![Figure 12.](/ServeContent?url=http%3A%2F%2Fdbm.sagepub.com%2Fcontent%2F5%2F1758736014552149%2FF12.medium.gif)
Figure 12.
A modification of butterfly arch for excellent maintaining of transverse dimension.
(Downloading may take up to 30 seconds. If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.