Oral Cavity Hard and Soft Tissues

• Study notes on hard and soft tissues in the oral cavity, including dental nomenclature

Oral Cavity Tissues

• Enamel, dentin (crown and root), cementum, and supporting bone are hard tissues; all others are soft

Oral Mucosa

• Masticatory mucosa: keratinized/parakeratinized stratified squamous epithelium found on the gingiva and hard palate with long, numerous rete pegs
• Lining mucosa: non-keratinized epithelium on lips, cheeks, alveolar mucosa, floor of mouth, ventral tongue, and soft palate, featuring fewer, shorter, broader rete pegs for movement
• Specialized mucosa: associated with taste sensation on the tongue's dorsum

Palate

• Hard palate: anterior roof of the mouth comprised of palatine processes of the maxillae bones exhibiting rugae (irregular folds) on its anterior surface
• The hard palate has fatty, glandular, and anterior zones
• Soft palate: flexible, posterior portion of the oral cavity roof involved in the gag reflex
• Gingiva: mucous membrane surrounding the tooth, providing a barrier against oral microorganisms
• Free gingiva surrounds the tooth without direct attachment
• Attached gingiva extends from the gingival margin to the alveolar mucosa, bound to periosteum/bone
• Interdental gingiva is determined by tooth contact, surface width, and cementoenamel junction course

Frenum

• Tissue fold attachments connecting parts:
• Labial Frenum: attaches the lip to gums in the anterior oral cavity
• Lingual Frenum: attaches the underside of the tongue to the floor of the mouth
• Buccal Frenum: attaches the cheek side to the oral cavity near the maxillary 1st molar area

Oris

• Superior Oris: upper lip
• Inferior Oris: lower lip
• Commissure: corners of the mouth
• Vermillion: pink-red lip tissue meeting facial skin
• Philtrum: median groove on the upper lip's external surface

Tonsils

• Aggregates of lymphatic nodules in the oral and nasal cavities:
• Palatine tonsils: located at the entrance to the oropharynx
• Tubal tonsils: located on the nasopharynx's lateral walls, posterior to the auditory tube
• Pharyngeal (adenoid) tonsils: located at the roof of the nasopharynx
• Lingual tonsils: located at the base of the tongue

Tongue

• Consists of lingual muscles (extrinsic and intrinsic)
• Four types of papillae are located on the tongue's dorsum
• Circumvallate: large, 10-12 in number, have taste buds
• Foliate: leaf-like ridges with taste buds present on margins near the sulcus terminalis
• Filiform: conical, most numerous, no taste buds, arranged parallel to the sulcus terminalis
• Fungiform: mushroom shaped, have taste buds

Salivary Glands

• Important for saliva production

Teeth Numbering

• Universal numbering system: permanent teeth are numbered 1-32 sequentially, starting with the maxillary right third molar
• Kids have 20 deciduous teeth total, 10 total in each jaw, 5 on each side. Medial incisor, lateral incisor, canine, first and second molar
• Deciduous teeth replaced by 32 permanent teeth total, 16 total in each jaw, 8 on each side
• Medial incisor, lateral incisor, canine, first and second premolar, first to third molar

Enamel

• Hard, thin, translucent acellular layer covering the crown. It consists of 98% inorganic material (calcium hydroxyapatite)
• Clinical crown is enamel exposed above gum line
• Anatomical crown is all of the tooth covered by enamel
• Influenced by salivary glands secretions. which promotes remineralization, decreases demineralization
• Fluoride lowers enamel's critical pH, increasing acid demineralization resistance
• Consists of enamel rods made by ameloblasts; the main protein is amelogenin

Dentin

• Most abundant dental tissue lies deep to the enamel
• tubular structure composed of 60-65% inorganic content and 30-35% organic material,
• Made by neural crest-derived odontoblasts of adjacent mesenchyme

Pulp

• Deep to the dentin, contains nerves, blood vessels, and connective tissues
• Pulp chamber: an open area in the crown of the tooth
• Pulp canal: A small canal in the root of the tooth

Root

• Functions to anchor the tooth
• Clinical Root: covered by gingival tissue
• Anatomical Root: covered by cementum
• Apex: area at the end of the root

Cementum

• Thin, pale-yellowish bone-like tissue covering the root dentin
• More permeable than dentin, removable via abrasion if the root surface is exposed
• Cementoenamel Junction (CEJ) is where enamel and cementum meet

