# Ventral Transorbital Apicoectomy of the Maxillary Second and Third Molar Teeth in Guinea Pigs (Cavia porcellus): 26 Cases

## TL;DR

A new less invasive surgical method allows treating upper molars in guinea pigs without removing the eye, improving their welfare.

## Contribution

A novel transorbital apicoectomy technique for maxillary molars in guinea pigs that preserves the eye.

## Key findings

- The transorbital approach successfully provided access to the affected molars without eye damage in 26 cases.
- All animals recovered well post-surgery with no complications and the eye was preserved in every case.
- The method allows direct removal of diseased tooth apices while avoiding the need for eye removal.

## Abstract

Dental overgrowth and infections are common causes of feeding problems and pain in guinea pigs. When these conditions affect the last two upper teeth, which are located very close to the eye, and until now surgical treatment often required removal of the eye to gain access. The aim of this study was to describe and evaluate a new surgical approach that allows treatment of the affected tooth and the alveolus while preserving the eye. In this study, 26 procedures were performed in guinea pigs using a surgical access through the eye socket, carefully moving the eye aside without damaging it. This approach allowed direct access to the diseased tooth and its socket, which were removed using dental instruments, after which the eye and surrounding tissues were returned to their normal position. All animals recovered well without complications, and the eye was preserved in every case. This method provides a less invasive alternative to eye removal and may improve both the welfare and quality of life of guinea pigs suffering from severe dental disease.

A common cause of teeth malocclusion and feeding disorders in guinea pigs is macrodontia and odontogenic abscesses. If the maxillary second or third molar teeth are affected, surgical access to them has so far been achieved through enucleation or orbital evisceration due to their location at the base of the orbit. The study aims to demonstrate a transorbital surgical approach to the apices of the maxillary molar teeth (M2 and M3) in guinea pigs, allowing preservation of the eye. Twenty six apicoectomies of maxillary M2 and M3 were performed. The surgical approach involved a skin incision above the zygomatic arch, followed by soft tissue dissection, incision of the orbital ligament, and gentle dorsolateral displacement of the eyeball. Blunt dissection between the lacrimal and zygomatic glands provided direct access to the affected tooth apices, which were removed using a dental bur. After the procedure, the soft tissues and the eye were repositioned and the skin was sutured. All animals recovered uneventfully. The described method may be applied in cases where it is necessary to perform maxillary second and/or last molar tooth apicoectomy while avoiding damage to the eyeball. Care must be taken to protect the corneal surface of the affected eye.