1 anthropology

2Varun Malhotra, Department of orthodontics , Bapuji Dental College and Hospital

Table Of Contents

IntroductionWhat Is Anthropology.Importance and the purpose of Life Studies(Anthropology)Classification of Anthropology

Physical AnthropologyCultural AnthropologyLinguistic AnthropologyArcheology

Evolution The Various Eras of Evolution.

Theories of Evolution Homonidae Evolution Process Evolution of Human Face Evolution of the jaw and joints Evolution of teeth and its attachment apparatus

Conclusion: Future :Where is it all leading us leading us

Concept of Attritional Occlusion Carabelli Trait

Anthropology is the broad scientific study of humankind’s differences, cultural and biological, against the background of the nature all humans

share around the world and throughout time.

hat Is the Importance and the purpose of Life Studies

(Anthropology)

The fundamental questions addressed by anthropologists are

"What does it mean to be human?" and

"How did we become human?"

Included in anthropology are four main subdivisions:

Physical Anthropology

Cultural Anthropology

Archaeology

Linguistic Anthropology

Physical AnthropologyInvolves mechanisms of biological evolution, genetic

inheritance, human adaptability and variation, primatology, and the fossil record of human evolution.

Cultural AnthropologyBranch of Anthropology that deals with Culture,,

subsistence and other economic patterns, kinship, sex and marriage, socialization, social control, political

organization, class, ethnicity, gender, religion, and cultural changes .

Linguistic Anthropology

The human communication process focusing on the importance of socio-cultural influences; nonverbal

communication; and the structure, function, and history of languages and dialects

Archaeology

Prehistory and early history of cultures around the world; major trends in cultural evolution; and techniques for finding, excavating, dating, and analyzing material

remains of past societies.

Prokaryotes&

Eukaryotes

Ocean Species Rapidly Diversify

Primitive Fishes, Corals,

molluscs

MostInvertebrates

& FewVertebrates

FISHES CRABS

AND AMPHIBIANS

Reptiles, giant Insects

AppearInsects,

Reptiles spread,Trilobites die

Dinosaurs,Insects thrive.Birds appear

Mammals,Spiders flourish

Primates appear

Humans Thrive ManySpecies die

Dinosaurs die out Birds

thrive

Dinosaurs,Mammals

Marine reptilesappear

When an organism

Darwin and HMS BeagleIn 1835 the British naval ship Beagle reached the Galapagos Islands off South America's west coast. There, a young biologist named Charles Darwin collected samples of the plants and animals and took notes of his observations. Darwin was awed by the enormous variety of life inhabiting these islands and concluded that life must be ever changing, or evolving, to create such diversity. Upon returning to England, Darwin spent 20 years studying his Galapagos Islands samples and notes.

He observed variations among local populations of a species and saw that local conditions acted to select

the traits that enabled one population of the species to survive better than another. He decided that it was in this way, through the process of natural selection by the environment, that evolution occurred. In 1859

Darwin published his conclusions in the book On the Origin of Species by Means of Natural Selection.

.Albino fish are easy targets

A large number of trout and salmon fish born in artificial breeding farms are white (albino), yet it is nearly impossible

to find an albino trout or salmon fish in the wild. Normal rainbow trout are striped and spotted with various shades of

brown and yellow. To a heron or kingfisher,these colours look much like the bottom of a stream, making it difficult for the bird to spotted fish. Albino fish below the water , which

are white, are easy for the waterfowl to spot and rarely survive long enough to produce offspring.

Pollution and Natural SelectionIn the 1800’s pollution in the English cities enabled natural selection to operate on a group of peppered

moths .When industrialization began most peppered moths were pale with black splodges which gave them the appearance of lichen on tree barks ,hiding them

from the predators .Only a few moths were dark. Soon, soot from the factories turned the city trees and

buildings dark brown these pale moths became visible to the birds .Within few years ,dark moth became common in cities, and speckled form prevailed in

cleaner countryside.

..Theory of Orthogenesis

(Development in Straight Line)

Haldane and Julian Huxley say that evolution proceeds in any particular direction only ,not because of any

advantage gained by the race ,or because of any direct molding effect of surrounding, but because of some

inner urge ,some necessity for the hereditary constitution to change in just that particular way.

