Canalis sinuosus: anatomical variation or structure?

Evaluation of canalis sinuosus and accessory canal morphology by cone-beam computed tomography

OBJECTIVE

To evaluate canalis sinuosus (CS) and accessory canalis sinuosus (AC) morphology and their relationship with the impacted canine on cone-beam computed tomography (CBCT) images.

METHODS

The diameter and location of the CS, its distance from the nasal cavity (NC-CS), its distance from the buccal cortical plate (BC-CS), and its distance from the alveolar ridge crest (AR-CS) were evaluated on 1000 CBCT scans. The prevalence and termination of AC and the presence of impacted canines were also evaluated.

RESULTS

CS was detected in 89 (8.9%) of 1000 CBCTs. The mean CS diameter was found as 1.34 ± 0.53 mm. No statistically significant difference was found between gender, age, direction, and CS presence and diameter. CS was most frequently seen in regions 11 (23.6%) and 13 (23.6%). The average NC-CS, BC-CS, and AR-CS length was 6.14, 6.06 and 4.35 mm, respectively. AC was detected in 22 patients (24.71%). There was no statistically significant difference between the presence of AC and gender, age, CS diameter, NC-CS, BC-CS, and AR-CS distance. BC-CS length and AR-CS length were statistically significantly higher in patients with impacted canines.

CONCLUSIONS

It should be kept in mind that the CS diameter, NC-CS, BC-CS, and AR-CS distance may increase in the presence of an impacted canine and the integrity of the neurovascular structure should be preserved. The fact that the CS is often localized in the palatial region requires a detailed evaluation of the anterior maxillary region with three-dimensional imaging methods.

Canalis Sinuosus Mimicking Periapical Pathology on, Radiographic Assessment

The canalis sinuosus is an anatomical variation whereby the infraorbital canal sometimes generates a small, lateral branch (canal) close to its midpoint, to allow the passage of the anterior superior alveolar neurovascular bundle in the anterior maxilla. This article focuses on an incidental finding of this variant, in a 74-year-old Trinidadian female of Afro-Caribbean descent with an endodontic presenting complaint. The canalis sinuosus shadow on conventional radiography resulted in uncertainty as to the offending tooth until a 3-dimensional scan was undertaken in this region. This report will discuss the implications of the presence of this canal from radiologic, endodontic, and surgical perspectives.

Retrospective evaluation and descriptive analysis of the prevalence of anatomical structures and variations in CBCT images before dental implant planning in a group Turkish population, part I

PURPOSE

The aim of this study is to emphasize the importance of using cone-beam computed-tomography in order to determine the anatomical structures and their variations before the treatment in patients who apply to the dentist clinic for implant treatment.

METHODS

In the study, CBCT images of 500 adult patients (240 female and 260 male), aged between 21 and 82 years, who applied for implant treatment due to missing teeth, were retrospectively analyzed. Anatomical structures and variations such as nasopalatine canal(NPC), canalis sinuosus(CS), antral alveolar artery(AAA), were evaluated in multiplanar reformation(MPR) sections which are axial, sagittal and coronal can be viewed in consistence with each other.

RESULTS

The incidence of anatomical variation of CS in the right region was similar according to gender. The "Funnel" appearance of the NPC shape was found most common shape in both female and male patients (n = 89; 37.1% for females and n = 71; 27.3% for males).

CONCLUSION

CBCT has become the most popular 3D imaging method in dental practice especially for planning dental implants. Understanding the relationship with important anatomical structures before implant applications is crucial in dealing with potential complications that may arise afterward. Assessing significant anatomical structures by CBCT and taking precautions against possible risks facilitate the work of dentists during and after procedures.

A cone-beam computed tomography study of canalis sinuosus and its accessory canals in a South African population

OBJECTIVES

Canalis sinuosus (CS) is a clinically relevant structure in the anterior maxilla. The present study aimed to determine the prevalence and distribution of CS and its accessory canals (ACs) in the South African population and describe its anatomical variations.

