Canalis sinuosus: An Anatomic Repair that May Prevent Success of Dental Implants in Anterior Maxilla

[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 and the 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, strategies for preventing and treating canalis sinuosus injuries need to be investigated. Preoperatively, CBCT is used to identify the canalis sinuosus and to virtually design implant placement at a distance of more than 2 mm from the canalis sinuosus. Intraoperatively, assessing bleeding and patient comfort, complemented by precision surgical techniques such as the use of implant surgical guide plates. Postoperatively, CBCT is used 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 the physiological functions in the anterior maxilla, and discusses strategies for avoiding canalis sinuosus injuries during implant surgery, thereby enhancing clinical awareness and providing references for clinical decision-making.

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.

Cone-beam computed tomography of accessory canals of the canalis sinuosus and analysis of the related risk factors

PURPOSE

Cone-beam computed tomography (CBCT) was used in this study for evaluating the diameter, prevalence, spatial location, and risk factors of the accessory canal (AC) of the canalis sinuosus.

METHODS

A comprehensive assessment of the incidence rate, diameter, three-dimensional (3D) spatial location, and direction of travel of AC was performed on 1003 CBCT images. The CBCT data were used to reconstruct a 3D model of the maxilla to determine the alveolar bone volume. The obtained data were further analyzed and processed.

RESULTS

AC was present in 50.1% of images. Male patients more frequently had ACs than female patients did (P < 0.01) and was positively correlated with the maxillary alveolar bone volume (P < 0.001, OR 1.532). Age or nasopalatine canal diameter were not significantly associated with the occurrence of AC (P > 0.05). Among the 502 patients with AC, AC was present on the left side, right side, and bilaterally in 189, 98, and 215, respectively. The maximum number of ACs observed per individual was eight. The average AC diameter was 0.89 ± 0.26 mm (minimum, 0.5 mm; maximum, 2.02 mm).

CONCLUSIONS

As the prevalence of AC and its trajectory display considerable variation among individuals, surgeons must consider the possibility of the presence of AC when devising surgical plans involving the anterior maxillary region.

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.

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.