A former Montgomery County music teacher was sentenced to 40 years in prison on Friday for sexually abusing 14 young children at an elementary school.At the hearing, Lawrence W. Joynes spoke publicly about his actions for the first time and described himself as ashamed, frightened and remorseful.Im so sorry I betrayed your faith and your trust in me, said Joynes, a 27-year veteran of the public school system, addressing his former students in a statement.