Introduction: Detection of impacted teeth by the orthodontist is imperative for diagnosis and treatment planning. A tooth is impacted when it has arrested eruption due to the presence of a clinically or radiographically visible physical barrier in the path of eruption. The most commonly impacted teeth are third molars, followed by maxillary canines and mandibular second premolars. When referring to mandibular second molar (MM2) impaction, prevalence ranges from as low as 0.06-0.65%1-5, to as high as 1.36% and 1.8%. Numerous studies have identified etiologic risk factors for MM2 impaction, such as mesial crown angulation, dental crowding, morphological tooth anomalies, and a smaller distance between the mandibular first molar and the mandibular ramus.4-8 Studies also suggest a positive correlation between vertically directed condylar growth and impaction rates of mandibular second and third molars. However, to this day, few studies have correctly used lateral cephalograms to evaluate the skeletal morphology of the mandible and its relationship mandibular second molar impaction.5,9 Thus, the goal of this research study was to evaluate if there is a relationship between MM2 impaction and Class II malocclusions. Methods: In this retrospective study, 75 subjects with impaction of MM2 were compared to a control group of 200 subjects with normal eruption of MM2. Based on evaluation of panoramic x-rays, MM2 was classified as impacted if its complete eruption to occlusal plane height was prevented by an abnormal contact with another tooth in the same arch, and when it remained unerupted beyond ¾ root formation. The corresponding lateral cephalograms were then traced and analyzed using Dolphin Imaging Software available in the Nova Southeastern University Post-Graduate Orthodontic Clinic. Frequencies and percentages were calculated for all categorical variables, and means and standard deviations were calculated for continuous measures. Wilcoxon-Mann-Whitney-U-tests was used for statistical comparisons between groups, and a logistic regression model was used to examine the relationship between various independent variables and the presence of impaction. Results: No association was found between gender, age, and mandibular second molar (MM2) impaction. The sagittal analysis showed that MM2 impaction was more commonly seen in skeletal Class II patients (p
| Date of Award | Jan 1 2018 |
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| Original language | English |
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| Supervisor | Abraham B Lifshitz (Supervisor), Sergio Real (Advisor) & Gisela Contasti Bocco (Advisor) |
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