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Topic. Historical stages of Therapeutic Dentistry, its chapters. The value of scientific research of Ukrainian scientists. Dental instruments. Histological and clinical anatomy of the teeth. Dental charting. Signs of teeth.

Ternopil State Medical University named by I. Horbachevskyj

Department of Therapeutic Dentistry

Lecturer: Levkiv Mariana

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Dentistry, is the branch of medicine that is involved in the evaluation, diagnosis, prevention, and surgical or non-surgical treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent associated structures and their impact on the human body.

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Preventive dentistry and

Endodontology;

Periodontology;

Oral Pathology- (deals with oral

mucosa diseases)

Propaedeutic course;

• Therapeutic Dentistry includes such chapters:

 

BASIC INSTRUMENTS

• There are a few basic instruments that are universal to almost every procedure in dentistry.

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Hand instruments

Working end(s) of instruments•Are the functional parts of the instrument• Can have a variety of functions including: cutting, packing, carving, placing and condensing•Are adapted to the function of the particular instrument•May be bevelled (i.e. the working end is cut at an angle)• An instrument can be single-ended (one working end) or double-ended (two working ends)Shank of an instrument• The part between the working end and the handle• Can be straight or angled• The function of the instrument determines the angle and flexibility of the shankHandle of an instrument• Is the part of the instrument that the operator grasps• Design is related to the function of the instrument

Set of examination instrumentsMouth mirror

Functions••To provide indirect vision••To reflect light•• For retraction and protection of oral tissues•• For magnification (the number of the mirror represents size of mirror head)

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Sickle/contra-angled probe

Functions•• Detection of:• defective pits and fissures;• calculus;• deficient margins of restorations, crowns and bridges;• caries;•• Examination (pointed tip allows good tactile sensitivity)Varieties•• Can be single-ended or double-ended•• Many different styles available••Working ends may vary (straight, curved)

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Periodontal probe

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Function and features• Measure the depth of periodontal pockets•Tip is calibrated in millimetres•Blunt end reduces the possibility of tissue traumaVarieties• Single-ended or double-ended• Can be straight, curved or at right angles• Plastic types available

College tweezers

Functions•• Placing small objects in the mouth and retrieving small objects from the mouth•• Locking type ‘lock’ to prevent dropping materialsVarieties•• Locking and non-locking types••Working ends can be straight, curved, serrated or smooth

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INSTRUMENTS USED INBASIC RESTORATIVE

PROCEDURES

Spoon excavatorsFunctions and feature••A spoon-shaped working end for ‘spooning’ out dentinal caries from the cavity preparation•• Edges of working end are sharp•Any remaining caries will be removed with the conventional handpiece and a round bur

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Mixing spatulas

Function and feature•• Used to mix dental materials•• Anodised aluminium spatula will not stick to any composite materials or discolour materials

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Flat plastic instrument.

Also called: plastic instrumentFunctions••To deliver materials to the cavity preparation••To remove excess materialsVarieties••Various sizes and shapes available•• Can be single-ended or double-ended

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Round-ended plastic

Functions and feature••Used to create anatomical shapes in composite material during restorations••The ball-ended plastic instrument can also be used to pack and condense composite materials

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Rotary instruments

HANDPIECES AND BURS

•Dental handpieces and rotary attachments help to make dental treatment more comfortable for the patient and reduce the amount of time needed to complete procedures.

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Air turbine handpiece

Also called: fast handpiece, high speed handpiece, air rotor handpieceType•Contra-angledFunctions, precaution and features•• Removal of tooth tissue during restorations and preparation of teeth for fixed prosthetic appliances•• Polishing of restorations•• High speeds create heat and friction – handpiece must be run with water to cool the tooth to prevent pulpal damage•• High speed saves treatment time and reduces vibration

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Driven by•Turbine – may need to be lubricated – check manufacturer’s instructions• Compressed air rotates the turbine, which then rotates the burSpeedCheck manufacturer’s specifications (can run up to 500000rpm)GripAccepts friction grip attachmentsAttachmentDental unitVarieties• Different types of chucks available (e.g. those which need bur changing tool)•With or without light• Smaller heads for difficult access

Straight handpiece

Functions•• Used in surgical procedures to remove bone (cannot use air turbine as the water is not sterile)•• Used extra-orally at chairside or in the dental laboratory (e.g. for denture adjustments)Speed•can run up to 40 000rpmGrip•Accepts long shank attachmentsAttachment•Electric motor that fits into the base of the handpiece

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Slow Speed Handpieces

Type•Contra-angledFunctions•• Removal of caries•• Polishing••Procedures that require torque••Refine cavity preparations and adjust occlusionDriven by•GearsSpeed•The speed of the handpiece ranges from 0 to 40 000 rpmAttachment•Electric motor that fits into the base of the handpiece

