Alfred Civilion Fones.

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CONTRIBUTORS.



FONES, ALFRED C, D.D.S.

HOPEWELL-SMITH, ARTHUR, Sc.D., L.R.C.P., M.R.C.S., L.D.S.

laRK, EDWARD C, D.D.S., Sc.D., LL.D.

MERRITT, ARTHUR H., D.D.S.

MINER, LEROY M. S., M.D., D.M.D.

OTTOLENGUI, RODRIGUES, M.D.S., D.D.S., LL.D.

STRANG, ROBERT H. W., M.D., D.D.S.

THOMA, KURT H., D.M.D.

TURNER, CHARLES R., M.D., D.D.S.



MOUTH HfGIENE



A TEXT-BOOK FOR DUiNTAL HYtilENlSTS



COMPILED AND EDITED BY

ALFKED C. FOXES, D.D.S.

BRIDGEPORT, CONNECTICUT



SECOND EDITION, THOROUGHLY REVISED



Mitb 218 miustrattons anO S platce




LEA & FEBIGER

PHILADELPHIA AND NEW YORK
192 1



.3



Copyright

LEA & FEBIGER

1921



PREFACE TO THE SECOND EDITION.



FnE years have passed since the pubHcation of the first edition of
Mouth Hygiene, and during that period a number of schools have been
organized for the education and training of the dental hygienist.
The experience of these schools has shown that several of the funda-
mental subjects, such as anatomy, physiology, bacteriology, hygiene
etc., require more extensive text than could be adequately covered in
any one book. It is, therefore, recommended that standard text-books
be utilized for such subjects.

The second edition of Mouth Hygiene endeavors to meet the need
of the dental hygienist for those subjects which pertain directly to
dentistry and which are essential to her education.

A. C. F.

Bridgeport, Conn., 1921.



sibitis



LIST OF CONTRIBUTOKS.



ALFRED C. TONES, D.D.S.,

Professor of Preventive Dentistry in Columbia University, New York City;
Director of the Division of Dental Hygiene in the Bridgeport, Conn.,
Department of Health.

ARTHUR HOPEWELL-SMITH, ScD., L.R.C.P., M.R.C.S., L.D.S.,

Professor of Dental Histology, Histopathology and Comparative Anatomy in
the University of Pennsylvania, Philadelphia.

EDWARD C. KIRK, D.D.S., Sc.D., LL.D.,
Editor of the Dental Cosmos.

ARTHUR H. MERRITT, D.D.S.,

Specialist in Periodontia, New York City.

LEROY M. S. MINER, M.D., D.M.D.,

Associate Professor of Dentology in the Boston University School of Medicine;
Assistant Professor of Oral Surgery in the Dental School of Harvard Uni-
versity, Boston, Mass.; Consulting Oral Surgeon to the Children's Hospital;
Oral Surgeon in the Forsyth Infirmary for Children; Chief of the Dental
Service in the Massachusetts General Hospital, Boston, Mass.

RODRIGUES OTTOLENGUI, M.D.S., D.D.S., LL.D.,

Editor of Dental Items of Interest.

ROBERT H. W. STRANG, M.D., D.D.S.,

Specialist in Orthodontia; Oral Surgeon to the Bridgeport Hospital, Bridgeport,
Conn.

KURT H. THOMA, D.M.D.,

Assistant Professor of Oral Anatomy and Pathology in the Harvard I'niversity
Dental School, Boston, Mass.

CHARLES R. TURNER, M.D., D.D.S.,

Dean of the School of Dentistry in University of Pennsylvania, Philadelphia.



CONTENTS.



CHAPTER I.



ANATOMY OF THE HEAD 17

By Robert H. W. Strang, M.D., D.D.8.

CHAPTER 11.

HISTOLOGY OF THE TEETH AND ASSOCIATED STRUCTURES . 58
By Robert H. W. Strang, M.D., D.D.S.

CHAPTER III.

THE TEETH AS A MASTICATING MACHINE ' 80

By Charles R. Turner, M.D., D.D.S.

CHAPTER IV.

