D2 Thresholds Research Articles

A new group of doubly charmed molecule with T-doublet charmed meson pair

Inspired by the observation of the doubly charmed tetraquark state Tcc+ at the LHCb Collaboration, we systematically study the S-wave interactions between a pair of charmed mesons (D1,D2⁎) in the T-doublet, where we adopt the one-boson-exchange model and consider both the S-D wave mixing and coupled channel effects. Our numerical results suggest that the prime doubly charmed molecular tetraquark candidates are the S-wave D1D1 state with I(JP)=0(1+), the S-wave D1D2⁎ states with I(JP)=0(1+,2+,3+), and the S-wave D2⁎D2⁎ states with I(JP)=0(1+,3+). The S-wave D1D1 state with I(JP)=1(2+), the S-wave D1D2⁎ state with I(JP)=1(3+), and the S-wave D2⁎D2⁎ state with I(JP)=1(4+) may be the possible isovector doubly charmed molecular tetraquark candidates. We expect the experiments like the LHCb or Belle II collaborations to search for these predicted doubly charmed molecular tetraquarks near the D1D1, D1D2⁎, and D2⁎D2⁎ thresholds in the future.

Validity of near-infrared light transillumination for the assessment of proximal caries in permanent teeth.

The aim of this study was to evaluate the performance of DIAGNOcam (DC) in diagnosing proximal caries and to compare its effectiveness with the International Caries Detection and Assessment System (ICDAS) and bitewing radiography (BWR). 118 premolars extracted for orthodontic reasons were included and examined using three detection methods and validated by histological sections as the gold standard. The sensitivity, specificity and areas under the ROC curve (Az value) at the outer half enamel (D1), inner half enamel (D2) and dentine (D3) thresholds were compared between different methods. At all categories, the specificity of DC was almost as high as ICDAS and BWR. DC showed a significantly higher sensitivity (0.68) than both visual (0.33) and radiographic examination (0.47) at the D1 threshold. DC presented the highest Az value (area under the ROC curve) at the D1 and D2 threshold (0.81, 0.86), while BWR showed the greatest Az values at D3 (0.94). Furthermore, DC had the highest association strength with the gold standard (Spearman's ρ = 0.80). It can be concluded that DC could detect proximal caries effectively and showed comparable or even better performance than ICDAS and BWR.

In Vivo Comparative Enactment of CarieScanPRO™ with Conventional Methods to Detect Occlusal Carious Lesions in the Mandibular Primary Molars.

ABSTRACTAimTo assess the performance of CarieScanPRO™ with radiovisiography (RVG) and international caries detection and assessment system II (ICDAS-II) to detect the occlusal carious lesions in the mandibular primary molars.MethodsFifty healthy children of age 5–7 years were involved and evaluated for caries using visual ICDAS-II, RVG, and CarieScanPRO™. Operative intervention pit and fissure opening served as a gold standard for comparison of the three methods of examination. The sensitivity, specificity, accuracy, and area under the receiver operating characteristic (ROC) curve (Az) of the methods were calculated at enamel (D1), dentinoenamel junction (DEJ) (D2), and dentine (D3, D4).ResultsAt D1 threshold, CarieScanPRO™ showed higher values of sensitivity and accuracy (0.97 and 0.88) and RVG specificity (0.92). At D2 threshold, visual examination showed higher values of sensitivity (0.80) whereas CarieScanPRO™ showed specificity and accuracy of 0.98 and 0.87. At D3, D4 threshold, CarieScanPRO™ showed higher values of sensitivity, specificity, and accuracy (0.1, 0.98, and 0.99). Higher positive predictive value (PPV), negative predictive value (NPV) and lower false discovery rate (FDR), false-positive rate (FPR) were shown by CarieScanPRO™. The intraexaminer repeatability for CarieScanPRO™ was good with kappa at D1 (0.77) and D3, D4 (0.98).ConclusionCarieScanPRO™ showed higher reproducibility compared to visual examination and RVG for the detection of enamel and dentinal caries. Higher accuracy of CarieScanPRO™ can be used for longitudinal monitoring of occlusal caries in primary teeth with low sensitivity at DEJ.How to cite this articlePopuri VD, Nirmala SVSG, et al. In Vivo Comparative Enactment of CarieScanPRO™ with Conventional Methods to Detect Occlusal Carious Lesions in the Mandibular Primary Molars. Int J Clin Pediatr Dent 2019;12(4):325–331.

Dental Students' Performance in Detecting In Vitro Occlusal Carious Lesions Using ICDAS with E-Learning and Digital Learning Strategies.

