Alveolar process/dental courses

INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

ALVEOLARALVEOLAR
PROCESSPROCESS

DEFINITIONDEFINITION

 It forms when the tooth erupts to provideIt forms when the tooth erupts to provide
the osseous attachment to the formingthe osseous attachment to the forming
periodontal ligament, it disappearsperiodontal ligament, it disappears
gradually after the tooth is lost.gradually after the tooth is lost.
 The alveolar process is the portion ofThe alveolar process is the portion of
maxilla and mandible that forms andmaxilla and mandible that forms and
support the tooth socketsupport the tooth socket..

ALVEOLAR PROCESS OF MAXILLAALVEOLAR PROCESS OF MAXILLA

ALVEOLAR PROCESS OFALVEOLAR PROCESS OF
MANDIBLEMANDIBLEwww.indiandentalacademy.com

DEVELOPMENTDEVELOPMENT

 Near the end of the second month of fetalNear the end of the second month of fetal
life the maxilla as well as the mandiblelife the maxilla as well as the mandible
forms a groove that is open towards theforms a groove that is open towards the
surface of oral cavity.surface of oral cavity.
 The tooth germs are contained in thisThe tooth germs are contained in this
groove, which also includes the alveolargroove, which also includes the alveolar
nerves and vessels and gradually septanerves and vessels and gradually septa
develops between the adjacent tooth gems.develops between the adjacent tooth gems.
 An alveolar process develops only duringAn alveolar process develops only during
the eruption of teeth. During the period ofthe eruption of teeth. During the period of
rapid growth chondroid bone is formed.rapid growth chondroid bone is formed.

INTRA-MEMBRANOUS DEVELOPMENTINTRA-MEMBRANOUS DEVELOPMENT
OF ALVEOLAR PROCESSOF ALVEOLAR PROCESS

STRUCTURESTRUCTURE

The alveolar process consist of:-The alveolar process consist of:-
 ALVEOLAR BONE PROPERALVEOLAR BONE PROPER
 SUPPORTING ALVEOLAR BONESUPPORTING ALVEOLAR BONE
((i) Cortical platei) Cortical plate
(ii) Cancellous(ii) Cancellous bonebone

ALVEOLAR BONE PROPERALVEOLAR BONE PROPER
 It consists of thin lamellae of boneIt consists of thin lamellae of bone
that surrounds the root and providethat surrounds the root and provide
attachment to principal fibres ofattachment to principal fibres of
periodontal ligamentperiodontal ligament

Alveolar bone proper composed of compactAlveolar bone proper composed of compact
bonebone

 It contains a series of openingsIt contains a series of openings
through which neurovascularthrough which neurovascular
bundle link the PDL with thebundle link the PDL with the
central component of alveolarcentral component of alveolar
bone, the cancellous bone. So thisbone, the cancellous bone. So this
is also known as CRIBRIFORMis also known as CRIBRIFORM
PLATE.PLATE.

CRIBRIFORM PLATECRIBRIFORM PLATEwww.indiandentalacademy.com

 The layer of bone into which theThe layer of bone into which the
principle fibres are inserted i.e.principle fibres are inserted i.e.
SHARPEY’s FIBRES, isSHARPEY’s FIBRES, is
sometimes called BUNDLEsometimes called BUNDLE
BONE.BONE.

Sharpey’s fiber appear as dark pinkSharpey’s fiber appear as dark pink
streaks within the bundle bonestreaks within the bundle bone

SUPPORTING ALVEOLAR BONESUPPORTING ALVEOLAR BONE
 It surrounds the alveolar bone properIt surrounds the alveolar bone proper
and gives support to the socket.and gives support to the socket.
 It is divided into two parts:-It is divided into two parts:-
1. Cortical plate1. Cortical plate
2. Cancellous bone2. Cancellous bone

CORTICAL PLATECORTICAL PLATE
 It consists of compact bone.It consists of compact bone.
 Forms outer and inner plate of alveolar processForms outer and inner plate of alveolar process
 Plate is thinner in the maxilla than mandible.Plate is thinner in the maxilla than mandible.
 In maxilla outer plate is perforated throughIn maxilla outer plate is perforated through
which blood and lymph vessels pass.which blood and lymph vessels pass.

In mandible it is thickest in the premolarIn mandible it is thickest in the premolar
and molar region esp. on buccal side.and molar region esp. on buccal side.

