Nondestructive, three-dimensional internal fit mapping of fixed prostheses.

The team used a colored impression material and a nondestructive optical setup. They first created control samples with known thicknesses using a micrometer. Light transmission was measured through these samples on a gold alloy surface. The Beer-Lambert relationship was tested across 10 to 300 microns thickness range. Next, they applied the material inside cast gold crowns seated on dies. Light transmission values were recorded at multiple points. These values were plotted against direct thickness measurements. A standard curve was developed from the control samples. Finally, they mapped 45 points inside a single crown to create a 3D representation.

Light transmission through the material followed Beer-Lambert law within the tested range. Control samples produced a valid standard curve for thickness prediction. The correlation between photometric and physical measurements was strong (r = 0.72). This correlation reached statistical significance (p < 0.001). Three-dimensional mapping of a crown’s internal space was completed in under five minutes. The method successfully predicted cement layer thickness before cementation. Forty-five measurement points provided sufficient spatial resolution. These results suggest the technique could replace destructive methods in quality control.

The study demonstrated that light transmission can predict crown fit nondestructively. The Beer-Lambert relationship proved valid for this application. The method correlates well with physical measurements of cement thickness. Three-dimensional mapping was achieved efficiently and accurately. This approach could improve dental restoration quality assurance. The technique avoids damaging the prosthesis during evaluation. It provides spatial resolution previously unattainable with nondestructive methods. These findings support further development of optical fit assessment tools.