A collapsed bite occurs when the vertical distance between your upper and lower jaws shrinks, usually because teeth have been worn down, lost, or both. Dentists call this a loss of “vertical dimension of occlusion,” and it affects everything from how your face looks to how well you chew. Fixing it involves first figuring out how much height has been lost and why, then gradually rebuilding that height with restorations, prosthetics, orthodontics, or sometimes surgery. The process is more nuanced than simply adding material to your teeth, and the diagnostic phase matters just as much as the treatment itself.
What Actually Causes a Bite to Collapse
The loss of vertical dimension rarely has a single cause. A comprehensive review in prosthodontic literature identified a wide range of contributors, including pathological tooth wear from erosion, attrition, and abrasion; tooth loss with collapse of posterior support; parafunctional habits like clenching and grinding; iatrogenic factors from prior dental work; and even systemic or pharmacological causes.1PubMed Central. Vertical Dimension in Prosthodontics Theory and Practice (Part III): Contemporary Clinical Protocols and Decision-Making for Loss of Vertical Dimension of Occlusion In practice, these factors often overlap. Someone who grinds their teeth at night and also drinks a lot of acidic beverages, for example, gets hit from two directions at once.
Bruxism deserves special mention because it is considered one of the most destructive functional disorders affecting the teeth. When combined with acid erosion from diet or gastric reflux, the damage accelerates considerably.2PubMed Central. Aesthetic Rehabilitation in Teeth with Wear from Bruxism and Acid Erosion In severe cases, a patient can lose dramatic amounts of tooth structure. One reported case involved a young adult with bruxism and severe erosive wear who had lost enough tooth height to create an 8-mm gap between their resting jaw position and their biting position.3PubMed Central. Minimally Invasive Oral Rehabilitation Using 3D-Printed Resins in a Patient With Severe Dental Erosion and Bruxism Eight millimeters is a lot of lost vertical space and represents an extreme collapse.
Loss of back teeth is another common route. Your molars and premolars act as pillars holding your bite open at the correct height. When several of them are extracted and not replaced, the remaining teeth cannot maintain that vertical support. Over time the jaw closes further than it should, and the bite gradually collapses.
How to Tell if Your Bite Has Collapsed
Some signs are visible in the mirror. The lower third of your face may look shorter or more compressed than it used to. Deep creases can form around the mouth, and the chin may appear to rotate forward and upward. Overclosure of the mouth creates a characteristic “sunken” appearance that people sometimes attribute to aging alone when the real culprit is lost tooth height.
One specific and sometimes surprising symptom is angular cheilitis, the cracked, sore skin at the corners of your lips. When the vertical dimension of the jaws is reduced, the mouth overclosed, and saliva pools and stagnates at the lip corners, eventually breaking down the skin and mucosa there.4Scientific Research Publishing / SciDoc Publishers (International Journal of Dentistry and Oral Science). Angular Cheilitis – An Updated Overview of the Etiology, Diagnosis, and Management If you have persistent cracking at the corners of your mouth that does not respond to lip balm or antifungal cream, a collapsed bite may be part of the reason.
Functional symptoms matter too. Chewing may feel less efficient. You may notice more strain or fatigue in your jaw muscles, particularly after meals. Some people develop sensitivity in their front teeth because those teeth are now absorbing forces that the missing or worn-down back teeth used to handle.
How Dentists Diagnose the Problem
Determining how much vertical dimension you have lost, and how much needs to be restored, is trickier than it sounds. There is no single measurement that definitively tells a clinician “this is where your bite should be.” Instead, diagnosis relies on combining several lines of evidence.
One important tool is cephalometric analysis, a standardized method of assessing dental and skeletal proportions using a lateral X-ray of the skull. Cephalometry can establish an individual pattern for each patient, helping the dentist understand the relationship between the lower face height and the shape of the jawbone.5PubMed Central. Cephalometric approach to the occlusal vertical dimension reestablishment A large study of over 500 adults found that the angle of the mandible correlated meaningfully with lower facial height, though the relationship was not tight enough to be perfectly predictive on its own.6PubMed. Cephalometric estimation of vertical dimension of occlusion In other words, cephalometrics gives the clinician useful guidance, but not an exact blueprint.
