A comparison of the marginal and internal adaptation of amalgam and resin composite restorations in small to moderate-sized Class II preparations of conventional design.

OBJECTIVE: The purpose of this study was to compare the marginal and internal adaptation of a non-gamma-2 amalgam and an ultrafine compact-filled light-cured composite in small to moderate-sized Class II restorations of conventional design. METHOD AND MATERIALS: Fifty recently extracted human premolar and permanent molar teeth were selected for the study. The teeth were restored with either a non-gamma-2 amalgam alloy or a light-cured resin composite. The marginal adaptation of the restorative materials to the proximal surface outline form of each preparation was assessed. The mean percentages of perfect margins, marginal fissuring, and underfilled margins for the 2 restorative materials were recorded and statistically analyzed. RESULTS: Both materials performed equally well in the buccal and lingual segments of the proximal box. At the cervical margin, the resin composite restorations showed a significantly greater number of imperfect margins and marginal fissuring. The incidence of underfilled margins was low for both restorative materials even at the cervical margin. CONCLUSION: Although there was some cause for concern about the marginal adaptation of the resin composite restorations along the cervical margin, the findings support contemporary teaching that small to moderately sized conventional Class II preparations may justifiably be restored with an appropriate resin composite.     

Marginal fracture of posterior composite resins

This study assesses the early cavomarginal breakdown of the newer posterior composite resin restorations compared with that of amalgam restorations. A total of 432 posterior composite restorations and 73 amalgam restorations were examined: 121 composite restorations (28%) and 44 amalgam restorations (60%) clinically showed a marginal crevice at some point on the cavosurface margin of the restoration at 6-month, 1-year, and 2-year recalls. The largest single reason for poor marginal adaptation was marginal fracture. Up to 2 years, the marginal integrity of the studied posterior composites was superior to that of an amalgam alloy. It was determined that smaller cavities, greater bulk of resin at the margin (especially at functional cusp areas), and well-finished margins without overfiling seem to reduce the occurrence of marginal fracture on composite resin restorations.     

Fracture strength of Class I versus Class II restored premolars tested at the marginal ridge. I. Standard preparations

Two groups of maxillary premolars with Class I cavities were prepared with one marginal ridge thickness to a width of 1.0 mm. One group was restored with amalgam and the other group with composite resin. Two groups of Class II cavities also were prepared and restored with amalgam and composite resin. The teeth in the four treatment groups were subjected to a centric load at the marginal ridge until fracture occurred. A two-factor analysis of variance revealed a statistically significant difference between the class of preparation (Class I preparations were weaker than were Class II preparations) but differences in strength between restorative materials (composite resin versus amalgam) and the interaction effect (class of preparation x restorative materials) were not found to be statistically significant (alpha = .05). A Newman-Keuls sequential range test found no statistically significant differences in strength between groups (alpha = .05). Fracture patterns were observed under scanning electron microscope. Fractures extended into the enamel and into the material in the Class I composite resin, Class I amalgam, and Class II composite resin restorations. Fractures extended only into the material in Class II amalgam restorations.     

Adaptation and condensation of amalgam restorations in Class II preparations of conventional and conservative design.

The purpose of this study was to investigate in vitro the adaptation and condensation of the proximal section of amalgam restorations placed in Class II preparations of conventional and conservative designs. The amalgam restorations were placed with traditional hand instruments with and without the aid of an automatic amalgam condenser. The restorations and sections of the restored teeth were examined and scored for adaptation and porosity. The restorations in the preparations of conservative design, especially those placed without the aid of the automatic condenser, exhibited more adaptation defects, porosity, and voids than did the restorations in the preparations of conventional design. It is necessary to identify and describe instruments and techniques that will facilitate the placement of amalgam restorations in preparations with limited access.     

Observations on a composite resin for Class II restorations: Three-year report

The results of these three-year observations comparing a composite resin with amalgam in Class II restorations do not differ greatly from those reported after two years. Secondary caries has not been a problem to date, regardless of the material used. Anatomic form of the amalgam restorations continued to be maintained while it deteriorated further in the composite resin restorations. On the other hand the composite restorations maintained the same level of superiority for marginal adaptation throughout the three years. No significant increase in the discoloration of the composite restorations or their margins were observed at three years, although most restorations had already shown evidence of discoloration at the previous evaluations.     

Effect of pre- and postoperative bleaching on marginal leakage of amalgam and composite restorations.

