Clinical and semiquantitative marginal analysis of four tooth-coloured inlay systems at 3 years

Objectives: The marginal quality of four tooth-coloured inlay systems was clinically investigated and subjected to computer-aided semiquantitative marginal analysis under scanning electron microscopy (SEM) after 3 years of clinical service.

Methods: Three of the restoration types were made using the Cerec CAD-CAM apparatus: one was milled from preformed glass ceramic blocks, and the two other inlay types were milled from preformed porcelain blocks. The fourth system was based on an experimental indirect resin composite inlay system. Each inlay type was luted with a different luting resin composite. The clinical evaluation was performed with a mirror and explorer by two clinicians separately, and the marginal analysis was conducted microscopically on replicas (SEM × 200).

Results: After 3 years in situ, all the restorations were clinically acceptable. No recurrent caries was observed. Marginal analysis under SEM detected a high percentage of submargination for all four systems, which suggests that their respective resin composite luting agents were all subject to wear. The percentage of marginal fractures on the enamel side as well as on the inlay side did not increase dramatically compared to the 6-month results.

Conclusion: The first recall after 6 months of clinical service indicated how tooth-coloured inlays behave at their margins. The 3-year results confirmed the early findings, indicating that wear of resin composite lutes is important and present in all systems. The two ceramic materials showed a similar behaviour at the margins. The resin composite inlay performed better at the inlay site than at the enamel site.     

Radiographic detection of overhangs formed by resin composite luting agents

Objectives: An in vitro model was used to assess the ability of standard radiographic techniques to detect marginal overhangs of resin composite luting agents beside porcelain and resin composite inlays.

Methods: The radiodensity of five commercially available luting resins was determined using ISO 4049 methodology. For four of the luting agents, artificial overhangs (0.5 × 0.5 × 2 mm) were created at the cervical margin of standard resin composite and porcelain inlays. Radiographs were recorded, using wax as a tissue equivalent, and the overhangs reduced incrementally in depth by 0.5 mm with serial images at each depth. The images were assessed in random sequence by three observers.

Results: There were significant differences between the radiopacity of the luting resins. These correlated well with the ability of the observers to detect marginal overhangs adjacent to resin composite inlays.

Conclusions: Even with the most radiopaque luting material, a substantial marginal ledge could not be detected in association with a radiopaque resin composite inlay. The threshold for detection of the overhang was lower when using a radiolucent porcelain inlay.     

Influence of resin cement viscosity on microleakage of ceramic inlays.

OBJECTIVES: The aim of the present investigation was to evaluate the effect of the different viscosities of two resin luting cements on microleakage of ceramic inlays at dentinal margins. The effect of the width of the space between inlay and tooth, on the quality of the marginal seal was also investigated. METHODS: Mesial and distal class V cavities were prepared in 48 extracted third molars. The incisal margins of the cavities were in enamel and the cervical margins in dentin. Subsequently, Empress inlays with different cervical margin gap dimensions were fabricated. The mean cervical gap dimensions in the respective groups were as follows: group 1 (27 microm); group 2 (232 microm); group 3 (406 microm). Half the inlays in each group (16) were cemented with a low viscous resin luting cement, and half (16) with a highly viscous resin luting cement. The teeth were subjected to occlusal loading with synchronized thermal cycling in a masticatory simulator. Then, the specimens were immersed in basic fuchsin solution, and dye penetration along the cavity walls was measured. In addition, marginal adaptation was analyzed in the SEM at baseline and after loading, using a replica technique. RESULTS: With regard to dye penetration at dentinal margins, the highly viscous cement performed statistically significantly better at dentin/composite margins than the low viscous cement (p=0.0158). These findings are supported by SEM analysis. SIGNIFICANCE: It is assumed that polymerization stress within the luting cement could not be completely compensated for by larger luting spaces. Highly viscous luting cements are recommended for cementing class V inlays in larger luting spaces.     

