• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.3
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• pp.158-166
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• 2019

Objectives: Inferior alveolar nerve block (IANB) is the most frequently used treatment for mandibular molars. Successful IANB requires insertion of the dental needle near the mandibular foramen. In this study, we aimed to analyze the anatomic location of the mandibular lingula and evaluate the effects of internal oblique ridge (IOR)-guided IANB. Materials and Methods: The location of the mandibular lingula was measured using cone-beam computed tomography images of the mandibles obtained from 125 patients. We measured the distances from the occlusal plane to the lingula and from the IOR to the lingula in 250 mandibular rami. Based on the mean of these distances, alternative anesthesia was carried out on 300 patients, and the success rate of the technique was evaluated. Results: The mean vertical distance was $8.85{\pm}2.59mm$, and the mean horizontal distance was $14.68{\pm}1.44mm$. The vertical (P<0.001) and the horizontal (P<0.05) distances showed significant differences between the sex groups. The success rate of the IOR-guided technique was 97.3%. Conclusion: IANB-based location of mandibular lingula showed a high success rate. From this study, we concluded that analysis of the anatomic locations for mandibular lingula and IOR-guided IANB are useful for restorative and surgical dental procedures of the mandibular molars.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.125-132
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• 2020

Purpose: The positions of the mandibular foramen (MnF) and the lingula affect the success rate of inferior alveolar nerve block. The objective of this study was to investigate aspects of the MnF and the lingula relevant for mandibular block anesthesia using cone-beam computed tomography (CBCT). Materials and Methods: Fifty CBCT scans were collected from a picture archiving and communications system. All scans were taken using an Alphard Vega 3030 (Asahi Roentgen Co. Ltd., Kyoto, Japan). Fifty-eight MnFs of 30 subjects were included in the study. The position of the MnF, the size of the MnF, the position of the lingula, the size of the lingula, and the shape of the lingula were measured and recorded. All data were statistically analyzed at a significance level of P<0.05. Results: The position of MnF was 0.1 mm and 0.8 mm below the occlusal plane in males and females, respectively. The horizontal position of the MnF was slightly anterior to the center of the ramus in males and in the center in females (P<0.05). The vertical position of the MnF was lower in females than in males(P<0.05). The MnF was an oval shape with a longer anteroposterior dimension. The height of the lingula was 9.3 mm in males and 8.2 mm in females. The nodular type was the most common shape of the lingula, followed by the triangular, truncated, and assimilated types. Conclusion: CBCT provided useful information about the MnF and lingula. This information could improve the success rate of mandibular blocks.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.3
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• pp.370-375
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• 2008

Sagittal split ramus osteotomy (SSRO) is widely used in treatment of dentofacial deformities. But, many complications can occur including unfavorable fractures during osteotomy. To prevent these complications, it is necessary to understand comprehensively the anatomy of the mandiular ramus. The purpose of this study was to evaluate the morphology of the madibular ramus in manibular prognathism patients by computed tomography comparing with normal control group. The study group consisted of 33 skeletal class III patients (20 males, 13 females) and the control group consisted of the 52 patients without dentofacial deformities (32 males, 20 females). The mean age of study group was 22.0-year old, and that of control group was 37.1-year. For the CT examination, following scan parameters was used: 1mm slice thickness, 0.5 second scan time, 120kV and 100mA/s. The axial scans of the head were made parallel to the mandibular occlusal plane. The anteroposterior length of the ramus, the distance from anterior border of the ramus to lingula, the relative distance from the anterior border of the ramus to lingula compared to the anteroposterior length of the ramus, the thickness of anterior and posterior cortical plate, the thickness of medial cortical plate of the ramus at lingula level, the thickness of cancellous bone of the ramus at lingula level were measured. The skeletal class III mandibular prognathism patients exhibited shorter anteroposterior length of the ramus, thicker anterior and posterior cortical plate, thinner mediolateral cancellous bone thickness. The lingula has a relative stable anteroposterior position in ramus in all groups. There was higher possibility of fusion of medial and lateral cortical plate at lingula level in the mandibular prognathism group. In conclusion, the mandibular prognathism patients have narrow rami with scanty cancellous bone, which means that careful preoperative examination including CT scan can prevent undesirable fractures during osteotomy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.30.1-30.7
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• 2017

