Expert consensus on endodontic therapy for patients with systemic conditions.

The overall health condition of patients significantly affects the diagnosis, treatment, and prognosis of endodontic diseases. A systemic consideration of the patient's overall health along with oral conditions holds the utmost importance in determining the necessity and feasibility of endodontic therapy, as well as selecting appropriate therapeutic approaches. This expert consensus is a collaborative effort by specialists from endodontics and clinical physicians across the nation based on the current clinical evidence, aiming to provide general guidance on clinical procedures, improve patient safety and enhance clinical outcomes of endodontic therapy in patients with compromised overall health.

The trend of radiographic healing after root canal treatment in teeth with apical periodontitis based on cone-beam computed tomography: A 4-year longitudinal study.

OBJECTIVES: The aim of this study was to observe the radiographic healing of periapical lesions after root canal treatment via volumetric measurements based on cone-beam computed tomography (CBCT) over 4 years. METHODS: In total, 162 single-root teeth from patients with chronic periapical periodontitis who underwent primary root canal treatment were included in this retrospective study. Follow-up visits were scheduled at 1, 2, and 4 years after treatment. The volume of radiolucency at pretreatment and follow-up were measured, and the radiographic outcomes were classified into 4 categories: absence, reduction, uncertain or enlargement. Reduction or enlargement was considered when the volumetric change in radiolucency was 20 % or more. RESULTS: During the 4-year follow-up period, 128 teeth were reviewed at least once, including 3 extracted teeth. Of the remaining 125 teeth, the volume of radiolucency was reduced in 116 teeth (90.6 %), uncertain in 5, and enlarged in 4 teeth during 1 to 4 years after treatment. Among the 43 teeth with reduced radiolucency at 1 year after treatment, 42 (97.7 %) had continuing reduced lesions at 4 years. In the 2 teeth with enlarged radiolucency at 1 year, the volume of radiolucency doubled at 4 years. Cox regression analysis revealed that the preoperative radiolucency size was a risk factor for persistent periapical radiolucency. CONCLUSIONS: The efficacy of root canal treatment for apical periodontitis was predictable. When the radiolucency changed by 20 % or more in volume on CBCT scans at 1 year after treatment, reversal of the radiographic healing tendency was rare. CLINICAL SIGNIFICANCE: The volumetric changes in radiolucency on CBCT could reflect trends in the healing process and may foster early clinical decision-making.

Radiomics analysis of pancreas based on dual-energy computed tomography for the detection of type 2 diabetes mellitus.

Objective: To utilize radiomics analysis on dual-energy CT images of the pancreas to establish a quantitative imaging biomarker for type 2 diabetes mellitus. Materials and methods: In this retrospective study, 78 participants (45 with type 2 diabetes mellitus, 33 without) underwent a dual energy CT exam. Pancreas regions were segmented automatically using a deep learning algorithm. From these regions, radiomics features were extracted. Additionally, 24 clinical features were collected for each patient. Both radiomics and clinical features were then selected using the least absolute shrinkage and selection operator (LASSO) technique and then build classifies with random forest (RF), support vector machines (SVM) and Logistic. Three models were built: one using radiomics features, one using clinical features, and a combined model. Results: Seven radiomic features were selected from the segmented pancreas regions, while eight clinical features were chosen from a pool of 24 using the LASSO method. These features were used to build a combined model, and its performance was evaluated using five-fold cross-validation. The best classifier type is Logistic and the reported area under the curve (AUC) values on the test dataset were 0.887 (0.73-1), 0.881 (0.715-1), and 0.922 (0.804-1) for the respective models. Conclusion: Radiomics analysis of the pancreas on dual-energy CT images offers potential as a quantitative imaging biomarker in the detection of type 2 diabetes mellitus.

Expert consensus on irrigation and intracanal medication in root canal therapy.

