Dental treatment for the pregnant patient: Part 2

What drugs that my dentist may use or prescribe are safe during pregnancy?

To answer this question I would like to reference a great presentation that is available for viewing online entitled:

Drug Therapy in the Pregnant Dental Patient By Doreen Matsui MD, Associate Professor, Department of Paediatrics
Children’s Hospital of Western Ontario

The presentation was posted online approximately 2011 but the material is still relevant today. And some of what she has to say may surprise you.

Here is a summary of some information Dr. Matsui presents:

• Less than 50% of women know they are pregnant by the 4th week\
• Approximately 20% of women still don’t know they’re pregnant by 8th week.
• One half of pregnancies are unplanned.

So there is a likelihood that a woman may have dental treatment while she is unaware she is pregnant and may also take medication while she is unknowingly pregnant.

Further points:

• Most drugs cross the placenta to some degree, so it is important to consult with your doctor or pharmacist before taking any medication during pregnancy, even over the counter medication.
• Only a small percentage of drugs on the market have been known to cause birth defects in fetuses.
• Many drugs are approved for over the counter or prescription use before the long term safety of the drug has been clearly established.

 

• When drug companies do testing on medications that they want to bring to market, they generally do not use pregnant women as test subjects; so if a drug company claims a medication is safe and effective, that opinion could be based on testing  & research conducted on young healthy males, while those claims of safety may not hold true for a pregnant woman or her fetus.
• Risk to fetuses or pregnant women have been found for drugs that have already been on the market for between 2 years to 10 years.

Ed. Note: There are many physicians who will not prescribe a new drug until it has been on the market for at least 5 years if there is already another drug that has a long term safety data and is effective. This is a rule to consider if you are pregnant: stick with a tried and true medication.

Can Nitrous Oxide (Laughing Gas) be used During Pregnancy?

Nitrous oxide or laughing gas is a drug commonly used in dentistry to relax or sedate nervous patients. Is it safe to use for the pregnant dental patient? To get an opinion on this matter I consulted the following article. 

The paper is titled: “Nitrous Oxide and the Inhalation Anesthetics” and was written by Dr. Daniel E Becker, DDS and Morton Rosenberg, DMD. Anesth Prog. 2008 Winter; 55(4): 124–131. (Copyright 2008 by the American Dental Society of Anesthesiology)

Here is a brief summary of key points they make regarding the use of nitrous oxide sedation during pregnancy:

• “Clearly, all elective dental treatment should be avoided during pregnancy, especially during the first trimester.”
• However, urgent dental care frequently is required for patients who are pregnant.
• Under these circumstances, it is not unusual for the patient to be anxious and fearful, often extremely so.

• For these patients, apprehension should be allayed by using the safest agents available, and nitrous oxide fulfills this requirement.
• For ethical reasons, prospective studies cannot address this issue, but retrospective studies of nearly 6000 general anesthetics in pregnant patients failed to reveal any adverse outcomes for patient or fetus. (Virtually all these anesthetics included nitrous oxide.) 
• For the pregnant patient who is apprehensive and requires urgent dental care, nitrous oxide should be regarded as the sedation agent of choice.\
• Any evidence of complication during pregnancy certainly warrants consultation with the patient’s obstetrician.”

Can silver fillings be placed during pregnancy?

Dental materials have improved over recent years and in most situations tooth coloured fillings can be placed in situations where silver fillings once were the ideal material.  

However an occasion arises where a silver filling might be considered, is a silver filling okay to be placed in the pregnant dental patient?   Let’s look at what experts at the Hospital for Sick Children (in Toronto, Canada) have to say. 

The hospital has a service called Motherisk, that provides advice to pregnant women and health care professionals regarding risks to the fetus from exposure to drugs, chemicals, diseases, radiation and environmental agents. Motherisk is an excellent resource for pregnant and breast feeding women and their website is www.motherisk.org


I will summarize Motherisk’s opinion on whether silver fillings are safe to place in pregnant women:

​Silver filling contains 50%metallic mercury mixed with other metal

​Silver filling material has advantages over other filling materials; however, there is a concern: when you chew on a silver filling, mercury can be released as vapour or fine particles, which can be inhaled or ingested by the patient. 

