Micro-CT assessment of 99 crowns showed that good pre-cementation fit did not guarantee good post-cementation fit. The Hassawat-01 prototype had favourable internal adaptation before luting but larger gap increases afterward, while VarseoSmile with RelyX Unicem performed best among evaluable combinations. This indicates an interaction between intaglio geometry and cement properties, not clinical superiority.
Key findings
- Before cementation, HS had the best internal adaptation and VS the best marginal adaptation. Gaps increased in every group after cementation; HS increased most, suggesting hydraulic resistance. VS with RelyX Unicem had the most favourable post-cementation adaptation. CE could not be reliably segmented after cementation because of radiopacity.
Why this matters globally
Printed and ceramic-reinforced polymer crowns are expanding in digital dentistry. The study warns that dry-fit assessment may overestimate final fit and that crown-cement systems should be evaluated as combinations.
Thai researcher contribution
Thammasat University, Rangsit University, Chulalongkorn University, and Srinakharinwirot University collaborated on a Thai prototype material and micro-CT assessment.
Limitations to consider
This in-vitro study lacked natural teeth, saliva, occlusal loading, ageing, and clinical outcomes. Post-cementation segmentation failed for CE, leaving incomplete comparisons, and 11 specimens per combination limit variance assessment.