The Management of a Geriatric Patient Using Dabigatran Therapy on Dentigerous Cyst with Oral Bleeding

Jaw cysts represent a great matter of interest in oral and maxillofacial surgery. Jaw cyst surgery is a common intervention in oral surgery but, in the case of a multidisciplinary patient, the oral surgeon needs to meet with other specialists. A cyst is an epithelium-lined sac containing fluid and/or semisolid material due to epithelial cell proliferation, degeneration, and liquefaction; the hypertonic solution withdraws liquids from the surrounding tissues, while internal pressure exerts an equal strength on the cyst walls. Dentigerous cysts are the second most common odontogenic cysts after radicular cysts, and commonly few or no symptoms are reported. However, the most common diagnosis for dentigerous cyst is represented by eruption of the affected tooth or accidental diagnosis. Commonly, dentigerous cysts may be related to impacted third molars; in the case of impacted third molars and a dentigerous cyst, the tooth should be removed along with the cyst in the same intervention. Mandibular dentigerous cysts are common in children and adults, while dentigerous cysts are a rare neoformation in elderly patients. Treatment usually involves removal of the entire cyst and the associated unerupted tooth. This intervention may be more difficult if the cyst is large, the third molar is in contact with the mandibular nerve, and/or the patient has a medical history that may represent a relative or absolute contraindication. We present the case of a rare symptomatic manifestation of dentigerous cyst in an elderly patient in treatment with dabigatran therapy; for the treatment of dentigerous cysts in the elderly, we suggest a multidisciplinary approach with the use of the histological examination and a careful follow-up.

Neurosensory Deficits of the Mandibular Nerve Following Extraction of Impacted Lower Third Molars-A Retrospective Study

BACKGROUND

Neurosensory deficits are one of the major complications after impacted lower third molar extraction leading to an impaired patient's quality of life. This study aimed to evaluate the incidence of neurosensory deficits after lower third molar extraction and compare it radiologically to the corresponding position of the inferior alveolar nerve.

METHODS

In a retrospective study, all patients who underwent impacted lower third molar extraction between January and December 2019 were compiled. Therefore, clinical data as well as preoperative radiological imaging were assessed.

RESULTS

In total, 418 patients who underwent lower third molar extractions (n = 555) were included in this study. Of these, 33 (5.9%) had short-term (i.e., within the initial 7 postoperative days) and 12 (1.3%) long-term (i.e., persisting after 12 months) neurosensory deficits documented. The inferior alveolar nerve position in relation to the tooth roots showed apical position in 27%, buccal position in 30.8%, lingual position in 35.4%, and interradicular position in 6.9%.

CONCLUSIONS

A statistically significant increased incidence of neurosensory deficits occurs when the inferior alveolar nerve is directly positioned lingually to the tooth roots (p = 0.01).

The surgical anatomy of the inferior alveolar nerve: a meta-analysis with clinical implications

BACKGROUND

The main goal of the present meta-analysis was to provide physicians, especially surgeons, with crucial data on the complete anatomy of the inferior alveolar nerve (IAN). It is hoped that our results may help reduce the rates of complications in procedures associated with this anatomical entity.

MATERIALS AND METHODS

Major online medical databases such as PubMed, Embase, Scopus, Web of Science, Google Scholar, and Cochrane Library were searched to gather all studies on IAN anatomy, including topography, morphology, and variations.

RESULTS

IAN mean thickness of the IAN in the mandibular angle area was set to 2.32 mm (LL: 1.82 ; HL: 2.78-). IAN mean thickness of the IAN in the mandibular body region was found to be 2.49 mm (LL: 2.02 ; HL: 2.98). The mean thickness of the IAN in the mental region was established at 1.70 mm (LL: 1.54 ; HL: 1.86). The mean distance from the IAN to the external (buccal) surface of the 1st molar was set to be 4.99 mm (LL: 3.84 ; HL: 6.13).

CONCLUSIONS

In conclusion, this is the most up-to-date and thorough analysis of the complete anatomy of the IAN. We provided morphometric data that present the spatial relationship of the IAN with numerous anatomical landmarks in the mandibular region. These include the ramus of the mandible, the first, second, and third molars, and the body of the mandible, among others. It is hoped that the results of the present meta-analysis may be a helpful tool for physicians, especially surgeons, performing various oral and maxillofacial procedures, such as third molar removal or IAN block anesthesia.

The relationship between the auriculotemporal nerve and middle meningeal artery in a sample of the South African population

BACKGROUND

The interaction between the auriculotemporal nerve and the middle meningeal artery within the infratemporal fossa is vital in the spread of perineural tumours. Knowledge of their morphological and morphometric variations is critical to surgeons approaching the infratemporal fossa. There is a paucity of literature on the relationship between the auriculotemporal nerve and middle meningeal artery in a South African population. Hence, the aim of this study was to document the morphology and morphometry of the auriculotemporal nerve and its relationship to the middle meningeal artery within a South African cohort.

MATERIALS AND METHODS

The infratemporal fossae of 32 cadaveric specimens were dissected and the auriculotemporal nerves and middle meningeal arteries were analysed, together with their variations.

RESULTS

Nine out of 32 specimens displayed one-root, 14/32 two-root, 7/32 three-root, and 2/32 four-root auriculotemporal nerves. Eighteen auriculotemporal nerves originated from the mandibular nerve, while the rest had at least one communication to the inferior alveolar nerve. The mean distance between the first and second roots of the auriculotemporal nerve was 4.69 mm. There were V-shaped formations found in 23 auriculotemporal nerves. However, the middle meningeal artery only passed through 13/23 V-shapes. The maxillary artery was of a deep course in relation to the lateral pterygoid muscle in 19/32 and superficial in 13/32 of the sample. There were 15 accessory middle meningeal arteries present in 14/32 specimens. The accessory middle meningeal arteries often arose from the middle meningeal artery (46.67%).

CONCLUSIONS

The results of this study show a high possibility of variations of the auriculotemporal nerve and middle meningeal artery in the South African population. The variations and interactions should be considered during surgical procedures.

Evaluation of the Anatomic Position of the Mandibular Canal Regarding to the Segments of the Mandibular Sagittal Split Ramus Osteotomy to Diminish the Possibility of Injuries: a Pilot Study

Objectives

This pilot study evaluated the relationship between inferior alveolar nerve location through computed tomography scan and intraoperative inferior alveolar nerve entrapment after bilateral sagittal split osteotomy.

Material and Methods

Overall, 20 helicoidal computed tomography scans were evaluated in patients with facial deformities who underwent to bilateral sagittal split osteotomy (BSSO). The distance from the mandibular canal to the internal surface of the buccal and lingual cortical bone, mandibular thickness, bone density and proportion of medullary and cortical bone in 3 regions were evaluated. During the intraoperative period, the segment to which the nerve remained adhered after performing BSSO was analysed, and the data correlated.

Results

The distance from the mandibular canal to the buccal cortical bone showed a mean of 2.6 mm when the inferior alveolar nerve was adhered to the distal segment and mean of 0.7 mm when the nerve was adhered to the proximal segment. The thickness was 11.2 mm and 9.8 mm when the nerve was adhered the distal the proximal segments respectively. Mandibular thickness, distance from the mandibular canal to the buccal and lingual cortical were statistically related to intraoperative nerve entrapment (P < 0.05).

Conclusions

Narrow jaws and the distance from the mandibular canal to buccal cortical bone less than 2 mm increases the risk of the inferior alveolar nerve entrapment in bilateral sagittal split osteotomy.

