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Concept: Mandibular canal

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Background: Topography and fascicular arrangement of the inferior alveolar nerve (IAN) can provide critical information for the estimation of damage to IAN based on patient symptoms, or conversely to evaluate the symptoms resulting from injury to the IAN. Purpose: The fascicular composition and organization of the IAN were determined to confirm the microarchitecture of the IAN bundles into each of the mandibular teeth, including the composition of the mental nerve. Materials and Methods: The IAN within the mandibular canal (MC) was examined in 30 hemifaces of embalmed Korean cadavers. Results: The most common patterns of nerve fascicle innervation to the mandibular teeth could be grossly classified into three: (1) the superior buccal portion of the IAN innervating the molars, (2) the superior portion innervating the premolars, and (3) the superior lingual or the superior lingual and inferior lingual portions in the posterior MC and the lingual portions in the anterior MC, innervating the incisors and canine. The buccal two-thirds portion of the IAN was composed of the mental nerve. Conclusion: The IAN had distinctive fascicular organizations, which make it possible to forecast the degree, location, and extent of nerve damage according to presenting symptoms.

Concepts: Cranial nerves, Teeth, Mandibular nerve, Incisor, Canine tooth, Inferior alveolar nerve, Mandibular canal, Mental nerve

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The purposes of this study were (1) to investigate the bucco-lingual course of the mandibular canal in the bony structure and (2) to figure out the relationship between the position of mental foramen on panoramic radiographs and the horizontal course of the mandibular canal.

Concepts: Foramina of the skull, Inferior alveolar nerve, Mandibular canal, Mental nerve

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Abstract Objective. To examine whether the rapid increase in the availability of cone-beam computed tomography (CBCT) has changed the number of inferior alveolar nerve (IAN) injuries related to the removal of mandibular third molars in Finland. The hypothesis was that the number of nerve injuries should diminish due to better imaging methods. Materials and methods. The number of CBCT devices, the annual number of CBCT examinations and the number of permanent IAN injuries occurring between 1997 and 2007 were analyzed. The data was collected from three national registers: the Radiation and Nuclear Safety Authority, the Social Insurance Institution and the Patient Insurance Centre. A detailed analysis was made from the cases of permanent IAN injuries. Results. The first CBCT device was registered in 2002 and the cumulative number of these devices in 2009 was 22. There was an increase from 555 to 3160 in the number of annual CBCT examinations during the period 2004-2009. The total number of permanent IAN injuries during the years 1997-2007 was 129 and remained stable throughout the period (regression analysis, p = 0.974, r (2) = 0.01). Conclusions. Contrary to this hypothesis, the availability of CBCT devices has had no significant influence on the number of IAN injuries related to mandibular third molar removals in Finland. More education should be given to optimize the use of CBCT to cover difficult cases that may give rise to complications.

Concepts: Regression analysis, Horse, Teeth, Molar, Examination, Nuclear safety, Mandibular canal, Mandibular third molar

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Profound pulpal anesthesia in posterior mandibular teeth with irreversible pulpitis usually requires administering an inferior alveolar nerve block (IANB) plus other supplemental injections. The purpose of this prospective, randomized, double-blind study was to compare the anesthetic success rate of buccal infiltration injections of articaine and lidocaine when supplemented with an IANB.

Concepts: Cranial nerves, Mandibular nerve, Local anesthetic, Inferior alveolar nerve, Mandibular canal

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The study evaluates the incidence of inferior alveolar nerve injuries in mandibular fractures, the duration of their recovery, and the factors associated with them. Fifty-two patients with mandibular fractures involving the ramus, angle, and body regions were included in this study; the inferior alveolar nerve was examined for neurological deficit posttraumatically using sharp/blunt differentiation method, and during the follow-up period the progression of neural recovery was assessed. The incidence of neural injury of the inferior alveolar nerve was 42.3%, comminuted and displaced linear fractures were associated with higher incidence of inferior alveolar nerve injury and prolonged recovery time, and recovery of inferior alveolar nerve function occurred in 91%.Fractures of the mandible involving the ramus, angle, and body regions, and comminuted and displaced linear fractures are factors that increase the incidence of inferior alveolar nerve injuries. Missile injuries can be considered as another risk factor.

