Interceptive Orthodontics PDF

Course Learning Outcomes (CLOs) CLO1-Define the concept of orthodontic patient examination and diagnosis in r...

Course Learning Outcomes (CLOs) CLO1-Define the concept of orthodontic patient examination and diagnosis in relation to the malocclusions (with possible etiologies) and differentiate skeletal vs dental malocclusion in addition, distinguish minor tooth movement cases and major malocclusions Interceptive Orthodontics CLO2-Assess the orthodontic records (study model, Cephalometric X-ray, facial photographs) and make conclusions and transforms this data into organized problem list CLO3- Discuss the different types of tooth movement and the biological Dr. Huda Abutayyem theories of orthodontic tooth movement and describe the principles of PhD, MSc, DDS, LDS RCS (Eng), MOrth RCSEd (Edin), MFDS RCS (Edin), MOrth RCPSGlasgow, MFDS RCPS Glasgow, MFDS RCS England, CPHQ growth modification, and the effects of orthodontic force on the maxilla Assistant Professor and Consultant Orthodontist and on the mandible CLO4- possible treatment options according to analyses results and select the proper option depending on patient’s socio-economic status chief complaint and establish a final treatment plan 1 2 Outline Definition Definition Main aims Normal dental development Interceptive orthodontic treatment Any treatment procedure which, eliminates or reduces the severity of a developing malocclusion as this Abnormalities of eruption & exfoliation may reduce the need for further treatment or make this simpler Mixed dentition problems Planned extraction of deciduous teeth Other dental & skeletal problems 3 4 Outline Main aims: Definition minimise extent of developing malocclusion by: – maintain midline Main aims – minimise crowding – Prevent development of full unit CI ll molars Normal dental development prevention of trauma psychosocial factors Abnormalities of eruption & exfoliation Mixed dentition problems Planned extraction of deciduous teeth Other dental & skeletal problems 5 6 1  Outline Calcification and eruption time Definition It is important to realize that ‘normal’ in this context means average, rather than ideal Main aims It is helpful for assessing dental as opposed to chronological age; for Normal dental development determining whether a developing tooth not present on radiographic examination can be considered absent Abnormalities of eruption & exfoliation Mixed dentition problems Planned extraction of deciduous teeth Other dental & skeletal problems 7 8 Average calcification & eruption time- Average calcification & eruption time- Primary dentition: Permanent dentition: 9 10 Normal dental development Mixed dentition phase starts from age 5-6yrs to exfoliation of the last primary tooth Flush terminal plane typically the 1st molars erupt into 1/2 unit ll upper permanent incisors erupt molar relationship guided by the distal into a wider arc and more surfaces of the 2nd primary molars (flush terminal plane) proclined than the primary incisors (Incisor Liability) transition to Class I molars occurs as a result of: Class I molar – early mesial drift of lower 6 into primate space – late mesial drift of lower 6 into Leeway space – differential mandibular growth upper canines develop palatally, but migrate buccally to lie distal to Leeway space: the root apex of the lateral incisors in maxilla = 1.5mm on each side in mandible = 2-2.5mm on each side 11 12 2  Outline Routine “screening” Definition by GDPs from 8-10yrs old, monitoring developing dentition and looking for abnormalities Main aims clinical exam —“recognise the unusual’ If an abnormality is suspected, then further investigation including radiographs is Normal dental development indicated. R/Gs only if clinically justified, commonly panoramic x-ray Abnormalities of eruption & exfoliation always apply A.L.A.R.P. principle (as low as reasonably practicable) to Mixed dentition problems radiography Planned extraction of deciduous teeth Other dental & skeletal problems 13 14 Natal teeth Natal tooth: is a tooth, which is present at birth, or erupts soon after around 9–10 years of age: it is important to palpate the buccal sulcus for the permanent maxillary canines in order to detect any abnormalities in the eruption path of this tooth. Neonatal teeth: are teeth that erupt within the first few weeks after birth. by the age of 10: the permanent maxillary canines will be palpable buccally These most commonly arise anteriorly in the in 70% of cases mandible- lower primary incisor which has erupted prematurely by the age of 11: these teeth are palpable buccally in 95% of patients. Because root formation is not complete at this stage, natal teeth can be quite mobile, but they usually become firmer relatively quickly Management: – If the tooth is symptomless, it can be left in situ. – If the tooth (or teeth) interferes with breastfeeding or is so mobile that there is a danger of inhalation, removal is indicated 15 16 Eruption cyst Failure/ delayed eruption Causes: There is a wide individual variation in eruption times – an accumulation of fluid or blood in the follicular space overlying the crown of an a period of observation is indicated. However, the following may be erupting tooth indicators of some abnormality and therefore warrant further investigation Ø A disruption in the normal sequence of eruption. Management: Ø An asymmetry in eruption pattern between contralateral teeth. If a – They usually rupture spontaneously tooth on one side of the arch has erupted and 6 months later there – very occasionally marsupialization may is still no sign of its equivalent on the other side, radiographic be necessary examination is indicated. 