Mandible vs. Maxilla: Differences and Functions Explained

When discussing the human skull, two important bones that often come up are the mandible and maxilla. These two bones are crucial for various functions, including chewing, speaking, and breathing. While they are both part of the facial structure, they serve different roles and have distinct features. As a professional dentist in Oklahoma City, OK, it’s important to understand these bones and their functions to help in diagnosing and treating various dental and oral health issues. Today, we want to share this information to help you learn! 

What is the Mandible?

The mandible is the lower jawbone, the largest and strongest bone in the face. It is a U-shaped structure that holds the lower teeth and forms the lower part of the face. The mandible is unique because it is the only movable bone in the skull, allowing us to open and close our mouths for functions like chewing, speaking, and breathing. This mobility is thanks to the temporomandibular joint (TMJ), which connects the mandible to the skull.

The mandible consists of several key parts:

• Body: The horizontal portion of the mandible that holds the teeth.
• Rami: The two vertical extensions that connect the body of the mandible to the skull.
• Angle: The area where the body and rami meet.
• Mental Foramen: Small holes in the mandible through which nerves and blood vessels pass.

What is the Maxilla?

The maxilla refers to the upper jawbone, which plays a vital role in the structure of the face. Unlike the mandible, the maxilla is fixed and does not move. The maxilla forms the upper part of the mouth, the floors of the orbits (eye sockets), and a portion of the nasal cavity. It also holds the upper teeth and connects with other facial bones like the zygomatic bones (cheekbones), nasal bones, and palatine bones (roof of the mouth).

The maxilla is made up of:

• Maxillary Body: The central portion of the maxilla.
• Palatine Process: The portion of the maxilla that forms the roof of the mouth.
• Zygomatic Process: The extension that connects with the cheekbones.
• Alveolar Ridge: The part of the maxilla that holds the upper teeth.

Mandible vs. Maxilla: Key Differences

While both the mandible and maxilla are essential components of the facial skeleton, there are several significant differences between the two:

1. Location and Mobility:
   • The mandible is the lower jawbone, and it is the only movable bone in the skull. This allows us to move our jaw for various functions like eating, speaking, and yawning.
     
     
   • The maxilla, on the other hand, is the upper jawbone and is fixed in place. It plays a static role in holding the upper teeth and forming the structure of the face.
2. Function:
   • The mandible supports the lower set of teeth and facilitates chewing by allowing the jaw to move up and down and side to side.
   • The maxilla holds the upper teeth and helps form the roof of the mouth, which is essential for proper speech and swallowing. It also supports the nose and the orbits of the eyes.
3. Shape and Structure:
   • The mandible is U-shaped, making it strong and sturdy for its role in chewing and speaking.
   • The maxilla is rectangular and is composed of several different sections that connect to other facial bones. It is also less dense than the mandible.
4. Teeth Support:
   • The mandible holds the lower teeth, which are involved in biting and grinding food.
   • The maxilla supports the upper teeth, which align with the lower teeth during biting and chewing.
5. Size and Strength:
   • The mandible is the largest and strongest bone in the face, necessary for the powerful actions of chewing and speaking.
   • The maxilla is not as strong or as large as the mandible, but it still plays a critical role in the face’s overall structure.
6. Bone Connection:
   • The mandible is connected to the skull by the temporomandibular joint (TMJ), allowing it to move.
   • The maxilla is connected to the rest of the skull and is fixed in place, with no direct mobility.

The Functions of the Mandible and Maxilla

Both the maxilla and mandible have important roles that contribute to overall oral health and facial structure. Below are some of the functions these bones perform:

1. Chewing and Digestion:

The mandible and maxilla work together to help us chew food. The lower teeth in the mandible and the upper teeth in the maxilla come together during chewing, breaking food down into smaller pieces. The movement of the mandible helps grind the food and mix it with saliva to aid in digestion.

2. Speaking:

The proper alignment of the mandible and maxilla is crucial for clear speech. The tongue, teeth, and lips all work in harmony to form sounds. A misalignment between the mandible and maxilla can lead to speech disorders, such as a lisp or difficulty pronouncing certain words.

3. Breathing:

The maxilla is involved in the structure of the nasal passages. A properly aligned maxilla allows for optimal airflow through the nose, which is essential for effective breathing. The mandible, being part of the lower jaw, also plays a role in supporting the airway.

4. Facial Appearance:

The maxilla and mandible both contribute to the shape and structure of the face. A well-developed mandible gives the lower face strength and definition, while the maxilla helps form the mid-face, including the cheekbones and the upper lip.

Common Issues Related to the Mandible and Maxilla

Several dental and medical conditions can arise from problems with the mandible and maxilla:

1. Malocclusion: Malocclusion refers to an improper bite, where the teeth in the upper and lower jaws don’t align properly. This can occur due to issues with either the mandible or maxilla and may result in difficulty chewing, jaw pain, or speech problems.
2. TMJ Disorders: The temporomandibular joint (TMJ) connects the mandible to the skull. Disorders in this joint can lead to pain, clicking sounds, and restricted jaw movement. TMJ disorders can be caused by trauma, arthritis, or misalignment of the mandible.
3. Cleft Lip and Palate: A cleft lip or palate occurs when the maxilla does not fuse properly during fetal development, leading to a gap in the upper lip or palate. This condition requires surgical intervention to correct and can affect speech and feeding.
4. Jaw Fractures: The mandible is susceptible to fractures due to its mobility. Trauma to the jaw, such as a car accident or sports injury, can cause a break in the mandible. Treatment may involve realigning the bone and securing it with plates or screws.

If you’re experiencing any of these issues, Reflections Dental Care is here to help. Contact us today to schedule a consultation!

Dental Implants and Bone Structure

Dental implants are a popular and effective solution for replacing missing teeth, and both the mandible and maxilla play a crucial role in the success of this procedure. Implants are typically placed in the alveolar ridge of the mandible or maxilla, where the natural teeth once were. The procedure involves inserting a titanium post into the bone, which then fuses with the bone through a process called osseointegration.

The quality and density of the bone in both the mandible and maxilla are critical for successful implant placement. Since the mandible is denser and stronger than the maxilla, implants in the lower jaw typically have a higher success rate. However, both bones can support dental implants effectively, given they are in good health and have sufficient bone volume. If a patient’s bone density is insufficient, bone grafts may be required to enhance the implant’s success.

If you’re considering dental implants in Oklahoma City, OK, our team is here to help. Call us today at (405) 751-4556 for a consultation and learn how we can restore your smile!