Resin-modified Glass Ionomer Restorations Research Articles

5-Year Clinical Performance of Resin Composite versus Resin Modified Glass Ionomer Restorative System in Non-Carious Cervical Lesions

Clinical Relevance A long-term evaluation of the materials' behavior is relevant for Class V restorations in which clinical performance is particularly challenging.

Comparison of shear bond strength of resin-modified glass ionomer and composite resin to three pulp capping agents.

Background and aims. Present study was designed to compare the bonding strength of resin-modified glass ionomer (RMGI) and composite resin to mineral trioxide aggregate (MTA), MTA mixed with Na2HPO4 (NAMTA), and calcium-enriched mixture (CEM). Materials and methods. Thirty specimens of each CEM, NAMTA, and MTA were prepared. Composite and RMGI restorations were then placed on the samples (15 samples in six subgroups). Shear bond strength was assessed using universal testing machine. Data were analyzed with two-way ANOVA and post-hoc Tukey test. To compare the bond strength in subgroups, one-away ANOVA was applied. Significance level was set at P < 0.05. Results. Bond strength was significantly higher to composite samples compared to RMGI samples (p<0.001). The difference in bond strength of composite samples between MTA and CEM subgroups (P=0.026) as well as MTA and NAMTA subgroups (P= 0.019) was significant, but the difference between NAMTA and CEM subgroups (P=0.56) was not significant. The differences in bond strength in subgroups of RMGI group were not significant (P>0.05). Conclusion. Regarding shear bond strength to the tested substrates, composite was shown to be superior to RMGI. The bond of resin composite to MTA was weaker than that to CEM and NAMTA.

Effect of Pre-Treatment Agents on Bond Strength of Conventional and Resin-Modified Glass Ionomer Restoratives to Dentin

이 연구의 목적은 수종의 판매 중인 전 처리제를 상아질에 전 처리한 후 글라스 아이오노머 수복재료를 접착시켜 접착강도를 측정함으로써, 상아질 전 처리가 접착강도에 어떤 영향을 미치는지 알아보고자 함이었다. 접착강도를 측정하기 전에 각 재료의 pH를 측정하였다. 전통적인 글라스 아이오노머(Fuji Ⅱ, GC)와 레진 강화형 글라스 아이오노머(Fujii Ⅱ LC Improved)의 액 성분의 pH도 같이 측정하여 비교하였다. 전 처리제(Dentin Conditioner, GC; Fuji Plus Conditioner, GC; Uni-Etch, Bisco)로 처리한 상아질에 Fuji Ⅱ와 Fuji Ⅱ LC를 접착시킨 후 전단접착강도를 측정하였고, 표면을 SEM으로 관잘하였다. 이때 32% 인산 겔인 Uni-Etch는 각각 5초와 15초 상아질에 적용하였다. 상아질-아이오노머 계면을 SEM으로 관찰하였고 EDS로 선 스캔을 하여 탈회의 양상을 관찰하였다, 실험 결과, 평균 pH는 0.02~1.87의 범위였고, 접착강도는 평균 3,21~10.9의 범위를 나타내었다, 열 순환 전에는 Fuji Plus Conditioner로 처리된 상아질에 접착된 Fuji Ⅱ Improved가 가장 높은 유의한 접착강도를 나타내었다. Uni-Etch를 상아질에 15초 처리했을 때, 상아질 접착강도의 향상은 관찰되지 않았다. Dentin Conditioner와 GC Fuji Plus Conditioner로 처리된 상아질의 SEM상은 서로 유사한 양상을 나타냈다. Uni-Etch는 도말층을 완전히 제거하고 상아세관을 개방시켰다. EDS 선 스캔 결과 각 전 처리제와 조건에 따라 다른 탈회 깊이를 나타내었는데, Uni-Etch가 가장 깊은 탈회 깊이를 나타내었다. 결론적으로, 글라스 아이오노머 수복재료는 상아질에 대해 전처리 없이도 양호한 접착을 형성할 수 있지만, 전 처리제로 전 처리를 하게 되면 접착강도의 증가가 기대된다.

