Can you tell me is having only one front tooth rare?

Yes: What do you mean by only one front tooth? Picture would help. If your talking about a person missing one of the front central incisors, i would say its rare.

Depends on tooth: Upper lateral incisors, the teeth on either side of the middle teeth, are often (about 20%) misshapen or missing. Missing upper central incisor is extremely rare and x-ray needed to make sure it isn't impacted. Missing lower incisor unusual, but not as rare as missing upper central. Have a complete examination, including x-rays, at your dentist's office. There may be other missing teeth.