Repair Versus Replacement of Failed Restorations in Primary Teeth

Repair Versus Replacement of Failed Restorations in Primary Teeth: Protocol for a Non-Inferiority Randomized Clinical Trial

Dental caries affect approximately 573 million children globally, and the management of failed restorations is a frequent clinical issue in pediatric dentistry. Although complete replacement of restorations is traditionally the most commonly adopted approach, repair represents a minimally invasive alternative that preserves healthy dental structure and reduces the risk of pulpal complications. Studies in permanent teeth demonstrate that repair may present longevity similar to replacement; however, there is no robust evidence regarding this comparison in primary teeth. This randomized controlled clinical trial, with parallel groups and a 1:1 allocation ratio, aims to evaluate the non-inferiority of repair compared with replacement of failed restorations in primary molars, using encapsulated high-viscosity glass ionomer cement. Children aged 4 to 8 years with at least one failed restoration eligible for repair in primary molars will be included. Randomization will be stratified by number of surfaces. Teeth (n=824) will be randomly allocated to one of the groups: repair or replacement. The primary outcome will be restoration survival at 24 months. Cost-effectiveness will be evaluated as a secondary outcome. Statistical analysis will use Kaplan-Meier curves and Cox regression with shared frailty (¿=5%).

Study Overview

• Status: Not yet recruiting
• Conditions: Dental Caries; Primary Teeth; Restoration Defects
• Intervention / Treatment: Procedure: Repair of Failed Restoration; Procedure: Replacement of Failed Restoration

• Study Type: Interventional
• Enrollment (Estimated): 382
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tamara K Tedesco, PhD; Phone Number: +5511954866622; Email: tamarakt@usp.br

Study Locations

• Brazil
  • São Paulo
    • São Paulo, São Paulo, Brazil, 05508-000
      • University of São Paulo, School of Dentistry
      • Contact: Tamara K Tedesco, PhD; Phone Number: +5511954866622; Email: tamarakt@usp.br
      • Contact: Camila C Cabral, PhD; Phone Number: +5511996254588; Email: camila.cabral@usp.br
      • Sub-Investigator: Aline S Gusmão, DDS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Children aged 4 to 8 years;
• Presence of at least one defective restoration in a primary molar, involving no more than 3 surfaces;
• Absence of clinical and radiographic signs of pulp involvement;

Exclusion Criteria:

• Tooth without pulp vitality or requiring endodontic treatment;
• Loose or mobile restoration;
• Presence of fistula, abscess, or history of pain;
• Tooth mobility incompatible with the physiological exfoliation timeline;
• Parents/guardians who do not consent to participation by signing the ICF, or children who do not assent to participate in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Repair; Repair of Failed restoration in primary teeth.	Procedure: Repair of Failed Restoration; Prior to the procedure, when needed, local anesthesia with 2% lidocaine and 1:100,000 epinephrine will be used, with relative isolation (cotton rolls and saliva ejector). The defective area will be clinically identified. When present, carious tissue will be selectively removed with hand instruments (dentin curettes) suited to the cavity, preserving as much of the intact original restoration as possible. If no hand instrument fits, the cavity will be enlarged with a small spherical diamond bur at high speed under cooling. The surface will be conditioned with 20% polyacrylic acid (GC Cavity Conditioner) for 10 s, rinsed abundantly, and dried with cotton pellets. For proximal surfaces, a metal matrix and wedge will be placed before the GIC. The capsule will be activated, mixed for 10 s, inserted with an applicator, and adapted by digital pressure with petroleum jelly. Occlusion will be checked with articulating paper and adjusted; surface protection applied with petroleum jelly.
Active Comparator: Replacement; Replacement of Failed Restoration in primary teeth.	Procedure: Replacement of Failed Restoration; Prior to the procedure, when needed, infiltrative local anesthesia with 2% lidocaine and 1:100,000 epinephrine will be administered. Relative isolation will be used, with cotton rolls and a saliva ejector. Complete removal of the defective restorative material will be performed with spherical diamond burs at high speed under cooling, complemented by round burs at low speed to remove remaining restorative material. Selective removal of carious tissue, when present, will be carried out with hand instruments (dentin curettes) suited to the cavity, preserving soft or leathery dentin according to the depth of the lesion. The new restoration will then be placed following the same protocol described for the repair group: conditioning with 20% polyacrylic acid (GC Cavity Conditioner) for 10 s, rinsing and removal of excess water; placement of a metal matrix and wedge, when needed; insertion of the GIC into the cavity; adaptation by digital pressure with petroleum jelly; occlusal adjustment; a

