Two-year clinical evaluation of direct and indirect composite restorations in posterior teeth

Clinical longevity of direct and indirect posterior resin composite restorations: An updated systematic review and meta-analysis

OBJECTIVES

To answer the PICO(S) question: Is there a difference in clinical longevity between direct and indirect resin composite restorations placed on permanent posterior teeth?

DATA

Randomized controlled clinical trials (RCTs) investigating direct and indirect resin composite restorations in posterior permanent teeth were considered.

SOURCES

Several electronic databases were searched, with no language or date restrictions. The revised Cochrane Collaboration's tool for assessing risk of bias (RoB-2) was used to analyze the studies; meta-analyses were run and the certainty of evidence was assessed by the GRADE tool. A subgroup meta-analysis was performed for resin composite restorations placed on posterior worn dentition.

STUDY SELECTION

Twenty-three articles were included in qualitative synthesis, while 8 studies were used for meta-analyses. According to the RoB-2 tool, 5 studies were ranked as "low risk", 7 had "some concerns", while 11 papers were rated as "high risk" of bias. There were no statistically significant differences in short-term (p = 0.27; RR=1.54, 95% CI [0.72, 3.33]), medium-term (p = 0.27; RR=1.87, 95% CI [0.61, 5.72]) and long-term longevity (p = 0.86; RR=0.95, 95% CI [0.57, 1.59]). The choice of restorative technique had no influence on short-term survival of resin composite restorations placed on worn dentition (p = 0.13; RR=0.46, 95% CI [0.17, 1.25]). The certainty of evidence was rated as "very low".

CONCLUSIONS

Direct and indirect resin composite restorations may show similar clinical longevity in posterior region, regardless of the observation period or substrate (wear-affected and non-affected dentition). The very low quality of evidence suggests that more long-term RCTs are needed to confirm our results.

Computer-aided design and computer-aided manufacturing indirect versus direct composite restorations: A randomized clinical trial

OBJECTIVE

This study compared the clinical performance of large indirect restorations (IRs) versus direct restorations (DRs) in posterior teeth.

METHODS

Thirty subjects received two class II restorations (n = 60), one fabricated from a precured composite block (Grandio Blocs, VOCO) for the indirect technique (IT) and the other with light-cured composite (GrandioSO, VOCO) for the direct technique (DT). For IT, the restoration was created using the computer-aided design and computer-aided manufacturer (CAD/CAM) system. For DT, the material was applied light-cured by using a layering technique. All restorations were evaluated by using the World Dental Federation criteria.

RESULTS

Twenty-three subjects attended the 2-year recall, and 46 restorations were evaluated. No significant differences were detected between the techniques for most parameters analyzed (p > 0.05). For "color match" at 7 days and 6 months, better results were observed for the DT. In relation to the overall scores, all restorations were esthetically acceptable after 2 years, while 93.3% of DT and 90% of IT showed acceptable function. For biological scores, 96.67% of DRs and 100% of IRs was acceptable after 24 months. Considering all properties, the success rates were 93.3% for DRs and 90% for IRs.

CONCLUSIONS

After 2 years, both restorations presented similar and good clinical behavior for all the properties analyzed.

CLINICAL SIGNIFICANCE

Light-cured direct posterior composite restorations may perform similarly to indirect composite restorations made with precured CAD/CAM composite blocks up to 2 years.

Pulp survival after composite resin restoration of caries lesions in adults

Minimal intervention is generally achieved by using direct composite resin (CR) restorations. However, deep caries lesions may lead to pulpal complications. This study evaluated the risk of endodontic complications after CR restoration in relation to depth of caries lesions. Data on 507 teeth from 316 adults treated with CR were analyzed. Caries depth was expressed as a percentage of the distance between the outer edge of the dental enamel and the pulp base on preoperative radiographs. The interval between CR restoration and follow-up root canal treatment was obtained from electronic treatment records for a period of 24 months. A Cox proportional hazards model was used to investigate the association between risk of endodontic complications and caries depth. Sixteen teeth (3.2%) required root canal treatment within 24 months. No root canal treatment was required after CR treatment for caries affecting <50% of the outer edge of enamel and pulp. As compared with CR treatment of caries lesions with a size of <80%, there was a significantly higher risk of root canal treatment for caries lesions with a size of 80% to 89% (hazard ratio, [95% CI]: 34.68 [4.23-284.11]) and ≥90% (92.01 [10.36-817.41], respectively).

Interfacial Fracture Toughness Comparison of Three Indirect Resin Composites to Dentin and Polyether Ether Ketone Polymer

OBJECTIVES

 Advances in laboratory composites and their high wear resistance and fracture toughness have resulted in their growing popularity and increasing use for dental restorations. This study sought to assess the fracture toughness of three indirect composites bonded to dental substrate and polyether ether ketone (PEEK) polymer.

