Marginal integrity of ceramic inlays luted with a self-curing resin system.

OBJECTIVE: Aim of this study was to observe the efficacy of two different composite cements on the prevention of marginal deterioration around adhesive ceramic inlay restorations, under laboratory conditions, and to test the null hypothesis that different luting procedures cannot affect sealing ability of luted inlays. METHODS: Twenty-six standardized mesio-occlusal Class II cavities were prepared in extracted posterior teeth. Class II inlays were fabricated with IPS Empress II system following the manufacturer's instructions. The samples were divided into two groups of 13 teeth each at random. Group 1: The ceramic inlays of Group 1 were luted using Excite DSC and an experimental self-curing resin cement (Multilink, Vivadent); in this group, Excite DSC was self-activated and not light-cured. Group 2: Excite DSC in combination with a dual-curing resin cement (Variolink II, Vivadent) was used (as control). In this group Excite DSC was light-cured for 20s separately, before resin cement application. The 'wet' bonding technique was followed. Three samples of each group were selected at random for SEM observations, while the other 10 samples were processed for marginal leakage. The bonding mechanism to dentin and resin cement thickness was evaluated. RESULTS: Samples of both groups showed resin tag and adhesive lateral branch formation. In Group 1 the hybrid layer was mainly uniform along the interface between dental substrates and adhesive material, and resin cement thickness was between 20 and 85 microm. At the cervical margin no gap was detected. In Group 2 the cement thickness was between 30 and 110 microm and hybrid layer formation was observed along the interface but at the cervical margin it was not always uniform and continuous. Resin tag formation was uniform in both groups. At cervical margins, 80% of Group 1 samples showed a perfect seal at the dentin-cementum margins, and 90% at enamel margins. Group 2 samples showed only 50% of cervical margins free from leakage and 80% at the occlusal enamel margins. Statistically significant differences were found at cervical margins between the two groups, while no significant differences were found at enamel site.CONCLUSIONS: It can be concluded that the self-curing adhesive-resin cement combination can properly seal Class II porcelain inlays.     

Marginal adaptation of heat-pressed glass-ceramic veneers to dentin in vitro.

The purpose of the present study was to examine the marginal adaptation of ceramic veneers to dentin at the cervical margins and to enamel at the palatoincisal margins using four dual-curing composite resin cements of different viscosity with their corresponding dentin bonding systems. Thirty-six caries-free human maxillary incisors were prepared for facial ceramic veneers with cervical cavity margins located in dentin. Heat-pressed glass-ceramic veneers (IPS Empress) were inserted adhesively using one of the following luting systems: Sono-Cem (SC) with EBS; Variolink Ultra (VU), Variolink High Viscosity (VHV), and Variolink Low Viscosity (VLV) with Syntac. Both the cervical and the palatoincisal margins of the veneers (tooth/composite resin cement interface and ceramic/composite resin cement interface) were evaluated before and after thermocycling and mechanical loading (TCML) by quantitative margin analysis under a scanning electron microscope (SEM) using an image analysis system. Microleakage was assessed by dye penetration after TCML. Before TCML, SC and VU showed statistically significantly fewer marginal gaps than VHV and VLV. After TCML, SC, VU, and VHV revealed significantly fewer marginal gaps than VLV. TCML had a statistically significant influence on marginal gap formation at both the dentin and enamel margins. After TCML, the percentage of marginal gaps was not significantly different at the cervical dentin than at the palatoincisal enamel margins. Cervical dye penetration after TCML showed no statistically significant differences in microleakage among the four luting systems. In conclusion, this in vitro study showed that similarly favorable marginal adaptations of ceramic veneers to dentin and enamel can be achieved using Sono-Cem, Variolink Ultra, or Variolink High Viscosity with their corresponding dentin bonding systems.     

