An alternative method to reduce polymerization shrinkage in direct posterior composite restorations

BACKGROUND: Polymerization shrinkage is one of dental clinicians' main concerns when placing direct, posterior, resin-based composite restorations. Evolving improvements associated with resin-based composite materials, dental adhesives, filling techniques and light curing have improved their predictability, but shrinkage problems remain. METHODS: The authors propose restoring enamel and dentin as two different substrates and describe new techniques for placing direct, posterior, resin-based composite restorations. These techniques use flowable and microhybrid resin-based composites that are polymerized with a progressive curing technique to restore dentin, as well as a microhybrid composite polymerized with a pulse-curing technique to restore enamel. Combined with an oblique, successive cusp buildup method, these techniques can minimize polymerization shrinkage greatly. CONCLUSIONS: Selection and appropriate use of materials, better placement techniques and control polymerization shrinkage may result in more predictable and esthetic Class II resin-based composite restorations. CLINICAL IMPLICATIONS: By using the techniques discussed by the authors, clinicians can reduce enamel microcracks and substantially improve the adaptation of resin-based composite to deep dentin. As a consequence, marginal discoloration, recurrent caries and postoperative sensitivity can be reduced, and longevity of these restorations potentially can be improved.     

Clinical evaluation of packable and conventional hybrid resin-based composites for posterior restorations in permanent teeth: results at 12 months

BACKGROUND: Packable resin-based composites and simplified resin bonding systems are marketed to offer many advantages over conventional posterior hybrid composites and total-etch bonding systems. The authors conducted a study to evaluate the initial clinical performances of a packable and a conventional hybrid resin-based composite used with a simplified bonding system. METHODS: A total of 57 Class I and 45 Class II restorations were placed in the permanent teeth of 65 adult patients. The carious lesions were restored with either packable resin-based composite (SureFil, Dentsply DeTrey GmbH, Konstanz, Germany) or conventional hybrid resin-based composite (SpectrumTPH, Dentsply DeTrey GmbH), using a resin adhesive (Non-Rinse Conditioner and Prime & Bond NT, both manufactured by Dentsply DeTrey GmbH). The authors evaluated the restorations using U.S. Public Health Service-Ryge modified criteria (in which Alfa is the highest rating) and by using color transparencies and die stone replicas. RESULTS: Three SureFil restorations failed before their baseline evaluation. There were no failures among the 78 SpectrumTPH restorations evaluated at 12 months. For both resin-based composites, Alfa ratings were 90 percent or higher for marginal discoloration, anatomical form, surface texture and surface staining. Lower percentages of restorations were rated Alfa for color match, marginal integrity and gingival health. Occasional mild postoperative sensitivity was reported for four SureFil restorations and one SpectrumTPH restoration. The mean occlusal wear rate was 38 micrometers for the larger SureFil restorations and 25 microm for the smaller SpectrumTPH restorations. CONCLUSIONS: The 12-month clinical performances of the two restorative materials were satisfactory and not significantly different for each of the parameters evaluated. CLINICAL IMPLICATIONS: A packable and a conventional hybrid resin-based composite placed with a simplified bonding system in posterior permanent teeth showed satisfactory and similar results after 12 months.     

Two-year clinical evaluation of a packable resin-based composite

BACKGROUND: Packable resin-based composites were introduced in 1998, but few clinical studies have been conducted to evaluate them. The authors conducted a clinical study to determine the two-year performance of SureFil (Dentsply DeTrey GmbH, Konstanz, Germany) packable posterior resin-based composite in Class I and II restorations. METHODS: An operator (L.S.T.) restored 55 cavities in 36 patients (16 Class I restorations and 39 Class II restorations). After cavity preparation, she etched the enamel with 34 percent phosphoric acid, applied Prime & Bond NT (Dentsply DeTrey GmbH) to dentin and etched enamel for 20 seconds and then cured it for 20 seconds. She restored the cavity using 3- to 5-millimeter increments of SureFil. Independent examiners assessed the restorations after placement and at six months, one year and two years for color matching, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomical form and postoperative sensitivity, using the Ryge criteria. RESULTS: The authors assessed the changes in the parameters during the two-year period using a software program with Friedman test analysis with a Bonferroni adjustment at significant level of P = .05. At baseline, 31 restorations were graded as Bravo for color match. At the six-month and one-year recall periods (n = 55), 53 restorations remained unchanged. Two restorations from the same patient fell out after one month. After two years (n = 50), there were five Bravos for surface staining and three for marginal adaptation (P < .05). CONCLUSION: After two years of clinical service, SureFil packable resin-based composite had a success rate of 96 percent, and the authors considered it successful in Class I and II restorations. CLINICAL IMPLICATIONS: SureFil packable resin-based composite can be successful in clinical situations with limited-sized cavities and proper application of restorative techniques.     

