Lec. 17 Dr. Ali H. Murad

MASTICATORY MUCOSA (keratinized mucosa) This type of mucosa covers the gingiva & the hard . They have similarities in thickness & keratinization of epithelium (in thickness, density, firmness, & being immovably attached). However, there are differences in their submucosa. The mucosa is tightly fixed to the underlying periosteum & immovable. It is pink in color. The lamina properia, is a layer of dense connective tissue, is thicker in the anterior than in the posterior parts of the palate. According to the structures of submucosa the hard palate divided into 4 regions: 1- gingival region adjacent to the teeth. 2- , extending from the posteriorly. 3- Anterio-lateral area (fatty zone) between the raphe & gingiva 4- posterio-lateral area (glandular zone) between the raphe & gingiva. Palatine rugae, appear irregular & often asymmetric, are ridges of extending laterally from the incisive papilla & the anterior part of the palatine raphe Incisive papilla, appear as a thickening of mucosa from the area between the 2 central incisors & extend posteriorly to the palatine raphe.

1

Gingiva: the gingiva extends from the dento-gingival junction to the alveolar mucosa. The epithelium most often parakeratinized with dense underlying lamina propria. The gingiva is limited on the outer surface by muco-gingival junction, which separates it from the alveolar mucosa. The gingiva is divided into: A- free gingiva B- attached gingiva C- Free gingival groove, divide between the free gingiva & the attached gingiva The gingiva is characterized by a surface that appears stippled (because of behavior epithelial ridges) The disappearance of is an indication of inflammation

2

Interdental papilla, is that part of the gingiva that fills the space between 2 adjacent teeth. The gingiva is normally pink but sometimes have a grayish tint. The color depends on the thickness of keratin & on pigmentation. The presence of melanin pigment in the epithelium may give it a brown to black coloration.

The gingiva contains dense fibers of collagen, which divided into the following major groups: • - Cementogingival, extends from the cervical into the lamina propria of the gingiva • - Alveologingival, the fibers arise from the alveolar crest & extend into lamina propria. • - Dentoperiosteal, these fibers can be followed from the cementum into the periosteum of the alveolar crest. Only occur in vestibular & lingual gingiva • - Circular, a small group of fibers that circle the & interlace with the other fibers

3

• - Longitudinal fibers, extend for long distances within the free gingiva, some possibly for the whole length of the arch • - Transseptal fibers, pass horizontally from the root of one tooth, above the alveolar crest, & inserted to the root of the adjacent tooth • - Semicircular fibers, arise from cementum near the cemento-enamel junction, cross the free marginal gingiva, & insert into a similar position on the opposite side of the tooth. • - Transgingival fibers,. The fibers arise from the cervical cementum & extend into the marginal gingiva of the adjacent tooth, merging with the circular fibers • - Interpapillary fibers, pass through the coronal portion of the interdental gingiva in the buccolingual direction, connecting buccal & lingual papillae • - vertical fibers, arise in alveolar mucosa or attached gingiva & pass coronally towards the marginal gingiva & interdental papillae.

4

Blood supply: The blood supply of the gingiva is derived chiefly from the branches of the alveolar arteries that pass upward through the interdental septa. The interdental alveolar arteries perforate the alveolar crest in the interdental space & end in the interdental papilla, supplying it & the adjacent areas of the buccal & lingual gingiva. Also branches from the lingual, mental, & palatine arteries.

5