Prof. G. ChadwickAFAF AWADALLAH ALMABADI2022-05-262022-05-26https://drepo.sdl.edu.sa/handle/20.500.14154/30139ABSTRACT Background Dental restorative materials are intended to replace missing parts of the teeth or occlusal units in the oral cavity. Therefore, for them to be biocompatible with the normal tissues and cells it is a core goal of materials selection, especially when it comes to the parts that they are in direct contact with them, such as class V and subgingivally placed restorative margins. Improving biological response to such restorations could improve the gingival seal around the restorations. Two restorative materials were chosen for this work; ChemFil superior as a direct restorative material. This type of glass polyalkenoate material is recommended by the American Academy of Operative dentistry for root caries restoration. The second, material is IPS E.max Press ceramic which is used as indirect restorative material. This material is reported as a biocompatible material which makes it a potential option for use in the provision of indirect restorations with subgingival margins. There is no clarity in the literature as to which surface treatment of this material favours adhesion and proliferation of normal cells. In this work, two different biological additives were selected (collagen type I 100𝜇g/ml, fibronectin 300𝜇g/ml) both additives are normally found in the extracellular matrix and involved in fibroblast adhesion, growth and differentiation. These two additives were added to the liquid component of conventional glass polyakenoate which was then mixed with the powder part. Also, surface coating of the two restorative materials was performed as the second application method. Viability of normal oral mucosal fibroblast cells were tested using MTT assay and observation of them utilising Scanning Electron Microscopy (SEM) and light microscopy. This study illustrated that time has no effect on the viability of fibroblasts in direct contact with glass polyakenoate (ChemFil Superior) in modified and unmodified forms, but this was a different scenario to the ceramic material. Results Compared with the optical density of the control (normal fibroblasts only), ChemFil Superior can be considered cytotoxic to fibroblasts in both modified and unmodified forms at all time points of the MTT cell viability assay. This was supported by the findings of the light microscopy observations which showed a cytotoxic effect on the cells compared to the control. However, regarding material properties, there was a significant improvement in mean compressive strength of collagen modified ChemFil Superior (P<0.05) and Shore hardness when fibronectin was mixed with the material (P<0.001). In contrast, the ceramic material showed good cellular biocompatibility, in general, which improved with time. On day 1, only polished ceramic samples and fibronectin modified polished ceramic showed the best cell viability values. On day 7, all the test conditions of the ceramic samples values showed no statistical significant difference from the control, which means improved biocompatibility. The mean percentage of viable cells when cultured with unpolished ceramic samples jumped above the 100%. However, when observed under the light microscope (LM), all ceramic material scores were found to be higher than the control scores. The MTT result is supported by the findings of the SEM where cells were found well-attached to the ceramic on Day 7 confirming the good cellular biocompatibility of this restorative material. In conclusion, ChemFil Superior is cytotoxic to fibroblast cells regardless of the biomodification of this material. In contrast, IPS e.max Press ceramic exhibited good biocompatibility with fibroblast cells which was improved by the addition of fibronectin to polished surfaces. This biocompatibility is time dependant, that is improving with time. Also, under SEM, fibroblasts were found viable and attached to ceramic surfaces in the unmodien