Subjective versus objective, polymer bur-based selective carious tissue removal: 2-year randomized clinical trial.

Objectives: We aimed to compare subjective (S) selective carious tissue removal using hand instruments versus objective (O) removal using a self-limiting polymer bur in a single-blind cluster-randomized controlled superiority trial.

Methods: 115 children (aged 7-8 years) with ≥1 vital primary molar with a deep dentin lesion (>1/2 dentin depth) were included and randomized (60 S/55 O); all eligible molars in a child were treated identically (91 S/86 O). Cavities were prepared and carious tissue on pulpal walls selectively removed using hand instruments (S) or a self-limiting polymer bur (Polybur P1, Komet), followed by restoration using a glass hybrid material (Equia Forte, GC). Treatment time and satisfaction data have been reported in a 1-year-interim report. We here report on 2 year survival (tooth retained with or without further retreatments being needed, or tooth exfoliated), analyzed using multi-level Cox-regression analysis, as well as success (ART criteria 0/1, no pulpal complications, no re-intervention needed, or tooth extraction).

Results: 71 restorations in S and 65 in O were examined after a mean (SD, range) of 22 (11; 3-31) months, of which 50 S and 48 O restorations were successful and 70 S and 65 O survived. The majority of failures were restorative, not pulpal, and distribution of ART codes was not significant different between groups. Risk of failure was not significantly associated with the removal protocol (HR; 95 % CI: 0.95; 0.51-1.78), and also not age, sex or dental arch, while single surfaced restorations showed significantly lower hazard (0.14; 0.06-0.37).

Conclusion: There was no significant difference in success or survival between objective and subjective carious tissue removal.

Clinical Significance: In primary teeth, subjective selective excavation had no disadvantage compared with objective excavation, which required a separate instrument (polymer-based bur) for carious tissue removal. Polymer-based burs may be particularly useful when standardized excavation is needed.