Histologically, the cortical plate consists of ;-Histologically, the cortical plate consists of ;-
 Longitudinal lamellaeLongitudinal lamellae
 Haversian systemHaversian system

CANCELLOUS BONECANCELLOUS BONE
 It fills the area between the socket and theIt fills the area between the socket and the
compact bone.compact bone.
 It occupies most of the interdental septumIt occupies most of the interdental septum
but only a relatively small portion of buccalbut only a relatively small portion of buccal
and the palatal bone plates.and the palatal bone plates.
 The cancellous bone contains BONEThe cancellous bone contains BONE
TRABECULAE .TRABECULAE .

Cancellous BoneCancellous Bone

Cancellous bone is of two main types:-Cancellous bone is of two main types:-
 TYPE 1TYPE 1
Regular and horizontal inter-radicular lamellae.Regular and horizontal inter-radicular lamellae.
Found more in mandible.Found more in mandible.

TYPE 2TYPE 2
Irregularly arranged inter-radicular lamellae.Irregularly arranged inter-radicular lamellae.
Found more in maxilla.Found more in maxilla.

BONE CELLSBONE CELLS

BONE CELLSBONE CELLS
 Classically three types of bone cells areClassically three types of bone cells are
described:-described:-
1.1. OSTEOBLASTOSTEOBLAST
2.OSTEOCYTES2.OSTEOCYTES
3. OSTEOCLAST3. OSTEOCLAST

OSTEOBLASTOSTEOBLAST
 These are uninucleated cells that synthesizeThese are uninucleated cells that synthesize
organic matrix, OSTEOID.organic matrix, OSTEOID.
 Responsible for mineralization and are derivedResponsible for mineralization and are derived
from multipotent mesenchymal cells,from multipotent mesenchymal cells,
differentiate through a precursor cell, thedifferentiate through a precursor cell, the
PREOSTEOBLAST.PREOSTEOBLAST.
 When bone is no longer forming the surfaceWhen bone is no longer forming the surface
osteoblast become inactive and are termedosteoblast become inactive and are termed
LINING CELLS.LINING CELLS.
 Secretes TYPE 1 and TYPE IV collagen.Secretes TYPE 1 and TYPE IV collagen.www.indiandentalacademy.com

Electron micrograph of anElectron micrograph of an
osteoblastosteoblast

OSTEOCYTEOSTEOCYTE
 Some of the osteoblast entraped in lacunaeSome of the osteoblast entraped in lacunae
and are then called OSTEOCYTES.and are then called OSTEOCYTES.
 The more rapid the bone formation is theThe more rapid the bone formation is the
more number of osteocytes are present permore number of osteocytes are present per
unit volume.unit volume.
 Processes from adjacent osteocytes andProcesses from adjacent osteocytes and
lining cells are joined together forming thelining cells are joined together forming the
osteoblast-osteocyte complex necessary toosteoblast-osteocyte complex necessary to
bone matrix mantainance and vitality.bone matrix mantainance and vitality.

Osteocytes lacune and theirOsteocytes lacune and their
canaliculicanaliculiwww.indiandentalacademy.com

OSTEOCLASTOSTEOCLAST
 These are multi-nucleated large cells.These are multi-nucleated large cells.
 It is formed against bone surfaceIt is formed against bone surface
occupying shallow, hollowed outoccupying shallow, hollowed out
depressions called HOWSHIP’sdepressions called HOWSHIP’s
LACUNAE.LACUNAE.
 It is chacterized cytochemically byIt is chacterized cytochemically by
possessing tartarate resistantacidpossessing tartarate resistantacid
phosphatase within it’s cytoplasmic vesiclesphosphatase within it’s cytoplasmic vesicles
and vacuoles.and vacuoles. www.indiandentalacademy.com

Electron micrograph of osteoclastElectron micrograph of osteoclast

CYTOPLASM OF OSTEOCLAST FILLEDCYTOPLASM OF OSTEOCLAST FILLED
WITH MITOCHONDRIA, LYSOSOMES &WITH MITOCHONDRIA, LYSOSOMES &
RIBOSOMESRIBOSOMESwww.indiandentalacademy.com

CONTENTSCONTENTS

CONTENTSCONTENTS
 Alveolar bone consists of:-Alveolar bone consists of:-
1. INORGANIC MATTER – 65%1. INORGANIC MATTER – 65%
2. ORGANIC MATTER _ 35%2. ORGANIC MATTER _ 35%

INORGANIC MATTERINORGANIC MATTER
 It is composed principally of mineral calciumIt is composed principally of mineral calcium
and phosphate.and phosphate.
 Also includes hydroxyl, carbonate, citrate andAlso includes hydroxyl, carbonate, citrate and
trace amount of sodium, magnesium andtrace amount of sodium, magnesium and
flourine.flourine.
 Mineral salts are in form of HYDROXYMineral salts are in form of HYDROXY
APATITE CRYSTALS.APATITE CRYSTALS.

