Learning Curve Analysis of Preclinical All-Ceramic Crown Preparation Among Second-Year Undergraduate Dental Students

Abstract

Mastering complex preclinical skills, such as full-coverage crown preparation, is fundamental in dental education. However, reliable data on the learning progression associated with specific procedures remains limited. This prospective cohort study aimed to evaluate the learning curve for preparing maxillary central incisors for all-ceramic crowns among second-year undergraduate dental students, assess the effectiveness of repeated practice, and estimate the training volume required to achieve clinical competency. Fourteen students performed four weekly crown preparation attempts on tooth #11 of a typodont, following standardized instructions. Preparation time was recorded for each attempt, and three calibrated external examiners assessed the preparations using a validated 15-domain rubric (maximum score: 100). The rubric demonstrated strong internal consistency (Cronbach's α = 0.86) and acceptable inter-rater reliability (ICC = 0.66, p < 0.001). ANOVA and regression analyses were used to model skill development (score) and efficiency (time) over successive attempts. Results revealed a general upward trend in preparation scores from Attempt 1 (mean = 44.52) to Attempt 4 (mean = 47.10), with a transient decline at the second attempt, characteristic of a non-linear early learning phase. Predictive modeling suggested that students require approximately eight practice attempts to attain the proficiency level expected for clinical performance. By the eighth attempt, preparation time improved significantly, decreasing to an average of roughly 600 to 660 seconds (equivalent to 10 - 11 minutes). These findings offer quantitative insights into the development of preclinical skills in prosthodontics and support the integration of sufficient repetition within preclinical curricula to ensure competency-based training outcomes.