Table 1 Search strategy (developed for searching Medline)

1. exp universal health care/

2. ((universal adj2 (health or coverage or insurance)) or (social* adj2 (coverage or insurance))).tw,kf.

3. (essential adj2 (healthcare or health care)).tw,kf.

4. exp Universal Health Insurance/

5. (essential adj2 (healthcare or health care)).tw,kf.

6. or/1–5

7. exp Dentistry/

8. exp Oral Health/

9. exp Stomatognathic Diseases/

10. exp Dental Health Services/

11. (dentist* or denturist* or ((dental or oral) adj3 (health or care or surgeon? or office? or clinic? or assistant? or nurse? or hygien* or practitioner? or professional? or auxiliar*))).tw,kf.

12. (dentist* or endodont* or orthodonti* or periodont* or prosthodont* or oropharyng* or jaw or jaws or mandibular or maxillofacial or mandible* or maxilla* or tooth or teeth or odontolog* or tongue* or glossal or buccal or palatal or palate or palates or labial or lip or lips or gingiva* or gingiviti* or halitosis or bad breath or DMF).tw,kf.

13. or/7–12

14.6 and 13