Pulpal response to a newly developed MMA based resin cement for bonding tooth-colored indirect restorations

PURPOSE: To evaluate the pulpal responses to a newly-developed MMA-based self-etch resin cement, when used as a luting agent for indirect resin composite restoration, and to compare the results with those obtained from a total-etch luting agent, glass-ionomer cement, and amalgam restoration. METHODS: 120 cervical cavities were prepared in monkey teeth and divided into four equal groups according to the restorative materials used: (1) the cavities were restored with resin composite inlays using a self-etch resin cement as a luting agent (M-Bond); (2) the cavities were also restored with resin composite inlays but using a total-etch resin cement as a luting agent (Super-Bond C & B); (3) the cavities were directly restored with glass-ionomer cement (Fuji II); or (4) the cavities were directly restored with amalgam (Dispersalloy). The restored teeth were extracted at 3, 30, or 90 days after restoration, then fixed in 10% neutral buffered formalin. The specimens were prepared using routine histopathological procedures. Five microm-thick sections were stained with hematoxylin and eosin or Brown & Brenn gram stain for bacterial observations. Histological responses in the pulpal tissue and bacterial penetration were observed under a light microscope and evaluated using standard scores. The results were statistically analyzed using the Kruskal-Wallis test (P< 0.05). RESULTS: At all time intervals, no significant differences of pulpal inflammatory responses between M-Bond and Super-Bond C&B were observed (P> 0.05). Both resin cements showed no serious pulpal responses, such as necrosis or abscess formation. In general, both MMA-based resin cements showed similar pulpal responses to those of glass-ionomer cement except for congestion of pulpal blood vessels at 3 days after restoration in which glass-ionomer cement exhibited a lower level than that of the MMA-based resin cements. For the group restored with amalgam, at 3 days after restoration, severe odontoblastic disorders and blood vessel congestions with a large infiltration of inflammatory cells were detected. At 30 and 90 days after restoration, slightly inflammatory irritations were observed irrespective of the materials used. Reparative dentin formation and bacterial penetration were found mostly in the group restored with amalgam.     

In vitro evaluation of wall-to-wall adaptation of a self-adhesive resin cement used for luting gold and ceramic inlays

PURPOSE: This in vitro study evaluated the wall-to-wall adaptation of a new self-adhesive resin-based cement (RelyX Unicem) in comparison with that of other cements when luting gold and porcelain inlays in standardized Class II cavities in extracted teeth. MATERIALS AND METHODS: In each experimental group (n = 10), a different combination of inlay and luting material was tested. Group 1: Porcelain Empress II (Ell) and RelyX Unicem (U); group 2: Ell and resin-based cement Variolink II in combination with primer and bonding Excite DSC; group 3: gold inlays (G) and U; group 4: G and Harvard zinc-oxy-phosphate cement; group 4: G and glass-ionomer cement Fuji Cem. After storage and thermocycling, microleakage testing was carried out and dye penetration was examined at the occlusal and cervical margins of each inlay. The differences in microleakage score were tested for statistical significance first comparing all groups, then pooling the groups for inlay material (Kruskal-Wallis nonparametric ANOVA and Mann-Whitney U test, p < 0.05). SEM observations of the tooth/cement/restoration interfaces were also made in each group. RESULTS: Harvard cement had the highest microleakage. The sealing ability exhibited by RelyX Unicem was satisfactory with both gold and porcelain inlays, and comparable to that of Fuji Cem and Variolink II. CONCLUSION: RelyX Unicem achieved an adequate seal on both enamel and dentin when used to lute in vitro gold and porcelain inlays.     

Comparison of microleakage of three acid-base luting cements versus one resin-bonded cement for Class V direct composite inlays