Chemical cleaning and disinfection are crucial steps for eliminating infection in root canal treatment. However, irrigant selection or irrigation procedures are far from clear. The vapor lock effect in the apical region has yet to be solved, impeding irrigation efficacy and resulting in residual infections and compromised treatment outcomes. Additionally, ambiguous clinical indications for root canal medication and non-standardized dressing protocols must be clarified. Inappropriate intracanal medication may present side effects and jeopardize the therapeutic outcomes. Indeed, clinicians have been aware of these concerns for years. Based on the current evidence of studies, this article reviews the properties of various irrigants and intracanal medicaments and elucidates their effectiveness and interactions. The evolution of different kinetic irrigation methods, their effects, limitations, the paradigm shift, current indications, and effective operational procedures regarding intracanal medication are also discussed. This expert consensus aims to establish the clinical operation guidelines for root canal irrigation and a position statement on intracanal medication, thus facilitating a better understanding of infection control, standardizing clinical practice, and ultimately improving the success of endodontic therapy.

[Root canal therapy of maxillary molars with atypical canals: A report of three cases].

Maxillary molar with three roots and 3 to 4 canals is a common occurrence. However, in addition to common root canal anatomy, there may be significant differences in the number, distribution, and morphological structure of root canals. The success of root canal treatment is dependent on ensuring that all the intricate details associated with it are meticulously followed. Failure to locate all canals could have a negative effect on the treatment as it may lead to initiation or continuation of periapical pathology. Missed canals were the main reason for patients reporting back for nonsurgical root canal retreatment. Moreover, the bacteria residing in such canals could also result in persistence of symptoms. Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This article presents three cases of endodontic management of maxillary molars with atypical canal morphology. In the three cases of this study, the patients underwent cone beam computed tomographic (CBCT) examination before root canal treatment. The CBCT images revealed that the maxillary molars in case 1 and case 2 had 5 canals. Case 1: 2 mesiobuccal (MB, MB2), two distobuccal (DB and DB2), and one palatal canal. Case 2: 2 mesiobuccal (MB, MB2), one distobuccal (DB), and two palatal canals (MP and DP). In case 3, CBCT scan slices showed that the maxillary first molar presented as a C-shaped root canal with a rare tooth anomaly of taurodontism. Although C-shaped root canals were most frequently seen in the mandibular second molar, they might also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. Case 3 described the fusion between mesiobuccal and palatal roots of the maxillary first molar, forming a C-shaped mesiopalatal root canal. The above cases suggest that endodontists should always be aware of aberrancies in root canal system apart from the knowledge of normal root canal anatomy. CBCT as a means of diagnosis can be helpful for identifying and managing these complex root canal systems. This case series also highlights the importance of magnification and illumination. Through using an endodontic microscope, clinicians can identify root canals that are difficult to locate or overlooked with normal vision. A correct access opening is a most important step to locate and negotiate the orifices of root canals. The use of ultrasonic tips can refine the access cavity and allow controlled and delicate removal of calcifications and other interferences to the canal orifices, thereby helping to locate the extra orifices.

Outcome of chairside CAD/CAM ceramic restorations on endodontically treated posterior teeth: a prospective study.

OBJECTIVE: The aim of this study was to evaluate the outcome and risk factors for chairside CAD/CAM full cusp coverage restorations on endodontically treated posterior teeth after 3 years of follow-up. METHODS: A total of 245 endodontically treated posterior teeth of 224 patients were included and restored with CAD/CAM full cusp coverage all-ceramic restorations according to a standardized protocol. Patients were recalled after treatments 1 to 3 years and underwent clinical and radiological examinations. At recall, modified FDI criteria were used to determine treatment outcomes by 2 evaluators. Success was determined when FDI scores were 1-2, and failure was indicated when FDI scores were 5. Logistic regression analysis was performed to evaluate potential risk factors. RESULTS: A total of 183 patients presented at recall, and the clinical outcomes of 201 teeth were analyzed with a recall rate of 82.0% for teeth and 81.7% for patients after 1-3 years of follow-up.185 of 201 teeth were found to have FDI scores of 1-2, and the success rate was 92%. No teeth were extracted during the follow-up period. Fourteen failed cases with an FDI score of 5 presented restoration dislocation, fracture of restoration or/and tooth. Logistic regression analysis revealed that oral parafunction (OR 2.281, 95% CI 2.2 ~ 47.5, P value 0.01) was a risk factor for success rate. CONCLUSION: Chairside CAD/CAM all-ceramic full cusp coverage restoration was (could be) a promising alternative for restoring endodontically treated posterior teeth.