MATERIALS AND METHODS

 This in vitro study was conducted on two groups of dental and polymer substrates. Each substrate was bonded to three indirect composite resins. Sixty blocks (3 × 3 × 12 mm) were made of sound bovine anterior teeth and PEEK polymer. Sixty blocks (3 × 3 × 12 mm) were fabricated of CRIOS (Coltene, Germany), high impact polymer composite (HIPC; Bredent, Germany), and GRADIA (Indirect; GC, Japan) composite resins. Composites were bonded to dentin using Panavia F 2.0 (Kuraray, Japan). For bonding to PEEK, Combo.lign (Bredent) and Visio.Link (Bredent) luting cements were used. In all samples, a single-edge notch was created by a no. 11 surgical blade at the interface. The samples were subjected to 3,500 thermal cycles, and their fracture toughness was measured in a universal testing machine (Zwick/Roell, Germany) by application of four-point flexural load.

STATISTICAL ANALYSIS

 Data were analyzed using one-way analysis of variance, Kruskal-Wallis.

RESULTS

 The fracture toughness of CRIOS-PEEK interface was significantly higher than HIPC-PEEK. The fracture toughness of GRADIA-PEEK was not significantly different from that of HIPC and CRIOS. The fracture toughness of GRADIA-dentin was significantly higher than HIPC-dentin.

CONCLUSION

 Considering the limitations of this study, GRADIA has the highest bond strength to dentin, while CRIOS shows the highest bond strength to PEEK.

Development of an Innovative Urease-Aided Self-Healing Dental Composite

Dental restorative materials suffer from major drawbacks, namely fracture and shrinkage, which result in failure and require restoration and replacement. There are different methods to address these issues, such as increasing the filler load or changing the resin matrix of the composite. In the present work, we introduce a new viable process to heal the generated cracks with the aid of urease enzyme. In this system, urease breaks down the salivary urea which later binds with calcium to form calcium carbonate (CaCO3). The formation of insoluble CaCO3 fills any resultant fracture or shrinkage from the dental composure hardening step. The healing process and the formation of CaCO3 within dental composites were successfully confirmed by optical microscope, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDS) methods. This research demonstrates a new protocol to increase the service life of dental restoration composites in the near future.

Two-year performance of CAD/CAM fabricated resin composite inlay restorations: A randomized controlled clinical trial

OBJECTIVE

The aim of this study was to evaluate the 2-year clinical performance of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite inlay restorations in comparison with direct resin composite restorations.

MATERIALS AND METHODS

In 44 patients, 120 class II (mesio-occlusal/disto-occlusal) cavities were randomly assigned into two groups; CAD/CAM resin composite inlay group (Lava Ultimate), direct resin composite group (Clearfil Majesty Posterior). Clinical evaluations were performed after 1 week, 6 months, 1 year, and 2 years according to the FDI criteria. The data were analyzed using Friedman's ANOVA and Mann-Whitney U tests (α = .05).

RESULTS

In 41 patients, 114 restorations were evaluated at the second year (recall rate 93.2%). All restorations were ideal or clinically acceptable. At the first year, considering all criteria, there were no statistically significant differences between the groups. However, there was a significant difference in terms of surface luster at second year, in favor of inlay restorations (P = .015). The marginal staining of resin composites increased after 2 years (P = .046), but there was no significant difference between the groups.

CONCLUSIONS

Except the surface luster, 2-year clinical performance of CAD/CAM resin composite inlay restorations was found similar to direct resin composite restorations according to FDI criteria CLINICAL SIGNIFICANCE: The clinical performance of CAD/CAM resin composite inlays was acceptable in class II cavities subsequent to 2-year evaluation.

Influence of adhesive-composite application modalities on their bonding to tooth structure and resistance of the performed restorations to failure

Background/purpose

The longevity of bonded composite restorations could be affected by the utilized adhesive-composite application techniques. This in vitro study aimed to evaluate the influence of adhesive-composite application modalities on their bonding values to tooth structure and on the failure resistance of the performed restorations on loading.

Materials and methods

Resin composite studs, 2 mm in diameter and 4 mm high, were bonded in 2 groups to flattened enamel and dentin surfaces of 80 extracted premolars using pre-cured (PC) and co-cured (CC) self-etch resin adhesive. Studs in each group were built-up in 4 subgroups using either multiple increments of nano-filled composite (IF, control) or single increment of preheated nano-filled (PH), bulk-fill (BF) and sonic-activated bulk-fill composites (SF). Another 80 premolars with standard class II cavities were also restored using the same adhesive-composite application modalities. All specimens were then stressed on a universal testing machine to assess the composite-tooth shear bond strength and the resistance of the performed restorations to failure. The modes of specimens’ failure were also assessed following each test.

