Treatment of Class II malocclusion with a customized lingual appliance combined with a Class II corrector.

Correcting a complete Class II malocclusion in an adult patient can be quite difficult. If the patient has a large skeletal discrepancy, orthognathic surgery is the treatment of choice. However, if the discrepancy is small or if the situation is borderline and the mandibular incisors are retroclined, Class II correctors can be used. This clinical report presents the orthodontic treatment of a 24-year-old woman with Class II malocclusion. Clinically, her maxilla was slightly protruded, and the mandible was well-positioned. She had uprighted maxillary and mandibular anterior teeth and a deepbite, and she opted for a more esthetically appealing orthodontic appliance. The treatment plan included leveling and alignment of the teeth in both arches, Class II correction, establishing Class I molar and canine relationships, correction of overbite and overjet, adjustment of midlines, and improvement of facial and dental esthetics. Orthodontic treatment consisted of customized lingual appliances combined with a Class II fixed corrector.

Determination of Root Canal Cleanliness by Different Irrigation Methods and Morphometric Analysis of Apical Third.

AIM: The aim of this study was to determine the root canal area before and after the instrumentation 1 mm short of the apical foramen by clinical and cone beam computed tomography (CBCT) methods, and to evaluate the cleanliness of the apical region in mesiodistal flattened teeth by using optical microscopy. MATERIALS AND METHODS: Forty-two human single-canal mandibular incisors were instrumented using the Free Tip Preparation technique up to three, four or five instruments from the initial. Cone beam computed tomography scans were acquired of the samples before and after root canal preparation (RCP). Irrigation was performed by conventional or hydrodynamic means, using 2.5% sodium hypochlorite. The samples were prepared for observation under an optical microscope. Images were digitally obtained, analyzed and the results were submitted to statistical analysis (two-way ANOVA complemented by Bonferroni's post-test). RESULTS: There was no significant difference between the studied anatomical areas with both CBCT and clinical methods. There were no differences between irrigation methods. It was verified differences between instrumentation techniques. Instrumentation with four instruments from the initial instrument determined a significant increase in the contact area when compared to preparation with three instruments, but RCP with 5 instruments did not result in a better cleanliness. CONCLUSION: The analysis with CBCT was not capable to determine the precise shape of surgical apical area comparing to the clinical method. CLINICAL SIGNIFICANCE: Both the conventional and hydrodynamic irrigation techniques were not able to promote root canals debris-free. The instruments action in root canal walls was proportional to the number of instruments used from the initial apical instrument.

Using cone beam computed tomography images to diagnose multiple taurodontisms.

Taurodontism is a developmental anomaly that manifests as an alteration in a patient's internal morphology and is characterized by the lack of constriction at the level of the cementoenamel junction, which results in an apical extension of the pulp chamber that extends into the root area of a multiradicular tooth. This report presents a case of an otherwise healthy patient with 12 hypertaurodontic teeth, which were detected by using cone beam computed tomography (CBCT). It is essential to emphasize the importance of routine imaging examinations for diagnosing developmental dental anomalies such as taurodontism, as this condition is generally not found by routine oral examination, and is not necessarily restricted to syndromic patients. CBCT images contribute to the diagnosis of and treatment plan for taurodontism.

Spatial Position and Anatomical Characteristics Associated with Impacted Third Molars Using a Map-Reading Strategy on Cone-Beam Computed Tomography Scans: A Retrospective Analysis.

(1) Background: This study assessed the spatial position and anatomical features associated with impacted third molars through a map-reading strategy employing cone-beam computed tomography (CBCT). (2) Methods: The positioning of impacted third molars on CBCT was assessed using Winter's and Pell and Gregory's classifications. External root resorption in mandibular second molars was categorized according to Herman's classification. Additionally, the relationship between the mandibular third molar root apex and the mandibular canal was examined. Comparative statistical analysis was conducted using Fisher's exact test, with a significance level considered as 5%. (3) Results: The results indicated that, based on Winter's classification, 48.06 % of impacted teeth were positioned mesioangularly. Employing Pell and Gregory's classification, 43.22% of the impacted molars fell into positions B and C, with 54.2% classified as Class II. A notable 69.7% of teeth exhibited no contact between the root apex and the mandibular canal, and external root resorption in the distal aspect of the second molar was absent in 88.7% of cases. (4) Conclusions: Utilizing the map-reading strategy with CBCT scans to assess the anatomical positions and characteristics of impacted third molars enhances professional confidence and sets a standard for quality and safety in the surgical procedure for patients.

