The objective of this investigation was to discover the actual conditions that cause delayed eruption teeth.
The investigation comprised 76 children (40 boys and 36 girls) who complained of delayed eruption of the permanent teeth at the Pediatric Dental Clinic in the Suidobashi Hospital, Tokyo Dental College from April 1989 through June 1995.
Observations were made concerning prevalence of delayed eruption teeth, the causes, the average age of patients at the beginning of treatment, and the treatment itself.
The incidence of the delayed eruption teeth accounted for 7.2% of the new patients. There was no difference according to sex.
The total number of the delayed eruption teeth was 95. The causes of the delayed eruption teeth in the maxilla most often were abnormal position of the tooth germ, followed by an apparent fibrous barrier, supernumerary teeth, retarded exfoliation of the predecessor teeth, effects of dental trauma to deciduous teeth, lack of space for eruption, follicular cysts, odontoma, in that order. In the mandible, the causes were only abnormal position of tooth germ or follicular cysts.
Exposure of the crown from the alveolar bone and active eruptions were more common than exposing of the crown from gingiva.
Three teeth were extracted. The upper central incisor with severe vestibular root angulation was such that it was decided to remove the tooth. The upper central incisor and canine showed odontoma and it was decided to remove the teeth. There were few extractions.