MALOCCLUSION OF THE TEETH '..... 112

By Rodrigues Ottolengui, M.D.S., D.D.S., LL.D.

CHAPTER V.

INFLAMMATION 136

By Leroy M. S. Miner, M.D., D.M.D.

CHAPTER VI.

DEPOSITS AND ACCRETIONS UPON THE TEETH 149

By Edward C. Kirk, D.D.S., Sc.D., LL.D.

CHAPTER VII.

PYORRHEA ALVEOLARIS 166

By Arthur H. Merritt, D.D.S.

CHAPTER VIII.

DENTAL CARIES 173

By Edward C. Kirk, D.D.S., Sc.D., LL.D.



viii CONTENTS



CHAPTER IX.

ODONTALGIA AND NEURALGIA 191

By Arthur Hopewell-Smith, Sc.D., L.R.C.P., M.R.C.S., L.D.S.

CHAPTER X.

THE RELATION OF ORAL INFECTIONS TO GENERAL HEALTH . 203
By Kurt H. Thoma, D.M.D.

CHAPTER XI.

DENTAL PROPHYLAXIS 223

By Alfred C. Fones, D.D.S.

APPENDIX 299



MOUTH HYGIENE.

CHAPTER I.
ANATOMY OF THE HEAD.^

By ROBERT H. W. STRANG, M.D., D.D.S.
THE SKULL.

The twenty-two bones that enter into the formation of the osseous
framework of the head are united by immovable joints, the lower
jaw excepted, called sutures. These form a strong supporting and
protecting structure termed the skull (Fig. 1). This may be con-
veniently studied under four headings: (a) the cranium; (6) the base;
(c) the lateral aspect; (d) the anterior aspect or face.

The Cranium. — The cranium comprises that portion of the skull
which contains the brain. It is formed by the union of eight bones
which are named as follows: frontal, two parietal, occipital, two tem-
poral, sphenoid and ethmoid. In outline it is somewhat egg-shaped
and presents for study a superior surface, forming the vertex of the
skull, and an inferior surface.

The external surface of the vertex is convex and is covered in the
living subject by the tissues that form the scalp. This convexity of
surface is ideal for the resisting and warding off of blows. This surface
is traversed by three sutures arranged in the form of the letter "H."
The anterior cross suture which is situated well toward the top of the
skull is called the coronal; the one passing from this to the posterior
cross suture is the sagittal; the posterior transverse suture is the
lavibdoid.

The internal surface of the vertex is concave and is marked with
elevations and depressions for the accommodation of the irregidar
brain surface. Through the center, running anteroposteriorly, is a
groove in which lies the superior longitudinal sinus, a blood channel
performing the function of a vein and carrying part of the return
blood from the brain. To the margins of this groove are attached
some of the supporting membranes of the brain.

1 Bibliography: Gray's Anatomy; Piersol's Anatomy; Cryer, Internal Anatomy of
the Face; Deaver, Special Anatomy of Head and Neck; Swan, Manual of Anatomy;
Chapter on Anatomy of the Teeth, by C. R. Turner, in Johnson's Operative Dentistry.
2



18



AA'Al'OMY OF THE HEAD



There are also numerous smaller grooves in the bony surface which
radiate in various directions and in appearance resemble the branches
of a tree. In these run the ramifying branches of the middle meningeal
artery which supplies the cranial bones and dura mater with blood.

The inferior surface of the cranium corresponds to the cerebral
surface of the base of the skull (Fig. 2). It is divided by two trans-
verse ridges into three planes, arranged like terraces with the anterior
one on the highest level. These planes bear the name of fossce and
are called according to their position, anterior, middle and posterior.
Their surfaces are more or less irregularly concave, grooved to accom-
modate bloodvessels and perforated in many places to allow these
vessels and also nerves to pass in and out of the cranium.



ANTERIOR NASAL
SPINE



PROSTHIO



GNATHION




OBELION



Fig. 1. — Side view ol txpical skull. According to the present nomenckiture the hone
marked malar should be zygoma and that zygoma should be zygomatic arch. (Cryer.)



