Zirconia and Bioflx Crowns for Primary Anterior Teeth

Clinical Outcomes of Prefabricated Zirconia and Bioflx Crowns for Restoring Primary Maxillary Anterior Teeth: A Randomized Controlled Trial

This parallel-group randomized controlled trial will compare the clinical performance of prefabricated zirconia and Bioflx crowns for restoring primary maxillary anterior teeth in children aged 3 to 5 years. Eligible participants will be randomly assigned in a 1:1 ratio to receive either a zirconia crown or a Bioflx crown.

Clinical outcomes will be assessed at 3, 6, and 12 months after crown placement. Evaluations will include gingival health, plaque accumulation, wear of the opposing tooth, crown retention, and clinical symptoms of the treated tooth. Parent satisfaction with the esthetic outcome will also be evaluated.

The study aims to provide comparative clinical evidence on the effectiveness of zirconia and Bioflx crowns for restoration of primary maxillary anterior teeth.

Study Overview

• Status: Active, not recruiting
• Conditions: Dental Caries; Tooth Hypomineralization
• Intervention / Treatment: Other: Zirconia Crown; Other: Bioflx Crown

Detailed Description

Primary maxillary anterior teeth are important for esthetics, speech, mastication, and maintenance of normal oral function in young children. Extensive caries and hypomineralization may result in substantial loss of tooth structure and require full-coverage restoration. Prefabricated zirconia and Bioflx crowns are esthetic restorative options; however, comparative clinical evidence for their use in primary maxillary anterior teeth remains limited.

This study is a parallel-group randomized controlled clinical trial conducted in children aged 3 to 5 years who require full-coverage restoration of primary maxillary anterior teeth. Eligible participants must have an opposing tooth and at least two carious surfaces on the target tooth, caries involving the incisal edge, or discoloration associated with hypomineralization. Children with acute systemic disease, allergy to the luting cement, pulp exposure before treatment, inadequate remaining tooth structure, severe bruxism or deep bite, advanced root resorption, previous trauma affecting the target tooth, or other predefined exclusion criteria will not be enrolled.

A minimum of 120 teeth will be included. Randomization will be performed at the participant level using a computer-generated variable block sequence with a 1:1 allocation ratio. Allocation concealment will be maintained using sequentially numbered opaque sealed envelopes.

Participants will receive either prefabricated zirconia crowns or prefabricated Bioflx crowns. Clinical and radiographic examinations will be completed before treatment. Crown preparation and cementation procedures will be standardized, and Fuji IX Extra glass ionomer cement will be used for crown placement.

The primary outcome will be gingival health at 6 months after crown placement. Secondary outcomes will include plaque accumulation, wear of opposing teeth, crown retention, clinical symptoms of crowned teeth, and parent satisfaction with crown esthetics. Follow-up assessments will be performed at 3, 6, and 12 months. Statistical analyses will account for clustering when more than one tooth is included from the same participant.

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Vietnam
  • Huế, Vietnam, 530000
    • Faculty of Odonto-Stomatology, University of Medicine and Pharmacy, Hue University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Children aged 3 to 5 years.
• Children requiring full-coverage restoration of one or more primary maxillary anterior teeth.
• Presence of an opposing tooth.
• Target tooth with at least two carious surfaces, caries involving the incisal edge, or discoloration associated with hypomineralization.
• Written informed consent from a parent or legal guardian and willingness to comply with treatment and follow-up visits.

Exclusion Criteria:

• Allergy to Fuji IX Extra glass ionomer cement.
• Acute systemic disease.
• Crowded teeth affecting crown placement.
• Pulp exposure before treatment.
• Inadequate remaining clinical crown structure after tooth preparation.
• Absence of an opposing tooth.
• Bruxism or deep bite.
• Tooth close to exfoliation or root resorption exceeding one-half of the root length.
• Caries limited to a single surface without proximal involvement.
• History of trauma affecting the target tooth.

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
Active Comparator: Zirconia; Participants receive prefabricated zirconia crowns for restoration of indicated primary maxillary anterior teeth. Teeth are prepared using a standardized clinical protocol, and crowns are cemented with Fuji IX Extra glass ionomer cement.	Other: Zirconia Crown; Prefabricated zirconia crowns manufactured by Shinhung, Republic of Korea, will be used to restore eligible primary maxillary anterior teeth. Tooth preparation, crown selection, cementation with Fuji IX Extra glass ionomer cement, removal of excess cement, and post-treatment instructions will follow a standardized protocol.
Experimental: Bioflx; Participants receive prefabricated Bioflx crowns for restoration of indicated primary maxillary anterior teeth. Teeth are prepared using a standardized clinical protocol, and crowns are cemented with Fuji IX Extra glass ionomer cement.	Other: Bioflx Crown; Prefabricated Bioflx crowns manufactured by Kids-e-Dental, India, will be used to restore eligible primary maxillary anterior teeth. Tooth preparation, crown selection, cementation with Fuji IX Extra glass ionomer cement, removal of excess cement, and post-treatment instructions will follow a standardized protocol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gingival index	Gingival status adjacent to crowned primary maxillary anterior teeth, assessed using the Löe and Silness Gingival Index. Lower scores indicate better gingival health.	3, 6, and 12 months after crown placement
Fluorescent Plaque Index	Plaque accumulation on crowned primary maxillary anterior teeth, assessed using QrayScan Plus according to the Fluorescent Plaque Index (FPI; 0-5). Higher scores indicate greater plaque accumulation.	3, 6, and 12 months after crown placement
Opposing Tooth Wear	Wear of the tooth opposing the crowned primary maxillary anterior tooth, assessed clinically on a 0-4 ordinal scale. Higher scores indicate greater enamel and dentin loss.	3, 6, and 12 months after crown placement
Crown Retention	Retention status of the prefabricated crown, categorized as retained or loose/lost.	3, 6, and 12 months after crown placement
Clinical Status of Crowned Teeth	Clinical status of teeth restored with prefabricated crowns, categorized as asymptomatic, sensitive, mobile, painful, or swollen.	3, 6, and 12 months after crown placement

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Parental Satisfaction	Parental satisfaction with the esthetic outcome of crown restoration, assessed using a 4-point Likert scale for crown shape, color, alignment, interdental spacing, perceived crowding, and other esthetic abnormalities. Lower scores indicate greater satisfaction.	6 and 12 months after crown placement

Collaborators and Investigators

• Sponsor: Hue University of Medicine and Pharmacy

Publications and helpful links

General Publications

• Gill A, Garcia M, Won An S, Scott J, Seminario AL. Clinical Comparison of Three Esthetic Full-Coverage Restorations in Primary Maxillary Incisors at 12 Months. Pediatr Dent. 2020 Sep 15;42(5):367-372.

Study record dates

Study Major Dates

• Study Start (Actual): January 4, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: July 2, 2026
• First Submitted That Met QC Criteria: July 2, 2026
• First Posted (Actual): July 9, 2026

Study Record Updates

• Last Update Posted (Actual): July 9, 2026
• Last Update Submitted That Met QC Criteria: July 2, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Zirconia Crowns; Bioflx Crowns; Primary Maxillary Anterior Teeth
• Additional Relevant MeSH Terms: Developmental Defects of Enamel; Stomatognathic Diseases; Tooth Diseases; Stomatognathic System Abnormalities; Congenital Abnormalities; Tooth Demineralization; Tooth Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Dental Enamel Hypomineralization; Dental Caries
• Other Study ID Numbers: H2025/387

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No