One-yer and two-year clinical evaluation of a composite resin vs. amalgam

One-Year Clinical Evaluation of Composite Restorations in Posterior Teeth: Effect of Adhesive Systems

This clinical study assessed the performance of posterior composite resins applied with the Adper™ Single Bond Plus (SB) and Adper™ Scotchbond SE (SE) adhesive systems and Filtek™ Supreme Plus composite resin, using modified US Public Health Service criteria. A total of 97 restorations were placed in posterior teeth by two calibrated operators. Application of the materials followed manufacturers' instructions. The restorations were evaluated by two examiners at baseline and after one year. Statistical analyses were conducted using the proportion test at a significance level of 5% (p<0.05). All the restorations evaluated (ie, 100%) received an alpha rating for the criteria of marginal discoloration and marginal integrity at baseline. At one year, for marginal discoloration, 64.6% of SB and 61.2% of SE received an alpha rating. For marginal integrity, 72.9% of SB and 77.6% of SE received an alpha rating. The other restorations received bravo ratings for both criteria. None of the teeth that received the restorative systems presented caries lesions around the restorations. A total of eight teeth presented postoperative sensitivity one week after baseline, five with SB and three with SE; the symptom had disappeared one year later. One year later, composite resin restorations using either adhesive system showed satisfactory clinical performance.

Comparative evaluation of combined amalgam and composite resin restorations in extensively carious vital posterior teeth: An in vivo study

Aim:

The clinical performance of the combined composite – amalgam restorations in posterior teeth was evaluated.

Materials and Methods:

One hundred carious posterior teeth were randomly divided into four groups of 25 teeth each. In Group A, the teeth were restored with composite Z250 and amalgam FusionAlloy. In Group B, composite Surefil and amalgam were used. In Groups C and D, the teeth were restored with composite Surefil and amalgam FusionAlloy, respectively. The restorations were evaluated at 3, 6, 12, and 15 months, using the Ryge criteria.

Results:

Combined restorations and amalgam restorations showed better contact and contour than the composite restorations. No statistically significant difference was observed among the groups. Three amalgam restorations exhibited loss of retention.

Conclusion:

The combined composite–amalgam restorations performed better for contact and contour and retention than composite and amalgam restorations, respectively.

Restoration of posterior teeth in clinical practice: evidence base for choosing amalgam versus composite

This article reviews the current use of amalgam versus resin composite in posterior restorations and the evidence-base for choosing between these two treatment options. While much research has been published on the issue of the clinical use of amalgam versus resin composite, there are several issues that limit the true evidence-base on the subject. Furthermore, while the majority of published studies on posterior composites would seem to indicate equivalent clinical performance of resin composite to amalgam restorations, the studies that should be weighted much more heavily (randomized controlled trials) do not support the slant of the rest of the literature. As part of an evidence-based approach to private practice, clinicians need to be aware of the levels of evidence in the literature and need to properly inform patients of the true clinical outcomes that are associated with the use of amalgam versus resin composite for posterior restorations, so that patients are themselves making informed decisions about their dental care.

Influence of water exposure on three-body wear of composite restoratives

The objective of this investigation was to study the influence of water exposure on the three-body wear of composite restoratives. A three-body wear instrumentation was used to investigate the wear resistance of five composite restoratives [Silux Plus (SX), Z100 (ZO), Ariston pHc (AR), Surefil (SF) and Tetric Ceram (TC)] with and without exposure to water. An amalgam alloy [Dispersalloy (DA)] was used as control. Ten specimens were made for each material. The specimens were conditioned in artificial saliva at 37 degrees C for 24 h and randomly divided into two groups of 5. The first group was subjected to wear testing immediately after the 24 h conditioning period, while the second group was conditioned in distilled water at 37 degrees C for 7 days prior to wear testing. All materials were wear tested at 15 N contact force against SS304 counter-bodies for 20,000 cycles with millet seed slurry as third-body. Wear depth (microm) was measured using profilometry, and results were analyzed by ANOVA/Scheffe's and independent sample t-tests at significance level 0.05. Ranking of wear resistance was as follows: without water exposure: DA > ZO > SF > AR > SX > TC; with water exposure: DA > ZO > SX > SF > AR > TC. Wear factor ranged from 2.20 for ZO to 7.13 for TC without water exposure and from 46.00 for ZO to 143.00 for TC with exposure to water. Exposure to water significantly increased three-body wear for all composite restoratives, but did not affect wear of the amalgam alloy. The effects of water exposure must be considered for the evaluation of wear in all polymeric composite restoratives.

