A bite block is a wax device your dentist uses to map the exact relationship between your upper and lower jaws before your dentures are made. It looks like a pink, horseshoe-shaped ridge of wax mounted on a temporary base that fits over your gums. Without it, a dental lab would have no way of knowing where to position your new teeth for a comfortable bite, natural appearance, and clear speech.
If you’re in the process of getting dentures, the bite block appointment is one of the most important steps. It’s the bridge between taking impressions of your mouth and actually building the dentures you’ll wear every day.
How a Bite Block Works
A bite block consists of two parts: a rigid baseplate (usually made from shellac, resin, or a stiff thermoplastic) that sits snugly on your gums, and a wax rim built on top of it. The wax rim stands in for the teeth that haven’t been placed yet, giving your dentist a moldable surface to shape, mark, and adjust.
When you bite down on the wax rims, your dentist captures a three-dimensional record of how your jaws line up. This tells the lab several things at once: how far apart your jaws sit when you’re at rest (the vertical dimension), how your lower jaw centers relative to your upper jaw, and how much space the artificial teeth need to fill. Primary impressions alone can’t capture any of this because they only record the shape of your gums, not how your jaws move and meet.
What Happens at the Appointment
The bite block step typically falls early in the denture process, after impressions have been taken but well before you see anything resembling finished teeth. Your dentist will place the upper and lower bite blocks in your mouth and begin adjusting the wax rims, trimming or adding wax until the height, width, and contour feel right.
You’ll be asked to close your mouth, swallow naturally, and bite together in a relaxed position so your dentist can record what’s called centric relation, the most stable and centered position of your lower jaw. Some dentists mark this position directly in the wax. Others use a small tracing device that tracks your jaw movements and pinpoints the ideal bite position with high precision. Either way, the goal is to lock in a jaw relationship that feels natural and repeatable.
Beyond the bite itself, your dentist uses this appointment to capture a surprising amount of cosmetic information. They’ll check whether the wax rim properly supports your lips, giving your face its natural fullness rather than a sunken look. They’ll mark the midline of your face on the wax so the lab can center the front teeth symmetrically. They’ll draw a vertical line from the edge of each nostril down to the wax to show where the corner teeth (canines) should sit. And they’ll ask you to give your widest smile so they can scribe your high smile line onto the rim. The distance from that line to the bottom of the wax tells the lab exactly how long to make the front teeth, typically about 1mm longer than the measured distance so they peek out naturally when you smile.
This is also when tooth shade and shape are selected. Your dentist may hold shade guides next to your skin and the wax rim to pick a color that looks natural, and choose a tooth mold that suits the size and shape of your face. The whole appointment is usually relatively quick, though the precision involved means your dentist will take their time getting each measurement right.
Why Accuracy Matters So Much
Every measurement taken on the bite block directly affects how your finished dentures feel, function, and sound. If the vertical dimension is set too high, your jaws will be forced apart slightly, leading to muscle fatigue, soreness, and a strained appearance. Set it too low, and your face can look collapsed, with your chin sitting too close to your nose.
A poorly recorded bite relationship causes problems you might not immediately connect to the dentures themselves. Teeth that don’t meet evenly can produce clicking or whistling sounds when you speak. Misalignment can interfere with tongue placement, making certain sounds difficult to pronounce clearly or causing slurred, mumbled speech. Dentures built from inaccurate bite records may also rock or shift on your gums during chewing, accelerating sore spots and bone loss over time.
Getting the bite block stage right means fewer adjustments later. When the wax rim records are precise, the trial denture (a wax preview of your final set) is far more likely to fit well on the first try.
The Try-In Stage That Follows
Once the lab receives your bite blocks along with all the marked measurements, they mount stone models of your gums on a mechanical device that mimics your jaw movements. Using this setup, they arrange artificial teeth in wax according to the positions your dentist specified. The result is a trial denture, sometimes called a wax try-in, that you’ll test at your next appointment.
During the try-in, you’ll check how the teeth look when you smile, whether the bite feels balanced, and whether the lip support is right. Most of the time the fit is close to final. Occasionally a second try-in is needed to fine-tune the look or comfort before the lab processes the permanent denture in hard acrylic.
Digital Alternatives to Traditional Bite Blocks
Digital denture workflows are changing parts of this process. Instead of traditional impression materials, some dental offices now use intraoral scanners to capture the shape of your gums as a digital file. Specialized design software then maps out tooth position, bite alignment, and fit on a virtual model, reducing some of the manual steps involved with physical wax rims.
That said, recording how your jaws relate to each other still requires some form of physical reference in your mouth, whether that’s a conventional wax bite block or a digitally guided equivalent. The digital workflow’s main advantage is precision at the manufacturing stage: once the design is finalized, a milling machine carves the denture from a solid block of pre-cured, high-density acrylic, which tends to be denser and more consistent than traditionally processed material. The result is often fewer adjustment appointments and a more predictable fit, though the core purpose of the bite registration step remains the same regardless of whether the process is analog or digital.