Lecture 3, Disorders of Development 3 (script)

8/4/2019 Lecture 3, Disorders of Development 3 (script)

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Disturbances in Development

Continued (Dental & Facial)

Dentine Dysplasia Type 1-(Also called: Rootless teeth) has

shortening of root lengths with variable severity (can be very short or

somewhat short) the shorter the root is the more probable that the tooth

will be lost prematurely, Dentine dysplasia also contains Obliteration of

pulp chambers & peri-apical lesions, however the outer view/Coronal view

appears normal. The only sign of Dentine Dysplasia type 1 is the looseningof teeth; upon preforming a radiograph the obliterated pulp, short roots &

Lesions can be seen.

Dentine Dysplasia Type 2-Has two different clinical appearances one for

primary teeth and a different set of clinical appearances for permanent teeth. In

Primary teeth their appearance resembles the color of dentinogenisis imperfecta


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(Yellowish/Brownish color due to damaged dentine), as well as the presence of

obliterated roots (also present in dentinogenesis imperfecta). In Permanent Dentition

the root length is Normal and the Pulp is present and coronal pulp is enlarged and

extends radicularly resulting in a flame shaped appearance, pulp channels arenarrow but not obliterated, but they may contain pulp stones.

Roots

Length/MorphologyPulp Chambers

Dentine Dysplasia

Type 1Shortened/Rootless Obliterated

Dentine Dysplasia

Type 2 Normal Length

Present, Coronal is

Flame shaped and

Radicular is narrow

Regional Odontodysplasia- (also called Ghost teeth) in this condition ALL

OF THE TOOTH STRUCTURES in one area have abnormalities (dentine, pulp & Enamel

are all abnormal) the gingiva surrounding the teeth is also abnormal (thick gingiva).Regional Odontodysplasia is considered idiopathicbut the most likely theory is that

its caused by Ischemia or an abnormal blood flow to the affected region (teeth +

surrounding tissue). On a radiograph you can see very thin enamel and dentine, but

an enlarged pulp (giving it the ghost tooth appearance). The teeth in the affected

area usually dont erupt because the erupting force is

abnormal and the overlying gingiva is very thick and

calcified.

**Note: Remember that Turners tooth only affects

ONE SINGLE TOOTH while Regional Odontodysplasia

affects several teeth and the surrounding area.


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Hypophosphatasia-is another cause for premature/early tooth loss, caused

by a decrease in Alkaline Phosphatase (an enzyme NOT THE SAME AS PHOSPHATE)

resulting in abnormal cementum and abnormal alveolar bone. Abnormal cementum

leads to failed attachment of PDL fibers, leading to abnormalities in tooth attachmentto its sockets. Alkaline phosphatase is very important for bone formation and

deposition meaning that abnormalities In it will cause a decrease in levels/formation

of cementum and alveolar bone, even if calcium and phosphate levels are normal.

Hypophosphatasia also leads to delayed eruption of the teeth because the eruption

force (which depends on force originating from PDL fibers and tooth socket) is

abnormal, this may also lead to spontaneous loss of BOTH DENTITIONS meaning that

Hypophosphatasia is present for long periods of time, meaning that it is a GENETIC

DESIEASE autosomal recessive.

Developmental Diseases in Soft Tissue-

Commisural Lip Pit- This is a very common developmental change that you

will see a lot in the oral diagnosis clinic, a pit appears in the corner of the mouth,

possibly present bilaterally (on both sides). It is simply an invagination or an inwards

depression in the epithelium of the mouth that is a BLIND TRACT meaning that it does

not open into any other tracts or ducts, it may contain drainage from minor salivary

glands. This developmental change is usually autosomal dominant (genetic/Familial),

however this pit has no signifance.


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Paramedian Lip Pits- Ifyou draw a

midline through the lower lip you will see two

pits surrounding the midline, these are called

paramedian pits. Paramedian pits are very rareand may be associated with cleft pallet or Van

Der Woude Syndrome.

Double Lip-is an excess fold of tissue that is

present on the inner aspect of the upper lip

especially visible when the patient tenses the upper

lip (like smiling). Double lip may be associated with

Ascehr Syndrome which is accompanied with

drooping of the eyelids and non-toxic goiter

(enlargement of the thyroid gland, without an

increase in thyroid secretions).