17 18 3  Causes of delayed eruption: Local causes: Generalized causes: In the majority of children, local factors will be the main cause of any eruption A number of systemic conditions are associated with delayed eruption and disturbances that do occur and is usually due to mechanical obstruction. this these can affect both dentitions. is advantageous as if the obstruction is removed then the affected tooth/teeth has/have the potential to erupt Local causes: Generalized causes: Congenital absence Down syndrome Crowding Cleidocranial dysplasia Trauma Turner syndrome Hereditary gingival fibromatosis Ectopic position of the tooth germ Supernumerary teeth Cleft lip and palate Retained primary teeth Rickets Early extraction of primary teeth Primary failure of eruption Dilaceration 19 20 Unerupted permanent maxillary incisors The maxillary central incisor is the third most Management: commonly impacted tooth after third permanent molars and maxillary canine Primary management depend on ensuring adequate space exists in the Diagnosis: dental arch to accommodate the unerupted tooth and removing any A discrepancy in eruption between contralateral potential obstruction. maxillary incisors of greater than 6 months, or In these circumstances, the majority of teeth will erupt. eruption of lateral incisors before the centrals If this fails to happen, or the unerupted tooth is ectopic from its normal warrants radiographic investigation path of eruption, surgical exposure, with or without orthodontic traction, may be required to accommodate the affected tooth into the dental arch Etiology: The most common cause of impeded eruption of a maxillary incisor is barrel-shaped tuberculate supernumerary tooth. Early removal may facilitate spontaneous eruption Trauma to the primary dentition, which may lead to dilaceration of the permanent successor/s could be another etiological factor 21 22 Management options: Removal of a physical obstructions: Surgical intervention: RCSEng Guidelines on unerupted maxillary incisors Surgical removal of obstruction, surgical exposure of maxillary incisor teeth with orthodontic traction Open exposure: Recommendations: Ø Simple elliptical incision: soft tissue impaction Closed eruption technique: In the younger patient (9 years of age) its resonable to consider “open” or with a mature permanent maxillary “closed” surgical exposure with bonding Incisor removal: incisor an orthodontic attachment at the time of removal of any obstruction, especially if Autotransplantation: the unerupted inciosr is high 23 24 4  Unerupted permanent maxillary canines (Impacted Maxillary canine) Deviation from the normal path of eruption can occur in either a palatal or buccal direction, but in the majority of Diagnosis: cases (up to 85%) it will be palatal and the tooth will become impacted. – Family history Although the canine can also impact on the buccal side – Intra-oral examination: or within the line of the arch, these cases are often canine should be palpable manifestations of crowding rather than true ectopia between 8-10 years Aetiology: (Multifactorial) If not palpable then further investigation – a long path of eruption – Radiological examination: – Reliance upon the maxillary lateral incisor root for guidance of eruption, which can be lacking if these teeth are diminutive or congenitally absent – Retention of the primary canine – Chronology of eruption, in the maxillary arch the canine often erupts after the first premolars – A genetic susceptibility (a familial tendency, in association with ectopic maxillary canines and a female predilection) 25 26 Treatment options: Outline – the treatment of choice is generally surgical exposure followed by orthodontic alignment Definition – Autotransplantation – extract the impacted canine Main aims – leave it in situ Normal dental development Abnormalities of eruption & exfoliation Mixed dentition problems Planned extraction of deciduous teeth Other dental & skeletal problems 27 28 Enforced and elective extractions: Balancing and compensating extractions: A balancing extraction is the removal of a tooth from the opposite side of the same dental arch to preserve the centreline by maintaining Enforced extraction: is when you have to extract the tooth as it arch symmetry has a poor prognosis A compensating extraction is the removal of a tooth from the opposing quadrant to maintain the buccal occlusion by allowing molar Elective extraction: we decide to extract or not depending on the teeth to drift forwards in unison. treatment plan (the tooth doesn’t have to be extracted, but we are extracting it for some reason or the other Balancing and compensating extraction of primary teeth aims to preserve arch symmetry and occlusal relationships by extracting contralateral and opposing teeth, respectively to those requiring enforced extraction 29 30 5  Current guidelines for balancing (balance-enforced) and compensating (compensate-enforced) extractions of primary teeth are available from the Royal The decision to carry out