# Retentive Behavior of Locator versus Ball Attachments on Parallel versus Non-Parallel Implants
## 3 Results  
Descriptive statistics for all measurements are given in Table 1. Measurement values could be assumed as being continuous and normally distributed as Shapiro tests showed only one significant value (Clix abutment, parallel implants, white insert \(p\) = 0.03). The results of [PERSON]'s _t_-tests for comparing parallel vs. tilted configurations are given in Table 2, and the results for comparing the different plastic inserts using ANOVAs and [PERSON]'s Honest Significant Difference tests are given in Table 3.  
In the group of locator attachments, the divergent implant model always led to lower retentive forces as compared with the parallel situation (Figure 4). This effect ranged between a reduction of 21.8% (white) and 39.1% (blue) and was statistically significant for all inserts (_p_ < 0.004; Table 1(a)). The standard deviations in the group of locator abutments ranged between 8% and 23%. An increase in retentive force was observed from blue to pink and white female plastic inserts both in the parallel and the divergent implant situation, with only the difference between white and pink inserts on parallel implants not reaching statistical significance (_p_ = 0.088; Table 2). The absolute values for retention force could, however, not be related to the values provided by the manufacturer for single attachments.  
In general, for the Clix abutments, lower retentive values were measured as compared with the locator (Figure 4). The shift from white to yellow plastic inserts almost doubled the retention force (parallel implants: 23.16 N vs. 45.36 N; tilted implants: 24.46 N vs. 41.74 N), which reached statistical significance (_p_ < 0.000; Table 3). The maximum standard deviation observed in this group was 7%. The minor (below 10% change) effects on retention force were seen when tilted implants supported the attachments as compared with parallel implants when the female attachment parts had been aligned. With yellow inserts, however, the difference between parallel and tilted configurations was statistically significant (_p_ = 0.040; Table 2). Not aligning the female retentive parts placed on tilted implants led to an increase in retention force of 6.5%, which was not statistically significant (_p_ = 0.100; Table 1(a)).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Group** & **Minimum** & **Mean** & **Median** &
\begin{tabular}{c} **Standard** \\ **Deviation** \\ \end{tabular} & **Maximum** \\ \hline Locator blue parallel a,e,g & 49.86 & 66.78 & 68.47 & 11.10 & 86.67 \\ \hline Locator blue tilted a,f,h & 24.30 & 40.63 & 43.24 & 9.34 & 54.30 \\ \hline Locator pink parallel b,e & 82.17 & 103.30 & 108.30 & 12.83 & 123.97 \\ \hline Locator pink tilted b,f,i & 52.16 & 69.62 & 64.29 & 12.94 & 92.85 \\ \hline Locator white parallel c,g & 98.14 & 120.35 & 122.10 & 10.50 & 138.25 \\ \hline Locator white tilted c,h,i & 79.36 & 94.09 & 93.87 & 7.20 & 107.27 \\ \hline Clix white parallel j & 21.56 & 23.16 & 23.48 & 0.74 & 24.11 \\ \hline Clix white tilted k & 21.70 & 24.46 & 24.41 & 1.68 & 27.33 \\ \hline Clix yellow parallel d,j & 42.44 & 45.36 & 45.08 & 2.02 & 49.71 \\ \hline Clix yellow tilted d,k & 38.21 & 41.74 & 41.93 & 2.48 & 46.44 \\ \hline Clix yellow tilted—not adjusted & 40.36 & 44.44 & 44.95 & 2.29 & 52.31 \\ \hline \hline \end{tabular} Note: identical letters indicate statistically significant differences between groups.  
\end{table}
Table 1: Retention forces [N] calculated as descriptive statistics for all experimental groups.