"The affinities of all the beings of the same class have sometimes been represented by a great tree... As buds give rise by growth to fresh buds, and these if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications."

The first humans survived by scavenging, gathering, and huntingEarly scavengers

and hunters may have depleted populations of some of their

prey and some competing carnivores

The human branch of the primate tree is only a few million years old

Apes and hominids probably diverged from a common ape-like ancestor

This occurred between 5 and 7 million years ago

The earliest hominids were a diverse group

Various species of Australopithecus date from about 4 to 1 million years ago

Our own species, Homo sapiens, is the only hominid that has not become extinct

Upright posture evolved well before our enlarged brain

Australopithecines had relatively small brains This indicates that bipedalism preceded the

evolution of the enlarged brainBipedalism is a basic human trait.

Homo and the evolution of larger brains Homo habilis, an early African hominid, coexisted with

some of the australopithecines.They had larger brains and made simple tools

They may also have given rise to the more advanced Homo erectus

Homo erectus spread out of Africa over most of the Old World. They eventually gave rise to Homo

sapiens

When and where did modern humans arise?

One of the regional descendents of H. erectus was the stocky and muscular Neanderthals

They lived throughout Europe from about 200,000 to 40,000 years ago

Some paleoanthropologists think that modern humans arose from the regionally diverse populations of

archaic Homo sapiens in Africa, Europe, and Asia.Others believe that modern Homo sapiens came from

a second group in Africa. This group arose around 100,00 years ago. They migrated out of Africa

They replaced regional populations of archaic peoples

Major milestones in the evolution of Homo sapiens are the evolution of an erect stance, a large brain a

prolonged period of parental care. We have not changed much biologically since modern humans first appeared.

Our culture —the accumulated knowledge, customs, beliefs, arts, and other products—has evolved enormously

There have been three main stages in cultural change

Scavenging-gathering-hunting was the first major stage of culture

The first humans survived by scavenging, gathering, and hunting

Early scavengers and hunters may have

depleted populations of some of their

prey and some competing carnivores.

Agriculture was a second major stage of culture

Agriculture arose about 10,000-15,000 years ago.

People settled down and began growing food and domesticating animals

The machine age is the third major stage of culture

The Industrial Revolution began in the 1700sIndustrialization brought a change from hand production to energy-intensive, large-scale machine production

Anthropometry is a division of anthropology, it has been described by Hrdlicka as the systemized art of

measuring and taking observations on man ,his skeleton, his brain or other organs, by the most reliable means and

methods and for scientific purposes.Measurement of the form and relationship of the

components of the head , particularly the jaws and especially the teeth are sufficient to differentiate

between the ape and man .

Craniometry is a subdivision of anthropometry,has been an important study in orthodontic research, because

orthodontics is concerned primarily with the correction of morphologic deviations from the accepted norms in

dentofacial area. Measurements of the extent of these deviations entails some knowledge of physical

anthropology and the ability to recognize and use the anthropologic landmarks.

Lucy, Australopithecus

aferensis, lived about 3.2 million years ago in what is

now Hadar, Ethiopia.Lucy's limbs reveal upright

walking to be a very old habit. Lucy came to life in late 1974,

when anthropologist Don Johanson was fresh out of

graduate school and working in the badlands at Hadar.

A mandible and partial postcranial skeleton of a single individual was found in 1994. Analysis and publication on this find has yet to be made. Once completed, this should provide significant insight

into the positional repertoire of Ardipithecus ramidus, dispelling all doubt as to whether or not this truly was a bipedal hominid.

Though not recognized as such for 30 years, the first Australopithecus anamensis discovery

occurred in the Kanapoi region of East Lake Turkana in 1965 by a Harvard University

expedition.

The species A. Afarensis is one of the better known australopithecines, with regards to the number of

samples attributed to the species. The species was named by D. Johanson and T. White in 1978.

Very little is known about Australopithecus aethiopicus, since so few specimens have been attributed to the species, but the features that are known provide important insights into the

possible evolutionary history between the robust and gracile australopithecines.

