Investigating the Relationship between the Type of Impaction of Mandibular Third Molars and the Caries of Distal Surface of Mandibular Second Molars

Document Type : Original Article


1 Assistant Professor of Oral and Maxillofacial Surgery.Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

2 Assistant Professor of Oral Radiology.Department of Radiology, Faculty of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

3 Dentist.


Background and Objective: The impacted tooth is trapped tooth by an obstruction on the budding path. The existence of impacted mandibular third molar leads to increase of in the caries in the distal neck of second molar due to the contact of third molar.
Subjects and Methods: This study was analytical cross-sectional study conducted from May 2014 to March 2015 among 50 patients with mandibular third molar impaction. Panoramic X-rays and Bitewing radiograph was taken to determine the impaction types and the presence or absence of the second molar caries. Chi-square test was used to investigate the relationship between the mandibular third molar impaction and mandibular second molar distal surface caries.  Data were analysis by SPSS software version 18. PResults: The most common type of dental impaction was the mesioangular (34%). Distoangular and horizontal was (24%) while the vertical impaction was (18%). The degree of impaction in class II (80%) and for class III (20%) were recorded. According to the classification of Pell and Gregory, classes B was classified as the most prevalent impaction, and class A was the lowest. The prevalence of caries was reported in 52% cases. 38.48% cases of caries belonged to mesioangular impaction form which was significantly higher than other types (P<0.05).
Conclusion: Our study showed that the angle of impaction (mesioangular and horizontal) and the class II had significant correlation with caries.


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