In vitro assessment of intracoronal bleaching using 2% chlorhexidine gel associated to different bleaching agents / Estudo "in vitro" da associação da clorexidina gel 2% a agentes clareadores utilizados durante o clareamento dental interno

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Non-vital tooth bleaching is a conservative esthetic treatment for endodontically treated discolored teeth. It is effective and relatively inexpensive. The purpose of this study was to evaluate ?in vitro? the association of sodium perborate + 2% chlorhexidine gel comparing with sodium perborate + distilled water; sodium perborate + 30%hydrogen peroxide (H2O2) and 37% carbamide peroxide with and without chlorhexidine used as bleaching agents evaluating: bleaching efficacy; capacity to prevent coronal microleakage; antimicrobial activity. For the bleaching efficacy study 220 bovine incisors were artificially stained using whole blood. The samples were divided into 11 groups and the intracoronal bleaching was performed using the ?walking bleach technique?. The bleaching agents were replaced three times at 7 day intervals. Using digital photos and a shade guide created for bovine teeth, the samples were evaluated at day 0, 7, 14, 21 and 28. On evaluation day, the photos were examined by 3 endodontists giving scores from 1 to 5 based on the shade guide created. For the microleakage study it was used 110 bovine incisors with endodontic access. The pulp chamber was filled with bleaching agents and sealed with temporary sealer. The teeth were immersed in saliva and the time to contaminate the root canal was annotated. For the antimicrobial activity study two different methodologies were used. Both of them evaluated the antimicrobial efficacy against three microorganisms: Enterococcus faecalis, Streptococcus mutans e Candida albicans. The zone inhibition test was performed putting the bleaching agent into stainless tubes and measuring the inhibition zone on the agar plate where the microorganisms were cultured. The contact direct test evaluated the time needed to bleaching agents to kill a microorganism. The results showed that after 28 days of bleaching, all agents exhibited similar bleaching scores. The groups that had chlorhexidine added, the time required to contaminate the root canal was increased between 8 and 16 days. The antimicrobial activity of the bleaching agents showed that the most resistant microorganism in both methodologies was E. faecalis and when 2% chlorhexidine gel was added to the bleaching agents the antimicrobial activity was increased. In conclusion, as 2% chlorhexidine did not reduce the bleaching efficacy, increased the time required to a possible contamination of the root canal and increased the antimicrobial activity of bleaching agents. The association of 2% chlorhexidine to the bleaching agents tested is recommended

ASSUNTO(S)

dentistry bleaching endodontics odontologia tooth dentes - clareamento endodontia

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