Composite Bonding

Dental bonding is a technique that has been used in cosmetic dentistry for many years and can transform your smile in just a single visit. The process involves the skilful/artistic use of the correct amount and colour of "dental composite", which is a mouldable material with a paste-like consistency made from acrylic resins and a variety of fillers, depending on the type used. Bonding is used for a variety of cosmetic dental procedures, including:

Filling dental cavities - "white fillings" Replacing metal or amalgam fillings Repairing broken and chipped teeth Closing gaps between teeth (diastemas) Reshaping teeth Smile makeovers - composite veneers (although porcelain veneers are the better option for this)

Composite "white" fillings

Dental composite bonding is a popular choice for fillings because the material can match the shade, translucency and even the texture of your own natural teeth and provides a much better result than old amalgam/silver fillings, which can be unsightly when you smile. Cosmetic dentists often replace old metal fillings with tooth-coloured composite. There is much debate in dentistry as to the safety of mercury-containing amalgam fillings, and many dentists are of the opinion that metal fillings must be removed using a safe protocol, which involves isolating the teeth using a rubber dam material.

Can bonding be used for all cavities?

Bonding is not suitable if you have large cavities in your teeth, as the material does not have a strong structure over large areas. Bonding is ideal for small fillings that are not exposed to great forces. With recent advances indental technology, many dentists are turning to the use of CAD/CAM CEREC technology to produce ceramic fillings (inlays), which have the advantages of both strength and aesthetics and can be fitted in the same visit within an hour. Some practices may have their dental technicians fabricate a ceramic filling, which can take two to three weeks.

So what is the procedure of composite bonding?

If the procedure requires a local anaesthetic (not all bonding procedures do), your dentist will first numb the area by injecting a local anaesthetic into the gum area around the tooth. The tooth surface where the composite will be applied is thoroughly cleaned to remove any debris or tartar accumulation, as the composite needs a clean surface to bond to. Once the correct shade of composite has been selected by your dentist, the tooth is kept dry by surrounding it with cotton rolls or a latex sheet (rubber dam), and then shaped or roughened by the dentist using a special tool.

The surface of the tooth is then etched with a special phosphoric-acid-based gel, which provides a better surface for the composite to adhere to. The composite (bonding agent) is then applied to the etched tooth surface and exposed to a special light source (curing light), which activates the composite to harden and set. The bonding agent is often applied to the tooth in several thin layers (1mm-2 mm) until the desired shape, translucency and texture is achieved. The final step involves polishing and buffing the composite to give the desired shape and smooth finish.

What are the disadvantages of composite bonding?

The main drawbacks of bonding are that it doesn’t have the strength of other restorative materials such as ceramic or porcelain, and it has a greater tendency to stain than your surrounding natural teeth or porcelain.

Can any dentist carry out bonding?

Yes. However, you must note t hat bonding requires a high level of artistic skill and not all dentists are equally skilled. Some cosmetic dentists will have u ndertaken extensive postgraduate training in the field of dental bonding. Be sure to ask your dentist what experience he/she has in this area and if you can see photos of their previous work.

The term bonding is used in dentistry to describe permanently attaching dental materials to your teeth using dental adhesives and a high intensity curing light.

Whether you realize it or not, you've probably received a dental treatment involving either form of dental bonding: direct composite bonding or adhesive bonding of a restoration (crown, bridge, porcelain veneer, inlay/onlay) that was created in a laboratory or in-office.

Direct Composite Bonding / Composite veneer

Dentists use tooth-colored composites (white or natural-looking materials) that they have in their offices to fill cavities, repair chips or cracks, close gaps between your teeth and build up the worn-down edges of teeth. Dentists place the materials in or on the teeth where needed.

Because direct composite bonding involves the precise placement of restorative material by the dentist, the direct composite bonding procedure usually is completed in one dental visit. More complicated or extensive treatments may require additional visits. However, there is usually no need for temporaries or waiting days or weeks for laboratory restorations.

The same composite materials also may be directly applied and sculpted to the surfaces of teeth that show most prominently when you smile, for minimally invasive smile makeovers. While dentists call them direct composite veneers, many people just refer to them generically as “bonding.” Composite bonding usually is an ideal and less expensive solution for people with chips, gaps between the teeth, staining and discoloration, slight crookedness and misshapen teeth.

Although direct composite veneers typically require minimal preparations, no mold-taking and no temporaries, the artistic skill and precision of the dentist you choose will determine the exact manner in which your direct composite veneers are created. For example, some dentists use putty stents based on an impression of the patient's teeth and a model of their desired smile to guide them when placing the composite. This helps ensure a satisfactory result.

Adhesive Bonding

Adhesive bonding refers to attaching a restoration to a tooth using an etchant, a bonding agent, an adhesive and a high intensity curing light. This method is typically used for esthetic and metal-free crowns, porcelain veneers, bridges and inlays/onlays.

Understanding the Bonding Process

Whether your treatment plan calls for direct composite restorations or adhesively bonded restorations, dentists start the bonding process by using a rubber dam to isolate the teeth, to prevent interference from moisture. Depending on the extent of the treatment, anesthetic injections may be required.

Your dentist would then apply a gentle phosphoric acid solution to the surface of the natural tooth, which won't hurt. Similar to how roughing up a surface with sandpaper can help paint adhere to it better, acid etching of the tooth surface strengthens the bond of the composite and the adhesive. After 15 seconds the phosphoric acid is removed, and a liquid bonding agent is applied.

