Until now it has not been investigated whether placement of implants in SS patients is less successful than compared to non-SS patients. The risk factors and the efficacy of dental implants in dry mouth patients are not known because of the lack of scientific evidence. The aim of this study is to investigate changes in marginal peri-implant bone loss and the clinical performance of dental implants in SS patients compared to implants in healthy patients.

Rationale: Until now it has not been investigated whether placement of implants in SS patients is less successful than compared to non-SS patients. The risk factors and the efficacy of dental implants in dry mouth patients are not known because of the lack of scientific evidence.

Objective: to investigate changes in marginal peri-implant bone loss and the clinical performance of dental implants in SS patients compared to implants in healthy patients.

Study design: A prospective multicenter clinical trial.

Study population: N = 120

Intervention: All patients receive Biohorizons Laser-lok bonelevel implants to replace the missing (pre)molars or to support a full denture in the upper and lower jaw .

This study is comprised of four study groups:

• 30 human adults affected by SS with the need of replacement of missing premolars or molars in the upper or lower jaw.
• 30 healthy human adults with the need of replacement of missing premolars or molars in the upper or lower jaw.
• 30 human edentulous adults affected by SS with the need of stabilization of the dentures.
• 30 healthy human edentulous adults with the need of stabilization of the dentures.

Main study parameters/endpoints: changes in marginal peri-implant bone loss of dental implants between the healthy and SS groups and differences in clinical performance 1.5 years after finalization.

Inclusion criteria (dentate group, Sjögren):

• The patient is at least 18 years and younger than 70;
• A diagnosed (by the AECG guidelines; see attachment; Vitali et al., 2002) primary or secondary Syndrome of Sjögren;
• The missing or lost tooth/teeth are premolars and/or molars in the upper or lower jaw.
• Sufficient healthy and vital bone to insert a dental implant with a minimum length of 8 mm and at least 3.8 mm in diameter. In case of insufficient bone volume, a bone augmentation procedure will be performed with autologue bone. If necessary the autologue bone can be mixed with artificial bone (artificial bone graft substitutes in combination with a membrane).
• The implant site must be free from infection;
• Adequate oral hygiene (modified plaque index and modified sulcus bleeding index ≤ 1) (Mombelli et al., 1987; Loe and Silness, 1963)
• Sufficient mesio-distal, bucco-lingual, and interocclusal space for placement of an anatomic restoration;
• The patient is capable of understanding and giving informed consent.

Inclusion criteria (edentulous group, Sjögren):

• The patient is at least 18 years and younger than 70;
• A diagnosed (by the AECG guidelines; Vitali et al., 2002) primary or secondary Syndrome of Sjögren
• The patient is edentulous. Before final inclusion in the study the patient has to be edentulous for 1 year.
• Problems with conventional denture retention, stability and/or adaptation, which could be solved by an implant, supported denture (lower or/and upper jaw).
• Sufficient healthy and vital bone to insert dental implants with a minimum length of 8 mm and at least 3.8 mm in diameter. In case of insufficient bone volume, a bone augmentation procedure will be performed with autologue bone. If necessary the autologue bone can be mixed with artificial bone (artificial bone graft substitutes in combination with a membrane).
• The implant site must be free from infection;
• Capable of performing adequate oral hygiene;
• The patient is capable of understanding and giving informed consent.

Inclusion criteria control groups:

- The inclusion criteria for the healthy control groups are similar as for the Sjögren groups without the Sjögren criterion.

Exclusion criteria:

Criteria used for excluding patients from this study are as follows:

• Medical and general contraindications for the surgical procedures;
• Presence of an active and uncontrolled periodontal disease as expressed by probing pockets depths > 4mm with bleeding upon probing;
• Smoking (patients who stop smoking six weeks before the operation can be included);
• A history of radiotherapy to the head and neck region;
• Use of intravenous bisphosphonates or the use of oral bisphosphonates for more than 5 years.