| Objective: To investigate the appearance, location and morphology of mandibular lingual foramina(MLF) in the Chinese Han population using cone beam computed tomography(CBCT). In order to make a detailed operation plan to reduce the occurrence of complications during and after oral operation. And improving the success rate of oral surgery, such as endodontic surgery, oral implant surgery,mandibular bone harvesting surgery and mandibular bone distraction surgery.Methods: A total of 200 subjects(103 female subjects, 97 males, age range 10-70 years, with a median age of 27) of Southwest Medical University Affiliated Stomatological hospital were retrospectively analysed to identify MLF. The CBCT scan were taken from June 2012 to July 2014 to investigating conditions of the oral and maxillofacial regions of the subjects. The whole mandible were observed to locate and measure the dimensions of lingual foramina. The number, location and direction of the lingual canal were recorded for analyse. In addition, linear measurements were performed to describe the characteristics of the lingual foramina, including the diameter of the lingual foramina(D), the vertical distance between the lingual foramina and the alveolar ridge crest(L1), the vertical distance between the lingual foramina and the tooth apex(L2), and the vertical distance from the mandibular border to the lingual foramina(L3). The differences between men and women in the diameter, the vertical distance between the lingual foramina and the alveolar ridge crest(L1), the distance between the lingual foramina and the tooth apex(L2), and the distance from the mandibular border to the lingual foramina(L3) were also analysed. The subjects were divided into three age groups: 10-19, 20-49, 50 years and above to compare the difference in the measurements of D, L1, L2 and L3 in the three age groups.Results: CBCT can clearly display the anatomy of the lingual foramina. In this retrospective study, 683 lingual foramina were detected in 200 CBCT scans. 99.5% of the subjects were presented with lingual foramina and only one had no lingual foramina in the whole mandible. The number of lingual foramina in the mandible ranged from 0 to 8 in an individual, and most subjects had 3(24.50%, 49/200) or 4(23.50%, 47/200) lingual foramina.139 subjects had only median lingual canal(MLC), 3 had only lateral lingual canal(LLC), 57 had both. The incidence rate of MLC was 98%, and LLC was 30%. Among the 683 identified foramina, 538(78.77%) were ?1mm and 145(21.23%) were >1mm. Among all the lingual canals 85.07% were MLC and 14.93% were LLC. In relation to the tooth apex, we found two typical lingual foramina: foramina above the tooth apex and below the tooth apex. Most foramina(74.08%) were below the tooth apex and the rest(25.92%) were above the tooth apex. The mean diameter of the lingual foramina above the tooth apex was 0.74±0.26 mm and below was 0.88±0.33 mm. The mean diameter of the lingual foramina above the tooth apex was smaller than that of the below one(p<0.05). Males had statistically larger lingual foramina in the MLC than females(p<0.05).The L2 values changed with increasing of the age. In the lingual foramina above the tooth apex the value of L2 in the 10-19(group A), 20-49(group B) and above 50 years(group C) was 7.17±1.96 mm, 5.44±2.26 mm and 4.03±2.31 mm respectively, A>B>C and the difference was of statistically significance(p<0.05). In the lingual foramina below the tooth apex, the value of L2 in the three age groups was 9.55±5.02 mm, 11.48±4.89 mm and 12.91±4.95 mm respectively, A<B<C and the difference was statistically significant(p<0.05).Conclusions: CBCT can clearly display the lingual foramina with their three-dimensional structures, positions, courses and relationship with adjacent anatomic structures. Take CBCT scan before implant surgery, bone grafting surgery and endodontic surgery is important to reduce surgical complications. Careful oral surgery planning is even more necessary in male or elderly patients because of the structural characteristics of their lingual foramina. |
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