Healing and long-term prognosis of root-fractured permanent teeth: a retrospective longitudinal study.

AIM: The purpose of the present study was to evaluate permanent teeth with post-traumatic transversal root fractures, for their initial healing modality, the effect of candidate predictors and their long-term prognosis. METHODOLOGY: A retrospective longitudinal clinical study was conducted to evaluate records from patients bearing transversal root fractures in permanent teeth in order to radiographically assess short-term healing and non-healing events in the fracture line, their prognostic factors and their relationship with long term outcomes. The inter-fragmentary tissues were classified as healing: hard tissue (HT), connective tissue (CT) or connective tissue and bone (CT + B) and non-healing: interposition of granulation tissue (GT). A competing risk survival analysis was conducted to estimate the hazards of healing and non-healing events in the short-term and the effect of demographic, clinical, and treatment variables was assessed using the subdistribution regression model (Fine & Gray). RESULTS: Radiographic findings showed 61.4% of healing in the short-term being strongly influenced by the presence and type of concomitant injuries to the coronal fragment. Teeth with concomitant crown fractures (sHR 24.38, 95% CI [3.16-188.3], p = 0.0022), luxations with dislocations (sHR 10.58, 95% CI [1.37-81.9], p = 0.0240) and subluxations (HR 9.66, 95% CI [1.14-81.7], p = 0.0370) were more likely to present non-healing of root fractures in the short-term. The healing rate in the long-term was of 75.9%, most of them with interposition of bone and connective tissue. Kappa statistics demonstrated an overall agreement of 67.1% between short and long-term healing patterns, in special HT and CT + Bone modalities. CONCLUSION: Healing at the fracture site was the most frequent outcome, both in the short-term and in the long-term. Short-term healing modality was strongly influenced by the presence and type of concomitant injuries to the crown fragment, being the worst prognosis observed in root-fractured teeth with concomitant crown fractures, followed by concomitant luxations with dislocation. CLINICAL RELEVANCE: Post-traumatic transversal root fractures have a positive prognosis supporting therefore, a more conservative approach for these teeth before considering more radical treatments.

Radiographic Criteria for Differential Diagnosis Between Vertical Root Fracture and Apical Periodontitis in Single-Rooted Endodontically Treated Premolars Using Cone-Beam Computed Tomography.

INTRODUCTION: This study explores the differences between the patterns of bone defects associated with vertical root fracture (VRF) and apical periodontitis (AP) in single-rooted endodontically treated premolars (SRETPs) based on cone-beam computed tomography (CBCT) data. METHODS: Eighty-four SRETPs were extracted and categorized into the VRF and AP groups. On preoperative CBCT images, the location of bone defects according to the root thirds in buccolingual and mesiodistal directions across the study groups were compared. RESULTS: The majority of bone defects in the VRF group were longitudinal and combined, involving more than one root thirds in buccolingual and mesiodistal directions simultaneously. A uniform approach to comparing bone defects using the sites of periradicular area with bone loss as a comparison unit was developed. In the VRF group, bone loss sites in the middle and coronal thirds were detected more often and were located mainly buccolingually compared with the AP group (P < .001). CONCLUSION: Bone defects in the middle or middle and coronal root thirds in the buccolingual direction may be potential radiographic signs useful in differentiating between VRF and AP in SRETPs. The introduction of the uniform approach to assessment of bone loss patterns will give practitioners a single simple tool and improve the quality of endodontic treatment.

7.5- to 11.5-Year Follow-up of the Fracture Removal Treatment for Propagated Crown Fractures.

A definitive method to predictably treat propagated longitudinal fractures remains elusive. A proof-of-concept case report series documenting nonsurgical removal of propagated longitudinal fractures has shown up to 5 years of clinical and radiographic success. This installment of the case report series further documents these teeth with 7.5-year to 11.5-year recall evaluations. Three previously reported cases of fracture removal were followed at 11.5 years (1 case), 9.75 years (1 case), and 7.5 years (1 case) after treatment to determine the long-term clinical and radiographic success of nonsurgical fracture removal. This case report series has demonstrated 10-year success (clinically and radiographically) for the treatment of progressive longitudinal fractures. Propagated fractures can be nonsurgically removed and the iatrogenic defect repaired with long-term success providing a foundation for treatment and further investigation.

Influence of an adjacent zirconium implant, tube current, and metal artifact reduction algorithm on horizontal root fracture diagnosis in cone beam computed tomography.