A clinical evaluation of resin-based composite and glass ionomer cement restorations placed in primary teeth using the ART approach: results at 24 months

BACKGROUND: The authors evaluated the 24-month performance of a packable resin-based composite/dentin bonding system and a high-viscosity glass ionomer cement (GIC) in restorations placed in primary molars with the atraumatic restorative treatment (ART) approach. METHODS: Three dentists placed 419 restorations in 219 children aged 6 through 10 years who had bilateral matched pairs of carious posterior Class I and II primary teeth. They used a split-mouth design to place the two materials, which were assigned randomly to contralateral sides. The authors evaluated the restorations according to U.S. Public Health Service Ryge criteria. RESULTS: After 24 months, 96.7 percent of the Class I GIC restorations and 91 percent of the resin-based composite restorations survived, while the success rates for the Class II restorations were 76.1 percent and 82 percent for the GIC and resin-based composite restorations, respectively. The survival rate of the Class II resin-based composite restorations was 5.9 percent higher than that of the GIC restorations at the 24-month evaluation, but this difference was not statistically significant. However, the study results showed a statistically significant difference in survival rates between Class I and II restorations for both materials. CONCLUSION AND CLINICAL IMPLICATIONS: The two-year clinical performance of both materials was satisfactory for the restoration of Class I and II primary molars using the ART approach.     

The benefits of glass ionomer self-adhesive materials in restorative dentistry

Bonded, resin-based composite restorative materials have potential advantages. If the dentin bond achieved is not greater than the polymerization stress, loss of retention is likely, resulting in areas of microleakage and postoperative sensitivity. Class 5 lesions restored with no preparation have been used for testing the clinical performance of new adhesive restorative systems. Laboratory studies have demonstrated that bond strength varies according to the depth of dentin and the degree of calcification. Until the later generations of dentin bonding agents, retention rates for bonded, resin-based composites were typically more erratic and lower than glass ionomer (GI) and resin-modified glass ionomer (RMGI) restorative materials. Providing stress relief during setting is inherent in GI and RMGI materials, which helps to explain their good retention rates, despite their low bond strengths. GI and RMGI liners and lightly filled resin bonding agents provide similar stress relief. Current evidence supports the use of both RMGI and composite restorations placed with a liner of lightly filled resin in adhesive Class 5 restorations. Bonded, resin-based composite has the advantage of finishing to a high-gloss surface, making it more acceptable in areas of the mouth that are highly visible.     

Resin-based composites and compomers in primary molars

Resin-based composite resins and polyacid-modified resin-based composites (compomers) have become popular for the restoration of primary anterior and posterior teeth. In some European countries, resin-based composites or glass-ionomers are the materials of choice for primary teeth because of the controversy over dental amalgam and its alleged adverse health effects resulting from the release of mercury, although a clear correlation between amalgam restorations and health has not been determined. Another reason for the worldwide increased use of resin-based composites and glass-ionomers in pediatric dentistry could be attributed to the growing demand from parents to provide esthetic restorations to their children. More conservative preparations can be performed maintaining more tooth structure because of the adhesive properties of the composites and compomers. The most conservative treatment planning and meticulous care in the placement of the resin-based composites and compomers would produce long-term satisfactory results. These restorations should be placed in patients with low-to-moderate caries risk, and after placement the restorations should be monitored carefully to avoid complications mainly produced by recurrent caries and wear.     