a balancing or compensating extraction will College of Surgeons of England (Rock, 2002). depend upon a number of factors. However, before the elective extraction of any primary tooth is instituted, a radiographic screen It is acknowledged that although supported by the best available data where possible, the lack of research in this area means that these guidelines are based should be carried out to check for the presence, position and normal primarily upon clinical opinion. formation of the developing permanent dentition. – It is not necessary to balance or compensate the loss of a primary incisor from either dental arch Any other primary teeth of questionable prognosis should also be – The premature and unilateral loss of a primary canine is often associated with a considered as candidates for balancing or compensating extraction, centreline shift and a balancing extraction can help to preserve the centreline; however, compensating extractions are not required in this situation particularly if general anaesthesia is required. It can be more difficult – The premature and unilateral loss of a first primary molar can also induce a to justify these extractions if local anaesthesia is used for the centreline shift, particularly in a crowded arch and a balancing extraction may be required to preserve the centreline elective extraction of a single symptomatic tooth and cooperation for – Second primary molars do not require balancing extractions; however, early further extractions may be poor. extraction may allow significant forwards movement and tilting of the adjacent first permanent molar. Therefore, consideration should be given to fitting a space maintainer – In general, compensating extractions for primary first and second molars are not necessary (unless some of these teeth are restored and the child is having a general anaesthetic). 31 32 Possible problems in the developing Early loss of Primary teeth dentition Early loss of Primary teeth The early loss of primary teeth is usually the result of extraction due Prolonged retention of primary teeth to caries or trauma and can have implications for the developing Ankylosis and infraocclusion occlusion; in particular, future space distribution and symmetry within the affected dental arch. Hypodontia Supernumerary teeth The timing of primary tooth extraction can also influence the eruption Early loss of permanent teeth rate of permanent successors. Oral Habits Very early loss of primary teeth can delay successional tooth eruption whilst later extraction can have the opposite effect 33 34 Early loss of Primary incisors: Early loss of Primary canines: Primary canines are not often lost premature loss of a deciduous incisor has little impact, mainly because they are shed prematurely; but when they are, this relatively early in the mixed dentition can lead to a centreline shift towards unless they are lost very early as a result the affected side in unilateral cases, of particularly in a crowded dentition – trauma or – early resorption secondary to crowding Truama possible consequences: – Turner tooth Consequences: – Dilaceration with or without failure of Unilateral loss g midline shift eruption – Thickening of gingiva with delayed Loss of space of the permanent canine with potential crowding eruption and impaction or ectopic eruption Prevention g balancing extraction ( contralateral tooth) 35 36 6  Early loss of Primary first molars: Early loss of Primary second molars: unilateral loss of this tooth may result in a Primary second molars less commonly centreline shift, particularly in cases of affect the centreline when lost prematurely crowding. In most cases, balancing or compensating in most cases, an automatic balancing extractions of other sound second primary extraction is not necessary, but the centreline molars is not necessary unless they are should be kept under observation and, if also of poor long-term prognosis indicated, a tooth on the opposite side of the arch removed. Early loss of Es do influence the position of the first permanent molar. in the presence of crowding, early loss of Early loss of E can result in: these teeth can also result in space loss – if unerupted: forwards bodily movement of the first through forwards movement of the buccal molar tooth segments and accentuate premolar crowding – if it is erupted: tipping and rotation of the first molar This can result in space loss and premolar crowding, the severity reflecting the amount of forwards movement that has occurred. 37 38 Impacted first permanent molars Impaction of a first permanent molar tooth against the second deciduous molar is It should be emphasized that the suggestions regarding premature indicative of crowding. loss of deciduous teeth , not rules, and at all times a degree of common sense and forward planning should be applied—in essence It most commonly occurs in the upper a risk–benefit analysis needs to be worked through for each arch child/tooth. Spontaneous disimpaction may occur, but The effect of early extraction of a primary tooth on the eruption of its this is rare after 8 years of age successor is variable and will not necessarily result in a hastening of eruption. 