Etiology Of Malocclusion
Question 1. Define local etiological factors of malocclusion.
Or
Write a short note on local factors in the etiology of malocclusion.
Answer.
Local Etiological Factors of Malocclusion
Anomalies in Teeth Number
- The presence of extra teeth or absence of teeth leads to malocclusion.
- Supernumerary teeth occupy more space in the arch and lead to crowding, rotation, or ectopic eruption of other adjacent teeth, e.g. mesiodens and paramolars.
- Extra teeth which resemble normal teeth are known as supplemental teeth.
- The absence of teeth causes spacing and migration, axial indication, and supra eruption of other teeth.
Read And Learn More: Orthodontics Question And Answers
Anomalies in Tooth Size
- Macrodontia results in crowding.
- Microdontia results in spacing.
- Fusion between two adjacent teeth or between a supernumerary tooth and a normal tooth may predispose to malocclusion.
Anomalies of Tooth Shape
- Abnormally shaped teeth lead to malocclusion.
- Peg laterals lead to spacing.
- Large cingulum of maxillary incisors leads to deep bite or close bite.
- Additional cusp on the premolar or mulberry molar causes occlusal prematurities.
- Dilacerated teeth often fail to erupt to correct occlusion lines.
- Fusion and gemination lead to crowding
Abnormal Labial Frenum
- Abnormalities in the labial frenum like high attachment leads to midline diastema.
- Thick mucosal tissue that covers erupting teeth acts as barrier to path of eruption and results in soft tissue impaction.
Premature Loss of Deciduous Teeth
- It refers to loss of a tooth before its permanent successor is sufficently advanced in development and eruption to occupy its place.
- Leads to migration, axial inclination and supraeruption of other teeth and prevent the eruption of permanent successors.
Prolonged Retention of Deciduous Teeth
- Prolonged retention of anterior deciduous teeth leads to lingual or palatal eruption of their permanent successors.
- Prolonged retention of posterior deciduous teeth leads to an eruption of permanent teeth either buccally or lingually or may remain impacted.
Delayed Eruption of Permanent Teeth
It is caused due to congenital absence of permanent tooth, supernumerary tooth blocking eruption of permanent tooth, endocrinal disorders such as hypothyroidism etc.
Abnormal Eruption Path
Ectopic eruption leads to malocclusion
Ectopic eruption may occur due to arch length defiiency, presence of supernumerary teeth, retained root fragment or formation of a bony barrier.
Trauma to Teeth
- Trauma to the deciduous teeth can lead to displacement of permanent teeth, defective enamel formation or dilacerated roots.
- Trauma to permanent teeth can result in ankylosis, nonvital tooth and displacement of tooth.
Dental Caries
It leads to premature loss of deciduous or permanent teeth which causes migration of contiguous teeth and leads to abnormal axial inclination and supraeruption of opposing teeth.
Improper Dental Restoration
- Over contoured occlusal restoration causes premature contacts leading to functional shif of the mandible during jaw closure.
- Under contoured restoration result in supraeruption of opposing dentition.
- Proximal restoration if under contoured causes loss of arch length and food lodgement while over contoured restorations take more space which causes irregularity of dentition.
Question 2. Write short note on mesiodens.
Answer. It is a supernumerary tooth.
- It is located at or near the midline in the incisal region of maxilla between central incisors.
- It may occur singly or paired, erupted or impacted or even inverted.
- It is a small tooth with cone shaped crown and short root.
- It may cause retarded eruption, displacement or resorption of adjacent root. It frequently causes improper alignment.
- Unerupted mesiodens is one of the causes of midline spacing.
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