• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.5
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• pp.325-329
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• 2020

Classic anesthetic techniques for the inferior alveolar nerve, lingual nerve, and long buccal nerve blockade are achieved by estimating the intended location for anesthetic deposition based on palpation, inspection, and subsequent correlation for oral anatomical structures. The present article utilizes computed tomography (CT) data to 3D print a guide for repeatable and accurate deposition of a local anesthetic at the ideal location. This technical report aims to anatomically define the ideal location for local anesthetic deposition. This process has the potential to reduce patient discomfort, risk of nerve damage, and failed mandibular anesthesia, as well as to reduce the total anesthetic dose. Lastly, as robotic-based interventions improve, this provides the initial framework for robot-guided regional anesthesia administration in the oral cavity.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.105-109
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• 2013

Purpose: Preoperative radiographic assessment of the mandibular third molars is essential to prevent inferior alveolar nerve damage during extraction. The purpose of this study was to assess the reliability of panoramic signs of association between the roots of teeth and the canal, and to compare the panoramic signs with cone beam computed tomography (CBCT) findings. Materials and Methods: CBCT images of 132 impacted mandibular third molars were evaluated to determine the association of the root to the canal. The CBCT findings were compared with the corresponding panoramic images. Logistic regression analysis was used to define the diagnostic criteria of the panoramic images. Results: Among the panoramic signs, loss of the cortical line was the most frequent radiographic sign predicting association (sensitivity: 79.31). Contact of the tooth with the canal was observed in all cases in which the loss of cortical line of the canal or darkening of the roots was found on the panoramic radiographs. Conclusion: Darkening of the roots and loss of the cortical line on panoramic radiographs might be highly suggestive of the risk of nerve injury.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.320-326
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• 2016

The fracture of a needle during local anesthesia in dental treatment is rare; however, when it occurs, the needle should be removed without damage to surrounding structures as soon as possible. A fractured needle fragment that is buried in soft tissue would be difficult to remove, and a careful surgical procedure under general anesthesia is recommended in such cases. Children who require dental treatment are often not capable of cooperative behavior, thus unexpected movements can increase the risk of needle fracture. Clinicians can reduce the incidence of needle fracture accidents with a few precautions. In the present case report, we report a case of needle fracture due to abrupt movement during inferior alveolar nerve block anesthesia in a young child, with the purpose of drawing attention to needle fracture incidents. This report describes the possible causes and prevention methods of local anesthetic needle fracture, and the localization methods and surgical procedure for needle fragment removal.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.25.1-25.9
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• 2015

Background: During the orthognathic surgery, it is important to know the exact anatomical location of the mandibular foramen to achieve successful anesthesia of inferior alveolar nerve and to prevent damage to the nerves and vessels supplying the mandible. Methods: Cone-beam computed tomography (CBCT) was used to determine the location of the mandibular foramen in 100 patients: 30 patients with normal occlusion (13 men, 17 women), 40 patients with skeletal class II malocclusion (15 men, 25 women), 30 patients with skeletal class III malocclusion (17 men, 13 women). Results: The distance from the anterior border of the mandibular ramus to mandibular foramen did not differ significantly among the three groups, but in the group with skeletal class III malocclusion, this distance was an average of $1.43{\pm}1.95mm$ longer in the men than in the women (p < 0.05). In the skeletal class III malocclusion group, the mandibular foramen was higher than in the other two groups and was an average of $1.85{\pm}3.23mm$ higher in the men than in the women for all three groups combined (p < 0.05). The diameter of the ramus did not differ significantly among the three groups but was an average of $1.03{\pm}2.58mm$ wider in the men than in the women for all three groups combined (p < 0.05). In the skeletal class III malocclusion group, the ramus was longer than in the other groups and was an average of $7.9{\pm}3.66mm$ longer in the men than women. Conclusions: The location of the mandibular foramen was higher in the skeletal class III malocclusion group than in the other two groups, possibly because the ramus itself was longer in this group. This information should improve the success rate for inferior alveolar nerve anesthesia and decrease the complications that attend orthognathic surgery.