39 40 Management: Prolonged retention of primary teeth Observe for 6 months for self correction, if not considered the following options: A difference of more than 6 months between the shedding of contralateral teeth should be regarded – If Mild cases: (ovelap between the E & 6 is less than with suspicion and should be investigated 2mm) radiographically - can be managed by tightening a brass separating wire around the contact point between the two teeth over a period of about 2 months. Provided that the permanent successor is present, retained primary teeth should be extracted, – Severe cases of impaction: (ovelap between the E & 6 particularly if they are causing deflection of the is more than 2mm) permanent tooth – an appliance can be used to distalize the permanent molar and disimpact it. – Or it can be kept under observation It is common to find a permanent successor failing to – Or extraction of the deciduous tooth may be adequately resorb the roots of an overlying primary indicated if it becomes abscessed or the tooth during its eruption. The patient should be permanent tooth becomes carious and encouraged to exfoliate these retained primary teeth restoration is precluded by poor access. The themselves and if this is not possible, they should be resultant space loss can be dealt with in the extracted under local anaesthetic particularly if they permanent dentition. are causing deflection of the permanent tooth 41 42 7  If the permanent successor is present: management is dictated primarily by the Crowding, an ectopic position, impaction or amount of space available within the dental agenesis of the permanent successor can arch and the position of the unerupted also lead to prolonged retention of the permanent tooth. overlying primary tooth – If space is available, extraction of the primary tooth alone can often lead to successful Commonly encountered scenarios include: eruption if the permanent tooth is in a – retention of a primary central incisor or favourable position canine due to impaction of the permanent successor – If space is at a premium, maintenance may be – retention of a primary second molar due to required following removal of the primary agenesis of the second premolar. tooth, or alternatively space will need to be created 43 44 If the permanent successor is absent: If the position is less favourable: the long-term prognosis for most of these – exposure of the permanent tooth (with or primary teeth will be poor and they will without the application of orthodontic either be lost naturally or ultimately traction) may also be required require extraction. they can often act as useful maintainers of arch space or alveolar bone in the shorter term and can often be left in situ until – Extraction of the permanent tooth may definitive treatment. be considered if the position is poor, either in isolation or in combination with other teeth as part of an orthodontic treatment plan. The decision to extract will also be influenced by the type of tooth under consideration. 45 46 infra-occluded (submerged) primary A consequence of ankylosis can be: teeth the process where a tooth fails to achieve or – the apparent ‘submergence’ or maintain its occlusal relationship with adjacent or infraocclusion of the tooth relative to the opposing teeth. occlusal plane. This occurs in the growing child because alveolar bone and occlusal height increase with Most infraoccluded deciduous teeth erupt into development, whilst the position of the occlusion but subsequently become ‘submerged’ ankylosed tooth remains fixed. because bony growth and development of the adjacent teeth continues A number of factors are thought to contribute: – Genetic predisposition – Failure of normal resorption by the permanent successor – Agenesis of the permanent successor – Trauma – Infection 47 48 8  In the presence of a permanent successor and minimal infraocclusion: – the ankylosed tooth can usually be left under observation to exfoliate naturally If the infraocclusion becomes greater: – this can lead to displacement and tipping of Management of infra-occluded primary second molars adjacent teeth, and overeruption of opposing teeth. – In these circumstances, consideration should be given to either restoring the vertical dimension or extracting the affected tooth. Direct resin composite restorations can be effective for the transitional. restoration of infraoccluded second primary molars In the absence of a permanent successor: – a decision will need to be made regarding long-term management of the missing tooth within the occlusion. – the presence of ankylosis or infraocclusion in a growing patient will often make extraction more likely. 49 50 Ankylosed permanent maxillary incisors Hypodontia In the permanent dentition, ankylosis is most commonly seen in association with Hypodontia: is a developmental absence of one tooth or more excluding maxillary central incisors as a result of 8’s. trauma. Hypodontia is also used as a generic term to describe developmental tooth absence, but the definition is actually more specific In particular, intrusion and avulsion injuries – Hypodontia: refers to an absence of one to six teeth, excluding third molars can lead to replacement resorption, – Oligodontia: refers to an absence of more than six teeth, excluding third molars ankylosis and infraocclusion – Anodontia: refers to a complete absence of teeth in one or both dentitions Management: Possible consequences: – depend upon a number of factors, but Centerline shift the worst affected