Inlays and onlays are types of dental filling used to restore damaged teeth. When filling the inner tooth cavity the dental filling is referred to as an inlay. If filling the outer tooth cusp and structure, the dental filling is termed as an onlay.
Dental filler is used to fashion inlays and onlays. The type of dental filler may depend on the kind of tooth trauma involved, such as a cavity, fracture or worn tooth cusp. Restorative substances used as dental filler include dental composite and resins, porcelain, ceramics, gold, zirconium and amalgam.
People with tooth cavities, fractured teeth or teeth damaged due to tooth decay may be candidates for Inlays. Referred to as an indirect restoration, dental filler materials such as dental composite may be used to fill a tooth cavity. Alternatively, amalgam teeth fillings may be replaced by composite white filling inlays.
Porcelain or gold may also be a choice for inlays, which rebuild the tooth's inner structure for dental strength and bite function. Dental filler may also be used to restore a fractured tooth and can be moulded to reshape the tooth for a stronger finish.
Onlays may partly or fully cover a tooth when the tooth is broken, worn down due to teeth grinding or after a cusp fracture. Inlays and onlays are used to restore the outer tooth surface and structure and are custom-made according to the patient's oral dimensions and choice of material.
Dental composite and amalgam are not usually used for onlays, as stronger porcelain and gold alternatives are preferred. Onlays may be used instead of other more invasive treatment, such as dental crowns.
Inlay or onlay treatment involves a process of care to establish how best to treat the patient, according to their dental health and cosmetic needs. The treatment process involves:
A dentist evaluates a patient's oral health and uses diagnostic tests such as X-rays and imaging to identify the type of dental trauma and appropriate treatment. If treatment with inlays or onlays is necessary, the dentist will discuss the diagnosis and reasoning for the treatment with the patient. All risks, benefits and costs are transparently explained.
Dental moulds and impressions are made to obtain patient-specific measurements, to ensure accuracy in the design and fitting of the inlay or onlay filling.
For treatment with inlays or onlays, whether direct or indirect, the teeth are first cleaned and the traumatised tooth prepared to ensure no infection is present. In some cases of fracture, or where the tooth is severely broken, part of the tooth may be removed before it is filled or capped with an onlay.
Where "direct" treatment is involved the dentist may apply the dental filler for the inlay or onlay directly into the patient's mouth, using dental cement and a curing light for faster bonding. CEREC can sometimes be used to provide patient-specific inlays or onlays within one dental appointment.
If "indirect" the patient-specific dimensions from X-rays or imaging are sent to a laboratory along with the dental impressions, so that either the inlay or onlay is custom-made for the patient. Laboratory inlays and onlays are more hygienic and reduce the chances of marginal leakage due to their accurate design.
A temporary inlay or onlay is fitted while the dental laboratory technician sculpts the bespoke inlay or onlay according to the patient's measurements. These temporary inlays or onlays serve to protect the integral tooth structure and stop tooth sensitivity or further dental trauma.
A dental appointment is then made to bond the final inlay or onlay to the tooth using dental cement. When a curing light is used in indirect treatment, such as with CEREC, the inlay or onlay may be fitted within one sitting.
Once bonded to the restored tooth the inlay or onlay is polished for a smooth and natural feel. All rough surfaces are smoothed and streamlined so that no sharp edges are present, which could catch on the tongue or inner mouth tissues.
People suffering from dental anxiety or trauma should not let their fears prevent them from receiving the treatment they need. Relaxation solutions can help patients with dental phobia as can pain-free treatment options. A dentist can explain these options prior to treatment.
The type of restoration material used in dental inlays or onlays depends on where the tooth is located in the mouth and the extent of dental trauma. Dentists usually recommend the best suited material for certain treatments, such as gold inlays or onlays for broken upper molar teeth. The reason gold may be more suitable for this type of trauma is that it is strong and rarely fractures.
Gold or zirconium inlays or onlays may be more suitable for those with misaligned bite caused by teeth grinding or bruxism. These materials are less likely to fracture during teeth grinding. However, they may be less aesthetically pleasing to alternatives such as porcelain.
To improve oral function and maintain beautiful, natural smiles porcelain, zirconium or resin inlays or onlays may be used for visible teeth. These materials are also less likely to discolour than white composite fillings, which are not entirely stain resistant.
White fillings are also a form of dental restoration. However, they are comprised of dental composite and resin. White composite fillings are only appropriate for filling smaller tooth cavities, whereas other materials are able to bridge larger holes.
Composite white fillings have a tendency to shrink or become worn when in contact with other teeth, which means they have to be replaced quite often. Inlays and onlays are more suited to larger cavities or fractures requiring precision filling. The accuracy of their design and finish means inlays and onlays reduce the likelihood of gum irritation and tooth sensitivity. The use of light-activated curing also means that the inlay or onlay is shaped, cured and polished to completion without the risk of further shrinkage.
The dentist polishes the final inlay or onlay so that it is smooth to the touch and looks as healthy as your natural teeth. Your dentist will recommend regular teeth flossing and brushing to maintain the health of your teeth. Using an anti-bacterial mouthwash also helps to keep the breath fresh and reduce the risk of tartar and plaque build-up.
Treatment with inlays or onlays can provide patients with numerous benefits, such as:
Dentists trained in cosmetic dentistry have the combined aesthetic and dental expertise to provide inlay and onlay treatment. Trained in the use of cutting-edge technology, modern restorative materials and advanced procedures, these practitioners possess the necessary skill and artistic ability to create strong and functional dental restorations, such as inlays and onlays.
The cost of inlay and onlay treatment depends on the level of treatment required and whether or not oral infection or decay is present. Due to durability and the need for fewer dental appointments, inlays and onlays can be cost-effective compared to alternative treatments like white fillings.
Inlays & Onlays information for further reading.