The treatment of chronic middle ear infection often includes surgery, which addresses areas of the middle ear and the mastoid cavity affected by the infection. Several factors favor the filling of the opened mastoid cavity after the so-called radical mastoidectomy. Many materials with different qualities have been used over the decades as mastoid obliteration materials, either by themselves or in a combined manner. 

In the clinical part of this study, bioactive glass (BG) S53P4 particles were used to obliterate the mastoid cavity of 26 patients. The second and third part of this study examined the solubility and strength of fibrin glue-bioactive glass– and cyanoacrylate glue-bioactive glass –composites in vitro. Finally, a keratinocyte cell model was used to determine what kind of an effect bioactive glass S53P4 particles might have on the cells of ear cholesteatoma disease, or on the cells of normal skin of the surgical area. 

Based on the results of this study, bioactive glass S53P4 as a mastoid cavity obliteration material produces a dry, safe ear, and may help to achieve a more normal appearance and function of the outer ear canal. Fibrin glue seems to be a suitable addition to BG granules, as it binds to BG granules making clinical use easier, but does not have a negative influence on the solubility process of BG. Cyanoacrylate glue, on the other hand, binds BG granules into a very solid composite structure that retains its strength in spite of a 30-day water exposure. It does not seem ideal to be used with BG granules in mastoid obliteration, but it might be a candidate for fixation of rigid BG composite implants. Based on the data of the in vitro cell model using immortalized HaCaT keratinocytes, BG S53P4 seems to inhibit the growth of keratinocyte cells and appears to trigger cell apoptosis with a direct cell-BG granule –contact. As these effects are constrained, BG S53P4 could have potential to reduce the likelihood of ear cholesteatoma recurrence, while not being unnecessarily harsh to normal skin.