STATEMENT OF PROBLEM: Demineralized dentin beneath set cement may adversely affect microleakage under fixed restorations. PURPOSE: Microleakage of direct composite inlays cemented with acid-base cements and a methyl methacrylate resin cement were evaluated to determine their effect on the integrity of the underlying hybridized dentin. MATERIALS AND METHODS: Sixty Class V box preparations (3 mm x 3 mm x 1.5 mm) were precisely prepared in previously frozen bovine teeth with one margin in enamel and another margin in dentin. Direct composite inlays (EPIC-TMPT) for each preparation were divided into 4 groups of 15 specimens each and cemented with 3 acid-base cements (control group): Elite, Ketac-Cem, Hy-Bond Carbo-Cem, and 1 adhesive resin cement: C&B Metabond. All specimens were stored in distilled water for 24 hours at 37 degrees C before immersion in 0.5% basic fuchsin for 24 hours. The dye penetration was measured on the sectioned specimens at the tooth-cement interface of enamel and cementum margins and recorded with graded criteria under light microscopy (Olympus Vanox-T) at original magnification x 50, 100, and 200. A Kruskal-Wallis and the Mann-Whitney test at P<.05 were used to analyze leakage score. RESULTS: All cementum margins of the 3 acid-base cements tested demonstrated significantly higher leakage scores than cementum margins for inlays cemented with the resin cement tested(P<.01). No leakage along the tooth-cement interface was found for inlays retained with the adhesive resin cement. CONCLUSIONS: Within the limitations of this study, the 3 acid-base cements tested exhibited greater microleakage at the cementum margins than did the adhesive resin cement that was tested.     

Adhesion of Indirect MOD Resin Composite Inlays Luted With Self-adhesive and Self-etching Resin Cements

SUMMARY This study investigated the effect of loading on the bond strength to dentin and microleakage of MOD indirect composite restorations bonded with self-adhesive and self-etching resin cements with or without acid etching of the proximal enamel margins. Class II MOD cavities were prepared in 48 molar teeth into dentin and divided into three groups of 16 teeth. Impressions were taken and indirect composite inlays fabricated (Estenia C & B). The enamel margins of the proximal boxes of half the specimens were phosphoric acid etched, and the inlays were cemented with one of three cements (Panavia F 2.0, SA Cement, or Rely X Unicem). After luting, eight teeth in each cement group were mechanically loaded at 2.5 cycles/s for 250,000 cycles. Unloaded teeth acted as controls. Teeth were stored in Rhodamine B solution for 24 hours, sectioned buccolingually at the proximal boxes to examine microleakage using confocal microscopy, and further sectioned for μTBS testing of the resin-dentin interface. Analysis of variance was performed to assess the effect of loading and acid etching on microleakage and bond strength. Acid etching had no effect on microleakage. No significant difference in the dentin bond strengths between the three cements existed after loading. Panavia F 2.0 exhibited a significant reduction in bond strength. With regard to microleakage at the proximal boxes, loading had no effect on dye penetration at the cavity floor. However, at the axial walls, loading had a significant deleterious effect on Panavia F 2.0. No difference in microleakage existed between the three cements at both sites before and after loading. In conclusion, the two tested self-adhesive cements exhibited similar bond strengths before and after loading to the self-etching resin cement. Loading reduced dentin bond strengths and increased microleakage at the resin-dentin interface. However, acid etching of the enamel margins had no significant effect on microleakage in the approximal regions of the bonded inlays.     

两种树脂粘接剂粘接K2O-Al2O3-SiO2系统牙科玻璃陶瓷Ⅴ类洞嵌体的效果比较

目的评价2种树脂粘接剂与K2O-Al2O3-SiO2系统牙科玻璃陶瓷嵌体的粘接效果。方法24颗离体牙随机分为自固化组和双固化组,每组12颗,均预备Ⅴ类洞,分别使用自固化型树脂粘接剂和双重固化型树脂粘接剂粘接K2O-Al2O3-SiO2系统牙科玻璃陶瓷嵌体,热循环300次后浸入林格溶液待用。每组随机抽取6个样本,浸入品红溶液24 h后测量洞壁的染色渗透度。3个月后扫描电镜下观察余下6个样本粘接剂的丧失情况。结果自固化组粘接剂-牙体界面的染色渗透度小于双固化组（χ2=5.383,P=0.02）,粘接剂裂隙量小于双固化组（t=4.24,P〈0.001）。双固化组个别样本在陶瓷-粘接剂界面和粘接剂-牙体界面均出现粘接剂裂隙量较大的区域。结论自固化型树脂粘接剂粘接K2O-Al2O3-SiO2系统牙科玻璃陶瓷Ⅴ类洞嵌体的效果优于双重固化型树脂粘接剂。     