Frenal Tag-A very common condition

that must be known to avoid confusion with a

polyp or fibrous tissue enlargement, when in fact

it is a small excess/projection from the maxillary

labial frenum that is non-pathogenic and does

not cause any problems, it can be Familial but it iscomposed of Normal Oral Mucosa.


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Ankyloglossia-(Ankylo= tied / Glossia= related to the tongue) is a condition

when the tongue is either attached to the floor of

the mouth ANTERIORLY or to the gingiva. The

normal location of the lingual frenum (whichattaches the tongue to the floor of the mouth is

in the posterior part of the mouth) in

Ankyloglossia the lingual frenum is located

anteriorly at the tip of the tongue tying the

tongue down to the floor of the mouth; limiting

the movement of the tongue which may lead to complications such as problems, in

speech, swallowing, gingival problems/gingival recession.Most forms ofankyloglossia prevent the patient from being able to pronounce the letter R.

Macroglossia-Is in an increase in the size of

the tongue due to a congenital disorder such as

Down syndrome (Primary cause) or tumors/cancer,

lymphoangioma, hemangioma, neurofibroma,

amyloidosis (protein deposition in tissues due to

inflammation), acromegaly (hormone changes),

cretinism (deposition in tissues).

Fordyce Granules-Usually present at the junction between the upper

vermillion border and the buccal mucosa. Fordyce granules are Ectopic Sebaceous

glands found intra-orally, but since there is no hair in the oral cavity Fordyce granules

form in these sebaceous glands, they appear clinically as yellowish spots.


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Leukoedema-manifests as a whitish appearance on the buccal mucosa, the

whitish color on the buccal mucosa disappears UPON STRETCHING. It has a white

milky appearance that disappears upon

stretching giving a normal pink appearance.THIS CONDIIOTN IS NOT CAUSED BY EXCESS

KERATIN it is caused by Intra-cellular edema in

the prickle cell layer (intra-cellular edema

CANNOT be removed) which leads to an

increase in the thickness of the oral mucosa

blocks the view of the blood vessels beneath

(in normal condition blood vessels beneath

oral mucosa give the mucosa its pink color).

*Increase in thickness of epithelium = whitish color

*Increase in Vascualrity with normal thickness = Pinkish color

White Sponge Nevus-Is a defect in keratin types K4 & K13 giving abnormal

structure or amount giving a whitish appearance of the buccal mucosa as well as

abnormal keratinization of other mucosal surfaces (eyes, conjunctiva, nasal may

also appear whitish). White Sponge Nevus is autosomal Dominant found above and

below the occlusal plane and extends posteriorly towards the retro-molar area to the

alveolar mucosa (basically the white sponge nevus IS NOT CAUSED by keratinization

of tissue in response to teeth biting down on the mucosa) -

it is present from birth And does NOT DISSAPEAR UPON

STRETCHING. Histologically you can find Hyperkeratosis

(increase in keratin), acanthosis (increase in number of

epithelial cells), and possibly edema of spinous layer.


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Lingual Thyroid nodule-Forms when the thyroid gland does not go to its

proper position during formation and attaches near

foramen cecum (on the dorsum of the tongue). It is

possible that the patient may be missing the actualthyroid gland completely and that the lingual thyroid

nodule is the only thyroid tissue in the patients

body. If the lingual thyroid does not interfere with any

oral processes (mastication, speech, swallowing etc.)

then there is no need for it to be removed; however of

it does interfere it must be surgically removed (if this is

the only thyroid tissue in the patient, removal may

lead to shock).

Oral Tonsil-are tonsils found sublingually on either side of the lingual frenum

or on the lateral sides of the tongue that contain lymphoid tissue, these tonsils act as

normal tonsils and are part of the tonsil ring of waldeyer and may even enlarge during

infection. These tonsils are common areas for Oral lympho-epithelial cysts

Retrocuspid papilla-Will be discussed in the lab.

Hemifacial Hypertrophy-(Hemi= half,

Facial = Face half the face) One side of the face is

Hypertrophied/larger than the other side the face,

skin, muscles, tongue, teeth, gingiva, soft tissue, and

the brain ... etc. are hypertrophic on the affected side.


