Two-year evaluation of a nano-hybrid and a bulk-fill resin composite: a randomized, double-blind split-mouth clinical study

OBJECTIVES

The aim of this study was to compare the 2-year clinical performance of a bulk-fill composite resin and a nano-hybrid-filled composite resin in 6-12-year-old children in a split-mouth design.

MATERIALS AND METHODS

This randomized, split-mouth, and double-blind study was conducted on 89 patients aged 6-12 years with caries on bilateral mandibular first molars. In a split-mouth design, restorations of mandibular permanent molars were completed with nano-hybrid organically modified ceramic (ORMOCER)-based bulk-fill composite resin Admira Fusion x-tra (Voco GmbH, Cuxhaven, Germany) and nano-hybrid composite Grandio (Voco, Cuxhaven, Germany). Futurabond U single dose (Voco, Cuxhaven, Germany) was used with selective enamel etching. The clinical success of the restorations was evaluated using USPHS and FDI criteria at 6, 12, and 24-month follow-up controls.

RESULTS

In the 2-year follow-up, all restorations were clinically acceptable. Grandio was significantly worse than Admira Fusion x-tra in terms of surface luster and superficial change (p < 0.05). Surface staining and color match scores increased in Admira Fusion x-tra compared with Grandio significantly (p < 0.05).

CONCLUSIONS

Although both materials showed acceptable clinical performance over 2 years, a significant difference was observed between the surface luster, surface staining, marginal adaptation, and staining of the nano-hybrid composite placed with the incremental technique and the bulk-fill ORMOCER-based composite resin.

CLINICAL RELEVANCE

As an alternative to nano-hybrid composite resins, using bulk-fill restorative materials, which can be indicated in the proper case, may contribute to shortening treatment procedures and increasing patient and physician comfort, leading to clinical success.

3-year randomized clinical trial to evaluate the performance of posterior composite restorations lined with ion-releasing materials

To evaluate the impact of using ion-releasing liners on the 3-year clinical performance of posterior resin composite restorations after selective caries excavation with polymer burs. 20 patients were enrolled in this trial. Each patient had two deep carious lesions, one on each side of the mouth. After selective caries removal using polymer bur (PolyBur P1, Komet, Brasseler GmbH Co. KG, Lemgo, Germany), cavities were lined with bioactive ionic resin composite (Activa Bioactive Base/Liner, Pulpdent, Watertown, MA, USA) or resin-modified glass ionomer liner (Riva Light Cure, SDI, Bayswater, Victoria, Australia). All cavities were then restored with nanofilled resin composite (Filtek Z350XT, 3M Oral Care, St. Paul, MN, USA). All the tested materials were placed according to the manufacturers' instructions. Clinical evaluation was accomplished using World Dental Federation (FDI) criteria at baseline and after 6 months, 1, 2, and 3 years. Data were analyzed using Mann-whitney U and Friedman tests (p < 0.05). The success rates were 100% for all resin composite restorations either lined with ion-releasing resin composite or resin-modified glass ionomer liner. Mann-whitney U test revealed that there were no statistically significant differences between both ion-releasing lining material groups for all criteria during the follow-up periods (p > 0.05). Resin composite restorations showed acceptable clinical performance over 3 years either lined with bioactive ionic or resin-modified glass ionomer liners after selective caries excavation preserving pulp vitality. After the 3-year follow-up period, Activa Bioactive and Riva Light Cure liners were clinically effective and they exhibited with the overlying composite restorations successful clinical performance.Trial registration number: NCT05470959. Date of registration: 22/7/2022. Retrospectively registered.

Evaluation of the proximal contact tightness in class II resin composite restorations using different contact forming instruments: a 1-year randomized controlled clinical trial

BACKGROUND

Proper proximal contact in direct composite restorations is crucial for periodontal health. Over a one-year period, this study was conducted to assess successive biological changes in proximal contact tightness PCT in class II direct composite restorations and the adjacent teeth by applying sectional matrix system along with different contact forming instruments.

METHODS

72 direct compound class II composite restorations were performed in patients aged 18-40 years and divided into 4 groups: Group I (n = 18): proximal contact was restored with Palodent plus sectional matrix system, Group II (n = 18): Trimax as contact forming instrument, Group III (n = 18): Perform as contact forming instrument and Group IV (n = 18): Contact pro as contact forming instrument. All contact forming instruments were used along with Palodent plus matrix system. PCT was measured using a digital force gauge before (T0), immediate post operative (T1) and at 3 (T2), 6 (T3), 9 (T4), and 12 months (T5) after restorative treatment. Using One-Way ANOVA, Tukey's post hoc test, and Bonferroni correction, PCT values were compared between groups before and after the intervention restoration. Meanwhile, for comparisons within groups, a paired t-test was conducted (p ≤ 0.05).

