Severely Decayed Primary Molars Requiring Full-Coverage CrownsNCT07357402
Clinical Outcomes and Satisfaction of Stainless Steel vs Bioflx Crowns in Primary Molars
A study testing Stainless Steel Crown and Bioflx crown in people with Severely Decayed Primary Molars Requiring Full-Coverage Crowns, run by PHAM LE ANH THY at 2 sites in Vietnam.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 4 to 10 years
- Conditions the study is for
- Severely Decayed Primary Molars Requiring Full-Coverage Crowns
- What is being tested?
- Stainless Steel Crown and Bioflx crown
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 2 sitesVietnam
- Study dates
- 1 Aug 2025to 1 Oct 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 4 to 10 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
2 sites in 1 country.
Vietnam2 sites
University of Medicine and Pharmacy at Ho Chi Minh City
Ho Chi Minh City, 700000
University of Medicine and Pharmacy at Ho Chi Minh City
Ho Chi Minh City
About this study
Official title: Comparison of Clinical Outcomes, Parent and Child Satisfaction Between Stainless Steel Crowns and Prefabricated Hybrid (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:
Read more
- 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?
- 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:
- Receive one Bioflx crown and one stainless steel crown on similar teeth on opposite sides of the mouth.
- Visit the clinic for two separate appointments, spaced 1 to 2 weeks apart, to have the crowns placed.
- Return for checkups at 3 months and 6 months so researchers can examine the health of the teeth and gums.
- Answer questions about how happy they are with the appearance and feel of the crowns.
Read the detailed description
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?
- Being tested
- Stainless Steel Crown, Bioflx crown
- Keywords
- Stainless steel crowns, Bioflx crowns, Primary molars, Split-mouth study, Parental and child satisfaction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Stainless Steel CrownDevice
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 crownDevice
Bioflx crowns are prefabricated tooth-colored polymer crowns designed to improve esthetics compared with conventional stainless steel crowns
| Study group | Role | What they receive |
|---|---|---|
| Stainless steel crown | Active comparator | Participants receive a prefabricated stainless steel crown placed on a primary molar according to standard pediatric dental procedures. The crown is selected, adapted, and cemented following conventional clinical protocols and serves as the standard treatment comparator in this study. Receives: Device: Stainless Steel Crown |
| Bioflx crown | Experimental | Participants receive a prefabricated Bioflx crown placed on a primary molar using manufacturer-recommended techniques. The crown is selected and cemented following standardized clinical procedures and is evaluated as the experimental intervention for clinical performance and patient-related outcomes. Receives: Device: Bioflx crown |
What is being measured
The primary outcome is the main question the study is designed to answer.
- 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
- 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.
Measured: - 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
Secondary outcomes (1)
parent and child satisfaction
- 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.
Measured: From immediately after crowns placement through the 3-month and 6-month follow-up visits.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Jan 2026
- Study start1 Aug 2025
- Primary completion1 Jul 2026 (estimated)
- Study completion1 Oct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Severely Decayed Primary Molars Requiring Full-Coverage CrownsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- The study is designed as a randomized split-mouth clinical trial. Each child will receive both types of crowns on two similar teeth on opposite sides of the mouth. One side is randomly assigned to receive a stainless steel crown, and the other side receives a Bioflx crown. The placement of the two crowns is performed in two separate appointments, with an interval of 1 to 2 weeks between them. This approach allows the child to adapt to the new occlusion (bite) after the first crown is placed, ensuring a more stable result before the second procedure.
- Masking
- None (open label)
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- PHAM LE ANH THY
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, PHAM LE ANH THY, University of Medicine and Pharmacy at Ho Chi Minh City
- Investigators
- Huong Thi Nguyen Nguyen, PhD, Study chair, Faculty of Dentistry, University of Medicine and Pharmacy at Ho Chi Minh City
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07357402
- Sponsor's protocol ID
- 3526/QĐ-ĐHYD
- Status last verified
- Jan 2026
- First submitted
- 17 Jan 2026
- Last updated
- 22 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Undecided
Publications
Tin BT, Phuong NTM, Anh NTH, Bau TH, Dong TT, Ngoc VTN. Short-Term Clinical Evaluation of Bioflx Crowns for Primary Molar Restoration in Children Aged 4-8 Years in Vietnam: A Pilot Observational Study. Int J Paediatr Dent. 2026 Jan;36(1):187-194. doi: 10.1111/ipd.70039. Epub 2025 Oct 22.
PubMed 41126408Mathew MG, Roopa KB, Soni AJ, Khan MM, Kauser A. Evaluation of Clinical Success, Parental and Child Satisfaction of Stainless Steel Crowns and Zirconia Crowns in Primary Molars. J Family Med Prim Care. 2020 Mar 26;9(3):1418-1423. doi: 10.4103/jfmpc.jfmpc_1006_19. eCollection 2020 Mar.
PubMed 32509626Lopez-Cazaux S, Aiem E, Velly AM, Muller-Bolla M. Preformed pediatric zirconia crown versus preformed pediatric metal crown: study protocol for a randomized clinical trial. Trials. 2019 Aug 24;20(1):530. doi: 10.1186/s13063-019-3559-1.
PubMed 31445509Pozos-Guillen A, Chavarria-Bolanos D, Garrocho-Rangel A. Split-mouth design in Paediatric Dentistry clinical trials. Eur J Paediatr Dent. 2017 Mar;18(1):61-65. doi: 10.23804/ejpd.2017.18.01.13.
