Root canal morphology of primary maxillary second molars:a micro-computed tomography analysis

Aim Successful endodontic treatment of primary teeth requires comprehensive knowledge and understanding of root canal morphology. The purpose of this study was to investigate the root canal configurations of primary maxillary second molars using micro-computed tomography. Methods Extracted human primary maxillary second molars (n = 57) were scanned using micro-computed tomography and reconstructed to produce three-dimensional models. Each root canal system was analysed qualitatively according to Vertucci's classification. Results 22.8% (n = 13) of the sample presented with the fusion of the disto-buccal and palatal roots; of these, Type V was the most prevalent classification. For teeth with three separate roots (n = 44), the most common root canal type was Type 1 for the palatal canal (100%) and disto-buccal canal (77.3%) and Type V for the mesio-buccal canal (36.4%). Overall, 7% (n = 4) of mesio-buccal canals were 'unclassifiable'. Conclusion The root canal systems of primary maxillary second molars were not only complex but had a range of configurations that may contribute to unfavourable clinical outcomes after endodontic treatment

Binarized Support Vector Machines

The widely used support vector machine (SVM) method has shown to yield very good results in supervised classification problems. Other methods such as classification trees have become more popular among practitioners than SVM thanks to their interpretability, which is an important issue in data mining. In this work, we propose an SVM-based method that automatically detects the most important predictor variables and the role they play in the classifier. In particular, the proposed method is able to detect those values and intervals that are critical for the classification. The method involves the optimization of a linear programming problem in the spirit of the Lasso method with a large number of decision variables. The numerical experience reported shows that a rather direct use of the standard column generation strategy leads to a classification method that, in terms of classification ability, is competitive against the standard linear SVM and classification trees. Moreover, the proposed method is robust; i.e., it is stable in the presence of outliers and invariant to change of scale or measurement units of the predictor variables. When the complexity of the classifier is an important issue, a wrapper feature selection method is applied, yielding simpler but still competitive classifiers

Evaluation of root canal morphology of human primary mandibular second molars by using cone beam computed tomography

Objectives: The aim of the present study was to investigate the root canal configurations of primary mandibular second molars (PMSMs) using Vertucci classification. Materials and Methods: The root canal types of 228 PMSMs (228 mesial and 228 distal roots) were evaluated. In addition, the relationship between external root morphology and Vertucci classification was investigated. The Chi‑square test or Fisher Exact Chi‑square test was used for the evaluations, and P < 0.05 was considered statistically significant for all tests. Results: The most commonly observed root canal type, which was observed in 228 roots (50%), was Type 4 followed by Type 8 (15.79%), Type 5 (14.47%), Type 1 (9.21%), and Type 3 (6.57%). In 150 mesial roots, the root canal Type 4 was observed whereas the same type was observed in 78 distal roots, and the difference was significant (P < 0.001). In flat roots (82.9%), the most frequently observed root canal type was Type 4 (50.8%) (P < 0.001).Conclusion: Various root canal types were observed in both mesial and distal roots although Type 4 was the most commonly observed. Root canal types showed a  consistent relationship with separated and conical root shapes whereas the flat roots showed different root canal types.Keywords: Primary teeth, root canal, Vertucci classificatio

Evaluation of root canal morphology of human primary mandibular second molars by using cone beam computed tomography

Objectives: The aim of the present study was to investigate the root canal configurations of primary mandibular second molars (PMSMs) using Vertucci classification. Materials and Methods: The root canal types of 228 PMSMs (228 mesial and 228 distal roots) were evaluated. In addition, the relationship between external root morphology and Vertucci classification was investigated. The Chi-square test or Fisher Exact Chi-square test was used for the evaluations, and P < 0.05 was considered statistically significant for all tests. Results: The most commonly observed root canal type, which was observed in 228 roots (50%), was Type 4 followed by Type 8 (15.79%), Type 5 (14.47%), Type 1 (9.21%), and Type 3 (6.57%). In 150 mesial roots, the root canal Type 4 was observed whereas the same type was observed in 78 distal roots, and the difference was significant (P < 0.001). In flat roots (82.9%), the most frequently observed root canal type was Type 4 (50.8%) (P < 0.001). Conclusion: Various root canal types were observed in both mesial and distal roots although Type 4 was the most commonly observed. Root canal types showed a consistent relationship with separated and conical root shapes whereas the flat roots showed different root canal types. © 2018 Medknow Publications. All rights reserved

Compact operators on the Jordan totient sequence spaces

The necessary and sufficient conditions for compactness of a matrix operator between Banach spaces is obtained by utilizing the concept of the Hausdorff measure of noncompactness. This is one of the most interesting application in the theory of sequence spaces. In this paper, the compact operators are characterized on Jordan totient sequence spaces by using the concept of the Hausdorff measure of noncompactness.WOS:0005358235000012-s2.0-8508556958