Bruxing-type dental wear simulator for ranking of dental restorative materials

An instrumented dental wear test simulator was developed to simulate jaw movement in the chewing process between two molar teeth. It simulated the natural impact with sliding masticatory action, known as bruxing (defined as the gnashing, grinding, or clenching of teeth) type of wear, in order to simulate a worst-case dental wear scenario. In vitro wear testing of dental restorative materials was performed. Impact and sliding wear were simulated on the machine, with water as the lubricant, on three metal alloys (Tytin, Valiant Ph.D., Galloy) and three composite resins (Silux Plus, Z100, P50). The impact force for each machine cycle was brought closer to the maximum natural masticatory forces by the use of a shock absorbing layer. To replicate the natural masticatory action, the specimens had a surface profile with the shape of a conical depression. Ranking of the materials' performance on the wear test simulator was seen to be consistent with published clinical ranking. Metal alloys showed greater wear resistance than composite resins. Among the different metal alloys, those with lower hardness and compressive strengths exhibited greater wear. Composite resins with large filler particles wore worse than those with small filler particles. Results were compared with previous work on impact with sliding on a flat surface without a cushioning layer. It was concluded that the magnitude of the impact force and the angle of approach during impact with sliding wear are important parameters in the in vitro wear ranking of dental restorative materials.

Seventeen-year clinical study of ultraviolet-cured posterior composite Class I and II restorations

OBJECTIVES

To compare the clinical performance of four commercial ultraviolet light-cured composite materials, and to evaluate curing-system effects on long-term wear resistance of Class I and II restorations.

MATERIALS AND METHODS

Approximately 32 samples of each of four different ultraviolet light-cured composites (n = 130) were inserted into conventional Class I and II cavity preparations by two clinicians. Cavosurface margins of the preparations were not beveled. Enamel walls of the preparation were etched, and the respective bonding agent was applied. Each restoration was evaluated by two clinicians at 5, 10, and 17 years. Direct evaluations were performed using modified United States Public Health Service (USPHS) criteria. Indirect evaluations were performed using the Leinfelder cast evaluation method.

RESULTS

After 17 years, 65% of the restorations were recalled and pooled direct evaluations were conducted for color matching (94% alfa), marginal discoloration (100% alfa), marginal integrity (100% alfa), secondary caries (92% alfa), surface texture (72% alfa), and anatomic form (22% alfa). Mean occlusal wear from indirect evaluations at 5, 10, and 17 years was 197 +/- 85 microns, 235 +/- 72 microns, and 264 +/- 80 microns, respectively. For direct and indirect evaluations there were significant differences (p < or = .05) between the baseline and 5-year recall evaluations.

CLINICAL SIGNIFICANCE

This study demonstrated that the mean pooled occlusal wear of four ultraviolet light-cured posterior composites at 17 years was 264 microns (approximately 0.25 mm), and that most wear (75%) occurred in the first 5 years. Of all recalled restorations, 76% were judged clinically acceptable at 17 years, and 22% of those exhibited no clinically detectable wear.

Benefits and disadvantages of tooth-coloured alternatives to amalgam

OBJECTIVES

To give the practising dentist scientifically based data to assist him/her in the responsible decision-making process necessary to weigh the options available to the patient if she/he prefers not to have an amalgam placed.

