Table 2.

Analysis of survival rates of implants and overdentures in case of 4 splinted implants

Study	No.implants for patient, location	Pre-implant bone augmentation	Anchorage system	Bar Fabrication	Follow up(months)	Total no. impl	Total no. lost impl	Survival rate of implants (%)	Total no. OVD	Survival rate of OVD (%)
Slot et al. [19]	4, posterior region	Sinus floor	Milled titanium bar with mesial extensions and gold retentive clips	Abutment level	60	116	0	100	29	100
Slot et al. [20]	4, anterior region	No	Milled titanium eggshaped bar with distal extensions	Abutment level	60	96	0	100	24	100
Slot et al. [21]	4, posterior region	Sinus floor	Milled titanium bar with mesial extensions, and gold retentive clips	Abutment level	12	132	0	100	33	100
Slot et al. [22]	4, anterior region	No	Milled titanium eggshaped bar with distal extensions	Abutment level	12	96	0	100	24	100
Boven et al. [23]	4, anterior region	Some sinus floor	Milled titanium eggshaped bar with distal extensions	Abutment level	12	96	2	97.9	24	100
Krennmair et al. [25]	4, anterior region	No	Titanium or gold bar with distal extensions and retentive clips	Abutment level	42	64	0	100	16	100
Zou et al. [26]	4, ND	No	Dolder gold bar	Abutment level	36	40	0	100	10	100
Mangano et al. [27]	4, anterior region	No	Cobalt-chrome bar, without extensions and gold retentive clips	Abutment level	36	112	3	97,4	28	93,3
Katsoulis et al. [28]	4, ND	No	Titanium or dolder gold bar with distal extension	Implant level	24	88	1	98,9	22	100
Mangano et al. [29]	4, anterior region	No	Eggshaped dolder gold bar with or without distal extensions	Abutment level	60	152	4	97,4	38	100
Akca et al. [30]	4, ND	No	Eggshaped dolder gold bar with distal extensions	Implant level	59	44	1	97,7	11	88
Ferrigno et al. [10]	4, anterior and posterior regions	Some sinus floor	Dolder bar	ND	120	64	6	86,9	16	87,5
Park et al. [31]	4, anterior region	No	Hader bar and bar clips	Abutment level	12	64	1	96.3	16	100

OVD: overdenture. ND: not determined