NORMAL PERIODONTIUM
-functional system of tissues that sorrounds the teeth and attaches them to jaw bone
-Peri means around; odontous means tooth
-The normal periodontium provides the support necessary to maintain teeth in function. It consists of four principal components:
gingiva, periodontal ligament, cementum, and alveolar bone. Each of these periodontal components is distinct in its location,
tissue architecture, biochemical composition, and chemical composition, but all of these components function together as a single
unit.
GINGIVA
- the part of the oral mucosa that covers the alveolar processes of the jaws and surrounds the necks of the teeth.
-Macroscopic or clinical features: The gingiva is divided anatomically into marginal, attached, and interdental areas
A. Marginal or Free or Unattached Gingiva
-the marginal, or unattached, gingiva is the terminal edge or border of the gingiva
surrounding the teeth in collarlike fashion
-it forms the soft-tissue wall of the gingival sulcus.
-not attached to underlying periodontium of alveolar bone.
B. Interdental Gingiva
-occupies the gingival embrasure, which is the interproximal space beneath the area
of tooth contact.
-The interdental gingiva can be pyramidal or can have a “col” shape conforms to the
shape of the interproximal contact.
-If a diastema is present, the gingiva is firmly bound over the interdental bone and
forms a smooth, rounded surface without interdental papillae
C. Attached Gingiva
-it is firm, resilient, and tightly bound to the underlying periosteum of alveolar bone.
-The facial aspect of the attached gingiva extends to the relatively loose and movable
alveolar mucosa and is demarcated by the mucogingival junction.
-width of the attached gingiva is the distance between the mucogingival junction and the projection on the external surface of the
bottom of the gingival sulcus or the periodontal pocket. Incisors are 3.5-4.5 mm in maxilla, 3.3-3.9 mm in mandible. 1.9 mm in
maxillary and 1.8 mm in mandibular first premolars. The width of the attached gingiva increases with age and in supraerupted
teeth.
Significance:
1. Support to marginal gingiva
2. Provides base for movable alveolar mucosa for action of lips, tongue and cheeks.
3. Withstand forces of mastication and mechanical like toothbrush
4. Barrier for passage of inflammation
5. Resistance to tensional stress
-Microscopic features:
Gingival Epithelium is consists of:
A. Oral Epithelium or Outer Epithelium
-covers the crest and outer surface of the marginal gingiva and the surface of the attached gingiva.
-keratinized squamous epithelium
-stratum basale (basal layer) - cylindric or cuboidal cell ; adjacent to connected tissues; separated by basement
membrane; germitive or able to divide.
-stratum spinosum (prickle cell layer) - prickly in which large polyhedral cells with cytoplasmic process
-stratum granulosum (granular layer) - flattened in plane parallel to gingival surface
-stratum corneum (cornified layer) - closely pack flattened cells with no nuclei, organelles as they become keratinized.
B. Sulcular Epithelium
-lines the gingival sulcus
-It is a thin, nonkeratinized stratified squamous epithelium without rete pegs, and it extends from the coronal limit of the
junctional epithelium to the crest of the gingival margin.
C. Junctional Epithelium
-consists of a collarlike band of stratified squamous nonkeratinizing epithelium.
, -Blood Supply:
A. Supraperiosteal Arterioles
-mainly supply Free gingiva and Gingival Sulcus
-these arterioles are terminal brances of sublingual, mental, buccal, facial, greater palatine, infraorbital and posterior superior
dental arteries.
B. Vessels of Periodontal Ligament
-mainly supply Col area.
-Col is body-like depression in interproximal spaces.
C. Arterioles emerging from crest of interdental septa
-mainly supply attached gingiva.
CRITERIA OF NORMAL GINGIVA
Color - coral pink
Surface texture - smooth on marginal gingiva; stippled attached gingiva.
Contour - marginal gingiva follows a scalloped outline; straight line along teeth with relative flat surface.
Shape - shape of interdental gingiva depends on contour of proximal tooth surface, location and shape of proximal contact and
dimensions of gingival embrasures.
Size - corresponds to the sum total of bulk of cellular and intercellular elements and their vascular supply.
Consistency - on palpation with blunt instrument, attached gingiva should be firm, resilient and tightly bound to the underlying
hard tissues.
PERIODONTAL LIGAMENT
-soft, specialized connective tissue situated between cementum covering root of the tooth and bone forming the socket wall.