DATA SOURCES

Based on the literature and on the research work, which was done in the author's department, the indications and limitations of the known alternatives of amalgam were formulated. DESCRIPTION OF ALTERNATIVES TO AMALGAM: With the exception of cast gold restorations, all alternatives require the strict use of adhesive techniques. When compared with similar amalgam restorations, placing composite restorations (if they are indicated) takes approximately 2.5 times longer because complex incremental techniques are needed. Despite all the efforts, direct composite restorations placed in large cavities still show unacceptable amounts of marginal openings. Tooth-coloured inlays are a better alternative for large restorations. These restorations must be inserted with adhesive techniques. With composite inlays it is difficult to achieve a composite-composite bond. Ceramic inlays may be micromechanically bonded to the luting composite. They all show clinically a good marginal behaviour and the use of ultrasonic energy may further simplify the application technique of aesthetic inlays.

STUDY SELECTION

Papers describing the different techniques were used as a base for the corresponding chapter. To assess and compare the longevity of the different restoration types, literature data were used. We limited ourselves to papers reporting at least 5-year clinical data. Longitudinal, clinically controlled studies were preferred. However, to be more complete, retrospective, cross sectional studies were also included. LONGEVITY OF POSTERIOR RESTORATIONS: Amalgam shows excellent longevity data with studies up to 20 years. The average annual failure rate is 0.3-6.9%. Posterior composites are in the same range (0.5-6.6%), however, the study times are much shorter (max. 10 years). For tooth-coloured inlays much less data are available. Longevity is reported up to 6 years with annual failure rates of 0.6-5%.

CONCLUSIONS

All aesthetic alternatives to amalgam require more complex procedures and more time. If cost benefit considerations are a concern, amalgam is still the most convenient restorative material for posterior teeth.

An accurate and simple method for the measurement of dental composite wear

This study describes a relatively simple mechanical technique for measuring occlusal wear at the margin of dental restorations. The device was essentially a custom profilometer which consisted of a linear variable differential transformer with its core supported by double cantilever springs, a specially shaped stylus, a motor driven microscopic stage, custom computer software utilizing a colour coding to separate differences in slope, and a cross-hair-shaped mouse cursor to differentiate the boundary of wear. Two sets of visual standard stone casts were evaluated. The first set consisted of 17 stone replicas of machined steel dies and the second set consisted of five clinical casts, which have been used to measure the wear of composite restorations by direct vision. The reproducibility found when measuring the stone replicas of the machined steel dies was 2 microns, while, for the clinical standards, it was 16 microns.

Visual versus mechanical wear measurement of dental composite resin

This study compares a visual method for measuring composite wear with a relatively inexpensive mechanical technique. The visual measurements used a set of 17 graduated stone standards as the reference. Two sets of 10 unknown casts were evaluated. The first was a set of 10 stone replicas selected from the reference set in the range of 25-250 microns. The second set was composed of 10 casts of clinical restorations. The mechanical test employed a computer-controlled custom profilometer. Depth was recorded at 50 equidistant positions around the margin. A significant correlation was found (r > 0.98) between the visual and mechanical means for both measurement techniques. Mean values were equivalent for the standard casts. However, visual estimation of the clinical casts were significantly lower (61% of mechanical values) and thus not accurate for clinical use.

Assessing the long-term effect of a surface penetrating sealant

Small defects are commonly found on the surfaces of composite restorations--especially in stress-bearing areas. Sealant application may reduce the wear rates of these restorations. This five-year study assesses the effect of sealant application on interfacial staining, clinical wear, marginal integrity and surface texture.

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.

Five-year clinical study of u.v.-polymerized posterior composites

Four u.v.-polymerized composites (Estilux, Nuva-Fil, Nuva-Fil P.A. and Uvio-Fil) were clinically evaluated in Class I and II cavity preparations in permanent teeth. The restorations were evaluated at baseline, 1, 2, 3, 4 and 5 years using USPHS criteria for direct evaluation and at 3, 4 and 5 years using the Leinfelder method for indirect evaluation of wear. The wear measured by the USPHS method showed increasing wear rates in earlier reports, apparently due to the limited sensitivity of the scale to early wear. The wear by the Leinfelder method showed gradually decreasing wear rates. There were no statistically significant differences among the wear values for the four u.v.-cured materials or between these materials and the self-cured and visible light-cured controls.