Results

The PC adhesive provided higher bond strength to dentin (p < 0.05) and comparable bond strength to enamel in comparison to the CC one (p>0.05%). Both PH and BF composites showed lower bond strength to dentin in presence of PC adhesive (p < 0.05). Comparable bond strengths were noticed for PH, BF and SF composites to dentin in presence of CC adhesive (p > 0.05). PH and SF restorations presented the highest resistance to failure (p < 0.05).

Conclusion

Both incrementally and bulky-inserted composites offer clinically acceptable bond strength in presence of pre-cured resin adhesive. Both Preheated and sonic-activated composite restorations offer the highest resistance to failure on loading. The preheating procedure renders regular composite material suitable for bulk-fill applications.

Complications and survival rates of inlays and onlays vs complete coverage restorations: A systematic review and analysis of studies

OBJECTIVE

The aim of this study was to identify if different types of indirect restorations used for single teeth had different biological and technical complications, as well as survival rates.

METHOD

An electronic search was performed in various electronic databases to identify articles, published between 1980 and 2017. The search terms were categorised into 4 groups: inlay, onlay, inlay/onlay and crown. Manual searches of published full-text articles and related reviews were also performed.

RESULTS

A total number of 2849 papers were retrieved initially. After a detailed assessment for eligibility, 9 studies were selected for inclusion. The heterogeneity of the studies did allow neither a meta-analysis nor any meaningful comparison between types of restorations or materials. Only some pooling was performed for representative reasons. The mean survival rate of inlays was 90.89%, while for onlays and crowns it was 93.50% and 95.38%, respectively. For the fourth study group, consisting of both inlays and onlays, the survival rate was found to be 99.43%. Statistical analysis demonstrated caries to be the main biological complication for all types of restorations, followed by a root and/or tooth fracture incidence (11.34%) and endodontic incidence. Ceramic fractures represented the most common technical complication, followed by loss of retention and porcelain chipping.

CONCLUSION

The 5-year survival rate for crowns and inlays/onlays is very high, exceeding 90%. An association between the kind of complications and different types of restorations could not be established. Nevertheless, a relatively high failure rate due to caries and ceramic fractures was noted.

Wear Resistance of Bulk-fill Composite Resin Restorative Materials Polymerized under different Curing Intensities

INTRODUCTION

The aim of this study was to assess the wear resistance of four bulk-fill composite resin restorative materials cured using high- and low-intensity lights.

MATERIALS AND METHODS

Twenty-four samples were prepared from each composite resin material (Tetric N-Ceram, SonicFill, Smart Dentin Replacement, Filtek Bulk-Fill) resulting in a total of 96 samples; they were placed into a mold in a single increment. All of the 96 samples were cured using the Bluephase N light curing unit for 20 seconds. Half of the total specimens (n = 48) were light cured using high-intensity output (1,200 mW/cm²), while the remaining half (n = 48) were light cured using low-intensity output (650 mW/cm²). Wear was analyzed by a three-dimensional (3D) noncontact optical profilometer (Contour GT-I, Bruker, Germany). Mean and standard deviation (SD) of surface loss (depth) after 120,000 cycles for each test material was calculated and analyzed using one-way analysis of variance (ANOVA) with a significance level at p < 0.05.

RESULTS

The least mean surface loss was observed for SonicFill (186.52 urn) cured using low-intensity light. No significant difference in the mean surface loss was observed when comparing the four tested materials with each other without taking the curing light intensity into consideration (p = 0.352). A significant difference in the mean surface loss was observed between SonicFill cured using high-intensity light compared with that cured using low-intensity light (p < 0.001).

CONCLUSION

A higher curing light intensity (1,200 mW/cm²) had no positive influence on the wear resistance of the four bulk-fill composite resin restorative materials tested compared with lower curing light intensity (650 mW/cm²). Furthermore, SonicFill cured using low-intensity light was the most wear-resistant material tested, whereas Tetric N-Ceram cured using high-intensity light was the least wear resistant.

CLINICAL SIGNIFICANCE

The wear resistance was better with the newly introduced bulk-fill composite resins under low-intensity light curing.

Longevity of direct and indirect resin composite restorations in permanent posterior teeth: A systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analysis was to assess the differences in clinical performance in direct and indirect resin composite restorations in permanent posterior teeth.

