Clinical evaluation of packable and conventional hybrid posterior resin-based composites

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.

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.

Adaptation Assessment of Three Bonded Resin Restorations at the Cavity Floor Using Cross-Polarization Optical Coherence Tomography

Objective: The aim of the study was to compare the composite adaptation of three systems by using cross-polarization optical coherence tomography (CP-OCT). Background data: Most polymer-based restorations suffer from polymerization shrinkage that affects the interfacial seal. This shrinkage cannot be detected by conventional X-ray methods. Optical coherence tomography was proved to be a reliable non-invasive imaging tool to examine biological structures and biomaterials at micron scale. Methods: Twenty-four cylindrical class-V cavities were prepared on the buccal surfaces of the extracted human molars. After cavity preparation, samples were randomly divided into three groups (n = 8) according to the restoration system: one-step self-etch Clearfil Tri-S Bond Plus with Clearfil Majesty ES-2 composite (TS; Kuraray Noritake Dental), Single Bond Universal in self-etch mode with Filtek Z350 XT composite (SB; 3M ESPE), and one-step self-etch Plafique Bond with Plafique LX 5 composite (PB; Tokuyama Dental). The restoration placement was carried out according to the manufacturers' recommendations. Later, the specimens were immersed in a contrasting agent; then, image acquisitions were taken by CP-OCT to calculate the adaptation percentage by using an image analysis software. Results: Mann-Whitney U test showed no statistical significant difference in the adaptation percentage between TS (91.72 ± 11.6) and SB (93.43 ± 6.9) groups (p > 0.05). However, the adaptation percentage in PB (41.83 ± 28.5) was significantly lower than in the other tested groups (p < 0.05). Conclusions: Within the limitation of the study, TS and SB groups showed better adaptation than PB. Moreover, CP-OCT is a useful imaging tool that can display composite adaptation at micron scale.

Clinical Behaviour and Marginal Sealing of Bulk-Fill Resin Composite Restorations Using Light Amplified High-Intensity LEDs Curing: A Randomized Controlled Clinical Trial

BACKGROUND:

Delivering sufficient intensity output of curing lights is mandatory to ensure optimum cure and clinical success of bulk-fill resin composite restorations and to avoid undesirable clinical outcomes.

AIM:

To evaluate the effectiveness of using light amplified high intensity LED curing on the clinical performance and marginal sealing of posterior bulk-fill resin composite restorations.

MATERIAL AND METHODS:

This study was designed as a randomised, controlled, double-blind, Unicenter, parallel, two arms, superiority trial with 1:1 allocation ratio. Adult patients who required posterior tooth-coloured restorations were asked to participate in this trial. All participants signed written informed consent after being completely aware of the settings of the study. The participants who fulfilled the eligibility criteria were divided into two groups according to the type of light curing mode used. Adhesive compound proximal cavities were prepared. All restorative materials were applied according to the respective manufacturer’s instructions. Assessments of the restorations were done at baseline (one week after placement of the restoration), after 6 months and after 12 months using the modified US Public Health Service (USPHS) criteria. For quantitative assessment of the marginal sealing, resin replicas were analysed using scanning electron microscopy. Statistical analysis was done using Chi-square, Mann Whitney, independent t-test and dependent t-tests.

RESULTS:

There were no statistical differences between the two groups for the tested clinical parameters along the study periods. For marginal analysis, there were no statistical differences between the intervention and control group at baseline and six months (p-value = 0.347 and 0.516) respectively. At 12 months the control group showed statistically significant higher percentages (p-value = 0.031).

CONCLUSION:

Light amplified high-intensity curing units have clinical performance comparable with the conventional LED.

One-year clinical evaluation of different types of bulk-fill composites

AIM

In the present study, we evaluated the 1-year clinical performance of a conventional posterior composite resin and three bulk-fill composite resins.

