Active, Not Recruiting

NCT Number: NCT07357402

Clinical Outcomes and Satisfaction of Stainless Steel vs Bioflx Crowns in Primary Molars

The goal of this clinical trial is to learn if the Bioflx crown (a tooth-colored material) is as effective as the standard stainless steel crown for treating severely decayed baby back teeth in children aged 4 to 10 years old. The study also aims to evaluate parent and child satisfaction with these restorative options.

The main questions it aims to answer are:

1. Is the Bioflx crown as effective as the stainless steel crown in terms of durability, staying in place, and protecting the tooth from new decay? 2. Does the Bioflx crown maintain better gum health and cause less wear on the opposing teeth compared to the stainless steel crown?

Researchers will compare the Bioflx crown to the stainless steel crown to see which material works better to restore tooth function and health.

Participants will:

1. Receive one Bioflx crown and one stainless steel crown on similar teeth on opposite sides of the mouth. 2. Visit the clinic for two separate appointments, spaced 1 to 2 weeks apart, to have the crowns placed. 3. Return for checkups at 3 months and 6 months so researchers can examine the health of the teeth and gums. 4. Answer questions about how happy they are with the appearance and feel of the crowns.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Notify Me

Key information

Conditions

Severely Decayed Primary Molars Requiring Full-Coverage Crowns

Age range

4 year–10 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam

About this study

The standard treatment for fixing severely decayed baby back teeth is the stainless steel crown, which is a durable metal cap. While these metal crowns work very well, many parents and children prefer a more natural, tooth-colored look. This study tests a newer option called the Bioflx crown, which is made of a flexible, tooth-colored material.

The Treatment Process The crowns are placed during two separate visits, usually 1 to 2 weeks apart. It gives the child time to get used to the first crown and ensures their bite is comfortable before the second one is placed. It makes the appointments shorter and easier for the child to handle. The side of the mouth that gets the metal crown and the side that gets the tooth-colored crown is randomized.

How Success is Measured

After the crowns are placed, researchers will check them again at 3 months and 6 months. They will use professional standards to evaluate the effectiveness of the crowns, focusing on:

Durability: Do the crowns stay glued to the teeth and resist wearing down from chewing?
Prevention: Does the new material prevent new cavities from forming at the edges of the crown?
Gum Health: Do the gums around the tooth stay healthy, or do they become red and swollen?
Satisfaction: How do the child and parent feel about the color, size, and shape of the tooth-colored crown compared to the metal one?

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Children with at least two carious primary molars located on both the right and left sides of the dental arch and indicated for crown placement
Children and their parents have ability to communicate in Vietnamese
Primary molars indicated for full-coverage crown restoration, including teeth with:

Multi-surface caries
Extensive caries or enamel-dentin defects
Interproximal caries
High risk of failure with other restorative materials
Teeth following pulpotomy or pulpectomy

Exclusion criteria

Uncooperative children
Presence of psychiatric or neurological disorders affecting communication ability
Malocclusion (crossbite or scissors bite)
Having abnormal parafunctional habits
Teeth with root resorption exceeding one half of the root length

Treatment and study plan

Stainless steel crown

Device

Stainless steel crowns are prefabricated metal crowns that have been widely and long used in pediatric dentistry to restore primary molars with extensive caries or following pulp therapy.

Bioflx crown

Device

Bioflx crowns are prefabricated tooth-colored polymer crowns designed to improve esthetics compared with conventional stainless steel crowns

Primary outcomes

- Clincal outcomes: crown stability; bite discomfort; fit and color changes at the crown edge; crown shape; crown retention; crown wear; wear of the opposing tooth or crown - Oral hygiene and gum health around the crowns

Time frame: - Crown stability, bite discomfort, fit and color at the crown margin, and crown shape were checked after crown placement, at 3 months, and at 6 months follow-up visits. Others were checked at 3, 6 months, except secondary caries was checked at 6 months
- Each clinical parameter was assessed using the modified United States Public Health Service (USPHS) criteria.
- Outcomes were rated on a three-level scale (Alpha, Bravo, Charlie), where Alpha indicates an ideal condition, Bravo an acceptable condition with minor defects, and Charlie an unacceptable condition requiring repair or replacement. For analysis, Alpha and Bravo scores were considered acceptable, while Charlie scores were considered failures.
- Secondary caries were assessed using periapical radiographs, while all other clinical parameters were assessed by dental explorer and documented using photographs (Canon 6D camera).
- This outcome evaluates how clean the teeth are and how healthy the gums are around crowned teeth. Plaque and gum condition were evaluated using standard dental indices (Plaque Index and Gingival Index). Dentists exam by using a periodontal probe at six points around the crowns, and the scores were combined to provide an overall result.

Secondary outcomes

parent and child satisfaction

Time frame: From immediately after crowns placement through the 3-month and 6-month follow-up visits.
- Children's and parents' satisfaction are assessed using two separate questionnaires, both employing a 5-point Likert scale with scores ranging from 1 to 5 (Units on a Scale). For children, a facial expression Likert scale is used.
- The Likert scale levels are defined as follows:
- - Very dissatisfied
- - Dissatisfied
- - Neutral
- - Satisfied
- - Very satisfied
- Higher scores indicate greater satisfaction
- Parent questionnaire includes the following items: size, shape, color of two crowns; child's ability to eat a variety of foods after treatment and overall parental satisfaction.
- Another questionnaire scale based on children ratings of treatment on them consists of five categories, including 1) Appearance of the teeth before crown placement; 2) Crowns have improved the appearance of the child's teeth; 3) The child avoided smiling before crowns; 4) Child smiling after crowns; 5) The oral health of the child improved after crowns.

Sponsors and collaborators

Lead sponsor

PHAM LE ANH THY

Other

Registry information

Official study title

Comparison of Clinical Outcomes, Parent and Child Satisfaction Between Stainless Steel Crowns and Prefabricated Hybrid (Bioflx) Crowns in Primary Molars

Important dates

Study start: 2025
Primary completion: 2026
Study completion: 2027
First posted: Jan 22, 2026
Registry last updated: Jan 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.