Microhardness of Class II composite resin restorations with different matrices and light positions

The degree of polymerization, determined by surface hardness, has been related to the gingival marginal adaptation of posterior composite resin restorations. Poor marginal adaptation results from marginal leakage and failure of the restoration. This study compared the degree of polymerization, measured by microhardness, of a microfilled composite resin placed by use of different matrices. The effect on polymerization with the curing light in two positions was also evaluated.

A 5-year study comparing a posterior composite resin and an amalgam

Eighty class I and class II light-cured posterior composite resin restorations were compared with 43 class I and class II amalgam restorations during a 5-year period after placement. The results of this clinical study showed that both materials were satisfactory during the time period and that the only significant statistical differences are a poorer marginal integrity for the amalgam and a greater wear rate for the composite resin.

Posterior adhesive composite resin: a historic review

Since development of the BIS-GMA composite resin, there have been many innovations to improve the physical properties for posterior use. Subsequent development of a caries detector and chemically adhesive composite resin has further revolutionally raised the value of composite resin restoration, replacing the traditional restorative system of mechanical approach by the new system of biological approach. In this system only the infected irreversibly deteriorated insensitive tissue, stainable with the caries detector, is removed painlessly. The cavity is immediately filled with the composite resin with no further tissue reduction for retention or resistance form or extension for prevention. Both enamel and dentin walls are etched by a single etchant without lining. The chemical adhesion to the cavity margin and wall minimizes the marginal failure in size and prevalence and prevents secondary caries penetration along the wall. The chemically adhesive composite resin is thus a useful restorative material much kinder to teeth than amalgam.

A combined amalgam and composite resin restoration

Difficulties with restoring class II cavities with posterior composite resin are enumerated. The problem is especially acute when a gingival margin lies close to or apical to the cementoenamel junction. A technique is described whereby the proximal portion of class II cavities is restored with amalgam to the contact area and composite resin inserted in the remainder of the cavity. Microleakage was studied by dye penetration tests. At the composite resin/cementum interface microleakage was significantly greater than at the amalgam/cementum and amalgam/composite resin interfaces (p less than 0.001). No statistically significant difference was observed in microleakage between the amalgam/cementum and amalgam/composite resin interfaces.

Wear of materials used in dentistry: a review of the literature

This is a review of the literature concerning wear related to the following materials used in dentistry: dental amalgam, composite resins, and glass-ionomer cements, as well as natural tooth substance. Discussions are included on both in vivo and in vitro studies in which various methods were used to help determine wear resistance.

The clinical evaluation of heat-treated composite resin inlays

Laboratory research indicates the physical properties of composite resin used for posterior restorations can be significantly increased if a secondary dry heat treatment of the material was accomplished. This study investigated the clinical performance of a heat-treated composite resin inlay, using both the direct and indirect methods of clinical evaluation. Contrary to laboratory results, no significant differences in wear could be measured between conventional light-cured inlays and those with secondary dry heat treatment. Other clinical advantages of the heat-treated inlays were observed.

Wear of composite resin in vitro: a testing machine with rubber plate. Preliminary results

A new machine was developed to study the wear of dental filling materials in vitro. Four products: amalgam, Adaptic, Clearfil and acrylic resin were tested. Wear was measured quantitatively by weighing the specimen, and the wear pattern was studied qualitatively with a scanning electron microscope (SEM). A comparison was made with materials that were placed in the mouth for a prolonged period. It was found that the in vitro wear pattern was comparable to that found in vivo.