Description of the Fossae. — Anterior Fossa. — The points of interest
in this fossa arc (a) the prominent bony spine in the median line
called the crista (lalli (cock's crest); (b) near the front end of this
on either side, slit-like openings for tlie i)assage of the nasal nrnrs
into the nasal cavity; (c) the cribriform plate of the ethmoid bone
placed on a somewhat lower level than the rest of the floor of the
anterior fossa forming what is known as the olfactory groove. This
groove is divided antero])()steriorly by the crista galli, acconnnodatcs
the olfactory bull) of the brain and has its floor pierced with many



THE SKl'LL" 19

openings for the i)ass;ig{' of the olfactory nerves to tlu- nasal cavities;
{(i) the anterior and ])ostcrior ctlinioi(hil foramina, sitnatcd at the
outer edge of the cribriform phite, the former at about the middle
and the latter at the posterior end of the plate. The bone forming
the floor of the anterior fossa roofs over the orbital cavities.

Middle Fossa. In the middle fossa are seen (a) two o])enings that
communicate with the orbits. The smaller of these is the optic fora-
men, transmitting the optic nerve and ophthalmic artery to the eye;
the larger one is the sphenoidal fissure or anterior lacerated foramen,
for the passage of the third, fourth, ophthalmic division of the fifth
and the sixth cranial nerves, a sympathetic nerve, and also arteries
and veins to and from the orbits; {b) in the center of the fossa a bony
formation that resembles a saddle and for this reason is called the sella
turcica (Turkish saddle). In this bony structure is situated the pitui-
tary body, one of the so-called ductless glands, which secretes important
hormones that exert a marked influence on growth and development;
(c) on either side of this, four openings. The two anterior ones are
of particular interest because through them pass the divisions of the
fifth cranial nerve that go to the upper and lower teeth. The anterior
opening is the foramen rotundum and it transmits the superior maxillary
division of the fifth nerve. Behind this is the foramen ovale through
which passes the sensory and motor portions of the inferior maxillary
division of the same nerve. The smallest of the openings is the
foramen spinosum through which the middle meningeal artery enters
the skull. The largest of these four foramina is called the middle
lacerated foramen. This is closed in the living subject with cartilage.
On its posterior wall, however, is seen (d) the inner opening of the
carotid canal through which the internal carotid artery gains entrance
to the cranium.

The bone at the posterior aspect of the middle fossa acts as the
roof for the middle and internal divisions of the ear and is somewhat
irregular in conformation with their make-up.

Posterior Fossa. — The surface of this fossa is deeply concave and
accommodates the cerebellum. It is marked with (a) grooves for the
lateral sinuses carrying return blood from the brain. To the edges
of these grooves is attached the membrane supporting the cerebellum.
(6) The foramen magnum, centrally located, through which passes the
spinal cord; (/•) the anterior condyloid foramina for the passage of
the hypoglossal nerves to the tongue; (d) the jugular or posterior
lacerated foramina which affords a means of exit to the ninth, tenth
and eleventh cranial nerves as well as the lateral sinuses; (e) the
internal auditory meati for the passage of the auditory nerves ajid
arteries and the facial nerves.

The Base of the Skull. — The cerebral surface of the ba.se has just been
described under the heading of the Inferior Surface of the Cranium
(Fig. 2).



20



ANATOMY OF THE HEAD



Groove for super, sagittal sinus

Grooves for anter. meningeal vessels

Foramen ccecum

Crista galli

Slit for nasociliary nerve

Groove for nasociliary nerve

Anterior ethmoidal forainen

Orifices for olfactory nerves
Posterior ethmoidal foramen

Ethmoidal spine



Olfactory grooves

Optic foramen

Chiasmatic groove

Tuberculum sellae

Anterior clinoid process

Middle clinoid process

Posterior clinoid process

Groove for abducent nerve

Foramen lacerum.

