184 Fun Facts About Dental & Dentist

How many permanent (adult) teeth does a person usually have?

They split evenly, 16 in the upper jaw and 16 in the lower, and the count includes four wisdom teeth that many people never fully grow.

How many baby (primary) teeth does a child normally grow?

Ten sit in the upper jaw and ten in the lower, and there are no premolars in the set at all - the baby molars are later replaced by premolars.

Which is the hardest substance in the human body?

Tooth enamel rates around 5 on the Mohs scale, harder than bone and about as hard as steel, yet it is brittle and cannot repair itself once chipped or decayed.

What is the soft tissue in the center of a tooth, full of blood vessels and nerves, called?

Pulp is what patients usually just call 'the nerve', and it is what a root canal removes.

Which of the four tissues of a tooth sits between the outer enamel and the inner nerve chamber?

Dentin lies between the enamel and the pulp chamber; it is yellowish, porous, softer than enamel, and keeps forming slowly throughout life.

Which type of tooth is designed mainly for tearing food?

Canines, the pointed teeth beside the incisors, tear food; incisors cut, molars grind, and premolars do a little of both.

Premolars are also known by what other name?

Bicuspids is the other name for premolars, from their two cusps or points; molars carry four or five cusps.

Wisdom teeth are formally known as which teeth?

Third molars got their nickname because they arrive so late, probably as a translation of the Latin dens sapientiae.

Which bacterium is most closely associated with tooth decay?

It feeds on sugars and excretes lactic acid, which is what actually dissolves the enamel; the bacteria live in the biofilm we call plaque.

The word 'caries', the medical name for tooth decay, comes from a Latin word meaning what?

As of 2016 roughly 3.6 billion people, nearly half the planet, had it in their permanent teeth.

An ancient Sumerian text blamed cavities on what?

The same idea shows up in ancient India, Egypt, Japan and China, and the surgeon Guy de Chauliac was still promoting it in the 14th century.

Which ancient Mesopotamian law code prescribes knocking out teeth as a punishment?

The Code of Hammurabi, around 1750 BC, orders a man's teeth knocked out for knocking out another's; Egypt's Edwin Smith Papyrus was meanwhile describing treatment of broken jaws.

Hesy-Ra, an official under the pharaoh Djoser, holds what distinction in dental history?

Hesy-Ra, around 2600 BC, is the earliest named dentist; his title Wer-ibehsenjw translates as 'Great one of the ivory cutters' or 'Great one of the dentists'.

Which Frenchman is credited as the 'father of modern dentistry' for his 1728 book The Surgeon Dentist?

Pierre Fauchard adapted tools from watchmakers, jewellers and barbers, and blamed sugar acids for decay a century and a half before germ theory.

Before dentistry was a profession, tooth-pullers used an imprecise tool named after which bird?

The dental pelican, named for its beak-like claw, levered teeth out sideways and often took healthy teeth, and sometimes part of the jaw, along with the bad one.

The world's first dental college opened in 1840 in which US city?

The Baltimore College of Dental Surgery opened in 1840; Cincinnati's Ohio College of Dental Surgery followed in 1845 and later graduated the first woman dentist.

Who was the first woman in the world to graduate from a dental college, in 1866?

Lucy Hobbs Taylor graduated from the Ohio College of Dental Surgery in 1866 after being refused for her sex; she had simply opened her own practice in 1861 instead.

Hartford dentist Horace Wells pioneered surgical anesthesia in 1844 using which gas?

He never patented it, believing freedom from pain should be 'as free as the air we breathe', and his own student William Morton later took the credit with ether.

How did Horace Wells first test his anesthetic gas on 11 December 1844?

Wells had colleague John Riggs pull his own wisdom tooth while he breathed nitrous oxide, and declared afterward he had not felt it 'so much as the prick of a pin'.

Which material was actually in George Washington's dentures, which were never made of wood?

Hippopotamus ivory, along with human and cow teeth and lead, made up his dentures; ivory stains quickly, which may be how the wooden-teeth myth started.

How many natural teeth did George Washington have left on the day of his first inauguration in 1789?

The survivor was a premolar, and he later gave it to his dentist John Greenwood as a keepsake.

Which Revolutionary hero and part-time dentist identified a friend's body by a false tooth he had wired in?

The body was Joseph Warren's, dug up nine months after Bunker Hill; it is often cited as the first forensic dental identification in America.

Which ancient people made partial dentures held with gold bands as early as the 7th century BC?

The Etruscans bound replacement teeth with gold bands from the 7th century BC; Romans likely borrowed the technique, and porcelain dentures did not arrive until around 1770.

In which US city was water fluoridation first tested, starting on 25 January 1945?

Results published in 1950 showed a big drop in cavities; the whole idea grew out of a 30-year hunt for the cause of the 'Colorado brown stain'.

Dentist Frederick McKay spent 30 years investigating a mottled-tooth condition known by what name?

Frederick McKay's 'Colorado brown stain' teeth were oddly cavity-free; in 1931 Alcoa chemist H. V. Churchill found fluoride in the local water was the common factor.