Clinical measurements supplement the X-rays. One approach uses what is called the Shimbashi number, essentially a measurement between specific anatomical landmarks on the upper and lower front teeth when you bite down. In a study comparing patients with jaw disorders to healthy controls, clinicians measured both the Shimbashi number and the distance between the enamel-root junctions of upper and lower teeth on radiographs, then combined these findings with cephalometric analysis to evaluate vertical height reduction.7PubMed. Evaluation of vertical facial height reduction and severity of temporomandibular joint disorders using Shimbashi number and cephalometric analysis The idea is to triangulate from multiple measurements rather than trust any single one.
Beyond imaging and numbers, the dentist also evaluates your speech, your lip support, the space between your teeth when your jaw is at rest, and how your facial muscles behave. Old photographs can sometimes help establish what the lower face looked like before the vertical loss occurred. Mounted study models on an articulator, a mechanical device that simulates jaw movement, let the treatment team plan exactly how much height to add and where.
Why a Trial Phase Comes First
Before committing to permanent restorations at a new, taller bite, most treatment plans include a provisional or evaluation phase. The purpose is to test whether your jaw, muscles, and joints can tolerate the increased vertical dimension before anyone starts cutting or bonding permanent crowns.
Traditionally this trial is done with a removable splint, often made from acrylic, worn on the upper teeth for a period of weeks to months. In one clinical protocol, a splint was designed to be worn full-time except during meals and hygiene, and the patient was monitored for three months for any signs of jaw joint problems, muscle tenderness, or excessive wear on the appliance.8International Journal of Prosthodontics and Restorative Dentistry. Clinical Considerations while increasing Occlusal Vertical Dimension If nothing goes wrong during that window, the clinician gains confidence that the new bite height will be tolerated long-term.
However, removable trial devices have real drawbacks. A systematic review looking at the evidence on evaluation phases found that removable devices tend to cause chewing difficulties, unclear speech, and cosmetic discomfort, and concluded that a removable appliance was not well-suited for functionally or aesthetically evaluating the new bite height prior to definitive treatment.9PubMed Central. Importance of an Evaluation Phase When Increasing the Occlusal Vertical Dimension: A Systematic Review The alternative is using fixed provisional restorations, which are temporary crowns or onlays bonded directly to the teeth. These feel more natural, let you chew and speak normally, and give a more realistic preview of what life at the new bite height will be like. The trade-off is more chair time and expense during what is still just the test phase.
Will Raising the Bite Hurt Your Jaw Joints?
This is probably the most common worry patients have, and the evidence is more reassuring than many people expect. A literature review on whether altering the vertical dimension produces jaw joint disorders concluded that the available evidence, while not especially strong, points toward the jaw system adapting rapidly to moderate changes. Some patients experience mild, temporary symptoms, but these tend to be self-limiting and without lasting consequence.10PubMed. Does altering the occlusal vertical dimension produce temporomandibular disorders? A literature review
An earlier review reached a similar conclusion, finding that current scientific knowledge does not support the idea that moderate changes in vertical dimension are harmful to the chewing system, provided the increase is not extreme and the appliance covers most of the teeth.11The Journal of Prosthetic Dentistry. Relationship of occlusal vertical dimension to the health of the masticatory system A scoping review that surveyed practicing dentists confirmed this picture: while many clinicians test a new bite height out of caution, a large majority observed that patients typically adapt well regardless of the technique used, and the literature found no direct causal or curative link between changing the vertical dimension and jaw joint disorders.12Wiley Online Library. Myths surrounding vertical dimension of occlusion in restorative dentistry: A scoping review
In fact, raising the bite can actually help with muscle pain. In one study, occlusal splints at three different heights were tested on 75 patients. Splints built at around 4 mm and 8 mm of opening produced faster and more complete relief of muscle-related pain symptoms than splints at just 1 mm. Stretching the jaw-closing muscles closer to their position of least electrical activity seemed to promote relaxation rather than strain.13The Journal of Prosthetic Dentistry. Influence of the vertical dimension in the treatment of myofascial pain-dysfunction syndrome So for people whose collapsed bite has contributed to chronic clenching and facial soreness, restoring height may actually be part of the relief.
