The first ever Fitness to Teach inquiry has heard five students had red marks on their faces, after a teacher allegedly made them put sellotape on their mouths.
The teacher, who was subbing at the time, denies the allegations - saying the girls tapped their mouths themselves.
A three-member panel now has to decide if the teacher engaged in professional misconduct or not.
the five girls at the centre of this case are now teenagers but at the time they were in 5th class.
They told the inquiry there was messing and laughter in maths one day, and the teacher told them to 'whisssht' and threatened to put sellotape over their mouths.
It is then alleged the teacher did put tape on the mouths of some of the girls, or they did it themselves as they felt they had to.
The school principal told the inquiry the girls were a bit shook afterwards, had little red marks around their mouths and one or two of them were crying.
The hearing is being held in public but the teacher's identity, the name of the school and all witnesses are protected.
The hearing has been set down for two days.
Since the ‘Fitness to Practice’ legislation took effect last July, the Teaching Council has received around 50 complaints - but only half of those have been investigated further.
This case is the first to go to a full hearing.
Anyone including colleagues, parents and even children can make a complaint but those considered frivolous or vexatious will not be pursued.
The council has the power to strike a teacher off the professional register, but lesser penalties include suspension and an offer of support to improve performance.
The legislation provides for hearings to be held in public but they can also be held in private - either in full or in part.