-width - 0.15-0.38mm
-shape - hourglass apicocoronally
- thinnest at the axis of rotation in the middle and widens coronally and apically.
-synonyms: Periodontal membrane, Alveolodental ligament, desmodont, pericementum, dental periosteum and gomphosis.
-Cellular composition:
1. Synthetic cells
- characteristics: should be actively synthesizing ribosomes; increase in the compliment of rough endoplasmic reticulum and golgi
apparatus; large open faced or vesicular nucleus containing prominent nucleoli.
A. Osteoblasts - bone builders; covers periodontal surface of alveolar bone.
B. Fibroblasts- fiber builders; most prominent connective tissue cell; main function is production of various types of fibers and
also instrumental in synthesis of the connective tissue matrix.
C. Cementoblasts - cementum builders
2. Resorptive cells
A. Osteoclasts - resorb the bone and tend to be large and multinucleated
B. Cementoclast - located in the Howship’s la
C. Fibroblasts - capable of synthesis and resorption; contain fragments of collagen that appear to be undergoing digestion.
3. Progenitor cells
4. Other epithelial cells
Epithelial cell rest of Malassez - found close to cementum. First described by Malassez in 1884 are remnants of the epithelium of
Hertwig’s epithelial root sheath.
5. Connective Tissue Cells
A. Mast Cells - are relatively small, round or oval cell having a diameter of almost 12 to 15 um.
B. Macrophages - may also be present in the ligament. They are capable of phagocytosis.
-Periodontal Ligament Fibers:
Transseptal group
Transseptal fibers extend interproximally over the alveolar bone crest and are embedded in the cementum of adjacent teeth. They
are reconstructed even after destruction of the alveolar bone resulting from periodontal disease and they are responsible for
returning teeth to their original state after orthodontic therapy. These fibers may be considered as belonging to the gingiva because
they do not have osseous attachment.
Alveolar crest group
Alveolar crest fibers extend obliquely from the cementum just beneath the junctional epithelium to the alveolar crest. Fibers also
run from the cementum over the alveolar crest and to the fibrous layer of the periosteum covering the alveolar bone. Also prevent
the extrusion of the tooth and resist lateral tooth movements.
Horizontal group
-functional system of tissues that sorrounds the teeth and attaches them to jaw bone
-Peri means around; odontous means tooth
-The normal periodontium provides the support necessary to maintain teeth in function. It consists of four principal components:
gingiva, periodontal ligament, cementum, and alveolar bone. Each of these periodontal components is distinct in its location,
tissue architecture, biochemical composition, and chemical composition, but all of these components function together as a single
unit.
GINGIVA
- the part of the oral mucosa that covers the alveolar processes of the jaws and surrounds the necks of the teeth.
-Macroscopic or clinical features: The gingiva is divided anatomically into marginal, attached, and interdental areas
A. Marginal or Free or Unattached Gingiva
-the marginal, or unattached, gingiva is the terminal edge or border of the gingiva
surrounding the teeth in collarlike fashion
-it forms the soft-tissue wall of the gingival sulcus.
-not attached to underlying periodontium of alveolar bone.
B. Interdental Gingiva
-occupies the gingival embrasure, which is the interproximal space beneath the area
of tooth contact.
-The interdental gingiva can be pyramidal or can have a “col” shape conforms to the
shape of the interproximal contact.
-If a diastema is present, the gingiva is firmly bound over the interdental bone and
forms a smooth, rounded surface without interdental papillae
C. Attached Gingiva
-it is firm, resilient, and tightly bound to the underlying periosteum of alveolar bone.
-The facial aspect of the attached gingiva extends to the relatively loose and movable
alveolar mucosa and is demarcated by the mucogingival junction.
-width of the attached gingiva is the distance between the mucogingival junction and the projection on the external surface of the
bottom of the gingival sulcus or the periodontal pocket. Incisors are 3.5-4.5 mm in maxilla, 3.3-3.9 mm in mandible. 1.9 mm in
maxillary and 1.8 mm in mandibular first premolars. The width of the attached gingiva increases with age and in supraerupted
teeth.
Significance:
1. Support to marginal gingiva
2. Provides base for movable alveolar mucosa for action of lips, tongue and cheeks.
3. Withstand forces of mastication and mechanical like toothbrush
4. Barrier for passage of inflammation
5. Resistance to tensional stress
-Microscopic features:
Gingival Epithelium is consists of:
A. Oral Epithelium or Outer Epithelium
-covers the crest and outer surface of the marginal gingiva and the surface of the attached gingiva.
