Download An Introduction to Orthodontics 3rd ed. - L. Mitchell - (Oxford, 2007) WW PDF

TitleAn Introduction to Orthodontics 3rd ed. - L. Mitchell - (Oxford, 2007) WW
TagsMedical
LanguageEnglish
File Size45.8 MB
Total Pages281
Document Text Contents
Page 1



Laura Mitchell

THIRD EDITION

online
resource

centre





Page 2





THIRD EDITION

















Laura Mitchell
MDS, BDS, FDSRCPS (GiasgJ, FDSRCS (Eng), FGDP (UK),
D. Orth RCS (Eng), M. Orth RCS (Eng)
Consultant Orthot:l:mtlst, St. Luke's Hosp.tal Bradford
Honorary Semor Climcol Lecturer. Leeds Dental Jnstitute. teeds

With contributions (r()m

Simon J. Littlewood
BDS. FOS(Orth) RCPS {Giasg), M Orth RCS (Edtn).
MOSt. FDSRCS {Eng)
Consultant OrthodontiSt, .)t Luke's Hospitaf. Bradford
Honorary Senior Clinical Lecturer. Leeds De.ntal JnstJtute, Leeds

Bridget Doubleday
PhD, M.Med.Sci., BDS. FDSRCPS tGiasg) M. Orth.
Consultant Odhodontlst and Honorary Semor Clinical Lecturer,

Glasgow Dental School. Glasgow

Zararna L. Nelson-Moon
MSc. PhD, BDS. FOS Onn RCS (Eng), M. Orth RCS (Eng),
Consultant Orthodontist and Honorary Senior Climcal Lecturer,

Leeds Dentallnstrcute. Leeds



OXFORD
UNIVERSITY l'RESS

..

Page 140









Chapter contents

12.1 Definitions

12.2 Aetiology of anterior open bite

12.2.1 Skeletal pattern

12.2.2 Soft tissue pattern

1 2.2.3 Habits

12.2.4 Localized failure of development

12.2.5 Mouth breathing

12.3 Management of anterior open bite

1 2. 3.1 Approaches to the management of anterior
open bite

12.3.2 Management of patients with increased vertical

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132

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132

133

133

133

134

134

skeletal proportions and reduced overbite 136

12.4 Posterior open bite 136

Principal sources and further reading 138

• •

Page 141

Anterior open bite and posterior open bite
�----�------·"----

1

1 2. 1 Defin itions

• Anterior open bite (AOB): there is no vertical overlap of the
incisors when the buccal segment teeth are in occlusion (Fig. 12.1) .

• Posterior open bite (POB): when the teeth are in occlusion there
is a space between the posterior teeth (Fig. 12.2).

• Incomplete overbite: the lower incisors do not occlude with the
opposing upper incisors or the palatal mucosa when the buccal
segment teeth are in occlusion (Fig. 12.3). The overbite may be
decreased or increased.

Fig. 12.1 Anterior open bite.

1 2.2 Aetiology of anterior open bite

In common with other types of malocclusion, both inherited and envir­
onmental factors are implicated in the aetiology of anterior open bite.
These factors include skeletal pattern. soft tissues. habits. and localized
failure of development In many cases the aetiology is multifactorial,
and in practice it can be difficult to determine the relative roles of these
influences as the presenting malocclusion is similar. However, a thorough
history and examination. perhaps with a period of observation. may
be helpful .

1 2.2.1 Skeletal pattern

Individuals with a tendency to vertical rather than horizontal facial
growth exhibit increased vertical skeletal proportions (see Chapter 4).
Where the lower face height is increased there will be an increased
inter-occlusal distance between the maxilla and mandible. Although
the labial segment teeth appear to be able to compensate for this to a
limited extent by further eruption, where the inter-occlusal distance
exceeds this compensatory ability an anterior open bite will result. If the
vertical, downwards, and backwards pattern of growth continues, the
anterior open bite will become more marked.



Fig. 12.2 Posterior open bite.

Fig. 12.3 Incomplete overbite.

In this group of patients the anterior open bite is usually symmetrical
and in the more severe cases may extend distally around the arch so
that only the posterior molars are in contact when the patient is in max­
imal interdigitation (Fig. 12.4). The vertical development of the labial
segments results in typically extended alveolar processes when viewed
on a lateral cephalometric radiograph (Fig. 12.5).

1 2.2.2 Soft tissue pattern

In order to be able to swallow it is necessary to create an anterior
oral seal. In younger children the lips are often incompetent and a
proportion will achieve an anterior seal by positioning their tongue
forward between the anterior teeth during swallowing. Ind ividuals with
increased vertical skeletal proportions have an increased likelihood of
incompetent lips and may continue to achieve an anterior oral seal
in this manner even when the soft tissues have matured. This type of
swallowing pattern is also seen in patients with an anterior open bite
due t� a digit-sucking habit (see Section 12.2.3). In these situations the
behaviour of the tongue is adaptive. An endogenous or primary tongue
thrust is rare, but it is difficult to distinguish it from an adaptive tongue

Page 280

••

Date of assessment:

Patient's name:

Address:

SKELETAL ASSESSMENT

Anteroposterior:

Vertical:

Transverse:

TMJ

SOFT TISSUE ASSESSMENT

Lip tonicity:

Smile aesthetics:

Tongue thrust: yes/no

INTRA-ORAL ASSESSMENT

Teeth present:

Oral hygiene:

Caries:

LOWER ARCH:

UPPER ARCH:

TEETH IN OCCLUSION:

Incisor classification:

Buccal segments Right side

Buccal segments Left side

QRTHODONTIC ASSESSMENT FORM

Orthodontist's name:

Date of birth:

Patients complaint:

Willingness for treatment:

Lip competence:

Periodontal condition:

Teeth of poor prognosis:

Overjet: mm Overbite:

Canines: Molar:

Canines: Molar:

Centrelines: _______ ______ _ Crossbites: _______ I ______ _
I

SUMMARY:

-

Page 281

From reviews of the previous edition

It is the sort of book that benefits from being read from start to finish by the undergraduaie
as it covers everything (and more) that they will need for their exams ... Anyone who is looking

for contemporary orthodontic information suitable for undergraduates and general dental

practitioners will find everything they need in this book

Journal of Orthodontics

Popular with thousands of students and clinicians, this book is the established introduction to the

study and practice of orthodontics. With the increased demand for, and expansion of, orthodontic

services, this third edition has been updated to provide a comprehensive orientation to cu rrent
thinking and practice for dental students, orthodontic therapists and busy cli nicians.

Coverage ranges from a completely revised and updated chapter on facial growth, through

assessment cephalometries and treatment planning for all types of malocclusion. Modern

appliance options are reflected, as well as the demand for adult orthodontics, and innovations in
interdiscipli nary orthodontics .

..

The ulti mate resource for those new to the study of orthodontics. the book also serves as a launch­
pad for those intending to specialise, and as an insight to orthodontic management of the developing

and established dentition for general dental practitioners, paediatric dentists and other specialists .

• Highly illustrated with over 400 colour photographs and worked case examples

• Provides practical resources on assessment and an in novative section on orthodontic

first aid

• Selected references are annotated to provide guidance towards further reading and the

developing evidence base

By the same author:

Oxford Handbook of Clinical Dentistry 4£ 2005
David A ... Mitchell and Laura Mitchell, with Paul Brunton

online resource centre
www.oxfordtextbooks.eo.uk/ordmitchell3e

Mitchell: An Introduction to Orthodontics 3e
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