Removable Prosthodontics at a Glance E-Book

James Field

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: At a Glance (Dentistry)
• Sprache: Englisch

Seitenzahl: 271

Veröffentlichungsjahr: 2020

Beschreibung

Removable Prosthodontics at a Glance provides a comprehensive and accessible guide to the practical elements of complete and partial denture provision. It serves as the perfect illustrated guide for learners, and a handy revision guide for subsequent undergraduate and postgraduate studies. Following the familiar, easy to use at a Glance format, each topic is presented as a double page spread with text accompanied by clear colour diagrams and clinical photographs to support conceptual understanding. Key concepts such as patient assessment, material handling, denture design, making impressions, and much more are explained and superbly illustrated enabling the reader to visualise the intended clinical endpoint. Removable Prosthodontics at a Glance is a valuable resource for students studying dentistry and clinical dental technology, and those preparing for further studies in Prosthodontics.

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The contents of this work are intended to further general scientific research, understanding, and discussion only and are not intended and should not be relied upon as recommending or promoting scientific method, diagnosis, or treatment by physicians for any particular patient. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of medicines, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each medicine, equipment, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.

Library of Congress Cataloging-in-Publication Data

Names: Field, James, 1979- author. | Storey, Claire, author.

Title: Removable prosthodontics at a glance / James Field, Claire Storey.

Description: Hoboken, NJ : Wiley-Blackwell, 2020. | Includes bibliographical references and index.

Identifiers: LCCN 2019056770 (print) | LCCN 2019056771 (ebook) | ISBN 9781119510741 (paperback) | ISBN 9781119510710 (adobe pdf) | ISBN 9781119510697 (epub)

Subjects: LCSH: Dentures. | Prosthodontics.

Classification: LCC RK656 .F495 2020 (print) | LCC RK656 (ebook) | DDC 617.6/92—dc23

LC record available at https://lccn.loc.gov/2019056770

LC ebook record available at https://lccn.loc.gov/2019056771

Cover Design: Wiley

Cover Image: Courtesy of James Field

CONTENTS

Cover

About the companion website

1 Introduction

Communication and expectations

The clinical process

2 The function of removable prostheses

Function

Restoring vs improving

Quality of life

Risks of removable prostheses

3 Stability and retention

Stability

Retention

Stability vs retention

The gag reflex

4 Patient assessment for complete dentures

The patient and the rationale for treatment

Prosthodontic history

Clinical examination

Ridge assessment

Assessment of existing prostheses

5 Edentulous ridge presentations

Upper edentulous ridges

Lower edentulous ridges

6 Patient assessment for partial dentures

The patient and the rationale for treatment

Prosthodontic history

Clinical examination

Ridge assessment

Partial denture classification

Assessment of existing prostheses

Radiographic assessment

7 Factors complicating success

Prognosis and justification

Risk factors

8 Accessibility and operator position

Posture and operating position

Move yourself, and the patient

Upper arches

Lower arches

Control of the prostheses and trays

Other considerations

9 Pre-prosthetic treatment

Extraoral assessment

Edentulous patients

Partially dentate patients

Periodontal disease and caries

Implants

10 Revisiting the anatomy

Upper arch

Lower arch

11 Making a primary impression – complete dentures

Choice of tray

Material

Lower arches

12 Making a primary impression – partial dentures

Choice of tray

Material

13 Special trays

Materials

Tray spacers and tissue stops

Handles

Material retention and support

Full seating

14 Compound and putty materials – handling and manipulation

Compound and greenstick

Putty

15 Recording an upper functional impression

Checking the special tray

Important functional anatomy

Posterior border

Partial dentures

16 Recording a lower functional impression

Checking the special tray

Important functional anatomy

Labial sulcus

Posterior and disto-lingual anatomy

Partial dentures

17 Managing fibrous ridges

Mucostatic

Mucocompressive

18 Denture bases

Types of denture base

Alternative denture base materials

19 Recording the maxillo-mandibular relationship

The denture bases

Natural tooth contacts in partially dentate patients

The registration material

A passive process

The process

Checking the registration

20 Prescribing the upper wax contour

Using the previous denture as a guide

Lip support

Incisal level and the alar–tragal plane

Buccal corridors

Other useful markers

Tongue space and assessing speech

21 Prescribing the lower wax contour

The tongue

Lip support

Incisal level and plane

Buccal relationship

Vertical dimensions, tongue space and speech

22 Tooth selection and arrangement

Biological markers

Tooth shapes

Tooth sizes

Tooth shade and characterisation

Other considerations

23 Occlusal dimensions and occlusal schemes

Conform or reorganise?

