Evaluation of different internal bleaching methods after application of two bioceramic formulations in revascularization treatment: an in vitro study.

To evaluate the staining potential of two bioceramic formulations, NeoPUTTY and NeoMTA Plus, in a revascularization model and to assess the bleaching efficacy of hydrogen peroxide with and without ultrasonic or diode laser activation at different application time intervals. Forty-two extracted permanent maxillary incisors were prepared for revascularization and randomly allocated to two groups: NeoPUTTY (GI) and NeoMTA Plus (GII). After 3 months, each group was further subdivided into three subgroups using the internal bleaching method: diode laser activation (a), ultrasonic activation (b), and no activation (c). CIELab* values were measured using the VITA Easyshade V spectrophotometer at pre-revascularization (T0), 3 months post-revascularization (T1), on the day of bleaching gel application (T2), and after one week (T3) and two weeks (T4) of bleaching gel application. All specimens showed significant decreases in L*, a*, and b* values at T1 (p < 0.001). Group I exhibited a non-significantly higher ΔE00 value between T0 and T1 than Group II (p = 0.142). All internal bleaching methods produced significant increases in L* and significant decreases in a* and b* at T3 compared with T1 (p < 0.001). GIa demonstrated a non-significantly higher ΔE00 value between T1 and T3 than GIb and GIc (p = 0.065), whereas GIIa exhibited a significantly higher ΔE00 value than GIIb and GIIc (p < 0.001). NeoPUTTY and NeoMTA Plus exhibited comparable staining potential. The bleaching efficacy of hydrogen peroxide was enhanced when the bleaching gel was activated with a diode laser and left in place for one week. A one-week application of a diode-laser-activated hydrogen peroxide bleaching gel may be an effective approach for reversing coronal discoloration following revascularization.