Endodontic Files Research Articles

Structural Assessment of Endodontic Files via Finite Element Analysis

A methodology for the structural assessment of Nickel-Titanium (Ni-Ti) endodontic files and a novel approach to predict their fatigue behavior using finite element method (FEM) were proposed. ProTaper-Universal F1 and F2 endodontic files were selected due to availability of extensive test data needed for the validation of the methodology. Bending and torsional loadings were analyzed since these provide essential data for the structural integrity assessment for the endodontic files. High-definition FEM models and their computationally efficient idealized versions were developed. The results for the bending and torsional stiffness of the F1 endodontic file agreed with the literature data validating the proposed methodology. Hysteresis energy density was shown to give promising results as a predictor of low cycle fatigue failure. The predictions with the idealized models matched those of the high-definition models, justifying the proposed idealizations. The validated models demonstrated that F2 has 60% higher bending and torsion resistance and 7% higher hysteresis energy density per cycle with respect to F1, leading to the conclusion that F1 has a lower structural stiffness but a longer fatigue life as compared to F2. In summary, the developed methodology allows for the structural and durability evaluation of various design parameters for Ni-Ti endodontic files.

Health prediction of reciprocating endodontic instrument based on the machine learning and exponential degradation models.

This study proposes an intelligent health prediction and fault prognosis of the endodontic file during the root canal treatment. Root canal treatment is the procedure of disinfecting the infected pulp through the canal with the help of an endodontic instrument. Force signals are acquired with the help of a dynamometer during the canal preparation, and statistical features are extracted. The extracted features are selected through the window-wise feature extraction process. Characteristic features for endodontic file prognostics include time-domain features of the signals are evaluated. The extracted feature has inappropriate information, that is, noise between the signals; hence the smoothing of the feature is required at this stage to observe a trend in the signals. Based on the smoothing feature and post-processing of the feature, defined the health index to calculate the health condition of the endodontic instruments. A machine learning algorithm and exponential degradation model are used to predict the health of the endodontic instrument during the root canal treatment. This model is used to forecast the degradation of the endodontic file so that actions can be taken before actual failures happen. The proposed methodology can analyze the failures and micro-crack initiation of the endodontic instruments. Endodontics practitioners can use the machine learning models as well as an exponential model for estimating the health condition of the endodontic instrument. This study may help the clinician to progress the efficiency of the root canal treatment and the competence of the endodontic instruments.

The Effect of Different Image Processing Techniques on the Measurement Accuracy of Endodontics File Length.

Different software capabilities have been used in digital systems to increase the diagnostic quality of radiographic projections. Considering the availability of different enhancement techniques, it is necessary to determine the suitability of each technique for various diagnostic cases. There is controversy between studies over the effect of different digital enhancement techniques on the accuracy of file length measurements in endodontics. The present in vitro study aimed to determine the effect of the software capabilities on the diagnostic accuracy to determine endodontic file lengths in photostimulable phosphor (PSP) radiographs. In the present in vitro study, standard access cavities were prepared in 44 extracted human single-rooted permanent teeth. An endodontic file was placed in each root canal. PSP sensors were used for digital imaging using the parallel technique. All the images were reviewed on a same monitor; once normally with no software enhancement and once using software manipulations including pseudo-color, sharpness, emboss, and edge enhancement. The distance from the file tip to the rubber stop was measured on the images by an electronic ruler. Significantly, all of the image enhancement techniques presented shorter measurements comparing to the actual length. The results revealed the significant accuracy of the measured error in the pseudo-color enhancement technique compared to other techniques. The results revealed significant differences between the initial measurements (the gold standard) and those made on the manipulated radiographs. In all cases, the measurements were significantly lower than the real values. Therefore, none of these digital enhancement techniques can increase the accuracy of file length measurements significantly. However, manipulation with the pseudo-color option resulted in fewer errors compared to other options and the normal images. Hence, for precise measurements of the endodontic file lengths, pseudo-color processing algorithm can be suggested when using PSP sensors.