RESULTS

Contact forming instruments combined with Palodent plus sectional matrix system achieved better PCT. Trimax led to a statistically considerable tighter proximal contacts than the other groups (p < 0.05). No statistically significant difference was found in PCT between Contact pro-2, Perform and Palodent plus sectional matrix system. By means of multivariate analysis, the PCT between both T0 and T1 were increased (p < 0.001) and then it decreased till T5.

CONCLUSIONS

The use of transparent contact forming instruments achieved greater PCT compared to Palodent sectional matrix system alone that gradually decreased throughout 12 months and reached the PCT between the natural teeth. Using Trimax system provided the tightest proximal contacts. Additionally, digital force gauge was confirmed as an inclusive and accurate method to quantify PCT.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05749640: 24/5/2022.

The clinical performance of bulk-fill versus the incremental layered application of direct resin composite restorations: a systematic review

OBJECTIVES

To systematically review the scientific evidence comparing the clinical effectiveness of bulk-fill versus incrementally layered conventional resin composites and to evaluate if one method offers clear merits with specific clinical outcomes.

MATERIALS AND METHODS

Using relevant mesh terms and pre-established eligibility criteria in PubMed, Embase, Scopus and Web of Science, a thorough scientific search was conducted with an end-date of 30.04.2023. Randomized controlled clinical trials that involved the direct comparison of Class I and Class II resin composite restorations applied using incremental layering techniques versus bulk-filled in permanent teeth with an observation period of at least six months were considered. To evaluate the bias risk of the finalized records, a revised version of the Cochrane risk-of-bias tool for randomized trials was implemented.

RESULTS

Out of the 1445 records determined, 18 eligible reports were chosen for qualitative analysis. Data obtained was categorized as per, the cavity design, the intervention, the comparator(s), the methods of success/failure assessment, the outcomes, and follow-up. Two studies demonstrated an overall low-risk of bias, fourteen studies raised some concerns, and two studies exhibited high-risk.

CONCLUSION

Bulk filled resin composite restorations demonstrated clinical outcomes similar to those of incrementally layered resin composite restorations within a review interval of 6 months to 10 years.

Clinical evaluation of bulk-fill and universal nanocomposites in class II cavities: Five-year results of a randomized clinical split-mouth trial

AIM

Evaluating the clinical survival and quality parameters of class-II restorations using 3M™ Filtek^TM Bulk Fill Posterior Restorative compared to 3M™ Filtek^TM Supreme XTE Universal Restorative over a period of five years.

MATERIALS AND METHODS

A longitudinal, randomized, prospective split-mouth study with 60 patients (29 female, 31 male; mean age 44 y; range 20-77 y) and a total of 120 load-bearing class II restorations (TEST: n=60 Filtek Bulk Fill Posterior Restorative; CONTROL: n=60 Filtek Supreme XTE Universal Restorative) was conducted. Clinical evaluation was performed by blinded evaluators according to FDI criteria. Kaplan-Meier method was used for survival analysis and an intergroup comparison (Mann-Whitney-U-Test) was carried out. A basic significance level of 0.05 was corrected by the Bonferroni method to account for multiple testing (significance after correction: p<0.00067).

RESULTS

The mean overall survival of restorations was 92% after 56.98±1.51 months in the TEST group (95 CI= 54.02;59.94) and 92% after 57.25±1.46 months (95 CI= 54.39; 60.12) in the CONTROL group (log-rank p=0.995). In total, four failures occurred in both TEST and CONTROL group during the observation period (mean annual failure rate: 1.6%). The most common reasons for failure were chipping-fractures, debonding, cracked-tooth-syndrome and recurrent decay. With regard to the FDI criteria, no significant differences between TEST and CONTROL material occurred for any of the evaluated variables. In the TEST group two restorations had to be repaired and two had to be replaced, in the CONTROL group four restorations had to be replaced.

CONCLUSION

Both materials showed acceptable clinical performance and survival during the 5-year observation period.

CLINICAL SIGNIFICANCE

The use of a nanofilled bulk-fill composite proved to be an aesthetically, functionally and biologically satisfactory alternative in posterior dentition.

Comparative Evaluation of Postoperative Sensitivity Using Three Different Tooth-Colored Restorative Materials in Non-carious Cervical Lesions: A Split-Mouth Design In Vivo Study

Introduction

Three different tooth-colored restorative materials were evaluated and compared for postoperative sensitivity using a split-mouth design. This is a double-blinded clinical trial assessed for a one-month follow-up period in patients with non-carious cervical lesions (NCCLs).

Materials and Methods

A total of 60 NCCLs in 20 participants were considered in this split-mouth design study and randomly divided into three different groups: Flowable composite (n = 20), resin-modified glass ionomer cement (RMGIC) (n = 20), and Zirconomer® (n = 20). The restorations were evaluated for postoperative sensitivity at baseline (BL-day 0), three, seven, and 21 days using the Schiff cold air sensitivity scale. Data were analyzed using IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, United States) using a post hoc test for postoperative sensitivity and one-way Anova to analyze all the groups together at the time interval of three, seven, and 21 days.

