Robert Weyant MS, DMD, DrPH
Compared to complete caries removal, partial caries removal leads to less pulp damage and has no effect on caries progression, pulp symptoms, or restoration longevity.
A review considering only the best evidence finds that partial caries removal leads to fewer pulp exposures when treating deep carious lesions.
In deciduous or permanent unfilled teeth, does incomplete (ultraconservative) caries removal result in greater pulpal disease; more progression of decay; or reduced longevity of restorations than complete caries removal?
Five databases (Cochrane Oral Health Trials, Cochrane Central Register, MEDLINE, PubMed, EMBASE) were searched using a published strategy for identifying randomized controlled trials (RCTs). Three authors independently selected studies of clinical trials researching untreated decay that required a filling in a previously unfilled deciduous or permanent tooth. Studies had to report on at least 1 of the following outcomes; a) exposure of the pulp during caries removal; b) patient symptoms of pulpal inflammation or necrosis; c) progression of caries under the filling: or d) time until filling was lost or replaced.
Of 49 full reports reviewed, 4 met the defined criteria. Together, these trials consisted of 339 patients and 538 teeth. Two of these studies involved deciduous teeth and the other 2 involved permanent teeth, with subject ages ranging from 5 to 52 years. In the 2 studies that reported on pulp exposures, the complete caries removal group resulted in pulp exposure in at least 40% of the subjects, while the incomplete removal group experienced no pulp exposures. Pulpal inflammation and necrosis were very rare (4% or less) and generally occurred more often in the complete caries removal group. No restorations were lost or needed replacing after 2 years of follow up.
Partial caries removal was found to greatly reduce the risk of pulp exposure. In symptomless deciduous and permanent teeth, no evidence was found that partial caries removal resulted in any patient detriment from increased pulpal symptoms, decay progression under restorations or premature loss of restorations. Thus, where pupal exposure is a concern, partial caries removal is the preferred approach when treating deep lesions.
Source of Funding:
Internal support from University of Dundee, Guy’s King’s, and St Thomas Dental Schools (UK).
Importance and Context:
There are few procedures more central to the practice of general dentistry than caries removal and the subsequent restoration of teeth. This is thus an important area to consider when understanding optimal approaches to care. This is especially true when also considering the costs associated with treatment failure. This review identified ultraconservative caries removal as the approach that minimizes both initial complications as well as the possible need for additional treatment (e.g., endodontic therapy and additional restorations). As a result, it provides evidence of how simple changes to clinical practice can improve patient outcomes and reduce treatment cost.
Strengths and Weaknesses of the Systematic Review:
The review used established and accepted means to search, select, and extract high quality studies using five appropriate databases. A large number of trials were excluded, seemingly appropriately. Based on AMSTAR criteria, this review was done to a very high standard, failing only to assess publication bias.
Strengths and Weaknesses of the Evidence:
The four studies selected attest to the lack of substantial research in this area. Only two of the studies provided evidence related to pulp exposures. However, they reported large effect sizes, with ultraconservative approaches reducing exposure risk by 98% and 65%, suggesting a real and important finding. There was substantial variability in definitions of partial caries removal and lesion size making it unclear what constitutes an optimal approach. Permanent restorations were limited to composites. Follow up of subjects was relatively short, only one study following subjects for 2 years, however, drop out did not appear to bias the results.
Implications for Dental Practice:
These findings are perhaps counterintuitive and contrary to the approach learned and no doubt practiced by most dentists. The admittedly limited evidence, however, clearly suggests that ultraconservative approaches resulted in no patient detriment and should be considered as an option for deep lesions. What remains to be further determined through more studies with longer follow up is if there is a need to re-enter these lesions and further excavate caries in a stepwise manner. Those studies examining stepwise excavation did not find that need.