Endodontic retreatment of mandibular molars with the presence of missed middle mesial root canals: An important clinical lesion

Aim: Untreated root canals may have a direct impact on root canal treatment (RCT) outcome. The aim of this case report is to describe the nonsurgical root canal retreatment of two mandibular first molars in a patient's mesial roots that had previously missed middle mesial root canals (MMC). Methodology: A 14-year-old female was referred to the our clinic with the complaint of pain in the posterior areas of the right and left mandibula. During the examination, previous RCTs [teeth 36 (mandibular left first molar) and 46 (mandibular right first molar)] were observed. Besides, these teeth have periradicular lesions in the mesial roots probably due to unsuccessful previous treatment. Nonsurgical retreatment was suggested and accepted. Access cavities were prepared and the unnoticed MMCs were detected at the isthmus connecting both mesiobuccal and mesiolingual canals. All the root canals were shaped with NiTi rotary endodontic files. During the shaping, the root canals were irrigated copiously with NaOCl, EDTA, clorhexidine, and saline solutions under a certain protocol. Calcium hydroxide was used for intracanal dressing. Gutta-percha and a resin-based root canal sealer were used for filling. Coronal restorations of the teeth were completed with a composite resin. Conclusion: At follow-up examinations after 3-, 6-, and 12-months, the teeth were asymptomatic and radiographically showed repair of the lesion. Healing was achieved without any need for further endodontic surgical intervention. How to cite this article: Başoğlu A, Harorlı H, Er K. Endodontic retreatment of mandibular molars with the presence of missed middle mesial root canals: an important clinical lesion. Int Dent Res 2023;13(2):99-103. https://doi.org/10.5577/idr.2023.vol13.no2.8 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

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Finite element analysis of bending and torsional loading of two different endodontic rotary files with different off-center geometric sections

Abstract The aim of this study was to evaluate the performance of two endodontic rotary files with different off-center geometries in bending and torsional tests using finite element analysis (FEA). Trunatomy Prime (TRN-P) and WaveOne Gold Primary (WOG-P) files were used in the study. Geometric models for finite element analysis were obtained by micro-computed tomography scanning. FEA analyses were performed according to ISO 3630-1 specifications to evaluate the bending and torsional tests of the files. Trunatomy Prime showed higher flexibility than WOG-P when subjected to bending. In terms of torsional strength, WOG-P showed higher torsional strength than TRN-P. The geometry of a rotary instrument file influences the mechanical behavior (bending and torsion) of rotary files. The clinician should be aware of the behavioral differences in rotary files and use the appropriate file according to the clinical situation in addition to the manufacturer’s instructions.

External Root Surface Temperature Control with 1,1,1,2-Tetrafluoroethane Intracanal Cryotherapy during Thermoplastic Obturation: An In Vitro Study.

The aim of this in vitro study was to determine the effectiveness of 1,1,1,2-tetrafluoroethane (TFE) intracanal cryotherapy for external root surface temperature control during thermoplastic obturation. Thirty extracted adult single-rooted mandibular incisors were selected for this study. Endodontic shaping was performed until size X3 Protaper Next Rotary endodontic file. The teeth were divided into three groups: Group I-Control group wherein conventional irrigation was done using physiologic saline stored at room temperature, Group II-Irrigational Cryotherapy group using physiologic saline at 2.5°C, and Group III-Intracanal TFE cryotherapy group with intracanal refrigerant TFE application. Temperatures were recorded in the apical 3 mm before and after completion of each intervention and post thermoplastic obturation using a noncontact digital laser infrared thermometer. Intracanal cryotherapy with TFE resulted in a mean decrease of 9.27°C compared with conventional irrigation that exhibited in a mean decrease of 2.13°C. Also, in intracanal cryotherapy group with TFE application, compared with the baseline (24.50°C), no significant differences were observed post obturation (24.61°C) with high-temperature-injectable gutta percha technique indicating good control of temperature rise on the external root surface. Intracanal cryotherapy with refrigerant TFE was highly effective in controlling temperature rise on the external root surface during injectable thermoplastic obturation technique. Minimizing deleterious effects due to high temperatures generated during the thermoplastic obturation is critical. Clinically feasible measures to reduce the transmission of heat generated during thermoplastic obturation have been searched since long. In this regard, intracanal cryotherapy with TFE can be effectively used to control the rise of temperature on the external root surface when employing thermoplastic obturation technique.

Cyclic and torsional fatigue resistance of a new rotary file on a rotary and reciprocating motion.