Orifice of carotid canal

Hfpression for semilunar ganglion



Internal acoustic meatus

Slit for dura mater

Groove for superior petrosal sinus

Jugular foramen

Hypoglossal canal

Aquceductus vextibuli

Condyloid foramen



Mastoid foramen
Posterior meningeal grooves




Fig. 2.-Base of the skull. Inner or cerebral surface. (Gray.)



THE f^Kfl!.,



21



Incisors



Canine




Incisivf canal



TranxmitH left nannpalatine nerve
Traiixmilg dejice luti luj jialatine venselt
Tranxmits right naxupalatiiw. nerve



Lesser palatine foramina

Posterior nasal spine
Musculus uvulae
Pterygoid hamulus



Sphenoidal process of palatine
Pharyngeal canal



Tensor tympani

P/uiryngeal tubercle
Situation of auditory ttibe and
semtcanoil for Tensor tympani
Tensor veli palatini
Inferior tympanic canaliculus
— Aquardurtus cnclileae
Jugular foramen
Masbiid caiialiculux
Tympanomastoid /inmire



22 ANATOMY OF THE HEAD

The external or inferior surjace of the base (Fig. 3) (the mandible
removed) presents the following points for study : (a) In front is the
hard palate bordered by the teeth . Behind the incisor teeth is a depres-
sion in the palate known as the anterior palatine fossa. In the floor
of this fossa are four foramina for the passage of the naso-palatine
nerves and bloodvessels from the nose. On the hard palate opposite
the last molar teeth are the posterior palatine foramina transmitting
the descending palatine arteries and the anterior palatine nerves to the
hard palate. (6) Behind the hard palate are seen the posterior openings
of the nasal cavities on the outer sides of which are the two pterygoid
processes of the sphenoid bone, (c) External to these processes are
the zygomatic foss(je which contain three of the large muscles of mastica-
tion, the inferior maxillary division of the fifth nerve and the internal
maxillary artery. These fossBe communicate with the orbits by means
of the large sphejiomaxillary fissures . (d) Numerous foramina the most
important of which are: ovale, external opening of the carotid canal,
stylo-mastoid, posterior lacerated, condyloid and magnum, (e) Two
pairs of articulating surfaces, the one to receive the condyles of the
mandible and named the glenoid fossoB, the other to articulate with the
first vertebra. (/) The styloid and mastoid processes which form pro-
nounced landmarks and serve for the attachment of muscles.

The Lateral Aspect of the Skull (Fig. 1). — The following landmarks
present themselves for study, (a) The malar bone that forms the prom-
inence of the cheek. (6) The zygoma which lies very superficially and
aft'ords attachment to the masseter muscle, (c) The external auditory
meatus and (d) the styloid and mastoid processes. It is of interest
to note that practically all of the bone that enters into the formation
of the side of the skull above the zygoma is covered by the largest of
the muscles of mastication, i. e., the temporal.

The Anterior Aspect of the Skull or Face. — The anterior portion of
the skull is termed the face. The following fourteen bones enter into
its make-up: two nasal, two lachrymal, the vomer, two superior
maxillary, two malar, two inferior turbinates, two palate and the
mandible. Passing from above downward the following points of
interest are noted : (a) The supra-orbital foramina or notches through
which pass arteries and nerves bearing the same names. (6) The orbits,
in which well-protected cavities lie the eyes, (c) The nasal fosste.
(d) The infra-orbital foramina which transmit the infra-orbital arteries
and the end-branches of the superior maxillary nerves, (e) The
prominent malar bones. (/) The teeth of the upper and lower jaws
supported by their alveolar processes, (g) The mental foramina
through each of which an artery and nerve of the same name emerge.
(h) The mandible or lower jaw.

The Orbits. — These are irregular, conical cavities, with the base
toward the exterior and the apex inward. The outer edge of the
base is in the form of a strong bony ridge which ])rojects a little beyond
the eye and thus protects it from injury. Seven bones enter into the



TIIK SKULL' 23

formation of the walls of the orbits. On the superior aspect of tlie
outer wall near the base is a (le|)ressi()n for the hirliri/iiKil (/hnid. Each
orbit is in connnunication with various other cavities and fossu' by
means of the following openings: (a) The optic foramen and (6)
sphenoidal fissure open into the middle fossa of the cranial cavity; (c)
tlie si)henoniaxillary fissure gives entrance into the si)henoniaxillary
and zygomatic fossa'; (d) on the inner wall, the anterior and i)osterior
ethmoidal foramina, which transmit vessels of the same names and the
former also the nasal nerve, lead into the anterior fossa; and (e) the
nasal duct opens into the nose. The ])osterior ojjening of the infra-
orbital canal is seen on the floor of the orl)ital cavity.




