Badly Decayed Primary MolarsNCT07156838

Evaluation of Bioflex and Zirconia Crowns Versus Stainless Steel Crowns on Primary Molars: Randomized Controlled Clinical Trial

A study testing bioflex crown, zerconia crown and stainless steel crown in people with Badly Decayed Primary Molars and Preformed Pediatric Posterior Crowns, run by Alexandria University at 1 site in Egypt.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

Search all trials

Trial summary

The goal of this clinical trial is to evaluate the clinical effectiveness of bioflex crowns and zirconia crowns compared to stainless steel crowns when restoring primary molars 45 participant who their ages range between 6 and 8 years participated in this study. Read more about this study

Who is it for?: Ages 6 to 8 yearsHealthy volunteers can take part
Conditions the study is for: Badly Decayed Primary Molars, Preformed Pediatric Posterior Crowns
What is being tested?: bioflex crown, zerconia crown and stainless steel crown
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 45 participants
Where: 1 siteEgypt
Study dates: 10 Feb 2025to 17 Dec 2025
Phase: Interventional
Are there results?: None posted in the registry

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 6 to 8 years
All sexes
Healthy volunteers accepted
Child

Who may be able to join

Children who are free from any systemic disease.
Cooperative children (positive/ definitely positive) according to Frankl's behavior rating scale.
Children with good to fair oral hygiene according to Loe and Silness plaque index.
Primary molars with deep carious lesion, that are indicated for pulpotomy and crown.
Primary molars having two-thirds of root structure left radiographically
Parents' willingness to participate through informed written consent

Who cannot join

Children with oral parafunctional habits.
Primary molars with bifurcation involvement
Presence of abscess or fistula related to the selected tooth
Primary molars with insufficient crown structure

Trial locations and contacts

1 site in 1 country.

Egypt1 site

outpatient clinic of pediatric dentistry -faculty of dentistry- Alexandria university
Alexandria, Azarita

Other trials in Egypt

About this study

The goal of this clinical trial is to evaluate the clinical effectiveness of bioflex crowns and zirconia crowns compared to stainless steel crowns when
restoring primary molars 45 participant who their ages range between 6 and 8 years participated in this study. The participants will be divided into three groups: group (A) for Bioflex crown (n=15), group (B) for Zirconia crown (n=15) and group ( C) for Stainless steel crown(n=15).

The periodontal health will be evaluated using gingival index and plaque index .Clinical success will be assessed according to the Modified United States Public Health Service Evaluation (USPHS) criteria regarding: crown retention ,marginal integrity, surface roughness and color change. Moreover, parental and child satisfaction will be evaluated.

Conditions: Badly Decayed Primary Molars, Preformed Pediatric Posterior Crowns
Being tested: bioflex crown, zerconia crown, stainless steel crown
Keywords: bioflex crown, zerconia crown, stainless steel crown, clinical success

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

bioflex crownOther
A preformed bioflex crown of similar size will be selected. Tooth preparation will be done using a tapered diamond bur to reduce the occlusal surface, including the central groove, by 1-1.5 mm. The proximal surfaces will be prepared by approximately 0.5 mm to clear the contact area, bioflex crown fitting and proper occlusion will be checked then it will be cemented using type-I glass ionomer cement, Any excess cement will be removed.
zerconia crownOther
Occlusal reduction will be done by 1-1.5 mm using coarse football shaped diamond bur following the natural occlusal anatomy.
Interproximal contacts will be opened with a tapered fissure bur. The proximal space should be enough to permit the chosen crown to fit passively.
The molar will be trimmed down circumferentially 0.5-1.25 mm as needed with the use of tapered diamond burs.
•About 1 to 2 mm subgingival preparation will be done to achieve a feather-edge finish line.
Prepared tooth should be free from any blood or saliva. Try-in will be done using the pink crowns, to check the occlusion and Passive fit of the crown.
The zirconia crown will be luted with type I glass ionemer cement. Consistent firm finger pressure will be applied during cementation, Any excess cement will be removed, and proper occlusion will be verified
stainless steel crownOther
An appropriately sized preformed stainless-steel crown will be selected. Tooth preparation will involve using a tapered bur to reduce the occlusal surface by 1 to 1.5 mm, with interproximal reduction made on the mesial and distal sides. The selected crown size will be checked, and a trial fit will be conducted prior to cementation. Crimping pliers will be used, and the crown will be cemented with Type 1 glass ionomer cement.
Any excess cement will be removed, and proper occlusion will be verified

Study groups in NCT07156838
Study group	Role	What they receive
bioflex crown	Experimental	Not described Receives: Other: bioflex crown
zerconia crown	Experimental	Not described Receives: Other: zerconia crown
stainless steel crown	Active comparator	Not described Receives: Other: stainless steel crown

What is being measured

The primary outcome is the main question the study is designed to answer.

gingival health
Evaluated using the gingival index, with scores of 0 (no inflammation), 1 (mild inflammation), 2 (moderate inflammation), and 3 (severe inflammation).
Measured: follow up at 3,6 and 9 months