The africanus material is seen as different things by different people. Some see this as a regional variation or subspecies of

afarensis, some see it as two completely different species, and some consider the africanus material to be the descendants

of afarensis.

The discovery of the specimen OH 5 ("Zinj") of this species in 1959, by

Mary Leakey, was a watershed in the history of paleoanthropology.

In January 1964, the team announced the new species Homo habilis. The name was

suggested by Raymond Dart, and means "handy man," in reference to this hominids

supposed tool making prowess.

As a general rule of thumb, one can consider most attributed ergaster specimens to be early

erectus geographically confined to Africa

Homo ergaster is one of the more problematic of somewhat accepted species designations currently tossed around in anthropological literature. Each individual researcher that sees ergaster as a valid taxon ( in biology, a term used to denote any group or rank in the classification of organisms, e.g., class, order, family sees different specimens as belonging or not belonging to the taxon.)

Many researchers deny any validity to the species at all. On the whole though, most researchers see too little difference between ergaster and erectus to form the basis of a species of the former, separated from the latter.

One of the most important erectus specimen is the Nariokotome Boy, KNM-WT 15000. This specimen was discovered by a team led by R. Leakey and A. Walker at Nariokotome, Kenya, in 1984. This is the most complete early human skeleton ever discovered.

The beginning of paleoanthropology as a scientific discipline began on an August day in 1856. On that

day the specimen that was to become known as Neanderthal 1 was discovered in the Feldhofer

grotto, in the Neander Valley, Germany.

Broad, vertical, flattened, enveloped by an enormous balloon-shaped cranium with a bulbous forehead

overhanging tiny, retrusive jaws, a small mouth, a chin, and the curious vestige of a narrow fleshy snout—an owl-

eyed face showing changing expressions.

If u have not already guessed it this is the human face for you

Although somehow beautiful to our eyes, this has to be an "odd" design by ordinary

mammalian standards

There have been many theories over the years; but regrettably, we may never know for sure what the primary

factors were that initiated the long evolutionary chain of interrelated adaptations throughout the whole body that

relate to the many design features of our facial heritage. We can, however, partially explain the anatomic,

developmental, and functional meaning of each factor in this series of mutually dependent changes.

Concept 1Man is one of the few truly bipedal mammals. Our upright posture

involves a great many anatomic and functional adaptations throughout every part of the body, and no one of these would work without all the others. We have "feet," and the human foot stands

by itself, as it were, as a unique anatomic feature of man.

The designs of the toes, foot bones, arch of the foot, ankle, leg bones, pelvis, and vertebral column all

interrelate in the anatomic composite that provides upright body stance

The head is in a balanced positionon an upright spine. The arms and

hands have become freed. The manipulation of food and other

objects and defense, offense, and so forth, utilize primarily the

hands, rather than the shortened jaws.

The enormous enlargement and the resultant configuration of the brain have caused a "flexure"

(bending) of the human cranial base. This relates to two key features.

First, the spinal cord is aligned vertically, a change that permits upright, bipedal body

stance with free arms and hands.

Second, the orbits have undergone a rotation in conjunction with frontal lobe expansion. This aligns them so that they point in the forward

direction of upright body movement. The body has become vertical, but the neutral visual axis is thereby still horizontal, as in other mammals.

(Note: The muzzle of a typical animal points obliquely downward in the "neutral" position, not straight forward. This positions the orbital axis

approximately parallel with the ground and toward the direction of body movement.)

The cranial base of the typical mammal is flat, in contrast to the human cranium, and the spinal cord passes into a

horizontally directed vertebral column.

The head is in a balanced position on an upright spine. The arms and hands have become freed. The

manipulation of food and other objects and defense, offense, and so forth, utilize primarily the hands,

rather than the shortened jaws.

The large size of the human brain also relates to a rotation of the orbits toward the midline . This results in a binocular

arrangement of the orbits, a feature that complements finger-controlled manipulation of food, tools, weapons, and so forth. The absence of a long, protrusive muzzle does not

block the close-up vision of hand-held objects. The human mind directs the free hands that can work with three-dimensional perspective in an upright stance on feet.

