The dentist will examine your teeth, gums, and other mouth tissues. They also might check the joints of your jaws. The dentist will use a mirror and probe (a metal pick-like instrument) to check the crown (visible part) of each tooth for plaque and evidence of looseness or decay. The dentist also will check your bite and the way your teeth fit together (called occlusion).
Oral cancer can start in any part of the mouth or throat, including the tongue. It is more likely to happen in people over age 40. A dental checkup is a good time for your dentist to look for signs of oral cancer. Pain is not usually an early symptom of the disease. Treatment works best before the disease spreads. Even if you have lost all your natural teeth, you should still see your dentist for regular oral cancer exams.
As fans of the series know, \"Alien 3\" was the third installment in what would later round out as quartet of films about Ripley (Sigourney Weaver), the only crewmember to survive the infestation of the mining vessel Nostromo in Ridley Scott's inaugural 1979 sci-fi thriller \"Alien.\" A key part of this series' fascination lies in its malleability. In contrast to other franchises such as the James Bond films and the \"Star Wars\" series, the \"Alien\" films weren't stylistically or thematically uniform. All they had in common were Ripley and the alien, or aliens, and certain images and motifs: eggs, acid, glistening teeth, scuttling tentacles and spindly legs, foggy corridors, desolate planetary landscapes, and battered commercial and military starships that had all the glamour of delivery vans or rusty refinery towers. Beyond that, each film in the series had a distinctive look and pace and rhythm. \"Alien\" was slow and moody, a true horror film in a nasty seventies vein. The second film in the series, writer-director James Cameron's \"Aliens,\" reconfigured the original's haunted-house-in-space vibe as an adventure film: part war movie, part Western, referencing everything from \"Apocalypse Now\" and \"Zulu\" to John Ford and Budd Boetticher. The fourth film, scripted by Joss Whedon and directed by Pierre Jeunet (\"Amelie\"), is a hybrid of Frankenstein story, pirate adventure and disaster picture, starring a genetically reconstituted Ripley who has alien DNA and, it seems, superpowers.
Fincher's movie was the hardest to pigeonhole, partly because it was a concoction fretted over by many cooks. As conceived by filmmaker Vincent Ward (\"The Navigator,\" \"Map of the Human Heart\"), who wrote the most buzzed-about early version of the story, it was a quasi-religious parable, set on a wooden planet populated by monks, with Ripley falling out of the sky in tandem with a stowaway xenomorph and battling it, a la Joan of Arc.
DON JOHANSON:At the time of our earliest ancestors, this place was lush andgreen. Back then, there were rivers and lakes with communities of animalsliving in and beside the water. Here were the pigs and the elephants whosefossils we found. Deep in the forest lived the apes from which we andchimpanzees are descended. The lives of today's chimpanzees hint at our closekinship with the apes. Even though they have smaller brains than we do,chimpanzees have many human characteristics. They're highly social, they have asort of language, and they use tools. In the distant past, we shared a commonancestor with these chimps, so our earliest ancestor must have been part ape,part human. For well over a century, people have been fascinated by the searchto find the missing link, a creature that would bridge the gap betweenourselves and the primitive apes. It was always thought that the key featurethat separates us from the apes is intelligence. It was logical to think,then, that the earliest ancestors would have large brains. The argument goeslike this: the chimpanzee skull holds a brain three times smaller than modernman. If increase in brain size set us on the path from ape to human, it wasthought that the missing link should have first developed a big human-likebrain. Back in the heat of Hadar, following the trail of the missing link isgrueling work. The sun pushes the temperature to over a hundred degrees. Butthere's always an air of anticipation, because you never know what might be inthe next ravine. This is a fossil-finder's dream: a perfectly complete skullpartly concealed beneath a covering a sandstone. But it's not one of ourancestors, it's a baboon, a kind of monkey. In a century of fossil hunting,skulls have always been the prize. After all, if our earliest ancestor were alarge brained ape, a skull would be the perfect proof. But the story is like adetective thriller, full of false trails, never straightforward, and it can allchange unexpectedly, because from time to time a fossil is found that is sodifferent that it entirely turns the story of our origins upside-down. Thetrail began not with the skull, but with something totally unexpected. I wassurveying late one afternoon when we were out collecting some elephant teeth,and I looked down on the ground and found in a couple of pieces this kneejoint. At first, I thought it was just from a monkey, maybe a baboon, but itwent together in a way that didn't look like any monkey. If it wasn't amonkey's knee what was it? It looked vaguely human, but how could that be? Ineeded an expert opinion. Owen Lovejoy is an anatomist, part-time forensicscientist and an expert on animal locomotion. If anyone could tell me whatsort of creature that knee belonged to, he could.