Correlation between microleakage and cement thickness in three Class II inlay ceramic systems

The objectives of this study include comparing the cement thickness and microleakage of Class II ceramic inlays built with three ceramic systems and verifying whether there was a correlation between those two variables. The ceramic systems used include: 1) Heat-pressed (IPS-Empress); 2) CAD-CAM (CEREC 2) and 3) Sintered (Colorlogic). Standardized MOD Class II inlay cavities with one proximal box extending below and the other extending above the cement-enamel junction (CEJ) were prepared in 30 extracted human molars and randomly assigned to three groups. The ceramic inlays were constructed according to manufacturer's instructions and cemented using a dual-cure resin cement (Variolink II). All teeth were mechanically cycled (100,000 cycles, 78N) and thermocycled (700 cycles, 5 degrees C-55 degrees C). After immersion in silver nitrate, the inlays were sectioned mesial-distally and evaluated with an optical microscope (40x). The cement thickness obtained by the Colorlogic system (enamel: 113 +/- 25 microm; dentin: 118 +/- 23 microm) was significantly higher than that obtained by CEREC (enamel: 78 +/- 14 microm; dentin: 87 +/- 13 microm) and Empress (enamel: 65 +/- 15 microm; dentin: 89 +/- 14 microm). Regarding dye penetration, there was no statistical difference among the three ceramic systems in enamel. At the dentin margins, the Colorlogic system resulted in a significantly higher penetration depth compared to CEREC and Empress, which had similar average values. No correlation was found between cement thickness and microleakage either in enamel or dentin for any of the ceramic systems.     

Effect of Resin Coating and Chlorhexidine on the Microleakage of Two Resin Cements after Storage

Purpose: This study evaluated the effect of resin coating and chlorhexidine (CH) on microleakage of two resin cements (Panavia F2.0, Nexus 2) after water storage. Materials and Methods: Class V cavities were prepared on the facial and lingual surfaces of 120 intact human molars with gingival margins placed 1 mm below the cementoenamel junction. Indirect composite inlays were fabricated. The specimens were randomly assigned into six groups (n = 40). Indirect composite inlays (Gradia) were cemented as follows: Group 1 (control): inlays were cemented with Panavia F2.0 according to the manufacturer's instructions. Group 2: the ED‐primed (ED Primer, Kuraray Dental, Tokyo, Japan) dentin was coated with a resin layer before cementation of the inlays with Panavia F2.0. Group 3: a 2% CH solution was applied before bonding with Panavia F2.0. Group 4: after CH application, the primed dentin was coated with a resin layer before cementation with Panavia F2.0. Group 5: (control) after applying Optibond Solo Plus, the inlays were cemented with Nexus 2. Group 6: after etching, CH was applied, and cementation was performed similarly to group 5. Half the specimens in each group were stored in distilled water for 24 hours, while the other half were stored in distilled water for 6 months. After storage, the teeth were placed in 1% methylene blue dye for 24 hours, sectioned, and evaluated under a 20× stereomicroscope. Dye penetration was scored using 0 to 3 criteria. Data were analyzed using nonparametric tests. Results : Resin coating of ED primer for Panavia F2.0 significantly reduced microleakage at the gingival margins after 6 months (p < 0.05). CH application in Panavia F2.0 did not lead to a significant difference in the microleakage at both margins, after 24 hours and 6 months (p > 0.05). The application of CH showed significantly less microleakage than that of the control group at the gingival margins of Nexus 2 after 6 months. In general, gingival margins showed more microleakage than occlusal margins. Conclusion: An additional resin layer applied to a self‐etch cement can improve long‐term dentinal sealing for indirect restorations, while CH cannot; however, CH reduces gingival microleakage in an etch‐and‐rinse cement after aging.     

