Statistical evaluation of the learning curve in digital impression in different types of operators

Aim The objective of this study was to evaluate the learning curve associated with intraoral scanning using the CEREC system, comparing two groups: dental students and experienced clinicians. The study aimed to assess improvements in time, surface area acquired, and surface-time ratio (X) to determine the efficiency of repeated scanning.

Materials and Methods A total of 50 participants were recruited for the study, divided into two groups: 25 dental students from the San Raffaele Faculty of Dentistry and 25 clinicians with at least 5 years of experience. Each participant performed four intraoral scans on a plaster model using the CEREC intraoral scanner. The scans were evaluated for time (T1-T4) in minutes, surface area (SUP) in pixel units, and surface-time ratio (X) as an efficiency metric. Statistical analysis was conducted using IBM SPSS Statistics (version 25) and MeshLab 2016 to assess the learning curve and compare the two groups.

Results Both groups demonstrated a clear learning curve with significant improvements in time and surface-time ratio (X) over the four trials. For clinicians, the average time decreased from 1.399 minutes in T1 to 1.015 minutes in T4, while the surface-time ratio improved from 347.91 mm²/min to 447.77 mm²/min. Students showed a similar reduction in time, from 1.292 minutes in T1 to 1.001 minutes in T4, and an improvement in surface-time ratio from 343.96 mm²/min to 433.12 mm²/min. Clinicians consistently acquired more surface area than students, despite similar scan times, indicating that clinical experience plays a crucial role in scan accuracy.

Conclusion The study highlights the importance of clinical experience in achieving more efficient and complete scans using intraoral scanners. Both groups improved with repetition, but clinicians demonstrated superior performance in terms of surface area acquired. The learning curve plateaued after the third trial, suggesting that sustained practice is necessary for mastery. Future training programs should focus on enhancing both technical proficiency and clinical judgment to optimize the use of digital scanning technology in dentistry.