A dental inlay is made up of a solid customised filling material that covers the grooves of a tooth but does not extend over the cusps of the tooth. Inlays can be made of gold,composite resin, amalgam or porcelain. The material is opted based on several factors like the size and depth of the cavity, tooth involved etc. In the past,Inlays made of gold were used as fillings to replace the loss of a small quantity of tooth structure due to caries or fracture. Today, inlays made of an enamel matching material such as ceramic/porcelain or special dental composite are preferred options to fill a small cavity. Tooth-colored inlays can be used to treat defective or ugly looking fillings. Inlays are bonded to the tooth and this may actually improve the strength of the tooth and maintain a tight seal.
Onlays are fitted inside the tooth like the inlays, but unlike them, extend onto the chewing surface of a posterior tooth to replace one or more cusps. Onlay is comparatively bigger than an inlay but smaller than a crown. Onlays restore the function of eating all your favourite foods by replacing the biting surface of the tooth. Traditionally, onlays were made only of gold, but like inlays, more and more patients opt for the tooth colored restoration. Porcelain onlays has demonstrated their success due to their improved physical properties combined with the ability of the dentist to bond the restoration to the tooth. The enamel and dentin bonding for the onlay restoration, provides a strong bond and an excellent seal. As an onlay can also be used for covering the cusps of the tooth, it is considered as a conservative alternative to a dental crown. Onlay is the recommended restoration when the natural teeth are in a state beyond repair due to decay, infection, or accident. Onlay is the best way to retain natural tooth structure preventing decay or infection to spread further.
Inlays vs Onlays
Inlays and onlays vary in terms of size but in all other aspects of function are same. An inlay is smaller, filling a cavity that is confined to the area inside the tooth not involving the cusps . An onlay is larger, involving one or more cusps extending on to the tooth surface.They are indirect fillings.
When is an inlay the right choice?
Your dentist may recommend an inlay instead of the usual filling, -if the damage to the tooth is minimal and does not affect the cusp of the tooth. -If the damage to the tooth by caries or fracture or trauma etc necessitates a large dental filling that may weaken the remaining tooth structure. Composite resin and porcelain inlays are considered more durable than regular fillings of composite or amalgam. Inlays in comparison to regular fillings can help in increasing the tooth strength considerably. -insufficient amount of tooth structure left that doesn’t permit the placement of a crown.
What are the types of inlays?
An Inlay can be made of materials like gold, amalgam, porcelain or composite resin. Porcelain inlays offer natural tooth-like appearance and ability to blend with surrounding teeth. Gold is the most preferred material during the past as it is durable, strong, stain resistant and sustainable to wear and tear. The expensive nature of the precious metal gold makes it a less affordable option to the patients. However a gold inlay can last for 20 years or more.
Gold Inlays or fillings:
Gold was used in the past for its strength to protect teeth weakened by caries or trauma. But
today with the availability and cheaper cost of tooth colored restorations, gold is rarely used.
Gold inlays or onlays, are made of an alloy of gold, copper and other metals. They are most often
used when a cavity filling breaks down or chosen for use in the inconspicuous areas of the mouth
where appearance is not important, such as the posterior teeth or molars. Gold inlays/onlays can
be considered to be the most durable type of filling material often lasting 20 years or so, but also
can be expensive. Also patients need to plan for more visits to the dentist for the gold inlay or
On the other hand gold foil can be placed in a single visit by the dentist not involving any dental laboratory. This kind of gold restoration involves direct placement of gold called a gold foil. Gold foil dental restorations are preferred when the cavity is very small and not performed that often. Pros of gold fillings-strength and malleability: stain resistance; fracture resistance .Cons of gold fillings-color doesn't match natural tooth(esthetic issues) and high cost.
Ceramic inlays and onlays
They are made of porcelain to create tooth-colored restorations that mimic the color, shape, and function of natural teeth. Pros and cons of porcelain : Strong, durable, stain resistant, less prone to fracture than regular fillings. Esthetic and blends with the natural tooth color Cons:Though quite strong, the rigidity of porcelain puts it at risk of fracture. Porcelain is more fragile than gold inlays.
Composite inlays and onlays are used to fill cavities that are too large for regular fillings. Pros and cons of composite inlays : Excellent esthetics, precise and close fit, easy to use. They are a cheaper alternative to gold or ceramic restorations with similar functions. Compared to regular fillings they are stronger and less prone to fracture. Cons: Weak, less malleable than gold or porcelain, readily stains over porcelain.
