Etiology of Malocclusion Local Causes PDF

# ETIOLOGY OF MALOCCLUSION LOCAL CAUSES **Etiology "causes" of malocclusion may be:** - General causes "next lecture" - Local causes of malocclusion: - Congenitally missing teeth - Teeth of abnormal size and shape - Abnormal labial frenum - Premature loss of deciduous teeth - D...

# ETIOLOGY OF MALOCCLUSION LOCAL CAUSES **Etiology "causes" of malocclusion may be:** - General causes "next lecture" - Local causes of malocclusion: - Congenitally missing teeth - Teeth of abnormal size and shape - Abnormal labial frenum - Premature loss of deciduous teeth - Delayed eruption of permanent teeth - Trauma - Supernumerary teeth (extra tooth than normal number) - Abnormal eruptive path - Abnormal pressure habits - Prolonged retention of deciduous teeth for a longer time than normal. - Loss of permanent teeth (fall out or extracted) - Local pathological factors **Partial anodontia** - missing one or more teeth **"Oligodontia"** - missing more than 6 teeth **Congenital missing teeth can lead to drifting of adjacent teeth in their place** May be associated with ectodermal dysplasia, a hereditary condition in which there is a dry, coarse skin, fine hair, defects of the nails, and often absence of sweat glands. **The most commonly missing teeth are:** 1. Upper and lower third molars (wisdoms) - not a malocclusion due to evolution & lack of space for them 2. Upper lateral incisors 3. Lower second premolars **The maxillary canines may erupt mesially to the deciduous canines into the space of the missing laterals. Or it may give rise to a median diastema and to a space between the central incisor and the canine. (absence of laterals may lead to median diastema)** **Q: How to correct missing teeth?** | | | |:------|:---------| | 1-Close space | 2-Open space | | Canines replace the laterals and reshaped to resemble the laterals | Put canine in its normal position and open space to restore missing lateral by implant or bridge | ## Causes of median diastema: - Physiological spacing of permanent central incisors is normal at 7.5 years of age (Ugly Duckling Stage) and tends to close with the eruption of permanent lateral incisors and finally canines. - Familial pattern. - Small teeth in large jaws. (hereditary problem) → generalized spacing - Missing lateral incisors. - Misplaced lateral incisors due to crowding. - Peg shaped lateral incisors. - Supernumerary tooth or teeth between incisors e.g. mesiodens. - Median Cyst. - Abnormal labial frenum. (thick frenum) - Imperfect fusion at midline of premaxilla. (developmental abnormality → problem in bone) - Palatal expansion (rapid maxillary expansion) → in case of posterior cross bite is treated by expansion of maxilla resulting in diastema formation) | Palatal expansion | Missing laterals | Peg shape lateral | Abnormal labial frenum | |:-------------------|:---------------|:------------------|:-----------------------| ## Supernumerary Teeth: - Heredity plays a strong part in many causes and they are commonly associated with congenital defects as cleft palate. - **Supplemental tooth:** supernumerary tooth of normal size and shape - Not all supernumerary teeth are supplemental - **Mesiodens:** conical in shape (most commonly), smaller than adjacent incisors other shape (morphology) is rare, occurs most often singly although it may be present in pairs. - Most common supernumerary tooth with a prevalence 0.15-1.9% - Between 2 centrals of the upper and lower jaw and can cause median diastema - May be part of a syndrome, may found impacted - Higher frequency in males than females - Occasionally it is fused to one of the upper central incisors. These teeth may be normal in size and appearance and it is difficult to determine which one is the supernumerary (Supplemental teeth). - Removal of the supernumerary tooth usually allows the normal teeth to erupt or to return to their correct positions though appliance therapy may be needed. - Determine supernumerary teeth by: - Inspection and palpation. - Radiographs: - Occlusal film and periapical films. - SLOB RULE - Supernumerary teeth may be seen in the premolar area in some cases - Supernumerary tooth complications: - Failure of eruption of normal teeth - Root resorption of neighboring teeth - Midline diastema (as in Mesiodens) - Crowding - Displacement or rotation of adjacent teeth (deflection) ## Teeth of Abnormal Size and Form - Abnormal tooth morphology (size & shape) may be inherited or individual variant - Peg shape lateral. - The presence of an exaggerated cingulum or heavy marginal ridges can prevent the normal overbite and overjet - Development defects as - Amelogenesis Imperfect - Enamel Hypoplasia - Gemination (one tooth) - Dens-in- dent - Odontomas - Fusion (two teeth) - Hutchinson's & Mulberry molars. | Hutchinson's teeth | Mulberry molars | Odontomas | Germination | Gemination & fusion | |:-------------------|:---------------|:-----------|:-------------|:--------------------| ## Gemination (twinning of teeth) - Single tooth germ wants to divide producing a "double crown" or a "double root." - Usually incisors are affected - Can be seen in Deciduous & Permanent teeth - Recognized by a notch in the incisal edge of the affected tooth - Tooth counting is a normal number of teeth - Geminated central incisors are wider than normal incisors and are prominently notched ## Fusion - 2 adjacent tooth germs merge producing 1 tooth. - Fused by enamel or dentine or BOTH - The incisors are affected most commonly - More common in the primary dentition - The root canal can be shared or separate. - Tooth counting reveals decreased numbers. (The most important difference) - Etiology is unknown but may be due to trauma - Fused tooth crown is broader than non-fused adjacent teeth so it is similar to gemination **N.B: It is impossible to differentiate between fusion of supernumerary teeth from gemination** **So x-ray is important before endo or extraction** ## Anomalies of tooth size: Malocclusion due to size discrepancy between the arch and teeth (hereditary) ### Microdontia - Teeth are smaller than normal - True generalized microdontia: All the teeth are smaller than normal - Microdontia of a single tooth is common, It affects upper lateral incisor as (peg shaped lateral) & 3rd molar ### Macrodontia - Teeth that are larger than normal - True generalized macrodontia: All teeth are larger than normal. - Relative generalized macrodontia: presence of normal or slightly larger than normal teeth in small jaw gives the illusion of macrodontia. - Macrodontia of a single teeth as gemination ## Abnormal Eruptive Path: This is usually a secondary manifestation of the following: 1. Severe crowding 2. Supernumerary tooth or tooth fragments (odontomas) 3. Trauma to deciduous teeth, may turn the developing successor in an abnormal direction (may cause ankylosis) 4. Mechanical interference by early orthodontic treatment. 5. Eruption cysts 6. Ectopic Eruption: - A permanent tooth during its eruption may cause resorption of a neighboring deciduous or permanent tooth, rather than its predecessor. - Eruption of a permanent tooth into upnormal position - Maxillary first molar may cause abnormal resorption of the maxillary second deciduous molar, when it erupts under the distal convexity of this tooth. - Upper canines - Lower laterals ## Abnormal Labial Frenum: - Normally during eruption of permanent incisors, labial frenum position is between alveolar crest level and mucosa "away from interdental papilla" - Abnormally it remains at papilla level + thick and fibrous so it deflect the centrals - Thick abnormal labial frenum in between 2 centrals can cause diastema - **N.B. we should do frenectomy AFTER closing the diastema, why?** - Because after frenectomy there is a scar formation, which makes closing diastema more difficult - **Ortho first then frenectomy** ## Abnormal Pressure Habits ### Thumb Sucking - It is repeated forceful sucking of the thumb with associated strong buccal (buccinator muscles) and lip contractions. - The clinical aspects of this problem are divided into 3 distinct phases of development: - Normal and sub-clinically significant thumb-sucking: - This extends from 3 months to 2 years as most infants display a certain amount of thumb sucking during this period, &it resolve toward end of this phase - Clinically significant thumb-sucking: - This extends roughly from 2-4 years - If the child drops the habit by the end of the third year he may have no more than reduced overbite and increased overjet with some spacing in the maxillary arch - Active thumb sucking: - The