Understanding the Facial Features & Smile Line in Complete Dentures

When we talk about complete dentures, the conversation usually goes straight to the big clinical records.

• The impression.
  
• The bite registration.
• The vertical dimension.
• The occlusion.
• The shade.
• The mould.
  
  

All of these are important. In fact, without them, the denture journey can go from smooth sailing to “why does this look like it belongs to someone else?” very quickly.

But there is one record that is often missed, and in our experience at Bremadent Dental Laboratory, it can make a huge difference to the final appearance of a denture.
The smile line.

Also known as the high lip line, and when combined with the low lip line, it gives the dental laboratory a much clearer understanding of how the patient actually displays their teeth when speaking, smiling and resting. It is one of those small clinical records that takes seconds to mark but can save a lot of guesswork later.

The Laboratory Cannot See the Patient Smile
This is the part that is easy to forget. As a dental laboratory, we receive impressions, bite registrations, photographs if provided, prescriptions and sometimes additional notes. What we do not usually see is the patient sitting in the chair, smiling naturally, laughing, speaking or resting.

1. A model does not smile.
2. A bite rim does not laugh.
   
   

An impression does not tell us whether the patient shows a lot of tooth, very little tooth or a full display of gingiva when smiling. That information must come from the clinical records.

When the high and low lip lines are marked onto the upper bite registration, it gives the technician a visual guide to how the final denture should sit within the patient’s face. Without it, the technician has to make an educated judgement based on average principles, photographs or experience.

That can still produce a good denture, but it is not the same as having the patient’s own facial landmarks clearly recorded.

What Is the Smile Line?
The smile line is the position of the upper lip when the patient gives a natural or full smile.
In denture construction, this is usually recorded as the high lip line.

The high lip line shows the highest point the upper lip reaches when the patient smiles. This tells the technician how much tooth and gingival contour may be visible.

The low lip line is the position of the lip at rest. This helps show how much of the anterior teeth should be visible when the patient is relaxed or speaking naturally.

Together, the high and low lip lines help guide the visible display of the denture.
They help determine:
• How much tooth should be shown at rest.
• How much tooth should be shown when smiling.
• Whether the patient naturally shows gum.
• Where the gingival margins should be positioned.
• How much wax should be added around the necks of the teeth.
• How much cervical contouring can be created.
• Whether root prominence and gingival anatomy will enhance or harm the final appearance.

That is a lot of information from two simple marks. Not bad for something that takes less than a minute.

Why the Smile Line Matters So Much
A complete denture is not just a row of teeth set into acrylic. It is part of the patient’s face.

That means it has to work with the lips, cheeks, smile, facial muscles, speech and personality of the patient.
If the teeth are set too low, the patient may show too much tooth and the denture can look artificial.

If the teeth are set too high, the patient may show very little tooth and the denture can make them appear older or more collapsed.

If too much wax or acrylic is added around the cervical necks, it may show when the patient smiles.
If too little contouring is added, the denture can look flat, lifeless and false.

The smile line helps the technician make better decisions with the anterior setup and gingival contouring.
It gives us a guide for how to make the denture look natural to that individual patient, not just technically correct on the bench.

Facial Features Are the Aesthetic Blueprint
At Bremadent Dental Laboratory, we see facial features as the aesthetic blueprint for complete denture construction.
The bite registration gives us functional information. The facial markings give us aesthetic information. Both are needed.

Facial features help set the parameters for the anterior teeth, including mould size, shape, width, height and tooth positioning.

These features should ideally be scribed onto the upper bite registration using a cold wax knife. A hot wax knife should not be used intra-orally because it can injure the patient and may distort the wax rim. The aim is to record the information clearly and safely, not give the patient an unexpected hot wax experience they definitely did not book in for.

The key facial records include:
• Centre line.
• Canine lines.
• High lip line.
• Low lip line.

Together, these records help the dental technician arrange the teeth in accordance with the patient’s own facial orientation.

