When a team of archaeologists recently came across some 15,000 year-old human remains, they made an interesting discovery. The teeth of those ancient humans were riddled with holes. Their cavities were caused by the same thing that still plagues us today, specific tiny microbes that live in our mouths. These microbes are with us soon after birth. We typically pick them up as babies from our mothers' mouths. And as our teeth erupt, they naturally begin to accumulate communities of bacteria. Depending on what we eat, and specifically how much sugar we consume, certain microbes can overpopulate and cause cavities. Diets high in sugary foods cause an explosion of bacteria called mutans streptococci in our mouths. Like humans, these microorganisms love sugar, using it as a molecular building block and energy source. As they consume it, the bacteria generate byproducts in the form of acids, such as lactic acid. Mutans streptococci are resistant to this acid, but unfortunately, our teeth aren't. While each human tooth is coated in a hardy, protective layer of enamel, it's no match for acid. That degrades the armor over time, leaching away its calcium minerals. Gradually, acid wears down a pathway for bacteria into the tooth's secondary layer called the dentin. Since blood vessels and nerves in our teeth are enclosed deep within, at this stage, the expanding cavity doesn't hurt. But if the damage extends beyond the dentin, the bacterial invasion progresses causing excruciating pain as the nerves become exposed. Without treatment, the whole tooth may become infected and require removal all due to those sugar-loving bacteria. The more sugar our food contains, the more our teeth are put at risk. Those cavemen would hardly have indulged in sugary treats, however, so what caused their cavities? In meat-heavy diets, there would have been a low-risk of cavities developing because lean meat contains very little sugar, but that's not all our early human ancestors ate. Cavemen would also have consumed root vegetables, nuts, and grains, all of which contain carbohydrates. When exposed to enzymes in the saliva, carbohydrates get broken down into simpler sugars, which can become the fodder for those ravenous mouth bacteria. So while ancient humans did eat less sugar compared to us, their teeth were still exposed to sugars. That doesn't mean they were unable to treat their cavities, though. Archaeological remains show that about 14,000 years ago, humans were already using sharpened flint to remove bits of rotten teeth. Ancient humans even made rudimentary drills to smooth out the rough holes left behind and beeswax to plug cavities, like modern-day fillings. Today, we have much more sophisticated techniques and tools, which is fortunate because we also need to contend with our more damaging, sugar-guzzling ways. After the Industrial Revolution, the human incidence of cavities surged because suddenly we had technological advances that made refined sugar cheaper and accessible. Today, an incredible 92% of American adults have had cavities in their teeth. Some people are more susceptible to cavities due to genes that may cause certain weaknesses, like softer enamel, but for most, high sugar consumption is to blame. However, we have developed other ways of minimizing cavities besides reducing our intake of sugar and starch. In most toothpastes and many water supplies, we use tiny amounts of fluoride. That strengthens teeth and encourages the growth of enamel crystals that build up a tooth's defenses against acid. When cavities do develop, we use tooth fillings to fill and close off the infected area, preventing them from getting worse. The best way to avoid a cavity is still cutting down on sugar intake and practicing good oral hygiene to get rid of the bacteria and their food sources. That includes regular tooth brushing, flossing, and avoiding sugary, starchy, and sticky foods that cling to your teeth between meals. Gradually, the population of sugar-loving microbes in your mouth will decline. Unlike the cavemen of yesteryear, today we have the knowledge required to avert a cavity calamity. We just need to use it.