Characterization of SARS-CoV-2-specific humoral immunity and associated factors in the healthy population post-vaccination.

OBJECTIVES: To investigate factors that may influence humoral immunity post-vaccination with a COVID-19-inactivated vaccine (SC2IV). METHODS: A total of 1596 healthy individuals from the Seventh Affiliated Hospital, Sun Yat-sen University (1217) and Shenzhen Baotian Hospital (379) were enrolled in this study among which 694 and 218 participants were vaccinated with two-dose SC2IV, respectively. Physical examination indices were recorded. The levels of neutralizing antibody (NA), Spike IgG, receptor-binding domain (RBD) IgG, RBD IgG + IgM + IgA, and nucleocapsid IgG of SARS-CoV-2 were measured by a non-virus ELISA kit. Multiple statistical analyses were carried out to identify factors that influence humoral immunity post-vaccination. RESULTS: The two-dosage vaccination could induce NA in more than 90 % of recipients. The NA has the strongest correlation with anti-RBD IgG. Age is the most important independent index that affects the NA level, while basophil count, creatine kinase-MB, mean corpuscular hemoglobin, the ratio of albumin to urine creatinine, and thyroglobulin antibody have relatively minor contributions. Indices that affect the NA level were different between males and females. Antibodies targeting other epitopes of SARS-CoV-2 were detected in recipients without anti-RBD. CONCLUSIONS: The factors identified in association with the NA level post-vaccination may help to evaluate the protective effect, risk of re-infection, the severity of symptoms, and prognosis for vaccine recipients in clinical.

Clinical Outcome and Predictors of Endodontic Microsurgery Using Cone-beam Computed Tomography: A Retrospective Cohort Study.

INTRODUCTION: The aim of this retrospective cohort study was to evaluate the clinical outcomes and identify the prognostic factors of endodontic microsurgery based on cone-beam computed tomographic (CBCT) scans. METHODS: Patients who underwent endodontic microsurgery in teeth with asymptomatic apical periodontitis were included. The clinical outcomes were determined based on clinical and radiographic examinations after surgery 12-48 months. Radiographic healing was assessed on CBCT images by using the modified PENN 3-dimensional criteria and classified into 4 categories: complete, limited, uncertain, and unsatisfactory healing. Multivariate logistic regression was performed to detect outcome risk factors. RESULTS: Of the 204 teeth in 173 invited patients, 148 teeth of 126 patients were examined at review. On CBCT images, 88 teeth (59.5%) showed complete healing, and 42 (28.4%) teeth showed limited healing. All these 130 teeth were asymptomatic and achieved a clinical success rate of 87.8%. Uncertain healing was observed in 9 teeth, one of which was symptomatic. The remaining 9 teeth were unsatisfactory healing on CBCT scans, including 6 teeth with clinical symptoms and 3 free. Lesion type and root-end filling quality were significant outcome predictors (P < .05). The risk of treatment failure for teeth with combined endodontic-periodontal lesions was 8.6 times higher than that for teeth with isolated endodontic lesions. Adequate root-end filling quality improved the probability of success by 5.3 times. CONCLUSIONS: Based on CBCT data, an adequate performed endodontic microsurgery could have predictable success in teeth without periodontal involvement.

Cost-effectiveness analysis: nonsurgical root canal treatment versus single-tooth implant.