First molar First molar

Fig. 4. — Vertical transverse section of typical skull. (Cryer.)

The Nasal Fossae (Fig. 4). — These are large, irregular shaped cavities
extending from the floor of the cranium to the roof of the mouth. They
are separated from each other by a thin partition made up of bones
and cartilage and called the nasal septum.

In front these fossiie communicate with the exterior by means of
two large openings called the anterior nares. In back they open into
the pharynx throngh the posterior nares or ehoan(F.

The lateral walls are \'ery irregular and are divided by shelf-like
bones named turbinates (scroll-like) into three or more sections called
meati. The turbinate bones are normally three in number and accord-
ing to their position receive the names of inferior, iniddle and snperior.

The floor of the nose is formed by the same bones that make up
the hard palate, i. e., the palatal processes of the superior maxillary



24 ANATOMY OF THE HEAD

and the horizontal processes of the palate bones. The superior surface
of these processes receives the name, "floor of the nose," while the
inferior surface is called the "roof of the mouth."

The nasal fossse are in communication by means of openings and
canals with the following cavities: (a) The cranium, (6) the orbits,
(c) the pharynx, (d) the mouth, {e) three sinuses, i. e., maxillary, frontal
and sphenoidal, and (/) three sets of air cells, i. e., anterior, middle
and posterior ethmoidal.

According to function the nasal foss^ are divided into two parts,
the olfactory and respiratory. The olfactory area is in the upper
portion and extends down to include the middle turbinate bones
on the one side and two-thirds of the septum on the other. The
respiratory portion takes in the remainder of the cavity.

The nose is lined with mucous membrane which in the olfactory
portion is non-ciliated but contains cells that are specialized to receive
the sensations productive of smell. That in the respiratory portion
is much thicker, contains large plexuses of veins and its cells are of
the ciliated variety. Many glands are found in the mucous membrane
of both portions of the nasal cavities. Their secretion is poured upon
the free surface of the membrane keeping this moist. The inspired
air is warmed as it passes over this membrane due to the heat imparted
from the great amount of blood found in the large venous plexuses.

The blood supply to the nasal cavity comes through the internal
maxillary, the ophthalmic and the facial arteries.

The nerve supply is of two kinds: (a) that of special sense through
the first cranial or olfactory nerve and (b) that of common sensation
through the fifth cranial or trifacial nerve.

The Bony Sinuses and Air Cells. — In all of the bones of the skull
that have any great bulk we find cavities. The largest of these cavities
are called sinuses while the smaller ones are called air cells. Their
function is to reduce the weight of the bone and in the region of the
mouth and nose to render the bone more resonant for the purpose of
speech. The most important of these sinuses and air cells are the
following :

Maxillary or Antra of Highmore.

Sphenoidal.

Frontal.

Anterior, Middle and Posterior Ethmoidal.

Mastoid.

The Maxillary Sinuses or Antra of Highmore (Fig. 4). — ^These are two
in number, situated within the bodies of the superior maxillary bones,
external to the nose and below the orbits. In shape they are some-
what pyramidal, with their bases directed toward the nose and the
apices at the prominence of the cheek. They oi)en into the middle
meati of the nose at points known as the infundibuhi. The antra are
often divided and partitioned by bony septa. They are lined with
mucous membrane which is directly continuous with that of the nose



THK SKULL,



25



and is covered witli ciliated epitlicliuiu. Tlie mucous inenihraiic also
contains jjlands. Often the roots of the molar and l)iscus])id teeth
form elevations on the Hoors of the sinuses and when diseased frecjuently
infect the mucous iiKMuhranc with most serious results.

