This research explores the potential exploitation of recycled PET bottles in developing dimethacrylated oligoesters to be used as alternative monomers to produce novel dimethacrylate-based dental resins. Specifically, oligoester diols derived from PET glycolysis were converted into dimethacrylated oligoesters (PET-GLY-DMs), as alternative monomers to Bisphenol-A glycidyl methacrylate (Bis-GMA). The glycolysis products were analyzed for their molecular weight using GPC and the successful conversion of hydroxyl to methacrylate groups via methacrylation was confirmed by FT-IR spectroscopy. A gradient substitute of Bis-GMA by PET-GLY-DM within Bis-GMA/TEGDMA mixtures was conducted, and the gained dimethacrylated matrices were light-cured followed by the evaluation of their physicochemical and mechanical properties. It was revealed that the newly synthesized resins exhibited lower viscosity, higher degree of conversion, and reduced mechanical properties compared to the control resins. However, the most important observation, related to environmental friendliness, was that the PET-GLY-DMs did not release Bisphenol-A, as measured by liquid chromatography. The proportions of PET-GLY-DMs, Bis-GMA, and TEGDMA in dental resin formulations were optimized to achieve similar handling properties to control resins while maintaining significant hardening and mechanical performance. This research highlights the sustainability of the chemical recycling of PET, in the synthesis of novel products with added environmental and economic benefit.