METHODS

Fifty patients with four class II restorations under occlusion were enrolled in the present study. A total of 200 restorations were placed in the cavity, 50 for each material (Clearfil Photo Posterior, Filtek Bulk-Fill Flowable and Filtek P60, Tetric EvoCeram Bulk-Fill, and SonicFill). One operator placed the restorations in the cavity, and 1 week later the patients were called for baseline examination. Two calibrated examiners evaluated the restorations once every 3 months for 1 year, according to United States Public Health Service criteria. The data were analyzed using SPSS. Non-parametric tests (Kruskal-Wallis, Mann-Whitney U-test, and Friedman) were used for the analysis at a confidence level of 95%.

RESULTS

The 1-year recall rate was 86%. All restorations showed minor modifications after 1 year. However, no statistically-significant differences were detected between the materials' performance at baseline and after 1 year for all criteria (P > 0.05).

CONCLUSIONS

The bulk-fill composite resin materials showed similar clinical performance when compared with a conventional posterior composite resin. Further evaluations are necessary for the long-term clinical performance of these materials.

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.

A 6-year prospective evaluation of a one-step HEMA-free self-etching adhesive in Class II restorations

OBJECTIVE

The aim of this study was to evaluate the clinical effectiveness of a one-step HEMA-free self-etching adhesive (SEA) placed with a micro-fine hybrid resin composite in Class II restorations. The restorations were compared intraindividually with 2-step HEMA containing SEA-giomer restorations.

MATERIAL AND METHODS

Fifty-four patients with at least one pair of two similar Class II cavities participated (30 men, 24 women; mean age 57.1yrs). A total of 115 Class II composite restorations were placed with (1) a one step HEMA-free adhesive and a micro-fine hybrid resin composite (Gbond/Gradia Direct: 60; GG) and (2) a 2-step HEMA-containing SEA and a giomer (FL Bond/Beautifil: 55; FB). Each participant received in a randomized way at least one restoration with each of the experimental materials. The restorations were evaluated at baseline and yearly during a 6 year followup using modified USPHS criteria.

RESULTS

During the 6 years, 111 restorations could be evaluated. No post-operative sensitivity was reported by the participants. Fourteen failed restorations (12.6%) were observed during the follow up, 5 GG (8.5%; 4 premolar and 1 molar teeth) and 9 FB (17.7%; 1 premolar and 8 molar teeth) (p<0.05). Annual failure rate at 6 years were 1.4% for GB and 3.0% for FB. Main reasons of failure were bulk fracture of resin composite for FB and tooth fracture for GB.

SIGNIFICANCE

The HEMA-free SEA-hybrid RC restorations showed good clinical durability in Class II cavities after 6 years. The HEMA-containing SEA-giomer restorations showed a rather high failure frequency.

Clinical performance of ormocer, nanofilled, and nanoceramic resin composites in Class I and Class II restorations: a three-year evaluation

PURPOSE

This prospective long-term clinical trial evaluated and compared the three-year clinical performance of an ormocer, a nanofilled, and a nanoceramic resin composite with that of a microhybrid composite placed in Class I and Class II cavities.

METHODS

Forty patients, each with four Class I and II restorations under occlusion, were enrolled in this study. A total of 160 restorations were placed, 25% for each material, as follows: an ormocer-based composite, Admira; a nanofilled resin composite, Filtek Supreme XT; a nanoceramic resin composite, Ceram X; and a microhybrid resin composite, Tetric Ceram. A single operator placed all restorations according to the manufacturers' instructions. Immediately after placement the restorations were finished/polished. Clinical evaluation was performed at baseline and at yearly intervals after placement by two other independent examiners using modified US Public Health Service (USPHS) criteria. The changes in the USPHS parameters during the three-year period were analyzed with the Friedman test. Comparison of the baseline scores with those at the recall visits was made using the Wilcoxon signed rank test. The level of significance was set at p < 0.05.

RESULTS

All materials showed only minor changes, and no differences were detected between their performance at baseline and after three years. Only two ormocer, one nanofilled, and one microhybrid restorations in molars failed because of loss of retention. Regarding the clinical performance, there were no statistically significant differences among the materials used (p>0.05).

