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Etiology
of
Malocclusion DEPARTMENT OF ORTHODONTICS
SUBHARTI DENTAL COLLEGE
SWAMI VIVEKANAND SUBHARTI UNIVERSIT Y
Dr Kumar Amit, Subharti
Dental College, SVSU
Presented By:
Dr Kumar Amit
identify malocclusion
Dr Kumar Amit, Subharti
Dental College, SVSU
Introduction :
Malocclusions may involve four tissue systems
m Teeth
m Bones
m Muscles
m Nerves
Dr Kumar Amit, Subharti
Dental College, SVSU
Another way to classify malocclusion is to divide them into three groups
m Skeletal dysplasias
m Dental dysplasias
m Skeleto dental dysplasias
Dr Kumar Amit, Subharti
Dental College, SVSU
Etiologic factors
Inherited pattern of malocclusion : polygenic
Exogenic influence : - systemic or localized
- static or functional
Dr Kumar Amit, Subharti
Dental College, SVSU
Interaction between hereditary and
environmental factors
Dr Kumar Amit, Subharti
Dental College, SVSU
Causes of malocclusion
Dr Kumar Amit, Subharti
Dental College, SVSU
Dr Kumar Amit, Subharti
Dental College, SVSU
Classification of etiologic
factors of malocclusion
ACCORDING TO MOYERS
Heredity
T Neuro muscular system
T Bone
T Teeth
T Soft parts (other than nerve and muscle)
Developmental defects of unknown origin
Trauma
T Prenatal trauma and birth injuries.
T Post natal trauma.
Dr Kumar Amit, Subharti
Dental College, SVSU
Physical agents T Pre natal
T Post natal
Habits TThumb and finger sucking, tongue
thrusting, lip biting etc
Disease T Systemic diseases
T Endocrine diseases
T Local diseases
Malnutrition Dr Kumar Amit, Subharti
Dental College, SVSU
According to Salzmann
Salzmann’s diagrammatic representation of the etiologic factors in
malocclusion embodies prenatal and post natal factors.
It clearly shows the genetic, differentiative and congenital factors
that make up the prenatal elements of causation, which can
influence one or all of the postnatal components- developmental,
functional, environmental. Dr Kumar Amit, Subharti
Dental College, SVSU
According to Graber
General Factors
Heredity (The inherited pattern)
Congenital Defects
T Cleft palate
T Torticollis
T Cleidocranial dysostosis
T Cerebral palsy
T Syphilis etc.
Dr Kumar Amit, Subharti
Dental College, SVSU
Environment
T Pre natal
Q Trauma
Q Maternal diet
Q Maternal metabolism
Q German measles etc.
T Post natal birth injury
Q Cerebral palsy
Q TMJ injury etc.
Dr Kumar Amit, Subharti
Dental College, SVSU
Pre disposing metabolic climate and disease
T endocrine imbalance
T metabolic disturbances
T infectious diseases
Dietary problems
T nutritional deficiency
Dr Kumar Amit, Subharti
Dental College, SVSU
Abnormal pressure habits and functional aberrations
Abnormal suckling
Forward mandibular posture
Non physiologic nursing
Excessive buccal pressures
Thumb and finger sucking
Tongue thrust and tongue sucking
Lip and nail biting
Abnormal swallowing habits
(improper deglutition)
Speech defects
Dr Kumar Amit, Subharti
Dental College, SVSU
Respiratory abnormalities
(mouth breathing)
Tonsils and adenoids (compensatory tongue position)
Psychogenic tics and Bruxism
Posture
Trauma and Accidents
Dr Kumar Amit, Subharti
Dental College, SVSU
Local factors
Anomalies of number
T Supernumerary teeth
T Missing teeth
Q Congenital absence or loss due to
accidents, caries etc
Anomalies of tooth size
Anomalies of tooth shape
Abnormal labial frenum, mucosal barriers
Dr Kumar Amit, Subharti
Dental College, SVSU
Premature loss
Prolonged retention
Delayed eruption of permanent teeth
Abnormal eruptive path
Ankylosis
Dental caries
Improper dental restorations
Dr Kumar Amit, Subharti
Dental College, SVSU
ACCORDING TO PROFFIT
Specific causes
T Disturbances in embryologic development
(teratogens)
T Skeletal growth disturbances
Q Intrauterine molding
Q Birth trauma to mandible
Q Childhood fractures or the jaw
T Muscle dysfunction
Dr Kumar Amit, Subharti
Dental College, SVSU
TAcromegaly and hemi mandibular hyper trophy
TDisturbances of dental development
Q Congenitally missing teeth
Q Malformed and supernumerary teeth
Q Interferance with eruption
Q Ectopic eruption
Q Early loss of primary teeth
Q Traumatic displacement of teeth
Dr Kumar Amit, Subharti
Dental College, SVSU
Genetic influences
Environmental influences
T Equilibrium theory and development of dental occlusion
T Functional infuence on dento facial development.
