As the previous answers have stated, if one of the master detail records is deleted, it goes in the recycle bin. If both are deleted, well, sorry, but you’re out of luck; it can’t be retrieved at this point. It’s like putting something in the recycle bin on your computer, and then deleting everything from your recycle bin; it’s gone after you delete it from the recycle bin, and you can’t get it back.
Disclaimer: I am not experienced with SalesForce. I cannot say for sure if this is still how it operates, as this answer is hobbled together by double checking the other answers on the help page. If you want to know more, take a SalesForce training or play around with some records made specifically for that purpose.
In Salesforce, there are junction objects. These junction objects are used by those on Salesforce in order to build the relationships in multiple capacities between the things in Salesforce. There are certain times when one thing or object needs to be linked to several different things. Think of applications as if it was for a job. There might be one application which is an object and then there might be several candidates who want to apply.
So, there would be many candidates or objects for that one application. Master records in Salesforce are used to hold the places of other things. So, if the master record is deleted, two things take place. The record is deleted and thrown away and it has two master detail relationships.
The record is deleted and placed in the recycle bin.
Junction object records are deleted when either associated master record is deleted and placed in the Recycle Bin. If both associated master records are deleted, the junction object record is deleted permanently and cant be restored.####