Clinical evaluation of two one-bottle dentin adhesives at three years

Clinical performance of preheating thermoviscous composite resin for non-carious cervical lesions restoration: A 24-month randomized clinical trial

OBJECTIVES

This 24-month, double-blind, split-mouth randomized clinical trial aimed to compare the retention rates of a preheated thermoviscous composite resin (PHT) compared to a non-heated composite resin (NHT) in non-carious cervical lesions (NCCLs).

METHODS

A total of 120 restorations were restored on NCCLs using a preheated (VisCalor bulk, Voco GmbH) and a non-heated (Admira Fusion, Voco GmbH) composite resins with 60 restorations per group. A universal adhesive in the selective enamel conditioning was applied. In the PHT group, composite was heated at 68 °C for using a bench heater. In the NHT group, no heating was employed. Both restorative materials were dispensed into caps and inserted into the NCCLs. The restorations were evaluated at baseline, 6, 12, 18, and after 24 months of clinical service using the FDI criteria. Statistical analysis was performed with Kaplan-Meier estimation analysis for retention/fracture rate and Chi-square test for the other FDI parameters (α=0.05).

RESULTS

After 24 months 108 restorations were assessed. Seven restorations were lost (two for PHT group and five for NHT group), and the retention rates (95 % confidence interval [CI]) were 96.7 % (81.5-99.9) for PHT group and 90.8 % (81.1-96.0) for NHT group, with no statistical differences between them (p > 0.05). The hazard ratio (95 % CI) was 0.52 (0.27 to 1.01), with no significant difference within groups. In terms of all other FDI parameters that were assessed, all restorations were deemed clinically acceptable.

CONCLUSIONS

Both composites showed high rates of retention rates after 24 months.

CLINICAL SIGNIFICANCE

The clinical performance of the new preheated thermoviscous was found to be as good as the non-heated composite after 24-month of clinical evaluation in non-carious cervical lesions.

REGISTRATION OF CLINICAL TRIALS

RBR-6d6gxxz.

Various ways of pre-heating a bulk-fill thermoviscous composite in restoration in non-carious cervical lesions: 12-month randomized clinical trial

OBJECTIVE

The objective of the study is to evaluate through a randomized clinical trial the best method to preheat a composite resin, if using a Caps dispenser device associated with Caps Warmer (CD) or with a VisCalor Caps dispenser/warmer (VD) for restorations in non-carious cervical lesions (NCCLs).

MATERIAL AND METHODS

One hundred and twenty restorations were distributed to two groups (n = 60) according to the pre-heating way of thermoviscous bulk-fill composite resin. For the CD group, pre-heating was carried at 68 °C using a heating bench for 3 min. For the VD group, pre-heating was performed at 68 °C using a heating gun for 30 s. After that, pre-heated bulk-fill composites were directly inserted in the NCCLs. The total working time was recorded. The restorations were evaluated after 6 and 12 months of clinical performance according to the FDI criteria. Statistical analysis was performed using the Student's t test for unpaired samples for working time, and the Chi-square test for restoration clinical performance (α = 0.05).

RESULTS

Working time was shorter for VD with a statistically significant difference compared to CD (p = 0.01). Few restorations were lost or fractured after 12 months of clinical evaluation (p > 0.05). The retention rates were 96.7% (CI 95 %: 88.6-99.1%) for CD and 98.3% (CI 95 %: 91.1-99.7%) for VD. The other FDI parameters were considered clinically acceptable.

CONCLUSIONS

The different pre-heating ways did not influence the clinical performance of thermoviscous bulk-fill composite restorations in NCCLs after 12 months.

CLINICAL RELEVANCE

Regardless of the bulk-fill thermoviscous composite resin pre-heating ways, the restorations are clinically acceptable after 12 months.

Noncarious cervical lesions: Morphology and progression, prevalence, etiology, pathophysiology, and clinical guidelines for restoration

PURPOSE

To synthesize the literature regarding noncarious cervical lesions (NCCLs) and propose clinical guidelines when lesion restoration is indicated.

MATERIAL AND METHODS

A PubMed search was performed related to NCCL morphology, progression, prevalence, etiology, pathophysiology, and restoration.

RESULTS

NCCLs form as either rounded (saucerlike) depressions with smooth, featureless surfaces that progress mainly in height or as V-shaped indentations that increase in both height and depth. Prevalence ranges from less than 10% to over 90% and increases with age. Common locations are the facial surfaces of maxillary premolars. They have a multifactorial etiology due to personal habits such as excessive horizontal toothbrushing and consumption of acidic foods and drinks. Occlusal factors have been identified as contributing to the prevalence of NCCLs in some studies, whereas other studies indicate there is no relationship. The concept of abfraction has been proposed whereby mechanical stress from occlusal loading plays a role in the development and progression of NCCLs with publications supporting the concept and others indicating it lacks the required clinical documentation. Regardless of the development mechanism, demineralization occurs and they are one of the most common demineralization diseases in the body. Treatment should be managed conservatively through preventive intervention with restorative treatment delayed until it becomes necessary due to factors such as lesion progression, impact on patient's quality of life, sensitivity, poor esthetics, and food collection may necessitate restoration. Composite resins are commonly used to restore NCCLs although other materials such as glass ionomer and resin-modified glass ionomer are also used. Sclerotic dentin does not etch like normal dentin and therefore it has been recommended to texture the dentin surface with a fine rotary diamond instrument to improve restoration retention. Some clinicians use mechanical retention to increase retention. Beveling of enamel is used to increase the bonding area and retention as well as enhance the esthetic result by gradually creating a color change between the restoration and tooth. Both multistep and single-step adhesives have been used. Dentin etching should be increased to 30 seconds due to the sclerotic dentin with the adhesive agent applied using a light scrubbing motion for 20 seconds but without excessive force that induces substantial bending of a disposable applicator. Both flowable and sculptable composite resins have been successfully used with some clinicians applying and polymerizing a layer of flowable composite resin and then adding an external layer of sculptable composite resin to provide enhanced resistance to wear. When caries is present, silver diamine fluoride has been used to arrest the caries rather than restore the lesion.