METHODS

In total, 500 cone-beam computed tomography (CBCT) scans of the anterior maxilla were assessed for prevalence, sidedness, diameter, and distribution of CS. The frequency, number, diameter, configuration, and point of termination of ACs were also recorded. Statistical analysis was performed using analysis of variance, Kruskal-Wallis, chi-squared, and Fisher Exact tests with P < 0.05.

RESULTS

CS was present in most cases (99.6%), and commonly occurred bilaterally (98.8%). The mean diameter of CS was 1.08 mm (range: 0.50 mm-2.39 mm). Sex, population group, and age had no significant effect on the prevalence or sidedness of CS. Additionally, 535 ACs were observed in 58.8% of the sample, with 42.9% of ACs found bilaterally and 57.1% unilaterally. The mean diameter of the ACs was 0.86 mm on the left and 0.87 mm on the right (range; 0.50 mm-1.52 mm). The majority of ACs maintained a straight vertical configuration (72.3%). ACs most commonly terminated in the anterior palatal region of the maxilla (57.2%). No significant differences were found in any groups mentioned (P > 0.05).

CONCLUSIONS

A high prevalence of CS as well as ACs were observed in the sample population. Due to their clinical significance, surgical planning with the aid of high quality CBCT scans of the anterior maxilla is advisable.

Anatomy and function of the canalis sinuosus and its injury prevention and treatment strategies in implant surgery

The canalis sinuosus, a canal containing the anterior superior alveolar nerve bundle, originates from the infraorbital canal and extends along the maxillary sinus and nasal cavity edges to the anterior maxilla. It was once regarded as an anatomical variation. However, with the widespread application of cone beam computed tomography (CBCT), the detection rate of canalis sinuosus in the population has increased. The canalis sinuosus exhibits diverse courses, branching into multiple accessory canals and terminating at the nasal floor or the anterior tooth region, with the majority traversing the palatal side of the central incisor. The anterior superior alveolar nerve bundle within the canalis sinuosus not only innervates and nourishes the maxillary anterior teeth, their corresponding soft tissues, and the maxillary sinus mucosa, but also relates to the nasal septum, lateral nasal wall, and parts of the palatal mucosa. To minimize surgical complications, implantologists need to investigate strategies for preventing and treating canalis sinuosus injuries. Preoperatively, implantologists should use CBCT to identify the canalis sinuosus and virtually design implant placement at a distance of more than 2 mm from the canalis sinuosus. Intraoperatively, implantologists should assess bleeding and patient comfort, complemented by precision surgical techniques such as the use of implant surgical guide plates. Postoperatively, CBCT can be employed to examine the relationship between the implant and the canalis sinuosus, and treatment of canalis sinuosus injuries can be tailored based on the patient's symptoms. This review summarizes the detection of canalis sinuosus in the population, its anatomical characteristics, and its physiological functions in the anterior maxilla, and discusses strategies for effectively avoiding canalis sinuosus injuries during implant surgery, thereby enhancing implantologists' awareness and providing references for clinical decision-making.

Assessment of canalis sinuosus, rare anatomical structure using cone-beam computed tomography: A prospective study

Objectives

This prospective study was performed with cone-beam computed tomography (CBCT) images for evaluating canalis sinuosus (CS), determine its location and diameter in relation to gender, age, and distances from important structures, including floor of nasal cavity, incisive foramen, edge of buccal cortical bone, and palatal cortical bone.

Material and Methods

The scans of 650 patients in total were included in this prospective analysis. Gender, age, the position of the CS, its presence or absence, diameter, and its location in reference to the adjacent teeth were the factors that were noted.