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Burs

Head• This is the working end• Function depends on the size and shape of the head• Many different sizes and shapes, each used for a different function (cutting, polishing and finishing)Neck• The part that connects the head to the shank – usually narrows towards the headShank• The part that fits into the handpiece• Shapes and lengths vary, depending on function• Can sometimes be marked to identi-fy bur type (stripes or coloured bands)

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Some points to remember about rotary attachments and burs

• Most often called burs, but also available are wheels, discs, rubber points, rubber cups and stones• Each has a particular function (cutting, polishing, finishing or caries removal)•Are made from various materials (tungsten carbide, diamond and steel)• Can have flutes (the cutting edges)•The end of the shank determines which handpiece the attachment will fit into: Long straight shank – straight handpiece Latch grip – conventional type/slow speed handpiece Friction grip shank – air turbine handpiece/high speed handpiece Other various attachments such as snap or screw-type attachments

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Shape and function

• Shape determines function; the examples that follow relate to tungsten carbide burs:

• • Rose head/round – cutting and removing caries• • Pear – to shape the cavity preparation• • Fissure – to shape and prepare the cavity preparation

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Refers to the way the bur’s shank is ‘gripped’ into the handpiece •Composition••Refers to the head of the bur and what it is made from•• Generally:• Most latch grip burs are made of steel• Most fiction grip burs are made of tungsten carbide or diamond• Most long shank burs are made from steel if they are meant for surgical procedures and stainless steel if they are meant for laboratory purposes

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Grip and corresponding handpiece

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Anatomical and histological features of teeth

Tooth structure

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• Structure of enamel• Enamel is made up of millions of enamel prisms or rods,

which run from the amelo-dentinal junction to the enamel surface. Each prism is made up of a large number of enamel crystallites.

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Enamel

• Structure of dentine

• Dentine consists of many dentinal tubules that run parallel to each other, following a double curved course, and extend from the pulp to the amelo-dentinal junction. Each dentinal tubule contains an odontoblast process surrounded by intercellular ground substance composed of fine collagenous fibrils. The odontoblast cells are a layer of closely arranged cells on the pulpal surface of the dentine with their nuclei situated at the basal (pulpal) end of each cell.

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Dentine

Cementum

• Physical characteristics of cementum

• Cementum is a pale yellow, calcified tissue covering the root dentine. It is softer than dentine and can easily be worn away, resulting in exposure of the dentine. Its thickness varies according to location; it is thickest towards the apical third of the root and thinnest cervically.

• Chemical composition of cementum

• Cementum is 65% by weight inorganic (mainly hydroxy-apatite), 23% organic (mainly collagen) and 12% water.

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Dental pulp

• The dental pulp is surrounded by dentine and is contained in a rigid compartment.

• Functions of pulp• The dental pulp has the following functions:• ■ At late bell stage the cells at the periphery of the pulp

differentiate into odontoblasts forming dentine.• ■ It provides nutrients to the odontoblasts. (trophic function )• ■ It acts as a sensory organ especially when dentine is exposed.

The pulp rapidly responds to stimuli such as caries and attrition by laying down reparative or reactionary dentine. (reparative function)

• ■ It mobilises defence cells when bacteria enter it. (protective function)

• ■ Cells proliferating in the pulpal tissue create pressure; this is thought to play a part in tooth eruption.

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Periodontal ligament

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TEETH STRUCTURE

Primary teeth

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TEETH STRUCTURE

Permanent teeth

TOOTH FUNCTION

Types Function

1. Incisor Incisor is a tooth that has one root; function: to cut and cut off food.

2. Canine Canines are the teeth that have one root and has the function to rip the food.

3. Premolar teeth that had two/one roots; used to grind and chew food.

4. Molar Molar tooth is a tooth that has two/three roots; have a function for crushing and chewing food.

Morphological differences between primary and permanent teeth

• There are numerous differences between the primary and permanent dentition, many of which give rise to considerations in relation to operative treatment. Essentially, primary teeth have:

• ■ A shorter crown.

• ■ A lighter colour.

• ■ Narrower occlusal surfaces.

• ■ Thinner enamel and dentine.

• ■ Relatively larger pulps.

• ■ Curved roots

• (to accommodate the

• developing permanent

• successor).