This study evaluated the cyclic and torsional fatigue resistance of a new nickel-titanium (Flat File 25.04) instrument on the continuous and reciprocating motion. Sixty instruments of the ProDesign Logic2 25.03 and 25.05 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), and MK Flat File 25.04 (n = 20) (MK Life, Porto Alegre, Brazil) were used. For the cyclic fatigue test, an artificial stainless steel simulated canal with an angle of 60° and a radius of curvature of 5 mm located 5 mm from its tip was used. The torque and rotation angle at the instruments' failure on the torsional fatigue test was based on the ISO 3630-1 protocol, in which the 3 mm tip of each instrument was fixed and connected to an electric motor and a load cell. The fractured surface of each fragment was examined by scanning electron microscopy. Data were analyzed using a 1-way analysis of variance and Tukey's test with a significance level of 5%. Flat File 25.04 had lower cyclic fatigue in both kinematics than the Logic instruments (p < .05). Reciprocating motion improved the cyclic fatigue of the tested instruments (p < .05). Flat File 25.04 had similar torque to Logic2 25.05 (p > .05), and both were superior to Logic2 25.03 (p < .05). The angular deflection values were different for the three tested instruments (p < .05), in the decreasing order: Logic2 25.03, 25.05, and Flat File 25.04. Flat File presented good resistance to cyclic and torsional fatigue resistance. Reciprocating motion improved the cyclic fatigue resistance of the instruments and can be considered when using programmable motors. RESEARCH HIGHLIGHTS: Scanning electron microscopy evaluation of different endodontic rotary file and fatigue resistance tests.

Comparative Evaluation of Debris Extrusion, Remaining Dentin Thickness and Fracture Resistance of Endodontically Treated Teeth Using Rotary and Reciprocating Endodontic File Systems: An In Vitro Study.

Preventing the apical extrusionof debris during instrumentation is of paramount importance to reduce theoccurrence of flare-ups in endodontically treated teeth. Furthermore, an essential requirement for the longevity andstrength of an endodontically treated tooth and its ability to resist fracture is the preservation of residual dentin thickness during instrumentation. The aim of this study was to compare the amount of debris extrusion, remaining dentin thickness at the coronal third, middle third, apical third, and the fracture resistance of the teeth using rotary (TruNatomy; Dentsply Sirona, Charlotte, NC) and reciprocating (WaveOne Gold; Dentsply Sirona) endodontic file systems. An in vitro study included 52 single-rooted, oval canal shaped teeth that underwent exploration and initial cleaning with a no. 15 K-file. The prepared canals were then randomly assigned to two groups: Group I, with instrumentation with the TruNatomy rotary file(n=26) and Group II, with instrumentation with the WaveOne Gold reciprocating file. Parameters like debris extrusion, remaining dentin thickness, and fracture resistance were evaluated in both the groups. Analysis was performed using a paired t-test for the assessment of difference between groups and one-way ANOVA test followed by the post-hoc Tukey test for difference between the coronal, middle and apical third for each study group. The results revealedno significant difference (t=0.454, p=0.652) between the TruNatomy rotary file and WaveOne Gold reciprocating filein apical extrusion of debris after their use in root canal therapy. For the remaining dentin thickness, a significant difference was present between the TruNatomy rotary file and WaveOne Gold reciprocating rotary file at the coronal (t=5.766, p<0.0001) and middle (t=3.690, p=0.001) levels. The mean fracture resistance was significantly more (t=15.877, p<0.0001) with the TruNatomy rotary file compared to the WaveOne Gold reciprocating rotary file. The TruNatomy rotary file system outperformed the WaveOne Gold reciprocating file system in terms of maintaining the remaining dentin thickness and providing improved fracture resistance. Nevertheless, debris extruded apically was comparable between the TruNatomy rotary file system and the WaveOne Gold reciprocating file system.

Cyclic Fatigue Resistance of Different Glide Path Files in Simulated Double Curved Canal in Continuous Rotary Motion: An In Vitro Study.

This in vitro study aimed to compare and evaluate the resistance to cyclic fatigue of a newly developed glide path file in a simulated double curvature canal in a cyclic fatigue-testing machine. In this in vitro study, a static cyclic fatigue-testing machine with a simulated double curve was created and the samples were divided into the following three groups: Group I-HyFlex EDM; group II-TruNatomy file; and group III-Aurum G files and each instrument is continued to rotate in the canal and a number of cycles to failure (NCF) was calculated and Fractographic analysis was done using scanning electron microscope (SEM), and the results were statistically analyzed. Statistical analysis was done using parametric methods one-way analysis of variance (ANOVA) shows statistical significance between groups and then Tukey's HSD post hoc tests were used for multiple pairwise comparisons. TruNatomy glide path files had the highest cyclic fatigue resistance when compared to HyFlex EDM and Aurum G files. The selection of file systems in cleaning and shaping protocols is an enigma to endodontics. From the results of this study, it can be concluded that TruNatomy files had higher cyclic fatigue resistance than other glide path files are canals with double curvature, hence it is suitable for usage in root canals with extreme curvature. The selection of file systems in cleaning and shaping protocols is an enigma to endodontics. This in vitro study explored the selection protocols for the execution of root canal preparation. Heat treatment of nickel-titanium (NiTi) endodontic files had improved the cyclic fatigue resistance significantly enhancing the clinical life of file systems.