Connective tissue graft plus resin-modified glass ionomer restoration for the treatment of gingival recession associated with non-carious cervical lesions: microbiological and immunological results

It was previously reported the clinical results of placing subgingival resin-modified glass ionomer restoration for treatment of gingival recession associated with non-carious cervical lesions. The aim of this study was to evaluate the influence of this treatment on the subgingival biofilm and gingival crevicular fluid (GCF) inflammatory markers. Thirty-four patients presenting the combined defect were selected. The defects were treated with either connective tissue graft plus modified glass ionomer restoration (CTG+R) or with connective tissue graft only (CTG). Evaluation included bleeding on probing and probing depth, 5 different bacteria targets in the subgingival plaque assessed at baseline, 45, and 180days post treatments, and 9 inflammatory mediators were also assessed in the GCF. The levels of each target bacterium were similar during the entire period of evaluation (p > 0.05), both within and between groups. The highest levels among the studied species were observed for the bacterium associated with periodontal health. Additionally, the levels of all cyto/chemokines analyzed were not statistically different between groups (p > 0.05). Within the limits of the present study, it can be concluded that the presence of subgingival restoration may not interfere with the subgingival microflora and with GCF inflammatory markers analyzed. This approach usually leads to the placement of a subgingival restoration. There is a lack of information about the microbiological and immunological effects of this procedure. The results suggest that this combined approach may be considered as a treatment option for the lesion included in this study.

Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives

Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI) restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. 98 rectangular cavities (2.5×3×1.5 mm) were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14). The cavities in groups 1, 2 and 3 were restored using a composite resin (APX). The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC). Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch) were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05). There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05). The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

A novel hyperbranched poly(acrylic acid) for improved resin-modified glass-ionomer restoratives

Objective The objective of this study was to synthesize and characterize novel hyperbranched poly(acrylic acid)s via atom-transfer radical polymerization (ATRP) technique and tether the photo-curable methacrylate onto the poly(acrylic acid), use these polymers to formulate the resin-modified glass-ionomer cements, and evaluate the mechanical strengths of the formed cements. Materials and methods The hyperbranched poly(acrylic acid)s were synthesized using a self-condensing vinyl polymerization initiator via ATRP. The effects of the concentrations of both catalyst and initiator on molecular weight (MW) and degree of branching (DB) were studied. Compressive, diametral tensile as well as flexural strengths, fracture toughness, hardness and wear-resistance of the experimental cement were evaluated and compared to those of Fuji II LC cement. The specimens were conditioned in distilled water at 37 °C for 24 h prior to testing. Results The concentrations of both catalyst and initiator had significant effects on MW and DB of the synthesized polymers. The concentration of the initiator also significantly affected both CS and DTS values of the cement. The experimental cement showed significantly higher mechanical properties, i.e., 53% in CS, 50% in compressive modulus, 125% in DTS, 95% in FS, 21% in FT and 96% in KHN, higher than Fuji II LC. The experimental cement was only 5.4% of abrasive and 6.4% attritional wear depths of Fuji II LC. Conclusions This study developed a novel resin-modified glass-ionomer cement system composed of newly synthesized hyperbranched poly(acrylic acid)s. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations.

Root Coverage in an HIV‐Positive Individual: Combined Use of a Lateral Sliding Flap and Resin‐Modified Glass Ionomer for the Management of an Isolated Severe Recession Defect

Gingival recession is a frequent clinical finding in the general population. Exposed root surfaces are more likely to develop root sensitivity and root caries and pose esthetic concerns for the patient. Most root coverage procedures have been described on non-restored root surfaces. Limited data are available that describe root coverage procedures on restored root surfaces. To our knowledge, this is the first case report in which a severe recession defect and its associated carious lesion were managed using the combination of a lateral sliding flap and a resin-modified glass ionomer restoration in an HIV-positive individual. A 53-year-old male patient with a 25-year history of HIV infection presented for comprehensive care. The facial surface of tooth #22 had a fractured composite restoration, recurrent decay, and a Miller Class III recession defect. The lesion was restored with resin-modified glass ionomer and root coverage was obtained by a lateral sliding flap mobilized from the adjacent edentulous ridge. After 8 weeks, surgical access was used to correct a previously undetected void in the restoration. Uneventful healing was observed at the 1-, 4-, 8-, 10-, 12-, and 24-week postoperative visits. Root coverage of 5 mm along with a 2-mm band of keratinized tissue was obtained at 24 weeks. The gingiva displayed no signs of inflammation and was tightly adapted to the root surface with minimal probing depths circumferentially. Successful root coverage was obtained on a resin-modified glass ionomer-restored surface in an HIV-positive individual.

