Sutural loading in bone‐ versus dental‐borne rapid palatal expansion: An ex vivo study

Objectives To measure and compare the success rate and strains generated during bone‐ (BRPE) and dental‐borne rapid palatal expansion (DRPE) at the alveolar bone, zygomaticomaxillary (ZMS) and internasal (INS) sutures. Additionally, the magnitude and the pattern of midpalatal suture (MPS) separation in the 2 groups was assessed. Setting and Sample Population The study was performed ex vivo using 28 pig heads. Materials and Methods Heads were dissected, and the MPS, ZMS, INS and the alveolar bone were exposed. A differential‐variable‐reluctance‐transducer (DVRT) was installed across the MPS, and single‐element strain gauges were installed at the remaining sites. Expanders were placed and activated at one turn per minute for 30 turns. Strains at the alveolar bone and the sutures and the separation of the MPS were measured. Results Successful expansion of the MPS was achieved in 69% of the BRPE subjects compared to 27% in the DRPE group. The average separation of the MPS was higher (230 ± 109 µm per turn vs. 79 ± 61 µm) and the MPS opening happened at an earlier stage of expansion in the BRPE. Higher strains at the ZMS were seen in the BRPE group, while higher strain at the alveolar bone was found in the DRPE group. Conclusions The BRPE group demonstrated more successful and effective expansion of the MPS. Higher strain was found at the alveolar bone in the DRPE. A tendency for higher strain at the ZMS was noticed in the BRPE.