Effect of Phosphoric Acid Etching Duration on Direct Resin-Based Composite Restorations in Permanent Anterior Teeth

This clinical trial, "Effect of Phosphoric Acid Etching Duration on the Performance of Direct Resin-Based Composite Restorations in Permanent Anterior Teeth: A Randomized Controlled Single-Center Trial," or ETCH-PRO for short, aims to investigate whether reducing the duration of phosphoric acid etching (PAE) impacts the effectiveness and safety of direct resin-based composite (RBC) restorations in permanent anterior teeth.

Specifically, it seeks to answer:

DOES A SHORTER PAE TIME AFFECT MARGINAL STAINING IN RESTORED TEETH?

WHAT POSTOPERATIVE SENSITIVITY OR OTHER CLINICAL ISSUES DO PARTICIPANTS EXPERIENCE WITH DIFFERENT PAE TIMES?

Researchers at the University Center for Dental Medicine Basel UZB will compare a reduced PAE protocol to a standard PAE protocol. Participants will receive one or two direct RBC restorations using either protocol and attend follow-up visits at baseline (7-10 days post-op), and at 1, 2, 3, and 5 years after restoration. During these visits, sensitivity and restoration quality will be assessed through clinical exams, photographs, and questionnaires.

DETAILED DESCRIPTION

BACKGROUND AND RATIONALE

Phosphoric acid etching (PAE) is crucial for enhancing enamel bond strength in restorative dentistry. When using etch-and-rinse adhesives, PAE is necessary for successful dentin bonding. However, with self-etch adhesives, PAE of dentin is not recommended due to potential negative effects on adhesion.

The increasing use of universal adhesives offers clinicians flexibility in choosing between etch-and-rinse and selective enamel etching techniques. A key challenge with selective enamel etching is the risk of inadvertently etching the dentin, which can compromise adhesion and the longevity of the restoration.

Recent laboratory studies suggest that shortening PAE duration does not negatively affect bond strength, potentially mitigating the risks associated with accidental dentin etching. However, clinical data on the long-term outcomes of direct RBC restorations in anterior teeth using reduced PAE times is limited.

This study aims to address this gap by evaluating the clinical performance of RBC restorations in anterior permanent teeth using a reduced PAE protocol compared to a standard protocol.

The study specifically includes teeth requiring Class III or Class IV restorations due to:

Proximal carious lesions with cavitation

Replacement of defective restorations

Necessary proximal reshaping (e.g., for developmental anomalies, proximal gaps, or esthetic concerns like black triangles)

Class IV cases are strictly limited to non-fracture-related reshaping.

The study operates under the null hypothesis, stating there is no significant difference in clinical outcomes between the two PAE protocols. Confirmation of this could support adopting reduced PAE durations in routine practice, potentially improving procedural efficiency and minimizing iatrogenic effects.

RISK/BENEFIT ASSESSMENT

STUDY OVERVIEW

All procedures adhere to established, evidence-based restorative practices, using CE-marked materials and standardized protocols to ensure patient safety and consistency. This study is classified as Risk Category A according to ClinO, Art. 61, indicating minimal risks and burdens.

ANTICIPATED CLINICAL BENEFITS

While participants may not experience immediate personal benefits, their involvement will contribute valuable data to improve clinical protocols and outcomes for future patients.

RESIDUAL RISKS AND ADVERSE DEVICE EFFECTS (ADES)

The materials used comply with CE marking requirements, presenting minimal residual risks. Minor postoperative discomfort or sensitivity may occur but are considered rare and manageable.

RISKS DUE TO CONCOMITANT TREATMENTS

No specific risks from concomitant treatments are anticipated. Each participant's medical history will be reviewed during screening to monitor potential interactions.

PARTICIPATION RISKS AND SAFETY MEASURES

Participants are fully informed about the study's procedures, potential risks, and the lack of direct benefits. Written informed consent is obtained before participation. Close monitoring will ensure adverse events are promptly addressed.

RISK-MITIGATION STRATEGIES

Comprehensive risk analysis and procedural safeguards

Proper training and calibration of all clinical personnel

Clear patient communication and continuous monitoring

Standardized procedures to minimize discomfort and risks

RISK-BENEFIT ASSESSMENT

The minimal and manageable risks are outweighed by the potential benefits of improving long-term restorative outcomes and informing future best practices.

OBJECTIVES

PRIMARY OBJECTIVE

To compare the frequency of marginal staining in anterior direct RBC restorations between the standard and reduced PAE protocol groups.

SECONDARY OBJECTIVES

To assess the frequency of postoperative hypersensitivity levels following restoration

• Postoperative Sensitivity/Pulpal Status [Срок оценки: 7-10 days post-restoration placement]
• Fracture of material/retention [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Marginal adaptation [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Proximal contact point [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Form/contour [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Occlusion/wear [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Caries at restoration margins [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Dental hard tissue defects at the restoration margin [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Surface luster/surface texture [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Color match [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]
• Patient's view [Срок оценки: Baseline, 1, 2, 3, and 5 years post-restoration placement]