Dr Kumar Amit, Subharti
Dental College, SVSU
General factors
Heredity
A child may have facial features that markedly resemble those of his father or mother, or the net result may be a combination of features from each parent. It is also to be noted that, a single gene is not responsible for a particular malocclusion and it may be due to the combined action of different types of Genes
Heredity could be considered significant in determining the following characteristics
Dr Kumar Amit, Subharti
Dental College, SVSU
T Tooth size
T Width and length of arch
T Height of palate
T Crowding and spacing of teeth
T Overjet
T Position and conformation of perioral musculature to
tongue size and shape
T Soft tissue peculiarities
T Facial asymmetries
T Macorgnathia and micrognathia
T Macrodontia an microdontia
Dr Kumar Amit, Subharti
Dental College, SVSU
TOligodontia and anodontia
T Tooth shape variations
(peg laterals, Carabellis cusps, mamelons etc)
TCleft palate and hare lip
TDiastemas
TDeep bite
TRotation of teeth
TMandibular retrusion
TMandibular prognathism
Dr Kumar Amit, Subharti
Dental College, SVSU
Congenital defects
Cleft lip and palate
Congenital defects life cleft lip and palate separately or in combination are among the most frequent congenital deformities of mankind. It is not often possible for the dentist to compensate for residual post surgical abnormalities. In a unilateral cleft, the teeth or one side are usually in lingual cross bite with the opposing lower teeth. Many times the premaxilla is displaced anteriorly, or, because of the tightly repaired lip, the whole pre maxillary structure is forced lingually. The maxillary incisors in this type are badly malposed with bizarre axial inclinations. In the area of cleft, teeth are often jumbled. Maxillary lateral incisors may be missing, atypical in shape or ‘twinned’ Dr Kumar Amit, Subharti
Dental College, SVSU
Cerebral palsy
Paralysis or lack of muscular co-ordination due to an intra cranial lesion
Complete lack of motor control resulting in abnormal muscular function in masticaction, deglutition, speech and respiration.
Abnormal pressure habits lead to malocclusion Dr Kumar Amit, Subharti
Dental College, SVSU
Torticollis
Shortening of the sternocleido mastoid muscle causing profound
changes in the bony morphology of the cranium and the face
Characterised by “wry neck”
Bizarre facial asymmetries and uncorrectable malocclusions if not
treated early
Dr Kumar Amit, Subharti
Dental College, SVSU
Cleidocranial dysostosis
Maxillary retrusion and possible mandibular protrusion
Retained deciduous teeth
Retarded eruption of permanent teeth
Short and thin permanent teeth roots
Super numerary teeth
Dr Kumar Amit, Subharti
Dental College, SVSU
Congenital Syphilis
Abnormally shaped teeth
Dr Kumar Amit, Subharti
Dental College, SVSU
Pre natal
Post natal
Environment
Dr Kumar Amit, Subharti
Dental College, SVSU
Pre natal
Teratogens: Chemical and other agents capable of producing
embryologic defects if given at critical time are called teratogens
Aminopterin
Aspirin
Cigarette smoke (hypoxia)
Cytomegalovirus
Anencephaly
Cleft lip and palate
Cleft lip and palate
Microcephaly, hydrocephaly,
microphthalmia
Dilantin
Ethyl alcohol
6-Mercaptopurine
13-cis Rentinoic acid
(Accutane)
Cleft lip and palate
Central mid-face deficiency
Cleft Palate
Retinoic acid syndrome: malformations
virtually same as hemifacial microsomia,
Treacher Collins syndrome
Rubella virus
Thalidomide
Microphthalmia, cataracts, deafness
Malformations similar to hemifacial
microsomia, Treacher Collins syndrome
Toxoplasma Microcephaly, hydrocephaly,
microphthalmia
X-radiation
Valium
Vitamin D excess
Microcephaly
Cleft and palate
Premature suture closure Dr Kumar Amit, Subharti
Dental College, SVSU
Intrauterine molding
Pressure against the developing face prenatally can lead to distortion of rapidly growing areas. Eg: an arm is pressed across the face in utero resulting in severe maxillary deficiency.
Other factors that may affect are trauma, maternal diet, maternal metabolism and German measles
Dr Kumar Amit, Subharti Dental
College, SVSU
Birth trauma
In some difficult births use of forceps to the head to assist in delivary might damage either or both TMJ. Heavy pressure in the area of TMJ could cause internal haemorrhage, loss of tissue and a subsequent under development of the mandible
Childhood fractures: Falls that produce condylar fractures may cause marked facial asymmetries
Extensive scar tissue, from a burn may also produce malocclusions
Post natal
Dr Kumar Amit, Subharti Dental College,
SVSU
Some specific endocrinologic diseases may be potent makers of malocclusion. Diseases with a paralytic effect, such as poleomyelitis are capable of producing malocclusions.
