Carious Primary MolarsNCT06856070
Retention of Bioflx Crowns Compared to Zirconia Crowns on Primary Molars
A study testing (Group A: Preformed Bioflx crown) and (Group B: Preformed Zirconia crown) in people with Carious Primary Molars, run by Cairo University at 2 sites in Egypt.
Trial summary
The goal of this clinical trial is to evaluate the retention and resistance to dislodgment of Bioflx crowns compared to zirconia crowns in the restoration of primary molars. The main question[s] it aims to answer : Is there a difference in the retention and resistance to dislodgement of BioFlx crowns compared to… Read more about this study
- Who is it for?
- Ages 4 to 8 yearsHealthy volunteers can take part
- Conditions the study is for
- Carious Primary Molars
- What is being tested?
- (Group A: Preformed Bioflx crown) and (Group B: Preformed Zirconia crown)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 2 sitesEgypt
- Study dates
- 30 Jun 2025to Feb 2026
- 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 8 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Children aged between 4 and 8 years with primary molar that needs to be covered by crown.
- Children who can cooperate sufficiently for the duration of the procedure, as assessed by behavior management techniques.
- Medically healthy children (ASA I or II according to the American Society of Anesthesiologists classification).
- Children whose parent or guardian are willing to sign an informed consent.
- Children whose parent or guardian are willing to comply with follow-up visits. -
Who cannot join
- The exclusion criteria
- Molars with severe structural loss that may compromise crown retention.
- Children with poor oral hygiene that may contribute to higher plaque levels and affect the clinical outcomes of the crown restorations.
- Children with history of allergies; Known allergies to dental local anesthesia or to the materials used in Bioflx crowns.
- Children with any systemic conditions or disabilities that may affect their ability to participate in the study.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Egypt2 sites
Faculty of Dentistry, Cairo University.
Cairo, Giza Governorate, 12613
noura jamal elnoor mohamed, B.DSc, 00201148788375, nourajamal997@gmail.com
Faculty of Dentistry, Cairo University.
Cairo
About this study
Official title: Evaluation of Retention and Resistance to Dislodgement of Bioflx Crowns Compared to Zirconia Crowns on Primary Molars
The goal of this clinical trial is to evaluate the retention and resistance to dislodgment of Bioflx crowns compared to zirconia crowns in the restoration of primary molars. The main question[s] it aims to answer : Is there a difference in the retention and resistance to dislodgement of BioFlx crowns compared to zirconia crowns in the restoration of primary molars?" The study will also assess the clinical performance of both types of crowns in terms of occlusal wear, gingival health, preparation time, as well as child and parental satisfaction.
Read the detailed description
Primary molars play a significant role in maintaining oral function, esthetics, and space for permanent teeth, therefore, restoring decayed primary molars is a critical aspect of pediatric dentistry. Stainless steel crowns have been the standard restorative material for primary molars due to their clinical success, retention, and durability. However, the aesthetic limitations of SSCs, have been problematic, especially when patients seek more esthetically acceptable treatment options.In an attempt to address the aesthetic limitations of stainless-steel crowns, pre-veneered stainless-steel crowns were introduced featuring a thin layer of composite resin or ceramic on the outside to improve their appearance. While they provided a better aesthetic than pure stainless steel, their limitations included a tendency to wear down over time, difficulty in matching natural tooth color, and the potential for the veneer to chip or detach.Recently, zirconia crowns are preferred over pre-veneered stainless-steel crowns for their esthetic superiority, biocompatibility, and resistance to wear. They demonstrate excellent retention and durability but require significant tooth preparation, which may compromise tooth structure. Despite their advantages, zirconia crowns posed challenges such as increased cost, more complex preparation techniques, and concerns about their brittleness under certain conditions. Moreover, zirconia crowns may not be suitable for all cases, especially those involving less mineralized or structurally compromised primary molars .In 2021, Kids-e-Dental LLP introduced Bioflx Crowns and claimed as the first flexible, durable, and esthetic preformed crown for primary molars. Bioflx Crowns are monochromatic, metal-free, tooth-colored crowns made up of high-strength resin polymer used in the medical device industry having high strength, flexibility, and durability. These crowns are autoclavable and are like SSC in tooth preparation as claimed by the manufacturer. Their flexibility and snap-fit technology aim to improve retention while minimizing trauma during placement.
It is important to mention that retention is a crucial factor for the success of any dental crown. An inadequate retention can lead to crown displacement, necessitating re-treatment, and ultimately affect the long-term health of the primary tooth. While studies have demonstrated the superior esthetic properties of materials like Bioflx crowns, their clinical performance, particularly retention rates and overall longevity, require further evaluation in direct comparison to zirconia crowns .Thus, this trial aims to fill the gap in current knowledge and provide clinicians with evidence to support the choice of crown material based on retention performance, which is critical to the long-term success of pediatric restorations.