A Minimally Invasive Technique for the Retrieval of Fractured Root Tips.

Exodontia, the removal of a compromised tooth, ideally consists of the painless removal of the tooth or tooth root, with minimal trauma to the surrounding tissues, resulting in complete healing without creating postoperative prosthetic problems. Fractures of the tooth's root tip during exodontia can be common in some cases, such as in teeth with irregular root morphology or severely decayed teeth. The current article presents a technical report in which endodontic files made it possible to remove a fractured root tip from a maxillary third molar without using force.

Push-out Bond Strength of Fiber Posts in Long-Term Hypobaric Pressure Changes.

BACKGROUND: The purpose of this study was to evaluate the bond strength of fiber posts with different mixing methods and insertion into root canal techniques in long-term hypobaric pressure changes.METHODS: We chose and decoronated 42 teeth with straight and single root canals. After post-space preparation, the posts were cemented with hand-mixed and auto-mixed resin cements that were inserted into the canals with an endodontic file (lentilo), dual-barrel syringe, and root canal tip (14 for each group). After cementation, each group was divided into two subgroups (N = 7): the control (ambient pressure) group and the hypobaric pressure group. The samples were exposed to hypobaric pressure 90 times. They were cut into 2-mm-thick segments and the push-out bond strength test was performed using a Universal Testing Machine. One-way ANOVA tests, Bonferroni tests, and Student-t-tests were used for statistical analysis.RESULTS: The environmental pressure changes and insertion techniques affected the bond strength values. The auto-mixed with root-canal tip group showed the highest push-out bond strength values in both hypobaric (dual-barrel syringe group: 10.01 MPa; root-canal tip group: 11.61 MPa) and control (dual-barrel syringe group: 12.29 MPa; root-canal tip group: 14.58 MPa) group. In all root segments, the bond strength values of hypobaric groups were lower than atmospheric pressure groups. The most frequent failure type was adhesive between dentin and cement in all groups.DISCUSSION: Dentists should use auto-mixed self-adhesive resin with a root canal tip for post cementations in patients likely to be exposed to hypobaric pressure changes.Ozkan Ata S, Ata N, Yazgan E, Akkor T. Ugurlutan R. Push-out bond strength of fiber posts in long-term hypobaric pressure changes. Aerosp Med Hum Perform. 2023; 94(7):508-513.

Investigation of the Use of TiO2 Obtained from Endodontic NiTi Files in Dye-Sensitized Solar Cells

Artan enerji taleplerin karşılanmasında yenilenebilir enerji türleri açısından popüler olan fotovoltaik teknolojiler üzerine verim artırmaya yönelik çalışmalar yapılmaktadır. Boya duyarlı güneş pilleri yüksek altyapı maliyeti gerektirmeyen yapılar olduğundan verim artırmaya yönelik çalışmalar boya duyarlı güneş hücreleri (DSSC) üzerine yoğunlaşmıştır. DSSC’de ışığa duyarlı boya, TiO2 tabakasına tutundurulmaktadır. Kullanım ömrünü tamamlamış NiTi alaşımı endodontik eğeler, farklı asitler üzerinden çözeltiye alınıp metalik değerlerine ayrıştırılmış ve bu metalik değerlerden olan anataz fazında olduğu tespit edilen TiO2 ‘nin boya duyarlı güneş hücrelerinde kullanımına yönelik çalışmalar yapılmıştır. Çalışma kapsamında atık NiTi eğelerden elde edilen kontamine TiO2 ‘nin yapısı karakterize edilmiş ve N719 boya çözeltisinin yüzeye tutundurularak optik özellikleri araştırılmıştır. Boya duyarlı güneş hücrelerinde kullanılan N719 boya çözeltisi uygulanan geri kazanım anataz TiO2 tatbik edilmiş yüzeyle ile görünür bölge spektrumunda belirgin bir etkinlik göstermediği ortaya konulmuştur.