SOURCES

PubMed, the Cochrane Library, Web of Science, Scopus, LILACS, BBO, ClinicalTrials.gov and SiGLE were searched without restrictions.

STUDY SELECTION

We included randomized clinical trials (RCTs) that compared the clinical performance of direct and indirect resin composite restorations in Class I and Class II cavities in permanent teeth, with at least two years of follow-up. The risk of bias tool suggested by Cochrane Collaboration was used for quality assessment.

DATA

After duplicate removal, 912 studies were identified. Twenty fulfilled the inclusion criteria after the abstract screening. Two articles were added after a hand search of the reference list of included studies. After examination, nine RCTs were included in the qualitative analysis and five were considered to have a 'low' risk of bias. The overall risk difference in longevity between direct and indirect resin composite restorations in permanent posterior teeth (p>0.05) at five-year follow-up was 1.494 [0.893-2.500], and regardless of the type of tooth restored, that of molar and premolars was 0.716 [0.177-2.888] at three-year follow-up.

CONCLUSIONS

Based on the findings, there was no difference in longevity of direct and indirect resin composite restorations regardless of the type of material and the restored tooth.

CLINICAL SIGNIFICANCE

Contemporary dentistry is based on minimally invasive restorations. Any indication of a less conservative technique must have unquestionable advantages. In vitro and in vivo studies reveal contradictory evidence of the clinical performance of direct and indirect resin composite restorations in posterior teeth. Thus this study clarified this doubt.

Indirect composite restorations luted with two different procedures: A ten years follow up clinical trial

Objectives: The aim of this clinical trial was to evaluate posterior indirect composite resin restoration ten years after placement luted with two different procedures. Study Design: In 23 patients 22 inlays/onlays (Group A) were luted using a dual-cured resin composite cement and 26 inlays/onlays (Group B) were luted using a light cured resin composite for a total of 48 Class I and Class II indirect composite resin inlays and onlays. The restorations were evaluated at 2 time points: 1) one week after placement (baseline evaluation) and 2) ten years after placement using the modified USPHS criteria. The Mann-Whitney and the Wilcoxon tests were used to examine the difference between the results of the baseline and 10 years evaluation for each criteria. Results: Numerical but not statistically significant differences were noted on any of the recorded clinical parameters (p>0.05) between the inlay/onlays of Group A and Group B. 91% and 94 % of Group A and B respectively were rated as clinically acceptable in all the evaluated criteria ten years after clinical function. Conclusions: Within the limits of the study the results showed after ten years of function a comparable clinical performance of indirect composite resin inlays/onlays placed with a light cure or dual cure luting procedures.

Key words:Light curing composite, dual curing composite, indirect composite restoration, inlays/onlays, clinical trial.

Comparative evaluation of effects of bleaching on color stability and marginal adaptation of discolored direct and indirect composite laminate veneers under in vivo conditions

Statement of Problem:

Change in color and loss of marginal adaptation of tooth colored restorative materials is not acceptable. Bleaching is commonly used for treating discolored teeth. However, the literature is scanty regarding its effect on color and marginal adaptation of direct and indirect composite laminate veneers (CLVs) under in vivo conditions.

Purpose:

Purpose of the study was to determine the effect of bleaching on color change and marginal adaptation of direct and indirect CLVs over a period of time when exposed to the oral environment.

Materials and Methods:

For this purpose, a total of 14 subjects irrespective of age and sex indicated for CLV restorations on maxillary anterior teeth were selected following the inclusion and exclusion criteria. For each subject, indirect CLVs were fabricated and looted in the first quadrant (Group 1) and direct CLV's (Group 2), were given in the second quadrant. Color change was assessed clinically using intra-oral digital spectrophotometer and marginal adaptation was assessed on epoxy resin replica of the tooth-restoration interface under scanning electron microscope. After 6 months, the subjects underwent a home bleaching regimen for 14 days using 10% carbamide peroxide. The assessment of color change and marginal adaptation was done at 6 months after veneering (0–180 days), immediately after the bleaching regimen (0–194 days) and 3 months after the bleaching regimen (0–284 days).

Results:

The difference in median color change (ΔE) between the groups was tested using Wilcoxon rank sum test while the median color change with time within the groups was tested using Wilcoxon signed rank test. The difference in the rates of marginal adaptation was tested between the groups using Chi-square/Fisher's exact test.

Bleaching led to statistically significant color change at cervical (CE), middle and incisal (IE) regions when direct and indirect composites were compared (P < 0.05). During intra-group comparison, direct CLV's showed significant color change at CE and IE regions when ΔE was compared at 180 days and 284 days (CE 10 vs. CE 30, P = 0.008, IE 10 vs. IE 30, P = 0.003). No significant differences were found when within group comparison was made for indirect laminates. Intergroup comparison between the groups showed significant difference in marginal adaptation at CE margin at all.time points (at baseline, P = 0.005; at 180 days, P = 0.007; 194 days, P = 0.025; at 284 days, P = 0.067).

