The cost, effectiveness and cost effectivenes of removal and retention of asymptomatic, disease free third molars

ABSTRACT PURPOSE OF INVESTIGATION The study was undertaken to identify the least costly, most effective and most cost-effective management strategy for asymptomatic, disease free mandibular

third molars. METHODS AND PATIENTS A decision tree model of the outcomes of mandibular third molar retention and removal was constructed. Probability data for possible outcomes were obtained

from a comprehensive literature review and entered into the decision tree. The cost to the NHS in treating each outcome was calculated. 100 patients attending the oral surgery clinics,

University of Wales Dental Hospital rated the effect of each outcome on their own life. The cost and effectiveness data for each outcome were entered into the decision tree and the analyses

were conducted by 'folding back' the decision tree based on the probabilities. MAIN FINDINGS Mandibular third molar retention was less costly (£170), more effective (69.5

effectiveness units on a 100 point scale) and more cost-effective (£2.43 per unit of effectiveness) than removal (£226, 63.3 and £3.57 respectively). These findings were sensitive to changes

in the probability of pericoronitis, periodontal disease and caries. PRINCIPAL CONCLUSIONS Mandibular third molar retention is less costly to the NHS, more effective for the patient and

more cost-effective to both parties than removal. However, should the likelihood of developing pericoronitis, periodontal disease and caries increase substantially then removal becomes the

more cost-effective strategy. You have full access to this article via your institution. Download PDF SIMILAR CONTENT BEING VIEWED BY OTHERS HISTORICAL ASPECTS ABOUT THIRD MOLAR REMOVAL

VERSUS RETENTION AND DISTAL SURFACE CARIES IN THE SECOND MANDIBULAR MOLAR ADJACENT TO IMPACTED THIRD MOLARS Article 24 February 2023 HALL TECHNIQUE: IS IT SUPERIOR IN SUCCESS AND SAVINGS TO

CONVENTIONAL RESTORATIONS? Article 18 December 2020 PATIENT PREFERENCE FOR THE MANAGEMENT OF MANDIBULAR THIRD MOLARS WITH MESIO-ANGULAR AND HORIZONTAL IMPACTIONS Article 07 February 2025

MAIN The indications for the removal of mandibular third molars have been the subject of a great deal of debate. In the past, many dentists and surgeons have recommended that asymptomatic

mandibular third molars should be removed to prevent future disease.1,2,3 Many others have expressed the opposite view. Published reviews of the risks and benefits of mandibular third molar

management have concluded that prophylactic removal is unjustified.4,5 Decision and cost-effectiveness analyses have strongly supported the appropriateness of retention of asymptomatic,

disease free third molars.6,7,8 However, these studies have rarely taken account of the patients' perspective or health service costs. As health care evolves towards a patient-centred

service, it is increasingly important to consider the patient's perspective in health care decisions.9 Additionally, decisions must be made concerning the maximisation of effective

resource allocation. A method of quantifying the relative costs, effectiveness and cost-effectiveness of particular treatment options is decision analysis. This method depends on clinical

knowledge (probability of outcomes) and values attached to different outcomes (patient utilities and health service cost). It permits both objective data and subjective personal preferences

to play a part in the decision process. This is consistent with how medical decisions are actually made.10 Decision analysis was first described more than three decades ago.11 It arose from

the disciplines of economics, statistics, and psychology and in the case of clinical decision analysis, epidemiology and clinical informatics. Since the 1970s, decision analysis has

increasingly been applied to complex medical decisions12 in clinical, financial and research settings.13 The increased use of decision analysis in medicine and dentistry6,8 possibly reflects

the increasing importance of economic costs and quality of health care provision. Tulloch _et al_. have stated that 'Although performing a detailed analysis for every mandibular third

molar management decision may appear complex and time-consuming, an analysis of well-defined outcomes that occur frequently and where there are both uncertainties and risks would be

useful'.19 This study is based on this recommendation, a decision analysis was conducted to identify the least costly, most effective and most cost-effective management strategy for

asymptomatic, disease-free third molars from both the health care provider and patient perspective. METHOD The construction of the decision tree and determination of the probability, cost

and effectiveness data was carried out in phases. PHASE 1 CONSTRUCTION OF THE DECISION TREE AND DETERMINATION OF THE PROBABILITY DATA. The various outcomes of lower third molar retention and

removal, together with their incidences were obtained from a comprehensive computerised (Medline) and manual search of the medical literature (1966 to 1998). The detailed outcomes were

structured within their own sub-trees, for example with or without pain (Appendix 1). The probability of each outcome was the mean incidence reported from all of the relevant literature. The

rates were expressed as a proportion of one relative to the other outcomes within the sub-tree. Collectively, this information formed the basis of the decision tree, which was constructed

using decision analysis software20 (Appendix 1). The decision tree did not include an analysis of differences in surgical morbidity with age or changes in increase of disease with age.

