After revascularisation, a diode laser enhances the effect of internal bleaching
In 42 extracted maxillary incisors, NeoPUTTY and NeoMTA Plus darkened the crown to a similar degree (p = 0.142), and the greatest colour change was produced by hydrogen peroxide bleaching activated with a diode laser and left in place for one week.
Discolouration is the price of revascularisation, but it can be reversed
Revascularisation of an immature tooth saves the tooth, but it often leaves a darker crown, and part of the responsibility lies with the bioceramic materials used to seal the space. Elghazawy's team posed two questions: do two such materials differ in their tendency to stain, and which method of internal bleaching most successfully reverses that discolouration.
Forty-two extracted permanent maxillary incisors were prepared according to a revascularisation model and divided into NeoPUTTY (group I) and NeoMTA Plus (group II). After three months each group was divided into three subgroups according to the bleaching method: diode laser activation, ultrasonic activation, and gel without activation. Colour was measured with a VITA Easyshade V spectrophotometer using the CIELab system before the procedure, three months later, on the day the gel was applied, and after one and two weeks.
Both materials darkened the teeth: after three months all specimens had significantly lower values of lightness and of both chromatic axes (p < 0.001), and the difference between NeoPUTTY and NeoMTA Plus was not significant (p = 0.142). All three bleaching methods raised lightness after one week (p < 0.001), but not equally: in the NeoMTA Plus group, laser activation produced a significantly greater colour change than ultrasound and passive gel (p < 0.001), whereas with NeoPUTTY the same advantage did not reach statistical significance (p = 0.065).
Limitations
This is a laboratory model on extracted teeth, without blood, tissue or saliva; a sample of 42 teeth was distributed across six subgroups, which leaves each of them very small. Follow-up lasted two weeks, so the study says nothing about the stability of the colour achieved.
For your practice
- For a patient with a dark crown after revascularisation, internal bleaching with hydrogen peroxide has support: in this model all three methods of application restored lightness.
- If you have a diode laser in the practice, activation of the gel produced the greatest colour change, and one week of action was sufficient.
- The choice between NeoPUTTY and NeoMTA Plus did not change the tendency to stain; base the decision on handling and cost, and warn the patient in advance about possible discolouration.