[Topographic features of lingual nerve and its relationship with other anatomical structures in maxillolingual groove].

By surgical interventions in maxillolingual groove area one should consider anatomical variations and topography of vessels, glands ducts and lingual nerve to prevent their injury. At the Department of Operative Surgery and Topographic Anatomy of the First Moscow State Medical University named after I.M. Sechenov we carried out anatomical study on cadavers (men and women, n=30).The study revealed topographical features of the lingual nerve and its relationship to other anatomical structures in the maxillolingual groove. It was found out that at the level of the second molar (96%) lingual nerve "crosses" duct of submandibular salivary gland, at the level of the third molar lingual nerve is located under the duct and lateral to it, closer to the inner surface of the body of the mandible. At the level of the first molar lingual nerve is located above and medial to Wharton duct and passes along sublingual-lingual muscles (m.hyoglossus).

Coronectomy; Good or Bad?

The removal of mandibular third molars can be complicated by injury to the inferior alveolar nerve (IAN). Coronectomy retains the tooth root; this method has been found to be preferable to extraction in the context of mandibular third molars. A failed coronectomy may cause mobilization of these roots, thereby requiring a subsequent extraction. Having undergone a previous coronectomy, extraction is then safer as the roots usually migrate away from the IAN. Computed tomography is more accurate than radiography when imaging mandibular third molars pre-operatively owing to its three-dimensional nature. Longer studies need to be conducted to evaluate the long term benefits of coronectomy. CPD/CLINICAL RELEVANCE: The removal of mandibular third molars can be complicated by the presence of the close lying inferior alveolar nerve. Coronectomy can be useful in this setting and therefore it is important to be aware of the pros and cons of this technique.

[Indications, feasibility and clinical experience with Vazirani-Akinozi mandibular block in limiting mouth opening and difficult anatomical conditions].

Vazirani-Akinozi technique was used in 82 patient undergoing oral surgery procedures. According to study results Vazirani-Akinozi technique was feasible in 89% of cases and particularly effective in surgical treatment of third lower molars eruption diseases complicated by inflammatory contracture. The method increases mouth opening 1.6-2.3 cm due to the soft-tissue anesthesia and partial anesthesia of masseter nerve. In case of inflammatory contracture of the jaws when inflammatory infiltration is spreading on the masseter muscle the authors recommend to use a combination of Vazirani-Akinozi and Berchet-Dubov techniques.

Evaluation of the relationship between mandibular third molar and mandibular canal by different algorithms of cone-beam computed tomography.

OBJECTIVES: Exact location of the inferior alveolar nerve (IAN) bundle is very important. The aim of this study is to evaluate the relationship between the mandibular third molar and the mandibular canal by cone-beam computed tomography. STUDY DESIGN: This was a cross-sectional study with convenience sampling. 94 mandibular CBCTs performed with CSANEX 3D machine (Soredex, Finland) and 3D system chosen. Vertical and horizontal relationship between the mandibular canal and the third molar depicted by 3D, panoramic reformat view of CBCT and cross-sectional view. Cross-sectional view was our gold standard and other view evaluated by it. RESULTS: There were significant differences between the vertical and horizontal relation of nerve and tooth in all views (p < 0.001). CONCLUSION: The results showed differences in the position of the inferior alveolar nerve with different views of CBCT, so CBCT images are not quite reliable and have possibility of error.

Endoscopically assisted removal of a lingually displaced third molar adjacent to the inferior alveolar nerve.

BACKGROUND: Osteotomy of impacted lower third molars still represents a major trauma because of periosteal flap preparation and buccal bone loss. We present a new occlusal flapless approach for the removal of lingually impacted lower third molars adjacent to the inferior alveolar nerve without lateral or lingual osteotomy. METHOD: After occlusal exposure under local anesthesia, visualization of the third molar region is obtained from a posterior perspective using support endoscopy. Under magnifying endoscopic visualization, the crown is removed using an inward fragmentation technique. After exposure of the furcation area, the roots are separated and removed via the occlusal cavity. CONCLUSIONS: Endoscopically assisted removal of mandibular third molars allows the maintenance of the adjacent bone structures and the integrity of the mandibular canal. It is valuable in complex anatomic sites in particular.

Use of cone-beam computed tomography in the diagnosis of sensory nerve paresthesia secondary to orthodontic tooth movement: a clinical report.

In this article, we report an incident of transient neuropathy secondary to tooth movement involving the inferior alveolar nerve. This clinical report reflects the need to thoroughly examine potentially high-risk patients for neuropathy using advanced diagnostic tools such as cone-beam computed tomography when diagnosing and planning treatment.

Lingual and inferior alveolar nerve injuries after third molar removal.