Restorative Options for Rebuilding Height
Once the trial phase confirms you tolerate the new vertical dimension, definitive treatment can take many forms depending on what is left to work with. The key principle is the same regardless of materials: restore enough tooth height to re-establish proper vertical support while distributing chewing forces evenly.
For patients who still have most of their teeth but with generalized wear, full-mouth rehabilitation with bonded ceramic restorations is a common approach. A clinical algorithm described for patients with severe, generalized tooth wear included functional crown-lengthening surgery where needed to expose more tooth structure, followed by adhesively bonded lithium disilicate crowns and layered ceramics.14PubMed Central. A Clinical Algorithm for Full-Mouth Rehabilitation in Patients With Generalized Severe Tooth Wear: A Case Report Crown lengthening is a minor gum surgery that removes a small amount of bone and soft tissue to create a taller visible tooth, giving the crown something to grip onto. Only teeth that have been worn so severely that they lack sufficient structure need this step; in one case, just two canines required the procedure to achieve adequate clinical crown length.15The Journal of Advanced Prosthodontics. Full mouth rehabilitation of the patient with severely worn dentition: a case report
Newer minimally invasive approaches use bonded composite or 3D-printed resin restorations that add height without grinding away much remaining enamel. These work well for younger patients whose teeth are worn but not yet broken down enough to need full crowns. The case of the young patient with 8 mm of vertical loss, mentioned earlier, was treated using 3D-printed resin restorations in a minimally invasive protocol.3PubMed Central. Minimally Invasive Oral Rehabilitation Using 3D-Printed Resins in a Patient With Severe Dental Erosion and Bruxism The appeal is that less tooth structure is sacrificed, but these restorations may not last as long under heavy grinding forces and could need replacement over time.
When posterior teeth are missing entirely, the plan may include implant-supported restorations or bridges to rebuild the pillars of the bite. In complex cases, implants can even be placed strategically before other treatment to re-establish a stable posterior stop. One such case involved a patient with skeletal jaw asymmetry and posterior bite collapse who received dental implants first, then orthognathic surgery to correct the jaw position; the result was stable after six years of follow-up.16Implant Dentistry. Oral Rehabilitation With Orthognathic Surgery After Dental Implant Placement for Class III Malocclusion With Skeletal Asymmetry and Posterior Bite Collapse
Digital Workflows Are Changing the Process
Treatment planning for a collapsed bite has historically been an analog process: physical impressions, plaster models, wax buildups, and manual articulators. Digital technology is starting to replace several of those steps. In a fully digital workflow, an intraoral scanner captures a 3D impression of the teeth, and a jaw-tracking device records how the lower jaw actually moves during opening and closing. Those movements can be replayed frame by frame on a computer, allowing the clinician to visualize the ideal new bite height in a virtual environment and design the restorations digitally before any material touches the teeth.17Journal of Dentistry. A completely digital approach to increase occlusal vertical dimension in centric relation for fixed full-mouth rehabilitation
Does the digital approach actually match the traditional one in accuracy? A clinical study compared bite registrations taken with a jaw-tracking device against conventional intraoral scanning methods when planning complete-arch rehabilitations at an increased vertical dimension. The study found that both protocols produced trial restorations with comparable bite accuracy and patient satisfaction, and concluded that virtual determination of the jaw relationship using jaw tracking was a reliable option.18The Journal of Prosthetic Dentistry. Reliability of planned occlusal contacts in complete arch rehabilitations at increased vertical dimension: A clinical comparison of intraoral scanning and jaw tracking protocols Digital planning also makes it easier to 3D-print provisional restorations or splints for the trial phase, shortening turnaround time and improving the fit of test restorations.
