Pattern of Mandibular Third Molar Presentation: Ten Years Experience at the University College Hospital, Ibadan
Received Date: Oct 18, 2018 / Accepted Date: Oct 22, 2018 / Published Date: Oct 26, 2018
Background: Tooth impaction occurs when a tooth fails to erupt or develop in its proper functional location. The third molar is said to be the most commonly impacted tooth in the oral cavity and accounts for 98% of all impactions and mandibular third molars are the most frequently impacted.
Aim: The purpose of this study was to review 10 years pattern of presentation of mandibular the third molar impaction seen at the University College Hospital in Ibadan.
Material and Methods: A total of 597 impacted third molar teeth were reviewed. The angulations of impacted third molar teeth according to Winter’s classifications were recorded as documented in the patient’s case note. The cause of extraction such as pericoronitis, caries, other pathology, and orthodontic reason and second molar pathology were noted and recorded for every patient. Distributions of obtained values were compared using the Pearson χ2 test.
Results: The mean age of the subjects was 27.7 (range: 19-50); in a review of the 597 impacted third molar teeth, the most common angulation of impaction was mesioangular (320;53.6%) and pericoronitis (514;86.2%) was found to be the most common reason for disimpaction. Among 597 patients (244 males, 353 females), pericoronitis was more prevalent in females (101;30%).
Conclusion: The pattern of third molar impaction in UCH population was characterized by mesioangular impaction and was more common in females than males. Pericoronitis was the most common symptoms usually associated with level tooth impaction.
Keywords: Review; Pattern; Third molar; Impaction
Tooth impaction is a failure of a tooth to erupt to the normal functional position within the expected time; due to lack of space, or physical barriers . Teeth are said to be impacted when they fail to erupt or develop in their proper functional location .
Inadequate space in the mandible, among other factors, is the cause of third molar impaction .
There is a substantial variation in the frequency of third molar impaction amongst different populations; and these range between 18% and 70% [6-10]. This is attributed to racial variation in facial growth, jaw and tooth size .
Different classification systems have been used to describe impacted third molars, these are Winter’s  classification system which describe the angle formed between the intersected longitudinal axes of the second and third molars,  the Pell and Gregory  classification system which assess the level of third molar impaction where the impacted third molars are assessed in relation to the neighboring second molars .
Studies have reported different prevalence for impaction of the mandibular third molars and this varies between 16.7% and 68.6% [15-21]. Most studies available did not find a gender predilection; however, some studies have mentioned a higher incidence of impaction in females when compared to males [15,16,22].
The aim of the present study is to evaluate the pattern of third molar impaction in patients seen in the University College Hospital (UCH) within 10 years in terms of age, gender, angulations of impaction as recorded in the day book and the patients case note, furthermore, cross tabulation between patterns of impaction and gender was evaluated for any significant difference.
Materials and Methods
This study was undertaken on a group of patients who presented at the exodontias clinic of Oral and Maxillofacial Surgery UCH between January 2007 and December 2016.
A total of 597 patients who had impacted the third molar extracted were included in the study. The data required for each patient were collected retrospectively: Age, Gender, Type of impaction based on angulations and the quadrant where the impacted tooth is located were extracted from their records in the case note and oral and maxillofacial daily record book.
Due to the nature of the study (retrospective study), informed consent could not be obtained from the patients.
Data analysis was completed using SPSS 23.0 software (SPSS Inc., Chicago, IL). Statistical tests carried out included Pearson’s chi-square and Student’s t-test. A P-value less than 0.05 was considered statistically significant. All information gathered was carried out by two examiners to avoid the error of omission.
The total number of 611 patients who had impacted mandibular third molar extraction done between January 2007 and December 2016 were reviewed but only 597 who had complete information were eventually included in the analysis, 14 patient were not included due to insufficient information and each patient had one mandibular third molar disimpaction done, with a total of 597 third molars that were reviewed and included in the study. The sample consisted of 244 (40.9%) male and 353 (59.1%) female (Table 1) with age ranged from 18 to 50 and mean of 27.7 with female having more third molar extraction done more than male and the difference between male and female was statistically significant ( X2=16.7 and P Value=0.002) (Table 2).
|Gender||Impaction mesioangular||Distoanguler||Horizontal||Vertical||Transverse||Total x2 P value|
|Total||320(100)||80(100)||132(100)||63(100)||2(100)||597 (100) 16.72 0.002|
Table 1: Gender distribution.
|Agee||Mesioangular||Distoangular||Horizontal||Vertical||Transverse||Total x2 P value|
|Total||320(100.0)||80(100.0)||132(100.0)||63(100.0)||2(100.0)||597(100.0) - 0.0001|
Table 2: Age distribution.
