De-escalation is the key to confrontational students. The majority of teachers will never have any problems with one. Teaching is a relatively safe profession. But for upper grades, there is always the risk.
The students are bigger and have different wants and needs. Teachers should be prepared to confront a student who is raising the stakes in the classroom. Dealing with disruptive students should actually start before the disruption. A teacher needs to be well organized and efficient in running a classroom. Above all, have your classroom discipline and classroom management down. You also need to create a positive classroom. If these three are in pace, the chances of you having a confrontation with a student are greatly reduced.
One of the best things you can do with a confrontational student is nothing. At least for a few seconds. Give the student a chance to back away. Above all, do not get angry. Do not lose your cool. You have a classroom of other students who are watching you, and are also relying on you to maintain order and peace. If you get angry, you will be seen as someone who is not in charge anymore. You don't want that. You need to maintain professionalism. Do not get lowered to the student's level.
This also means not raising your voice. A yelling and screaming teacher is seen as an out of control teacher. Again, if you seem out of control, the whole class can dip into chaos. You speaking in a calm, but firm voice, can do wonders at least to diffuse the situation. Yelling will never solve anything. Maintain your cool at all cost.
Other students in your classroom may feel emboldened to get in on the action. They may want to be on either side. They see the teacher as someone who may need protecting. Do not allow any student to get involved. You will only escalate the situation. Now instead of just one student, you may have several to deal with. You cannot do this.
Your goal as a teacher with a confrontational student is to lower the steam. Even if it is just until the bell rings. Most of the time a few stern, calm words can lessen the tension for at least the last minutes of class. That's your goal. To make it to the end, then contact the principal about what happened.
If you have a chance, you may wish to talk to the student alone, after class. Not alone in the classroom, but in full view in the hall or school yard. Talk like two adults. This can actually work very well.
Writing a detention or office referral does not really work. Most of the time, the kids just get lip service and are right back. In fact, I believe this is counterproductive. It becomes a game. You kick the student out, they come back, repeat. They will wear you down before they wear you down.
A call home may not help either if you have never called home before. Calling home the first time for a behavior problem is crazy. The parent has every right to wonder where you have been. Telephoning home can be a powerful tool. But you need to call home to every parent at least once or twice the first week of school. This alone will put parents and students on notice that you are going to have them be an active party. Make it an ongoing effort.
One caution. Teachers are not police. If a student is really getting out of hand, you need to make the judgment that you need help. Call the office immediately.