Trigeminal nerve injury is a rare, but serious complication of a common procedure, which results in a clinically relevant problem that deserves attention. The emergence of microsurgical repair of trigeminal injury has provided clinicians with treatment options for patients who experience persistent neurosensory deficits. The area of microsurgical repair of trigeminal nerves is now in its adolescence. While great strides have been made in the field since its conception, it is certain that a new generation of oral and maxillofacial surgeons wil bring further progress to the field. In the future, better quantitative sensory testing methods, more accurate imaging modalities, and advances in surgical technique will certainly improve the management of patients with impacted third molars. As clinicians, every day we are confronted with the management of impacted third molars. It is important to evaluate each patient individually with an appropriate clinical and radiographic exam. Every patient should be informed of the relative risks and benefits of third molar removal and a joint decision should be reached between the clinician and patient regarding ideal treatment. However, even with ideal management, complications will occur. If a patient does present with signs of a nerve injury the clinician should carefully document the neurosensory deficit and monitor the patient over time. If the patient exhibits a significant sensory deficit for more than one month a referral for evaluation to a tertiary care center capable of surgical repair of the injury is recommended. The occurrence of a "trigger" or Tinel's like sign is improtant as an indication for surgery but may not occur for a month after injury.

[Retromolar mandibular anesthesia. Radiological and topographical study of an additional method of lower teeth anesthesia].

The aim of the study was to estimate the clinical efficacy of mandibular third molars anesthesia with various combinations of local anesthesia methods. Anatomical, radiological and morphological methods were used in the study. The topographic features of retromolar triangle were thoroughly examined. The neurovascular bundle revealed its relationship with retromolar area structures. According to the results of the clinical study the most effective combinations of mandibular third molars analgesia were selected.

[Anatomical and radiological studies on additional mandible teeth anesthesia considering innervation variability].

The paper presents studies on nutritional foramina of the mandible. Some nutritional foramina located in the frontal mandibular region on the lingual surface and containing significant blood vessels and nerves are found to be more typical for teeth-bearing mandible. In retromolar area in case of third molars presence intraosseous canals were revealed leading to inferior alveolar nerve canal. One should consider intraligamental and lingual anesthesia by lower incisors extraction. Intraosseous anesthesia and retromolar area infiltration significantly increase anesthesia efficiency by third molar extraction.

Clinical significance of computed tomographic assessment and anatomic features of the inferior alveolar canal as risk factors for injury of the inferior alveolar nerve at third molar surgery.

PURPOSE: To assess the clinical features of the inferior alveolar canal (IAC) using computed tomography (CT) and to analyze the significance of CT examination at third molar surgery. MATERIALS AND METHODS: A retrospective cohort study was performed involving 99 patients (145 teeth). The relationship between cortication status, buccolingual position, and shape of the IAC on the CT image and inferior alveolar nerve (IAN) injury after third molar surgery were statistically analyzed. RESULTS: The shape of the IAC was categorized into 3 groups: round/oval, teardrop, and dumbbell. IAN injury was observed in 7 of 145 cases (4.8%). All 7 cases exhibited absence of cortication; 3 were dumbbell shape and 4 were round/oval. According to logistic regression analysis of cases with absence of cortication, IAC shape was closely related to IAN injury. CONCLUSIONS: These results suggest that assessment of the IAC shape and cortication status at third molar surgery may be clinically useful.

Does computed tomography prevent inferior alveolar nerve injuries caused by lower third molar removal?

PURPOSE: To verify the utility of computed tomography (CT) in preventing inferior alveolar nerve (IAN) injury owing to lower third molar extraction in close relation to the IAN on orthopantomogram. MATERIALS AND METHODS: A retrospective cohort study design of 150 lower third molar extractions was performed. Patients were divided in 2 groups: the CT group (n = 95) underwent panoramic radiography and mandibular CT and the control group (n = 55) underwent only panoramic radiography. RESULTS: Six extractions (4%) in the control group and 15 (10%) in the CT group resulted in IAN impairment (P > .05). Logistic regression models did not show that undergoing CT decreased the risk of IAN injury from lower third molar extraction. CONCLUSIONS: Patient age and positive radiographic signs (darkening of the root and narrowing of the inferior alveolar canal) were associated with more requests for CT scanning. CT does not seem to significantly decrease the risk of producing IAN injury.

Inferior alveolar nerve sensory disturbance after impacted mandibular third molar evaluation using cone beam computed tomography and panoramic radiography: a pilot study.