will ultimately require Spacing extraction and either space closure or Malposition restorative replacement Retained deciduous teeth with risk of submerging and ankylosis Overeruption of opposing teeth in the maxillary arch 51 52 Management: Supernumerary teeth In simple terms, the management of tooth A supernumerary tooth: is one that is additional to the normal series, agenesis will involve either: and can occur within either dentition. Space closure The aetiology is not completely understood, but appears to have a genetic Maintenance or opening of space, followed component. It occurs more commonly in males than females. by prosthetic replacement of the missing tooth units. Supernumerary teeth occur individually or in groups and can be unilateral or bilateral. These teeth are found most frequently in the anterior maxilla, but are also seen in the premolar and molar regions. 53 54 9  Effects of supernumerary teeth and their management: In the permanent dentition, the majority of supernumerary fail to erupt and are asymptomatic, only being discovered Supernumerary is classified based on morphology and position: during routine radiographic screening. However, they can also cause dental problems, which include: – Postition: 1. Mesiodense – Failure of tooth eruption: the presence of a 2. Paramolar supernumerary can prevent the eruption of a permanent tooth. In these circumstances, the supernumerary 3. Distomolar should be removed – Morphology 1. Conical – Displacement: a supernumerary tooth can be 2. Tuberculate associated with displacement or rotation of an erupted 3. Supplemental permanent tooth. Management involves firstly removal 4. Odontome of the supernumerary, usually followed by fixed appliances to align the affected tooth or teeth. – Crowding: supernumerary teeth can contribute to dental crowding, These supernumerary teeth will usually require extraction as part of a definitive orthodontic treatment plan. 55 56 – Spacing: supernumeraries can also produce spacing Primary failure of eruption (PFE) between erupted teeth, particularly a mesiodens producing a maxillary diastema between the central incisors. If orthodontic space closure is planned, these supernumeraries will require extraction In some circumstances an eruption failure can occur, which has no identifiable local or systemic cause. – Cystic formation: as with any unerupted tooth, cystic formation can occur. Any evidence of follicular a rare, isolated condition associated with localized failure of tooth enlargement or cystic formation and these teeth should eruption, which most commonly affects the molar dentition. be removed. – No effect: not affecting the occlusal relationships of the Cause: erupted dentition can be left in situ. These teeth should – it has recently been suggested that the autosomal dominant mutations in be kept under periodic radiographic review to ensure PTH1R that cause PFE may also be associated with osteoarthritis they are not damaging any adjacent structures or undergoing cystic change. 57 58 Transposition Management: Dental transposition: is the complete positional interchange of two adjacent teeth, or the development or eruption of a tooth in a position normally occupied by a non-adjacent tooth Management of PFE is difficult because active orthodontic extrusion will normally result in ankylosis and a failure to bring an affected tooth into occlusion. Causes: – The positional interchange of developing tooth Extraction, followed by either orthodontic space closure or prosthetic buds replacement, is usually indicated. – Alteration of tooth eruption paths – Retention of primary teeth Alternatively, localized bony osteotomy and orthodontic extrusion of the whole segment can be attempted. If some eruption of the tooth has – Trauma occurred, a localized coronal build up may be the treatment of choice to improve the vertical position. Cases where multiple teeth are involved are more difficult to manage, the only available method of bringing them into occlusion being a segmental osteotomy 59 60 10  Dilaceration Dilaceration is a distortion or bend in the root of a tooth. Management options: Definitive treatment of an established transposition will involve either: It usually affects the upper central and/or – Correcting the order of affected teeth lateral incisor. – Accepting the transposed order – Extracting one of the affected teeth Presented as delayed eruption. Can cause failure of eruption, midline shifts, difference in alveolar bone height Diagnosis reached by taking history and radiographs. 61 62 Aetiology: Median diastema – Developmental: this anomaly usually affects the crown of the affected tooth is turned upward and labially and no disturbance of enamel and dentine is Aetiology: seen – Trauma: intrusion of a deciduous incisor leads to displacement of the underlying developing – Physiological (normal dental development) permanent tooth germ. Characteristically, this – Familial or racial trait causes the developing permanent tooth crown to be – Small teeth in large jaws (a spaced deflected palatally, and the enamel and dentine dentition) forming at the time of the injury are disturbed, giving rise to hypoplasia. – Missing teeth – Midline supernumerary tooth/teeth – Proclination of the upper labial segment Management: – Prominent fraenum. – Dilaceration usually results in failure of eruption. If