For a direct composite restoration:

• Your dentist then will place a putty-like composite resin in stages on the natural surface of the tooth, then shape and sculpt it.
• A high intensity curing light will be used to harden that layer of composite, and the previous step will be repeated, then cured, until the filling or direct composite veneer has reached its final shape.
• Your dentist also will create an appropriate finish to ensure that the bonded resin does not dislodge or cause tooth sensitivity.

For a restoration from a laboratory:

• Your dentist will place the appropriate adhesive into the restoration, seat the restoration on the tooth and light-cure it using a high intensity curing light for the appropriate amount of time.

It is not uncommon for a bonded tooth – particularly one that has been filled or on which a crown or inlay/onlay has been placed – to feel sensitive after treatment. This minor sensitivity is often short-lived, but if it persists, see your dentist.

Inlays and Onlays: The Indirect Filling Options

Inlays and onlays are dental restorations used by a select number of dentists. In certain cases, inlays and onlays are a conservative alternative to full coverage dental crowns. Also known as indirect fillings, inlays and onlays offer a well-fitting, stronger, longer lasting reparative solution to tooth decay or similar damage. These restorations are beneficial from both an esthetic and functional point of view.

Inlays and onlays can often be used in place of traditional dental fillings to treat tooth decay or similar structural damage. Whereas dental fillings are molded into place within the mouth during a dental visit, inlays and onlays are fabricated indirectly in a dental lab before being fitted and bonded to the damaged tooth by your dentist.

The restoration is dubbed an “inlay” when the material is bonded within the center of a tooth. Conversely, the restoration is dubbed an “onlay” when the extent of the damage requires inclusion of one or more cusps (points) of the tooth or full coverage of the biting surface.

Inlays and Onlays: The Benefits of the Conservative Approach

Superior Fit: Inlays and onlays offer a conservative preparation that preserves as much healthy tooth as possible. They are a great choice if you have minimal to moderate tooth decay that extends into a flossing area, offering an excellent alternative to full coverage crowns.

Tooth Color: Boasting esthetic longevity, inlays and onlays are not likely to discolor over time as tooth-colored resin fillings often do.

Tooth Structure Safeguard: Inlays and onlays preserve the maximum amount of healthy tooth structure while restoring decayed or damaged areas, helping to ensure functional longevity.

Easy Tooth Cleaning: Because the fit is tailored at all edges and the preparation minimal, your tooth can be easier to clean than it would be with full coverage restorative alternatives such as a dental crown. Composite fillings can shrink during the curing process, whereas prefabricated porcelain or gold inlays and onlays will not (ensuring a precise fit).

Tight Space Fulfillments: If you have a cavity between your teeth, consider an inlay rather than a direct composite filling. Inlays are better at sealing teeth to keep out bacteria; they are easy to clean, will not stain and offer exceptional longevity.

Strength and Stability: Inlays and onlays are extremely stable restorative solutions for the treatment of decay. The superior fit and durable material make inlays and onlays a stable choice that can actually strengthen a damaged tooth.

Weak Tooth Protector: An onlay can protect the weak areas of the tooth. The procedure does not require the complete reshaping of the tooth.

Inlays and Onlays: The Procedure

Typically, an inlay or onlay procedure is completed in two dental visits.

During your first visit, your dentist must prepare the damaged tooth. A molded impression of the tooth is then taken and sent to a dental laboratory, where an inlay or onlay is fabricated.

Inlays and onlays can be made from gold, porcelain or resin materials. The difference is in the appearance of the finished restoration. A fitted, provisional inlay or onlay (sometimes known as a temporary or “temp” for short) in the shape of the final restoration can be created during this visit to protect the tooth while the final restoration is being fabricated.

Your dentist might discuss with you the best type of inlay or onlay material to use. If esthetics is not a concern (for example, with back molars), gold is the best option. Porcelain inlays and onlays offer the best esthetics and are often used in the “smile line” areas. Resin materials may be the best option for people who grind their teeth and/or those with a misaligned bite (malocclusion).

During your second visit, the provisional temporary is removed and your inlay or onlay is placed.

Inlays and onlays are extremely stable restorations that seldom fail. Your dentist will check all margins to ensure a smooth fit with tight adjacent contacts. Your dentist will also check your bite to ensure that there are no occlusion-related problems affecting the margins of the restoration. Once fitted, the inlay or onlay is bonded onto the tooth and the margins are polished.

The Future of Inlays and Onlays

The materials used to fabricate inlays and onlays continue to evolve and become more natural and tooth-like in terms of structure, how they wear and their longevity. The use of inlays and onlays for restorative purposes is not likely to be replaced by another treatment any time soon due to the combination of excellent functional longevity and esthetic naturalness associated with inlays and onlays. In fact, maintaining tooth color over the course of your lifetime with an inlay or onlay may be further enhanced as the materials continue to improve, adding to the esthetic value of the restoration.

Selecting a Dentist for an Inlay or Onlay

There is no formal training offered for porcelain inlays and onlays in dental school and the number of continuing education courses is limited. As a result, there are a relatively small number of dentists who perform this type of inlay and onlay procedure.

Some dentists receive inlay and onlay training while working closely with their dental laboratory where the technicians are very willing to provide feedback on the best design for inlays and onlays. Some dentists have technology in their office that allows them to send images of your damaged tooth to a technician so that they can discuss optimal treatment options during your consultation. Dental technicians may also assist with treatment planning for upcoming cases by communicating in real-time with your dentist while you are in the chair.