In 2015, what fluoride level did the US recommend for community drinking water?

Older guidance from 1962 allowed up to 1.2 mg/L in cooler climates, on the theory that people in hot places drink more water; the 2015 figure was 0.7 mg/L.

The first nylon-bristle toothbrush went on sale in 1938 thanks to which company's new fiber?

DuPont's new nylon went into Dr. West's Miracle-Tuft toothbrush in 1938; earlier bristles were usually Siberian boar hair, which held bacteria, dried badly and fell out.

The first electric toothbrush, the Broxodent, was invented in 1954 in which country?

The Broxodent was developed in Switzerland in 1954 by Dr Philippe-Guy Woog; studies since find powered brushes about equal to good manual brushing, with slightly less plaque.

What was the toothbrush's ancestor, a frayed twig found in Sumerian sites from 3500 BC?

The chew stick had one frayed end for brushing and a pointed end as a toothpick; its descendant, the miswak, is recommended in Islamic tradition for cleaning teeth before prayer.

In the US, daily tooth brushing did not become routine until after which event?

World War II soldiers were required to clean their teeth every day and brought the habit home; the first US toothbrush patent had been granted back in 1857.

Dr. Washington Sheffield put toothpaste in a collapsible tube after his son saw what in Paris?

His son Lucius had watched Parisian painters squeezing paint from collapsible metal tubes; the original toothpaste tubes were made of lead, and the idea spread across the industry within a decade.

Ancient Egyptian tooth powder from around 5000 BC included powdered ashes of what?

Powdered ashes of ox hooves went in with pumice, burnt eggshells and myrrh; the Greeks and Romans later added crushed bones and oyster shells for grit.

Which US brand name did Unilever give Leonard Marraffino's two-colour toothpaste invention?

Stripe grabbed 8% of the US market in its second year and never reached that share again; Unilever's Signal brand carried the same idea to Europe in 1965.

Nylon dental floss was developed during World War II by which physician?

Charles C. Bass, a New Orleans physician, developed nylon floss during World War II; nylon resisted abrasion and came in long lengths, and the Bass brushing technique also bears his name.

Dentist Alfred Fones trained his cousin Irene Newman in 1906 to be the world's first what?

Irene Newman became the first dental hygienist; Fones opened the first school for the profession in 1913, and Newman received the first hygienist license in 1917.

Which dental specialty deals with root canals and diseases of the tooth's inner tissue?

Endodontics covers the pulp and root canals; periodontics is gums and implants, and prosthodontics is dentures and bridges.

Edward Angle, creator of the edgewise appliance, is the father of modern what?

Before Angle nobody had thought of attaching an appliance to each individual tooth; orthodontics went on to become the first recognized dental specialty.

Which tooth-numbering system labels permanent teeth 1 to 32, starting at the upper right third molar?

The Universal Numbering System, used by the American Dental Association, counts permanent teeth 1 to 32 clockwise from the upper right third molar; FDI notation uses two-digit quadrant codes instead.

The earliest known written record of the tooth fairy is a 1908 'Household Hints' item in which newspaper?

The Chicago Daily Tribune ran Lillian Brown's 1908 hint advising mothers to stock up at the 5-cent counter; Delta Dental's 2023 poll put the average US payout at $6.23 a tooth.

In Spain and much of Latin America, which animal takes the tooth fairy's place, collecting children's lost teeth?

A mouse, Ratoncito Pérez, was written up in 1894 for the eight-year-old King Alfonso XIII, who had just lost a tooth; Madrid gave him a commemorative plaque in 2003.

Which early Christian martyr, her teeth broken before she was burned, is invoked against toothache?

Saint Apollonia, martyred in Alexandria in 249 AD, is the patron saint of dentists; her feast is 9 February, and in parts of Italy she even fills the tooth-fairy role.

Roughly how many teeth can some shark species shed and regrow in a lifetime?

Some sharks go through about 35,000 teeth, replacing whole rows continually; Pliny the Elder thought fossil shark teeth fell from the sky in eclipses until Nicolaus Steno set the record straight in 1667.

The narwhal's spiral tusk is actually what?

The tusk is an elongated upper-left canine tooth that can reach 3 metres; the species name Monodon monoceros means 'single-tooth single-horn'.

Which order of mammals has a single pair of continuously growing incisors in each jaw, forcing them to gnaw constantly?

Rodents take their name from the Latin rodens, 'gnawing'; elephants, kangaroos and manatees are odd in another way, replacing teeth repeatedly rather than just once.

Which human teeth typically have three roots each?

Upper molars typically have three roots, two on the cheek side and one toward the palate; lower molars and most upper first premolars have two, and front teeth have one.

What material is used for tooth-coloured fillings that bond to the tooth?

Composite resin, a plastic filled with glass particles, is shaded to match the tooth and hardened with a blue light; it bonds to enamel rather than relying on mechanical lock like amalgam.

Why can the damaged outer layer of a tooth never grow back?

Enamel contains no living cells: the ameloblasts that build it are lost once the tooth erupts, so a cavity is permanent until a dentist fills it.

