8بسم الله الرحمن الرحيم

Developmental Disturbances of Bone

><Hemifacial hypertrophy :

><Hemifacial atrophy (Romberg syndrome) :

><Cleft lip and palate :

>-also known as Parry-Romberg Syndrome and in this condition the patient has degenerative condition affecting one side of the face and they thought that it might be because of alterations in the sympathetic nervous system .

>-There are many "theories" such as: Hereditary, trauma, infection or as mentioned before (alteration

in the sympathetic nervous system).>-Usually patient has Contra lateral epilepsy the Teeth may

exhibit delayed development and Retarded tooth eruption unlike hemifacial hypertrophy ( macrodontia).

>-That is half of the face get enlarged more than the other half and when we say half of the face enlarged we mean the bone , the muscles, the teeth and even brain hemispheres which can lead to mental issues such as epilepsy or mental retardation so the teeth in the enlarged half will be macrodontia.

>-causes:There are many hypotheses about hemifacial hypertrophy ….. one of them is that there is neurovascular supply to the affected side that will lead to Increased incidence of visceral tumor.

>-It may be bilateral or unilateral (on side or both sides)>-It may affect the soft tissue only or the soft tissue and the

palate and sometimes the alveolar bone can be affected and there may be a problem when the oral and nasal cavities are opened to each other.

>-The mildest form of it is to have a bifid uvula. >-It may be viral infection, hereditary, familial and other

theories that we will talk about them in other courses .

8><Stafne bone defect (lingual mandibular salivary

gland depression):

><Focal Osteoporotic Bone Marrow Defect :

><Cleidocranial dysplasia :It is a genetic disease that affects the bones of the face, the skull and the clavicle.

Cause: Fontanels are remaining open or have late closure and the sutures remain open.

Features: >-The frontal bone, parietal bone and occipital bone are prominent.

>-The patent may have a depression in the maxilla (hypoplastic maxilla) so the mandible aperies prominent .

>-The palate will be v-shaped and narrow . >-The teeth will be delayed in eruption because of:

A. multiple impacted supernumerary teeth that interfere with eruption of normal teeth (physical barrier) .B. lack of cellular cementum .

>-Because the permanent teeth are delayed to erupt, the deciduous teeth will remains for a longer period of time .

>-The patent may have no clavicles or malformed clavicles which causes hypermobility of shoulders.

><Craniofacial Dysostosis (Crouzon Syndrome) :It’s a genetic disease manifestations are due to early closure of sutures (synostosis) because of a mutation in FGF2 (fibroblast growth factor tow) gene.

>-It looks like a cavity (a radiolucent lesion) within mandible on the ligulae aspect of it specifically below the mandibular canal .

>-It may contain salivary gland tissue (by the act of pressure of sub mandibular gland) … it may contain muscles or nerves or it can be empty (we can determined by a biopsy) .

>-We should remember that it’s not a true cyst.

>-Will defined edentulous area After extraction, the defect is filled with hematopoietic bone marrow (blood forming).

>-More in females (because of iron deficiency anemia)>-No pain or expansion.

>-It has an undefined shape .>-Biopsy may be needed to rule out malignancy.

8Because of early closure of the sutures the brain enlargement will make concavities in the inner aspect of the skull .

Features:“>-frog-like” face due to midface hypoplasia and exophthalmos (eyes

are protruded) . >-Hypoplastic maxilla which will cause malocclusion, high-arched

palate, sometimes cleft. >-Short upper lip, Parrot-beak nose.

>- Increased interpupillary distance and they may have difficulties in vision.

><Mandibulofacial dysostosis (Treacher Collins syndrome) :It’s a genetic disease associated with increased paternal age , it will affect the first and second branchial arches .

Features: >-Midface hyperplasia,Underdeveloped mandible, hypoplasia of

condyle and coronoid and Lateral facial clefting . >-Depression in the bone at lateral aspect of the eyes “coloboma” and

the eyes will look like dripping down from the outer side. >-Cleft between the mandible and the ear and the ears are

malformed .

Treatment: cosmetic surgery .

We finish talking about the Developmental Disturbances of Bone and in the next page we will start talking about Disorders of teeth other than caries.

Disorders of teeth other than caries

Disorders of eruption and shedding:

><Natal and neonatal teeth:

8

Natal teeth are deciduous teeth that are presence in the infant mouth at birth; if the teeth erupt within the first 30 days of life we call it Neonatal teeth.

Cause: the normal tooth germs in superficial locations subsequently.

>-These teeth are characterized by hypoplastic enamel and the roots are absent .

>-It will cause laceration and trauma to the tongue and the mother (during breastfeeding); these teeth are loose and easy to swallow so it’s better to be extracted .