mild: may be able to expose and apply traction If severe: may require extraction and space maintenance 63 64 the upper midline fraenum can contribute to the persistence of a a midline diastema is a normal feature of the diastema: developing dentition: Factors, which may indicate that this is the case, – Ugly Duckling Stage: around the age of 8-9 include the following: years. A median diastema is normally present between the maxillary permanent central When the fraenum is placed under incisors when they first erupt. As the lateral tension there is blanching test of the incisors and then the canines emerge, the incisive papilla. diastema usually closes. Radiographically, a notch can be seen at the crest of the interdental bone between the upper central incisors 65 66 11  Management: Oral Habits It is advisable to take a periapical radiograph to exclude the presence of a midline supernumerary tooth prior to planning treatment for a midline diastema. Oral habits __ such as thumb/digit sucking, mouth breathing, tongue In the developing dentition: thrusting, lip sucking, etc. tend to cause malocclusions – if a diastema of less than 3 mm rarely warrants intervention – if the diastema is greater than 3 mm and the lateral The more the frequency and intensity of the habit → the more incisors are present, it may be necessary to consider appliance treatment to approximate the central incisors severe the developing malocclusion to provide space for the laterals and canines to erupt. – Care should be taken to ensure that the roots of the teeth being moved are not pressed against any If thumb sucking persists after the primary teeth have erupted, then unerupted crowns as this can lead to root resorption. If the crowns of the teeth are tilted distally, an upper it can change the growth patterns of the jaw, and cause significant removable appliance can be used to approximate the teeth, but usually fixed appliances are required. malalignment of the teeth Closure of a diastema has a notable tendency to relapse, therefore long-term retention is required. This is most readily accomplished by placement of a bonded retainer. 67 68 A prolonged digit-sucking habit can affect the eruptive position of the teeth, often giving rise to a number of characteristic features as part of a malocclusion, which frequently manifest in the late primary or How to stop the habit ? early mixed dentitions: – Anterior open bite (often with a degree of asymmetry) – Proclination of the upper incisors – Narrow maxillary arch – Posterior crossbite Younger than 6 years 7 years & older – Increased lower face height Nail paint, Intra-oral Rewarding gloves on fingers appliances 69 70 Management: 1. Non-physical methods should be attempted first, with patient and parent education. 2. Non-invasive methods include: These techniques should be attempted for 3−6 – If the intervention to break the habit started early: then most of the months. features of malocclusion associated with the thumb sucking habit will be - Psychological treatment: spontaneously corrected except for the narrow maxilla and potential 1. positive reinforcement cross bite (it will not get worse, but it will not be spontaneously 2. habit reversal: the child is taught to carry corrected). Another phase of treatment may be needed. out an alternative activity when the urge to suck arises – If these problems are not diagnosed until the patient is in the permanent - Other possibilities include the use of plasters, dentition: it can be complex, time-consuming and costly to correct the gloves or bitter flavoured agents applied to the digit to make the habit less satisfying problem and, in severe cases, it can even require orthognathic surgery to correct the anterior open bite. 3. Where the habit persists, simple fixed habit- breaker appliance These appliances used for 6 to 12 months. -including palatal arches with one of a variety of projections. 71 72 12  First permanent molars of poor long-term Early loss of permanent teeth prognosis Definition of poor prognosis of first molar: which needs a 2-surface The most common reasons for the early loss of permanent teeth are restoration, hypoplastic teeth, MIH (molar incisor hypomineralisation), or trauma and caries. extensive caries The integrity of the first permanent molars is The permanent maxillary incisor dentition is most vulnerable to often compromised due to caries and/or hypoplasia secondary to a childhood illness. trauma, particularly in males with an increased overjet, whereas the first permanent molars are most commonly affected by caries. Treatment planning for a child with poor-quality first permanent molars is always difficult because several competing factors have to be Treatment planning for either of these conditions can be challenging considered before a decision can be reached for a particular individual. First permanent molars are rarely the first tooth of choice for extraction as their position within the arch means that little space is provided anteriorly for relief of crowding or correction of the incisor relationship unless appliances are used. 73 74 Factors to consider when assessing first permanent molars of poor Ultimate (optimal) time pf first permanent long-term prognosis: molar extraction It is impossible to produce hard and fast rules regarding the extraction of first permanent molars, and therefore the following should only be considered a starting point: What is optimal time for Extraction? – Check for the presence of all permanent teeth. If any are absent, extraction of the first permanent molar in that quadrant should be avoided. 