CONCLUSIONS

Noncarious cervical lesions (NCCLs) form as smooth saucerlike depressions or as V-shaped notches. Prevalence values as high as 90% and as low as 10% have been reported due to habits such as excessive toothbrushing and an acidic diet. Occlusal factors have been proposed as contributing to their presence but it remains controversial. Publications have both supported and challenged the concept of abfraction. They are one of the most common demineralization diseases in the body. Conservative treatment through prevention is recommended with restorative treatment delayed as long as possible. When treatment is needed, composite resins are commonly used with proposed restorative guidelines including texturing the sclerotic dentin, beveling the enamel, potential use of mechanical retention, 30 seconds of acid etching, and use of either multistep or single-step adhesives in conjunction with a light scrubbing motion for 20 seconds without excessive force placed on disposable applicators.

Progression of non-carious cervical lesions: 3D morphological analysis

OBJECTIVES

This longitudinal study aimed to investigate morphologically and quantitatively the progression of non-carious cervical lesions (NCCLs) using a confocal laser scanning microscope (CLSM) and replica models.

MATERIALS AND METHODS

The samples examined comprised sets of replicas annually obtained from 83 lesions in 16 participants over 3 to 5 years. All lesions were visually categorized as wedge-shaped, saucer-shaped, or mixed-shaped lesions. CLSM images of the replicas were analyzed in terms of axial depth, occlusogingival width (height) in the buccolingual cross-section, and estimated volume using a custom code of the image analysis software to estimate the progression of the NCCLs over time. The morphological characteristics of the NCCLs were also objectively divided into three groups according to the depth to height ratio (D/H ratio). Fisher's exact test and the Cochran-Armitage trend test were used for statistical analysis.

RESULTS

Saucer-shaped lesions progressed mainly in height, whereas wedge-shaped lesions increased both in height and depth. Annual progression in depth and volume significantly increased as the D/H ratio increased. More than half of the NCCLs with a small D/H ratio progressed 50 μm or more in height, whereas none of them progressed more than 50 μm in depth. Annual progression in depth significantly increased as the lesion depth at baseline increased.

CONCLUSIONS

Progression patterns significantly differed between NCCLs of different shapes. Most NCCLs progressed slowly in depth regardless of their shape. Moreover, NCCLs may progress through active and inactive stages.

Does the Type of Solvent in Dental Adhesives Influence the Clinical Performance of Composite Restorations Placed in Noncarious Cervical Lesions? A Systematic Review and Meta-analysis

CLINICAL RELEVANCE

According to the clinical and scientific evidence presented in this systematic review and meta-analysis, dental adhesives containing either organic solvent (acetone or alcohol) can be used to achieve similar clinical performance and longevity of composite restorations.

SUMMARY

Objectives: This systematic review and meta-analysis compared the clinical performance and survival rates of composite restorations placed in noncarious cervical lesions (NCCLs) using dental adhesives containing acetone or alcohol-based solvents.Methods and Materials: PubMed, Scopus, Web of Science, Virtual Health Library (VHL) LILACS, Cochrane Library, OpenGrey, Clinical Trials, and Rebec were searched. MeSH terms, supplementary concepts, synonyms, and free keywords were used in the search strategy. All references were crosschecked by two independent investigators following the PICOS strategy (population, NCCLs; intervention, acetone-based bonding agent; comparison, alcohol-based bonding agent; outcome, clinical evaluation parameters and survival rates; study design, randomized controlled clinical trials). Cochrane Collaboration's tool was used to assess risk of bias, and two distinct meta-analyses were performed using the RevMan software. The prevalence of success and the total number of restorations for each group (acetone- or alcohol-based) were used to calculate the risk difference at a confidence interval of 95%. Random-effects models were applied, and heterogeneity was assessed using the I2 index in the pooled and subgrouped meta-analyses. The certainty of evidence was evaluated through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.Results: A total of 7876 studies were retrieved, from which 27 studies were selected for the systematic review. Ten studies were classified as "low risk of bias" and included in the meta-analyses. Overall heterogeneity was not significant (I2 = 0.00%). The clinical performance of restorations placed with bonding agents based on both solvents for each of the available parameters presented no statistical significance for any of the meta-analyses (p>0.05).Conclusion: Scientific evidence suggests composite restorations placed with acetone or alcohol-based dental adhesives present similar clinical performance and survival rates in NCCLs.

Randomized clinical trial of four adhesion strategies: A 42 month study

Context

The adhesives clinical effectiveness has been extensively reported for noncarious cervical lesions (NCCLs). However, there is a lack of information about the adhesive systems strategies and their effect on NCCL restoration longevity.

Aims

This study aims to evaluate a 42-month performance of four dentin adhesive systems used for the restorative treatment of NCCLs.

Settings and Design

NCCLs were randomly divided into four groups: (1) Scotchbond multi-purpose (MP); 2: Single bond plus (SB); 3: Scotchbond SE (SE); and 4: Easy bond (EB).

Subjects and Methods

NCCLs (125) were randomly distributed: (1) MP; (2) SB; (3) SE; and (4) EB and were restored with a nanofilled resin-composite, evaluated along 18-36-42 months.

Statistical Analysis Used

Kruskal-Wallis test: Comparison among the adhesive systems in each period. Friedman analysis: Comparison along the periods. Kaplan-Meier: Survival analysis.

Results

Baseline and 42-month retention (RET) rates (%) were 100/100 for MP; 100/94.74 for SB; 100/87.5 for SE; and 100/100 for EB. The cumulative failure percentage was 9.52% for MP, 9.52% SB, 15.8% SE, and 10% EB. Restorations survival was not dependent on the used adhesive type. Marginal adaptation (MA) was similar to each group, but EB presented noticeable marginal deterioration. Wear was noticed in the 3-step etch-and-rinse (MP) restorations evaluated after 42 months. For the EB, baseline and 18-month wear evaluation were statistically similar. After 36 and 42 months, wear was also similar for EB.