Secondary outcomes (6)

plaque accumulation
Measured using the plaque index was scored from 0 to 3 (0 = no plaque, 1=Soft debris covering not more than one third of the tooth surface, 2=Soft debris covering more than one third, but not more than two thirds, 3 =Soft debris covering more than two thirds of the tooth surface.
Measured: 3,6 and 9 months
crown retention
Assessed using the Modified United States Public Health Service Evaluation (USPHS) criteria, where "Alpha" = the crown is intact, "Bravo" = Crown is chipped (small but noticeable loss of material)but not enough to expose the underlying dentin/base, and "Charlie" = sufficient loss of crown substance to expose the underlying dentin/base or complete loss of the crown
Measured: 3,6 and 9 months
marginal integrity
Assessed using the Modified United States Public Health Service Evaluation (USPHS) criteria , where "Alpha" indicates that the Crown is completely adapted to the tooth. No visible gap. No explorer catch at the margins, "Bravo" indicates Explorer catch, There is no visible evidence of a gap into which the explorer could penetrate, "Charlie" indicates Explorer penetrates into a deep gap that exposes dentin
Measured: 3,6 and 9 months
color change
Assessed using the Modified United States Public Health Service Evaluation (USPHS) criteria where:
alpha =no change in color bravo= clinically acceptable, with staining that could be polished away charlie=clinically unacceptable, with heavy staining that could not be polished away
Measured: 3,6 and 9 months
parental satisfaction
The questionnaire for assessing parental satisfaction includes four main categories for rating the following parameters whether the child's oral health, appearance and masticatory function were improved after placement of the crowns. Criteria evaluated in the survey will include also the parent's perception of the color and retention of each crown.
Responses will be recorded on a five-point Likert scale, ranging from 1 (not at all satisfied) to 5 (very satisfied).
Measured: 3,6 and 9 months
child post-operative discomfort
Post-operative discomfort will be assessed Immediately after the dental procedure using a modified face pain scale, It consists of three schematic faces with different facial expressions for happy face (A) , indifferent face (B) and sad crying face (C) representing:
A= Satisfaction B=Indifference C= Dissatisfaction each parent or guardian will be contacted via phone call after 48 hours to gather information about any sensitivity \ pain reported by the child.
Measured: immediately post-operative and 48 hours post-operative

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

10 Feb 202517 Dec 2025

First posted5 Sep 2025
Study start10 Feb 2025
Primary completion17 Dec 2025
Study completion17 Dec 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Publications (6)Papers the sponsor has linked to this study.
Other trials for Badly Decayed Primary MolarsStudies of the same condition, open and under way.
More trials run by Alexandria 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: None (open label)
Enrolment: 45 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT07156838
Sponsor's protocol ID: 1003-11/2024
Status last verified: Aug 2025
First submitted: 27 Aug 2025
Last updated: 28 Oct 2026
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No: patient privacy

Publications

Taran PK, Kaya MS. A Comparison of Periodontal Health in Primary Molars Restored with Prefabricated Stainless Steel and Zirconia Crowns. Pediatr Dent. 2018 Sep 15;40(5):334-339.
PubMed 30355428
Clark L, Wells MH, Harris EF, Lou J. Comparison of Amount of Primary Tooth Reduction Required for Anterior and Posterior Zirconia and Stainless Steel Crowns. Pediatr Dent. 2016 Jan-Feb;38(1):42-6.
PubMed 26892214
Salman N, Khattab N, Gomaa Y, Elheeny A. Parental satisfaction regarding two types of commercial crowns for restoring pulpotomized primary molars. Egypt Dent J . 2021;67:2915-21.
Sai Sarath K, Murali G, Elangovan A, Kalaivanan D. Case series on personalized pediatric posterior Zirconia crowns: Case report. Int J Pedod Rehabil . 2022;7:46-50.
Mittal GK, Verma A, Pahuja H, Agarwal S, Tomar H. Esthetic crowns in pediatric dentistry: A review. Int J Contemporary Medical Res. 2016;3:1280-2.
Holsinger DM, Wells MH, Scarbecz M, Donaldson M. Clinical Evaluation and Parental Satisfaction with Pediatric Zirconia Anterior Crowns. Pediatr Dent. 2016;38(3):192-7.
PubMed 27306242

Study at a glance

From the registry record, last updated by the sponsor on 28 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Evaluation of Bioflex and Zirconia Crowns Versus Stainless Steel Crowns on Primary Molars: Randomized Controlled Clinical Trial
ClinicalTrials.gov ID: NCT07156838
Acronym / sponsor ID: 1003-11/2024
Conditions: Badly Decayed Primary Molars, Preformed Pediatric Posterior Crowns
Keywords: bioflex crown, zerconia crown, stainless steel crown, clinical success
Study type: Interventional
Recruitment status: Completed
Enrolment: 45 participants (actual)
Lead sponsor: Alexandria UniversityUniversity, hospital or other
Study start: 10 Feb 2025 (actual)
Primary completion: 17 Dec 2025 (actual)
Study completion: 17 Dec 2025 (actual)
First posted: 5 Sep 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 clinical effectiveness of bioflex crowns and zirconia crowns compared to stainless steel crowns when
restoring primary molars 45 participant who their ages range between 6 and 8 years participated in this study. The participants will be divided into three groups: group (A) for Bioflex crown (n=15), group (B) for Zirconia crown (n=15) and group ( C) for Stainless steel crown(n=15).

