​1. Soft Tissue

X-rays are blind to soft tissues. Ultrasound can see:

• Gums

• Periodontal tissues

• Oral mucosa

• Soft-tissue masses

• Swellings

• Fibromas

• Cysts

• Lipomas

• Mucocele

2. Infections & Inflammation

X-rays cannot detect early or soft-tissue based infection.

Ultrasound can detect:

• Gingival inflammation

• Abscess formation (before it appears on X-ray)

• Cellulitis

• Early osteomyelitis changes (soft-tissue and periosteum)

• Sinus infection involvement in dental pain

• Lymph node enlargement under the jaw

3. Blood Flow (Doppler Imaging)

X-rays cannot image circulation at all.

Ultrasound can see:

• Blood flow to the gums

• Inflammation-related hyperemia

• Compromised blood supply

• Pulsating lesions

• Vascular malformations

• Venous obstruction

• Arterial anomalies

• Perfusion changes in infected or necrotic tissues

4. Early Disease Can Appear Before Bone Changes

X-rays only show disease after bone destruction has already occurred.

Ultrasound can detect:

• Early periapical inflammation

• Early periodontal disease

• Early abscess (fluid before bone change)

• Pulp vitality changes (via Doppler flow)

• Soft-tissue infection spreading before bone involvement

5. Conditions Hidden Behind Dense Structures

X-rays struggle with overlapping anatomy.

Ultrasound can visualize:

• Buccal/lingual abscess when overlapped by bone

• Impacted tooth soft-tissue involvement

• Gingival hyperplasia

• Soft palate lesions

• Floor-of-mouth masses

• Salivary gland lesions

6. Salivary Glands & Ducts

X-rays cannot visualize glands or ducts.

Ultrasound can see:

• Parotid gland

• Submandibular gland

• Sublingual gland

• Sialoliths (salivary stones)

• Duct obstruction

• Inflammation

7. TMJ (Temporomandibular Joint) Soft Tissues

X-rays cannot show motion or soft tissue of the TMJ.

Ultrasound can visualize:

• Joint effusion

• Disc position (in many cases)

• Ligaments

• Inflammation

• Joint space narrowing dynamically

• Synovial changes

8. Muscles of Mastication

X-rays cannot image muscle.

Ultrasound can examine:

• Masseter muscle

• Temporalis muscle

• Pterygoids

• Muscle tears

• Myofascial pain areas

• Muscle hypertrophy or atrophy

9. Nerves

X-rays cannot visualize nerves.

Ultrasound can identify:

• Inferior alveolar nerve

• Mental nerve

• Lingual nerve

• Nerve impingement or swelling

• Neuromas

• Post-surgical nerve healing

10. Dental Implant Soft-Tissue Integration

X-rays cannot see:

• soft-tissue integration

• inflammation

• peri-implant soft tissue disease

Ultrasound can evaluate:

• peri-implant mucositis

• tissue thickness

• Doppler flow around implants

• early peri-implantitis (soft-tissue stage)

 

X-rays alone miss all soft-tissue, vascular, and early-stage disease.​ Ultrasound may fill that gap.