How many molars, including wisdom teeth, does a full adult mouth contain?

Twelve molars, three per quadrant including the wisdom tooth, complete the set of 32 alongside eight incisors, four canines and eight premolars.

Which human teeth have the longest roots?

The upper canines have the longest roots of any tooth, around 17 mm; canines are also the only single-cusp teeth and are nicknamed eye teeth for sitting beneath the eyes.

What is the part of a tooth visible above the gum line called?

The crown is the enamel-covered part above the gum; the root sits in the jawbone, the neck is the junction between them, and the apex is the root's tip.

What is the technical name for a gap between two teeth, like the one Madonna has?

A diastema is a gap between two teeth; the French call them dents du bonheur, lucky teeth, and in Nigeria and Ghana the gap is considered attractive.

Below what pH does mouth acid begin dissolving a tooth's outer mineral layer?

Enamel starts to demineralise below about pH 5.5, the so-called critical pH; plaque bacteria turn sugar into lactic acid, which is why sweets and decay go together.

What is the anatomical name of the upper jaw bone that holds the upper teeth?

The maxilla is the upper jaw, fused to the skull and holding the upper teeth; the mandible, the lower jaw, is the skull's only large movable bone.

In medieval Europe, narwhal tusks were sold as what?

Narwhal tusks passed as unicorn horns and sold for many times their weight in gold; the Danish coronation chair at Rosenborg Castle was built from them.

About how many teeth does a great white shark have at any one time?

A great white carries around 300 teeth in several rows that move forward like a conveyor belt, replacing any that break or wear.

The largest known shark teeth, more than seven inches tall, belonged to which extinct species?

Megalodon teeth exceed seven inches and fetch steep prices from fossil collectors; Dunkleosteus, by contrast, was an armoured fish with bony blades rather than teeth.

A snail carries thousands of microscopic teeth on a ribbon-like organ called what?

The radula is a chitinous ribbon that works like a rasp; limpet radula teeth contain iron-rich goethite and rank among the strongest biological materials known.

Which group of molluscs has no rasping tongue-ribbon at all?

Clams and oysters filter-feed with cilia instead of scraping.

An elephant's tusks are enormously overgrown versions of which kind of tooth?

They are the second upper incisors; about a third of each tusk is hidden in the skull, and they keep growing around 17 cm a year for life.

How many sets of molars does an elephant go through in its lifetime?

Elephants go through six sets of molars; new ones move in from the back, and once the sixth set wears down, typically past 60, the animal can starve.

How many teeth does an adult dog have?

An adult dog has 42 teeth, 20 upper and 22 lower, compared with 28 puppy teeth and 32 in an adult human.

A rodent's gnawing teeth stay razor sharp because the hard coating covers only which side of them?

Enamel coats only the front face of a rodent's incisors; the softer dentine behind wears away faster, leaving a chisel edge without any effort.

Which animal's teeth, made of thin hexagonal tubes, give its order the name Tubulidentata?

The aardvark is the sole living member of Tubulidentata; it is born with incisors and canines that fall out unreplaced, leaving only rootless cheek teeth that grow continuously.

How often can a crocodile replace each of its roughly 80 teeth over its lifetime?

Each of a crocodile's roughly 80 teeth can be replaced up to 50 times, with a small replacement waiting beside every full-grown one; unlike an alligator's, its lower teeth show when the mouth is shut.

How long can a hippopotamus's lower canine teeth grow?

A hippo's lower canines grow continuously and can reach up to 50 cm; they stay sharp by grinding against the upper canines, and are the animal's main weapon.

What do giraffes, like cattle, have in place of upper front teeth?

Like other ruminants, giraffes have a dental pad, a tough cushion on the upper gum; they press their lower incisors against it to strip leaves, helped by a 45 cm tongue.

Nineteenth-century dentures made from dead soldiers' teeth were nicknamed after which battle?

'Waterloo teeth' were pulled from the thousands of young soldiers killed in 1815 and set into dentures; the name stayed a selling term for decades, even for teeth from later wars.

In which country was the oldest known dental work, a 14,000-year-old cleaned tooth, found?

The tooth, from Riparo Villabruna in northern Italy, had its cavity scraped with a flint point; at about 14,000 years old it is the oldest known dental intervention.

Who introduced the foot-treadle dental drill in 1871?

James Beall Morrison's 1871 foot-treadle drill reached around 2,000 rpm, fast enough to make fillings routine, and left both of the dentist's hands free.

What does the dental degree abbreviation DDS stand for?

DDS means Doctor of Dental Surgery; the DMD, Doctor of Dental Medicine, is an equivalent degree first awarded by Harvard in 1867, and US schools grant either.

In the 1964 TV special Rudolph the Red-Nosed Reindeer, which elf wants to be a dentist?

Hermey the elf abandons toy-making to become a dentist and ends up pulling the Abominable Snow Monster's teeth; the Rankin/Bass special has been broadcast every year since 1964.

Which American dentist, called the father of operative dentistry, devised the standard classification of cavities?

