My father has a 1930 Scarborough, ME school photo. He can remember most of the students and the teacher.
He only knew the teacher as Mrs. Gentner. The teacher had three daughters, also in the picture. Their name were/are Margaret, Burl, and Christine.
My father is 90+ so presume the others would be around that age, or a bit younger.
The marriage records in the online Maine Archives make no mention of any of the daughters. Three female Gentners are listed and one could be the teacher, although none lived near Scarborough when married.