These are problems of the mouth of different degree of difficulty and of complication that are categorized as:
1. Orthodontic problems
These refer to teeth problems concerning the position, the number, the size etc. of teeth.
2. Orthognathic problems
These refer to problems concerning the jaws (the mandible and the maxilla), their size and their position.
3. Functional problems
These refer to problems concerning the function of the stomato-gnathic system in relation to a good functional relationship between the two jaws.
4. Complex problems
These refer to several combinations of the above mentioned problems. They occur when minor non-diagnosed problems have developed and become complicated and risk ending up as complex and severe.