Results

The study had 301 female participants and 349 male participants, with a mean age of 42.19. Compared to females, males had a statistically higher frequency of CS. Higher age groups showed a higher presence of CS in comparison to the other age groups. The mean distances of these parameters on the left and right side did not differ significantly. Nonetheless, the distance on both sides between CS and nasal cavity floor for males and females, as well as the diameter and border of buccal-palatal cortical bone on the right side, were statistically significant different. On the left side, both genders demonstrated significance in buccal cortical margin and nasal cavity floor. IIn addition, in females, the diameter of the CS on the right and left sides differed on average. The associations between age and number of CS, CS diameter, and number of CS versus sex were all extremely weak. Overall, the study findings showed that CS is a typical anatomical feature in anterior maxillary region, irrespective of age, or gender.

Conclusion

The bony canal, CS is an obscure feature located in the frontal region of the maxilla. Surgeons can avoid complications by being aware of the auxiliary canals derived from this structure. With the use of CBCT, it is now feasible to examine the course of CS as it passes through the maxillary sinus's anterolateral wall with better radiological accuracy has already been documented.

Anatomical variations and abnormalities of the maxillary region and clinical implications: A systematic review and metaanalysis

OBJECTIVE

The objective of this review is to investigate and analyze the anatomical variations present in the maxillary sinus (MS), through the examination of the prevalence of these variations, as well as the corresponding prevalence of clinically significant pathologies and complications associated with them.

METHODS

The search process was carried out in the following databases; MEDLINE, SCIELO, WOS, CINHAL, SCOPUS, and GOOGLE SCHOLAR, using as search terms; "Maxillary bone," "Maxillary sinus," "Paranasal sinus," "Anatomical variations," "Sinusitis" and "Clinical anatomy."

RESULTS

A total of 26 articles and 12969 samples were included, from which 12,594 subjects had their sex recorded giving a total of 5802 males and 6792 females. The variants reported by the included were Haller cells, Concha Bullosa, Number of septa, Hypoplastic sinus, Agger Nasi, Thickening of the MS mucosa, Deviation of the nasal septum, Accessory ostium, and Onodi cells. Among the mentioned, the ones that presented the greatest number of studies (between 8 and 10 studies included) were: the Haller Cells, the Concha Bullosa, and the Number of septa, where prevalence was 0.30, 0.36, 0.39 respectively. These variations can lead to sinusitis, cause some types of tumors, or affect neighboring structures that could be compromised by this variation.

CONCLUSION

As a result, it is certainly complex to distinguish the presence of anatomical variations from pathological abnormalities. Therefore, knowledge of the different variations and their clinical relationships could be a useful asset for clinicians dedicated to this region.

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.

Neurological Risks During Implant Placement in the Anterior Maxilla and Mandible: A Literature Review

The placement of implants in the anterior maxillary and mandibular region requires esthetic proficiency and surgical finesse. It is important to consider the esthetic outcome while avoiding any type of nerve injury for the patient. In this literature review, anatomical structures of the anterior jaw were reviewed from a gross anatomical and radiographic interpretation. A discussion on the frequency of neurosensory complications for patients as a result of nerve damage in this region was evaluated. The purpose of this literature review was to educate the dental surgeon to consider the anterior jaw's neurological structures when performing procedures like implant surgery. The mandibular incisive canal (MIC) presents as an extension of the inferior alveolar canal that runs between the mental foramina. The MIC is a structure that is easily depicted in cone-beam computed tomography (CBCT) imaging and is present in most subjects in gross anatomical studies. The anterior loop of the mental nerve is another structure that is discussed in this paper. Although its structure is accurately depicted in CBCT images, its anatomical variations in patients can make implant treatment planning difficult. The maxilla contains 2 neurovascular structures that were discussed. First, the nasopalatine canal and its relation and impact on implant placement is evaluated. Case reports are reviewed that outline a prophylactic enucleation and bone grafting of the canal prior to implant placement. Second, the canalis sinuosus, which houses the anterior superior alveolar nerve, is of concern during implant placement in the lateral incisor region. Case reports involving nerve damage with follow-up are discussed.

