Commentary

Dentists are often requested to assist in recommending optimal treatment plans for their patients. The objective of this review was to help the dentist through this process by evaluating and summarising the current literature on the prognosis, preferences and economics of managing an abscessed tooth. The authors systematically review the following four treatment options:

  • save the tooth via RC therapy and then restore it with either a direct or indirect restoration;

  • extract the tooth and leave an edentulous space;

  • extract the tooth and replace it with a FPD; or

  • extract the tooth and replace it with an ISC.

This is the third systematic review published in 2007 that tried to compare the prognosis between these options (Tables 1, 2, 3)1,2 and all of them arrived at similar 5-year prognostic estimates (Table 3). This does demonstrate the soundness of the systematic review methodology in evaluating scientific literature in this discipline.

Table 1 PICO (problem, intervention, comparison outcome) questions.
Table 2 Methods
Table 3 Results

Although this review presents a generally high survival rate, of 6 years or longer, for RC treatment and ISC (in well over 90% of cases), it estimated significantly lower rates for FPD. This led the authors to conclude that ISC and RC treatments resulted in superior longer-term survival than FPD. I suggest caution, however, when interpreting their estimates of longer than 6 years. These “long term survival [rates]” are of limited value since followup time included treatments completed between 7 and 20 years. Ideally, a meta-analysis using the actuarial analysis method described by Lindh et al. (1998),3 would have offered yearly survival estimates carrying greater weight. Such an analysis requires good quality Kaplan-Meyer survival data, though, which may not have been available in many of the studies reviewed.

In addition, the PICO (problem, intervention, comparison outcome) question specified the replacement of a single tooth area, yet the review limited the design and size of the fixed appliance to three- and four-unit bridges, including cantilever bridges. The pooled analysis also included conventional FPD with resin-bonded dentures (‘Maryland bridges’). Such heterogeneity in the treatment design of FPD may explain the wider confidence interval of the estimates compared with the success rate of RC treatment and ISC. (Note that I am referring here to the >6 year success rate estimate and not the survival rate estimate because the latter was taken from a single study of resin-bonded FPD.) Also, the inclusion of resin-bonded dentures probably had a downward effect on the estimated success or survival, as shown by Salinas and Eckert (2007). In that review, excluding resin-bonded FPD from the meta-analysis calculation meant the pooled 5-year survival rate estimated of a conventional FPD was comparable to that of the already high survival estimates for the RC treatment and ISC.

Another limitation of this systematic review is the relatively short time frame of about 6 years, especially when you consider that dental caries is the most common cause of prosthetic failure in the long term.4, 5 Long-term followup studies of 10–20 years may show ISC outperforming the alternatives.

Even though the authors assessed the quality of the studies to be poor to fair, the generally high survival rates (with associated narrow confidence intervals and consistent with the other reviews) for RC treatment, ISC and conventional FPD indicate that the decision on how to manage an abscessed tooth (at least in the 5–6 year timeframe) should be based on factors other than prognosis, namely: prognostic risk factors (smoking, caries activity), patient preferences and economics.

Torabinejad and colleagues tried to determine the specifics of these factors by including psychosocial and economic aspects of each treatment option in their PICO questions. Unfortunately, a limited number of economic studies were found. Furthermore, the various ways psychosocial factors were reported made it impossible to calculate any summary statistic. This indicates that, currently, a void exists in the literature in this area. I am aware of only one study that quantitatively assesses the utility and economics of managing an abscessed tooth through a decision-tree analysis. It concluded that the, “position of the abscessed tooth and the amount of insurance coverage influences the utility and [preference] rank assigned by patients to the different treatment options”.6 Considering the importance of these factors in evidence-based decision-making by the stakeholders in oral healthcare, I suggest that future research resources be directed towards quantitative analysis of the utility and economics of various dental treatment options.

Practice points

In the short term, RC treatment, FPD and ISC have equally high success and survival rates.

The decision on how to manage an abscessed tooth (in the 5–6 year timeframe) should be based on factors other than prognosis, namely prognostic risk factors (medical history, smoking, caries), patient preferences and economics.