OBJECTIVE: We evaluated the influence of an adjacent zirconium implant, tube current (mA), and a metal artifact reduction algorithm (MARA) on horizontal root fracture (HRF) diagnosis in cone beam computed tomography (CBCT). STUDY DESIGN: Nineteen teeth (9 with HRF, 10 without) were individually placed in a human maxilla. Scan volumes were acquired without and with a zirconium implant adjacent to the tooth at settings of 4, 8, and 10 mA, with MARA disabled and enabled, using a 5×5 cm field of view, 0.085-mm voxel size, and 90 kV. Four maxillofacial radiologists individually assessed the scans. Diagnostic metrics were compared by multiway analysis of variance (α=5%). Inter- and intraexaminer agreements for HRF diagnosis were evaluated with the weighted kappa test. RESULTS: Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were significantly lower in the presence of the implant (P≤.005). AUC values were higher in scans obtained with 8 and 10 mA compared with 4 mA (P=0.010), but 10 mA without MARA was better with the implant present. MARA did not significantly influence outcomes (P≥0.240). Inter- and intraexaminer agreements ranged from moderate to almost perfect. CONCLUSIONS: The presence of the zirconium implant impairs HRF detection. Settings of 8 or 10 mA improve HRF detection regardless MARA condition without the implant. With an adjacent implant, 10 mA without MARA is recommended to improve diagnostic performance.

Fragment Reattachment: A 4-Year Case Report of Uncomplicated Dental Fractures.

Two fractured maxillary central incisors were restored via the crown fragment reattachment technique with adhesive systems and composite resin material. A long-term successful outcome was achieved after 4 years of follow-up. The patient presented with fractured maxillary central incisors, and a comprehensive intraoral and radiographic examination revealed that both teeth had extended crown fractures with no pulpal exposure (Class II, Ellis and Davey). The tooth fragments were thoroughly cleaned and inspected before being repositioned. Both fragments were in excellent condition with almost no pieces missing. Therefore, the proposed treatment was fragment reattachment. After verifying the repositioning and adaptation of the fractured fragments, a flowable composite was used to perform the reattachment procedure under rubber dam isolation. With modern dental adhesives, the reattachment of tooth fragments in good condition is considered a more conservative option for restoring tooth morphology, esthetics, and function. Although one tooth showed signs of irreversible pulpitis and required root canal treatment 2 weeks after the restoration, the clinical and radiographic evaluations at the 4-year follow-up visits confirmed the success of the restorative treatment. The restorations showed good functional and esthetic outcomes after 4 years of follow-up.

Diagnostic efficacy of cone-beam computed tomography for detection of vertical root fractures in endodontically treated teeth: a systematic review.

BACKGROUND: Vertical root fractures (VRFs) sometimes occur in endodontically treated teeth. They have a difficult diagnosis and a dismal result. The objective of this review was to evaluate the diagnostic performance of cone-beam computed tomography (CBCT) for detecting VRFs in teeth that had undergone endodontic treatment. METHODS: Literature was reviewed from Web of Science, PubMed, Cochrane Review, SCOPUS, and Embase databases between 2000 and 2022. The searched keywords included "endodontically treated teeth," "cone-beam computed tomography," "CBCT," "tooth fracture," "vertical root fracture," "VRF," "accuracy," "sensitivity," and "specificity." Only articles in the English language were included. The final analysis included 20 papers that satisfied the eligibility requirements. RESULTS: The overall mean ± SD values (%) for the diagnostic sensitivity and specificity of CBCT for detection of VRFs in endodontically treated teeth in the presence of root-filling materials without an intracanal post were 71.50 ± 22.19 and 75.64 ± 19.41, respectively. The overall mean (SD) value (%) for the sensitivity of CBCT for the detection of VRFs in the presence of root-filling materials and intracanal posts was 72.76 (18.73), while the mean (SD) specificity was 75.44 (18.26). The accuracy of CBCT (mean ± SD) was 78.47 ± 17.19% and 74.02 ± 10.64%, respectively, for teeth without intracanal posts and those with posts. CONCLUSIONS: Further clinical research is needed to validate the optimum efficiency of CBCT as a diagnostic technique for detecting VRFs in teeth that have had endodontic treatment, given the low sensitivity, significant heterogeneity of studies, and lack of in-vivo studies on the subject.

