Comparisons of student comprehension of 3D-printed, standard model, and extracted teeth in hands-on sessions

INTRODUCTION

Cavity preparation and direct and indirect pulp capping are difficult processes to learn in dentistry. Although plastic teeth are used in universities in Turkey, the standard model does not teach students how to distinguish between dental hard tissues from caries and how this relates to the pulp. The aim of this study was to investigate the differences in learning when a three-dimensional (3D)-printed tooth was employed in comparison with the standard model and extracted teeth. The differences are evaluated in the design, feasibility, and contribution of the 3D-printed dental tooth in pre-clinical education.

MATERIALS AND METHODS

The multi-layer 3D-printed tooth's authentic design and replication of the dental hard tissues and carious lesions are explored with 55 students for pre-clinical education, which includes caries excavation and direct and indirect pulp capping. The students completed questionnaires evaluating the 3D-printed teeth through comparison with the plastic and extracted teeth, rated with scores from 1 to 11 (1: poorest conformity; 11: excellent conformity).

RESULTS

The questionnaire results indicated that students approved the printed tooth model for the practice of theoretical knowledge and the model received ratings between good and excellent. The results were statistically analysed using the Wilcoxon signed-rank test, and the printed teeth had the highest approval from the students (p < .001).

CONCLUSION

The results of this study demonstrated that the use of the designed 3D-printed tooth is preferred by the students based on their perception of learning cavity preparation and pulp capping in a pre-clinical environment. Workflow and production were cost-effective with the use of 3D printing technology. The printed tooth allowed students to gain realistic experience before treating patients.

Comparison of discoloration of ceramic containing 3D printable material and CAD/CAM blocks

This study aimed to clarify aspects of the color and translucency of 3D printed dental material with CAD/CAM blocks. Three different ceramic-containing, resin-based CAD/CAM blocks and a 3D printable resin were evaluated after thermocycled and assessed for their degree of discoloration based on colorant types and storage times. Data were analyzed using repeated-measures analysis of variance followed by Tukey's post-hoc test. All materials in red wine had ∆E00 values higher than the clinically accepted threshold value. At 1 week and 1 month, the 3D material was statistically significantly more discolored than the other 3 materials (p<0.05). None of the materials exceeded the acceptable threshold value at any time point. The color changes increased over time in resin-based CAD/CAM blocks and 3D printable dental materials. After 1 week and 1 month, there was a statistically significant difference in the color change between the 3D printed material and the CAD/CAM blocks.

Do Atmospheric Changes and the Synodic Lunar Cycle Affect the Development of Spontaneous Pneumothorax?

BACKGROUND

Pneumothorax is defined as air in pleural space. The etiology of spontaneous pneumothorax (SP) is still under investigation and, despite many studies, remains uncertain. The aim of this study was to investigate the effects of the lunar cycle and daily weather changes on SP development.

METHODS

The data of patients admitted to our clinic with SP were analysed retrospectively. The daily atmospheric pressure, relative ratio of humidity and temperature in degrees Celsius of each day were obtained. The mean values for each day, from the first to the 29th day, of the synodic lunar cycle (SLC) were calculated for the five-year study period. The attacks were allocated to the appropriate day of an ideal 29-day SLC, irrespective of the calendar date.

RESULTS

A total of 131 patients who were admitted to our hospital with SP (130 males and 1 female with an average age of 32.4±12.2) were included in this study. The number of patients with SP showed a statistically significant correlation with mean atmospheric pressure (p=0.005), relative humidity (p=0.007) and outdoor temperature (p=0.02) but not with the SLC.

CONCLUSIONS

SP is significantly influenced by weather-related factors. Changes in atmospheric pressure, humidity and outdoor temperature had obvious effects on the development of SP. However, the SLC had no effect on SP.

Neuroprotection by alpha-lipoic acid in streptozotocin-induced diabetes

Glial cells provide structural and metabolic support for neurons, and these cells become reactive to any insult to the central nervous system. The streptozotocin (STZ) rat model was used to study glial reactivity and the prevention of gliosis by alpha-lipoic acid (alpha-LA) administration. The expression of glial fibrillary acidic protein (GFAP), S100B protein, and neuron specific enolase (NSE) was determined as well as lipid peroxidation (LPO) and glutathione (GSH) levels in some brain tissues. Western blot analyses showed GFAP, S100B, and NSE levels significantly increased under STZ-induced diabetes in brain, and LPO level increased as well. Administration of alpha-LA reduced the expression both of glial and neuronal markers. In addition, alpha-LA significantly prevented the increase in LPO levels found in diabetic rats. GSH levels were increased by the administration of alpha-LA. This study suggests that alpha-LA prevents neural injury by inhibiting oxidative stress and suppressing reactive gliosis.