Use of rubber dam versus cotton roll isolation on composite resin restorations’ survival in primary molars: 2-year results from a non-inferiority clinical trial

Table 4 Evaluation of the baseline and 2-year incremental cost between groups and number of surfaces over time using Bootstrap regression analysis (1000 repeats) using Linear Regression considering the child level

Cost analysis	Mean US$ (SD)	Univariate analysis		Adjusted analysis
Cost analysis	Mean US$ (SD)	Coefficient (SE) 95% CI	p value	Coefficient (SE) 95% CI	p value
Baseline Total Cost
Study Groups
RDI (ref)	17.65 (6.62)	− 6.88 (0.89)	< 0.001*	− 6.95 (0.93)	< 0.001*
CRI	10.76 (5.09)	− 8.64 to − 5.12		− 8.79 to − 5.11
Number of surfaces
Single (ref)	12.65 (5.97)	2.01 (1.04)	0.053	2.28 (0.76)	0.003*
Multiple	14.67 (7.03)	-0.02 to 4.06		0.77–3.78
2 years Total Cost
Study Groups
RDI (ref)	24.62 (19.42)	− 8.51 (2.44)	< 0.001*	-8.69 (2.45)	< 0.001*
CRI	16.11 (10.64)	− 13.30 (− 3.72)		− 13.49 to − 3.88
Number of surfaces
Single (ref)	15.95 (7.25)	5.83 (1.89)	0.002*	6.16 (1.94)	0.001*
Multiple	21.79 (17.98)	2.11–9.56		2.36 to 9.97

CI = Confidence interval; SE = Bootstrap Standard error; SD = standard deviation; *p < 0.05
All costs were measured in Brazilian reais (R$) and converted to US Dollars (US$) using purchasing power parities (PPP)– Conversion rate 1US$ = 2.311R$

ISSN: 1472-6831