Influence of voxel size and filter type on detecting vertical root fracture using cone-beam computed tomography.

Vertical root fractures (VRFs) can start at any level of the root and progress longitudinally to the coronal attachment. This study aimed to investigate the effects of different exposure parameters used when obtaining CBCT scans in detecting simulated VRFs. Hence, 80 intact human mandibular single-rooted pre-molar teeth without root fractures were included in the study. No statistically significant difference was found between the filters in terms of VRF detection in the group with the roots with only root canal filling (Groups 1 and 5); however, 100 voxels were found to be more successful in terms of VRF detection than other voxel sizes. Results of this study suggest that using lower voxel sizes leads to an accurate diagnosis of vertical root fracture, in addition, our results revealed that using AR filters did not improve the diagnostic accuracy in detecting VRFs.

[Effect of various intracanal materials on the diagnostic accuracy of cone-beam computed tomography in vertical root fractures].

OBJECTIVE: To study the effect of various intracanal materials on the accuracy of oral maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of vertical root fracture (VRF). METHODS: A total of twenty-four structurally intact single root canal dried and isolated teeth extracted for orthodontic treatment or periodontal disease were collected. The teeth were decrowned along the cemento-enamel junction (CEJ) and then used as samples for the study after conventional root canal preparation and post preparation. The 24 samples were divided into two groups with 12 samples in each group. Group A was the control group (no VRF group). According to intracanal materials, they were divided into five subgroups: blank group, fiber post group, gutta-percha point group, titanium post group and gold-palladium post group. Group B was the experimental group (VRF group), and subgroups were grouped as above. The VRF model was prepared by a unified method in the VRF group: the root was completely fractured in the buccolingual direction with a custom root canal nail and then cemented and reset. The control group was not subjected to the simulation of VRF. Titanium post and gold-palladium post were made according to the individuality of the root canal preparation, and the tightness of the post to the root canal wall was confirmed by X-ray radiograph. Then all the samples were scanned by CBCT in the isolate swine mandibular alveolar sockets. The diagnostic accuracy was statistically analyzed via blind interpretation by experienced endodontic specialists and oral and maxillofacial medical imaging specialists. RESULTS: The accuracy of the diagnosis of VRF in the blank group, fiber post group, gutta-percha point group, titanium post group, and gold-palladium post group in CBCT was 95.83%, 91.67%, 87.50%, 79.17%, and 45.83%, respectively. Compared with the blank group, the differences were not statistically significant in the fiber post group (P>0.999), the gutta-percha point group (P=0.500) and the titanium post group (P=0.125). The lowest diagnostic accuracy of VRF was found in the gold-palladium post group, and the difference was statistically significant compared with all other groups (P < 0.001). CONCLUSION: Various intracanal materials have different degrees of influence on the diagnostic accuracy of VRF diagnosis in CBCT. The influence of fiber post, gutta-percha point and titanium post was small, while the influence of gold-palladium post was significant.

Management of Crown-root Fracture with 180-degree Rotation Replantation: a Report of 2 Cases.

Intentional replantation involves a combination of periodontics, endodontics, prosthodontics and oral surgery. Crown-root fracture management is still complicated nowadays. A fracture line extending longitudinally to the subgingival area and intruding bioogical width could affect infection control, gingival health and crown restoration. In the present study, we present two cases. Case 1 involved a 23-year-old man who presented at our hospital with crown-root fracture of the maxillary left central incisor. A radiographic image of the tooth revealed a fracture line under the alveolar crest. The fractured tooth was treated with intentional replantation with 180-degree rotation, root canal treatment and veneer restoration. The patient was followed up for 60 months. The replanted tooth functioned well, and no symptoms of resorption or ankylosis were observed by radiographic examination. Case 2 involved a 20-year-old woman who was referred to our hospital for crown-root fracture of her maxillary teeth. A radiographic examination revealed complicated crown-root fracture of the maxillary right lateral incisor and both maxillary central incisors. The central incisors were treated with intentional replantation with 180-degree rotation. At the 48-month follow-up, the fractured teeth were found to have regained normal function based on clinical and radiographic examination. Limited case reports are available on a long-term follow-up of intentional replantation with 180-degree rotation. These two cases, particularly case 2, presented optimal healing after 4 years with unideal crown-root ratios. This case report suggests that this old method of preserving teeth with crown-root fractures can be used as a last resort to save teeth owing to its timesaving and microinvasive procedure.