Evidence available in relation to these issues is scarce, but such evidence as is available suggests that surgical morbidity does not increase with age.21 Therefore, these values were not

incorporated into the decision analysis. PHASE 2: DETERMINATION OF COST DATA Cost was measured in terms of direct economic cost in an NHS hospital and incorporated consumables, staff costs,

overheads and equivalent annual costs. The strategy used to calculate these can be seen in Appendix 2. The costs for third molar removal (including anaesthetic costs) and retention were

calculated to obtain a total cost given a particular outcome (Tables 1 and 2). PHASE 3: DETERMINATION OF EFFECTIVENESS DATA Effectiveness data were obtained using a questionnaire adapted and

modified from research conducted by Armstrong _et al_.22 The questionnaire consisted of twenty-two scenarios, describing in everyday language all of the various outcomes identified in the

literature, for example 'A wisdom tooth erupts at the back of your mouth. Every six weeks or so you experience a few days of aching pain around the tooth and the gum feels

swollen', and 'After the extraction you experience pain and your face and mouth are swollen'. Fourteen of the scenarios represented the possible health outcomes following

third molar removal (Table 1) and eight scenarios represented the outcomes of retention (Table 2). Accompanying each scenario was a VAS, 100mm in length. The end points of the VAS were

'Things could not be worse' (0mm) and 'I would not be bothered at all' (100mm). One hundred and two consecutive patients were invited to rate the outcomes after they had

completed a consultation in the oral surgery clinic, University of Wales Dental Hospital; however, two refused due to lack of time. As part of normal treatment planning, patients had been

informed of all the possible outcomes of removal by the clinician. In addition, to standardise this information, an information leaflet23 was given to the patient to read at the end of the

consultation. Before completing the questionnaire, the patients were asked to read each of the scenarios. This allowed them to become familiarised with the scope of outcomes. Each patient

then re-read the scenarios and placed a cross on the VAS at a point they felt represented how they would feel if they experienced each of the scenarios. The patients were allowed as much

time as they required to complete the questionnaire. The cross made by each patient on the VAS for each scenario was measured to the nearest millimetre and constituted the measure of

effectiveness. The mean effectiveness scores were then calculated (Table 3). PHASE 4: DECISION ANALYSIS NHS procedure costs and mean effectiveness scores were entered into their respective

terminal nodes, or outcomes on the tree. Collectively, these values were 'folded back'. This is a decision analysis procedure that takes into consideration the probability of each

outcome when determining the average cost, effectiveness and cost-effectiveness of mandibular third molar retention and removal. In addition, the various values were subjected to sensitivity

analyses, which allowed the investigation of how changes to the various values could alter the most cost-effective strategy. RESULTS The National Health Service procedure cost of outcomes

following mandibular third molar management is shown in Tables 1 and 2 and Appendix 3. The average National Health Service procedure cost for mandibular third molar retention (£170) was less

than surgical removal (£226) resulting in a marginal cost of £56 (Table 4). The effectiveness of mandibular third molar management was rated as being greater for third molar retention

(69.5) than for removal (63.3) giving a marginal effectiveness of -6.2 (Table 4). Taking into consideration both the costs and effects, mandibular third molar retention (£2.43 per unit of

effectiveness) was more cost-effective than removal (£3.57 per unit of effectiveness). It thus follows that the strategy of removal was less cost effective over the whole range of cost

compared with the strategy of third molar retention (Table 4). Sensitivity analyses revealed that the model was only sensitive to alteration of the probability values for pericoronitis,

periodontal disease and unrestorable caries in the second molar. They had threshold values of 0.40, 0.17 and 0.22, respectively. The threshold values indicate the point at which the most

cost-effective strategy for an asymptomatic mandibular third molar would alter from retention to removal. For example, if for a particular third molar, the probability of developing

pericoronitis exceeded 40% then it would be more cost effective to remove the tooth than to adopt a conservative approach. DISCUSSION AND CONCLUSIONS Cost, effectiveness and

cost-effectiveness analyses indicated that third molar retention was less costly to the NHS within the Hospital Dental Service, more effective for the patient and more cost-effective than

removal. Although the costs are specific to the HDS, these findings support the findings of previous research suggesting that third molar retention is the optimal management for