Numb Chin Syndrome in Sickle Cell Disease: A Systematic Review and Recommendations for Investigation and Management

Numb chin syndrome (NCS) is a rare sensory neuropathy resulting from inferior alveolar or mental nerve injury. It manifests as hypoesthesia, paraesthesia, or, rarely, as pain in the chin and lower lip. Several case reports suggest that sickle cell disease (SCD) could be a cause of NCS. However, information about NCS is scarce in this population. Our objectives were to synthesize all the available literature relevant to NCS in SCD and to propose recommendations for diagnosis and management based on the best available evidence. A systematic review was performed on several databases to identify all relevant publications on NCS in adults and children with SCD. We identified 73 publications; fourteen reports met the inclusion/exclusion criteria. These described 33 unique patients. Most episodes of NCS occurred in the context of typical veno-occlusive crises that involved the mandibular area. Radiological signs of bone infarction were found on some imaging, but not all. Neuropathy management was mostly directed toward the underlying cause. Overall, these observations suggest that vaso-occlusion and bone infarction could be important pathophysiological mechanisms of NCS. However, depending on the individual context, we recommend a careful evaluation to rule out differential causes, including infections, local tumors, metastatic disease, and stroke.

A systematic compendium of turtle mandibular anatomy using digital dissections of soft tissue and osteology

Turtles are a charismatic reptile group with a peculiar body plan, which most notably includes the shell. Anatomists have often focused descriptive efforts on the shell and other strongly derived body parts, such as the akinetic skull, or the cervical vertebrae. Other parts of turtle osteology, like the girdles, limbs, and mandibles, are documented with less rigor and detail. The mandible is the primary skeletal element involved in food acquisition and initial food processing of turtles, and its features are thus likely linked to feeding ecology. In addition, the mandible of turtles is composed of up to seven bones (sometimes fused to as little as three) and has thus anatomical complexity that may be insightful for systematic purposes and phylogenetic research. Despite apparent complexity and diversity to the mandible of turtles, this anatomical system has not been systematically studied, not even in search of characters that might improve phylogenetic resolution. Here, we describe the mandibular osteology for all major subclades of extant turtles with the help of digitally dissected 3D models derived from high-resolution computed tomography (μCT) scans of 70 extant species. We provide 31 fully segmented mandibles, as well as 3D models of the mandibular musculature, innervation, and arterial circulation of the cryptodire Dermatemys mawii. We synthesize observed variation into 51 morphological characters, which we optimize onto a molecular phylogeny. This analysis shows some mandibular characters to have high systematic value, whereas others are highly homoplastic and may underlie ecological influences or other factors invoking variation.

Inferior alveolar nerve injury due to the extrusion of calcium hydroxide during endodontic treatment: A case report

Although many materials are used for root canal fillings in endodontic treatment, calcium hydroxide has been preferred for many years due to its bactericidal effect and biocompatibility. Calcium hydroxide can be applied in more than one form. In this case study, calcium hydroxide in viscous form, applied into the root canal during endodontic treatment, overflowed from the apical part of the tooth to the inferior alveolar nerve canal. Postoperative paraesthesia was observed in the patient. Dental volumetric tomography was performed to study the extent of sealer in the inferior alveolar nerve canal. Considering the short resorption time of the calcium hydroxide paste, no surgical intervention was performed on the patient. After 6 months, the root canal material was completely resorbed, and paraesthesia decreased. At the 3-year follow-up, the patient's paraesthesia had completely disappeared.

Trigeminal nerve injuries. Four years' experience at a single Argentine referral center and a literature review

The aim of this retrospective study was to describe the etiology and characteristics of trigeminal nerve injuries referred to a specialized center in Buenos Aires, Argentina. A retrospective analysis was performed of patients referred from February 2016 to January 2020. Age, sex, intervention performed, nerve affected, time elapsed from injury, diagnosis, location, and whether patient had signed informed consent were recorded. A descriptive analysis of the data was made, and 95% confidence intervals were calculated for prevalence. The study sample consisted of 30 subjects (31 nerve injuries), 19 female and 11 male, average age (±SD) 40 ± 17 years. The inferior alveolar nerve was the most frequently injured nerve (74%,) while the lingual nerve accounted for 26%. The most common etiologies were inferior molar extractions (47%), dental implants (20%), and local anesthesia (13%). Other etiologies were autologous mandibular bone grafts for dental implants, removal of cysts associated with the inferior third molar, and endodontic treatment. Dental Institutions at which treatment was provided were found to be significantly associated with patients being warned and asked to sign informed consent (p<0.05), while dentists working at private offices requested fewer consents. The most frequent symptom was paresthesia, and 5 patients suffered spontaneous or evoked pain. Only 2 patients intended to file legal claims. Dentists should be aware of the debilitating effects resulting from trigeminal injuries, the complexity of their resolution and the importance of carefully planning dental procedures to prevent them.

Correlation between the Mandibular Lingula Position and Some Anatomical Landmarks in Cone Beam CT

Background: the position of the mandibular lingula (Li) affects the success rate of the inferior alveolar nerve block (IANB) and ramus osteotomies. This study evaluated the position of the Li, to investigate the anatomical relationship between the Li and some anatomical measurements using cone beam computed tomography (CBCT). Methods: 201 hemimandibular CBCTs of 111 patients (43 males and 68 females; 18 to 88 years old) were retrospectively evaluated. The Li location was determined from the lingula tip to: the occlusal plane, the anterior and posterior borders of the mandibular ramus, the lower border of the mandible, the distal surface of the mandibular second molar, and the mandibular notch. We evaluated the correlations between the Li and the anteroposterior diameter of the mandibular ramus; the vertical distance between condyle and mandibular angle; the mesial–distal diameter of the first, second, and third mandibular molar, the intercanine distance, the intermolar distances among the first, second, and third mandibular molars; the distance between the intermolar line of the first molar and midline, and the length of the mandibular body. Results: the vertical distance of the Li from the occlusal plane was 11.22 ± 4.27 mm. Some parameters significantly correlated with the anatomical measurements taken into consideration. Conclusions: the present study provides new information concerning the Li and mandibular anatomy in the Italian population. Moreover, by correlating some anatomic measurements to the Li position, the localization of the Li is made possible, indirectly through the measurement of some distances between anatomical landmarks.

Assessment of Anatomical Variations of Mandibular Canal Depicted in Panoramic Radiography

BACKGROUND

Anatomical variations of the mandibular canal play a vital role while performing surgical procedures affecting an area with mandibular canal course in the mandible. The neurovascular bundle may be severed during surgical procedures carried out mandible.

AIMS AND OBJECTIVES

The present retrospective study was aimed to assess and evaluate the mandibular canal and its variations on the panoramic radiography.

MATERIALS AND METHODS

The study included 88 randomly selected panoramic radiographs with complete mandible and associated bone. On a panoramic radiograph, the following parameters were assessed including bifid mandibular canal and location of bifurcation, the diameter of the mandibular canal as recorded in the first molar region, trabeculation in submandibular gland fossa, anterior loop measurement, direction and diameter of the bifid mandibular canal were all evaluated. Statistical analysis was done.

RESULTS

In 51 hemimandibles, the mandibular canal was found to be corticalized, whereas in 21.59% (n = 19), the mandibular canal was visible. In the remaining 20.45% (n = 18) of the study participants, the mandibular canal was not visualized. In the submandibular gland fossa region, diminished trabeculation was seen in 55.68% of the evaluated radiographs, whereas trabeculation was not seen at all in the remaining 23.86% of the subjects. A significant correlation was seen in decreased trabeculation of submandibular gland fossa and absence of the mandibular canal (P value < 0.001). The bifid mandibular canal was seen in 19.31% of the study participants (n = 17) with a mean width of 3.12 ± 1.1 mm. Extension of the anterior loop of the mental nerve was seen as up to 2 mm in majority participants in 67.04% individuals (n = 59).