Results

In Group 1 (flowable composites) and Group 3 (Zirconomer), a statistically significant difference in terms of reduced postoperative sensitivity was seen after three and seven days. However, a significant reduction in postoperative sensitivity was seen after three, seven, and 21 days in Group 2 (RMGIC).

Conclusion

In this study, RMGIC showed reduced postoperative sensitivity after restoring NCCLs compared to Zirconomer and flowable composites. Compared with flowable composites and Zirconomer, RMGIC showed better clinical performance in terms of less postoperative sensitivity after restoring NCCLs.

The effect of different application modes of a 1-step self-etch adhesive on the clinical performance of Class I composite restorations: A randomized controlled clinical trial

OBJECTIVE

To evaluate the clinical performance of a 1-step self-etch dentin adhesive that was applied according to the manufacturers' recommendations, doubling the adhesive application time and layer in Class I cavities with a composite resin.

MATERIALS AND METHODS

A total of 39 patients aged between 14 and 43 (mean age: 19.1) years were enrolled in the study. Each patient received three restorations. In these three restorations, a 1-step self-etch adhesive was applied according to the manufacturer's recommendations (control group), by doubling the adhesive application time, and with double layers. The restorations were evaluated according to modified USPHS criteria at baseline, and 1, 2, 3, and 4-year recalls.

RESULTS

After 4 years, the success rate was 100% for restorations with the adhesive applied according to the manufacturers' recommendations, 96.9% for restorations applied by doubling the adhesive application time, and 93.8% for restorations applied with double adhesive layers. There was no significant difference between the three application methods among all the evaluation periods regarding the evaluation criteria.

CONCLUSIONS

The 4-year success rates of a 1-step self-etch dentin adhesive that was applied according to the manufacturers' recommendation, by doubling the adhesive application time, and with double layers were excellent.

CLINICAL SIGNIFICANCE

It is not recommended to double the adhesive application time nor apply a double layer of a 1-step self-etch adhesive because it does not improve the clinical performance of Class I composite restorations.

Compliance of randomized controlled trials in posterior restorations with the CONSORT statement: a systematic review of methodology

OBJECTIVES

This study aims to investigate the compliance of randomized controlled trials (RCTs) in posterior restorations with the Consolidated Standards of Reporting Trials Statement (CONSORT) statement and to analyze the risk of bias (RoB) of these studies.

METHODS

A systematic search was performed in PubMed, Scopus, Web of Science, LILACS/BBO, and Cochrane Library. Only RCTs published in peer-reviewed journals were included. The compliance with the CONSORT was evaluated in a 0-2 scale where 0 = no description, 1 = poor description and 2 = adequate description. Descriptive analyses of the CONSORT mean score by journal, country, and RoB were performed. The RoB in RCTs was evaluated by using the Cochrane Collaboration's tool version 1.0.

RESULTS

A total of 15,476 studies were identified after duplicates removal. O only 202 meet the eligibility criteria, among which 31 were follow-up studies. Concerning the overall RoB, only 29 out of 171 were classified as low risk of bias. The overall mean CONSORT score was 19 ± 5.4 points, which means compliance of approximately 59%. Significant differences among countries, publication period, and RoB were observed (p < 0.001). The journal's impact factor was not correlated with the overall CONSORT score (p = 0.36).

CONCLUSIONS

The adherence of RCTs conducted in posterior restorations to the CONSORT Statement is still low. In addition, most studies were classified as at unclear risk of bias. These results call up an urgent need for improvement.

CLINICAL RELEVANCE

Most RCTs conducted in posterior teeth have poor reporting and are mainly classified as having an unclear risk of bias.

Clinical Effectiveness of Bulk-Fill and Conventional Resin Composite Restorations: Systematic Review and Meta-Analysis

The objective of this systematic review and meta-analysis was to determine the clinical effectiveness of bulk-fill and conventional resin in composite restorations. A bibliographic search was carried out until May 2020, in the biomedical databases Pubmed/MEDLINE, EMBASE, Scopus, CENTRAL and Web of Science. The study selection criteria were: randomized clinical trials, in English, with no time limit, with a follow-up greater than or equal to 6 months and that reported the clinical effects (absence of fractures, absence of discoloration or marginal staining, adequate adaptation marginal, absence of post-operative sensitivity, absence of secondary caries, adequate color stability and translucency, proper surface texture, proper anatomical form, adequate tooth integrity without wear, adequate restoration integrity, proper occlusion, absence of inflammation and adequate point of contact) of restorations made with conventional and bulk resins. The risk of bias of the study was analyzed using the Cochrane Manual of Systematic Reviews of Interventions. Sixteen articles were eligible and included in the study. The results indicated that there is no difference between restorations with conventional and bulk resins for the type of restoration, type of tooth restored and restoration technique used. However, further properly designed clinical studies are required in order to reach a better conclusion.