- Conditions
- Carious Primary Molars
- Being tested
- (Group A: Preformed Bioflx crown), (Group B: Preformed Zirconia crown)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
(Group A: Preformed Bioflx crown)Other
prepartion:1.The mesiodistal width of the tooth will be measured using calipers and a closely fitted crown will be selected based on the measurements.
- The tooth will be prepared similarly to stainless steel crowns (SSCs):
- Occlusal reduction of approximately 1-1.5 mm will be done using a diamond bur.Mesial and distal reduction of no more than 1 mm will be performed using a No. 169L diamond bur.Depending on the tooth anatomy, either no buccal and lingual reduction will be needed, or a minimal reduction will be done. 3.All sharp line angles and corners will be smoothed to ensure proper crown fit. 4.The crown will be checked for proper fit before cementation. It will be positioned to extend 1 mm below the gingival margin. 5.The crown will be cemented using luting glass ionomer cement (GIC). The crown will be held with firm, constant pressure until the cement sets initially. 6.The marginal fit will be evaluated, and necessary adjustments will be made. 7.The occlusion will be checked,
(Group B: Preformed Zirconia crown)Other
- Crown Selection: The mesiodistal dimension of the corresponding tooth will be measured . to select the appropriate size.2. Occlusal Reduction: The marginal ridge of adjacent teeth will be used as a reference point and a 1.5-2 mm of occlusal reduction will be performed to allow proper crown seating.3. Bucco-Lingual Reduction: The bucco-lingual wall will be reduced by approximately 1-1.5 mm using a flame-shaped diamond bur.4. Interproximal Reduction: 1 mm of interproximal reduction will be performed using a flame-shaped diamond bur such as a .368 or .330 tapered carbide bur.5. Feather Margin Preparation: Subgingival reduction of 1-2 mm will be done using a flame-shaped diamond bur, creating a feathered margin to achieve a passive fit.6. Trial Fitting of the Crown: The crown will be tried in to ensure proper adaptation. until the crown fits passively and extends sub gingivally by 1-2 mm wit.7. Glass ionomer cement will be used for cementation.
| Study group | Role | What they receive |
|---|---|---|
| (Group A: Preformed Bioflx crown) | Experimental | Kids-e-Dental LLP (ANDHERI, MUMBAI, INDIA) introduced Bioflx Crowns and claimed as the first flexible, durable, and esthetic preformed crown for primary molars. Bioflx Crowns are monochromatic, metal-free, tooth-colored crowns made up of high-strength resin polymer used in the medical device industry having high strength, flexibility, and durability. These crowns are autoclavable and are like SSC in tooth preparation as claimed by the manufacturer. Their flexibility and snap-fit technology aim to improve retention while minimizing trauma during placement Receives: Other: (Group A: Preformed Bioflx crown) |
| (Group B: Preformed zirconia crown) | Experimental | Zirconia crowns have been widely used in pediatric dentistry due to their high esthetic value, biocompatibility, and strength. Studies have shown that zirconia crowns exhibit superior retention due to their passive fit and resistance to fracture. Receives: Other: (Group B: Preformed Zirconia crown) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Retention
Method of Measurement:Modified United States Public Health System criteria:Alpha: Intact Bravo:Chipped/loss of material Charlie: Complete loss of crown
Measured: follow-up:T (Time): 6months interval T0: 0 T1: 3month T2: 6month
Secondary outcomes (4)
Occlusal wear of crown
Measure by Modified United States Public Health System criteria:
Alpha: Occlusal surface intact. Bravo: Wear of occlusal surface without tooth surface exposure Charlie: Wear of occlusal surface with
Measured: T (Time): 6months interval T0: 0 T1: 3 month T2: 6month
Gingival health
Measure by: Gingival index:
0: healthy gum
- mild discoloration and edematous gingiva no bleeding on probing
- red oedematous and shiny gingiva bleeding on probing
- red oedematous and ulceration gingiva spontaneous bleeding
Measured: T (Time): 6months interval T0: 0 T1: 3month T2: 6month
child and parental satisfaction
Measure by: 5-Point likert's scale / Questionnaire:Ordinary or N/A
Measured: T (Time): 6months interval T0: 0T1: 3month T2: 6month
Preparation time
Measure by :Stopwatch per minutes.
Measured: baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Mar 2025
- Study start30 Jun 2025 (estimated)
- Primary completionDec 2025 (estimated)
- Study completionFeb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Carious Primary MolarsStudies of the same condition, open and under way.
