[Application of animal models in gingival retraction experimental curriculum]

To introduce a teaching method for gingival retraction, and evaluate its efficacy for implementation into experimental curricula.

First, two kinds of animal models using pigs and cows (below 6 months of age) were established. Twenty-two experienced prosthodontists were then asked to apply gingival retraction on each animal model and evaluate the biofidelity of the 2 models' dento-gingival environment. The data was analyzed with SPSS19.0 software package for paired t test.Then, eighty pre-internship students were randomly divided into 2 groups. Besides the traditional teaching (lecture-based teaching), the experimental group (group A) also had access to skill training (using animal models to practice gingival retraction), while the control group (group B) only used the traditional teaching modality. All students' performance in gingival retraction and impression taking were evaluated in their internship. The data was analyzed with SPSS19.0 software package for Chi-square test.

Both pig and cow's dento-gingival environment were similar to that of human being, and there was no significant difference between the two models'biofidelities (P>0.05). In addition, both the effect of gingival retraction and the quality of impression in group A were significantly better than those in group B (P<0.05).

Compared with the traditional strategy,practising gingival retraction on animal models can offer greater opportunities for skill development,and be implemented for a wider range of applications.