Conclusions

Adhesive systems showed similar performance within most important adhesive bonding efficiency achievement parameters: RET, MA, interfacial staining, recurrent caries, and postoperative sensitivity evaluated during 42 months.

Compliance of Randomized Clinical Trials in Noncarious Cervical Lesions With the CONSORT Statement: A Systematic Review of Methodology

The literature was reviewed to evaluate the compliance of randomized clinical trials (RCTs) with the CONsolidated Standards of Reporting Trials (CONSORT ) and the risk of bias of these studies through the Cochrane Collaboration risk of bias tool (CCRT). RCTs were searched at Cochrane Library, PubMed, and other electronic databases to find studies about adhesive systems for cervical lesions. The compliance of the articles with CONSORT was evaluated using the following scale: 0 = no description, 1 = poor description, and 2 = adequate description. Descriptive analyses about the number of studies by journal, follow-up period, country, and quality assessments were performed with CCRT for assessing risk of bias in RCTs. One hundred thirty-eight RCTs were left for assessment. More than 30% of the studies received scores of 0 or 1. Flow chart, effect size, allocation concealment, and sample size were more critical items, with 80% receiving a score of 0. The overall CONSORT score for the included studies was 15.0 ± 4.8 points, which represents 46.9% of the maximum CONSORT score. A significant difference among countries was observed (p<0.001), as well as range of year (p<0.001). Only 4.3% of the studies were judged as at low risk; 36.2% were classified as having unclear risk and 59.4% as having high risk of bias. The adherence of RCTs evaluating adhesive systems to the CONSORT is low with unclear/high risk of bias.

A Critical Review of the Durability of Adhesion to Tooth Tissue: Methods and Results

The immediate bonding effectiveness of contemporary adhesives is quite favorable, regardless of the approach used. In the long term, the bonding effectiveness of some adhesives drops dramatically, whereas the bond strengths of other adhesives are more stable. This review examines the fundamental processes that cause the adhesion of biomaterials to enamel and dentin to degrade with time. Non-carious class V clinical trials remain the ultimate test method for the assessment of bonding effectiveness, but in addition to being high-cost, they are time- and labor-consuming, and they provide little information on the true cause of clinical failure. Therefore, several laboratory protocols were developed to predict bond durability. This paper critically appraises methodologies that focus on chemical degradation patterns of hydrolysis and elution of interface components, as well as mechanically oriented test set-ups, such as fatigue and fracture toughness measurements. A correlation of in vitro and in vivo data revealed that, currently, the most validated method to assess adhesion durability involves aging of micro-specimens of biomaterials bonded to either enamel or dentin. After about 3 months, all classes of adhesives exhibited mechanical and morphological evidence of degradation that resembles in vivo aging effects. A comparison of contemporary adhesives revealed that the three-step etch-and-rinse adhesives remain the ‘gold standard’ in terms of durability. Any kind of simplification in the clinical application procedure results in loss of bonding effectiveness. Only the two-step self-etch adhesives approach the gold standard and do have some additional clinical benefits.

Influence of Isolation Method of the Operative Field on Gingival Damage, Patients' Preference, and Restoration Retention in Noncarious Cervical Lesions

OBJECTIVES

To evaluate the retention rates, gingival damage, and patients' preferences for adhesive restorations in noncarious cervical lesions (NCCL) associated with the use of rubber dam vs cotton rolls/retraction cord isolation.

METHODS

Thirty patients having one pair of similar NCCL on opposing sides of the same arch were enrolled in this study. A total of 60 restorations were placed. In each patient one restoration was placed under rubber dam isolation (RD) using dental retainers, and the other one was placed using cotton rolls/retraction cord (CR/RC) isolation. Dental residents with more than 10 years of clinical experience restored all NCCL using the same adhesive (GO!, SDI Limited, Bayswater, Australia) and composite resin (Ice, SDI). The patients' preferences were recorded. The gingival condition (bleeding, gingival laceration, and gingival insertion level) was evaluated immediately after the restorative procedure and after one week. Gingival sensitivity was also assessed one week after the end of the restorative procedures. The clinical time required to perform each restoration was recorded. The performance of the restorations was assessed using the FDI criteria at baseline and six, 12, and 18 months after clinical service. All criteria evaluated were submitted to appropriate statistical analysis (α=0.05).

RESULTS

The retention rates of the restorations at each recall time were not affected by the isolation method (p>0.05). No significant difference between isolation methods was found in regard to patients' preferences (p=0.86), gingival bleeding (p=0.57), laceration (p=0.64), insertion (p>0.52), gingival sensitivity (p=0.52), or chairside time (p=0.77).

CONCLUSIONS

The use of CR/RC was shown to be similar to the use of RD in terms of retention rates, patient's preference, gingival damage, and chairside time for adhesive restorations in NCCL.

Retention of tooth-colored restorations in non-carious cervical lesions--a systematic review

OBJECTIVES

The aim of this review was to assess the effect of different adhesive systems and tooth preparation on the retention of tooth-colored restorative materials placed in non-carious cervical lesions (NCCLs).

METHODS

Randomized clinical trials with a minimum of 3 years of follow-up that evaluated the effectiveness of tooth-colored materials, adhesive systems, and preparation techniques for the restoration of NCCLs were selected. The Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE (OVID), the Latin American and Caribbean Health Sciences Literature database (LILACS), and Medline (OVID) electronic databases were searched from 1990 to 2013.

RESULTS

Twenty-seven randomized clinical trials were included and reviewed. Meta-analysis was used to determine the relative risk of loss of tooth-colored NCCL restorations between different categories of adhesive systems. The effect of tooth preparation could not be similarly analyzed.

CONCLUSION

The current best evidence indicates that a glass ionomer cement has a significantly lower risk of loss of a NCCL restoration compared to either a three-step etch-and-rinse or a two-step etch-and-rinse adhesive system; a three-step etch-and-rinse adhesive system has a significantly lower risk of loss of a NCCL restoration compared to a two-step etch-and-rinse adhesive system. No significant difference could be observed in the risk of loss of a tooth-colored NCCL restoration between a three-step etch-and-rinse adhesive system and either a two-step self-etch or a one-step self-etch adhesive system.

