Luting Cements for Prefabricated Zirconia Crown Retention in Primary Anterior Teeth in Children

Comparison of Self-Adhesive Resin, Conventional Glass Ionomer, and Bioactive Resin-Modified Glass Ionomer Cements for Prefabricated Zirconia Crown Retention in Primary Anterior Teeth: A Randomized Controlled Trial

The goal of this clinical trial is to compare the long-term clinical performance of three different luting cements used to bond prefabricated zirconia crowns (PZCs) on primary front teeth in young children. The trial will determine whether any single cement offers superior retention, gum health, or marginal sealing compared to the others over a 3-year period.

Main Questions:

The study aims to answer the following:

Are conventional glass ionomer cement (GIC), bioactive resin-modified glass ionomer cement (BioCem™), and self-adhesive resin cement (SARC) equivalent in retaining prefabricated zirconia crowns on primary incisors over 36 months? Do these cements differ in their effect on gingival health, plaque accumulation, or marginal discoloration around the cemented crown?

Comparison:

Researchers will compare three parallel groups of children whose primary incisors are restored with identical prefabricated zirconia crowns but cemented with one of the three different luting cements.

Participants will: Receive a clinical and radiographic dental examination at screening. Undergo placement of one or more prefabricated zirconia crowns on primary anterior teeth using their randomly assigned cement. Return to the clinic for blinded follow-up evaluations at 12, 24, and 36 months for assessment of crown retention, gingival health, plaque, and marginal staining.

Study Overview

• Status: Not yet recruiting
• Conditions: Dental Caries; Tooth Injuries; Primary Tooth Restoration
• Intervention / Treatment: Procedure: Cementation with Fuji IX GP Extra Glass Ionomer Cement; Procedure: Cementation with BioCem™ Universal BioActive Cement; Procedure: Cementation with RelyX™ Universal Resin Cement

Detailed Description

This prospective, parallel-group, three-arm, randomized controlled trial evaluates the long-term clinical performance of three commercially available luting cements when used to bond prefabricated zirconia crowns (PZCs) on primary anterior teeth in pediatric patients. Although PZCs are increasingly preferred over stainless steel crowns for anterior restorations due to their superior esthetics and biocompatibility, their retention relies entirely on the luting cement because of their passive fit and conservative preparation design. Comparative clinical evidence on cement performance in this specific anatomical and functional context remains limited.

Trial Design:

The trial is conducted at the Pediatric Dental Clinic of Qassim University, Riyadh, Saudi Arabia. Eligible children aged 2 to 7 years requiring full-coverage restoration of one or more primary incisors are randomized in a 1:1:1 ratio to one of three cement groups using a computer-generated randomization sequence. Allocation labels are reshuffled after each assignment to preserve equal group sizes. An independent outcome assessor is blinded to group allocation throughout the trial, and standardized cheek retractors are used to mask cement margins during evaluations. Operators cannot be blinded due to material-specific application protocols.

Intervention Protocols:

Tooth preparation follows standardized anterior-specific minimal reduction principles (1.0-1.5 mm incisal, 0.5-0.8 mm uniform labial, feather-edge proximal margins) under rubber dam isolation. NuSmile® prefabricated zirconia crowns are used for all participants. Cement application follows manufacturer instructions for each group:

Group 1 (GIC): Fuji IX GP Extra (GC America) - tooth conditioned with 20% polyacrylic acid for 20 seconds, rinsed, gently air-dried; cement hand-mixed, loaded into crown, seated under finger pressure for 3 minutes.

Group 2 (BioCem™): BioCem™ Universal BioActive Cement (NuSmile®) - tooth cleaned with pumice and water, rinsed, dried; cement auto-mixed into crown, seated, briefly light-cured (2-3 s) for excess removal, then fully light-cured 20 s per surface.

Group 3 (SARC): RelyX™ Universal Resin Cement (3M) - tooth cleaned with pumice and water, rinsed, dried; cement loaded, crown seated, tack-cured 2-3 s, excess removed, full light-curing 20 s per surface.

All crowns are placed by a single calibrated pediatric dentist. Post-cementation periapical radiographs verify marginal integrity. Parents receive standardized oral hygiene instructions and a 7-day course of 0.12% chlorhexidine mouthwash.

Follow-Up and Safety:

Clinical evaluations occur at baseline, 12, 24, and 36 months. Retention is assessed by visual/tactile examination with a sharp explorer and LED transillumination (DEXIS CariVu®). Failed crowns are recemented and excluded from subsequent analyses. Adverse events including soft-tissue irritation, crown fracture, debonding, and aspiration risk are continuously recorded.