Most patients were recorded in 2011 and the least was recorded in 2014. Six-five were recorded in 2007, 59 in 2008, 53 in 2009, 48 in 2010, 72 in 2011, 49 in 2012, 70 in 2013, 44 in 2014, 66 in 2015, 71 in 2017 with average of 59.7.
The highest pattern for impacted teeth was mesioangular 320 (53.6%) impaction and lowest was transverse 2 (0.3%) (Tables 1-4).
Most third molar extraction that was done in this study was in the third decade where 405 (67.9%) cases were recorded followed by the fourth decade, a second decade and fifth decade, the difference was statistically significant with X2 =274.89 and P Value=0.0001 (Table 2).
More third molar extractions were done on the left than the right mandible with a statistically significant difference (X2=16.61, P Value=0.00158) (Table 3).
|Quadrant||Mesioangular||Distoanguler||Horizontal||Vertical||Transverse||Total x2 P value|
|Right||112 (35.0)||32 (40.0)||61(46.2)||22 (34.9)||0(0.0)||227(38.0)|
|Left||208 (65.0)||48 (60.0)||71(53.8)||41 (65.1)||2(100.0)||370(62.0)|
|Total||320 (100)||80(100)||132(100)||63(100)||2(100)||597 (100) 16.61 0.00158|
Table 3: The affected quadrant.
There is no different between male and female in the distribution of impacted teeth on the right quadrants (X2=13.06, P Value=0.005) while there is a statistically significantly different between male and female in the distribution of impacted teeth on the left quadrant especially the mesioangular impaction with (X2=24.04 13.06, P Value=0.0001) (Table 4).
Table 4: Quadrant, gender, and type of impaction tabulation.
Recurrent pericoronitis 525 (85.3%) was the main cause for extraction followed by caries (Table 5).
|Gender||Pericoronitis||Caries||Other pathology||Orthodontic reason||2nd Molar Pathology||Total|
Table 5: Associated pathology.
The majority of patients in this study were Yoruba tribes between the Age of 18 and 50 years. In this study, we found that the incidence of mandibular third molar impaction was significantly higher in females when compared with males. This finding is in agreement with the findings in the literature [8,9,15,20]. The higher incidence in women has been attributed to the fact that the physical growth in women usually stops earlier than men leading to a smaller jaw size [8,9]. Also, the initiation of third molar eruption in women is said to occur after the growth of the jaw is completed unlike in men whose jaw growth continues during the third molar eruption and thus provides more space for the tooth .
More third molar extractions were done on the left than the right mandible with a statistically significant difference. There is no difference between male and female in the distribution of impacted teeth on the right quadrants while there is a statistically significantly different between males and females in the distribution of impacted teeth on the left quadrant especially the mesioangular disimpaction.
In the present study, the most common type of angulation of impacted mandibular third molar was mesioangular, followed by horizontal, distoangular, vertical and transverse being the least. The findings are similar to those of Eshghpour et al. . It is also similar to that of Hashemipour et al  who found that mesioangular impaction was the most prevalent type of impaction in the mandibular third molars of African American, Singaporean, American, Arabian, and Iranian populations, respectively.
Most third molar extraction that was done in this study was in the third decade where 405 (67.9%) cases were recorded followed by the fourth decade, a second decade and fifth decade. This is in agreement with the findings in the literature [24,25].
In this study, we found that pericoronitis is the main reason for impacted mandibular third molar disimpaction. The findings are similar to those of Jamileh and Pedlar  et al. and Khawaja . There was a tendency in female patients for pericoronitis, but other symptoms showed no gender predominance. This finding is similar to those of Bataineh et al.  and Yamalık and Bozkaya et al. . However, Almendros-Marqués et al.  and Akarslan and Kocabay et al.  found no gender predominance for all complaints and pathologies. While Yilmaz et al.  reported male predominance.
Prajapati, et al.  in their study, recorded caries (especially of the adjacent tooth) and its sequelae as the major reason (63.2%) for the mandibular third molar extraction, followed by recurrent pericoronitis (26.3%) and periodontitis (9.2%) . Allen et al.  reported the incidence of 42% of the distal second molar caries associated with partially or completely impacted mandibular third molars .
Impacted teeth are commoner in females than males and in the left side than the right. Mesioangular impaction is the most occurred of all impaction and also commoner on the left side than on the right. This is true for all the years put together and also from an individual year and more in the third decade of life.
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Citation: Adelusi EA, Okoje VN (2018) Pattern of Mandibular Third Molar Presentation: Ten Years Experience at the University College Hospital, Ibadan. Dentistry 8: 516. DOI: 10.4172/2161-1122.1000516
Copyright: © 2018 Adelusi EA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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