Sensitivity and Specificity of MRI versus CBCT to Detect Vertical Root Fractures Using MicroCT as a Reference Standard.

INTRODUCTION: Vertical root fracture (VRF) in root-canal-treated teeth frequently results in tooth loss, partly because VRFs are difficult to diagnose and when detected the fracture is often beyond the point of preservation with surgical intervention. Nonionizing magnetic resonance imaging (MRI) has demonstrated the ability to detect small VRFs, but it is unknown how its diagnostic capabilities compare with the current imaging standard for VRF detection, cone-beam computed tomography (CBCT). This investigation aimed to compare the sensitivity and specificity between MRI and CBCT for detecting VRF, using micro-computed tomography (microCT) as a reference. METHODS: A total of 120 extracted human tooth roots were root canal treated using common techniques, and VRFs were mechanically induced in a proportion. Samples were imaged using MRI, CBCT, and microCT. Axial MRI and CBCT images were examined by 3 board-certified endodontists, who evaluated VRF status (yes/no) and gave a confidence assessment for that decision, from which a receiver operating characteristic curve was generated. Intra- and inter-rater reliability were calculated, sensitivity and specificity, and area under the curve. RESULTS: Intra-rater reliability was 0.29-0.48 for MRI and 0.30-0.44 for CBCT. Inter-rater reliability for MRI was 0.37 and for CBCT 0.49. Sensitivity was 0.66 (95% confidence interval [CI], 0.53-0.78) and 0.58 (95% CI, 0.45-0.70), and specificity 0.72 (95% CI, 0.58-0.83) and 0.87 (95% CI, 0.75-0.95) for MRI and CBCT, respectively. Area under the curve was 0.74 (95% CI, 0.65-0.83) for MRI and 0.75 (95% CI, 0.66-0.84) for CBCT. CONCLUSIONS: There was no significant difference in sensitivity or specificity between MRI and CBCT in detecting VRF, despite the early-stage development of MRI.

Managing a Deep Subgingival Cusp Fracture: Case Reports.

Cuspal fractures are relatively common. Fortunately for esthetics, when a cuspal fracture occurs in a maxillary premolar, it most commonly involves the palatal cusp. Fractures with a favorable prognosis may be approached with a minimally invasive treatment to successfully retain the natural tooth. This report describes 3 cases of "cuspidization" to treat maxillary premolars with cuspal fractures. After identifying a palatal cusp fracture, the fractured segment was removed, resulting in a tooth that closely resembles a cuspid. Depending on the extent and location of the fracture, root canal treatment was indicated. Subsequently, conservative restorations sealed the access and covered exposed dentin. Full coverage restorations were neither required nor indicated. The resulting treatment provided practical and functional treatment with a good esthetic outcome. When indicated, the described cuspidization technique can conservatively manage patients with subgingival cuspal fractures. The procedure is minimally invasive and cost-effective and can be done conveniently in routine practice.

Detection of vertical root fractures by cone-beam computed tomography based on deep learning.

OBJECTIVES: This study aims to evaluate the performance of ResNet models in the detection of in vitro and in vivo vertical root fractures (VRF) in Cone-beam Computed Tomography (CBCT) images. METHODS: A CBCT image dataset consisting of 28 teeth (14 intact and 14 teeth with VRF, 1641 slices) from 14 patients, and another dataset containing 60 teeth (30 intact and 30 teeth with VRF, 3665 slices) from an in vitro model were used for the establishment of VRFconvolutional neural network (CNN) models. The most popular CNN architecture ResNet with different layers was fine-tuned for the detection of VRF. Sensitivity, specificity, accuracy, PPV (positive predictive value), NPV (negative predictive value), and AUC (the area under the receiver operating characteristic curve) of the VRF slices classified by the CNN in the test set were compared. Two oral and maxillofacial radiologists independently reviewed all the CBCT images of the test set, and intraclass correlation coefficients (ICCs) were calculated to assess the interobserver agreement for the oral maxillofacial radiologists. RESULTS: The AUC of the models on the patient data were: 0.827(ResNet-18), 0.929(ResNet-50), and 0.882(ResNet-101). The AUC of the models on the mixed data get improved as:0.927(ResNet-18), 0.936(ResNet-50), and 0.893(ResNet-101). The maximum AUC were: 0.929 (0.908-0.950, 95% CI) and 0.936 (0.924-0.948, 95% CI) for the patient data and mixed data from ResNet-50, which is comparable to the AUC (0.937 and 0.950) for patient data and (0.915 and 0.935) for the mixed data obtained from the two oral and maxillofacial radiologists, respectively. CONCLUSIONS: Deep-learning models showed high accuracy in the detection of VRF using CBCT images. The data obtained from the in vitro VRF model increases the data scale, which is beneficial to the training of deep-learning models.