child continuing this habit after 4 years of age will develop malocclusion. - Its severity depends on: Excessiveness = Intensity + Frequency + Duration - Intensity: how strong child sucks his finger - Frequency: how often is the sucking - Duration: how long the child sucks his finger (minutes or hours) - Excessive sucking is what causes the damage - Habit may exist but with small excessive small damage or effect - Causes of Thumb sucking: - If during first weeks of life so it is related to feeding problems - Some children suck thumb as a teething device during difficult eruption of a primary teeth - Thumb sucking can be a symptom of psychological disturbance to release emotional tension. - Effects: - Increase overjet due to - Labial Protraction of maxillary anterior teeth - Lingual tipping of mandibular retraction. - Anterior open bite. - Posterior cross bite: due to overactivity of buccinator compressing the maxilla - Narrow & high palatal vault (from compressed of the maxillary arch) - Retrognathic mandible: - Due to hyper active mentalis so increased pressure of the muscle on the mandible - Increase overjet leads to incompetence lips leads to anterior tongue thrust - Control of thumb sucking: - Advice - Reminders as Adhesive bandage & Nail polish - Habit breaking appliance - Maxillary expansion (correction of narrow maxilla) ### Tongue-thrusting - Tongue-thrust habit may be an etiologic factor to malocclusion, it is usually of two types: - Simple: in which the tongue thrust is associated with a normal or teeth together swallow. This type usually accompanies or is a result of thumb sucking habit. - Complex: While the teeth are separated tongue thrust between them at last stage of swallowing causing an anterior open bite as tongue thrust prevent normal dento alveolar structure development - Complex tongue thrust is associated with : (I) Mouth breathing (II) pharyngitis III) Tonsilitis - Tonsilitis: Tonsils are inflamed and swollen. Tongue press on enlarged pillars causing pain and as a reflex the mandible is dropped, the teeth become separated and the tongue thrusts between them during the last stage of swallowing - This will cause anterior open bite - Tongue thrust may be anterior or lateral - An anterior tongue thrust is an important etiological factor for the anterior open bite - Tongue thrust can be treated by: 1- fixed palatal crib 2-bluegrass appliance 3-T4K ### Lip-sucking Lip-biting - Usually associated with class II division 1 (due to increased overjet) - May appear by itself it may be seen with thumb sucking. - Most common in lower lip - Causing maxillary incisor labioversion (protrusion) and mandibular incisor lingual inclination (lingo-version) (retrusion) - So may result: open bite and retruded chin due to muscle overactivity ### Nail-Biting - Nail-biting is mentioned frequently as a cause of tooth malposition - It is absent under 3 years of age, there is a rapid increase at 6 years of age. The incidence of nail-biting drops sharply after 18 years of age - Nail-biting is most commonly seen in excitable (hyperactive) children due to emotional unbalances (between 4 and 18 years) - Leads to crowding, rotation and attrition of lower anterior (notches) ### Abnormal Swallowing - Normal adult swallowing - Retained infantile swallowing - At certain age we shift from infantile swallowing to adult, but in this case no shift occurs - The muscles surrounding the teeth and lips are used to gain suction an infant than using the muscles of the throat which causes compression & contraction of the oral cavity and this lead to malocclusion - **N.B Other factors that can cause improper swallowing:** - Airway obstruction, such as enlarged adenoids or tonsils - Habitual sucking of the thumb or fingers (Thumb sucking push the tongue into an abnormal position when swallowing (Prevent tongue to be in the roof of the mouth). - **N.B. Bottle feeding may lead to futural problems in the position of the tongue during swallowing** ### Posture - Example: unilateral posterior crossbite due to abnormal body posture - Poor postural conditions is said to cause malocclusions, and it may accentuate an existent condition: - A steep-shouldered child, with the head hung so that the chin rests on the chest may create mandibular retrusion. - A child resting his