An interesting article titled “A Prospective Study of Clinical Outcomes Related to Third Molar Removal or Retention,” appears in the American Journal of Public Health (April 2014, Vol 104, No. 4) written by Greg J. Huang and et al. The article is a companion article to another also on wisdom teeth in the April 2014 issue of the journal. I discussed the companion article last week in the blog post http://blog.teethremoval.com/practice-based-wisdom-teeth-removal-study/.
The article opens by mentioning the controversy surrounding the removal of wisdom teeth. On one side some have advocated for wisdom teeth to be removed to prevent future pathology and minimize risks, others have advocated for wisdom teeth to be removed to prevent lower incisor crowding, and others have argued for wisdom teeth to be removed to prevent periodontal pathology. On the other side some have advocated for wisdom teeth to be retained to avoid complications that can result, with some being lasting and permanent. This study set out to better explore long term outcomes of retaining or removing wisdom teeth by following up with patients over a period of two years.
The methods used for the subjects in the study were the same as in the previous companion article. The researchers noted several things from their study. For the 517 participants with follow-up data, a total of 316 (61%) retained all existing wisdom teeth during follow-up. Among the 218 study participants who returned for the final examination, a general trend toward continued eruption of the wisdom teeth occurred. At final clinical examination, a total of 26% of the of the retained wisdom teeth were partially or fully erupted.
During follow up, the incidence of self reported TMJ clicking or popping was not significantly different between participants who did and did not have wisdom teeth extracted. However, the rates of TMD (which is jaw pain on wide opening and pain in the temples, jaw joint, or jaw muscles) was significantly higher after wisdom teeth extraction when compared to those who did not have wisdom teeth extracted. Furthermore, the incidence of self reported lip and tongue paresthesia was higher in those who had wisdom teeth extracted (5.8 and 4.2 in 100 person years) than those who retained wisdom teeth (0.4 and 0.5 in 100 person years).
The study found that the incident dental caries on the distal surface of the second molars was 0.2 per 100 surface years for those teeth adjacent to extracted wisdom teeth and it was 0.6 per 100 surface years for those second molars next to retained wisdom teeth.
In the discussion the authors state
“Paresthesia has been reported to occur in about 1% to 5% of patients …in our study (about 6%) is not far from the upper bounds of past reports.”
The authors later state
“Our charge, as dentists, is to thoroughly assess a patient’s unique circumstances, to educate our patients on their condition, to utilize the existing evidence, and to provide our best advice and care for the management of their particular oral condition. Third-molar decisions should be no different.”
The main conclusions from the study are as follows:
1) The rates of paresthesia and TMD symptoms were significantly higher for patients who had wisdom teeth extracted where in some cases the effects were long lasting.
2. The average rate of attachment loss at distal sites of second molars was minimal over a 2 year period and it did not matter if a wisdom tooth was retained or extracted.
3. The incidence of caries on the distal surface of the second molars was less than 1% while for wisdom teeth the caries rate was approximately 3.3% on the occlusal surfaces.
4. Considerable eruption of wisdom teeth occurred during the 2 year monitoring period with those wisdom teeth were retained.