Mandibular Third Molars in Southern Bulgaria – A Clinical and Radiological Study of 1518 Patients

Results: From 1518 patients, 851 were females, 667 were males. The mean age of patients was 45.31 years with a standard deviation of 15.64 years. The largest part of the third mandibular molars were properly erupted 28.43% /863 teeth/ from all studied teeth. The incidence of impaction of mandibular third molars was 18.74% /569 teeth/. The frequency of semiimpacted mandibular third molars was 7.48% /227 teeth/. From both impacted and semiimpacted teeth, 46.86% /373 teeth 245 impacted and 128 semiimpacted/ show mesioangular impaction. The next most frequent position was vertical – 29.4% /234 teeth, from which 178 were impacted, and 56 were semiimpacted/. Horizontal was position of 92 impacted and semiimpacted mandibular third molars /11.56%/, 76 teeth /9.56%/ show distoangular impaction, 15 teeth /1.88%/ were positioned buccolingually, 6 teeth /0.75%/ were classifi ed as other than mentioned position. The frequency of agenesis of the mandibular third molars was 6.69% /203 missing buds/. The cases of standard extraction of mandibular third molars, representing 25.69% /780 teeth/. Surgical removal of mandibular third molars was observed in 12.65% /384 teeth/. Research Article


Introduction
Third molars are the only teeth in the human dentition without strictly specifi ed time for their eruption. The normal eruption time of third molar is after 16 years of age [1].
According Favre ,et al. [2]. Impacted teeth are classically defi ned as retained in the jaw beyond their normal date of eruption, surrounded by their coronary bag and without communication with the oral cavity. Hashemipour, et al. [3]. Defi ned tooth impaction as a pathological situation in which a tooth cannot or will not erupt into its normal functioning position.
The aim of this study was to evaluate mandibular third molars.

Material and Methods
The objects of evaluation were 1518 dental patients visited two dental practices in Plovdiv, Bulgaria in the period between May 2013 and May 2016. A clinical, radiographic and questionnaire study was performed. The presence and position of the left and right mandibular third molar, and the type of performed extraction was investigated (3036 records).   (Table 4).

Discussion
The possible time limit for the formation of the third molar germ is 13 years [4]. Third molars erupt between 17 and 21 years of age [5]. Difference in time for eruption of the third molars    between different races exist [6]. Our study included patients over 17 years, which coincides with the recommendations given in the literature [7], and established facts -jaws grow and reach their basic size in the age to 17 years, which means that 17 years is the minimum age at which can to assess whether a mandibular third molar will erupt or remain impacted into the jaw.
Third molars impaction is more common in the mandible and varies between 16.7% and 68.6% in different studies [8].
Quek, et al. [12], found 63% bilateral impaction of third molars. Hashemipour, et al. [3]. Found no statistically signifi cant differences between impacted third molars in the right and left mandibular side. Deshpande, et al. [17], reported a higher incidence of impacted right mandibular molars -58.8%, which is consistent with our fi ndings of low prevalence impaction of the right mandibular third molars.
Data from our study show that the impaction of mandibular third molars is most common in the second and third decade of life, which coincides with the fi ndings of Osborn, et al. [18], Hashemipour, et al. [3], found that more than half of patients with impacted third molars are in the third decade of life. The majority of authors who study the problem of the mandibular third molars impaction established predominantly affecting the young patients [9,16].
Mandibular third molars in males erupted three to six months earlier compared with females [19], in the literature prevailing conception that cases of mandibular third molars

Conclusion
The mandibular third molar is the only tooth that is unpredictable in his form, position and time of eruption. The impaction of mandibular third molars is common phenomenon. In the present study, 18.74% of patients had impacted teeth, 7.48% had semiimpacted mandibular third molars. The prevalence of impacted third molars in female was more than male. The frequency of agenesis of the mandibular third molars was 6.69%.