• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.5
• /
• pp.329-334
• /
• 2009

Objective: To evaluate the ratio between bone-contact length and inter-segmental length of the rigid fixation screw used in bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. Material and Methods: Records of 40 patients with Class III malocclusion were selected. 20 of them had BSSRO, while the other 20 had BSSRO with maxillary LeFort I osteotomy. All of the patients had three noncompressive bicortical screws inserted at the gonial angle through transcutaneous approach. Two screws were inserted antero-posteriorly above inferior alveolar nerve and one screw was inserted below. The lengths of bone-contact and that of inter-segmental part were measured using cone-beam computed tomography. Ratio between these two measured lengths was calculated. Results: Both bone-contact and inter-segmental lengths were longer in BSSRO group than in BSSRO with maxillary LeFort I osteotomy group. Ratio of bone-contact to inter-segmental length was lower in BSSRO group than in BSSRO with Lefort I group. Both bone-contact and inter-segmental lengths were longer at the antero-superior position than at the inferior position. However, their ratio showed little difference. Conclusion: This study suggest that stability of screws in BSSRO group was greater than in BSSRO with Lefort I group. Stability of screws at the antero-superior position was greater than at the inferior position. Ratio of bone-contact to inter-segmental lengths was 0.2 in average.

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

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.13 no.1
• /
• pp.30-36
• /
• 1991

Various nerves from many areas of body can be used as a donor of autogenous nerve graft in the microneurosurgical repair of the oral and maxillofacial region. In the grafting procedure of nerve repair, the best results will be achieved with a maximum approximation of fascicular surface at both the porximal and the distal stumps. Therefore, appropriate selection of donor nerve will bring out the best results. The sural nerve has been used as one of the most popular donor nerve in the microneurosurgical repair of the oral and maxillofacial region. The authors examined the fascicular characteristics of the human sural nerve microscopically and compare this results with our previous report of the greater auricular nerve and that of the inferior alveolar nerve.

• Imaging Science in Dentistry
• /
• v.52 no.2
• /
• pp.141-153
• /
• 2022

Purpose: This study aimed to identify the prevalence and extension of the anterior loop (AL) of the mental nerve in different populations and according to different cone-beam computed tomography (CBCT) imaging settings. Materials and Methods: Medline/PubMed, Embase, Scopus, Web of Science, and ProQuest were searched. The main inclusion criterion was ALs evaluated in CBCT images. The quality of studies was assessed with the Joanna Briggs Institute risk of bias checklist. Subgroup analyses were conducted for sex, side, continent, voxel size, field of view, and type of CBCT-reconstruction images with a random-effects model. Results: Sixty-three studies with 13,743 participants (27,075 hemimandibles) were included. An AL was found in 40.6% (95% CI: 32.8%-48.9%, P<0.05) of participants and 36.0% (95% CI: 27.5%-45.5%, P<0.05) of hemimandibles, in 34.9% (95% CI: 25.1%-46.2%, P<0.05) of males and 34.5% (95% CI: 23.5%-47.4%, P<0.05) of females. The average length of ALs was 2.39 mm (95% CI: 2.07-2.70 mm, P<0.05). Their extension was 2.13 mm (95% CI: 1.54-2.73 mm, P<0.05) in males and 1.85 mm (95% CI: 1.35-2.36 mm, P<0.05) in females. Significant differences were observed regarding the prevalence and length of ALs among continents and for its measured length on different CBCT-reconstruction images, but not between other subgroups. Conclusion: AL was a relatively common finding. The voxel size and fields of view of CBCT devices were adequate for assessing AL; however, a 2-mm safety margin from anatomical structures(such as the AL) could be recommended to be considered when using CBCT imaging.

• Restorative Dentistry and Endodontics
• /
• v.15 no.1
• /
• pp.1-15
• /
• 1990

The aim of this study was to investigate the effect of dental therapeutic agent on conduction velocity and threshold current of intradental A- and C-fibers in the cat. Inferior alveolar nerve of cat anesthetized with sodium pentobarbital was exposed and dissected until response of functional single pulp nerve until could be evoked by monopolar electrical stimulation of the crown of the lower left canine teeth. 10ms rectangular pulse was used to determine the threshold current and 1ms rectangular pulse was used to determine conduction velocity. After application of calcium chloride (1, 2, 6M), calcium hydroxide mixed with saline, potassium chloride (0.2, 0.8, 1.6M), eugenol, zinc oxide eugenol to the cavity on the labial surface, conduction velocity and threshold current of single pulp nerve unit were compared with the control. In 10 cats, 24 $A{\delta}$- and 11 C- pulp nerve units were recorded. The mean conduction velocities of $A{\delta}$- and C-fibers were 7.5m/sec (SD=5.8) and 1.2m/sec (SD=0.4), respectively. The mean threshold current was $12.3{\mu}A$ (SD=5.3) for $A{\delta}$-fibers and $24.9{\mu}A$ (SD=8.1) for C-fibers. 1, 2, 6M calcium chloride caused decrease of conduction velocity and remarkable increase of threshold current in $A{\delta}$- and C-fibers. The effect of calcium hydroxide mixed with saline was similar but smaller than calcium chloride solution. 0.2M potassium chloride had insignificant effect. In 0.8M potassium chloride, the threshold current was increased although conduction velocity was not affected. In 1.6M potassium chloride, the threshold current was increased and the conduction velocity was slowed down. Spontaneous activity was recorded frequently for first 5 min but gradually reduced both in $A{\delta}$- and C-fibers. Eugenol had irreversible effect on pulp nerve in that initially there were not certain changes in the conduction velocity and threshold current of $A{\delta}$- and C-fibers, but the responses to electrical stimulation were abruptly disappeared after sustained application and were not recovered. Contrary to eugenol, zinc oxide eugenol did not caused significant increase of the threhold current and caused time dependent decrease of the conduction velocity, and did not show any irreversible change.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.35 no.1
• /
• pp.37-45
• /
• 2019

