Most people are familiar with fillings and crowns. A filling repairs a small cavity. A crown covers the entire tooth when the damage is more serious. But there’s a middle option that many patients have never heard of until their dentist brings it up: the onlay.
It’s sometimes called a partial crown, and the name is fairly accurate. Understanding what it is and when it makes sense can help you have a more informed conversation at your next appointment at Linden Market Dental Centre in Winnipeg.
What an Onlay Actually Is
An onlay is a custom-made restoration that covers part of a tooth’s biting surface, including one or more of the raised points called cusps. It’s fabricated in a dental lab or, in some cases, milled chairside using CAD/CAM technology, then bonded permanently to the tooth.
It sits somewhere between a filling and a crown in terms of how much tooth it covers. A filling repairs damage within the tooth’s natural boundaries. A crown caps the entire tooth down to the gumline. An onlay covers the chewing surface and extends over one or more cusps, but leaves the sides of the tooth largely intact.
The closely related term “inlay” refers to the same type of restoration when it fits within the cusps without covering them. Onlays go further, covering at least one cusp. Both are made the same way and serve the same general purpose: restoring a damaged tooth while preserving as much of the natural structure as possible.
When a Tooth Needs an Onlay Rather Than a Filling or Crown
This is usually the decision that surprises patients. They come in expecting a tooth-coloured dental fillings, and the dentist recommends something different.
A filling works well when decay is contained, and the surrounding tooth structure is solid enough to hold it. When damage is more extensive, a standard filling may not have enough healthy tooth to bond to properly. It can also flex differently from the natural tooth under biting pressure, which creates a cracking risk over time.
A dental crown removes a significant amount of tooth structure to create clearance for the cap. When a tooth is healthy enough on the sides and base, removing that structure unnecessarily is not ideal. The more natural teeth you can preserve, the better the long-term health of that tooth.
An onlay fits the situations in between:
- Decay or damage that covers too much of the chewing surface for a filling to hold reliably
- A cracked cusp where the crack doesn’t extend down into the root
- A tooth with an old, large filling that has failed and the surrounding enamel is compromised
- A tooth where a crown would require removing structure that is still healthy and intact
Dr. Morgan Winchar at Linden Market Dental Centre assesses each case individually. The goal is always to do the minimum necessary to restore the tooth to full function while preserving what’s there.
What Onlays Are Made From
Most onlays today are made from tooth-coloured materials, either porcelain or composite resin. Both are designed to match the natural shade of the tooth so they’re not visible during normal conversation or eating.
Porcelain onlays are durable and hold their colour well over time. They’re a good match for back teeth that handle a significant chewing load. Composite resin onlays can also perform well and are sometimes completed in a single appointment, depending on the technology available.
Gold onlays are still used in some clinical situations. Gold is exceptionally durable and causes less wear on opposing teeth than some ceramics. It’s less common now simply because of aesthetics, but for some patients and some tooth locations, it remains a reasonable choice.
The CEREC Advantage at Linden Market Dental Centre
One of the practical considerations with dental inlays and onlays in Winnipeg is that they traditionally required two appointments: one to prepare the tooth and take impressions, and a second to fit the finished restoration after it returned from the dental lab. A temporary restoration sits in place between visits.
Dr. Winchar uses CEREC technology at Linden Market Dental Centre, which allows same-day onlays and crowns for many cases. The tooth is scanned digitally, the restoration is designed on screen, and it’s milled chairside from a ceramic block in a single visit. No impressions, no temporary, no second appointment.
Not every case is suited to chairside milling. Some situations still benefit from a lab-fabricated restoration. Dr. Winchar will advise which approach makes more sense for your specific tooth and the type of restoration needed.
How Long Do Onlays Last?
With proper care, a well-placed onlay can last 10 to 30 years. The range is wide because longevity depends on several factors:
- The material used and how much chewing load the tooth handles
- Whether the patient grinds their teeth (a night guard helps significantly)
- Oral hygiene habits and how regularly the patient comes in for cleanings
- Whether any new decay develops around the margins of the restoration
The bonding between the onlay and the tooth surface is one of its strengths. When seated properly and maintained well, the bond is tight enough that bacteria struggle to get underneath, which reduces the risk of secondary decay compared to older-style restorations.
What to Expect During the Appointment
If Dr. Rykiss or Dr. Winchar recommends an onlay, here’s what the appointment typically involves:
- Local anesthetic to numb the area
- Removal of the damaged or decayed portion of the tooth
- Shaping the tooth to receive the onlay
- A digital scan or impression of the prepared tooth
- Fabrication of the restoration, either chairside with CEREC or at a dental lab
- Bonding the finished onlay to the tooth and checking the bite
The tooth will be sensitive for a few days after placement as it adjusts. Avoiding very hard or sticky foods during that initial period helps the restoration settle in properly.
Book an Appointment at Linden Market Dental Centre in Winnipeg
If you’ve been told you need a large filling replaced, or if a tooth has been causing intermittent discomfort that hasn’t been investigated, an exam at Linden Market Dental Centre is a good starting point. Dr. Winchar and Dr. Rykiss will assess what’s going on and walk you through the options that make sense for your tooth specifically.
The clinic is a dental clinic in Winnipeg that accepts new patients and CDCP coverage. Online booking is available for new patient exams and hygiene appointments.
Call (204) 487-2226 or book an appointment online. Linden Market Dental Centre is at 877 Waverley St, Unit 7, Winnipeg, MB, and serves patients from Linden Woods, Whyte Ridge, Fort Garry, South Pointe, and surrounding areas.