Copyright © 2004 by Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED. 33

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Numbering Systems

• Universal/National System– Developed in 1968– Most commonly used in the United States

• Fédération Dentaire Internationale System– Canada and European countries use this– Easily adapted by computer and is widely

used in most countries

• Palmer System

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Universal numbering system

A system is used in the United States, called the universal system. This is a two-digit system but the teeth are numbered from 1 through to 32 in a clockwise direction starting with the upper right third molar:

Right 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 UpperLower 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 Left

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ISO/FDI numbering system

The mouth is divided into four quadrants and each quadrant is given a number, starting with the upper right quadrant and working in a clockwise direction. For example, the upper left quadrant is 2. The teeth are then allocated a number starting from the midline, so all central incisors are 1 and all third molars are 8. Therefore the lower right second premolar is 45.

Right 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28 UpperLower 48 47 46 45 44 43 42 41 31 32 33 34 35 36 37 38 Left

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Palmer Notation System

In this system, the dentition is divided into quadrants and the teeth in each quadrant are numbered 1 to 8 starting at the midline. Each quadrant is separated by a vertical line for right and left and by a horizontal line for upper and lower. Thus |6 is the upper left first molar in the permanent dentition. Right 8 7 6 5 4 3 2 1 | 1 2 3 4 5 6 7 8 Upper

Lower 8 7 6 5 4 3 2 1 | 1 2 3 4 5 6 7 8 Left

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Universal/National Numbering and Lettering System

Third molars

1

8 9

16

32

25 24

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Maxillary right

Maxillary left

Mandibular right

Mandibular left

Permanent teeth

Second molars

A

E F

J

KT

P O

Maxillary right

Maxillary left

Mandibular right

Mandibular left

Primary teeth

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Fédération Dentaire Internationale System for Numbering

1 1

Second molars

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1 1

5

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Maxillary right quadrant “5”

Maxillary left quadrant “6”

Mandibular right quadrant “8”

Mandibular left quadrant “7”

Primary teeth

Maxillary right quadrant “1”

Maxillary left quadrant “2”

Mandibular right quadrant “4”

Mandibular left quadrant “3”

Permanent teeth

1 1

1 1

8

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8

Third molars

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Palmer System for Numbering1 1

Maxillary left

quadrant

Mandibular left

quadrant

8

8

11

8

8

Permanent teeth

Mandibular right quadrant

Maxillary right quadrant

A A

E

E E

E

Primary teeth

Maxillary left

quadrant

Mandibular left

quadrant

Maxillary right quadrant

Mandibular right quadrant A A

Overview: Ergonomics and Health Implications for Dental Hygienists

• Increase awareness

• Decrease work-related pain and injuries• Heighten productivity• Improve musculoskeletal health• Increase comfort• Improve quality of life• Extend careers

What is Ergonomics?

• Ergonomics is the study of workers and their relationship with their occupational environment

• How you position yourself, your patient, how equipment is utilized, how the workplace is designed and how it impacts your health

• ERGONOMICS is a way to work smarter, more efficiently with less effort and discomfort to the human body

Ergonomics in the Dental Health Field

• Studies show work-related pain in the dental field is not decreasing

• Over half of all dental professionals continue to experience work-related pain

• Why? The physically challenging nature of the work with numerous risk factors 

Risk Factors

• Prolonged Static Postures

• Repetitive Movements

• Working in a confined space

• Challenges with positioning yourself or the patient

• Limitations with the tools and equipment used

©2008, Valachi from “Practice Dentistry Pain-Free”

Consequences of Poor Ergonomics

• Fatigue• Pain/Discomfort• Illness/Injury• Missed days at

work• Errors• Lower productivity• Patient

dissatisfaction

Poor Ergonomics: Signs and Symptoms

Physical Signs

• Decreased range of motion

• Deformity

• Decreased grip strength

• Loss of muscle function

Symptoms

• Pain

• Numbness

• Tingling

• Burning

• Cramping

• Stiffness

©2008, Valachi from “Practice Dentistry Pain-Free”

Poor Ergonomics = Musculoskeletal Disorders

The World Health Organization definition:

Musculoskeletal Disorder is “a disorder of the muscles, tendons, peripheral nerves or vascular system not directly resulting from an acute trauma or instantaneous event”

Two Most Common Causes for Musculoskeletal

Disorders in the Dental Health Profession

Cumulative Traumas

Prolonged Static Postures

©2008, Valachi from “Practice Dentistry Pain-Free”

Cumulative Trauma

• Repetitive Movements like Scaling and Polishing are Cumulative Traumas

• Vibrations transmitted by dental handpieces or mechanical scalers are Cumulative Traumas

• Cumulative Traumas add up

These microtraumas cause “wear and tear” on the muscles, tendons, and nerve tissue

Prolonged Static Postures

• Human body was designed for movement

• Dental hygiene procedures means practitioners must maintain static postures

• Hygienists hold postures that require more than 50% of the body’s muscles to contract to resist gravity

• Muscle overload leads to decreased blood flow and increased pressure on the muscles and joints

©2008, Valachi from “Practice Dentistry Pain-Free”