OBJECTIVES: The aim of this study was to investigate the effect of pre- and postoperative bleaching with 10% carbamide peroxide on marginal leakage of amalgam and resin composite restorations. METHOD AND MATERIALS: Three groups were made using 30 extracted, caries-free third molars (n = 10). In the preoperative group, bleaching was performed with 10% carbamide peroxide, followed by the placement of resin composite and amalgam restorations on Class V cavity preparations. In the postoperative group, bleaching was performed after the resin composite and amalgam restorations were fabricated. The third group served as a control in which no bleaching was performed. Dye penetration was used for evaluation of marginal leakage. RESULTS: Chi-square test showed that marginal leakage of resin composite restorations increased in both pre- and postoperatively bleached groups, but marginal leakage of amalgam restorations showed no alterations. CONCLUSION: Bleaching with carbamide peroxide may alter the marginal leakage of resin composite restorations, but amalgam restorations are not affected adversely in vitro.     

Critical appraisal. Class II composite resin restorations with gingival margins in dentin

The rising demand for esthetic restorations has considerably increased the number of direct composite restorations being placed in private practices. While composite resin is often selected primarily for its esthetic qualities, another significant advantage of direct composite restorations is the ability to perform conservative cavity preparations. The traditional configuration used for amalgam restorations is no longer mandatory; thus, more sound tooth structure can be preserved.
The technique of composite placement is complex when compared to amalgam placement. The use of adhesive systems prior to placement of composite restorations requires not only excellent isolation to avoid contamination, but also precise manipulation of the adhesive system. While stable bonds to enamel are routinely obtained, the heterogeneous composition and intricate morphology of dentin makes this substrate more challenging to restore. In addition, the cavity configuration (C-factor) and inherent polymerization shrinkage of composite resin play an important role in the durability of the composite–dentin interface. Class II preparations often have gingival margins in root surfaces because of the location of the caries lesion. Clinicians are then faced with a preparation that is challenging to isolate, has a relatively high C-factor, and relies on optimal bonding to dentin to secure long-lasting marginal integrity. Various restorative techniques, such as incremental placement or the use of an intermediate layer (flowable composite or resin-modified glass ionomer cements—open sandwich technique), have been some of the methods proposed to increase the longevity of composite restorations, especially those with margins in dentin. This review evaluates some of the published research on Class II composite resin restorations with margins in the dentin/cementum.     

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.     

Direct placement restorative materials for use in posterior teeth: the current options

The purpose of this paper is to provide guidelines to assist in the selection of dental materials for restoring posterior teeth in adolescents. Currently, amalgam is still the best plastic restorative material for some Class I cavities, and for Class II cavities and all multi-surface restorations. Tooth-coloured materials are preferred by some patients and dentists, however these alternatives are more technique sensitive than amalgam. Composite resin is the most common direct placement alternative to dental amalgam, providing patients with relatively low cost, tooth-coloured restorations. However, composite resins have limited indication, their placement is more time-consuming than for amalgam, cost-benefit considerations are a concern, difficulty in obtaining a marginal seal persists and there are few long-term studies published in the peer reviewed scientific literature. The literature currently supports the use of composite resin for the restoration of a limited range of Class I and Class II cavities. Composite resin restorations are not recommended for MOD or other multi-surface restorations. In selected clinical situations, fissure sealants, preventive resin restorations and glass ionomer cement are also appropriate materials to use to restore posterior teeth. Fissure sealants, when properly maintained, can play a significant role in the prevention and control of dental caries in pits and fissures in primary and permanent teeth. Preventive resin restorations should be placed to restore deep pits and fissures with incipient caries and/or developmental defects in primary and permanent teeth. Glass ionomer cement may be used for restoring Class V cavities where appearance is not the primary concern, for conservative Class III cavities, and as a provisional restorative material. It is not recommended for Class II or IV restorations.     

Margin quality and microleakage of Class II composite resin restorations

Margin quality and isotope microleakage analyses of Class II restorations placed in extracted human molars were compared using various composite resins and placement techniques. At occlusal margins, the traditional (experimental) composite resin restoration placed by the incremental technique showed less microleakage than did the traditional (commercial) [corrected] composite resin restoration placed by the bulk technique. In each group, the occlusal and proximal adaptations had significantly higher "excellent margin" than did the cervical adaptation. Thus, the marginal adaptation at the cervical aspect of conventional Class II composite resin restorations may present a problem with respect to microleakage.     

