 everybody. The topic for today is serial extraction. So serial extraction is basically an interceptive orthodontic procedure that is it is initiated in the early mixed antition period. This is the period where you can anticipate any potential irregularities in dental facial complex that can further lead to established malocclusion that will require comprehensive orthodontic treatment. So you recognize this in an early stage when there are signs of crowding, severe crowding in the patient and that is when you it is intercepted. So it is an interceptive orthodontic procedure. Now let us see the definition. There are two one by the gun given by the well and one by profit. Now the key word here is the correctly timed and planned removal because you do it at proper timings only. So serial extraction is the correctly timed planned removal of certain deciduous and permanent teeth in mixed antition with dental alveolar disproportion in order to alleviate crowding of incisor teeth. The next definition is serial extraction is the timed extraction of primary and ultimately permanent teeth to relieve severe crowding. Now let us have a look at the history. So patient was the first to point out extraction to improve extraction as a therapeutic procedure to improve the irregular alignment and crowding of teeth. Then Jelgrin in 1929 first used the term serial extraction to describe a procedure where some deciduous teeth followed by permanent teeth were extracted to guide the rest of the teeth into normal occlusions. Then Nans in the 1940s popularized this technique in the USA and termed it planned and progressive extraction and hordes referred to the procedure as guidance of eruption. Now there are three main factors that are to be considered as the rational behind serial extraction procedure. First is the arch length tooth material discrepancy. Now what is one of the most important causes of crowding? This is when there is excess tooth material that is present compared to the available arch length. So there is a discrepancy in arch length and tooth material. So this is one of the main factors to be considered. Next comes physiologic tooth movement. This is teeth have a tendency to move into the empty spaces that is available for it. It moves in that direction. It drifts in the direction. So when you extract certain specific deciduous teeth this allows for the proper eruption direction of the erupting permanent teeth. Then comes the normal dental skeleton and profile development. That is serial extraction is indicated only when there are normal skeletodental relationships and is any other cases not an ideal case for serial extraction. Now what are the indications? What are the ideal cases for serial extraction? Class 1 molecular occlusions are the ideal cases a true relatively severe hereditary tooth size or jaw size discrepancy if it is present. Makes a good case for serial extraction or if there is a mesial step mixed dentition which show signs of developing into class 1 permanent relationship eventually when there is minimum over jet and over bite. If the facial pattern is orthognatic or with slight alveodental protrusion. So how do you make out if there is hereditary crowding present? So these are the signs that you look out for which would make the patient an ideal case for serial extraction procedure. That is if there is maxillary mandibular dental alveolar protrusion without any inter proximal spacing. If there are crowded mandibular incisors if there is a midline displacement of permanent mandibular incisors resulting in the premature exfoliation of primary canine on the crowded side. If there is a crescent shaped area indicating external root resorption on the mesial aspect of primary canines which is again caused by crowding due to permanent lateral incisors. If there is bilateral mandibular primary canine exfoliation resulting in lingual uprighting of permanent incisors that is there is a lingual inclination of the incisor. If there is a spraying or if there is a flaring of permanent maxillary or mandibular incisor caused by crowded malposition of unadrupted permanent canines due to the pressure of the canines that cannot erupt and if there is gingival recession on the mandibular incisors. So these are the signs of hereditary crowding or because of arch length tooth material discrepancy. If there is a prominent bulging in vestibule if there is a discrepancy in size of primary and permanent teeth this reduces the leeway space and eventually leads to crowding. If there is an ectopic eruption of permanent maxillary first molar or impaction of permanent mandibular second molars. Now other than these hereditary causes hereditary jaw size discrepancy causes there can be other causes also such as trauma, itrogenic causes, transposition of teeth, rotation of teeth, ankylosis of primary teeth, premature loss of primary teeth which can lead to drifting of the permanent teeth into these empty spaces, prolonged retention of lower second primary molars that is over retained deciduous teeth, inter proximal under stored caries this can again lead to loss in the arch length, abnormal exfoliation sequence and altered emergent sequence all these can also lead to crowding. Now what are the contraindications? Class 2 and 3 malocclusion cases with skeletal abnormalities are not an ideal case for serial extraction. If there is space dentition serial extraction is strictly not indicated anodontia or oligodontia. If there is open bite and deep bite because serial extraction can worsen the condition of deep bite, if there is midline diastema, cleft lip plalate, mild to moderate crowding which does not require serial extraction but can be corrected from other procedures such as proximal stripping for example, dilacirated teeth. If there are extensive caries for restoration or if there is class 1 malocclusion but with very minimal space deficiency serial extraction is not required and again if there is a mild disproportion. So all these cases are not ideal for serial extraction so it is important to keep these in mind. Now what are the advantages of serial extraction as a treatment procedure? The main thing is that this treatment is more physiology because it is all physiologic you just extract the deciduous teeth or if required permanent teeth at certain times and you just allow the erupting permanent teeth to be guided into proper space you are not using any other external force. So it is a very physiologic mode of treatment and also because this is an interceptive orthodontic procedure it can reduce the psychological trauma associated with malocclusion in if there is if it can lead to establish malocclusion in later stages of the life by intercepting it in the beginning much before you can avoid the psychological trauma caused by malocclusion. It eliminates the duration of multi-banded fixed treatment that is comprehensive orthodontic treatment eventually. Better oral hygiene is