Rare case of gemination and fusion involving supernumerary teeth and second mandibular molar - Case report.

This article presents the rare case of a patient with gemination and fusion involving conical supernumerary teeth and the second mandibular molar, along with its treatment. The 13-year-old girl, without any associated syndromes and currently undergoing orthodontic treatment, was referred for evaluation due to the presence of a supernumerary tooth. Following a clinical examination and analysis of a panoramic radiograph, a cone beam computed tomography was requested for a more detailed assessment of the supernumerary tooth and its relationship with adjacent structures. The sagittal sections revealed the presence of two conical paramolar supernumerary teeth, which were geminated and fused to the mesial root of tooth 47. The suggested treatment was the surgical removal of the supernumerary teeth, which was successfully performed without complications and with good healing. After one-year post-procedure, the formation of periodontal ligament was verified at the site where the supernumerary teeth were extracted. The simultaneous occurrence of gemination of two supernumerary teeth and their fusion to a mandibular molar is extremely rare, and their surgical removal provided the patient with better plaque control in the region and contributed to the progress of orthodontic treatment. Key words:Gemination and fusion of supernumerary teeth and second mandibular molar.

Structural and torque changes in implant components of different diameters subjected to mechanical fatigue.

OBJECTIVES: To evaluate torque maintenance and structural damage in implant components of different diameters subjected to a fatigue challenge. METHODS: Thirty 10-mm-long, morse taper connection, titanium dental implants and their corresponding one-piece abutments were divided into three groups (n = 10) according to implant diameter: 4.3 mm (I4.3), 3.5 mm (I3.5), and 2.9 mm (I2.9). The implants were placed into a load-bearing fixture simulating bone tissue (modified G10), and the abutments were screwed into the implants to a final torque of 20 Ncm for the I4.3 and I3.5 and 15 Ncm for I2.9. The torque was secured by a digital torque meter. Cone-beam computed tomography (CBCT) scans were acquired and post-processed (e-Vol DX software) for all implant/abutment sets before and after subjecting them to fatigue in 37 °C distilled water (2 million cycles, constant load and frequency). The removal torque was measured using the same digital torque meter to calculate the difference in torque before and after fatigue. RESULTS: I2.9 showed substantial structural deformation compared with the other implant diameters (I3.5 and I4.3). However, the experimental groups did not show statistical differences for abutment loosening. SIGNIFICANCE: Implants smaller than 3.5 mm in diameter have a higher probability of structural deformation than standard-diameter implants. The association between tomographic scans and e-Vol DX software showed satisfactory consistency with the direct assessment using the digital torque meter, offering an additional tool to evaluate implant component loosening and structural deformations.

CBCT assessment of mandibular molar furcation following root canal retreatment using engine-driven instruments.

This study employed e-Vol DXS cone beam computed tomography (CBCT) software to assess dentin remnants in the furcation area of mesial canals in mandibular molars during root canal retreatment (RCR). Four groups (Reciproc®, ProTaper Next®, Race Evo®, Protaper Gold®) were subjected to RCR, and CBCT images were captured before (T1) and after (T2) treatment. Measurements of remaining dentin thickness at 1 mm and 3 mm below the furcation were scrutinized. Results revealed no significant differences in mean thicknesses of mesiobuccal (MB) and mesiolingual (ML) canals at 1 mm and 3 mm from the furcation pre-treatment (T1). Post-treatment (T2) showed analogous findings, with no significant differences in mean thicknesses. However, disparities were found between MB and ML canals at both distances, both before and after retreatment. In essence, the evaluated instruments exhibited safety in RCR, implying that they are appropriate for use in critical areas of mandibular molars without inducing excessive wear. This study underscores the reliability of these instruments in navigating danger zones during RCR, and contributes valuable insights for dental practitioners who handle complex root canal scenarios in mandibular molars.

Longevity of different abutments placed on narrow diameter implants: Assessment of structural damage and loosening.