Disease with muscle malfunction, such as muscular dystrophy and cerebral palsy also have deforming effects on dental arch
Pre disposing metabolic climate and
diseases
Dr Kumar Amit, Subharti
Dental College, SVSU
Hypothyroidism
Abnormal resorption patterns
Delayed eruption pattern
Gingival disturbances
Retained deciduous teeth
Dr Kumar Amit, Subharti
Dental College, SVSU
Acromegaly
Which is caused by an anterior pituitary
tumor that secrete excess amounts of GH, excessive
growth of mandible may occur, creating a skeletal
class III malocclusion in adult life. Also multiple root
resorption may be found.
Dr Kumar Amit, Subharti
Dental College, SVSU
Nutritional deficiency
Disturbances such as rickets, scurvy and berry-
berry can produce severe malocclusions. Main problem is
upsetting of the dental developmental time tables. The
resultant premature loss, prolonged retention, poor tissue health
and abnormal eruptive paths lead to malocclusion
Dr Kumar Amit, Subharti
Dental College, SVSU
Non nutritive sucking habits, Includes all
sucking habits
T Thumb sucking
T Finger sucking
T Pacifiers etc.
Abnormal pressure habits and functional
aberrations
Dr Kumar Amit, Subharti
Dental College, SVSU
Dento facial changes associated with prolonged non nutritive sucking habits are
T Increased proclination of upper incisors
T Increased maxillary arch length
T Increased clinical crown length of max incisiors
T Increased atypical root resorption in primary central incisors
Dr Kumar Amit, Subharti
Dental College, SVSU
T Increased retroclination of mandibular incisors
T Increased overjet
T Decreased over bite
T Increased unilateral and bilateral class II occlusion
T Increased lip incompetence
T Tongue thrust
T Speech defects, especially lisping
Dr Kumar Amit, Subharti
Dental College, SVSU
Lip biting
T Involves the lower lip which is turned inwards and pressure is exerted on the lingual surfaces of maxillary anteriors
T Proclined upper anteriors and retroclined lower anteriors
T Hyper trophic and redundant lower lip
T Cracking of lips
Lip habits
Dr Kumar Amit, Subharti
Dental College, SVSU
Nail biting
Does not produce gross malocclusion. But
minor local tooth irregularities like
T Rotation
T Wear of incisal edge
T Minor crowding.
Dr Kumar Amit, Subharti
Dental College, SVSU
Tongue thrust Defined as a condition in which the tongue makes contact with
any teeth anterior to the molars during swallowing
It has to be remembered at this time that there is a controversy regarding Tongue thrust as an etiologic factor of anterior open bite. According to Graber and Moyers, Tongue thrust definitely leads to anterior open bite. Proffit contradicts this fully and according to him, it is an already existing anterior open bite that leads to Tongue thrusting habit
T Proclination of anterior teeth
TAnterior open bite
T Bimaxillary protrusion
T Posterior open bite in case of
lateral Tongue thrust
T Posterior cross bite
Dr Kumar Amit, Subharti
Dental College, SVSU
Mouth breathing
Mouth breathing can result in altered jaw and tongue posture which could alter the oro-facial equilibrium there by leading to malocclusion
T Long and narrow face
T Short and flaccid upper lip.
T Contracted upper arch with possibility of
posterior cross bite
T Increased overjet as a result of flaring of the incisors.
T Dryness of the mouth predisposes to caries.
T Anterior open bite
Dr Kumar Amit, Subharti
Dental College, SVSU
Bruxism
Grinding of teeth for non functional purposes
T Occlusal wear facets
T Fractures of teeth and restorations
T Mobility of teeth.
T Tenderness and hypertrophy of masticatory muscles
T TMJ pain
Dr Kumar Amit, Subharti
Dental College, SVSU
Tongue size as well as function is an important
consideration. Aglossia can result in narrowing of the upper dental arch with severely malpositioned teeth and crowding. Where as Macroglossia can lead to widening of dental arches, spacing and open bite.
Dr Kumar Amit, Subharti
Dental College, SVSU
Anomalies in number of teeth
T Super numerary teeth
T Missing teeth
Local factors
Dr Kumar Amit, Subharti
Dental College, SVSU
Super numerary teeth
The presence of extra tooth obviously has great potential to disrupt normal occlusal development. Early intervention and to remove it is usually required to obtain reasonable alignment and occlusal relationships. Most common-mesiodens.
