A Study of the Crestal Bone Loss Around Bone Level Versus Tissue Level Implants in Non-compliant Patients With Healthy or Reduced Periodontium After 5-8 Years in Function

The goal is to evaluate, after 5 to 8 years, the marginal bone loss around tissue-level implants and bone-level implants in patients who have not followed the maintenance program.

Medical records of patients who have been implanted for at least 5 to 8 years and who have been lost during this period are collected from three private clinics in Beirut,Lebanon and the Saint Joseph University Health Center in Beirut,Lebanon.

On an individual sheet, the patient as well as the implants data will be noted. Patients will be called for reevaluation after 5-8 years. After signing the informed consent, the measurements by a PCP-15 probe of the plaque index (FMPS) and the bleeding index (FMBS) as well as the height of the keratinized tissue are indicated on the sheet. If the smoking status has changed, this will be mentioned too.

The marginal bone loss will be measured on the X-rays taken immediately after the implant placement, after 1 year of loading and then at the reevaluation session.

On the individual sheet for each patient, the data concerning the name, age, sex, general condition, smoking status, periodontal status , the number of follow-up sessions and the plaque index as well as bleeding on probing (if noted in the file before placing the implants) will be recorded.

Then, the data concerning the implant such as the site (maxilla or mandibular), the type of implant, the length, the diameter, the surface, sealed or screwed, presence of a cantilever, hiatus or over-contour, a one or two surgical time, the date of placement and the number of years of operation will also be noted on the form.

Patients will be called for reassessment appointments after 5-8 years. After signing the informed consent, the measurements by a PCP-15 periodontal probe of the plaque index (FMPS), bleeding on probing (FMBS) as well as the height and thickness of the keratinized mucosa are indicated on the sheet. The smoking status will also be updated and indicated.

Implants will be classified into one of these groups:

1. Patients with tissue implants (TL).
2. Patients with bone level implants with internal connection (BL, Internal hex).
3. Patients with bone level implants with external connection (BL, External hex).

X-rays taken after insertion, after 1 year of loading and after 5-8 years will be collected and analyzed on the DBSWIN software. Mesial and distal bone loss after implant placement and after 5 to 8 years will be measured on retro-alveolar radiographs with calibration and recorded on the patient file. The total bone loss will then be calculated.

The radiographic measurement technique is as follows. The platform of the mesial and distal implant (MIS: Mesial Implant Shoulder and DIS: Distal Implant Shoulder) will be defined and a line (A) connecting the two is drawn. Another line (B) tangential to the apex of the implant and parallel to A is also drawn. The bisecting line at A and B is therefore produced and measured to assess the distorted implant length (DIL: Distorted Implant Length). Bone level (BL) measurements will be recorded from the implant platform (MIS-DIS) to the most coronary bone-to-implant contact (BIC) on the mesial and distal sides of each implant. The length of the implant will be used as an actual measurement to calibrate the other measurements.

Eligibility Criteria:
Inclusion Criteria:

* Patients who have undergone the initial phase followed by implant placement in the posterior region.
* Implants placed for more than 5 years.
* The implant systems selected are:

  * Tissue Level Implants: Straumann (Straumann Dental Implants System, Switzerland),
  * Bone Level implants: Branemark, 3i Biomet (external and internal connection), Nobel replace and Astra.
* Patients who did not comply with the maintenance program and who missed more than 30% of appointments.

Exclusion Criteria:

* Systemic diseases (uncontrolled diabetes, drugs which may affect bone metabolism).
* Totally edentulous.
* Severe periodontitis not stabilized
* Inappropriate, unavailable or distorted x-rays.
* Augmented sites.
* Implants placed at a supra or infraosseous level.
* Implants placed immediately after extraction.