Wheeler's Dental anatomy, physiology, and occlusion

485 Pages·1993·63.23 MB·English

by  Major M Ash

WHEELER'S
DENTAL ANATOMY,
PHYSIOLOGY AND
OCCLUSION
SEVENTH EDITION
MAJOR M. ASH Jr. DDS MS Dr.h.
MarwsL.
ward Profe55orofDenristry
andReswrchScientistEMI
School of Dentistry
University ofMichigan
,
W.B. SAUNDERS COMPANY
ADivisionof Harcourt Brace &Company
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W.B. SAUNDERS COMPANY
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Ash. M;Qor M.
Wh"~'lcr-sdcntalanalOmy.pbysiology and occlusion IMajot-M.
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Illcludes biblio,o;wphica! referenees IIndindex,
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I.l',-etb. 2-Occlusion (~nlisuvJ. I. Tille. 11-Tille: Dental
IIn:'h>tn}-.physiolOJY.andoeclusion.
II)NLM: I. Denial Occlusion. 2. TOOln-aIlJIlomr &-histolOS)'.
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ONLMiDLC '9497
WHEF.I ER'S DENTAL ANATOMY. ISBN 0-7216-4374-4
PHYSI( II,OGY AND OCCLUSiON
Copyl'it:btoCl 1993.I\IIS4. 1974.1%.S. 1958. 19:'iO,I940byW. B.Sa.unllt~Cumpany
Copyripu tt ediP.1968by RU$SJeIlC.Whecler
CopyriPI rme >edin1973byDouglas L.WheeIeT
All right, reserved. No part of this publication may be reproduced or Iran'mined inltny h>rm or b>'
anymca\l..elcctmnicormcchanicaLinciudinpphOiocopy.recordinll..1r'anyinful'mati"nst"ru8c
and relrkl'a] system. wilhout permission inwriting from the publisher.
PrinledinlbeUnitedSlatesofAmeril;a
la...tdir,it jsthe print number. , 8 7 6 , 4
Dedicated To
Fayola
Special Acknowledgments
It isapleasure to make special acknowledgment of the following individuals
who have suggested valuable information from their own special field of knowl-
edge. Discussions about the need for changes or addition ofmaterial to my manu-
script were most helpful and Iwishtospecify these individuals and their particular
fieldofinterest.
George M. Ash, B.S., D.D.S., M.S., A.B.O. (Orthodontics)
Jeffrey L. Ash, B.S.. D.D.S.. M.S. (Endodontics)
Carolyn M. Ash, B.S.. D.D.S., M.S. (Prosthodontics)
Sally Holden, R.D.H., R.D.A., M.S. (Dental Hygiene)
Hans Graf, Dr. Med. Dent.. P.D. (Periodontics)
Jose dos Santos, D.D.S., M.S.C.. P.D. (Restorative)
Stanley J. Nelson, D.D.S., M.S. (Occlusion)
,.
Preface
One of the challenges of a new edition is to make changes that reflect current
thinking in the field. and to delete material that is no longer pertinent to what is
being taught. Much of the guidance for change comes directly from teachers of
dental anatomy, some comes from the section on dental anatomy and occlusion of
the American Association of Dental Schools, and still more comes from an as-
sessment ofcurrent literature. .
Arecurring problem in teaching dental anatomy isthe inability of the student.
and often the clinician, to relate variations in the natural dentition to the restora-
tions for various patients, especially anterior teeth. Incisors look like inCisors. but
because of variations in size, color, wear, position, and shape. they may appear
quite different in various individuals. Such differences have continued to be recog-
nized in this edition.
One of the major goals of previous editions has been to provide details about
the morphology of human teeth that are relevant to the practice of dentistry. The
importance ofspecific anatomical features ofaparticular tooth to the diagnosis and
treatment of oral diseases has received very little attention in dental research and
hypotheses regarding such associations go untested and remain to be verified by
appropriate research. Past assumptions about the relationship between contours
and periodontal health continue to be reflected clinically in restored contours that
have very little relationship to function or aesthetics. Additional coverage of this
subject has been provided in this edition.
Relationships between developmental grooves. occlusal relations, pulp cham-
ber and root canal morphology. and the development of cracked teeth and pain
(cracked tooth syndrome) remain virtually unresearched. How then does the
clinician prevent cusp fracture or approach the restoration of a tooth (e.g.. the
distolingual cusp of the mandibular first molar) with silver (amalgam)? Part of the
answer must relate to the anatomy of developmental grooves, ocClusal relations.
facets of wear, and bruxism. Potential lines of fracture in developmental grooves
