The Treatment of sea turtle shell fractures: a novel approach using Bis-GMA-free dental composites

Aim/Introduction: This paper aims to investigate the use of Bis-GMA-free dental composite as a valid method of repairing Sea Turtle shell fractures.

Materials and methods: One shell with multiple fractures from a Caretta caretta (Linnaeus, 1758) turtle, donated by the Veterinary Department of University of Messina, was used to perform the investigation. An expert operator repaired the shell using Bis-GMA-free ENAMEL plus HRi® BIO FUNCTION composites, MICERIUM S.p.A., Avegno (GE).
The repairing protocol consisted of six stages: preparation, adhesion, composite layering, polymerization, finishing and polishing, and immersion. Microscopic and macroscopic analysis was performed after polishing (T0) and after 24h immersion in sea water (T1) using a SEM microscope and a Canon EOS 90D photographic device.

Results and Discussion: The SEM analysis shows a good interface between the composite and the shell at both T0 and T1, with no relevant differences being noted in adhesion. The macroscopy at T0 demonstrates the good memetic ability of the BIS-GMA-free composite. At T1, the repaired area looks a little bit different in colour (different value, same hue and chroma). This change is due to the rehydration process. Current guidelines for shell repair recommend resins, adhesives, synthetic materials, and biocompatible fabrics. Repair methods range from mechanical fixation to adhesive use, or a combination, depending on the damage’s severity and nature. The complete healing of the chelonian shell requires long periods of time (1-2 y.), so the role of covering materials is to protect the underlying granulation bed, ensuring a longer healing process.

Conclusions: Using Bis-GMA-free composites offers an aesthetically pleasing and safe alternative to traditional materials. The combination of the physical and optical properties of Bis-GMA-free composites allows for long-lasting and natural results, faithfully reproducing the structure and colour of the chelonian shell. These results require further and in vivo investigations to optimise shell repair and to ensure the survival of these fascinating creatures.