SAGAING, Myanmar (Reuters) - There is an old joke in Myanmar about the man with chronic toothache who travels to neighboring Thailand to see a dentist.
Bemused, the Thai dentist asks him: "But surely you have dentists in Myanmar?"
"Of course," the man replies. "We have some of the best dentists in the world. It's just that in our country nobody can open their mouth."
With scores, possibly hundreds, of Buddhist monks and leading dissidents still behind bars six months after last year's democracy protests, the joke is truer than it has been at almost any time in 46 years of unbroken army rule in the former Burma.
But despite the threat from one of the world's most repressive regimes and its virtually all-seeing network of spies and informants, dissent and criticism -- albeit heavily couched in innuendo and allegory -- bubble away.
A case in point is the Most Venerable Ashin Nyanissara, the 71-year-old head of the International Buddhist Academy in Sagaing, a sleepy town but major centre of religious scholarship 20 km (12 miles) west of Mandalay, Myanmar's second city.
Although he took no part in September's marches, the abbot's teachings are now hot property on the underground DVD scene -- alongside, in a bizarre quirk of fate, the latest Rambo movie featuring an ageing Sylvester Stallone taking on the Burmese army.
In one disc, the respected monk expounds on the murderous excesses and subsequent conversion to Buddhism of the third century BC Indian emperor Ashoka the Great.
In another, he tells the tale of a group of ignorant monkeys who pull up a plantation of saplings to find out why some grow faster than others. Even though they are all replanted, the trees, of course, quickly wither and die.
It is not hard to divine the message given the junta's well-founded reputation for brutality. At least 31 people died in the September crackdown, according to the United Nations.
Inevitably, agents from the feared Military Intelligence (MI) came knocking and confiscated the DVDs, which were deemed of sufficient importance to warrant a screening at a junta cabinet meeting in Naypyidaw, the new capital.
Thankfully for the abbot, the generals didn't get the joke, one senior monk in Sagaing told Reuters.
"They all thought 'We're not foolish people. We are wise people, so it can't be referring to us,"' he said with a chuckle. "But the moment people heard MI had seized the recordings, they started selling like hot cakes."
It is not just monks who raise their voices against the regime and its disastrous handling of an economy that ranked as one of Asia's brightest prospects at independence from Britain in 1948.
Besides the opposition National League for Democracy (NLD), led by detained Nobel laureate Aung San Suu Kyi, all number of underground groups circulate, unified mainly by a loathing for the military and a reliance on the Internet to communicate.
"We don't need code names. We just use e-mail," one leading activist told Reuters at a meeting in a safe house in Yangon, the former capital. "They're not smart enough to be able to read it."
The most potent such group remains the "88 Generation Students," named after a brutally crushed 1988 uprising.
When the junta unveiled an election timetable last month, the group managed to come up with an official response -- a denouncement of the plan -- within 24 hours even though its leaders are all in jail, hiding or exile.
The frequent arrest and imprisonment of actors and comedians in the last 20 years is also testament to the central role they play in giving voice to the frustrations of the country's 53 million people.
Notable among the 3,000 people rounded up in the September crackdown were Zarganar, one of Yangon's hottest comedy acts and author of the dentist joke, and Par Par Lay, lead member of Mandalay's famous "Moustache Brothers" troupe.
Between them, the trio have spent more than 12 years behind bars for cracking jokes about the junta. At the moment they are being allowed to stage their nightly shows, a ribald mixture of slapstick, political satire and classical dance.
Significantly, however, the act is limited to English and the stage is the living room of the brothers' run-down home. Members of the audience are only ever tourists or spies.
"We're allowed to keep going because we're dead meat already," said Lu Maw, the only one of the brothers to have evaded jail time. "I'm just a comedian, but the only time I can open my mouth is inside my own home."
Editing by Michael Battye and Megan Goldin