Shear Bond Strength of Composite to Deep Dentin After Treatment With Two Different Collagen Cross-linking Agents at Varying Time Intervals

Objective

This in vitro study evaluated the shear bond strength of composite resin to deep dentin using a total etch adhesive after treatment with two collagen cross-linking agents at varying time intervals.

Materials and Methods

Thirty freshly extracted human maxillary central incisors were sectioned longitudinally into equal mesial and distal halves (n=60). The proximal deep dentin was exposed, maintaining a remaining dentin thickness (RDT) of approximately 1 mm. The specimens were randomly divided into three groups based on the surface treatment of dentin prior to bonding as follows: group I (n=12, control): no prior dentin surface treatment; group II (n=24): dentin surface pretreated with 10% sodium ascorbate; and group III (n=24): dentin surface pretreated with 6.5% proanthocyanidin. Groups II and III were further subdivided into two subgroups of 12 specimens each, based on the pretreatment time of five minutes (subgroup A) and 10 minutes (subgroup B). Shear bond strength of the specimens was tested with a universal testing machine, and the data were statistically analyzed.

Results

Significantly higher shear bond strength to deep dentin was observed in teeth treated with 10% sodium ascorbate (group II) and 6.5% proanthocyanidin (group III) compared to the control group (group I). Among the collagen cross-linkers used, specimens treated with proanthocyanidin showed significantly higher shear bond strength values than those treated with sodium ascorbate. No significant difference was observed between the five-minute and 10-minute pretreatment times in groups II and III.

Conclusion

It can be concluded that dentin surface pretreatment with both 10% sodium ascorbate and 6.5% proanthocyanidin resulted in significant improvement in bond strength of resin composite to deep dentin.

Clinical Evaluation of Stress-reducing Direct Composite Restorations in Structurally Compromised Molars: A 2-year Report

Objective

To evaluate the clinical performance of class II large-size direct composite restorations.

Materials and Methods

Fifty (50) patients 18 years or older were included in this clinical trial restoring 75 vital molar teeth with large-size cavities.

Inclusion Criteria

Occlusal extension greater than two-thirds the intercuspal distance and proximal extension greater than half the distance between line angles. Teeth with residual cavity walls less than 1 mm and with one or more cusps involved were excluded. Teeth were randomly divided in three groups. Group 1: Opti-Bond FL; group 2: Scotchbond 1 XT; group 3: PQ1. Total-etching was performed using 35% phosphoric acid followed by the application of 2% chlorhexidine gluconate in the three groups. All teeth were restored using Vit-l-escence microhybrid composite resin. The proximal surface was built up first, followed by dentin and enamel occlusal surface stratification; wedge-shaped increments of composite resin were placed and cured using the UltraLume V curing light through a combination of pulse and progressive curing techniques.

Results

Restorations were evaluated at six-month intervals during the two-year period using a modified US Public Health Service criteria by two independent evaluators precalibrated at 85% reliability. No failures were reported and α scores were recorded for all parameters. Statistical analysis was performed using a χ2 test and the Fisher exact test (χ2=10.6; p=0.001). No teeth exhibited sensitivity in the three groups both at the two-week recall and two-year follow-up.

Cross-Compatibility of Methacrylate-Based Resin Composites and Etch-and-Rinse One-Bottle Adhesives

Cross-compatibility between different combinations of methacrylate-based resin composites and etch-and-rinse one-bottle adhesives was evidenced for products from different manufacturers. This represents a desirable property of adhesives as it allows the flexibility to select different composite systems based on the specific restorative needs.

Degree of conversion of two dentin bonding agents with and without a desensitizing agent using fourier transform infrared spectroscopy: An in vitro study

Objective:

This in vitro study investigated the effect of a desensitizer on the degree of conversion of two bonding resins using Fourier transform infrared (FTIR) spectroscopy.

Materials and Methods:

An etch-and-rise bonding resin and a self-etching adhesive resin were selected for the study. Vivasens (Ivoclar Vivadent) was used as a desensitizing agent. Grouping was done as follows: Group I: Adper Single Bond (n=10), Group II: Adper Single Bond + Vivasens (n=10), Group III: AdheSE One (n=10), Group IV: AdheSE One + Vivasens (n=10). The bonding resin alone was light cured for 20 seconds in groups I and III. For groups II and IV, 1 ml each of the bonding resin and the desensitizer was mixed in a vial and light cured for 20 seconds. The specimens were analysed using FTIR spectroscopy.

Results:

Group II (Adper Single Bond + Vivasens) showed a significantly higher degree of conversion compared to Group I (Adper Single Bond). Comparing Groups III and IV, Group IV (AdheSE One + Vivasens) showed a significantly higher degree of conversion compared to Group III (AdheSE One).

Conclusions:

The degree of conversion is increased when a dentin bonding agent is used along with a desensitizer. Hence, this combination can be recommended to effectively control postoperative sensitivity.

24-month clinical evaluation in non-carious cervical lesions of a two-step etch-and-rinse adhesive applied using a rubbing motion

The aim of this clinical trial was to evaluate the effects of application mode on the clinical performance of a two-step etch-and-rinse adhesive in class V cavities over 24 months. Forty patients with at least three similar-sized non-carious cervical lesions participated in this study. A total of 120 restorations with Prime & Bond NT were placed, 40 in each group. The adhesive was applied with no rubbing action, with slight rubbing action, or with vigorous rubbing action. The restorations were placed incrementally using the composite resin Esthet-X. The restorations were evaluated at baseline and after 6, 12, and 24 months following the modified United States Public Health Service criteria. Statistical analysis was conducted using Friedman repeated measures analysis of variance by rank and using the Wilcoxon signed-rank test for significance at each pair (α = 0.05). The 24-month retention rates of Prime & Bond NT were 82.5% for the no rubbing group, 82.5% for the slight rubbing group, and 92.5% for vigorous rubbing group. No significant difference in the retention rates in each recall period was detected among groups (p > 0.05); however, the retention rates in the 24-month recall was statistically lower than the baseline only for no rubbing or slight rubbing groups. The use of a vigorous application mode can be a clinical approach to improve the retention of restorations placed in non-carious cervical lesions.