In vitro push-out strength of seven luting agents to dentin

PURPOSE: New luting agents, described as resin-modified glass-ionomer cements and compomers, have been developed during the last decade to improve the retention of cemented restorations. The aims of this study were to (1) compare the push-out strength of these new luting materials against both conventional cements and bonding luting agents, and (2) evaluate the influence of dentin surface treatment on both glass-ionomer cement and 4-META adhesive resin push-out strength. MATERIALS AND METHODS: Conical standardized cavities were drilled in the center of coronal dentin disks. Ninety sandblasted Ni-Cr inlays, divided into nine batches, were luted into the cavities according to the surface treatment and the nature of the following luting agents: zinc phosphate cement, zinc polycarboxylate cement, type 1 glass-ionomer +/- polyacrylic acid, resin-modified glass-ionomer, polyacid-modified composite resin, filled bis-GMA phosphate ester resin, and 4-META adhesive resin +/- application of activated monomer. Each specimen was placed in a holding device, and a steel rod was used to apply a force on the inlay until rupture occurred. The push-out strength was calculated, and the failure mode was controlled. RESULTS: There were significant differences between some of the groups. The highest push-out strength was achieved by the 4-META adhesive resin after application of activated monomer. The lowest value was attained with zinc phosphate and polycarboxylate cements. CONCLUSION: Both resin-modified glass-ionomer and polyacid-modified composite resin luting materials exhibited a push-out strength similar to resin-based materials. Specific dentin surface treatments significantly enhanced the push-out strengths of glass-ionomer cement and 4-META adhesive resin.     

Effect of different luting procedures on the seating of ceramic inlays

This in vitro study evaluated the effect of different luting procedures on the proper seating of ceramic inlays and on the marginal seal through microleakage testing. Sixty mesial-, occlusal-, distal- (MOD) cavities were prepared in third molars, and distributed among four groups. In the control group 1, the cavity surface was treated with dentin and enamel bonding agents; ceramic inlays were placed into the cavity and light cured. In group 2, the dentin and enamel bonding agents were cured prior to the placing of the inlays, and following the insertion. In group 3, the inlays were luted without enamel bonding. In group 4, the inlays were cemented using a one-bottle bonding and two times light curing. The groups with only one time light curing at the end of the luting process exhibited the smallest luting space following cementation. The smallest dye penetration values were obtained for the two groups with separate light curing of the dentin bonding agent. Reducing the film thickness of polymerized dentin bonding agents, i.e. by changing the composition of the bonding agents, could facilitate proper seating of ceramic inlays together with a better marginal seal.     

Marginal leakage around V-shaped cavities restored with glass-ionomer cements: an in vitro study.

The object of this investigation was to assess the degree of marginal leakage around V-shaped cervical glass-ionomer cement restorations and compare it to that around composite resin restorations. Three different glass-ionomer cements and one composite resin control were assessed by means of dye penetration. Severe microleakage at the occlusal margins was found in 70% of the glass-ionomer cement restorations, but in only 10% of the composite resin restorations. A considerable amount of dye penetration was observed at the cervical margins of all restorations, including the controls. None of the glass-ionomer cements tested showed superiority in preventing marginal leakage occlusally or gingivally.     

钾铝硅系统牙科玻璃陶瓷嵌体边缘适合性的实验研究

目的：研究双固化粘结剂粘结钾铝硅（K2O-Al2O3-SiO2）系统牙科玻璃陶瓷的微渗漏情况。方法：制备钾铝硅系统牙科玻璃陶瓷瓷锭;选择清理24颗离体牙,即刻完成根管充填;在每颗离体牙的颊舌面颈部各预备一个V类洞型;将离体牙随机分成两组,第1组离体牙不预备粘结间隙、第2组离体牙预备约100μm的粘结间隙;用＂热压铸入＂法制作牙科陶瓷嵌体,用VariolinkⅡ双固化粘结剂粘结;从每组样本中随机抽取6颗离体牙,浸入25℃的品红溶液中24h,测量染色剂在洞壁的染色深度;另外12颗离体牙浸入25℃的复方生理盐水中2个月,在SEM下观察样本粘结剂的丧失情况。结果：染色渗透实验和SEM分析显示,两组样本均在陶瓷/粘结剂界面产生较高的边缘封闭质量（组1样本中陶瓷/粘结剂界面裂隙量的平均值为（12.4±4.5）%,明显低于组1样本中粘结剂/牙体界面裂隙量的平均值（38.9±8.8）%;组2样本中陶瓷/粘结剂界面裂隙量的平均值为（32.6±15.8）%,明显低于组2样本中粘结剂/牙体界面裂隙量平均值（67.9±23.1）%;没有粘结间隙的样本比有粘结间隙的样本具有更好的边缘适合性能（组1样本粘结剂裂隙量的平均值（15.7±7.3）%,明显低于组2样本中者（57.4±19.5）%。结论：较大的粘结间隙不能完全补偿双固化粘结系统树脂的聚合收缩,在使用双固化粘结系统粘结K2O-Al2O3-SiO2系统牙科玻璃陶瓷嵌体时应该避免制备较大的粘结间隙。     