Complete orbital rotation into a forward-pointing direction, however, has also caused a marked reduction in the

interorbital part of the face. This is significant, because the area involved is the root of the nasal region, and the result of man's close-set eyes is a narrow & necessarily quite short nose. The olfactory sense in Homo has become a much less

dominant factor in environmental awareness and is far exceeded by many other mammalian groups

Reduction in nasal protrusion is accompanied by a more or less equivalent reduction of the jaw (nasal reduction

apparently paced this evolutionary process). The whole face has necessarily become reduced in horizontal length as a result. However, the face has also been rotated into a nearly vertical alignment in relationship to the massive enlargement of the brain and the flexure of the cranial

The whole face has necessarily become reduced in horizontal length

The nasal mucosa is ordinarily an active site involved in temperature regulation in most mammals. Vasoconstriction

and vasodilation of the vessels in the massive spread of mucosa covering the turbinates control the amount of heat

retention or loss. Because of marked nasal reduction in man, however, this function has been largely taken over by the relatively hairless and sweat gland—loaded integument.

Control of blood flow in the dermis, combined with sweat gland activity, provides the equivalent for nasal

thermoregulation. This is possible in man (and in a very few other species, such as the pig) because of a near-naked

In thick-furred animals, thermoregulation is carried out by regulating heat transfers in the nasal mucosa, panting to release excess heat, limited perspiration in hairless areas (such as the pads of the paws), and a Huffing of the fur to increase dead air insulation.

All mammalian forms have reinforcement "pillars" built into the architectonic design of the craniofacial complex. These pillars are parts of bones that provide a buttress for structural support and biomechanical stress resistance that

balances the physical properties of the skull against the composite of forces acting within it, including growth

itself, just as the framework of a building provides generalized support and stability

Although customarily described with reference to tooth positions, the nature of support goes well beyond just

accommodation to masticatory forces. In the human face, one of these is the "key ridge," which is a vertical column of thickened maxillary bone approximately centered above

the functionally important area around the upper first molar.

Mechanical support then continues from this ridge into and through the lateral orbital rim on to the

supraorbital-reinforced frontal bone.

The second maxillary molar is reinforced by a vertical sheet of bone, the posterolateral orbital wall, which

extends directly above this tooth

The human face is exceptionally wide because the brain and cranial floor are wide. However, the face has been almost engulfed by the massive brain behind and above it. Note the wondrously, incredibly colossal size of the human cranium, in comparison with that of the typical

mammal.

The expanded frontal lobes of the human brain lie above the eyes and almost the whole remainder of the face,

rather than behind, and a forehead has thus been added. This also relates to the rotation of the orbits into vertical, forward-facing positions as well as to the rotation of the

face as a whole into a downward-backward position.

The expansion of the various parts of the cerebral hemispheres has created sizable pockets in the

cranial floor). Each of these endocranial fossae relates to specific lobes of the brain on the inside of

the cranial floor and to specific parts of the face, pharynx, and so forth, on the outside. We can utilize

our knowledge of these brain-cranial floor-facial relationships to advantage in analyzing the structure of the face and the basis for its many variations in

form and pattern.

The first documented vertebrates were called Agnatha. They are minute fish like animals without jaws. The evolution of vertebrates started with the

expansion of mouth cavity and disappearance of one or two anterior gill arches. The early jawed

vertebrates were called placodermi.

The vertebrate with jaws are divided into five classes: Fishes ,amphibians, reptiles, birds and mammals. Until

the evolution of mammals, the vertebrate mandible consisted of several dermal bones which articulate with

the skull at a joint formed by two enchondral bones derived form the cartilage bars of the first brachial arch.

In mammal only one dermal bone ( the dentary) is retained as the mandible.

A variety of evidence supports this concept. The gradual appearance of such a bony process on the mandible can be seen in a fossil series of related reptilian skulls. A similar

sequence occurs in the embryonic development of the temporomandibular joint in man and all other mammals studied. The articular tissue of this joint originates in a

very different manner from that seen in the usual synovial joint.

