A Method to Bond Vital Dentin With a Microleakage-Free Hybrid Layer

Area of Science:

• Dentistry
• Dental Materials Science
• Restorative Dentistry

Background:

• Dental restorations aim to seal tooth structure, preventing microleakage and secondary caries.
• Traditional bonding techniques often require multiple steps and careful moisture control.
• Primerless wet bonding techniques offer potential simplification and improved clinical efficiency.

Purpose of the Study:

• To evaluate dye penetration at Class V tooth-restoration margins using a primerless wet bonding technique.
• To compare MMA-TBB bonding resin with and without the 4-META monomer promoter.
• To assess the formation of a hybrid layer under both in-vitro and in-vivo conditions.

Main Methods:

• Class V cavities were prepared on extracted human teeth (in-vitro) and vital teeth (in-vivo).
• Teeth were conditioned with a citric acid/ferric chloride solution for varying durations.
• Bonding was performed with either 4-META/MMA-TBB or MMA-TBB resin, followed by composite restoration.
• Restored vital teeth were subjected to intraoral function for seven days before analysis.
• Dye penetration was measured microscopically, and hybrid layer formation was assessed via SEM.

Main Results:

• No hypersensitivity or pain was reported in vital teeth during the in-vivo phase.
• No dye penetration was detected at any margins for in-vitro restorations.
• Minimal dye penetration (0.13 mm) was observed in only one intraoral restoration at the cementum/dentin margin.
• Leakage-free specimens consistently showed a well-formed hybrid layer after chemical modification.

Conclusions:

• The primerless wet technique with MMA-TBB or 4-META/MMA-TBB effectively creates a microleakage-free hybrid layer.
• The demineralized substrate achieved with the 1-1 conditioner provides sufficient permeability for effective bonding.
• Microleakage-free intraoral restorations are crucial for enhancing the longevity of restored teeth.