Glass Fiber-Reinforced Composite Resin Versus Band-and-Loop Space Maintainers in Children: A Split-Mouth Clinical Study

Premature loss of primary molars may result in undesirable tooth movement, arch length reduction, and subsequent malocclusion. Space maintainers are routinely used to preserve arch integrity until eruption of the permanent successor. The conventional band-and-loop (B&L) appliance is considered the standard fixed space maintainer; however, it requires laboratory fabrication, multiple clinical visits, and may be associated with cement failure and esthetic limitations.

Glass fiber-reinforced composite resin (GFRCR) space maintainers have emerged as a minimally invasive, esthetic alternative that can be fabricated directly in a single clinical visit without laboratory procedures. Nevertheless, evidence regarding their long-term clinical performance remains limited and inconsistent.

This prospective split-mouth comparative clinical trial will enroll 20 children aged 5-8 years presenting with bilateral premature loss of comparable primary molars at the Pediatric Dentistry Clinic, Faculty of Dentistry, Najran University, Saudi Arabia. Each participant will receive a GFRCR space maintainer in one quadrant (test intervention) and a conventional B&L appliance in the contralateral quadrant (control intervention), allowing each child to serve as his or her own control and minimizing inter-individual variability.

Before appliance placement, all participants will undergo comprehensive clinical and radiographic examinations, professional oral prophylaxis, and any required restorative treatment. Clinical follow-up examinations will be performed after 3, 6, and 9 months.

The primary outcome is appliance retention (survival).

Secondary outcomes include:

Gingival health around the abutment teeth (Gingival Index). Development of dental caries (International Caries Detection and Assessment System, ICDAS).

Preservation of extraction space measured using a Boley gauge.

Statistical analyses will be performed using paired statistical methods appropriate for the split-mouth design, including the McNemar test for paired categorical outcomes and the Log-rank test for appliance survival analysis. Statistical significance will be established at p < 0.05.

This study will provide clinical evidence regarding the effectiveness of esthetic glass fiber-reinforced composite resin space maintainers compared with the conventional band-and-loop appliance and may support their wider adoption in pediatric dental practice.

Inclusion criteria

• Children aged 5-8 years. Bilateral premature loss of comparable primary molars indicated for extraction or recently extracted.

No measurable space loss at the extraction sites. Presence of suitable mesial and distal abutment teeth adjacent to the edentulous space.

Buccal surfaces of abutment teeth free of dental caries. Class I occlusion or normal primary molar relationship. Presence of succedaneous permanent teeth with no more than one-half of root formation.

Root resorption of the abutment teeth involving less than one-third of the root length.

Presence of the bony crypt over the succedaneous tooth germ. Written informed consent obtained from a parent or legal guardian.

Exclusion criteria

• Existing space loss at the extraction site. Pathological lesions involving the jaws or teeth. Malocclusion or abnormal oral musculature. Systemic diseases or medical conditions affecting dental treatment. Abutment teeth with dental caries or inadequate structure for appliance placement.

Root resorption of abutment teeth exceeding one-third of the root length. Advanced development or absence of the permanent successor. Inability to attend scheduled follow-up visits or lack of parental consent.