CONCLUSION

The present study suggests that panoramic radiographs are a reliable tool for assessment of the mandibular canal and associated anatomical variations associated with it.

Comparative Evaluation of Classical Inferior Alveolar Nerve Block and Gow-gates Nerve Block for Surgical Removal of Mandibular Third Molar: A Prospective Study

BACKGROUND

The most commonly used nerve block procedure to anesthetize the mandibular arch is the classical inferior alveolar nerve block (IANB). In 1973, Gow-Gates developed a new procedure known as the Gow Gates nerve block, to achieve anesthesia in the same area with fewer complications.

METHODOLOGY

The study comprised 80 patients who reported for the surgical removal of impacted third molar. The patients were randomly assigned into two groups- Group I received Gow-gates nerve block and Group II were administered classical IANB. Positive aspiration, meantime for the onset of anesthesia, mouth opening before and after each block and pain during the surgical procedure were compared.

RESULTS

Group 1 yielded positive aspiration in 2.5% of the cases (one patient) and 15% had positive aspiration in Group 2 (six patient). The mean time taken for onset of anesthesia was 6.16 min in Group 1 as compared to 2.78 min in Group 2. While comparing the quality of anesthesia between the blocks, 87.5% of the patients in Group 1 and Group 2 had successful anesthesia equally i.e., 35 of the 40 patients fell into category 1 and 2 of the eight-point category rating scale in both the groups and the remaining five patients (12.5%) in both the groups had unsuccessful anesthesia.

CONCLUSION

Both approaches offer quality anesthesia in the posterior mandibular area when meticulously followed. The percentage of unsuccessful anesthesia in the Gow-Gates group could be attributed to the inexperience of the operator. Postoperative comfort and patient satisfaction were greater in the other group.

Variant Innervation of the Medial Pterygoid Muscle from the Lingual Nerve

During a routine dissection of the infratemporal fossa and lateral face, a branch of the left lingual nerve was observed entering the medial pterygoid muscle. Normally, the nerve to the medial pterygoid is a direct branch from the mandibular nerve, with no communications with the lingual nerve. There are many reports involving variations of the mandibular nerve; however, few reports describe lingual nerve variations involving the medial pterygoid muscle. Reconstructive surgeries for cosmesis and trauma, tumor excision, and impacted third molar removal may all damage the lingual nerve and might, as seen in the present case, affect the medial pterygoid muscle. Given the presumed rarity of this variation, we discuss the possible embryological origins as well as the surgical conflicts that may arise with this type of variation.

Tomographic evaluation of the mandibular nerve in the mental region and its surgical implications: a cross-sectional study

The aim of this study was to evaluate the prevalence and length of the anterior loop (AL) of the inferior alveolar nerve, nerve emergence from the mental foramen, and prevalence of sensory disorders after implant placement in the interforaminal region. Four hundred and fifty hemimandibles (225 patients) were evaluated using cone beam computed tomography and panoramic radiographs. Information on the presence of sensory disorders was obtained from the medical records. AL prevalence was 13.6% and mean AL length was 1.25 mm. The false-negative rate for the identification of the AL using panoramic radiography was 58.6%. Straight nerve emergence from the mental foramen was the most prevalent (62.7%), followed by anterior (21.8%) and posterior (15.6%) emergence. The incidence of sensory disorders was 4.4%, and 1.1% were related to the presence of the AL. When implants were placed within the planned distance of the mental foramen or further, 1.2% had sensory problems associated with the presence of the mandibular incisive canal. In cases of distances smaller than planned, 12.9% had sensory alterations. Only five (1.1%) had the AL, with a length between 0 and 4.5 mm. However, in four cases, the planned distance was respected and, even so, there was a sensory disorder. Posterior nerve emergence from the mental foramen was associated with a higher prevalence of AL.

A Randomized Observer-Blinded Controlled Trial to Compare Pre-Emptive with Postoperative Ultrasound-Guided Mandibular Nerve Block for Postoperative Analgesia in Mandibular Fracture Surgeries

Background and Aims

Ultrasound-guided (UG) mandibular nerve block is effective for providing postoperative analgesia in mandibular fracture surgeries. The pre-emptive nerve blockade prolongs the duration of postoperative analgesia and reduces the consumption of intraoperative opioids. The aim of this prospective, randomized, single-blinded study was to compare the efficacy of pre-emptive and postoperative UG mandibular nerve block for postoperative analgesia in mandibular fracture surgeries.

Methods

Sixty patients scheduled for unilateral mandibular fracture surgeries were randomly divided into two groups by computer-generated random numbers and sealed envelope method: Group A received UG mandibular nerve block before surgical incision and group B received after surgery with ropivacaine 0.5% 10mL. The second anesthesiologist, who was blinded to the group involved, monitored the patient. The patients as well as the statistician were also blinded. The patients were started on patient-controlled analgesia (PCA) morphine with bolus 1mg and a lockout interval of 10min. The morphine consumption for 24h was recorded. The pain was assessed by the VAS score. The additional intraoperative fentanyl consumption and time for a request for rescue analgesic were recorded.

Results

The total morphine consumption was reduced in group A (4.566±0.717mg) than group B (5.93±0.876mg) with a p-value of <0.0001. The time for a request for rescue analgesic was also prolonged in group A (794.08±89.561min) than group B (505.333±3.159min). In group A, only four patients required an additional dose of fentanyl as against 11 patients in group B. The heart rate was also lower in group A 30min after the administration of the block and persisted for two hours intraoperatively.

Conclusion

Pre-emptive ultrasound-guided mandibular nerve block reduces morphine consumption, prolongs the time for a request for rescue analgesic, reduces intraoperative fentanyl consumption, provides better control of intraoperative heart rate, and better pain scores postoperatively when compared to the postoperative mandibular nerve block.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/0ifMIJ8ooiU

Mandibular nerve block in juvenile Nile crocodile: a cadaveric study

OBJECTIVE

To develop a technique for performing the mandibular nerve block in Nile crocodiles.

STUDY DESIGN

Experimental cadaveric study.

ANIMALS

A total of 16 juvenile Nile crocodile heads.

METHODS

To study the course of the mandibular nerve, one head was dissected. Computed tomography (CT) examination was performed in two heads to identify useful landmarks. Thereafter, a hypodermic needle was inserted through the external mandibular fenestra of 17 hemimandibles (13 heads), and a mixture of methylene blue and iohexol was injected. Injection volumes were 0.5 (n = 7) and 1.0 mL (n = 10) for hemimandibles < 15 and ≥ 15 cm long, respectively. Iohexol spread and nerve staining with methylene blue were assessed with CT and anatomical dissection, respectively. Data were analysed with one-sample t test or Mann-Whitney U test. Significance was set at p < 0.05.

RESULTS

Both anatomical dissection and imaging confirmed the external mandibular fenestra as a useful anatomical landmark for needle insertion. The CT images acquired after needle positioning confirmed that its tip was located on the medial bony mandibular surface formed by the fusion of the angular and coronoid bones in 100% cases. In all the hemimandibles, the rostrocaudal spread of contrast was > 23 mm. The length of the stained mandibular nerve in the temporal region and of the stained medial branch of the mandibular nerve, as well as the dorsoventral and mediolateral spread of iohexol, was greater in group 1.0 than in group 0.5 (p < 0.001). The caudal spread of iohexol was greater in group 1.0 than in group 0.5 (p = 0.01).

CONCLUSIONS AND CLINICAL RELEVANCE

The technique developed in this study is feasible. Both injection volumes resulted in staining of the mandibular nerve. The spread of contrast in the anatomical region of interest may result in successful sensory block.