Occlusal schemes

Complete denture occlusal schemes

Facebows

24 Respecting the neutral zone

Diagnosis

Managing the neutral zone

The formal neutral zone impression

Effects of respecting the neutral zone

25 Assessing trial prostheses

What should be checked at try-in?

Managing occlusal discrepancies

26 Fitting and reviewing finished prostheses

Returning on casts

Checking the fitting surface

Checking occlusal contacts

Reviewing the prostheses

27 Copying features from existing prostheses

Tooth arrangements

Fitting surface

Full denture contour

Modifying prostheses prior to copying

How to create modified copy dentures

28 Classifying partial prostheses and material choices

Kennedy Classification

Applegate Classification

Potential difficulties with each class

Material choice

29 Designing partial prostheses

Preliminary registration

Other necessary information

A system of design

30 Saddles, rests and clasps

Saddles

Rests

Direct retention – clasps

Indirect retention

31 Connectors and bracing

Bracing

Major and minor connectors

32 Surveying and preparing guide planes

Should I survey for acrylic dentures?

Path of natural displacement

Path of insertion

Guide planes

Modifying the dentition

33 Designing frameworks – case examples

Example 1 – Upper Kennedy Class I, modification I

Example 2 – Lower Kennedy Class III, modification I

Example 3 – Upper Kennedy Class III, modification I

Example 4 – Upper Kennedy Class III, modification I

Example 5 – Upper Kennedy Class III, modification I

Example 6 – Lower Kennedy Class II

34 Precision attachments – the 
fixed–removable interface

Classifying precision attachments

Semi-precision rests

35 Dealing with frameworks and substructures

Try-in of the framework

Alloy teeth

Accounting for additions

Protecting small anterior saddles

Altering clasps

36 The altered cast technique and the 
RPI system

The altered cast technique

The RPI system

37 Swing-lock prostheses

What is a swing-lock prosthesis?

Indications

Contraindications

Assessing the periodontal condition

The latch assembly

Retentive elements

Connector design

38 Gingival veneers

Contraindications

Veneering materials

Indirect technique

Retention

Silicone vs acrylic

Shade taking

39 Immediate and training prostheses

Complete immediate dentures

Partial immediate dentures

Training prostheses

40 Occlusal splints

Splint types

Occlusal coverage

Records for construction

41 Implant-supported mandibular overdentures

Planning

Construction

Maintenance

42 Principles of restoring maxillary defects

Primary impressions

Major impressions

Framework designs

Obturator bungs

43 Tissue conditioners, liners 
and re-basing

Tissue conditioners

Soft liners

Degradation

Re-basing

44 Maintaining adequate oral hygiene

The impact of partial prostheses

Complicating factors

Cleaning partial and complete prostheses

Fixed prostheses

45 Troubleshooting loose or painful dentures

Loss of retention and displacement

Pain underneath denture bases

Other causes of pain

46 Gagging, other difficulties and 
making a referral

Managing the gagging patient

Tongue spread and lip activity

Speech problems

Referral process

47 Summary of procedural stages

Prescribing the placement of teeth and recording jaw relations

Partial denture design

Partial denture provision

Complete denture provision

Modified copy denture provision

Implant-supported mandibular overdenture provision

Appendices

Appendix 1: Complete denture assessment proforma

Appendix 2: Restorative assessment proforma

Appendix 3: Referral letters

Appendix 4: Partial denture design sheet

Recommended and supplementary reading

Index

End User License Agreement

Guide

Cover

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About the companion website

1Introduction

Removable prosthodontics is often described as a ‘black art’ – the Marmite of dentistry; practitioners tend to either love it or hate it. Fortunately, we love it – and with some simple guidance, hopefully you will too. Like most operative interventions, success depends on:

The skill of the dentist

The technical difficulty of the case

The patient's perceptions, ideas and expectations

Providing prostheses that are satisfactory to the patient is a challenge – and there are many reasons why patients can be dissatisfied with the finished result. Many relate to social aspects of patients’ lives – how they are able to interact with others, particularly when eating and speaking. Common reasons include:

Unacceptable aesthetics

Inability to chew food properly

Inability to enjoy the same foods as before

Problems with speech

Discomfort or persistent pain

Disagreements over time and cost

Despite the diversity of complaints, there is often a common thread running through them all – lack of information exchange and an inappropriate level of patient expectation. We would therefore argue that the most important skill when making satisfactory removable prostheses is that of communication.

Communication and expectations

Effective communication takes time. As clinicians we often start looking for mechanical reasons to explain why patients might be having difficulties with their existing prostheses – excessive movement, trauma or ulceration, poor retention, or design of coverage. On that basis, we often agree to make a new prosthesis. In reality, patient tolerance relates to very much more than just mechanics and physical function. It is crucial that the treatment you provide is driven by patient-perceived need. This means that patients need to understand and buy into the clinical rationale, including risks and benefits, of the proposed treatment. Similarly, we need to understand the patient's rationale for wanting a prosthesis. Given enough time, it is highly likely that these requirements can be met.

Often, the process of making removable prostheses begins with a primary impression. Try and break that habit, and implement these simple steps first:

Set aside at least 5 minutes to talk to your patient

Sit in front of your patient – do not stand in front of your patient with a stock tray in your hand!

Invite

your patient to explain why they would like you to make a denture – what are they hoping it will provide?

Crucially, your patient needs to feel that they can talk freely and comfortably about their tooth loss. This will not happen if they feel rushed, or feel that you are not actively listening to them.

This incredibly important part of the process is investigative. It should determine the choice of treatment that will follow. If the patient has an existing prosthesis, ensure that you ask what they think might change with a new one? What would they like to change?

It is at this early stage that you can begin to modify your patient's expectations if you feel that they are unrealistic. It is always better to begin this way, than back-tracking later and trying to reduce high expectations at the try-in or the fitting stages.

It is also a good opportunity to provide your honest thoughts on the likely outcome. We would caution against promising patients that their new prosthesis will be any better than the one that is being replaced, even if you can identify significant technical flaws. Instead, it is beneficial to ensure that you:

Reiterate why you think the patient would like a new prosthesis

Describe any technical features that you believe you can improve upon

Estimate how many visits, including retries and review appointments, you expect may be needed

Explain the fact that when the new prosthesis is fitted, even if it is technically better, it will still take a period of acclimatisation (up to 6 months, and longer in some cases) before the patient is able to function optimally

Generate an understanding that during this time, the patient will need to adapt

slowly

to their new prosthesis, even if it appears to function comfortably – and this is particularly important in relation to complete denture patients

The clinical process

Communication aside, the process of making removable prostheses is more manageable than it may seem at first. There are often simple approaches that can yield excellent results, without expensive materials or equipment. In the main, technical success is about attention to detail and knowing which materials work best in your hands.

The aim of this at-a-glance guide is to provide advice on how to achieve optimal outcomes at each clinical stage of the process. Our opinions are based on decades of combined experience teaching at undergraduate and postgraduate level, and routinely treating a wide range of cases. We have provided recommended reading for each chapter in case you wish to read more about the technical stages, or to understand better the theory and evidence base that underpins the fabrication of removable prostheses.

Educationally, we use the term ‘bricolage’ (tinkering) when we are teaching our students about new materials in the clinics. If it has been a while since you have used some of the materials in this book, then get hold of some of them, and have a play!

2The function of removable prostheses

Function

It is often assumed that the function of a prosthesis relates only to ‘mastication’ – but there are many other functions that removable prostheses can serve. As clinicians, we are often good at recognising technical reasons why dentures should be constructed – but often the social aspects from the patient's perspective are overlooked.