asymptomatic, disease free mandibular third molars.4,5,6,7,8 It is appropriate to consider the extent to which these results would translate to general practice where different costs would

apply. Potentially, more efficient cost control in practice might make the surgical treatment of patients with mild low grade disease more appropriate. However, the optimal treatment for

pathology free teeth would not alter since, on clinical grounds alone, they are best treated conservatively. The findings also suggest that there is only a cost saving or health gain in

removing asymptomatic, pathology-free mandibular third molars when there is a substantially increased risk of developing pericoronitis, periodontal disease and caries. Should the chance of a

patient developing one of these three diseases be greater than the threshold value identified in this study then removal becomes the more cost-effective strategy. Certain populations are at

greater risk of developing pericoronitis/periodontal diseases such as smokers.23,24 An additional concern is that the probability values used for this study may be underestimated. The range

of reported incidences in the literature suggests that this is possible in some patient groups as the maximum reported probabilities compare with the probabilities that would change the

optimal strategy.25,26,27,28,29 The conclusions drawn from decision analyses depend upon the quality of the information upon which they are based. In this instance, the sources of

probability data were of concern as there was a wide range of reported incidences for each outcome suggesting that there were both variations in methodology and biases in results. Ideally,

randomised-controlled trials or prospective, longitudinal research needs to be conducted to provide evidence that is more conclusive. The benefit of incorporating NHS cost and patient

perceived effects when evaluating mandibular third molar management options is that resources can be apportioned so that treatment that does not yield a health gain can be avoided.8 Cost and

effectiveness data collection is straightforward. This would facilitate analyses on a national basis and across various clinical settings. This type of analysis also provides a clearer

insight into the economic implications of high volume, high cost procedures, where small changes in treatment may result in large gains in terms of financial and opportunity cost. This study

has highlighted the dynamics of decision making in relation to one high volume surgical procedure. The apparent similarities between the perceived and economic impact of mandibular third

molar management options implies that there is some agreement between the patient and the NHS when it comes to developing appropriate criteria for treatment interventions. The likelihood of

developing pericoronitis, periodontal disease and unrestorable caries are the only factors that may challenge the philosophy that prophylactic removal should be avoided. Until more knowledge

is gained about the risks of developing these, non-surgical management of asymptomatic mandibular third molars remains the most cost-effective strategy for the NHS. REFERENCES * Laskin D M

. Indications and Contraindications for Removal of Impacted Third Molars. _Dent Clin North Am_ 1969; 13: 919–28. PubMed  Google Scholar  * Laskin D . Evaluation of the third molar problem.

_J Am Dent Assoc_ 1971; 82: 824–9. Article  Google Scholar  * Hopkins R . Third molars may cause severe problems in middle age (Letter). _Br Dent J_ 1994; 309: 1301. Google Scholar  * Song

F, Landes D P, Glenny A, Sheldon T A . Prophylactic removal of impacted third molars: an assessment of published reviews. _Br Dent J_ 1997; 182: 339–46. Article  Google Scholar  * Toth B.

1993 _The appropriateness of prophylactic extraction of impacted lower third molars_. Bristol, UK; University of Bristol. Google Scholar  * Tulloch J F, Antczak-Bouckoms A A . Decision

analysis in the evaluation of clinical strategies for the management of mandibular third molars. _J Dent Educ_ 1987; 51: 652–60. PubMed  Google Scholar  * Tulloch J F, Antczak-Bouckoms A A,

Wilkes J W . The application of decision analysis to evaluate the need for extraction of asymptomatic third molars. _J Oral Maxillofac Surg_ 1987; 45: 855–65. Article  Google Scholar  *

Brickley M R, Kay E J, Shepherd J P, and Armstrong R A . Decision Analysis for Lower-third molar Surgery. _Med Decis Making_ 1995; 15: 143–151. Article  Google Scholar  * Brickley M R,

Armstrong R A, Shepherd J P, and Kay E J . The relevance of health state utilities to lower third molar surgery. _Int Dent J_ 1995; 45: 124–128. PubMed  Google Scholar  * Elstein A S,

Dawson-Saunders B, Belzer L J . Instruction in medical decision making. A report of two surveys. _Med Decis Making_ 1985; 5: 229–33. Article  Google Scholar  * Ledley R S, Lusted L B .

