OBJECTIVES: This study aims to evaluate the changes in the mandibular canal following the treatment of large odontogenic keratocysts through decompression and curettage, providing a theoretical basis for sequential treatment. METHODS: Twenty patients were selected for each decompression and curettage treatment of large odontogenic keratocysts in the mandible. Postoperative follow-up with was conducted every three months, during which cone beam computed tomography (CBCT) scans were performed. Then, the data were imported into MIMICS software to observe 3D changes in the position and structure of the mandibular nerve canal, followed by a comparative analysis. RESULTS: The total displacement of the mandibular canal was (1.89±0.21) mm on the decompression side and (0.80±0.19) mm on the curettage side. Vertically, the displacement range of the mandibular canal on the decompression side (M=1.03, SD=0.17) was larger than on the curettage side (M=0.52, SD=0.010) within nine months post-operation. In the buccal-lingual direction, the ratio of the thickness of the buccal plate to the lingual plate gradually increased with time. The amount of bone reconstruction at the part of the mandibular nerve canal closest to the cyst was (1.75±0.15) mm on the decompression side and (1.45±0.09) mm on the curettage side after nine months. CONCLUSIONS The mandibular nerve canal showed varying degrees of recovery and "relocation" after two surgical procedures. Osteogenesis around the mandibular nerve canal was more remarkable after decompression than after curettage. Therefore, for large odontogenic keratocyst, decompression is recommended as the initial treatment, followed by secondary curettage nine months later.
Humans ; Odontogenic Cysts/diagnostic imaging* ; Retrospective Studies ; Cone-Beam Computed Tomography ; Decompression, Surgical/methods* ; Mandibular Nerve/surgery* ; Mandible/innervation* ; Curettage ; Male ; Female ; Adult ; Middle Aged

It is difficult to distinguish the inferior alveolar nerve (IAN) from other tissues inside the IAN canal due to their similar CT values in the X image which are smaller than that of the bones. The direct reconstruction, therefore, is difficult to achieve the effects. The traditional clinical treatments mainly rely on doctors' manually drawing the X images so that some subjective results could not be avoided. This paper proposes the partition reconstruction of IAN canal based on shape features. According to the anatomical features of the IAN canal, we divided the image into three parts and treated the three parts differently. For the first, the directly part of the mandibular, we used Shape-driven Level-set Algorithm Restrained by Local Information (BSLARLI) segment IAN canal. For the second part, the mandibular body, we used Space B-spline curve fitting IAN canal's center, then along the center curve established the cross section. And for the third part, the mental foramen, we used an adaptive threshold Canny algorithm to extract IAN canal's edge to find center curve, and then along it established the cross section similarly. Finally we used the Visualization Toolkit (VTK) to reconstruct the CT data as mentioned above. The VTK reconstruction result by setting a different opacity and color values of tissues CT data can perspectively display the INA canal clearly. The reconstruction result by using this method is smoother than that using the segmentation results and the anatomical structure of mental foramen position is similar to the real tissues, so it provides an effective method for locating the spatial position of the IAN canal for implant surgeries.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; Mandible ; innervation ; Mandibular Nerve ; anatomy & histology

OBJECTIVETo study the anatomy of mandibular bone flap pedicled with temporal muscle for midfacial bone defects.

METHODSThe shape and blood supply of the temporal muscle and mandibular ramus, as well as their relationship, were observed and measured in 30 sides of adult head specimens.

RESULTSThe temporal muscle has a fan-shaped main portion, then is scattered into three bundles as anterolateral, anteromedial, posterior bundles, which end respectively at anterior border of ramus, the temporal ridge and posterior portion of coronoid process. Then the muscle goes downward until it reaches the distal side of the third medial surface molar and attaches the 3/4 of medial surface of anterior portion of ramus. The blood supply of temporal muscle includes the medial temporal artery with external diameter of (0.76 +/- 0.20) mm, the anterior deep temporal arteries with external diameter of (0.79 +/- 0.21) mm, posterior deep temporal arteries with external diameter of (0.98 +/- 0.64) mm, the accessory deep temporal artery formed by many little branches. The anterior part of ramus is supplied by the periosteal arteries and the bony perforator of the deep temporal arteries. Rectangular ramus of mandible was divided into anterior portion and posterior portion by the line linking the lowest point of mandibular notch, mandibular foramen and mandibular canal. Anterior portion can supply a bone flap with a size of (46.67 +/- 6.85) mm x (17.98 +/- 2.64) mm x (11.49 +/- 0.99) mm.

CONCLUSIONSThe mandibular bone flap pedicled with temporal muscle has a reliable blood supply and abundant bone volume. It is feasible to design a mandibular bone flap pedicled with temporal muscle for midfacial bone defect.

Adult ; Bone Transplantation ; Female ; Humans ; Male ; Mandible ; anatomy & histology ; surgery ; Surgical Flaps ; Temporal Muscle ; anatomy & histology ; blood supply ; innervation

OBJECTIVETo decrease the incidence of inferior alveolar neurovascular bundle injury through location of mandibular canal by 3-dimensional (3-D) CT.

