ART Manual - Chapter 3

of the mouth. The correct positioning of both the operator and patient is essential to achieve good quality care. This section describes the most appropriate working positions for both oral examination and treatment.

The operator's work posture and positions

The work posture and position of the operator should provide the best view of the inside of the patient's mouth. At the same time, both patient and operator should be comfortable.

The operator sits firmly on the stool, with straight back, thighs parallel to the floor and both feet flat on the floor. The head and neck should be still, the line between the eyes horizontal and the head bent slightly forward to look at the patient's mouth (Fig. 3.1a).

The height of the stool must then be adjusted so that the operator can see the patient's teeth clearly. The distance from the operator's eye to patient's tooth is usually between 30 and 35 cm. It is important that the stool is adjusted to the correct height for the eye focus of each operator.

The operator should be positioned behind the head of the patient. The exact position will depend on the area of the patient's mouth to be treated. If the patient's mouth is considered to be at the center of a clock face, see Fig.3.1c, the range of positions from which the operator can perform all tasks lies on an arc from 10 to 1 on the clock. The direct rear position i.e. at 12 o'clock and the right rear position i.e. at 10 o'clock are the most commonly used positions.

Assistance

Oral care is best provided by a team consisting of an operator and an assistant. However, assistants may not always be available. In such a situation the operator will have to provide oral care alone. When treating patients, particularly children using ART, it is a great advantage if another person can mix the glass-ionomer. This allows the operator to concentrate on the cavity and maintain effective saliva control. The operator should first demonstrate the use of instruments and the mixing procedure and train that person until he/she is able to mix the liquid and powder together correctly.

Seating Position of Assistant

The assistant works at the left side of a right-handed operator and does not change position. The assistant should sit as close to the patient support as possible, facing the patient's mouth. The assistant's head should be 10 - 15 cm higher than the operator, so that the assistant can also see the operating field and can pass the correct instruments when needed (Fig. 3.2a). The assistant needs a flat stable surface i.e. a table for holding instruments and materials.

Working Alone

The operator sits in the appropriate position behind the patient. A small table for holding the instruments and materials is either placed at the head end of the patient or on the right-hand side of the operator close to the patient's body (Fig. 3.2b).

Patient Position

As with any other oral treatment, ART requires correct patient and operator positions. A patient lying on the back on a flat surface will provide safe and secure body support and a comfortable and stable position for lengthy periods of time. A headrest made of firm foam or a rubber ring with a cover, both stabilizes the patient's head in the desired position and improves the comfort of the patient.

So the patient should be placed on a flat surface, e.g. a bamboo or wooden bed, an appropriate portable dental bed, or a table (Fig. 3.3). Assuming that a table is present in most communities, a very acceptable patient position is created by attaching a head support to the end of the table. A layer of foam plastic will provide more comfort (Fig. 3.4). The patient is now positioned so that the saliva collects in the back of the oral cavity. The operating field is now over the operator's lap at the height of the operator's chest (Fig. 3.2a).

Patient's Head Positions

The patient can assist the operator by tilting, turning the head and opening the mouth wide enough to provide access to the area of operation. These three movements are needed so that the operator has good access and vision during oral care.

1. Tilting the head

a. Backward tilt lifting the chin for access to upper teeth (Fig. 3.5a)

b. Forward tilt dropping the chin for access to lower teeth (Fig. 3.5b)

Figure 3.5

Backward and forward tilt of the head

a. Backward tilt

b. Forward tilt

2. Turning the head

a. Central position

b. Left turn

c. Right turn

Figure 3.6 Positions resulting from turning the patient's head a. Central position
b. Left turn c. Right turn

3. Mouth opening

a. Fully open.

b. Partly closed, to relax the cheek muscles for better access to buccal surfaces. The mirror is then used to hold the cheek away from the buccal surfaces.

Operating Positions

Operating positions are indicated by the location of the operator, the three positions of the patient's head and the type of vision - mirror or direct. The positions given are for right-handed operators and must be interchanged for left-handed operators.

a. Position for Upper Right Posterior Tooth Surfaces

The operator sits directly behind the patient's head. Mirror vision is used and the patient's head is tilted backwards with the mouth fully open (Fig. 3.7). Turning of the patient's head will depend on the surfaces to be treated on, i.e. for an occlusal surface - the central position, for a palatal surface of an upper right molar - turned slightly to the right, for a buccal surface of an upper right molar - turned slightly to the left.