BACKGROUND: Economic evaluation of nonsurgical root canal treatment (NSRCT) and single-tooth implant (STI) provides useful information for medical decision. This retrospective study aimed to evaluate the cost-effectiveness of NSRCT versus single-tooth implant (STI) after 5-year treatment in a university affiliated hospital in Beijing, China. METHODS: 211 patients who underwent NSRCT and 142 patients who had STI were included and recalled after 5-year treatment. The propensity scores were used to match the cases of two treatment modalities. At recall, outcomes were determined based on clinical and radiographical examinations. For endodontically treated cases, absence or reduction of radiolucency were defined as success. Marginal bone loss (MBL) ≤ 4 mm were determined as success for implant cases. Direct and indirect costs were calculated in China Yuan (CNY). Patients' willingness to pay (WTP) for each treatment modality was evaluated by questionnaires. A cost-effectiveness analysis was performed from the societal perspective. RESULTS: 170 patients with 120 NSRCT teeth and 96 STI were available at recall. Based on propensity score matching, 76 endodontically treated teeth were matched to 76 implants. Absence of the radiolucency was observed in 58 of 76 endodontically treated teeth (76%) and reduction of the radiolucency in 9 of 76 teeth (12%) and altogether the success rate was 88%. 100% implants were detected with marginal bone loss (MBL) ≤ 4 mm. The cost advantage of NSRCT (4,751 CNY) over STI (20,298 CNY) was more pronounced. Incremental cost effectiveness ratio (ICER) was 129,563 CNY (STI-NSRCT) per success rate gained. It exceeded the patients' willingness to pay value 7,533 CNY. CONCLUSIONS: Clinical outcomes of NSRCT and STI could be predictable after 5-year treatment. NSRCT may be more cost-effective than STI for managing endodontically diseased teeth.

Effect of different dentin moisture on the push-out strength of bioceramic root canal sealer.

Background/purpose: Different moisture condition may affect the adhesion between obturation materials and root canal walls, thus further affect the quality of root canal obturation. The aim of this study was to evaluate the influence of dentin moisture conditions after different root canal drying protocols on the push-out strength of bioceramic root canal sealer. Materials and methods: Twenty root canals from extracted human decoronated premolars were prepared in vitro to #30/0.09 taper and assigned to 4 moisture condition groups after using different root canal drying protocols: normal moisture (paper point) group: the canals were blot dried with paper points until the last one appeared dry. Ethanol dry group: the canals were dried with paper points followed by dehydration with 95% ethanol. Isopropanol dry group: the canals were dried with paper points followed by dehydration with 70% isopropanol. Complete dry group: the canals were dried in an air-blowing thermostatic oven for at least 6 h until there was no change in weight at an interval of 1 h. After drying, the canals were obturated with bioceramic sealer iRoot SP. Then, each root was sectioned into eight slices with 1-mm-thick using a diamond saw (40 slices each group). The push-out strength was tested for each slice between the sealer and dentin wall using a universal testing machine at a crosshead speed of 0.5 mm/min, and failure modes were recorded. Two-way analysis of variance and Tukey test were used to analyze the push-out strength. Logarithmic linear regression analysis was used to compare the failure modes. Results: Push-out strength was statistically different in different moisture groups (P < 0.05). After drying using paper point, iRoot SP specimens showed the highest push-out strength (2.04 ± 0.03 MPa), followed by 95% ethanol, 70% isopropanol. The lowest push-out strength (0.68 ± 0.04 MPa) was observed under complete dry. For the failure modes, the majority were cohesive failures in the coronal and middle thirds of the root; while in the apical third, mixed failure was common. Conclusion: Different drying protocols influenced the push-out strength between bioceramic sealer and canal wall.

Pancreatic fat fraction in dual-energy computed tomography as a potential quantitative parameter in the detection of type 2 diabetes mellitus.