Background: The positions of the mandibular lingula and foramen have been set as indexes for inferior alveolar nerve (IAN) block and ramus osteotomies in orthognathic surgery. This study aimed to evaluate the anatomical structures of mandibular ramus, especially the mandibular lingula and foramen, by analyzing the cone-beam computed tomography (CBCT) data of young adults. Methods: We evaluated 121 sides of hemi-mandibular CBCT model of 106 patients (51 male and 55 female patients; 18 to 36 years old). All the measurements were performed using the 2- and 3-dimensional rulers of $OnDemand3D^{(R)}$ software. Results: Statistical analysis of the data revealed that there was no significant difference in the mandibular angle between the genders. The mandibular lingula was found to be located at the center of ramus in males, but a little posterior in relation to the center in females. The mandibular lingula was rarely located below the occlusal plane; however, the position of the mandibular foramen was more variable (84.3% below, 12.4% above, and 3.3% at the level of the occlusal plane). Conclusions: The results of this study provide a valuable guideline for IAN block anesthesia and orthognathic surgery. CBCT can be considered effective and accurate in evaluating the fine structures of the mandible.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.15.1-15.6
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• 2018

Background: The purpose of this study was to identify the location of the antilingula, lingula, and mandibular foramen in Korean cadavers and to promote safe and accurate surgery without damage to the inferior alveolar neurovascular bundle (IANB) when performing a vertical ramus osteotomy (VRO). Methods: This study was conducted on the dried mandibles of 20 adult cadavers. Digital calipers were used to measure the distances from the anatomical reference points (antilingula, lingula, and mandibular foramen). Result: The antilingula was located at the anterior 44% and superior 31% in the ramus. The lingula was located at the anterior 55% and superior 30% in the ramus. The mandibular foramen was located at the anterior 58% and superior 46% in the ramus. Regarding the positional relationship with the antilingula, the lingula was located 0.54 mm superior and 4.19 mm posterior, and the mandibular foramen was located 6.95 mm inferior and 4.98 mm posterior. The results suggested that in order to prevent damage to the IANB, osteotomy should be performed in the posterior region of ramus at least 29% of the total horizontal length of the ramus. Conclusion: Using only the antilingula as a reference point is not guaranteed to IANB injury. However, it is still important as a helpful reference point for the surgeon in the surgical field.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.64-76
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• 2021

The purpose of this study is to evaluate the position of the mandibular foramen and location and morphological characteristics of the mandibular lingula using Cone-Beam Computed Tomography (CBCT). Mandibular CBCT images of children aged 6 - 16 years were collected. A total of 180 patients were divided into 3 groups, 6 - 7, 10 - 11 and 15 - 16 years, with 30 male and female patients per group. Either side of the ramus was analyzed. The shortest distances from the anterior, posterior, superior and inferior border of the ramus to the mandibular lingula were measured. The shortest distance between the mandibular lingula and the mandibular foramen was also measured. The vertical distance from the mandibular lingula and the mandibular foramen to the occlusal plane was measured. The shapes of the mandibular lingula was classified into 4 types according to the criteria. The distances of the mandibular lingula from the anteroposterior and vertical reference points of the ramus increased in all directions with age. The distance between the mandibular lingula and the mandibular foramen also increased with age. The location of the mandibular lingula and the mandibular foramen in relation to the occlusal plane moved upwards with age. The most common shape of the mandibular lingula was triangular, followed by nodular, truncated and assimilated, and there was no difference in the shape according to age. It is recommended that the horizontal insertion point of the anesthesia from the anterior border of the ramus increased to 17 mm, 18 mm, and 19 mm according to the age groups. It is also suggested that the vertical insertion point increased by 2 - 3 mm, 5 - 6 mm and 9 - 10 mm above the occlusal plane according to the age groups.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.2
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• pp.126-131
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• 2002