Comparative Evaluation of a Dynamic Navigation System versus a Three-dimensional Microscope in Retrieving Separated Endodontic Files: An In Vitro Study

IntroductionThis study aimed to compare the effectiveness of a dynamic navigation system and a three-dimensional microscope in retrieving broken rotary Nickel-Titanium files when using trepan burs and the extractor system. Materials and MethodsThirty maxillary first bicuspids with 60 separate roots were split into 2 comparable groups based on a comprehensive cone beam computed tomography analysis of the root length and curvature. After standardized access opening, glide paths, and patency attainment with the K file (sizes 10 and 15), the teeth were arranged on 3D models (three per quadrant, six per model). Subsequently, controlled-memory heat-treated Nickel-Titanium rotary files (#25/0.04) were notched 4 mm from the tips and fractured at the apical third of the roots. The C-FR1 Endo file removal system was employed under both guidance to retrieve the fragments, and the success rate, canal aberration, treatment time, and volumetric changes were measured. The statistical analysis was performed using IBM SPSS software at a significance level of 0.05. ResultsThe microscope-guided group had a higher success rate than the dynamic navigation system guidance, but the difference was insignificant (P > .05). In addition, the microscope-guided drills resulted in a substantially lower proportion of canal aberration, shorter time to retrieve the fragments and less change in the root canal volume (P < .05). ConclusionAlthough dynamically guided trephining with the extractor can retrieve separated instruments, it is inferior to three-dimensional microscope guidance regarding treatment time, procedural errors, and volume change.

Cyclic fatigue resistance of three reciprocating nickel-titanium instruments with heat treatment at intrachannel temperature

Introduction: the in vitro study compared the dynamic cyclic fatigue resistance of 3 reciprocating NiTi files with heat treatment. Methods: we distributed 30 new endodontic files in three groups. The endodontic files selected for this experiment were: AF Blue R3 25/06 (AFB) (Fanta Dental, Shanghai, China), X1 Blue File 25/06 (X1B) (MK Life, Porto Alegre, RS, Brazil), and Reciproc Blue 08/25 (RB) (VDW, Munich, Germany. We measured the time to file fractureand the length of the fractured fragment. ANOVA analysis was used, followed by the Tukey test for multiple comparisons, with a significance level of 5% (P &lt; 0.05). Results: the mean time in seconds until the file fractured was 170.7 ±15.1 for AFB files, 110.4 ±26.8 for X1B, and 163.3 ±22.9 for RB files. This difference was statistically significant when comparing X1B to AFB (p: 0.000) and X1B to RB (p: 0.000). However, there are no statistically significant differences between RB and AFB (p:0.739). Conclussions: this study found that RB and AFB files exhibit similar resistance to cyclic fatigue.

Effect of Stabilized Martensite on the Long-Term Performance of Superelastic NiTi Endodontic Files.

One of the most used rotary files in endodontics is NiTi files due to their superelastic properties. This property means that this instrument has extraordinary flexion that can adapt to large angles inside the tooth canals. However, these files lose their superelasticity and fracture during use. The aim of this work is to determine the cause of fracture of the endodontic rotary files. For this purpose, 30 NiTi F6 SkyTaper® files (Komet, Germany) were used. Their chemical composition was determined by X-ray microanalysis, and their microstructure was determined by optical microscopy. Successive drillings were carried out with artificial tooth molds at 30, 45, and 70°. These tests were carried out at a temperature of 37 °C with a constant load controlled by a high sensitivity dynamometer of 5.5 N, and every five cycles were lubricated with an aqueous solution of sodium hypochlorite. The cycles to fracture were determined, and the surfaces were observed by scanning electron microscopy. Transformation (austenite to martensite) and retransformation (martensite to austenite) temperatures and enthalpies were determined by Differential Scanning Calorimeter at different endodontic cycles. The results showed an original austenitic phase with a Ms temperature of 15 °C and Af of 7 °C. Both temperatures increase with endodontic cycling, indicating that martensite forms at higher temperatures, and the temperature must be increased with cycling to retransform it to austenite. This fact indicates the stabilization of martensite with cycling, which is confirmed by the decrease in both transformation and retransformation enthalpies. The martensite is stabilized in the structure due to defects and does not retransform. This stabilized martensite has no superelasticity and, therefore, fractures prematurely. It has been possible to observe the stabilized martensite by studying the fractography, observing that the mechanism is by fatigue. The results showed that the files fracture earlier the greater the angle applied (for the tests at 70° at 280 s, at 45° at 385 s, and at 30° at 1200 s). As the angle increases, there is an increase in mechanical stress, and, therefore, the martensite stabilizes at lower cycles. To destabilize the martensite, a heat treatment can be carried out at 500 °C for 20 min, and the files recovers all its superelasticity.