- More trials run by Cairo UniversityThe sponsor's other registered studies.
- 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
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Cairo University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, noura jamal elnoor mohamed, Cairo University
- Investigators
- Dr.manal ahmed elshiekh Prof, Ph.D, Study director, Cairo University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06856070
- Sponsor's protocol ID
- RR-BFC Vs ZR
- Status last verified
- Feb 2025
- First submitted
- 25 Feb 2025
- Last updated
- 4 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Rahate I, Fulzele P, Thosar N. Comparative evaluation of clinical performance, child and parental satisfaction of Bioflx, zirconia and stainless steel crowns in pediatric patients. F1000Res. 2023 Dec 21;12:756. doi: 10.12688/f1000research.133464.2. eCollection 2023.
PubMed 38911945Patil 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 4 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Retention and Resistance to Dislodgement of Bioflx Crowns Compared to Zirconia Crowns on Primary Molars
- ClinicalTrials.gov ID
- NCT06856070
- Acronym / sponsor ID
- RR-BFC Vs ZR
- Conditions
- Carious Primary Molars
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Cairo UniversityUniversity, hospital or other
- Study start
- 30 Jun 2025 (estimated)
- Primary completion
- Dec 2025 (estimated)
- Study completion
- Feb 2026 (estimated)
- First posted
- 4 Mar 2025 (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 evaluate the retention and resistance to dislodgment of Bioflx crowns compared to zirconia crowns in the restoration of primary molars. The main question[s] it aims to answer : Is there a difference in the retention and resistance to dislodgement of BioFlx crowns compared to zirconia crowns in the restoration of primary molars?" The study will also assess the clinical performance of both types of crowns in terms of occlusal wear, gingival health, preparation time, as well as child and parental satisfaction.
Detailed description
Primary molars play a significant role in maintaining oral function, esthetics, and space for permanent teeth, therefore, restoring decayed primary molars is a critical aspect of pediatric dentistry. Stainless steel crowns have been the standard restorative material for primary molars due to their clinical success, retention, and durability. However, the aesthetic limitations of SSCs, have been problematic, especially when patients seek more esthetically acceptable treatment options.In an attempt to address the aesthetic limitations of stainless-steel crowns, pre-veneered stainless-steel crowns were introduced featuring a thin layer of composite resin or ceramic on the outside to improve their appearance. While they provided a better aesthetic than pure stainless steel, their limitations included a tendency to wear down over time, difficulty in matching natural tooth color, and the potential for the veneer to chip or detach.Recently, zirconia crowns are preferred over pre-veneered stainless-steel crowns for their esthetic superiority, biocompatibility, and resistance to wear. They demonstrate excellent retention and durability but require significant tooth preparation, which may compromise tooth structure. Despite their advantages, zirconia crowns posed challenges such as increased cost, more complex preparation techniques, and concerns about their brittleness under certain conditions. Moreover, zirconia crowns may not be suitable for all cases, especially those involving less mineralized or structurally compromised primary molars .In 2021, Kids-e-Dental LLP introduced Bioflx Crowns and claimed as the first flexible, durable, and esthetic preformed crown for primary molars. Bioflx Crowns are monochromatic, metal-free, tooth-colored crowns made up of high-strength resin polymer used in the medical device industry having high strength, flexibility, and durability. These crowns are autoclavable and are like SSC in tooth preparation as claimed by the manufacturer. Their flexibility and snap-fit technology aim to improve retention while minimizing trauma during placement.
It is important to mention that retention is a crucial factor for the success of any dental crown. An inadequate retention can lead to crown displacement, necessitating re-treatment, and ultimately affect the long-term health of the primary tooth. While studies have demonstrated the superior esthetic properties of materials like Bioflx crowns, their clinical performance, particularly retention rates and overall longevity, require further evaluation in direct comparison to zirconia crowns .Thus, this trial aims to fill the gap in current knowledge and provide clinicians with evidence to support the choice of crown material based on retention performance, which is critical to the long-term success of pediatric restorations.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| (Group A: Preformed Bioflx crown) | Experimental | Other: (Group A: Preformed Bioflx crown)Kids-e-Dental LLP (ANDHERI, MUMBAI, INDIA) introduced Bioflx Crowns and claimed as the first flexible, durable, and esthetic preformed crown for primary molars. Bioflx Crowns are monochromatic, metal-free, tooth-colored crowns made up of high-strength resin polymer used in the medical device industry having high strength, flexibility, and durability. These crowns are autoclavable and are like SSC in tooth preparation as claimed by the manufacturer. Their flexibility and snap-fit technology aim to improve retention while minimizing trauma during placement |
| (Group B: Preformed zirconia crown) | Experimental | Other: (Group B: Preformed Zirconia crown)Zirconia crowns have been widely used in pediatric dentistry due to their high esthetic value, biocompatibility, and strength. Studies have shown that zirconia crowns exhibit superior retention due to their passive fit and resistance to fracture. |
Who may qualify
- Ages
- 4 to 8 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- Children aged between 4 and 8 years with primary molar that needs to be covered by crown.
