The purpose of this retrospective study is to investigate and identify factors associated with the failure of dental implants within the population rehabilitated with dental implants at the Folktandvården Specialistklinik in Malmö (Spårvägsgatan 12, 214 27, Malmö).

This is a retrospective study that involves collecting information about the past and comparing that with contemporary information collected from the same cases. The patients' dental records' archive and the digital dental records of the Folktandvården Specialistklinik in Malmö will be scrutinized. The patients will be retraced in the Swedish Personal Data System and will be invited for a recall visit with a clinical and radiographic examination. The patients will then be informed of the design of the study through the reading of the Form for Patient Information and the Informed Consent in Swedish and verbally. In case the patient is not willing to pay a recall visit, only the data of the patient's records will be used, under the patients' approval.

The data from the patients' records will be directly inserted to a computer file of the statistical software Statistical Package for the Social Sciences (SPSS Inc., Chicago, USA). The additional follow-up information from the patients' recall visit will be collected in specific forms and then inserted to the previously mentioned computer file. All dental implants inserted will be included in the study. Data will be categorized as surgical, implant-specific, patient-related, anatomic, loading conditions, prosthetic, and trans- and postoperative complications.

Periapical radiographies of the patients' digital record will be neatly filed in a computer file. Periapical radiographies that could possibly exist in celluloid film will be digitalized. From each patient, additional radiographs will be selected from the patient's record, based on availability in several time intervals. At the recall consultation, new periapical radiographies will be taken. The reference point will be established at the implants-abutment junction, and the marginal bone level measurement will be performed by using the Image J software.

Inclusion Criteria:

• All treated patients with dental implants placed and restored at the Avdelning för Oral Protetik at the Folktandvården Specialistklinik in Malmö with an available dental record;
• Patients having read, understood, and signed the Form for Patient Information and the Informed Consent.

Exclusion Criteria:

• Patients not willing to give their permission to scrutinize their records;
• Lack of enough data in the patients' dental records.

The population rehabilitated with dental implants at/or referred to prosthetic rehabilitation at the Avdelning för Oral Protetik at the Folktandvården Specialistklinik in Malmö.