Objectives: This study aimed to compare the haptic perception of clinicians to the cutting response of 3D‐printed typodont teeth and commercial typodont teeth and human extracted teeth.Methods: Twenty clinicians were asked to perform a Class I cavity preparation on commercial typodont teeth, 3D‐printed typodont teeth, and human extracted teeth, while the forces were recorded via a three‐axis load cell. The haptic perception of clinicians was also evaluated through a response questionnaire comparing commercial and 3D‐printed typodont teeth.Results: The study found that clinicians used similar forces (p = 0.53) to cut both the 3D‐printed typodont teeth (1.37 N) and the human extracted teeth (1.44 N), but more force was needed to cut the commercial typodont teeth (3.71 N). The response questionnaire indicated that clinicians rated the 3D‐printed typodont teeth highly compared to the commercial teeth. The 3D‐printed dentine received favorable feedback from clinicians, and the 3D‐printed enamel was rated higher compared to the commercial equivalents.Conclusions: The results of the study suggest that 3D‐printed typodont teeth offer a comparable haptic perception to human extracted teeth and can be used as an effective tool for preclinical dental learning. Moreover, the study highlights the advantages of 3D‐printed typodont teeth over commercial typodont teeth in terms of haptic perception.

Introduction: This study aimed to investigate students' perceptions of the use of 3D-printed typodonts by implementing a questionnaire and evaluating the students' comparisons between extracted, commercial and 3D-printed teeth.Methods: Ethical approval was obtained (QMER20.586/2021) and questionnaire feedback was collected anonymously using an online survey. A total of 143 fourth- and fifth-year dental students were approached to participate during pre-clinical courses focussing on root canal therapy. The tooth design was based on micro-CT data of an extracted maxillary central incisor and 3D-printed with haptically-similar materials produced in previous work. The questionnaire comprised 11 Likert-scale questions, four open-ended questions, two “yes” or “no” questions and three closed-ended questions.Results: Eighty questionnaires were returned. Overall, the feedback was favourable towards the 3D-printed typodonts compared to the commercial teeth. The biggest difference in responses was in Question 6 related to the realism of drilling the enamel when comparing 3D-printed teeth with commercial ones. Statistical analysis showed a significant difference (p < 0.05); the fourth-year's response on average, was 2.95 (±0.73) an “agree” rating, whereas the fifth-year's response was 3.98 (±0.82) with “neither agree or disagree”.Discussion: Within the limitations of this study, the 3D-printed typodonts were rated high in comparison to the commercial teeth in terms of overall operative experiences.

Introduction: Fluoride plays a major role in inhibiting enamel dissolution and promoting fluorapatite formation. Porous hydroxyapatite (HAP) discs can be used as an enamel analogue in artificial demineralisation/remineralisation studies.Method: The aim of the study was to monitor the fluoride-mineral phases formed on HAP surfaces as a function of fluoride concentration ([F⁻]) under demineralising conditions, using ¹⁹F magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy, and compare the results with a previous study using an enamel substrate. Porous HAP blocks were immersed in demineralisation solutions (0.1 M acetic acid, pH 4.0) with increasing [F⁻] (0–1450 ppm).Results: At below 50 ppm [F⁻], ¹⁹F MAS-NMR showed fluoride-substituted apatite formation; above 50 ppm [F⁻], calcium fluoride (CaF₂) was formed in increasing proportions. These results mirrored those of previous similar studies with an enamel substrate. Further increases in fluoride caused no further measurable reduction in demineralisation but increased the proportion of CaF₂ formed. The total calcium concentration [Ca] and total phosphorus [P] concentrations in the solution were measured by inductively coupled plasma atomic emission spectroscopy. At high fluoride concentrations, the solution total [P] increased, and the molar Ca:P ratios decreased to values consistent with the formation of CaF₂. However, Ca:P ratios found at low [F⁻] were higher than those in the previous enamel study and consistent with the formation of a partially fluoridated apatite.Conclusions: Under demineralising conditions, CaF₂ formed on HAP at an [F⁻] of 50 ppm and above, whereas fluoridated apatite formed at an [F⁻] below 50 ppm. The results were consistent with those obtained when an enamel substrate was used.

• please read through all the templates before choosing • pick the most relevant text template(s) from the following page and delete all others.• edit the text as necessary, ensuring that the original incorrect text is included for the record, please see the below. • please do not use any extra formatting when editing the templates, and only modify the red text unless absolutely necessary • submit to Frontiers following the instructions on this page.When the original text contained incorrect information, to preserve the scientific record, please include that text when editing the below templates. For example:There was a mistake in the Funding statement, an incorrect number was used. The correct number is "2015C03Bd051.". The publisher apologizes for this mistake.The original version of this article has been updated.In the published article, there was a mistake in the Funding statement. The funding statement for the Key Development Project of the Department of Science and Technology was displayed as "2015CBd051". The correct statement is "Key Development Project of Department of Science and Technology (2015C03Bd051).'' Template continues on the next page 