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This condition can lead to Mental retardation and a seizure in 15-20% of the cases,

Hemi facial hypertrophy is one of the few conditions that displays TRUE

MACRODONTIA.

PassiveHemifacial Atrophy-(Parry-Romberg Syndrome) this condition is

almost the exact opposite of hemi facial hypertrophy, where the child is born with a

normally proportional face but after a certain age (around 6 years) one side of the face

begins to completely degenerate (including skin, muscle and bone). This condition

usually affects the left side of the face more than the right and can lead to problems in

the brain (due to cramping of space- BRAIN DOES NOT SHRINK) leading to seizures

and epilepsy ON THE CONTRALATERAL SIDE of the body (the side opposite to the

atrophied side has seizures). The cause of hemi facial atrophy is not completely

understood but it is possibly related to Sympathetic Innervation. Teeth still being

developed when atrophy begins (permanent teeth are still developing at the age of 6

years) may have delayed development or eruption.

Cleft Lip and Pallate-we wont go into too much detail because we willdiscuss this later, just know that the mildest

form of Cleft palate is the bifid uvula, the

most sever form is when the cleft palate

perforates the whole bone and

communicates with the nasal cavity. Cleft lip

and palate are commonly associated with

supernumerary teeth or hypodontia.


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Stafne bone defect -(lingual mandibular salivary gland depression)a defect

found on the lingual aspect of the

mandible that appears as a depression

caused by the salivary glands. In the

radiograph you can see the Molar area of

the mandible, below the mandible you

have the IV canal beneath that there is a

radiolucent rounded area, that can be

confused with a cavity inside the bone ITIS NOT A CAVITY IT IS A

DEPRESSION/CONCAVITY, this was caused by the lingual salivary glands pushing

against the mandible during formation forming the depression, this depression may

be confused with bony diseases or metastatic cancer, but initially when we see a

radiolucent area beneath the IV canal we should think about stafne bone defect.

When this area is biopsied you will find Salivary gland tissue (usually sub mandibular

but rarely sub lingual)

Focal Osteoporotic Bone Marrow Defect-is presented on a radiograph as

a lesion/ finding in the bone that contains BONE

MARROW TISSUE, in this case the bone marrow is

hyper-plastic and active (in anemic females this

marrow will be activated to produce more RBCs).

Appears as an ill-defined relatively radiolucent on

the radiograph, once biopsied you will find bone

marrow and lipid cells. This condition may occur


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in edentulous areas after tooth extraction, present as FOCAL osteoporotic, still it

SHOULD NOT be confused with tumors.

Cleidocranial Dysplasia-Is a genetic disease that has

Abnormal growth of bone the most alarming of which is ABSENCE

OF CALVICLES leading to approximation of shoulders and

hypermobility of the shoulders, The skull is also abnormally wide

(due to large parietal bones) this is due to DELAYED CLOSURE OF

FONTANELS or sutures. The Maxilla appears hypoplastic and

retruded the patient also has A V Shaped Pallet this condition is

also accompanied by multiple supernumerary impacted teeth as

well as abnormal/lack of cellular cementum formation.

Crouzon Syndrome-Is a condition

where the cranial sutures close prematurely

leaving no room for the brain to

expand/develop, leading to an abnormally

shaped skull, Exopthalmic eyes (bulging eyes),

affected vision (damaged optic nerve), Nose

appears beak like, maxilla is depressed along

with the sinus area, short upper lip and lower

lip appears protruded.


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Treacher Collins syndrome-appears to be involved with Paternal age (the

older the father is the more likely it is to occur), in this condition there is a defect in

the 1st and 2nd branchial arches which

are responsible for formation of theface defected face. In treacher

Collins syndrome THE MANDIBLE IS

RETRUDED AND HYPOPLASTIC

(underdeveloped) as well as abnormal

ears, the TMJ and its joints are also

hypoplastic and the maxilla is also

hypoplastic, the eyes are depressed

and have depression beneath them.

Done By: Ali Hassan Al-Qudsi

Lecture 3, Disorders of Development 3 (script)

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