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NCT Number: NCT06890949

Occlusal Wear Of Bioflx Crowns Compared To Zirconia Crowns On Primary Molars

The goal of this clinical trial is to evaluate the occlusal wear 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 occlusal wear 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 retention,gingival health, preparation time, as well as child and parental satisfaction.

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Key information

Age range

4 year–8 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Faculty of dentistry cairo university

Cairo ,Giza, Egypt, 12613

Location contact

Eithar M Abdelrahman, BDS

PRINCIPAL_INVESTIGATOR

Faculty of dentistry cairo university

CONTACT

[email protected]

0020223642705

About this study

Occlusal wear is a critical factor in determining the longevity and functional efficiency of dental restorations, especially in pediatric patients. Primary molars undergo significant masticatory forces, which can lead to material wear and affect the restoration's durability. Bioflex (a relatively new material) and zirconia crowns are commonly used for full-coverage restorations in primary molars, yet there is limited research comparing their occlusal wear characteristics. Understanding how these materials perform under occlusal forces can guide clinicians in selecting the most suitable material for pediatric dental restorations Dental caries in primary molars represent a significant issue within pediatric dentistry. In cases where traditional fillings prove insufficient, full coronal coverage becomes necessary. Stainless steel crowns (SSCs) have long been the standard due to their durability and cost-effectiveness, but their metallic appearance has led to increased interest in aesthetic alternatives like zirconia and Bioflx crowns.

Zirconia offers improved aesthetics, biocompatibility, and mechanical strength, though its long-term clinical performance remains underexplored. While zirconia crowns provide durability and superior aesthetics, they require significant tooth preparation, which may compromise tooth structure. Bioflx crowns, a newer option, combine the benefits of stainless steel and zirconia with more flexibility and less tooth reduction. However, comparative studies on their clinical efficacy, occlusal wear, and patient satisfaction are still needed.

Zirconia offers improved biocompatibility, mechanical strength, and enhanced esthetics, but limited comparative data exists regarding its clinical performance.

The growing awareness among parents regarding the importance of maintaining primary teeth until their natural shedding necessitates a thorough evaluation of the durability, wear resistance, retention, gingival response, and overall clinical efficacy of these crown materials. Zirconia crowns have been the preferred choice for aesthetic restorations due to their natural appearance and durability. However, their requirement for excessive tooth preparation poses challenges in pediatric patients.

Bioflx crowns, made from a biocompatible hybrid resin polymer, offer a flexible fit with minimal tooth reduction while maintaining aesthetic appeal. A comprehensive comparison of occlusal wear between these two materials is crucial for assisting clinicians in selecting the most suitable restorative solution for primary molars. This research seeks to offer evidence-based guidance by evaluating the long-term clinical performance of Bioflx crowns in relation to zirconia crowns.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Children aged between 4 and 8 years with primary molar that needs to be covered by crown.
  • 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. -
  • Frankl's positive and definitely positive patient

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.

Treatment and study plan

(Group A: Preformed Bioflx Crown)

Other

Crown Selection & Tooth Preparation

Measure the mesiodistal width using calipers to select an appropriately sized crown.

If a mesial or distal wall is missing, use the contralateral tooth for size selection.

Choose the crown that closely matches the measured mesiodistal width. Select the smallest crown that preserves proximal contacts using a trial-and-error approach.

if crimping is necessary use Howe's pliers.

Tooth Preparation Perform 1-1.5 mm occlusal reduction using a tapered diamond bur. Reduce proximal areas by approximately 0.5 mm to clear the contact area.

Crown Placement & Cementation Ensure a snug fit of the selected crown. Apply a thin layer of glass ionomer cement inside the crown. Seat the crown firmly using finger pressure. Have the child bite down gently to ensure proper seating.

Final Adjustments & Cleanup Remove excess cement with floss or an explorer. Verify the crown's fit, occlusion, and stability.

(Group B: Preformed Zirconia crown)

Other

Crown Selection

Measure the mesiodistal width using calipers to select the appropriate crown. If a mesial or distal wall is missing, use the contralateral tooth for size selection.

Choose the crown that closely matches the measured width. Select the smallest crown that preserves proximal contacts.

Tooth Preparation

Reduce the occlusal surface by 1.5-2 mm using a tapered diamond bur. Reduce interproximal areas by 1-1.5 mm, ensuring a feather-edge finish. Perform a 1-2 mm subgingival preparation using a tapered fissure bur.

Crown Placement & Passive Fit Check

Place the selected crown and check for passive fit.

Cementation of the Crown

Apply a thin layer of glass ionomer cement inside the crown. Seat the crown with passive finger pressure. Have the child bite down gently to ensure proper seating.

Final Adjustments & Cleanup

Remove excess cement using floss or an explorer. Verify fit, occlusion, and stability

Primary outcomes

  1. Occlusal wear of crown

    Time frame: T (Time): 12months interval T0: 0 T1: 3 month T2: 6month T3: 12 month]

    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 exposure

Secondary outcomes

  1. Retention

    Time frame: [Time Frame: follow-up:T (Time): 12months interval T0: 0 T1: 3month T2: 6month T3 : 12 month]

    Measure by :Modified United States Public Health System criteria:Alpha: Intact Bravo:Chipped/loss of material Charlie: Complete loss of crown

  2. Gingival Health

    Time frame: T (Time): 12 months interval T0: 0 T1: 3month T2: 6month T3 : 12 month]

    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
  3. preparation time

    Time frame: [Time Frame: baseline]

    Measure by : Stopwatch per minutes.

  4. child and parental satisfaction

    Time frame: [Time Frame: T (Time): 12months interval T0: 0 T1: 3 month T2: 6month T3: 12 month]

    Measure by: 5-Point likert's scale units of measurement

    • very happy
    • happy
    • neither
    • unhappy
    • very unhappy / Questionnaire:Ordinary or N/ A existing validated tool

Study contacts

Contact information is provided by the study sponsor or research team.

Eithar musa Abdelrahman Hussion, Bachelor of dental science

CONTACT

[email protected]

00201098801323

Sponsors and collaborators

Lead sponsor

Cairo University

Other

Registry information

Official study title

Evaluation Of Occlusal Wear Of Bioflx Crowns Compared To Zirconia Crowns On Primary Molars

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Mar 24, 2025
Registry last updated
Mar 24, 2025

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.

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