Clinical evaluations of resin-modified glass-ionomer restorations

This paper collates some of the existing data on the clinical evaluations of resin-modified glass-ionomer cements (RMGICs) since their introduction two decades ago. The relevant literature was considered and data reviewed under the headings of retention, marginal characteristics, material deterioration, secondary caries, color stability, as well as pulpal and biological effects. The retention for RMGICs is generally good, with an annual failure rate over 13 years reported as being under 3%. However, more data is required on their performance in carious situations. Regarding marginal characteristics, they exhibit margins that are likely to deteriorate over time. From the limited data on the surface characteristics, they appear to exhibit some wear and loss of anatomic form, particularly in the mid to long term. Despite the fact that the studies reviewed for secondary caries varied in the initial caries status of lesions restored, the overwhelming conclusion is that this does not seem to be a problem. While their initial color match may be favorable, it appears that they change over time and may not be color stable. In the absence of more clinical data, it is difficult to draw conclusions on the pulpal and biological effects. The existing information primarily reports postoperative sensitivity, which fortunately does not seem to be an issue with RMGICs, and limited histopathology of the pulp, with mixed opinions. The RMGICs appear to perform well in terms of retention, and secondary caries as well as postoperative sensitivity are not a problem. However, this is not necessarily true of their marginal characteristics, surface properties and color stability. More and long-term clinical research is required to establish compelling evidence of their behavior, particularly in terms of retention in carious cavities, surface properties and biological effects.

Connective tissue graft plus resin‐modified glass ionomer restoration for the treatment of gingival recession associated with non‐carious cervical lesion: a randomized‐controlled clinical trial

The aim of this clinical study was to evaluate the treatment of gingival recession, associated with non-carious cervical lesions by a connective tissue graft (CTG) alone, or in combination with a resin-modified glass ionomer restoration (CTG+R). Forty patients presenting Miller Class I buccal gingival recessions, associated with non-carious cervical lesions, were selected. The defects were randomly assigned to receive either CTG or CTG+R. Bleeding on probing (BOP), probing depth (PD), relative gingival recession (RGR), clinical attachment level (CAL) and cervical lesion height (CLH) coverage were measured at baseline and 45 days, and 2, 3 and 6 months after treatment. Both groups showed statistically significant gains in CAL and soft tissue coverage. The differences between groups were not statistically significant in BOP, PD, RGR and CAL, after 6 months. The percentages of CLH covered were 74.88 +/- 8.66% for CTG and 70.76 +/- 9.81% for CTG+R (p>0.05). The estimated root coverage was 91.91 +/- 17.76% for CTG and 88.64 +/- 11.9% for CTG+R (p>0.05). Within the limits of the present study, it can be concluded that both procedures provide comparable soft tissue coverage. The presence of the glass ionomer restoration may not prevent the root coverage achieved by CTG.

Hardness of Three Resin‐Modified Glass‐Ionomer Restorative Materials as a Function of Depth and Time