G. V. Black published his cavity classification in 1908 along with the principle of 'extension for prevention', and standardised amalgam formulas, earning the title father of operative dentistry.

The first bristle brushes for teeth, hog bristles on bamboo or bone handles, came from which country?

China's Tang dynasty produced the first bristle brushes, hog bristles set in bamboo or bone; before that, Sumerians used frayed twigs called chew sticks as far back as 3500 BC.

In a 2003 MIT survey, which everyday invention did Americans say they could least live without?

The toothbrush topped the 2003 Lemelson-MIT Invention Index, beating the car, the personal computer, the mobile phone and the microwave.

Which company first sold toothpaste in jars in 1873, and later adopted the collapsible tube?

Colgate sold aromatic toothpaste in jars from 1873 and moved to collapsible tubes in 1896; the tube idea came from dentist Washington Sheffield, inspired by paint tubes.

Which brand, developed by Procter & Gamble in the 1950s, was the first fluoride toothpaste to win American Dental Association approval?

Crest was developed in the 1950s by Procter & Gamble with researcher Joseph Muhler at Indiana University, and became the first ADA-approved fluoride toothpaste.

In 1819 dentist Levi Spear Parmly recommended flossing with waxed thread made of what?

Parmly's waxed silk thread is the first recorded floss; Johnson & Johnson patented floss in 1898 using suture silk, and nylon took over during World War II.

In Finding Nemo, the dentist who scoops up Nemo keeps his office in which city?

Dr Philip Sherman's dental office overlooks Sydney Harbour, at '42 Wallaby Way, Sydney'; the fish in his waiting-room tank plot Nemo's escape in the 2003 Pixar film.

What is the dental specialty devoted to treating children called?

Pedodontics, now usually called pediatric dentistry, covers patients from infancy through adolescence; periodontics treats the gums and gerodontics the elderly.

Which US state passed the first law regulating the practice of dentistry, in 1841?

Alabama passed the first dental practice act in 1841, though it was barely enforced; Maryland's Baltimore dental college had opened only the year before.

According to Delta Dental's survey, what did the tooth fairy pay per tooth in the US in 1998?

Delta Dental's first Original Tooth Fairy Poll, in 1998, found an average of $1.30 a tooth; the rate peaked at $6.23 in 2023 and fell to $5.84 in 2024.

Which teeth usually erupt first in a baby?

The lower central incisors usually come through first; the upper central incisors follow a month or two later, and the first molars arrive after the first birthday.

Which serial killer's conviction relied partly on now-discredited bite-mark evidence?

Ted Bundy's 1979 Chi Omega conviction used a bite mark on victim Lisa Levy matched to his crooked teeth; the National Academy of Sciences has since found bite marks cannot reliably identify a person.

The Nitinol wire used in modern braces was created in 1959 by which organisation?

William Buehler at the Naval Ordnance Laboratory developed the nickel-titanium alloy, named NiTiNOL after the lab; orthodontist George Andreasen introduced its shape-memory wires to braces in 1971.

Orthodontics is the dental specialty that deals with what?

Orthodontics corrects misaligned teeth and jaws; its sister field, dentofacial orthopedics, guides facial growth, and a 2020 review put worldwide malocclusion prevalence at 56%.

Which Nazi leader's 1945 remains did Soviet investigators identify through his dental bridgework?

Adolf Hitler's charred remains were matched by Soviet investigators to his dental records and bridgework, confirmed by his dentist's assistant Käthe Heusermann in May 1945.

In Angle's system, which class describes an underbite?

Class III, with the lower molars ahead of the upper, is the underbite; Class II is the overjet family, and Class I means the molars meet normally with crowding or spacing elsewhere.

Braces invented by Craven Kurz in 1976 are fixed to which surface of the teeth?

Kurz's lingual braces sit on the inner, tongue side of the teeth, which makes them nearly invisible; the trade-off is a tongue that takes a while to adjust to them.

Dental sealants are painted onto which part of the teeth to block decay?

Sealants are thin resin coatings painted into the pits and fissures of molar chewing surfaces, usually in childhood, blocking the grooves where food and bacteria lodge.

Where did Zia Chishti get the idea for Invisalign?

Chishti, wearing a retainer as an adult patient after his own teeth relapsed, reasoned that a series of small retainer-like devices could add up to one large movement.

The best-known removable retainer, with a metal wire around the six front teeth, is named after whom?

The Hawley retainer, designed by Charles Hawley in 1919, runs a labial wire across the six front teeth to stop them drifting; vacuum-formed clear retainers are the modern alternative.

Orthodontic headgear differs from braces in what obvious way?

Headgear is worn partly outside the mouth, with straps around the head or neck anchoring a facebow hooked into molar bands; it is reserved for severely misaligned bites.

Who published the first paper on palatal expansion, in the journal Dental Cosmos in 1860?

Emerson Angell described splitting the palate with a jackscrew in Dental Cosmos in 1860; the idea was ridiculed, and the American Dental Association's president opposed widening the arch.

What is the term for an extra tooth beyond the normal count?