Conclusion:

After bleaching, indirect CLVs performed better in terms of color stability whereas direct CLVs performed better in terms of marginal adaptation.

Clinical Significance:

Indirect composites should be preferred to direct composites as veneering materials as they have better color stability. Special attention should be given to their marginal adaptation especially in the CE region. Bleaching should be avoided in patients with composite restorations in the mouth.

A Five-Year Clinical Evaluation of Direct Nanofilled and Indirect Composite Resin Restorations in Posterior Teeth

Aim:

To assess the clinical efficacy of posterior composite resin restorations placed directly and indirectly in posterior teeth after five years.

Materials and Methods:

A total of 108 cavities in 54 patients were restored with three direct composite resins (Filtek SupremeXT [FSXT], Tetric Evo Ceram [TEC], AELITE Aesthetic [AA]) and two indirect composite resins (Estenia [E] and Tescera ATL [TATL]). All restorations were evaluated by two examiners using the United States Public Health Service criteria at baseline and five years after placement. Statistical analysis was completed with Fisher exact and McNemar χ2 tests.

Results:

At baseline, 4% (five) of the restored teeth presented postoperative sensitivity; however, only one of them (a member of the E group) required canal treatment and replacement after two years. At the five-year evaluation, all restorations were retained, with Alpha ratings at 100%. Only one tooth (in the TEC group) required replacement after three years due to secondary caries. Color match, surface texture, and marginal integrity were predominantly scored as Alpha after five years for all groups. After that time, marginal discoloration was scored as Alpha in 64% of AE restorations, 70% of TATL restorations, 73% of E restorations, and 87% of FSXT restorations. There were no Charlie scores recorded for any of the restorative systems.

Conclusions:

Under controlled clinical conditions, indirect composite resin inlays and direct composite resin restorations exhibited an annual failure rate of 2.5% and 1.6%, respectively, after five years. Therefore, the investigated materials showed acceptable clinical performance, and no significant differences were found among them.

Effect of proximal box elevation with resin composite on marginal quality of resin composite inlays in vitro

OBJECTIVES

To evaluate marginal quality and resin-resin transition of lab made resin composite inlays in deep proximal cavities with and without 3 mm proximal box elevation (PBE) using resin composites before and after thermo-mechanical loading (TML).

METHODS

MOD cavities with one proximal box beneath the cementoenamel junction were prepared in 40 extracted human third molars. Proximal boxes ending in dentine were elevated 3 mm with different resin composites (G-Cem, Maxcem Elite as self-adhesive resin cements and Clearfil Majesty Posterior as restorative resin composite in one or three layers bonded with AdheSE), or left untreated. Clearfil Majesty Posterior inlays were luted with Syntac and Variolink II (n = 8). Marginal quality as well as the PBE-composite inlay interface was analyzed under an SEM using epoxy resin replicas before and after thermomechanical loading (100,000 × 50 N and 2500 thermocylces between +5 °C and +55 °C).

RESULTS

Bonding resin composite inlays directly to dentine showed similar amounts of gap-free margins in dentine compared to PBE applied in three consecutive layers (p > 0.05). The groups with self-adhesive resin cements for PBE exhibited significantly more gaps in dentine (p < 0.05).

SIGNIFICANCES

With layered resin composite, PBE is effective in indirect resin composite bonding to deep proximal boxes. Self-adhesive resin cements are not suitable for this indication.

Evaluation of Light Intensity Output of QTH and LED Curing Devices in Various Governmental Health Institutions

Evaluating the intensity of a light curing unit regularly prior to the application of tooth-colored restorative materials is essential to assure the quality of restorative procedures.

Clinical evaluation of indirect composite restorations at baseline and 36 months after placement

This study determined the differences in clinical performance between materials for indirect composite restorations based on Ormocer (Admira) and nano-hybrid resin composite (Grandio), both at baseline and 36 months after placement. Modified USPHS criteria were used to analyze the degree of quality. Marginal integrity was assessed 36 months after placement, whereupon, the restorations fabricated from Grandio achieved an Alpha 1 score of 70.7% and an Alpha 2 score of 29.3%. The Wilcoxon test revealed a statistically significant difference in the evaluation of marginal integrity (p = 0.003), anatomic form of the marginal step (p = 0.025) and discoloration of the margins (p = 0.014) at baseline and after 36 months. For Admira, the Wilcoxon test showed statistically significant differences in the evaluation of surface texture (p = 0.025), anatomic form of the complete surface (p = 0.034), anatomic form of the marginal step (p = 0.008), marginal integrity (p = 0.002) and discoloration of the margins (p = 0.008) at baseline and after 36 months. According to the number of restorations awarded the Alpha 1 score (excellent), the overall success rates for marginal integrity were 70.7% for Grandio and 71.8% for Admira; both were evaluated 36 months after placement. The results have shown that the indirect restorations were acceptable after 36 months, which indicates a 100% success rate. Over 36 months, no statistically significant differences were noted between the two materials. Indirect resin composite restorations represent a good therapy choice for severely damaged teeth.