Steps in the Inlay/Onlay Procedure -Removal of cavity filling
if need be Inlays and onlays may replace fractured or defective cavity fillings. In such cases, the dentist will remove the existing filling. A local anesthetic is given to numb the tooth while the dentist prepares the tooth to remove and clean out the decay. The resulting empty cavity is prepared and shaped for easy restoration with an inlay or onlay..
- Taking an Impression (inlay/onlay)
During the first visit, an impression of the tooth in need of restoration is taken by the dentist. At this stage the dentist will discuss with you the material of choice for the inlay or onlay(gold, ceramic, or composite). If in case ceramic inlay or onlay is decided upon, the shade of the restoration is also noted. The impression is then sent to the laboratory with instructions for Inlay/Onlay fabrication.
-Placement of Temporary filling
While the inlay or onlay is being prepared at the laboratory, a temporary filling is placed on the damaged tooth to seal the cavity. This helps prevent further decay, protects the tooth from sensitivity caused by cold or hot liquids and protects the weakened tooth structure from fracture.
-Placement of Inlay/onlay
After the lab delivers the custom fit restoration, the final step for the dentist is to place the
inlay/onlay in the tooth. To reduce pain or to minimise discomfort a local anesthetic may be
given by the dentist to numb the area. Then, the temporary filling material is removed and the
inlay or onlay is cemented into the tooth. The onlay is made to perfectly fit inside the tooth. A
laser is used to ensure a stronger bond. Inlays made from porcelain or composite resin material
are matched to the color of the tooth, and provide a natural look dental restoration while
repairing the chewing surface.
The entire procedure is simple and helps in retaining natural tooth structure. Local anesthetic helps keep the patient comfortable throughout.
CAD/CAM technology and Cerec have made porcelain and composite inlays and onlays possible for dentists just like same day crowns. In such cases, the entire procedure is completed in one single visit.
Onlay versus Crown
Onlay restoration is a conservative treatment involving retention of the natural tooth structure as much as possible. Only the tooth material affected due to decay or trauma are removed and replaced with onlay. Onlays cover one or more cusps of the damaged tooth thereby restoring tooth function. On the other hand, the fixture of the crown involves removal of more natural structure of the tooth and is an invasive procedure. Crown is more of a teeth replacement method ideal when the natural teeth are beyond repair due to decay, fracture, or trauma. Onlay restorations last longer than those teeth fitted with a crown. However both crown and onlays are restorative options to strengthen and enable the functioning of the teeth and oral health. However crown and inlay restorations can be affected by decay after sometime.
Benefits of inlays and onlays:
-More resistant to fractures and damage than regular cavity fillings. As inlays are bonded into
place, they hold teeth together unlike metal fillings which cause teeth to crack over time due to
-Stain-resistant unlike metal amalgam fillings that oxidize and turn black
-Ease of matching the tooth color and polishing to mimic the lustre of pearly tooth enamel improving the natural appearance.
-Custom made for a good fit a patient’s tooth structure, color, and shape thus preventing the infiltration of food as well as bacteria that causes decay.
-Long lasting, they can last up to 30 years if tooth is not at risk of caries or fracture.
-Inlays and onlays can add to the strength of a decayed or damaged tooth by up to 75 percent.
The adjustment period after an inlay and onlay restoration takes only a couple of days. To improve the lifespan of the restoration, one must practice a good oral hygiene routine. So as to reduce the chance of plaque build up and oral disease, the following tips are recommended-
Oral hygiene:Practices like brushing twice daily and flossing can’t be emphasized enough. Inlays extend into the interdental areas of your mouth and are difficult areas to clean. As such, they require regular interdental cleanings, with an interdental toothbrush and or floss.
Diet: Avoid highly acidic foods and drinks, foods that can cause staining and also reduce intake of sugary foods for promoting oral health.
Regular dental checkups:Routine dental check ups every six months are advised. Your dentist will examine the Inlays and onlays on these scheduled appointments. This is essential to spot any early signs of leakage, damage, and disease.
How Much Does an Inlay or Onlay Cost?
The cost of an inlay or onlay in gold can be quite high while that of composite is least expensive.The cost depends on the type of material used and skills of the dentist. At Smiline dental hospital, inlays and onlays are fabricated in our own dental laboratory.