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Restoration survival	Restoration survival will be assessed based on clinical evaluation of the restorations at 6, 12, 18, and 24 months. A restoration will be considered to have survived when it remains clinically satisfactory according to the following criteria. Single-surface restorations will be considered satisfactory when scored as 0 (restoration present and satisfactory), 1 (restoration present, with a slight marginal defect and/or surface wear of less than 0.5 mm in depth, with no need for repair), or 7 (restoration present, with gradual wear involving larger areas of the restoration but less than 0.5 mm in depth at the deepest point, with no need for repair), according to Frencken et al. (1996). Multiple-surface restorations will be considered satisfactory when scored as 00 (restoration present and satisfactory) or 10 (restoration present, with a slight marginal defect and/or surface wear of less than 0.5 mm in depth, with no need for repair), according to Rôlevald et al. (2006).	24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment success	Treatment success at 24 months will be assessed as a binary outcome. All participants will be clinically evaluated at 24 months, and each treated tooth will be classified as either successful or unsuccessful. Treatment will be considered successful when the treated tooth requires no operative reintervention during the 24-month follow-up period and remains asymptomatic, according to the clinical criteria described above. Natural exfoliation of the treated tooth during the follow-up period will also be considered a successful outcome. Treatment failure will be defined as the need for operative reintervention due to disease progression or treatment failure, including endodontic treatment or extraction.	24 months
Parents' and Child's Preference	Before randomization, parents or guardians and the child will receive a standardized explanation of the two therapeutic approaches under investigation (replacement and repair of restorations). To aid comprehension, illustrative images generated by artificial intelligence will be presented, depicting each procedure in a standardized manner. Parents or guardians and the child will then be asked: "If you could choose, which treatment would you prefer?" Responses will be recorded as: replacement, repair, or no preference.	Before randomization and prior to treatment
Treatment Time	The total treatment time will be measured by a research assistant using a digital stopwatch. Timing will start at the beginning of the clinical intervention and stop immediately after its completion. Time will be recorded and expressed in minutes (min).	From the beginning to the completion of the treatment procedure
Child's Perception	The child's perception of the treatment will be assessed immediately after completion of the procedure using the Facial Image Scale (FIS). The scale will be presented by the research assistant, in the absence of the operator, in order to minimize the professional's influence on the response. The child will be asked to indicate the image that best represents how they felt during the treatment, following the question: "How did you feel during the treatment?" The FIS consists of five facial images ranging from a very happy to a very sad expression, allowing assessment of the child's acceptance of the experience.	Immediately after the procedure (Day 0)
Parents'/Guardians' Satisfaction	Immediately after completion of the treatment, parents or guardians will answer the following question: "How satisfied are you with the treatment performed on your child?" The response will be recorded on a five-point Likert scale, ranging from very dissatisfied to very satisfied.	Immediately after the procedure (Day 0)
Parents'/Guardians' Willingness to Choose the Treatment Again	At 30 days after the procedure, parents or guardians will be presented again with illustrative images of the two therapeutic approaches, accompanied by the same standardized explanation used in the initial assessment. They will then be asked: "If you could choose again, which treatment would you choose for your child?" Responses will be recorded as repair, replacement, or no preference.	30 days after the procedure
Cost-effectiveness	Additionally, a cost-effectiveness analysis will be conducted comparing the repair and replacement of defective restorations in primary molars over 24 months of follow-up. Restoration survival over this period will be used as the effectiveness measure for the economic analysis. The analysis will adopt the perspective of the Brazilian public health system and will consider only direct treatment costs.	24 months
Treatment Cost	The direct costs associated with the repair and replacement of restorations will be compared, considering the clinical treatment time and materials actually used in each procedure. Treatment time will be measured by a research assistant who is not involved in performing the interventions and will be used to estimate the dental professional's labor cost based on the cost per hour of professional work. Material costs will be estimated based on the actual amount consumed during each procedure and the prices obtained from three quotations from different suppliers, with the mean value of the quotations used for cost calculation. Costs will be expressed in Brazilian reais (BRL), based on the prices prevailing during the study period.	Immediately after the procedure (Day 0)

Collaborators and Investigators

• Sponsor: University of Sao Paulo
• Investigators: Principal Investigator: Camila C Cabral, PhD, University of Sao Paulo

Study record dates

Study Major Dates

• Study Start (Estimated): October 7, 2026
• Primary Completion (Estimated): April 1, 2029
• Study Completion (Estimated): April 1, 2029

Study Registration Dates

• First Submitted: September 4, 2026
• First Submitted That Met QC Criteria: September 4, 2026
• First Posted (Actual): September 10, 2026

Study Record Updates

• Last Update Posted (Actual): September 10, 2026
• Last Update Submitted That Met QC Criteria: September 4, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Child; Dental Restoration, Permanent; Tooth, Deciduous; Dental Restoration Failure; Glass Ionomer Cements;; Randomized Controlled Trial
• Additional Relevant MeSH Terms: Stomatognathic Diseases; Tooth Diseases; Tooth Demineralization; Dental Caries
• Other Study ID Numbers: RepairPEDO

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymized individual participant data (IPD) collected from parents and/or caregivers will be shared, including demographic and study-related data, treatment preference, treatment satisfaction, willingness to choose the treatment again, and other participant-level outcome data collected during the study. All data will be fully anonymized prior to sharing to prevent identification of participants or disclosure of sensitive information.
• IPD Sharing Time Frame: Start date: After publication of the study results End date: No end date
• IPD Sharing Access Criteria: Anonymized individual participant data and the study protocol will be publicly accessible to researchers and other interested users through the designated public data repository. Access will be unrestricted, subject to the repository's terms of use. Only fully anonymized data will be made available, with no information that could reasonably identify individual participants.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No