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

Abstract

The aim of this study was to evaluate the influence of different restorative procedures on the fracture resistance of endodontically treated teeth submitted to intracoronal bleaching. Fifty upper central incisors were distributed into 5 groups: GI -healthy teeth; GII -endodontically treated teeth sealed with Coltosol; GIII -endodontically treated teeth bleached and sealed with Coltosol; GIV -endodontically treated teeth bleached and restored with composite resin; and GV -endodontically treated teeth bleached and restored with a fiberglass post and composite resin. In the bleached specimens, a cervical seal was made prior to bleaching with 38% hydrogen peroxide. The gel was applied on the buccal surface and in the pulp chamber, and was then light-activated for 45 s. This procedure was repeated three times per session for four sessions, and each group was submitted to the restorative procedures described above. The specimens were submitted to fracture resistance testing in a universal testing machine. There were statistically significant differences among the groups (p < 0.05). The mean value found for GIII was the lowest (0.32 kN) and was significantly different from the values found for GI (0.75 kN), GII (0.67 kN), GIV (0.70 kN), and GV (0.72 kN), which were not significantly different from each other (p > 0.05). The restorative procedures using composite resin were found to successfully restore the fracture resistance of endodontically treated and bleached teeth.

Effects of the Ratio between Pigment and Bleaching Gel on the Fracture Resistance and Dentin Microhardness of endodontically treated Teeth

“…The fracture resistance reduction occurred due to the higher HP catalysis; so, it is also possible that a higher release and concentration of oxidative radicals have occurred, which negatively affected the physical properties of the composite resin in accordance with Bandeca et al 15 The HP at high concentrations causes deleterious effects on the organic and inorganic components of the dental structure. [16][17][18][19][20][21] In contrast, the addition of greater amount of pigment in the total volume of the bleaching 27.9 33.6 41.0 27.5 No significant differences were found among the bleaching protocols (p > 0.05). G1 (HP3), 35% HP using pigment (3:1 ratio); G2 (HP1), 35% HP using pigment (1:1 ratio); G3 (positive control), 38% HP; G4 (negative control), unbleached gel increases the chemical catalysis, due to the increase in local temperature.…”

Fracture resistance of endodontically-treated teeth submitted to bleaching treatment with hydrogen peroxide and titanium dioxide nanoparticles photoactivated by LED-laser

“…Peroxides show an oxidizing action, which modifies the structure and mechanical properties of the tooth tissues 6 , providing the degradation of collagen fiber and hyaluronic acid 18 . These changes cause dentin microhardness reduction and consequently reduction of crown resistance to fracture [19][20][21][22] .…”

Bonding Effectiveness of Universal Adhesive to Intracoronal Bleached Dentin Treated with Sodium Ascorbate

“…Os dados (MPa) foram analisados pela ANOVA e teste de Tukey (α=0,05). Os menores valores de resistência ao cisalhamento foram encontrados para os espécimes clareados (8,54 MPa) comparados com aqueles não clareados (12,13 MPa) (p<0,05). A resistência de união dos grupos tratados com ascorbato de sódio foi maior que aqueles não tratados (p<0,05), independentemente da estratégia empregada.…”

“…A resistência de união dos grupos tratados com ascorbato de sódio foi maior que aqueles não tratados (p<0,05), independentemente da estratégia empregada. Grupos restaurados sem ascorbato de sódio demonstraram menores valores de resistência de união para ambas as estratégias adesivas ER (8,32 MPa) e SE (8,28 MPa) (p<0,05). O grupo tratado com ascorbato de sódio a 10% submetido à estratégia ER (10,14 MPa) foi similar ao não tratado (p>0,05).…”

“…However, waiting to perform definitive restoration in non-vital bleached teeth is a critical condition, since these teeth present considerable structural loss and the additional bleaching procedure promotes changes in dentin organic content (7) turning them more susceptible to fracture (8). Moreover, endodontically treated teeth, submitted to bleaching and sealed with provisional restoration present higher fracture rates, but they return to normal after definitive restoration with composite resin (8).…”