Current luting cements: marginal gap formation of composite inlay and their mechanical properties.

OBJECTIVE: The aims of this investigation were to investigate the effect of thermocycling on the marginal gap formation of composite inlays using three types of luting cements (Compolute, PermaCem, Fuji Plus, Panavia 21: as a control) and on mechanical properties of four luting cements. METHODS: The maximum marginal gap in the dentin cavity of each of ten resin inlay specimens in each group, was measured by a microscope before and after 10,000 thermocycles. The dimensional change, shear bond strength to dentin, and material and conditions for flexural strength and modulus testing were examined. RESULTS: Compolute and Panavia 21 showed marginal gaps of approximately 10 microm before thermocycling. In contrast, the gap widths after thermocycling was significantly wider. Although the gap widths of PermaCem and Fuji Plus were approximately 60-110 microm prior to thermocycling, they were significantly smaller in width after thermocycling. Statistical differences in the shear bond strength to dentin were not observed before or after thermocycling for all materials. The flexural strength and modulus were significantly increased after thermocycling compared with three products and with all four products, respectively. SIGNIFICANCE: The mechanical properties of all four luting cements were closely related to their marginal gap formations and these mechanical factors have important roles in determining their marginal gap formations.     

冷热循环对自粘接树脂水门汀边缘适合性的影响

目的：对自粘接树脂水门汀（RelyX Unicem）与传统树脂水门汀系统（Panavia F,Variolink Ⅱ,Vtique）粘接嵌体边缘适合性进行对比研究。方法：48个新鲜拔除的第一磨牙分为4组,每组12个,分别选用d种树脂水门汀系统粘接嵌体,每组试件选取4个分别冷热循环0次,5000次,10000次后,放置于0．5％的品红溶液中染色24h,顺着嵌体长轴纵剖后在体视显微镜下观察微渗漏情况。结果：4种树脂水门汀系统在不同的冷热循环次数沿着粘接界面表现出低的微渗漏,4种树脂水门汀系统粘接嵌体无明显统计学差异义。结论：自粘接树脂水门汀具有与传统树脂水门汀相似的良好的边缘适合性。     

The marginal quality of luted ceramic inserts in bovine teeth and ceramic inlays in extracted molars after occlusal loading

