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

NCT06991842 | Recruiting

• 2 other identifiers: ETCH-PRO2025-00584
• Study Type: interventional
• Target: 66
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to learn if reducing the phosphoric acid etching (PAE) time affects the performance of direct resin-based composite (RBC) restorations in permanent anterior teeth. It will also learn about the safety of using a shortened PAE protocol. The main questions it aims to answer are: Does a shorter PAE time lead to more or less marginal staining in restored teeth? What sensitivity or other clinical issues do participants experience after restoration using different PAE times? Researchers will compare a reduced PAE protocol to a standard PAE protocol to see how each affects the outcome of Class III and IV anterior restorations. Participants will: Receive one or two direct RBC restorations using either a shortened or standard PAE protocol Visit the clinic for follow-ups at baseline, and at 1, 2, 3, and 5 years after restoration Have sensitivity and restoration quality evaluated using clinical exams, photographs, and questionnaires

Conditions

Dental Restoration, Permanent; Dental Caries (Disorder); Dental Restoration Failure

Keywords

Resin-based composite; Universal adhesive; Class III restoration; Class IV restoration; Phosphoric acid etching; Adhesive dentistry; Anterior tooth restoration; Permanent dental restoration; Dental bonding; Etch-and-rinse technique; Restorative dentistry

Outcome Measures

Primary Outcomes (1)

• Frequency of Marginal Staining in Direct Resin-Based Composite Restorations of Anterior Teeth

  The primary outcome measure is the frequency of marginal staining in direct resin-based composite restorations placed in anterior permanent teeth, assessed at baseline and at 1, 2, 3, and 5 years post-restoration. Marginal staining will be evaluated using the Category A2 guideline from the FDI criteria. This outcome aims to determine if the duration of phosphoric acid etching affects the incidence of marginal staining over time.

  Baseline, 1, 2, 3, and 5 years post-restoration placement

Secondary Outcomes (11)

• Postoperative Sensitivity/Pulpal Status

  7-10 days post-restoration placement

• Fracture of material/retention

  Baseline, 1, 2, 3, and 5 years post-restoration placement

• Marginal adaptation

  Baseline, 1, 2, 3, and 5 years post-restoration placement

• Proximal contact point

  Baseline, 1, 2, 3, and 5 years post-restoration placement

• Form/contour

  Baseline, 1, 2, 3, and 5 years post-restoration placement

Study Arms (2)

Standard PAE Protocol Group

ACTIVE COMPARATOR

In this arm, participants will receive a Class III or Class IV resin-based composite (RBC) restoration with a standard etch-and-rinse bonding protocol. Phosphoric acid etching (PAE) will be applied to both enamel and dentin for 15-30 seconds and 10-15 seconds, respectively. After etching, a universal adhesive will be applied, followed by the placement of the RBC using a standard layering technique with separately photo-polymerized increments. The final restoration will be polished to ensure proper contour and surface finish.

Procedure: Permanent dental restoration

Reduced PAE Duration Protocol Group

EXPERIMENTAL

Participants in this arm will receive Class III or Class IV RBC restorations using a reduced PAE duration protocol. Phosphoric acid etching will be applied simultaneously to both enamel and dentin for a brief 10-second period, followed by the application of the universal adhesive and placement of the RBC. Similar to the standard protocol group, the restoration will be placed using a layering technique with photo-polymerized increments and polished to completion. This group aims to evaluate the effect of a reduced etching time on restorative outcomes compared to the standard PAE protocol.

Procedure: Permanent dental restoration

Interventions

Permanent dental restoration PROCEDURE

In both study arms, permanent dental restorations are made with resin-based composite in permanent anterior teeth. Both study arms will use identical materials for the resin-based composite restoration (Tetric Plus Flow and Tetric Plus Fill) and universal adhesive (Adhese Universal), with the only difference being the duration of the phosphoric acid etching step. All other aspects of the restorative procedure, such as isolation of the operative field, application techniques, and final polishing, will remain consistent across both arms.