A two-year comparison of resin-based composite tunnel and Class II restorations in a randomized controlled trial

PURPOSE: To evaluate the performance of total tunnel restoration with resin-based composites compared to Class II resin-based composite restorations in a randomized controlled clinical study. METHODS: 63 approximal carious lesions were restored in 38 patients by two experienced operators. The carious dentin and approximal demineralized enamel were completely removed for the tunnel restoration leaving the marginal ridge intact. The occlusal opening was enlarged to the center of the tooth to make access easy. Conservative cavity preparation was performed for the Class II restorations. All cavities were restored with Scotchbond Multipurpose Plus and Z250. At baseline, 1- and 2-year recalls, the restorations were evaluated clinically by two examiners using a modified USPHS rating system and radiographically for recurrent, caries. RESULTS: Both types of restorations performed well clinically, and there was no significant difference (P> 0.05) by the chi square test in any category. Recurrent caries was not detected. Only one tunnel restoration had to be replaced with a Class II restoration because of falling of the restoration with the marginal ridge after 2 years. However, no significant difference in the survival rates (P> 0.05) could be demonstrated between the restorations by the log-rank test.     

Clinical evaluation of packable and conventional hybrid posterior resin-based composites: results at 3.5 years

BACKGROUND: The authors evaluated clinical performances of a packable and a conventional hybrid resin-based composite used with a self-etch adhesive system. METHODS: Three dentists placed 105 posterior restorations in 65 adults. They placed a packable (SureFil, Dentsply DeTrey GmbH, Konstanz, Germany) and a conventional (Spectrum, Dentsply DeTrey GmbH) resin-based composite using a self-etch resin adhesive system. The authors evaluated the restorations using Ryge modified criteria, photographs and die stone replicas. RESULTS: After 3.5 years, six large SureFil and two Spectrum restorations had failed from bulk fracture and secondary caries, resulting in cumulative survival rates of 81.3 and 92.0 percent, respectively. Failed SureFil restorations generally were larger than the remaining intact restorations. Other ratings were satisfactory, with no significant differences between the two materials for any restoration parameter. Alfa ratings for both materials were approximately 80 percent or greater for marginal discoloration, anatomical form, surface texture and surface staining. Lower percentages of restorations were rated Alfa for color match, marginal integrity and gingival health. No postoperative sensitivity was reported. Net mean occlusal wear (+/- standard deviation) was 28.9 (+/- 32.9) micrometers for SureFil and 33.8 (+/- 29.6) microm for Spectrum restorations; the difference was not statistically significant. CONCLUSIONS: When used with a self-etch adhesive, the 3.5-year clinical performances of both composites were similar and satisfactory for the restoration of Class I and moderate-sized Class II cavities. Clinical Implications. The two composites placed in this study have an increased risk of bulk fracture when placed in large intracoronal Class II molar preparations.     

Five-year study of Class II restorations in permanent teeth using amalgam, glass polyalkenoate (ionomer) cermet and resin-based composite materials

The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cermet material and a resin-based composite material used in small Class II cavities in permanent teeth. All restorations were inserted under rubber dam. They were examined yearly for 3 years. One clinician continued the study up to 5 years. The clinical examination focused on two criteria: clinically acceptable and failure. In addition, impressions were taken of the prepared cavities immediately before restoration and at each clinical examination using an elastomeric material. The study comprised 274 Class II restorations (88 amalgams, 95 cermets and 91 resin composites) placed in 142 adolescent patients. One hundred and sixty-seven restorations were in molar and 107 in premolar teeth. Patient dropout after 5 years resulted in the loss of 161 restorations, evenly distributed for restorative material and type of tooth involved. Four amalgam restorations, 22 glass ionomer cermet and nine resin composite restorations failed. The glass ionomer cermet and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.     

Influence of the isolation method on the 10-year clinical behaviour of posterior resin composite restorations

The aims of this prospective randomised clinical study were to clinically evaluate a radiopaque, highly filled, hybrid, light-activated resin-based composite for posterior teeth (Occlusin, ICI Dental, Macclesfield, UK and GC Dental, Tokyo, Japan) and compare the performance of restorations placed using rubber dam or cotton roll isolation. One clinician placed 100 (42 Class I and 58 Class II) restorations of the material under investigation. The isolation mode for each restoration was determined randomly: 52 preparations were protected from contamination with cotton rolls and aspiration, and 48 preparations were isolated under rubber dam. At baseline and periodically thereafter (0.5, 1, 2, 3, 4, 5, 6, and 10 years), each composite was evaluated by two practitioners using a modified (USPHS) rating system. After 10 years, 37 restorations were reviewed. The results showed satisfactory clinical performance with and without rubber dam after 10 years. A concern was the number of failures at 10 years due to unsatisfactory proximal contact. The evaluations for the surviving restorations were acceptable but with a large reduction in the percentage with ideal occlusal and proximal anatomy. The 10-year comparison of isolation modes showed no statistically significant differences (Kruskal-Wallis test) for each of the evaluation criteria. Furthermore, survival analysis showed no significant difference between the groups (Mantel-Haenszel method). It was concluded that the 10-year clinical behaviour of the restorations of a posterior composite placed under well-controlled, effective isolation with cotton rolls and aspiration, was not significantly different from the behaviour of restorations placed using rubber dam isolation. Received: 7 February 2000 / Accepted: 8 March 2000     