• Imaging Science in Dentistry
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• v.40 no.2
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• pp.75-81
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• 2010

Purpose : This study is aimed to evaluate the position of mandibular foramen of mandibula prognathism patients using 3-dimensional CT images in order to reduce the chance of an anesthetic failure of the mandibular nerve and to prevent the damage to the inferior alveolar nerve during the orthognathic surgery. Materials and Methods : The control group consist of 30 patients with class I occlusion. The experimental group consist of 44 patients with class III malocclusion. Three-dimensional computed tomography was used to evaluate the position of the mandibular foramina. Results : The distance between mandibular plane and mandibular foramen, class I was 25.385 mm, class III was 23.628 mm. About the distance between occlusal plane and mandibular foramen, class I was 1.478 mm, class III was 5.144 mm. The distance between posterior border plan of mandibular ramus and mandibular foramen had not statistically significant. About the distance between sagittal plane of mandible and mandibular foramen did not also showed statistically significant. Conclusion : The result of this study could help the clinicians to apprehend more accurate anatomical locations of the foramina on the mandible with various facial skeletal types. thereby to perform more accurate block anesthesia of the mandibular nerve and osteotomy with minimal nerve damage. In addition, this study could provide fundamental data for any related researches about the location of the mandibular foramina for other purposes.

• Imaging Science in Dentistry
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• v.49 no.3
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• pp.213-218
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• 2019

Purpose: The aim of this study was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using cone-beam computed tomography (CBCT) and to compare the CBCT findings with signs on panoramic radiographs(PRs). Materials and Methods: This retrospective study consisted of 200 mandibular third molars from 200 patients who showed a close relationship between the mandibular canal and impacted third molars on PRs and were referred for a CBCT examination of the position of the mandibular canal. The sample consisted of 124 females and 76 males, with ages ranging from 18 to 47 years (mean, $25.75{\pm}6.15$ years). PRs were evaluated for interruption of the mandibular canal wall, darkening of the roots, diversion of the mandibular canal, and narrowing of the mandibular canal. Correlations between the PR and CBCT findings were statistically analyzed. Results: In total, 146 cases(73%) showed an absence of canal cortication between the mandibular canal and impacted third molar on CBCT images. A statistically significant relationship was found between CBCT and PR findings (P<0.05). The absence of canal cortication on CBCT images was most frequently accompanied by the PR sign of diversion of the mandibular canal(96%) and least frequently by interruption of the mandibular canal wall(65%). Conclusion: CBCT examinations are highly recommended when diversion of the mandibular canal is observed on PR images to reduce the risk of mandibular nerve injury, and this sign appears to be more relevant than other PR signs.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.3
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• pp.276-280
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• 2011

BSSRO (bilateral sagittal split ramus osteotomy) is an effective surgical method for maxillofacial deformities. Rigid fixation using a plate and screws can stabilize bony segments and induce early mouth opening. Though this procedure has a low complication rate, normal function and esthetic recovery is achieved through proper and early management of the complications. Complications consisting of temporomandibular disorders, sensory disturbances due to inferior alveolar nerve damage, open bite, malunion or nonunion, and facial nerve palsy occur, but these rarely develop. Facial nerve palsy causes the muscles involved in facial expression to depress, which results in ocular dryness or retinal damage. When facial nerve palsy develops, early management involving steroid medication and physical therapy is effective. In the case of severe damage, surgical intervention should be considered. A 20-year-male patient came to the oral and maxillofacial surgery department for orthognathic surgery. The mandible was set back by BSSRO under general anesthesia. Facial nerve palsy was observed on the left side of the face: steroid and vitamins were administered early and physical therapy was performed daily. These forms of management can aid in function and allow for gradual esthetic recovery. Presumed causes were excessive soft tissue retraction or soft tissue injury by the osteotome at the horizontal osteotomy of the ramus. Careful dissection, retraction and a precise osteotomy are needed for protection of the facial nerve. If nerve damage is observed, early management can help in the recovery of facial nerve function and esthetics.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.5
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• pp.297-302
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• 2022