Influence of the technical parameters of CBCT image acquisition on vertical root fracture diagnosis: a systematic review and meta-analysis.

OBJECTIVES: To evaluate the influence of image acquisition parameters (voxel, FOV, kVp, mA) on the accuracy of cone-beam computed tomography (CBCT) in detecting vertical root fracture (VRF). MATERIAL AND METHODS: Searches were performed in 6 main databases and the gray literature, without restrictions of language or date. Observational clinical studies (OCS) and in vitro-extracted teeth (IV) studies were considered eligible for inclusion when investigating the accuracy (sensitivity, specificity) of CBCT in detecting VRF in human teeth. The risk of bias was assessed using QUADAS-2, and a meta-analysis was performed using Review Manager v5.4 software and Jamovi software v1.6. RESULTS: A total of 60 out of 132 articles was included after fulfilling the eligibility criteria. Of these, 54 were IV studies while 6 were OCS. In the IV studies, it was seen that smaller FOV sizes tended to present higher accuracy values. The meta-analysis of the 6 OCS showed that the overall sensitivity and specificity values for 0.08 mm and 0.1 mm voxels were greater (0.84 and 0.79, respectively) than the sensitivity and specificity values for 0.125 mm and 0.2 mm voxels (0.70 and 0.55, respectively). CONCLUSIONS: Despite the uncertain risk of bias found for the IV and OCS studies, smaller voxel and FOV sizes seem to provide more accurate VRF detection values when using CBCT. CLINICAL RELEVANCE: This information is crucial for supporting the clinician when prescribing CBCT in cases of a clinical suspicion of VRF, and contributes to the personalization of the CBCT prescription, thereby ensuring greater accuracy in the VRF diagnosis. Registration This protocol was registered at the PROSPERO database (International Prospective Register of Systematic Review) under registration number CRD42020210118.

Development of a predictive model for identifying previously undetected vertical root fractures.

This study aimed to develop a predictive model to screen for undetected vertical root fractures (VRFs) in root canal treated teeth. We included 95 root canal treated teeth with suspected VRFs; 77 for training and 18 for validation. Following clinical and cone-beam CT parameters were recorded: sex, tooth type, coronal restoration, time interval from completion of endodontic treatment to definitive diagnosis (TI), type of bone loss (BL), apical extent of root filling (AR) and the ratio of root filling diameter to the actual diameter in the coronal (1/3TA) and middle (2/3TA) root thirds. A predictive model p = 1/(1 - e-x ) was generated, where x = -7.433 + 1.977BL + 1.479 (2/3TA) + 1.102 AR; the sensitivity and specificity were 0.852 and 0.875 for training and 0.917 and 0.833 for validation. VRF teeth were more likely to have vertical bone loss and overfilled root canals. This model had a high diagnostic efficacy for VRFs.

Effect of different intracanal posts and exposure parameters on detection of vertical root fractures by cone-beam computed tomography.

This study evaluated the effect of different amperage values and voxel sizes of two CBCT scanners on VRF detection in the presence of different intracanal posts. After post-space preparation, VRFs were induced in half of the samples of 20 maxillary premolars. Five different intracanal posts were passively placed in each root canal. Samples were scanned using CS 9300 and Cranex3D with two different voxel sizes and amperage setting in each unit. The diagnostic sensitivity, specificity and accuracy were compared using the Mann-Whitney and Kruskal-Wallis tests (α = 0.05). Changes in amperage and voxel size did not affect the detection of VRFs (p ⟩ 0.05). The VRF detection accuracy was the highest in fibreglass and the lowest in nickel-chromium group. Changes in amperage and voxel size within assessed values do not seem to influence the detection of VRF whereas different intracanal post-materials have significant effect on VRF detection.