Also lateral incisors, extra premolars, fourth molars multiple super numerary teeth are found in cleidocranial dysplasia and other congenital deformities like cleft lip and cleft palate
Dr Kumar Amit, Subharti
Dental College, SVSU
Missing teeth Congenital absence
Due to accidents / caries
Order of frequency
T Max and mandibular 3rd molars
T Max laterals
T Mandibular 2rd premolars
T Mandibular incisors
T Maxillary second premolars
Anodontia–complete absence
Oligodontia–congenital absence of many, but not all teeth
Hypodontia – absence of only a few teeth
Dr Kumar Amit, Subharti
Dental College, SVSU
Quite frequently it has been noted that, one maxillary lateral incisor will be of normal size and configuration while the other is small. Anomalies of size are relatively frequent in the mandibular pre molar area
Anomalies of tooth size
Dr Kumar Amit, Subharti
Dental College, SVSU
Anomalies of Tooth Shape
Most frequent – “Peg Lateral”
Leads to excessive spacing. Anomalies of shape occur as a result of developmental defects like amelogenesis imperfecta, hypoplasia, Gemination, Dens in Dente, Odontomas, Fusions, Congenital syphilitic aberations such as Hutchinson’s incisors and mulberry molars.
Dr Kumar Amit, Subharti
Dental College, SVSU
Abnormal labial Frenum
If the frenum is thick, it prevents the closure of diastema (which is normal during mixed dentition prior to the eruption of canines)
In these cases a frenectomy is indicated
Dr Kumar Amit, Subharti
Dental College, SVSU
Premature loss of deciduous teeth
The early loss of permanent teeth should be considered as a “Malocclusion Maker”
Deciduous teeth not only serve as organs of mastication, but as space savers for permanent teeth. Loss of a deciduous 2nd molar will lead to mesial drift of the 1st permanent molar and blocking of erupting 2nd premolars. In this cases appropriate space maintainers should be given
Dr Kumar Amit, Subharti
Dental College, SVSU
Prolonged retention and abnormal
resorption of deciduous teeth
If the roots of the deciduous teeth are not resorbed properly, uniformly or on schedule, the permanent successors may be either withheld from eruption, or they may be deflected into malposition
Dr Kumar Amit, Subharti
Dental College, SVSU
Delayed eruption of Permanent teeth
Endocrine disorders like hypothyroidism
Presence of supernumerary teeth or
deciduous root
Mucosal or Bony barrier
Dr Kumar Amit, Subharti
Dental College, SVSU
This is usually a secondary manifestation of a primary disturbance
T Severe crowding
T Super numerary tooth
T Retained deciduous tooth / root fragment
T Bony barrier
T Dentigerous cysts
Another form of abnormal eruption is referred as ectopic eruption. Most common form is a permanent tooth erupting through the alveolar process causing resorption on a contiguous deciduous tooth or permanent teeth , rather than its predecessor. Eg; maxillary first molar, causing resorption of maxillary deciduous second molar.
Abnormal eruptive path
Dr Kumar Amit, Subharti
Dental College, SVSU
Ankylosis
Ankylosis or partial ankylosis occurs relatively frequently during 6-12 year age period. Ankylosed deciduous teeth should be identified and treated by removal or building up or surgical subluxation along with space maintainers.
Permanent teeth can also be found to be ankylosed can be due to
T Accidents / trauma
T Congenital diseases like cleidocranial dysostosis
Dr Kumar Amit, Subharti
Dental College, SVSU
Dental caries
Dental caries should be considered as one of the local factors causing mal occlusion. Caries which leads to premature loss of a deciduous or permanent tooth may cause drifting, axial inclination, over eruption, bone loss etc.
Dr Kumar Amit, Subharti
Dental College, SVSU
Improper dental restorations
Silver mercury alloy restorations have a tendency to “flow” under pressure. Large proximal restorations change gradually under the assault of occlusal forces, and arch length is increased. This may result in the creation of broken contacts, rotations, crossbite conditions and functional prematurities. Lack of anatomic detail in restoration of cuspal areas of a tooth can permit elongation of opposing tooth.
Loose contacts also leads to food packing, teeth tend to move apart and also leads to bone loss
Dr Kumar Amit, Subharti
Dental College, SVSU
Knowledge about the various etiological factors of malocclusion will help us to plan the various interceptive and preventive orthodontic procedures.
It also helps in eliminating the etiological factor if it is of a environmental type.
The recognition and reporting of a malocclusion or a condition that could lead to a malocclusion is the most important service that a dentist can provide to his patients. Malocclusion has an important impact on the function and esthetics of the entire dentition. In fact, malocclusion has a detrimental effect on the self esteem of many children, adolescent and adult. If a malocclusion is not recognized by either the dentist or the patient, it cannot be assessed and treated
A sound knowledge about the various factors that lead to malocclusion, will definitely help is to render excellent treatment for our patients with good retention and stability
Conclusion
Dr Kumar Amit, Subharti
Dental College, SVSU
Dr Kumar Amit, Subharti
Dental College, SVSU
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