The bony homologues of the jaw joints and related structures in reptiles and mammals are shown in table Within the class of mammals , parallel evolution in the

temporomandibular joint , producing marked differences in form and function as the jaws became specialized .

shearing (lion), grinding (cow), grasping (porpoise),and biting and chewing (man).

Among the modern vertebrates only the Class Aves (birds) lack teeth. Two types of conditions prevail

among the tooth bearing vertebrates. The so called lower vertebrates (bony and cartilaginous fishes,

amphibia is, and reptiles generally are characterized by polyphyodontia, whereby teeth are continually

being replaced by successors. Mammals, on the other hand, may be either monophyodont, or diphyodont

Varun Malhotra, Department of orthodontics , Bapuji Dental College and Hospital

In the former condition there is but one set of teeth which has no successors, in the latter there are two sets, one being the primary or deciduous dentition, the other

the secondary or permanent teeth. Certain insectivora are monophyodont, but most mammals are diphyodont.

The lower vertebrates are homodont, a condition typified by teeth which are alike, while mammals are

heterodont in that there are various kinds of teeth in the same dentition

The morphology of the teeth quite accurately reflects the functions they subserve within the species.

Among mammals these functions include: piercing. tearing, trapping, digging, combing, scraping, grinding, crushing, and shearing: These varying properties may aid the animal in fighting, obtaining food, and securing

a mate.

Since the teeth are placed in the most anterior part of the animal, well in front of the brain and the

eyes, they, along with the olfactory organ make the first contact with the environment and are hence of primary importance for survival. Few animals

can sustain in the wild state if their teeth were much less than typical for the species.

Since there is a high correlation between tooth form and its function, it is possible for the paleontologist in many cases to describe quite accurately much of the life habits

of a prehistoric animal from a study of the fossil teeth alone.

EvolutionAbout 250,000,000 years ago the first, or stem, reptiles evolvcd. They are called Cotylosaurs and they gave rise to a group of reptiles, the Synapsids, which dominated

life on earth for perhaps fifty or sixty million years. Two successive radiations took place among the Synapsids, one originating from a group known as the Pelycosaurs

and giving rise to a reptilian series called Sphenacodotiia.

The latter, in turn, gave rise to the Therapsids, which flourished in Permian times and which included among

its various types flesh-eating reptiles known as Theriodonts.

250,000,000 years ago the first, or stem, reptiles evolvcd. They Were called Cotylosaurs

Synapsids, which dominated life on earth for perhaps fifty or sixty million years

Pelycosaurs

And giving rise to a reptilian series called Sphenacodotiia.

Radiation from the Theriodontia produced the Cynodonts, probably the first mammal-like reptiles. It is from the Cynodonts

that many types of mammals originated.

gave rise to the Therapsids, which flourished in Permian times and which included among its various types flesh-

eating reptiles known as Theriodonts

EVOLUTION OF HUMAN MOLAR TEETH :Six main theories have been advanced to explain the evolution of the complicated multiple-cusped teeth of mammals, including man, from the simpler teeth of reptiles.1) Concrescence theory2) Cingulum theory 3) Kinetogenetic theoiy4) Tritubercular theory

5) Multitubercular theory6) Dimer's theory

Concrescence theory :

Ameghino, Rose and Kekenthal were all with the opinion mammalian teeth were developed from simpler cones (Haplodont teeth) and the modern multiple -cusped teeth are formed by the fusion of 2 or more of these simple haplodont teeth into a compound tooth.

Cingulum theory :In this theory- mammalian teeth are derived from haplodont teeth.

"Marrett Tims" considered that basal ridge or cingulum, which surrounds a tooth at its neck, develops into a fresh cusp or cusps- which explains to a great extent the evolution of complex tooth

form."Osborn" says that, by the elevation of cingulum ino prominence and its disappearance in others - regarded as the mother of cusps."Mummery" states that it would certainly appear that accessory

cusps arises from the cingulum..

Kinetogenetic theory :Ryder, who upholds this theory, again regards the earliest mammalian teeth as haplodont in origin.

He mentioned that the movements of TMJ. govern the form of the tooth. The simple cones become flattened by mutual pressure, and the ridge and hollows are produced

by the movements of the lower jaw in mastication.