Figure 3.7

Position for upper right posterior

- occlusal surfaces

operator

- direct rear

vision

- mirror

patient's head

- backward tilt

- central position

- mouth fully open

b. Position for Upper Anterior Tooth Surfaces

The operator sits directly behind the patient. Tilt the patient's head backward with the mouth open. The buccal surfaces are then viewed directly and the lingual surfaces are viewed through the mouth mirror.

c. Position for Upper Left Posterior Tooth Surfaces

For occlusal and buccal surfaces, the operator sits directly behind the patient's head. Tilt the patient's head backwards and turn it slightly to the right with the mouth fully open for occlusal and partly closed for buccal surfaces. A mirror is used to view the surfaces (Fig. 3.8).

For working on the palatal surface, the operator sits slightly to the right of the patient's head. Tilt the patient's head backwards and turn it slightly to the left with the mouth fully open for direct vision.

Figure 3.8

Position for upper left posterior

- occlusal surfaces

operator

- direct rear

vision

- mirror

patient's head

- backward tilt

- turned to the right

- mouth fully open

d. Position for Lower Left Posterior Tooth Surfaces

The operator sits to the right rear of the patient's head. The patient's head is placed in the central position and tilted slightly forwards. For occlusal and buccal surfaces, turn the head slightly to the right. The mouth should be fully open for occlusal views and partly closed for buccal surfaces to allow access for the mouth mirror. Direct vision may be used for most of the lower teeth (Fig. 3.9).

Figure 3.9

Position for lower left posterior

- occlusal surfaces

operator

- right rear

vision

- direct

patient's head

- forward tilt

- turned to the right

- mouth fully open

e. Position for Lower Anterior Tooth Surfaces

The operator sits directly behind the patient's head. Tilt the patient's head forwards in the central position. The mouth should be fully open and direct vision is used.

f. Position for Lower Right Posterior Tooth Surfaces

The operator sits to the right rear of the patient's head, which should be tilted forwards. For occlusal and lingual working surfaces, turn the head slightly to the right with the mouth fully open for direct vision. To view the buccal surfaces, turn the head slightly to the left with the mouth partly closed to allow access for the mouth mirror and hand instruments (Fig. 3.10)

Figure 3.10

Lower right posterior position

- occlusal and lingual surfaces

operator

- right rear

vision

- direct

patient's head

- forward tilt

- turned to the right

- mouth fully open

Operating Light

Good vision is essential for working in the oral cavity. The light source can be the sun (natural) or artificial. Artificial light is more reliable and constant than natural light and can also be focused on a particular spot. Therefore, in a field setting a portable light source is recommended e.g. a headlamp, glasses with a light source attached or a light attached to the mouth mirror. For all these three light sources, a rechargeable portable battery is the source of energy.

Figure 3.11

Glasses with a light source attached

3.2 Arrangements in the Mouth

A Dry Operating Area

A very important aspect for the success of ART is control of saliva around the tooth being treated. Cotton wool rolls are quite effective at absorbing saliva and can provide short-term protection from moisture/saliva. Rolls can be either bought or prepared from bulk cotton dressing pack. They must be changed when they have absorbed saliva. The location in the mouth and method of placement of cotton wool rolls is described below.

a. Upper Teeth

Retract the lip and cheek with the mouth mirror to make space between the cheek and teeth for the cotton wool roll (Fig. 3.12). Place the cotton wool roll in position with a slight rotating action from the tooth towards the gingiva. This will help prevent the cotton wool roll from coming out easily.

Always place cotton wool rolls in the sides of the mouth, as in the mid-line position, they will be easily dislodged (Fig. 3.12).

Figure 3.12

Correct positions of cotton wool rolls in the upper jaw

b. Lower Teeth

Ask the patient to stick the tongue out. Push the tongue aside with the mouth mirror. Place a cotton wool roll on each side of the floor of the mouth. Then ask the patient to retract the tongue back to its normal position. Also place a cotton wool roll in the buccal part of the upper jaw on the same side as the tooth to be treated.