PubMed 28494606Patil AS, Jain M, Choubey S, Patil M, Chunawala Y. Comparative evaluation of clinical success of Stainless Steel and Bioflx crowns in primary molar - A 12 month split mouth prospective randomized clinical trial. J Indian Soc Pedod Prev Dent. 2024 Jan 1;42(1):37-45. doi: 10.4103/JISPPD.JISPPD_484_23. Epub 2024 Apr 15.
PubMed 38616425
Study at a glance
From the registry record, last updated by the sponsor on 22 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of Clinical Outcomes, Parent and Child Satisfaction Between Stainless Steel Crowns and Prefabricated Hybrid (Bioflx) Crowns in Primary Molars
- ClinicalTrials.gov ID
- NCT07357402
- Acronym / sponsor ID
- 3526/QĐ-ĐHYD
- Keywords
- Stainless steel crowns, Bioflx crowns, Primary molars, Split-mouth study, Parental and child satisfaction
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- PHAM LE ANH THYUniversity, hospital or other
- Study start
- 1 Aug 2025 (actual)
- Primary completion
- 1 Jul 2026 (estimated)
- Study completion
- 1 Oct 2027 (estimated)
- First posted
- 22 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- 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?
- 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:
- Receive one Bioflx crown and one stainless steel crown on similar teeth on opposite sides of the mouth.
- Visit the clinic for two separate appointments, spaced 1 to 2 weeks apart, to have the crowns placed.
- Return for checkups at 3 months and 6 months so researchers can examine the health of the teeth and gums.
- Answer questions about how happy they are with the appearance and feel of the crowns.
Detailed description
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?
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- The study is designed as a randomized split-mouth clinical trial. Each child will receive both types of crowns on two similar teeth on opposite sides of the mouth. One side is randomly assigned to receive a stainless steel crown, and the other side receives a Bioflx crown. The placement of the two crowns is performed in two separate appointments, with an interval of 1 to 2 weeks between them. This approach allows the child to adapt to the new occlusion (bite) after the first crown is placed, ensuring a more stable result before the second procedure.
| Arm | Type | Receives |
|---|---|---|
| Stainless steel crown | Active comparator | Device: Stainless Steel CrownParticipants receive a prefabricated stainless steel crown placed on a primary molar according to standard pediatric dental procedures. The crown is selected, adapted, and cemented following conventional clinical protocols and serves as the standard treatment comparator in this study. |
| Bioflx crown | Experimental | Device: Bioflx crownParticipants receive a prefabricated Bioflx crown placed on a primary molar using manufacturer-recommended techniques. The crown is selected and cemented following standardized clinical procedures and is evaluated as the experimental intervention for clinical performance and patient-related outcomes. |
Who may qualify
- Ages
- 4 to 10 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (8 listed)
- 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:
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Stainless Steel CrownStainless 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. | Device | Stainless steel crown |
| Bioflx crownBioflx crowns are prefabricated tooth-colored polymer crowns designed to improve esthetics compared with conventional stainless steel crowns | Device | Bioflx crown |
Primary outcome
- 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.
1 secondary outcome
parent and child satisfaction
Time frame: From immediately after crowns placement through the 3-month and 6-month follow-up visits.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Jan 2026.
- Background: PubMed 41126408Tin BT, Phuong NTM, Anh NTH, Bau TH, Dong TT, Ngoc VTN. Short-Term Clinical Evaluation of Bioflx Crowns for Primary Molar Restoration in Children Aged 4-8 Years in Vietnam: A Pilot Observational Study. Int J Paediatr Dent. 2026 Jan;36(1):187-194. doi: 10.1111/ipd.70039. Epub 2025 Oct 22.
- Background: PubMed 32509626Mathew MG, Roopa KB, Soni AJ, Khan MM, Kauser A. Evaluation of Clinical Success, Parental and Child Satisfaction of Stainless Steel Crowns and Zirconia Crowns in Primary Molars. J Family Med Prim Care. 2020 Mar 26;9(3):1418-1423. doi: 10.4103/jfmpc.jfmpc_1006_19. eCollection 2020 Mar.
- Background: PubMed 31445509Lopez-Cazaux S, Aiem E, Velly AM, Muller-Bolla M. Preformed pediatric zirconia crown versus preformed pediatric metal crown: study protocol for a randomized clinical trial. Trials. 2019 Aug 24;20(1):530. doi: 10.1186/s13063-019-3559-1.
- Background: PubMed 28494606Pozos-Guillen A, Chavarria-Bolanos D, Garrocho-Rangel A. Split-mouth design in Paediatric Dentistry clinical trials. Eur J Paediatr Dent. 2017 Mar;18(1):61-65. doi: 10.23804/ejpd.2017.18.01.13.
- Background: PubMed 38616425Patil AS, Jain M, Choubey S, Patil M, Chunawala Y. Comparative evaluation of clinical success of Stainless Steel and Bioflx crowns in primary molar - A 12 month split mouth prospective randomized clinical trial. J Indian Soc Pedod Prev Dent. 2024 Jan 1;42(1):37-45. doi: 10.4103/JISPPD.JISPPD_484_23. Epub 2024 Apr 15.
- Individual participant dataSharing planned: Undecided
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Huong Thi Nguyen Nguyen, PhD study chair
Faculty of Dentistry, University of Medicine and Pharmacy at Ho Chi Minh City
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Stainless Steel Crown and Bioflx crown in people with Severely Decayed Primary Molars Requiring Full-Coverage Crowns, run by PHAM LE ANH THY at 2 sites in Vietnam.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 22 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Vietnam. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
- 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). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07357402, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jan 2026.