## 3 Results
### Calcium Phosphate  
In total, 3 of the 41 studies provided data for calcium phosphate in relation to infection complication risk as per the selection criteria. Implant number varied between 16 and 92 implants. This is shown in Table 9.  
Infection rates varied between 0.00% and 18.75%, with an average infection rate of 6.70%, a standard deviation of 8.04% and a relative risk of 0.64.  
Much like HA, calcium phosphate cranioplasty implants are considered to have strong regenerative and reintegration properties. Given these properties, and the materials relatively porous nature [66; 67] it is given and ISF rank of 2 and TAB rank of 2.  
Table 10 and Figure 1 provide a source of comparison between material, manufacturing method (where applicable), infection rate, estimated ISF and TAB values and relative risk. This table highlights variation between materials in regards to total infection risk, however, depending on the materials compared, this value may be insignificant.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Paper** & **Number of Implants** & **Number of Infection** & **Average Infection Rate (\%)** \\ \hline
[8] & 12 & 0 & 0.00 \\
[6] & 7 & 1 & 14.29 \\
[60] & 69 & 5 & 7.25 \\
[20] & 7 & 0 & 0.00 \\
[61] & 23 & 1 & 4.35 \\ Total: & 118 & 7 & 5.93 \\ Standard Deviation: & - & - & 5.33 \\ Relative Risk: & 0.57 & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 8: Polyethylene (PE).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Paper** & **Number of Implants** & **Number of Infections** & **Average Infection Rate (\%)** \\ \hline
[64] & 92 & 0 & 0.00 \\
[65] & 71 & 9 & 12.68 \\
[66] & 16 & 3 & 18.75 \\ Total: & 179 & 12 & 6.70 \\ Standard Deviation: & - & - & 8.04 \\ Relative Risk: & 0.64 & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 9: Calcium Phosphate.  
Table 11 highlights the results of the one-way ANOVA test conducted.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Material** & **Number of** **Implants** & **Number of Infections** & **Average Infection Rate (\%)** & **Interactive Surface Form (“ISF”)** & **Tissue Attachment Bioactivity Rank (“TAB”)** & **Relative Risk** \\ \hline Autologous & 686 & 72 & 10.5 & 0 & 0 & 1.00 \\ Bone * & & & & & & \\ \hline PMMA (hand-formed) * & 282 & 31 & 10.98 & 0 & 0 & 1.05 \\ \hline Titanium (plate) & 638 & 53 & 8.31 & 0 & 0 & 0.79 \\ \hline PEEK & 152 & 12 & 7.89 & 0 & 0 & 0.75 \\ \hline Titanium (mesh) & 415 & 32 & 7.71 & 1 & 0 & 0.73 \\ \hline PMMA (prefabricated) & 274 & 19 & 6.99 & 0 & 0 & 0.66 \\ \hline PMMA (templated) * & 102 & 7 & 6.86 & 1 & 0 & 0.65 \\ \hline Calcium-Phosphate & 179 & 12 & 6.7 & 2 & 2 & 0.64 \\ \hline PE & 118 & 7 & 5.93 & 3 & 0 & 0.57 \\ \hline HA & 1765 & 36 & 10.5 & 0 & 0 & 0.19 \\ \hline \hline \end{tabular}  
* Indicates implant formation via direct handling of the implant material in surgery;
* Indicates implant formation via custom molding template in surgery.  
\end{table}
Table 10: Craniplasty/craniofacial implant material: comparison of associated infection risk, surface form and tissue attachment.  
Figure 1: Craniplasty/craniofacial implant material: comparison of associated infection risk, surface form and tissue attachment. * Indicates implant formation via direct handling of the implant material in surgery; + Indicates implant formation via custom molding template in surgery.  
There were not found to be statistically significant differences between all implant material infection rate means as ascertained by one-way ANOVA (\(p=0.12\)).