The effect of systemic rifampicin treatment on inferior alveolar nerve regeneration in rats following crush injury

Axonal regeneration of the inferior alveolar nerve (IAN) is a therapeutic target for functional recovery after peripheral nerve injury. Rifampicin exerts anti-apoptotic, anti-inflammatory, and anti-oxidant effects on nerve tissues that may enhance functional recovery after peripheral nerve injury. The aim of the present study was to evaluate the therapeutic effects of systemic rifampicin following IAN crush injury. Following the nerve crush injuries of the IAN, 24 Sprague-Dawley rats were randomly divided into three groups to receive daily intraperitoneal injections of either vehicle, 5 mg kg^-1 rifampicin, or 20 mg kg^-1 rifampicin. Twenty-four days after induction of nerve injuries, Fluorogold (FG) was injected over the mental foramen for the evaluation of neuronal survival. At the end of the four-week period, histologic and histomorphometric examination of IAN samples were performed and FG positive cells were counted in the trigeminal ganglion sections. FG positive cells were significantly more frequent in the 20 and 5 mg kg^-1 rifampicin groups than in the vehicle-treated group. Electron microscopic analyses revealed that the percentage of axons with optimum g-ratio was significantly lower in the vehicle group than in both treatment groups. In conclusion, systemic rifampicin treatment can enhance peripheral nerve regeneration.

Comparison of Conventional Techniques and Higher Imaging Modalities in the Evaluation of Relation between the Third Molar and Inferior Alveolar Nerve Canal: A Pilot Study

Context:

Mandibular third molars are the most commonly impacted teeth, and their surgical removal can be associated with inferior alveolar nerve (IAN) injury. To avoid the deleterious complication of nerve injury on patients, a thorough visualization of IAN and its localization are essential.

Aims and Objectives:

The aims and objectives of this study were to evaluate the efficacy of two conventional localization techniques in determining the relationship of mandibular third molars to IAN and to assess its reliability in comparison with computed tomography (CT).

Settings and Design:

Panoramic radiograph (PR) was taken using Kodak 8000C Digital Panoramic and Cephalometric system. Intraoral periapical radiographs (IOPAs) were taken using Kodak 2200 Intraoral X-ray machine. CT scan images were taken using multidetector CT scans.

Materials and Methods:

Two IOPAs (0° and −20° vertical angulation) and PR and CT scan images of thirty mandibular third molars were taken. Two combinations were used (i) a combination of two IOPAs and (ii) a combination of PR and IOPA (−20°). Tube-shift localization technique was applied to both these combinations to derive the relation between third molar and IAN canal as “in contact,” “separate,” “buccal,” “lingual,” and “in line with the apex” and the results were compared with CT images.

Statistical Analysis:

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated using SPSS software version 15.0.

Results:

The combination of PR and IOPA radiographs showed 14 teeth to be in contact with IAN. This gave a sensitivity of 100%, specificity of 94.1%, PPV of 92.9%, and a NPV of 100% in determining the relation as “in contact” or “separate.” 78.3%, 85.7%, 94.7%, and 54.5% were the sensitivity, specificity, PPV, and NPV in localizing it as “buccal,” “lingual,” or “in line with apex.” These results were better than that of the combination of the two IOPAs.

Conclusions:

Localization using PR and IOPA could better deduce the relation between IAN and mandibular third molar.

Evaluation of the effect of the inversion filter on enhancing the visibility of the mandibular incisive canal in comparison with the original images

BACKGROUND

The mandibular incisive canal (MIC) is a neural canal containing one of the lower branches of the inferior alveolar nerve, called the mandibular incisive nerve, which can get damaged and cause complications during the removal of bone from the interforaminal region.

OBJECTIVES

The aim of this study was to determine the effect of the inversion filter (IF) on improving the visibility of MIC as compared to the original images.

MATERIAL AND METHODS

In this retrospective, descriptive, analytical study, 343 samples of digital panoramic radiography were examined. The images were analyzed with and without IF. The frequency and confidence intervals (CIs) of identifying MIC were used to determine its visibility, both with IF and in the original images. Besides, the difference between the maximum and minimum diameters of the canal as well as the distance from MIC to the alveolar crest and to the mental foramen were examined. For statistical analysis, McNemar's test and the paired t-test were used, and the concordance was calculated using the kappa coefficient.

RESULTS

No significant differences were found in the prevalence of the incisive canal, or in its unilateral or bilateral visibility between the original and filtered radiography in this study (p = 0.42 and p = 0.67, respectively). The absolute values of the interval difference between MIC and the mental foramen, the maximum and minimum diameters of MIC, and the distance from MIC to the alveolar crest were statistically significant between the filtered and original radiography, although the difference was clinically unimportant.

CONCLUSIONS

The use of IF produced results similar to the original radiography; its application neither increased the clarity nor improved the visibility of the incisive canal.

Double mandibular canal and triple mental foramina: detection of multiple anatomical variations in a single patient

Having complete information about a patient's mandibular canal and mental foramen is fundamental to performing safer procedures and avoiding intraoperative and postoperative complications. Cone beam computed tomography (CBCT) produces accurate images for the analysis of maxillomandibular bone structures and is widely used in dentistry. The aim of this study is to report a case of mandibular bifid canal associated with triple mental foramina that was revealed with CBCT images. A 45-year-old woman was referred for a CBCT scan of remaining bone quantity to assist in preoperative implant planning. The patient had reported problems related to anesthesia during extraction of the mandibular right second and third molars. Examination showed bilateral bifurcation of the mandibular canal, from the mandibular foramen to the gonial angle. In addition, exteriorization of the mandibular canal was noticed in 3 regions; that is, there were 3 distinct mental foramina. Clinicians must be aware of these anatomical variations in the mandibular region during dental procedures to avoid complications such as difficulty in obtaining anesthesia or postoperative sensory dysfunction.

Bipolar radiofrequency ablation of mandibular branch for refractory V3 trigeminal neuralgia

Background: Percutaneous trans-foramen ovale (FO) radiofrequency ablation (RFA) of Gasserian ganglion (GG) is commonly used to treat V3 trigeminal neuralgia (TN). However, this intracranial approach is less selective and safe.

Objectives: To report a novel percutaneous within-FO RFA of the V3 under CT-guidance and outcomes with both bipolar and monopolar techniques.

Patients and methods: Twenty-six patients with isolated V3 primary TN and FO >6 mm in diameter underwent either monopolar (n=12) or bipolar RFAs (n=14) based on their preference. Successful analgesia over V3, residual pain, recurrent pain, and complications were compared between the two groups. The ex vivo egg albumen model was used to demonstrate the size difference in the thermocoagulation lesion created by monopolar vs bipolar electrodes.

Results: In the bipolar group, there were more cases of masticatory atonia as compared to the monopolar (P=0.104), but no residual pain was observed. In the monopolar group, there were two cases of residual pain found, which led to immediate repeat RFAs. Therefore, during the immediate post-operative period, both groups obtained 100% complete V3 analgesia with a similar risk of facial hematoma (P=0.641). During up to 27-months of post-operative follow-up, in the bipolar group, complete pain relief persisted in all patients; in the monopolar group, 1 case of recurrent pain was found at 14 months. Ex vivo study demonstrated that, at 90 °C/90 seconds of RFA, the width of lesions is significantly larger by the 6-mm spacing parallel-tip bipolar electrodes compared to the monopolar electrode (9.5±0.567 vs 5.5±0.07 mm).

Conclusion: In treating patients with isolated V3 TN and FO >6mm in diameter, this percutaneously within-FO RFA of the V3 under CT guidance is both clinically practical and effective, while bipolar RFA is associated with a lower incidence of residual and recurrent pain likely due to larger lesion sizes.

