Quantitative Margin Analysis Research Articles

Effect of the Adhesive Strategy on Clinical Performance and Marginal Integrity of a Universal Adhesive in Non-Carious Cervical Lesions in a Randomized 36-Month Study.

The effectiveness of a universal adhesive applied in three application modes for the preparation of Class V composite restorations was evaluated both clinically and by quantitative marginal analysis (QMA) over 36 months. In 50 patients, three (n = 21) or four (n = 29) non-carious cervical lesions (NCCL) were restored with Venus® Diamond Flow (Kulzer GmbH, Hanau, Germany). The adhesive iBond® Universal (iBU, Kulzer, Germany) was used in self-etch (SE), etch-and-rinse (ER), or selective-enamel-etch mode (SEE). The etch-and-rinse adhesive OptiBondTM FL served as a control (OFL, Kerr GmbH, Herzogenrath, Germany). The restorations were clinically assessed (FDI criteria) at 14 days (BL), 6, 12, 24, and 36 months. Additionally, QMA was conducted on all restorations of 11 randomly selected patients. FDI criteria and marginal gap and perfect margin were compared between and within groups and recalls using McNemar, Wilcoxon, or Mann-Whitney U-tests (α = 0.05). Starting with 12 months, cumulative failure rates were lower in iBU-SE (0.0%, p = 0.016) and iBU-ER groups (2.1%, p = 0.07) compared to OFL (16.7%). At two years, iBU-SEE also showed fewer failures (0.0% SEE vs. 34.6% OFL, p = 0.016), as did iBU-SE compared to iBU-ER after 36 months (2.2 and 19.6%, p = 0.039). From BL, the iBU-SEE group always had the fewest marginal gaps and the highest percentage of perfect margins. From BL, iBU-SEE (0%, p = 0.008) and iBU-ER (0.2%, p = 0.027) showed significantly fewer marginal gaps compared to OFL (2.5%) and more perfect margins were found with iBU-SEE starting at 6 months (p = 0.054). The SEE and ER modes ensured the most excellent marginal quality, with differences from the control appearing earlier with QMA than clinically. In restoring NCCls, iBU showed superior clinical performance over OFL, especially in modes SE and SEE.

Academic research on renewable electricity auctions: Taking stock and looking forward

Auctions are currently the dominant and most rapidly expanding form of support for renewable energy project deployment, capturing the interests of policy-makers and academics alike. This article provides a systematic review of the relatively recent but already abundant literature on auctions for renewable energy and proposes a future research agenda on the topic. Major themes, gaps in knowledge, and trends in the literature are highlighted. More research efforts will be needed on the institutional capacity and arrangements, coordination between auctions and other procedures and appropriate inclusion of auctions in policy mixes. The trade-offs between different criteria should be the focus of more rigorous and quantitative marginal analysis, identifying the extent to which improving a given criterion worsens another. The existence, causes and consequences of underbidding, the implications of the just energy transition for the performance of auctions and auction design, the marginal impact of the level of design elements and the interactions between design element choices in “design element packages” merit more attention. There should be a greater focus on the micro-level in the assessment of the success of auctions and auction design. At a methodological level, assessments of auctions with case studies should coexist with more quantitative studies on the topic, using a wide range of methodologies. However, the transferability of lessons on the functioning of design elements across different contexts will be necessarily limited. Finally, a plea is made to national governments and international institutions to facilitate the access to auction data.

Clinical Outcomes and Quantitative Margin Analysis of a Universal Adhesive Using a Randomized Clinical Trial over Three Years.