Marginal adaptation of a sintered ceramic inlay system before and after cementation

summary The long term clinical performance of porcelain inlays depends on a number of factors and the marginal adaptation is one of significant interest. The purpose of this in vitro study was to evaluate the marginal integrity of a sintered inlay technique (Ducera®), before and after cementation. MOD cavities without bevels were prepared on 10 human mandibular molar teeth and porcelain inlays were fabricated according to the manufacturer's instructions. Inlays were evaluated microscopically for their adaptation to the occlusal and approximal margins of the tooth by means of a replica technique. Inlays were cemented with a dual-cured bybrid composite luting material (Enforce®). After polishing, each tooth was sectioned in buccal/lingual and mesial/distal directions following the same procedure in the sectioning of replicas. The marginal gap and the thickness of exposed cement were measured at each section. The mean marginal gap of 71.83 ± 8.93 μm recorded for the occlusal margin before cementation was significantly smaller than that of 1056 ± 39.33 μm calculated at the approximal margin. Following the cementation, the adaptation of the inlays at the occlusal margin was also found to be superior to that of the approximal margin. Comparison of mean gap values before and after cementation revealed that the marginal gap increased by 6.94 μm and 23.25 μm at the occlusal and approximal margins, respectively. Although polishing was performed after cementation, excess luting material was still observed, that caused an increase in the width of the exposed luting cement.     

Marginal quality of tooth-colored restorations in class II cavities after artificial aging

This in vitro study compared the proximal marginal adaptation of direct composite restorations with composite and ceramic inlays inserted with different resin cements. Standardized MOD Class II inlay cavities with one proximal box extending below and the other above the CEJ were cut in 48 extracted human molars and randomly assigned to six groups (n=8). Incrementally layered direct composite restorations (P60), composite inlays (P60) and ceramic inlays (Empress; Cerec Vitablocs Mark II) were placed in the cavities. Three different resin cements (RelyX ARC; Variolink II high viscosity; Panavia 21) were used for luting the composite inlays. All ceramic inlays were cemented with RelyX ARC. After finishing and polishing, the teeth were stored for 24 hours in Ringer solution at 37 degrees C before they were subjected to thermal and mechanical loading (5/55 degrees C, 2000x; 50 N vertical load, 50000x). Margins were evaluated on epoxy replicas using a scanning electron microscope at X200 magnification. Statistical analysis was performed with non-parametric test methods (alpha=0.05). The adhesive interfaces to enamel exhibited high percentages of perfect margins for all groups (91.8% to 96%) and a maximum of 5.2% marginal gap formation. Dentin-limited cavity segments demonstrated more marginal openings and less perfect margins than enamel-bound areas; however, this was only statistically significant for direct composite restorations and composite inlays inserted with Variolink II and Panavia 21. RelyXARC showed a significantly better adaptation to P60 inlays compared with the leucite-reinforced Empress ceramic but not the Vitablocs Mark II ceramic.     

Three-dimensional finite element analysis of strength and adhesion of composite resin versus ceramic inlays in molars

STATEMENT OF PROBLEM: Previous studies on strength of teeth reconstructed with ceramic or composite resin inlays have not resolved which restoration material provides the highest strength and marginal integrity. PURPOSE: The purpose of this study was to compare strength of mandibular molars restored with composite resin inlays to those restored with ceramic inlays, according to the Mohr-Coulomb failure criterion, and to analyze contact stresses in cement-tooth adhesive interfaces of these inlays. MATERIAL AND METHODS: The investigation used a 3-dimensional (3-D) finite element analysis with the use of contact elements. Seven 3-D models of first molars of the same shape and size were created: IT, intact tooth; UT, unrestored tooth with an MOD cavity preparation; CRIT, tooth restored with composite resin inlays (True Vitality) with an elastic modulus equal to 5.4 GPa; CRIH, tooth restored with composite resin inlays (Herculite XRV) (9.5 GPa); CRIC, tooth restored with composite resin inlays (Charisma) (14.5 GPa); CRIZ, tooth restored with composite resin inlays (Z100) (21 GPa); and CI, tooth restored with a ceramic (IPS Empress) inlay with an elastic modulus equal to 65 GPa. Each model was subjected to a force of 200 N directed to the occlusal surface. The stresses occurring in the tested inlays, composite resin cement layer, and tooth tissues were calculated. To evaluate the strength of materials, the Mohr-Coulomb failure criterion was used. Contact stresses in the cement-tissue adhesive interface were calculated and compared to tensile and shear bond strength of the luting cement to enamel and dentin. RESULTS: In the teeth restored with composite resin and ceramic inlays, the values of the Mohr-Coulomb failure criterion were lower than in the unrestored tooth with a preparation (UT), but still 2.5 times higher than in the intact tooth (IT). For the ceramic inlay (CI), the values of the Mohr-Coulomb failure criterion were nearly 3 times higher than in the composite resin inlays. For the luting agent for the ceramic inlay model, these values were 2-4 times lower than for the luting agents for the composite resin inlay models. At the adhesive interface between the cement and tooth around the ceramic inlays, contact tensile and shear stresses were lower than around the composite resin inlays. In the cervical enamel surrounding the proximal surface of the inlays, the stresses exceeded the tissue strength. CONCLUSIONS: Adhesively bonded composite resin and ceramic inlays reinforce the structure of prepared teeth, but do not restore their original strength. The proximal enamel surrounding inlays is prone to failure. The value of the Mohr-Coulomb failure criterion for ceramic inlays was higher than for composite resin inlays. With an increase in the elastic modulus of inlay materials, the values of the Mohr-Coulomb failure criterion decrease in the luting cement. Contact tensile and shear stresses on the cement-tissue adhesive interface decrease as well.     

