A review of the mandibular and maxillary nerve supplies and their clinical relevance

[Strategies for prevention and treatment of vascular and nerve injuries in mandibular anterior implant surgery]

Important anatomical structures such as mandibular incisive canal, tongue foramen, and mouth floor vessels may be damaged during implant surgery in the mandibular anterior region, which may lead to mouth floor hematoma, asphyxia, pain, paresthesia and other symptoms. In severe cases, this can be life-threatening. The insufficient alveolar bone space and the anatomical variation of blood vessels and nerves in the mandibular anterior region increase the risk of blood vessel and nerve injury during implant surgery. In case of vascular injury, airway control and hemostasis should be performed, and in case of nerve injury, implant removal and early medical treatment should be performed. To avoid vascular and nerve injury during implant surgery in the mandibular anterior region, it is necessary to be familiar with the anatomical structure, take cone-beam computed tomography, design properly before surgery, and use digital technology during surgery to achieve accurate implant placement. This article summarizes the anatomical structure of the mandibular anterior region, discusses the prevention strategies of vascular and nerve injuries in this region, and discusses the treatment methods after the occurrence of vascular and nerve injuries, to provide clinical reference.

Template based segmental mandibulectomy with nerve preservation and patient-specific PEEK plate reconstruction in a dog

A 7-year-old French Bulldog presented with an acanthomatous ameloblastoma affecting approximately 30% of the right mandibular body. We utilized a patient-specific 3D-printed surgical template to perform lateral fenestration of the mandible and elevation of the inferior alveolar nerve (IAN), facilitating nerve preservation during subsequent segmental mandibulectomy. The resulting critical-sized bone defect was anatomically stabilized using a patient-specific polyetheretherketone (PEEK) bridging plate. The recovery process was uneventful, with maintained occlusion and orofacial sensitivity.Similar to cases in humans with ameloblastoma, preserving orofacial sensitivity through the preservation of the inferior alveolar nerve seems feasible in dogs. Consequently, potential negative consequences of permanent regional denervation, which are unavoidable in traditional mandibulectomy, can be avoided. Bridging the ostectomy with a PEEK plate, offering advantages such as radiolucency, absence of imaging artifacts, and a modulus of elasticity similar to bone, proved to be functional in this canine patient, with no signs of complications observed up to the latest follow-up at 6 months.

Ectopic Dental Canal: A Case Report Highlighting a Unique Bifid Mandibular Canal Variant

Bifid mandibular canals are common anatomical findings with variations based on direction and location of branching, which carry significant clinical implications for endodontic and surgical dental procedures. This case report describes a previously unreported ectopic dental canal that branches off the superior border of the mandibular canal, enters the apex of a mandibular second molar, traverses through the root, anastomoses with the root canal system, and subsequently exits through the lingual aspect of the root. The anastomosis of this ectopic dental canal with the mesial lingual canal led to significant bleeding during rotary instrumentation. This unique anatomical variation demonstrates the importance of a thorough cone-beam computed tomography analysis to identify critical structures prior to undertaking dental procedures involving the root apices of mandibular posterior teeth and adjacent areas.

Neurological Complications following Surgical Treatments of the Lower Molars

Aim

The current review aims to explore postoperative neurological complications in third molar extractive surgery.

Materials and Methods

The PRISMA protocols were followed when conducting this review. We found a total of 2,250 articles that matched our topic using the Boolean keywords, mandibular nerve complications AND oral surgery, from PubMed (1,083), Scopus (435), and Web of Science (732), with the filters of English language articles, time range January 1, 2003, to September 30, 2023, and human studies. After 762 duplicates were eliminated, there remained 1,488 articles. Eleven final articles were deemed of the highest relevance to our topic by eliminating articles in animals, non-English language, reviews, meta-analysis, and off-topic. A potential risk in the third molar extraction was temporary loss of sensibility often caused by mild compression or irritation of the mandibular nerve. This typically resolves within weeks or months, but in severe cases, recovery might take longer. Permanent loss of sensation can occur, indicating significant nerve damage and lasting effects on touch, temperature, or pain perception.

Conclusions

Various treatments exist for nerve damage, including low-level laser therapy, pain management medications, or physical therapy. While these therapies may improve neurosensory impairment, patients often report a decline in their quality of life.

Lacrimal Neuralgia: A Case Report and Comprehensive Review of the Literature

PURPOSE OF REVIEW

Lacrimal neuralgia is a rare periorbital neuralgia. To date, only nine cases have been reported in the literature. Herein, we report a case and a comprehensive overview of the entity with a focus on the differential diagnosis of lacrimal neuralgia. Additionally, we propose putative diagnostic criteria for this rare neuralgia based on cases that have been reported.

RECENT FINDINGS

Among the ten cases of lacrimal neuralgia reported (including the one in this review), seven out of ten were idiopathic, and the other three were considered secondary. Most patients reported stabbing and shooting pain that was either paroxysmal or continuous. The most effective therapy was nerve block for seven patients and pregabalin for three patients. The most important clues to differentiate lacrimal neuralgia from other causes of periorbital pain include pain topography and pain with features suggestive of neuralgia. The core feature of lacrimal neuralgia is neuralgic pain located in the area supplied by the lacrimal nerve, and the etiology could be primary or secondary. Responsiveness to anesthetic blockade might better serve as a confirmational, rather than mandatory, criterion for diagnosis.

Evaluation of the morphology of accessory canals of the canalis sinuosus via cone-beam computed tomography

PURPOSE

This study aims to assess the presence of accessory canal (AC) associated with canalis sinuous (CS), describing their frequency, lateralization, location, direction, and measurements in cone beam computed tomography (CBCT).

METHODS

Axial, coronal, sagittal, and cross-sectional reconstructions were analyzed in 248 CBCT images and the presence of CS, the presence of AC associated with CS, the lateralization, localization, and direction course of AC associated with CS was evaluated. CS diameter, AC diameter, the distance between the nasal cavity floor and CS (M1), CS and the buccal cortical bone (M2), and CS and the alveolar ridge (M3) were measured.

RESULTS

CS was detected in all CBCT scans as bilaterally. The prevalence of AC associated with CS was 35.5%. There was a significant difference between dental status anthe d presence of AC associated with CS. There was a significant difference between gender, dental status, and lateralization of AC associated with CS. While M1 was greater in male patients than females, M3 was greater in female patients. M2 and M3 were greater in younger patients.

