Yes, putting a case on the device will help. However please keep in mind if any repair's or adjustments are done to any iOS devices via a Non Apple Authorized personal then the warranty that the device comes with will be voided. Once the warranty is voided Apple will not replace/repair or do any services to that device.
Also dents of any small or large size, are considered as 'Accidental Damage' which also is not covered by the 1 year limited warranty that comes with a newly purchased iOS device. If you by chance purchased the AppleCare Protection Plan + before 60 days are up from the date of the purchase for the device, then this does have 2 accidental replacement's which will only cost your around $80 to get replaced rather than paying $299<-'iPhone 6' - $329<-'iPhone 6 Plus'.
Wanted to throw this out for you, recently learned this myself.