Kada je grupa arheologa nedavno naišla na ljudske ostatke stare nekih 15 000 godina, došli su do zanimljivog otkrića - zubi ovih drevnih ljudi su bili prekriveni rupama. Njihov karijes je bio prouzrokovan onim što nas muči i danas, određenim majušnim mikrobima koji žive u našim ustima. Ovi mikrobi su sa nama ubrzo nakon rođenja. Obično ih kao bebe pokupimo iz majčinih usta. Kako nam zubi izbijaju, prirodno počinju da akumuliraju kolonije bakterija. U zavisnosti od toga šta jedemo i naročito koliko šećera unosimo, određeni mikrobi se mogu prenamnožiti i izazvati karijes. Ishrana bogata slatkom hranom izaziva eksploziju bakterija pod nazivom mutans streptokoke u našim ustima. Kao i ljudi, ovi mikroorganizmi vole šećer i koriste ga kao molekularni gradivni blok i izvor energije. Dok jedu šećer, bakterije stvaraju nusproizvode u obliku kiselina, kao što je mlečna kiselina. Mutans streptokoke su otporne na ovu kiselinu, ali, nažalost, naši zubi nisu. Iako je svaki ljudski zub obložen otpornim zaštitnim slojem gleđi, ona ne može da se nosi sa kiselinom koja vremenom slabi zaštitni sloj i rastapa minerale kalcijuma. Kiselina postepeno utire put bakterijama u drugi sloj naših zuba koji se zove dentin. Pošto su krvni sudovi i živci u našim zubima usađeni duboko, u ovom stadijumu, karijes koji se širi nas ne boli. Ipak, ako se oštećenje proširi dalje od dentina, invazija bakterija napreduje i izaziva nepodnošljiv bol dok živci postaju izloženi. Bez lečenja se ceo zub može inficirati i vađenje može biti neophodno, a sve zbog tih bakterija-šećeroljubaca. Što više šećera naša hrana sadrži, naši zubi su više izloženi riziku. Ipak, malo je verovatno da su ti pećinski ljudi uživali u slatkišima. Pa, od čega su oni dobijali karijes? U ishrani bogatoj mesom postojao je veoma mali rizik za nastajanje karijesa jer posno meso sadrži veoma malo šećera, ali to nije sve što su naši preci jeli. Pećinski ljudi su takođe konzumirali korenasto povrće, koštunice i žitarice, koje sve sadrže ugljene hidrate. U kontaktu sa enzimima iz pljuvačke ugljeni hidrati se razgrađuju na proste šećere, koji mogu postati hrana onim proždrljivim bakterijama iz usta. Iako su drevni ljudi zaista jeli manje šećera u poređenju sa nama, njihovi zubi su ipak bili izloženi šećeru. To ipak ne znači da nisu bili sposobni da leče karijes. Arheološki ostaci pokazuju da su pre 14 000 godina ljudi već koristili naoštren kremen za uklanjanje delova trulih zuba. Drevni ljudi su čak pravili rudimentarne bušilice da bi poravnali hrapave rupe koje bi nastajale i pčelinji vosak za punjenje rupa koji je bio nalik modernim plombama. Danas imamo prefinjenije metode i alate, što je dobro jer moramo da se borimo i protiv naših štetnih prehrambenih navika i opsesije šećerom. Nakon Industrijske revolucije pojava karijesa kod ljudi se jako povećala jer smo odjednom imali tehnološka otkrića koja su omogućavala da prerađeni šećer bude jeftiniji i dostupan. Danas neverovatan procenat od 92 posto odraslih Amerikanaca ima karijes. Neki ljudi su podložniji karijesu zbog gena koji mogu da prouzrokuju izvesne slabosti kao što je mekša gleđ, ali, u večini slučajeva, unošenje velikih količina šećera je krivac. Ipak, razvili smo druge načine smanjenja nastajanja karijesa osim smanjenja unošenja šećera i skroba. U većini pasta za zube i mnogim vodovodima koristimo male količine fluorida. To ojačava zube i podstiče razvoj kristala gleđi koji grade odbrambeni sistem zuba protiv kiseline. Kada se karijes pojavi koristimo plombe da popunimo i zatvorimo inficirano područje, čime sprečavamo pogoršanje. Najbolji način da se izbegne karijes je, i dalje, smanjivanje unosa šećera i dobra higijena zuba da bismo se rešili bakterija i njihovih izvora hrane. To uključuje redovno pranje zuba, upotrebu konca za zube i izbegavanje šećera, skroba i lepljive hrane koja se zadržava na zubima između obroka. Kolonije mikroba-šećeroljubaca u vašim ustima će se postepeno smanjiti. Za razliku od pećinskih ljudi iz prošlosti danas posedujemo znanje potrebno da se izbegne katastrofa vezana za karijes.