Nanofilled/nanohybrid and hybrid resin-based composite in patients with direct restorations in posterior teeth: A systematic review and meta-analysis

OBJECTIVE

A systematic review and a meta-analysis were performed to answer the following research question: Are there differences in the color match and surface texture of nanofilled/nanohybrid and hybrid composite in patients with direct posterior restorations?

DATA

Randomized clinical trials that compared nanofilled/nanohybrid and hybrid composite in direct restoration in posterior teeth were included. For the analysis of the bias the risk of bias tool (RoB) was used. Meta-analyses of different pairs (nanofilled vs. hybrid and nanohybrid vs. hybrid composite) were conducted for surface texture and color match and other secondary outcomes at different follow-ups, using a random effects model. Heterogeneity was assessed with the Cochran Q test and I² statistics. GRADE was used to assess the quality of the evidence.

SOURCES

A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library and SIGLE, without restrictions. IADR abstracts (2001-2019), unpublished and ongoing trials registries, dissertations and theses were also searched.

STUDY SELECTION

28 studies remained. No study was considered to be at low RoB; four studies were judged to have high RoB, and the remaining were judged to have unclear RoB.

RESULTS

For the primary and secondary outcomes variables no significant differences were detected between nanofilled/nanohybrid restorations and hybrid composite restorations in any of the study follow-ups (p > 0.08). The body of evidence for surface texture and color match was classified as moderate or low.

CONCLUSION

No evidence of difference was found between nanofilled/nanohybrid and hybrid composite in any of the clinical parameters evaluated.

The effect of two composite placement techniques on fracture resistance of MOD restorations with various resin composites

OBJECTIVE

The aim of this in vitro study was to compare the effect of two restorative placement techniques, centripetal incremental technique (CIT) and bulk-fill technique (BT) on the fracture resistance of Class II MOD restorations with various resin composites in molar teeth.

MATERIALS AND METHODS

Fifty-six extracted, caries free third molars were prepared with MOD preparations and restored with resin composites. The specimens were divided into two groups by placement technique, centripetal incremental technique (CIT) and bulk-fill technique (BT). Each group was subdivided into four groups according to resin composite: hybrid (Aelite LS), nano-hybrid (Virtuoso Universal), bulk fill (Filtek One Bulk Fill) and the micro-hybrid (Herculite XRV) as the control.

RESULTS

Two-way analysis of variance test (ANOVA) followed by the multiple comparison procedure, Student-Newman-Keuls Method showed no a statistically significant difference between placement techniques and fracture resistance of Class II resin composite restorations (P > 0.05). Herculite XRV resisted a significantly higher load before fracture than the other three materials at a 0.05 level of significance, while Virtuoso Universal scored the lowest load.

CONCLUSIONS

There was no significant effect of the two placement techniques on the fracture resistance of Class II resin composite restorations CLINICAL SIGNIFICANCE: Resin composite restorations in Class II MODs using a simplified bulk fill placement technique showed no significant difference in fracture resistance with the centripetal technique in molar teeth.

Effects of Ions-Releasing Restorative Materials on the Dentine Bonding Longevity of Modern Universal Adhesives after Load-Cycle and Prolonged Artificial Saliva Aging

This study aimed at evaluating the microtensile bond strength (MTBS) and fractographic features of dentine-bonded specimens created using universal adhesives applied in etch-and-rinse (ER) or self-etching (SE) mode in combination with modern ion-releasing resin-modified glass-ionomer cement (RMGIC)-based materials after load cycling and artificial saliva aging. Two universal adhesives (FTB: Futurabond M+, VOCO, Germany; SCU: Scotchbond Universal, 3M Oral Care, USA) were used. Composite build-ups were made with conventional nano-filled composite (AURA, SDI, Australia), conventional resin-modified glass ionomer cement (Ionolux VOCO, Germany), or a (RMGIC)-based composite (ACTIVA, Pulpdent, USA). The specimens were divided in three groups and immersed in deionized water for 24 h, load-cycled (350,000 cycles; 3 Hz; 70 N), or load-cycled and cut into matchsticks and finally immersed for 8 months in artificial saliva (AS). The specimens were cut into matchsticks and tested for microtensile bond strength. The results were analyzed statistically using three-way ANOVA and Fisher's LSD post hoc test (p < 0.05). Fractographic analysis was performed through stereomicroscope and FE-SEM. FTB showed no significant drop in bond strength after aging. Unlike the conventional composite, the two RMGIC-based materials caused no bond strength reduction in SCU after load-cycle aging and after prolonged aging (8 months). The SEM fractographic analysis showed severe degradation, especially with composite applied on dentine bonded with SCU in ER mode; such degradation was less evident with the two GIC-based materials. The dentine-bond longevity may be influenced by the composition rather than the mode of application (ER vs. SE) of the universal adhesives. Moreover, the choice of the restorative material may play an important role on the longevity of the finalrestoration. Indeed, bioactive GIC-based materials may contribute to maintain the bonding performance of simplified universal adhesives over time, especially when these bonding systems are applied in ER mode.

