Movement of Dental Implants During Osseointegration

Overview

Prospective multicenter observational study assessing whether dental implants undergo three-dimensional positional change between placement (T0) and pre-loading after osseointegration (T1). Two intraoral scans (STL) will be superimposed to quantify linear (mm) and angular (degrees) displacement. Clinical variables include insertion torque, primary and secondary ISQ, anatomical site, placement timing, operator-perceived bone density (Lekholm \& Zarb), bruxism, and night guard use. The primary endpoint is the 3D displacement at \~3-4 months. Multivariable analyses will explore associated factors.

This is a prospective multicenter observational study designed to evaluate whether dental implants undergo measurable three-dimensional positional changes during the osseointegration period. The study will be conducted in three private dental clinics in Spain, each led by an experienced implantologist. Consecutive adult patients indicated for a single implant-supported restoration will be enrolled after providing written informed consent. Immediately after implant placement (T0), a reference intraoral scan (STL format) will be obtained using a validated scanner. A second intraoral scan will be performed after approximately 3 to 4 months, prior to prosthetic loading (T1). The two STL datasets will be superimposed using certified metrology software to calculate both linear (mm) and angular (degrees) displacement of the implant position relative to stable reference structures. The software alignment protocol ensures a reproducible and rigid registration of both scans. Clinical and procedural variables collected at surgery include insertion torque value (ITV), primary implant stability (ISQ1), implant site (maxilla or mandible; anterior, premolar, or molar region), timing of placement (immediate or delayed), and operator-perceived bone density according to the Lekholm and Zarb classification. At the pre-loading visit (T1), secondary stability (ISQ2) will be recorded together with information on bruxism and the use of night guards. The primary outcome is the 3D positional change (linear and angular) of the implant between T0 and T1. Secondary outcomes include the evolution of implant stability (ISQ2-ISQ1), correlations between displacement and insertion torque, and the influence of anatomical and patient-related variables (site, bone quality, bruxism, and loading protocol) on implant micromotion. All data will be anonymized and analyzed at the implant level. Descriptive statistics will summarize means, standard deviations, and confidence intervals. Paired comparisons will be used to test within-subject changes, and multivariable linear regression models will explore predictors of displacement. Statistical significance will be set at p \< 0.05. The results of this study are expected to contribute to understanding whether clinically relevant implant micromovement occurs during osseointegration and to identify factors influencing this phenomenon, potentially guiding decisions on early loading and implant design optimization.