Assessment of Canalis Sinuosus located in maxillary anterior region by using cone beam computed tomography: a retrospective study

Background

The aim of the study is to determine the distribution, location, diameter, and distance measurements of Canalis Sinusosus (CS) in relation with age and sex.

Methods

300 Cone-Beam Computed Tomography (CBCT) images were evaluated. The distance between CS and nasal cavity floor (NCF), buccal cortical bone margin (BCM), alveolar ridge (AR), respectively.The presence of CS smaller than 1 mm, and the diameter of CS larger than 1 mm were determined. Accessory canals (AC) were classified according to their position relative to the teeth.

Results

435 CS with a diameter of at least 1 mm and 142 CS < 1 mm were identified. The most frequently observed location of CS was the region of the right central incisors. The mean diameter of the canals ( CS ≥ 1) was 1.31 ± 0.19 on the right side and 1.29 ± 0.17 on the left side. No gender differences were found in canal diameter were observed (p > 0.05). There was no significant difference between men and women in the distance between CS and the NCF on the right side, and a significant difference was found in the distance of CS-NCF on the left side (p = 0.047). There were no significant differences between age groups in all parameters.

Conclusion

CBCT is a useful tool for identifying CS. Location and diameter of ACs could not be associated with a specific age group or sex.

Anatomical variations and accessory structures in the maxilla in relation to implantological procedures: an observational retrospective study of 212 cases using cone-bean computed tomography

PURPOSE

This study used cone-beam computed tomography (CBCT) to analyze the prevalence of several maxillary anatomical/accessory structures, as well as variations within each type, assessing how accurate diagnosis can minimize the risk of intraoperative complications during implantological procedures in the oral cavity.

METHODS

212 CBCT scans of the maxilla were analyzed, captured over a period of 18 months for surgical planning purposes. The prevalence of posterior superior alveolar arteries (PSAA), maxillary sinus septa (MSS), and branches of the canalis sinuosus (CS) were evaluated, as were the diameter and location of each anatomical structure in horizontal and vertical planes. P < 0.05 was considered statistically significant.

RESULTS

PSAAs were observed in 99.1% of cases, the intrasinus type being the most frequent; MSS were noted in 15.6% of the sample, mainly in the posterior region with sagittal orientation; CS branches were observed in 50% of patients, mainly in relation to the incisors and significantly more prevalent among males.

CONCLUSIONS

The use of CBCT significantly increases the possibility of clearly identifying these anatomical structures. The differences found between patients highlight the importance of carrying out an exhaustive radiological study of the individual to prevent complications, such as Schneiderian membrane perforation, neurovascular damage or bleeding during surgery.

Assessment of the knowledge of canalis sinuosus amongst dentists and dental students: An online-based cross-sectional study

INTRODUCTION

Canalis sinuosus (CS) is a neurovascular canal that corresponds to a small branch of the infraorbital canal. This study aimed at assessing the knowledge and detection performance of CS amongst dentists and dental students.

MATERIALS AND METHODS

Four-hundred and five dentists and dental students answered a questionnaire with three parts: 1. Socio-demographical; 2. Clinical cases with cone- beam computed tomography (CBCT) sections showing CS and 3. Previous knowledge about CS. The chi-squared test and Spearman's correlation test were used to compare results as appropriate. p-values below .05 were considered statistically significant.

RESULTS

Most participants did not identify CS in any CBCT. There was an association between the number of correct answers and dental specialties. Most individuals had not learned about CS previously. There was an association between past knowledge of CS and gender, highest academic degree, working environment, dental specialty and number of correct answers but not with age or experience in Dentistry.

CONCLUSION

This study suggests that most dentists are not aware about CS and do not know how to diagnose it. Previous knowledge about CS positively influenced its identification in CBCT.

