Table 3.

Description of key methodologies and findings reported in studies that used a payment card and choice methodology

Publication Title	Author (Year of Publication) Location	Sample group (Sample Size)	Methodology: Pre-testing, Reliability	Mode of WTP elicitation	Results (key findings on WTP)
Are people who still have their natural teeth willing to pay for mandibular two-implant overdentures?	Srivastava, A., Feine, J.S. et al (2014) Canada	General Public (39)	Questionnaire was discussed with two experts in the fields of health economics and prosthodontics for content validity Pretested to assess comprehensibility and the time needed (2 individuals)	Questionnaire (web-based)	Average WTP out of pocket for implant overdentures was CAD$5419 for a 90% success rate. Respondents were willing to pay an average CAD$169 as one-time payment for private dental insurance, with a 20% chance of becoming edentate. WTP amounts increased with the probability of success of implant overdenture therapy. For an out of pocket payment method (at 90% success rate), Linear regression analysis showed that opting for implants (β=2.01; p= 0.045) was significantly associated with a higher WTP than not opting for implants and a less than university education respectively.
Attractiveness, acceptability, and value of orthodontic appliances	Rosvall, M.D., Fields, H.W. et al (2009) USA	General public (for self, child) (50)	3 image-rating pages shown twice to evaluate intrarater reliability (all respondents)	Questionnaire (computerized)	Adults were willing to pay an additional mean estimate of $629 for lingual orthodontics, and $167 for hybrid self-ligating appliances.
Esthetic perception and economic value of orthodontic appliances by lay Brazilian adults	Feu, D., Catharino, F. et al (2012) Brazil	General public (for self, child) (252)	-	Face-to-face interview	The correlation between WTP and aesthetic perception was weak (Rho=0.141; p=0.002).
Factors affecting direction and strength of patient preferences in treatment of molar teeth with nonvital pulps	Vernazza, C.R., Steele, J.G. et al (2015) UK	Patients (potential) (503)	-	Face-to-face interview	53% of the sample wished to save the tooth with a mean WTP of £372.79 (SD=991.46). Under the Heckman’s selection model of WTP, it was found that a high income was associated with a higher WTP than that for middle and low income (B(95%CI)=213.56(59.33-367.80); p=0.007)
Putting your money where your mouth is: Parents' valuation of good oral health of their children	Vermaire, J.H., van Exel, N.J.A. et al. (2012) Netherlands	Parents (290)	-	Questionnaire (Written)	Although parents overall highly valued oral health for their child, 12% of parents were unwilling to spend any money to maintain good oral health for their children. Linear regression analyses found that willingness to invest time in brushing (β=0.292; p<0.001) and willingness to invest time in visits to the dentist (=0.198; p=0.03) were significantly correlated with WTP.
Which factors influence willingness-to-pay for orthognathic treatment	Smith, A.S. & Cunningham, S.J. (2004) UK	General public (100), Orthogna thic patients (88)	Repeat interview after 6-8 weeks (20 respondents)	Interview	Patients were willing to pay €2750 more than members of the general public for orthognathic treatment (p=0.009). Linear regression analysis showed that malocclusion type was significantly associated with WTP (p=0.03). Class II div I patients were prepared to pay €3130 more than those with Class III malocclusions.