CONCLUSIONS

The ormocer, nanofilled, and nanoceramic composites provided acceptable clinical performance over a three-year period.

Prediction and diagnosis of clinical outcomes affecting restoration margins

The longevity of dental restorations is largely dependent on the continuity at the interface between the restorative material and adjacent tooth structure (the restoration margin). Clinical decisions on restoration repair or replacement are usually based upon the weakest point along that margin interface. Physical properties of a restorative material, such as polymerisation shrinkage, water sorption, solubility, elastic modulus and shear strength, all have an effect on stress distribution and can significantly affect margin integrity. This review will focus on two aspects of margin deterioration in the oral environment: the in vitro testing of margin seal using emersion techniques to simulate the oral environment and to predict clinical margin failure and the relationship between clinically observable microleakage and secondary caries. The many variables associated with in vitro testing of marginal leakage and the interpretation of the data are presented in detail. The most recent studies of marginal leakage mirror earlier methodology and lack validity and reliability. The lack of standardised testing procedures makes it impossible to compare studies or to predict the clinical performance of adhesive materials. Continual repeated in vitro studies contribute little to the science in this area. Clinical evidence is cited to refute earlier conclusions that clinical microleakage (penetrating margin discoloration) leads to caries development and is an indication for restoration replacement. Margin defects, without visible evidence of soft dentin on the wall or base of the defect, should be monitored, repaired or resealed, in lieu of total restoration replacement.

Clinical performance of a nanofilled resin composite with and without an intermediary layer of flowable composite: a 2-year evaluation

The objective of this prospective clinical follow-up was to evaluate the 2-year clinical performance of a nanofilled resin composite in class II restorations. The restorations were made with and without intermediary layer of a nanofilled flowable resin composite studied in an intraindividual comparison. Each participant received at least two, as similar as possible, class II restorations of the nanofilled resin composite. One restoration of each pair (54) was chosen at random to be restored with an intermediary layer with flowable nanofilled resin composite. The other was restored without. The restorations were evaluated with slightly modified US Public Health Services criteria at baseline, 1, and 2 years. Ninety-two restorations, 46 pairs, were evaluated at 2 years. A prediction of the caries risk showed that 22 of the evaluated 48 patients were considered as high-risk patients. Two failures were observed, one in each group, resulting in a 2.2% failure rate. No statistical difference was seen between the restorations restored with and without layer of flowable resin composite. The nanofilled resin composite showed very good surface characteristics and color match, which did not change significantly during the follow-up period. The nanofilled resin composite showed a good clinical performance with a 2.2% failure rate after 2 years. No differences were observed between the restorations with and without the nanofilled flowable resin intermediary layer.

Clinical performance of a hybrid resin composite with and without an intermediate layer of flowable resin composite: a 7-year evaluation

OBJECTIVE

The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite.

METHODS

Each participant received at least two, as similar as possible, Class II restorations of the hybrid resin composite. One resin composite restoration of each pair (59) was chosen at random to be restored with an intermediary layer with flowable resin composite. The other was restored without. The 118 restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 7 years.

RESULTS

Four drop outs were registered during the 7-year follow up (2 with and 2 without flowable) restorations. A prediction of the caries risk showed that 18 of the evaluated 46 patients were considered as high risk patients. Seventeen failures were observed, 8 in restorations with and 9 in restorations without an intermediate layer of flowable resin composite, resulting in a 14.9% failure rate after 7 years. The main reasons for failure were: fracture of resin composite (8), secondary caries (4) and cusp fracture (3). No statistical difference was seen between restorations restored with and without flowable layer.

CONCLUSION

The hybrid resin composite showed a good clinical performance during the 7-year evaluation. The use of flowable resin composite as an intermediate layer did not result in improved effectiveness of the Class II restorations.