CONCLUSION

Clinicians performing surgical procedures should keep in mind that anatomical variations of the vascular nerve bundle may be seen. M1, M2, and M3 measurements can be affected by gender, age, and dental status.

Bifid Mandibular Canal: A Proportional Meta-Analysis of Computed Tomography Studies

Introduction

Growing body of evidences showed different grades in prevalence of bifid mandibular canals. Because the previous reviews focused solely on patient-level occurrence, hemi-mandible-level prevalence, bilateral symmetry, length, and diameter of bifid mandibular canals were required to be estimated collectively. The research question of this meta-analysis was "What is the prevalence of bifid mandibular canal among patients seeking computed tomography examinations"?

Materials and Methods

In vivo, computed tomography, and cross-sectional studies were eligible. Studies, with less than 100 subjects or anatomic site restriction or controlled class of bifid mandibular canal, were excluded. Joanna Briggs Institute (JBI) critical appraisal tool for prevalence studies was used to assess methodological quality of all included studies. Random effect meta-analyses for proportion of bifid mandibular canal were done.

Results

40 studies met the inclusion criteria. All studies were selected for both systematic review and meta-analyses. Totally, 17714 patients and 31973 hemi-mandibles were included. All eligible studies showed moderate risk of bias on average. Resulting from the random effect model, more than 20% of patients seeking computed tomographic examinations had bifid mandibular canals (BMCs) which penetrated into slightly more than 14% of hemi-mandibles. Of the patients having bifid mandibular canals (BMCs), nearly 23% exhibited such anatomy on both sides of their mandibles. Estimated mean length and diameter of the accessory canals of bifid mandibular canals were 12.17 mm and 1.54 mm, respectively.

Conclusion

The geographical locations, classifications, reliability test, and voxel size of computed tomography were all implicated in the prevalence of bifid mandibular canals along with gender and laterality, although considerable heterogeneity and bias were detected.

Variation of Mandibular Canal Branching Related to Anatomical Regions in Mandible: A Radiographic Study Without Contrast

PURPOSE

Screening mandibular canal branches and awareness of these possible canal branches is vital for patient safety and surgical success. The aim of this study was to evaluate the prevalence and localization of mandibular canal branching (MCB).

METHODS

This is an institutional and retrospective cohort study of patients who presented for evaluation of cone beam computed tomography (CBCT) between 2019 and 2020. The prevalence of MCB and the related foramina was estimated according to anatomical regions. Predictor variables were gender, age, anatomical region, and side of branches. Outcome variable of the study was MCB. Thus, multiple correspondence analysis was performed to determine the relationships between the categories of the variables, as well as between variables.

RESULTS

CBCT images were obtained from 180 patients (n = 360 hemimandible; 90 males, 90 females). MCB was observed in 130 (72.2%) of 180 patients (mean age = 38.2 ± 11.8 years). MCB was observed in 63 (48.5%) males and 67 (51.5%) females, and the prevalence of MCB did not differ significantly according to gender (P = .618). MCB was mostly observed in the molar region (69 branches, 34.3%). Foramina were detected in 60 of 248 branches (24.19%) and were mostly observed in the retromolar region (28 foramina, 46.7%). "Quadrafid" branching was detected in 2 females (1.11%). Female patients aged 19-38 years were more prone to have MCB in molar and retromolar regions. MCB was more likely to occur bilaterally. There was also a high positive correlation among the MCB, side, and anatomical regions.

CONCLUSIONS

MCB is not a rare anatomical variation, and even quadrafid branching can be observed in the hemimandible. CBCT images should be examined carefully for possible MCB to minimize postoperative complications during dental surgery.

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.

Detection Rate and Variability in Measurement of Mandibular Incisive Canal on Cone-Beam Computed Tomography: A Study of 220 Dentate Hemi-Mandibles from Italy

The mandibular incisive canal (MIC) is a small bony channel located in the interforaminal region; it represents the anterior continuation of the mandibular canal. Cone-beam computed tomography (CBCT) is the most commonly utilized radiological technique for assessing the MIC. The main purpose of this study was to evaluate the detectability and variability in measurements of the MIC on CBCT. A total of 220 dentate hemi-mandibles were retrospectively selected for this study. For each hemi-mandible, the detectability, diameter, and distance of the MIC from anatomical landmarks (cortical plates and tooth apices) were evaluated in consensus by two observers. The analysis was performed at four different levels (first premolar, canine, lateral incisor, and central incisor) and was repeated after one month. The variability of MIC measurements was expressed as the coefficient of repeatability (CR), obtained from the Bland-Altman analysis. The MIC detection rate reduced from the first premolar to the central incisor (from 82.3% to 0.5%). The CR of MIC measurements (diameter and distances from anatomical landmarks) was ≤0.74 mm. Although the MIC is difficult to detect in a non-negligible percentage of cases, the limited variability in measurements confirms that CBCT is an effective technique for the assessment of the MIC.

Biology and Endodontics: Thinking Outside the Box

Combining evidence-based dentistry (EBD) with years of clinician experience should have a great impact on treatment planning and decision-making for achieving the best treatment outcomes, thus warranting patient satisfaction. In addition, understanding and appreciating the role of biology on the reliance on and progress of treatment healing is also a crucial element that clinicians should always keep in mind in their dental practice. This study demonstrates that clinicians should always rely on their own clinical and radiographical test results for evaluation and judgment of any clinical situation before presenting and proceeding with any dental treatment for their patients.