OBJECTIVES: To evaluate structural damage and loosening of abutments placed on narrow diameter implants after cyclic fatigue. METHODS: Sixty Morse taper narrow diameter implants (Neodent, Brazil) received two types of abutments (1PA- one-piece abutment or 2PA- two-piece abutment), which were randomly divided into 3 fatigue experiments (n = 10). The implants were placed into a customized supporting holder and a software-assisted digital torque wrench secured the manufacturer recommended torque for each abutment. Cone beam computed tomography (CBCT) scans were acquired, before and after fatigue, and post-processed (software e-Vol DX) to assess damage and abutment displacement. The boundary fatigue method was adapted to use 2 × 106 cycles, 2 Hz of frequency and constant peak load of 80 N (first experiment) that varied according to the failure rate of previous specimens (second and third experiments). Failure was evaluated using CBCT scans and removal torque values. Data were used to estimate long-term torque degradation, probability of failure and Weibull modulus (software ALTA PRO9). RESULTS: All 2PA specimens became loosen independently of the applied fatigue load, and structural bending was observed in 14 abutments. Eight 1PA got loosen during the fatigue experiment. The Weibull analysis showed a lower modulus (m = 1.0; 0.7, 1.4) for 1PA than for 2PA (m = 2.6; 2, 3.4) resulting in longer predicted lifetimes and slower torque degradation for 1PA than for 2PA specimens. SIGNIFICANCE: 1PA showed greater long-term survival probability than 2PA. Predicting the lifetime and mechanical behavior of implant-abutment systems are useful information to clinicians during the decision-making process of oral rehabilitations.

A 3-year follow-up of implant placement in proximity to canalis sinuosus: Case study.

BACKGROUND: While the nasal fossa and nasopalatine canal are recognized limitations for immediate implants in esthetic areas, the canalis sinuosus (CS) and its branches have been largely overlooked. Neglecting this anatomy can lead to sensory issues, pain, and implant failure underscores the necessity of meticulous pre-surgical assessment and planning to mitigate risks and ensure implant success. This case highlights the need for comprehensive pre-surgical evaluation and precise planning to minimize these complications and ensure successful implant outcomes in this scenario. METHODS AND RESULTS: A 41-year-old woman with a history of root perforation and external root resorption was referred for dental implant placement. Following clinical evaluation and computed tomography, the presence of an accessory canal of the CS was identified. After meticulous planning to avoid implant contact with this structure, ridge preservation was performed. After 6 months, the implant was successfully placed following guided osteotomy. The case demonstrates clinical and radiographic stability after 36 months of follow-up. CONCLUSION: The correct diagnosis and planning, within a multidisciplinary team, can lead to successful implant placement in a challenging site with an anatomical variation. This study, to our knowledge, represents the first to propose an alternative treatment approach in the presence of CS in an esthetic region. KEY POINTS: Why is this case new information? This case emphasizes the importance of thorough pre-surgical evaluation to mitigate potential complications related to the CS. It is the first, to our knowledge, to propose an alternative treatment approach in the presence of this anatomical variation in an esthetic region. What are the keys to successful management in this case? Comprehensive pre-surgical evaluation, precise planning with detailed CBCT assessment to identify the CS, careful consideration of its anatomy during surgical intervention, knowledge of the limitations of tissue reconstructions, and precise clinical strategies to minimize associated complications. What are the primary limitations to success in this case? The need to position the implant with a safety margin from the CS led to implant positioning resulting in fenestration of the buccal bone plate, preventing its reconstruction due to the bone envelope's design, resulting in a discrepant gingival margin compared to the contralateral tooth, which did not allow for further crown lengthening due to a rather short root.

Incidental Findings Following Dental Implant Procedures in the Mandible: A New Post-Processing CBCT Software Analysis.

Background/Objectives: The aim of this study was to evaluate incidental findings in the mandible after the placement of dental implants using a new cone-beam computed tomography (CBCT) software. Methods: The initial sample consisted of 2872 CBCT scans of patients of both sexes. The parameters evaluated in this study were the location of the implants in the mandible, implant length, anatomical relationship of the implant with the mandibular canal, presence or absence of damage to the adjacent teeth, presence or absence of implant fractures, and presence or absence of bone support. Fisher's exact test was performed to compare the variables. The significance level was set at p = 0.05. Results: Out of 2872 CBCT scans, 214 images of patients with an average age of 44.5 years were included. The most frequent location of the implants was the posterior region (93.5%), with 54% of the implants having a length between 9 and 14 mm. It was found that 92% of the implants were positioned above the mandibular canal. Damage to adjacent teeth was observed, with no correlation with the implant positioning (p = 1.000). In 100% of cases of implants in the anterior region, there was bone support. Fracture was observed in 1.7% of implants with a length between 9 and 14 mm. Conclusions: The installation of implants in the mandible occurs more frequently in the posterior region, with a high presence of bone support and a low incidence of damage to adjacent teeth, anatomical structures, and fractures.