Influence of different restorative techniques on microleakage in Class II cavities with gingival wall in cementum

This study compared marginal leakage of Class II cavities with gingival margin in cementum using different techniques. Twenty-four recently extracted third molars were used. Proximal standard box cavities were prepared in both mesial and distal surfaces. The gingival margin was located apical to the cemento-enamel junction. All the preparations and restorations were performed by the same operator. Standard cavities were randomly divided into three groups (n = 16) and restored as follow: Group 1-light-cured composite resin; Group 2-self-cured composite resin + light-cured composite resin and Group 3-amalgam + light-cured composite resin. After polishing, the teeth were thermocycled and their gingival margins exposed to dye. Specimens were sectioned and leakage scores observed in accordance with a standard ranking. Data were subjected to statistical analysis (Kruskal-Wallis). Results showed that the amalgam/resin composite combination demonstrated the least leakage.     

The clinical performance of a posterior composite resin restorative material, Heliomolar R.O.®: 3-year report

A posterior composite resin restorative material was evaluated over a 3-year period by means of a controlled clinical trial. A total of 52 composite resin restorations and 52 amalgam alloy restorations were included in this trial, and were examined with regard to marginal integrity, surface texture, anatomical form and proximal contact with adjacent teeth. There were no significant differences in clinical performance between test and control materials, which both gave good service over the period of evaluation. Only five restorations (one of amalgam and four of composite resin) failed during the trial. Plastic replica dies were used to support the clinical examinations of the restorations, and such dies were found to be helpful.     

Microleakage of resin composite restorations with glass-ceramic inserts.

OBJECTIVE: The purpose of this study was to evaluate the effects of glass-ceramic inserts and different application techniques of resin composites on marginal leakage. METHOD AND MATERIALS: Three groups of 10 standardized, round, Class V cavities were prepared on the buccal surface of 30 extracted human molar teeth. Group 1 received resin composite restorations, placed in one increment (bulk). Group 2 received resin composite restorations that were placed in two increments, and group 3 received resin composite restorations with beta-quartz ceramic inserts. After the teeth were thermocycled and placed in 0.5% basic fuchsin for 24 hours, they were sectioned and examined for microleakage. RESULTS: On the occlusal margins, there was no statistically significant difference between the restorations placed with the incremental technique and the restorations with beta-quartz inserts. The restorations placed with the bulk technique had significantly more microleakage than did the others. On the gingival margins, the restorations with beta-quartz inserts exhibited significantly less microleakage than did the other groups. The restorations placed with the bulk technique showed significantly more dye penetration than did the others. CONCLUSION: The use of a glass-ceramic insert reduced the marginal leakage of Class V resin composite restorations.     

Four-year clinical evaluation of posterior resin-based composite restorations placed using the total-etch technique

Purpose : To report the 4-year clinical performance of posterior resin-based composite restorations placed using the total-etch technique.
Materials and Methods : Over a period of 1 year, 726 restorations (248 molars, 478 premolars; 260 Class I, 466 Class II; 540 replacements, 186 primary decay) were placed on conservative preparations, using the incremental placement technique in a clinical environment. Baseline data were collected, and the restorations were evaluated after 4 years. Z100 and Scotchbond Multipurpose (SBMP) (3M Dental Products, St. Paul, Minnesota) were used as the restorative system. The criteria evaluated were color match, marginal adaptation, anatomic form, cavosurface marginal discoloration, axial contour, interproximal contact, secondary caries, postoperative sensitivity, and tooth vitality.
Results : At baseline, 24% of the teeth restored presented postoperative sensitivity; 86% of the sensitive teeth were from the replacement group. At 4 years, all teeth were vital to cold test. Eighteen restorations (2.5%) presented clinically detectable marginal fracture. The shade was acceptable in all restorations. Cavosurface marginal discoloration was observed in 47 restorations (6.5% bravo scores). Axial contour, interproximal contact, and marginal adaptation received 100% alfa scores. No secondary caries was diagnosed in any of the teeth examined. None of the examined restorations required replacement.
CLINICAL SIGNIFICANCE
Under controlled clinical conditions, posterior resin-based composite restorations placed with the total-etch technique and restorative Z1OO/SBMP have the potential to present a high success rate at 4 years. None of the examined restorations required replacement, and there was no clinically detectable wear in any of the restorations. Simultaneous etching of enamel and dentin followed by the application of a resin adhesive can be considered an adequate modality of pulp protection in nonexposed tooth preparations.     