possible because it reduces the crowding then pedodontal health that is health of investing tissue is preserved and even if orthodontic treatment is done after serial extraction the retention period that is required once the treatment is completed is much lesser comparatively and more stable results are achieved as the tooth material and arch length are in harmony now. However the disadvantages are that as we saw it cannot be universally applied to all patients. Treatment time is prolonged as the treatment goes on for 2 to 3 years as we saw in the definition itself the timing is very important and it goes it can go on for a very long period of time which means that patient cooperation is extremely necessary to report on the proper time as and when required. As the extraction spaces are created that close gradually the patient has a tendency to to protrude the tongue into those empty extraction spaces that have been developed so it can lead to the developing of the habit of tongue thrusting. Then extraction of buckle teeth can result in deepening of the bite if the procedure is not carried out properly there is a risk of arch length reduction if it is not timed properly then the arch length can be further reduced because of the mesial migration of the teeth into the empty extraction spaces and there can be a result in space that exists between the canine and second primolar. Now before starting the procedure before making the diagnosis how do you determine that this case is ideal for serial extraction. This is through a complete set of diagnostic records which includes panoramic radiographs, cephalometric radiographs, CBCT, oriented facial photographs, study models and intraoral photographs. Now dental radiographs must be taken for the following reason for documentation purposes. For detection of any congenital absences of teeth, supernumerary teeth, any root resorption signs that is that is that can be evident of crowding pattern to calculate the total space analysis and assessment of trauma to teeth if any and to evaluate the size and position of the third molar. Cephalometric radiographs are required to evaluate the craniofacial dental relationships before treatment. You evaluate the skeletodental positions and the treatment should be gone ahead with only if the skeletodental relationships are normal. It also helps in assessment of soft tissue matrix prediction of growth and development as a basis for monitoring of skeletodental relationships during treatment and for detection of pathology conditions before and after treatment. Facial photographs are required for evaluation and documentation of craniofacial relationships again for assessment of soft tissue profile and for occlusion curve analysis and to monitoring to monitor treatment progress at each stage of the treatment. Study models are required to calculate total space analysis to assess and document dental anatomy in the intercalciation arch form. All the model analysis is done using the study models, the model analysis to determine the amount of crowding that is the amount of discrepancy in the tooth material and jaw size which is an extremely important factor in determining whether the patient is an ideal candidate for serial extraction. Now how do you know what is the proper timing for the extraction of the particular teeth? So 3 factors need to be considered. The effect of extraction of the primary tooth on the eruption of its primary successor, the amount of root formation at the time of emergence, the length of time for the attainment of various stages of root development. Keeping these 3 factors in mind you decide on what time the extraction should be done. Now there have been various procedures of serial extraction that have been proposed through the years. Some of the important ones will be discussed here. First is Devel's method. So this is commenced at around 8 to 9 years of age that is mixed dentition period. So here first the deciduous canines are extracted that is C. Then you give a gap of 1 year. Then once the canines are extracted after 1 year deciduous first molars are extracted that is D. Now once the D is extracted this accelerates the eruption of the first premolar into its space. So once that is accelerated the extraction of erupting first premolar is then done. So after all this is done it allows for the proper space for the canines, permanent canines to erupt in proper alignment. So the sequence to remember for Devel's method will be C D4. Then comes Tweet's method. This is also commenced at around 8 years of age. Here first all the first deciduous molars are extracted. Unlike Devel's method canines, the deciduous canines here are allowed to remain in position so that the eruption of permanent canines can be delayed. Now after 4 to 10 months of extracting all the first deciduous molars that is D's then extract all 4 erupting first premolar teeth that are erupting into its position along with all 4 deciduous canines. Then once this is done the canines and incisors are properly aligned in their spaces. Narn's method is again very similar. Extraction of deciduous first molars followed by extraction of first premolars, deciduous canines allowing canines to erupt in alignment. Now Moyer's method is slightly different. Here extraction of all deciduous lateral incisors is done first B. Then wait for 7 to 8 months. Then extract all deciduous canines. Extract all deciduous first molars followed by premolars. Then finally this provides space and align canines. The sequence here is B C D4. Now there are certain problems that can be encountered in the case of serial extraction. Inadequate root paralleling, buckle enter digitization of the teeth. Space closure and alignment can be a difficult issue. Then it may worsen cases of overbite and overjet that is excessive. It can lead to excessive overbite and overjet. Skeletal profile disharmonies and anchorage considerations are also important to be kept in mind because this is important for comprehensive orthodontic treatment. So all these factors need to be kept in mind. So serial extraction is like a double H4. It has its own advantages and disadvantages which it requires a very comprehensive diagnosis before its implementation and you need to carry on the case only if you are very sure that the patient is an ideal candidate for serial extraction. So the main points to be remembered under this topic is the definition, the indications for serial extraction, the contraindication, advantages and disadvantages and the three main sequences or procedures of serial extraction that is to eat NANs and devil's method. These are the three methods that are important to remember the sequence in which the extraction is done. So serial extraction does not eliminate the need for comprehensive orthodontic treatment. However, if it can be done efficiently, it can shorten the length of the treatment that is required in the eventual stages of life. Thank you.