Solitary Median Maxillary Central Incisor in Hartsfield Syndrome: A Case Report.

Hartsfield syndrome is a rare and unique clinical combination of ectrodactyly and holoprosencephaly (HPE) with or without cleft lip and palate, as well as various additional characteristics. Although several genes responsible for HPE and ectrodactyly have been identified, the genetic origin of Hartsfield syndrome remains unknown, as there are few reports in the literature. The objective of this case report is to present dentofacial abnormalities in an 11-year-old boy with Hartsfield syndrome, who presented mental retardation, hearing loss, bilateral hand and foot ectrodactyly, HPE, and solitary median maxillary central incisor (SMMCI) besides 12 dental ageneses. How to cite this article: P Reis PM, Faber J, O Rosa JS, et al. Solitary Median Maxillary Central Incisor in Hartsfield Syndrome: A Case Report. Int J Clin Pediatr Dent 2023;16(1):147-152.

Method to determine the root canal spatial geometry using an algorithm of the e-Vol DX CBCT software.

This study evaluated a method to determine the spatial geometry of root canal preparation (RCP) using navigation dynamics and a specific algorithm from a new CBCT software (e-Vol DX). CBCT scans of 168 root canals of mandibular molars were acquired before and after RCP, using nickel-titanium (NiTi) instruments (ProTaper Next, BioRace, Reciproc Blue, and WaveOne Gold). The spatial geometry of the root canals and the operative risk of disproportional wear of dentinal walls after RCP were evaluated using a new CBCT software. A 3-point scoring system was used after the measuring of cementum/dentin thickness before and after RCP in all root thirds. The root thirds were distributed into three parts of similar sizes, and the scores were categorized at three levels: 1. mild risk (1/3), 2. moderate risk (2/3), 3. severe risk (3/3). These levels were proposed according to the risk of creating disproportionate shapes, thin walls, or perforations. The data were analyzed statistically by Fischer's exact test (α = 5%). There were no significant differences in operative risk among the NiTi engine-driven systems, for the distal or mesial walls of all the root canal thirds (p>0.05). The spatial geometry method to assess operative risk allows clinical planning for a predictable enlargement of the root canal in all root thirds. Based on using a map-reading strategy on root canals in CBCT scans, NiTi engine-driven instruments did not present an increased operative risk during RCPs.

A computational modeling method for root canal endoscopy using a specific CBCT filter: A new era in the metaverse of endodontics begins.

A contemporary technological revolution has started a new era in the metaverse of Endodontics, a world of virtual operational possibilities that use an exact replica of the natural structures of the maxillofacial complex. This study describes a modeling method for root canal endoscopy using modern cone-beam CT (CBCT) software in a series of clinical cases. The method consists in acquiring thin CBCT slices (0.10mm) in the coronal, sagittal, and axial planes. A specific 3D volume filter, the pulp cavity filter of the e-Vol DX CBCT software, was used to navigate anatomical root canal microstructures, and to scan them using root canal endoscopy. The pulp cavity filter should be set to synchronize CBCT scans from 2D mode - multiplanar reformations (MPR) - to 3D mode - volumetric reconstruction. This filter, when adopting the option of volumetric reconstruction, the developed algorithm leaves the dentin density in transparent mode so that the pulp cavity may be visualized. The algorithm applied performs the suppression (visual) of areas with dentin density. This ensures 3D visualization of the slices and the microanatomy of the root canal, as well as a dynamic navigation throughout the pulp cavity. This computational modeling method adds new resources to Endodontics, which may impact the predictability of root canal treatments positively. The virtual visualization of the internal anatomy of an exact replica of the canal ensures better communications, reliability, and clinical operationalization. Root canal endoscopy using this novel CBCT filter may be used for clinical applications together with innovative digital and virtual-reality resources that will be naturally incorporated into the principles of Endodontics.

Evaluation in the danger zone of mandibular molars after root canal preparation using novel CBCT software.

