An interventional study of NAC and APA in Missing Incisors, Zirconia Surface Pretreatment and Children, sponsored by University of Ljubljana, Faculty of Medicine. Recruiting at 1 site in Slovenia. Per ClinicalTrials.gov, last updated 2026-06-23.
Sponsored by University of Ljubljana, Faculty of Medicine · Not applicable, Interventional, and Treatment
The purpose of this study is to evaluate the clinical outcome of resin-bonded fixed dental prostheses (RBFDPs) pretreated with nanostructured alumina coating (NAC).
The study adopts a prospective, randomized, controlled, double-blind design contrasting the use of NAC to air-borne particle abrasion (APA) (control) as a surface pretreatment method of zirconia RBFDPs used for replacing missing central or lateral incisors. The primary outcome evaluated is the retention/survival of the zirconia RBFDPs pretreated with APA and NAC.
Zirconia resin-bonded fixed dental prostheses (RBFDPs) have been regarded as a promising minimally invasive alternative for the replacement of missing central and lateral incisors, offering several advantages to orthodontic space closure or tooth replacement with implant-supported restorations. Debonding of the zirconia RBFDPs represents the main technical complication since clinically established airborne particle abrasion (APA) of an inert zirconia surface does not always provide sufficient resin-bond strength. Further, APA can also impair the mechanical properties of zirconia restoration affecting its long-term success. Nano-structured alumina coating (NAC) presents an alternative non-invasive zirconia surface pretreatment. The aim of this randomized controlled clinical trial is to study the effect of NAC coated bonding surface of zirconia RBFDPs affecting its debonding and clinical survival rate.
The study adopts a prospective, randomized, controlled, double-blind design contrasting the use of NAC to air-borne particle abrasion (APA) as a surface pretreatment method of zirconia RBFDPs. Healthy patients in need of a missing central or lateral incisor replacement are screened and rated to be eligible by two calibrated dentists. RBFDPs are randomly allocated into two groups and inserted by the same operator. The first group, where the bonding surface is pretreated with APA serves a control group. In the second group the restorations are pretreated with NAC. The participants and the operator are blinded to the group assignment in a double-blinded trial design. The primary outcome evaluated is the retention/survival of the RBFDP. Non-parametric tests and Kaplan-Meyer analysis will be used to determine differences between both study groups.
University of Ljubljana, Faculty of Medicine is the lead sponsor of 17 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
1. Patients with missing central or lateral incisor
Exclusion Criteria:
Air-borne particle abrasion of zirconia RBFDPs prior to bonding
Other: APA
Pretreatment of zirconia RBFDP with nanostructured alumina coating after milling of RBFDP's framework
Other: NAC
Pretreatment of zirconia RBFDP with nanostructured alumina coating after milling of RBFDP's framework
Air-borne particle abrasion of zirconia RBFDPs prior to bonding
Survival rate of zirconia RBFDPs
Survival rate is defined by debonding or restoration loss
Time frame: From baseline through study completion, an average of 1 year
Porcelain chipping
Porcelain chipping
Time frame: From baseline through study completion, an average of 1 year
Zirconia framework fracture
Zirconia framework fracture
Time frame: From baseline through study completion, an average of 1 year
Gingivitis
Visual and tactile inspection of gingiva
Time frame: From baseline through study completion, an average of 1 year
Parodontitis
Gingival sulcus depth measurement
Time frame: From baseline through study completion, an average of 1 year
Marginal leakage
Discoloration of a restoration margin
Time frame: From baseline through study completion, an average of 1 year
Secondary caries
Caries between the tooth and restoration margin
Time frame: From baseline through study completion, an average of 1 year
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Ljubljana, Faculty of Medicine