# The Presence of Impacted Teeth (Except for Wisdom Teeth) in Orthodontic Patients in Israel
## 4 Discussion  
In this study, we examined data on the presence and distribution of impacted teeth in orthodontic patients in Israel. It was found that the prevalence of impacted teeth in orthodontic patients is 11.9% (95% confidence interval: 10.35-13.47%). This prevalence is higher than reported in other studies, being up to 6.15% of the population [2; 19]. It probably represents the population of patients referred for treatment within a university/hospital setting and is less suitable for describing the general population, since in many cases the complex cases fall within the university framework. In an attempt to find an epidemiological link and understand the family genetics of impacted teeth, the groups were compared with respect to a number of variables, some with significant results and some with a tendency to significant results. Examining patients' birth data, we found that the mean week of birth in the study group (38.7 weeks) was earlier than the week of birth in the control group (39.36 weeks) and the results were almost significant, even though the clinical significance is doubtful. In addition, we found significant tendency regarding the nature of birth, with more cesarean sections in the study group compared to the control group. These results are consistent with the hypothesis that a preterm birth week can affect the presence of impacted teeth, and accordingly are consistent with other studies in which the connection between preterm births and the need for complex orthodontic treatment has been proven, including impacted teeth [13]. A possible explanation for this phenomenon may lie in the fact that infants born in the week of pregnancy earlier than normal have not yet completed their fetal development, especially when it comes to the respiratory system. Another explanation is related to iatrogenic damage that can be caused in the care of babies after birth, such as oxygen given to the baby through his nose affecting bone development [20]. A meta-analysis conducted in England examined the effects of cesarean delivery on infants and found an association between surgical birth and an increased risk of developing asthma in those children compared to children born by normal birth [20], which corresponds to the findings in the present study in which in the study group presented more systemic diseases related to the respiratory system. There are multiple causes for impacted teeth, such as systemic factors, local factors and genetic factors [3; 4; 5; 6]. The familial connection to impacted teeth and other dental anomalies has been investigated and proven in many studies [12], and significant results have been obtained in the present study as well. Among the study group, it was found that there were significantly more dental anomalies in the patient's family members, including impacted teeth. In addition, the study group had more dental anomalies in the patients themselves (with the impacted teeth), findings which are consistent with reports from previous studies that showed a correlation between impacted teeth and other dental anomalies [9]. In performing the logistic regression model, risk factors for the presence of impacted teeth were the only dental anomalies in the patients and in their family members with increased odds ratios of 5.7-fold and 6-fold, respectively, for the presence of an impacted tooth, which is consistent other studies [4; 5; 21]. Previous studies have also reported the association between impacted teeth and lack of wisdom teeth [10; 11], but in the present study we have not been able to prove this association, probably due to limited sample size. Other differences found between the groups were related to the treatment referee and the chief complaint of the patients. In the study group, most patients were referred by a community general dentist compared to the control group where high percentages of patients came independently.