The aim of this study was to assess the performance of dental students for detecting in vitro occlusal carious lesions using the International Caries Detection and Assessment System (ICDAS) with different learning strategies. A convenience sample of all 64 fourth-year dental students at a dental school in Brazil who had no previous experience with ICDAS was selected for the study in 2015. First, students performed the in vitro examination of the occlusal surfaces of 80 teeth according to ICDAS. Two weeks later, students were randomly allocated to three groups: G1 (n=21), ICDAS e-learning; G2 (n=22), ICDAS e-learning + digital learning tool (DLT); G3 (n=21), no training (control group). All students reexamined the 80 teeth according to ICDAS two weeks later. Sensitivity, specificity, and area under the ROC curve (AUC) were calculated according to three thresholds. Of the 64 students, 59 completed all study phases, for a 92.2% participation rate. The intra-group comparison found significantly higher sensitivity and specificity values for G1 and G2 students. G3 students showed an increased sensitivity at the D2 threshold. G2 was the only training strategy that resulted in significant improvement for the AUC. In the comparison of groups at the same threshold, G1 showed higher specificity at D3 threshold (0.78) than G2 (0.72) and G3 (0.73). Regarding sensitivity, G1 showed a lower value at D2 (0.91) threshold than G2 (0.94) and G3 (0.94). In this study, both training strategies (ICDAS e-learning and ICDAS e-learning + DLT) improved the performance of dental students for the in vitro detection of occlusal carious lesions, mainly when the association of methods was used.

Comparison of laser fluorescence devices for detection of caries in primary teeth

The aim of this in vivo study was to evaluate the performance of fluorescence-based devices in detecting occlusal caries lesions in primary molars compared with conventional methods. Two examiners assessed 44 occlusal surfaces of first and second primary molars in 20 patients using two fluorescence devices: DIAGNOdent (LF) and DIAGNOdent pen (LFpen). Teeth were also assessed by visual examination and bitewing radiograph. Histological examination served as the gold standard after extraction. By using the McNemar test, the sensitivity, specificity, accuracy, and area under the receiver operating curve were calculated as outer enamel (D1), inner enamel (D2) and dentine caries (D3) lesion thresholds. The intra- and inter-examiner reproducibility were calculated using the Cohen's unweighted kappa statistics. At the D1 threshold, the LFpen sensitivity was statistically higher than LF and radiographic examination (P < 0.001), whereas there was no statistically significant difference among the groups at the D2 and D3 thresholds (P > 0.05). All methods demonstrated the highest sensitivity values at D3. At the D1 and D2 thresholds, there were no significant differences between the LFpen specificity and the other methods. All methods presented similar performance in detecting all lesions considering the area under the receiver operating curve. The LFpen showed better performance than LF. Furthermore, visual examination and the LFpen device seem to be sufficient for detection of occlusal caries in primary molars.

Clinical Performance of Two Visual Scoring Systems in Detecting and Assessing Activity Status of Occlusal Caries in Primary Teeth

This study aimed to compare the clinical performance of two sets of visual scoring criteria for detecting caries severity and assessing caries activity status in occlusal surfaces. Two visual scoring systems – the Nyvad criteria (NY) and the ICDAS-II including an adjunct system for lesion activity assessment (ICDAS-LAA) – were compared using 763 primary molars of 139 children aged 3–12 years. The examinations were performed by 2 calibrated examiners. A subsample (n = 50) was collected after extraction and histology with 0.1% red methyl dye was performed to validate lesion depth and activity. The reproducibility of the indices was calculated (kappa test) and ROC analysis was performed to assess their validity and related parameters were compared using McNemar’s test. The association between the indices and with the histological examination was evaluated using Spearman’s correlation coefficient (r_s). Visual criteria showed excellent reproducibility both regarding severity (NY: 0.94; ICDAS-II: 0.91) and activity (NY: 0.90; LAA: 0.91). The NY and LAA showed good association in caries activity assessment (r_s = 0.88; 95% CI = 0.86–0.89; p < 0.001). Nevertheless, considering only cavitated lesions, this association was not significant (p > 0.05). Concerning the severity, both indices presented similar validity parameters. At D2 threshold, the sensitivity was higher for NY (NY = 0.87; ICDAS = 0.61, p < 0.05). Regarding activity status, NY showed higher specificities and accuracies. In conclusion, NY and ICDAS-II criteria are comparable and present good reproducibility and validity to detect caries lesions and estimate their severities, but the LAA seems to overestimate the caries activity assessment of cavitated lesions compared to NY.

Assessment of double-burst monitoring at 10 mA above threshold current

We compared fade measurements in response to double-burst stimulation (DBS) at 10 mA above the threshold for the second response (D2) to that for DBS at 60 mA in order to determine the utility of low-current DBS testing. In 20 healthy adults undergoing general endotracheal anesthesia with isoflurane 0.5-1% end-tidal, a vecuronium infusion (0.25-1.5 micrograms.kg-1 x min-1) was delivered until a stable train-of-four (TOF) response to ulnar nerve stimulation was documented with an adductor pollicis force transducer. Then DBS responses were recorded, and the D2/D1 ratios were determined at 60 mA and at 10 mA above the D2 threshold current (TS + 10 mA). The mean difference (bias) between D2/D1 /TS+10 mA and D2/D1 / 60 mA was -0.02 (P < 0.05); the 95% limits of agreement were from -0.12 to +0.08. The bias and limits of agreement were similar to those for T4/T1 of train-of-four. A strong correlation was noted between the degrees of fade determined at the low and high currents (r = 0.95). We conclude that, although stimulation at 10 mA above the D2 threshold is associated with a slight negative bias, it is virtually interchangeable with testing at higher current in the clinical setting. This technique thus may be used effectively to monitor neuromuscular fade in settings where neurostimulation with low current is deemed desirable.