Effect of eugenol-containing sealer on marginal adaptation of dentine-bonded resin fillings

AIM: Eugenol is claimed to interfere with the polymerization of composite resins and to affect shear bond strengths of dentine-bonded composite restorations. Eugenol-based sealers are used during root canal treatment in teeth that may require build-ups or extensive restorations. Unfortunately, the adverse effect of eugenol has mostly been assessed in shear bond tests and this variable may be clinically inappropriate. The current study evaluate the effect of eugenol in a eugenol-based endodontic sealer on marginal adaptation of composite resin restorations with and without thermo-mechanical stress. METHODOLOGY: Thirty Class V cavities with half of the cavity margins in dentine and half of the cavity margins in enamel were prepared in extracted human premolars and then divided into 5 groups. Teeth in group 1 were not contaminated with eugenol. Cavities in groups 2-4 were contaminated with a eugenol-based sealer (Tubli-Seal, Kerr) and cleaned with: (i) sandblasting, (ii) bur finishing alone or (iii) bur finishing combined with swabbing with alcohol. These 4 groups were temporized for 6 weeks (Ketac, ESPE), whilst group 5 received no eugenol, was not temporized and acted as the control. Cavities were restored with Tetric Ceram using Syntac Classic (Vivadent) as a dentine-bonding agent. The specimens were then thermo-mechanically stressed. The percentages of marginal adaptation in dentinal and enamel margins were assessed in a SEM at x200 magnification before and after stress using a replica method. Mean percentages of marginal adaptation were calculated and compared using a two way-ANOVA (influence of eugenol and cleaning procedure) and non-parametric tests. RESULTS: Marginal adaptation in enamel exceeded 95% and 92% in all specimens before and after thermo-mechanical stress, respectively. Before stress, marginal adaptation in dentine ranged from 92.3 +/- 7.9% to 95.7 +/- 6.2% in groups 1-5. After stress, the percentage of marginal adaptation in dentine decreased significantly overall (P < 0.05, range 39.8 +/- 21.1% to 82.9 +/- 13.7%). The effect of contamination with eugenol was not significant (P > 0.05): in contrast, there was a significantly beneficial effect when the entire cavity was finished with burs (P < 0.01). CONCLUSIONS: Under the conditions of this study, the eugenol containing sealer did not significantly impair marginal adaptation in dentinal margins of mixed Class V restorations when bur finishing was employed before placement. However, no other cleaning method was sufficient to produce acceptable figures of marginal adaptation.     

The use of amalgam in pediatric dentistry

Amalgam has been widely utilized to restore posterior teeth in pediatric dentistry, and is still taught as the material of choice for Class I and Class II restorations in many dental schools in the United States and Canada. Results of clinical trials are difficult to compare due to their heterogenicity, mainly due to differences in caries risk, operator skills, study duration, or patients' age. Thus, the different studies report failure rates of amalgams ranging from 12% to over 70%. Treatment of caries should meet the needs of each particular patient, based on his/her caries risk. In general, for small occlusal lesions, a conservative preventive resin restoration, using composite or compomer in conjunction with sealant, would be more appropriate than the classic Class I amalgam preparation. For proximal lesions, amalgam would be indicated for 2-surface Class II preparations that do not extend beyond the line angles of primary teeth. This recommendation might not be appropriate for high-risk patients or for restoring first primary molars in children 4 years of age and younger where stainless steel crowns have demonstrated better longevity. Currently, amalgam demonstrates the best clinical success for Class II restorations that extend beyond the proximal line angles of permanent molars.     

Class IV preparation design for microfilled and macrofilled composite resin.

The current standard preparation for Class IV composite restorations is the placement of a bevel on all enamel margins. This study evaluated chamfered and beveled preparations for Class IV restorations of lesions with microfilled and macrofilled composite resin. Forty incisors were obtained and standardized lesions for Class IV restorations were formed. Twenty teeth had a 1.5-mm bevel placed and 20 had a 1.5-mm chamfered preparation placed. Half of the beveled and chamfered preparations were restored with microfilled composite resin; the remaining were restored with macrofilled composite resin. All restorations were fractured with an Instron Testing Machine. The mean force (lbs +/- SD) to fracture the restorations were: (beveled, microfilled composite 16.0 +/- 4.4); (chamfered, microfilled composite 30.6 +/- 20.0); (beveled, macrofilled composite 34.9 +/- 18.6); (chamfered, macrofilled composite 48.8 +/- 14.3). The chamfered preparations provided greater restoration fracture resistance than beveled preparations, for both microfilled and macrofilled composite restorations. Scheffe's test indicated traditional beveled, microfilled Class IV composite resin restorations significantly decreased fracture resistance compared to chamfered, macrofilled composite restorations (P less than 0.001).     

