The effects of cavity size and filling method on the bonding to Class I cavities.
OBJECTIVE
The effects of incremental filling technique and flowable liner on the bond strength of resin composite in different sized cavities were investigated in this study.


METHODS
Two sizes of cylindrical Class I cavities were prepared in bovine dentin (98.1 mm3 and 21.2 mm3). A light-curing resin composite (Clearfil Photocore) with a self-etching primer adhesive (Clearfil SE Bond) was used to bulk fill the cavities (C-factor 5), with and without flowable liner (Clearfil FLOW-FX) or incremental filling (2 layers, C-factor 3). As control, a 3-mm or 5-mm buildup was placed on the flat dentin surface (C-factor 0.2). After 24 h storage in 37 degrees C water, the microtensile bond strength was measured at a crosshead speed of 1 mm/min. Mode of failure in the fractured specimens was observed using a scanning electron microscope. The obtained results were statistically analyzed.


RESULTS
In large cavities, incrementally filled and lined cavities showed higher bond strength values than the bulk-filled subgroup (p < 0.05). However, in small cavities, neither the incremental technique nor flowable liner improved the bond strength.


CONCLUSIONS
Not only the filling techniques but also the cavity size affected the bond strength to the cavity floor in cylindrical Class I cavities.
He
Zhengdi
Z
Department of Restorative Sciences, Tokyo Medical and Dental University, Tokyo, Japan. hezhd0122@yahoo.co.jp
Shimada
Yasushi
Y
Sadr
Alireza
A
Ikeda
Masaomi
M
Tagami
Junji
J
D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003736:Dental Cavity Lining; D003737:Dental Cavity Preparation / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000145:classification / Q000379:methods*; D003804:Dentin / Q000473:pathology*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011109:Polymethacrylic Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
C501417:Clearfil Flow FX; C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; D019279:Resin Cements; D014867:Water; C074669:Clearfil Photo Bond