Musings on Third Molars
TEXOS December 2012 Newsletter
by Larry R. Stewart, DDS, MS
I thought this month that we would talk specifically wisdom teeth and the data concerning third molar removal. There has been a lot of rhetoric on this subject and sometimes it’s nice to see what the “Evidence Base” shows.Much of the data that I present comes from the AAOMS “Task Force on Third Molar Surgery”. The American Association of Oral & Maxillofacial Surgeons undertook third molar clinical trials, which have been continuously funded since 1997. They have collected data on thousands of patients and have been able to generate a landmark study on the topic of “Third molars”.
Some of their findings are as follows:
#1 Up to 60% of asymptomatic patients had evidence of periodontal inflammatory disease as measured by probing depths of at least 4 mm. In asymptomatic adults, 25% had evidence of inflammatory periodontal disease as measured by probing depths of at least 5 mm.
#2 If the first or second molar is carious, there is an 80% chance that third molars will also have carries.
#3, Retained her molars can change positions over time. Up to one third of all unerupted third molars in asymptomatic adults may erupt to the occlusal plane. This does not mean that the tooth is completely visible, functional or hygienic. 75% of these teeth had periodontal pathology.
#4 Approximately 30 to 40% of patients with asymptomatic third molars and no evidence of periodontal disease at baseline, will develop periodontal inflammatory disease around the third molars, as demonstrated by a five year follow-up of this patient group.
#5 Almost 40% of patients with periodontal disease between second and third molars will show clinically significant progression of the process within two years of follow up.
#6 Removal of third molars with periodontal pathology improves the periodontal status on adjacent and on more anterior teeth, whether or not the third molars were symptomatic.
#7 Pregnancy is a significant risk factor for inflammatory periodontal disease around third molars. Greater progression of the disease is seen in patients with erupted third molars and pocket depth of at least 4 mm or bleeding on probing.
#8 Mechanical debridement does not seem to lower levels of pathogenic bacteria or inflammatory mediators around visible third molars. Pregnant subjects having mechanical debridement of biofilm in the second trimester showed that pathogen counts were not decreased postpartum. In a study of healthy adults over a two-year period, dental prophylaxis which included mechanical debridement of biofilm at yearly intervals had minimal to no impact on third molar periodontal pathology.
#9 Even mild pericornitis is a risk factor for periodontal disease around second molars. This is a surprising finding, because older patients tend to be predisposed to periodontal disease and younger patients tend to have more pericornitis episodes.
#10 As might be anticipated, older age, pre-existing periodontal disease and dental caries on adjacent teeth are risk factors associated with development of complications associated with retained third molars.
The study also looked at outcomes after third molar removal and some of the highlights include:
#1 Removal of third molars resulted in a threefold reduction in the proportion of adjacent second molars with periodontal disease, even in previously asymptomatic individuals.
#2 On average, recovery of oral function occurs in five days or less after third molar removal. Bleeding and nausea are minimal and usually limited to the first 48 hours after surgery. Swelling peaks on day two and then resolves quickly. In most patients, pain will steadily decrease over the first five postoperative days but in some patients, pain persisted for up to nine days, requiring oral analgesic medication.
#3 Delayed recovery from third molar surgery was associated with patients over 24 years of age, female gender, and third molars located below the occlusal plane, surgery lasted longer than 30 minutes and in which significant bone was removed to access the tooth. The position of the lower third molar and proximity to the Inferior Alveolar Nerve is a clinical predictor of delays in resuming normal lifestyle, oral function and pain recovery. There was a direct correlation between the patient’s perception of pain and prolonged recovery in terms of lifestyle and oral function.