One-year clinical evaluation of direct nanofilled and indirect composite restorations in posterior teeth

The aim of this study was to assess the clinical performance of three direct composite resins and two indirect inlay systems in posterior teeth using the modified USPHS criteria. A total of 100 restorations were placed in the molars of 54 patients by one operator. All restorations were directly evaluated by two examiners at baseline, 6 months, and 12 months. Statistical analysis was conducted using McNemar chi-square test at a significance level of 5% (p<0.05). Recall rate was 100% at 6 and 12 months, and all the restorations evaluated (i.e., 100%) received Alpha rating for the criteria of retention and gingival adaptation. At 12 months for the surface texture criterion, 80% of Filtek Supreme XT received Alpha rating while it was 95% for Tetric EvoCeram and AELITE Aesthetic. For marginal discoloration, 85% of Tescera ATL and Filtek Supreme XT received Alpha rating while it was 95% for Tetric EvoCeram and AELITE Aesthetic. Further, none of the restorative systems received a Charlie rating for any of the criteria at all evaluation periods. In summary, all the restorations demonstrated clinically satisfactory performance with no significant differences detected among them.

Degradation, fatigue, and failure of resin dental composite materials

The intent of this article is to review the numerous factors that affect the mechanical properties of particle- or fiber-filler-containing indirect dental resin composite materials. The focus will be on the effects of degradation due to aging in different media, mainly water and water and ethanol, cyclic loading, and mixed-mode loading on flexure strength and fracture toughness. Several selected papers will be examined in detail with respect to mixed and cyclic loading, and 3D tomography with multi-axial compression specimens. The main cause of failure, for most dental resin composites, is the breakdown of the resin matrix and/or the interface between the filler and the resin matrix. In clinical studies, it appears that failure in the first 5 years is a restoration issue (technique or material selection); after that time period, failure most often results from secondary decay.

An overview of treatment considerations for esthetic restorations: a review of the literature

Controversy persists regarding the treatment planning criteria for esthetic restorations. This article reviews the literature regarding the biocompatibility, marginal adaptation, color matching, patient selection, technique sensitivity, and mode and rate of failure of tooth-colored restorations. A Medline search was completed for the period from 1986 to 2006, along with a manual search, to identify pertinent English peer-reviewed articles and textbooks. The key words used were amalgam, posterior composite resin, ceramic inlays/onlays, CEREC, porcelain laminate veneers, all-ceramic crowns, and all-ceramic fixed partial dentures.

Five-year clinical performance of posterior resin composite restorations placed by dental students

OBJECTIVES

To investigate the survival over a five-year period of posterior resin composite restorations placed by students.

METHODS

Class I and II resin composite restorations placed by second-fourth year dental students were evaluated. Patients attended the dental school every 6 months for a regular check-up during which all restorations were checked on their clinical acceptability. In case of replacement or repair of a restoration, this was registered in the patient's record. From each record the survival time and reasons for failure of resin composite restorations were gathered.

RESULTS

Seven-hundred three posterior resin composite restorations in 382 patients (49% female and 51% male, age 22-78) were evaluated. At 5 years 560 of the 703 restorations were still considered to be "clinically acceptable". Forty-nine restorations were considered as "functionally present", of which 44 were restored with a crown and four had received a new restoration adjacent to the existing restoration without its removal. Ninety-four restorations had failed. The main reasons for failure were restoration fracture, caries, endodontic treatment, defective margin and lack of proximal contact. The survival rate of the restorations was 87% at 5 years, resulting in an annual failure rate of 2.8%.

CONCLUSIONS

Dental students are able to place resin composite restorations in posterior teeth with an acceptable mean annual failure rate.

