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Completed

NCT Number: NCT07456995

Evaluation of Mandibular Posterior Zirconia Crowns With Different Ti-Base Surface Treatments.

This clinical trial evaluates how different surface treatments on a metal base (Ti-Base) affect the success of dental crowns on implants. Patients receiving a zirconia crown for a missing lower back tooth are divided into three groups: one group receives no special treatment on the metal base, one group receives a silica coating, and the third receives both a silica coating and a chemical primer. The study monitors these crowns for one year to see which treatment best prevents the crown from coming loose or breaking, while also checking the health of the surrounding gums.

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Key information

Conditions

Jaw, Edentulous, Partially Dental Implant Jaw Diseases Jaw, Edentulous Molar Teeth Mouth Diseases Mouth, Edentulous Musculoskeletal Diseases Periodontal Diseases Stomatognathic Diseases Tooth Diseases Tooth Loss

Age range

18 year–55 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

MSA University, Faculty of Dentistry

Giza, Giza Governorate, 14512, Egypt

About this study

This is a three-arm, parallel-group, superiority randomized controlled trial. The research question addresses the impact of silica coating (CoJet Sand) and primer (Z-Prime Plus) on the survival of mandibular posterior screw-retained zirconia crowns.+3The primary intervention involves treating the titanium base (Ti-Base) abutment surface using 30-mm $SiO_2-Al_2O_3$ particles at 2.0 bar pressure. The three groups are:Group I (Control): No surface treatment.Group II: Tribochemical silica coating alone.Group III: Tribochemical silica coating followed by Z-Prime Plus application.Survival is evaluated using modified United States Public Health Service (USPHS) criteria at baseline, 6 months, and 12 months. Biological health is assessed via the modified plaque index (mPI) and modified Sulcus Bleeding Index (mSBI).

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Age 18 - 55 years
  • Missing mandibular first molar with opposing natural teeth
  • Good oral hygiene and general health (ASA I or II)
  • Smoking ≤ 10 cigarettes/day

Exclusion criteria

  • Poor oral hygiene
  • Severe wear facets, clenching, or bruxism
  • Heavy smokers (>10 cigarettes/day)

Treatment and study plan

Tribochemical silica coating.

Device

Surface treatment of titanium base implant abutment using 30 um SiO2 - Al2O3 particles at 2.0 bar pressure.

Other names: CoJet Sand.

Tribochemical silica coating and Z-Prime Plus.

Device

Surface treatment of titanium base implant abutment using 30 um SiO2 - Al2O3 particles at 2.0 bar pressure, followed by the application of Z-Prime Plus primer.

Other names: CoJet Sand and Z-Prime Plus.

Primary outcomes

  1. Survival of screw-retained zirconia crown restorations.

    Time frame: Baseline (1 week post-cementation), 6 months, and 12 months.

    Evaluation of the restoration using modified United States Public Health Service (USPHS) criteria, specifically assessing fracture behavior, decementation, anatomical form, and marginal adaptation.

Secondary outcomes

  1. Modified Plaque Index (mPI)

    Time frame: 12 months.

    Evaluation of peri-implant health using the modified Plaque Index, scored from 0 to 3.

  2. Modified Sulcus Bleeding Index (mSBI)

    Time frame: 12 months

    Evaluation of peri-implant health using the modified Sulcus Bleeding Index, scored from 0 to 3.

Sponsors and collaborators

Lead sponsor

October University for Modern Sciences and Arts

Other

Registry information

Official study title

Clinical Evaluation of Mandibular Posterior Screw-retained Zirconia Crown With Various Ti-Base Abutment Surface Treatments: Randomized Controlled Clinical Trial

Acronym: RCT

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Mar 9, 2026
Registry last updated
Mar 9, 2026

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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