Prevalence, Radiographic Features and Clinical Relevancy of Accessory Canals of the Canalis Sinuosus in Cypriot Population: A Retrospective Cone-Beam Computed Tomography (CBCT) Study

Background and Objectives: This retrospective study aims to evaluate the prevalence, radiographic features, and clinical relevancy of the accessory canals (AC) of the canalis sinuosus (CS) in patients referred for implant surgery. Materials and Methods: Cone-beam computed tomography (CBCT) images of the patients were collected and ACs were evaluated. Age, sex, bilateral distribution, localization, diameter, distance to the buccal cortical plate, distance to the crest of the alveolar ridge, terminal ending localization, and the presence of tooth or implant were recorded. Ninety-one patients who were eligible for this study were enrolled. Results: A total of 188 ACs were found in 91 patients with 86 bilateral and 5 unilateral distributions. The mean age of the patients was 45.39. All ACs had a terminal ending at the palatal cortical border. All parameters showed a non-normal distribution; thus, the Mann–Whitney U test was preferred. Bilateral AC distribution (p = 0.761), AC distance to the crest of the alveolar ridge (p = 0.614), AC distance to the buccal cortical plate (p = 0.105), and AC diameter (p = 0.423) showed no significant difference between females and males. According to our study, a CS might be an anatomical structure rather than an anatomical variation, as all patients had at least one AC of the CS. It can be inferred that the detection of ACs will be achievable once clinicians are aware of these structures with continuous regular anatomy reworks and with small voxel-sized CBCT devices. Conclusion: This study was conducted to find the features and prevalence of the CS, and it was found that the CS is an anatomical structure rather than an anatomical variation. This argument is in line with the information on the CS in Gray’s Anatomy, 42nd Edition. Impaired healings and complications of the CS can be avoided if clinicians follow the American Academy of Oral and Maxillofacial Radiology guidelines regarding pre-operative implant examination. Otherwise, avertible complications may cause significant impairments in quality of life.

Prevalence of canalis sinuosus and accessory canals of canalis sinuosus on cone beam computed tomography: a systematic review and meta-analysis

The aim of this systematic review was to determine the prevalence of the canalis sinuosus (CS) and accessory canals of the canalis sinuosus (ACCS) as identified on cone beam computed tomography (CBCT). Online searches were conducted in the MEDLINE (via PubMed), Scopus, LILACS, Cochrane CENTRAL, Web of Science, and SIGLE (via OpenGrey) databases. Primary studies that determined the prevalence of canalis sinuosus and/or its anatomical variations using CBCT were included. The risk of bias assessment was performed using the AQUA tool. The quality effects model using double arcsine transformation was used for the meta-analysis of prevalence. Heterogeneity, publication bias, and sensitivity analyses were performed. Of 3237 initial results, 17 papers were included for systematic review. The meta-analysis comprising 1994 patients showed a pooled prevalence of CS of 0.80 (95% confidence interval (CI) 0.51-0.99; P = 0.001; I² = 99%). Publication bias analysis revealed minor asymmetry (LFK index 1.84). The meta-analysis of 4605 patients showed a pooled prevalence of ACCS of 0.54 (95% CI 0.38-0.69; P = 0.001; I² = 99%). The sensitivity analysis showed a pooled prevalence of ACCS of 0.53 (95% CI 0.32-0.74; P = 0.001; I² = 99%) for studies with ≥ 1000 patients and 0.55 (95% CI 0.33-0.76; P = 0.001; I² = 98%) for studies with< 1000 patients. Canalis sinuosus showed a pooled prevalence of 0.80 and ACCS showed a pooled prevalence of 0.54; hence both should be considered as anatomical structures, which means that they are present in most people. Surgeons must be aware of the CS and ACCS on CBCT analysis during pre-surgical planning. PROSPERO REGISTRATION NUMBER: CRD42020154195.

Examination of Canalis Sinuosus using Cone Beam Computed Tomography in an Australian Population

BACKGROUND

Canalis sinuosus (CS) and its relationship with adjacent teeth is relevant for surgery in the anterior maxilla. Therefore, the aim of this study was to report the prevalence, characteristics, and variations of CS.

