To compare the dental casts of maxillary fibrous ridges made from the Watson (1970) ‘window' technique with casts made from a new technique advocated by Lynch and Allen (2006).
Methods:
Two impressions where taken of two different patients'; one impression using the Watson technique, the other the Lynch/Allen method. For each patient a palatal locating device was used to orientate the two casts in an identical 3D position, relative to a precision diamond saw. Each cast was sectioned laterally at four identical predetermined distances. The sectioned casts were placed into a custom built photographic jig with the camera set at a predetermined distance. One to one images of the cut surfaces were produced. The images were imported into Adobe photo shop and converted into a line graphic. For each patient the images taken at corresponding points on the two different casts where assigned different colours and overlaid producing the final image.
Results:
The photographs and line diagrams show the differential movement of the fibrous ridge between the two impression techniques. In this study the incisive papillae of the casts from the Lynch technique are displaced more posteriorly.
Conclusion:
Within the confines of this study the two impression techniques produced distinctly different casts; with the maxillary fibrous ridges displaced in a consistent but different manner. Further studies with greater numbers are required to confirm the consistency of these results and to enquire into the clinical success of dentures made from the 2 impression techniques.