Supporting Tissues

• Alveolar Process: extension of maxilla and mandible supporting teeth.
• Alveolar bone proper (lamina dura): lines the alveolar bone, supporting tooth during the function
• Periodontal ligament: connects cementum and alveolar bone with Sharpey's fibers; organized into fiber groups
• Order of tooth root layers: cementum -- periodontal ligament -- lamina dura

Dental Radiographs

• Detect bone presence/loss, caries, calculus, periodontal conditions
• Do not show hard/soft tissue relations
• Compliment diagnosis
• Radiographic changes lag/show damaged
• Radiopaque (light) structures strongly absorb x-rays (bone, metals)
• Radiolucent (dark) structures poorly absorb x-rays (pulp, periodontal ligament space, caries)

Dental Caries

• Multifactorial disease involves oral flora and dietary carbohydrates.
• Biofilms are resistant to antimicrobials.
• Pellicle formation:
• Proteins cover teeth, slowing diffusion.
• Enables microbial colonization.
• Plaque biofilm builds on pellicle
• Attachment and colonization
• Growth and proliferation
• Maturation and detachment
• Gram (+) cocci (Streptococci) are early colonizers
• Dietary sugars become diffused to the biofilm that produce bacteria and acids that lead to demineralization
• S. Mutans causes general caries that proliferate to make more acid, leading to demineralization
• Small sub-surface lesions can be reversed via remineralization
• Caries appear radiolucent on radiograph showing Widening of periodontal ligament or periapical lucency

Periodontal and Pulpal Tissues

Periodontal and Pulpal Infections

• Periodontal: pathology caused by dental plaque, leads to dental attachment loss and osteolysis
  • Plaque colonization of gingival sulcus
  • Periodontitis: chronic inflammation, destruction of attachment/bone, periodontal pockets form
  • IPDs (Inflammatory Periodontal Diseases): infections due to bacteria in dentogingival junction/subgingival space

Gingivitis

• Microbial composition of subgingival flora changes
  • Plaque thickens with suspended brushing leading to anaerobic gram (-) motile subgingival morphology
  • Reversible condition
  • Polymorphonuclear leukocytes (neutrophils) are Predominate inflammatory cells
  • Determined by: duration, quantity, and microbial composition of plaque as well as immune response

Chronic Periodontitis

• Develops from untreated plaque-induced gingivitis
• Irreversible condition
  • Loss of tooth attachment and loss of bone.
  • Color, texture alterations of marginal gingiva
  • Bleeding on probing, root furcation exposure
  • Tooth morbidity.
  • Exfoliation of teeth
  • Can usually rule out bleeding disorders

Pulpal

• Caused by infection/irritation of pulp, leads to necrosis of pulp

  • Root canal

• Tubular architecture of dentinal tubules provides a pathway for pulpal infection

• Pulpitis is inflammation of the pulp

• Reversible Pulpitis means it's irritated but not infected by bacteria

  • Positive response to EPT (electric pulp tester) and cold test

• Irreversible: Pulp is infected that leads to pulp necrosis and must be treated w/ root canals

• Symptomatic: causes intermittent or spontaneous pain and will continue even after stimuli are gone

  • Asymptomatic irreversible pulpitis: deep carries may not produce

Pulp Necrosis

• Death of the nerves happens due to bacterial sequelae, trauma, and mechanical / chemical irritation
  • Often the end result of trauma, caries, or irreversible pulpitis
  • Treat with a root canal
• Periapical*: around the apex of the tooth
  • Normal Apical Tissue is asymptomatic tooth has no pain to percussion

Type of Apical Peridontitis

Dental Abscess

• A buildup of pus forms inside or around the teeth or gums, caused by a bacterial infection Gingival Abscess: closest to the "neck" of the tooth, or from food impaction Periodontal Abscess is from degtree of the bone loss, or can be by the food that leads to that Periapical Abscess: represents the spread infection from any cause
• Diagnosis Ovoid elevation in tissues/ along the side of the rooth Management with acute lesion
  • Diagnosis with extraay as is done, root canal trearment or antibiotics.

Chronic Abscess has a Sinus tract is present with an infected Tooth

Periodontal Abscess

• Bacterial infection leading to inflammation, bacteria, which leads to a faster destruction

• What are the factors of periodontal Factors

1.) Weakened Immune system 2.) Poor dental dental hygiene 3.) Or closure of a deep periodontal