PhD Scientific Days 2024

Dental Research

Developing an Animal Model to Study Palatal Tissue Degradation Using Intraoral Scanners

Text of the abstract

Introduction: Mounting evidence supports the viability of human identification through intraoral scanning (IOS) of the palate.
Aims: This research aims to delve into how tissue degradation and blood contamination impact the accuracy of IOS, specifically examining 3D surface irregularities and the recognition of palatal rugae.
Method: We procured ten fresh lamb maxillas from a local slaughterhouse, dividing them into two groups: unwashed and washed. These samples were then stored at controlled conditions of 20.5°C and 80% humidity for a duration of 20 days. Utilizing an Emerald S intraoral scanner, we conducted three scans daily of the palatal region. Subsequently, the anterior area containing rugae was digitally aligned using the iterative closest point algorithm in three distinct manners: intra-day mesh alignment to assess precision, inter-day mesh alignment from day one to subsequent days to evaluate deviation, and inter-lamb alignment on day one to gauge between-lamb differences. We quantified the mean absolute difference (MAD) between the aligned surfaces. Additionally, we measured the length and characteristics (location and value) of the largest curvatures of five rugae on each lamb. Employing a supervised machine-learning approach, we determined the specificity and sensitivity of individual ruga discrimination.
Results: The precision was significantly lower (p<0.001) in the unwashed (0.025 mm) than in the washed group (0.013 mm), but the postmortem days had no effect. In both groups, the average MAD reached the least between-lambs difference on day 5. The sensitivity of ruga recognition was 0.89 on day one and dropped to 0.69 on day 20; the specificity was between 0.59 and 0.66.
Conclusion: The study concludes that an intraoral scanner remains dependable for postmortem palate records for up to 20 days. Despite deterioration, distinguishing between identical rugae remains possible with moderate accuracy.
Fundings: The study was funded by the Hungarian Scientific Research Fund (K_22, 142142), the Hungarian Human Resources Development Operational Program (EFOP-3.6.2-16-2017-00006), and the American Society of Forensic Odontology Research Grant 2022. This study was supported by the ÚNKP-23-4-I-SE-32 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund.