Bacterial Colonization, Gingival Health, and Surface Roughness of Three Crown Types in Children's Teeth
Carious Lesion · Ready-made Crowns
What this study involves
The registry does not currently label this study as recruiting. Ask about its status before planning a screening visit.
- Study type
- Interventional
- Phase
- Not applicable
- Age range
- 4 years - 8 years
- Sex eligible
- All sexes
- Healthy volunteers
- Not accepted
- Participants
- 75 Estimated
These are starting points, not an eligibility decision. The research team must review the full requirements.
About the research
Following the restoration of primary molars with stainless steel and bioflex crowns, an evaluation of the current state of oral hygiene in relation to the amount of microorganisms and gingival health in the oral cavity will be carried out.
Who may be able to participate?
The list below is the sponsor’s full registry wording. It can include conditions, prior treatment, test results and other requirements. A match in search does not mean you qualify.
Inclusion Criteria:
- Participants aged between 4 and 8 years.
- Pulp therapy treated primary molars on the contralateral side, requiring a full coverage restoration (split-mouth technique).
- No history of any antibiotic consumption 2 weeks before the procedure.
- No history of fluoride application 2 weeks before the procedure.
Exclusion Criteria:
- Special children with physical disabilities or emotional disturbances.
- Children are diagnosed with systemic diseases.
- Grossly destructed teeth with non-restorable crown structure.
- Primary teeth with shedding or pathological tooth mobility.
Treatment, groups and participation
The registry may describe treatments and study duration without a complete visit calendar. Ask the study team for the exact schedule, procedures, risks, costs and alternatives. Keep your usual care plan unless your treating clinician tells you otherwise.
- Assignment
- Random assignment
- Masking
- Single masked
Group S
Carious primary molars restored with a preformed stainless steel crown (conventional full-coverage restoration) after pulpotomy. Surface roughness, Streptococcus mutans colonization, and gingival health (gingival and plaque indices) are assessed at baseline (before crown placement) and at 1 and 6 months.
Other: Group S
Group B
Carious primary molars restored with a preformed Bioflx hybrid resin-polymer crown after pulpotomy. The same outcomes (surface roughness, Streptococcus mutans colonization, gingival and plaque indices) are assessed at baseline and at 1 and 6 months.
Other: Bioflx crown
Group Z
Carious primary molars restored with a preformed zirconia crown (smooth-surface benchmark) after pulpotomy. The same outcomes are assessed at baseline and at 1 and 6 months.
Other: Group Z
Bioflx crown OTHER
Preformed Bioflx crown, a metal-free, tooth-coloured hybrid resin-polymer crown combining properties of stainless steel and zirconia; the material under investigation.
Group Z OTHER
Preformed tooth-coloured zirconia crown; a highly polished, smooth full-coverage restoration serving as the smooth-surface comparator.
Group S OTHER
Preformed Bioflx crown, a metal-free, tooth-coloured hybrid resin-polymer crown combining properties of stainless steel and zirconia; the material under investigation.
What researchers are measuring
Outcome measures describe what is being studied. They are not proof that a treatment works.
Primary measures
Streptococcus mutans colonization on stainless steel, Bioflx, and zirconia crowns Description
Time frame: Baseline (before crown placement), 1 month, and 6 months
Streptococcus mutans colonization on the crown surface will be assessed by collecting plaque samples with sterile cotton swabs from the crown surface, the surrounding gingival crevice, and the mucosa (and from the natural tooth surface at baseline, before crown placement). Samples are inoculated onto mitis-salivarius-bacitracin agar (MSBA), a selective medium for S. mutans, incubated at 37°C for 48 hours under microaerophilic conditions; colonies are counted and expressed as colony-forming units per millilitre (CFU/mL).
Secondary measures
Gingival Index (GI)
Time frame: baseline, 1, 6 months.
Löe \& Silness; scored 0-3 on four surfaces of the crowned tooth.
Plaque Index (PI)
Time frame: baseline, 1, 6 months.
Silness \& Löe scored 0-3 on four surfaces.
Review the complete result tables and limitations in the official record.
Open official results ↗Research locations (2)
The overall study status and a local site’s status can differ. Confirm that location’s availability before traveling.
2 locations
Al-Azhar UniversityCairo, Nasr City, EgyptStatus unknown
Faculty of Dental Medicine at Al-Azhar University.Cairo, Nasr City, EgyptStatus unknown
Study team and timeline
- Lead sponsor
- Al-Azhar University
- Study start
- 2027-07 Estimated
- Primary completion
- Nov 1, 2027 Estimated
- Study completion
- Dec 1, 2027 Estimated
- First posted
- Jan 10, 2025 Actual
- Last updated
- Nov 10, 2026 Actual
Official study contacts
Official study title
Evaluation of Oral Hygiene Status in Correlation With Microbial Load in the Oral Cavity Following Restorations of Primary Molars Using Stainless Steel and Bioflex Crowns (Clinical Randomized Trial)
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Source: ClinicalTrials.gov API v2. Information is submitted by sponsors and investigators. NLM does not approve the safety or science of all listed studies. Registry disclaimer.
Retrieved: Nov 11, 2026 · Last registry update: Nov 10, 2026