Although mercury is a toxin, its release from silver filling (also known as dental amalgam) is minimal—estimated to be 10 micrograms per day in the average patient, whereas the World Health Organization’s maximum recommended intake of mercury for a 100 pound female is 90 micrograms per day. So the amount of mercury released from silver fillings is well below the allowable daily limit for safe mercury exposure and Motherisk therefore considers it a safe filling material for pregnant women.

I would add that there are other sources of mercury that we are exposed to including fish and shellfish and other environmental sources. Studies have shown that whether you have silver fillings in your teeth or not, you are essentially going to have a similar amount of daily mercury exposure than someone who does not have any silver fillings.

Motherisk advises that hydrogen peroxide, a common bleaching agent that dentists use to whiten your teeth, can increase mercury release from filling, so you should avoid bleaching your teeth while you are pregnant.

Health Canada states that amalgams should not, if possible, be placed or removed during pregnancy, which, according to Motherisk “might be a rather conservative approach, as studies and case reports of amalgam exposure during pregnancy have not documented any toxicity, including birth defects, neurologic issues in the newborn, spontaneous abortions, or reduction in fertility.”
​
Another source of information regarding the placement of silver fillings during pregnancy is an article I quoted in the part one of Dentistry for the Pregnant Patient:

Health during Pregnancy and Early Childhood: Evidence –Based Guidelines for Health Professionals. 

This article is available for free at :  http://www.cdafoundation.org/portals/0/pdfs/poh_guidelines.pdf

These guidelines were written by a group of U.S. State and national medical, dental, and public health experts, in 2010… they reviewed all of the current research in the area of dental care and dental health for the pregnant patient and developed a set of guidelines for dentists to follow. Most importantly, the findings and recommendations in their report are fully endorsed by the American College of Obstetricians and Gynecologists who oversaw the entire project, in collaboration with the California Dental Association. 

Here are key points from the guidelines regarding silver fillings and pregnancy:

• After review of about 200 scientific studies, the U.S. Food and Drug Administration (FDA) on July 27, 2009, reaffirmed its view that dental amalgam is a safe, effective material for use in dental restorations.
• According to the FDA, the levels released by dental amalgam fillings “are not high enough to cause harm in patients,” and “the best available scientific evidence supports the conclusion that patients with dental amalgam fillings are not at risk.”
• It further determined that “long-term clinical studies in adults and children aged 6 and older with dental amalgam fillings have not established a causal link between dental amalgam and adverse health effects."
• The FDA recommends delaying removal of silver fillings until after pregnancy or weaning if a rubber dam and high-speed suction cannot be used. However, even during placement and removal, studies do not show any adverse reproductive effects if safe amalgam practices are used.

My conclusion: Silver fillings are safe material. If a patient requires a filling while they are pregnant I certainly discuss alternatives such as tooth coloured fillings (also known as resin)that do not contain mercury. There are circumstances
where putting in a tooth coloured filling would not be wise, for example if the cavity is deep under the gums and the area cannot be kept dry during the placement of the filling, a resin filling, if placed, will fail , leading to more decay in the tooth and possible tooth loss. A silver filling, on the other hand, can be placed in wet environments and still be successful. So, while many patients want white or tooth coloured fillings, silver fillings still can serve as a valuable material to offer patients when the need arises.

Other Treatment Recommendations for the Pregnant Dental Patient

Elective (non-urgent) care is best left for the second trimester, however urgent treatment can be done any time during pregnancy. The goal of dental treatment in the first trimester is to eliminate source of dental infection or pain

How to promote the dental health of the developing baby while it is still in the womb.

During pregnancy, the baby’s teeth are already developing.

