Micro-CT assessment of radicular pulp calcifications in extracted maxillary first molar teeth

Analysis of obtaining apical patency indexes during endodontic treatments considering gender, age, pulpoperiradicular diagnosis and canal/tooth-A clinical study

This study aimed to perform an analysis of obtaining apical patency indexes during endodontic treatments considering gender, age, pulpoperiradicular diagnosis and canal/tooth (n. 639/383). Following previous clinical procedures, a thin K-File (No. 20, 15, 10 or 08) was used to achieve apical patency. These specific data and some demographic and clinical information were submitted to the statistical analysis (p < 0.05). Significant statistical differences were not identified considering gender (p = 0.156) and age (p = 0.793). However, in 14.6% of the canals of vital teeth and 14.1% of the canals of necrotic teeth without periapical lesions, apical patency could not be achieved, which occurred in only 7% of the canals of necrotic teeth with periradicular disease (p = 0.009). Considering canal/tooth, apical patency was more challenging to obtain in canals of posterior teeth (p = 0.000). The pulpoperiapical diagnosis and canal/tooth significantly influenced the obtaining of apical patency.

The investigation of WNT6 and WNT10A single nucleotide polymorphisms as potential biomarkers for dental pulp calcification in orthodontic patients

The aim of this study is to evaluate if single nucleotide polymorphisms (SNPs) in WNT6 and WNT10A are associated with the risk of dental pulp calcification in orthodontic patients. This cross-sectional study followed the "Strengthening the Reporting of Genetic Association Studies" (STREGA) guidelines. Panoramic radiographs (pre- and post-orthodontic treatment) and genomic DNA from 132 orthodontic patients were studied. Dental pulp calcification (pulp stones and/or pulp space narrowing) was recorded in upper and lower first molars. The SNPs in WNT6 and WNT10A (rs7349332, rs3806557, rs10177996, and rs6754599) were assessed through genotyping analysis using DNA extracted from buccal epithelial cells. The association between pulp calcification and SNPs were analyzed using allelic and genotypic distributions and haplotype frequencies (p<0.05). Prevalence of dental pulp calcification was 42.4% in the 490 studied molars. In the genotypic analysis, the SNPs in WNT10A showed a statistically significant value for molar calcification (p = 0.027 for rs1017799), upper molar calcification (p = 0.040 for rs1017799) (recessive model), and molar calcification (p = 0.046 for rs3806557) (recessive model). In the allelic distribution, the allele C of the SNP rs10177996 in WNT10A was associated with molar calcifications (p = 0.042) and with upper first molar calcification (p = 0.035). Nine combinations of haplotypes showed statistically significant value (p<0.05). The findings of this study indicates that SNPs in WNT10A and WNT6 are associated with dental pulp calcification in molars after orthodontic treatment and may be considered as biomarkers for dental pulp calcification.

Age-related changes in the morphology of the root canal system of mandibular first molars: a micro-CT study

OBJECTIVE

This study aimed to evaluate changes on root canal morphology in patients with different ages using micro-CT technology.

MATERIALS AND METHODS

Mandibular first molars (n = 150) were scanned at a pixel size of 13.68 µm, categorized into 3 groups according to patient's age and analyzed regarding configuration, orifices, apical foramina, root length, canal volume, and surface area. Morphological 2D and 3D parameters were evaluated in distal roots with Type I configuration (n = 109) as well as the morphology of isthmuses Types I and III in 68 mesial roots. One-way ANOVA post hoc Tukey and Kruskal-Wallis tests were used for statistical analyses (α = 5%).

RESULTS

A great variation in the canal configuration was found. No difference was observed in roots' length (p > 0.05). Canal volume reduced with age (p < 0.05), while surface area increased (p < 0.05) in patients ≤ 30 years. There was no difference in canal/root length, area, and from foramen to the apex in distal roots with Type I configuration (p > 0.05), but 2D and 3D parameters significantly decreased with age (p < 0.05). Overall, the diameter of the isthmuses' roof reduced with age (p < 0.05). In patients ≥ 31 years with Type III isthmus the distance from the isthmus floor to the foramen of the mesiolingual canal also decreased (p < 0.05).

CONCLUSION

Overall, the internal morphology of the mesial roots of mandibular first molars was more affected by aging than distal canals. The most relevant tested parameter that significantly reduced in both roots was the volume of the root canal systems.

CLINICAL RELEVANCE

A detailed evaluation of fine anatomical aspects of the root canal system of mandibular first molars of patients with different ages showed that the internal morphology of mesial roots is more affected by aging than distal canals.

Detection of pulpal calcifications on bite-wing radiographs using deep learning

OBJECTIVES

Pulpal calcifications are discrete hard calcified masses of varying sizes in the dental pulp cavity. This study is aimed at measuring the performance of the YOLOv4 deep learning algorithm to automatically determine whether there is calcification in the pulp chambers in bite-wing radiographs.

MATERIALS AND METHODS

In this study, 2000 bite-wing radiographs were collected from the faculty database. The oral radiologists labeled the pulp chambers on the radiographs as "Present" and "Absent" according to whether there was calcification. The data were randomly divided into 80% training, 10% validation, and 10% testing. The weight file for pulpal calcification was obtained by training the YOLOv4 algorithm with the transfer learning method. Using the weights obtained, pulp chambers and calcifications were automatically detected on the test radiographs that the algorithm had never seen. Two oral radiologists evaluated the test results, and performance criteria were calculated.

RESULTS

The results obtained on the test data were evaluated in two stages: detection of pulp chambers and detection of pulpal calcification. The detection performance of pulp chambers was as follows: recall 86.98%, precision 98.94%, F1-score 91.60%, and accuracy 86.18%. Pulpal calcification "Absent" and "Present" detection performance was as follows: recall 86.39%, precision 85.23%, specificity 97.94%, F1-score 85.49%, and accuracy 96.54%.

CONCLUSION

The YOLOv4 algorithm trained with bite-wing radiographs detected pulp chambers and calcification with high success rates.

CLINICAL RELEVANCE

Automatic detection of pulpal calcifications with deep learning will be used in clinical practice as a decision support system with high accuracy rates in diagnosing dentists.

Irrigant flow characteristics in the root canal with internal root resorption: a computational fluid dynamics evaluation

Irrigation dynamics of syringe irrigation with different needle designs (side-vented, double side-vented, notched) and ultrasonic irrigation in the root canal with internal root resorption were evaluated using a computational fluid dynamics model. A micro-CT scanned mandibular premolar was used for modeling internal root resorption. The needles and the ultrasonic tip were positioned at 2, 4, and 5 mm from the working length. The insertion depth and the irrigation model were found influential on the shear stress and the irrigant extension. The extension of the irrigant increased toward 2-5 mm from the working length. Ultrasonic irrigation revealed the highest shear stress values regardless of the insertion depth. The shear stress distribution on the resorption cavity walls gradually increased when the needles were positioned coronally. The residence time of the irrigant in the canal was affected by the needle position relative to the internal root resorption cavity and the needle type.