Three-year clinical evaluation of endodontically treated anterior teeth restored with a polyethylene fibre-reinforced composite

BACKGROUND

Polyethylene fibre-reinforced composites (FRCs) have been under development for some time. However, there is a lack of data on the clinical performance of these restorations. The purpose of this descriptive study was to evaluate the clinical performance of endodontically treated anterior teeth restored using polyethylene FRCs.

METHODS

Eighty-seven endodontically treated anterior teeth in 65 patients were restored with polyethylene FRCs. The restorations were placed by three operators. The patients were recalled for examinations every year for up to three years. The restorations were evaluated using modified Ryge and USPHS criteria.

RESULTS

A statistical analysis showed no significant difference in marginal irregularity, marginal discolouration, surface texture, wear/anatomic form, fracture and retention, radiographic appearance, or debonding between the baseline and three-year results.

CONCLUSIONS

Based on our three-year examination results, polyethylene FRC restorations appear to be clinically successful.

Effect of filler ratio in adhesive systems on the shear bond strength of resin composite to porcelains

This in vitro study evaluated the effect of six different adhesive systems on the shear bond strength of resin composite to feldspathic and low-fusing porcelains. Sixty porcelain blocks were prepared for each low-fusing (Matchmaker) and feldspathic (MVK95) porcelain specimen. After surface preparation, the porcelain specimens were divided into six groups (n = 10) for different adhesive systems (Adper Prompt L-Pop, QuadrantUnil Bond, Te-Econom, PQ1, One-StepPlus and Prime&Bond NT). After adhesive application, a universal resin composite (FiltekZ250) was condensed on the specimens. The prepared specimens were then stored in distilled water at 37 degrees C for 24 hours, then all the samples were thermal cycled 1000 times between 5 degrees C and 55 degrees C. Shear testing was performed on a universal test machine using a crosshead speed of 0.5 mm/minute. The statistical analysis of the bond strength data included two-way ANOVA. Then, the means were compared by Tukey HSD test (alpha = 0.05). The lowest bond strength was observed in Adper Prompt L-Pop. No statistically significant difference was observed between One-Step Plus and Prime&Bond NT. The highest bond strength was observed in PQ1. When low-fusing or feldspathic porcelain restorations are repaired with resin composite, self-etching adhesive systems may not be indicated. If maximum bond strength is the goal in porcelain resin bonding, adhesive systems that have a high filler ratio should be used.

Clinical Evaluation of a Two-step Etch&Rinse and a Two-step Self-etch Adhesive System in Class II Restorations: Two-year Results

The two-step etch&rinse and the two-step self-etch adhesive systems tested in this study demonstrated similar clinical performance in Class II cavities after two years.

Modified matrix band design for ultra-conservative posterior restorations

Conventional box preparations, tunnel cavities and slot preparations have been recommended for the treatment of proximal carious lesions over the years. If the adjacent tooth is missing or the proximal surface becomes accessible at the time of cavity preparation of the adjacent tooth, a direct proximal access to the decay process can be performed. A similar procedure is supported by the use of adhesive composite restorations reinforcing the remaining sound tooth structure. The increasing patient and clinician's desire for ultraconservative treatment justifies this minimally invasive tooth preparation approach; however, appropriate materials and techniques need to be selected to achieve adequate bonding of the cavity walls and marginal adaptation of the composite.

Influence of solvent type in experimental dentin primer on the marginal adaptation of Class V restorations

OBJECTIVES

The purpose of this in vitro investigation was to evaluate the influence of the solvent type in two experimental dentin primers (ExP) on the handling sensitivity by determining the marginal adaptation of mixed Class V restorations.

METHODS

Standardized cavities were prepared in 32 extracted human molars and randomly assigned to four test groups (n=8). After etching, a three-step adhesive was applied using two ExP which only differed in the type of solvent (acetone/water=ExP-A versus ethanol/water=ExP-E). For ExP-A, the drying procedure (blot-drying versus 2s air drying) prior to primer application was varied, whereas evaporation time (2-3s versus 10s) after primer application was varied for ExP-E. An adhesive was added prior to application of the filling material. Specimens were thermocycled (TC: 2500 cycles; 5-55 degrees C). The length of gap-free margin (LoGfM) was assessed by SEM using replica technique. Data were subjected to non-parametric statistics (p=0.05) as well as the Levene test (p=0.05).

RESULTS

Blot-drying significantly increased the LoGfM after TC for ExP-A in dentin (p<0.05) but decreased LoGfM in enamel (p<0.05). Short evaporation (2-3s) of solvent reduced LoGfM when using ExP-E and led to a significant increase in variances (p<0.05).

CONCLUSIONS

The use of three-step adhesives with ethanol/water-based solvent is recommended due to a lower technique sensitivity versus acetone/water-based systems. Also when using modern ethanol/water-based three-step adhesives, evaporation of primer solvent remains a critical step regarding the marginal quality of the restorations and consequently has to be carried out thoroughly.

Bond strength of different adhesive systems to dental hard tissues

This study compared the shear bond strengths of different adhesive systems to enamel and dentin of different depths. The adhesive systems used were: Single Bond one-bottle total-etch; AQ Bond one-step self-etching, Clearfil SE Bond two-step self-etching and Tyrian SPE/One-step Plus two-step self-etching. Eighty extracted non-carious human mandibular molars were mounted in self-curing resin and the occlusal surfaces were ground with a mechanical grinder to obtain flat occlusal enamel surfaces. After applying the adhesive systems, a plastic tube was attached to the enamel surfaces. The tube was filled with a universal hybrid resin composite, which was then polymerized. The specimens were stored in water at 37 degrees C for 24 hours. Shear bond testing was carried out using an Instron Universal testing machine with a crosshead speed of 1 mm/minute. The occlusal enamel of the 80 teeth was removed to determine the bond strengths of the adhesives to superficial dentin. To obtain deep dentin, the same teeth were ground deep towards the pulp, with the remaining dentin thickness approximately 0.7 mm. The adhesives and restorative material were then applied to the prepared dentin surfaces following the methodology described above. For occlusal enamel surfaces, the bond strength of Single Bond was significantly higher than the other adhesives. Single Bond, Clearfil SE Bond and Tyrian SPE/One-step Plus performed equally when bonded to superficial dentin; the lowest bond strength was obtained with AQ Bond. On deep dentin, the highest bond strengths were obtained with Clearfil SE Bond. For each adhesive system, shear bond strength to enamel was statistically higher than it was to either superficial or deep dentin. There were no significant differences between shear bond strengths to superficial versus deep dentin, regardless of adhesive.

