It's possible that the content is still in the database, and isn't being displayed because the new template uses different area names. Try changing the template back to how it was.

...and take another backup (without over-writing your previous backup), just in case things get worse.

I reverted to the previous template but the pages still didn't show up.

I also noticed that it is indeed dangerous to change a page template because of the 99% risk to loose your content.

Your content still exists in the database. You just have to make sure the new template you switched to has the same content areas names you used in the old template.

Would I have to dive into the hard coded templates to check this out ?

Hello @Gondwana and @stewblack23,

Thank you for your quick reply. Both your replies make sense but I have changed the pagetype back to the former template only to notice that my content hadn't come back.

Since it was a quite urgent matter, I restored from the backup I made early in the morning.

And I'll investigate more how can such thing can be avoided, as it may happen to everyone.

Thanks