The polymerization of bulk-placed resin-modified glass-ionomer (RMGI) restoratives is compromised when penetration of the curing light is limited because of the materials' thickness. It is unknown if additional post light-curing resin polymerization and/or glass-ionomer setting occurs over time to ensure adequate polymerization. The primary objective was to evaluate the depth of cure of various thicknesses of RMGI restorative products over 1 year using Knoop hardness (KH) testing. The materials were placed in Delrin molds having an internal diameter of 5.0 mm and heights of 2, 3, 4, and 5 mm and were photopolymerized with a halogen light-curing unit. Five specimens of each depth were prepared for each time period evaluated. Specimens were stored in darkness at 37 +/- 2 degrees C and 98 +/- 2% humidity until being tested at 24 hours, 1 week, and 1, 3, 6, 9, and 12 months after fabrication. Mean KH values were calculated for the bottom and top surfaces of each thickness group and used to determine bottom/top hardness ratios. Data were compared using two-way analysis of variance (factors of time, thickness) at a 0.05 significance level with Scheffé's post hoc analysis, where required. The materials had relatively stable top surface KH, which permitted valid assessment of changes in bottom surface KH over time. The bottom surface KH of some RMGIs changed significantly over time (p < 0.001), but degrees of change were material dependent. Certain RMGIs demonstrated a potential for statistically significant post light-activation hardening; however, that too was material dependent. As compared with top surface KH, deeper layers of the thicker RMGI specimens consistently failed to achieve an adequate degree of polymerization. Although certain RMGI materials demonstrate a potential for post light-activation chemically initiated resin polymerization and/or polyalkenoate acid/base reaction, these reactions may not be sufficient to ensure that the material is adequately polymerized for long-term success. This is particularly true when RMGI materials are placed in thicker layers where curing light penetration may be compromised. RMGI materials should not be placed in bulk but photopolymerized in layers to ensure adequate light activation. The results of this study suggest that Photac-Fil Quick be placed in layers no thicker than 2 mm while Fuji II LC and Vitremer may be placed in layers up to 3 mm in thickness.

Cervical restoration and the amount of soft tissue coverage achieved by coronally advanced flap: A 2‐year follow‐up randomized‐controlled clinical trial

The aim of this study was to evaluate the 2-year follow-up success of the treatment of gingival recession associated with non-carious cervical lesions by a coronally advanced flap (CAF) alone or in combination with a resin-modified glass ionomer restoration (CAF+R). Sixteen patients with bilateral Miller Class I buccal gingival recessions, associated with non-carious cervical lesions, were selected. The defects received either CAF or CAF+R. Bleeding on probing (BOP), probing depth (PD), relative gingival recession (RGR), clinical attachment level (CAL) and cervical lesion height (CLH) coverage were measured at the baseline and 6, 12 and 24 months after the treatment. Both groups showed statistically significant gains in CAL and soft tissue coverage. The differences between groups were not statistically significant in BOP, PD, RGR and CAL, after 2 years. The percentages of CLH covered were 51.57 +/- 17.2% for CAF+R and 53.87 +/- 12.6% for CAF (p>0.05). The estimated root coverage was 80.37 +/- 25.44% for CAF+R and 83.46 +/- 20.79% for CAF (p>0.05). Within the limits of the present study, it can be concluded that both procedures provide acceptable soft tissue coverage after 2 years, with no significant differences between the two approaches.

Effect of Postoperative Bleaching on Marginal Leakage of Resin Composite and Resin-Modified Glass Ionomer Restorations at Different Delayed Periods of Exposure to Carbamide Peroxide