There is definite relationship between the form and movement of the condyle and the forms of teeth.

Many authorities admit, this connection between tooth form and movement of condyle but consider that Ryder's

view of it is the exact reverse of the true sequellae . They mention and that the shade and movement of the joint are modified and formed by the diet and by the

shape of the teeth.

S. Glasstone removed the tooth germs from the embryos of rats and rabbits and grew them in vitro. As there is no

TMJ movement here to effect the forms of teeth. Therefore, the factors responsible for the morphology of

the tooth are intrinsic to the tooth germ and Glasstone found that rats and rabbits tended to develop extra cusps

when grown in vitro.

Tritubercular theory or Cope - Osborn Theory

This theory, 1st advanced by Cope and later elaborated by Osborn, sometimes called the "Cope-Osborn theory". He

considered that multicuspid mammalian teeth are developed from a simple haplodont or reptilian form of tooth by the addition of extra cusps.triconodont teeth.

In this theory - original haplodont cone is known as the PROTOCONE when this original cone has two small

accessory cones on .its mesial and distal surface and it is known as PROTODONT TOOTH.

These small accessory cones develop in size until the tooth appears to consists of 3 cones in a straight line and

this is known as TRICONODONT TEETH.

The anterior cusp - paracone - upper teeth- paraconid - lower teeth

The large middle cusp - protocone - upper teeth - protoconoid - lower teeth

The posterior cusp - metacone - upper teeth

- metaconid - lower teeth

Owing to shortening of jaws, these triconodont teeth are said to be compressed anteroposteriorly until the cusps form a

triangle instead of straight line.

In upper teeth Protocone is squeezed to the lingual side to form the large anterior lingual cusps while the paracone and

the metacone are squeezed to buccal side.In lower teeth

Protoconid is forced to the buccal side to form anterior buccal cusp and paraconid and metaconid

are forced to lingual side,

In certain teeth, owing to the diet, some cusps of the TRIGON are lost and replaced by cusps from the

additional part known as the TALON. Which it crushing or masticating element of the tooth and developed from

the enlargement of cingulum.In human upper molar, which has 4 cusps, all 3 cusps is of

trigon and cingulum has developed into a 4th cusp. (Hypocone) behind protocone

In lower molar, which has 5 cusps, the paraconid is lost and the metaconid slips forward to take paraconid

position.Only 2 cusps of trigon remain - protoconid and metaconid and additional 3 cusps, hypoconoid, entaconid and hypoconolid belong to the talon.

Human premolars are said to derive - lingual cusps - by development of cingulum.

Leche, Taeker, Rose studying tooth germs from the embryos of marsupials, ungulates and man, agreed

that the 1st cusp to be. developed is the PARACONE.

Woodward, says that anterior BUCCAL CUSP is the 1st to develop in both upper and lower jaws.

Multitubercular (or polybuny) theory :- Forsyth Major, refutes the statement that the 1st

mammalian tooth can be traced back to a simple haplodont or a tritubercular tooth. He considers that the 1st

molariform tooth was a multitubercular tooth and the tritubercular tooth is derived from an earlier form which

was multitubercular.

Forshyth Major considers that human molars and modern mammalian molar (whether tritubercular or not) are derived from multitubercular teeth by reduction in

the number or tubercle.

Dimer theory :

It is the result of investigation by Prof. Bolk of Amsterdam and advances the view that there is one origin for all mammalian teeth, whether, incisors,

canine, premolars or molars.

He agrees with the concrescence, kinetogenetic andcingulum theories and differs from the tritubercular theory,

which explains evolution of premolar and the talon of molar in one way and the trigon of molar in another.

Bolk's views are expressed under 4 headings :

Hypothesis of triconodonty The hypothesis of dimery

Hypothesis of concentration Hypothesis of equivalence

Hypothesis of triconodonty –

He affirms that, mammalian teeth are evolved from a triconodont teeth, not a haplodont with one large and 2

small cusps in a straight line antero posteriorly..

THE HYPOTHESIS OF DIMERY :- Every mammalian tooth is homologous with two

reptilian tooth.- The labial and incisal portion of the incisors, canines

and buccal cusps of premolars and molars - one series of reptilian teeth.