METHODS

Cone beam computed tomography (CBCT) scans of the anterior maxilla of 201 patients were reviewed. CS and the adjacent teeth were analysed by age, sex, and scan resolution, using analysis of variance, chi-squared and Fisher's exact tests. The widest and narrowest diameters of CS, and distance to tooth apex (DTA), were compared by quadrant, closest tooth, and location, and the associations were examined statistically with P < 0.05.

RESULTS

In the 201 scans, 412 CS were identified in 198 patients associated with 395 different teeth. Mean widest diameter was 1.08 ± 0.39 mm (range: 0.42-2.60 mm), while the narrowest diameter was 0.71 ± 0.26 mm (range: 0.25-1.59 mm), and mean DTA of 2.16 ±1.25 mm (range: 0-6.22 mm). CS detection was significantly lower with CBCT taken at resolution size of 0.250 voxels (P = 0.02).

CONCLUSIONS

CS was very common in the anterior maxilla. Clinicians would be well advised to identify this anatomical structure using CBCT before undertaking any surgery in the anterior maxilla. © 2022 Australian Dental Association.

The Role of Morphometric Characteristics of Anterior Maxilla in Planning the Interventions Accompanied by Orthodontic Teeth Movement – An Overview

The anterior maxilla or premaxilla is part of the upper jaw and the most significant content of this region, from the aspect of orthodontic therapy, are the incisor teeth. The frequency of complications during orthodontic movement of the upper incisors refers to a more detailed evaluation of the anatomical structures of the premaxilla. The aim of this study was to investigate morphological and morphometric characteristics of the anterior maxilla by cone beam computed tomography, which could be of interest for planning orthodontic teeth movement. By reviewing the available literature, we compared the values of the alveolar bone height, the distance between the alveolar crest and enamel – cement boundary, total alveolar bone width, the thickness of the buccal, and palatal plate, nasopalatine canal, and accessory canals of the anterior maxilla. The results of our study show changes in the labial and palatal aspects of the alveolar bone height during orthodontic interventions. Different results of the alveolar bone width are in correlation with gender, age, and type of orthodontic tooth movement. Distance between the nasopalatine canal and maxillary central incisors was estimated at the value from 4 to 6 mm, which is below the recommended value for maximum incisal retraction by Proffit. Research results show variations in shape, length, and diameter of the nasopalatine canal, which indicates individual varieties detected on cone beam computed tomography. Other anatomical structures and measures show an insignificant correlation with orthodontic teeth movement. According to the contradictory results of the available articles, it is required to achieve an individual approach to orthodontic interventions in the area of the anterior maxilla.

Morphological and Morphometric Characteristics of Anterior Maxilla Accessory Canals and Relationship with Nasopalatine Canal Type-A CBCT Study

This study aimed to evaluate principal morphological and morphometric characteristics of accessory canals (ACs) of the anterior maxilla, as well as to analyze the relationship with nasopalatine canal (NPC) type. The results of our study showed that ACs were observed in almost 50% of participants. They were mostly presented bilaterally and in a curved shape, with a palatal foramen position. The morphometric characteristics of ACs were significantly influenced by NPC type. NPC type had the strongest impact on the distance between the NPC and AC, as well as on the distance between the AC and the facial aspect of buccal bone wall, in inferior parts of the alveolar ridge. On the other hand, the distance between the AC and central incisors was not significantly influenced by NPC shape in the lower region of the anterior maxilla. However, the participants with the banana-type of the NPC expressed the reduction in distance from the AC to the central incisor at the upper part in comparison with the subjects with the cylindrical-type of the NPC. On the basis of the results of this study, the simultaneous estimation of ACs and the NPC seems reasonable, as this approach may be useful in the prevention of complications which could occur during implant surgery interventions.

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.

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.