- Children who can cooperate sufficiently for the duration of the procedure, as assessed by behavior management techniques.
- Medically healthy children (ASA I or II according to the American Society of Anesthesiologists classification).
- Children whose parent or guardian are willing to sign an informed consent.
- Children whose parent or guardian are willing to comply with follow-up visits. -
Key exclusion criteria (5 listed)
- The exclusion criteria
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 |
|---|---|---|
| (Group A: Preformed Bioflx crown)prepartion:1.The mesiodistal width of the tooth will be measured using calipers and a closely fitted crown will be selected based on the measurements. 2. The tooth will be prepared similarly to stainless steel crowns (SSCs): * Occlusal reduction of approximately 1-1.5 mm will be done using a diamond bur.Mesial and distal reduction of no more than 1 mm will be performed using a No. 169L diamond bur.Depending on the tooth anatomy, either no buccal and lingual reduction will be needed, or a minimal reduction will be done. 3.All sharp line angles and corners will be smoothed to ensure proper crown fit. 4.The crown will be checked for proper fit before cementation. It will be positioned to extend 1 mm below the gingival margin. 5.The crown will be cemented using luting glass ionomer cement (GIC). The crown will be held with firm, constant pressure until the cement sets initially. 6.The marginal fit will be evaluated, and necessary adjustments will be made. 7.The occlusion will be checked, | Other | (Group A: Preformed Bioflx crown) |
| (Group B: Preformed Zirconia crown)1. Crown Selection: The mesiodistal dimension of the corresponding tooth will be measured . to select the appropriate size.2. Occlusal Reduction: The marginal ridge of adjacent teeth will be used as a reference point and a 1.5-2 mm of occlusal reduction will be performed to allow proper crown seating.3. Bucco-Lingual Reduction: The bucco-lingual wall will be reduced by approximately 1-1.5 mm using a flame-shaped diamond bur.4. Interproximal Reduction: 1 mm of interproximal reduction will be performed using a flame-shaped diamond bur such as a .368 or .330 tapered carbide bur.5. Feather Margin Preparation: Subgingival reduction of 1-2 mm will be done using a flame-shaped diamond bur, creating a feathered margin to achieve a passive fit.6. Trial Fitting of the Crown: The crown will be tried in to ensure proper adaptation. until the crown fits passively and extends sub gingivally by 1-2 mm wit.7. Glass ionomer cement will be used for cementation. | Other | (Group B: Preformed zirconia crown) |
Primary outcome
Retention
Time frame: follow-up:T (Time): 6months interval T0: 0 T1: 3month T2: 6month
Method of Measurement:Modified United States Public Health System criteria:Alpha: Intact Bravo:Chipped/loss of material Charlie: Complete loss of crown
4 secondary outcomes
Occlusal wear of crown
Time frame: T (Time): 6months interval T0: 0 T1: 3 month T2: 6month
Gingival health
Time frame: T (Time): 6months interval T0: 0 T1: 3month T2: 6month
child and parental satisfaction
Time frame: T (Time): 6months interval T0: 0T1: 3month T2: 6month
Preparation time
Time frame: baseline
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 4 Mar 2025.
- Background: PubMed 38911945Rahate I, Fulzele P, Thosar N. Comparative evaluation of clinical performance, child and parental satisfaction of Bioflx, zirconia and stainless steel crowns in pediatric patients. F1000Res. 2023 Dec 21;12:756. doi: 10.12688/f1000research.133464.2. eCollection 2023.
- 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: No
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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.
Dr.manal ahmed elshiekh Prof, Ph.D study director
Cairo University
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing (Group A: Preformed Bioflx crown) and (Group B: Preformed Zirconia crown) in people with Carious Primary Molars, run by Cairo University at 2 sites in Egypt.
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 5 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: opening soon, as of the sponsor's last update on 4 Mar 2025. 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 Egypt. 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?
Contact noura jamal elnoor mohamed, bachelor of dental science (00201148788374, nourajamal997@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Retention (time frame: follow-up:T (Time): 6months interval T0: 0 T1: 3month T2: 6month). 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 NCT06856070, which also lists 2 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 4 Mar 2025.