Correlation of Acute Pericoronitis and Position of Impacted Mandibular Third Molar

Objective:To study the relationship between the characteristics of mandibular third molar position and incidence of pericoronitis.Methods:A total of 122(aged 18～31 years old) patients with acute mandibular third-molar pericoronitis were subjected into this study.Variables including the percentage of soft tissue coverage,occlusal trauma of maxillary dentition,the angulation and eruption level of the mandibular third molar were recorded.The data was statistically analyzed.Results:Vertical impaction was the most frequent angulation(57%),mesioangular impaction(34%) was higher than horizontal impaction(7%),and distoangular impaction was quite rare(2%).Difference between type of angulation was statistically significant for all groups(P0.05).The frequency of partial soft tissue coverage,particularly 75%coverage,was much more observed than the full soft tissue coverage.The difference for the amount of soft tissue coverage was statistically significant(P0.05).Occlusal trauma of maxillary dentition did not have a statistically significant(P0.05).Most pericoronitis (49%) was associated with the third molars that erupted at the same level of the adjacent tooth occlusal plane.The differences among the three levels of eruption were significant(P0.05).Conclusion:Impacted mandibular third molars with partial soft tissue coverage,exhibiting vertical inclination,reach or near to the level of the occlusal plane of the arch were considered with highest risk for developing pericoronitis.Such third molars should be given high priority for prophylactic care.