Evaluation of Tooth Position Change Between Preparation and Cementation appointments for Overlay Restorations

Aim: This study aimed to evaluate possible tooth displacement—of the prepared tooth or adjacent/antagonist teeth—between the two clinical appointments required for overlay restoration, with or without the use of temporary filling. Materials and Methods: After ethical approval, 42 patients requiring one or more overlay restorations on upper or lower premolars and molars were enrolled (total: 50 restorations). Restorations were divided into two groups based on the presence or absence of temporary material between visits. Intraoral scans were performed after preparation and at a second appointment (minimum 1 week later). STL files were analyzed with Geomagic Wrap® to assess positional changes of the prepared tooth, mesial/distal teeth, and antagonists. Two analyses were carried out: the first evaluated the effect of provisionalization (YES/NO) and tooth location (prepared/adjacent/antagonist), while the second assessed provisionalization (YES/NO) and tooth type on maximum displacement. Post-hoc tests were run using the Holm-Sidak method with significance set at p<0.05. All data were analyzed using SigmaPlot 14.0 (Systat Software Inc.). Results: Prepared teeth shifted significantly more than both adjacent and opposing teeth (p<0.001). Tooth type and its interaction with provisionalization had a notable effect on movement (p<0.001 and p=0.035, respectively). In particular, upper molars exhibited greater displacement when no provisional restoration was placed, compared to upper (p<0.001) and lower premolars (p=0.009). Placement of a provisional significantly reduced movement in upper molars (p=0.002). Among non-provisionalized teeth, lower molars also showed more movement than upper premolars (p=0.049). Conclusions: Depending on the type of tooth, the use of a temporary filling may help prevent undesired dental movements between appointments, improving the fit of the final restoration and reducing chairside adjustment time. Further studies with larger samples are needed to confirm these findings.