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How Gingivitis and Periodontal Disease Affects Breath Alcohol Testing

Breath Machines in DUI cases operate on the assumption that the machine is measuring alcohol in deep lung air. A problem may arise if alcohol from a different source is introduced into the breath machine. One example would be a burp or belch, so that the machine reads alcohol in the air coming from the stomach instead of alveolar air. There are certain safeguards in place to make sure that the breath machine is reading alcohol from the subjects lungs. Firstly, two breath samples are taken that must be between .02% of each other for quality control purposes. Secondly, there must be a continuous observation period of the subject for at least fifteen minutes before blowing into a machine to make sure that the person does not vomit, belch or ingest anything during that time frame. Lastly, some breath machines have a slope detector which is a device intended to make sure that the machine measures only alcohol coming from deep lung air.

Gingivitis or Periodontal disease presents a difficult problem in breath alcohol testing. Gingivitis can be described as “bleeding gums”. Periodontal disease results in pockets around the teeth that may contain alcohol, food or blood. The problem is that this “trapped mouth alcohol” may not be recognised by a slope detector, because of its continuing presence over time. In addition, duplicate analyses and a fifteen minute observation period may not safeguard against trapped mouth alcohol because it is consistently present as opposed to dissipating like alcohol in a burp.

In addition, a person suffering from these dental issues may “blow” small quantities of blood into the breath testing chamber. Alcohol in this blood may significantly inflate the breath alcohol results.

In presenting a defense based on the above medical conditions, it is necessary for any DUI Defense Attorney to secure the testimony of a Periodontist and a Breath or Blood Alcohol Expert or Toxicologist. Care must be taken to also address the other evidence of impairment in the case, such as the driving pattern, performance of field sobriety tests and any objective symptoms of mental or physical impairment. A jury must also be convinced that the defendant was not impaired to drive as well as beating the breath alcohol readings.