Views: 0 Author: Site Editor Publish Time: 2025-07-03 Origin: Site
A Closer Look at a Rare but Notable Clinical Concern
Dental impression trays are essential tools in restorative and prosthodontic dentistry. While their use is generally considered safe and non-invasive, occasional patient discomfort may arise during impression procedures — including, in rare instances, the formation of a hematoma. This article explores whether dental impression trays can cause hematomas, what the underlying mechanisms might be, and how clinicians can prevent such occurrences.
What Is a Hematoma?
A hematoma is a localized collection of blood outside the blood vessels, usually caused by trauma that damages capillaries or veins. In the oral cavity, hematomas may appear as bluish or purplish swellings, often tender to touch, and may take days to weeks to resolve.
In dentistry, hematomas are more commonly associated with injections (e.g., inferior alveolar nerve blocks), surgical trauma, or accidental soft tissue injury. However, impression-taking — though seemingly benign — can, under certain conditions, lead to similar outcomes.
How Could an Impression Tray Cause a Hematoma?
While not common, there are several mechanical and anatomical factors through which an impression tray might contribute to soft tissue trauma and subsequent hematoma formation:
1. Oversized or Poorly Fitting Trays
An impression tray that is too large or lacks proper anatomical adaptation can exert excessive pressure on the mucosa, particularly in high-risk areas such as:
• The palatal vault
• The buccal vestibule
• The retromolar pad area
This pressure can compress or even rupture superficial blood vessels.
2. Rigid Tray Material with Sharp Edges
Low-quality or poorly finished trays — especially reusable plastic or metal trays with rough or sharp edges — can nick soft tissue, especially in thin-mucosa patients (e.g., elderly, anticoagulated individuals).
3. Forceful Insertion or Removal
If the tray is inserted or removed too quickly, it may shear against the mucosal surfaces, particularly in areas where soft tissue is thin and vascularized. Hematomas may result from torn vessels in these regions.
4. Underlying Medical Conditions or Medications
Patients taking anticoagulants (e.g., warfarin, DOACs), or those with clotting disorders, are more susceptible to hematomas even with minor trauma. In such cases, even moderate tray pressure could precipitate bleeding.
Case Reports and Evidence
While formal case reports of hematomas caused directly by impression trays are rare in literature, anecdotal reports do exist. For example:
• Patients reporting soreness and bluish swelling after alginate impressions.
• Clinicians noticing mucosal bleeding in patients with fragile tissue or poor tray adaptation.
A 2012 clinical review on "Soft Tissue Complications in Prosthodontics" mentioned iatrogenic hematomas during impression procedures in elderly edentulous patients, suggesting that impression tray pressure was likely contributory.
Preventive Measures for Clinicians
Though uncommon, the potential for hematoma warrants proactive clinical caution, especially in medically compromised patients:
Tray Selection
• Use well-fitted trays with rounded, smooth edges
• For sensitive patients, consider custom trays that minimize excess pressure
Gentle Technique
• Avoid excessive force during insertion and removal
• Educate the patient to avoid biting down forcefully unless instructed
Tissue Protection
• Apply tray adhesive carefully to avoid overflow that may bond to soft tissue
• Use wax padding or tray liners for added comfort
Patient Assessment
• Always inquire about bleeding disorders, anticoagulant use, and previous hematoma history
Final Thoughts
While dental impression trays are generally safe, under specific conditions they can contribute to soft tissue trauma and, rarely, hematoma formation. Clinicians should remain vigilant — particularly with medically vulnerable patients — and adopt careful tray selection and insertion techniques.
Awareness and preventive strategy are key. As with many complications in dentistry, prevention is far easier than management.
Author’s Note: If you or your patient experience unusual swelling, pain, or bruising following an impression procedure, always consider further evaluation. While hematomas often resolve on their own, persistent or expanding lesions may require medical attention.
