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Introduction: In UK universities, caries removal teaching utilises plastic teeth. This format does not enable students to learn how to distinguish between tooth layers and caries via tactile feedback. The aim of this study was to assess the applicability of a novel, 3D‐printed carious tooth within caries removal teaching. Materials and methods: Single‐material 3D‐printed teeth containing simulated tactile caries were developed and 14 final‐year undergraduates were briefed to remove caries and minimise damage to healthy tissue within the tooth. Students completed evaluation questionnaires for their opinion of 3D‐printed teeth in comparison to plastic teeth and perceived confidence to subsequently treat patients. Cavity preparation perimeters were measured, using photographs with a standard protocol. Heat map analysis illustrated variation in location and extent of cavity preparations produced by the cohort. Results: Student feedback indicated the 3D‐printed caries exercise was positively received, 71.4% agreed 3D‐printed teeth would have better prepared students for patient treatment; 78.6% rated their preclinical stress/anxiety as 'very high' or 'high' and 57.1% agreed that if preclinical teaching incorporated 3D‐printed teeth, their stress/anxiety when treating their first caries patient would have been reduced. The average perimeter of cavity preparation indicated relative variation, with a maximum perimeter of 19.6 mm and a minimum of 10.7 mm, and a range of 8.9 mm. Discussion: Introducing 3D‐printed teeth into preclinical teaching would allow students to gain confidence in clinically relevant experience in tactile aspects of caries treatment earlier in their training than currently possible. Conclusion: This study demonstrates student acceptance of an alternative caries removal teaching method, with potential to increase aptitude in caries removal in a clinically relevant manner. [ABSTRACT FROM AUTHOR]

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The use of surface matching software with intraoral scanners is developing rapidly which increases the need for accessible, accurate and validated measurement software. This investigation compared the current gold-standard Geomagic Control software to a purpose-built software "WearCompare". Artificially created occlusal defects of a known size were created on 10 natural molar teeth scanned with a structured-light model-scanner (Rexcan DS2, Europac 3D, Crewe). The volume change, maximum profilometric loss and mean profilometric loss were obtained from both Geomagic Control (3D Systems, Darmstadt, Germany) and WearCompare (leedsdigitaldentistry.com). Duplicated datasets were randomly repositioned and re-alignment performed. The effect of the re-alignment was calculated by analysing differences between the known defect size and defect size after re-alignment using the same measurement metrics. Lastly, clinical wear measurements were compared on natural molar surfaces (n = 60) over 6 months using study models collected from a previous longitudinal trial. Data analysis was performed in SPSS v25 (paired t-tests, Pearson correlations, p < 0.05). Measurement correlation between the softwares was greater than 0.97 (p < 0.001) for all measurement metrics. The volume change error (SD) after alignment was −0.67 mm3(1.14) for Geomagic and −0.06 mm3(0.93) for WearCompare (p = 0.140 and r = 0.065, p = 0.86). Measurement errors were observed after alignment in both softwares and no statistical differences were observed between softwares. The volume change on the clinical dataset over 6 months was +0.29 mm3(3.97) in Geomagic and −0.30 mm3(1.82) for WearCompare (p = 0.19 and r = 0.61, p < 0.001). The mean profile gain was 42.86 μm(40.19) for Geomagic and 32.17 μm(23.72) for WearCompare (p = 0.048). Correlations between the softwares were greater than 0.6 for all measurement metrics except for mean profile gain. WearCompare is a comparable tool to Geomagic for quantifying erosive tooth wear. WearCompare reported statistically less profile gain indicating less error but further research is needed to reduce the human errors in both softwares. [ABSTRACT FROM AUTHOR]

Abstract Objectives Alignment procedures have yet to be standardised and may influence the measurement outcome. This investigation assessed the accuracy of commonly used alignment techniques and their impact on measurement metrics. Methods Datasets of 10 natural molar teeth were created with a structured-light model-scanner (Rexcan DS2, Europac 3D, Crewe). A 300 μm depth layer was then digitally removed from the occlusal surface creating a defect of known size. The datasets were duplicated, randomly repositioned and re-alignment attempted using a "best-fit" alignment, landmark-based alignment or reference alignment in Geomagic Control (3D Systems, Darmstadt, Germany). The re-alignment accuracy was mathematically assessed using the mean angular and translation differences between the original alignment and the re-aligned datasets. The effect of the re-alignment on conventional measurement metrics was calculated by analysing differences between the known defect size and defect size after re-alignment. Data were analysed in SPSS v24(ANOVA, post hoc Games Howell test, p < 0.05). Results The mean translation error (SD) was 139 μm (42) using landmark alignment, 130 μm (26) for best-fit and 22 μm (9) for reference alignment (p < 0.001). The mean angular error (SD) between the datasets was 2.52 (1.18) degrees for landmark alignment, 0.56 (0.38) degrees for best-fit alignment and 0.26 (0.12) degrees for reference alignment (p < 0.001). Using a reference alignment statistically reduced the mean profilometric change, volume change and percentage of surface change errors (p < 0.001). Significance Reference alignment produced significantly lower alignment errors and truer measurements. Best-fit and landmark-based alignment algorithms significantly underestimated the size of the defect. Challenges remain in identifying reference surfaces in a robust, clinically relevant method. [ABSTRACT FROM AUTHOR]