Pulp chamber temperature changes and enamel surface analysis during orthodontic composite removal using 3 different burs in a repeatable approach: an experimental study.

Background: During the debonding phase every clinician has to take care of preserving the enamel structure and tooth temperature. The objective of this study was to analyze in vitro the increase of the pulp chamber temperature and the wearing of enamel surface, during adhesive removal after debonding.

Methods: Sixty extracted human teeth were selected. An orthodontic bracket was bonded on each tooth and after bracket removal, intraoral scanner pictures were used to evaluate ARI for each tooth. Three different burs were tested: tungsten-carbide multiple blades, arkansas stone and ceramic bur. A mechanical arm controlled by a dedicated software was used to reproduce a repeatable act of composite removal. To analyze in vitro the pulp chamber temperature during the composite removal procedure, teeth were treated endodontically placing a thermocouple through the root canal from the apex. A software registered temperature changes in a continuous manner. The enamel surface of every tooth was tested after the removal of composite with an optical stereoscopic microscope.

Results: An association existed between maximum internal pulp chamber temperature variation and irrigation (P<0.0001) and between maximum internal pulp chamber temperature variation and bur type (P=0.0133), with a significantly lower temperature increase produced by the arkansas bur. A significant difference among groups was detected for ESI and EDI assessment (P=0.002, P=0.010).

Conclusions: Considering the initial setup, temperature variation analysis showed more conservative results using the arkansas burs with irrigation. ESI and EDI indexes showed significant enamel surface damage using tungsten-carbide burs.