1. The average chrolongical age 8-10 years – If the dentition is uncrowded, extraction of first permanent molars should be avoided as space closure will be difficult. 2. Bifurcation area of 7 developing 3. 15-30 degree angulation of 7 with 6 – In the upper arch: remember that in the maxilla there is a greater tendency for mesial drift and so the timing of the extraction of upper first permanent molars is less critical if 4. Overlpas of the 7 follicle with the 6 distal root aiming for space closure. 5. Follicle of the 8 is present → you don’t want to extract the 6 and be left with one molar only. – In the lower arch, a good spontaneous result is more likely if: (a) the lower second permanent molar has developed as far as its bifurcation (b) the angle between the long axis of the crypt of the lower second permanent molar and the first permanent molar is between 15° and 30° (c) the crypt of the second molar overlaps the root of the first molar (a space between the two reduces the likelihood of good space closure). 75 76 Extraction of the first molars alone will relieve buccal Consequences of early extraction of 6s segment crowding, but will have little effect on a crowded labial segment. If space is needed anteriorly for the relief of labial segment crowding or for retraction of incisors (i.e. the Second premolar can drift distally into the extraction space, tip and upper arch in Class II cases or the lower arch in Class III rotate cases), then it may be prudent to delay extraction of the first molar, if possible, until the second permanent molar has erupted in that arch. The space can then be utilized, in conjunction with appliance therapy, for correction of The labial segements can retrocline with increase overbite the labial segment. Serious consideration should be given to extracting the opposing upper first permanent molar, should extraction of a lower molar be necessary. If the upper molar is not extracted, it will over-erupt and prevent forward drift of the lower second molar A compensating extraction in the lower arch (when extraction of an upper first permanent molar is necessary) should be avoided where possible as a good spontaneous result in the mandibular arch is less likely. Impaction of the third permanent molars is less likely, but not impossible, following extraction of the first molar. 77 78 13  Consequences of late extraction of lower 6 Consequences of late extraction of upper 6 Adverse effects are less critical in maxillary arch Mesial tilting and lingual rolling of 7’s Lower 6 rarely overerupt Overeruption of the opposing 6 Distal drifting and tilting 0f 5’s Incomplete space closure Significant loss of alveolar bone can occur in these regions of spacing, which can make subsequent orthodontic space closure difficult. 79 80 Outline Serial extraction Definition Serial extraction as an interceptive orthodontic procedure was originally Main aims popularized by Bjerger Kjellgren Normal dental development This technique aims to produce a well- aligned dentition in cases with a full Abnormalities of eruption & exfoliation complement of teeth and no significant sagittal discrepancy, without the need for orthodontic appliances. Mixed dentition problems Planned extraction of deciduous teeth Other dental & skeletal problems 81 82 Essentially, serial extraction involves: As a complete sequence it is no longer recommended for a number of – Extraction of all the primary canines as the permanent lateral incisors are reasons: erupting, which provides space for these teeth to align – Extraction of first primary molars around 12 months later to encourage – The child undergoes progressive extraction of twelve teeth eruption of first premolars in advance of the permanent canines – In the maxilla, premolars usually erupt before the permanent canines anyway – and Ultimately, extraction of the first premolars as the permanent canines are – Extraction of first primary molars can result in significant buccal beginning their eruption, as this allows for their spontaneous alignment segment space loss if the permanent canine does erupt before the first premolar – An aberrant position of the maxillary canine can mean a failure to erupt even after premolar extraction – A fixed orthodontic appliance may be needed anyway to produce good final alignment and close any residual space. It is easier, simpler and more predictable to wait until the early permanent dentition before undertaking premolar extraction and orthodontic alignment. 