Effect of Photobiomodulation Therapy with 915 nm Diode Laser on Pain Perception During Local Anesthesia of Maxillary Incisors: A Randomized Controlled Trial

This study aimed to evaluate the effect of photobiomodulation therapy (PBMT) with 915 nm wavelength on pain reduction during maxillary incisors' local infiltration in a randomized clinical trial study. A prospective triple-blinded split mouth clinical trial was designed to assess pain perception during needle insertion and local anesthetic injection in 32 healthy patients required operative caries management on contralateral maxillary incisors. After laser treatment (915nm, power of1.5 W, duty cycle of 60% and energy density of 72 J/cm² ) in active group and no irradiation in sham group, the injection was performed. Patients' perception of pain was immediately assessed using numerical rating scale (NRS) for pain. Washout period between two appointments was one week. Wilcoxon signed rank and Pearson correlation statistical analysis were used to assess for comparison of pain score between two appointments and the effect of anxiety level of previous dental injections. The mean scores of pain for the active laser and sham laser groups were 2.5±2.19 and 4.34± 2.52, respectively with a statistically significant higher NRS in the sham laser group (P˂0.05). In this study's condition, diode PBMT reduced pain during infiltration on maxillary incisors. Anxiety experience of dental injection had no significant effect on pain perception scale (P˃0.05).

Comprehensive review of the incisive branch of the inferior alveolar nerve

The incisive branch of the inferior alveolar nerve is a vital anatomical structure within the anterior mandible that has not been thoroughly defined and outlined in reports in the literature until recent years. Advances in radiological imaging, particularly the widespread use of cone-beam computed tomography has allowed for accurate visualization of the mandibular incisive canal (MIC) and its associated incisive branch of the inferior alveolar nerve. Surgical damage to the MIC, which could result in hemorrhage and sensory disturbance, may occur in commonly practiced oral and maxillofacial procedures, such as chin bone harvesting, implant placement, fracture repair and removal of pathologic entities of the anterior mandible. Knowledge of both the presence, dimensions and location of the incisive branch is a vital component to pre and peri-operative planning of oral and maxillofacial surgeries performed within the mandible, particularly within the interforaminal zone. In this article, the terminology, anatomy, imaging, surgical consideration, and pathology of the incisive branch will be discussed.

Recovery of Sensation Over the Distribution of the Inferior Alveolar Nerve Following Mandibular Resection Without Nerve Reconstruction

PURPOSE

To assess the long-term recovery of sensation in the lower lip after mandibular resection without reconstruction of the inferior alveolar nerve.

MATERIAL AND METHODS

Thirty patients who had mandibular resection carried out without reconstruction of the inferior alveolar nerve were examined after an interval ranging from 6 to 33 years.

RESULTS

Only 1 patient, seen 10 years after resection, was totally numb over the distribution of the inferior alveolar nerve. The other 29 patients had some return of sensation and many had a significant return, though it may take several years to reach the final result. Utilizing the MRC scale 70% of patients achieved S3 (return of superficial cutaneous pain and tactile sensibility without over response) CONCLUSION: This study can serve as a baseline for comparison with patients who have had mandibular resection with reconstruction of the inferior alveolar nerve to assess if this procedure improves the outcomes.

Evaluation of Location of Canalis Sinuosus in the Maxilla Using Cone Beam Computed Tomography

Background/Aim: The aim of this study is to evaluate the prevalence of a canalis sinuosus (CS) in the anterior maxilla.

Material and Methods: CBCT images of 673 patients (322 females and 351 males) were examined retrospectively with regard to age, gender, location of CS and relation to impacted canines. The age of the patients ranged from 14 to 82 years; the mean age of the female patients was 43.54 years and that of the males was 45.75 years. IBM SPSS 22 for Windows was used for statistical analysis of the results. Statistical comparisons between two categorical variables were conducted using chi-square tests. Significance was set at (p< 0.05).

Results: It was observed that 8.17% of the patients in this study exhibited accessory canals (AC) of CS (n= 55). There was no significant difference in CS prevalence between ages, age groups, and location in our study (p> 0.5). There was significant difference in CS prevalence between the genders (p< 0.5).

Conclusions: It is important to take into consideration the presence of AC of the CS during surgical procedures in the anterior maxilla. It was also found that CBCT is more helpful than other techniques in detecting accessory canals in the region of interest.

Invasion of the canalis sinuosus by dental implants: A report of 3 cases

The canalis sinuosus (CS) and its accessory canals (ACs) are anatomical structures in the anterior maxilla. These structures are often neglected when planning implant surgery because their clinical significance is still not well-defined. After a retrospective evaluation of 194 patients rehabilitated with dental implants in the anterior maxilla, 3 patients were identified who presented unexpected chronic neurosensory disturbances without any clinical signs supportive of implant failure. Tomographic assessment using cone-beam computed tomography (CBCT) revealed the invasion of the CS and ACs by dental implants, which appeared to explain the patients' symptoms. The purpose of this report was to familiarize practicing dentists and specialists with the CS and its ACs. Unanticipated neurosensory symptoms after implant placement in the anterior maxilla justify the use of CBCT to rule out an injury to this neurovascular bundle.

Neurotrophic effects of dental pulp stem cells on trigeminal neuronal cells

Evidence indicates that dental pulp stem cells (DPSC) secrete neurotrophic factors which play an important role in neurogenesis, neural maintenance and repair. In this study we investigated the trophic potential of DPSC-derived conditioned medium (CM) to protect and regenerate isolated primary trigeminal ganglion neuronal cells (TGNC). DPSC and TGNC were harvested by enzymatic digestion from Wister-Hann rats. CM was collected from 72 h serum-free DPSC cultures and neurotrophic factors; nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and glial cell line-derived neurotrophic factor (GDNF) were analysed by specific enzyme-linked immunosorbent assays (ELISAs). Primary co-cultures of DPSC and TGNC were established to evaluate the paracrine effects of DPSC. In comparison, NGF was used to evaluate its neurotrophic and neuritogenic effect on TGNC. Immunocytochemistry was performed to detect the neuronal-markers; neuronal nuclei (NeuN), microtubule-associated protein-2 (MAP-2) and βIII-tubulin. Quantitative real time polymerase chain reaction (qRT-PCR) was used to analyse neuronal-associated gene expression of NeuN, MAP-2, βIII-tubulin in addition to growth-associated protein-43 (GAP-43), Synapsin-I and thermo-sensitive transient receptor potential vanilloid channel-1 (TRPV1). DPSC-CM contained significant levels of NGF, BDNF, NT-3 and GDNF. DPSC and DPSC-CM significantly enhanced TGNC survival with extensive neurite outgrowth and branching as evaluated by immunocytochemistry of neuronal markers. DPSC-CM was more effective in stimulating TGNC survival than co-cultures or NGF treated culture. In comparison to controls, DPSC-CM significantly upregulated gene expression of several neuronal markers as well as TRPV1. This study demonstrated that DPSC-derived factors promoted survival and regeneration of isolated TGNC and may be considered as cell-free therapy for TG nerve repair.