PURPOSE: To compare the marginal adaptation of adhesively luted ceramic inserts in standardized cylindrical cavities of bovine dentin and enamel with the marginal adaptation of adhesively luted ceramic inlays in extracted molars after mechanical loading, and to calculate the minimum sample size required to differentiate between material groups based on the findings of this investigation. MATERIALS AND METHODS: Ceramic inserts of similar dimension were luted in standardized cylindrical cavities of bovine dentin and enamel (n = 6, O = 4 mm) with seven different adhesive/resin cement systems (Syntac/Variolink, Prime & Bond NT/Variolink, Excite DSC/Variolink, AdheSE/Variolink, Excite DSC/Multilink, Multilink Primer/ Multilink, RelyX Unicem). The same materials were used to lute ceramic inlays (Empress II) in three-surface cavities of extracted human molars (n = 6 per group). All specimens were submitted to 2000 cycles of thermocycling. In addition, restored teeth were submitted to cyclic loading (640,000 cycles, 50 N) in a chewing simulator. Replicas after stressing were analyzed with SEM, and the percentage of continuous margin of the inserts and the inlays was calculated, differentiating the proximal part of the inlay into cervical dentin/enamel and axio-proximal enamel. The mean percentage values per material group of the insert and inlay groups were ranked using relative ranks. Sample size estimation was done for pooled standard deviations comparing between two and seven materials and assuming 20% or 10% of the mean of continuous margin to be statistically significant. RESULTS: The Spearman correlation coefficient between the variables "insert dentin" and "inlay cervical dentin" was 0.71 (p = 0.07), between "insert enamel" and "inlay axio-proximal enamel" 0.07 (p = 0.9). The variability of the test results was large for both the insert and inlay variables, especially at the resin-dentin interface. No statistically significant difference between the materials could be found for the insert method when ANOVA and Bonferroni post-hoc tests were applied (p > 0.05), while the inlays luted with Prime & Bond NT/Variolink showed significantly less continuous margin at the cervical dentin than all other groups with the exception of RelyX Unicem. At least 16 (63) inlays and 14 (57) inserts had to be used per group for differences of 20% (10%) of the mean of continuous margin. CONCLUSION: To evaluate luting agents with regard to their ability to reduce marginal discrepancies, the inlay model is inadequate due to high sample numbers which make the test time-consuming and expensive; furthermore its clinical relevance is uncertain. Alternatively, the insert method may be a suitable screening method for dentinal margins, although its clinical relevance is also unknown.     

Marginal leakage in class II‐restorations after use of ceramic‐inserts luted with different materials

The efficiency of using prefabricated ceramic inlays to prevent microleakage has been discussed in different investigations. The purpose of this study was to evaluate the marginal microleakage of a new glass ceramic inlay system in combination with two different composite luting materials and one polyacid-modified composite, respectively. Standardized class II cavities (n = 60) were filled with (1) Empress^® inlays fixed with a highly viscous luting composite as a control group, and with glass ceramic inlays (Cerana^®) in combination with (2) a highly viscous luting composite, (3) a low-viscous luting composite and (4) a polyacid-modified composite, respectively. After thermocycling the marginal quality was analysed with scanning electron microscopy, and the dye penetration along the cavity walls was measured. The use of the Cerana^® inlays with a polyacid-modified composite resin did not reveal a good marginal adaption. However, the combination of the Cerana^® and the Empress^® inlays with the highly viscous composite exhibited a comparable marginal fit. Within the limitations of an in vitro study it is concluded that the combination of the new glass ceramic inlays with a polyacid-modified composite cannot be recommended for clinical use.     

Marginal adaptation of heat-pressed glass-ceramic veneers to Class 3 composite restorations in vitro

The aim of the present in vitro study was to compare the marginal adaptation and integrity of heat-pressed glass-ceramic veneers to adjacent class 3 composite restorations and to enamel using four dual-curing composite resin cements of different viscosity with their corresponding dentin bonding agents. Thirty-six caries-free human maxillary incisors were first restored with mesial and distal class 3 composite restorations and then prepared for facial ceramic veneers. The cavity margins of the veneers were located either in the class 3 composite restorations or in the residual enamel. Heat-pressed glass-ceramic veneers (IPS Empress) were inserted adhesively using one of the following four luting systems in nine teeth: SonoCem (SC) with EBS; Variolink Ultra (VU), Variolink High-Viscosity (VHV), and Variolink Low-Viscosity (VLV) with Syntac. The veneer margins in the region of the composite restoration and in the region apical to the composite restoration (ceramic/composite resin cement interfaces, composite resin cement/composite restoration interface, and composite resin cement/enamel interface) were evaluated before and after thermo-cycling and mechanical loading (TCML) by quantitative margin analysis under a scanning electron microscope (SEM) using an image analysis system. Furthermore, microleakage was assessed in each tooth by dye penetration after TCML. For all luting systems, SEM analysis revealed excellent marginal adaptation of the ceramic veneers to the composite restorations as well as to enamel. The median percentages of marginal gap formation were 1.1% and less before TCML and 5.1% and less after TCML. The error-rates method revealed no statistical influence of the interface or of the viscosity of the luting material. Maximal values of dye penetration showed a significantly higher microleakage at veneers cemented with VU (median: 86.4%) compared to SC (median: 13.3%). In conclusion, the present data demonstrated that existing clinically acceptable class 3 composite restorations have no negative influence on the marginal adaptation of ceramic veneers. This was valid independent of the viscosity of the dual-curing composite resin cement when SC, VHV, or VLV was used.     