This study measured the thickness of cementum/dentin in the danger zone of the mandibular molars after root canal preparation using novel cone-beam computed tomography (CBCT) software. Eighty-four teeth were distributed into four groups: ProTaper Next, BioRace, Reciproc Blue, and WaveOne Gold. E-Vol DX® CBCT software was used to measure initial and final remaining cementum-dentin thicknesses after root canal preparation of the mesial root of mandibular molars at 1 and 3 mm from the furcation. The Kolmogorov-Smirnov test was used to test variable symmetry. The variables were described as mean and standard deviations, compared among the groups using analysis of variance (ANOVA), and within the groups using the Student t test. A generalized estimating equation model was used to compare the variation before and after root canal preparation. The level of significance was set at 5%. Differences between mean initial and final thicknesses of the mesiobuccal (MB) and mesiolingual (ML) canals were not statistically significant. The mean initial thickness was 3 mm (0.900 mm ± 0.191), considering that a mean lower than 1 mm (1.035 mm ± 0.184) indicates the danger zone. Although cementum/dentin is thinner at 3 mm from the furcation (0.715±0.186) after root canal preparation, the greatest amount of dentin removed was found at 1 mm (0.734 ± 0.191). The cementum-dentin remaining after preparation was thicker than 0.715 mm in root canals prepared using #35 (WaveOne Gold®) and #40 (ProTaper Next®, BioRace® and Reciproc Blue®) instruments. This confirms the safety of canal preparation in the danger zone using these systems.

Planned Apical Preparation Using Cone-Beam Computed Tomographic Measures: A Micro-Computed Tomographic Proof of Concept in Human Cadavers.

INTRODUCTION: This study assessed the amount of unprepared surface areas at the apical 4-mm segment of the root canal after a planned preparation based on cone-beam computed tomography (CBCT) measurements. METHODS: Eighteen posterior mandible segments were obtained from cadavers and scanned using CBCT and micro-computed tomographic (micro-CT) imaging. CBCT images were used to measure the largest initial canal diameter from 29 root canals of premolars at 1, 2, 3, and 4 mm short of the apical foramen. Each measurement was used to select a master apical instrument with size/taper that was 1 diameter larger to prepare the apical 4 mm of each particular root canal. A post-preparation micro-CT scan was obtained, and the unprepared canal areas were calculated. RESULTS: A very high amount of surface areas over the apical 4 mm of the root canal was included in the final preparation (mean >90%). The unprepared areas ranged from as low as 3.7% to a maximum of 14.6% (mean and median, 9.2% and 9.1%, respectively). CONCLUSIONS: The proposed planned apical root canal preparation resulted in optimized root canal shaping with a substantial amount of prepared surface areas. The protocol used also resulted in a conservative canal enlargement using final instruments that were 1 size larger than the initial largest canal diameter.

Frequency and Risk Factors of Maxillary Sinusitis of Endodontic Origin Evaluated by a Dynamic Navigation and a New Filter of Cone-Beam Computed Tomography.

INTRODUCTION: The aim of this study was to determine the frequency and risk factors of maxillary sinusitis of endodontic origin (MSEO) on posterior maxillary teeth evaluated using dynamic navigation and a novel filter of cone-beam computed tomographic (CBCT) imaging. METHODS: CBCT scans of 453 patients (814 teeth) were selected. Data were divided into 4 groups: (1) root canal treatment (RCT), (2) relation of the root apex to the maxillary sinus, (3) apical periodontitis (AP), and (4) maxillary sinus inflammation (no inflammation, periapical osteoperiostitis, periapical mucositis, partial obstruction, or total obstruction). Frequency distribution and cross-tabulation were used for data analysis. The association of maxillary sinus abnormalities with other variables was analyzed using the chi-square test. The significance level was set at 5%, and the association between dependent and independent variables was analyzed using robust Poisson regression models. RESULTS: MSEO was found in 65.6% of the cases, and the highest frequency rates were in the periapical mucositis (44%) and partial obstruction (15.8%) groups. The rates of risk factors were highest in the cases of RCT (54.9%), AP (34.3%), and the root apex in contact with the maxillary sinus (53.8%). The most frequent sex and age group were female (55.8%) and 41-50 years (30.5%). CONCLUSIONS: The frequency of MSEO was high and positively associated with RCT, AP, and the root apex's position in contact with the floor of the maxillary sinus. The maxillary sinus filter of the CBCT software provides a clear image of maxillary sinus abnormalities.

A Critical Review of the Differential Diagnosis of Root Fracture Line in CBCT scans.