PURPOSE: To investigate the clinical value of measuring pancreatic fat fraction using dual-energy computed tomography (DECT) in association with type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: This retrospective study included patients who underwent abdominal DECT between September 2021 and July 2022. The fat fractions in the head, body, and tail of the pancreas were calculated using fat maps generated from unenhanced DECT images, and CT values were measured at the same locations. The intraclass correlation coefficient (ICC) was used to analyze the reproducibility of measurements from two observers. Diagnostic performance was assessed using receiver operating characteristic curves. RESULTS: Seventy-eight patients, including 45 T2DM patients and 33 controls, were enrolled. The fat fractions of the pancreas were significantly higher in the T2DM group than in the control group (pancreatic head: 8.4 ± 6.3 % vs 5.1 ± 3.9 %; pancreatic body: 4.8 ± 4.0 % vs 2.7 ± 3.9 %; and pancreatic tail: 5.3 ± 3.2 % vs 2.7 ± 2.9 %, all p < 0.05). And the CT values of the pancreas were significantly lower in the T2DM group than in the control group (pancreatic head: 41.1 ± 8.5 HU vs 45.7 ± 4.6 HU; pancreatic body: 44.4 ± 5.0 HU vs 47.4 ± 3.7 HU; and pancreatic tail: 44.5 ± 5.0 HU vs 47.6 ± 3.2 HU, all p < 0.05). The fat fraction of the pancreatic tail was the best indicator for distinguishing T2DM patients from the controls (area under the curve: 0.716 (95 % CI: 0.601, 0.832), sensitivity: 64.4 % (95 % CI: 48.7 %, 77.7 %), and specificity: 78.8 % (95 % CI: 60.6 %, 90.4 %)). CONCLUSION: The DECT fat fractions of the pancreas could be a valuable additional parameter in the detection of T2DM.

Detection of Proximal Caries Lesions on Bitewing Radiographs Using Deep Learning Method.

This study aimed to evaluate the validity of a deep learning-based convolutional neural network (CNN) for detecting proximal caries lesions on bitewing radiographs. A total of 978 bitewing radiographs, 10,899 proximal surfaces, were evaluated by two endodontists and a radiologist, of which 2,719 surfaces were diagnosed and annotated with proximal caries and 8,180 surfaces were sound. The data were randomly divided into two datasets, with 818 bitewings in the training and validation dataset and 160 bitewings in the test dataset. Each annotation in the test set was then classified into 5 stages according to the extent of the lesion (E1, E2, D1, D2, D3). Faster R-CNN, a deep learning-based object detection method, was trained to detect proximal caries in the training and validation dataset and then was assessed on the test dataset. The diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic curve were calculated. The performance of the network in the overall and different stages of lesions was compared with that of postgraduate students on the test dataset. A total of 388 carious lesions and 1,435 sound surfaces were correctly identified by the neural network; hence, the accuracy was 0.87. Furthermore, 27.6% of lesions went undetected, and 7% of sound surfaces were misdiagnosed by the neural network. The sensitivity, specificity, PPV, and NPV of the neural network were 0.72, 0.93, 0.77, and 0.91, respectively. In contrast with the network, 52.8% of lesions went undetected by the students, yielding a sensitivity of only 0.47. The F1-score of the students was 0.57, while the F1-score of the network was 0.74 despite the accuracy of 0.82. A significant difference in the sensitivity was found between the model and the postgraduate students when detecting different stages of lesions (p < 0.05). For early lesions which limited in enamel and the outer third of dentin, the neural network had sensitivities all above or at 0.65, while students showed sensitivities below 0.40. From our results, we conclude that the CNN may be an assistant in detecting proximal caries on bitewings.

Distinctive microbiota distribution from healthy oral to post-treatment apical periodontitis.