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)     

Effect of different luting materials on the marginal adaptation of Class I ceramic inlay restorations in vitro.

OBJECTIVES: The aim of this in vitro study was to assess the marginal adaptation of prefabricated Class I ceramic inlay restorations placed with various luting materials. METHODS: Forty-two standardized occlusal cavities were prepared in extracted human molars with diamond burs exactly corresponding to the dimensions of prefabricated glass ceramic inlays. The prepared teeth were randomly assigned to seven groups of six teeth each and restored using (1). the composite resin Tetric Ceram in increment technique [Group I] or (2). ceramic inlays (Cerana) luted with: the composite based materials Dual Cement [Gr. II] and Panavia 21 [Gr. III], the compomer material Dyract Cem [Gr. IV], Dyract Cem with additional use of Prime & Bond 2.1 [Gr. V], the silicophosphate cement Trans-Lit [Gr. VI], or the ethylcyanoacrylate Cyano-Veneer [Gr. VII]. Marginal adaptation was evaluated by SEM-analyses before and after thermal cycling (2500 cycles; 5-55 degrees C) and mechanical loading (100N; 500000 cycles) using replica models. Kruskal-Wallis H-test and Mann-Whitney U-test were used for statistical analyses. RESULTS: Group I (increment technique) as well as Groups II-V (inlay technique) revealed high percentages of perfect marginal adaptation in over 95% of the analyzed margins, both before and after thermo-mechanical loading. Statistical significant differences could not be detected within these groups. All inlays luted with silicophosphate cement (Group VI) and four of six inlays applied with Cyano-Veneer (Group VII) fractured under occlusal load. SIGNIFICANCE: A stable bonding to the enamel and to the ceramic inlay was achievable with the composite luting resins Dual Cement and Panavia 21 as well as with the compomer based luting material Dyract Cem but not with the use of the silicophosphate cement Trans-Lit or the ethylcyanoacrylate Cyano-Veneer.     

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.     

In vivo and in vitro evaluation of marginal fit of class II ceromer inlays

The aim of this study was to evaluate the marginal adaptation of class II ceromer (Targis, Vivadent) indirect inlay restorations under both in vivo and in vitro conditions. Twenty Targis inlays were produced for class II inlay cavities (13 mandibular and seven maxillary teeth) in 20 patients. The in vivo adaptation of the inlay to the tooth cavity was evaluated by means of silicone replica technique. For in vitro evaluation, 20 mesio-occluso-distal (MOD) Targis inlays were made in extracted upper molars. Half of the inlays were cemented with Variolink high-viscosity resin cement while the other half was cemented with Variolink Ultra. The replica specimens and in vitro samples were sectioned buccolingually and mesiodistally, and marginal adaptation was evaluated at both proximal and occlusal margins at 200x magnification under a light microscope. The data was analyzed with anova (P < 0.05). The in vivo mean film thickness values for occlusal and proximal locations were recorded as 73 and 132 microm respectively. In vitro mean marginal fit values were observed as 48 and 67 microm for occlusal and proximal margins of inlays luted with Variolink II high viscosity. The marginal fit values recorded under in vivo conditions were higher in magnitude than the measurements obtained under in vitro conditions. The use of a highly filled resin luting agent with an ultrasonic insertion technique did not cause an increase in marginal gap width of the inlay.     