Figure 3.13 illustrates the correct positions of cotton wool rolls in the lower jaw. Note that tension from the lip may dislodge the cotton wool roll if placed centrally.

Figure 3.13

Correct positions of cotton wool rolls in the lower jaw

3.3 Essential Instruments and Materials

Introduction

The correct instruments should be used for each treatment procedure. The success of any treatment depends on the operator knowing the functions of the various instruments and using them correctly. They must also be properly maintained in a good condition. This section describes the instruments used to perform the cavity preparation and restoration and how to keep them sharp.

Instruments for ART

a. MOUTH MIRROR. This instrument is used to reflect light onto the field of operation, to view the cavity indirectly, and to retract the cheek or tongue, as necessary.

Figure 3.14

Mouth mirror

b. EXPLORER. This instrument is used to identify where soft carious dentine is present (Fig. 3.15). Do not poke the point into very small carious lesions. This may destroy the tooth surface and the caries arrestment process. Also do probe into deep c

avities where you might damage or exposure the pulp.

Figure 3.15

Explorer

c. PAIR OF TWEEZERS. This instrument is used for carrying cotton wool rolls, cotton wool pellets, wedges and articulation paper from the tray to the mouth and back.

Figure 3.16

Pair of tweezers

d. SPOON EXCAVATOR. This instrument is used for removing soft carious dentine (Fig. 3.17). (For use see chapter 4, Cavity Preparation).

There are three sizes:

small. The diameter of the spoon is about 1 mm. An example is the Ash 153-154. This instrument is for use in small cavities and for cleaning the enamel / dentine junction. As the neck of the instrument is rather fragile, it can break if too much force is applied whilst excavating.

medium. The diameter of the spoon is about 1.5 mm. An example is the Ash 131-132. This instrument is mainly used for removal of soft caries from larger cavities. The rounded surface of the spoon can also be used to push mixed restorative material into small cavities.

large. The diameter is about 2 mm. An example is the Ash 127-128. This instrument can be used in large cavities and for removing of excess glass-ionomer material from the restoration.

The enlarged working blade of the excavator is illustrated in Fig 3.18.

Figure 3.17 Spoon excavator
Figure 3.18 Enlarged working blade of excavator

e. DENTAL HATCHET. This instrument is used for widening the entrance to the cavity, for slicing away thin unsupported and carious enamel left after carious dentine has been removed. The width of the blade of the instrument is approximately 1 mm. An example is the Ash 10-6-12 (Fig. 3.19). Figures 3.20 and 3.21 show enlarged views of the working blades of the dental hatchet.

Figure 3.19 Dental hatchet
Figure 3.20 Enlarged working blade of dental hatchet
Figure 3.21 Enlarged working blade of other side of dental hatchet

f. APPLIER/CARVER. This double-ended instrument has two functions. The blunt end is used for inserting the mixed glass-ionomer into the cleaned cavity and into pits and fissures. The sharp end is designed to remove excess restorative material and to shape the glass-ionomer. An example is the Ash 6 Special (Fig.3.22).

Figure 3.22

Applier / Carver instrument

g. MIXING-PAD and SPATULA. These are necessary for mixing glass-ionomer (Fig. 3.23). There are two types of mixing pads; glass-slab and disposable paper pad. The spatula may be made of metal or plastic. The spatula used must bend so that it is easy to mix the powder and liquid rapidly and correctly. Sometimes glass-ionomer is supplied together with a plastic spatula and the paper pad.

Figure 3.23

Glass-slab and spatula

Materials for ART

Besides the adhesive restorative material glass-ionomer, there are a few other essential materials necessary to perform ART.

a. COTTON WOOL ROLLS. These are used to absorb saliva so that the tooth to be treated is kept dry.

Figure 3.24

Cotton wool rolls

b. COTTON WOOL PELLETS. These are used for cleaning cavities. They are available in various sizes. The smallest, size 4, should be used for small cavities. Size 2 can be used for larger cavities.