AbstractAimTo evaluate the effect of dental bleaching with carbamide peroxide at different exposure times on the microleakage of resin composite and resin-modified glass ionomer restorations after placement in extracted human teeth.Methods and Materials120 Class V cavity preparations were placed at the cementoenamel junction (CEJ) of human teeth. Half of the cavities were restored with Filtek P60 resin composite(C) and the other half were restored with Fuji II LC resin-modified glass ionomer (G). Each group was randomly divided into four subgroups (n=15). Groups C1 and G1 were not bleached and stored in artificial saliva at 37°C to serve as control groups, while in Groups C2 and G2, C3 and G3, and C4 and G4 specimens were exposed to a 15% carbamide peroxide gel for one day, one week, and two weeks, respectively, following the placement of restorations. Microleakage was assessed using the dye penetration method. Data were analyzed using the Kruskal-Wallis and Wilcoxon tests (p=0.05).ResultsThe Kruskal-Wallis test showed no significant difference among all groups of composite or glass ionomer restorations with either enamel or dentinal margins with regard to microleakage (p&gt;0.05). The Wilcoxon test revealed more marginal leakage in the enamel/ glass ionomer margins than the enamel/ composite margins (p&lt;0.05). In comparisons within each group, the Wilcoxon test showed there was more microleakage in dentinal margins of composite restorations than in the enamel margins in the test groups (p&lt;0.05). The dentinal margins of the glass ionomer in control groups showed more leakage than the enamel margins, but after the bleaching procedure all experimental groups showed statistically similar microleakage in both the enamel and dentinal margins (p&gt;0.05).ConclusionsPostoperative bleaching with carbamide peroxide could increase microleakage in the dentinal margins of composite and the enamel margins of resin-modified glass ionomer restorations.Clinical SignificanceRebonding of resin composite restorations should be considered following bleaching with 15% carbamide peroxide in order to reseal the margins. Resin-modified glass ionomer is not suitable as a filling material before bleaching because of its susceptibility to increased microleakage.CitationMoosavi H, Ghavamnasiri M, Manari V. Effect of Postoperative Bleaching on Marginal Leakage of Resin Composite and Resin-Modified Glass Ionomer Restorations at Different Delayed Periods of Exposure to Carbamide Peroxide. J Contemp Dent Pract [Internet]. 2009 Nov; 10(6):009-016. Available from: http://www.thejcdp. com/journal/view/volume10-issue6-moosavi.

Effect of Postoperative Bleaching on Marginal Leakage of Resin Composite and Resin-Modified Glass Ionomer Restorations at Different Delayed Periods of Exposure to Carbamide Peroxide

To evaluate the effect of dental bleaching with carbamide peroxide at different exposure times on the microleakage of resin composite and resin-modified glass ionomer restorations after placement in extracted human teeth. 120 Class V cavity preparations were placed at the cementoenamel junction (CEJ) of human teeth. Half of the cavities were restored with Filtek P60 resin composite (C) and the other half were restored with Fuji II LC resin-modified glass ionomer (G). Each group was randomly divided into four subgroups (n=15). Groups C1 and G1 were not bleached and stored in artificial saliva at 37 degrees C to serve as control groups, while in Groups C2 and G2, C3 and G3, and C4 and G4 specimens were exposed to a 15% carbamide peroxide gel for one day, one week, and two weeks, respectively, following the placement of restorations. Microleakage was assessed using the dye penetration method. Data were analyzed using the Kruskal-Wallis and Wilcoxon tests (p=0.05). The Kruskal-Wallis test showed no significant difference among all groups of composite or glass ionomer restorations with either enamel or dentinal margins with regard to microleakage (p>0.05). The Wilcoxon test revealed more marginal leakage in the enamel/glass ionomer margins than the enamel/composite margins (p<0.05). In comparisons within each group, the Wilcoxon test showed there was more microleakage in dentinal margins of composite restorations than in the enamel margins in the test groups (p<0.05). The dentinal margins of the glass ionomer in control groups showed more leakage than the enamel margins, but after the bleaching procedure all experimental groups showed statistically similar microleakage in both the enamel and dentinal margins (p>0.05). Postoperative bleaching with carbamide peroxide could increase microleakage in the dentinal margins of composite and the enamel margins of resin-modified glass ionomer restorations. Rebonding of resin composite restorations should be considered following bleaching with 15% carbamide peroxide in order to reseal the margins. Resin-modified glass ionomer is not suitable as a filling material before bleaching because of its susceptibility to increased microleakage.