The Sphenoidal Sinus (Fii,^ ")j- This air cavity may be a single one
but is usually partitioned into two distinct cells. It is situated within



Section turned up



Sella turcica



Auditory orifice



Posterior ethmoidal ccilf




Right frontal
sinus



Left frontal
sinus



Infundibulum

Anterior

ethmoidal cells
Hiatus

semilunaris
I'nciform

process

Middle meatus



Inferior concha
Probe passing

into lacrimal

duct
Inferior meatus



-" Hard palate



Alveolar
process



Fig. .5. — An anteroposterior section within the nasal ca\Tty, with the middle concha
and portion of the cell walls turned up. (Cryer.)

the body of the sphenoid bone at the posterior aspect of the roof of the
nose. It has an opening into the superior meatus and is also lined with
mucous membrane continuous with that of the nasal cavity. Often
the posterior ethmoidal air cells communicate with this sinus.

The Frontal Sinuses (Fig. 5). — These are two fairly large cavities
within the frontal bone. They are located unmediately above the
orbits and their position is marked approximately by the eyebrows.



26 ANATOMY OF THE HEAD

They are really a continuation of the anterior ethmoidal air cells of
their respective sides. They open into the middle meati of the nose.
Congestion of these sinuses is a usual sequence in a so-called " cold in
the head," and gives rise to the accompanying headache so frequently >
noted in this condition.

The Ethmoidal Air Cells (Fig. 5). — There are three sets of these found
within the lateral masses of the ethmoid bone and named according to
their position, anterior, middle and posterior. They are lined with
mucous membrane which is a continuation of that lining the nasal
passages into which each set of cells opens. These cells are often inter-
connected and frequently the posterior set communicates with the
sphenoidal sinus.

The orifices of the canals that lead from the nose to the anterior
ethmoidal cells are intimately associated with the openings into the
antra and into the frontal sinuses. Thus it is that the antrum, the
anterior ethmoidal cells and the frontal sinus of each side are made
intercommunicating and their mucous membrane linings practically
continuous with each other. These anatomical facts make it very
possible for an infection arising wuthin one cavity to travel to one or
both of the others. Cases are not uncommon in which an abscess on
the root of an upper molar or bicuspid tooth infects the mucous mem-
brane of the antrum and the discharge from this tissue passing into the
nose infects the lining membrane of the canal that leads to the anterior
ethmoidal air cells. The infection traveling up this canal will event-
ually involve these cells. The mucous membrane of the frontal sinus
may also become involved from the same source, either by an extension
from the nasal mucous membrane or directly from that of the anterior
ethmoidal cells. Such a pathological condition may be continued into
the middle and posterior ethmoidal cells and the sphenoidal sinus.

The mastoid air cells or antra are situated within the mastoid portion
of the temporal bones and will be mentioned under the description of
the ear.

THE EYES.

These are the organs of vision and consist of two globular bodies
situated within the orbits. They are freely movable by means of a
ball-and-socket joint formed between the eyeball and a tough, fibrous
membrane arranged in the form of a socket. This membrane receives
the name of the capsule of Tenon. Movement of the eyeball is per-
formed through the agency of six muscles that arise from the bony
wall of the orbit and are attached to the ball at various points.

The anterior portion of the eye is covered with a modified mucous
membrane which is reflected on to the lids and lines the inner side
of these. This membrane is called the conjunctiva and covers that
portion of the eye that is commonly called the " white."

The eyeball (Fig. ()) is made up of three coats within wliich are
three refracting media. The coats are named :



THE EYES



27



1 . Outer or fibrous.

2. Middle or vascular.
'A. luiuT or nervous.

The refrdcting tnpdia are:

1. Aqueous humor.

2. Oystalline lens.

3. Vitreous humor.



Sulcus circularut coiixta
Posterior chamber

Conjunctiva



Sulcus circularis comece
Cilirinj body



Rectus
lateralis




Zonular spaces



Hyaloid canal

Rectus
medial is



Sclera

Choroid



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