Restoration interface microleakage using one total-etch and three self-etch adhesives

This study evaluated the efficacy of a total-etch and three self-etch adhesives in reducing microleakage after three months water storage and thermocycling. Thirty freshly extracted caries-free human premolars and molars were used. Class V standardized preparations were performed on the facial and lingual surfaces, with the gingival margin placed 1 mm below the CEJ. The teeth were randomly divided into four groups; Group I: Xeno III one-step self-etch adhesive (Dentsply/Caulk), Group II: Prime & Bond NT total-etch adhesive (Dentsply/Caulk), Group III: i-Bond one-step self-etch adhesive (Heraeus Kulzer) and Group IV: Clearfil SE Bond two-step self-etch adhesive (Kuraray Medical). The teeth were restored using 2 mm increments of shade A2 resin composite (Esthet-X, Dentsply/Caulk). Each layer was cured using the Spectrum 800 curing light (Dentsply/Caulk) for 20 seconds at 600mW/cm2. The teeth were stored in distilled water for 90 days. Samples were thermocycled 500x between 5 degrees C and 55 degrees C with a dwell time of 30 seconds, then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margins under a stereomicroscope at 20x magnification. Dye penetration was scored: 0 = no penetration; 1 = partial dye penetration along the occlusal or gingival wall; 2 = dye penetration along the occlusal or gingival wall; 3 = dye penetration to and along the axial wall. A Mann-Whitney test was used to demonstrate significantly more dye penetration in Group III than in the other groups at both the occlusal and gingival scores (p < 0.0001). When comparing the occlusal and gingival scores for each group, the Wilcoxon Rank test showed no significant difference in dye penetration for Xeno III (p > 0.05), Prime & Bond NT (p = 0.059) and I Bond (p = 0.083), and Clearfil SE Bond yielded more dye penetration at the occlusal than at the gingival wall (p = 0.001).

Influence of enamel border and regional variability on durability of resin-dentin bonds

OBJECTIVES

To evaluate the influence of enamel border on regional resin-dentin microtensile bond strength (muTBS) over time.

METHODS

Thirty human third molars had a flat dentine surface exposed. Two adhesive systems (Single Bond [SB] and ScotchBond Multi Purpose Plus [SBMP]) were applied and composite resin crowns (Filtek Z250) were constructed. Teeth were divided into three groups (n=5). Group A, specimens were sectioned to obtain sticks to be tested in tension (0.5mm/min) immediately. Group B specimens were stored without outer enamel in water for 6 months, before sectioning and testing. Group C, specimens were stored with outer enamel in water for 6 months, before sectioning and testing. In all groups, the origin of the sticks, periphery and inner regions was controlled. The data for each adhesive were subjected to a two-way repeated measure ANOVA (location versus storage conditions) and Tukey's test.

RESULTS

No significant degradation in muTBS was observed for SBMU in all conditions. For SB, a significant reduction on muTBS was observed in the specimens without enamel border (group B). The degradation was more pronounced in the specimens from the periphery.

CONCLUSIONS

The three-step etch-and-rinse system is less susceptible to water degradation effects; stable resin-dentin bonds can be achieved with two-step etch-and-rinse systems as long as there is a bonded enamel border.

Microleakage after thermocycling of 4 etch and rinse and 3 self-etch adhesives with and without a flowable composite lining

This study evaluated the microleakage of composite fillings prepared with 4 etch and rinse and 3 self-etch adhesive systems after thermocycling. Also evaluated was the potential improvement of cavity sealing when utilizing a low charged resin lining for cavity preparations. Seventy recently extracted teeth were randomly allocated to 7 experimental adhesive systems: two 3-step etch and rinse adhesive systems, Scotchbond Multipurpose (SBMP) and Optibond Solo Plus (OS); two 2-step etch and rinse adhesive systems, referred to as "one-bottle," Scotchbond 1 (SB1) and Gluma Comfort Bond + Desensitizer (G); and 3 self-etch "all-in-one" adhesives, Adper Prompt-L-Pop (PLP), Xeno III (X-III) and iBond (iB). On each tooth, 2 rectangular cavities were prepared at the cemento-enamel junction: 1 cavity was prepared with adhesive and the hybrid composite and the second was filled with the same adhesive and a thin layer of flowable composite (Filtek Flow) under the resin composite (Z100). All teeth were thermocycled for 800 cycles (5 degrees C-55 degrees C, 30 seconds dwell time). Leakage was evaluated on a 6-point (0-5) severity scale for enamel and dentin on 4 interfaces for each restoration. The results are expressed as means +/- standard deviation (SD). Microleakage scores were analyzed by means of generalized linear mixed models (GLMM), assuming an ordinal logistic link function. Covariates in the model were: (1) adhesives, (2) fluid composite and (3) interface. The model also accounts for repeated measurements on the various teeth. The authors found that the mean score of microleakage per tooth was significantly higher at the enamel rather than at the dentin interfaces (1.21 +/- 0.51 and 0.87 +/- 0.48; p<0.0001). In this study, there was no significant difference among the 4 etch and rinse adhesive systems. On the other hand, these adhesives yielded smaller mean scores of microleakage than the 3 self-etch systems (respectively, 0.85 +/- 0.2 and 1.3 +/- 0.5; p<0.0001). Among the self-etch adhesives, microleakage was significantly greater for PLP (1.74 +/- 0.46) than for the other self-etch products (p<0.0001), while X-III, an intermediary strong self-etch, was found to be as good as the etch and rinse systems, with a mean score of 0.97 +/- 0.27. In addition, results have also shown that an under layer of flowable composite significantly improved the water tightness of the PLP adhesive restorations (p=0.042). This in vitro study concluded that the self-etch adhesives remain less effective than etch and rinse. Nevertheless, X-III, a self-etch adhesive, showed acceptable performance in accordance with this study's 6-point severity scale of microleakage, but this needs to be confirmed in further clinical studies. On the other hand, this study failed to reveal that the addition of a thin layer of fluid composite improved the water tightness of the restoration, except for PLP.