• The enamel of the first set of teeth (baby teeth) is already beginning to harden at the 14th week in the womb.
• The enamel of the child’s permanent teeth front teeth is already starting to harden 3 months after the child is born
• The baby’s permanent molar enamel is starting to harden at birth.
• The period of enamel formation is very important for good dental health. Teeth with good quality enamel will look better and can be more resistant to decay.

So, a mother’s health and nutrition during pregnancy can have a profound effect on the health of the baby’s teeth, as does the health and diet of the child during its first 8 years of life, when the bulk of tooth formation occurs. 

Pregnant women should consult with their doctor for nutritional advice during pregnancy.

• Getting the proper amount of calcium and Vitamin D is important for normal tooth (and bone) development
• The Mayo clinic does recommend pregnant women take vitamin supplements
• An example of a pregnancy vitamin supplement is Materna.

The use of fluoride supplements during pregnancy.

I came across at least one website offering prenatal advice regarding the use of fluoride supplements during pregnancy. They suggested asking your dentist if they are necessary. The short answer is no.

For a detailed answer you can refer to a thorough article written by a group of health experts commissioned by the US Centre for Disease control. The report was titled “Recommendations for using fluoride to prevent and control dental caries in the United States” (published June 2013), and is available at: 

http://www.cdc.gov/fluoridation/factsheets/fl_caries.htm

The article states: “Use of fluoride supplements by pregnant women does not benefit their offspring.” However the report does recommend pregnant women drink water fluoridated water (ideally at 1ppm fluoride like we have in Toronto
Canada, and use a fluoridated tooth paste.

If fluoride is consumed in ideal amounts it can strengthen the enamel of teeth. However if it is taken in excess amounts it can disrupt the enamel formation process while the tooth is developing, resulting in softer enamel; the enamel will contain more protein but less hard mineral. This condition is called fluorosis. 

• In a very mild case of fluorosis, about one quarter of the tooth surface will have white spots.
• In a mild case, less than half of the tooth surface can be covered in a paper white coating.
• In a severe case, the tooth will have a pitted surface and brown staining due to poor quality enamel.
• In pregnancy, the placenta does limit the amount of fluoride that can reach the developing baby teeth, somewhat limiting the risk or severity of dental fluorosis.

However once the baby is born and during the first 8 years of life, you want to ensure your child is getting optimal levels of fluoride in their diet.

How to provide optimal levels of fluoride in the diet:

If the mother is drinking fluoridated water, the breast milk will have adequate fluoride levels.

If the infant is bottle fed, the formula should be made with optimally fluoridated water (1 ppm fluoride, i.e. Toronto tap water.)

Use a pea sized amount of fluoridated toothpaste on your child’s tooth brush once a child is old enough to spit the toothpaste out. Brush twice a day.
Supervise your child when they brush. You should brush for your child until approximately 6 years of age to ensure the teeth are getting brushed well.

If the child is too young to spit out the toothpaste they should use plain water or a non-fluoridated toothpaste. But once they can spit, they should brush while supervised with fluoridated toothpaste.

 Folic Acid, Pregnancy and Dental Health 

It has been proven that a diet containing folic acid before and during pregnancy reduces the risk of neural tube defects. It may also reduce the risk of oral congenital defects such as cleft lip and palate. 

Oral clefts are among the most common congenital malformations, with an estimated prevalence of 1.5 per 1,000 births.

As part of routine care for pregnant patients and all women of childbearing age, dental professionals should remember to ask women if they take folic acid found in a multivitamin supplement such as Materna and to stress its importance.

One more tip for pregnant patients when at the dentist:

After your 20th week of pregnancy you should stay semi-reclined in the dental chair or a pillow should be kept under your right hip keep the weight of your developing baby from interfering with your blood circulation. This will help prevent low blood pressure and nausea during your dental appointment. 

If you should have any questions regarding your dental care please feel free to call our office or email us. We would be happy to hear from you!

Dr. Jeff Shnall