Cone beam computed tomography analysis of accessory canals of the canalis sinuosus: A prevalent but often overlooked anatomical variation in the anterior maxilla

STATEMENT OF PROBLEM

Accessory canals of the canalis sinuosus, a bony canal carrying the anterior superior alveolar nerve and vessels, can often be present but overlooked in the anterior maxilla. Dental implant placement in this area may damage neurovascular branches if this anatomic variation is not carefully identified, resulting in unexpected complications.

PURPOSE

The purpose of this retrospective study was to identify accessory canals of the canalis sinuosus and analyze their relationship to the terminal canalis sinuosus and anterior maxilla in Chinese patients to provide a warning for surgeons operating in the anterior maxilla.

MATERIAL AND METHODS

Cone beam computed tomography (CBCT) scans of 1007 Chinese patients were examined to identify the prevalence and size of accessory canals with at least 1.0-mm diameter. Axial position of this canal was classified referring to the nasal cavity and adjacent teeth. Its sagittal position was determined by the distance from the bifurcation site of canalis sinuosus to the buccal alveolar crest and the distance from the canal opening to the palatal alveolar crest. Diameter of the terminal canalis sinuosus, distance from the terminal canalis sinuosus to the buccal alveolar crest, and anterior maxillary volume were measured on all scans. Binary logistic regression and the Spearman rank correlation coefficient were used for prevalence and diameter analysis.

RESULTS

The prevalence of the accessory canal was 36.9%, positively correlated the anterior maxillary volume (OR 1.408) and negatively correlated with the distance from the terminal canalis sinuosus to the buccal alveolar crest (OR 0.921). Average diameter of such canal was 1.1 ±0.1 mm, significantly higher in men, positively correlated with the diameter of terminal canalis sinuosus (r_s=0.163) and the distance from the canal opening to the palatal alveolar crest (r_s=0.192). All accessory canals started below the buccal cortical bone, 19.3 ±2.7 mm away from the buccal alveolar crest. There were 61.9% accessory canals opened between the central and the lateral incisors. Openings here and in the central incisor region were closer to the alveolar crest than that between the lateral incisor and the canine (P<.05).

CONCLUSIONS

Accessory canals of the canalis sinuosus have high prevalence in the anterior maxilla in a Chinese population. Large anterior maxillary volume has been demonstrated as a risk factor associated with the presence of such canals. The region between the central and the lateral incisors was a predominant location. Openings in this region were closer to the alveolar crest than those between the lateral incisor and the canine.

The mandibular incisive foramen, a false mental foramen

BACKGROUND

The mandibular incisive foramen (MIF) is an opening on the external surface of the dentate mandibular body, medial to, and facing the mental foramen (MF). There is actually scarce evidence of such MIF.

CLINICAL PRESENTATION

A retrospective Cone Beam CT (CBCT) study of the archived files of a 56 y.o. male patient was documented anatomically for dental medical purposes. In the 2^nd premolar region of the left hemimandible were found two adjacent foramina facing one each other: the distal one was opened medially, while the medial one was oriented distally. On axial CBCT slices the mandibular canal was detected to open at the distal foramen in the outer cortical plate of the mandible. The medial foramen in that cortical plate served as entrance to the mandibular incisive canal, thus being a MIF.

CONCLUSION

CBCT accurately distinguishes the canals opening on the outer cortical plate of the mandible thus is of use to differentiate a MIF from a MF. Such adjacent foramina expose at risk not just the mental nerve, as in cases with true multiple MF, but also the IAN and the mandibular incisive nerve.

Ultrasound-guided maxillary nerve block: an anatomical study using the suprazygomatic approach

PURPOSE

Although a maxillary nerve (MN) block reportedly provides satisfactory analgesia for midface surgery and chronic maxillofacial pain syndromes, a safe and reliable MN block technique has not been reported. The goal of this anatomical study was to quantify the various angles and depth of the block needle, as well as to evaluate the impact of volume on the extent of injectate spread that might influence anesthetic coverage and block-related complications.

METHODS

Following an ultrasound-guided suprazygomatic MN block with dye injection, a dissection was performed in the pterygopalatine fossa (PPF) of four lightly embalmed cadaveric specimens. Half of the specimens were injected with 5 mL of dye, and the other half with 1 mL of dye. The needle depth was measured from the ultrasound images and using rubber markers. Following injection, dissection was performed to map the area of dye spread.

RESULTS

The median [interquartile range (IQR)] distance from the skin to the PPF was 37 [36-43] mm and 47 [40-50] mm by ultrasound and rubber marker methods, respectively. The median [IQR] needle orientation was 14 [11-32] degrees inferiorly and 15 [10-17] degrees posteriorly. The PPF was consistently dyed in the 5 mL group, but sporadically dyed in the 1 mL group. In the 5 mL group, spread outside of the PPF was seen.

CONCLUSIONS

We showed that 5 mL of injectate far exceeds the capacity of the PPF, leading to drug spread outside of the PPF. Moreover, we found that 1 mL of injectate largely covered the nerve, suggesting a more efficacious and safer block procedure. This finding will need confirmation in future clinical studies.

The maxillary sinus: physiology, development and imaging anatomy

OBJECTIVES

The maxillary sinus is of paramount importance for otolaryngologists, rhinologists, oral and maxillofacial surgeons, head and neck and dental and maxillofacial radiologists. A comprehensive review article concerning the physiology, development and imaging anatomy was undertaken.

METHODS

Relevant literature pertaining to the physiology of the sinonasal cavity, development of the paranasal sinuses and imaging anatomy of the maxilla and maxillary sinus from 2000 to 2019 was reviewed. Emphasis was placed on literature from the last 5 years.