Effect of Surface Sealant Reapplication on Clinical Performance of HEMA-containing and HEMA-free Self-etch Adhesives: Two-year Results

Purpose:

To evaluate the clinical performance of one-step self-etch adhesives over two years with and without the application of a surface sealant.

Methods and Materials:

In total, 160 restorations in 40 patients were performed for occlusal caries. Each patient received four Class I restorations, which included a 2-hydroxyethyl methacrylate (HEMA)–containing (Clearfil S3 Bond) and HEMA-free (G-aenial Bond) one-step self-etch adhesive system with and without surface sealant. Half of the restored teeth received Fortify Plus (Bisco) surface sealant material, and the other half were polished with Sof-Lex discs only. Two experienced calibrated examiners clinically evaluated the restorations at baseline and at one- and two-year recalls according to the modified US Public Health Service criteria. The filled surface sealant material was reapplied at each evaluation period.

Results:

After two years, none of the restorations had failed. There were no significant differences between the two dentin adhesives with or without a surface sealant application among the evaluation periods. Each dentin adhesive with and without surface sealant showed significant changes from the clinically ideal (Alfa) to clinically acceptable (Bravo) with regard to marginal discoloration, marginal adaptation, and surface texture. Sealed restorations exhibited lower ideal restoration rates with regard to color matching and surface texture and higher ideal restoration rates with respect to marginal adaptation compared with unsealed restorations. In addition, the surface sealant application reduced the marginal discoloration of the HEMA-free one-step self-etch adhesive.

Conclusions:

The two-year success rates of HEMA-containing and HEMA-free self-etch adhesives with and without surface sealing application were excellent. Although the surface sealant application was not effective with regard to changes in color matching and surface texture, it improved the marginal adaptation of the dentin adhesive and the marginal discoloration of a HEMA-free adhesive.

Clinical Evaluation of Fiber-Reinforced Composite Restorations in Posterior Teeth - Results of 2.5 Year Follow-up

Objectives:

The aim of this study was to evaluate the clinical performance of posterior composite restorations reinforced by bulk base of short-fiber composite (everX Posterior, GC Corporation).

Methods:

Thirty-six short fiber-reinforced composite restorations were placed in premolar and molar teeth of 33 patients. Eight of the teeth were vital and 28 were non-vital. Average follow up time of the restorations was 30.6 months (2.5 years), ranging from 16.2 to 51.3 months (1.3 - 4.3 years).

Results:

One restoration failed during the follow-up period due to secondary caries, at time point 39.5 months. Three fillings had minor fractures during the follow-up. The overall survival rate of the restorations was 97.2% and success rate (no maintenance needed) was 88.9%, respectively.

Conclusion:

Posterior composite restorations with a bulk base of short-fiber composite showed good clinical performance in the short term evaluation.

Clinical performance of bulk-fill and conventional resin composite restorations in posterior teeth: a systematic review and meta-analysis

OBJECTIVES

The purpose of this systematic review was to compare the clinical performance of bulk-fill resin composites with conventional resin composites used for direct restorations of posterior teeth.

METHODS

This review followed the PRISMA statement. This review was registered at PROSPERO (registration number CRD42016053436). A search of the scientific literature was performed by two independent reviewers using the PubMed/MEDLINE, Embase, The Cochrane Library, and Web of Science databases from commencement until January 2018. The research question was "Do bulk-fill resin composites have a clinical performance comparable to conventional resin composites in posterior restorations?" Only studies evaluating class I and II direct restorations in permanent teeth with a follow-up period of at least 1 year were included. The RevMan 5 program was used for meta-analysis, calculating the relative risk (RR) and 95% confidence interval (CI) of the dichotomous outcome (restoration failure or success).

RESULTS

Ten articles were selected, comprising 941 analyzed restorations. The mean follow-up period was 33.6 months (12-72 months). No statistically significant differences in the failure rate were observed between conventional and base/flowable bulk-fill resin composites (p = 0.31; RR 1.49; 95% CI 0.69-3.25) or full-body/sculptable bulk-fill resin composites (p = 0.12; RR 1.89; 95% CI 0.84-4.24).

CONCLUSIONS

The present systematic review and meta-analysis indicate similar clinical performances of bulk-fill and conventional resin composites over a follow-up period of 12 to 72 months.

CLINICAL SIGNIFICANCE

Based on the results of this study, the bulk-fill resin composites could be an alternative for direct restorations in posterior teeth. However, clinical trials of longer duration are required.