Can platelet-rich fibrin accelerate neurosensory recovery following sagittal split osteotomy? A double-blind, split-mouth, randomized clinical trial

Neurosensory disturbance (NSD) is common following sagittal split osteotomy (SSO) surgery. The aim of this study was to evaluate the effect of platelet-rich fibrin (PRF) on neurosensory recovery following SSO. This double-blind, split-mouth, randomized clinical trial was performed on patients undergoing bilateral SSO. PRF was applied to one side (selected using computer randomization) after the osteotomy and before fixation. The other side served as the control. The two-point discrimination test and a brush directional stroke test were used to assess NSD at 6 and 12 months postoperative. Self-reported paresthesia was documented using a 10-point visual analogue scale (VAS). Twenty-one patients were included in the study. The results of the two-point discrimination test and the number of subjects who reported a true direction in the brush directional stroke test differed significantly between the treatment and control sides (P=0.001). The recovery of NSD (self-reported paresthesia) was better on the treatment side than on the control side (P=0.001). PRF may enhance the recovery of paresthesia following SSO.

Comparisons of the Computed Tomographic Scan and Panoramic Radiography Before Mandibular Third Molar Extraction Surgery

BACKGROUND Mandibular third molar extraction surgery has a postoperative complication of hypoesthesia of the lower lip and/or chin. The objective of the study was to determine if preoperative radiographic examination by panoramic radiography and computed tomography (CT) scan can predict postoperative complications of mandibular third molar extraction surgery. MATERIAL AND METHODS In total, 479 patients who had mandibular third molar extraction surgery were included in this cross-sectional study. Patients had panoramic radiographies and CT scans to determine the relationship of the tooth, the canal, and the buccolingual position. Inferior alveolar nerve sensory impairment was detected using a two-point discrimination method. Wilcoxon test and Tukey's test were used to compare diagnostic modalities at a 99% confidence level. RESULTS Inferior alveolar nerve was more successfully quantified by CT scan compared to panoramic radiography (p<0.0001, q=8.062). Orthopantomography was better than the CT scan in detecting a close relationship of the tooth and the canal (p<0.0001, q=25.609), but the CT scan was better in detecting the buccolingual position of the teeth (p<0.0001, q=36.757). The age of patients (p<0.0001, q=36.757), postoperative bleeding (p<0.0001, q=15.981), and experience of the surgeon (p<0.0001, q=10.99) had an affected on inferior alveolar nerve sensory impairment. CONCLUSIONS Preoperative panoramic radiography, CT scan, age, the experience of the surgeon, and postoperative bleeding can predict postoperative complications for extraction of a mandibular third molar.

Laser Biophotomodulation in Patients with Neurosensory Disturbance of the Inferior Alveolar Nerve After Sagittal Split Ramus Osteotomy: A 2-Year Follow-Up Study

OBJECTIVE

To evaluate the effect of the application of photobiomodulation in a 2-year follow-up period in patients who have been intervened with a sagittal ramus split osteotomy and present neurosensory disturbance of the inferior alveolar nerve.

BACKGROUND

Photobiomodulation is a common clinical tool in dentistry, for its beneficial effects have been shown in surgical and periodontal wound healing, reducing of swelling and pain, neurosensory recovery, and treatment of temporomandibular joint disorders.

METHODS

This is a 2-year follow-up study with an experimental (Laser) group (n = 33) that received photobiomodulation, and a control (Sham) group (n = 9), placebo. All patients from the Laser group received laser applications (continuous wave of 0.353 W/cm², 27 J in 270 sec per session) on days 1, 2, 3, 5, 10, 14, 21, and 28 after surgery. Neurosensory disturbance was evaluated with five tests: Visual Analog Scale (VAS) for pain and sensitivity, sensitivity threshold test, two-point discrimination, and thermal discrimination. All tests were performed before (24 h before surgery) and after surgery (24 h, 28 days, 60 days, 6 months, 1 year, 2 years, more than 2 years). Participants and evaluator were blinded to intervention. Variables were described with absolute frequencies, percentages, and medians. Ordinal and dichotomous variables were compared with Mann-Whitney's and Fisher's tests, respectively.

RESULTS

Clinical improvement was observed during the follow-up period for the Laser group; general VAS for sensitivity was normal in 11 participants from the Laser group at 2 years postsurgery (40.74%), while no participants from the Sham group achieved this (p = 0.0341). Twenty-three participants recovered initial values for two-point discrimination (69.7%) after 2 years of follow-up (p = 0.0025) as well as sensitivity threshold test. General VAS for pain was normal in 31 patients from the Laser group after 2 years of follow-up (93.94%, p = 0.0254).

CONCLUSIONS

Photobiomodulation was effective for neurosensory recovery on sample studied.

Skin and mucosal ischemia as a complication after inferior alveolar nerve block

The anesthetic block of the inferior alveolar nerve (IAN) is one of the most common techniques used in dental practice. The local complications are due to the failures on the anesthetic block or to anatomic variations in the tap site such as intravascular injection, skin ischemia and ocular problems. The aim of this article is to present a case and discuss the causes of itching and burning sensation, blanching, pain and face ischemia in the oral cavity during the IAN block.

An unusual finding of the auriculotemporal nerve: possible risk factor during preauricular skin incisions

The auriculotemporal nerve (ATN) is a branch of the mandibular nerve and has been implicated for some migraines and its role in Frey's syndrome is well known. An adult cadaver was found to have a duplicated ATN. The anterior trunk ascended as the superficial temporal artery and gave off the branches to the temporomandibular joint, parotid gland, external acoustic meatus and temporal region and communicated with a posterior trunk of the ATN. The posterior trunk ascended via the subcutaneous tissues 1 mm anterior to the auricle and gave off the branches to the anterior auricular region, temporal region and communicated with the anterior trunk. Such a duplicated ATN might be injured with preauricular skin incisions. Knowledge of such an anatomical variation might assist surgeons in iatrogenic injury of the ATN.

The Pull-Through Technique: A Viable Option for Preserving the Inferior Alveolar Nerve during Surgical Resection

The aim of this study was to present a new surgical technique used to remove benign mandibular tumors with minimal damage to the inferior alveolar nerve. The pull-through technique was shown using an ameloblastoma surgical resection as an example. This technique consisted in the reconstruction of the lower jaw associating the resection of the lesion with nerve repair at the same surgical time. The resection was performed using the pull-through technique and the inferior alveolar nerve was preserved. After 6 months, the patient presented a recovery of approximately 80% of sensory function. The surgical technique presented should be considered an important method by which to produce a higher functional outcome to remove benign mandibular tumors with minimal damage to the inferior alveolar nerve and allows the maintenance of quality of life for the patient, as the consequences of this type of surgery are minimized.

High isotropic resolution magnetic resonance imaging of the mandibular canal at 1.5 T: a comparison of gradient and spin echo sequences

OBJECTIVES

The precision of localizing the mandibular canal prior to surgical intervention depends on the achievable resolution, whereas identification of the nerve depends on the image contrast. In our study, we developed new protocols based on gradient and spin echo sequences. The results from both sequences were quantitatively compared for their agreement to identify the most suitable approach.

METHODS

By limiting the field of view to one side of the mandible, three-dimensional acquisitions with T₁ weighted gradient and spin echo sequences were performed with 0.5 × 0.5 × 0.5 mm³ resolution within 6.5 min covering the mandibular canal from the mandibular to the mental foramen. Aliasing artefacts were suppressed by different techniques. A manual segmentation of the mandibular canal from seven healthy volunteers was performed on this section by three different observers. The surface distance of the segmented volumes was computed between both sequences as well as between the different observers as a measure of equality.

RESULTS

The quantitative comparison of the segmentation resulted in an average surface distance of 0.26 ± 0.05 mm between both sequences and an interobserver difference of 0.26 ± 0.08 mm for gradient and 0.29 ± 0.07 mm for spin echo data. By repeated evaluation, a difference of 0.15 ± 0.02 mm for gradient and 0.18 ± 0.03 mm for spin echo data was observed, indicating a slightly higher variability for spin echo images.

