The allogeneic shell technique for alveolar ridge augmentation: a multicenter case series and experiences of more than 300 cases
Kämmerer PW, Tunkel J, Götz W, Würdinger R, Kloss F, Pabst A. Int J Implant Dent. 2022;8(1):48.
https://pubmed.ncbi.nlm.nih.gov/36316597/

This study is the first multicenter case series about maxgraft® cortico and shows its application in different types of alveolar ridge defects in combination with different bone substitute materials.

Purpose: maxgraft® cortico might be used for alveolar ridge augmentation as an alternative to autogenous grafts and bone substitutes. We report about a multicenter case series and our experiences of more than 300 cases using maxgraft® cortico and the shell technique for reconstruction of the alveolar process to illustrate surgical key steps, variations, and complication management.

Methods: Different types of alveolar ridge defects were augmented using the shell technique via maxgraft® cortico. The space between the cortical plate and the alveolar bone was filled with either autogenous or allogeneic granules (AUG, ALG) or a mixture of both. Implants were placed after 4-6 months. Microscopic and histological assessments were performed. In addition, space filling using AUG, ALG and bovine bone substitute was discussed.

Results: Scanning electron microscopy demonstrated the compact cortical structure of maxgraft® cortico and the porous structure of allografts (maxgraft®) allowing micro-vessel ingrowth and bone remodeling. Histological assessment demonstrated sufficient bone remodeling and graft resorption after 4-6 months. In total, 372 maxgraft® cortico cases and 656 implants were included to data analysis. The mean follow-up period was about 3.5 years. Four implants failed, while all implant failures were caused by peri-implantitis. Next, 30 complications were seen, while in 26 complications implant placement was possible. maxgraft® cortico rehydration, stable positioning by adjusting screws, smoothing of sharp edges, and a tension-free wound closure were identified as relevant success factors. Space filling using allografts (maxgraft® granules) and a mixture of allogeneic granules and autologous bone resulted in sufficient bone remodeling, graft resorption and stability of the augmented bone.

Conclusions: maxgraft® cortico and the shell technique is appropriate for alveolar ridge augmentation with adequate bone remodeling and low complication rates. Allografts can prevent donor site morbidity and therefore may decrease discomfort for the patient.