The creative use of masks in theatre ranges from the abstract style of Japanese noh theatre to the introverted, tortured genius of Frank Sidebottom. Building on this versatility, this year's Fringe features two English theatre companies attempting to explore the tricky subjects of dementia and homelessness through the original use of masks.

Hailing from Worcestershire, Vamos Theatre are bringing their production Finding Joy to Edinburgh, charting the relationship between Joy, a woman in her 80's, and Danny, her grandson. When Joy finds herself struggling with the impact of increasing dementia, Danny steps up to the challenge of being Joy's domestic carer, creating a transformative experience for both of them.

Anyone who has experienced caring for a loved one knows the effects of dementia are no laughing matter, but Vamos Theatre founder Rachael Savage saw an opportunity to use light and shade to create a fuller, deeper picture of how a caring relationship can develop.

'Five years ago, the Hereford Courtyard approached Vamos Theatre to collaborate on a production about dementia. After months and months of research, I wondered if I'd made a huge mistake. All the stories, novels, films, news articles, documentaries were negative, depressing and all ended in death,' says Savage. 'With my piece of theatre I wanted to celebrate a life, not dwelling on the losing of a person, but the journey to keep trying to find the person, and find joy and happiness with that person.'

After months of research, Finding Joy was created as a wordless piece using full masks and music to depict Joy and Danny's interactions, aiming to capture ordinary, everyday interactions and making them into something extraordinary.

'Full mask is a powerful and emotive theatre genre,' says Savage.' Because there are no spoken words, we find that the audience engages more fully with the action and thus often forms a stronger, deeper, emotional attachment to what is happening on the stage. It's a perfect form in which to explore the social history that inspires Vamos' work.'

The Marked / credit: Idil Sukan
The subject of homelessness might seem just as daunting as dementia; Theatre Témoin are returning to the Fringe after 2013's hit The Fantasist, with a new production blending masks, puppets and physical theatre. After careful research of urban myths in environments as diverse as Rwanda and Miami, followed by a rigorous work-shopping process, the company have created a stark, modern drama set among homeless young people on the streets of London, but one with a streak of wonder running through it.

'There's an epidemic in this country at the moment of more and more people finding themselves in situations where sleeping rough seems to be the only option,' says Theatre Témoin producer Patrick Collier. 'What I wanted to explore was the individual stories of people who happened to be, among many other things, homeless, and crucially what was happening inside the heads of these individual people, people who had gone through traumatic experiences.'

The production, created with the help of the Everyman Theatre in Cheltenham, depicts the story of Jack, a homeless person who lives both in the tough reality of homelessness but also in a parallel world that exists inside his head. Jack has to navigate obstacles like the effects of his mother's alcoholism, but also the demons that his childhood traumas have freed to roam through his psyche, from evil witches to giant birds.

'We like to create playful worlds onstage, and with The Marked we set out to create a wonderland. Jack's life on the streets is mirrored in the fantastical world of his childhood imagination,' says Collier. 'There's plenty in the story of a boy who's homeless that is dark and brutal and honest, but we try to tell the story with a magic flare, and make it visually and emotionally enticing.'

Both productions seek to find a common ground with Edinburgh audiences, who recognise the artifice of the mask itself, but are prepared to look beyond and see how the performer's disguises might expose how individuals see themselves and the world outside. Collier's description of the reasons that Theatre Témoin chose to use masks mirrors the approach of Vamos Theatre too.

'Mask and puppetry can have a tendency to suck the audience in,' says Collier. 'It's a space where your imagination can run wild, and we want our audience to come in with a dreaming mind … Mask also has a way of turning the invisible into visible and turning the banal into epic, so mask became the obvious material language of the piece.'

Finding Joy, Assembly Hall, 6–14 Aug, 4.30pm, £13–£14 (£12–£13). Previews 4 7 5 Aug, £8.
The Marked, Pleasance Dome, 6–29 Aug (not 17), 1.30pm, £9–£12 (£8–£11). Previews 3–5 Aug, £7.