Interfacial gaps following ceramic inlay cementation vs direct composites

This study compared the interfacial integrity of Class II ceramic inlay restorations and direct resin composite restorations. The influence of a flowable resin composite liner was also evaluated. Class II DO cavities were prepared in 40 recently extracted mandibular molars and assigned to four treatment groups. Group A: direct composite restoration; Group B: Cerec inlays fabricated and cemented with a resin cement; Group C: adhesive lining with a flowable resin composite used prior to resin composite restoration; Group D: lining with a flowable resin composite prior to cementation of Cerec inlays. After finishing, polishing and thermocycling (4 degrees C and 60 degrees C x 500), the samples were cross-sectioned in a mesio-distal direction along the center of the fillings or inlays. The cross-sectioned surface was polished, and the adhesive interfaces between resin and enamel or dentin were observed under a scanning laser measurement microscope. Ceramic inlay restorations showed no interfacial gaps in enamel, but direct resin composite restorations showed a significantly higher incidence of gaps at the interface or cracks in the interfacial enamel (p=0.0002). No differences were found in the resin-dentin interfaces for both the inlay and direct resin composite restorations. The use of a flowable resin composite as an adhesive liner produced a significantly greater gap-free resin-dentin interface in Cerec inlay and direct resin composite restorations (p=0.0233 & 0.0009), but it did not reduce gap formation at the resin-enamel interface.     

Marginal adaptation with glass-ceramic inlays adhesively luted with glycerine gel

The purpose of this study was to examine the effectiveness of glycerine gels in preventing the formation of an oxygen-inhibition layer during the polymerization of composite resin materials. Sixteen glass-ceramic inlays were adhesively luted with and without the application of glycerine gels on the inlay margins before the polymerization of the luting composite resin material. To remove the oxygen-inhibition layer, the inlays were brushed with acetone. Replicas were obtained before and after acetone brushing, and a computerized quantitative marginal analysis was carried out under the scanning electron microscope. Statistical analysis revealed significant differences between the polymerization with and the polymerization without the use of a glycerine gel. The inlay margins polymerized after the application of a glycerine gel showed better marginal adaptation than did the inlay margins polymerized without it, suggesting that oxygen inhibition during polymerization can be prevented by the application of glycerine gels to the surface of composite resin materials.     

Clinical and quantitative marginal analysis of feldspathic ceramic inlays at 4 years

The aim of this clinical study was to evaluate feldspathic ceramic inlays both by clinical criteria and quantitative margin analysis in continuation of an earlier, identically conducted 2-year study. Fifty feldspathic ceramic inlays were adhesively luted in Class II preparations with all margins located in enamel. The inlays were evaluated clinically according to modified USPHS criteria after 3 and 4 years. Quantitative margin analysis was performed with a scanning electron microscope (SEM). Clinically, the inlays showed no recurrent caries and no changes in colour, but superficial marginal discolouration (6%) was apparent after 4 years. Margins were perceptible clinically in 64% of the cases after 4 years. Quantitative margin analysis showed significantly more marginal gaps at the composite/ceramic interface than at the enamel/composite interface. There was neither a significant decrease in perfect margins nor a significant increase in marginal gaps and marginal imperfections at both interfaces between the third and fourth year. Clinically, the inlays performed very well up to 4 years. Clinical evaluation using an explorer only detected substance loss in the cementation gap. The SEM evaluation showed significantly higher changes in marginal qualities during the first 2-year interval of clinical service compared to the second 2-year interval following an exponential mathematical regularity. Quantitative margin analysis should be included in clinical long-term trials to detect early marginal deficiencies at the luting interfaces. Received: 1 September 1997 / Accepted: 31 October 1997     

Marginal adaptation of four tooth-coloured inlay systems in vivo.

This study investigates the margin quality of four different tooth-coloured inlay systems using computer-aided quantitative margin analysis under scanning electron microscopy. Three types of restorations involved chairside procedures using a commercial CAD-CAM apparatus: one type of inlay restoration was milled from preformed glass ceramic blocks, the other two inlay types were milled from preformed porcelain blocks. The fourth system was based on an experimental indirect composite inlay system. Each inlay type was luted with its respective dual-curing luting composite, which was supplied with the system. After 6 months of clinical service, all four systems revealed a significant percentage of submargination indicating occlusal wear of the luting composite. The porcelain inlays and the composite inlays luted with their respective experimental luting composite showed the best marginal adaptation. Luted glass ceramic inlays, in particular, suffered from a significantly higher percentage of inlay margin fractures (9 per cent) and marginal openings (4 per cent) than the other systems. A possible explanation is that the glass ceramic subsurface structure at the inlay-lute interface was weakened by etching with ammonium bifluoride.     