Direct cuspal-coverage posterior resin composite restorations: A case report

The clinical success of direct composite restorations is the result of the correct use and performance of adhesive systems, resin composites and light curing systems. Total-etch adhesive systems and microhybrid resin composites have seen continuous improvement; various clinical techniques have been introduced to address polymerization shrinkage. Manufacturers have introduced sophisticated light-curing devices with the hope of improving performance. Direct resin bonded composites (RBCs) are becoming the first choice in many clinical situations. This article presents an experimental clinical technique that outlines the reconstruction of severely damaged posterior teeth missing multiple cusps; particular attention to incremental and curing techniques is adopted to complete each restoration.

Microtensile bond strength of a filled vs unfilled adhesive to dentin using self-etch and total-etch technique

OBJECTIVE

The purpose of this study was to evaluate the effect of a filled adhesive (One-Step Plus; Bisco) versus an unfilled adhesive (One-Step; Bisco) on the microtensile bond strength (muTBS) to dentin using total-etch (Uni-etch; Bisco) and self-etch (Tyrian SPE; Bisco) techniques.

METHODS

Twenty extracted human third molars were ground flat to expose occlusal dentin. After the dentin surfaces were polished with 600-grit SiC paper, the teeth were randomly assigned to four groups according to the bonding agent and technique being used. Dentin surfaces were bonded with One-Step Plus+total-etch; One-Step Plus+self-etch; One-Step+total-etch and One-Step+self-etch. Composite buildups were performed with Clearfil AP-X (Kuraray Medical). Following storage in distilled water at 37 degrees C for 24 h, the bonded specimens were serially sectioned into 0.7 mm-thick slabs and then trimmed to hour-glass shapes with a 1 mm2 cross-sectional area (n=20). Microtensile bond strengths were determined using the EZ-test (Shimadzu) at a cross-head speed of 1 mm/min. Data were analyzed using two-way ANOVA and Tukey's post hoc test.

RESULTS

There were no significant differences in the muTBS between One-Step Plus and One-Step adhesives when they were used with the total-etch and self-etch techniques (p>0.05). However with the total-etch technique both adhesives yielded significantly higher bond strength values than the self-etch technique (p<0.001).

CONCLUSION

The filled adhesive One-Step Plus did not show any beneficial effect than the unfilled adhesive One-Step on the muTBS to dentin with total-etch and self-etch techniques. Irrespective from the adhesive type, self-etch technique revealed lower bond strengths than the total-etch technique.

Five-year clinical evaluation of two adhesive systems in non-carious cervical lesions

OBJECTIVE

This controlled clinical trial evaluated the 5-year clinical performance of a self-etching primer system including selective enamel-etching with phosphoric acid and a one-bottle adhesive system.

METHODS

Seventy-two non-carious cervical lesions in 8 patients (4 male and 4 female) with a mean age of 61.3 years (range 45-78) participated in the study. An enamel bevel was placed and dentin lightly ground, and cavities restored with clearfil liner bond II (LB) or single bond (SB) in conjunction with a hybrid resin composite (Clearfil AP-X). In the case of 27 cavities for LB, the enamel was pretreated with 37% phosphoric acid for 10 s. Each patient received both types of restoration, which were distributed on a random basis. All restorations (37 restorations for LB and 35 restorations for SB) were placed by one dentist. The restorations were evaluated blind after 5 years using modified USPHS criteria. The data were statistically analyzed using the Fisher's exact test.

RESULTS

All but one restoration (which was replaced by a crown after the 2-year recall) were evaluated after 5 years. 100% retention rates were recorded for both restorative groups. No caries was detected in association with any restorations. The only minor problem was marginal discoloration; superficial and localized marginal discoloration occurred around 18% of the restorations, and mainly at the dentin margin. There were no significant differences in the marginal integrity between the LB and SB groups.

CONCLUSIONS

Restorative materials used in this study demonstrated a good clinical effectiveness in the restoration of non-carious cervical lesions for 5 years.

Two-Year Clinical Evaluation of Nonvital Tooth Whitening and Resin Composite Restorations

BACKGROUND

Adhesive systems, resin composites, and light curing systems underwent continuous improvement in the past decade. The number of patients asking for ultraconservative treatments is increasing; clinicians are starting to reevaluate the dogma of traditional restorative dentistry and look for alternative methods to build up severely destroyed teeth.

PURPOSE

The purpose of this study was to evaluate the efficacy of nonvital tooth whitening and the clinical performance of direct composite restorations used to reconstruct extensive restorations on endodontically bleached teeth.

MATERIALS AND METHODS

Twenty-one patients 18 years or older were included in this clinical trial, and 26 endodontically treated and bleached maxillary and mandibular teeth were restored using a microhybrid resin composite. Patients with severe internal (tetracycline stains) and external discoloration (fluorosis), smokers, and pregnant and nursing women were excluded from the study. Only patients with A3 or darker shades were included. Teeth having endodontic access opening only to be restored were excluded; conversely, teeth having a combination of endodontic access and Class III/IV cavities were included in the study. A Vita shade guide (Vita Zahnfabrik, Bad Säckingen, Germany) arranged by value order was used to record the shade for each patient. Temporary or existing restorations were removed, along with a 1 mm gutta-percha below the cementoenamel junction (CEJ), and a resin-modified glass ionomer barrier was placed at the CEJ. Bleaching treatment was performed using a combination of in-office (OpalescenceXtra, Ultradent Products, South Jordan, UT, USA) and at-home (Opalescence 10% PF, Ultradent Products) applications. Two weeks after completion of the bleaching, the teeth were restored using a combination of PQ1 adhesive system and Vit-l-escence microhybrid resin composite (Ultradent Products). Wedge-shaped increments were placed and cured using the VIP Light (Bisco, Inc Schaumburg, IL, USA) through a combination of pulse and progressive curing techniques.