-keratinized squamous epithelium
-stratum basale (basal layer) - cylindric or cuboidal cell ; adjacent to connected tissues; separated by basement
membrane; germitive or able to divide.
-stratum spinosum (prickle cell layer) - prickly in which large polyhedral cells with cytoplasmic process
-stratum granulosum (granular layer) - flattened in plane parallel to gingival surface
-stratum corneum (cornified layer) - closely pack flattened cells with no nuclei, organelles as they become keratinized.
B. Sulcular Epithelium
-lines the gingival sulcus
-It is a thin, nonkeratinized stratified squamous epithelium without rete pegs, and it extends from the coronal limit of the
junctional epithelium to the crest of the gingival margin.
C. Junctional Epithelium
-consists of a collarlike band of stratified squamous nonkeratinizing epithelium.
, -Blood Supply:
A. Supraperiosteal Arterioles
-mainly supply Free gingiva and Gingival Sulcus
-these arterioles are terminal brances of sublingual, mental, buccal, facial, greater palatine, infraorbital and posterior superior
dental arteries.
B. Vessels of Periodontal Ligament
-mainly supply Col area.
-Col is body-like depression in interproximal spaces.
C. Arterioles emerging from crest of interdental septa
-mainly supply attached gingiva.
CRITERIA OF NORMAL GINGIVA
Color - coral pink
Surface texture - smooth on marginal gingiva; stippled attached gingiva.
Contour - marginal gingiva follows a scalloped outline; straight line along teeth with relative flat surface.
Shape - shape of interdental gingiva depends on contour of proximal tooth surface, location and shape of proximal contact and
dimensions of gingival embrasures.
Size - corresponds to the sum total of bulk of cellular and intercellular elements and their vascular supply.
Consistency - on palpation with blunt instrument, attached gingiva should be firm, resilient and tightly bound to the underlying
hard tissues.
PERIODONTAL LIGAMENT
-soft, specialized connective tissue situated between cementum covering root of the tooth and bone forming the socket wall.
-width - 0.15-0.38mm
-shape - hourglass apicocoronally
- thinnest at the axis of rotation in the middle and widens coronally and apically.
-synonyms: Periodontal membrane, Alveolodental ligament, desmodont, pericementum, dental periosteum and gomphosis.
-Cellular composition:
1. Synthetic cells
- characteristics: should be actively synthesizing ribosomes; increase in the compliment of rough endoplasmic reticulum and golgi
apparatus; large open faced or vesicular nucleus containing prominent nucleoli.
A. Osteoblasts - bone builders; covers periodontal surface of alveolar bone.
B. Fibroblasts- fiber builders; most prominent connective tissue cell; main function is production of various types of fibers and
also instrumental in synthesis of the connective tissue matrix.
C. Cementoblasts - cementum builders
2. Resorptive cells
A. Osteoclasts - resorb the bone and tend to be large and multinucleated
B. Cementoclast - located in the Howship’s la
C. Fibroblasts - capable of synthesis and resorption; contain fragments of collagen that appear to be undergoing digestion.
3. Progenitor cells
4. Other epithelial cells
Epithelial cell rest of Malassez - found close to cementum. First described by Malassez in 1884 are remnants of the epithelium of
Hertwig’s epithelial root sheath.
5. Connective Tissue Cells
A. Mast Cells - are relatively small, round or oval cell having a diameter of almost 12 to 15 um.
B. Macrophages - may also be present in the ligament. They are capable of phagocytosis.
-Periodontal Ligament Fibers:
Transseptal group
Transseptal fibers extend interproximally over the alveolar bone crest and are embedded in the cementum of adjacent teeth. They
are reconstructed even after destruction of the alveolar bone resulting from periodontal disease and they are responsible for
returning teeth to their original state after orthodontic therapy. These fibers may be considered as belonging to the gingiva because
they do not have osseous attachment.
Alveolar crest group
Alveolar crest fibers extend obliquely from the cementum just beneath the junctional epithelium to the alveolar crest. Fibers also
run from the cementum over the alveolar crest and to the fibrous layer of the periosteum covering the alveolar bone. Also prevent
the extrusion of the tooth and resist lateral tooth movements.
Horizontal group