have been included in tl1'isedition.
Ofparticular interest inthis edition are the recent approaches to data concern-
ing standards of human tooth formation and dental age assessment. These kinds of
data have relevance to some clinical problems. as well as to other fields. Although
the dentition may be the single best indicator of chronological age in juveniles.
there are important gaps in available sources of tooth formation chronologies. For
a comprehensive review of methodologies by which critical choices among the
chronologies can be made, the reader isdirected to the references cited in Chapter
2, especially those of B. Holly Smith (199\) and Lunt and Law (1974).
vii
viii Preface
The eruption of atooth isacontinuous process that involves the movement of
a tooth in the bud stage to its emergence through the gingiva and finally into
occlusal contact. However, as a parameter of dental maturity, data on eruption
generally refers to the clinical appearance of the emergence of the tooth inthe oral
cavity. Although the term eruption is used erroneously to denote clinical emer-
gence, there appears to be no confusion as to what the term eruption means in
tables of the chronology of the human dentition. No attempt will be made in this
edition to change the term eruption to emergence in the tables and illustrations.
References that appear at the end of the chapters relate to specific citations in
the body of the text, as well as general support for the material presented. Some of
the older citations relating to descriptive studies have been replaced where appro-
priate literature was available.
Special thanks are given to the teachers of dental anatomy who have made
suggestions for correction or change in this edition, including Drs. E. M. Wilkins
and Stanley Nelson. Also acknowledged is the preparation of illustrations by
Professor William Brudon who, asalways, has turned rough sketches into works of
art. Thanks isgiven to Per Kje1dsen and Keary Campbell for photographic services
and Joanne Kazlauskas for her assistance in typing the revisions for the present
edition.
Major M. Ash, Jr.
Contents
Preface vii
1 Introduction 1
Nomenclature 1
2 Development and Eruption of the Teeth 24
Tooth Formation Standards 25
Chronologies of Human Dentition 25
The Primary Dentition 33
Permanent Dentition 36
Development ofthe Teeth 38
3 The Primary (Deciduous) Teeth 46
Life Cycle 46
Importance ofPrimary Teeth 46
Nomenclature 47
Major Contrasts between Primary and Permanent Teeth 48
Pulp Chambers and PulpCanals 50
ADetailed Description ofEach Primary Tooth, the Alignment of
Primary Teeth, and Occlusion 56
The Occlusion ofthe Primary Teeth 80
4 General Considerations in the Physiology of the
Permanent Dentition 84
Form and Function 84
Comparative Dental Anatomy 89
Tooth Form and Jaw Movements 93
AGeometric Concept ofCrown Outlines 97
Summary of Schematic Outlines 100
5 Physiologic Form of the Teeth and the Periodontium 102
Fundamental Curvatures 102
6 The Permanent Maxillary Incisors 128
Maxillary Central Incisor 128
Maxillary Lateral Incisor 140
.
ix
x Contents
7 The Permanent Mandibular Incisors 150
Mandibular Central Incisor 150
Mandibular Lateral Incisor 162
8 The Permanent Canines, Maxillary and Mandibular 170
MaxillaryCanine 171
MandibularCanine 182
9 The Permanent Maxillary Premolars 194
MaxillaryFirstPremolar 195
MaxillarySecondPremolar 209
10 The Permanent Mandibular Premolars 218
Mandibular First Premolar 218
Mandibular Second Premolar 231
11 The Permanent Maxillary Molars 2~1
Maxillary First Molar 2~2
Maxillary Second Molar 258
Maxillary Third Molar 266
12 The Permanent Mandibular Molars 274
Mandibular First Molar 274
Mandibular Second Molar 291
Mandibular Third Molar 299
13 The Pulp Cavities of the Permanent Teeth 308
ThePulpCavitiesoftheMaxillaryTeeth 312 .
ThePulpCavitiesoftheMandibularTeeth 337
14 Dento-Osseous Structures 359
The Maxillae 359
The Mandible 369
Arterial Supply to the Teeth 382
Nerve Supply 387
15 The Temporomandibular Joints, Muscles, and Teeth, and
their Functions 390
The Temporomandibular Articulation 390
Mandibular Positions 396
Mandibular Movements 399
Muscles 399
Mandibular Movements and Muscle Activity 408
Chewing 409
Swallowing 410
Contents xi
16 Occlusion 414
Concepts of Occlusion 414
An Outline of Items Suggested for the Study of Occlusion 4]5
Summary 467
Index 471