Occlusal problems in the mixed dentition

Abnormalities and tooth formation

crowns rood dilaceration - 50% are impacted

  • Abrupt change in the axial inclination between the crown and root of a tooth

  • 2 causes:

    • Trauma

    • Idiopathic

  • Management:

    • Depends on severity and other aspects of the malocclusion

    • If unerupted often have closed exposure and orthodontic alignment or surgical removal

    • If erupted align whilst mainining the root within alveolar bone or xla

tooth sidle/shape discrepancies

  • Unknown aetiology

  • Affects incisors - peg laterals

  • Often due to hypodontia

  • Increased risk of ectopic maxillary canine

Supernumerary

  • Extra teeth:

    • Supplemental - duplicate of the same tooth

    • Odontonome

    • Conical - peg shaped

    • Tuberculate - barrel shaped

  • Mesiodens - when they occur in the maxillary midline

  • Can impede eruption of adjacent teeth

  • Management options - leave and KUO, XLA/ surgical removal

Hypodontia

  • developmental absence of 1 or more teeth

  • Genetic

  • Commonly affects 3rd molars, upper lateral incisor, lower 2nd molars, lower lateral incisors

  • More common in permenant dentition - be sus with delayed exfoliation of primary teeth or late eruption or permenant teeth

  • Poor aesthetics: missing upper central incisors

  • Occlusal impact: infraoccluded Es and missing 5s

Abnormalities in eruption and exfoliation

Neonatal

  • any tooth present at birth

  • Can cause feeing problems

  • XLA if mobile

Eruption cyst

  • appears as blue mucosa overlying an unerupted tooth

  • Most common over E’s and 6’s

  • Usually asymptomatic

Impacted teeth

  • impede eruption do to lack of space

  • Ectopic tooth - forming in the wrong position or due to presence of an obstruction

  • Can be unerupted or partially erupted

Infra occluded deciduous teeth

  • often referred to as submerging (incorrect)

  • Usually due to ankylosis of the deciduous tooth. The Adhactent tooth continues to erupt and the ankylosis tooth remains unchanged, giving the appearance it is submerging

  • Can be due to missing successor tooth or idiopathic

Retained deciduous teeth

  • often appear normal in position

  • Missing permenant successor or ankylosis

  • If ankylosis (tooth fused to the alveolar bone due to loss of PDL) - XLA as can displace the permenant successor

  • Usually leave in situ if no successor until comprehensive Ortho tx in permenant dentition

Premature loss of teeth

caries:

  • GA for multiple XLA

  • Early loss has significant impact on positioning of permanent teeth

  • Often see Mesial drifting of FPMs resulting in premolar crowding

Trauma

  • avulsion of deciduous incisors can result in centreline shift

  • Can result in delayed eruption of permenant successor: fibrous mucosa

  • Intrusion of deciduous incisors can cause dilaceration of permanent successor

Balancing

  • if you XLA on one side of arch you may consider XLA of contralateral tooth to preserve the dental midline

  • Consider when xla C’c + D’s but rarely E’s

compensating XLA

  • if XLA a tooth on one arch consider xla the same tooth on the opposing arch (common when XLA C’s + D’s)

  • Mostly considered for FPM’s

  • If XLA a lower FPM - theoretically risk of overeruption upper FPM

Serial XLA

  • planned sequence of XLA with aim of reliving incisor crowding in the mixed dentition

  • Popular before fixed appliance

  • Involved XLA of Cs to allow improved alignment of permenant incisors, then Ds to encourage 4s to erupt, then 4s upon eruption and await eruption of permenant canines

Early loss of FPM

  • not ideal for Ortho reasons - will not resolve incisor crowding

  • Often due to caries/ MIH

  • Ideally should have all permenant teeth present (check with DPT)

  • Optimum age 9-10 years to encourage Mesial drift of 7s and spontaneous space closure

  • Delay xla if appropriate if space needed for Ortho

Crossbite

  • buccal and lingual cross bite

  • Can affect any tooth or teeth

  • Common incisors or molars

  • Can result in mandibular displacement, tooth wear, gingival recession

  • Can correct in the mixed dentition if causing any problems

Management

  • removable appliance - mixed dentition

    • Slow movement of the teeth

    • Little expansion

  • RME - rapid maxillary expansion

    • Turn the screw 2x a day for up to 2 weeks

    • Ideal for large bone adjustment

  • 2x4 fixed appliance

Habits

Non intrusive sucking habits

  • digit sucking or pacifier

  • Severity of occlusal impact is dependant on duration and intensity of the habit

  • Typically results in:

    • Proclined maxillary incisors

    • Retro lined mandibular incisors

    • Anterior open bite

    • Posterior buccal crossbites

Management

  • positive reinforcement

  • Non-invasive methods such as glove, nail varnish, plasters

  • If unsuccessful try fixed or removable habit breaker appliance

    • Fixed and removable options

Midline Diastema

  • Developement stage

  • Normal dental development

  • Small teeth/large jaws

  • Missing teeth

  • Midline supernumerary

  • Prominent fulcrum

  • Proclined upper incisors

Management

  • Reassure: likely to resolve upon eruption of successor

  • large diastema requires tx with fixed appliance and permenant retention as high relapse potential - retainers (fixed/removable)

Impacted teeth

  • can affect any tooth

    • Es

    • FPMs - usually due to crowding management of Es includes monitoring, place separator or XLA of the E

    • 2nd premolars - following early loss of deciduous molars (common)

    • Impacted centrals

    • Canines

    • Distal of Ds

  • Risk to dental health due to plaque accumulation, caries + gingivitis

  • Consider- monitoring, separator or in some cases XLA

Impacted central insisors

  • supernumerary

  • Crown/root dilaceration

  • Trauma

  • Premature loss of deciduous tooth

  • Clinical and radiographic examination

  • Be suspicious if eruption sequence distrusted or >6 months since contralateral tooth erupted

Management

  • remove obstruction

  • Create space for central incisors

  • Dependant on age either await eruption or surgical exposure with gold chain and orthodontic traction

Impacted canines

  • palpate at 8-10 years old

  • Radiograph

  • Early intervention extract Cs and review

  • If fails to erupt (remains ectopic)

    • Leave in situ and monitor

    • Surgical exposure + Ortho alignment

    • Surgical removal