A 6-year clinical evaluation of Class I poly-acid modified resin composite/resin composite laminate restorations cured with a two-step curing technique.
OBJECTIVE
Polymerization shrinkage is still one of the main disadvantages of resin composite restorations (RC). Especially in cavities with a high C-factor, debonding can occur. A laminate restoration including a base with a more elastic behavior might result in a better adaptation. The purpose of this study was to evaluate the durability of a combination of two techniques suggested to counter the stress formation in direct RC restorations in cavities with the highest C-factor.


METHODS
Each of the 29 patients received one or two pair(s) of Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite (PMRC/RC) sandwich restoration and the second a direct RC restoration. Both restorations, except for the PMRC layer, were placed with oblique layering and two-step curing technique. Ninety restorations, 23 premolar and 67 molars, were evaluated annually with slightly modified USPHS criteria during 6 years.


RESULTS
At 6 years, 41 pairs were evaluated. A cumulative failure rate of 2.4% was observed for both the RC and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one RC restoration showed non-acceptable marginal adaptation. Two cases of slight postoperative sensitivity were observed in one patient. Three restorations were partially replaced due to primary proximal caries.


CONCLUSIONS
A high durability for and no differences, were observed between both restorative techniques in Class I cavities.
Institution of Odontology, Dental Hygienist Education, Dental School Umeå, Umeå University, 901 87, Umeå, Sweden. jan.van.dijken@odont.umu.se
Jan W V
JW
van Dijken
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001641:Bicuspid; D003116:Color; D020770:Compomers / Q000528:radiation effects; D003188:Composite Resins / Q000528:radiation effects; D003737:Dental Cavity Preparation; D018772:Dental Marginal Adaptation; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods*; D004548:Elasticity; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D008963:Molar; D011108:Polymers / Q000737:chemistry; D014075:Tooth Discoloration
D020770:Compomers; D003188:Composite Resins; C088486:Dyract; D011108:Polymers; C088833:Prisma TPH resin composite