Patterns of intra-osseous transmigration and ectopic eruption of mandibular canines: review of literature and report of nine additional cases.

OBJECTIVES

The purpose of this study is to (1). investigate the patterns of transmigration and eruption of permanent mandibular canines, plus the mechanisms affecting the eruption path, (2). classify the transmigration paths.

MATERIAL AND METHODS

:A retrospective radiographic study using full mouth (FMX) and panoramic radiographs of dental radiology patients between July 1996 and July 2000. Transmigrated canines were identified from the radiographic records of 2150 new patients. The literature was reviewed regarding the individual patterns of canine transmigration and their final position within the mandible. A pattern classification was developed using literature data and the additional nine cases reported here.

RESULTS

In the present study, mandibular canines were found transmigrated on nine occasions and, in a further six cases, found impacted without transmigration. Out of the nine cases, seven were female (ages 17-38) and two were male (ages 20 and 69). One female patient had a bilateral transmigration of the mandibular canines. A total of 127 transmigrated canines were reported in 50 published studies from the literature. Transmigrated canines appear to fall into five patterns (Type 1-5) depending on their path of deviation. Type 1 was most common (45.6%) followed by Type 2 (20%), Type 4(17%), Type 3(14%) and Type 5 (1.5%).

CONCLUSIONS

Patterns of mandibular canine transmigration can be classified into five distinct patterns. The majority of cases demonstrated Type 1 transmigratory pattern. No clear aetiology of this disorder could be found.