Strength of tunnel-restored teeth with different materials and marginal ridge height.
OBJECTIVE
The aim of the study was to investigate the strength of the marginal ridge of tunnel preparations with different marginal ridge heights, using different restorative materials.


METHODS
120 sound premolars were randomly divided into three groups of standardized tunnel preparations with a remaining marginal ridge height of 1.5 mm, 2.5 mm and 3.5 mm, respectively. In each tunnel group, 10 teeth were filled with all four newly developed adhesive materials that had not previously been used in tunnel preparation: Ketac Aplicap, Fuji IX, Fuji II LC and Beautifil Flow F02. The control group comprised 10 sound teeth. All teeth were subjected to incremental dynamic force testing. Remaining marginal ridge height and restoration material were the independent variables. The mean maximum energy (MEI) score was the dependent variable. Data were analyzed, using one- and two-way analysis of variance. Scheffe's test and Student's t-test were used for comparison between groups.


RESULTS
Both restorative material (P<0.0001) and remaining marginal ridge height (P<0.0001) had a statistically significant effect on the mean MEI score of tunnel-prepared teeth. At the 2.5 mm of remaining marginal ridge height, no statistically significant difference in mean MEI score existed between Beautifil Flow F02-filled tunnel-prepared teeth and sound teeth.


CONCLUSIONS
Premolars tunnel-restored with Beautifil Flow F02 at 2.5 mm distance from the marginal ridge were as strong as sound teeth.
Ji
Wei
W
Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei 430079, PR China.
Chen
Zhi
Z
Frencken
Jo E
JE
D000180:Acrylic Resins / Q000737:chemistry; D001641:Bicuspid; D003737:Dental Cavity Preparation / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D019228:Tooth Crown / Q000033:anatomy & histology*; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; C508973:Beautifil FL-Bond; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C079765:Fuji II LC cement; C439808:Fuji IX GP Fast; D005899:Glass Ionomer Cements; C424245:Ketac-Molar Aplicap; D019279:Resin Cements; D012117:Resins, Synthetic; D014867:Water; C006903:carbopol 940