Figure 3.25

Cotton wool pellets

c. PETROLEUM JELLY. This material is used to keep moisture away from the glass-ionomer restoration and to prevent the examination glove from sticking to the glass-ionomer as it sets hard.

d. PLASTIC STRIP. This material is used for contouring the proximal surface of multiple-surface restorations (Fig. 3.26).

Figure 3.26

Plastic strip

e. WEDGES. These are used to hold the plastic strip close to the shape of the proximal surface of a tooth so that restorative material is not forced between the gums and teeth (Fig. 3.27). These wedges should be shaped from soft wood.

Figure 3.27

Wedges

Sharpening Dental Instruments

Hand instruments used for cutting hard tooth tissues, the excavator, dental hatchet and carver, must be sharp to be effective.

A blunt instrument is a definite hazard, as it requires excessive force to cut enamel and dentine. The sharpness of the cutting edge can be tested effectively on the thumbnail. If the cutting edge digs in during an attempt to slide the instrument over the thumbnail, the instrument is sharp. If it slides, the instrument is blunt. Only light pressure is exerted in testing for sharpness (Fig. 3.28).

Figure 3.28

Testing the sharpness of an instrument

Sharpening the Dental Hatchet and Carver

A special flat stone, for example an 'Arkansas' stone, is used for sharpening the hatchet, carver and spoon excavator. The procedure to follow is described below step-by-step.

1. Place the flat sharpening stone on a table.

2. Put a drop of oil on the stone.

3. Hold the stone firmly with one hand and rest the middle finger of the other hand on the stone as a guide.

4. Position the cutting edge of the hatchet or carver in the oil parallel to the surface of the stone (Fig 3.29).

5. Slide the instrument back and forth over the stone several times for maximum sharpness. Take care that the surface to be

sharpened stays parallel to the stone surface.

Instruments should be sterilized after they have been sharpened.

Figure 3.29 Correct and incorrect position of dental hatchet for sharpening Instrument must be held parallel to the flat surface of the sharpening stone (Fig. 3.29a)
Figure 3.30 Positioning of fingers when sharpening hatchet and carver

Sharpening Spoon Excavator

As for the dental hatchet and carver, a flat 'Arkansas' stone is used for sharpening. The procedure to follow is described below step-by-step.

1. Place the flat sharpening stone on the table.

2. Put a drop of oil on the stone.

3. Hold the stone firmly with one hand.

4. Place the round surface of the excavator in the oil and make small strokes from the center of the round surface to the edge of

the spoon. Do this in all directions so that the entire cutting edge is sharpened.(Fig. 3.31)

Figure 3.31

Sharpening of spoon excavator

3.4 Hygiene and Control of Cross Infection

If available, always wear gloves. Cleaning and disinfection of the working place and sterilization of instruments is essential to prevent infection passing from operator to patients and vice versa or between patients via the operator. Cleaning and disinfection of surfaces in the working place can be done by using cotton gauzes impregnated with methylspirit (alcohol). In a clinic, instruments can be sterilized in an autoclave or a pressure cooker. If not in the clinic, a pressure cooker or a pan with a lid to boil the instruments can be used.

To avoid the risk of infection with diseases such as the human immunodeficiency virus (HIV) and hepatitis B virus (HBV), all instruments must be sterilized before being used for each patient.

Cleaning and sterilizing instructions.

1. Place all instruments in water immediately after use.

2. Remove all debris from the instruments by scrubbing with brush in soapy water.

If an autoclave is available, follow the manufacturer's instructions carefully.

If a pressure cooker is available, the instructions presented below are useful.

3.In a field situation:

- Prepare fire using the fuel available - wood, gas, charcoal, solar energy.

- Put the clean instruments in a pressure cooker and add clean water to a depth of 2-3 cm from the bottom.

(Read instructions supplied with the pressure cooker).

- Place the pressure cooker on the stove and bring to boil. When the steam comes out from the vent, put the weight in place.

If available, set a timer for 15 minutes.

- Continue heating the pressure cooker on low heat for a minimum of 15 minutes. Ensure that steam continues to be released

from the pressure cooker during this time. If this stops, there may be no water left in the pressure cooker anymore.