83 84 14  Extraction of deciduous canine Outline There are a number of occasions where the timely extraction of the deciduous canines may avoid more complicated treatment later: Definition – In a crowded upper arch: the erupting lateral incisors may be forced palatally. In a Class I malocclusion, this will result in a crossbite and in Main aims addition the apex of the affected lateral incisor will be palatally positioned, making later correction more difficult. Extraction of the deciduous canines while the lateral incisors are erupting often results in them being able to escape spontaneously labially into a better position. Normal dental development – In a crowded lower labial segment: one incisor may be pushed through the labial plate of bone, resulting in a compromised labial periodontal Abnormalities of eruption & exfoliation attachment. Relief of crowding by extraction of the lower deciduous canines usually results in the lower incisor moving back into the arch and improving periodontal support Mixed dentition problems – Extraction of the lower deciduous canines in a Class III malocclusion can be advantageous. Planned extraction of deciduous teeth – To improve the position of a displaced permanent canine Other dental & skeletal problems 85 86 Crossbites in the mixed dentition Anterior crossbite Teeth can erupt into a position of crossbite An anterior crossbite can cause gingival during the mixed dentition, either individually recession associated with the lower incisors or within a group. if there is a displacement on closing, particularly if these teeth are displaced labially. This is an indication for treatment in Early correction is indicated, particularly if the mixed dentition and correction can be the crossbite is associated with a achieved with removable or fixed URA mandibular displacement or periodontal appliances. damage, and this can be achieved relatively easily during the mixed dentition. In the presence of a positive overbite, a corrected anterior crossbite will usually be self-retaining 2X4 fixed appliance system Management: Removable appliances Fixed appliances 87 88 Posterior crossbite Management: A posterior crossbite in the mixed dentition can Grinding of premature occlusal contacts in the primary dentition be an early manifestation of a skeletal discrepancy, or be related to a persistent digit- sucking habit and can occur unilaterally or - Removable appliances: bilaterally. Correction can occasionally be achieved by occlusal grinding in the primary dentition; however, more commonly a removable There is a weak association between posterior appliance with a midline expansion screw crossbite with displacement and the later can be used in the early mixed dentition development of temporomandibular dysfunction - Fixed appliances: Fixed palatal expanders such as a quadhelix it is considered appropriate to correct a or trihelix can be used for expansion in the posterior crossbite and eliminate the mixed dentition, especially if some skeletal change is also desired. displacement as early as possible and a number of relatively simple methods are available to do this 89 90 15  Skeletal problems in the mixed dentition Class II/1 malocclusion with increased OJ Skeletal discrepancies can also manifest during the mixed dentition and will Class II malocclusions are amenable to early often respond well to early intervention. treatment using headgear or functional appliances; however, the timing of treatment However, the potential advantages associated with early correction need to should be carefully considered. be considered in relation to disadvantages over the longer term, namely maintaining any correction during subsequent facial growth and the fact that a shorter course of treatment in the late mixed or early permanent dentition Increased overjet and inadequate lip coverage will almost certainly achieve the same result. increases the risk and severity of incisor trauma The only advantage of an early treatment is an to decrease the risk of trauma, increase in self- confidence and a reduction of negative social experiences Otherwise treatment is best started in the early adolescence (during growth spurt). 91 92 Class III malocclusion A reduced or reverse overjet in the mixed dentition is A class III malocclusion on a skeletal I base with a significant forwards usually a sign of an underlying class III skeletal mandibular displacement is sometimes referred to as a ‘pseudo class III relationship and this will often worsen with age. malocclusion’, because the incisor relationship does not reflect the underlying skeletal relationship Treatment decisions are often delayed at this stage to monitor further growth and to better determine the This type of class III malocclusion is very amenable to early orthodontic extent of the skeletal problem; however, early treatment, but creating a positive overbite as well as overjet is crucial for treatment may be considered in patients with the stability following correction. following features: – Skeletal class I, or only mildly class III – Maxillary retrusion – An average or reduced lower face height – A large anterior displacement on closing 93 94 Recommendations for practice As a general rule: Class II treatment can be deferred until near adolescence (growth spurt) because treatment then is equally as effective as earlier treatment Class III treatment for maxillary deficiencies should be addressed earlier and Class III treatment for protrusive mandibles requires either Class III camouflage orthodontic treatment (the less severe cases) or orthognathic surgery after growth has essentially stopped 95 96 16  Reference: Author Title Edition/Year Publisher 5th Simon J. Littlewood & Introduction to Orthodontics / 2019 Oxford Laura Mitchell RCS Guidelines - Royal College of Surgeons- Faculty of Dental surgery: -A guideline for the extraction of First Permanent Molars in children -2014 -A guideline for the Management of unerupted Maxillary incisors- 2016 97 98 17