Statistical Methodology:

Sample size was calculated using G*Power 3.1.9.7 assuming a medium effect size (f = 0.25) for ANOVA, 90% power, and α = 0.05, yielding 28 participants per group; this was inflated to 40 per group (total 120) to accommodate an anticipated 30% attrition over 36 months. The primary retention outcome will be analyzed by Kaplan-Meier survival analysis with between-group comparison using the log-rank test, supplemented by Fisher's exact test for proportional retention and Cox proportional hazards regression for hazard ratios. Gingival Index and Plaque Index will be compared between groups by one-way ANOVA and within groups by repeated-measures ANOVA. Margin discoloration distribution will be compared by chi-square (with Cramér's V as effect size) and within-group transitions by McNemar's test. Significance is set at p < 0.05. Analyses will follow an intention-to-treat principle, with per-protocol sensitivity analyses.

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: MURAD ALRASHIDI, BDS, MSC; Phone Number: +966 55 302 2773; Email: MU.ALRASHIDI@qu.edu.sa

Study Locations

• Saudi Arabia
  • Al-Qassim Region
    • Buraidah, Al-Qassim Region, Saudi Arabia, 52571
      • Qassim University
      • Contact: MURAD ALRASHIDI; Phone Number: +966 55 302 2773; Email: MU.ALRASHIDI@qu.edu.sa

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Healthy children aged 2 to 7 years
2. One or more primary maxillary or mandibular incisors requiring full-coverage restoration due to caries or trauma
3. Adequate remaining tooth structure following preparation, defined as greater than 50% of the clinical crown
4. Parent or legal guardian able and willing to provide written informed consent and to commit to the 36-month follow-up schedule

Exclusion Criteria:

1. Active periodontal disease at the index tooth, defined as a Löe Gingival Index score of 2 or higher
2. Parafunctional habits such as bruxism, severe thumb-sucking, or tongue-thrust documented at screening
3. Known allergy or hypersensitivity to zirconia, resin, glass ionomer, or any component of the assigned cement
4. Inconsistent oral hygiene, defined as less than twice-daily toothbrushing per parental report
5. Systemic disease affecting bone metabolism, tooth development, or wound healing
6. Current participation in another interventional dental clinical trial

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Glass Ionomer Cement (GIC) Group; Glass Ionomer Cement (GIC) Group: Participants receive a NuSmile® prefabricated zirconia crown cemented with conventional glass ionomer cement (Fuji IX GP Extra, GC America) following a standardized polyacrylic-acid-conditioning protocol.	Procedure: Cementation with Fuji IX GP Extra Glass Ionomer Cement; Cementation with Fuji IX GP Extra Glass Ionomer Cement Hand-mixed conventional glass ionomer luting cement applied per manufacturer protocol; crown seated under finger pressure for 3 minutes; excess removed after initial set.
Experimental: Bioactive Resin-Modified Glass Ionomer Cement (BioCem™) Group; Bioactive Resin-Modified Glass Ionomer Cement (BioCem™) Group: Participants receive an identical NuSmile® prefabricated zirconia crown cemented with BioCem™ Universal BioActive Cement (NuSmile®, Houston, TX, USA).	Procedure: Cementation with BioCem™ Universal BioActive Cement; Cementation with BioCem™ Universal BioActive Cement Auto-mixed bioactive resin-modified luting cement applied per manufacturer protocol; brief tack-cure to facilitate excess removal followed by full light-curing for 20 seconds per surface.
Experimental: Self-Adhesive Resin Cement (SARC) Group; Self-Adhesive Resin Cement (SARC) Group: Participants receive an identical NuSmile® prefabricated zirconia crown cemented with RelyX™ Universal Resin Cement (3M).	Procedure: Cementation with RelyX™ Universal Resin Cement; Cementation with RelyX™ Universal Resin Cement Self-adhesive dual-cure resin luting cement applied per manufacturer protocol; tack-cured for 2-3 seconds for excess removal, followed by full light-curing for 20 seconds per surface.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Crown Retention (Survival)	The primary outcome is the cumulative retention of prefabricated zirconia crowns over a 36-month follow-up period. Retention is assessed by a single blinded examiner at each scheduled visit using two complementary methods: (a) visual/tactile inspection with a sharp dental explorer applied circumferentially along the crown margin to detect dislodgement, mobility, or marginal gap; and (b) LED transillumination using the DEXIS CariVu® system to detect cracks, debonding, or marginal microleakage. A crown is classified as "failed" (debonded) if any complete loss of cement seal, dislodgement, or detectable marginal gap is observed. Retention is reported as the proportion of crowns surviving at each time point and as the time-to-failure for survival analysis. Higher retention proportions and longer survival times indicate better clinical performance.	Baseline, 12, 24, and 36 months post-cementation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plaque Accumulation Measured by the Silness & Löe Plaque Index (1964)	Plaque accumulation at the gingival margin of each cemented crown is assessed using the Silness & Löe Plaque Index. The same four sites per tooth (mesial, distal, buccal, lingual) are scored by a blinded examiner on a 4-point ordinal scale: 0 = no plaque; 1 = a film of plaque adhering to the free gingival margin, recognizable only by running a probe across the surface; 2 = moderate accumulation of soft deposits visible to the naked eye; 3 = abundance of soft matter. A mean PI score is calculated per tooth and per participant; the participant-level mean ranges from a minimum of 0 to a maximum of 3, with higher scores indicating greater plaque accumulation.	Baseline, 12, 24, and 36 months post-cementation
Gingival Health Measured by the Löe Gingival Index (1967)	Gingival inflammation around each cemented crown is assessed at baseline and at every follow-up visit using the Löe Gingival Index (1967). A single blinded examiner scores four gingival sites per tooth (mesial, distal, buccal, and lingual) on a 4-point ordinal scale: 0 = no clinical inflammation (normal gingiva); 1 = mild inflammation (slight color change, slight edema, no bleeding on probing); 2 = moderate inflammation (redness, edema, glazing, bleeding on probing); 3 = severe inflammation (marked redness and edema, ulceration, tendency to spontaneous bleeding). A mean GI score is calculated per tooth and per participant; the participant-level mean therefore ranges from a minimum of 0 to a maximum of 3, with higher scores indicating worse gingival health.	Baseline, 12, 24, and 36 months post-cementation
Marginal Discoloration Measured by the Modified United States Public Health Service (USPHS) Criteria	Discoloration at the crown-tooth interface is evaluated under standardized LED operatory lighting (1,000-1,400 lux) without magnification using the modified USPHS criteria, supplemented by high-resolution intraoral photography with cross-polarized filters. Each crown is assigned one of four ordinal ratings: Alpha (A) = no visible discoloration (best outcome); Bravo (B) = slight discoloration confined to the margin, not penetrating internally; Charlie (C) = obvious discoloration penetrating along the margin; Delta (D) = severe discoloration with secondary caries or restoration failure (worst outcome). The outcome is reported as the proportion of crowns in each category at each time point, with a higher proportion of Alpha ratings indicating better marginal integrity.	Baseline (immediately post-cementation), 12, 24, and 36 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence and Severity of Adverse Events	The frequency, type, and severity of all adverse events occurring during the 36-month follow-up will be recorded for each arm. Events of interest include crown debonding, crown fracture, soft-tissue irritation or ulceration adjacent to the crown margin, allergic reaction to cement components, secondary caries, and pulpal complications. Severity will be classified using a three-tier framework adapted from the Common Terminology Criteria for Adverse Events (CTCAE) approach: Mild (Grade 1) - no intervention required; Moderate (Grade 2) - non-urgent intervention required (e.g., recementation at a scheduled visit); Severe (Grade 3) - urgent intervention, crown replacement, or treatment of secondary pathology required. The primary safety endpoint is the incidence rate (events per participant per year of follow-up) in each arm.	Continuously, from cementation through 36 months

