Lamina dura/ oral surgery courses

 A radiographic term denoting the plate
of compact bone (alveolar bone) that
lies adjacent to the periodontal
membrane
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 Lamina dura -- hard layer
 Radiograph of the normal tooth
demonstrates that the tooth socket is
bounded by a thin radiopaque layer of
dense bone, that is lamina dura
 This name is derived from the radiographic
appearance

 Anatomically, it is the alveolar bone proper
that surrounds and supports the tooth.
 It is continuous with the cortical bone at the
alveolar crest.
 Degree of mineralization is almost similar to
the trabeculae of the cancellous bone.

 Histologically, it is the compact variety of
bone
 It is perforated by many openings that
carry branches of interalveolar nerves and
blood vessels into periodontal ligament,
hence it is known as Cribriform plate
 It is also called as Bundle bone as the
bundles of fibers of periodontal ligament
gets embedded in it as Sharpeys fibers.

THE APPEARANCE OF THE LAMINA DURA ON
RADIOGRAPH
 It may vary depending on the direction of beam
 When the x-ray beam is directed through the
relatively long expanse of the structure, the
lamina dura appears radiopaque and well
defined
 When the beam is directed obliquely, it appears
more diffuse or may not be discernible

 When tangentially through the thickness of bone, then
there is the observed attenuation
 Even if the supporting bone is healthy and intact, the
identification of the lamina dura which is completely
surrounding each root of the tooth is difficult or it is
usually evident to some extent about the root.

Lamina Dura

 Small variations and disruption in the continuity of the
lamina dura on the radiograph may represents the
superimpositions of trabeculae and nutrient canals
passing in the vicinity.
 The thickness and the density of the lamina dura vary
with the amount of occlusal stress to which the tooth is
subjected. Accordingly lamina dura on the radiograph
is wider and denser around roots of the tooth in heavy
occlusion and thinner and less dense in one with less or
not subjected to occlusal function.
 If mesial or distal surface of the root presents two
elevations in the path of the beam then the image
shows the double lamina dura.

Nutrient canal with radiopaque cortical borders
from mandibular first molar.

 In spite of all this, the appearance of the lamina dura is of
diagnostic significance and it is necessary to examine
lamina dura around each tooth.
 Presence of the lamina dura around the apex of the tooth
strongly suggest the vital pulp.
 However the absence of the lamina dura around the apex in
radiograph may be normal.
 Such as it may be absent in the molar root extending into the
maxillary sinus.
 The clinician is advised to consider other signs and
symptoms and integrity of lamina dura to reach to the
diagnosis.

Lamina dura is poorly visualized on the distal surface
of tooth but clearly seen on mesial surface.

 When the apices of the molars are projected over the
canal, the lamina dura may be overexposed, giving the
impression of missing lamina dura or thickened
periodontal ligament space that is more radiolucent than
which is apparently normal to the patient.
 Hence other clinical procedure may be employed to
ensure the soundness of the tooth such as vitality test
 The mental foramen over the apex of second premolar
may simulate periapical disease but the continuity of
the lamina dura around the apex, indicate the absence
of periapical anomaly.

Mandibular canal superimposed over the apex of molar causes
the image of pdl space to appear wider.
The presence of intact lamina
dura indicate that there is no periapical disease.

Mental foramen may simulate periapical pathology
Lamina dura around the apex indicate absence of any pathology

Conditions associated with involvement of the
lamina dura
 PERIAPICAL INFLAMMATORY LESION
 PERIODONTAL DISEASE
 ORTHODONTIC TOOTH MOVEMENT
 EXTERNAL ROOT RESORPTION
 SUBLUXATION
 INTRUSION
 MALIGNANCY– SQUAMOUS CELL CARCINOMA
 OSTEOSARCOMA
 MUCOEPIDERMOID CARCINOMA
 LEUKEMIC INFILTRATION
 LYMPHOMA
 HYPOCROMIC ANEMIA,
 TRAUMATIC BONE CYST
 PERIAPICAL CEMENTAL DYSPLASIA

 CENTRAL GIANT CELL GRANULOMA
 FIBROUS DYSPLASIA
 PAGET`S DISEASE
 HYPERPARATHYROIDISM
 CUSHING`S SYNDROME
 RENAL OSTEODYSTROPHY
 IN RICKETS, HYPOPHOSPHATASIA AND HYPOPHOSPHATEMIA,
 HYPOTHYROIDISM
 OSEOMALACIA
 AGRNULOCYTOSIS
 THALASEMIA

PERIODONTAL DISEASE
 The crest of the alveolar bone is continuous with
lamina dura of adjacent tooth and forms sharp angle
with it
 Height of the alveolar crest lie at the level
approximately 1to1.5mm below the level of the CE
junction of the adjacent teeth
 Between the anterior teeth, the alveolar ridge is usually
pointed and has a dense cortex
 Between posterior teeth, the alveolar crest is parallel to
the line joining the adjacent CE junctions

oThe bony junction of the alveolar crest and the lamina dura of the
posterior teeth forms the sharp angle/junctions
oRounding of these sharp junctions is indicative of the periodontal
disease, of the early stage.