Anatomical shape of the mandibular ramus, which includes the area from the rear of the mandibular second molar to the mandibular posterior border and from the mandibular sigmoid notch to the inferior mandibular border, must be carefully considered to perform orthognathic surgery. The locations of the lingula and mandibular foramen in medial side of mandibular ramus are one of the most important factors to decide the location of the horizontal medial osteotomy in sagittal split ramus osteotomy and to select the line of vertical osteotomy in intraoral vertical ramus osteotomy. Sixty-five different Korean human dry mandibles were surveyed. All mandible have permanent dentition including complete eruption of the mandibular second molar. The locations of the lingula and mandibular foramen in medial side of the ramus were identified and following results were obtained. Anterior ramal horizontal distance from lingula was $16.13{\pm}3.53mm(range:8.6{\sim}24.3mm)$, anterior ramal horizontal distance from mandibular foramen was $23.91{\pm}4.79mm(range: 14.1{\sim}39.7mm)$, horizontal width of mandibular foramen was $2.79{\pm}0.95mm(range:1.5{\sim}6.1mm)$, height of lingula was $10.51{\pm}3.84mm(range:3.1{\sim}22.4mm)$, vertical distance from sigmoid notch to lingula was $19.82{\pm}5.11mm(range:9.1{\sim}35.3mm)$. From this study, the result could be used to select the location of osteotomy lines and to decide amount of periosteal elevation to avoid injury of neurovascular bundle, and to accomplish the appropriate split in Korean patients in mandibular orthognathic surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.4
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• pp.203-207
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• 2015

Osteomyelitis is classified into three groups according to its origin: osteomyelitis that originates from the blood supply, osteomyelitis related to bone disease or vascular disease, and osteomyelitis related to a local infection of dental or non-dental origin. The present case involved osteomyelitis related to a local infection of dental origin and was located in the rear area of the lingula of the mandible. We decided to use sagittal split ramus osteotomy to access the osteomyelitis area. Under general anesthesia, we successfully performed surgical sequestrectomy and curettage via sagittal split ramus osteotomy.

• Imaging Science in Dentistry
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• v.48 no.3
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• pp.185-190
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• 2018

Purpose: The aim of this study was to compare the location and the shape of the mandibular lingula in skeletal class I and III patients using panoramic radiography and cone-beam computed tomography. Materials and Methods: The sample group included 190 skeletal class I patients and 157 class III patients. The location of the lingula in relation to the deepest point of the coronoid notch was classified into 3 types using panoramic radiographs. The shapes of the lingulae were classified into nodular, triangular, truncated, or assimilated types using cone-beam computed tomographic images. The data were analyzed using the chi-square test. Results: The tips of the lingulae were at the same level as the coronoid notch in 75.3% of skeletal class I patients and above the coronoid notch in 66.6% of class III patients. The positions of the lingulae in relation to the deepest point of the coronoid notch showed statistically significant differences between class I and class III patients. The most common shape was nodular, and the least common was the assimilated shape. Although this trend was not statistically significant, the triangular shape was more frequently observed in class III patients than in class I patients. Conclusion: The locations and the shapes of the mandibular lingulae were variable. Most of the lingulae were at the same level as the coronoid notch in skeletal class I patients and above the coronoid notch in skeletal class III patients. The nodular and assimilated-shaped lingulae were the most and the least prevalent, respectively.

• Archives of Craniofacial Surgery
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• v.23 no.3
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• pp.103-110
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• 2022

Background: The primary objectives of mandibular surgery are to achieve optimal occlusion, low sensory disturbance, and adequate fixation with early movement. In-depth knowledge of the mandibular structure is required to achieve these goals. This study used computed tomography (CT) to evaluate the mandibular cortical thickness and cancellous space according to age and sex. Methods: We enrolled 230 consecutive patients, aged 20 to 50 years, who underwent CT scanning. The cortex and cancellous space centered around the inferior alveolar nerve (IAN) canal were measured at two specific locations: the lingula and second molar region. Statistical analysis of differences according to increasing age and sex was performed. Results: The t-test revealed that the cancellous space and cortical thickness differed significantly with respect to the threshold of 35 years of age. Both cortical thickness and cancellous space in the molar region were negatively correlated with age. Meanwhile, both cortical thickness and cancellous space in the lingula region showed a positive correlation with age. With respect to sex, significant differences in the cancellous space at the molar region and the cortical thickness at the lingula were observed. However, no further statistically significant differences were observed in other variables with respect to sex. The sum of each measurement on the mandibular body reflected the safe distance from the surface of the outer cortex to the IAN canal. The safe distances also showed statistically significant differences between those above and below 35 years of age. Conclusion: Knowledge of the anatomical structure of the mandible and of changes in bone structure is crucial to ensure optimal surgical outcomes and avoid damage to the IAN. CT examination is useful to identify changes in the bone structure, and these should be taken into account in the planning of surgery for older patients.