209 - Retentive Strength of Bands Cemented to Altered Pediatric Crowns

Purpose: To evaluate bond strength of stainless steel (SS) bands cemented to zirconia pediatric crowns (ZRCs) with surface alterations.

Methods: Lower second mandibular ZRCs (Kinder Krown) and SS crowns (3M) were mounted on acrylic crown preparation dies.  The crowns were divided into 5 groups (n=10):  1) no preparation of ZRC surface (ZR-C, control); 2) ZRC roughened with diamond bur (ZR-R); 3) ZRC primed with Z-prime (zirconia-alumina-metal primer, BISCO) (ZR-P); 4) no preparation of SSC (SSC-C); and 5) SSC primed with Z-prime (SSC-P). Mandibular SS bands (space maintainer, DeNovo) were cemented with RelyX Luting Plus cement (3M) on each crown.  All samples were stored at 37^oC for 24 hours prior to testing. The arm attachment of each space maintainer was pushed downward in a universal testing machine (Instron) at a rate of 1mm/min until the band dislodged. Interfaces of all dislodged bands were inspected under a stereomicroscope.

Results: Maximum dislodging loads in Newtons (mean ± standard deviation) for the 5 groups were: ZR-C (200 ± 20), ZR-R (201 ± 63), ZR-P (189 ± 27), SSC-C (210 ± 26), and SSC-P (196 ± 21).

No significant differences were found among the groups (P=.7527). Most debonding occurred at the band-cement interface: ZR-C (100%, N=10), ZR-R (100%, N=10), ZR-P (100%, N=10), SSC-C (90%, N=9), and SSC-P (100%, N=10).

Conclusions:   Altering a zirconia or stainless steel crown surface with a diamond bur or applying Z-prime to the crown surface and band did not improve retention of a band cemented with RelyX Luting Plus. 

 


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