Infraocclusion
Classification of infraocclusion
| Slight | Between occlusal surface and interproximal contact, less than 2mm. |
| Moderate | Within occluso-gingival margins of interproximal contact. |
| Severe | Below interproximal contact point. |
Etiology (damage to HERS → break in PDL continuity → contact of cementum & dentin with bone)
-infraocclusion mostly seen in primary 1st molars (up to 9%) , more common btw siblings, mand molars more common, bilateral more common
-associated with absence of permanent successors (very common)
Diagnosis
-Visual and tactile examination : infraoccluded primary teeth lies apical to occlusal plane
-Percussion : metallic, high pitched percussion sound
-Mobility : of infraoccluded teeth (mobile → successors are present, not mobile → absent)
-Radiographs : verify presence / absence of successors
(OPG preferred cause infraocclusion is associated with bilateral presentation, and with other dental anomalies) For ankylosis, can look for loss of PDL space (but s/t only certain points are ankylosed, so not so visible in X ray
- If Es are infraoccluded by 0.5-2mm, mobile → successors are present (no need X ray)
- If Es are infraoccluded >2mm, firm, metallic percussion sound, +ve family history → successors absent (need X ray)
Consequences :
| Tipping of adjacent teeth | Orthodontic uprighting
Food impact ,Risk of caries |
| Supraeruption of opposing tooth → encroach interocclusal space (make it difficult for prosthesis placement in the future & leads to premature occlusal contact, causing shift of occlusion) | Orthodontic intrusion |
| Lateral open bite | Ortho tx |
| Caries of infraoccluded teeth / adj teeth | Restoration |
| Delayed exfoliation of primary teeth
Impaction of successors |
Extraction |
| Increased difficulty of extraction (# of primary tooth roots) | Surgical extraction |
Tx planning :
-presence/absence of permanent successors
- Present : primary tooth will exfoliate within 6 months later than contralateral normal tooth.
-Monitor the child every 3m and take X rays to look for signs of resorption of primary tooth.
-May need to re-establish occlusal table & MD dimension of infraocc primary (comp, onlay, SSC)
-If no root resorption, significant tipping of adj teeth, delayed exfoliation >6m, consider xla
- Absent :
-Retain with onlays if dentition is not crowded, primary tooth doesnt show much root resorption to restore occlusal level, prevent tipping and overeruption
-Xla if crowded arch with ortho tx plan
-age of onset and severity
- If xla is needed when child is young, may require space maintainer and monitoring of eruption of permanent successors
- The younger the age at diagnosis, the more rapid rate of progression, the more potential for alveolar development disruption, then higher chance of requiring intervention
-tipping/supraeruption of neighbouring teeth
-infraocclusion seen in multiple teeth (require referral to orthodontist)