Post-treatment apical periodontitis (PoAP) occurs when root canal treatment has not adequately eliminated bacterial invasion and infection. Yet little is known about the bacterial composition and changes related to the etiology and pathogenesis of PoAP. In this study, clinical samples classified as root apex (HARD) and periapical granulation tissues (SOFT) were separately collected from 10 patients with PoAP. The microbiota of each sample was characterized by 16S rRNA gene sequencing, and the obtained dataset was coanalyzed with 20 NCBI sequence read archive (SRA) datasets of healthy oral (HO) and primary apical periodontitis (PAP). We observed 2522 operational taxonomic units (OTUs) belonging to 29 phyla, and all samples shared 86.5% of the sequence reads. The OTUs affiliated with Bacteroidetes, Firmicutes, Proteobacteria, Fusobacteria, and Actinobacteria, were identified as core microbiota, which accounted for nearly 90% of 16S rRNA sequences in all samples. However, the principal coordinates analysis (PCoA) of the beta diversity demonstrated that the three periapical statuses have distinct microbial compositions. Compared with HO and PoAP, Actinomyces has a significantly increased abundance in PAP. The microbial diversities in PoAP were significantly lower than those in the HO and PAP (p<0.05). The relative abundance of most bacterial taxa was decreasing, except that Clostridia and Synergistia were increased. Furthermore, we explored the potential metabolic differences of the microbial communities by KEGG pathway prediction. We revealed that the microbiota of PoAP might have a more active metabolic capacity, including carbohydrate metabolism, energy metabolism, and enzyme cofactor/carrier biosynthesis (p<0.05). Our study revealed that invasion of opportunistic pathogens such as Clostridia and Synergistia might play a significant role in PoAP, thus guiding the further study of complex microbial-host interactions and the development of more effective diagnostic and therapeutic methods.

Physicochemical properties of a novel bioceramic silicone-based root canal sealer.

Background/purpose: With introduction into endodontics, bioceramic-based sealers have gained considerable popularity for excellent properties. The aim of this study was to investigate the physicochemical properties of a novel bioceramic silicone-based sealer, GuttaFlow Bioseal, and measure heat flow of setting reactions. Materials and methods: Film thickness, flow, working and setting time of Bioseal were compared with other 4 kinds of sealers: iRoot SP, AH Plus, RoekoSeal and GuttaFlow2. Differential scanning calorimetry test was performed to measure heat flow. Results: Bioseal demonstrated the highest film thickness of 44 µm, double to triple that of the other 4 sealers (P < 0.05). The highest flow was detected in iRoot SP and RoekoSeal, with values of 27.35 and 27.20 mm, while GuttaFlow2 and Bioseal had the lowest of 22.31 and 21.43 mm (P < 0.05). For each sealer, working time at 37 °C was shorter than that at 23 °C (P < 0.05). At 37 °C, Bioseal had the shortest working and setting time of 4.5 and 16.3 min, while iRoot SP showed the longest of 105.0 and 571.7 min (P < 0.05). Differential scanning calorimetry test revealed that setting process of all the tested sealers was exothermic. Bioseal reached an exothermic peak at 14 min, with almost 1.5 times peak intensity of GuttaFlow2 and RoekoSeal. Whereas iRoot SP and AH Plus reached an exothermic peak 5 h after mixing, with intensity 1/2 to 2/3 that of Bioseal. Conclusion: The novel bioceramic silicone-based sealer Bioseal showed intense and fast exothermic reactions with characteristic physicochemical properties.

Fracture resistance of endodontically treated teeth with cervical defects using different restorative treatments.

