The answer about whether dentures can cause a false positive result on a breath alcohol test depends on whether you ask criminal defense attorneys, law enforcement personnel or scientists. All agree that false teeth can affect the test, but some maintain that certain provisions can prevent it.
Factors
If you have had an alcoholic beverage, residue can collect in your false teeth, according to the National Association of Criminal Defense Lawyers. This is called mouth alcohol and it can happen even if you never ingested the drink. The website DUIAttorney suggests that food particles also trapped there can absorb even more residual alcohol.
Research
The NACDL cites a study by Richard Harding with the Wisconsin State Laboratory of Hygiene and published in the Journal of Forensic Science in July 1992. Twenty-four people wearing dentures were given 80-proof brandy. They swished it around in their mouths for two minutes then spit it out. Scientists administered breath alcohol tests 20 minutes later. Two of the 24 subjects showed traces of alcohol on the Breathalyzers, although in both cases the readings were less than or equal to 0.01. Harding maintains that dentures cannot affect BrAC readings after 20 minutes have passed since drinking.
Law Enforcement Safeguards
The Virginia Department of Forensic Science indicates that this 20-minute observation period provides a safeguard against false positive BrAC readings in denture-wearers. According to DUIAttorney.com, a 20-minute observation period allows a suspect a period of time during which alcohol can leave his breath if he recently had a single drink. Law enforcement officials maintain that it prevents inaccurate readings in denture-wearers, as well. Some police departments use a breath alcohol tester called the Intoxilyzer 5000, which has a built-in "slope detector" designed to weed out the effect of mouth alcohol trapped in dentures or dental work. A slope detector works by identifying alcoholic content from deep or aveolar breath where true results are ostensibly obtained by measuring alcohol content along the entire length of an exhalation, according to Michael P. Hlastala,
professor of physiology and biophysics and of medicine at the University of Washington in Seattle.
Opposing Opinions
Hlastala indicates that slope detectors are not foolproof in weeding out false positive BrAC results in denture-wearers because the devices can only suggest when air should be coming from the alvaolar area and not the mouth. They cannot prove that it actually is. If a suspect is nervous or upset and is breathing irregularly, an erroneous slope detector reading can result. Hlastala believes that the presence of mouth alcohol can raise BrAC readings up to 0.03 to 0.04. This can be the difference between a reading that is just under the limit or just over.
Recommendations
The NACDL suggests that if your state offers blood or urine tests for alcohol and you feel that you run the risk of a false positive on a BrAC, request that one of these other tests be administered for a more accurate reading. DUIAttorney.com recommends removing your dentures during the 20-minute observation period.
References
- Virginia Department of Forensic Science: Frequently Asked Questions
- The National Association of Criminal Defense Lawyers: The Top 20 Myths of Breath, Blood, and Urine Tests; Leonard R. Stamm; September/October 2005
- DUIAttorney: Georgia Attorney Says Dentures Affect DUI Breath Tests
- PubMed: The Effect of Dentures and Denture Adhesives on Mouth Alcohol Retention
- The Slope Detector; Michael P. Hlastala, Ph.D.