Reduced PAE Duration Protocol Group; Standard PAE Protocol Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Signed informed consent by the participant
• Age 18 years or older
• Indication for a Class III or Class IV resin-based composite (RBC) restoration on an anterior permanent tooth due to one or more of the following conditions:
• Proximal carious lesion with cavitation
• Defective restoration requiring replacement
• Necessary proximal reshaping due to developmental anomalies (e.g., peg teeth, proximal gaps from Bolton discrepancies, orthodontic tooth position, or esthetic concerns like black triangles caused by periodontal tissue recession)
• Vital teeth with regular sensitivity
• Sufficient language skills to understand and comply with study procedures
• Preoperative Visual Analog Scale (VAS) scores \< 3 for tooth sensitivity and biting discomfort
• Good oral hygiene, including the ability to maintain effective oral hygiene
• Clinical periodontal health (intact periodontium or a reduced periodontium due to non-periodontal causes or after periodontal treatment)

You may not qualify if:

• Inability to achieve sufficient isolation and contamination control during restorative procedures
• Class IV restoration required due to crown fracture, crown-root fracture, extensive tooth wear, or carious lesion affecting the incisal edge
• Missing antagonist tooth without prosthodontic replacement
• Intent to undergo professional tooth bleaching within five years following the Class III or IV restoration (Note: Professional tooth bleaching must be completed at least two weeks prior to study enrollment)
• Known or suspected allergy to any constituents of the materials used (e.g., methacrylates or local anesthetics)
• Pregnancy or lactation
• Acute or chronic health conditions that may impair study participation (e.g., systemic diseases, oral conditions, or treatments that interfere with study procedures)

Sponsors & Collaborators

• Florin Eggmann: lead

Study Sites (1)

University Center for Dental Medicine Basel UZB

Basel, Canton of Basel-City, 4058, Switzerland

RECRUITING

Related Publications (4)

• Wong J, Tsujimoto A, Fischer NG, Baruth AG, Barkmeier WW, Johnson EA, Samuel SM, Takamizawa T, Latta MA, Miyazaki M. Enamel Etching for Universal Adhesives: Examination of Enamel Etching Protocols for Optimization of Bonding Effectiveness. Oper Dent. 2020 Jan/Feb;45(1):80-91. doi: 10.2341/18-275-L. Epub 2019 Jun 21.

  PMID: 31226005 BACKGROUND

• Tsujimoto A, Fischer N, Barkmeier W, Baruth A, Takamizawa T, Latta M, Miyazaki M. Effect of Reduced Phosphoric Acid Pre-etching Times on Enamel Surface Characteristics and Shear Fatigue Strength Using Universal Adhesives. J Adhes Dent. 2017;19(3):267-275. doi: 10.3290/j.jad.a38437.

  PMID: 28597008 BACKGROUND

• Burrer P, Dang H, Par M, Attin T, Taubock TT. Effect of Over-Etching and Prolonged Application Time of a Universal Adhesive on Dentin Bond Strength. Polymers (Basel). 2020 Dec 3;12(12):2902. doi: 10.3390/polym12122902.

  PMID: 33287394 BACKGROUND

• Amran T, Meier D, Amato J, Connert T, Blatz MB, Weiger R, Eggmann F. Accuracy of Selective Enamel Etching: A Computer-assisted Imaging Analysis. Oper Dent. 2023 Sep 1;48(5):538-545. doi: 10.2341/22-114-L.

  PMID: 37635464 BACKGROUND

MeSH Terms

Conditions

Dental Caries

Interventions

Dental Restoration, Permanent

Condition Hierarchy (Ancestors)

Tooth Demineralization; Tooth Diseases; Stomatognathic Diseases

Intervention Hierarchy (Ancestors)

Dental Prosthesis; Prosthodontics; Dentistry; Prostheses and Implants; Equipment and Supplies

Study Officials

• Florin Eggmann, PD Dr. med. dent.

  University of Basel

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Florin Eggmann, PD Dr. med. dent.

CONTACT

+41 61 267 26 80; florin.eggmann@unibas.ch

Roland Weiger, Prof. Dr. med. dent.

CONTACT

+41 61 267 26 25; roland.weiger@unibas.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Sponsor-Investigator, Head of Cariology

Model Details: This is a single-center, two-arm, parallel-group, randomized controlled trial comparing the clinical outcomes of direct resin-based composite restorations in anterior permanent teeth using either a standard phosphoric acid etching (PAE) protocol or a reduced PAE duration protocol. Each participant is allocated to one of the two groups and receives a single intervention type throughout the study period. No crossover is performed, and all restorative procedures follow standardized protocols, differing only in the PAE regimen.

Study Record Dates

• First Submitted: May 7, 2025
• First Posted: May 28, 2025
• Study Start: June 1, 2025
• Primary Completion (Estimated): May 31, 2031
• Study Completion (Estimated): December 31, 2031
• Last Updated: August 5, 2025

Record last verified: 2025-08

Locations

CH (1)