Predictive factors of ectopic eruption of the maxillary permanent second molar: A retrospective study

Aim of the study: The aim of this study was to investigate the diagnostic methods and possible predictive factors associated
with maxillary second molars ectopic eruption.
Materials and Methods: This retrospective study assessed the diagnostic records of 40 adult female subjects (study models,
panoramic radiographs, and lateral cephalometric radiographs) equally divided into two groups: normal maxillary second molar
eruption (20 subjects, mean age 25.625.19±) and bilateral ectopic maxillary second molar eruption (20 subjects, mean age
27.784.65±). The variables were statistically analyzed by independent t-tests and Mann-Whitney U test.
Results: The mesiodistal diameter of the maxillary second premolars, first permanent molars and second permanent molars
bilaterally were significantly larger in the ectopic eruption group compared to the normal group. Greater arch lengths were also
recorded for the ectopic group. Regarding cephalometric measurements angles SNA, OP-17, and linear measurements PTV-16
and PTV-17 were significantly smaller in the ectopic eruption group. Angles HRL/16d-17d & Angle 1617- were significantly
larger in the ectopic eruption group. Panoramic radiograph in the ectopic eruption group showed increased inclination of the
maxillary molars in a distal direction compared to the normal eruption group whereby angles OP/17, OP/27 were significantly
smaller in the ectopic group. Intermolar angles 1617/ and 2627/ were significantly larger in the ectopic eruption group.
Conclusion: Multiple factors are associated with the ectopic eruption of maxillary second molars. This could be used as a
diagnostic aid for the prediction of this eruption disturbance.