REGULARLY ARRANGEDREGULARLY ARRANGED
HYDROXYAPATITE CRYSTALSHYDROXYAPATITE CRYSTALSwww.indiandentalacademy.com

ORGANIC MATTERORGANIC MATTER
 It is primarily TYPE 1 COLLAGEN which lies in theIt is primarily TYPE 1 COLLAGEN which lies in the
ground substance of GLYCOPROTEIN ANDground substance of GLYCOPROTEIN AND
PROTEOGLYCAN.PROTEOGLYCAN.
** Collagen 88-89%Collagen 88-89%
* Non collagen 11-12%* Non collagen 11-12%
-Glycoprotein 6.5-10%-Glycoprotein 6.5-10%
-Proteoglycan 0.8%-Proteoglycan 0.8%
-Sialoproteins 0.35%-Sialoproteins 0.35%
-Lipids 0.4%-Lipids 0.4%

COLLAGEN FIBRE ANDCOLLAGEN FIBRE AND
INTERFIBRILLAR SUBSTANCEINTERFIBRILLAR SUBSTANCEwww.indiandentalacademy.com

SOCKET WALLSOCKET WALL
 The socket wall consists of denseThe socket wall consists of dense
lamellated bone, some of which islamellated bone, some of which is
arranged in HAVERSIANarranged in HAVERSIAN
SYSTEM and BUNDLE BONE.SYSTEM and BUNDLE BONE.

INTERDENTAL SEPTUMINTERDENTAL SEPTUM
 It consists of cancellous boneIt consists of cancellous bone
bordered by socket wall andbordered by socket wall and
cribriform plates (lamina dura orcribriform plates (lamina dura or
alveolar bone proper).alveolar bone proper).

Interdental septum between twoInterdental septum between two
adjacent teethadjacent teethwww.indiandentalacademy.com

INTER-RADICULAR SEPTUMINTER-RADICULAR SEPTUM
(Low power)(Low power)

Inter-radicular septumInter-radicular septum
(High power)(High power)

BLOOD SUPLYBLOOD SUPLY

 The DENTAL ARTERY which is a branch ofThe DENTAL ARTERY which is a branch of
the SUPERIOR OR INFERIOR ALVEOLARthe SUPERIOR OR INFERIOR ALVEOLAR
ARTERY, dismisses the intra-septal arteryARTERY, dismisses the intra-septal artery
before it enters the tooth socket.before it enters the tooth socket.
 The terminal branch of intra-septal arteryThe terminal branch of intra-septal artery
(RAMI PERFONATE) penetrate the alveolar(RAMI PERFONATE) penetrate the alveolar
bone proper.bone proper.
 Before the dental artery perforate the rootBefore the dental artery perforate the root
cannal,it divides into branches which supply thecannal,it divides into branches which supply the
apical portion of the PDL.apical portion of the PDL.

Vessels supplying the alveolar boneVessels supplying the alveolar bone
and PDLand PDLwww.indiandentalacademy.com

PHYSIOLOGICPHYSIOLOGIC
CHANGESCHANGES

 The internal structure of bone is adapted toThe internal structure of bone is adapted to
mechanical stresses. It changes continuouslymechanical stresses. It changes continuously
during growth ,alteration of functional stresses.during growth ,alteration of functional stresses.
 In the jaw structural changes are corelated to theIn the jaw structural changes are corelated to the
growth, eruption, movements, wear and loss ofgrowth, eruption, movements, wear and loss of
teeth.teeth.
 Bone resorption at any site is aBone resorption at any site is a CHEMOTACTICCHEMOTACTIC
PHENOMENONPHENOMENON that is initiated by release ofthat is initiated by release of
some soluble factor that attracts monocytes tosome soluble factor that attracts monocytes to
the target site.the target site.

 During bone resorption 3 process occur:-During bone resorption 3 process occur:-
1. Decalcification1. Decalcification
2. Degradation of matrix2. Degradation of matrix
3.Transport of soluble product3.Transport of soluble product

DECALCIFICATIONDECALCIFICATION
 Calcified matrix is resistant to proteases of allCalcified matrix is resistant to proteases of all
kind so bone must first be decalcified.kind so bone must first be decalcified.
 Bone decalcification occurs at ruffled border ofBone decalcification occurs at ruffled border of
osteoclast.osteoclast.
 By secretion of of organic acid chelation of boneBy secretion of of organic acid chelation of bone
and hydrogen ion occur which increases theand hydrogen ion occur which increases the
solubility of hydroxyapatite crystals.solubility of hydroxyapatite crystals.

