RESUMO
OBJECTIVE: To evaluate the effect of Er,Cr:YSGG laser associated or not with acidulated phosphate fluoride (APF) on the control of enamel erosion progression. DESIGN: Enamel slabs (4 mm × 4 mm × 2 mm) from bovine incisors were flattened, polished, and received a tape on their test surfaces, leaving a 4 mm × 1 mm area exposed. Specimens were eroded (10 min in 1% citric acid solution) and randomly assigned into 8 experimental groups (n = 10): Control (no treatment); F (APF gel, 1.23% F, pH 3.6-3.9); Er,Cr:YSGG laser irradiation (P1: 0.25 W, 20 Hz, 2.8 J/cm2, 56 W/cm2); Er,Cr:YSGG laser irradiation (P2: 0.50 W, 20 Hz, 5.7 J/cm2, 1136 W/cm2); Er,Cr:YSGG laser irradiation (P3: 0.75 W, 20 Hz, 8.5 J/cm2, 1704 W/cm2); F + Laser P1; F + Laser P2; F + Laser P3. Specimens were then subjected to erosive cycling (5 min immersion in 0.3% citric acid solution, followed by immersion in artificial saliva for 60 min; 4×/day for 5 days). At the end of cycling, surface loss (SL, in µm) was determined with optical profilometry. Selected specimens were further evaluated by environmental scanning electron microscopy (n = 3). Data were analyzed using Kruskal-Wallis and Tukey tests (α = 0.05). RESULTS: Group F + Laser P2 had the lowest SL value, differing significantly from the control; however, with no significant difference from the other groups. All groups, except F + Laser P2, showed no significant difference in SL when compared with the control. An irregular and rough surface, suggestive of a melting action of laser, was observed on enamel in Laser P2 and F + Laser P2 groups. CONCLUSIONS: Association of the Er,Cr:YSGG laser in parameter 2 with fluoride was the only treatment capable of controlling the progression of enamel erosion.
Assuntos
Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/efeitos da radiação , Fluoretos/uso terapêutico , Lasers de Estado Sólido/uso terapêutico , Erosão Dentária/radioterapia , Erosão Dentária/terapia , Animais , Bovinos , Ácido Cítrico/efeitos adversos , Esmalte Dentário/patologia , Progressão da Doença , Incisivo , Microscopia Eletrônica de Varredura , Saliva Artificial , Propriedades de Superfície , Erosão Dentária/patologia , Erosão Dentária/prevenção & controle , Remineralização DentáriaRESUMO
Nd:YAG laser and its association with fluoride have been proposed as an option for the prevention of dental erosion. This study evaluated the progression of existing dentin erosive lesions after treatment with different Nd:YAG laser (1064 nm) protocols, associated or not with fluoride. Erosive lesions were created with 1 % citric acid for 10 min in human dentin specimens. They were randomly assigned into eight groups (n = 15): no treatment (control), 1-min application of 2 % sodium fluoride gel (NaF), Nd:YAG1 (Nd:YAG laser irradiation 0.5 W; 50 mJ; ~41.66 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG2 (0.7 W; 70 mJ; ~62.50 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG3 (1 W; 100 mJ; ~54,16 J/cm(2); 10 Hz; 40 s; 1 mm unfocused), NaF + Nd:YAG1, NaF + Nd:YAG2, and NaF + Nd:YAG3. After treatment, the specimens were submitted to a 5-day erosion-remineralization cycling model, 6×/day. Dentin surface loss (SL) was evaluated with optical profilometry after the formation of the initial lesion; after treatment; and after days 1, 3, and 5. Data were statistically analyzed (alpha = 0.05). Significant differences were observed among the groups in all testing times (p < 0.001), except after initial lesion formation. Loss of dentin surface was observed after irradiation with all Nd:YAG laser protocols (p < 0.05). The association fluoride and laser did not differ significantly from laser alone. NaF showed the lowest values of SL and Nd:YAG2 and NaF + Nd:YAG2, the highest. Within the limitations of an in vitro study, it was concluded that laser irradiation, according to the parameters used, was not an appropriated approach to prevent dentin erosion progression, even when it was associated with fluoride.
Assuntos
Dentina/efeitos dos fármacos , Dentina/efeitos da radiação , Lasers de Estado Sólido/uso terapêutico , Fluoreto de Sódio/farmacologia , Erosão Dentária/tratamento farmacológico , Erosão Dentária/radioterapia , Humanos , Dente Molar/efeitos dos fármacos , Dente Molar/efeitos da radiação , Fluoreto de Sódio/uso terapêutico , Erosão Dentária/prevenção & controleRESUMO
This study evaluated the combined effect of fluoride compounds and CO(2) laser in controlling the permeability of eroded enamel. Bovine enamel slabs (3 × 2 mm) were cycled twice through an alternating erosion and remineralization regimen. Slabs were immersed in 20 ml of orange juice (pH 3.84) for 5 min under agitation, rinsed with deionized water, and stored in artificial saliva for 4 h to form erosive lesions. Specimens were then divided into four groups (n = 10), which were treated for 1 min with either a control or with one of the following gels: amine fluoride (AmF), titanium tetrafluoride (TiF(4)), or sodium fluoride (NaF). Half of the specimens were irradiated with a CO(2) laser (λ = 10.6 µm; 2.0 W). Specimens were cycled two more times through the aforementioned erosion-remineralization regimen and were subjected to permeability assessment. ANOVA demonstrated a significant interaction between fluoride and laser treatment (p = 0.0152). Tukey's test showed that when fluoride was applied alone, TiF(4) resulted in lower enamel permeability than that observed after application of the placebo gel. Intermediate permeability values were noted after NaF and AmF had been used. A significant reduction in enamel permeability was obtained when fluoride was combined with CO(2) laser treatment, with no difference between fluoride gels. Permeability of eroded enamel may be reduced by combining the application of fluoride gels with CO(2) laser irradiation.