Concepts: Bone fracture, Function, Injury, Physical trauma, Inferior alveolar nerve, Mandibular canal

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Our aim was to explore the relation between the site of the mandibular canal and neurosensory impairment after extraction of impacted mandibular third molars. We organised a retrospective study of 537 extractions in 318 patients in which the affected tooth was intersected by the mandibular canal. This was verified by cone-beam computed tomography (CBCT), and we analysed the relation between the site of the canal and the likelihood of injury to the inferior alveolar nerve (IAN) after extraction of the third molar. The relation between the position of the root of the tooth and the mandibular canal was categorised into 4 groups: I=root above the canal; II=on the buccal side; III=on the lingual side; and IV=between the roots. The overall rate of neurosensory impairment after extraction was 6% (33/537). It occurred in 9/272 patients (3%) in group 1, 16/86 (19%) in group II, and in 8/172 (5%) in group III. There was no neurosensory impairment in group IV where the canal was between the roots. There were significant differences between group II and groups I and III (p<0.01), but not between groups I and III (p=0.32). The risk of damage to the inferior alveolar nerve is increased if third molars intersect with the mandibular canal, particularly on its buccal side.

Concepts: Teeth, Molar, Mandibular nerve, Lingual nerve, Inferior alveolar nerve, Inferior alveolar artery, Mandibular canal, Mandibular third molar

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PURPOSE:: The objective of the present study was to realize an indirect morphometric evaluation of bone thickness lateral to the mandibular canal. MATERIAL AND METHODS:: In 30 partially or totally edentulous dry jaws, the first and second molar areas were analyzed using computed tomography. RESULTS:: The findings indicated that 28.33% of the sites could be considered for the installation of a standard 3.75-mm-diameter implant laterally between the mandibular canal and its bony counterpart. CONCLUSION:: Implant installation in the posterior mandible region, lateral to the mandibular canal, is an alternative to more complex techniques, such as vertical ridge augmentation.

Concepts: Present, Mandibular canal

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The aim of this study was the clinical and radiological evaluation in severe mandibular atrophy (class V-VI Cadwood-Howell) of bone grafts with homologous fresh frozen bone (FFB) in patients with dysesthesia of the inferior alveolar nerve with or without transposition of the NAI in order to perform a proper implant-prosthetic rehabilitation.

Concepts: Mandible, Cladistics, Mandibular canal

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Effective pain control during local anesthetic injection is the cornerstone of behavior guidance in pediatric dentistry. The aim of this study was to evaluate the practical efficacy of a 2-stage injection technique in reducing injection pain in children. This was a split-mouth, randomized controlled crossover trial. One hundred cooperative children aged 7 to 13 years in need of bilateral local anesthetic injections (inferior alveolar nerve block, posterior superior alveolar nerve block, or maxillary and mandibular buccal infiltrations) for restorative, endodontic, and extraction treatments were recruited for the study. Children were randomly allocated to receive either the 2-stage injection technique or conventional technique at the first appointment. The other technique was used at the successive visit after 1 week. Subjective and objective evaluation of pain was done using the Wong-Baker FACES Pain Rating Scale (FPS) and Sound Eye Motor (SEM) scale, respectively. The comparison of pain scores was done by Wilcoxon sign-rank test. Both FPS and SEM scores were significantly lower when the 2-stage injection technique of local anesthetic nerve block/infiltration was used compared with the conventional technique. The 2-stage injection technique is a simple and effective means of reducing injection pain in children.

Concepts: Anesthesia, Local anesthesia, Mandibular nerve, Intrathecal, Local anesthetic, Maxillary artery, Inferior alveolar nerve, Mandibular canal

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To prospectively evaluate the longitudinal subjective and objective outcomes of the microsurgical treatment of lingual nerve (LN) and inferior alveolar nerve (IAN) injury after third molar surgery.

Concepts: Surgery, Objective pronoun, Case series, Lingual nerve, Inferior alveolar nerve, Mandibular canal, Wisdom teeth