Cephalometric landmark identification consistency between undergraduate dental students and orthodontic residents in 3-dimensional rendered cone-beam computed tomography images: A preliminary study.

INTRODUCTION: The aim of this study was to compare 3-dimensional landmark consistency and precision in skeletal structures in groups with different levels of experience with 2-dimensional cephalometrics. METHODS: Sixteen observers, all undergraduate or graduate students, were divided into 4 groups with different levels of experience in 2-dimensional landmarking and no previous experience in 3 dimensions. Group 1 consisted of 4 third-year dental students with no experience in cephalometric landmarking. Groups 2, 3, and 4 consisted of first-, second-, and third-year graduate students, with increasing levels of experience. The participants located 18 landmarks in 12 surface models of cone-beam computed tomography scans of patients on 3 separate occasions. The average of all examiners locating each landmark was defined as the centroid. The mean of the distances of each located point to the centroid of that landmark was used as the mean consistency (MC), and the standard deviation (SD) was used as the precision. Analysis of variance and post hoc Tukey comparisons between groups were done. RESULTS: The MC and SD values across landmarks, patients, and examiners were 1.03 ± 1.14 mm. The MC and SD were 0.89 ± 0.83 mm for group 1 with no experience, 1.02 ± 0.95 mm for group 2, 1.17 ± 1.60 mm for group 3, and 1.05 ± 1.00 mm for group 4. Significant differences were found among the groups. CONCLUSIONS: Comparing the observer groups studied, the undergraduate dental school students without previous experience in bidimensional cephalometrics obtained the best values in volumetric landmark location. Graduate students with increasing amounts of experience did not perform as well. These results and conclusions should be interpreted with caution because the number of subjects in each group was small.

Visual perception of skeletal class and biotype in Spain.

The aim of this study was to determine and compare the visual accuracy of students and experienced orthodontists in distinguishing the different skeletal classes and facial biotypes using only lateral photographs. A group of 19 orthodontic students (4 males and 15 females, aged between 23 and 30 years) and 9 experienced orthodontists (three males and six females, aged between 30 and 56 years) were shown a slide presentation of 100 (50 males and 50 females) patients aged between 8 and 42 years and were asked to indicate the skeletal class and the facial biotype of each subject. Data were analysed using a one-way repeated measures analysis of variance, with Bonferroni post hoc adjustment for multiple testing. P-values less than 0.05 were considered statistically significant. Only 32.75 per cent of the participants identified the facial biotype of the patients with respect to Rickett's vertical (Vert) pattern and 47.96 per cent the skeletal class. The students performed better than the experienced orthodontists (P < 0.05) but only for skeletal class. The results indicate that lateral photographs are not sufficient for determining the skeletal class or facial biotype of patients.

Shear bond strength of a flash-free orthodontic adhesive system after thermal aging procedure.

In this article by Carlos and colleagues (J Clin Exp Dent. 2019 Feb 1;11(2):e154-61), there is an error in the Material and Methods of the abstract. The correct Material and Methods of the abstract is: Material and Methods: A total of 120 human premolars were randomly divided into two groups (n=60) according to the orthodontic adhesive used: APC Flash-Free Adhesive Coated Appliance System (APC FF) or Transbond PLUS Color Change Adhesive (TP), as control. A SBS test was performed and ARI value for each specimen was also assessed. Results were analyzed by two-way ANOVA and Tukey's Chi-square test (p<0.05).

Shear bond strength of a flash-free orthodontic adhesive system after thermal aging procedure.

BACKGROUND: The aim of this study was to compare the shear bond strength (SBS) of a flash-free and precoated orthodontic adhesive with a compomer orthodontic adhesive before and after thermocycling. The adhesive remnant index (ARI) was also determined for both adhesives. MATERIAL AND METHODS: The adhesive remnant index (ARI) was also determined for both adhesives. Material and Methods: A total of 120 human premolars were randomly divided into two groups (n=60) according to the orthodontic adhesive used: APC Flash-Free Adhesive Coated Appliance System (APC FF) or Transbond PLUS Color Change Adhesive (TP), as control. A SBS test was performed and ARI value for each specimen was also assessed. Results were analyzed by two-way ANOVA and Tukey's Chi-square test (p<0.05). RESULTS: SBS values were significantly influenced by thermocycling (p<0.01). Neither the orthodontic adhesive nor the interaction between adhesive and thermocycling statistically affected SBS results (p>0.05). CONCLUSIONS: APC FF and TP showed similar bond strength results. Thermocycling induced a significant decrease in SBS values for the two adhesives tested, without differences between 10,000 and 20,000 thermal cycles. Moreover, APC FF left less adhesive remnants on the enamel compared to TP. Key words:APC Flash-Free, APC cement, aging, orthodontics, resin cements.