IRREGULAR SURFACE SHOWINGIRREGULAR SURFACE SHOWING
BONE RESORPTIONBONE RESORPTION

DECALCIFIED FACIAL-LINGUALDECALCIFIED FACIAL-LINGUAL
SECTION THROUGH A JAWSECTION THROUGH A JAWwww.indiandentalacademy.com

HIGHER MAGNIFICATION OFHIGHER MAGNIFICATION OF
DECALCIFIED SECTIONDECALCIFIED SECTION

DEGRADATION OF MATRIXDEGRADATION OF MATRIX
 After the decalcification pieces of matrix areAfter the decalcification pieces of matrix are
released by the activity of-released by the activity of-
CATHEPSIN B1CATHEPSIN B1 (lysosomal acid protease)(lysosomal acid protease)
COLLAGENASE ENZYMECOLLAGENASE ENZYME
 Collagenolytic activity takes place outside theCollagenolytic activity takes place outside the
osteoclast and occurs at the specific site on theosteoclast and occurs at the specific site on the
tropocollagen molecule.tropocollagen molecule.
 This site is 1/3This site is 1/3rdrd
the distance from carboxyl endthe distance from carboxyl end
of the molecule.of the molecule.

TRANSPORT OF SOLUBLETRANSPORT OF SOLUBLE
PRODUCTSPRODUCTS
 After the degradation of matrix,After the degradation of matrix,
breakdown product of the bone mustbreakdown product of the bone must
be transported to the ECF and to thebe transported to the ECF and to the
blood vascular system.blood vascular system.

INTERNALINTERNAL
RECONSTRUCTIONRECONSTRUCTION

 During the growth of maxilla and mandibleDuring the growth of maxilla and mandible
bone is deposited on the outer surface ofbone is deposited on the outer surface of
cortical plate.cortical plate.
 In the mandible with its thick and compactIn the mandible with its thick and compact
cortical plate bone is deposited in the shape ofcortical plate bone is deposited in the shape of
basic or circumferential lamellae.basic or circumferential lamellae.
 When lamellae reaches certain thickness they areWhen lamellae reaches certain thickness they are
replaced from inside by HAVERSIAN BONE.replaced from inside by HAVERSIAN BONE.

HAVERSIAN REMODELLINGHAVERSIAN REMODELLING

 Reconstruction is correlated to theReconstruction is correlated to the
functoinal and nutritional demand of thefunctoinal and nutritional demand of the
bone.bone.
 In haversian canal closest to the surface,In haversian canal closest to the surface,
osteoclast differentiate and resorb theosteoclast differentiate and resorb the
haversian lamellae.haversian lamellae.
 The resorbed bone is replaced byThe resorbed bone is replaced by
proliferative loose connective tissue. Thisproliferative loose connective tissue. This
area of resorption is called RESORPTIONarea of resorption is called RESORPTION
TUNNEL or CUTTING CONE.TUNNEL or CUTTING CONE.

 The scalloped outline of howship’s lacunae thatThe scalloped outline of howship’s lacunae that
turns their convexity towards the old boneturns their convexity towards the old bone
remains visible as a darkly stained cementingremains visible as a darkly stained cementing
line, a REVERSAL LINE.line, a REVERSAL LINE.
 Lines correspond to the rest period in anLines correspond to the rest period in an
otherwise continuous process of boneotherwise continuous process of bone
apposition. They are called RESTING LINES.apposition. They are called RESTING LINES.

BONEBONE
DEFECTSDEFECTS

 Bone defects can be enumerated asBone defects can be enumerated as:-:-
1. FENESTRATIONS1. FENESTRATIONS
2. DEHISCENCE2. DEHISCENCE
3. LEDGES3. LEDGES
4. HEMISEPTA4. HEMISEPTA
5. EXOSTOSIS5. EXOSTOSIS
6. CRATERS6. CRATERS

BIBLIOGRAPHYBIBLIOGRAPHY
 CLINICAL PERIODONTICS-CLINICAL PERIODONTICS- CARANZACARANZA
 TEXTBOOK OF ORAL HISTOLOGY-TEXTBOOK OF ORAL HISTOLOGY-
ORBANSORBANS
 CLINICAL PERIODONTOLOGY ANDCLINICAL PERIODONTOLOGY AND
IMPLANT DENTISTRY-IMPLANT DENTISTRY- JAN LINDHEJAN LINDHE
 ORAL HISTOLOGY DEVELOPMENT,ORAL HISTOLOGY DEVELOPMENT,
STRUCTURE AND FUNCTION-STRUCTURE AND FUNCTION- A.R.TENA.R.TEN
CATECATE

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