|Year : 2016 | Volume
| Issue : 3 | Page : 45-49
Prevalence and characteristics of impacted permanent molars in a Turkish subpopulation
Elif Yildizer Keris1, Süleyman Bozkaya2, Mustafa Öztürk1, Kahraman Güngör3
1 Department of Dentomaxillofacial Radiology, Çanakkale Dentistry Hospital, Çanakkale, Turkey
2 Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Gazi University, Ankara, Turkey
3 Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Gazi University, Ankara, Turkey
|Date of Web Publication||21-Dec-2016|
Elif Yildizer Keris
Department of Dentomaxillofacial Radiology, Çanakkale Dentistry Hospital, Çanakkale
Source of Support: None, Conflict of Interest: None
Background: The aim of the present study was to evaluate the prevalence and characteristics of impacted permanent molars in a Turkish subpopulation. Materials and Methods: A total of 45816 panoramic radiographs of patients aged more than 13 years were examined retrospectively to determine the presence, number, location, position, and related complications. The patients' age and sex were noted. During statistical analysis, descriptive statistics and cross-tabulations, Chi-square test, and Fisher's exact were used. The P value was set at 0.05. Results: The prevalence of impacted permanent molars was found to be 0.18% in this population. In total, 109 impacted first/second molars were observed in 83 patients, 18 cases had two or more impacted permanent molars. Impacted first/second molars were observed significantly more frequently in male patients than in female patients (P < 0.05). Mandible was a more common region of impaction (P < 0.05) whereas there was no significant difference between the left and right sides (P > 0.05). According to the position of the impacted permanent molars, 58 were detected as vertical direction, 28 were impacted as mesioangular, 12 were impacted as distoangular, 9 were impacted as horizontal, and 2 were impacted as buccolingual direction. In this study, cystic changes related to impacted teeth were observed in 14 (12.9%) cases and root resorption, carious lesion of the neighboring teeth were uncommon, our findings showed that majority of impacted first/second molars were found to be asymptomatic. Conclusions: Early diagnosis and treatment of eruption disturbances may avoid impaction in complicated orthodontic treatment.
Keywords: Impacted first molar, impacted second molar, prevalence
|How to cite this article:|
Keris EY, Bozkaya S, Öztürk M, Güngör K. Prevalence and characteristics of impacted permanent molars in a Turkish subpopulation. J Oral Maxillofac Radiol 2016;4:45-9
|How to cite this URL:|
Keris EY, Bozkaya S, Öztürk M, Güngör K. Prevalence and characteristics of impacted permanent molars in a Turkish subpopulation. J Oral Maxillofac Radiol [serial online] 2016 [cited 2020 Dec 1];4:45-9. Available from: https://www.joomr.org/text.asp?2016/4/3/45/196345
| Introduction|| |
Tooth impaction is not a rare condition. Even though any tooth may be impacted, there is a tendency for impaction of third molars, maxillary canines, followed by second premolars. , Severe syndromes such as Cleido-cranial dysostosis and progeria; systemic diseases such as endocrine diseases or nutritional problems; local factors such as supernumerary tooth or an odontoma on eruption path, lack of space; or idiopathic factors are responsible for eruption disturbance. ,,,,,,,
Failure of eruption of the first and second permanent molars is uncommon.  There are limited data in the literature regarding eruption disturbances of the permanent molars. The incidence of retention/impaction of the lower permanent second molar has been reported to be 0.06-0.3%. ,, First and second permanent molars play an important in the development of dental and facial anatomical structures.  It has been reported that impaction of first or second permanent molars leads to retrognathia inferior.  Early diagnosis of and treatment of eruption disturbances may avoid impaction. In addition, in late stages of eruption, disturbances may require complicated orthodontic treatment. 
