Organotypic cultures of gingival cells: an epithelial model to assess putative local effects of orthodontic plate and occlusal splint materials under more tissue-like conditions.
This article explores whether organotypic cultures of immortalized gingival keratinocytes constitute a suitable model for assessing the epithelial cell compatibility of two groups of dental resins, each of them representing one group used in orthodontics and temporo-mandibular disorders (TMD) therapy under conditions more closely resembling the actual tissue situation. The resins were tested with the agar diffusion assay (ADA) in conventional monolayer and organotypic cultures. Compared to the control exhibiting a neutral red destaining index of 3, the index of 4 obtained after exposure of monolayers to one soft permanent resin (Durabase) indicated the presence of a non-lytic but physiologically active substance. In contrast, the adaptation of the ADA to organotypic cultures revealed no apparent lesions at the epithelial surface by performing scanning electron microscopy, while histoarchitecture indicated the development of stratified surface epithelia. This was substantiated by undamaged cells in the uppermost cell layers and by the preservation of cell-to-cell contacts. Furthermore, indirect immunofluorescence for Ki-67 and the cytokeratins ck 14 and ck4 revealed that cell proliferation and epithelial structure were maintained, while differentiation was enhanced, possibly increasing epithelial resistance. The results obtained from the organotypic cultures suggest that (i) cell-affecting effects of materials visible in monolayer cultures may not be seen in epithelia resembling that in vivo and that (ii) enhanced differentiation may be associated with increased stability of the epithelial cells. Thus, organotypic cultures of gingival cells constitute a tissue model allowing short-term tissue compatibility studies of dental materials and rendering a potential candidate also for long-term studies.
Tomakidi
P
P
Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Germany. pascal_tomakidi@med.uni-heidelberg.de
Schuster
G
G
Breitkreutz
D
D
Kohl
A
A
Ottl
P
P
Komposch
G
G
D000180:Acrylic Resins; D000818:Animals; D001672:Biocompatible Materials; D002472:Cell Transformation, Viral; D005881:Gingiva / Q000166:cytology*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology*; D007739:L Cells; D051379:Mice; D017090:Occlusal Splints; D009856:Oncogene Proteins, Viral / Q000235:genetics; D009924:Organ Culture Techniques / Q000379:methods; D009967:Orthodontic Appliances; D027383:Papillomaviridae / Q000235:genetics; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins
D000180:Acrylic Resins; D001672:Biocompatible Materials; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; C059731:oncogene protein E7, Human papillomavirus type 16