Microleakage of direct and indirect inlay/onlay systems

summary The purpose of this in vitro study was to evalu ate the microleakage of direct and indirect inlay/onlay systems. Two of the groups investigated have indirect applications only and consist of microfine composites. The other two groups of inlay/onlay systems have both direct and indirect applications and are hybrid compos ites. Standardized MOD preparations were cut in 60 extracted human premolars. One gingival margin was placed in enamel above the cementoenamel junction (CEJ) and the other was placed in dentine below the CEJ. The inlays were made and luted according to each manufacturer's recommendation. The restored teeth were thermocycled and immersed in a basic fuchsin solution for 24 h. Following the mesiodistal sectioning of the specimens, extent of dye penetration at the restoration-glass ionomer cement and tooth-glass ionomer cement interfaces were scored using a stereomicroscope. Both direct and indirect inlays showed substantial leakage at gingival-dentine mar gins. However, there was only superficial leakage at enamel margins. Comparing the overall indirect inlay systems, EOS inlay leaked the most ( P ≤0.05). Indirect Brilliant Dentin^® inlays showed a significantly smaller amount of leakage than the other inlay systems. SR- Isosit^® and Estilux Posterior C VS^® inlays provided a favourable marginal seal. In the case of Brilliant Dentin^® and Estilux Posterior C VS^®, indirect inlays leaked more than direct inlays. Generally, no significant difference was observed between the interfaces evaluated in microleakage performance.     

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。     

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.     

Direct resin composite inlays/onlays: an 11 year follow-up

OBJECTIVES: The aim of this study was to present an 11-year assessment of direct resin composite inlays/onlays. METHODS: One-hundred Class II direct resin composite inlays and 34 direct resin composite restorations were placed in 40 patients. The restorations were evaluated clinically, according to modified USPHS criteria, annually over a 11-year period. RESULTS: Of the 96 inlays/onlays and 33 direct restorations evaluated at 11 years, 17. 7% in the inlay/onlay group and 27.3% in the direct restorations group were assessed as unacceptable. The differences in longevity were not statistically significant. The main reasons for failure for the inlays/onlays and direct restorations were fracture (8.3 and 12. 1%, respectively), occlusal wear in contact areas (4.2 and 6.1%, respectively) and secondary caries (4.2 and 9.1%, respectively). Eight of the non-acceptable inlays/onlays and five of the direct restorations were replaced, while the other ones were repaired with resin composite. Unacceptable wear was observed in occlusal contact areas of six restorations, in patients who were severe bruxers. For the other restorations occlusal wear was not found to be a clinical problem and no difference was observed between the inlays/onlays and direct composite restorations. The marginal adaptation of the inlays/onlays was still good at the end of the study. Ditching was only observed in a few inlays. A higher failure rate was observed in molar teeth than in premolar teeth. CONCLUSIONS: Good durability was observed for the direct resin composite inlay/onlay technique. Excellent marginal adaptation and low frequency of secondary caries in patients with high caries risk were shown. No apparent improvement of mechanical properties was obtained by the secondary heat treatment of the inlays. Also, the difference in failure rate between the resin composite direct technique and the inlay technique was not large, indicating that the more time-consuming and expensive inlay technique may not be justified. The direct inlay/onlay technique is recommended to be used in Class II cavities of high caries risk patients with cervical marginal placed in dentin.     

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.     

Marginal seal comparisons between resin-bonded Class II porcelain inlays, posterior composite restorations, and direct composite resin inlays

The microleakage of indirect porcelain and direct composite resin-bonded inlays was compared with that of posterior composite resin restorations using Class II preparations of extracted molar teeth. The resin-bonded inlay restorations provided a better marginal seal at the cervical restoration/dentin interface than did the composite resin restoration. The efficacy of this marginal seal varied with the particular treatments and materials used. Resin-bonded porcelain inlays had a higher incidence of cervical excess from the composite resin luting agent than did the posterior composite resin restorations.