The aim of the present study was to evaluate the prevalence and characteristics of impacted permanent molars in a Turkish subpopulation.
| Materials and Methods|| |
Records of 45816 panoramic radiographs that were taken from patients who applied to Gazi University, Faculty of Dentistry, Department of Oral and Maxillofacial Radiology Services were examined retrospectively. Patients ≤12 years of age and who had any systemic diseases and syndromes were excluded. Patients who had undergone any extractions in the first and second molar area were also excluded. Patients' age and sex were noted. Their digital panoramic radiographs were examined to determine impacted permanent first or second molar teeth.
All teeth that appeared to be restricted due to eruption of bone or adjacent teeth were recorded as impacted. We investigated the prevalence, location, position, and number of impacted teeth. In addition, pathologic conditions and complications caused by impacted teeth were recorded. Pathologic conditions and complications caused by impacted teeth were classified as caries/resorption in neighboring teeth, cystic changes related to impacted teeth, and asymptomatic.
All evaluations were carried out by two specialists of Oral Diagnosis and Radiology, with at least 10 years of experience. All data were statistically analyzed using the Statistical Package for the Social Sciences version 18.0 (SPSS, Chicago, IL, USA) by using descriptive statistics and cross-tabulations. The Chi-square test or Fisher's exact test was performed to determine the statistical significance of differences in prevalence of findings between the sexes, between upper and lower jaws, and between the right and left sides of the patient. The P value was set at 0.05.
| Results|| |
Digital panoramic radiographs were observed in 45816 patients aged 13-60 years of age, including 20455 (44.7%) males and 25361 (55.3%) females [Table 1].
In total, 109 impacted first/second molars were observed in 83 patients, 18 cases (21.6%) had two or more impacted permanent molars, and 65 (78.4%) cases had one impacted permanent molar. Ninety-eight of 109 impacted permanent molars were second molars and 11 of the impacted permanent molars were first molars [Figure 1]. Prevalence of second molar impaction was 0.21%, and that of first molar impaction was 0.02%.
|Figure 1: Panoramic radiograph of a 32‑year‑old female patient showing impacted right mandibular first molar|
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Sixty-eight of the 98 impacted second molar teeth were located in the mandible (69.3%) and 30 in the maxilla (30.7%). There was a significant difference between jaws (Fisher's exact test, P = 0 < 0.05); mandible was a more common region of impaction. Forty-one of 68 mandibular impacted second molars were present in the right quadrant, and 27 were in the left quadrant. Thirteen of the 30 maxillary impacted second molars were present in the right quadrant and 17 were in the left quadrant. Seven of the 11 impacted first molar teeth were located in the mandible (63.6%) and four in the maxilla (36.4%). Six of the 7 (54.5%) mandibular impacted second molars were present in the right quadrant, and 1 (9.1%) was in the left quadrant. One of the 4 (9.1%) maxillary impacted second molars was present in the right quadrant, and 3 (27.3%) were in the left quadrant [Table 2]. There was no significant difference between the left and right sides (Fisher's exact test, P = 0.503456 > 0.05).
According to the position of the impacted permanent molars, 58 were detected as vertical direction (53.2%), 28 were impacted as mesioangular (25.72%), 12 were impacted as distoangular (11%), 9 were impacted as horizontal (8.25%), and 2 were impacted as buccolingual direction (1.83%). [Table 3] presents the distribution of impacted permanent molars position.
Cystic changes related to impacted teeth were observed in 14 (12.9%) cases [Figure 2]. Carious lesions in teeth which was adjacent to the impacted tooth were seen in only 4 cases (%3.6). Nine impacted permanent teeth caused resorption in the neighboring teeth (8.3%) [Figure 3]. Eighty-two (75.2%) of the impacted teeth were asymptomatic. [Table 4] presents the complications of impacted permanent molars.
|Figure 2: Cyst formation related to the impacted molars in the right mandibular region|
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|Figure 3: Impacted second molar caused resoption of the third molar in the left maxillary region|
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| Discussion|| |
There are differences in the eruption between permanent molars and other permanent teeth because permanent molars do not have preceding primary teeth.  Hence, permanent molars may be impacted. According to the literature, eruption problems of permanent molars is rare. ,, In this study, prevalence of impacted first/second molars was found to be 0.18%. Bereket et al.  investigated 104,408 panoramic radiographs of a Turkish subpopulation and reported that the incidence of impacted first/second molars was 0.19%, which is similar to our study.