DON JOHANSON:The length of that arm bone was a real surprise, because Lucy wasonly three and a half feet tall. We urgently needed to check that all thepieces really fit together and that meant heading back to our field lab by theside of the river. So what I'm doing is just picking away, sand grain by sandgrain, the adhering stones so that we can get a close look at what the originalanatomy looked like. It's really amazing to see how much detail is actuallypreserved on these three million year old bones. Final little pieces of sandout of the marrow chamber. Brush that off. Perfect. Just perfect. The finallittle piece to the puzzle fits in right there, and fantastic. Complete ulna.Just amazing. You know, not only is it important because it's a three millionyear old ulna and so beautifully complete, but because for, of what it tells usabout Lucy. Comparing it to Lucy, for example, in terms of anatomy, these twobones, both about three million years old, are essentially identical. But it'sobvious that the new ulna is nearly twice the size of Lucy's. And suchsubstantial difference in body size really has important implications forbehavior. These fossils suggest that some of Lucy's kind were much larger thanothers, nearly twice the size. Such enormous differences are seen today inmountain gorillas, and it's clearly related to their social life. This is aharem in which a single, large male controls a group of small females. Thesilver back male is almost twice the size of the females, and this leader ofthe group, he mates with each female in turn. He can easily control all thefemales. In this lush environment, they find all the food they need withoutwandering far. And if any other male tries to invade, the silver back throwsin all his weight and attacks with his huge canine teeth. To survive ingorilla society, males have to be much larger than females, and have viciousfighting teeth. Finding an arm bone twice as large as Lucy's raised thepossibility that the new bone was from a large male, and that our ancestors fitthe gorilla pattern, that they had lived in a harem. But not all the evidencefits. The landscape Lucy lived in was very different from the lush jungle ofthe gorillas. Lucy had to range widely in her search for food, and that wouldhave made it hard for a single male to dominate a group of females. And therewere other clues that didn't match the gorilla model. Over the years, we'vefound hundreds of teeth from Lucy's kind, male and female. Surprisingly, themales have small canine teeth, just like the females. That could mean thatthere was no need for males to fight for control over females. Perhaps theyweren't living in a harem after all. Some scientists have speculated that thelack of fighting teeth in our ancestors means that males and females werepaired off in monogamous couples. For now, the evidence points both ways, butcontradictions like this keep us questioning our ideas and looking for morefossils. What we do know is that these creatures were walking like us overthree million years ago. And that was a distinct advantage. They could coverlong distances, forage for food, and carry it back, perhaps to a faithfulmating partner. We believe Lucy's species was the root of the human familytree. She is our earliest ancestor, the missing link between ape and human.And what about Lucy, herself. What did she look like? We know from the teeth,the jaw and now the skull fragments we found, that Lucy had an ape-like facewith a brain just a little larger than a chimps. She may have had dark skinand patchy hair to protect her from the sun. Walking upright freed her handsto develop a more precise grip than other apes, more like our own. And evenwith her small brain, perhaps she was beginning to have a more human likeawareness of herself and her surroundings. Lucy and her kind must have beenextraordinary creatures. We know that they persisted as a species virtuallyunchanged for over a million years. That's ten times as long as we ourselveshave been around. We know that they led relatively simple lives, because onekey feature was missing from their behavior. Yet a few hundred thousand yearsafter Lucy, some of her descendants made a major breakthrough, a breakthroughthat would have profound influence on our own evolution. They began to makethese: stone tools. Who made these tools and why? They are a clue to thenext chapter in the search for human origins.