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Introduction from Editor |
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 Top Introduction from Editor BackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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Background |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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Third molar surgery has been estimated to cost the NHS in
England up to £30 million per year,
2 and approximately £20 million is spent annually in
the private section.
3 Around 90 per cent of patients on waiting lists for oral and
maxillofacial surgery are scheduled for third molar removal.
3
There are wide variations in rates of third molar surgery across the UK.
4,2 There is also some
evidence that deprived populations with poor dental health are less likely to have third molars
removed than more affluent populations with good dental health.
5,2 However, the
reasons for this are complex.
Little controversy surrounds the removal of impacted third molars when they cause pathological
changes and/or severe symptoms, such as `infection, non-restorable carious lesions, cysts,
tumours, and destruction of adjacent teeth and bone'.
6 However, the justification for prophylactic removal of
impacted third molars is less certain and has been debated for many years.
The October 1998 issue of Effectiveness Matters summaries research evidence evaluating the appropriateness of prophylactic removal of impacted third molars.
Several reasons are given for the early removal of asymptomatic or pathology-free impacted third molars, almost all of which are not based on reliable evidence: they have no useful role in the mouth, they may increase the risk of pathological changes and symptoms, and if they are removed only when pathological changes occur, patients may be older and the risk of serious complications after surgery may be greater.
On the other hand, the probability of impacted third molars causing pathological changes in the
future may have been exaggerated.
3,7 Many impacted or
unerupted third molars may eventually erupt normally and many impacted third molars never
cause clinically important problems.
8 In addition, third molar surgery is not risk free; the
complications and suffering following third molar surgery may be considerable.
9 Therefore, prophylactic removal should only be carried
out if there is good evidence of patient benefit.
The proportion of third molar surgery, which is carried out prophylactically in asymptomatic
patients, is difficult to estimate precisely and depends on the definitions used. A UK survey of
181 consultants, found that 35.1 per cent of 25,001 third molars removed were disease free.
10 Other, reliable estimates of prophylactic removal suggest
rates of between 20 to 40 per cent,
11,12,13 though rates as low as 4 per cent have been reported.
14
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Pathological Changes Associated with Impacted Third Molars |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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Pericoronitis (inflammation of the gingiva surrounding the crown of a tooth) is the most common
indication for third molar sugery,
10 and mainly occurs in adolescents and young adults, but
less commonly in older people.
15 A study reported that over 4 years of follow-up, 10 per
cent of lower third molars develop pericoronitis.
16
Very few impacted third molars cause dental caries (decay) of second molars,
15 though estimates vary (1-4.5 per cent).
9 Fear of second molar caries is not a justification for
prophylactic removal.
There is a low incidence (less than 1 per cent) of root resorption of second molars with impacted
third molars.
16,17 One review
concludes that the risk of second molar root resorption by impacted third molars is low and is
likely to occur in younger patients for whom surgery is claimed to be associated with less
morbidity.
15
The association between anterior (front) incisor crowding and impacted third molars is not
significant and does not warrant the removal of third molars.
18,19,20
Cyst development is very rare and is not an indication for prophylactic removal.
15 The risk of malignant neoplasms arising in a dental
follicle is negligible and is not an indication for prophylactic removal.
15
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Complications and Risks Following Surgery |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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Common complications following third molar surgery include sensory nerve damage (paraesthesia), dry socket (dry appearance of the exposed bond in the socket accompanied by severe pain and foul odour), infection, haemorrhage, and pain. Rarer complications include severe trismus, oro-antral fistual, buccal fat herniations, iatrogenic damage to the adjacent second molar, and iatrongic mandibular fracture.
The rate of sensory nerve damage after third molar surgery has been shown to range from 0 to 20
per cent.
9,15,21,22 The overall rate of dry socket
varies from 0 to 35 per cent among studies.
9,23 The risk of dry
socket increases with lack of surgical experience and tobacco use,
24 though this does not justify prophylactic removal.
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Prophylactic Removal: Is It Justified? |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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has concluded that there is little reliable evidence to
support prophylactic removal of impacted third molars. Two decision analyses also concluded
that, on average, patients' longer term well-being is more likely to be maximized if only
those impacted third molars with pathology are removed.
22,25
Two reviews from North America also confirm this conclusion. One acknowledged a lack of
reliable evidence to support the prophylactic removal of impacted third molars.
26 The other concluded that `routine prophylactic
third molar extraction is unjustifiable'.
15 It showed that impacted third molars in adolescents are
most likely to develop pathological indications, while impacted third molars in adults are
unlikely to undergo significant pathological changes. This review also indicated that
`older patients, for whom third molar extraction is necessary, generally tolerate the
procedure well'.
Given the lack of reliable evidence, a general anaesthetic for the removal of a symptomatic third molar should not normally be sufficient justification for removing pathology-free third molars at the same time.
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Risks: pathology versus Surgery |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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the rate of complications after removing third molars was
11.8 per cent in youths (age range 12-29) and 21.5 per cent in older age (age range 25-81). In
addition, results from several studies showed that the risk of pathological changes in older adults
ranges from zero to 12 per cent. Using these figures, it can be calculated that there will be more complications after prophylactic removal of pathology free third molars than after removing only those third molars with pathological changes (see Table 1). For every 100 young people who would undergo prophylactic removal 12 may be expected to suffer from clinically significant complications. Without prophylactic removal, 12 of these 100 people will require surgical removal of third molars at older ages, of whom only three will experience surgical complications.