Effect of various intracanal materials on the diagnostic accuracy of cone-beam computed tomography in vertical root fractures / 北京大学学报(医学版)

OBJECTIVE@#To study the effect of various intracanal materials on the accuracy of oral maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of vertical root fracture (VRF).@*METHODS@#A total of twenty-four structurally intact single root canal dried and isolated teeth extracted for orthodontic treatment or periodontal disease were collected. The teeth were decrowned along the cemento-enamel junction (CEJ) and then used as samples for the study after conventional root canal preparation and post preparation. The 24 samples were divided into two groups with 12 samples in each group. Group A was the control group (no VRF group). According to intracanal materials, they were divided into five subgroups: blank group, fiber post group, gutta-percha point group, titanium post group and gold-palladium post group. Group B was the experimental group (VRF group), and subgroups were grouped as above. The VRF model was prepared by a unified method in the VRF group: the root was completely fractured in the buccolingual direction with a custom root canal nail and then cemented and reset. The control group was not subjected to the simulation of VRF. Titanium post and gold-palladium post were made according to the individuality of the root canal preparation, and the tightness of the post to the root canal wall was confirmed by X-ray radiograph. Then all the samples were scanned by CBCT in the isolate swine mandibular alveolar sockets. The diagnostic accuracy was statistically analyzed via blind interpretation by experienced endodontic specialists and oral and maxillofacial medical imaging specialists.@*RESULTS@#The accuracy of the diagnosis of VRF in the blank group, fiber post group, gutta-percha point group, titanium post group, and gold-palladium post group in CBCT was 95.83%, 91.67%, 87.50%, 79.17%, and 45.83%, respectively. Compared with the blank group, the differences were not statistically significant in the fiber post group (P>0.999), the gutta-percha point group (P=0.500) and the titanium post group (P=0.125). The lowest diagnostic accuracy of VRF was found in the gold-palladium post group, and the difference was statistically significant compared with all other groups (P < 0.001).@*CONCLUSION@#Various intracanal materials have different degrees of influence on the diagnostic accuracy of VRF diagnosis in CBCT. The influence of fiber post, gutta-percha point and titanium post was small, while the influence of gold-palladium post was significant.

Impact of Fracture Line Width on Radiographic Diagnosis of Vertical Root Fractures: Analysis of the Generalised Estimating Equation Model.

OBJECTIVE: To undertake a joint analysis of the influence of fracture width, dental thickness and distance of the fracture from the cortical bone on the radiographic diagnosis of vertical root fractures. METHODS: Thirty-six uniradicular bovine teeth were endodontically treated and distributed into three groups according to the remaining root dentine thickness: 1.2 mm, 1.5 mm and 1.8 mm. Each group comprised 12 teeth, six with vertical root fracture and six without. Scanning electron microscopy (SEM) images of the fractured tooth groups were obtained and the fracture lines were measured. All specimens were inserted into bone defects created in bovine ribs, at different distances from the external cortical bone. Digital periapical radiographs were randomly evaluated by three blinded examiners (presence or absence of fractures). RESULTS: The specificity for periapical radiography was found to be 89% and the accuracy rate was 57.4%. The mixed-model regression using the generalised estimating equation (GEE) model showed that the width of the fracture line and the thickness of the dental remnant play an important role in radiographic detection of vertical root fractures. There is a lower chance of correct diagnosis with fracture line widths < 0.2 mm (odds ratio [OR] 0.294, 95% confidence interval [CI] 0.103 to 0.836; P = 0.022) and tooth thicknesses < 1.2 mm (OR 0.342, 95% CI 0.157 to 0.747; P = 0.007). CONCLUSION: Fracture line widths < 0.2 mm and smaller root thicknesses lead to a less accurate diagnosis of vertical root fractures on periapical radiographs.

Minimal Detectable Width of Tooth Fractures Using Magnetic Resonance Imaging and Method to Measure.

INTRODUCTION: Vertical root fracture (VRF) in root canal-treated (RCT) teeth is a common cause of pain, bone resorption, and tooth loss. VRF is also difficult to diagnose and measure. Magnetic resonance imaging (MRI) has the potential to identify VRF due to beneficial partial volume averaging, without using ionizing radiation. This investigation aimed to describe the narrowest VRFs detectable based on MRI, using micro-computed tomography (microCT) as the reference standard and proposes a method using profile integrals to measure the widths of small VRFs. METHODS: VRFs were induced in 62 RCT tooth root samples. All samples were imaged in a phantom using MRI and reference imaging was obtained using microCT. The stacks of 3-dimensional axial MRIs were assessed by 3 board-certified endodontists. Evaluators determined the most coronal slice within the stack that was discernible as the extent of the VRF. This slice was measured on correlated microCT sections to determine the minimum VRF width (µm) detectable using a profile integral-based method to measure small fractures and negate the effects of the point spread function. RESULTS: Using profile integrals to measure VRF width was repeatable and resulted in estimates that were on average 1 µm smaller than known reference widths. Adjusted median VRF width detected using MRI was 45 µm (first quartile: 26 µm, third quartile: 64 µm). CONCLUSION: Using profile integrals is a valid way to estimate small VRF width. The MRI approach demonstrated ability to repeatedly detect VRFs as small as 26 µm.