CONCLUSIONS

Both sequences can be used to achieve high-resolution images with good contrast and can be used for precise localization of the mandibular canal. Despite a slightly increased difference for the spin echo data, the advantage of an easy and robust setup remains.

Interventions for Dental Implant Placement in Atrophic Edentulous Mandibles: Vertical Bone Augmentation and Alternative Treatments. A Meta-Analysis of Randomized Clinical Trials

BACKGROUND

The purpose of the current study is to assess which vertical bone augmentation techniques are most effective for restoring atrophic posterior areas of the mandible with dental implants and compare these procedures with alternative treatments.

METHODS

Electronic literature searches in PubMed (MEDLINE), Ovid, and the Cochrane Library were conducted to identify all relevant articles published up to July 1, 2015. Eligibility was based on inclusion criteria, and quality assessments were conducted. The primary outcome variables were implant and prosthetic failure. After data extraction, meta-analyses were performed.

RESULTS

Out of 527 potentially eligible papers, 14 randomized clinical trials were included. Out of these 14 studies, four trials assessed short implants (5 to 8 mm) as an alternative to vertical bone augmentation in sites with a residual ridge height of 5 to 8 mm. No statistically significant differences were found in implant (odds ratio [OR]: 1.02; 95% confidence interval [CI]: 0.31 to 3.31; P = 0.98; I²: 0%) or prosthetic failure (OR: 0.64; 95% CI: 0.21 to 1.96; P = 0.43; I²: 0%) after 12 months of loading. However, complications at treated sites increased with the augmentation procedures (OR: 8.33; 95% CI: 3.85 to 20.0; P <0.001; I²: 0%). There was no evidence of any vertical augmentation procedure being of greater benefit than any other for the primary outcomes (implant and prosthetic failure).

CONCLUSIONS

Short implants in the posterior area of the mandible seem to be preferable to vertical augmentation procedures, which present similar implant and prosthetic failure rates but greater morbidity. All the vertical augmentation technique comparisons showed similar intergroup results.

The effect of a platelet-rich fibrin conduit on neurosensory recovery following inferior alveolar nerve lateralization: a preliminary clinical study

This retrospective study aimed to assess the recovery of neurosensory dysfunction following modified inferior alveolar nerve (IAN) lateralization surgery compared to the conventional approach. Data from two groups of patients who underwent IAN lateralization in 2014 were included in this study. In one group, platelet-rich fibrin was placed over the IAN and this was protected with a collagen membrane conduit; the other group underwent the conventional IAN lateralization procedure. Implants were placed immediately. Neurosensory dysfunction was evaluated at 3, 6, and 12 months post-surgery. Demographic, neurosensory disturbance (NSD), subjective two-point discrimination test (TPD), and static light touch test (SLT) data were obtained. Twenty-three IAN lateralization procedures with the placement of 51 implants were performed in 14 patients. At the 6-month follow-up, the number of patients experiencing normal sensation was greater in the modified surgery group, but the 12-month follow-up results were the same in the two groups. More precise sensation was observed with the TPD in the modified group at 6 months, and the modified group demonstrated better SLT scores at 6 months. Although the two groups had comparable results at the 12-month follow-up, it was observed that the modified technique accelerated neural healing within 6 months and reduced the length of the discomfort period.

The inferior alveolar nerve's loop at the mental foramen and its implications for surgery

BACKGROUND

In this study, the authors aimed to identify and measure the anterior extension of the alveolar loop (aAL) and the caudal extension of the alveolar loop (cAL) of the inferior alveolar nerve by using cone-beam computed tomography (CBCT). They also aimed to provide recommendations for surgery in the anterior mandible.

METHODS

In this retrospective case study of the frequency and extension of aAL and cAL, the authors evaluated 1,384 mandibular sites in 694 CBCT scans of dentate and partly edentulous patients, performed mainly for further diagnosis before removal of the mandibular third molars between January 2009 and February 2013, by using multiplanar reconstructions.

RESULTS

The frequency of aAL was 69.73 percent and of cAL was 100 percent. The mean value for aAL was 1.16 millimeters, with a range of 0.3 to 5.6 mm; the mean value for cAL was 4.11 mm, with a range of 0.25 to 8.87 mm. For aAL, 95.81 percent of the sites showed values of 0 to 3 mm; for cAL, 93.78 percent of the sites showed values of 0.25 to 6 mm. Dentate patients showed statistically significantly higher values for cAL than did partly edentulous patients (P = .043). CBCT resolution had a statistically significant impact on cAL measurements (P = .001), with higher values at higher resolution.

CONCLUSIONS

This study showed a high frequency of and large variations in aAL and cAL. In contrast to panoramic radiography, CBCT has been shown to be a reliable tool for identifying and measuring the AL. Therefore, preoperative diagnosis with CBCT is recommended for planning three-dimensional tasks such as implant placement in the vicinity of the mental foramen.

PRACTICAL IMPLICATIONS

Owing to the variability of aAL and cAL measurements, it is difficult to recommend reliable safety margins for surgical procedures such as implant placement, bone harvesting or genioplasty Depending on the indication, the clinician should consider preoperative diagnosis by means of CBCT.

Anatomical variations of mandibular canal detected by panoramic radiography and CT: a systematic review and meta-analysis

OBJECTIVES

To investigate the anatomical variations of the mandibular canal through assessment in situ, panoramic radiography, CT or CBCT and assess their frequency.

METHODS

Articles were selected from databases (Cochrane Library, LILACS, ProQuest, PubMed, Scopus, Web of Science and Google Scholar), articles without limitations of language, in which the main objective was to evaluate the frequency of bifurcation of the mandibular canal through assessment in situ, panoramic radiography, CT or CBCT were selected. A meta-analysis of prevalence using random effects was performed.

RESULTS

Using a selection process in two phases, 15 articles were identified, and a meta-analysis was conducted. The results from these meta-analyses showed that the overall prevalence of anatomical variations for in situ studies was 6.46%, and through assessment of panoramic radiography and CT or CBCT the overall prevalence shown was 4.20% and 16.25%, respectively.

CONCLUSIONS

There are two types of variations of the mandibular canal: the retromolar canal and bifid mandibular canal. The frequency variations through assessing in situ, panoramic radiography and CT or CBCT were 6.46%, 4.20% and 16.25%, respectively.

Intraoperative Measurement of the Distance from the Bottom of Osteotomy to the Mandibular Canal Using a Novel Ultrasonic Device

BACKGROUND

In our previous study, we found that a novel ultrasound (US) device may serve as a useful intraoperative tool to measure the distance from osteotomy to the inferior alveolar canal (IAC).

PURPOSE

To validate our previous results in a larger group of osteotomies in the posterior mandible.

METHODS

During dental implant placement surgery, osteotomies were created using a standardized 2-mm-diameter pilot drill. The distance from the bottom of the osteotome to the IAC was assessed using an ultrasonic device and compared with a standard panoramic radiograph used to measure the same residual distance. The total distance from the crestal bone to the IAC was measured on a preoperative computed tomography (CT) and compared with total US measurements by summing the drill depth with residual depth measurements.

RESULTS

Mean radiographic and US residual distances were 5.19 ± 1.95 mm, 5.01 ± 1.82 mm, p = 0.79 respectively. These measurements presented strong positive correlations (r = 0.61, p = .01). Mean total CT distance was 13.48 ± 2.66 mm; mean total US calculation was 13.69 ± 2.51 mm. No significant difference was found (p > .05).

CONCLUSIONS

The results support our previous pilot study and confirm that the tested US device identifies the IAC and measures the distance from the osteotomy to the roof of the mandibular canal.

