In Vitro analysis of effect of heat used in dental bleaching on human dental enamel

Abstract

From a cosmetic point-of-view, white teeth are important for integration of an individual into society. Thus, dental bleaching may be used to reach this objective. When analyzing several proposed techniques, it was observed that heat is frequently involved either in direct application or as a result of a chemical reaction. Taking into account the importance of preserving dental structures, the present study analyzed possible injuries to enamel when heat is used in the bleaching procedure. A colorimetric method was used and the results showed that there was no difference when heat was used. In only one case did the non-communicating tufts become communicating.

Ex-vivo evaluation of the intrapulpal temperature variation and fracture strength in teeth subjected to different external bleaching protocols

“…This result can be attributed to the fact that the temperature readings in that study were made directly on the thermocouple without using natural teeth, as in the present study, and confirms that dentin is a natural thermal insulating and reduces significantly the amount of heat that reaches the pulp chamber (3).…”

“…emitting diode (LED)-laser system, blue plasma arc lamp, argon laser, GaAlAs diode laser, ultraviolet light, Er:YAG laser and CO 2 laser, are used to catalyze the bleaching process by intensifying the oxi-reduction reaction and accelerating the release of hydroxyl (OH -) radicals (3)(4)(5). The catalyst effect of photoactivation permits the application of the bleaching gel several times in the same bleaching session (4).…”

Nonvital Tooth Bleaching, Noninvasive Technique: A Case Report

“…6 However, occasionally darkening after internal bleaching can be observed which is presumably caused by diffusion of staining substances and penetration of bacteria through marginal gaps between the filling and the tooth. 7 Some modifications have been done in an attempt to minimize the risk of cervical or apical resorption; thus, a base of 1 -2 mm glass ionomer cement was placed over filling material of the root to have a mechanical barrier between the sealed root canal and the bleaching gel, which is in agreement with other studies Friedman et al as they did not use an intermediate lining prior to the bleaching material. 8 Another modification added to the bleaching technique was that on reaching the desired shade guide; thus, the pulp chamber was filled by calcium hydroxide for seven days before the final filling material.…”

Effect of different restorative procedures on the fracture resistance of teeth submitted to internal bleaching

“…According to Kawamoto and Tsujimoto, 23 the OH radical resulting from hydrogen peroxide degradation is responsible for tooth whitening, and acts on intertubular and peritubular dentin, destroying its organic portion, increasing permeability, 24,25 and decreasing its hardness and elasticity modulus, 2,3 which can be intensified with a greater exposure time of the tooth to the bleaching agent. This may explain the greater susceptibility to fracture observed in the teeth endodontically treated, bleached and only sealed with Coltosol (GIII).…”