Dr kazem dalaie
Assistant professor of orthodontics
Shahidbeheshti university of medical sciences-dental school-orthodontic department
Generally, the permanent first molars (PFM) are not appropriate teeth for extraction in orthodontic context.some reasons are low effectiveness in anterior decrowding ,drifting of adjacent teeth,overeruption of opposite teeth and midlines deviations.on the other hand the first molars are the most susceptible tooth to decay and enamel hypomineralized defects in the oral cavity and During the mixed-dentition stage of dental development, dentists may be more exposed to first permanent molars with poor long-term prognosis and have an only exraction option.
The aim of current study is presentation of factors can influence on extaction of PFM with poor prognosis including occlusional and developmental factors.These factors have been discussed by case series. In occlusional factors from orthodontic view : severity of crowding,molar relationships,overjet and overbite, midlines deviation,skeletal relationship and soft tissue status have been considered .in developmental factors from dental developmental view:developmental stage of second permanent molars (SFM)(according to Demirjian stage), Presence or absence of third molars ,second permanent molars angulation,dental age of SFM ,second premolar position and.. have been considered.some contraindication of PFM exractions are mentioned as well.
When planning extraction of PFMs with poor prognosis it is important to consider whether future active appliance orthodontic treatment will be necessary.