Lecture Introduction to occlusion

Trang 1 INTRODUCTION TO OCCLUSIONPart one Trang 2 Chapter 1: IntroductionMasticatory SystemDefinition of OcclusionChapter 2: Functional Anatomy of Masticatory SystemTemporomandibular Jo

INTRODUCTION TO OCCLUSION

Part one ANATOMY AND PHYSIOLOGY

OF THE MASTICATORY SYSTEM

Chapter 1: Introduction

Masticatory System Definition of Occlusion

Chapter 2: Functional Anatomy of Masticatory System

Temporomandibular Joint Skeletal Components of Masticatory System Masticatory or Jaw Muscles

Chapter 3: Considerations of Occlusion

Development of Deciduous Dentition Development of Permanent Dentition Considerations of Occlusion

Chapter 4: Kinesiology of Occlusion

Classification of Positions and Movements of the Mandible Border Movements and Positions of the Mandible Recorded

in the Sagittal Plane Border Movements and Positions of the Mandible Recorded

in the Horizontal Plane

Chapter 5: Functions and Parafunctions

Functions: Swallowing (Deglutition), Suckling, Chewing, Speaking Parafunctions: Bruxism, Clenching

After studying this lesson, the student should be able to:

1 present the concept of masticatory system and name the components

of the masticatory system.

2 define the subject of occlusion; differentiate from teeth

articulation or contact between the teeth and occlusion

§ INTRODUCTION TO OCCLUSION

Individual tooth is of great clinical significance A single tooth, by itself, however, can not perform the necessary masticatory and occlusal functions

the dentition, they become an essential component of the masticatory system

The masticatory system as a whole forms a functional unit, consisting of the

teeth and periodontium, the jaws, the temporomandibular joints, muscles

involved in moving the mandible (jaw muscles), the lip-cheek-tongue system,

the salivary system, the neuromuscular and vascular structures involved in the control, nutrition and maintenance of proper function

1.1 Masticatory System and its Components

1 MASTICATORY SYSTEM

The head houses and protects a number of anatomical structures which are

→ The masticatory system is but one of several functional units that use

anatomical structures in common with other systems

- Primitive or biological functions: swallowing (deglutition), suckling, chewing

- Social functions: Communication functions: including speaking, aesthetic ,

The functions of "tools" and "weapons" are still expressed, but do not play a

decisive role and no longer play the role of a meaningful function of life

1.2 GENERAL FUNCTIONS of the human masticatory system

The Two Group of Functions of Masticatory System:

2 DEFINITION OF OCCLUSION

“Occlusion” is one of the most commonly word used by the dental profession

The term “occlusion” is defined in the dictionary as

“the act of closure or state of being closed”

The Subject of Occlusion:

disturbances that occur as a result of, or are the cause of occlusal dysfunction

relationship between the teeth and other components of the masticatory system

as well as with other areas of the head and neck that directly or indirectly

related to function, parafunction, or dysfunction of the masticatory system

Occlusion is defined in many statements:

“The relationship between all the components of the masticatory system in normal function, dysfunction and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations

temporomandibular joint and muscle function, swallowing and mastication, psychophysiological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system” (Jablonski, 1982)

“Occlusion is the dynamic biological relationship of all components of the masticatory system to the contacting surfaces of the teeth in function and dysfunction, i.e the integrated function of jaw muscles, temporomandibular joints and teeth” (Klineberg, 1991)

Occlusion is a subject of the relationship of all components of the masticatory

system that related to the contacting occlusal surfaces of the teeth in function, parafunction and dysfunction These relationships are presented mainly on three main components: teeth and periodontal tissues, temporomandibular joints and jaw muscles, which are accumulated over time under certain psychophysiological status conditions

Tooth-Tooth contact Tooth-Tooth contact

Tooth-Tooth contact

DEFINITION OF OCCLUSION

which are accumulated over time under

certain psychophysiological status conditions

Teeth &

Periodontium

T -T

Time

Occlusion is the subject of the relationship of

all components of the masticatory system

that related to the contacting occlusal

surfaces of the teeth in function,

parafunction and dysfunction

These relationships are presented mainly

on three main components: teeth and

periodontal tissues, temporomandibular

joints and jaw muscles,

T – T = tooth–to-tooth contact

Note: Articulation : in dentistry, the static and dynamic contact

relationship between the occlusal surfaces of the teeth during function

In dentistry, the subject of Occlusion is in the unique position to provide a

common pool of information that can be used by all of the clinical disciplines

together

practice

The Central Role of Occlusion in Dental Education and Practice

Ardipithecus ramidus

(-6# -4.4 My)

Au anamensis (-4.12 My)

Au afarensis

“Lucy”(3.4 My)

Homo habilis (-2.5 - -1.5 My)

Homo erectus (-1.8 M – 400,000 Y )

Archaic Homo sapiens

(- 300,000 Y)

Homo s sapiens (100,000 Y)

H s neanderthalensis (-230,000 Y)

Đồ đá cũ - Sơ kỳ (Lower Paleolithic) Trung kỳ (Middle ~)

TEETH & SKULLS IN HUMAN EVOLUTION

Interglacial periods (Quaternary glaciation: -2,588,000y to present)

Au Africanus Paranthropus robustus

Prehistory (Tiền Sử) Protohistory (Sơ Sử)

History Lịch sử

3 EVOLUTIONAL CHARACTERISTICS OF THE HUMAN MASTICATORY SYSTEM

The main dento-facial changes in comparing between modern man and Homo

habilis, Homo erectus and Neanderthal man include:

A reduction in size of teeth and a reduction in

number of cusps in the permanent molars,

but little change in tooth form,

A greater reduction in size of alveolar processes with

a loss of facial prognathism and increasing tendency

for crowding of teeth

Homo erectus

H sapiens neanderthalensis

H sapiens sapiens

The development of the characteristic chin of

modern man

3 EVOLUTIONAL CHARACTERISTICS OF THE HUMAN MASTICATORY SYSTEM (cont’d)

Homo erectus

H Sapiens neanderthalensis

H Sapiens sapiens

The relative proportion of cranium to jaws has

changed in human due to both an increase in

cranium size and decrease in jaw size

These evidences of evolution and comparative

anatomy of the masticatory system can explain the

potential of abnormal function in human

The TMJ is a special structure of the masticatory

system in terms of anatomy and evolution:

the “temporal” is a part of the cranium that

increase in size the “mandible" is a part of the masticatory system,

→ TMJ is affected by two trends of evolution at the

same time