Diagnosis of in vivo vertical root fracture using deep learning on cone-beam CT images.

OBJECTIVES: Evaluating the diagnostic efficiency of deep learning models to diagnose vertical root fracture in vivo on cone-beam CT (CBCT) images. MATERIALS AND METHODS: The CBCT images of 276 teeth (138 VRF teeth and 138 non-VRF teeth) were enrolled and analyzed retrospectively. The diagnostic results of these teeth were confirmed by two chief radiologists. There were two experimental groups: auto-selection group and manual selection group. A total of 552 regions of interest of teeth were cropped in manual selection group and 1118 regions of interest of teeth were cropped in auto-selection group. Three deep learning networks (ResNet50, VGG19 and DenseNet169) were used for diagnosis (3:1 for training and testing). The diagnostic efficiencies (accuracy, sensitivity, specificity, and area under the curve (AUC)) of three networks were calculated in two experiment groups. Meanwhile, 552 teeth images in manual selection group were diagnosed by a radiologist. The diagnostic efficiencies of the three deep learning network models in two experiment groups and the radiologist were calculated. RESULTS: In manual selection group, ResNet50 presented highest accuracy and sensitivity for diagnosing VRF teeth. The accuracy, sensitivity, specificity and AUC was 97.8%, 97.0%, 98.5%, and 0.99, the radiologist presented accuracy, sensitivity, and specificity as 95.3%, 96.4 and 94.2%. In auto-selection group, ResNet50 presented highest accuracy and sensitivity for diagnosing VRF teeth, the accuracy, sensitivity, specificity and AUC was 91.4%, 92.1%, 90.7% and 0.96. CONCLUSION: In manual selection group, ResNet50 presented higher diagnostic efficiency in diagnosis of in vivo VRF teeth than VGG19, DensenNet169 and radiologist with 2 years of experience. In auto-selection group, Resnet50 also presented higher diagnostic efficiency in diagnosis of in vivo VRF teeth than VGG19 and DensenNet169. This makes it a promising auxiliary diagnostic technique to screen for VRF teeth.

Establishment of Narrow Root Fracture Models Using Modified Temperature Cycling Method and Diagnosis Using Different Cone-Beam CT Units.

Aim: Using a modified thermal cycling method to establish narrow root fracture models and evaluate the diagnosis efficiency of them using four different cone-beam CT (CBCT) units. Methodology. Fifty-six intact teeth were selected, and the crowns of the teeth were embedded using general purpose acrylic resin. 50 root fracture models were established by soaking these teeth in liquid nitrogen and hot water cyclically; 6 teeth were used as the negative control. All the 56 teeth were scanned with the smallest voxel size of four different CBCT units (NewTom VGi, Planmeca Promax 3D Max, Kavo 3D eXam, and Soredex Scanora3D). 10 teeth were randomly selected, and the roots were sliced using slow-speed saw to obtain horizontal root sections. Scanning electron microscope (SEM) was used to measure the width of the fracture lines (FLs). The CBCT images were evaluated for the presence or absence of fracture lines. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the diagnosis of FLs using the four CBCT units. Results: Fifty narrow root fracture models were successfully established, and 25 root sections with 45 FLs were acquired. The width of FLs was from 3.43 µm to 143 µm; 32.2% of the points had width under 25 µm, while only 9.6% of them had width over 75 µm. The accuracy was 0.41, 0.54, 0.41, and 0.30 for NewTom VGi, Planmeca Promax 3D Max, Kavo 3D eXam, and Soredex Scanora3D, respectively. Conclusions: The modified temperature cycling method is a simple and effective method to establish narrow root fracture models, and the diagnosis efficiency for these narrow fracture lines was quite poor using all the four different CBCT units.