The aim of the current study was to investigate whether there was a relationship between a history of third molar removal and the prevalence of orofacial pain in a sample of the general population.
A survey was conducted in South East Cheshire, United Kingdom (81% participation rate). Information was collected using postal questionnaires (n = 1510) and dental records (n = 809).
Participants who reported third molar extractions were more likely to report orofacial pain (RR = 1.29; 95% confidence interval [CI] 1.01 - 1.65). Participants with a more recent history of extractions (< 8 years ago) as recorded in dental records were more likely to report orofacial pain compared to those who had all third molar present (RR = 1.91; 95% CI 1.10 - 3.32).
This research suggests that self-reported third molar removal is linked to self-reported orofacial pain, however evidence from one study is not sufficient to give an unequivocal answer.
Orofacial pain (OFP) includes pains whose origin is below the orbitomeatal line,
above the neck and anterior to the ears and pain within the mouth [
It has been suggested that there is a relationship between the removal of third
molars and the postoperative onset of temporomandibular joint pain/dysfunction. As
early as 1969, Greene et al. [
The aim of the current study was to investigate whether there was a relationship between a history of third molar removal and the prevalence of orofacial pain in a sample of the general population.
The study was a four year follow-up of the population survey conducted by Macfarlane
et al. [
Ethical approval for the study was granted by South Cheshire Local Research Ethics Committee.
Sample size for the baseline survey was calculated using the results of a pilot study
using OFP prevalence estimate of 25% [
Each participant received a postal questionnaire, with follow-up of non-responders by
a reminder postcard, questionnaire and, if necessary, a short questionnaire and a
telephone call. The questionnaire consisted of demographic, psychological, body pain
and OFP sections. OFP was defined as present if participants during the past month
"had any pain in their face, mouth or jaws that has lasted for one day or
longer". Body pain was defined as present if participants during the past month
"had any ache or pain in the body which has lasted for one day or longer".
Psychological distress was measured using the 12-item version of the General Health
Questionnaire [
Participants were also asked if they had their wisdom teeth removed and permission to be contacted again. In addition, participants were asked permission for their dental records to be examined, and in case of positive reply, were asked to indicate the name and address of their dentist.
Information from dental records was extracted by one of two clinical examiners. Information regarding number, position and method of third molar removal was recorded. Data were extracted in duplicate (both clinical examiners) from 10 records to investigate reliability. One clinical examiner repeated data extraction from 10 dental records twice to investigate reproducibility.
The magnitude of association between third molar removal and OFP was described by the
relative risk (RR). RR here is a measure of the risk of OFP in one group compared to
the risk of OFP in another (reference) group. A relative risk of one means there is
no difference between two groups in terms of their risk of OFP. A relative risk of
greater than one or of less than one means that being exposed to a factor either
increases (relative risk greater than one) or decreases (relative risk less than
one) the risk of OFP. Cox regression [
A total of 1680 persons (81% adjusted participation rate after excluding those who were no longer registered with the practice, deceased or who were not able to complete the questionnaire due to illness or disability or expressed a wish at baseline not to be contacted again) participated in the follow-up survey, and the full study questionnaire was completed by 1510 participants. The remainder completed a short version of the questionnaire which did not include question on third molar removal.
Adjusted participation rate was higher in women (83%) compared to men (77%) (Chi-square test P < 0.001) and in affluent areas (83%) compared to deprived areas (59%) (Chi-square test P < 0.001). Non-respondents were older (mean age 49 years [SD = 12]) then non-respondents (mean age 44 years [SD = 13]) (t-test P < 0.001).
Of those who completed the full questionnaire, 295 (19%) reported OFP, 1202 (80%) did not report such pain and 13 (1%) did not answer this question. Majority (60%) of self-reported OFP was chronic, i.e. lasted for more than 3 months. The mean pain severity was 4.8 on 10-point numerical analogues scale (SD = 2.3) and 62% sought advice on OFP from a health professional.
Over half (873, 58%) of respondents did not report a history of perceived third molar extractions, 77 (5%) did not answer this question, giving 560 (37%) who reported third molar removal.
The majority of participants (1060, 70%) who completed the full questionnaire gave permission for their dental records to be examined, and indicated the name and address of their dentist. Eight hundred and sixty (81%) participants were registered with four main dental practices in the study area; the remainder were registered with dentists in the surrounding areas. These distant practices were not visited, so only these four main practices were included, and 806 (94%) patient records were found. In addition, one practice in the surrounding area with 3 patient records was used as a pilot site, giving total of 809 records. Median time of registration with a dentist was 14 years (range 1 day - 46 years) prior to completing the questionnaire.
There was an acceptable (Cohen's kappa > 0.6, P < 0.05) agreement when
reliability and reproducibility of information regarding third molars extracted from
dental records. The minimum Cohen's kappa value was 0.61, maximum 1.00, median was
0.71, indicating at least substantial agreement, according to classification by
Landis and Koch [
To validate the answers in the questionnaire regarding perceived third molar removal,
this question was cross tabulated against the extractions recorded by dentists
(
Validity of self-reported third molar extractions
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At least one third molar missing, |
At least one third molar extraction | All four third molars present | Total | |
Third molars not removed | 314 (69.2) | 27 (6.0) | 113 (24.8) | 454 (100) |
Third molars removed | 193 (59.9) | 20 (37.3) | 9 (2.8) | 222 (100) |
aInformation was missing for 33 participants.