Background/purpose: The restoration of endodontically treated teeth (ETT) with cervical defects has been a challenge for dentists. The purpose of this study was to evaluate the effect of restorative treatment on the fracture resistance of ETT with cervical defects. Materials and methods: One hundred and twenty freshly extracted human intact straight-single-root maxillary premolars were randomly divided into 6 groups. Group 1 remained untreated. Cervical defects of 4 mm-depth and 3 mm-height were created in groups 2-6. Group 3-6: root canal treatment. Group 4: direct composite resin restoration. Group 5: 2-mm full-cusp-coverage composite resin restoration. Group 6: fiber-post-supported composite resin restoration. A static fracture test was used to determine the fracture resistance of teeth under axial (n = 10) and palatal (30°) (n = 10) loading. Fracture modes were categorized as restorable and unrestorable. Results: Compared with intact teeth, the axial fracture resistance of teeth with cervical defects decreased by approximately 39%, and endodontic procedures resulted in 10% more reduction. When ETT with cervical defects were restored using direct composite resin filling, the axial fracture resistance recovered to 72% of that of intact teeth, but no significant change occurred under oblique loading. After full-cusp-coverage or fiber-post-supported restoration, fracture resistance showed complete recovery to the value of intact teeth (P > 0.05). Sixty percent of fractures were unrestorable for fiber-post-supported teeth, while in the full-cusp-coverage restoration group, 80-90% of fractures were restorable. Conclusion: Full-cusp-coverage restoration or fiber-post-supported restoration could improve the fracture resistance of ETT with cervical defects, whereas unrestorable fractures easily occurred in fiber-post-supported restorations.

Evaluation of apical root defects during canal instrumentation with two different nickel-titanium (NiTi) systems by optical coherence tomography (OCT) scan.

Background/purpose: Canal instrumentation with rotary nickel-titanium (NiTi) instruments might weaken the dentinal wall. This study aims to investigate the apical root defects during canal instrumentation with two NiTi rotary systems by using optical coherence tomography (OCT) scans. Materials and methods: Twenty mandibular incisors were selected and divided into two groups instrumented using HyFlex CM (HCM) and ProTaper Universal (PTU) systems. OCT scans were taken immediately after canal instrumentation with file #25, #30 and #40. Each cross-sectional reconstructed image of 1, 2 and 3 mm from the apex was examined, root cracks were scored, and dentin thickness was measured at 12 sites. The risk sites with dentin thickness less than 0.30 mm were recorded. Results: In HCM group, no cracks were observed after instrumentation with file #30/.06, while in PTU group, root cracks were found in 6 teeth with a total score of 9 after using F3 (#30/.09) (P < 0.05). After file #40, 8 teeth with cracks had a score of 14 in PTU group, while one tooth was observed crack with a score of 1 in HCM group (P < 0.05). The number of risk sites in PTU group was 49 (13.16%), which was significantly more than the 28 (7.78%) in HCM group (P < 0.05) when canals were instrumented with file #30. Conclusion: Within the limitations of this study, when the canals of mandibular incisors were instrumented with size #30 and #40 files, OCT scans showed less root defects in HCM group.

Evolution and development: engine-driven endodontic rotary nickel-titanium instruments.

Various engine-driven NiTi endodontic files have been indispensable and efficient tools in cleaning and shaping of root canals for practitioners. In this review, we introduce the relative terms and conceptions of NiTi file, including crystal phase composition, the design of the cutting part, types of separation. This review also analysis the main improvement and evolution of different generations of engine-driven nickel-titanium instruments in the past 20 years in the geometric design, manufacturing surface treatment such as electropolishing, thermal treatment, metallurgy. And the variety of motion modes of NiTi files to improve resistance to torsional failure were also discussed. Continuous advancements by the designers, provide better balance between shaping efficiency and resistance to of NiTi systems. In clinical practice an appropriate system should be selected based on the anatomy of the root canal, instrument characteristics, and operators' experience.

Microtensile bond strength to sealer-contaminated dentin after using different cleaning protocols.