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Dental surgeons will tend to see (and remember) those patients who experience long-term problems with impacted third molars, rather than patients with no complications. The perceived risk of impacted third molars and the benefits of prophylactic removal will therefore tend to be exaggerated.
Overall, there appears to be little justification for the removal of pathology-free impacted third molars.
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Conclusions |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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Recommendations |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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Acknowledgments |
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References |
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TopIntroduction from EditorBackgroundPathological Changes Associated...Complications and Risks...Prophylactic Removal: Is It...Risks: pathology versus SurgeryConclusionsRecommendationsReferences |
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2 Landes, D. P. The relationship between dental health and variations in the level of third molar removals experienced by populations. Community Dental Health 1998; 15L 67–71.[Medline]
3
Shepherd, J. P., Brickley, M. Surgical removal of third molars. British Medical Journal 1994; 309: 620–621.
4 Toth, B. The Appropriateness of Prophylactic Extraction of Impacted Third Molars. A Review of the Literature. Health Care Evaluation Unit, University of Bristol, 1993.
5 Gilthorpe, M. S., Bedi, R. An exploratory study combining hospital episode statistics with socio-demographic variables, to examine the access and utilisation of hospital oral surgery services. Community Dental Health 1997; 14(4): 209–213.[Medline]
6 NIH. Consensus development conference for removal of third molars. Journal of Oral Surgery 1980; 38: 235-236.
7 Stephens, R. G., Kogon, S. L., Reid, J. A. The unerupted or impacted third molar—a critical appraisal of its pathologic potential. Journal of the Canadian Dental Association 1989; 55(3): 201–207.[Medline]
8 Ahlqwist, M., Grondahl, G. Prevalence of impacted teeth and associated pathology in middle-aged and older Swedish women. Community Dentistry and Oral Epidemiology 1991; 19(2): 116–119.[Medline]
9 Mercier, P., Precious, D. Risks and benefits of removal of impacted third molars. International Journal of Oral and Maxillofacial Surgery 1992; 21: 17–27.[Medline]
10 Worral, S. F., Riden, K., Haskell, R., Corrigan, A. M. UK National Third Molar project: the initial report. British Journal of Oral and Maxillofacial Surgery, 1998; 36(1): 14–18.
11 Lopes, V., Mumenya, R., Feinmann, C., Harris, M. Third molar surgery: an audit of the indications for surgery, post-operative complaints and patient satisfaction. British Journal of Oral and Maxillofacial Surgery 1995; 33: 33–35.
12 Brickley, M., Shepherd, J., Mancini, G. Comparison of clinical treatment decisions with US National Institutes of Health consensus indications for lower third molar removal. British Dental Journal (1993); 185: 102–105.
13
Brickley, M. R., Shepherd, J. P. Performance of a neural network
trained to make third-molar treatment-planning decisions. Medical Decision Making 1996; 16(2): 153–160.
14 Pratt, C. A. M., Hekmat, M., Barnard, J. D. W., Zaki, G. A. Indications for third molar surgery. Journal of the Royal College of Surgeons of Edinburgh 1998; 43(2): 105–108.[Medline]
15 Daley, T. D. Third molar prophylactic extraction: a review and analysis of the literature. General Dentistry 1996; 44(4): 310–320.[Medline]
16 Von Wowern, N., Nielsen, H. O. The fate of impacted lower third molars after the age of 20. A four year clinical follow up. International Journal of Oral and Maxillofacial Surgery 1989; 18(5): 277–280.[Medline]
17 Linqvist, B., Thilander, B. Extraction of third molars in cases of anticipated crowding in the lower jaw. American Journal of Orthodontics 1982; 81(2): 130–139.[Medline]
18 Vasir, N. S., Robinson, R. J. The mandibular third molar and late crowding of the mandibular incisors—a review. British Journal of Orthodontics 1991; 18: 59–66.[Abstract]
19 Song, F., Landes, D. P., Glenny, A. M., Sheldon, T. A. Prophylactic removal of impacted third molars: an assessment of published reviews. British Dental Journal 1997; 182(9): 339–346.[Medline]
20 Harradine, N. W. T., Pearson, M. H., Toth, B. The effect of extraction of third molars on late lower incisor crowding: a randomised controlled trial. British Journal of Orthodontics 1998; 25: 117–122.[Abstract]
21 Carmichael, F. A., McGowan, D. A. Incidence of nerve damage following third molar removal: a West of Scotland Oral Surgery Research Group study. British Journal of Oral and Maxillofacial Surgery 1992; 30(2): 78–82.
22
Brickley, M., Kay, E., Shepherd, J. P., Armstrong, R. A.
Decision analysis for lower-third-molar surgery. Medical Decision Making 1995; 15(2): 143–151.
23 Chiapasco, M., Crescentini, M., Romanoni, G. Germectomy or delayed removal of mandibular impacted third molars: the relationship between age and incidence of complications. Journal of Oral and Maxillofacial Surgery 1995; 53(4): 418–422.[Medline]
24 Larsen, P. E. Alveolar osteitis after surgical removal of impacted mandibular third molars. Identification of the patient at risk Oral Surgery, Oral Medicine, Oral Pathology 1992; 73(4): 393–397.[Medline]
25 Tullock, J. F., Antczak Bouckoms, A. A. Decision analysis in the evaluation of clinical strategies for the management of mandibular third molars. Journal of Dental Education 1987; 51(11): 652–660.[Abstract]
26 ECRI. Removal of third Molars. Executive Briefings, Health Technology Assessment Information Service 1994.
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| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