A supernumerary tooth is any extra beyond the normal 20 or 32; the commonest is a mesiodens between the upper central incisors, while hypodontia means teeth are missing.

Bleeding, spongy gums in scurvy come from a lack of which vitamin?

Vitamin C is needed to make collagen, so without it gums swell and bleed and teeth loosen; James Lind's 1747 citrus trial pointed the way to a cure.

What is the process, in which titanium bonds to bone, that underpins modern dental implants?

Osseointegration, Per-Ingvar Brånemark's term for living bone bonding directly to titanium, was found by accident when a titanium chamber set in a rabbit's leg bone could not be removed.

In what year did Brånemark place his first titanium dental implant in a human?

Brånemark fitted Gösta Larsson with titanium implants in 1965; Larsson kept them for over 40 years, until his death, as the first modern dental implant patient.

Which chemist created procaine in 1905 and gave it the trade name Novocain?

Alfred Einhorn, a Munich chemist, synthesised procaine in 1905 and named it Novocain, from Latin nov- ('new') and the -caine ending used for anesthetic alkaloids.

Lidocaine, the dentist's staple anesthetic, was first synthesized in 1943 under what name?

Nils Löfgren's team synthesised it as xylocaine, after the xylidine it is made from; it was the first amino amide-type local anesthetic and reached the market in 1948.

Which pioneer of antiseptic surgery gave his name to a mouthwash launched in 1879?

Joseph Lister pioneered antiseptic surgery at the Glasgow Royal Infirmary in the 1860s; Joseph Lawrence's 1879 antiseptic was named Listerine in his honour.

Listerine's sales took off in the 1920s when it was marketed as a cure for what?

Halitosis was then an obscure medical term for bad breath.

Which German dentist made one of the first intra-oral dental X-rays in January 1896?

Otto Walkhoff improvised the setup in Braunschweig in January 1896, weeks after Röntgen's discovery, holding a glass plate in his own mouth for a 25-minute exposure.

Gunfighter Doc Holliday earned his dental degree at age 20 from a college in which city?

Holliday graduated from the Pennsylvania College of Dental Surgery in Philadelphia in 1872; he practised briefly in Georgia before tuberculosis and the frontier intervened.

Western novelist Zane Grey opened a practice in which profession in New York City in 1896?

Grey took a dentistry degree at the University of Pennsylvania and practised in New York as Dr. Zane Grey until his novels began to sell.

Dental amalgam fillings are an alloy of which liquid metal?

Mercury, liquid at room temperature, is mixed with particles of silver, copper or tin to make amalgam; a Ming dynasty text of 1505 gave an early recipe.

What inert material is typically used to fill cleaned canals at the end of a root canal treatment?

Gutta-percha, a latex from Malaysian trees, is warmed and packed into the cleaned canals together with a zinc oxide eugenol or resin sealer.

What percentage of tooth enamel is mineral, the highest of any body tissue?

Enamel is about 96% mineral by weight, the rest water and organic matter, which is why it is the body's hardest tissue yet brittle.

What is the primary mineral in tooth enamel?

Hydroxyapatite, a crystalline calcium phosphate, makes up nearly all of enamel's mineral; fluoride converts its surface to more acid-resistant fluorapatite.

What is the medical term for excessive teeth grinding or jaw clenching?

Its global prevalence, awake and asleep, is roughly 22%.

Xerostomia is the medical term for which condition?

Xerostomia is dry mouth from too little saliva, a common side effect of many medicines; without saliva to buffer acid and wash away food, decay accelerates.

Tartar, which only a professional cleaning can remove, is a hardened form of what?

Tartar, or calculus, is plaque that has mineralised with calcium from saliva; once hardened it cannot be brushed away and must be scaled off.

What gives a beaver's incisors their orange colour?

The thick, iron-hardened enamel keeps their ever-growing teeth strong.

Baleen plates, which filter-feeding whales have instead of teeth, are made of what?

Baleen is keratin, the same protein as hair and fingernails; the fringed plates hang from the upper jaw and strain krill from mouthfuls of water.

About how long were the upper canines of the largest Smilodon species?

Smilodon populator's upper canines reached about 28 cm including the root; they were slender and fragile, adapted for precision killing rather than crushing.

In what year was the American Dental Association established?

The American Dental Association was founded in 1859 by 26 dentists meeting at Niagara Falls, New York, and passed 159,000 members in the 2010s.

Which actor plays the torturing dentist Christian Szell in Marathon Man?

Laurence Olivier's Szell drills into Dustin Hoffman's Babe without anesthetic while asking 'Is it safe?'; the role earned Olivier a 1977 Oscar nomination.

Who plays sadistic, nitrous-addicted dentist Orin Scrivello in Little Shop of Horrors (1986)?

Steve Martin's Orin Scrivello is florist Audrey's abusive boyfriend and gets his own number, 'Dentist!', before dying of his own laughing gas.

Xylitol, the tooth-friendly sweetener, is nicknamed after which tree it can be extracted from?