Cortical Bone Augmentation Versus Nerve Lateralization for Treatment of Atrophic Posterior Mandible: A Retrospective Study and Review of Literature

PURPOSE

We sought to assess implant success/survival/failure rate following cortical autogenous tenting technique (CATT) versus inferior alveolar nerve transposition (IANT) in the posterior mandible.

MATERIALS AND METHODS

Patients who underwent these two procedures between 2007 and 2011 were analyzed. CATT was performed using lateral ramus block graft and implants were inserted simultaneously or after 4 to 6 months. In IANT, implants were placed simultaneously after nerve transposition with or without mental foramen involvement. Data regarding marginal bone level (MBL), pus discharge (PD), neurosensory dysfunction (NSD), implant mobility, and failure were collected. Success rate was measured based on Pisa Consensus. Independent sample t-test with a significance level of 0.05 was used to compare implant dimensions and MBL changes between the two techniques.

RESULTS

A total of 118 patients with a mean age of 54.85 years were included. The mean follow-up after CATT and IANT was 37.97 and 18.51 months, respectively. The overall survival and success rates of dental implants in the CATT group were 98.73% and 71.52%, respectively. The corresponding values for IANT subjects were 98.74% and 94.56%, respectively. Implant length and diameter in IANT group were significantly longer and wider than implants used after CATT (p value < .001). MBL changes in both techniques were less than 1 mm (p value = .79). Two cases of NSD, seven PD, and two implant failures were found in the CATT group. For IANT patients, seven permanent NSD, two PD, two implant failures, and one mandibular fracture were documented.

CONCLUSION

Both techniques had implant survival rates similar to implants placed in unaltered bone. A higher implant success rate, albeit with higher incidence of long-lasting nerve damage, was observed in the IANT group.

Inferior Alveolar Nerve Lateralization and Transposition for Dental Implant Placement. Part II: a Systematic Review of Neurosensory Complications

Objectives

This article, the second in a two-part series, continues the discussion of inferior alveolar nerve lateralization/transposition for dental implant placement. The aim of this article is to review the scientific literature and clinical reports in order to analyse the neurosensory complications, risks and disadvantages of lateralization/transposition of the inferior alveolar nerve followed by implant placement in an edentulous atrophic posterior mandible.

Material and Methods

A comprehensive review of the current literature was conducted according to the PRISMA guidelines by accessing the NCBI PubMed and PMC databases, as well as academic sites and books. The articles were searched from January 1997 to July 2014. Articles in English language, which included adult patients between 18 - 80 years of age who had minimal residual bone above the mandibular canal and had undergone inferior alveolar nerve (IAN) repositioning, with minimum 6 months of follow-up, were included.

Results

A total of 21 studies were included in this review. Ten were related to IAN transposition, 7 to IAN lateralization and 4 to both transposition and lateralization. The IAN neurosensory disturbance function was present in most patients (99.47% [376/378]) for 1 to 6 months. In total, 0.53% (2/378) of procedures the disturbances were permanent.

Conclusions

Inferior alveolar nerve repositioning is related to initial transient change in sensation in the majority of cases. The most popular causes of nerve damage are spatula-caused traction in the mucoperiosteal flap, pressure due to severe inflammation or retention of fluid around the nerve and subsequent development of transient ischemia, and mandibular body fracture.

Inferior alveolar nerve lateralization and transposition for dental implant placement. Part I: a systematic review of surgical techniques

Objectives

The purpose of this first part of a two-part series was to review the literature concerning the indications, contraindications, advantages, disadvantages and surgical techniques of the lateralization and transposition of the inferior alveolar nerve, followed by the placement of an implant in an edentulous atrophic posterior mandible.

Material and Methods

A comprehensive review of the current literature was conducted according to the PRISMA guidelines by accessing the NCBI PubMed and PMC database, academic sites and books. The articles were searched from January 1997 to July 2014 and comprised English-language articles that included adult patients between 18 and 80 years old with minimal residual bone above the mandibular canal who had undergone inferior alveolar nerve (IAN) repositioning with a minimum 6 months of follow-up.

Results

A total of 16 studies were included in this review. Nine were related to IAN transposition, 4 to IAN lateralization and 3 to both transposition and lateralization. Implant treatment results and complications were presented.

Conclusions

Inferior alveolar nerve lateralization and transposition in combination with the installation of dental implants is sometimes the only possible procedure to help patients to obtain a fixed prosthesis, in edentulous atrophic posterior mandibles. With careful pre-operative surgical and prosthetic planning, imaging, and extremely precise surgical technique, this procedure can be successfully used for implant placement in edentulous posterior mandibular segments.

Inferior alveolar nerve injuries following implant placement - importance of early diagnosis and treatment: a systematic review

OBJECTIVES

The purpose of this article is to systematically review diagnostic procedures and risk factors associated with inferior alveolar nerve injury following implant placement, to identify the time interval between inferior alveolar nerve injury and its diagnosis after surgical dental implant placement and compare between outcomes of early and delayed diagnosis and treatment given based on case series recorded throughout a period of 10 years.

MATERIAL AND METHODS

We performed literature investigation through MEDLINE (PubMed) electronic database and manual search through dental journals to find articles concerning inferior alveolar nerve injury following implant placement. The search was restricted to English language articles published during the last 10 years, from December 2004 to March 2014.

RESULTS

In total, we found 33 articles related to the topic, of which 27 were excluded due to incompatibility with established inclusion criteria. Six articles were eventually chosen to be suitable. The studies presented diagnostic methods of inferior alveolar nerve sensory deficit, and we carried out an assessment of the proportion of patients diagnosed within different time intervals from the time the injury occurred.

CONCLUSIONS

Various diagnostic methods have been developed throughout the years for dealing with 1 quite frequent complication in the implantology field - inferior alveolar nerve injury. Concurrently, the importance of early diagnosis and treatment was proved repeatedly. According to the results of the data analysis, a relatively high percentage of the practitioners successfully accomplished this target and achieved good treatment outcomes.

Bupivacaine mandibular nerve block affects intraoperative blood pressure and heart rate in a Yucatan miniature swine mandibular condylectomy model: a pilot study

PURPOSE/AIM

The primary objective was to evaluate the effect of a bupivacaine mandibular nerve block on intraoperative blood pressure (BP) and heart rate (HR) in response to surgical stimulation and the need for systemic analgesics postoperatively. We hypothesized that a mandibular nerve block would decrease the need for systemic analgesics both intraoperatively and postoperatively.

MATERIALS AND METHODS

Fourteen adult male Yucatan pigs were purchased. Pigs were chemically restrained with ketamine, midazolam, and dexmedetomidine and anesthesia was maintained with isoflurane inhalant anesthesia. Pigs were randomized to receive a mandibular block with either bupivacaine (bupivacaine group) or saline (control group). A nerve stimulator was used for administration of the block with observation of masseter muscle twitch to indicate the injection site. Invasive BP and HR were measured with the aid of an arterial catheter in eight pigs. A rescue analgesic protocol consisting of fentanyl and lidocaine was administered if HR or BP values increased 20% from baseline. Postoperative pain was quantified with a customized ethogram. HR and BP were evaluated at base line, pre-rescue, 10 and 20 min post-rescue.

RESULTS

Pre-rescue mean BP was significantly increased (p = .001) for the bupivacaine group. Mean intraoperative HR was significantly lower (p = .044) in the bupivacaine versus saline group. All other parameters were not significant.

CONCLUSION

Addition of a mandibular nerve block to the anesthetic regimen in the miniature pig condylectomy model may improve variations in intraoperative BP and HR. This study establishes the foundation for future studies with larger animal numbers to confirm these preliminary findings.

