Objective:To investigate the application of digital scanning combined with reverse engineering technology in the teaching of full crown preparation.Methods:A total of 30 undergraduate students in the fifth grade of stomatology were selected from Shantou University Medical College and were divided into experimental group and control group using a random number table. Two resin teeth were distributed to each student and were placed on dental head simulators to perform full crown preparation. The students in the control group received teaching with analogies of experience, and those in the experimental group received teaching with digital scanning, i.e., full crown preparation for the second time after digital scanning for the first time of full crown preparation. The score was determined based on China Stomatological Association Standards: Guideline for the tooth preparation of dental ceramic crowns (T/CHSA 008—2023), with a total score of 100 points. SAS9.4 software was used for the two-independent-samples t test and the paired t-test, and the Kendall W concordance coefficient was used to investigate the consistency of evaluators. Results:There were significant changes after teaching in the preparation scores of the right maxillary central incisor (76.27 pre-demonstration vs. 84.70 post-demonstration, P<0.001) and the right maxillary first molar (72.10 pre-demonstration vs. 82.37 post-demonstration, P<0.001). Compared with the control group, the experimental group had a significant increase in the mean preparation score of the right maxillary first molar (14.00 vs. 6.53, t=2.64, P=0.014). In the experimental group, there were significant increases in the preparation scores of the right maxillary first molar for the occlusal surface (15.40 pre-demonstration vs. 19.33 post-demonstration, P<0.001), the buccolingual surface (18.13 pre-demonstration vs. 20.87 post-demonstration, P=0.016), and the proximal surface (12.40 pre-demonstration vs. 14.07 post-demonstration, P=0.004), as well as significant increases in the scores of the convergence angles of the buccolingual surface (2.80 pre-demonstration vs. 4.07 post-demonstration, P=0.004) and the proximal surface (3.47 pre-demonstration vs. 4.47 post-demonstration, P=0.008). Conclusions:Application of digital teaching for difficult crown preparation of posterior teeth can effectively improve the quality of crown preparation among students, standardize the teaching process of crown preparation, and increase the precision of crown preparation, thereby laying a foundation for promoting uniformity in talent cultivation for dental prosthodontics.

Objective : To explore the feasibility of applying the Malocclusion Impact Questionnaire (MIQ) of Chinese version among Chinese teenagers, through the verification and evaluation of the Chinese version. Methods: According to the standard procedures of the international quality of life assessment program, the MIQ was translated, back translated, adapted and updated culturally, and the Chinese version was established. The 161 teenagers with the first orthodontic treatment were included. This patient group was assessed for oral health-related quality of life by the Chinese version of the MIQ and Children's Perception Questionnaire (11-14 years old). The reliability and validity of the Chinese version of the MIQ were evaluated statistically by Spearman and factor analysis. Results : A total of 161 valid questionnaires were collected. The internal consistency Cronbach's α of the Chinese scale was 0.887. The correlation coefficient between items and the scale ranged from 0.000 1 to 0.824. A significant positive correlation of the scores was noted between the translated scale and the Children's Perception Questionnaire (11-14 years old), and the correlation coefficient was 0.444 (P<0.001). Conclusion The reliability and validity of the Chinese version of the MIQ are reliable and can be applied for clinical orthodontic treatment.

Objective:To explore the application of the Simodont dental trainer in preclinical manual dexterity training for dental students of different grades, and to discuss its effect by quantitatively evaluating their practice results.Methods:The evaluation was conducted among 118 students in the Department of Stomatology, Shantou University Medical College from Batch 2015 to Batch 2018. Each student had five different manual dexterity modules for training. Each module had three levels of difficulty and was required to be completed in 30 minutes. The assessment index included Target, Leeway Bottom and Sides, Container Bottom and Sides, which was provided by the Simodont dental trainer. The operating time (in seconds), the displacement of the dental hand pieces and the dental mirrors (in meters) were simultaneously recorded. SPSS 25.0 was used for statistical analysis.Results:For the index Target, Leeway Bottom and Sides, Container Bottom and Sides, the results showed that there was a statistical difference between students who passed pre-clinical training and who did not take the professional course ( P < 0.001). For the index Target, differences were showed among students from different grades in all modules ( P < 0.001). Conclusion:The circle module, channel module, hollow-circle module and cross-module in the Simodont dental trainer have sensitivity to discriminate the manual dexterity of different levels of dental students. The further assessment of the discrimination of the manual dexterity is required for assume-block module. The Simodont dental trainer can quantitatively measure the manual dexterity of dental students, which is important for the quantitative evaluation of dental preclinical education.

For displaying the three-dimensional (3D) digital model of teeth, we constructed a digital learning platform of "oral anatomy and physiology-tooth morphology" based on the WeChat small program of smart phones integrating teaching resources like texts, pictures, videos, three-dimensional animation and others. The textual content of tooth morphology was edited according to the Chinese textbook Oral Anatomy and Physiology (seventh edition) of the People's Health Publishing House and Wheeler's Dental Anatomy, Physiology and Occlusion. After photographing and cone beam CT scanning the tooth in vitro, JPEG file of tooth contour and DICOM file of tooth cross section were obtained. Continuous tomographic dynamic pictures of the tooth and 3D videos was presented by adopting software of Photoshop CS6, CS 3D imaging (affiliated simple software of cone beam CT), Snagit, Video Editor and Aijianji. Following steps of WeChat official website to register, develop, compose code, upgrade pictures and texts, submit to be verified and release, small program "Dental Anatomy Learning Platform" was completed and put into use. According to the survey, 90.3%(93) users believed the small program is helpful to learn Oral Anatomy and Physiology, especially in deepening the understanding of the tooth morphology and structure; 96.1%(99) users considered that the small program can be added to the classroom as a supplement, but it can't replace the textbook totally. The development of "Dental Anatomy Learning Platform" will provide methodological guidance for the development and integration of various dental teaching resources on the internet.