head on his hand for periods of time each day, or sleeping on his arm, fist or pillow each night, may cause malocclusion. ### Mouth Breathing - Anything that interferes with respiratory physiology may affect the growth of the face. Mouth-breathers seem to a have a high incidence of malocclusions. - Mouth breathing is normally prevented by 3 sphincter mechanism: - Anterior sphincter: formed by the lips= lip seal - Intermediate sphincter: formed by the tongue and hard palate. - Posterio sphincter: formed between the soft palate and the dorsum of the tongue. ### Causes: - Partial nasal obstruction: due to - Deviated septum. - Narrow nasal passages. - Inflammatory reaction of nasal mucous membrane. - Allergic reaction of nasal mucosa. - Habitual Mouth Breathing: Habit, formed during the presence of one or more of the obstructive causes, and have persisted after the removal of the cause - True mouth breathing - Air hunger: in children with heart disease and as a normal behavior during exercise. - The typical mouth breathing syndrome is said to be characterized by (consequence of mouth breathing : (adenoid face) - Contracted maxillary arch - Protrusion of upper incisors (more labially).lip seal is lost - Hypertrophy of the lower lip→expressionless face - Hypotonic and short upper lip and frequently increased overbite. - The molar relationship may be normal or dis-occlusion (class II molar relation) - Increased overbite in some cases and anterior open bite in other cases - long face (as it increases the vertical growth of the face) - Examination: - If there is water vapor on a mirror or a glass slap that you have put infront of the nose - Ask the patient to take some water and close his mouth for some time, if he is mouth breather then he will not be able to keep his mouth closed for long time - How to manage ? - Elimination of the cause (such as removing the polyps) - Symptomatic treatment - Interception of the habit - If the habit continues even after removal of obstruction, then it should be corrected. - Correction can be done by: - Physical and lip exercise - Oral screen - Pre orthodontic trainer (T4K) ## Premature Loss of Deciduous Teeth 1. If deciduous incisors are prematurely lost: (upper or lower A&B) - Maxillary: usually cause no problems except esthetic and tongue thrust - Mandibular: crowding and arch collapse (decreased arch perimeter) - Front part of the lower jaw will resorb because of premature loss of deciduous incisors leading to a space loss in dental arch: there will be no enough space for the permanent incisors to erupt and align properly in the arch (crowding) 2. if deciduous canines are permanently lost (upper and lower C) - Crowded permanent canines due to late eruption of permanent canines and the longer period allowing shifting of adjacent teeth. - If unilateral loss of mandibular primary cuspid occurs: immediate extraction of the other primary cuspid should be done & lingual arch (space) maintainer - If not extracted, unilateral loss of mandibular primary canine will lead to: - midline shift - lingual tipping of incisors - increased overjet & overbite 3. Premature loss of deciduous first molar (upper or lower D) - (Usually NO crowding will appear but maybe distal canine shift occur preventing 4 from proper eruption) 4. Premature loss of deciduous second molar: (upper or lower E) - When E is lost early, 6 drifts mesially closing the space of 5, so 5 may erupt buccally or palatally or may fail to erupt 5. Premature loss of both upper and lower deciduous molars - may be a predisposing factor in the production of prenormal occlusion. (false /pseudo class III malocclusion) - N.B. If unilateral loss of E, dental midline shift occurs "in lower arch" - The most rapid losses in the arch perimeter are due to mesial tipping rotation of the first permanent molars (6) after removal of the second primary molars (E) - If (E) is lost before eruption of first permanent molars, then the first permanent molars will erupt more forward (mesial) with less rotation - NB: severe caries can cause the same effect. 