Anomalous Bilateral Communication between the Inferior Alveolar Nerve and the Auriculotemporal Nerve: A Rare Variation

Branches of the posterior division of the mandibular nerve show various anomalous communications in the infratemporal region. Understanding such communication has relevance in the management of neuropathies and surgical procedures in this region. This study was conducted to explore such communicating branches, anticipating that they might provide information of clinical significance. A total of 15 human cadavers (30 infratemporal regions) were studied to explore such communicating branches in infratemporal region. The branches of the posterior division of the mandibular nerve were carefully dissected, and these branches were studied and analysed for any abnormal course. In one case, a rare type of bilateral communication between the auriculotemporal nerve and the inferior alveolar nerve, forming a loop with no association with any structure, was observed. It is possible that such communicating branches may be associated with delayed regression of the first arch vessels. The clinical implications of these anomalous communications require further detailed study for improved management of neuropathies and surgical procedures.

Anatomical variation of mandibular canal simulating a recurrence of odontogenic tumor

Mandibular nerve has an important role in the field of oral maxillofacial surgery. Furthermore, several anatomical variations can be found and are clinically relevant mainly in procedures involving the posterior mandible. The unknown of these anatomical variations of the inferior alveolar nerve have been implicated with complications in the performance of surgical procedures and anesthesia in dental and maxillofacial practice. The present paper reports a rare anatomical variation of inferior alveolar nerve mimicking a recurrence of keratocystic odontogenic tumor.

Microanatomy and surgical approaches to the infratemporal fossa: an anaglyphic three-dimensional stereoscopic printing study

OBJECTIVE

The infratemporal fossa (ITF) is a continuation of the temporal fossa between the internal surface of the zygoma and the external surface of the temporal bone and greater wing of the sphenoid bone that is sitting deep to the ramus of the mandible. The principal structure to understanding its relationships is the lateral pterygoid muscle. Other important structures are the medial pterygoid muscle, the maxillary artery, the pterygoid venous plexus, the otic ganglion, the chorda tympani nerve and the mandibular nerve. In this study, we describe the microsurgical anatomy of the ITF, as viewed by step-by-step anatomical dissection and also through the perspective of three lateral approaches and one anterior surgical approach.

METHODS

Eight cadaver specimens were dissected. In one side of all specimens, an anatomical dissection was done in which a wide preauricular incision from the neck on the anterior border of the sternoclidomastoid muscle at the level of the cricoid cartilage to the superior temporal line was made. The flap was displaced anteriorly and the structures of the neck were dissected followed by a zygomatic osteotomy and dissection of the ITF structures. On the other side were the surgical approaches to the ITF. The combined infratemporal and posterior fossa approach was done in two specimens, the subtemporal preauricular infratemporal fossa approach in two, the zygomatic approach in two, and the lateral transantral maxillotomy in two. The anatomical dissections were documented on the three-dimensional (3D) anaglyphic method to produce stereoscopic prints.

RESULTS

The lateral pterygoid muscle is one of the principal structures to enable understanding of the relationships into the ITF. The tendon of the temporal muscle inserts in the coronoid process at the ITF. The maxillary artery is the terminal branch of the external carotid artery that originates at the neck of the mandible and runs into the parotid gland. In our dissections the maxillary artery was lateral to the buccal, lingual, and inferior alveolar nerves. We found the second part of the maxillary artery superficial to the lateral pterygoid muscle in all specimens The anterior and posterior branches of the deep temporal artery supply the temporal muscle. In two cases we found a middle deep temporal artery. The different approaches that we used provided different views of the same anatomical landmarks and this provides not only safer surgery but also the best choice to approach the ITF according with the pathology extension.

CONCLUSIONS

The ITF is a complex region on the skull base that is affected by benign and malignant tumors. The study through different routes is helpful to disclose the relationship among the anatomical structures. Although the authors have shown four approaches, there are a variety of approaches and even a combination of these can be used. This type of anatomical knowledge is essential to choosing the best approach to treat lesions in this area.

Injury of the Inferior Alveolar Nerve during Implant Placement: a Literature Review

Objectives

The purpose of present article was to review aetiological factors, mechanism, clinical symptoms, and diagnostic methods as well as to create treatment guidelines for the management of inferior alveolar nerve injury during dental implant placement.

Material and Methods

Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were inferior alveolar nerve injury, inferior alveolar nerve injuries, inferior alveolar nerve injury implant, inferior alveolar nerve damage, inferior alveolar nerve paresthesia and inferior alveolar nerve repair. The search was restricted to English language articles, published from 1972 to November 2010. Additionally, a manual search in the major anatomy, dental implant, periodontal and oral surgery journals and books were performed. The publications there selected by including clinical, human anatomy and physiology studies.

Results

In total 136 literature sources were obtained and reviewed. Aetiological factors of inferior alveolar nerve injury, risk factors, mechanism, clinical sensory nerve examination methods, clinical symptoms and treatment were discussed. Guidelines were created to illustrate the methods used to prevent and manage inferior alveolar nerve injury before or after dental implant placement.

Conclusions

The damage of inferior alveolar nerve during the dental implant placement can be a serious complication. Clinician should recognise and exclude aetiological factors leading to nerve injury. Proper presurgery planning, timely diagnosis and treatment are the key to avoid nerve sensory disturbances management.

Positional relationships between the masticatory muscles and their innervating nerves with special reference to the lateral pterygoid and the midmedial and discotemporal muscle bundles of temporalis

For an accurate assessment of jaw movement, it is crucial to understand the comprehensive formation of the masticatory muscles with special reference to the relationship to the disc of the temporomandibular joint. Detailed dissection was performed on 26 head halves of 14 Japanese cadavers in order to obtain precise anatomical information of the positional relationships between the masticatory muscles and the branches of the mandibular nerve. After complete removal of the bony elements, the midmedial muscle bundle in all specimens and the discotemporal muscle bundle in 6 specimens, derivatives of the temporalis, which insert into the disc were observed. On the anterior area of the articular capsule and the disc of the temporomandibular joint, the upper head of the lateral pterygoid, the midmedial muscle bundle of temporalis and the discotemporal bundle of temporalis were attached mediolaterally, and in 3 specimens the posterosuperior margin of the zygomaticomandibularis was attached to the anterolateral area of the disc. It is suggested that these muscles and muscle bundles contribute to various mandibular movements. Although various patterns of the positional relationships between the muscles and muscle bundles and the their innervating nerves are observed in the present study, relative positional relationships of the muscles and muscle bundles and of nerves of the mandibular nerve are consistent. A possible scheme of the developmental formation of the masticatory muscles based on the findings of the positional relationships between the muscles and the nerves is presented.

Hand/face border as a limiting boundary in the body representation in monkey somatosensory cortex

Horizontal intracortical connections may form one substrate for representational plasticity in somatosensory cortex. Electrophysiological mapping demonstrated the finer details of the representations of the hand, lower jaw, neck, and face in area 3b of normal macaque monkeys. Injections of two fluorescent tracers then defined the extent to which horizontal connections crossed from the face into the hand representations and vice versa in area 3b. Connections are widely distributed within cortical representations of skin areas innervated by cervical nerves or by the trigeminal nerve but do not cross a border defined by the anterior limit of the representation of skin innervated by the second cervical nerve. This border separates the representation of the muzzle, innervated only by the mandibular nerve, and the representation of the lower jaw and neck region, innervated by the second and third cervical nerves but overlapped by the mandibular nerve. Thus, the muzzle representation lacks connections with the hand and with the lower jaw and neck representations, but the representations of the hand and of the lower jaw and neck are strongly interconnected. Overlap of the hand and of the lower jaw and neck representations and of their horizontal intracortical connections may form one basis for expansions of the lower jaw representation into that of the hand when peripheral input from the hand is lost. Lack of connections with the rest of the face representation may limit this spread.