Evaluation of performance of dental providers on posterior restorations: does experience matter? A data envelopment analysis (DEA) approach

The purpose of this study is to discern what factors affect the longevity of amalgam and of composite restorations by dentists who perform posterior restorations. Data are obtained from the Washington Dental Service and contain 1.5 million patient encounters representing visits to 23,000 providers from January 1993 through 31 December 1999. Analysis of provider performance is estimated through Data Envelopment Analysis. The principal finding is that the most efficient dentists produce posterior restorations that survive almost 5 months (4.6 months) longer than those by inefficient providers (chi2 = 18.98, p < 0.0001). The findings suggest that there is no difference in restoration longevity between amalgam and composite restorations when the restoration is performed by efficient provider.

Ceramic Inlays and Onlays: Clinical Procedures for Predictable Results

The use of ceramics as restorative materials has increased substantially in the past two decades. This trend can be attributed to the greater interest of patients and dentists in this esthetic and long-lasting material, and to the ability to effectively bond metal-free ceramic restorations to tooth structure using acid-etch techniques and adhesive cements. The purpose of this article is to review the pertinent literature on ceramic systems, direct internal buildup materials, and adhesive cements. Current clinical procedures for the planning, preparation, impression, and bonding of ceramic inlays and onlays are also briefly reviewed. A representative clinical case is presented, illustrating the technique.

CLINICAL SIGNIFICANCE

When posterior teeth are weakened owing to the need for wide cavity preparations, the success of direct resin-based composites is compromised. In these clinical situations, ceramic inlays/onlays can be used to achieve esthetic, durable, and biologically compatible posterior restorations.

Longevity of direct resin composite restorations in posterior teeth

This review is a survey of prospective studies on the clinical performance of posterior resin composites published between 1996 and 2002. Material, patient- and operator-specific data, observation periods, isolation methods of the operative field, and failure rates are detailed in tables. The data were evaluated statistically in order to assess the role of materials (filler size, bonding system, base materials [e.g. glass ionomer cements], and lining materials), study design, and personnel on failure rates. The primary reasons for composite failure were secondary caries, restoration fracture, and marginal defects. The influence of different commercial material brands on failure rates was not evaluated due to the great variety of test substances and the lack of material-specific documentation. Effects of the isolation method of the operative field (rubber dam or cotton rolls) and the professional status of operators (university or general dentist) on composite failure rates were not found to be significant. Observation periods varied from 1 to 17 years, and failure rates ranged between 0% and 45%. A linear correlation between failure rate and observation period was found (P<0.0001). Thirteen of 24 studies were terminated after 3 years, while seven studies continued for more than 10 years, indicating that favourable results for composite materials are frequently based on short-term results, despite higher dropout rates in longer studies. To determine accurately the risk for patients, long-term, randomised, controlled clinical trials of treatment outcomes with composites used in posterior teeth are clearly needed.

Marginal deterioration as a predictor of failure of a posterior composite

The purpose of the present study was to undertake a retrospective analysis of the findings of a multicentre clinical trial to test the hypothesis that marginal deterioration and cavomarginal discoloration may be a predictor of the failure of posterior composite restorations. Longitudinal 5-yr data from the multicentre trial of Occlusin were analysed (modified USPHS criteria data were available in respect of 1018 of the 1242 restorations included in the study). The 5-yr failure rate was calculated using three different methods. The various failure rates (maximum 18.8%) and the data pertaining to marginal deterioration and cavomarginal discoloration were then compared and contrasted by means of chi2 test. The analysis revealed that restorations with marginal deterioration at 3 yr were 5.3 times more likely to have failed by 5 yr than restorations with A (Alfa) rated marginal adaptation at 3 yr. Similarly restorations with cavomarginal discoloration at 3 yr were found to be 3.8 times more likely to have failed at 5 yr than restorations with no cavomarginal discoloration at 3 yr. Moreover, restorations with both marginal deterioration and cavomarginal discoloration at 3 yr failed 8.7 times more frequently than restorations with sound margin at 3 yr. It is concluded that clinical investigations of present-day materials for posterior composite should seek to determine if marginal deterioration and cavomarginal discoloration is an important predictor of the failure of posterior composites, especially when marginal deterioration and cavomarginal discoloration occur simultaneously.

Fracture toughness of packable and conventional composite materials

STATEMENT OF PROBLEM

The introduction of packable composite has expanded the choices of materials for the restoration of posterior teeth. Few independent studies are available on the fracture toughness (K(IC)) of the presently available packable composites compared with more conventional composite alternatives.

PURPOSE

This investigation evaluated the relative fracture toughness of 3 packable composites, 2 conventional composites, and 1 laboratory-processed composite.