Xylitol is nicknamed 'birch sugar' because it was long extracted from birch bark; Emil Fischer first isolated it from beech chips in 1890, and it is toxic to dogs.

Who is believed to have made the first mass-produced toothbrush, in Britain in 1780?

William Addis hit on the idea in Newgate prison, deciding a rag with soot and salt was ineffective; he drilled a bone, tied in bristles, and his firm outlived him as Wisdom.

At roughly what age does teething, the eruption of the first baby teeth, typically begin?

Six months is the typical start, and primary teeth keep arriving until about 25 to 33 months.

Which Arctic mammal uses its long canine tusks to haul itself onto ice?

The walrus's tusks are upper canines up to a metre long, used to haul out onto ice and to fight; its genus name Odobenus means 'tooth-walker'.

Who made the first porcelain dentures, around 1770?

Alexis Duchâteau, a Paris apothecary, had porcelain dentures fired in 1774 to replace his own foul-smelling ivory set, helped by dentist Dubois de Chémant, who later patented the idea.

The oral irrigator maker Waterpik began in 1962 under what corporate name?

Aqua Tec Corporation was the name Fort Collins dentist Gerald Moyer and engineer John Mattingly used in 1962; the firm was renamed for its product and bought by Church & Dwight in 2017.

Hominin remains bearing 'toothpick' lesions from about 1.8 million years ago were found in which country?

The Dmanisi jaw from Georgia shows grooves worn by a toothpick 1.8 million years ago; a Neanderthal from Cova Foradà in Spain used one to ease gum disease.

In the 17th century, toothpicks were treated as what?

Seventeenth-century toothpicks were jewel-set luxury objects of gold or silver kept in cases; Romans had favoured mastic-wood picks, and delicate silver examples survive from antiquity.

Evidence of dentistry using bow drills around 7000 BCE comes from which ancient civilisation?

At Mehrgarh in the Indus Valley, skilled bead craftsmen may have operated the bow drills, cutting holes 3.5 mm deep with concentric grooves in eleven molars.

In which year was the first electric dental drill patented?

George F. Green patented the first electric dental drill in 1875; by 1914 electric drills reached 3,000 rpm, and modern air-turbine handpieces spin hundreds of thousands of times a minute.

The contra-angle air-turbine handpiece was invented by John Patrick Walsh's team in which country?

John Patrick Walsh's team at the Dominion Physical Laboratory in Wellington, New Zealand built it in 1949; the angled shaft lets the spinning burr reach the mouth's less accessible corners.

Which chemical is the active ingredient in most tooth-whitening products?

Hydrogen peroxide oxidises the stain molecules in enamel; it is often delivered as carbamide peroxide, a stable complex that releases it on contact with water.

In which sport did the mouthguard originate?

Early boxers clenched cotton, sponge or bits of wood until British dentist Woolf Krause began making proper mouthpieces.

Which 1947 innovation by Los Angeles dentist Rodney Lilyquist let athletes talk normally while protected?

Lilyquist's transparent acrylic splint was molded to fit over the upper or lower teeth, thin enough for normal speech and a big improvement on the thick guards boxers wore.

Cheap denture bases from the 1850s were moulded from which material?

Vulcanite dentures were hardened rubber, Charles Goodyear's vulcanised rubber moulded around porcelain teeth; acrylic resin replaced it as the main denture material from the 1940s.

Which two bacteria are blamed for the plaque behind periodontitis?

Porphyromonas gingivalis and Treponema denticola anchor the 'red complex' of periodontal pathogens; periodontitis is the main cause of adult tooth loss, affecting an estimated 538 million people in 2015.

In which US state did Alfred Fones open the first school for dental hygienists in 1913?

Fones's school in Bridgeport, Connecticut trained hygienists from 1913; his cousin Irene Newman received the world's first dental hygienist licence there in 1917.

Baby teeth are formally called deciduous teeth, a word more often used for which living things?

Trees that shed leaves each autumn share the label because deciduous means falling off once a part is no longer needed. Antlers that deer drop every year earn the same word.

For children aged three to six, the NHS advises using an amount of toothpaste the size of what?

A pea is the NHS measure for ages three to six, while children under three get only a smear. From seven most children can brush alone, though parents are told to keep watching.

US pediatric dentists want a child's first visit soon after the first tooth, or by which milestone?

Turning one is the deadline shared by the American Academy of Pediatrics and its dental counterpart. Parents leave with a home-care plan plus advice on diet and preventing mouth injuries.

Which anatomical name belongs to the lower jawbone, the skull's largest and only movable bone?

The mandible begins as two halves that fuse at the chin during the first year of life. It hinges on the temporal bones, just in front of each ear.

Which word names the fear of dental care that keeps sufferers away until pain forces a visit?

Odontophobia, also called dentophobia, is eased with methods ranging from music therapy and guided imagery to conscious sedation. With children, dentists often use a routine known as tell-show-do.

Which university introduced the DMD dental degree because it granted its degrees only in Latin?

Harvard found that the Latin for the existing dental title would not shorten to DDS. After consulting a Latin scholar it adapted the wording of its medical degree instead, and the DMD was born.