Wear of dental restorative and prosthetic materials in vitro

The aim of this study was to evaluate the wear of some modern materials for fixed crown and bridge restorations and fillings in vitro. Eighteen commercial materials (8 composites, 4 alloys, 4 façade materials, and 2 denture-base resins) were tested. Enamel was used as the control. Test specimens were abraded on abrasion discs under water or in artificial saliva. There was a great variation in the wear rates of the tested materials. The greatest wear was shown by resins used for base material and the smallest by gold and Cr-Co alloys and porcelain. Most of the composites had a wear rate near that of enamel. The wear for amalgam was slightly greater than for most of the composites. When one is using several different materials for reconstructing occlusion, differences in wear resistance should be taken into account.

Clinical evaluations of composite resin restorations in primary molars: a 4-year follow-up study

A total of 96 composite resin restorations were placed in primary molars. After 4 years, 44 restorations were examined. The wear rate was similar to that of enamel in primary molars. The material had excellent radiopacity and color-matching properties.

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.

Current developments in posterior composite resins

The use of posterior composite resins has grown at a rapid rate. While the original materials were completely inadequate for the restoration of Class I and II cavity preparations, the newer-generation materials are apparently superior. While wear rates of over 100 μm per year were not uncommon, some of the newer composites wear away at the rate of less than 1 μm per month.

A great deal of the improvement in wear resistance can be attributed to an optimization of the filler particle. Specifically, the particle size has been decreased and the filler loading has been increased. In some instances, softer filler particles have been incorporated in order to decrease the hardness differential between the filler and the resin matrix. Other factors which have been considered include chemical erosion of the matrix, degradation of the silane coupling agent, internal porosity, method of polymerization, and hydrophobicity of the resin matrix.

A greater understanding has been developed regarding patterns of wear as well as rates of wear. Techniques have been developed for rapid and routine measurements of the loss of anatomical form. Although the composite resins have been improved substantially, their use in posterior teeth is quite technique-sensitive. Furthermore, the problem of secondary caries is still a major concern.

Cavity design for class II composite restorations

Preparation design for posterior composite restorations should differ from that for amalgam restorations in the following manner. Occlusal form should be narrower and the depth shallower. The proximal extensions (facial and lingual) should be placed in areas that can be seen, probed, and polished. Internal line angles should be rounded and retenive grooves placed in proximal line angles (axiofacial and axiolingual) and the gingival wall. Beveling is recommended for proximal margins but not for occlusal margins.

Effects of composite restorations on resistance to cuspal fracture in posterior teeth

A clinically acceptable MOD cavity preparation was used instead of a jig-mounted slot preparation in this investigation. Each preparation was proportional to the tooth dimension. The design of the testing instrument ensured that forces applied to the specimens were applied to tooth structure and not to the restorative material. Prepared unrestored teeth were weaker than restored teeth. No significant difference was noted in fracture resistance between teeth restored with amalgam and with composite resin. The method used in this study is replicable, allowing the possibility of comparison studies by using identical procedures. Future research will focus on issues of polymerization method and modulus of elasticity and their effects on fracture resistance of remaining tooth structure.

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.

Clinical behavior of composite resins

Since the original development by Bowen in the 60's, composite resins have evolved into a widely used and successful restorative material. Although they exhibit certain inadequacies as a dental restorative material, improvements constantly are being made. Due to the aesthetic nature of the material, coupled with its potential for mechanical and chemical bonding to tooth structure, composite resins will become more broadly used in the future.

A high-copper amalgam evaluated after three years in city and country practices

The objective of the study was to compare the condition of Sybraloy restorations placed by the same operator in two different practice locations. Evaluations of the restorations were based on assessments for marginal fracture and staining, and for surface discoloration and roughness. Sybraloy restorations placed in a city practice were more satisfactory than those placed in a country practice. Surface discoloration proved to be unsatisfactory, especially in the country practice, but could be removed with light polishing.

Wear rates of posterior composite resins

The wear rates of nine posterior composite resins were determined for a period of up to 3 years. The wear rates observed depended on the method used for evaluation. A quantitative method of evaluation showed that the wear rates decreased with time. With the use of the quantitative measurements obtained at the end of 6 months after insertion, it was possible to predict the average annual rates of wear at the end of 3 years.

