Investigating a calcium silicate-based cement as a dentine replacement material in permanent mandibular molars treated with full pulpotomy: A laboratory study of fracture strength and microleakage.

OBJECTIVES

To evaluate a calcium silicate-based cement (Biodentine) as a bulk restorative material in pulpotomized molar teeth in terms of fracture strength and microleakage.

METHODS

Ninety permanent mandibular molars were included (n = 60 fracture testing; n = 30 microleakage) and randomly allocated into five groups: intact teeth (positive control); unrestored MOD cavity and pulpotomy (negative control); MOD cavity and pulpotomy restored with 6-mm bulk Biodentine + 2-mm nanohybrid composite; MOD cavity and pulpotomy restored with 3-mm Biodentine + incremental composite; and MOD cavity and pulpotomy restored with 3-mm Biodentine + bulk-fill composite. Specimens were thermocycled (5000 cycles, 5-55 °C, 30 s dwell time) and subjected to static compressive loading at 30° (crosshead speed of 0.5 mm/min) in a universal testing machine. Fracture load and pattern were recorded. Microleakage was evaluated using dye penetration. Data were analyzed using Kruskal-Wallis, Dunn's post hoc, and Fisher's exact tests.

RESULTS

Intact teeth demonstrated the highest fracture strength (1761 ± 152 N), while unrestored teeth showed the lowest values (578 ± 99 N) (p < 0.001). Biodentine-based restorations significantly increased fracture strength compared with the negative control group (p < 0.001). Only teeth restored with 6 mm bulk Biodentine and a 2-mm nanohybrid composite layer exhibited fracture strength comparable to intact teeth (1282 ± 133 N; p = 0.15). Subcrestal fractures initiating at proximal line angles were the most frequently observed fracture pattern. Microleakage was limited to partial dye penetration along the proximal gingival margin, without penetration into the Biodentine-dentine interface.

CONCLUSION

Bulk placement of Biodentine enhanced the fracture strength of pulpotomized molar teeth, supporting its clinical application as a dentine replacement material.

CLINICAL SIGNIFICANCE: Biodentine can be used in a bulk of 6 mm following full pulpotomy in molars to improve the fracture resistance.