Primary Sjögren's Syndrome (PSS) is a chronic autoimmune inflammatory disease primarily involving the salivary and lacrimal glands. Few data exist regarding survival and success rate of dental implants in patients with PSS. Although a previous study suggest lower success rate for dental implants we hypothesize that dental implants have similar survival and success rate in PSS as healthy controls.

The purpose of the present study was to evaluate the long-term survival and success rate of dental implants in patients with PSS compared to the healthy controls.

Sjögren's syndrome (SS) affects about 5% of population worldwide. Patients with Primary Sjögren's Syndrome (PSS) have dry mouth, oral mucosal problems, increased dental decay and problems wearing dentures. A retrospective case series indicated that implant survival rate may be reduced among SS patients. Furthermore, there is lack of scientific evidence to support success or failure of dental implants in SS-patients.

The null hypothesis is that the outcome of implant treatment after 5 years is similar in patients with primary Sjögren's Syndrome (pSS) compared to matched controls.

The participants with PSS fulfilled the Copenhagen Criteria and/or the US-EU criteria for PSS, miss at least one tooth and have sufficient bone volume for a single implant insertion without bone augmentation.

Recruitment of PSS patients was done via own existing databases on PSS patients as well as repeated national announcements in the Danish Dental Journal.

We included 24 consecutive participants with PSS. For each participant with PSS (test group), an age, gender, and tooth-type matched healthy participant (control group) was enrolled (n=24).

The surgical part of the implant treatment was carried out by two experienced maxillofacial surgeons. Straumann implants (Straumann Bone level Roxolid®) with a hydrophilic sandblasted, acid etched implant surface (SLActive) was used for all participants. If more than one implant was placed, the study implant was determined according to a randomization scheme.

The inserted implants were allowed to heal for 3 months before the prosthetic part, which was carried out by two experienced prostodontists. The same prosthetic material and method was applied for all participants.

The participants were recalled for baseline (2 months after prosthetic loading) and 1, 3 and 5 years examination, where the biological (marginal bone level, inflammation etc.), technical (fractures, loosening's etc.), esthetic (Copenhagen Index score) and patient-reported (Oral Health Impact Profile questionnaire/OHIP-49) assessments were performed.

Inclusion Criteria:

• - Age 20-70 years

• Indication of tooth replacement with implant-supported fixed dentures

• The test group should be without any potentially associated disease

• pSS must be diagnosed according to the American-European Consensus Group criteria (Vitali et al., 2002):

  1. The presence of any 4 of the following 6 items, as long as either item IV (Histopathology) or VI (Serology) is positive
  2. The presence of any 3 of the 4 objective criteria items (that is, items III, IV, V, VI)

The items:

I. Ocular symptoms: a positive response to at least one of the following questions:

1. Have you had daily, persistent, troublesome dry eyes for more than 3 months?
2. Do you have a recurrent sensation of sand or gravel in the eyes?
3. Do you use tear substitutes more than 3 times a day?

II. Oral symptoms: a positive response to at least one of the following questions:

1. Have you had a daily feeling of dry mouth for more than 3 months?
2. Have you had recurrently or persistently swollen salivary glands as an adult?
3. Do you frequently drink liquids to aid in swallowing dry food?

III. Ocular signs --that is, objective evidence of ocular involvement defined as a positive result for at least one of the following two tests:

1. Schirmer's I test, performed without anaesthesia (<5 mm in 5 minutes)
2. Rose bengal score or other ocular dye score (>4 according to van Bijsterveld's scoring system) IV. Histopathology: In minor salivary glands (obtained through normal-appearing mucosa) focal lymphocytic sialoadenitis, evaluated by an expert histopathologist, with a focus score >1, defined as a number of lymphocytic foci (which are adjacent to normal-appearing mucous acini and contain more than 50 lymphocytes) per 4 mm2 of glandular tissue

V. Salivary gland involvement: objective evidence of salivary gland involvement defined by a positive result for at least one of the following diagnostic tests:

1. Unstimulated whole salivary flow (<1.5 ml in 15 minutes)
2. Parotid sialography showing the presence of diffuse sialectasias (punctate, cavitary or destructive pattern), without evidence of obstruction in the major ducts
3. Salivary scintigraphy showing delayed uptake, reduced concentration and/or delayed excretion of tracer

VI. Autoantibodies: presence in the serum of the following autoantibodies:

1. Antibodies to Ro(SSA) or La(SSB) antigens, or both

• The control group should match the test group according to the age, sex and treatment region and fulfill the following:
• Normal salivary flow: unstimulated > 1.5 ml in 15 min, stimulated > 3.5 ml in 5 min
• No ocular or oral symptoms
• Submission of written informed consent form

Exclusion Criteria:

• Persons with:

  1. secundary Sjögren Syndrom (sSS)
  2. severe systemic disease including severe bleeding disorder and/or conditions which put the patient at risk and/or prohibit compliance as stated by Hwang and Wang, 2006; and Hwang and Wang, 2007):
  3. previous or present bisphosphonate, Denosumab or anti-angiogenetic chemotherapeutic drugs
  4. poor bone quality according to Lekholm U & Zarb GA (1985) or diagnosed osteoporosis
  5. Heavy smokers, eqv. to 20+ cigarettes/day
  6. Noncompliance

The statistical analyses will be masked.