6. Prolonged Retention of Deciduous Teeth - Causes: - Incomplete or unequal resorption of the roots. - Ankylosis of the deciduous teeth. (may be submerged) - Abscence of permanent teeth. (successors) - Abnormal path of the permanent teeth. - Endocrine disturbances e.g. Hypothyroidism. - Nutritional disturbance (as vitamin deficiencies as in vit A decreases) - some syndromes: eg cleidocranial dysostosis (disturbance in time table of eruption) - Delayed eruption of permanent teeth - Supernumerary tooth or odontoma - Retained deciduous - Eruption cyst - Tooth malformation as Dilacerations. - Ectopic eruption - Failure of eruption due to malfunction of the eruption mechanism. - Infection of the tooth germ. - Systemic disorders such as: # Diet # Metabolic # Genetic # Endocrine disturbance. - Loss of Permanent Teeth - Incisor Teeth: - Loss of upper incisors→1-spacing - Loss of lower incisors→1-midline shift - 2-diastema - 2- arch collapse (arch perimeter decreases) - Canine Teeth: - It has been said that the loss of an upper canine tooth may affect appearance of the face - Premolar Teeth: - The first premolar teeth are the teeth most frequently extracted to relieve incisor crowding and in the treatment of Angle's Class II & malocclusions. - 1st premolar is highly susceptible to caries and the second premolars. - First molars: - The permanent teeth most commonly lost through caries are the first permanent molars. - Effects of early loss of upper first molars: - The upper second molar tends to rotate forward rather than tilt. It rotates around its palatal root. (mesial drift of 7 less distal drift of 5 if unilateral midline shift) - Effects of early loss of lower first molar: - Mesial drift of 7 & Distal drift of 5 - If unilateral midline shift - Arch collapse & upper 6 over eruption (supra version) - Second Molars: - If lost may be replaced by third molars - Third Molars: - Early extraction to prevent impaction ## Trauma - Children are prone to accidents and the upper and lower deciduous or permanent incisors causing - Loss of deciduous teeth - Permanent incisors may be: - Dilacerated. - Displaced in the alveolus which may be fractured. - Fractured. - Lost completely. - Trauma to the T.M.J may result in damage and limitation of its movement. - Unilateral facial asymmetry - Bilateral bird face - Malunion that may follow fractured jaws may result in severe degree of malocclusion. ## Local pathological factors - There are rare and include: - Cysts or tumors in the jaws which may create malformation of one of the dental arches. - Scar tissues resulting from burns of the lips or cheeks that may contract & upset the balance of the craniofacial musculature. - Inflammatory conditions as "osteomyelitis" may cause damage of the condylar cartilage. The ascending ramus become short & the resulting malocclusion is usually severe. # Etiology of Malocclusion - General causes - Etiology of malocclusion is the study of the causes of malocclusion to diagnose a case and reach proper treatment plan - Skeletal malocclusion: - Can be treated early by Orthopedic treatment - Orthopedic treatment with appliances as: - Headgears - Twin block - Rapid maxillary expansion (as in skeletal crossbite) - Chin cups & face masks - Early intervention for growth //Orthopedic treatment is based on the principle that I modify growth so that it treats the skeletal problem without surgery, but only by using devices - For adults who have grown up, the orthopedic TTT is not effective because growth has stopped, so surgical intervention is necessary. - Dental malocclusion - Treating Growing or Adult patients whom have normal skeletal relation "skeletal class I" but have class I, II or III malocclusion (dental not skeletal) are treated by moving teeth (orthodontic treatment) whether adult is still growing and the problem is dental. The treatment will be by moving the teeth and not moving the basal bone - Malocclusion causes may be: - Hereditary or genetic problem - Environmental factors (external factor) - Genetic cause of mal occlusion is impossible to prevent - Environmental cause of mal occlusion can be prevented by control of habits & prevention of caries & PDL disease - Harris & Johnson: - They studied the influence of heredity on skeletal & dental variables in a longitudinal study and found that craniofacial parameters showed significant heritability - While the occlusal & arch parameters are affected minimally by genetic influence but increasing influence from environmental factors through postnatal growth ## Malocclusion causes: - General causes: - Evolution - Hereditary - Congenital - Environmental - Endocrinal - Pathological - Local causes ## General causes of malocclusion: - Evolutions - With evolution, the jaws become smaller (anterposteriorly) with a smaller number of teeth but not at the same rate. Lack of space results in impaction of wisdom teeth. - With evolution, less prognathism of the maxilla and mandible, with increased vertical height, leading to shorter dental arches that cannot accommodate all teeth leading to - Crowding - Impacted wisdom teeth located under second molars - Hereditary: - Tooth size, shape and number are inherited. - Inheritance of tooth size from one parent and jaw size from the other will cause malocclusion whether crowding or spacing. - Malocclusion may occur when: - Jaw is smaller than teeth size, leads to: crowding - Teeth size smaller than jaw, leads to: spacing - Jaw relation and skeletal pattern are inherited "Skeletal class I, II or III" - N.B. Some malocclusions are genetically determined e.g. Class II & ClassIII - For example: Class III of prognathic mandible is mainly heritable - Muscles "anatomy and activity→ Muscles mainly affect the bone and teeth - Congenital - A congenital defect is a disease or physical abnormality present at birth. - Cleft lip and palate - Cleido-cranial dysostosis - Pierre robin syndrome ### Cleft lip and palate - Could be of - Genetic origin - Intrauterine environmental problems.e.g., Smoking, alcohol Lack of folic acid, Drug administration (Aspirin, Dilantin, Corticosteroids) - Cleft lip: the philtrum or the medial nasal process failed to contact the maxillary process. - Cleft palate: the premaxillary process failed to contact the palatine processes of the maxilla, or the palatine processes of the maxilla failed to contact each other. - The cleft can be unilateral or bilateral, complete, or incomplete. - The presence of a palatal cleft may result in dental anomalies such as: - Enamel defects, hypodontia microdontia - Small & narrow maxilla leading to skeletal class III+posterior cross bite - Scarring resulting from the surgical repair of a cleft lip and palate results in restriction of mid-face growth - Complete bilateral cleft lip and palate lead to collapse of upper arch ### Cleidocranial dysostosis: cleido=clavicle - Is a rare congenital condition that affects teeth and bones, such as the skull, face, spine, collarbones, and legs. - It is characterized by: - Partial or complete absence of the clavicles - Delayed cranial suture closure - Supernumerary teeth - Retained deciduous and delayed eruption of permanent teeth lead to disturbance of eruption time table - Short and thin roots of permanent teeth - Maxillary retrusion with relative mandibular protrusion ### Pierre Robin Syndrome - It is characterized by: - Micrognathia - Cleft palate - High arched palate (deep palate) - Mandible is far back in the throat (retruded bird face)→glossoptosis - Repeated ear infection - Environmental - Prenatal - Rare - Can be minimal e.g., 1-amniotic lesions and fibroids, or more pronounced e.g., German measles - Intrauterine molding in uterus example prenatal fetus hand is pressing on maxilla or mandible (can result in maxillary deficiency)→retrognathic - Trauma or infection as German measles may lead to clef palate - The role of prenatal influences on occlusion is usually minimal (very small) - Postnatal: - Injury at birth: Obstetric forceps can lead to irreversible damage to TMJ. (which influence growth of mandible) - Accidents e.g., mandibular and condylar fractures. Following condylar fracture, asymmetric growth deficiency may take place, with the injured side lagging behind. - Burn scars cause excessive pressure on growing structures. - Nutritional deficiency: - Vitamin D: lead to (Rickets disease) - A deficiency of vitamin D may lead to rickets in children which is characterized by softening of the bones brought on by extreme calcium loss. - Muscles are hyper-irritable causing pressure on the softer bones (due to calcium loss) resulting in: - Malformed mandibular body - Obtuse gonial angle - Open bite - Decreased forward growth of facial bones (anteroposterior)→retrognathic jaws - dental deformities (vit D decrease leads to 3D) - Delayed formation of teeth - Disturbed