Participants who reported third molar extractions in the questionnaire were more
likely to report OFP (adjusted Relative Risk [RR] 1.29); (95% confidence interval
[CI] 1.01 - 1.65) (
Relationship between third molar extractions and orofacial pain (OFP)
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Third molars not removed | 866 | 17.4 | 1.00 | 1.00 |
Third molars removed | 556 | 22.8 | 1.38 (1.08 - 1.76) | 1.29 (1.01 - 1.65) |
Missing data | 88 | |||
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All third molars present | 130 | 19.2 | 1.00 | 1.00 |
At least one third molar extracted | 151 | 27.8 | 1.50 (0.91 - 2.48) | 1.50 (0.90 - 2.49) |
No information on extraction in record or missing questionnaire data | 528 | |||
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All third molars present | 130 | 19.2 | 1.00 | 1.00 |
Extraction 2 - 99 months agoa | 72 | 37.5 | 1.95 (1.12 - 3.37) | 1.91 (1.10 - 3.32) |
Extraction 100 - 558 months ago | 73 | 17.8 | 0.99 (0.50 - 1.95) | 1.07 (0.54 - 2.13) |
No information on date of extraction | 6 | |||
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All 4 present | 130 | 19.2 | 1.00 | 1.00 |
3 | 112 | 22.3 | 1.27 (0.73 - 2.21) | 1.24 (0.71 - 2.16) |
2 | 145 | 20.7 | 1.13 (0.66 - 1.93) | 1.03 (0.60 - 1.78) |
1 | 139 | 23.0 | 1.32 (0.83 - 2.11) | 1.29 (0.76 - 2.20) |
All absent | 252 | 24.6 | 0.96 (0.63 - 1.45) | 1.19 (0.74 - 1.90) |
Information missing on at least one third molar | 28 | |||
No information on OFP | 3 |
a100 months was a median time since extraction and therefore was chosen as a cut-off point. No participants had extraction less than 2 month prior to questionnaire completion.
This population-based epidemiological study has provided evidence that individuals who report third molar extractions are more likely to report OFP. When extraction information was validated using dental records, this association was only found in relatively recent extractions.
Any dental intervention that alters the occlusion has the potential to alter the
position of the mandibular condyle in the mandibular (glenoid) fossa and predispose
to TMD symptoms [
There are methodological issues which need to be considered when examining the study results.
The study involves a sample of the population of one geographic area in the United Kingdom and therefore may not be representative. While the overall participation rate at follow-up was high, non-participants were more likely to be male, younger and from lower socio-economic background.
Nevertheless, these differences would only affect the comparisons in the present study if the relationship between these factors and presence of OFP were different in those subjects who participated compared with those who did not. This seems unlikely.
All possible efforts were made to increase the participation. Questionnaires were posted together with a covering letter from the general medical practitioner informing practice members of the practice participation in the study. A reply paid envelope was enclosed. Posters about the study were placed in the medical practice. Non-respondents were followed up by a postcard reminder, a further questionnaire, and, if necessary, a short questionnaire and a telephone call.
Although there was a statistically significant increase in risk (30%) of OFP
associated with self-reported extractions, we did not find a statistically
significant association between at least one third molar extraction determined from
the dental records and OFP (50% increased risk). Firstly, there was less statistical
power when information from dental records was analysed, as not all participants who
completed the questionnaire had information from dental records. Secondly,
individual perception may play role in this discrepancy. However we have adjusted in
the statistical analysis in both cases for other potential risk factors such as
other body pain and psychological distress. Thirdly, it has been shown that that
there was good correspondence between subjective self-reports of well-defined oral
health conditions and clinical findings, for example the number of teeth and the
presence of dentures [
While the study has achieved high participation rate and acceptable reliability when extracting information from dental records, several problems were encountered. Although participants had reported third molar removal in the original questionnaire, it may not be entirely accurate. For approximately half of all cases, third molars were marked as absent in the records but with no record of extraction. It was impossible to determine from the notes whether third molars marked as absent in this way were: 1) congenitally absent; 2) unerupted; 3) had been extracted before the origin of the notes. This problem was accentuated in the older age groups, where early dental records were not available. Another issue was inconsistent charting of third molars. In rare cases it was obvious that after early extraction of first molars, third molars were being recorded. In some cases charting of the tooth could change several times throughout the notes. Better recording of dental notes would help resolve some of these problems in primary dental care research. In addition, this study is a cross-sectional survey and therefore the associations we report are not necessarily causal.
This research has shown that there is a weak relationship between self-reported history of third molar removal and self-reported orofacial pain, and the depth and detail of evidence is still inconclusive.
The authors are grateful to staff and patients of Lawton House Surgery, dental practice of AR Mellor & Associates, Canal Street Dental Practice, Moody Terrace Dental Practice and TDU Miller dental practice in Congleton, Cheshire, United Kingdom for their help with the study. We are also grateful to Dr. D. King, University of Manchester, Manchester, UK and Mrs. C. Mackie, Manchester Dental School, Manchester, UK, for help with access to dental records.
The authors report no conflicts of interest related to this study.