Can different agents reduce the damage caused by bleaching gel to pulp tissue? A systematic review of basic research.

Objectives: This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells. Materials and Methods: Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed. Results: Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies. Conclusions: Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings. Trial Registration: PROSPERO Identifier: CRD42022337192.

Conservative approach to masking a darkened tooth with a direct composite resin restoration: a case report with 5-year follow-up.

The objective of this case report is to describe a direct conservative technique for restoring the esthetics and function of a severely discolored endodontically treated tooth. A 25-year-old man presented with an esthetic complaint about severe darkening of his endodontically treated maxillary left central incisor. The tooth had adequate sound tooth structure, so the placement of a conservative direct composite resin veneer was proposed. The preparation included minimal removal of tooth structure, and a photoactivating opacifier was placed to mask the darkened substrate prior to restoration with composite resin. The restorative composite resin was placed with an incremental layering technique, restoring form, function, and esthetics. A routine follow-up examination 5 years after placement of the veneer revealed that it still provided satisfactory function and esthetics despite slight incisal wear and loss of brightness. The placement of direct composite resin veneers in association with opacifying pigments is a simple, low-cost alternative for providing immediate esthetic restoration of teeth with severe color change without extensive removal of tooth structure.