Do Nanofilled/Nanohybrid Composites Allow for Better Clinical Performance of Direct Restorations Than Traditional Microhybrid Composites? A Systematic Review

This systematic review was carried out to assess the clinical effectiveness of nanofilled and nanohybrid composites used for direct restorations in comparison with microhybrid composites. The guidelines for the preferred reporting items for systematic reviews and meta-analyses were followed. A search of articles published from July 1996 to February 2017 was performed in PubMed, SciVerse Scopus, Latin American and Caribbean Health Sciences, the Scientific Electronic Library Online, and the Cochrane Library. The present review selected only randomized controlled trials comparing the clinical performance of a nanofilled or nanohybrid composite for direct restorations with that of a microhybrid composite. The research found 201 studies. Twenty-one articles fulfilled the criteria of the present review. However, the included studies were characterized by great methodological diversities. As a general trend, nanofilled and nanohybrid composites were found to be capable of clinical performance, marginal quality, and resistance to wear similar to that of traditional composites without showing improved surface characteristics. The risk of bias of included studies was judged unclear or high. The clinical performance of nanofilled/nanohybrid composites was found to be comparable to that of traditional composites in the posterior area. The data concerning anterior and cervical restorations were insufficient. With regard to the esthetic properties, there is a compelling need for studies on anterior teeth in which the operators are kept unaware of the restorative material. Nanofilled/nanohybrid composites seem to be a valid alternative to traditional microhybrid composites, and at the moment, there is low-level evidence attesting a lack of their superiority.

Nanofilled Resin Composite Properties and Clinical Performance: A Review

The aim of this review was to compile recent evidence related to nanofilled resin composite materials regarding the properties and clinical performance. Special attention was given to mechanical properties, such as strength, hardness, abrasive wear, water sorption, and solubility. The clinical performance of nanocomposite materials compared with hybrid resin composites was also addressed in terms of retention and success rates, marginal adaptation, color match, and surface roughness. A search of English peer-reviewed dental literature (2003-2017) from PubMed and MEDLINE databases was conducted using the terms "nanocomposites" or "nanofilled resin composite" and "clinical evaluation." The list was screened, and 82 papers that were relevant to the objectives of this work were included in the review. Mechanical properties of nanocomposites are generally comparable to those of hybrid composites but higher than microfilled composites. Nanocomposites presented lower abrasive wear than hybrids but higher sorption values. Their clinical performance was comparable to that of hybrid composites.

Clinical performance of Class I nanohybrid composite restorations with resin-modified glass-ionomer liner and flowable composite liner: A randomized clinical trial

Background:

Liners play a vital role in minimizing polymerization shrinkage stress by elastic bonding concept and increase the longevity and favorable outcome for composite restorations.

Aims:

The aim of this study was to evaluate the clinical performance of nanohybrid composite restorations using resin-modified glass-ionomer and flowable composite liners.

Settings and Design:

A single-centered, double-blinded randomized clinical trial, with split-mouth design and equal allocation ratio that was conducted in the Department of Conservative Dentistry and Endodontics.

Materials and Methods:

In forty patients, a total of eighty Class I restorations were placed with resin-modified glass-ionomer cement (RMGIC) liner (FUJI II LC, GC America) in one group and flowable composite liner (smart dentin replacement/SDR, Dentsply Caulk, Milford, DE, USA) in another group. All restorations were clinically evaluated by two examiners, immediately (baseline), 3, 6, and 12 months using US Public Health Service modified criteria.

Statistical Analysis Used:

Statistical analysis was performed using McNemar's test (P < 0.05).

Results:

There was no significant difference in the color match, marginal discoloration, surface roughness, and marginal adaptation. Restorations with RMGIC liner group show 20% Bravo scores on anatomic form at 12 months but are still clinically acceptable.

Conclusion:

Nanohybrid composite restorations with RMGIC (Fuji II LC) and flowable composite liner (SDR) demonstrated clinically acceptable performance after 12 months.

Degradation in the fatigue crack growth resistance of human dentin by lactic acid

The oral cavity frequently undergoes localized changes in chemistry and level of acidity, which threatens the integrity of the restorative material and supporting hard tissue. The focus of this study was to evaluate the changes in fatigue crack growth resistance of dentin and toughening mechanisms caused by lactic acid exposure. Compact tension specimens of human dentin were prepared from unrestored molars and subjected to Mode I opening mode cyclic loads. Fatigue crack growth was achieved in samples from mid- and outer-coronal dentin immersed in either a lactic acid solution or neutral conditions. An additional evaluation of the influence of sealing the lumens by dental adhesive was also conducted. A hybrid analysis combining experimental results and finite element modeling quantified the contribution of the toughening mechanisms for both environments. The fatigue crack growth responses showed that exposure to lactic acid caused a significant reduction (p≤0.05) of the stress intensity threshold for cyclic crack extension, and a significant increase (p≤0.05) in the incremental fatigue crack growth rate for both regions of coronal dentin. Sealing the lumens had negligible influence on the fatigue resistance. The hybrid analysis showed that the acidic solution was most detrimental to the extrinsic toughening mechanisms, and the magnitude of crack closure stresses operating in the crack wake. Exposing dentin to acidic environments contributes to the development of caries, but it also increases the chance of tooth fractures via fatigue-related failure and at lower mastication forces.