Reasoning foundations of medical diagnosis. _Md Computing_ 1991; 8: 300–315. PubMed  Google Scholar  * Hagen M D . Decision analysis: a review. _Family Medicine_ 1992; 24: 349–54. PubMed 

Google Scholar  * Pauker S G, Kassirer J P . Decision analysis. _New Engl J Med_ 1987; 316: 250–8. Article  Google Scholar  * McCreery A M, Truelove E . Decision making in dentistry. part i:

a historical and methodological overview. _J Prosthet Dent_ 1991; 65: 447–51. Article  Google Scholar  * McCreery A M, Truelove E . Decision making in dentistry. part ii: clinical

applications of decision methods. _J Prosthet Dent_ 1991; 65: 575–85. Article  Google Scholar  * Stockstill J W, Bowley J F, Attanasio R . Clinical decision analysis in fixed prosthodontics.

_Dent Clin North Am_ 1992; 36: 569–80. PubMed  Google Scholar  * Zarb G A, Lewis D W . Evaluation of the clinical decisions analysis in fixed prosthodontics. _Archives of Pathology &

Laboratory_ 1992; 112: 383–6. Google Scholar  * Mohl N D, Ohrbach R . Clinical decision making for temporomandibular disorders. _J Dent Educ_ 1992; 56: 823–33. PubMed  Google Scholar  *

Tulloch J F C, Antczak-Boukoms A A, Ung N . Evaluation of the costs and relative effectiveness of alternative strategies for the removal of mandibular third molars. _Int J of tech assess in

health care_ 1990; 6: 505–15. Article  Google Scholar  * _Decisions Analysis by Tree Age_ (1988) Treeage Software 2. 6.6 IBM PC. Windows 3.5 floppy. * Chaipasco M, Crescentini M and 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:

418–22. Article  Google Scholar  * Armstrong R A, Brickley M R, Shepherd J P, and Kay E J . Healthy decision making: a new approach in health promotion using health state utilities.

_Community Dent Health_ 1995; 12: 8–11. PubMed  Google Scholar  * Bruce R A, Fredickson G C, and Small G S . Age of patients and morbidity associated with mandibular third molar surgery. _J

Am Dent Assoc_ 1980; 101: 240–245. Article  Google Scholar  * Lysell L. and Rohlin M . A study of indications used for removal of the mandibular third molar. _Int J Oral Maxillofac Surg_

1988; 17: 161–164. Article  Google Scholar  * Stanley H R, Alattar M, Collett W K, Stringfellow H R . Pathological sequlae of neglected impacted third molars. _J Oral Pathol Med_ 1988: 123;

113–117. Article  Google Scholar  * Van deb Linden W, Cleaton-Jones O, Lownie M . Diseases and lesions associated with third molars. _Oral Surgery Oral Medicine Oral Pathology_ 1995: 79:

142–145. Article  Google Scholar  * Lopes V, Mumenya C, Feinmann M H . Third molar surgery: an audit of the indications for surgery, post-operative complaints and patient satisfaction. _Br J

Oral Maxillofac Surg_ 1995; 33: 33–35. Article  Google Scholar  * Ong G . Periodontal disease and tooth loss. _Int Dent J_ 1998; 48: 233–8. Article  Google Scholar  * Tonetti M S .

Cigarette smoking and periodontal diseases: etiology and management of disease. _Annals of Periodontology_ 1998; 3: 88–101. Article  Google Scholar  Download references AUTHOR INFORMATION

AUTHORS AND AFFILIATIONS * Department of Oral Surgery, Clinical Decisions Research Group, Medicine and Pathology, University of Wales College of Medicine Dental School, Heath Park, CF4 4XY,

Cardiff Michelle J Edwards, Mark R Brickley, Rebecca D Goodey & Jonathan P Shepherd Authors * Michelle J Edwards View author publications You can also search for this author inPubMed 

Google Scholar * Mark R Brickley View author publications You can also search for this author inPubMed Google Scholar * Rebecca D Goodey View author publications You can also search for this

author inPubMed Google Scholar * Jonathan P Shepherd View author publications You can also search for this author inPubMed Google Scholar ADDITIONAL INFORMATION REFEREED PAPER APPENDICES

APPENDIX 1 APPENDIX 2 APPENDIX 3 RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Edwards, M., Brickley, M., Goodey, R. _et al._ The cost, effectiveness

and cost effectivenes of removal and retention of asymptomatic, disease free third molars. _Br Dent J_ 187, 380–384 (1999). https://doi.org/10.1038/sj.bdj.4800285 Download citation *

Received: 14 January 1999 * Accepted: 23 July 1999 * Published: 09 October 1999 * Issue Date: 09 October 1999 * DOI: https://doi.org/10.1038/sj.bdj.4800285 SHARE THIS ARTICLE Anyone you

share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the

Springer Nature SharedIt content-sharing initiative