Coronally Positioned Flap Plus Resin‐Modified Glass Ionomer Restoration for the Treatment of Gingival Recession Associated With Non‐Carious Cervical Lesions: A Randomized Controlled Clinical Trial

The aim of this randomized clinical trial was to evaluate the treatment of gingival recession associated with non-carious cervical lesions by a coronally advanced flap alone (CAF) or in combination with a resin-modified glass ionomer restoration (CAF+R). Nineteen subjects with bilateral Miller Class I buccal gingival recessions associated with non-carious cervical lesions were selected. The recessions were assigned randomly to receive CAF or CAF+R. Bleeding on probing (BOP), probing depth (PD), relative gingival recession (RGR), clinical attachment level (CAL), non-carious cervical lesion height (CLH), and dentin sensitivity (DS) were measured at baseline; 45 days; and 2, 3, and 6 months postoperatively. Keratinized tissue width (KTW) and keratinized tissue thickness (KTT) were measured at baseline and 6 months. The height of the non-carious cervical lesion located on the root and crown were estimated, allowing calculation of root coverage. Both groups showed statistically significant gains in CAL and soft tissue coverage. The differences between groups were not statistically significant for BOP, PD, RGR, CAL, KTW, and KTT after 6 months. The percentages of CLH covered were 56.14% +/- 11.74% for CAF+R and 59.78% +/- 11.11% for CAF (P >0.05). The root and crown surfaces affected by the non-carious cervical lesion were 1.67 +/- 0.31 mm and 0.96 +/- 0.29 mm, respectively, for CAF+R and 1.59 +/- 0.37 mm and 1.01 +/- 0.33 mm, respectively, for CAF. The estimated root coverage was 88.02% +/- 19.45% for CAF+R and 97.48% +/- 15.36% for CAF (P >0.05). CAF+R reduced DS significantly compared to CAF (P <0.05). Both procedures provided similar soft tissue coverage after 6 months. Despite the fact that a greater reduction in DS was observed after CAF+R, longitudinal observations are necessary to confirm these results.

Resin-Modified Glass Ionomer Restorations may have Better Long-term Outcomes than Conventional Glass Ionomer Restorations in Primary Teeth

Resin-modified and conventional glass ionomer restorations in primary teeth: 8-year results. Qvist et al. J Dent 2004;32(4):285-94 . Ib The authors compared the longevity and cariostatic effects of resin-modified and conventional glass ionomer restorations in primary teeth. Governmental grants and industry (ESPE). Randomized controlled trial

Periodontal Surgery and Glass Ionomer Restoration in the Treatment of Gingival Recession Associated With a Non‐Carious Cervical Lesion: Report of Three Cases

Buccal gingival recession is a prevalent problem in populations with a high standard of oral hygiene and is very often associated with a non-carious cervical lesion, complicating treatment. The purpose of this report is to show three cases treated by an integrated periodontal and restorative dentistry approach. Three patients with Miller Class I gingival recessions associated with non-carious cervical lesions were enrolled for treatment. One patient received a coronally positioned flap and a resin-modified glass ionomer restoration, and two patients were treated with a coronally positioned flap, resin-modified glass ionomer restoration, and connective tissue graft. Probing depth (PD), relative gingival recession (RGR), and clinical attachment level (CAL) were measured at baseline and at 6 and 8 months after surgery. After the healing period, all patients showed CAL gain and reduction in RGR. No difference was observed on PDs compared to baseline. No signs of gingival inflammation or bleeding on probing were seen. The patients were satisfied with the final esthetics and had no more dentin hypersensitivity. This report indicates that teeth with Miller Class I gingival recessions associated with non-carious cervical lesions can be successfully treated by an integrated periodontal and restorative dentistry approach; however, longitudinal randomized controlled clinical trials must be performed to support this approach.

5-year Clinical Performance of Resin Composite Versus Resin Modified Glass Ionomer Restorative System in Non-carious Cervical Lesions

To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions. One operator placed 70 restorations (35 resin modified glass ionomer restorations and 35 resin composite restorations) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by 2 independent examiners, using modified USPHS criteria at baseline and 6, 12, 24 and 60 months. Twenty-two patients were available for recall after 5 years (73.3% recall rate) and 55 out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (kappa > or = 0.85). Sixteen composite restorations were dislodged (51.5% retention) and 1 ionomer restoration was lost (96.4% retention). The McNemar test detected significant differences in resin composite restorations between baseline and 5-year recall for marginal integrity (p<0.001) and retention (p=0.004). For resin modified glass ionomer restorations, no significant differences were identified for all criteria (p>0.05). When comparing both materials, the Fisher exact test pointed out significant differences in retention (p=0.002) after 5 years of clinical service. After 5 years of evaluation, the clinical performance of resin modified glass ionomer restorations was superior to resin composite restorations.

