The Morning Drill: July 8, 2011

A collection of dentistry and health related links/comments to start your day.

Mom's Antidepressant Use Linked to Autism Risk in Children

Use of selective serotonin reuptake inhibitors (SSRIs) by pregnant women may increase the risk for autism spectrum disorder (ASD) in their offspring, new research suggests.

In a study of more than 1800 children, investigators found an adjusted 2-fold increased risk for ASD among mothers who used an SSRI during the year before delivery and a 3-fold increased risk when SSRIs were ingested during the first trimester.

"The potential association between use of antidepressants during pregnancy and risk of [ASDs] has never been investigated before," lead author Lisa A. Croen, PhD, senior research scientist and director of the Autism Research Program at Kaiser Permanente Northern California (KPNC) in Oakland, told Medscape Medical News.

However, she noted that the results "should be interpreted with extreme caution" and that further studies are needed to determine if this association represents a causal connection.

"At this point, we do not recommend that women make any changes to their treatment approach for depression and/or anxiety," said Dr. Croen.

Instead, she recommends that those prescribed SSRIs during pregnancy discuss the issue with their doctors.

"We know that there are real risks to the woman and their children if mental health disorders in mom go untreated, and there are real benefits to appropriate treatment.  So the potential risk of autism must be balanced with the real benefit of treatment," she said.

The study was published online July 4 in the Archives of General Psychiatry.

Dental implants seem safe for people taking low-dose oral bisphosphonates

Mainly, two groups of people take bisphosphonates to strengthen their bones: people who have osteoporosis and those who have bone cancer.  People with osteoporosis usually take a low dose of the medication by mouth (as a pill, for example).  By contrast, people who have cancer receive bisphosphonates in high doses intravenously (directly into the bloodstream).

We know that people who take bisphosphonates, either by mouth or intravenously, are at risk of developing a condition called osteonecrosis of the jaws, or ONJ.  People who develop ONJ suffer severe loss of the jawbone. The authors wondered whether people who took bisphosphonates were more likely to develop ONJ if they got dental implants than other people taking bisphosphonates.  They also wondered whether implants were more likely to come loose in patients who took bisphosphonates than in other patients.

They found three studies that involved 217 people who took bisposphonates by mouth for up to four years before they got dental implants.  Overall, the group had 840 implants.  All of the studies recorded how many implants stayed in place for up to four years after placement.  They found no studies that involved people taking high doses of bisphosphonates intravenously. Since the authors could not find any research articles about people taking bisphosphonates intravenously, they looked at six published expert opinions and treatment guidelines.

Authors' findings
None of the people who took bisphosphonates by mouth developed ONJ after implant placement, and for the first four years after placement, the implants remained functional. For people taking bisphosphonates intravenously, most of the guidelines said they should not have dental implants placed.

Conclusions
People who take low doses or bisphosphonates by mouth can consider having dental implants put in place without increased worry about developing ONJ or concern about the stability of the implant. Dental implants, however, are not recommended for people taking high doses of bisphosphonates intravenously. Talk to your dentist about your options and the best course of treatment for you.

Source: Madrid C, Sanz M. Clinical Oral Implants Research. 2009;20 Suppl 4():87-95

Why did my dentist ask me about my swimming pool?

It may seem odd that when a patient sits in my dental chair I might ask about their swimming habits.  This summer thousands of folks will be splashing away in their backyard pools.  Some of these people may be putting their dental health at risk.

Why?  Pool water can become very acidic if the chemistry is not monitored and adjusted regularly. Simply put, a poorly maintained swimming pool can erode away a lot of dental enamel. This loss of enamel can make teeth weak, discolored and prone to sensitivity and decay. The centers for disease control  (CDC) has reported numerous cases of individuals with compromised teeth related to extended exposure to acidic swimming pool water.  A recent report by the NY College of dentistry highlights the rapid erosion and dental problems associated with poorly maintained pools.

Mutations in One Gene Cause Craniosynostosis, Delayed Tooth Eruption and Supernumerary Teeth

Researchers have described a new, recessively inherited human syndrome featuring craniosynostosis, maxillary hyperplasia, delayed tooth eruption and extra teeth. They also identified causative mutations in a gene IL11RA.

In craniosynostosis, the sutures between skull bones become ossified prematurely, affecting skull shape and limiting space for the growth of the brain. It is observed in 1:2500 and often requires operative surgery. Supernumerary teeth are more common, and in most cases they also require dental surgery.

A combination of these anomalies was observed in four children of a Pakistani family living in Denmark. Extra teeth developed in positions suggesting that they may represent a third set of teeth, the formation of which is normally prevented in humans.

The parents of the family were first cousins, which made it possible to localize the gene in the genome (so called homozygosity mapping) and identify the mutation, causing a change of a single amino acid, in a gene for interleukin 11 receptor alpha (IL11RA). This is a protein on cell surface that binds the extracellular interleukin 11 and makes possible for the cells to sense the presence of this factor. When tested in cultured cell lines, the mutation inactivated the function of the receptor.

The researchers also found four other mutations in IL11RA in patients from Pakistan, England and The Netherlands.

"This is a quite novel discovery as IL11 -- or the signaling pathway it belongs to -- has not previously been associated with any inherited human disorders," says Dr. Pekka Nieminen, the leader of the study (University of Helsinki). "The results show that IL11 signaling is essential for the normal development of craniofacial bones and teeth, and that its function is to restrict suture fusion and tooth number."

Enjoy your morning!