METHODS30 female cases with prominent mandibular angle underwent 3-D CT before operation. The 3-D images were used to measure the distances between upper points of lower teeth to the inferior border of the canal. Then the osteotomy was designed according to the canal position to avoid the inferior alveolar neurovascular bundle injury. The canal protection was observed intraoperatively and postoperatively.

RESULTSThe mandibular canal was protected very well in all 30 cases without any injury to the inferior alveolar neurovascular bundle.

CONCLUSIONSThe 3-D CT can accurately locate the mandibular canal to guide the design of the mandibular angle osteotomy for patients with prominent mandibular angle.

Adult ; Female ; Humans ; Imaging, Three-Dimensional ; Mandible ; diagnostic imaging ; innervation ; surgery ; Mandibular Nerve ; diagnostic imaging ; Neural Tube ; diagnostic imaging ; Tomography, X-Ray Computed

OBJECTIVETo study the course and distribution of buccal and marginal mandibular branches of facial nerve, and its relevance to the treatment of facial paralysis and the protection of facial nerve during surgery.

METHODS12 cadaver heads were dissected (24 specimens). The course of the buccal and marginal mandibular branch and the interconnections between them were observed. The relationship of buccal branch to parotid duct, marginal mandibular branch to the inferior border of mandible were studied. With modified Sihler's staining technique, the distribution of facial nerve branches in innervated mimetic muscles was displayed. These anatomic relationships mentioned above were further confirmed during the operation of 40 patients with facial paralysis.

RESULTSParotid duct had a constant surface landmark. Buccal branch mainly consisted of 2-3 ramifications in 87.5% of the specimens, while marginal mandibular branch was double or single in 95.9% of the specimens. The buccal branch coursed within the distance between 10.7 mm above and 9.3 mm below the parotid duct, and innervated mimetic muscles of midface. The marginal mandibular branch coursed within the distance between 13.4 mm above and 4.8 mm below the lower border of mandible, crossed superiorly the facial artery and innervated mimetic muscles of lower lip.

CONCLUSIONSThere is a close relationship of buccal branch to parotid duct and marginal mandibular branch to facial artery and lower border of mandible. With modified Sihler's staining technique, the original 3-dimensional picture of the intramuscular nerve distribution in human mimetic muscles.

Adult ; Facial Nerve ; anatomy & histology ; Facial Paralysis ; surgery ; Female ; Humans ; In Vitro Techniques ; Male ; Mandible ; anatomy & histology ; innervation

OBJECTIVETo assess sensory function of inferior alveolar nerve in monkeys with mandibular distraction osteogenesis by use of trigeminal somatosensory evoked potential (TSEP).

METHODSeven young monkeys, 4 approximately 6 kg, were undergone a 13.5 mm bilateral or right-side mandibular lengthening with mandibular angle osteotomy and intraoral bone-born appliance. The inferior alveolar nerve function was assessed with TSEP before surgery, at the completion of distraction, and after four weeks of fixation.

RESULTSNo significant differences in latencies and amplitudes of TSEP between the left and right inferior alveolar nerves before surgery. At the completion of distraction, latencies of TSEP showed significant elongation (P < 0.01, P < 0.001) and amplitudes also significantly decreased (P < 0.001). After four weeks of fixation, various degrees of TSEP recovery were identified. The latencies and the amplitude were slightly improved.

CONCLUSIONSMandibular distraction osteogenesis affects sensory function of inferior alveolar nerves in studied monkeys evaluated with SEP, but recovery is observed four weeks after surgery.

Alveolar Process ; innervation ; Animals ; Evoked Potentials, Somatosensory ; Female ; Haplorhini ; Male ; Mandible ; surgery ; Osteogenesis, Distraction ; Trigeminal Nerve ; physiology

OBJECTIVEThe aim of this study was to rebuild the anatomic structures of the mandibular bone and the canal, and to testify the reliability of the rebuilt model.

METHODS15 mandibular bones with teeth are chosen, and a three-dimensional model was built with the method of CT. The slices vertical to the compensating curve were made in every dental position. Then the authors collected the data of alveoli and mandibular canal in every slice. The same work was done to the bone specimen, and then comparative analysis was done.

RESULTSThe wideness of the alveoli and 10 mm bellow increased from mesial to distal position. It was the same of the alveoli from the top to the bottom. The mandibular canal lied in the inner and inferior side of the mandibular body. There was no significant difference in data collected with these two methods.

CONCLUSIONDifferent types of dental implants should be chosen according to the anatomic characteristic of the mandibular bone in every dental position before the operation to avoid complications. And a reliable, accurate and direct method of planning an implant operation is to rebuild a three-dimensional model.

Adult ; Computer Graphics ; Humans ; Mandible ; anatomy & histology ; diagnostic imaging ; innervation ; Mandibular Nerve ; anatomy & histology ; Models, Anatomic ; Tomography, Spiral Computed ; methods