Analysis of marginal adaptation and sealing to enamel and dentin of four self-adhesive resin cements

This in vitro study compared the marginal adaptation of all-ceramic MOD-inlays luted to human molars with four self-adhesive resin cements. Thirty-two human third molars were randomly assigned to four test groups (n = 8 per group). MOD cavities were prepared with approximal finishing lines in dentin and enamel. All-ceramic Empress 2 inlays were luted with four self-adhesive cements (Clearfil SA, iCEM, Bifix SE, seT). Oral stress was simulated by 90 day storage in water as well as by thermal and mechanical loading (TCML, 1.2 × 10⁶ × 50 N, 6,000× 5°/55°, 1.6 Hz). The marginal fit was evaluated by scanning electron microscopy (SEM) and dye penetration. Data were analyzed with the ANOVA/Tukey's test (α = 0.05). The SEM investigation of the gingival cement margins (cement–tooth interface) showed values of perfect margin [percent] (means ± SD) after simulated aging between 84 ± 9% and 95 ± 5% for enamel and 80 ± 9% and 92 ± 3% for dentin. In enamel, seT showed significantly higher marginal integrity than iCEM after water storage and TCML (post hoc; p = 0.011). Furthermore, the marginal adaptation of iCEM in enamel deteriorated by simulated aging (p = 0.014, ANOVA). Mean values of dye penetration (percentage of dye entry into dentin) at the investigated restorations margins ranged between 3% and 8% for enamel and 12% and 22% for dentin. Clearfil SA, iCEM, and seT showed lower dye penetration in enamel than in dentin (Clearfil SA: p = 0.013, iCEM: p = 0.044, seT: p = 0.003). The results suggest that the four self-adhesive luting agents investigated seem to successfully bond to dentin-restricted as well as to enamel-restricted cavities, predicting good clinical performance.     

Effects of cement-curing modes on dentin bonding of inlays.

The aim of this in vitro study was to evaluate dentin adhesion after cementation of immediate direct "All Purpose" Hybrid (AP.H) composite inlays (Dentsply) and Cerec Dicor-MGC (Dentsply) inlays with the dentin adhesive Prisma Universal Bond 2 (Dentsply) and the dual-curing Dicor-MGC luting composite (Dentsply). In 24 extracted human molars, standard MOD cavities were prepared with one approximal margin located in enamel and the other one located in dentin. They were divided into four groups: (I) AP.H inlays, luting composite only, chemically cured; (II) AP.H inlays, luting composite, immediately-light-cured; (III) AP.H inlays, luting composite, initially chemically and delayed-light-cured (15 min); and (IV) MGC inlays, luting composite, initially chemically and delayed-light-cured (15 min). In vitro load cycles corresponding to five years of clinical stress followed. Initially and after specimens were loaded, the margins were analyzed quantitatively by SEM. The tooth/cement and cement/inlay interfaces were scored separately. The initial percentages of "continuous margin"--at both the tooth/luting composite and luting composite/inlay interfaces--were higher than 94% for all groups. At the end of the load cycles, the quality of the margins at the tooth/luting composite interface significantly decreased for all groups. The highest decrease was found for the cervical margins located in dentin, where only 37%-61% were scored as "continuous margin". The AP.H inlay/luting composite interface showed almost no change. At the MGC inlay/luting composite interface, the percentage of "continuous margin" decreased to 74%. After specimens were loaded, the percentage of "continuous margin" in dentin was lower than in enamel, despite the use of a dentin bonding agent (PUB 2).(ABSTRACT TRUNCATED AT 250 WORDS)