The effectiveness of a universal adhesive applied in different application modes for the preparation of Class V composite restorations was evaluated both clinically and by quantitative marginal analysis (QMA). In each of the 22 patients, four non-carious cervical lesions (NCCL) were restored with Filtek™ Supreme XTE (3M). The adhesive Scotchbond™ Universal (SBU, 3M) was applied in self-etch (SE), selective-enamel-etch (SEE) or etch-and-rinse (ER) modes. The etch-and-rinse adhesive OptiBond™ FL (OFL, Kerr) served as a control. The restorations were clinically evaluated (FDI criteria) after 14 days (BL), 6, 12, 24, and 36 months. Additionally, QMA was conducted on all restorations of 11 randomly selected patients. The FDI criteria and marginal gap were statistically compared between the groups at each recall as well as for the time periods between recalls. The cumulative failure rate was non-significantly higher in the OFL group when compared to all of the SBU groups. Marginal adaptation in the OFL and SBU-SE/ER groups was significantly decreased (BL-36 m, p: 0.004) in comparison to the SBU-SEE group (BL-36 m, p: 0.063). More marginal gaps were found in the OFL group than in the SBU-SEE (BL to 36 m, p: 0.063-0.003) and SBU-ER (24/36 m, p: 0.066/0.005) groups as well as in the SBU-SE group when compared to the SBU-SEE (12-36 m, pi ≤ 0.016) and SBU-ER (24/36 m, p: 0.055/0.001) groups. SBU-SEE performed most effectively. The clinical evaluation and QMA corresponded, yet QMA detected group differences earliest after 6 months and is thus a valuable extension to clinical evaluations.

Marginal integrity of classical and bulk-fill composite restorations in permanent and primary molars

Bulk-fill composites enable timesaving and less technical-sensitive application of restorations. This study investigated and compared the marginal integrity of classical and bulk-fill composite restorations in primary and permanent molars before and after thermo-mechanical loading (TML). Two Class II cavities were prepared in each of 20 primary and 20 permanent molars. The molars were randomised in four groups for each molar type. Groups 1 and 5 were restored with a high-viscous bulk-fill composite (Tetric PowerFill), groups 2 and 6 were restored with a flowable bulk-fill composite (Tetric PowerFlow), groups 3 and 7 were restored with a high-viscous classical composite (Tetric Prime), and groups 4 and 8 were restored with a flowable classical composite (Tetric EvoFlow). In permanent molars, the flowable composites were covered with a 2-mm layer of high-viscous composite (groups 6 and 8). The restorations were subjected to TML in a custom-made chewing machine (5–50 °C, 2 min dwelling time, × 1000; 400 ,000 loading cycles, 1.7 Hz, 49 N), and quantitative marginal analysis was conducted using scanning electron microscopy. Marginal integrity of each restoration was calculated as a percentage of continuous margins before and after TML. The tested high-viscous bulk-fill restoration showed similarly high marginal integrity in primary and permanent molars as the classical restoration. The tested flowable bulk-fill restoration showed the lowest marginal integrity compared to all other restorations after TML. In contrast to flowable bulk-fill restorations, high-viscous bulk-fill restorations show similar marginal integrity as classical hybrid composite restorations after TML, in both primary and permanent molars.

Study Protocol PROMETHEUS: Prospective Multicenter Study to Evaluate the Correlation Between Safety Margin and Local Recurrence After Thermal Ablation Using Image Co-registration in Patients with Hepatocellular Carcinoma

PurposeThe primary objective is to determine the minimal ablation margin required to achieve a local recurrence rate of < 10% in patients with hepatocellular carcinoma undergoing thermal ablation. Secondary objectives are to analyze the correlation between ablation margins and local recurrence and to assess efficacy.Materials and MethodsThis study is a prospective, multicenter, non-experimental, non-comparative, open-label study. Patients > 18 years with Barcelona Clinic Liver Cancer stage 0/A hepatocellular carcinoma (or B with a maximum of two lesions < 5 cm each) are eligible. Patients will undergo dual-phase contrast-enhanced computed tomography directly before and after ablation. Ablation margins will be quantitatively assessed using co-registration software, blinding assessors (i.e. two experienced radiologists) for outcome. Presence and location of recurrence are evaluated independently on follow-up scans by two other experienced radiologists, blinded for the quantitative margin analysis. A sample size of 189 tumors (~ 145 patients) is required to show with 80% power that the risk of local recurrence is confidently below 10%. A two-sided binomial z-test will be used to test the null hypothesis that the local recurrence rate is ≥ 10% for patients with a minimal ablation margin ≥ 2 mm. Logistic regression will be used to find the relationship between minimal ablation margins and local recurrence. Kaplan–Meier estimates are used to assess local and overall recurrence, disease-free and overall survival.DiscussionIt is expected that this study will result in a clear understanding of the correlation between ablation margins and local recurrence. Using co-registration software in future patients undergoing ablation for hepatocellular carcinoma may improve intraprocedural evaluation of technical success.Trial registration The Netherlands Trial Register (NL9713), https://www.trialregister.nl/trial/9713.