A visible light-cured posterior composite resin: results of a 3-year clinical evaluation

Seventy-nine Class I and II light-cured composite resin restorations were evaluated for 3 years. Although the composite resin was not totally wear resistant, its overall clinical performance was acceptable, relative to most parameters of evaluation. The use of such a material in the posterior region may be justified in situations in which appearance is important, ideal circumstances predominate over conservative cavity design, and the patient understands the benefits and limitations of the procedure.

Two-year clinical evaluation of light-cured composite resin restorations in primary molars

The restorations were evaluated at baseline, and at 6, 12, and 24 months by two trained examiners. In the system used, the highest, most desirable rating is Alfa. Of the restorations evaluated at 24 months, 99% had Alfa ratings for color match, 87% had Alfa ratings for no discoloration at cavosurface margins, and 86% had Alfa ratings for no loss of anatomic form. In addition, 75% of the restorations had Alfa ratings for margin adaptation, and 91% had Alfa ratings for no recurrent caries at the 24-month evaluation. In conclusion, the light-cured composite resin restorative material functioned well at the 12- and 24-month evaluation periods, when used in primary molars.

Measurement of the rate of wear of dental composite resins by a 90Sr beta particle transmission gauge

The wear rate of restorative dental composite resins is an important parameter in the assessment of their in vivo performance. The two more widely used methods of quantifying wear are measuring the dimensional change and measuring the change in the mass of the specimen. The former method is complicated by uneven wear of specimens and presents difficulties with samples of irregular shape, and the latter method involves measurements of changes in mass as small as tens of micrograms with specimens of sizes similar to those encountered clinically. A 90Sr beta particle transmission gauge has been designed and constructed to enable the wear rate of small specimens of dental composite resins to be measured. The 90Sr beta particle transmission gauge enables indirect measurements of changes in mass to be made and overcomes some of the difficulties inherent in the direct measurement of mass and length. Applications of the 90Sr beta particle transmission gauge to the measurement of wear rates are given for restorative dental resins having a range of inorganic filler contents and types. The results show that the 90Sr beta particle transmission gauge is capable of measuring the rate of wear to a degree of precision similar to that of micrometer-derived measurements.

Three-year clinical study of UV-cured composite resins in posterior teeth

Four proprietary composite resins cured with ultraviolet light were inserted into Class I and II cavity preparations. The restorations were evaluated over a 3-year period for color match, interfacial staining, secondary caries, loss of anatomic form, marginal adaptation, and surface texture. The percent of restorations exhibiting no generalized loss of anatomic form ranged from 47% to 93%.

A clinical evaluation of occlusal composite and amalgam restorations: one- and two-year results

A two-year study was conducted to compare the qualitative advantages, if any, of a conventional, cold-curing composite resin to amalgam in occlusal Class I cavities in posterior teeth. The composite was placed into modified, conservative cavity preparations using the acid etch technique. Sixty-one pairs of contralateral restorations were evaluated. Forty-six percent of the amalgams and 42.6% of the composites were considered sound. The major deficiency of each material was rough or chipped margins of the amalgams (38%) and worn surfaces of the composites (26%). The use of conservative cavity preparations and the acid-etch technique with bonding agent and final glaze improved the longevity of the composite restorations compared to previous studies. However, the improvement does not suggest that this method will have a long-term effect on clinical success nor does it indicate that composite is superior to amalgam other than in marginal integrity and esthetics.

A silver staining technique for investigating wear of restorative dental composites

A silver staining technique was developed to demonstrate microdefects in dental restorative composites. Fine silver particles were preferentially introduced into the damaged region to provide optical contrast between the damaged and the undamaged regions. The amount of silver deposition determined with an electron probe microanalyzer, provided an indication of the extent of damage within the dental composites. Examples to demonstrate this technique were given with one clinically worn dental composite restoration and one in vitro worn composite sample.