There are tree separate know sources for Kentala surname
Kaustinen, Ostrobotnia, Finland the Kentala name comes from Swedish word Gedda meaning pike. The most of the known Kentalas can be tracked down Kaustinen area.
Teuva, Finland there has been a farm called Kentta, Kenttala, Kentala. This group of Kentala may still exist?
Oulu, Finland. Kenttala. I do not know the source of the name. Some of the Kentalas in Michigan, US belong to that group.