RESULTS

Extensive recent research using imaging has provided new insights into the development of the maxillary sinus, the other paranasal sinuses and the midface. The fundamental physiological concept of mucociliary clearance and its role in sinus health is emphasized. The paranasal sinuses are an integral part of a common mucosal organ formed by the upper and lower airway.An in-depth understanding of the soft-tissue and neurovascular relationships of the maxillary sinus to the deep fascial spaces and branches of the trigeminal nerve and external carotid artery respectively is required to evaluate and report imaging involving the maxillary sinus.Sinusitis of rhinogenic, rather than odontogenic origin, originates from nasal inflammation followed by anterior ethmoid disease and secondary obstruction of the ostiomeatal unit. The role of anatomical variants that predispose to this pattern of disease is discussed in detail with illustrative examples.The maxillary sinus is intimately related to the roots of the posterior maxillary teeth; the high frequency of mucosal disease and sinusitis of odontogenic aetiology is now well recognized. In addition, an understanding of the anatomy of the alveolar process, morphology of the alveolar recess of the maxillary sinus and neurovascular supply are essential both for deliberate surgical intervention of the sinus and complications related to oral surgical procedures.

CONCLUSIONS

An understanding of the fundamental principles of the development, physiology, anatomy and relationships of the maxillary sinus as depicted by multi-modality imaging is essential for radiologists reporting imaging involving the paranasal sinuses and midface.

A mandibular bone defect of uncertain significance: report of a paleopathological case

Anatomical variations of the mandibular canal as well as the presence of accessory canals and foramina are common findings in the human mandible. Here, we present a previously unreported type of anatomical variation, consisting of a large full-thickness bone defect of the right mandibular ramus, observed in a young male unearthed from a mediaeval cemetery located in North-Eastern Italy. The defect was located very close to, yet not directly connected with, the mandibular canal. Awareness of the existence of deviations from the anatomical norm such as that we describe here is strategic to avoid diagnostic misinterpretations, minimise technical hitches, and prevent clinical complications during invasive procedures in the region of the mandible.

Inferior Alveolar Nerve Block Using the Anterior Technique to Anesthetize Buccal Nerve and Improve Anesthesia Success Rates for Third Molar Extraction: A Randomized Controlled Trial and Magnetic Resonance Imaging Evaluation

PURPOSE

The lack of anesthesia to the buccal nerve and an insufficient volume of anesthetic have been reported to be responsible for failed inferior alveolar nerve blocks (IANBs) using the Halsted approach (conventional IANB). We aimed to determine the extent of anesthesia in the buccal nerve innervation area and evaluate the anesthetic efficacy of injecting a larger volume of anesthetic during IANB using the anterior approach (anterior technique) in the clinical setting and with magnetic resonance imaging (MRI) analysis.

PATIENTS AND METHODS

The prospective randomized controlled trial included patients scheduled for removal of a mandibular third molar. The primary predictor variables were the approach for IANB (anterior technique vs conventional IANB) and anesthetic dose (1.8 vs 2.7 mL). The primary outcome variables were the extent of anesthesia and the anesthesia success rate, defined as completion without additional anesthesia. The secondary outcome variable was the anesthetic drug distribution related to the pterygomandibular space measured on T2-weighted MRI scans. Statistical independence of the anesthesia success rate among the primary predictor variables was tested with statistical significance set at P ≤ .05.

RESULTS

A total of 108 patients and 10 volunteers were enrolled in the clinical and MRI studies, respectively. Anesthesia of the buccal nerve was evident in patients receiving the anterior technique with 2.7 mL of anesthetic. The success rate of the anterior technique with 2.7 mL of anesthetic (96%) was greater than that with 1.8 mL of anesthetic (67%; P = .0113), and increasing the dose had no effect on the efficacy of conventional IANB (78% vs 81%; P = 1.000). The MRI study showed that the anesthetic was distributed over the anterior surface of the temporalis tendon and in the pterygomandibular space after the anterior technique.

CONCLUSIONS

Anesthesia of the buccal nerve using the anterior technique with 2.7 mL of anesthetic solution might contribute to increasing the success rate of anesthesia for removal of mandibular third molars.

Mandibular incisive canal and lingual foramina characterization by cone-beam computed tomography

INTRODUCTION

Many patients have haemorrhagic and neurologic complications after surgery at the symphysis region, while this area between the mental foramina is commonly considered to be risk-free because the presence of vasculo-nervous anastomoses found in the mandibular incisive canal (MIC) and lingual foramina (LF). The purpose of our study was to better analyse these anatomical structures to better identify and preserve them during surgery.

PATIENTS AND METHODS

This prospective radio-anatomical study evaluated the presence, morphology and topography of MIC and median LF (MLF) and paramedian LF (PLF) by cone-beam computed tomography according to age, gender and dentition of 50 consecutive patients.

RESULTS

Among the MIC, 99% were visualized at their origin. Their visibility decreased gradually towards the symphysis. The MIC had a larger diameter and followed a significantly more superficial and more vestibular way in older patients. At least, one MLF by hemimandible was found whereas PLF were found only in 68% of the cases. The mean distance from the basal border was 7.11mm for the lower MLF, 16.33mm for the upper MLF and varied from 11.15 to 10.85mm for the left and right PLF.

CONCLUSION

Our study suggests that MIC and LF are constant structures with anatomical variations and that three-dimensional topographic study of the interforaminal region would be beneficial in patients requiring surgery in this area to reduce the risk of haemorrhage and neurologic complications.

Case-control study of mandibular canal branching and tooth-related inflammatory lesions

OBJECTIVES

Morphological variations of mandibular canals increase the risk of neurovascular damage and bleeding during surgical procedures by decreasing the predictability of the inferior alveolar neurovascular bundle location. To improve the predictability with such variations, the present study aimed to verify the possibility of a relationship between mandibular canal branches (MCBs) and tooth-related inflammatory lesions, using trough cone-beam computed tomography (CBCT) examinations.

METHODS

The sample comprised 150 age and sex-matched examinations (50 cases and 100 controls) from two databases. The CBCT examinations were grouped by the presence of MCBs starting in the mandibular body regions as the outcome variable. Tooth-related inflammatory lesions and measurements of gray levels in the posterior region of the alveolar ridge were assessed in both groups. A multiple logistic regression analysis was applied to verify the relationships between MCBs and independent variables (p < 0.05).