>-80% of the cases are in the mandible.

><Premature eruption of teeth: >-The early eruption of permanent teeth if it was generalized it is mainly

caused by endocrine disorders (hyperthyroidism or high growth hormone) and it may affect the deciduous teeth too.

>-If it was localized (two or three teeth are affected) it may be because the tooth germ is superficially.

><delayed eruption of teeth :Cases :

>-If it was generalized an endocrine disorder is the main cause (hypothyroidism or low growth hormone) .

-Nutritional (iron deficiency, folic acid deficiency or B12 deficiency) -Chromosomal abnormalities (Down syndrome).

>-If it is localized it may be because of traumatic displacement of the tooth germ.

>-It also may be because of abnormally large crowns or cleidocrainial dysplasia.

*Note: the premature loss of deciduous teeth will cause delayed eruption in permanent teeth .

><Premature loss of teeth:

Causes: >-Dentin hyperplasia type 1 (rootless teeth ) .

>-Dental caries>-Periodontal disease

>-hypophosphatasia

><Persistence of deciduous teeth:Causes:

8>-Failure of eruption of permanent teeth because the permanent teeth may be

missing or displaced or impacted . >-Entire dentition: in cleidocrainial dysplasia

><Impaction of teeth:Unerupted or partially erupted beyond the time of normal full eruption.

>-Third molars, mandibular premolars, maxillary canines are the most common teeth to be impacted.

Causes:>-Abnormal position of tooth germ

>-Lack of space in the jaws>-Supernumerary teeth, cysts, tumors

Complications :Resorption of impacted teeth or adjacent erupted teethDevelopment of odontogenic cysts and tumors

><Re impaction (infraocclusion) :>-At first the tooth erupt normally then roots get ankylosed to the bone followed

by deficient development of the alveolar process, and the adjacent teeth tilt over it so it will be less provenance than the adjacent teeth, it will appear impacted and we will call it submerged tooth.

*you have to remember the term “submerged tooth ”

Causes:It may be not well known, but congenitally absent of the permanent tooth.

*the deciduous second molar is most commonly affected.

Attrition:

8Loss of tooth structure and substance as a resultof tooth to tooth contact due to physiologic

or pathologic causes

Physiological

it occur in Incisal edges of incisors and Occlusal surfaces of molars

**when the loss of enamel occur the loss of dentine will be easy and fast

and we will have Cup shaped depression on the occlosal surfaces of teeth ( and we call them wearing facets ) .

**The sarfeces that are mainly get attrition are : the Palatal cusps of maxillary teeth and the Buccal cusps of mandibular

teeth.

**attrition may also occur in the contact points " the highest point in the occlusion area " to contact areas and that mean that

there will be wider contact area.

**more in men.

**depend on the type of the food and daily habits ( such as eating nuts ).

Pathological

Causes:

when there is Abnormal occlusion because of crowding or malocclusion

Bruxism : if the patient has clenching habit " some people have this habit where their teeth forcefully contacted specially during

sleep or rest position " Abnormal tooth structure such as amelogenisis imperfecta or detinogenisis imperfecta

there will be Formation of reactionary dentin on pulpal surface to prevent pulp exposure and preventing from having truma to the pulp .

and for the Dentine it will be discolored and hypersensitive ( because it has protein more than the enamel )

8 Abrasion

its always pathological

its Pathologic wearing of teeth by friction of a foreign body- independent

of occlusion

Tooth brush abrasion:If you use a hard tooth brush or you used Horizontal method of brushing which lead to Exposed root surface and cervical region of

teeth.

the most teeth that are affected due to heavy occlusal load are : the canine ( mainly ) and the pre-molars and specially at the

cervical and this is what we call abfraction .

Habitual abrasion such as when the patient put a pen or pencil in his / her mouth or the pipe smokers .

Occupational abrasion like in salons when the hair-dressers hold hair grips between their teeth. seed notch is another example for abrasion.

Clinically: the way the we see the abrasion is wedged shaped with sharp angels .

Erosion

Loss of tooth substance by a chemical process other than bacterial action

this chemical material could be coming from the stomach by frequent vomiting or stomach acidity regurgitation or patient who induce vomiting such as who have anorexia nervosa ( they don’t eat enough ) or bulimia nervosa ( they eat a lot and think that they didn't)

Labial surfaces of maxillary teeth and palatal of posteriors are the most affected in Dietary erosion

Drinking a lot amount of soda or citrus food Clinically: the way the we see the erosion is shallow broad concavities

8 **if the affected teeth are the maxillary ….. because of Regurgitation

if the mandibular ……… soda , citrus food

Forgive us for being late ……. And for any mistake ……

Done by: Abdallah Zireeni

Mn el end