Transcript PASSIVE SPACE CONTROL
PASSIVE SPACE CONTROL
Dr S.E. Jabbarifar;Isfahan Dental School,Pediatric Dentistry Departement 2009
Prerequisite knowledge
Understand that arch length is greatest at age four years Tooth position is maintained by balance of forces – shift vs. drift Greatest amount of space closure – within first 6 months of premature tooth loss Sequence & timing of exfoliation/eruption
Space control vs. space maintenance
Space control Dynamic Careful ongoing supervision Space maintenance Utilization of appliance to preserve existing space Not always the rule!
Variables influencing space control
Oral musculature & habits Time elapsed since extraction Dental age, eruption sequence & bony covering Available space Interdigitation Absence of anomalies
Considerations in premature 1 o tooth loss
Preserve the arch length!
Causes: Anterior – primarily trauma, caries Posterior – primarily caries If space lost: Space maintenance Space regaining No treatment
Space loss in primary and mixed dentitions
Unrestored interproximal caries reduce arch circumference!
“first line of defense” = Class II & SSC restorations Natural tooth is the best space maintainer
Planning for space maintenance
No medical contraindications Patient must be dentally fit Patient must be able to demonstrate good OH
Planning for space maintenance
Parents must all understand costs involved Parents must understand importance of & be willing to attend regularly for appliance supervision/maintenance – teeth lost in primary dentition stage may cause delayed eruption of succedaneous teeth Periodic recementation may be required
Primary Incisors
Primary Incisors
Primary Incisors
Why replace primary incisors?
Primarily for esthetic reasons Rarely see long-term effects on speech development and function Once 1 o cuspids have erupted in occlusion the anterior arch length is established
Primary Incisors
Problems with replacement: Appliances are weak High maintenance – close monitoring req’d Frequent alterations as dentition changes Appliance may enhance caries risk
Primary Incisors
Primary Incisors
Primary Incisors
Primary Incisors
Primary Canine
Loss due to trauma or caries – rare Space maintainer: B&L vs. RPD Must be removed to accommodate lateral No space maintainer: Midline shift Lingual collapse in mandible
Premature loss of primary molars
Band-loop space maintainer
Indications: Unilateral loss of the 1 st eruption of the 1 st primary molar before permanent molar Unilateral loss of the 1 st eruption of the 1 st or 2 nd primary molar after permanent molar Bilateral loss of the 1 st primary molars before eruption of the permanent incisors and 1 st permanent molars Bilateral loss of the 2 nd eruption of the 1 st primary molars after permanent molar
Early loss of the 1 st primary molar
Early loss of the 2 nd primary molar
Other indications
Deflection of succedaneous tooth
Band-loop space maintainer
FABRICATION & DESIGN
Band-loop fabrication
Technique: Properly fitting band on abutment tooth (pg. 389 – Pinkham) Segmental impression (compound/alginate) Remove band from tooth & secure in impression Create working model
Band-loop fabrication
Sectional impression tray Green or red compound
Band-loop fabrication
Band-loop fabrication
Band-loop fabrication
Band-loop design
Loop should be wide enough bu-li to allow eruption of bicuspid (8 mm) Loop should not restrict physiologic movement of adjacent teeth (eg. lateral movement of primary canine)
Band-loop design
Loop should not impinge on soft tissue Loop should be in close approximation to ridge
Band-loop cementation
Apply floss ligature Try-in / seat band completely Loop should contact abutment below contact point No soft tissue impingement Cementation in properly isolated, dry field Check/adjust occlusion
Try it in first!