Using packable composites for direct posterior placement

BACKGROUND: Although dentists have been using resin-based composites successfully to restore posterior teeth in Class II situations for several years, creating a functional, anatomical proximal contact remains a clinical challenge for many clinicians. OVERVIEW: This article presents a step by-step technique for creating a predictable proximal contact using a packable resin-based composite as the restorative material. Using a technique that is similar to that for amalgam will enable the dentist to make a successful transition to using composite as an alternative to amalgam in some posterior teeth. PRACTICE IMPLICATIONS: More patients today are well-informed about dental care and are seeking tooth-colored restorative alternatives. Excellent materials and proven techniques are making the transition from traditional metallic restorations easier and more predictable. With this article, the authors aim to help dentists gain confidence in their technique and enable them to provide this service for their patients.     

Teaching the placement of posterior resin-based composite restorations in U.S. dental schools

BACKGROUND: In light of the increased use of and demand for posterior resin-based composite restorations in dental practice, the authors investigated U.S. dental schools' current teaching with regard to placement of posterior composite restorations. METHODS: In early 2005, the authors invited 52 schools to participate in an e-mailed survey. RESULTS: The authors received 47 completed responses, for a 90 percent response rate. Although all schools provided didactic and clinical teaching in the placement of occlusal resin-based composites in posterior teeth, the survey results showed variation in teaching the use of two- and three-surface occlusoproximal composites. CONCLUSIONS: The survey findings demonstrate a marked change in instruction in placement of posterior resin-based composite restorations in U.S. dental schools during the last five to 10 years. However, the authors found much variation in the nature and extent of the instruction and techniques taught. CLINICAL IMPLICATIONS: Dental schools need to ensure that their graduating students are well-prepared for independent clinical practice.     

Minimally invasive management of dental caries: contemporary teaching of posterior resin-based composite placement in U.S. and Canadian dental schools

BackgroundResin-based composites are an increasingly popular material for restoring posterior teeth, permitting minimally invasive cavity preparations and esthetic restorations. The authors investigated current teaching of the placement of posterior resin-based composites in U.S. and Canadian dental schools.MethodsIn late 2009 and early 2010, the authors, with the assistance of the Consortium of Operative Dentistry Educators (CODE), invited 67 dental schools to participate in an Internet-based survey.ResultsThe response rate was 73 percent. Although all schools taught the placement of resin-based composites in occlusal and most occlusoproximal cavities, eight schools (16 percent) did not teach placement of three-surface occlusoproximal resin-based composite restorations in permanent molars. Resin-based composites accounted for 49 percent of direct posterior restorations placed by dental students in 2009 and 2010, a 30 percent increase from 2005.ConclusionsTeaching placement of posterior resin-based composites continues to increase in dental schools in the United States and Canada, with predoctoral students gaining, on average, an equal amount of experience placing posterior resin-based composites and amalgams in terms of numbers of restorations.Clinical ImplicationsEvidence-based, up-to-date teaching programs, including those in operative dentistry, are needed to best prepare students for careers in dentistry.     

A review of polymerization shrinkage stress: current techniques for posterior direct resin restorations

In general excellent results cannot be guaranteed when using resin-based composites for posterior restorations. This is due to polymerization shrinkage which can still be regarded as the primary negative characteristic of composite resins. A review of available literature regarding the polymerization process, its flaws, and suggested strategies to avoid shrinkage stress was conducted. Several factors responsible for the polymerization process may negatively affect the integrity of the tooth-restoration complex. There is no straightforward way of handling adhesive restorative materials that can guarantee the reliability of a restoration. At present, the practitioner has to coexist with the problem of polymerization shrinkage and destructive shrinkage stress. However, evolving improvements associated with resin-based composite materials, dental adhesives, filling, and light curing techniques have improved the predictability of such restorations. This critical review paper is meant to be a useful contribution to the recognition and understanding of problems related to polymerization shrinkage and to provide clinicians with the opportunity to improve the quality of composite resin restorations.     