Removing Fractured Endodontic Files with a Tube Technique-The Strength of the Glued Joint: Tube-Endodontic File Setup.

One recommended technique for removing broken root canal instruments is to glue the fragment into a cannula adapted to it (i.e., the tube technique). The aim of the study was to determine the influence of the adhesive kind and length of the joint on the breaking force. During the investigation, 120 files (60 H-files and 60 K-files) and 120 injection needles were used. Fragments of broken files were glued into the cannula using one of three materials: cyanoacrylate adhesive, composite prosthetic cement, or glass ionomer cement. The lengths of the glued joints were 2 and 4 mm. After the polymerization of adhesives, a tensile test was carried out to find a breaking force. The results were statistically analyzed (p < 0.05). For 4 mm lengths of glued joints, the breaking force was higher than for 2 mm for both file types (K and H). In the case of K-type files, the breaking force was higher for cyanoacrylate and composite adhesives than glass ionomer cement. For H-type files, no significant difference in joint strength was found between binders at 4 mm, while at 2 mm, a much better connection was obtained for cyanoacrylate glue than prosthetic cements.

Experimental Analysis of the Influence of Heat Treatments on the Flexibility of NiTi Alloy for Endodontic Instruments Manufacturing.

The flexibility of NiTi based endodontic files is improved by heat treatment, leading to lower risk of failure, ledges, and canal transportation during the preparation of curved root canals. The aim of this study is to investigate and clearly highlight the influence of every parameter of heat treatment on the flexibility of NiTi wires and thus of endodontic instruments. A full factorial Design of Experiment (DoE) and a designed bending-torsion bench following the ISO 3630-1 standard were used for this investigation. Temperature, holding time, and cooling method were selected as contributing factors, while maximum bending moment, hysteresis size, and stiffness during martensitic transformation were selected as outputs. Regression analysis was performed to estimate the relationship between contributing and output variables to assess how the experimentation fits with the model. The experimental results showed that wires heated at 425 °C for 30 min are more flexible. Moreover, heat treatment temperature is the most critical factor influencing the flexibility and hysteresis size of the NiTi wire followed by the holding time, while the cooling method has a negligible effect. The regression analysis showed that the model is effective at predicting the relationship between contributing factors, bending moment response, and hysteresis size.

Prognostic Health Management Using IR Thermography: The Case of a Digital Twin of a NiTi Endodontic File.

Prognostic and health management technologies are increasingly important in many fields where reducing maintenance costs is critical. Non-destructive testing techniques and the Internet of Things (IoT) can help create accurate, two-sided digital models of specific monitored objects, enabling predictive analysis and avoiding risky situations. This study focuses on a particular application: monitoring an endodontic file during operation to develop a strategy to prevent breakage. To this end, the authors propose an innovative, non-invasive technique for early fault detection based on digital twins and infrared thermography measurements. They developed a digital twin of a NiTi alloy endodontic file that receives measurement data from the real world and generates the expected thermal map of the object under working conditions. By comparing this virtual image with the real one acquired by an IR camera, the authors were able to identify an anomalous trend and avoid breakage. The technique was calibrated and validated using both a professional IR camera and an innovative low-cost IR scanner previously developed by the authors. By using both devices, they could identify a critical condition at least 11 s before the file broke.

Retrospective Analysis of Artifacts in Cone Beam Computed Tomography Images Used to Diagnose Chronic Rhinosinusitis.

Cone beam computed tomography (CBCT) is frequently used to corroborate the signs and symptoms of chronic rhinosinusitis (CRS). However, artifacts induced by dental restorations might complicate the diagnosis of CRS. Here, we assessed the frequency and location of artifacts in CBCT images taken to confirm the CRS. All CBCT images of the patients referred to the Emergency Radiology unit, Turku University Hospital, with an indication of CRS in 2017 were re-examined. The prevalence of the artifacts was analyzed in three cross-sectional views and three horizontal levels delimited by anatomical landmarks. In total, 214 CBCT images of patients with CRS were evaluated. The diagnosis of apical periodontitis (AP) was impaired by artifacts present in 150/214 images (70%). The diagnosis of CRS was impaired in 5 of the 214 images (2.3%). The main origins of the artifacts were large dental fillings or crowns, and endodontic fillings were present in 95% (203/214) and 52% (111/214) of the images, respectively. AP as an etiology of CRS is possible to miss because of artifacts originating from dental and endodontic fillings in the CBCT images of the paranasal sinuses.