RESULTS

Occurrence of tooth-related inflammatory lesions increased the risk of MCBs in the mandibular body regions (p < 0.001; OR 11.640; 95% CI 4.327-31.311). High-contrast images had a weaker association with MCBs (p = 0.002; OR 1.002; 95% CI 1.002-1.003). The most frequent tooth-related inflammatory lesions in both groups were endodontic (34 lesions; 45.94% of the total lesions). Most of the tooth-related inflammatory lesions related to MCBs were endodontic (20 cases) and combined endodontic and periodontal inflammation (20 cases).

CONCLUSIONS

An association was observed between MCBs in the mandibular body regions and tooth-related inflammatory lesions. Inflammatory lesions of endodontic origin are most often associated with MCBs.

Efficacy of intraligamentary anesthesia in maxillary first molar extraction

INTRODUCTION

Infiltration anesthesia (IA) is the method to anaesthetize maxillary teeth successfully. In contrast, intraligamentary anesthesia (ILA) has been used as supplementary anesthesia during tooth extraction, particularly when regional block anesthesia has failed. In this study, we compare the efficacy of and patient satisfaction with ILA vs IA when extracting maxillary first molar teeth.

METHODS

Forty patients were enrolled in this study and 80 maxillary first molars extracted. All patients served as their own control, with ILA as the experimental side and IA as the control side. The two techniques were compared for efficacy using a visual analog scale (VAS) and patient satisfaction compared using a verbal rating scale (VRS).

RESULTS

The mean VAS pain score for extraction using ILA was lower than that for IA (20.30±3.18 and 13.93±1.95 mm, respectively; P<0.001). For injection pain, the mean VAS pain score in the ILA side was higher than the IA side (42.28±4.51 and 31.73±3.1 mm, respectively; P<0.001). VRS results showed a higher number of patients who felt that pain during ILA was greater than expected compared with IA.

CONCLUSION

IA appears less painful during injection compared with ILA, and provides sufficient pain relief during extraction. However, ILA can be used when IA fails to achieve the desired pain suppression, as it provides higher extraction-pain relief.

The Anatomical Nature of Dental Paresthesia: A Quick Review

Dental paresthesia is loss of sensation caused by maxillary or mandibular anesthetic administration before dental treatment. This review examines inferior alveolar block paresthesia symptoms, side effect and complications. Understanding the anatomy of the pterygomandibular fossa will help in understanding the nature and causes of the dental paresthesia. In this review, we review the anatomy of the region surrounding inferior alveolar injections, anesthetic agents and also will look also into the histology and injury process of the inferior alveolar nerve.

Evolution of facial innervation in anomodont therapsids (Synapsida): Insights from X-ray computerized microtomography

Anomodontia was the most successful herbivorous clade of the mammalian stem lineage (non-mammalian synapsids) during the late Permian and Early Triassic. Among anomodonts, Dicynodontia stands apart because of the presence of an osseous beak that shows evidence of the insertion of a cornified sheath, the ramphotheca. In this study, fourteen anomodont specimens were microCT-scanned and their trigeminal canals reconstructed digitally to understand the origin and evolution of trigeminal nerve innervation of the ramphotheca. We show that the pattern of innervation of the anomodont "beak" is more similar to that in chelonians (the nasopalatine branch is enlarged and innervates the premaxillary part of the ramphotheca) than in birds (where the nasopalatine and maxillary branches play minor roles). The nasopalatine branch is noticeably enlarged in the beak-less basal anomodont Patranomodon, suggesting that this could be an anomodont or chainosaur synapomorphy. Our analyses suggest that the presence or absence of tusks and postcanine teeth are often accompanied by corresponding variations of the rami innervating the caniniform process and the alveolar region, respectively. The degree of ossification of the canal for the nasal ramus of the ophthalmic branch also appears to correlate with the presence of a nasal boss. The nasopalatine canal is absent from the premaxilla in the Bidentalia as they uniquely show a large plexus formed by the internal nasal branch of the maxillary canal instead. The elongated shape of this plexus in Lystrosaurus supports the hypothesis that the rostrum evolved as an elongation of the subnarial region of the snout. Finally, the atrophied and variable aspect of the trigeminal canals in Myosaurus supports the hypothesis that this genus had a reduced upper ramphotheca.

Is Inferior Alveolar Nerve Block Sufficient for Routine Dental Treatment in 4- to 6-year-old Children?

Introduction

Pain control is one of the most important aspects of behavior management in children. The most common way to achieve pain control is by using local anesthetics (LA). Many studies describe that the buccal nerve innervates the buccal gingiva and mucosa of the mandible for a variable extent from the vicinity of the lower third molar to the lower canine. Regarding the importance of appropriate and complete LA in child-behavior control, in this study, we examined the frequency of buccal gingiva anesthesia of primary mandibular molars and canine after inferior alveolar nerve block injection in 4- to 6-year-old children.

Study design

In this descriptive cross-sectional study, 220 4- to 6-year-old children were randomly selected and entered into the study. Inferior alveolar nerve block was injected with the same method and standards for all children, and after ensuring the success of block injection, anesthesia of buccal mucosa of primary molars and canine was examined by stick test and reaction of child using sound, eye, motor (SEM) scale. The data from the study were analyzed using descriptive statistics and statistical software Statistical Package for the Social Sciences (SPSS) version 21.

Results

The area that was the highest nonanesthetized was recorded as in the distobuccal of the second primary molars. The area of the lowest nonanesthesia was also reported in the gingiva of primary canine tooth.

Conclusion

According to this study, in 15 to 30% of cases, after inferior alveolar nerve block injection, the primary mandibular molars’ buccal mucosa is not anesthetized.

How to cite this article: Pourkazemi M, Erfanparast L, Sheykhgermchi S, Ghanizadeh M. Is Inferior Alveolar Nerve Block Sufficient for Routine Dental Treatment in 4- to 6-year-old Children? Int J Clin Pediatr Dent 2017;10(4):369-372.

Trigeminocardiac reflex during non-surgical root canal treatment of teeth with irreversible pulpitis

BACKGROUND/PURPOSE

Trigeminocardiac reflex (TCR) is a unique clinical incident of acute change in hemodynamic balance, which may lead to hypotension, bradycardia, and even clinical crisis. Up to date, no study so far considers the impact of non-surgical root canal treatment (NSRCT) of irreversible pulpitis teeth under either local infiltration or block anesthesia on hemodynamic change possibly related to TCR.