The Centre Line
The centre line, often called the midline, is one of the most important guides for positioning the upper central incisors.
A common mistake is using the nose as the guide.

The problem is that the nose is not always central to the face. In many patients, the nose can be slightly skewed or asymmetrical. If the nose is used as the main reference, it can give a false reading and the central incisors may end up looking off-centre.

The philtrum is usually a better guide for the facial midline.

Using the philtrum allows the clinician to record a more reliable centre line, helping the laboratory position the upper central incisors in harmony with the patient’s face.

When the midline is correct, the denture immediately looks more balanced.

When it is wrong, even slightly, patients often notice. They may not know exactly what is wrong, but they will feel that something looks uneven.

The Canine Lines
The canine lines help determine the width of the anterior tooth setup. In many patients, the width of the nose gives a useful guide for the canine position. This is a common relationship in facial anatomy and works well as a starting point for many complete denture cases.

The canine lines help the laboratory select the correct anterior mould width and position the teeth within the patient’s natural facial proportions.

As a general guide, the body or labial mesial surface of the canine should sit on or just beyond the canine line. This helps create a natural alignment and prevents the anterior teeth from appearing too narrow or too wide for the patient’s face.

Of course, dentistry is not always textbook. Patient preference, old photographs, previous dentures, facial asymmetry and clinical judgement may all influence the final canine position.

But without canine lines marked on the bite rim, the technician has to estimate the width of the anterior setup. That estimate may be close, but it will never be as useful as properly recorded clinical information.

The High Lip Line
The high lip line is recorded when the patient gives their biggest natural smile. This is the smile line.
It shows the highest point reached by the upper lip and tells the technician how much of the anterior teeth and gingival area may be visible. This is critical when setting up complete dentures because it helps determine how much wax should be added around the necks of the teeth.

For example, if the patient has a high smile line and shows a lot of gingiva, the wax contouring and gingival anatomy become much more visible. In that situation, the technician must be careful with the shape, bulk and finish of the cervical areas.

If the patient has a low smile line and does not show much gingiva, the technician may have more freedom with contouring because less of the gingival area is visible during function and smiling. This information helps create a denture that looks natural in the mouth, not just neat on the model.

The Low Lip Line
The low lip line is recorded when the lips are at rest. This is just as important as the smile line because many patients judge their denture appearance not only when smiling, but also when speaking, relaxing and looking in the mirror.
The low lip line helps determine how much incisal edge should be visible at rest.

Too much tooth display at rest can look unnatural. Too little tooth display can make the patient look aged or overclosed.
When the high and low lip lines are recorded together, the laboratory gains a much better understanding of the patient’s natural tooth display.

That allows the setup to be more controlled, more personal and more predictable.

Why Many Dentures Look Artificial
A denture can be technically well made and still look artificial. This usually happens when the teeth and gingival contours do not match the patient’s face.

Common reasons include:
• No smile line recorded.
• No low lip line recorded.
• Midline marked from the nose instead of the philtrum.
• Canine lines not marked.
• No photographs provided.
• Tooth mould selected without facial guidance.
• Too much wax added around the necks.
• Not enough cervical contouring.
• Teeth positioned using averages rather than patient-specific landmarks.

This is why small clinical records matter. A complete denture is not just about replacing missing teeth. It is about restoring appearance, confidence, speech, function and facial support.

The more information the laboratory receives, the more natural and predictable the outcome can be.

How the Smile Line Helps Gingival Contouring
One of the most underappreciated parts of denture aesthetics is the wax-up around the cervical necks of the teeth. This area can completely change the final appearance.

Good gingival contouring can make teeth look like they emerge naturally from the tissues. Poor contouring can make teeth look stuck onto a pink plate.

The smile line tells the technician how visible this area will be. If the cervical areas are going to show during smiling, they need more careful anatomical shaping. This may include subtle root form, papilla shape and natural contouring around the necks of the teeth.