MATERIALS AND METHODS

Six composite materials were tested in this study. These included: 3 packable composites (Alert, SureFil and Solitaire), 2 conventional composites (Herculite and Heliomolar), and 1 laboratory-processed composite (Belleglass). K(IC) was determined by preparing 8 mini-compact test specimens (8.2 mm diameter x 2 mm thickness) for each composite in a polytetrafluoroethylene split-mold with introduced precracks created with a razor blade. Specimens were stored in distilled water at 37 degrees +/- 2 degrees C for 7 days. Testing was performed on a universal testing machine at a displacement rate of 0.5 mm/min until fracture. Analysis of variance (P<.0001) and Ryan-Einot-Gabriel-Welsch multiple range tests (P<.05) were performed on all data.

RESULTS

The mean fracture toughness of Alert (1.57 Mpa x m(1/2)) was significantly greater than any of the other composites tested. Solitaire, a packable composite, exhibited a mean fracture toughness (0.67 MPa x m(1/2)) that was significantly lower than any of the other materials tested. No significant difference was noted between Belleglass (1.27 MPa x m(1/2)), SureFil (1.25 MPa x m(1/2)) and Herculite (1.16 MPa x m(1/2)).

CONCLUSION

Within the limitations of this study, the glass fiber-reinforced packable composite exhibited improved fracture toughness when compared with the other composite materials tested.

The double-inlay technique: a new concept and improvement in design

Gold and ceramic have long been used in prosthetic dentistry. In the posterior region, it is possible to use both materials with the double-inlay technique to add the strength of metal to the esthetics of ceramic. The problem, however, remains the volume of tooth reduction required to avoid ceramic fracture. This article describes a modification of the double-inlay technique that makes use of a pin system. This modified technique permits good retention while avoiding excessive tooth reduction.

The suitability of packable resin-based composites for posterior restorations

BACKGROUND

Packable composites, promoted for the restoration of stress-bearing posterior teeth, have captured clinicians' interest.

METHODS

The authors tested three packable composites (Alert, Jeneric/Pentron; Solitaire, Heraeus Kulzer, Wehrheim, Germany; SureFil, Dentsply De Trey, Konstanz, Germany); a new packable organically modified ceramic, or ormocer (Definite, Degussa AG, Hanau, Germany); a hybrid composite (Tetric Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) and an ion-releasing composite (Ariston pHc, Ivoclar Vivadent, Schaan, Liechtenstein). They determined modulus of elasticity according to EN 24049:1993 of the European Committee for Standardization. They measured Vickers hardness using a 200-gram load for 40 seconds. To determine the materials' depth of cure, they used both a scraping method (International Standards Organization standard CD 4049:1997) and a hardness profiling method.

RESULTS

The authors calculated means and standard deviations from 10 replications of each test and used one-way analysis of variance and post hoc Tukey tests (alpha = .05). The materials had significant differences (P < .001) in all characteristics. Solitaire had the significantly lowest elastic modulus and microhardness; Alert had the highest values for these characteristics. Ariston pHc exhibited the significantly lowest depth of cure. There was a significant correlation between the two methods of measuring depth of cure (r2 = 0.9945; P = .021).

CONCLUSIONS

The material group of packable composites is rather inhomogeneous in terms of mechanical and physical data. Our data suggest that bulk curing of packable composites in deep cavities still is not recommendable.

CLINICAL IMPLICATIONS

The clinician needs to select packable composites carefully, as it seems that not all of these materials quality for stress-loaded posterior restorations.

Three-year clinical evaluation of direct and indirect composite restorations in posterior teeth

STATEMENT OF THE PROBLEM

Objective long-term clinical data are necessary to assess the performance of modern posterior composites as direct and indirect restorations.

PURPOSE

This prospective, long-term clinical trial evaluated direct and indirect composite restorations for clinical acceptability as posterior restoratives in single or multisurface cavities and provided a survey on the 3-year results.

MATERIAL AND METHODS

Under the supervision of an experienced dentist, 9 dental students placed 88 composite restorations (Tetric, blend-a-lux, Pertac-Hybrid Unifil), 43 direct composite restorations, and 45 indirect inlays. Clinical evaluation was performed at baseline and in yearly intervals after placement by 2 other experienced dentists, using modified USPHS criteria. A third follow-up of 60 restorations took place within 33 to 36 months after placement.

RESULTS

A total of 93% of indirect and 87% of direct restorations were assessed to be clinically excellent or acceptable. During the third year, 1 direct restoration in a molar failed because of margin opening. Indirect inlays exhibited a significantly better anatomic form of the surface than direct composite restorations. Premolars revealed a significantly better marginal integrity and anatomic form of the surface than molars. Restorations in molars exhibited a significantly higher failure rate compared with premolars.

CONCLUSION

Posterior composite restorations provided a satisfactory clinical performance over a 3-year period, even if placed by relatively inexperienced but supervised students.