Comparative evaluation of retentive capacity of three different attachment systems for implant retained overdentures: An in vitro study

Table 1 Evolution of retention strength in all groups according to number of insertion/de-insertion cycle, ball attachment system, equator attachment system, and locator attachment system

Cycles	Min	Max	Mean	Standard deviation	Mean differences	Change, %	P value	P value vs 1 cycle
Ball attachment system
1	21.8	23.9	22.620	0.7899			0.001 (S)
7500	12.0	15.1	17.390	0.7430	5.23	23.1		0.001 (S)
15000	15.9	18.5	13.78	0.79	8.84	39.1		0.001 (S)
Equator attachment system
1	17.4	20.1	19.200	0.7318			0.001 (S)
7500	12.5	14.2	13.22	0.48	5.98	31.1		0.001 (S)
15000	10.3	12	11.2	0.53	8	41.6		0.001 (S)
Locator attachment system
1	21.4	23.6	22.460	0.7230			0.001 (S)
7500	13.5	14.8	14.3	0.46	8.16	36.3		0.001 (S)
15000	11.3	12.7	11.79	0.37	10.67	90.5		0.001 (S)

Table 2 Kruskal-Wallis test results (P < 0.05) and mean values

Circles	P value
Initial	0.001
500	0.2
1500	0.001
3000	0.001
4500	0.001
6000	0.001
7500	0.001
9000	0.001
15000	0.001