ABSTRACT
PURPOSE: To evaluate the durability of a modified open-sandwich restoration utilizing a resin-modified glass ionomer cement (RMGIC) in large cavities. METHODS: 268, mostly extensive, Class II Vitremer/Z100 restorations were placed in 151 patients. 47% of the restorations were placed in patients considered as caries-risk patients. Six experimental groups, differing from each other in thickness of RMGIC layer and preconditioning, were evaluated at baseline and annually during 6-7 years according to modified USPHS criteria. RESULTS: After 6 years, 220 restorations were evaluated. 42 failures (19%) were observed. The most frequent reasons for failure were material fracture (n = 11), tooth fractures (n = 9) and secondary caries (n = 10). Non-acceptable proximal dissolution of the RMGIC was seen in six restorations. Significantly more failures, but similar dissolution of the RMGIC, were recorded in high caries risk patients. No differences were seen between the experimental groups or between restorations with thick or thin RMGIC layer. 160 restorations were also evaluated at 7 years. Another 13 failures were observed, eight with non-acceptable dissolution, three secondary caries and two fractures. It can be concluded that the modified open sandwich restoration showed an acceptable durability for the extensive restorations evaluated. An accelerating dissolution of the RMGIC was observed at the end of the study.
Subject(s)
Cariostatic Agents , Composite Resins , Dental Restoration Failure , Dental Restoration, Permanent/methods , Glass Ionomer Cements , Acid Etching, Dental/methods , Adolescent , Adult , Aged , Aged, 80 and over , Dental Caries/etiology , Dental Marginal Adaptation , Dental Restoration, Permanent/adverse effects , Dentin-Bonding Agents , Female , Humans , Life Tables , Logistic Models , Longitudinal Studies , Male , Middle Aged , Resin Cements , Survival AnalysisABSTRACT
The sandwich technique with resin-modified glass ionomer cement (RMGIC) has been proposed to relieve the contraction stresses of direct resin composite (RC) restorations. The aim of this study was to evaluate the interfacial adaptation to enamel and dentin of modified Class II open RMGIC/RC sandwich restorations and the influence of different light curing techniques and matrix bands. Forty box-shaped Class II fillings were placed in vivo in premolars scheduled for extraction after one month. In groups I and II, a metal matrix was used; RC was inserted with horizontal (group I) and diagonal (group II) increments and cured with indirect/direct light. Group III was performed as group II, but a transparent matrix was used. Group IV was as group II, but with a separating liner between RMGIC and RC. Group V was a closed sandwich restoration. Interfacial quality was studied using SEM replica technique. Gap-free interfacial adaptation to enamel was observed for RMGIC in 70%, for RC in 70% and to dentin for RMGIC in 81%, for RC in 56%. No significant differences were seen between the experimental groups. At the cervical margins, RMGIC showed significantly better adaptation to enamel than RC, 74% and 42%, respectively. In conclusion, the investigated restorations showed a high percentage of gap-free interfacial adaptation in vivo. Interfacial adaptation to dentin and to cervical enamel was significantly better for RMGIC than for RC.