PURPOSE: To measure sensory disturbances of the inferior alveolar nerve (IAN) after removal of impacted mandibular third molars using cone beam computed tomography (CBCT) and dental panoramic radiography (PAN) for preoperative assessment in a randomized controlled trial and to measure the efficacy of the observers' prediction of IAN exposure at surgery based on CBCT compared with PAN. MATERIALS AND METHODS: The sample consisted of 86 impacted third molars (from 79 consecutive patients) in close relation to the IAN as determined by PAN and judged as showing a "moderate" risk of IAN damage. Cases presenting with no close relation between the IAN and roots and extremely risky cases with an obvious interrelation were excluded. Potential neurosensory disturbances of the lip and chin were assessed before surgery and during the postoperative recall by measuring the function of the IAN with the light-touch sensation method. RESULTS: Postoperative sensory disturbances occurred in 1 patient in the CBCT group and 1 patient in the PAN group. The light-touch sensation test showed no significant differences at the lip (P = .10) and chin (P = .17) levels for CBCT- versus PAN-based surgery. Significant differences in making a correct diagnosis of neurovascular bundle exposure at the extraction of impacted teeth were found between the 2 modalities (P = .029). CONCLUSIONS: Within the limits of the present pilot study, CBCT was not superior to PAN in predicting postoperative sensory disturbances but was superior in predicting IAN exposure during third molar removal in cases judged as having "moderate" risk.

Pericoronal ostectomy: an alternative surgical technique for management of mandibular third molars in close proximity to the inferior alveolar nerve.

PURPOSE: Close proximity of the inferior alveolar nerve (IAN) to mandibular third molars (MTMs) may result in nerve injury during the extraction of third molars. Alternative surgical techniques, such as coronectomy, have been suggested to decrease this risk. This study examined a new alternative technique, the pericoronal ostectomy (PO), that is intended to decrease IAN injury in high-risk cases. PATIENTS AND METHODS: This prospective clinical cohort study consisted of 14 patients with 17 MTMs in close relation to the IAN. All patients were subjected to 2- and 3-dimensional preoperative radiographic evaluations. Selected patients with mesioangular and vertical bone impactions were treated by the staged PO technique. An institutional review board approval from the University of the Pacific was given to this study. RESULTS: Because of the PO procedure, all 17 high-risk MTMs in the study erupted to a more occlusal position away from the danger zone of the IAN and were eventually removed (mean distance of eruption, 2.0 mm). Three patients reported a transient neurosensory deficit, 2 with the IAN and 1 with a lingual nerve. All 3 had a full resolution of symptoms within 3 months of the postoperative period. CONCLUSION: The PO technique appears to be an additional viable alternative technique to extraction of MTMs in intimate proximity to the IAN.

3-Dimensional imaging for lower third molars: is there an implication for surgical removal?

PURPOSE: Surgical removal of impacted third molars may be the most frequent procedure in oral surgery. Damage to the inferior alveolar nerve (IAN) is a typical complication of the procedure, with incidence rates reported at 1% to 22%. The aim of this study was to identify factors that lead to a higher risk of IAN impairment after surgery. MATERIALS AND METHODS: In total 515 surgical third molar removals with 3-dimensional (3D) imaging before surgical removal were retrospectively evaluated for IAN impairment, in addition to 3D imaging signs that were supposed predictors for postoperative IAN disturbance. Influence of each predictor was evaluated in univariate and multivariate analyses and reported as odds ratio (OR) and 95% confidence interval (CI). RESULTS: The overall IAN impairment rate in this study was 9.4%. Univariate analysis showed narrowing of the IAN canal (OR, 4.95; P < .0001), direct contact between the IAN and the root (OR, 5.05; P = .0008), fully formed roots (OR, 4.36; P = .045), an IAN lingual course with (OR, 6.64; P = .0013) and without (OR, 2.72; P = .007) perforation of the cortical plate, and an intraroot (OR, 9.96; P = .003) position of the IAN as predictors of postoperative IAN impairment. Multivariate analysis showed narrowing of the IAN canal (adjusted OR, 3.69; 95% CI, 1.88 to 7.22; P = .0001) and direct contact (adjusted OR, 3.10; 95% CI, 1.15 to 8.33; P = .025) to be the strongest independent predictors. CONCLUSION: Three-dimensional imaging is useful for predicting the risk of postoperative IAN impairment before surgical removal of impacted lower third molars. The low IAN impairment rate seen in this study-compared with similar selected study groups in the literature of the era before 3D imaging-indicates that the availability of 3D information is actually decreasing the risk for IAN impairment after lower third molar removal.

Histology and intramandibular course of the inferior alveolar nerve.

The morphology of the inferior alveolar nerve is a very important factor for all surgical procedures in the mandibular region. The aim of this anatomical and histological study was to describe the intramandibular course and the microscopic histology of the inferior alveolar nerve in the dissected human cadaver. Twenty partially dentulous hemimandible specimens from human cadavers were dissected and embalmed, and the findings were interpreted by standard and histological imaging. The result of this study showed that the inferior alveolar nerve comprises two larger nerves that are separately wrapped in perineural sheaths and spirally twisted around each other. The mental nerve exits through the mental foramen in the premolar region and the dental nerve continues from the premolar region as the incisive nerve in the incisive canal. These findings provide relevant data for clinical dentistry, especially when planning oral and dental operative treatment procedures in the mandibular region.

