Alveolar ridge
After dentition is missing, the alveolar process is gradually absorbed to form alveolar ridge. It is the foundation of natural dentition. The mucosa covered by it is highly keratinized squamous epithelium, and the submucosa is closely connected with periosteum, which can bear greater chewing pressure.
Check whether the extraction socket is completely healed. Generally, new dentures can only be repaired after they are completely healed.
The oral cavity is divided into: oral vestibule and oral headquarters.
mucous membrane
? Mucosa is the medium that transmits the tensile force from complete denture to jaw, and improper denture base will inevitably damage oral mucosa. Check for mucosal atrophy or hyperplasia. For patients who have worn old dentures, we should check whether there are any bad dentures that cause alveolar ridge softening, mucosal congestion, dentures, gingival tumors, swelling or ulcers. If there are the above symptoms, the old denture should be modified accordingly. At the same time, patients are advised not to use the old denture as much as possible, and then repair the new denture after the symptoms disappear.
Too soft mucosa is not conducive to denture retention and should be corrected by surgery.
Oral vestibule
Located between the alveolar ridge and the labial and buccal mucosa, it is a potential gap. The submucosa is loose connective tissue, and the labial and buccal base of complete denture is in this area. It should extend as far as possible to the mucosal folds without interfering with the activities of lips and cheeks to ensure the closure of the basal margin.
Labial frenum
Located in the vestibule of the mouth, on the extension line corresponding to the proximal boundary line of the original central incisor, it is a fan-shaped or linear mucosal fold. It is the attachment point between orbicularis oris muscle and mandible. With the movement of labial muscles, there is a large range of activities. The lip base of complete denture should form corresponding notch in this area, so as not to hinder the movement of frenum and affect the retention of denture.
Buccal frenum
Located at the root of bicuspid, attached to the buccal side of alveolar ridge, in a fan shape. This is a mucosal fold similar to labial frenum's. There are buccal frenulums on the left and right sides of the maxilla and mandible, and the synchronization is less than that of labial frenum.
Anterior arch area: The area between labial frenum and buccal frenum is the anterior arch area.
Posterior arch area: The posterior arch area is behind the buccal frenum.
Zygomatic process
The bony process in the posterior arch area is equivalent to the root of the left and right maxillary first molars. The mucous membrane covered in this area is thin, and the edge of the corresponding base should be padded, otherwise it will cause tenderness or instability of the denture.
Maxillary tubercle
It is a round bony process located at the distal ends of both sides of maxillary alveolar ridge, and its surface is covered with mucosa. There is obvious inversion on the buccal side, forming a buccal space with the buccal mucosa. This area is of great significance to the retention of maxillary complete denture, and the buccal edge of maxillary denture should fill this gap.
Buccal marginal area
Located in the posterior mandibular arch, the anterior boundary is mandibular buccal ligament, and the posterior boundary is in front of the anterior edge of inferior masseter muscle. When the alveolar ridge at the back of mandible is flat, this area is also called buccal fossa area. This area is large in area and dense in bone. The denture base can be stretched in a large range in this area and can withstand greater pressure. Play a role in supporting and stabilizing dentures.
If the denture edge exceeds the external oblique ridge, the denture base will be wider than the buccal muscle attachment part and located on the buccal muscle fiber. In the buccal shed area, the buccal muscle fibers are in close contact with the bones, and the buccal muscle fibers are very thin and difficult to move. In addition, the muscle bundle under the buccal muscle is not tense, and it is a relaxed area outside the external oblique ridge. Muscle fibers move back and forth, parallel to the edge of denture, and act in the horizontal direction. When chewing, the force to dislocate the denture is very small, so the edge of the denture can extend to this area.
If the denture edge is not stretched enough in this area, it is difficult to form the correct convex shape of the buccal side edge, which leads to the accumulation of food under the buccal groove and denture base.
? Distal buccal horn region
It is located in the posterior mandibular arch area, in front of the masseter muscle and behind the buccal margin area.
Limited by the movement of the masseter front, the edge of the denture base corresponding to this area cannot be stretched too much. When the masseter muscle moves, it will loosen the denture.