Dental Fillings

A Dentist will generally decide to place a filling in a tooth if there is a cavity present due to tooth decay or a tooth is fractured.

Alternatively, fillings can also be used to cover up enamel loss in order to protect a tooth from further wear, e.g. buccal abrasions, or improve the appearance, e.g. composite bonding. There are different types of filling materials which are used for different purposes:

Composite

Composite is the material that is used for white fillings. It is generally made up of ceramic particles that are combined with a resin base. It is often referred to as a synthetic material. Composite fillings are becoming more requested these days as more people are feeling more self-conscious of their teeth and want them to look as nice and natural as possible.

Advantages:

• Tooth-coloured and comes in many different shades.

• Bonds (glues) to the tooth for extra strength and less chance of leakage.

Disadvantages:

• Can be expensive.

• More time-consuming.

• Not ideal for posterior teeth as it is not as strong as amalgam.

To prepare for the placement of a composite filling, the following is needed:

• Instrument tray including a mirror, probe, excavator, wards carver or flat plastic, burnisher and tweezers.

• High and slow-speed handpieces with the necessary burs.

• Aspirator tip.

• 3 in 1 tip.

• Local anaesthetic (if necessary).

• Personal protective equipment (PPE) for you and the Dentist, (glasses, masks and gloves) and the patient (glasses and bib).

• Mouthwash and tissue for the patient.

• Millers forceps and articulating paper (to check the bite).

• Curing light and orange shield.

• Acid etch and bond.

• Composite material.

• Cavity lining material (optional).

• Rubber dam and accessories (forceps, hole punch, plastic frame and clamps).

• Matrix band/wedges or matrix strip.

After the Dental Nurse dresses herself and the patient in the correct PPE, the Dentist will use local anaesthetic (if necessary) to numb the area of the patient's mouth that is being treated. If the Dentist is using a rubber dam on the patient then this will be placed next. A rubber dam is a thin sheet of latex (or silicone if the patient is allergic to latex) that is placed over the patient's mouth. A hole is punched in the dam to expose the tooth that is being treated. Advantages of a rubber dam are that the tooth is isolated and protected against oral bacteria, blood and saliva and also that the tooth is kept dry, as when placing composite fillings, the tooth needs to be as dry as possible in order for the bonding process to be successful.

Once the patient is numb and comfortable, the Dentist will begin to shape the cavity and remove any caries (decay). Once the tooth is clean, the Dentist may place a calcium hydroxide lining material in the cavity. This tends to be necessary if a cavity is particularly deep. Depending on the surface of a tooth, the Dentist may need to use either a matrix band and wedge or matrix strip. A metal matrix band is used when more than one surface is involved in the filling and it creates a temporary wall for the composite to be supported on until it sets. The wedge positions the matrix band firmly. A matrix strip can be used when treating anterior teeth, it is placed in between the teeth in order to support composite mesially and distally before it is set. The Dentist will then etch and bond the tooth by applying the acid etch and leaving for a few seconds. The acid etch contains phosphoric acid and roughens the tooth surface leaving microscopic holes which allows the filling to bond tightly to the tooth. The Dentist then washes away the etch, dries the tooth and then applies the bond which allows the composite to stick to the tooth. After a few seconds, the Dentist will dry the tooth and then the Dental Nurse will use the curing light to set the bond using the orange shield for protection. The composite filling will then be placed into the cavity or bonded onto the tooth. The Dentist will shape the filling and then the Dental Nurse will use the curing light to set it for about 10-15 seconds. The Dentist may use a couple of layers of composite if the filling is particularly large.

Once the filling has set, the Dentist will check the occlusion (bite) by using articulating paper. This coloured paper is placed in between the filling and the occluding tooth and the patient is asked to bite together. If the filling is too big or a bit high, the paper will leave coloured marks on the spots of the tooth that need adjusting.

Once the occlusion has been corrected, the Dentist will polish the filling with either a fine bur, sof-lex (sandpaper) disc or a rubber cup.

Composite is also available in a liquid form- this is called flowable composite. Flowable composite can be used to fill in small spaces such as buccal abrasions and an occlusal surface in a screw-retained implant crown. It is set with the curing light just like regular composite.