Marginal and internal adaptation of bulk-filled Class I and Cuspal coverage direct resin composite restorations

This in vitro study compared the marginal and internal adaptation of bulk-filled Class I and cuspal coverage direct resin composite restorations filled with different types of adhesive restorative systems and different thicknesses of bonding agent. Seventy-two intact, caries-free, freshly extracted human molars were randomly divided into 12 groups of six teeth each, according to the type of cavity (Class I [I] or Cuspal Coverage [C]), adhesive restorative system (SE Bond/Clearfil AP-X [SE] or Prime&Bond NT/Spectrum TPH [PB]) and thickness of bonding agent (normal or thick layer) in Class I restorations. Standardized Class I and Cuspal coverage cavities with enamel outer margins were prepared and restored with the corresponding type and thickness of bonding agent and respective resin composite. The resin composite was placed and polymerized in one increment (bulk filling). Dentinal fluid was simulated using 1:3 diluted horse serum and fed into the pulp chamber both during restoration and stressing. In six of the 12 groups, the restorations were subjected to 1.2 million mechanical occlusal cycles (maximum force 49 N; frequency 1.7Hz) and 3,000 simultaneous thermal cycles (5-50-5 degrees C). Marginal adaptation before and after mechanical and thermal stressing was assessed by using the replica technique and quantitative evaluation under SEM at 200x magnification. The teeth were dissected in a mesio-distal direction with a slow rotating diamond disc under water cooling, and the internal adaptation was also assessed by using the replica technique under the conditions described. Statistical evaluation of the continuous margin at the external and internal interface was performed with one-way analysis of variance (ANOVA) and Tukey's Studentized Range (HSD) test (p = 0.05). Even though Cuspal coverage restorations (SE- C: 96.89 +/- 1.83 and PB- C: 97.15 +/- 2.93) exhibited statistically significantly better external adaptation than Class I restorations (SE- I: 63.95 +/- 12.82 and PB- I 64.74 +/- 14.62) before stressing, there was no statistically significant difference after mechanical and thermal stressing (SE- C: 76.35 +/- 18.53 and PB- C: 76.02 +/- 12.49 SE- I: 54.67 +/- 10.82 and PB- I: 59.94 +/- 15.20). After stressing, SE Bond Cuspal coverage restorations (SE- C: 96,72 +/- 3,26) exhibited superior internal adaptation compared to SE Bond Class I restorations (SE- I: 57.83 +/- 12.91). No difference was observed in internal adaptation between Prime&Bond NT Cuspal coverage and Class I restorations (PB- C:36.46 +/- 21.82, PB- I: 38.71 +/- 6.76). In Class I restorations, the increased thickness in bonding did not improve the marginal and internal adaptation either before or after stressing. Bulk-filled direct resin composite Cuspal coverage restorations exhibited marginal adaptation similar to bulk-filled direct resin composite Class I restorations. The internal adaptation of Cuspal coverage SE Bond/Clearfil AP-X restorations was superior to all the other groups tested.     

Reliability of different techniques to assess marginal defects of Class II restorations in retrieved primary molars: a visual-tactile,SEM, dye penetration and polarized light microscopy study

The aims of the present article were to assess the reliability of different techniques to assess marginal defects in Class II restorations in retrieved primary molars, and to determine the degree of agreement between the various assessment modalities. The material evaluated was comprised of 18 exfoliated primary molars that had been restored 20 to 22 months previously with a resin-modified glass ionomer (Vitremer--7 teeth), a hybridized composite resin (Z100 + Scotchbond Multipurpose--9 teeth), and amalgam (Dispersalloy--2 teeth). No significant differences could be observed between the groups. The majority of the restorations rated A at the buccal and lingual margins, but poor adaptation was disclosed at the cervical margin of the three types of restorations. SEM evaluation revealed that the highest percentage of defects was seen at the cervical margins with no statistically significant difference between the groups. No or minimal leakage was present at the occlusal margins and severe penetration of dye was seen at the cervical margins in all groups. Significantly less demineralization was seen adjacent to the Vitremer and Z100 restorations when compared to the Dispersalloy but no difference was found between the esthetic restorations. Except for the visual tactile examination, small marginal defects could be disclosed by the three assessment techniques (SEM, dye penetration, and polarized light microscopy). A good degree of agreement was observed between the three evaluation techniques.     

Four-year in vivo evaluation of the composite/bonding resin-tooth interface

The objective of this study was to evaluate the color match, marginal discoloration, recurrent caries, anatomic form, and marginal adaptation of 41 paired Class III and Class V preparations restored with a conventional chemically cured resin composite with and without a low-viscosity bonding resin (LVBR). In addition, the wear of the restorations was evaluated from scanning electron micrographs of epoxy replicas of the restorations. The subjects were re-called 48 months after placement of the restorations. The marginal discoloration and wear of the composite restorations placed without a LVBR were significantly greater than in restorations placed with a LVBR. The results of this clinical study suggest that a LVBR should be applied prior to the placement of a conventional chemical-activated resin composite.