You Do Need power plug adapter while traveling from Canada to Dominican Republic.

Here is Why You Need An Adapter

The outlet and plug type used in Dominican Republic are A, B and C and in Canada are A and B. This is how they look like.

Canada

In Canada, outlets of type A and B are in use.

Type A

Type B

Dominican Republic

In Dominican Republic, outlets of type A, B and C are in use.

Type A

Type B

Type C