The sharp hooked instrument a dentist runs over teeth to feel for flaws is called a dental what?

Explorer is the formal name, though many patients know it as the sickle probe. Its fine tip carries vibrations to the handle, so the dentist can feel irregularities too small to see.

Josiah Flagg built the first dental chair by adding a headrest to which style of wooden seat?

Windsor was the style, a plain wooden seat that Flagg upgraded with an adjustable headrest plus an arm extension to hold his instruments.

Which calcified tissue covers the root of a tooth and anchors the fibres that hold it in the jaw?

Cementum is light yellow and keeps forming throughout life. Fresh layers are laid down so the tooth's attachment stays intact as the older surface ages.

Which term describes upper and lower teeth that fail to meet properly when the jaws close?

Malocclusion, in Edward Angle's definition, is any deviation of the bite from the ideal. A childhood diet of soft, cooked food is among the suspected causes, because the jaws then grow smaller.

Which part of fixed braces threads through every bracket and supplies the force that moves teeth?

The archwire is tied into each bracket with small ligatures, which come in colours the patient can choose. Orthodontists bend and tighten it at check-ups to steer the teeth.

What do orthodontists call the small bands hooked from upper to lower braces to fix a bite?

Elastics come in many strengths and were pioneered by Calvin Case and Henry Baker. The Class II kind runs from a lower back tooth to an upper eye tooth.

Which childhood habit can tip front teeth outward and cause an open bite once adult teeth arrive?

Thumb sucking does no harm in toddlers, and most children give it up by themselves between two and four. Any damage is reversible if the habit ends before the permanent teeth arrive.

The word orthodontist pairs the Greek for 'tooth' with a Greek word that carries which meaning?

Straight is the core sense of the Greek orthos, which can also mean true or correct. English borrowed the older form orthodontia in 1849.

America Ferrera's title character is known for her adult braces in which ABC comedy-drama?

Ugly Betty kept its heroine in braces until an episode titled Million Dollar Smile. The series was based on the Colombian telenovela Yo soy Betty, la fea.

Clear ceramic braces use a material developed with which agency for heat-seeking missile trackers?

NASA worked with the company Ceradyne on translucent polycrystalline alumina, made to protect the infrared antennae of missile trackers. Its see-through toughness suited so-called invisible braces.

Alginate, the paste orthodontists use to take moulds of teeth, is refined from which natural source?

Seaweed supplies alginate, which also thickens drinks and ice cream. A single species used, giant kelp, can grow 20 to 40 metres long.

Mewing, a jawline craze named after orthodontist John Mew, centres on the resting position of what?

The tongue, in Mew's theory, widens the upper jaw simply by resting in the right place. Reviewers have found inadequate evidence that the do-it-yourself method works.

Nickel-titanium braces wires go limp when cold but spring back at body heat, a property called what?

Shape memory lets an orthodontist thread a chilled, floppy wire through crooked brackets with ease. Once warmed by the mouth it stiffens and seeks its original curve, pressing lightly and constantly.

Braces work because steady pressure prompts which cells to clear bone from a moving tooth's path?

Osteoclasts take their name from the Greek for 'bone' and 'broken', and they digest bone by secreting acid and an enzyme. A related cell eats away the roots of baby teeth before they fall out.

Invisalign founders Zia Chishti and Kelsey Wirth met at the business school of which university?

Stanford classmates Chishti and Wirth founded Align Technology in 1997 and began developing a clear aligner. Chishti was ousted from the company in 2002.

Which bite problem is a sideways mismatch, with a tooth set further in or out than its partner?

Crossbite is a lateral misalignment of the two arches. In a child who still has baby teeth, it may come from the teeth themselves or from the way the jaw bones have grown.

Traditional 'train track' braces use which alloy, a problem for patients allergic to its nickel?

Stainless steel contains nickel, so allergic patients are often fitted with gold-plated or titanium braces instead. The titanium kind is lighter and just as strong, but costs more.

Which Roman medical writer first recorded straightening a tooth by regular pressure from a finger?

Celsus compiled the encyclopedic De Medicina, the only surviving section of a much larger work. Earlier still, Hippocrates and Aristotle had pondered ways to straighten teeth.

Which technical term describes jaw surgery for bite problems too severe for braces alone?

Orthognathic surgery is also a highly successful treatment for obstructive sleep apnoea. It often includes braces before and after the operation.

C. Loring Brace argued that Europeans developed an overbite only after adopting which eating tools?

Knife and fork moved the cutting onto the plate, where before diners clamped meat in their teeth and sliced off a piece. Among Chinese diners, Brace linked the same change to chopsticks, 900 years earlier.

Which word do orthodontists use for the tendency of straightened teeth to drift back out of line?

Relapse is a lifelong risk, driven by the recoil of stretched fibres around the roots, pressure from the surrounding soft tissues and continued growth. A holding appliance after braces guards against it.

Norman Kingsley, a 19th-century pioneer of orthodontics, also practised which art form?

Sculpture sat alongside writing among Kingsley's talents. His soft-rubber artificial palates let patients born with a cleft palate speak and eat normally.

