A clinical and radiographic study of implants placed in autogenous bone grafts covered by either a platelet-rich fibrin membrane or deproteinised bovine bone mineral and a collagen membrane: a pilot randomised controlled clinical trial with a 2-year follow-up

International Journal of Implant Dentistry

Table 2 Radiographic peri-implant marginal bone level in mm

	Test group			Control group			Mean difference	95% CI	p value
	Obs	Mean	95% CI	Obs	Mean	95% CI	Mean difference	95% CI	p value
Baseline	14	− 0.24	− 0.48 to 0.00	13	− 0.28	− 0.52 to 0.03	0.04	− 0.314 to 0.39	p = 0.82
Abutment	14	0.07	− 0.17 to 0.30	13	− 0.01	− 0.26 to 0.25	0.08	− 0.278 to 0.43	p = 0.66
Impression	14	0.15	− 0.09 to 0.39	13	0.20	− 0.05 to 0.44	− 0.05	− 0.40 to 0.30	p = 0.79
Follow-up	13	0.26	0.01 to 0.50	10	0.68	0.41 to 0.96	− 0.43	− 0.80 to − 0.05	p = 0.03

Baseline: the time of implant placement; abutment: the time of abutment operation; impression: the time of impression taking; follow-up: the time of follow-up. Negative values indicate that the implant-abutment connection was below the marginal bone level. The p values were calculated using post-hoc tests following the mixed model for repeated measurement