Influence of material and technique of conversion on interim prosthesis fracture.

Purpose: To investigate the ability of the smart denture conversion (SDC) technique to produce a stronger interim full-arch implant restoration.

Materials and methods: Three materials (OnX Tough 3D-printed resin, milled PMMA, and injection molded PMMA) were used to fabricate 180 specimens, 60 specimens per material. Then, an equal number of specimens were assigned a conversion technique: either traditional denture conversion or smart denture conversion. The conversions were performed on a pickup jig containing two multiunit abutment replicas. Acrylic resin was used as the pickup material. After denture conversions were performed, all specimens had uniform dimensions. To evaluate mechanical strength, each specimen underwent a 3-point bend test using an Instron machine with static load testing. Data analysis employed a two-way ANOVA considering material type, method of conversion, and their interaction, with Tukey HSD post hoc tests conducted in STATA 18.0, where significance was set at p < 0.05.

Results: Results from this study are described as method of conversion, material, and the combination of method of conversion and material. The method of conversion was statistically significant for mean fracture strength, resulting in a p-value < 0.037. Choice of material showed statistically significant results for mean fracture strength, with a p-value < 0.000. The combination of method of conversion and material showed a statistically significant result for mean fracture strength with a p-value < 0.000.

Conclusion: Out of 180 specimens, the combination of OnX Tough 3D-printed specimens converted with smart denture conversion yielded the highest mean fracture strength and the highest individual fracture strength value.