Be mindful that the prosthesis must serve a function as perceived by the patient. If we are constructing a prosthesis that has a clear clinical rationale, but the reasons are less obvious to the patient, then we must spend time explaining how we intend the prosthesis to help. Unless the patient understands and believes the rationale for their construction, they are unlikely to wear them regularly.

That said, it is remarkable what patients will tolerate in order to achieve a desired outcome. For example, a patient might wear their prostheses whilst they are out of the house in order to facilitate a more normal social life – even if it is painful – but it is likely that they will take them out once they enter the house again – especially if they live alone. This is probably not dissimilar to us kicking off a pair of shoes that have been rubbing – but made us look good. Many patients living alone also take their dentures out in order to eat – so do not always think that the primary function of your lovingly constructed dentures is to help your patient to chew!

It is important to remember that replacement of all of the patient's missing teeth is often unnecessary. That said, it is still critically important that denture bases are extended into the full denture-bearing area in order to maximise stability and retention – and this will be discussed further in the following chapters.

Removable prostheses are indicated primarily for the following clinical reasons (Figure 2.1):

Restoring masticatory function

Restoring appearance

Restoring speech

Restoring soft tissue bulk and providing soft tissue support

Acclimatisation during the transition to becoming edentulous

Removable prostheses are often indicated for the following technical reasons:

Restoring long edentulous saddles

Restoring multiple short edentulous saddles

Providing posterior stability and improving occlusal load distribution

Preventing undesirable tooth movements

Rehabilitating to an increased vertical dimension

Facilitating functional anterior guidance

In order to prescribe diastemata between prosthetic teeth

To avoid preparing abutment teeth for fixed prostheses

To avoid cantilevering from root-treated teeth

To aid planning and diagnosis, especially prior to implant placement

Finally, but by no means least, our patients may well request removable prostheses in order to:

Improve aesthetics

Restore social confidence

Improve their eating experience

Restoring vs improving

Notice that most of the clinical rationale is based around restoring or rehabilitating, whilst patient requests often centre around improving. This important subtlety can easily be lost when negotiating informed consent. Correcting technical deficiencies and restoring clinical function does not necessarily result in a patient-perceived improvement. Again, moderating patient expectations is critical at each stage of treatment.

Quality of life

One of the most profound moments as an undergraduate was when Professor Janice Ellis (Newcastle) asked us whether we would rather lose a leg, and have a prosthetic replacement, or lose all of our teeth and wear a denture? At the time this seemed like a ridiculous comparison to make – but actually as clinicians we do become desensitised to seeing edentulous patients or partially dentate patients. The bottom line is whether we really sympathise with our patients or not. By working on a daily basis with edentulous patients who are struggling to cope, it is relatively easy to sympathise with the condition – even if we are unable to fully empathise. However, if we converse with denture-wearers less frequently, then there is a chance that we forget about what Professor Ellis termed the ‘edentulous plight’. This reiterates why it is important that we take the time to listen to what our patients want, and that they feel comfortable enough to tell us.

Risks of removable prostheses

One of the most significantly overlooked aspects of denture provision is the potential negative impact on the hard and soft tissues. Primarily this relates more to the provision of partial prostheses – and patients should be made aware as part of the planning process (through informed consent) of the risks and benefits of receiving dentures. Do not assume that because your patient is already wearing dentures that there is no need to reiterate the potential risks.

Whilst the jury is probably out in terms of the impact on periodontal disease, there is clear evidence of an increased risk of plaque accumulation, gingivitis and root caries for patients wearing partial prostheses. Many well-conducted studies show that the key to minimising soft and hard tissue damage whilst wearing dentures is to maintain an optimal level of oral hygiene, and to attend regular review and maintenance appointments; this is very much a shared responsibility between clinician and patient. The patient must understand this, and the discussion should be well documented in the case notes.

3Stability and retention

Stability and retention are fundamental principles for the construction of removable prostheses – consequently, problems with retention and stability often underpin the patient's perception of the prostheses.

Stability

This can be defined as the resistance to horizontal displacement or rotation – in complete dentures, or around large saddles, this is often determined by the underlying anatomy and ridge form; this is primarily assessed in terms of the cross-sectional profile of the ridge, and how much support the ridge is able to provide before it distorts or displaces.