Preventing postoperative tooth sensitivity in class I, II and V restorations

Postoperative tooth sensitivity in Class I, II and V resin-based composite restorations continues to be an unpredictable problem in dentistry. In spite of meticulous use of dentin bonding agents, dentists and patients are faced with the sensitivity problem and the frustrating need to remove restorations and occasionally accomplish endodontic therapy on teeth that were not sensitive before the restorations were placed. Practitioners have developed numerous preventive methods to overcome the sensitivity challenge, which I have described in this article.     

One-year retrospective clinical evaluation of hybrid composite restorations placed in United Kingdom general practices.

OBJECTIVE: The purpose of this study was to assess Pertac II restorations placed in general dental practice. METHOD AND MATERIALS: A total of 86 restorations (14 Class I, 10 Class II, 17 Class III, 5 Class IV, and 40 Class V) using a hybrid composite material (Pertac II) placed in 56 patients (mean age, 39 years) in 5 dental practices in the United Kingdom were assessed after 1 year by a trained evaluator and the dental practitioner who had placed the restoration. All the restorations were assessed for anatomic form, marginal adaptation, surface roughness, sensitivity or discomfort, gingival condition, and the presence or absence of secondary caries. RESULTS: Thirty-five (43%) restorations were placed in load-bearing situations, 9% of which were assessed as being in "heavy" occlusion. Five (6%) of the restorations were lost (all Class V restorations), 4 from premolars and 1 from a molar. Four were in wedge-shaped cavities and 1 small restoration was actually dislodged during examination. The remaining 81 (94%) restorations were found to be intact, with no secondary caries detected. A high percentage of optimal scores were recorded for both anatomic form and surface roughness. CONCLUSION: It is concluded that the evaluation demonstrated satisfactory clinical performance of Pertac II restorations after 1 year of clinical service in the wide variety of clinical situations seen in general dental practice. However, the potential for failure of hybrid composite materials in Class V situations appears high. It may be argued that clinicians who wish to use a resin-based material in a Class V situation should use a compomer or microfilled composite.     

Duplicating the form and function of posterior teeth with Class II resin-based composite

The most common material used to fill Class II restorations in posterior teeth is resin-based composite (RBC). Despite the popularity of RBC restorations, there are challenges to placing them properly. Improperly shaped restorations with sharp edges and corners will chip and fracture, resulting in premature failure. Properly placed RBC restorations will duplicate the embrasures, contact area, marginal ridge, and occlusal fossa of natural teeth. RBC restorations should mimic the smooth and rounded contours of the natural dentition to ensure longevity.     

Use of a visible light cured elastomeric resin to stabilize cervical matrix in restoration of Class V erosion lesion

Effective moisture control and gingival retraction are essential prerequisites for success in the restoration of Class V bonded restorations. Various techniques exist for cervical isolation and moisture control in Class V restorations. This case report details a modified technique in which a visible light cured elastomeric resin was utilized to stabilize a cervical matrix in restoration of a Class V erosion lesion. The resultant customized matrix provides effective isolation, moisture control, and gingival retraction when used in conjunction with Class V restorations.     

Clinical performance of resin-modified glass ionomer cement restorations in primary teeth. A retrospective evaluation

BACKGROUND: The authors retrospectively evaluated the clinical performance of one resin-modified glass ionomer cement as a restorative material in Class I, Class II, Class III and Class V restorations in primary teeth. METHODS: A total of 306 patients who had received a total of 864 resin-modified glass ionomer restorations, which had been in their mouths for a minimum of three years, were included in this evaluation. The authors assessed the clinical observations recorded in patients' records and used bitewing radiographs to assess Class II restorations. RESULTS: The authors found an overall restoration success rate of 93.0 percent, with Class I restorations having a 92.6 percent success rate, Class II restorations having a 93.3 percent success rate, Class III restorations having a 100 percent success rate, and Class V restorations having a 98.0 percent success rate. CONCLUSIONS: The resin-modified glass ionomer cement functioned well as a Class I, Class II, Class III and Class V restorative material in primary teeth. CLINICAL IMPLICATIONS: Resin-modified glass ionomer restorative cement is a durable and reliable material to use for Class I, Class II, Class III and Class V restorations in primary teeth. Therefore, dentists have a proven alternative to silver amalgam and resin-based composite for primary tooth restoration.