# Immediate or delayed direct restoration does not significantly influence additional endodontic treatments and 5-year tooth survival of first molars

## TL;DR

This study found that the timing of placing a direct restoration after a root canal treatment does not significantly affect the long-term success of first molars.

## Contribution

The study provides clinical evidence that immediate or delayed direct restoration after root canal treatment does not influence 5-year tooth survival or need for additional treatments.

## Key findings

- No significant time-dependent differences were found in orthograde retreatment registrations.
- The time elapsed between root canal treatment and restoration placement did not affect 5-year tooth survival.
- Extractions and apical surgeries were not significantly influenced by restoration timing.

## Abstract

In vitro leakage studies suggest that temporary restorations only provide a short-term seal. However, it remains unclear whether the clinical outcome is impacted by the time elapsing between the completion of a root canal treatment (RCT) and the placement of a direct permanent coronal restoration. The aim was to investigate any time-dependent difference in frequencies of endodontic orthograde retreatment, apical surgery and extractions during the subsequent 5 years following root filling of first molars restored with a direct restoration depending on immediate or delayed time between completion of RCT and placement of a direct restoration.

Data from the Swedish Social Insurance Agency was collected. In 2009, 50,314 direct restorations were registered after RCT of the first molars in individuals aged 20 years or older. The teeth were divided into five time intervals depending on time from completion of root filling to placement of direct restoration for comparisons of frequencies of orthograde retreatment, apical surgery and extractions, during the following 5 years.

The time interval categories were compared using Pearson’s Chi-square test.

No statistically significant time-dependent differences in registrations were found for orthograde retreatment (p = 0.089), with or without apical surgery (p = 0.161) and with or without extraction (p = 0.737).

The time elapsed from the completion of RCT and the placement of a direct restoration did not affect the 5-year outcome of the RCT.