Temporomandibular joint and salivary glands overview: Dental assisting

The temporomandibular joint or TMJ and the salivary glands work together to support essential functions such as chewing, speaking, swallowing, and maintaining oral health.

As a dental assistant, your knowledge of how these structures function is crucial as you assist the dental team with addressing disorders related to TMJ and salivary gland function.

Now, the TMJ is a bilateral joint, meaning there's a TMJ on each side of the head. It's formed by the mandible, commonly called the lower jaw, and the temporal bone, which makes up the lower side of the head.

The TMJ is made up of three bony parts an oval depression in the temporal bone called the glenoid fossa, a raised part of the temporal bone called the articular eminence, and a protrusion on the mandible called the condyloid process.

Surrounding the TMJ is a fibrous joint capsule called the capsular ligament, which provides stability and support for the joint.

The articular space is the space between the mandibular condyle and the glenoid fossa within the joint capsule. Within this space, the articular disc or meniscus provides a cushion of dense fibrous connective tissue that separates the articular space into upper and lower compartments.

These compartments are filled with synovial fluid which lubricates the joint during movement. The muscles of mastication are the muscles used to chew.

These muscles work with other smaller accessory muscles to allow the TMJ to move the mandible in several different movements.

A hinge action involves opening and closing, while a gliding movement is a forward movement called protrusion and a backward motion called retrusion.

Lateral movement allows a side to side grinding movement. These combined movements allow for essential functions like speech, chewing, swallowing, and overall oral function.

Now some of the patients you care for may experience a temporal mandibular disorder or TMD for short, that can affect one or both TMJs.

Causes stem from a variety of factors including injury to the head, jaw, and neck, stress, genetics, systemic disorders like arthritis, and maocclusion, which is when the upper and lower teeth come together abnormally.

They can even be caused by habits like Bruxism, commonly known as teeth grinding and clenching or tightly holding the teeth together.

TMD symptoms can take many forms including aalgia or ear pain, spasms in the face, head, or neck, headaches, and pain while chewing.

In some cases, a popping, clicking, or cracking sound called crepitus can be heard in the joint during movement. There can also be trismus or spasms of the muscles of mastication.

This can cause pain and difficulty when chewing and limited mandibular movement when yawning or trying to open the mouth wide.

When this occurs, patients may say their jaw locks or gets stuck. Now let's switch gears and look at the salivary glands.

There are 3 major paired salivary glands, including the parotid, submandibular, and sublingual glands. These 3 major salivary glands, together with numerous minor salivary glands, deposit saliva into the oral cavity through small tubes called salivary ducts.

Saliva plays a key role in oral health, and there are two types serous and mucus. Mucous saliva is thicker and contains mucin, while serous saliva is watery and rich in enzymes like amylase.

Saliva lubricates the mouth and moistens food to make it easier to swallow, and it contains the enzyme amylase that breaks down starches in food, which starts the process of digestion.

Saliva also helps reduce the risk of tooth decay and gum disease by washing away accumulated food debris and balancing the pH in the mouth.

Also, through the process of remineralization, saliva replaces the minerals that are stripped away from the teeth by acids produced by bacteria as they metabolize dietary sugars in a process called demineralization.

Sometimes problems can arise if a buildup of minerals like calcium hardens and forms a stone within one of the salivary ducts called a salolith.

This can obstruct the flow of saliva, preventing it from entering the mouth, resulting in pain and swelling. With less saliva, patients are at increased risk of tooth decay and may have trouble swallowing, since there is less saliva to moisten the food.

When this occurs, surgical removal of the stone might be needed. Now let's look at how the functions of the TMJ and salivary glands relate to your role as a dental assistant.

During routine dental visits, you may encounter patients who tell you they feel pain or notice a popping sound when they move their jaw, or they may tell you that they feel like their jaw gets stuck when they try to open their mouths.

Other times a patient might tell you that they feel some swelling inside their cheek or have a dry mouth, which makes it difficult to eat foods like popcorn and crackers.

Your understanding of the TMJ and salivary gland function will prompt you to recognize these as symptoms that need further exploration by the dentist and to document the information in the dental record.

All right, as a quick recap, the TMJ and salivary glands work together to support essential functions like chewing, speaking, swallowing, and maintaining oral health.

As a dental assistant, your understanding of TMJ and salivary gland functions helps you to recognize symptoms in patients during routine dental visits and is crucial as you assist the dental team with addressing disorders related to TMJ and salivary gland function.