In the case of edentulous patients, the total amount of occlusal force is dispersed by the keratinized gingiva during mastication, in result, causing lower masticatory and chewing efficiency. In particular, the mandibular area has more side effects such as pain than the maxilla has. It gets worse when the patient has more absorption of alveolar bone, but the implant treatment is often interrupted due to the existence of the inferior alveolar nerve. In this case, a patient treated with the all-on-4 method by placing the implant in the anterior part of mandible and with the conventional complete denture for the maxilla has maintained without complications and was satisfied with the restoration both functionally and esthetically.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.49 no.2
• /
• pp.100-104
• /
• 2023

Autogenous bone grafts from the mandibular ramus are a known source of inadequate bone volume scenarios of the residual alveolar ridge. However, the conventional block-type harvesting technique cannot prevent bone marrow invasion, which can cause postoperative complications such as pain, swelling, and inferior alveolar nerve injury. This study aims to suggest a complication-free harvesting technique and present the results of bone grafting and donor sites. One patient received two dental implants with a complication-free harvesting technique that involves creation of ditching holes with a 1 mm round bur. Sagittal, coronal, and axial osteotomies produced grid-type cortical squares using a micro-saw and a round bur to confirm the cortical thickness. The grid-type cortical bone was harvested from the occlusal aspect, and the harvesting was extended through an additional osteotomy on the exposed and remaining cortical bone to prevent bone marrow invasion. The patient did not suffer postoperative severe pain, swelling, or numbness. After 15 months, the harvested site exhibited new cortical bone lining, and the grafted area had healed to a cortico-cancellous complex with functional loading of the implants. Our technique, grid-type cortical bone harvesting without bone marrow invasion, allowed application of autogenous bone without bone marrow invasion to achieve acceptable bone healing of the dental implants and to regenerate the harvested cortical bone.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.17 no.1
• /
• pp.46-54
• /
• 1995

Postoperative infection following orthognatic surgery is rare. When postoperative infections occur, the initial treatment consists of incision and drainage of the affected area, culturing to identify bacterial stains and verify antibiotic sensitivity, and the institution of the appropriate antibiotic regimen. Some plates and screws may eventually require removal, the initial therapy should be attempted to retain the plates and screws until adequete healing has taken place. In orthoganthic surgery, intra-operative complications as a lesion of inferior alveolar nerve, fracture of osteomised segments, incomplete sectioning, malposition of segments, haemorrhage may occur. The surgeon should be familiar with possible complications to be caused and how to manage them. Prevention of postoperative infection following the orthognathic surgery consists of minimal periosteal reflection, aseptic management of operation field, proper surgical technique, rigid fixation, prophylactic antibiotics.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.13 no.1
• /
• pp.117-126
• /
• 1983

The mandibular canal must be considered carefully during surgical treatment, especially surgical extraction of the impacted tooth and intraosseous implant because it contains the important inferior alveolar nerve and vessels. The author investigated the curvatUre of the mandibular canal, the positional frequency of mandibular foramen to the occlusal plane and gonial angle and the positional frequency of the mental foramen to the tooth site using orthopantomograms. The materials consisted of 295 orthopantomograms divided into seven groups ranging from the first decade to 6th. decade. The results were as follows: 1. The position of mandibular foramen was most frequently below occlusal plane in Group Ⅰ (78.6%) and Group Ⅱ (71.2%), above occlusal plane in Group Ⅲ (63.0%), Group IV (71.1%), Group V (57.6%), Group (76.7%) and Group VII (70.0%). 2. The curvature of mandibular canal was 142.8° in Group Ⅰ, 142.09° in Group Ⅱ, 139.34° in Group Ⅲ, 141.48° in Group Ⅳ, 138.45° in Group Ⅴ, 140.77° in Group Ⅵ and 143.89° in Group Ⅶ. 3. The gonial angie was 125.82° in Group Ⅰ, 123.18° in Group Ⅱ, 124.06° in Group Ⅲ, 120.45° in Group Ⅳ, 121.12° in Group Ⅴ, 121.63° in Group Ⅵ and 121.24° in Group Ⅶ. 4. The position of the menta] foramen was most frequently below the apex of mandibular first premolar in Group Ⅰ (57.2%), between the apex of mandibular first and second premolar in Group Ⅱ (59.6%) and Group Ⅲ (48.9%), and below the apex of mandibular second premolar in Group Ⅳ (39.2%), Group Ⅴ (48.5%) Group Ⅵ(46.6%) and Group Ⅶ(56.4%)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.4
• /
• pp.286-290
• /
• 2010

Various treatment methods for huge cystic lesion of the jaw exist, such as, resection of the involved bone, enucleation and decompression. Among these methods, enucleation after decompression is a conservative technique that decreases the size of the cystic cavity and reduces the risk of intrabony defects, which could be induced by primary enucleation. In addition, it can save the adjacent anatomic structures. In these cases, the decompression combined with partial enucleation, which was performed before complete cyst enucleation was performed on huge cystic lesions of the mandible. During the process, a decrease in the size of the lesion and the growth of normal oral tissues was observed. The size of the lesion decreased until the time of complete enucleation, and surgery could be performed under local anesthesia. No damage to inferior alveolar nerve was observed. We report these cases with a review of the relevant literature.