Eighteen-month clinical evaluation of microhybrid, packable and nanofilled resin composites in Class I restorations

The aim of this article was to report the results of an 18-month longitudinal randomized clinical trial that evaluated the clinical performance of microhybrid, packable and nanofilled resin composite restorations placed in Class I cavities of molar teeth. Three Class I resin composite restorations were placed in each of 35 patients. Each patient received one microhybrid ('Point 4'; Kerr, Orange, CA, USA), one packable ('Packable Premise'; Kerr, Orange, CA, USA) and one nanofilled ('Nanofilled Premise'; Kerr, Orange, CA, USA) resin composite restoration. Clinical evaluation was performed at baseline (2 weeks after placement), and after 6, 12 and 18 months after placement using modified Ryge criteria. No patients were lost from the study. At the final appointment (after 18 months), 95.4%, 93.7% and 96.2% respectively of the microhybrid ('Point 4'), packable ('Packable Premise' and nanofilled ('Nanofilled Premise') resin composite restorations received Alfa ratings. Regardless of the type of restorative material, no significant changes were observed in the modified Ryge criteria at the baseline and 18-month recalls (P <or=0.05). Three restorations (one from each group) exhibited post-operative sensitivity at the baseline and 6-month appointment. After 18 months, one packable resin composite restoration failed because of secondary caries, while secondary caries was not detected on any of the other restorations. The clinical performance of microhybrid ('Point 4'), packable ('Packable Premise') and nanofilled ('Nanofilled Premise') resin composite restorations was acceptable after 18 months. Further studies with longer follow-up periods are recommended to investigate the long-term survival of these restorations.

Evaluation of Packable and Conventional Hybrid Resin Composites in Class I Restorations: Three-year Results of a Randomized, Double-blind and Controlled Clinical Trial

Long-term randomized, controlled, clinical trials of treatment outcomes are clearly needed to evaluate the long-term performance of composites in posterior teeth.

Two years survival rate of class II composite resin restorations prepared by ART with and without a chemomechanical caries removal gel in primary molars

The aim was to test the null hypotheses that there is no difference: (1) in carious lesion development at the restoration margin between class II composite resin restorations in primary molars produced through the atraumatic restorative treatment (ART) with and without a chemomechanical caries removal gel and (2) in the survival rate of class II composite resin restorations between two treatment groups after 2 years. Three hundred twenty-seven children with 568 class II cavitated lesions were included in a parallel mouth study design. Four operators placed resin composite (Filtek Z 250) restorations bonded with a self-etch adhesive (Adper prompt L pop). Two independent examiners evaluated the restorations after 0.5, 1, and 2 years using the modified Ryge criteria. The Kaplan-Meier survival method was applied to estimate survival percentages. A high proportion of restorations were lost during the study period. Therefore, the first hypothesis could not be tested. No statistically significant difference was observed between the cumulative survival percentages of restorations produced by the two treatment approaches over the 2-year period (ART, 54.1 +/- 3.4%; ART with Carisolv, 46.0 +/- 3.4%). This hypothesis was accepted. ART with chemomechanical gel might not provide an added benefit increasing the survival percentages of ART class II composite resin restorations in primary teeth.

Alignment of transposed mandibular lateral incisor and canine using removable appliances

The purpose of this paper was to present the management of a rarely encountered transposition anomaly involving the mandibular permanent lateral incisor and the canine. In the literature, the treatment of this type of anomaly involves fixed orthodontic appliances. The treatment of the present case, however, was performed with removable appliances. Transposition of the permanent mandibular right lateral incisor and the permanent mandibular right canine was detected in a 12 year old girl. The primary mandibular right canine was extracted to enable the distal movement of the permanent lateral incisor by the eruption force of the permanent canine. The transposed teeth were then aligned in the arch by using removable appliances. The forms of the teeth were changed with each other with composite restorations.

Six-year Clinical Evaluation of Packable Composite Restorations

As a posterior composite, Filtek P60 exhibited very good clinical performance in Class II cavities for six years.