BACKGROUND/PURPOSE: Sealer residues on dentin may affect bonding to restorative materials. This study aimed to evaluate the bond strength to sealer-contaminated dentin after using different cleaning protocols. MATERIALS AND METHODS: Freshly extracted bovine incisors were prepared and exposed the buccal pulp chamber dentin, obtaining segments measuring 5 mm × 5 mm with a height of 3 mm. The segments were randomly distributed into 4 groups (n = 7) according to different protocols. Control group: no contamination was performed. In the three experimental groups, the segments were contaminated with epoxy resin-based sealer for 5 min, and different cleaning protocols were performed. Acetone group: acetone-saturated cotton pellets were used to wipe the sealer. Ultrasound group: ultrasonic ET-20D tip cleaning. Acetone combined with ultrasound group: cleaning with acetone-saturated cotton pellets and ultrasonic tip. All segments were bonded using a self-etch adhesive. Two samples in each group were scanned by swept-source optical coherence tomography (SS-OCT) to evaluate sealer residues. A microtensile test was performed on the remaining 5 samples, which were built up with composite resin. RESULTS: Sealer residues were observed in 3 of 14 (21.4%) sections of acetone group by SS-OCT. Compared to the control, ultrasound alone or in combination with acetone preserved the bond strength (P > .05). The ultrasound group exhibited the highest bond strength (39.38 MPa), which differed from that of the acetone group, which provided the lowest bond strength (32.88 MPa) (P < .05). CONCLUSION: Cleaning epoxy resin-based sealer-contaminated dentin surfaces using ultrasound or combined with acetone could preserve the bond strength.

GDPLichi: a DNA Damage Repair-Related Gene Classifier for Predicting Lung Adenocarcinoma Immune Checkpoint Inhibitors Response.

Lung cancer is one of the most common and mortal malignancies, usually with a poor prognosis in its advanced or recurrent stages. Recently, immune checkpoint inhibitors (ICIs) immunotherapy has revolutionized the treatment of human cancers including lung adenocarcinoma (LUAD), and significantly improved patients' prognoses. However, the prognostic and predictive outcomes differ because of tumor heterogeneity. Here, we present an effective method, GDPLichi (Genes of DNA damage repair to predict LUAD immune checkpoint inhibitors response), as the signature to predict the LUAD patient's response to the ICIs. GDPLichi utilized only 7 maker genes from 8 DDR pathways to construct the predictive model and classified LUAD patients into two subgroups: low- and high-risk groups. The high-risk group was featured by worse prognosis and decreased B cells, CD8+ T cells, CD8+ central memory T cells, hematopoietic stem cells (HSC), myeloid dendritic cells (MDC), and immune scores as compared to the low-risk group. However, our research also suggests that the high-risk group was more sensitive to ICIs, which might be explained by increased TMB, neoantigen, immune checkpoint molecules, and immune suppression genes' expression, but lower TIDE score as compared to the low-risk group. This conclusion was verified in three other LUAD cohort datasets (GSE30219, GSE31210, GSE50081).

Accuracy of root-end resection using a digital guide in endodontic surgery: An in vitro study.

BACKGROUND/PURPOSE: It is difficult to achieve accurate root-end resection clinically. This in vitro study was conducted to evaluate the operation accuracy of a digital endodontic surgical guide. MATERIALS AND METHODS: 56 extracted maxillary anterior teeth were prepared for endodontic surgical models. The models were randomly divided into 4 groups equally according to the guide (with guide/no guide) and the operator (experienced/inexperienced). Endodontic microsurgeries were performed on models in each group. The deviations in length and angle of the root-end resection were measured based on the optical scanning data of the pre- and postoperative teeth. The general linear model was performed to analyze the effect of a guide on root-end resection deviation. RESULTS: Using a guide, the mean length deviation for experienced/inexperienced operators reduced from 0.99 mm (95% CI [confidence interval, CI], 0.66-1.33 mm)/1.18 mm (95% CI, 0.50-1.86 mm) to 0.31 mm (95% CI, 0.20-0.42 mm)/0.31 mm (95% CI, 0.24-0.37 mm). The mean angle deviation for experienced/inexperienced operators reduced from 16.74° (95% CI, 10.61-22.86°)/15.06° (95% CI, 9.19-20.94°) to 5.04° (95% CI, 3.31-6.77°)/6.79° (95% CI, 4.91-8.67°). The difference was significant between procedures performed with and without a guide (P < 0.01). CONCLUSION: Application of the digital guide in vitro endodontic surgery could improve the accuracy of root-end resection.