Retention of Bioflx Crowns Compared to Zirconia Crowns on Primary Molars

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Carious Primary Molars
• Intervention / Treatment: Other: (Group A: Preformed Bioflx crown); Other: (Group B: Preformed Zirconia crown)

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 Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: noura jamal elnoor mohamed, bachelor of dental science; Phone Number: 00201148788374; Email: nourajamal997@gmail.com

Study Locations

• Egypt
  • Cairo, Egypt
    • Faculty of Dentistry, Cairo University.
  • Giza
    • Cairo, Giza, Egypt, 12613
      • Faculty of Dentistry, Cairo University.
      • Contact: noura jamal elnoor mohamed, B.DSc; Phone Number: 00201148788375; Email: nourajamal997@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:The inclusion criteria:

1. Children aged between 4 and 8 years with primary molar that needs to be covered by crown.
2. Children who can cooperate sufficiently for the duration of the procedure, as assessed by behavior management techniques.
3. Medically healthy children (ASA I or II according to the American Society of Anesthesiologists classification).
4. Children whose parent or guardian are willing to sign an informed consent.
5. Children whose parent or guardian are willing to comply with follow-up visits. -

Exclusion Criteria:

• The exclusion criteria

  1. Molars with severe structural loss that may compromise crown retention.
  2. Children with poor oral hygiene that may contribute to higher plaque levels and affect the clinical outcomes of the crown restorations.
  3. Children with history of allergies; Known allergies to dental local anesthesia or to the materials used in Bioflx crowns.
  4. Children with any systemic conditions or disabilities that may affect their ability to participate in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: (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	Other: (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,
Experimental: (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.	Other: (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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retention	Method of Measurement:Modified United States Public Health System criteria:Alpha: Intact Bravo:Chipped/loss of material Charlie: Complete loss of crown	follow-up:T (Time): 6months interval T0: 0 T1: 3month T2: 6month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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	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	T (Time): 6months interval T0: 0T1: 3month T2: 6month
Preparation time	Measure by :Stopwatch per minutes.	baseline

Collaborators and Investigators

• Sponsor: Cairo University
• Investigators: Study Director: Dr.manal ahmed elshiekh Prof, Ph.D, Cairo University

Publications and helpful links

General 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.
• Patil 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.

Study record dates

Study Major Dates

• Study Start (Estimated): June 30, 2025
• Primary Completion (Estimated): December 1, 2025
• Study Completion (Estimated): February 1, 2026

Study Registration Dates

• First Submitted: February 25, 2025
• First Submitted That Met QC Criteria: March 3, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 3, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: RR-BFC Vs ZR

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No