METHODS

This study enrolled 111 patients with 138 irreversible pulpitis teeth that were treated by two sessions of NSRCT. The first session involved mainly the removal of vital pulp tissue with the direct stimulation of the dental branches of the trigeminal nerve, and the second session included the root canal enlargement and debridement with minimal disturbance to the dental branches of the trigeminal nerve. Vital signs mainly the blood pressure were recorded during both NSRCT sessions.

RESULTS

The incidences of NSRCT patients with MABP decrease ≧10%, ≧15%, or ≧20% were all significantly higher in the first NSRCT session than in the second NSRCT session (all the P-values < 0.001). In the first NSRCT session, the incidence of patients with MABP decrease ≧10% was significantly associated with tooth type. For both upper and lower teeth, the patients with premolars treated by NSRCR had significantly higher incidences of MABP decrease ≧10% than those with either anterior or molar teeth treated by NSRCR (all the P-values < 0.05).

CONCLUSION

We conclude that vital pulp extirpation may lead to a substantial drop in patient's blood pressure possibly related to TCR.

Aberrations Causing Neurovascular Damage in the Anterior Maxilla during Dental Implant Placement

When dental implants are being considered for placement in the maxillary central incisor region, proximity to the nasopalatine canal and its contents needs to be accounted for. The morphology of the canal changes with age. The availability of CBCT has allowed the in-depth analysis of this important variable anatomy. However, an associated important anatomical structure can be easily overlooked: the “canalis sinuosus.” This is a neurovascular canal carrying the anterior superior alveolar (ASA) nerve and artery. CBCT frequently shows the canalis sinuosus (CS) as a wide canal lateral to the nasal cavity and also under the anterior part of the nasal floor in close proximity to the NPC. The CS distributes both neural supply and vascular supply to the maxillary anterior teeth which on CBCT sagittal analysis are seen as very fine circular canals having nondistinct walls. The author presents a case history of dental implant placement in the anterior maxilla which resulted in neurovascular disturbance as a result of invasion of the nasopalatine duct and injury to its contents together with the unidentified injury to an aberrant well-defined neurovascular canal inferior to the canalis sinuosus.

The prevalence of mandibular retromolar canals on cone beam computed tomography and its clinical repercussions

Abstract Introduction Knowledge on the normal morphology of the human mandible and its possible anatomical variations are of fundamental importance in dental practice, especially in the areas of surgery and implantodontics. The retromolar region is delimited by the anterior margin of the ramus of the mandible, the temporal crest and the distal surface of the last lower molar. In this area, a retromolar canal may be observed emerging through the retromolar foramen. Objective This study aims to evaluate the prevalence of retromolar canals in cone beam computed tomography (CBCT) images and to correlate it with their possible clinical repercussions. Material and method 300 CBCT images were selected from the Department of Radiology of the São Leopoldo Mandic Dental School. This was an observational descriptive study and all the images were processed and analyzed on XoranCat®. Result Of the 300 CFCT scans analyzed, a single mandibular canal was observed in 210 (70.0%). In the remaining 90 cases, anatomical changes were observed relating to this canal, indicating that the prevalence of this condition in this sample was 30%. The prevalence of retromolar canals was observed in 15 patients (5.0%), of which 06 were in males and 09 in females. Conclusion The importance of a full knowledge on the anatomy of the retromolar region is herein reiterated due to the high prevalence of surgical procedures in the posterior region of the mandible, which could optimize predictability at treatment planning as well as anesthetic and surgical outcomes, thus minimizing anesthetic failures and surgical accidents.

Digital design of functional surgery for odontogenic cyst intruding into maxillary sinus

INTRODUCTION

Traditional Caldwell-Luc approach needs modifications for odontogenic cysts intruding into the maxillary sinus, to preserve sinus mucosa and bony contour. Recently, digital technology has been widely applied to the field of maxillofacial surgery, guiding the surgical plan and improving its accuracy.

OBJECTIVE

This study attempted to present and evaluate the functional surgery of odontogenic cysts intruding into the maxillary sinus using a computer-assisted pre-surgical design.

METHODS

Consecutive patients with odontogenic cysts intruding into the posterior part of the maxillary sinus were enrolled. Method I "Bony wall reimplantation method" was performed for large lesions exceeding the zygomatic alveolar crest but without apparent bone destruction of the anterior wall of the sinus, while Method II "bone removal method" was more convenient for small lesions near to the zygomatic alveolar crest. The gap was filled with a pedicled buccal fat pad after lesion removal and all cases were without inferior meatal antrostomy.

RESULTS

A total of 45 cases were included in the study. 22 were operated using method I while 23 were operated with method II. Operations were completed in 20min. Pain disappeared in 3.62 days on average, and swelling 6.47 days. Nasal bleeding occurred in 8 patients lasting 1-3 days. Suppurative inflammation was observed in 1 patient, and infection occurred after bone reposition. Other repositioned free bony wall was without resorption in CT images.

CONCLUSIONS

Sinus mucosa and bony wall should be conserved. Preoperative digital design can guide osteotomy effectively during the surgery. Bone reposition is not suitable for suppurative inflammation. The pedicled buccal fat pad is enough for drainage and inferior meatal antrostomy is not necessary.

Efficacy of Exclusive Lingual Nerve Block versus Conventional Inferior Alveolar Nerve Block in Achieving Lingual Soft-tissue Anesthesia

Objective:

The aim of this randomized clinical trial was to assess the efficacy of exclusive lingual nerve block (LNB) in achieving selective lingual soft-tissue anesthesia in comparison with conventional inferior alveolar nerve block (IANB).

Materials and Methods:

A total of 200 patients indicated for the extraction of lower premolars were recruited for the study. The samples were allocated by randomization into control and study groups. Lingual soft-tissue anesthesia was achieved by IANB and exclusive LNB in the control and study group, respectively. The primary outcome variable studied was anesthesia of ipsilateral lingual mucoperiosteum, floor of mouth and tongue. The secondary variables assessed were (1) taste sensation immediately following administration of local anesthesia and (2) mouth opening and lingual nerve paresthesia on the first postoperative day.