Effect of Thermocycling on Interfacial Gap-formation in Class V Cavities and Mechanical Properties of Spherical Silica Filler Addition to Resin-modified Glass Ionomer Restorations

The effects of thermocycling at 20,000 cycles and addition of silanized spherical silica filler (SF) on resin-modified glass ionomer cement (RMGIC) restorations were investigated. A RMGIC added with an untreated spherical silica filler (UF) was used as a comparison. Marginal gaps in Class V tooth cavities, compressive strength, diametral tensile strength, flexural strength, and shear bond strengths to enamel and dentin were examined. All thermocycled samples showed decreased frequency of marginal gap formation as compared to the 24-hour samples, with reduction of 73% to 95%. At the immediate condition, after 24 hours, and after thermocycling, the addition of 10 wt% SF yielded the most favorable results in terms of marginal gap formation in Class V cavities, compressive strength, flexural strength, and shear bond strength to enamel. Diametral tensile strength and flexural strength were also increased significantly by the addition of 5 wt% SF. Further, shear bond strength tests showed that the addition of SF had no effect on bonding capability to enamel and dentin.

Effect of smear layer on root demineralization adjacent to resin-modified glass ionomer.

The cariostatic effect of resin-modified glass ionomer (RMGI) on secondary root caries is well-documented. However, this beneficial effect may be dependent upon the mode of cavity surface treatment. To investigate this relationship, we studied 4 cavity surface treatments prior to the placement of RMGI: no treatment (None), polyacrylic acid (PAA), phosphoric acid (H(3)PO(4)), and Scotchbond Multi-Purpose adhesive (SMP) as a control. Specimens were aged for two weeks in synthetic saliva, thermocycled, and subjected to an artificial caries challenge (pH 4.4). Polarized light microscopy (PLM) and microradiography (MRG) showed significantly less demineralization with the H(3)PO(4) cavity surface treatment as revealed by ANOVA and Tukey's multiple comparisons (p < or = 0.05). Dentin fluoride profiles determined by electron probe microanalysis (EPMA) supported PLM and MRG findings. It may be concluded that removal of the smear layer with phosphoric acid provides significantly enhanced resistance to secondary root caries formation adjacent to RMGI restorations.

Effect of various surface protections on the margin microleakage of resin-modified glass ionomer cements

Statement of Problem. Because conventional glass ionomer cements are moisture sensitive, a surface coating is recommended during the initial setting stage. It is unknown whether resin-modified glass ionomer cements also need surface protection. Purpose. This study investigated the effect of various surface protections on microleakage with Class V resin-modified glass ionomer restorations. Material and Methods. Forty extracted molars with buccal and lingual Class V cavity preparations were restored with a resin-modified glass ionomer (Fuji II LC). The occlusal margin of each restoration was on enamel and the cervical margin on dentin. After immediate finishing and polishing, the teeth were divided into 4 groups according to the following surface protection treatments: group I, unprotected; group II, Fuji varnish; group III, resin adhesive; and group IV, acid etching and resin adhesive. After these procedures, all teeth were stored in isotonic saline for 24 hours, thermocycled 1500 times at 5°C to 60°C, and soaked in dye solution for 24 hours. The teeth then were longitudinally sectioned and observed under a stereomicroscope. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney tests (P<.05) Results. None of the 4 groups demonstrated complete margin sealing at either the occlusal or cervical margins. Groups II and III displayed the least microleakage at cervical margins; a significant difference existed between groups I and III (P=.034). Compared with the other 3 groups, group IV showed significantly greater microleakage at the cervical margins. Conclusion. Although resin-modified glass ionomers can be finished immediately, they remain moisture sensitive. Within the limitations of this study, the results suggest that resin adhesive should be used as a surface protection to reduce margin microleakage of resin-modified glass ionomer restorations. (J Prosthet Dent 2001;86:309-14.)