From time to time you will notice ridges that present with fibrous aspects, which have a tendency to displace on palpation and loading. You may notice these presentations being referred to as flabby ridges, but this expression is not so well received with patients! Fibrous elements can affect the whole aspect of the ridge, or just the crestal tissues. The impact this has on denture stability will be determined by which anatomical features are affected and is discussed further in Chapter 17.

When considering shorter or bounded saddles, elements of stability will be derived from the way in which the denture base contacts the hard tissues (either acrylic or cobalt chrome) and engages undercuts. This is largely determined by the ‘path of insertion’ (POI) and is discussed further in Chapter 32. To a degree, the stability of the prosthesis is therefore dependent on how effectively the neighbouring teeth can support lateral loading. This is known as ‘bracing’. If there is inadequate bony support for the abutment teeth then they will also move pathologically, and cause denture instability. This will cause further damage, possibly resulting in secondary occlusal trauma. These aspects will be discussed further, later in the book, in relation to partial denture planning.

Retention

This can be defined as the ability of the prosthesis to withstand removal in an axial direction – with complete dentures or areas over large saddles, this is often determined by the degree of coverage (employing cohesive and adhesive contact forces) and whether a border seal can be achieved. It is also important to consider the extensions of the prosthesis when assessing retention – whilst the prosthesis might be stable when fully seated, overextension may cause a lack of retention in function, as the functional sulcus shortens and displaces the denture base. When considering partial dentures and implant-supported overdentures (ISOD), retention becomes a much more active concept, through the use of direct clasps and retentive abutments. ISODs are considered further in Chapter 41.

Stability vs retention

I am often asked whether a denture can be stable yet unretentive – and vice versa. The simple answer is yes – to both. The technical challenge comes in ensuring that the prosthesis 
demonstrates both stability and retention. The key here is that the prosthesis covers the full denture bearing area – and accommodates functional movements within the periphery – the functional sulcus.

We will revisit the full anatomy of the maxillary and mandibular denture bearing areas (DBA) later – but some important anatomical and functional considerations for stability include:

The form of the edentulous ridge and palate

The degree of support offered by the ridges

The position of the polished surfaces in relation to the neutral zone (

Chapter 24

)

The degree to which the maxillary tuberosities are fully captured

The degree to which the disto-lingual anatomy is captured

Patients tend to learn how to improve the stability of dentures by improving muscle tone, tongue control and chewing habits. Whilst edentulous patients often have a habit of improving retention by holding dentures up with the posterior dorsum of the tongue, this appears to be a very patient-specific skill.

Important anatomical aspects for retention include:

Full coverage of the DBA

Developing an adequate border seal

Fully capture the maxillary tuberosities

Fully capture the lingual anatomy

Accounting for the insertion of buccinators into the retromolar pad

Ensuring that the denture is adequately extended, but not overextended, in function

Whilst the DBA and its extensions are very important, the position of the teeth is also critical, particularly in relation to the labio-lingual position of incisors on a lower complete denture. The concept of the neutral zone is very important and this will also be discussed later in Chapter 24. As well as the neutral zone, and impressions to record it, there are other prosthodontic techniques that can be employed to overcome challenges with fibrous ridges – such as:

The RPI design principle

The Altered Cast technique

Various mucostatic or mucocompressive impression techniques

These will be discussed further later in the book.

The gag reflex

This is discussed in more detail in Chapter 46 – however, it is worth mentioning at this early stage that the vast majority of patients presenting with a gag reflex are anticipating movement or loss of retention of their prosthesis. It may be that their current prosthesis is stable and retentive – however, most often I find that this is not the case. It is important to take the time to explain to patients that the best outcome is achieved if a stable and retentive denture is created first, which can then be used as a predictable tool for overcoming a gag reflex. Even in patients where counselling is required in order to overcome psychosocial triggers, a well-fitting prosthesis is necessarily the starting point.

