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Introduction: This study aimed to evaluate the effect of dentin surface treatment with 37% phosphoric acid or 17% ethylenedia-minetetraacetic acid (EDTA) before Internal Bleaching with 35% hydrogen peroxide using the walking bleach technique. Material and Methods:This experimental in vitro study used 66 human premolars extracted for orthodontic reasons, which were debrided, endodontically prepared, and pigmented with chromogens derived from blood decomposition. The samples were randomly divided into three groups (n=22). Group A: bleaching agent without dentin conditioning; group B: bleaching agent in dentin conditioned with phosphoric acid 37%; group C: bleaching agent in dentin conditioned with 17% EDTA. 4 applications of bleaching agent were used with a separation of 4 days between each session. The initial color (baseline) and after each application was determined by spectrophotometry, recording the CIE L*a*b* values and the total color variation between the initial parameters and the different evaluation times. Results: Data were statistically analyzed with the Wilcoxon test. This showed statistically significant differences for the total variation of the color between the study groups, with the control group in no case inferior to the rest. Conclusion: The application of 37% phosphoric acid increased the effectiveness of the bleaching agent when compared to 17% EDTA. However, these did not increase the effectiveness compared to the application of the bleaching agent without a previous dentin surface treatment., Introducción: El objetivo de este estudio fue evaluar el efecto del tratamiento de superficie dentinaria con ácido fosfórico al 37% o EDTA al 17% previo al blanqueamiento Interno con peróxido de hidrógeno al 35% por medio de la técnica Walking Bleach. Material y Métodos: Para este estudio experimental in vitro, se utilizaron 66 premolares humanos extraídos por indicación ortodóncica, los cuales fueron desbridados, preparados endodónticamente, y pigmentados con cromógenos derivados de la descomposición sanguínea. Las muestras fueron divididas aleatoriamente en 3 grupos (n=22). Grupo A: agente blanqueador sin acondicionamiento dentinario, grupo B: agente blanqueador en dentina acondicionada con ácido fosfórico 37% y grupo C: agente blanqueador en dentina acondicionada con EDTA 17%. Se utilizaron 4 aplicaciones de agente blanqueador con una separación de 4 días entre cada sesión. El color inicial (baseline) y tras cada aplicación fue determinado mediante espectrofotometría, registrando los valores CIE L*a*b* y la variación total de color entre los parámetros iniciales y los diferentes tiempos de evaluación. Resultados: Los datos fueron analizados estadísticamente con la prueba de Wilcoxon, arrojando diferencias estadísticamente significativas para la variación total del color entre los grupos de estudio, siendo en ningún caso el grupo control inferior al resto. Conclusión: La aplicación de ácido fosfórico al 37% aumenta la eficacia del agente blanqueador al compararlo con el EDTA 17%, sin embargo, no aumentan la eficacia respecto a la aplicación del agente blanqueador sin un tratamiento de superficie dentinaria previo.

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The aim of this clinical study was to compare the treatment outcome following root surface conditioning using an EDTA gel preparation in conjunction with surgical therapy with that following conventional flap surgery in periodontal intraosseous defects. 36 patients, each of them contributing one intraosseous defect ≥4 mm in depth participated. Defect sites had a probing pocket depth ≥5 mm and bled on probing following hygienic treatment phase. No furcation involvement or endodontic complications were present. In the EDTA group, 18 consecutive patients, defects were treated by root conditioning with EDTA gel for 3 minutes in combination with surgical therapy. In the control group, 18 patients, conventional flap surgery was performed without root conditioning. Chlorhexidine rinsings 0.2% were prescribed following surgery for 2-3 weeks with modified oral hygiene instruction. A strict recall program was implemented including professional prophylaxis and oral hygiene reinforcement every 4-6 weeks until 6-month re-evaluation. Baseline probing pocket depths and defect depths of 7.1±1.3 mm and 6.9±1.6 mm in the EDTA group and 7.6±1.9 mm and 6.6±1.7 mm, respectively, in the control group were measured. 6-month clinical results showed a significant probing attachment level gain of 1.8±1.5 mm and 1.0±1.7 mm in the EDTA and control groups respectively. A probing bone gain of 1.0±1.3 mm in the EDTA group was measured with a non-significant gain of 0.4±1.2 mm in the control group. Radiographic analysis confirmed these results. There were no statistically significant differences in treatment outcome between the group treated by root conditioning in combination with flap surgery and conventional flap surgery alone.