This study is a long-term clinical follow-up of a previously conducted randomized trial comparing different levels of surgical guidance in dental implant placement. The follow-up phase aims to evaluate peri-implant clinical and radiographic outcomes over an extended observation period of up to 67 months. Clinical parameters and marginal bone level changes are assessed to determine whether the accuracy benefits observed at implant placement translate into favorable long-term biological outcomes.

The original clinical trial was designed to compare the accuracy of freehand and guided dental implant placement using different levels of surgical navigation. A total of 101 partially edentulous volunteers were enrolled and randomly assigned to one of four surgical protocols: freehand implantation, pilot-guided implantation, partially guided implantation, or fully guided implantation. Implant placement accuracy was evaluated by comparing the digitally planned implant positions with the actual postoperative implant positions using three-dimensional computerized analysis.

The present investigation represents an extended follow-up of this cohort, conducted to assess the long-term clinical performance of the placed implants. Follow-up evaluations began in February 2019 and continued until September 2024, resulting in a total observation period of up to 67 months. The extended duration exceeded the originally planned follow-up due to logistical interruptions related to the COVID-19 pandemic.

Clinical follow-up focused on peri-implant tissue health and marginal bone stability. Peri-implant probing depth was recorded as a clinical indicator of soft tissue conditions around the implants after delivery of the definitive prosthetic restorations. Measurements were performed at standardized sites around each implant, and mean probing depth values were calculated for longitudinal analysis.

Radiographic follow-up was performed using standardized bitewing radiographs to assess marginal bone levels. Marginal bone level was defined as the vertical distance between the implant platform and the alveolar crest, measured both mesially and distally. Because radiographic projection angles could not be fully standardized across all visits, individual calibration was performed for each implant using the known implant neck diameter provided by the manufacturer. This allowed reliable two-dimensional measurements despite variations in radiographic geometry.

The primary objective of this follow-up study is to describe long-term peri-implant clinical and radiographic outcomes following implant placement performed with varying levels of surgical guidance. Secondary objectives include assessing the stability of marginal bone levels over time and identifying potential differences between surgical protocols in long-term biological performance.

Inclusion Criteria:

• • Age between 18 and 75 years

  • Partial edentulism in the maxilla or mandible involving 1-6 missing teeth, with no more than three adjacent missing teeth
  • Clinical conditions suitable for implant placement as assessed by the investigator or principal investigator (adequate bone and soft tissue conditions and acceptable occlusion)
  • Ability to communicate effectively with the investigators and willingness to comply with study procedures
  • Provision of written informed consent

Exclusion Criteria:

• • Pregnancy or breastfeeding

  • Women of childbearing potential without adequate contraception (for radiological safety reasons)
  • Conditions preventing safe intraoral manipulation (e.g., limited mouth opening, pronounced gag reflex)
  • Current or previous bisphosphonate therapy
  • History of radiotherapy involving the maxilla or mandible
  • International normalized ratio (INR) > 2.5
  • Known HIV, hepatitis B, or hepatitis C infection
  • Known allergy to any component of the implant or surgical guide system
  • Poor oral hygiene
  • Substance abuse
  • Smoking
  • Untreated periodontal disease
  • Any systemic disease or condition judged by the principal investigator to pose an unacceptable risk to the participant or to compromise study completion