Results:

Data analysis for descriptive and inferential statistics was performed using SPSS (IBM SPSS Statistics for Windows, Version 22.0, Armonk, NY: IBM Corp. Released 2013) and a P < 0.05 was considered statistically significant. In comparison with the control group, the study group (LNB) showed statistically significant anesthesia of the lingual gingiva of incisors, molars, anterior floor of the mouth, and anterior tongue.

Conclusion:

Exclusive LNB is superior to IAN nerve block in achieving selective anesthesia of lingual soft tissues. It is technically simple and associated with minimal complications as compared to IAN block.

Insight of Dogs' Inner Mandible Anatomy using Mathematical Models

This study was performed in a sample of 20 dogs (n = 20) and aimed to: (1) characterize the mandible height (Mh), mandibular canal height (MCh) and distance between the inter-dental alveolar margin and the mandibular canal (dIAM-MC) dimensions, and (2) to develop mathematical models that express the insight's mandible anatomy of those important mandible structural elements allowing the prediction of their dimensions using physical parameters such as patient body weight (Wg) and the canine tooth width at the free gingival margin level-(wCGM). Lateral-view X-rays of both sides of the skull were taken for all the individuals. Three mathematical prediction models were developed to calculate Mh, MCh and dIAM-MC. Achieved proportions of the mandible considered parameters regarding its height were of 36.45% for MCh, 50.90% for dMAI-MC and 12.65% for vMC. Statistically significant differences were registered between the Wg and wCGM (P = 0.00), Mh (P = 0.00), MCh (P = 0.00) and dIAM-MC (P = 0.00). Only the Wg presented a strong correlation with the wCGM (R = 0.58), Mh (R = 0.70), dIAM-MC (R = 0.60) and MCh (R = 0.68). These models will allow a clinician to estimate the size of the mandible structures by only using data obtained during the physiological examination, with a sufficiently high prediction capacity and a very low standard error. The study points out the relationships of physiological parameters such as Wg and wCGM with mandible anatomical structural elements considered as important in oral surgery. The results of this study give the surgeon a new additional tool providing more information on the mandible anatomical structures and its relationships. This reduces the risk of iatrogenic lesions during the oral surgical procedures and improves patient safety.

Variant Inferior Alveolar Nerves and Implications for Local Anesthesia

A sound knowledge of anatomical variations that could be encountered during surgical procedures is helpful in avoiding surgical complications. The current article details anomalous morphology of inferior alveolar nerves encountered during routine dissection of the craniofacial region in the Gross Anatomy laboratory. We also report variations of the lingual nerves, associated with the inferior alveolar nerves. The variations were documented and a thorough review of literature was carried out. We focus on the variations themselves, and the clinical implications that these variations present. Thorough understanding of variant anatomy of the lingual and inferior alveolar nerves may determine the success of procedural anesthesia, the etiology of pathologic processes, and the avoidance of surgical misadventure.

Palaeoneurological clues to the evolution of defining mammalian soft tissue traits

A rich fossil record chronicles the distant origins of mammals, but the evolution of defining soft tissue characters of extant mammals, such as mammary glands and hairs is difficult to interpret because soft tissue does not readily fossilize. As many soft tissue features are derived from dermic structures, their evolution is linked to that of the nervous syutem, and palaeoneurology offers opportunities to find bony correlates of these soft tissue features. Here, a CT scan study of 29 fossil skulls shows that non-mammaliaform Prozostrodontia display a retracted, fully ossified, and non-ramified infraorbital canal for the infraorbital nerve, unlike more basal therapsids. The presence of a true infraorbital canal in Prozostrodontia suggests that a motile rhinarium and maxillary vibrissae were present. Also the complete ossification of the parietal fontanelle (resulting in the loss of the parietal foramen) and the development of the cerebellum in Probainognathia may be pleiotropically linked to the appearance of mammary glands and having body hair coverage since these traits are all controlled by the same homeogene, Msx2, in mice. These suggest that defining soft tissue characters of mammals were already present in their forerunners some 240 to 246 mya.

Location and classification of Canalis sinuosus for cone beam computed tomography: avoiding misdiagnosis

The aim of this study was to assess the presence, location and, multiplanar distance of the canalis sinuosus (CS) between the incisive foramen and the anterior maxillary alveolar ridge using cone beam computed tomography (CBCT). Therefore, 500 CBCT maxillary images obtained from male and female patients aged 20 to 80 years were selected to assist in the dental treatment. Low-quality tomographic images were discarded. All images were captured with the i-CATTM Classic tomograph and assessed using the XoranCatTM software. The axial sections were analyzed at the incisive foramen in order to verify the CS presence in laterality and location. Furthermore, linear measurements of the nasal cavity floor, buccal cortical bone, and alveolar ridge crest were made. All the collected data were statistically analyzed. Results show a variation of the CS in relation to the classification and distance of anatomical structures, but no significant difference between the right and left sides. It should be highlighted that CBCT is necessary before invasive procedures in order to preserve important anatomical structures. In conclusion, the location of the CS varies in relation to the alveolar ridge crest and buccal cortical bone, assuming that it is going to be located by the upper lateral incisor palatine.

Retromolar Canal Associated with Age, Side, Sex, Bifid Mandibular Canal, and Accessory Mental Foramen in Panoramic Radiographs of Brazilians

Background. The retromolar canal (RMC) is an anatomical variation that can cause complications in dental procedures. Method. The RMC was evaluated according to age, sex, and presence of accessory mandibular canal and accessory mental foramen, on both sides in 500 panoramic radiographs, belonging to individuals at the age of 7 to 20 years. The associations of interest were studied through Fisher's Exact Test and Pearson's Chi-Square Test, and the correlation was studied through Pearson's Correlation Coefficient (r). The significance level used was 5%. Results. The RMC was observed in 44 radiographs (8.8%), and out of those 24 were females. There was no statistically significant association between the RMC and age (p > 0.05; Fisher's Exact Test), sex (p = 0.787; Pearson's Chi-Square Test), amount of mandibular canals and mental foramina, on both sides (p > 0.05; Pearson's Chi-Square Test). There was a significant association between RMC and side, the higher frequency of the canal being on the right side (p < 0.05; Fisher's Exact Test). Conclusions. Despite the low occurrence of the RMC, its identification and the verification of its dimensions and path are relevant, mainly in cases when anesthetic and surgical procedures can present failures or difficulties.