RESULTS

All but one restoration were evaluated by two independent evaluators every 6 months during a 2-year period using modified US Public Health Service criteria. No restoration failed and "alpha" scores were recorded for all parameters but color stability, which was scored "bravo." Analysis of variance showed a significant shade change between baseline (mean=14.4+/-1.9) versus 2 weeks (mean=1.6+/-0.7) and 2 years (mean=2.8+/-1.7) (p<.0001). Although a significant shade change was observed between 2 weeks and the 2-year follow-up (p=.008), no significant difference was reported between the baseline and 2 weeks (12.9+/-2) versus baseline and 2 years (11.9+/-2.3).

CONCLUSIONS

Significant tooth lightening was reported after the completion of whitening therapy on devitalized teeth; shade rebound was reported in less than 50% of the treated teeth and was limited to a maximum of four shades. A microhybrid resin composite demonstrated excellent clinical performance in the restoration of all endodontically treated and bleached teeth after a 2-year evaluation period.

CLINICAL SIGNIFICANCE

Nonvital tooth whitening is responsible for a significant change in color of endodontically stained teeth. Successful nonvital tooth-whitening therapy allows for conservative tooth preparation, preserving and reinforcing sound tooth structure. The proper use of modern adhesive systems along with resin composite restorations precludes the use of more extensive restorative treatment, delaying expensive crown and bridge procedures.

Influence of specimen size and regional variation on long-term resin–dentin bond strength

OBJECTIVES

Verify whether the dimension of a bonded specimen stored prior microtensile testing and its regional variation may affect the resin-dentin bond strength (BS) over time.

METHODS

Thirty human third molars had a flat dentin surface exposed and all peripheral enamel removed. Two adhesive systems (Single-Bond and One-Step) were applied and composite resin crowns (Z250) were constructed. Teeth were divided into three groups (n = 5). Group A specimens were sectioned to obtain sticks to be tested in tension (0.5 mm/min) immediately. Group B specimens were stored in water for 6 months, before sectioning and testing. Group C specimens were sectioned; the sticks were stored for 6 months and tested. In groups A and B, the origin of the sticks, periphery and inner regions was controlled. Bond strength (BS) was expressed as an index that considers cohesive failures and estimated values of premature debonded specimens. One-way ANOVA and Tukey's test (alpha = 0.05) were used to compare groups A, B and C, and a second analytical approach (A and B) employed a two-way ANOVA (time versus regional differences) for each adhesive system.

RESULTS

For Single-Bond (SB), the BS for specimens in group A was higher than for groups B and C. For One-Step (OS), the BS in group A was higher than for B, which was in turn higher than for C. In the second group approach, no difference was found when the test was performed immediately; however, after 6 months, the inner sticks from group B showed significantly higher BS.

SIGNIFICANCE

(1) The amount of decrease in BS is dependent on the specimen size; (2) the decrease in BS was greater for peripheral specimens than more centrally located specimens.

Effect of dentine conditioners on the bonding efficacy of one-bottle adhesives

The bonding efficacy of four one-bottle adhesives (OptiBond Solo Plus, Gluma Comfort Bond, One Step and Prime & Bond NT) and a multi-step adhesive (Clearfil Photo Bond) as a control was evaluated. The dentine cavity wall was conditioned with phosphoric acid or ethylenediaminetetraacetic acid (EDTA) and the marginal integrity was estimated by measuring the wall-to-wall contraction gap width between the composite and the dentine cavity surface. In the positive control group, the adhesive was applied following glyceryl methacrylate (GM) priming. The analyses were performed by Kruskal-Wallis and Mann-Whitney U-tests. One-bottle adhesives were clearly inferior to the multi-step bonding system in marginal integrity when dentine was conditioned with EDTA. The present findings also suggested that the marginal sealing ability of ethanol-based one-bottle systems was better than acetone-based one-bottle systems when dentine surfaces were conditioned with EDTA. Nevertheless, further investigations are needed on the function of fillers in one-bottle adhesives for the prevention of contraction gaps.

Clinical evaluation of a self-etching and a one-bottle adhesive system at two years

OBJECTIVES

The clinical performances of a self-etching adhesive system, Clearfil SE Bond, and a one-bottle adhesive system, Prime&Bond NT, were evaluated in non-carious Class V restorations for a period of two years.

METHODS

Ninety-eight restorations were made by one operator for 32 patients. The resin composite used to restore the teeth were Clearfil AP-X and Spectrum TPH for Clearfil SE Bond and Prime&Bond NT, respectively. Two clinicians at the baseline, 6th, 12th and 24th months evaluated the posterior composites according to the modified Ryge criteria's. For this, color match, marginal discoloration, marginal adaptation, recurrent caries, anatomic form, postoperative sensitivity and retention rates were considered. The changes across time and across groups were evaluated statistically.

RESULTS

At two years, 88 restorations were reviewed in 28 patients. The retention rates for Clearfil SE Bond were 93 and 91% for Prime&Bond NT. The percentages of the retention rates of both adhesive systems were not found to be different when calculating the failure rates. Recurrent caries, anatomic form and postoperative sensitivity were scored as Alpha for all restorations. Two cases of both adhesive systems showed slight marginal discoloration problems. Three restorations of Prime&Bond NT and one of Clearfil SE Bond had marginal adaptation problems at two years. One case for each adhesive system had slight color change after the same period.

CONCLUSION

We can conclude that both adhesive systems tested exhibited very good clinical performance at the end of two years.