Periodontitis is a chronic inflammatory disease and individuals with advanced periodontitis have an increased risk of hyperglycaemia. Bacterial plaque, smoking and elevated blood glucose levels are considered key modifiable risk factors for periodontal disease progression. Conventional periodontal care aims to remove and control bacterial deposits and to smoking cessation. Despite the bidirectional relationship, where periodontitis may also contribute to impaired glycaemic control, glycaemic status is rarely niether assessed nor adressed in dental care.

The aim of this project is to implement and evaluate routine blood glucose testing as part of the periodontal examination in specialist dental care. Patients diagnosed with advanced periodontitis (Stage III or IV according to the current classification) will be offered capillary blood glucose testing during their periodontal assessment.

The objectives of this study are to determine the prevalence of hyperglycaemia among patients with advanced periodontitis and to evaluate clinician-reported and patient-reported experiences of routine blood glucose testing as part of the periodontal assesment in specialist periodontal care.

Periodontitis is a chronic inflammatory disease affecting the supporting structures of the teeth and represents one of the most prevalent non-communicable diseases worldwide. Epidemiological studies show that population-level preventive strategies targeting dental biofilm control and smoking cessation have contributed to improvements in periodontal health, these measures have not resulted in a significant reduction in the prevalence of advanced periodontitis over the last decades. Individuals who develop severe and rapidly progressing periodontal disease have an increased susceptibility to plaque induced inflammation and hyperglycemia seem to play a central role as a modifyer of that susceptability.

A bidirectional relationship between hyperglycemia and periodontitis has been well established. Elevated blood glucose levels are associated with increased risk of periodontal tissue breakdown, impaired wound healing and accelerated disease progression, while periodontal inflammation may affect glycemic control. Hyperglycemia is therefore not only a systemic health concern but also a clinically relevant, modifiable risk factor that directly influences periodontal prognosis. Contemporary periodontal classification systems explicitly incorporate glycemic status into disease grading, emphasizing the importance of identifying and addressing this risk factor in patients with advanced disease.

Despite this recognized relationship, routine assessment of glycemic status is rarely performed in dental settings in Sweden, largely due to the absence of established protocols and access to point-of-care testing. This represents a missed opportunity, particularly within specialist periodontal care, where patients with Stage III and IV periodontitis are identified through comprehensive periodontal examinations. A substantial proportion of individuals with type 2 diabetes or prediabetes remain undiagnosed, and many of these individuals may seek dental care more regularly than medical care. Specialist periodontal clinics may therefore serve as a valuable setting for selective screening of hyperglycemia in a clearly defined high-risk population.

The present study aims to integrate capillary HbA1c testing as a routine in periodontal assessment within specialist dental care and to evaluate its ability to identify previously unrecognized hyperglycemia or suboptimal glycemic control as well as investigate the the patients and dentists experience of that routine. The study is designed as a cross-sectional observational investigation conducted at the Department of Periodontology, Eastman Institute, Stockholm, over a 12-month period.

Eligible participants are adult patients referred for evaluation and treatment of periodontitis who, following a full periodontal examination and radiographic assessment, are classified as having Stage III or Stage IV periodontitis according to current classification criteria. Patients who are unable to provide informed consent, have cognitive impairment or present with periodontitis as a manifestation of systemic disease or syndrome are excluded. To ensure informed participation, only patients able to understand written and spoken Swedish are included.

Following confirmation of eligibility, patients are provided with oral and written information about the study and written informed consent is obtained. Capillary blood sampling is performed using a finger-prick method with a single-use lancet, and HbA1c is analyzed chair-side using a validated point-of-care device. The test does not require fasting or other patient preparation and is conducted in direct conjunction with the periodontal examination. The biological sample is not stored; only the test result is recorded in the patient's dental record.

Participants receive individualized feedback regarding their HbA1c result. For patients without a known diagnosis of diabetes who present with HbA1c values above the predefined threshold indicating hyperglycemia, information is provided regarding the potential risk of diabetes or prediabetes, and the patient is advised to contact primary care for further medical evaluation. Patients with known diabetes who exhibit HbA1c values indicating suboptimal glycemic control are encouraged to consult their diabetes care provider. In all cases, it is clearly communicated that the dental assessment does not constitute a medical diagnosis but serves as an indication warranting further evaluation.

In addition to HbA1c, clinical data are collected, including age, sex, smoking status, number of remaining teeth, bleeding on probing, number of periodontal pockets ≥6 mm, furcation involvement, and periodontal classification. These variables enables interpretation of glycemic findings in relation to periodontal disease severity. All data are recorded in a pseudonymized format for statistical analysis.

To capture the experience of the routine, patients are asked to complete a brief questionnaire assessing perceived meaningfulness associated with the blood sampling procedure. Dental staff involved in the procedure similarly assess perceived meaningfulness and time requirements. These qualitative measures provide insight into the practicality of implementing glycemic screening as a routine of specialist periodontal care.

The primary outcome measure is HbA1c expressed in mmol/mol, analyzed as a continuous variable and categorized according to established clinical thresholds. Secondary outcomes include the prevalence of previously undetected hyperglycemia among patients without known diabetes and the prevalence of inadequate glycemic control among patients with known diabetes. Descriptive statistical analyses are used to summarize HbA1c distributions and prevalence estimates in relation to periodontal characteristics. All analyses are conducted on pseudonymized datasets, and results are reported in aggregate form.

From an ethical perspective, the study is considered low risk. The capillary blood sampling procedure is minimally invasive and widely used in routine healthcare. Potential psychological discomfort related to identification of elevated HbA1c values is acknowledged; however, this risk is weighed against the benefit of early detection of hyperglycemia and the prevention of long-term diabetes-related complications. Selective screening restricted to patients with objectively verified advanced periodontitis is intended to reduce the risk of unnecessary referrals.

Personal data are handled in accordance with data protection regulations and guidelines. Identifiable data are stored securely within authorized clinical systems, while research datasets used for analysis are pseudonymized. No biological material is stored after analysis. Responsibility for data processing lies with the healthcare provider, and all research documentation is archived in accordance with institutional record-keeping requirements.

By integrating glycemic assessment into specialist periodontal evaluation, this study explores a model for interdisciplinary prevention that aligns oral health care with broader public health objectives. The findings are expected to inform future clinical routines and contribute to the development of evidence-based protocols for selective metabolic screening within dental specialist settings.

Inclusion Criteria:

• adult patients >18 years
• classified as having Stage III or Stage IV periodontitis (according to current international criteria)

Exclusion Criteria:

• Patients who are unable to provide informed consent because of significant cognitive impairment or unable to understand written and spoken Swedish
• Patients with periodontitis as a manifestation of systemic disease or syndrome

Adult patients referred for evaluation and treatment of periodontitis at the specialist clinic Folktandvarden Eastmaninstitutet who, following a full periodontal examination and radiographic assessment, are classified as having Stage III or Stage IV periodontitis according to current international criteria.