- Cingulum of incisors, canine and lingual cusps of premolars and molars represent a second or later series of

reptilian teeth.-

Each longitudinal half of human tooth Monomere the buccal half. Protomere and The lingual half Deuteromere .

These together form a dimerous tooth.- Minute tuberculum impar or tubercle of carabelli

found occasionally on lingual aspect of deuteromere of the upper 1st molar.

Hypothesis of equivalence :Elements of mammalian set of teeth are all

morphologically alike. - The terms monocuspidate and multicuspidate possess only a descriptive anatomical value and do not indicate

any morphogenetic differences.- The tooth germ 'of every tooth possesses the

potentiality of developing all the cusps found in the most complicated tooth of set.

Dr. Begg noticed the teeth of Australian aboriginals who died before white man came to Australia. These

exhibited not only extensive occlusal and interproximal wear, but also exhibited an almost total lack of caries,

periodontal disease and tooth crowding.

He recognized along with several others that such an example of stone age man’s attritional

occlusion represented the true occlusion for man and not a pathological condition. Civilized man’s unworn dentition with all its related

problems is abnormal

Attrition causes continual changes in the shapes and size of teeth, mesial migration and continual

eruption in the presence of attritional results in their moving occluso mesially in the jaws.

Modern man and concieved normal

occlusion

Normal treatment goal using Begg

Technique

The Carabelli Trait

In 1842, Carabelli gave his name to a frequently occurring tubercle on the lingual aspect of mesio lingual cusp (protocone)

of the maxillary first permanent molar. Since that time, there has developed a vast literature relative to its classification, frequency,

comparative anatomy, evolutionary history, etiology, and morpho-genesis. The most recent comprehensive summary of the subject (Korenhof, I960) clearly points out the lack of agreement

among investigators in any aspect of the problem.

The wide range of hypothesis and conjecture concerning the Carabelli trait might properly be attributed to the paucity of research concerning its embryology. At least three theories

have been advanced explaining the occurrence of the Carabelli trait. One holds that the Carabelli cusp has its

origin in the cingulum, and numbers among its proponents Gregory (1922), Cope (1888), Osborn (1907), Adioff (1908),

and Korenhoff (1960).

A second school, led by Rose (1892) and Baufjeiff (1896),.claims that the Carabelli cusp arose as a seperate tooth germ. •The third group bases its rea soning upon the "Dimer" theory of Bolk (1914) in calling upon a "trito-mere" for the

origin of the cusp. -Other explanations are brought forth by in dividual authors such as Weidenreich (1937), who considered

the Carabelli cusp as an accidental variation" of the protocone,

It is indeed a most remarkable phenomenon in the history of biological researchthat so little is known

about a structure of which so much has been written.As Jorgensen rightfully points out that “our actual

knowledge of the evolutionary and racialsignificance of Carabelli's cusp is quite

disproportionate to the number of pages published about this structure.

Butler's Field TheoryReference is often made to specific teeth which seem to

show more variation than others. Much of this descriptive information on dental variation can be simplified if

Butler's Field Theory is understood. In 1939, Butler, an English paleontologist, proposed that the mammalian dentition can be divided into several developmental

fields. Varun Malhotra, Department of orthodontics , Bapuji Dental College and Hospital

Within each field, there is a "key" . tooth—one that is more stable developmentally—and on either side of this key tooth, the remaining teeth within the field become progressively less stable. The three fields include those for molars, premolars, incisors, mid

canines

The three fields include those for molars/ premolars, incisors, mid canines. Considering each quadrant separately the molar/premolar field would consist of the first molar as the key tooth. the second and third molars on the distal end

of the field, and the first and second premolars on the mesial end. The theory predicts that the third molar and first

premolar would be most variable in size and shape. Most clinicians would agree on the third molar but not on the

first premolar.

Actually the earliest mammals had four premolars and some of the higher primates. including man, have lost the first two, so that the premolars that we refer to as first and second should really be labeled third and fourth. The point is that as Butler's theory predicted, the premolars farthest

from the first molar were the first to be lost in an evolutionary sense and therefore can be considered the

least stable.