4Patient assessment for complete dentures

Arguably one of the most important elements of your patient assessment, is about taking the time to understand what the patient wants and why. It is also about making a judgement about how likely you are to succeed with your endeavours – there are a number of risk factors that can alter your chances of success and these should be discussed and recorded before the active elements of treatment begin. The majority of these factors are outlined below, largely as bullet point questions, but please do visit the recommended reading section for details of other academic texts which explore some of these concepts in further detail. Please also see the sample Complete Denture Assessment Proforma in Appendix 1.

The patient and the rationale for treatment

Why does the patient want new or improved dentures?

Is there any difficulty chewing or speaking?

Do the dentures cause pain or nausea?

Do the dentures cause gagging, and if so, is it immediate?

Are the dentures of a satisfactory appearance?

Have any of these problems got worse recently?

Prosthodontic history

What type of denture is the patient currently wearing?

How old is the prosthesis and where was it/they made?

For how many years has the patient been edentulous?

How many prostheses has the patient received before?

Is the patient willing to attend for the necessary appointments, including review appointments?

Clinical examination

Before considering removable complete prostheses, it is important to carry out a full and comprehensive extra- and intraoral assessment. The following aspects can then be considered 
(Figure 4.1).

Intraoral access

 – Can the full denture-bearing anatomy be palpated easily, and can the existing prostheses be easily inserted and removed from the mouth?

Tongue

 – Does this occupy a normal space, or does it exhibit lateral spread? Is there a habit of using the tongue to retain the upper denture posteriorly?

Gag reflex

 – Can the full denture-bearing area be palpated without eliciting a gag reflex? If not, where are the trigger zones? These are most often the dorsum of the tongue, or the posterior palate.

Ulceration

 – Are there any existing signs of ulceration, and do they correspond to the extensions of a prosthesis?

Temporomandibular disorder (TMD)

 – Are there currently any signs of muscle pain or temporomandibular joint (TMJ) derangement?

Candidosis and angular cheilitis

 – How old are the prostheses and what is the patient's current hygiene regime? Does the patient seem to be over-closed? Is there a high carbohydrate intake throughout the day, nutritional deficiency or a dry mouth?

Dry mouth

 – Does the patient complain of a dry mouth? Is this medication-induced? You can grade a dry mouth using the Challacombe scale (see recommended reading).

Tori or significantly undercut ridges – 

If present will these interfere with the denture extensions or path of insertion?

Retained roots

 – Could these be retained as overdenture abutments?

Any suspicious lesions

, particularly for at-risk patients, that should be investigated or monitored alongside treatment?

Ridge assessment

Manual palpation is very important in order to assess the ridges adequately. This includes the ridge form (Figure 4.1) (well-formed, atrophic, rounded, flat, knife-edge, fibrous, undercut) and the proximity of the frenal attachments to the crest of the ridges.

Assessment of existing prostheses

The stability (resistance to horizontal or rotational displacement when fully seated) and retention (resistance to vertical displacement) of each prosthesis should be assessed in turn. It is easier to do this individually rather than having both prostheses in at the same time. The upper should be seated from in front of the patient, and whilst holding the molar units, should be rotated in a horizontal plane. It can then be displaced vertically, ensuring that the patient is not holding the denture in place with their tongue, to assess retention. The lower should also be seated from in front of the patient, ideally with the patient in a seated position. Stability can be assessed as above, but also in an antero-posterior direction by pinching the lower incisors between thumb and forefinger and moving the denture lingually and labially.

The denture extensions should then be considered – labial, buccal and posterior aspects – but also coverage of the tuberosities on the upper and disto-lingual extension on the lower. The anatomy of the denture-bearing area is considered in Chapter 10. 
It is important to assess the extensions systematically to look for under- or overextension. Direct vision is possible for the lower but it can be more challenging on the upper. Retracting the sulcus with your index finger parallel to the arch means that as you seat the denture, you can feel whether the sulcus is ‘pulled in’ towards the prosthesis. If this is the case, the denture is overextended in this area. It is also possible to take a wash impression in silicone or alginate to assess the denture extensions at this stage.

In terms of aesthetics – lip support, incisal plane and buccal space should be noted. These are considered further in Chapter 20.

Finally, in relation to the occlusion