Amalgam

Amalgam is the most traditional filling material used in dentistry and is made up of mixture of mercury and metal-the metal tends to be silver. Amalgam tends to be the most common filling material due to its low cost and strength/durability, however there are some health concerns with the fact that it contains mercury.

Advantages:

• Least expensive filling material

• Strong

• Durable

Disadvantages:

• Not aesthetically pleasing

• Contains mercury

• Does not bond to the tooth, it simply sits in the cavity

To prepare for the placement of an amalgam filling, the following is needed:

• Instrument tray including: a mirror, probe, excavator, wards carver or flat plastic, burnisher, packer and tweezers.

• High and slow-speed handpieces with the necessary burs.

• Aspirator tip.

• 3 in 1 tip.

• Local anaesthetic (if necessary).

• Personal protective equipment (PPE) for you and the Dentist, (glasses, masks and gloves) and the patient (glasses and bib)

• Mouthwash and tissue for the patient

• Amalgam capsule, pot and carrier.

• Cavity lining material (optional).

• Rubber dam and accessories (forceps, hole punch, plastic frame and clamps).

• Matrix band/wedges or matrix strip.

Once the patient is numb and comfortable, the Dentist will begin to clean away any tooth decay and prepare the cavity. The Dentist may place a calcium hydroxide lining material in the cavity. This tends to be necessary if a cavity is particularly deep. Depending on the surface of a tooth, the Dentist may need to use a matrix band and wedge. A metal matrix band is used when more than one surface is involved in the filling and it creates a temporary wall for the amalgam to be supported on until it sets. The wedge positions the matrix band firmly. The Dentist will then ask the Dental Nurse to prepare the amalgam. Once the amalgam has been mixed, the Dental Nurse will use the carrier to pick up the amalgam and pass it to the Dentist to start packing the cavity. If working four handed, whilst the Dentist is packing the cavity with a packer, the Dental Nurse will be picking up more amalgam with the carrier in preparation for the Dentist, then they will do a swap.

Once the filling has been placed, the Dentist will shape it correctly, usually using a wards carver or flat plastic. It is important to aspirate during this time to pick up any amalgam. The Dentist will check the occlusion and then lastly burnish the filling with a burnisher. This action is taken to improve the smoothness of the filling. Amalgam fillings take about 24 hours to fully set.

Glass Ionomer

Glass Ionomer fillings are fairly weak in comparison to composite and amalgam and for that reason are used mainly to fill deciduous teeth and surfaces of adult teeth that take little force or no force, such as the buccal surface. Glass ionomer can also be used as a temporary filling.

Advantages:

• Tooth-coloured.

• Releases fluoride over time which helps protect against tooth decay.

• There is often little or no preparation to the tooth in order to place the filling which is less invasive and also reduces the need to have local anaesthetic.

Disadvantages:

• Not very strong or durable

To prepare for the placement of a glass Ionomer filling, the following is needed:

• Instrument tray including: a mirror, probe, excavator, wards carver or flat plastic, burnisher and tweezers.

• High and slow-speed handpieces with the necessary burs.

• Aspirator tip.

• 3 in 1 tip.

• Local anaesthetic (if necessary).

• Personal protective equipment (PPE) for you and the Dentist, (glasses, masks and gloves) and the patient (glasses and bib).

• Mouthwash and tissue for the patient.

• Curing light and orange shield.

• Glass Ionomer powder and water or a ready-made mix.

• Mixing slab

Once the patient is numb and comfortable, the Dentist will begin to clean away any caries and prepare the cavity. If the Dentist is simply bonding the material on to the tooth then this won’t be necessary. When ready to place the filling, the Dentist will ask the Dental Nurse to mix the cement. Glass Ionomer often comes in “ready to mix” capsules, however it is still hand-mixed in some practices. On a glass mixing slab the powder and water should be mixed together until smooth. The Dentist will then take the cement and fill the tooth. If the Glass Ionomer used is light-curable, then the Dental Nurse would then set the filling for about 10-15 seconds. The capsules are generally light-curable however the traditional powder and water cement is not and takes about 24 hours to fully set.

The Dentist will then polish the filling with either a fine bur or a sof-lex (sandpaper) disc.