Objectives: This retrospective study aimed to analyze data on nerve damage in patients who complained of sensory changes after dental implant surgery, the clinical results according to proximity of the implant fixture to the inferior alveolar nerve (IAN) canal, and the factors affecting recovery of sensation. Materials and Methods: The electronic medical records of 64 patients who had experienced sensory change after implant surgery were reviewed. Patients were classified by sex, age, implant installation sites, recovery rate and the distance between the implant fixture and IAN canal on computed tomography (CT). The distance was classified into Group I (D>2 mm), Group II (2 mm≥D>0 mm), and Group III (D≤0 mm). Results: The 64 patients were included and the mean age was 57.3±7.3 years. Among the 36 patients who visited our clinic more than two times, 21 patients (58.3%) reported improvement in sensation, 13 patients (36.1%) had no change in sensation, and 2 patients (5.6%) reported worsening sensation. In Group II, symptom improvement was achieved in all patients regardless of the removal of the implant fixture. In Group III, 8 patients (40.0%) had reported symptom improvement with removal of the implant fixture, and 2 patients (33.3%) of recovered patients showed improvement without removal. Removal of the implant fixture in Group III did not result in any significant difference in recovery (P=0.337), although there was a higher possibility of improvement in sensation in removal cases. Conclusion: Clinicians first should consider removing the fixture when it directly invades the IAN canal. However, in cases of sensory change after dental implant surgery where the drill or implant fixture did not invade the IAN canal, other indirect factors such as flap elevation and damage due to anesthesia should be considered as causes of sensory change. Removal of the implant should be considered with caution in these situations.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.231-239
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• 2012

Objectives: This study sought to provide guidelines in order to decrease the incidence of nerve injury during mandibular ramus bone harvesting, and to improve understanding of the anatomical structure of the inferior alveolar canal (IAC) to include its distance from the exterior buccal cortex. Materials and Methods: In January and February 2009, 20 patients who visited the Wonkwang University Department of Oral and Maxillofacial Surgery reporting various conditions underwent cone beam computed tomography and were included in this study. Patients with missing left or right mandibular first molars or incisors, or who had jaw fracture or bone pathologies, were excluded. The reference point (R point) was defined as the point where the occlusal plane reached the anterior ramus of the mandible. The position of the IAC in relation to the R point, the buccal bone width (BW), the alveolar crest distance (ACD), the distance from the alveolar crest to the occlusal plane (COD), and the distance from the IAC to the sagittal plane (CS) were determined using proprietary image analysis software which produced cross-sectional coronal and axial images. Results: The distance medially from the R point to the IAC along the axial plane was $6.19{\pm}1.21mm$. The HD from the R point, posteriorly to IAC, in the lateral view was $13.07{\pm}2.45mm$, the VD from the R point was $14.24{\pm}2.41mm$, and the ND from the R point was $10.12{\pm}1.76mm$. The pathway of the IAC was positioned almost in a straight line along a sagittal plane within $0.56{\pm}0.70mm$. The distance from the buccal bone surface to the IAC increased anteriorly from the R point. Conclusion: Marking osteotomy lines in the retromolar area in procedures involving bone harvesting should be discouraged due to the risk of damage to IAC structures. Our measurements indicated that the area from the R point in the ramus of the mandible to 10 mm anterior can be safely harvested for bone grafting purposes.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.655-661
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• 2010

Objectives : This study is aimed to prevent the damage to the inferior alveolar nerve during the orthognathic surgery. Methods : The control group consist of 50 patients with class I occlusion. The experimental group consist of 50 patients with class III malocclusion. The cepalometric radiography was used to evaluate the position of the mental foramina. Results : In the first, mental foramen position of class III was more inferior 0.85 mm in the distance between base of mandible and mental foramen. But the distance between occlusal plan and mental foramen had not statistically significant. Secondly, mental foramen location of Mandibular Prognathism was more anterior 0.91 mm in the distance between coronal plane of mandible included pogonion point and mental foramen. Also, the distance of occlusal-coronal plane of mandible included central incisor and mental foramen had statistically significant. The mental foramen location of class III was more anterior 4.81 mm than class I patients. Conclusions : The result of this study could help the clinicians to apprehend fundamental data with various facial skeletal types for any related researches about the location of the mental foramina for other purposes.