Larger apical preparation sizes may Raise Post-operative Pain during root canal treatment, finds study

The study, published in BMC Oral Health, revealed that larger apical preparation sizes during root canal treatments significantly raise postoperative pain.

Highlighting the impact of various apical preparation sizes on postoperative pain is crucial, especially when considering patients with identical pulpal histological statuses. Considering this, Mohammed Abou el Seoud, Department of Endodontics, Faculty of Dentistry, The British University of Egypt, Cairo, Egypt, and colleagues aimed to compare and evaluate the severity of postoperative pain following apical enlargement with two different sizes after the initial binding file (IBF) using the visual analog scale.

For this purpose, the researchers enrolled fifty “teeth” in 25 patients. They were assigned into two equal groups comprising 25 per group, using E3 Azure rotary files; In Group A, the mesial canals were prepared two sizes larger than the Initial Binding File, utilizing 35#/0.04 and 40#/0.04 for the distal canals. In Group B, the mesial canals were enlarged by three sizes compared to the IBF, using 40#/0.04, and the distal canals were prepared with 45#/0.04 files.

Patients were questioned on a modified VAS form to indicate the degree of their pain and assisted in telling their pain intensity during the following periods: 12, 24, and 72 h, and after a week.

The VAS data, analyzed as non-parametric, underwent the signed-rank test for between-group comparisons, Friedman’s test for within-group comparisons, and the Nemenyi post hoc test for further analysis.

The researchers reported the following findings:

• Regardless of measurement time, enlargement of apical preparation was significantly associated with higher pain scores.
• Within both groups, there was a significant reduction of measured pain score with time, with values measured after 12 and 24 h being significantly higher than values measured at other intervals and values measured after three days being significantly higher than the 1-week value.

"The findings showed that the size of the apical preparation significantly influenced postoperative pain outcomes. Differences observed across studies may stem from variations in patient pain perception and methodological approaches," the researchers wrote.

"Future research could investigate and compare postoperative pain among patients with symptomatic and asymptomatic irreversible pulpitis following root canal preparation using E3 Azure rotary instruments," they concluded.

The limitations of this study include the relatively small sample size and the use of IBF to determine apical enlargement size, despite Cone Beam Computed Tomography (CBCT) being recognized as a more reliable method for this purpose.

Reference:

Kataia, M.M., Kataia, E.M., Khalil, H.F. et al. Post-operative pain after root canal preparation with different apical finishing sizes a triple blinded split-mouth clinical trial. BMC Oral Health 24, 800 (2024). https://doi.org/10.1186/s12903-024-04527-9