Dental Panoramic Radiographs to Screen for Post-menopausal Osteoporosis

Background:

The World Health Organization (WHO) has defined osteoporosis as a level of bone mineral density (BMD), calculated with DXA (Dual-energy X-ray absorptiometry) technique, 2.5 standard deviations (SD) or more below the average mean value of young healthy women (T-score ≤ -2.5) (Kanis et al., 2013).

Although the WHO reports that there is indirect evidence supporting screening programs in women aged 65 or older, current Italian national guidelines do not recommend population-screening programs for osteoporosis (SIOMMMS 2015). As a consequence, a significant part of Italian osteoporotic patients that may develop a fracture is left undetected and untreated. Although it is recommended to assess risk of osteoporotic fractures with the WHO FRAX tool in all women ≥65 years and men ≥75 years and refer for DXA accordingly, it is not clear how well this tool has been adopted by general practitioners (GPs) in Italy.

Considering the high percentage of people attending regular dental visits (> 22 million according to ISTAT 2013) and the fact that panoramic radiographs of the jawbones are a common procedure that is performed during routine dental check-ups or before several dental treatments, it could be of great clinical value if dentists could opportunistically use panoramic X-rays to identify patients at a high risk of osteoporosis.

In the past years, specific quantitative and qualitative indices/parameters, which can be calculated on dental panoramic radiographs, have been proposed as tools to detect osteoporosis, with different levels of accuracy.

Amongst the quantitative indices, the most adopted ones are the mandibular cortical width (MCW) and the panoramic mandibular index (PMI). The MCW represents the width of the mandibular cortex and it is measured in the mental foramen region, along a line passing through the middle of the mental foramen and perpendicular to the tangent to the lower border of the mandible. The PMI represents the ratio between the mandibular cortical width at mental foramen region and the distance from the lower border to the inferior edge of the mental foramen.

Amongst the qualitative indices, the Klemetti index (KI) is by far the most applied one. KI qualitatively classifies the mandibular cortex distally to the mental foramen in the following categories: C1, when the endosteal margin is even and sharp; C2, when the endosteal margin presents lacunar resorption or cortical residues on one or both sides; and C3, when the cortical layer is clearly porous, with heavy endosteal cortical residues. A recent systematic review and meta-analysis from our group showed that the presence of any kind of cortical porosity (C2+C3) is associated to a sensitivity and specificity in detecting osteoporosis of 80.6% and 64.3%, respectively. The advantage of using this index, compared to other available indices, is that it is straightforward and relatively easy to measure and it does not require specific softwares.

It is clear that the panoramic indices cannot replace the diagnosis of osteoporosis by BMD measurement with DXA scan. However, whenever a panoramic radiograph is available, they might be opportunistically used to detect previously undiagnosed osteoporotic patients and refer them to a specialist before they develop a fracture.

While several studies support the use of panoramic indices, they have never been tested in an Italian University Hospital setting and in a study adequately powered and controlled for confounding variables.

Study description:

This is cross-sectional observational study aiming to recruit a cohort of 124 consecutive post-menopausal women. The only study visit will take place at the "Centro Universitario di Odontoiatria, Dipartimento di Medicina e Chirurgia, Università di Parma".

All post-menopausal women ≥ 65 years old attending the Centro Universitario di Odontoiatria in the new patients' or follow-ups' clinics will be approached to check for the inclusion/exclusion criteria and their willingness to take part in the study. Furthermore, doctors (general practitioners or osteoporosis specialists) will be contacted and will be kindly asked to inform their patient that had done a DXA scan within the past 12 months about the study. Potentially eligible patients will be booked an appointment at the "Centro Universitario di Odontoiatria, Dipartimento di Medicina e Chirurgia, Università di Parma" to check for inclusion/exclusion criteria and for the recruitment. As part of the study, they will receive a full-mouth examination of the hard and soft tissues and an OPG at no cost.

Only 1 study visit will be performed.

Visit 1 (Data collection)

• Signing of informed consent;
• Recording of any concomitant medication;
• Confirmation of participant eligibility in relation to the inclusion/exclusion criteria;
• Examination of hard and soft tissues;
• Full-mouth six-points periodontal chart, with recording of probing pocket depth (PPD), recession (REC), furcation involvement and mobility.
• Dental panoramic radiograph (OPG) if not performed at the Centro Universitario di Odontoiatria within the previous 12 months

Photos of the teeth may be taken to facilitate case documentation. Subjects will not be identifiable.