Adapting Butler's theory to the human dentition , Dalilberg suggested the following fields and gradients of

stability among teeth—the arrows indicate decreasing stability.

EVOLUTION OF SOCKET OR ATTACHMENTS OF TEETH :

There are 4 methods of tooth attachment in the animal world :1) Fibrous2) Hinged3) Anchylosis4) Gomphosis

Fibrous :- Seen in shark and rays- In this type of attachment the teeth are fixed by means of fibrous bands to the submucosa of the fibrous membrane which covers the jaws.- The teeth are developed on the lingual side of the jaw and move with the membrane up to the crest of the jaw where they come into use and over to the buccal side-where they are shed."- There is no calcified tissue intervening between the teeth and the jaws and therefore there is no homologous to the human alveolus.

Hinged teeth : Occurs in angler, hake, cod, and pike and many others The teeth allow ingress of the prey but prevent egress.

Example-ANGLERThis fish has 2 rows of teeth an outer ankylosed and inner

hinged row.- A hinged tooth is supplied posteriorly by fibrous elastic ligament, while its anterior free edge rests upon a buttress

of bone.- The teeth bent towards the throat, the hinge compresses and teeth return to their original positions upon the force

being removed.

Anchylosis attachment :- When a tooth is fixed to the jaw by calcified tissue it

is said to be anchyiosed.- There is no intervention of fibrous or uncalcified

tissue.Eel fish : The teeth of the Eel rest upon little cylinder or

cups of bone of attachment and is described as " Acrodont anchylosis".

-Little fibrous "annular ligament" surrounds the base of tooth and allows a slight movement.

Gomphosis (attachment in sockets)- Seen in man, mammalia, reptiles and in some fish eg

: saw fish, pristis.- In man, mammals and crocodile, a membrane

(alveolar dental membrane) exists between the tooth and the socket of bone in which the tooth is situated. To these persisting sockets the term " thecodont" has

applied.

Brash has shown that in case of pig when the teeth are lost, the alveolar processes becomes

transformed into basal portion of the jaw and that new sockets form for the successional teeth.

Gomphosis (attachment in sockets)- Seen in man, mammalia, reptiles and in some fish eg : saw fish,

pristis.- In man, mammals and crocodile, a membrane (alveolar dental membrane) exists between the tooth and the socket of bone in

which the tooth is situated. To these persisting sockets the term " Thecodont" has applied.

Brash has shown that in case of pig when the teeth are lost, the alveolar processes becomes transformed into basal portion of the

jaw and that new sockets form for the successional teeth..

Anthropology as a science has provided us with an insight into our past .The most important lessons that this science teaches us is that Evolution is an ever progressive process . Today we humans consider ourselves to be a privy to mother nature’s secrets of life ,the evidence can be seen with the aggressive

cloning ,customised D.N.A. planned offsprings, non discriminate use of natural resourses and creation of an utter chaos in the ecological balance of the planet by our species.

Thank you

ReferencesThe anthropology of modern human teeth – G.

Richard Scott. & TurnerScience and practice of occlusion – Charles

McNeillOrigins of life on earth – Gray’s Anatomy – pg 7.Orthodontics : Practice & Technique – J.A.

SalzmannContemporary Orthodontics – William R. Proffit.Plan of Face – Enlow – Ch. 5Illustrated encyclopeadia on evolution of life –

Time LifeAttritional Occlusion – Begg & KeslingDevelopment of Function & Evolution of teeth –

Mark F. Teaford & SmithThe morphogenesis of the TMJ – Moffit 1966

Stone age man’s occlusion – Am J Orth 1959; 40; 298 Dental variation among populations – D.C.N.A genetics –

1975 Evolution of dental occlusion form fish to man – W.K.

Gregory – Angle Orthodontics – Vol 11 No. 3 The Anatomic Museum – Marshal D.G. – AJO – 1992 Anthropology – World Book

1 anthropology

department of orthodontics

bapuji dental college

cultural evolution

humans thri e

e ol ing

birds thri e insects

albino fish

leading usvarun malhotra

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