If this happens remove the pressure cooker from the heat, add water and repeat the cycle.

(Read the instructions supplied with the pressure cooker).

Take care when opening the pressure cooker.

Release the pressure first.

- Remove the pressure cooker from stove after 15 minutes, and leave it to cool.

- Take instruments out of pressure cooker with instrument forceps and dry them with a clean towel.

Store them in a covered, preferably, metal box

If a pressure cooker is not available, instruments can be sterilized in a pan. Use a pan with a lid and boil them in water for a minimum of 30 minutes. Remove the instruments with instrument forceps immediately and dry them with a clean towel. Store the instruments in a covered, preferably metal box

3.5 Treatment Material

Introduction

The material used for restoring cavities and sealing pits and fissures is glass-ionomer. This material must be used correctly for achieving good results. This section describes the composition, characteristics and mixing procedures of glass-ionomer.

Glass-Ionomer as a Restorative Material

Composition

The material is supplied as a powder and liquid that must be mixed together. The powder is a glass containing silicon-oxide, aluminum-oxide and calcium fluoride. The liquid is either polyacrylic acid or de-mineralized water. If de-mineralized water is the liquid component, polyacrylic acid is incorporated into the powder in a dry form. (de-mineralized or de-ionized water is used to top up batteries. It can be bought at garages)

Clinical Characteristics

- Glass-ionomer bonds chemically to enamel and dentine and provides a good cavity seal.

- One of the most significant characteristics of glass-ionomer is the continued slow release of fluoride from the material

after it has set. This helps prevent dental caries developing around the restoration.

- Glass-ionomer is not harmful to the pulp and gingiva. During setting, the material may cause the pulp to feel tender.

After 24 hours, when completely set, adverse reactions do not occur anymore.

- Compared to established dental restorative materials, glass-ionomers have higher surface wear and lower strength.

However, manufacturers are in the process of producing glass-ionomers of improved quality.

Therefore the best type of glass-ionomers available should be chosen.

Mixing

It is essential to closely follow the handling instructions of the manufacturer particularly with respect to powder and liquid ratios. Place a spoonful of powder on the glass slab or mixing pad. Use the spatula to divide the powder into two equal portions, then dispense a drop of liquid next to the powder (Fig. 3.32). Hold the liquid bottle horizontal for a moment to allow air to escape from the tip. Move it to a vertical position and allow one drop of liquid to fall onto the slab.

Apply a little pressure if necessary, but do not squeeze the liquid out.

Figure 3.32

Situation before mixing starts

First spread the liquid with the spatula over a surface of about 1.5 cm2. Start mixing by adding one half of the powder into the liquid using the spatula. Roll the powder into the liquid, gently wetting the particles without spreading them around the slab. As soon as all powder particles are wetted, the second portion is folded into the mix. Now mix firmly while keeping the mass together. The mixing should be completed within 20-30 seconds, depending on the brand of glass-ionomer used.

The final mixture should look smooth like chewing gum.

Figure 3.33

Mixing glass-ionomer

Restoring the Cavity

Insertion of the mixture into the prepared cavity and over the remaining fissures must begin immediately. Use the applier/carver to place small amounts of the mixture into the cavity. This technique will avoid air being trapped between the floor of the cavity and the glass-ionomer (voids). The entire application procedure must be completed within 30-40 seconds.

Precautions to Remember

Dispense both powder and liquid onto the slab only when you have the cavity properly dried and protected from saliva.

Replace the lid of powder and liquid bottle carefully back into position immediately after use. This prevents uptake of moisture from the air or evaporation of the water component from the liquid.

Wipe the nozzle of the liquid bottle with a damp gauze if liquid remains on the outside.

If more than 30 seconds are used for mixing and the mixture looks dry, do not use it, because there will be poor adhesion to the tooth structure. Throw it away! Scrape the slab and spatula clean and start mixing again with new powder and liquid.

Remove all glass-ionomer from the dental instruments immediately after use before the material has hardened, or put the instruments in water for easy cleaning later.

Each type of glass-ionomer may have its own specific needs. Therefore, follow the instructions of the manufacturers carefully.