Two-year clinical evaluation of resin composite in posterior teeth: A randomized controlled study

BACKGROUND

Clinical evaluations as fundamental method to prove the efficiency of restorative materials.

AIM

This study evaluated the clinical performance of restorative systems during 2 years of clinical service.

MATERIALS AND METHODS

This study assessed the clinical performance of restorative systems (Filtek Z250 and P60), during 2 years of clinical service, using the US Public Health Service system. The randomized and double-blind study comprising thirty volunteers. The restorations were evaluated at baseline, 6, 12, and 24 months. It was used the following criteria: marginal discoloration (MD), marginal integrity (MI), superficial texture (ST), wear (W), postoperative sensitivity (PS) and recurrent caries (RC).

RESULTS

Statistic analysis was performed using Fisher's and McNemar's exact tests and Pearsons's Chi-square in a significance level of 5%. The results at baseline and 24 months for Group I were: MD - 100, 100%; MI - 100, 88.6%; ST - 100, 94.3%; W - 100, 94.3%; PS - 100, 100%; RC - 100, 100%, of alpha scores; Group II: MD - 100, 97.1%; MI - 100, 91.4%; ST - 100, 94.3%; W - 100, 91.4%; PS - 100, 100%; RC - 100, 100%, of alpha scores. It was observed no statistical difference in the evaluated criteria and period.

CONCLUSIONS

After 24 months of evaluation, both restorative systems exhibited acceptable clinical performance.

Bulk dentine replacement versus incrementally placed resin composite: A randomised controlled clinical trial

OBJECTIVE

This randomized controlled clinical trial compared two techniques and materials for restoring carious teeth-Bulk dentine replacement versus incremental placement of a hybrid posterior resin composite material in terms of patient comfort (post operative sensitivity and tenderness on biting).

MATERIAL AND METHODS

Seventy-two carious teeth were randomized to one of two treatment groups: Group A-were restored with a bulk dentine replacement material or Group B-restored with incrementally placed hybrid composite. Patients were followed up by way of a structured phone call at day 2 and day 7 post-operatively. Patients reporting discomfort at day 7 were subsequently followed up on days 14, and 30.

RESULTS

All patients were followed up. At day 2, 18/72 restored teeth had post-operative sensitivity; this figure fell to 10/72 at day 7. A Chi squared test revealed that at day 2 a greater level of sensitivity was reported by patients in Group A (P=0.029). However, at day 7 there was no statistically significant difference between the two groups in terms of sensitivity (P=0.453). 8/72 and 6 /72 teeth had tenderness to biting at days 2 and 7 respectively. A Chi squared test revealed no statistically significant difference between the two groups in terms of tenderness on biting at any time period (P=0.722). Interestingly, Class I cavities were found to be more tender on biting than Class II cavities. At day 30 2/72 teeth exhibited sensitivity and none of the teeth exhibiting tenderness on biting.

CONCLUSION

At day 7 there was no significant difference between the two groups in terms of postoperative sensitivity and tenderness on biting.

Effect of resin-modified glass-ionomer cement lining and composite layering technique on the adhesive interface of lateral wall

Interface integrity can be maintained by setting the composite in a layering technique and using liners.

Survival of direct resin restorations in posterior teeth within a 19-year period (1996-2015): A meta-analysis of prospective studies

OBJECTIVES

The aim of this study is to analyze the survival of posterior composite restorations published within the last 19 years (1996-2015).

METHODS

In this study only prospective, clinical trials with specification of the failure rate according to Class I/II composite fillings were included. Studies were analyzed according to the observation period (all studies vs. short-term vs. long-term studies). Retrospective studies and/or open laminate studies, tunnel restorations and Class V restorations were excluded. The following variables possibly influencing the failure rate were extracted from the studies: observation period, recall rate, average age of patients, number of patients, ratio of Class I/II fillings, number of restorations, ratio of premolars/molars, operator, method of isolation, bonding generation and filler size.

RESULTS

A total of 88 studies were included for statistical analysis. The observation period of the studies varied between 1 and 17 years, while most of the studies did not last longer than 5 years. Fracture of the restorations, secondary caries and marginal gap are the main causes for failure in the first 5 years (in descending order), while fracture and secondary caries are similarly distributed in long-term studies. Variables of investigation differed greatly in significance according to the respective observation period. The observation period, the recall rate, the ratio of Class I/II fillings and the number of restorations and patients had a significant influence on the overall failure rate when including all studies (short- and long-term). A linear correlation between the observation period and the failure rate was observed. In long-term studies these variables were not significant any longer. No significant difference in the failure rates between the materials per study was observed. The most common commercial composites investigated were: Tetric Ceram, Surefil, Filtek Supreme (incl. XT), Filtek Z250. The mean annual failure rate was 1.46% (±1.74%) for short-term studies and 1.97% (±1.53) for long-term studies. There is still a big need for clinical studies lasting longer than 5 years, as failure rates of composite restorations in posterior teeth increases with longer observation periods.