Collaborators and Investigators

• Sponsor: Murad Alrashidi
• Investigators: Principal Investigator: MURAD ALRASHIDI, BDS, MSC, Qassim University

Publications and helpful links

General Publications

• Leuciuc FV, Petrariu I, Pricop G, Rohozneanu DM, Popovici IM. Toward an Anthropometric Pattern in Elite Male Handball. Int J Environ Res Public Health. 2022 Feb 28;19(5):2839. doi: 10.3390/ijerph19052839.
• Wu M, Liu X, Li Z, Huang X, Guo H, Guo X, Yang X, Li B, Xuan K, Jin Y. SHED aggregate exosomes shuttled miR-26a promote angiogenesis in pulp regeneration via TGF-beta/SMAD2/3 signalling. Cell Prolif. 2021 Jul;54(7):e13074. doi: 10.1111/cpr.13074. Epub 2021 Jun 7.

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): June 1, 2029
• Study Completion (Estimated): July 1, 2029

Study Registration Dates

• First Submitted: May 21, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 28, 2026

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Glass Ionomer Cement; Luting Cement; Prefabricated Zirconia Crown; Bioactive Cement; Self-Adhesive Resin Cement; Crown Retention
• Additional Relevant MeSH Terms: Stomatognathic Diseases; Wounds and Injuries; Tooth Diseases; Tooth Demineralization; Dental Caries; Tooth Injuries; Investigative Techniques; Dentistry; Dental Bonding; Cementation
• Other Study ID Numbers: 26-19-6

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The investigators will share de-identified individual participant data underlying the results reported in the final publication. Shared data may include retention status at each time point, time-to-failure, Gingival Index and Plaque Index scores, USPHS marginal discoloration ratings, and adverse event records. The study protocol and statistical analysis plan will also be made available.
• IPD Sharing Time Frame: Data will be available beginning 6 months and ending 36 months following article publication.
• IPD Sharing Access Criteria: Data will be shared with researchers who provide a methodologically sound proposal and whose intended use has been approved by an independent review committee. Proposals should be directed to the primary investigator. To gain access, requestors must sign a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No