Dentists chart the mouth in upper and lower, left and right sections, each known as what?

A quadrant is one quarter of the full set of teeth. When a tooth is to be pulled, dentists may write it in two notations at once, so the wrong one is less likely to come out.

In the tooth numbering used by US dentists, which numbers mark the two upper front teeth?

8 and 9 fall in the middle because the count starts at the upper right wisdom tooth and runs across to the upper left. Dentists in most other countries use a different, two-digit code.

After the upper row, the numbering used by US dentists resumes on the bottom jaw at which position?

Lower left wisdom tooth is number 17, because the count drops directly down from where the top row ended. It then runs back along the bottom jaw to finish at the lower right.

In the chart used by US dentists, adult teeth get numbers while a child's first teeth get what?

Capital letters run from A at the upper right round to T at the lower right. Every tooth, in either set, therefore carries a label that no other tooth shares.

The American Dental Association dropped Palmer notation because its symbols were awkward on what?

Keyboards could not produce Palmer's corner-bracket marks, so in 1968 the association backed a chart of plain numbers and letters instead. It had recommended the Palmer method as recently as 1947.

In two-digit FDI dental notation, what does a first digit from 5 to 8 always signal?

A baby tooth takes a first digit from 5 to 8, while the four sections of adult teeth use 1 to 4. The scheme was developed by the FDI World Dental Federation and is used in most countries.

Palmer's corner-bracket tooth notation outlasted newer codes among dentists in which country?

United Kingdom orthodontists, students and practitioners still overwhelmingly preferred it in 1998, long after most of the world had adopted a two-digit code. It is named for Ohio dentist Corydon Palmer.

Palmer notation counts teeth outward from the midline, so every wisdom tooth gets which number?

8 marks all four wisdom teeth on a Palmer chart, since each corner of the mouth is counted separately, starting from 1 at the front. A small corner bracket beside the number shows which corner is meant.

FDI codes open with a digit for the mouth corner, so which code marks the upper right front tooth?

11 joins a 1 for the patient's upper right with a 1 for the tooth nearest the midline. The system is also published as an international standard, ISO 3950.

Dental charts are drawn from the dentist's viewpoint, so a patient's right appears on which side?

The left of the chart shows the patient's right, just as a dentist sees it when facing the chair. Labels such as 'upper right' always refer to the patient's own right.

Which mild, reversible form of gum disease causes redness and bleeding but no loss of bone?

Gingivitis clears up with good oral hygiene, but left untreated it can progress to periodontitis, in which the tissue and bone around the teeth are destroyed.

Which habit is a major risk factor for periodontitis, tied in studies to more bone and tooth loss?

Tobacco smoking not only raises the odds of gum disease but can also interfere with its treatment. Quitting has been shown to improve the health of the gums.

Which chronic condition raises the risk of gum disease and is in turn made harder to control by it?

Diabetes and gum disease feed each other, because the constant inflammation from infected gums makes blood glucose harder to balance.

Which dental specialist treats disease of the gums and supporting bone and also places implants?

Periodontist comes from Greek words meaning 'around' and 'tooth', a nod to the supporting structures the specialty studies.

The phrase 'long in the tooth', meaning old, refers to the receding gums of which ageing animals?

Horses are thought to be the source, since their gums recede with age and make the teeth look longer. Their teeth are such a good guide to age that inspecting a gift horse's mouth was considered rude.

Advanced gum disease loosens teeth by slowly eating away which structure that holds their roots?

Alveolar bone forms the sockets that anchor the teeth, and its loss to periodontitis is essentially irreversible. Gum disease is considered the main cause of tooth loss in adults worldwide.

Dentists track periodontitis with a blunt probe that measures the depth of what around each tooth?

Gum pockets deeper than about 3 mm suggest that the gum's attachment to the tooth is being lost. The 'deep' in a deep cleaning refers to them.

Which non-surgical treatment for gum disease is popularly known as a deep cleaning?

Scaling and root planing first scrapes hardened deposits from below the gumline, then smooths the exposed root surfaces. An ordinary cleaning skips that second step.

Which mouthwash antiseptic eases mild gum inflammation but can stain teeth after four weeks of use?

Chlorhexidine also turns up in skin disinfectants, wound dressings and eye drops. Newer rinses add chelated zinc so that they stain less.

Gum disease was once known as Riggs' disease after John Riggs, dentist to which American author?

Mark Twain was a patient of Riggs in Hartford, where the dentist was the first to limit his practice to treating the gums. Riggs scraped deposits from the teeth with instruments he designed himself.

George Washington's dentist John Greenwood built the first dental foot engine from his mother's what?

Spinning wheel treadles already turned a wheel by foot, so Greenwood adapted his mother's to rotate a drill. His father, Isaac Greenwood, was a dentist too.

Which jaw muscle, found only in mammals, is the most obvious of the four muscles used for chewing?

The masseter is one of the strongest chewing muscles and lies closest to the surface. It is particularly powerful in herbivores, which need it to grind plant matter.