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 3

Arm	Type	Receives
bioflex crown	Experimental	Other: bioflex crown
zerconia crown	Experimental	Other: zerconia crown
stainless steel crown	Active comparator	Other: stainless steel crown

Who may qualify

Ages: 6 to 8 years
Sex: All
Healthy volunteers: Accepted
Age groups: Child

Key inclusion criteria (6 listed)

Children who are free from any systemic disease.
Cooperative children (positive/ definitely positive) according to Frankl's behavior rating scale.
Children with good to fair oral hygiene according to Loe and Silness plaque index.
Primary molars with deep carious lesion, that are indicated for pulpotomy and crown.
Primary molars having two-thirds of root structure left radiographically

Key exclusion criteria (4 listed)

Children with oral parafunctional habits.
Primary molars with bifurcation involvement
Presence of abscess or fistula related to the selected tooth
Primary molars with insufficient crown structure

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
bioflex crownA preformed bioflex crown of similar size will be selected. Tooth preparation will be done using a tapered diamond bur to reduce the occlusal surface, including the central groove, by 1-1.5 mm. The proximal surfaces will be prepared by approximately 0.5 mm to clear the contact area, bioflex crown fitting and proper occlusion will be checked then it will be cemented using type-I glass ionomer cement, Any excess cement will be removed.	Other	bioflex crown
zerconia crownOcclusal reduction will be done by 1-1.5 mm using coarse football shaped diamond bur following the natural occlusal anatomy. Interproximal contacts will be opened with a tapered fissure bur. The proximal space should be enough to permit the chosen crown to fit passively. The molar will be trimmed down circumferentially 0.5-1.25 mm as needed with the use of tapered diamond burs. •About 1 to 2 mm subgingival preparation will be done to achieve a feather-edge finish line. Prepared tooth should be free from any blood or saliva. Try-in will be done using the pink crowns, to check the occlusion and Passive fit of the crown. The zirconia crown will be luted with type I glass ionemer cement. Consistent firm finger pressure will be applied during cementation, Any excess cement will be removed, and proper occlusion will be verified	Other	zerconia crown
stainless steel crownAn appropriately sized preformed stainless-steel crown will be selected. Tooth preparation will involve using a tapered bur to reduce the occlusal surface by 1 to 1.5 mm, with interproximal reduction made on the mesial and distal sides. The selected crown size will be checked, and a trial fit will be conducted prior to cementation. Crimping pliers will be used, and the crown will be cemented with Type 1 glass ionomer cement. Any excess cement will be removed, and proper occlusion will be verified	Other	stainless steel crown

Primary outcome

gingival health
Time frame: follow up at 3,6 and 9 months
Evaluated using the gingival index, with scores of 0 (no inflammation), 1 (mild inflammation), 2 (moderate inflammation), and 3 (severe inflammation).

6 secondary outcomes

plaque accumulation
Time frame: 3,6 and 9 months
crown retention
Time frame: 3,6 and 9 months
marginal integrity
Time frame: 3,6 and 9 months
color change
Time frame: 3,6 and 9 months
parental satisfaction
Time frame: 3,6 and 9 months
child post-operative discomfort
Time frame: immediately post-operative and 48 hours post-operative

Results and safety

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 28 Oct 2026.
Background: PubMed 30355428Taran PK, Kaya MS. A Comparison of Periodontal Health in Primary Molars Restored with Prefabricated Stainless Steel and Zirconia Crowns. Pediatr Dent. 2018 Sep 15;40(5):334-339.
Background: PubMed 26892214Clark L, Wells MH, Harris EF, Lou J. Comparison of Amount of Primary Tooth Reduction Required for Anterior and Posterior Zirconia and Stainless Steel Crowns. Pediatr Dent. 2016 Jan-Feb;38(1):42-6.
BackgroundSalman N, Khattab N, Gomaa Y, Elheeny A. Parental satisfaction regarding two types of commercial crowns for restoring pulpotomized primary molars. Egypt Dent J . 2021;67:2915-21.
BackgroundSai Sarath K, Murali G, Elangovan A, Kalaivanan D. Case series on personalized pediatric posterior Zirconia crowns: Case report. Int J Pedod Rehabil . 2022;7:46-50.
BackgroundMittal GK, Verma A, Pahuja H, Agarwal S, Tomar H. Esthetic crowns in pediatric dentistry: A review. Int J Contemporary Medical Res. 2016;3:1280-2.
Background: PubMed 27306242Holsinger DM, Wells MH, Scarbecz M, Donaldson M. Clinical Evaluation and Parental Satisfaction with Pediatric Zirconia Anterior Crowns. Pediatr Dent. 2016;38(3):192-7.
Individual participant dataSharing planned: No. patient privacy

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.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

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 6 inclusion and 4 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: finished, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site 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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

gingival health (time frame: follow up at 3,6 and 9 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 NCT07156838, which also lists 6 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 28 Oct 2026.