calcification of teeth and poor enamel formation - Dental caries (increase incidence of cavities in teeth) - Vitamin A: - In a developing tooth with deficient vitamin A, - odontogenic epithelium fails to undergo normal histodifferentiation or morphodifferentiation leading to abnormal shape of teeth and enamel hypoplasia. - Since the forming cells are disturbed, they are not functioning properly. Enamel matrix is poorly defined so that calcification is disturbed & Enamel hypoplasia results. - Eruption rate is retarded, in prolonged deficiencies eruption ceases. - Alveolar bone is retarded in its rate of formation. Its formation is also damaged and slow - Gingival epithelium becomes hyperplastic: may cause periodontal diseases "tooth mobility and spacing" periodontitis - Vitamin C: - Vitamin C is important for the formation of intercellular ground substance in bone, dentin, and other connective tissues. - Its deficiency results in scurvy. - Vit c deficiency leads to atrophy and dis-organization of the odontoblasts resulting in production of irregular laid down dentin with few irregularly arranged tubules 4- Interdental and gingival margin is red with bright shiny smooth surface that can ulcerate and bleed. - In severe cases of scurvy, hemorrhage and swelling of PDL membranes occur followed by loss of bone and loosening of teeth. - Smoking depletes vitamin C in the body. So, smokers need extra amounts of vitamin C. - Endocrinal - Hypothyroidism (Cretinism) - Hypopituitarism (Pituitary Dwarfism) - hyperpituitarism (acromegaly/gigantism) - Hypothyroidism (Cretinism): - Cretinism is hypothyroidism in children. It occurs due to decreased production of thyroid hormone. - Failure of thyroid hormone secretion causes: - Abnormal resorption pattern - Retained deciduous teeth and deflected permanent teeth - Delayed eruption pattern - Tongue enlargement (macroglossia)→leads to proclination of teeth - Gingival disturbances - Those who have hypothyroidism since infancy or birth usually do not grow like others. - The body is short and stocky. - Mental retardation is likely. - Hypopituitarism (Pituitary Dwarfism): - Pituitary dwarfism is caused by decreased production of Growth Hormone. It results in: - Proportional small jaws - Delayed eruption of permanent teeth and retained deciduous teeth - Root formation and apical foramen closure are delayed or incomplete - Pituitary dwarfism - Hyperpituitarism (Acromegaly): - Acromegaly is caused by excessive production of Growth Hormone. It results in: - Large mandible with protracted chin - Generalized overgrowth of the skeletal and soft tissues - Spacing - Hyperpituitarism leads to Gigantism or Acromegaly - Acromegaly: characterized by enlargement of the bones of the face & fingers as the person ages - Gigantism affects the height of an individual, produces very tall body, as basketball - N.B. Normally: Quantity of Growth Hormone is greatest during childhood & adolescence - GH promotes bone & muscle growth. But if: - Too little growth hormone during childhood → Pituitary dwarfism - Too much growth hormone during childhood → Giants - Too much growth hormone in adults → Acromegaly - Hypo-Thyroidism - Decreased secretion of thyroid hormones, leads to # Cretinism - Abnormal resorption pattern of deciduous teeth roots - Retained deciduous teeth & deflected permanents. Delayed eruption pattern - Gingival disturbances - Short and stocky body - Mental retardation - Hypo-pituitarism - Decreased production of growth hormone, leads to: # Pituitary dwarf - small jaws - Delayed permanent teeth eruption and retained deciduous teeth - Incomplete root formation & delayed apical foramen closure - Short but normal body proportions - Mentally normal - Hyper-pituitarism - Excessive production of growth hormone leads to: # Acromegaly or Gigantism - Large mandible with protracted chin - Accelerated eruption of teeth - discolored and have an irregular surface. - Pathological: - Febrile diseases may upset the dentional developmental timetable during infancy and early childhood. - High fever tampers with the calcification process of the enamel in young teeth. This causes the enamel to be defective in structure. - The rough patches on the enamel are more susceptible to decay. - Muscle diseases e.g., Muscular dystrophy or cerebral palsy.