Degradation, fatigue, and failure of resin dental composite materials

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

Effect of restoration size on the clinical performance of posterior "packable" resin composites over 18 months

Fifty predominantly moderate or large Class II or multiple-surface Class I resin composite restorations were placed in molars under rubber dam isolation. The restorative systems used were: Alert Condensable (Jeneric/Pentron) and SureFil (Dentsply/Caulk). The restorations were classified according to size, with 7 small, 25 moderate and 18 large, of which 8 were cusp replacement restorations. Baseline, 6, 12 and 18-month double-blinded clinical evaluations were carried out using modified USPHS criteria. The independent variables: restorative material, restoration size and three other clinical factors, were tested using a Multiple Logistic Regression procedure to determine if any were predictive of failure. Of the 50 restorations, four failed by the 18-month recall, three failed due to fracture of the restoration and one due to secondary caries. Both restorative systems demonstrated a 92% success rate. No association between restoration size (p = 0.99) or restorative material (p = 0.65) and failure was found. Similarly, the additional variables, occlusal contact type, presence of occlusal wear facets and first or second molar, were not predictive of failure.

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

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

Clinical wear of posterior metal-free polymer crowns. One-year results from a randomized clinical trial

OBJECTIVES

The purpose of this randomized clinical trial was to evaluate the clinical wear behavior of posterior, metal-free polymer crowns, with and without a glass-fiber framework, and to compare it with that of metal-ceramic crowns.

METHODS

Eighty single crowns manufactured from a newly designed polymer composite were set in posterior teeth. Half of these received a glass-fiber framework (group 1) whereas half were prepared without framework stabilization (group 2). All polymer crowns were adhesively luted with resin cement. As the control group, 40 conventional metal-ceramic crowns were inserted with hybrid cement. Wear was measured, by use of gypsum replicas, at baseline and after 12 months, by use of a 3D laser scanner. Statistical analysis was performed using mixed-effects regression model analyses.

RESULTS

The mean total wear of posterior single crowns was -8.1 microm (+/-9.7 microm) in group 1, -7.0 microm (+/-9.1 microm) in group 2, and -3.4 microm (+/-6.3 microm) in the control group. Statistical analysis revealed wear behavior was significantly different from the control group for group 1 (p=0.014) and group 2 (p<0.01). No significant difference was detected between groups 1 and 2. Age, gender, and opposing teeth had no significant effect on wear behavior.

CONCLUSIONS

Within a 12-month observation period mean total wear of posterior polymer crowns with and without a glass-fiber framework was significantly greater than for metal-ceramic crowns. The selection of restorative materials should be based on knowledge of clinical wear in order to preserve occlusal stability.

Clinical evaluation of two packable posterior composites: 2-year follow-up

The clinical performance of two packable posterior composites, Alert (A)-Jeneric/Pentron and SureFil (S)-Dentsply, was evaluated in 33 patients. Each patient received one A and one S restoration, resulting in a total of 66 restorations. The restorations were placed by one operator according to the manufacturer's specifications and were finished and polished after 1 week. Photographs were taken at baseline and after 2 years. Two independent evaluators conducted the clinical evaluation by using modified United States Public Health Service criteria. After 2 years, 60 restorations (30 A and 30 S), 27 class I (16 A and 11 S) and 33 class II (14 A and 19 S) were evaluated in 30 patients. Criterion A for recurrent caries, vitality, and retention was applicable to all 60 restorations. Criterion B was distributed among 40 restorations as follows: surface texture (15 A; 2 S), color (5 A; 6 S), postoperative sensitivity (1 S), marginal discoloration (8 A), marginal adaptation (3 A), and wear resistance (2 A). Data were analyzed using the Exact Fisher and McNemar tests. After 2 years, S showed a significantly better performance than A with respect to surface texture and marginal discoloration. The clinical performance of both materials was considered acceptable over the 2-year period. Further evaluations are necessary for a more in-depth analysis.