Every teacher in the public schools of a city, town, county or district who has taught in the schools not less than ten (10) years, has contributed for not less than five (5) years annually to the fund, as may be provided under this part, and has become, without the fault of the teacher, mentally or physically incapacitated from such service, may be retired by the school board and become a beneficiary of the fund in the same manner as provided in this part, but such annuity shall cease when the incapacity ceases; however, such incapacity does not include temporary illness.