The objective of this critical review of literature is to discuss relevant clinical factors associated with root fractures (RF) visualized by using a new CBCT software. RF constitutes a common occurrence and a challenge in clinical practice, in which the diagnosis becomes essential for the definition of rapid and precise decision-making. The characterization of RF may involve different aspects, such as orientation of the fracture line (horizontal, vertical, oblique), root position of the fracture (cervical, middle, apical third), fracture's coronal-radicular position (coronary, coronal-radicular, radicular), continuity of the fracture (crack, incomplete fracture, complete), bone extension of the fracture (supraosseous, bone level, infraosseous fracture). Imaging examinations have been routinely used to aid in the RF diagnosis. Even with high-resolution cone-beam computed tomography (CBCT) scans, many doubts often remain about the diagnostic outcome. Many interferences in the analysis of image quality to determine the diagnosis are identified, such as the sharpness, the noise, light and dark artifacts, among others. The professional's knowledge is essential for identifying the different patterns of fracture lines and their repercussions on adjacent bone tissues, as well as for the analysis of artifacts that may hide or show similarities to fracture lines. Fractures lines and root fractures that may be associated with phantom conditions that mimic fractures should be carefully analyzed. CBCT is the exam indicated to identify a root fracture. It is also added to the success of the diagnosis that the professional has scientific knowledge, training and mastery of advanced CBCT software.

Preserving the Neurovascular Bundle in Targeted Endodontic Microsurgery: A Case Series.

Endodontic microsurgery encompasses the use of microscopy, specialized instruments, and advanced imaging with cone-beam computed tomographic (CBCT) imaging. This treatment modality results in high clinical success rates and facilitates the enucleation of osteolytic lesions, the resection of apical root canal complexities harboring persistent bacterial biofilms, and the evaluation of possible root defects and fractures. However, there is the risk of injury to important anatomic structures, particularly when treating posterior teeth. Neurovascular bundles are among these structures at risk for injury. Fortunately, high-resolution CBCT scans can be used to detect these structures that are known to have a high anatomic variability. In addition, CBCT information can be combined with high-resolution intraoral scans to plan, design, and fabricate surgical guides to be used in a targeted endodontic microsurgery (TEMS) approach. We report 3 cases with previous endodontic treatment having persistent apical periodontitis that were treated with TEMS to avoid damage to the neurovascular bundles at risk of injury. In the first case, the palatal root of tooth #14 was adjacent to the greater palatine artery. In the second case, the mental nerve exited through 2 separate foramina close to the predictive osteotomy site for the mesial root of tooth #19. In the third case, the posterior superior alveolar artery was in close proximity to the mesiobuccal root of tooth #14. Collectively, these cases illustrate the diagnostic value of CBCT imaging for detecting neurovascular bundles and the use of TEMS to mitigate the risk of injury to these important structures. Thus, the combination of CBCT imaging and TEMS can potentially minimize the risk of intraoperative complications and postoperative sequelae while increasing the predictability of endodontic microsurgeries in complex cases.

Method to Identify Accessory Root Canals using a New CBCT Software.

This study describes a methodology to identify accessory root canals using the e-Vol DX software in CBCT scans. Accessory root canals are strategic shelters for microorganisms present in root canal infections. The identification of these small canals in periapical radiographic exams has limitations, besides being markedly limited accessibility to the action of endodontic instruments and to the antimicrobial agents. A significant number of accessory canals have sufficient diameters to be visible on cone-beam computed tomography (CBCT) images of high spatial resolution. Therefore, it may go unnoticed or even confused when there is no specific training for this type of diagnosis. The methodology consists in establishing thin slices (0.1mm or smaller) obtained from coronal, sagittal and axial slices. The method consists of the following steps: during navigation along the long axis of a root canal when finding a possible hypodense line of main root canal in a tomographic section (axial, sagittal or coronal), the navigation software lines of the multiplanar reconstruction (MPR) must be adjusted so that they are parallel and perpendicular to the hypodense line (parallax correction). Then, after judiciously adjusted, the accessory canal image will invariably appear as a line on one of the MPR tomographic slices, another line on another slice, and a dot on the third slice. The three sections of the MPR present images with the "line-line-dot" sequence. In this way, it is possible to identify an accessory root canal and also visualize it in volumetric reconstruction in a specific filter. The application of this method is easy to employed and may benefit the diagnosis when you want to visualize accessory root canals and distinguish it from root fracture line.