wnt/β-catenin signaling in the oral epithelium, was accompanied by enhanced expression of Wnt antagonists and a downregulation of Wnt/β-catenin signaling in the dental mesenchyme. Genetic and pharmacological activation of mesenchymal Wnt/β-catenin signaling negatively regulated sequential tooth formation, an effect partly mediated by Bmp4. Runx2, a gene whose loss-of-function mutations result in sequential formation of supernumerary teeth in the human cleidocranial dysplasia syndrome, suppressed the expression of Wnt inhibitors Axin2 and Drapc1 in dental mesenchyme. Our data indicate that increased mesenchymal Wnt signaling inhibits the sequential formation of teeth, and suggest that Axin2/Runx2 antagonistic interactions modulate the level of mesenchymal Wnt/β-catenin signaling, underlying the contrasting dental phenotypes caused by human AXIN2 and RUNX2 mutations.

Zero Alcohol Listerine

I’ve switched from using regular Listerine to the Zero Alcohol version.  Given the possible links between alcohol and oral cancer, I thought it prudent.  However, note that there is no evidence linking alcohol-containing mouthwash and oral cancer, at least according to this study, abstract:

BACKGROUND:

Use of mouthwash and an increased risk of oral cancer has been a source of controversy for decades. A meta-analysis of epidemiological studies of mouthwash and oral cancer and, specifically, mouthwash containing >25% alcohol, was undertaken.

METHODS:

Summary estimates were obtained with maximum likelihood estimates from random effects models. Sensitivity analyses were conducted to evaluate the influence of various inclusion.

RESULTS:

Eighteen studies were included in the meta-analysis. There was no statistically significant associations found between regular use of mouthwash and risk of oral cancer (RR=1.13; 95% CI (0.95-1.35)). There was no significant trend in risk of oral cancer associated with increased daily usage of mouthwash (p=0.11). There was no association between reported use of mouthwash specifically containing alcohol and risk of oral cancer (RR=1.16; 95% CI (0.44, 3.08)).

CONCLUSIONS:

This quantitative analysis of mouthwash use and oral malignancy revealed no statistically significant associations between mouthwash use and risk of oral cancer, nor any significant trend in risk with increasing daily use; and no association between use of mouthwash containing alcohol and oral cancer risk.

But, still, why take the chance?  Studies are often refuted and overturned.  It happens all the time.  My view is, if an alcohol-free version exists, why not use it?  Just playing the percentages, so to speak.  My understanding is that the alcohol-free version is just as effective as regular, so there’s no loss while you can play it safe – just in case a future study reverses the conclusion cited above. What have you got to use?  As to why use Listerine at all – I find it reduces the accumulation of tooth plaque, likely by controlling the numbers of mouth bacteria.