When Surgery Enters the Picture
Most collapsed bites can be managed restoratively. But when the collapse is tied to a skeletal problem, such as a jaw that is too small, too far back, or asymmetric, restorations alone cannot fully correct the issue. In those situations, orthognathic surgery may be needed to reposition the bones of the jaw before or alongside the restorative work. As the case described above illustrates, combining implant placement with corrective jaw surgery can produce outcomes that remain stable for years.16Implant Dentistry. Oral Rehabilitation With Orthognathic Surgery After Dental Implant Placement for Class III Malocclusion With Skeletal Asymmetry and Posterior Bite Collapse
Surgical cases are the exception, not the rule. They tend to involve younger patients with developmental skeletal discrepancies or older patients whose bite collapse is part of a broader pattern of jaw deformity. The vast majority of people with a collapsed bite from wear or tooth loss will be treated without surgery.
The Effect on Chewing, Confidence, and Daily Life
It is worth acknowledging how much a collapsed bite affects quality of life. Beyond the mechanical problem, people with a severely reduced bite often experience physical pain, difficulty eating certain foods, and self-consciousness about their appearance. Research on patients who have had part of their jawbone removed, an extreme form of bite loss, found substantial declines in bite force and measurable psychological discomfort, with quality-of-life scores reflecting both pain and emotional impact.19Research Reports in Oral and Maxillofacial Surgery. Impact of Mandibulectomy on Bite Function and Oral Health-Related Quality of Life: A Pilot Study Even in less dramatic cases, restoring the bite height tends to improve chewing ability, facial appearance, and overall satisfaction.
Full-mouth rehabilitation is a significant investment in time, money, and dental visits. Treatment can stretch over months or even a year when it includes orthodontics, surgery, or a lengthy provisional phase. But the functional and psychological payoff is often dramatic. One rehabilitated patient whose posterior teeth were rebuilt reported improved chewing ability along with a stable, physiologically sound bite, and was satisfied enough after the provisional period to move ahead with permanent restorations.20Journal of Dental Rehabilitation and Applied Science. Full mouth rehabilitation on the patient with maxillary anterior diastema and posterior bite collapse with orthodontic treatment
Why Modern Humans Are Especially Prone to Bite Collapse
From an anthropological perspective, tooth wear is perfectly normal. For most of human history, coarse, unprocessed diets ground teeth down steadily over a lifetime, and the jaw adapted: teeth continued to erupt slightly to compensate for the lost height, dental arches shortened as teeth migrated forward, and the jaw joint remodeled.21PubMed Central. Tooth wear: the view of the anthropologist In those populations, a collapsed bite in the way we think of it today was relatively rare because the whole system adjusted together.
Modern life has flipped the script. Our soft, processed diet produces far less abrasive wear, so enamel lasts longer. But we also live much longer. Life expectancy in prehistoric populations has been estimated at roughly 18 to 25 years, remaining around 30 to 35 years through the Middle Ages and only climbing to around 40 to 45 years in the 19th century before jumping to about 80 years in today’s industrialized countries.22PLOS ONE. The Evolutionary Paradox of Tooth Wear: Simply Destruction or Inevitable Adaptation? Our teeth now need to function for decades longer than they were historically “designed” for, but without the slow, uniform abrasive wear that triggered compensatory eruption and jaw remodeling. Instead, the wear we get today tends to come in concentrated, pathological bursts: acid erosion from modern beverages, nighttime grinding amplified by stress, or sudden loss of posterior support from extractions. The body’s ancient compensatory mechanisms simply are not triggered the same way by these newer patterns of damage, so the bite collapses rather than gracefully adapting.
This evolutionary mismatch helps explain why collapsed bites are overwhelmingly a problem of modern dentistry. It also underscores why prevention matters so much. Wearing a nightguard if you grind, treating acid reflux, limiting highly acidic food and drink, and replacing missing back teeth promptly are all ways to keep the vertical dimension from eroding in the first place. Rebuilding a collapsed bite is possible and outcomes are generally good, but preventing the collapse is always simpler, cheaper, and better for your teeth in the long run.