Surgical extraction of impacted inferior third molars at risk for inferior alveolar nerve injury.

The objective of the study was to prospectively assess the intraoperative findings and the radiographic signs of a study population of patients with impacted third molars at risk of inferior alveolar nerve injury. One hundred thirty-four patients with impacted mandibular third molars at risk for nerve injury were included in the study. Radiographic signs of possible close relationship between the 2 structures and intraoperative exposition or damage of the inferior alveolar nerve were recorded. The follow-up controls comprised clinical examinations and assessment for the sensation of the lower lip and chin. In 24 patients, a real contiguity was encountered between the third molars and nerve. Among these, intraoperative neural exposition was observed in 19 patients. Four patients complained of postoperative temporary hypoesthesia. No deficit of sensibility was found in cases with no exposition of the nerve. The accidental exposition of the inferior alveolar nerve is associated with an increased risk for neural injuries. At panoramic radiograph, the presence of signs of bifid and radiolucent apex, superimposition, and radiolucent root band should be considered at high risk for neural damage.

Lingual nerve morbidity and mandibular third molar surgery: a prospective study.

OBJECTIVE: The objective of this study was to estimate the frequency of postoperative lingual nerve (LN) impairment after the surgical removal of mandibular third molars (M3) and to identify potential risk indicators. SUBJECTS AND METHODS: A prospective cohort study involving 321 subjects who had 443 mandibular M3 surgically extracted at the University Hospital, Amman, Jordan. Predictor variables were categorized as patient-, anatomy- and operation-specific. The outcome variable was the presence or absence of LN impairment. Bivariate and multivariate analyses were performed to identify independent predictors. RESULTS: The prevalence of temporary LN hypoesthesia was 2.5% and all 11 cases resolved within 6 months. Factors that predicted LN injury by univariate analysis were horizontal and mesioangular tooth angulation, bone removal, tooth sectioning, longer operations, lingual flap retraction and bleeding into the socket. In the multivariate logistic regression model, lingual flap retraction (p = 0.002, OR = 26.790) and bleeding into the socket (p = 0.044, OR = 4.918) were the independent predictors. CONCLUSION: Operative variables were the main predictors of temporary LN damage.

[Bifid and trifid mandibular canal. A coincidental finding]. / Canalis mandibulae bifidus en trifidus. Een toevalsbevinding.

A 26-year-old man was suffering from pericoronitis of his mandibular third molars. To determine the position of the mandibular canal in relation to the roots of the third molars, a panoramic radiograph was made. The radiograph revealed at the right side a bifid mandibular canal and the upper part of the canal seemed to be related to the third molar. Additionally, a cone beam CT was made, which revealed a bifid mandibular canal at the left side and a trifid mandibular canal at the right side. Anatomical anomalies of the mandibular canal may have clinical implications, such as an increased risk of injury to the inferior alveolar nerve in case of removing a mandibular third molar and inadequate local anesthetics.

A preferable technique for protecting the inferior alveolar nerve: coronectomy.

PURPOSE: The aim of this study was to evaluate the effectiveness of coronectomy for teeth whose root apices are very close to the inferior alveolar canal. PATIENTS AND METHODS: The 43 patients of this study needed removal of their lower third molar, whose root apices were very close to the inferior alveolar canal. These patients underwent 47 coronectomies. RESULTS: The mean follow-up period was 9.3 months (range, 1 to 48 months). The mean total amount of root movement was 3.4 mm at 6 months, 3.8 mm at 12 months, and 4.0 mm at 24 months. CONCLUSIONS: The technique of coronectomy is defined as removing the crown of a tooth but leaving the roots untouched, so that the possibility of nerve damage is reduced. Coronectomy is a preferable technique for patients who run a risk of injury to the inferior alveolar nerve during third molar surgery.

Influence of the tooth section technique in alveolar nerve damage after surgery of impacted lower third molars.

This study is a randomized control split-mouth non-blinded prospective trial, the aim of which was to evaluate clinically the frequency and type of injury to the inferior alveolar nerve (IAN) following mandibular third molar surgery using or not using the tooth section technique. The sample consisted of 50 lower third molars in 25 patients, in the control group the tooth section technique was not used, and it was used in the experimental group. The outcomes have shown a frequency of 8% of IAN injury for both groups (in both genders), and there were no statistically significant associations between the use of the tooth section technique and a diminished incidence of IAN injury or the presence of radiographic signs of a direct relationship between the tooth/nerve/mandibular canal and IAN injury. There was no association between deformities of the tip of dental needles and nerve injury. Temporary hypoesthesia and paresthesia were the commonest nerve injuries. All patients recovered from these injuries within six months.