PERIAPICAL INFLAMMATORY LESION
 Radiographic features of the periapical
inflammatory lesions vary depending on
the time course of the lesion
 Significant pulpal involvement causes the
loss of lamina dura followed by the loss of
periapical bone at the root apex.

Early involvement of pulp without loss of lamina dura in premolar
In contrast there is loss of periapical bone and loss of LD
in second molar

Sclerosing lesion with small region
of bone loss with PDL widening
Loss of lamina dura

External root resorption
 It is commonly seen on cervical and apical region
 When lesion begins at the apex it caused smooth
resorption with blunting of the apex
 Bone and the lamina dura follows the resorbing root
with the normal appearance around the shortened
root
 However, the external resorption due to periapical
inflammation leads to the loss of lamina dura around
the apex.

External root resorption with loss of tooth structure
note the wide opened pulp canals and intact lamina dura

MALIGNANCY
 Malignancy results in the irregular widening of
periodontal ligament with destruction of lamina
dura

Solid arrows :- ragged bone margins
Hollow arrows :- root resorption with loss of lamina dura

Multilocular radiolucency with loss of lamina dura and
With inferior displacement of mandibular canal.

 Leukemic infiltration of the mandible may lead to
generalized rarefaction and destruction of the lamina
dura and the irregular widening of the periodontal
ligament space

Partial loss of lamina dura

Irregular widening of PDL space
and destruction of lamina dura.
LYMPHOMA

Traumatic bone cyst
 The lesion involves all bone around the
roots of the teeth but leaves the lamina
dura intact or only partly disrupted
 Similarly sparing of the cortical boundary of
the crypt around the developing tooth is
characteristic.
Lamina dura is intact in TBC

Central giant cell granuloma
Often displace and resorb the teeth with lamina dura of teeth within the lesion
usually missing

Distinct lamina dura disappears due to abnormal bone changes

PAGET`S DISEASE
 The lamina dura may become less evident
and may be altered in abnormal bone
pattern
 Hypercementosis may develop on few or
most of the teeth in the involved jaw, which
may be irregular
 Teeth may become spaced or displaced in
enlarging jaw.

Loss of lamina dura and some
Hypercementosis of teeth.

Hyperparathyroidism
 About 10% of the patient shows loss of lamina
dura(either partial or complete).
 Depending upon the duration and severity of the
disease, loss of lamina dura may occur around one or
all the remaining teeth
 Loss of lamina dura may give the root the tapered
appearance because of the decreased image
contrast

Cushing`s syndrome
 Primary feature is generalized osteoporosis
 Demineralization may lead to partial loss of
lamina dura
 Teeth may erupt prematurely

Cushing’s syndrome manifested in jaws as thinning of lamina dura
Cushing’s syndrome

Generalized osteoporosis and
white arrow showing
missing lamina dura
Cushing’s syndrome

Renal osteodystrophy
 Lamina dura may be absent or less apparent
when there is bone sclerosis
Areas of radiolucency due to loss of bone mass, loss of lamina dura and
Sclerotic bone pattern around the tooth.

Loss of lamina dura , Sclerotic bone pattern around the tooth and
loss of distinct inferior border cortication

Rickets, hypophosphatasia &
hypophosphatemia
 lamina dura may become thin, sparse or entirely
absent
 The cortical boundary of the follicle may be thin or
missing

Trabeculae become
reduced in number,
density and thickness
Associated with
hypoplasia of
developing dental
enamel if disease
occurred before 3 years.
Lamina dura may be
thin or missing.

Rarefaction and loss of
lamina dura in some areas.

Delayed eruption, short roots
and thinning of lamina dura

Overall radiolucent appearance
and sparse trabeculae. Lamina
Dura is thin in long standing cases.

Loss of PDL space and lamina dura

Trabeculae are coarse and lamina dura thin , with short roots

 Lamina Dura is an important structure in radiographic
interpretation which has various appearances not only
in pathologies but also in normal course, so it is a
valuable adjunct to diagnosis.

REFERENCES
 White and Pharoh, Oral Radiology, Diseases of bone
manifested in jaws: 5th
edition, Mosby publishers. p98, 485-
517.
 Eric Whaite , Essential of dental Radiography & Radiology,
periapical tissues and inflammatory changes p 185-188: 3rd
edition, Churchill Livingston.
 H M. Worth, Principles and Practice of Oral Radiological
interpretation; Year book medical publisher, Reprint 1969; p
18,24,36,58.

 Meredith & Massey, fundamental physics of radiology,
3rd
edition, Varghese publishers, p91.
 Haring and Jansen, Dental Radiography, 2nd
ed, W.B.
Saunders.
 Robert p. Langlais, Principles of dental imaging; chapter
18, Radiological diagnosis of periapical diseases1st
edition, Liippincott williams and wilkins publication. 1997
P 413-414.

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