If the cervical areas are not visible, the approach may be slightly different, with more focus on support, hygiene and function.

This is why the smile line is not just a cosmetic extra. It directly affects how the laboratory shapes the denture.

It Only Takes Seconds to Record
One of the most frustrating things about missing smile lines is that they are so quick to record.
A simple clinical routine could look like this:
• Seat the upper bite rim correctly.
• Confirm the vertical dimension and lip support.
• Ask the patient to relax and mark the low lip line.
• Ask the patient to smile naturally.
• Ask for a full smile and mark the high lip line.
• Mark the centre line using the philtrum.
• Mark the canine lines using the width of the nose as a guide.
• Add notes if old photographs, patient preference or facial asymmetry affect the setup.

This small step gives the laboratory a huge amount of useful information.

• It can improve the try-in.
• It can reduce adjustments.
• It can make the final denture look more natural.

Most importantly, it helps the patient feel that the denture belongs to them.

What We See at Bremadent Dental Laboratory
At Bremadent Dental Laboratory, we work with many dental practices and dental teams across the UK, and we see a wide range of denture cases every day.

Some bite registrations arrive beautifully marked, with centre line, canine lines, high lip line, low lip line, shade, mould guidance and clear prescription notes.

Those cases are much easier to plan. Other bite rims arrive with very limited markings. In those cases, the technician has to rely more heavily on experience and general denture principles.

Experience matters, but clinical records matter too. The best results usually come when the dentist, clinical dental technician and dental laboratory work together as one team.

When the laboratory receives the right information, the technician can spend more time making the denture excellent and less time trying to work out what the patient looked like in the chair.

That is better for everyone.

Better Records Save Chairside Time
Good laboratory communication is not just about making things look nice.
It also saves time.

When the smile line and facial features are recorded clearly, the try-in appointment becomes more predictable. The clinician can assess the setup with confidence because it has been created using patient-specific information.

This can help reduce:
• Tooth repositioning at try-in.
• Excessive anterior adjustments.
• Patient dissatisfaction with appearance.
• Remakes caused by poor aesthetic communication.
• Additional appointments.
• Unnecessary chairside stress.

Nobody wants the try-in appointment to become a negotiation about why the patient suddenly looks surprised, tired or like they have borrowed someone else’s teeth.

A few simple markings at the bite stage can prevent a lot of that.

The Patient Does Not Judge the Denture on the Bench
This is a key point. Technicians often view dentures on an articulator or model. Patients view dentures in their face.
That means the final result must be judged in relation to the lips, smile, facial movement and expression.

A setup can look symmetrical on the bench but still not suit the patient. The smile line helps bridge that gap between the laboratory bench and the patient’s face.

It gives the technician a better understanding of how the denture will appear in real life, not just under a bench light.

The smile line may seem like a small record, but in complete denture construction it can have a major impact.

• It helps guide tooth display.
• It helps determine gingival contouring.
• It helps the technician understand the patient’s facial dynamics.
• It reduces guesswork.
• It supports better communication between the dental practice and the dental laboratory.
  
  

Most importantly, it helps create dentures that look natural, balanced and individual to the patient. At Bremadent Dental Laboratory, we believe that excellent dentures are built from excellent records. The impression, bite registration and occlusion matter, but so do the facial features that guide the final appearance.

The centre line, canine lines, high lip line and low lip line are simple to record, but they provide the laboratory with information that cannot be guessed accurately from models alone.

So, the next time a complete denture case is at the bite stage, take those few extra seconds to mark the facial features clearly. Your dental technician will appreciate it. Your try-in appointment will be smoother.

And your patient is far more likely to look in the mirror and say the words every dental team wants to hear.
“They look like my teeth.”

We provide a trusted laboratory service delivering consistent quality, saving chairside time, and supporting predictable patient outcomes.

📞: 0208 520 8528 

 📧: [email protected] 

📍: 25A St James Street, London, E17 7PJ