With regard to the gender distrubitions, males were more affected than females. , Impacted first/second molars were observed significantly higher in male patients (0.25%) than that in female patients (0.12%) in this study. However, in contrast, female prediliction was described rarely.  Different results reported among studies may be related to the difference in investigated populations.
Most of the studies regarding prevalence of impacted permanent molars were focused on mandibular second molar impaction. There are limited data in published studies regarding the prevalence of impaction of first permanent molars. Prevalence of second molar impaction was found to be 0.21%, whereas first molar impaction was found to be 0.02% in this present study. First molar impaction is very rare; in a previous study by Dachi and Howell,  it was reported that only three impacted mandibular first molars were seen in 1218 impacted permanent molars. According to the literature, second molar impaction was detected to be 0.07-0.16% of the investigated populations. , Our results are in accordance with previous studies.
It has been declared that eruption problems of permanent molars occur more commonly in the mandible than in the maxilla and the rate of second molar impaction is higher than first molar. , In this study, the majority of the impacted molars were located in the mandible, and mandibular second molars were the most affected teeth (69.3%), which is in agreement with previous studies.
According to our results, more than half of the impacted teeth were detected as vertical direction (53.2%). In contrast, Varpio and Wellfelt  found that most of the impacted teeth were in a mesioangular position. The authors stated the cause of the vertical position may be attributed to ankylosing of teeth. However, Raghoebar et al.  declared that diagnosis of ankylosis can only be made by histological assessment and it cannot be detected by clinical examination.
Impacted teeth were often observed in an abnormal position, and hence, they may cause some complications such as root resorption, carious lesion of the neighboring teeth, and cystic changes. ,,, There is scarce information regarding the complications of impacted permanent molars. In this study, cystic changes related to impacted teeth were observed in 14 (12.9%) cases, and root resorption and carious lesion of the neighboring teeth were uncommon. Our findings showed that majority of impacted first/second molars were found to be asymptomatic, which is similar to other studies.  In general, impacted first/second molars are diagnosed during routine dental controls because of their asymptomatic nature. Early diagnosis and management of impacted permanent molars is important to inhibit more complicated cases. , Panoramic radiography usually used for initial radiographic examination in dentistry and is useful for diagnosis of impacted first/second molars.
It was suggested to observe impacted permanent molars for a year before treatment approaches because possible self-correction of impacted teeth should be eliminated.  Treatment choices vary according to the clinical and radiographical findings. The management of impacted first/second molars includes surgical and orthodontical approaches. The treatment options are orthodontic uprighting, surgical repositioning, extraction of the impacted second molar to allow the third molar to drift mesially, extraction of the impacted second molar, and transplant of the third molar into the extraction site. , The treatment options have some complications, and hence the decision of treatment choices should be made after a costs-benefit analysis for each patient.
| Conclusion|| |
In the present study, we evaluated impacted permanent molars on panoramic radiographs. The prevalence of impacted permanent molars was found to be 0.18% in this population. Impacted first/second molars were observed more frequently in male patients than that in female patients, and were more common in the mandible than in the maxilla. According to our results, more than half of the impacted teeth were detected as vertical direction (53.2%). In this study, cystic changes related to the impacted teeth were observed in 14 (12.9%) cases, and root resorption and carious lesion of the neighboring teeth were uncommon. Our findings showed that majority of impacted first/second molars were asymptomatic. More studies are needed to detect the prevalence of impacted permanent molars among different populations.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]
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