SIGNIFICANCE

A decreasing failure rate with an increasing recall rate as observed in our study suggests a patient selection in regard to availability and dental awareness. Internationally standardized evaluation criteria are mandatory in order to allow comparisons of the outcomes of clinical studies.

Resin composite class I restorations: a 54-month randomized clinical trial

The objective of this longitudinal clinical randomized trial was to evaluate the clinical performance of a nanofilled and a nanohybrid resin composite in Class I occlusal restorations of posterior teeth over the course of 54 months. Forty-one adolescents participated in the study. The teeth were restored with Adper Single Bond 2 (3M ESPE) and nanofilled (Filtek Z350, 3M ESPE), nanohybrid (Esthet-X, Dentsply) and microhybrid Filtek Z250 (3M ESPE) used as a control. After 54 months, the restorations were evaluated in accordance with the modified United States Public Health Service criteria. The McNemar and Friedman tests were used for statistical analysis, at a level of significance of 5%. Five failed restorations were observed during the follow-up. A change to unacceptable restoration occurred for one Esthet-X, two Filtek Z350, and two Filtek Z250 restorations, which received the clinically unacceptable score, Charlie, for both anatomic form and marginal adaptation. Secondary caries and postoperative sensitivity occurred in one Filtek Z250 and one Filtek Z350 restoration. When the five evaluation periods (baseline and six, 12, 30, and 54 months) were compared, significant differences were found in the marginal adaptation of Filtek Z250 and Filtek Z350. Significant differences in the roughness criteria (p=0.005) were also observed when the three composites were compared after 54 months (Filtek Z350 > Filtek Z250 > Esthet-X), always within clinically acceptable limits. The materials investigated showed acceptable clinical performance for Class I restoration after 54 months. Long-term reevaluations are necessary for a more detailed analysis of these composites.

The effect of clinical performance on the survival estimates of direct restorations

Objectives

In most retrospective studies, the clinical performance of restorations had not been considered in survival analysis. This study investigated the effect of including the clinically unacceptable cases according to modified United States Public Health Service (USPHS) criteria into the failed data on the survival analysis of direct restorations as to the longevity and prognostic variables.

Materials and Methods

Nine hundred and sixty-seven direct restorations were evaluated. The data of 204 retreated restorations were collected from the records, and clinical performance of 763 restorations in function was evaluated according to modified USPHS criteria by two observers. The longevity and prognostic variables of the restorations were compared with a factor of involving clinically unacceptable cases into the failures using Kaplan-Meier survival analysis and Cox proportional hazard model.

Results

The median survival times of amalgam, composite resin and glass ionomer were 11.8, 11.0 and 6.8 years, respectively. Glass ionomer showed significantly lower longevity than composite resin and amalgam. When clinically unacceptable restorations were included into the failure, the median survival times of them decreased to 8.9, 9.7 and 6.4 years, respectively.

Conclusions

After considering the clinical performance, composite resin was the only material that showed a difference in the longevity (p < 0.05) and the significantly higher relative risk of student group than professor group disappeared in operator groups. Even in the design of retrospective study, clinical evaluation needs to be included.

A 7-year randomized prospective study of a one-step self-etching adhesive in non-carious cervical lesions. The effect of curing modes and restorative material

OBJECTIVE

The aim of this study was to evaluate the clinical retention of a one-step self-etching adhesive system (Xeno III) in Class V non-carious cervical lesions and the effect of restorative material and curing techniques on longevity of the restorations.

MATERIALS AND METHODS

A total of 139 Class V restorations were placed with the self-etching primer Xeno III and a resin composite (Tetric Ceram) or a poly-acid modified resin composite (Dyract AP) in non-carious cervical lesions without intentional enamel involvement. The materials were cured with a conventional continuous light, a soft-start or a pulse-delay curing mode. The restorations were evaluated at baseline, 6, 12, 18 and 24 months and then yearly during a 7 year follow-up with modified USPHS criteria. Dentine bonding efficiency was determined by the percentage of lost restorations.

RESULTS

During the 7 years, 135 restorations could be evaluated. No post-operative sensitivity was reported by the participants. Overall relative cumulative loss rate frequencies for the adhesive system at 6 and 18 months and 7 years, independent of curing technique and restorative material, were 0.8%, 6.9% and 23.0%, respectively. The self-etching adhesive fulfilled at 18 months the full acceptance ADA criteria. Tetric Ceram showed at 7 years a 20.9% loss of retention and Dyract AP a 25.0% loss rate (Log rank p = 0.48). The loss rates for the 3 curing techniques: continuous, soft start and pulse delay were 17%, 27.9% and 24.4%, respectively (Log rank p = 0.52). No secondary caries was observed.

SIGNIFICANCE

The single-step self-etching adhesive showed acceptable clinical long-time retention rates to dentine surfaces independent of restorative material and curing technique used.