Loop impingement
Loop impingement
Loop impingement
Lingual arch
Lingual arch
Indications: Bilateral single or multiple tooth loss in mandible Not recommended when primary incisors still present
Lingual arch
Lingual arch design
Archwire should rest on cingulae of incisors 1-1.5 mm above gingival margin Removable vs. soldered
Lingual arch design
Solder joint should be in mid-third and parallel to band Wilson loops Archwire should be below plane of occlusion posteriorly
Lingual arch fabrication
Fit molar bands Compound/alginate impression – accurate especially in lingual sulcus & lower incisor area
Lingual arch fabrication
Secure bands in impression … …create working model
Lingual arch cementation
Check for passivity on the model and in the mouth before cementation Archwire should be in contact with lower incisor cingulae
Lingual arch cementation
Dry field GI or polycarboxylate cement No soft tissue impingement
Transpalatal arch
Transpalatal arch
Rarely recommended for bilateral tooth loss in maxilla Can prevent mesio-palatal rotation of palatal root of Mx 1 st permanent molar but allows mesial tipping of molars & space loss
Transpalatal arch
May have an indication for use when one side of the arch is intact but several primary teeth are missing contralaterally Some designs incorporate omega loop: when active can prevent bodily movement of molars
Nance arch
Nance arch
Used commonly in maxilla for bilateral tooth loss Incorporates acrylic button in contact with palate to prevent molars from tipping Can be very unhygenic
Nance arch
Nance arch fabrication
Bands fitted on molars Mx impression in compound/alginate Working model
Nance arch fabrication
Archwire will traverse the palatal vault
Nance arch fabrication
Adapted archwire is soldered to bands Acrylic button is added to embed the wire
Nance arch fabrication
Completed arch ready for try-in and cementation Ensure acrylic button in firm contact with palate
Crown-loop space maintainer
Crown-loop space maintainer
Indications: As for band-loop Abutment tooth requires full coverage SSC due to multi-surface caries or pulp treatment
Crown-loop fabrication
Abutment tooth prepared for SSC Properly contoured SSC seated, but not cemented Compound impression SSC placed into impression Working model Another SSC fitted and cemented with temporary cement
Crown-loop space maintainer
Crown-loop space maintainer
Crown-loop space maintainer
Crown-loop cementation
Temporary SSC removed, under LA if necessary Try-in crown-loop to verify loop contours Cementation in dry field
Crown-loop space maintainer
Disadvantages: If solder joint fails, there is no way to repair the appliance without entire re-make Cost is higher (extra SSC)
Band-loop over SSC
Band can be fitted over SSC as alternative to crown loop
Bonded space maintainer
Difficult to retain due to shearing forces of occlusion Flexure in function will de-bond Difficult to adjust
Removable appliances
Indicated for mulitple primary tooth loss when no suitable abutment teeth exist Need to restore occlusal function over longer span Clasping difficult for primary teeth therefore retention a problem Compliance issues
Removable appliances
INTRA-ALVEOLAR SPACE MAINTENANCE
D362/QP362 Division of Orthodontics and Paediatric Dentistry 2004-2005 Karen M. Campbell, DDS
Premature loss of the 2 nd primary molar
If the 1 st permanent molar is erupted, can use conventional B & L from 6 to D
Premature loss of the 2 nd primary molar
Band & loop from D to 6 Difficult to band D’s
Indications for intra-alveolar space maintenance
Premature loss of the 2 nd primary molar
prior
to the eruption of the 1 st permanent molar
Contraindications
Medically compromised: Cardiac patients requiring SBE prophylaxis Immunosuppression Chemotherapy/radiation therapy, pre-BMT Demonstrated lack of commitment to follow-up
Distal Shoe
Provides a guiding plane for the eruption of the 1 st permanent molar
Dentist’s responsibility
Mark on the working model the distal terminus of the appliance
Dentist’s responsibility
Provide measurement from radiograph Mark depth of shoe with cut on model Shoe should be 1 mm below mes marginal ridge of the 1 st permanent molar
Completed appliance
Immediate insertion
Follows extraction – can better visualize placement of shoe Area already anesthetized eliminates potential for 1 st permanent molar drift
Cemented appliance
Crown with distal shoe
D prepared for SSC; E to be extracted at later appt
Crown with distal shoe
Segmental impression with crown inserted
Crown with distal shoe
Tooth temporized with SSC
Crown with distal shoe
Crown with distal shoe
Extraction of the E and preparation for cementation
Crown with distal shoe
Cementation Confirmation by radiograph
Following eruption of the 1 st permanent molar
Distal shoe no longer appropriate – 1 st permanent molar may tip mesially above shoe Parents must be aware of need for second appliance from the beginning Conventional B & L or lingual arch may be required
Drawbacks of the appliance
Can only replace a single tooth due to its cantilever design Inherent lack of strength Cannot restore occlusal function D’s are very difficult to fit bands Epithelium perforated in area of distal shoe