THE EFFECT OF GLYCERINE GEL AND MYLAR STRIP ON THE MARGINAL ADAPTATION OF COMPOSITE - LUTED INLAYS: AN IN VITRO RESEARCH

Background: Composite – luted ceramic inlays were one of the top choices for restorations of anterior and posterior teeth because of high aesthetic, good marginal adaptation and controllable anatomy and lateral contact. If the luting composite was exposed to air condition during polymerization, the presence of oxygen would interfere with polymerization of the adhesive surface layer, adversely affecting the prognosis of restorations. Therefore, it is very essential to evaluate different margin - treating techniques to prevent the formation of an oxygen - inhibited layer during the polymerization of composite resin materials. Objectives: The aim of this study was to examine the effectiveness of glycerine and Mylar strip on the marginal adaptation of composite - luted inlays. Methods: Thirty class II cavities were prepared on extracted human permanent premolars, randomly divided into three groups: group 1: e.max Press indirect inlays luted by Variolink II were polymerized in air; group 2: inlays were polymerized after applying glycerine on the restoration margins; group 3: inlays were covered by Mylar strip before light polymerization. To remove the oxygen - inhibited layer, the inlays were brushed with acetone. The clinical evaluation and computerized quantitative marginal analysis under digital microscope were carried out before and after applying acetone. Results: Statistical analysis revealed significant difference between the polymerization with and without the use of glycerine gel, specifically, the inlay margins of group 2 showed better marginal adaptation than group 1 did (p &lt; 0.001). Meanwhile, there was no statistical difference between group 2 and 3 in marginal quality of restorations. Conclusions: Oxygen-initated inhibition during polymerization can be prevented by the application of glycerine gel and Mylar strip to the surface of composite resin materials Key words: IPS e.max Press inlay, class II restoration, marginal adaptation, glycerine gel, Mylar strip.

Improving GPR Imaging of the Buried Water Utility Infrastructure by Integrating the Multidimensional Nonlinear Data Decomposition Technique into the Edge Detection

Although ground-penetrating radar (GPR) is effective to detect shallow-buried objects, it still needs more effort for the application to investigate a buried water utility infrastructure. Edge detection is a well-known image processing technique that may improve the resolution of GPR images. In this study, we briefly review the theory of edge detection and discuss several popular edge detectors as examples, and then apply an enhanced edge detecting method to GPR data processing. This method integrates the multidimensional ensemble empirical mode decomposition (MDEEMD) algorithm into standard edge detecting filters. MDEEMD is implemented mainly for data reconstruction to increase the signal-to-noise ratio before edge detecting. A quantitative marginal spectrum analysis is employed to support the data reconstruction and facilitate the final data interpretation. The results of the numerical model study followed by a field example suggest that the MDEEMD edge detector is a competent method for processing and interpreting GPR data of a buried hot spring well, which cannot be efficiently handled by conventional techniques. Moreover, the proposed method should be readily considered a vital tool for processing other kinds of buried water utility infrastructures.

Rapid high-intensity light-curing of bulk-fill composites: A quantitative analysis of marginal integrity

ObjectivesTo investigate the effect of rapid high-intensity light-curing on the marginal integrity of four bulk-fill composites, including two materials specifically designed for high-intensity curing. MethodsClass V cavities were prepared on buccal surfaces of intact human molars with simulated pulpal pressure, filled in a single increment and light-cured using a conventional (10 s @ 1,340 mW/cm2) or high-intensity (3 s @ 3,440 mW/cm2) protocol. The restorations were subjected to thermo-mechanical loading (TML) comprising 1,200,000 mechanical loading cycles and 3,000 thermocycles. Quantitative margin analysis was performed before and after TML using a scanning electron microscope, and the marginal integrity was expressed as percentage of continuous margin (PCM). ResultsAll PCM values measured before TML were statistically similar regardless of the material and curing protocol (p>0.05). A statistically significant effect of the curing protocol (p = 0.021) was identified only after TML for one material. PCM was significantly diminished by TML (p<0.001) for most combinations of material and curing protocol. The PCM values of the sculptable composites after TML were statistically similar regardless of the curing protocol (p>0.05). Compared to these values, significantly lower PCM after TML was identified for the flowable composites cured with the high-intensity protocol (p = 0.001–0.045). ConclusionIn most cases, high-intensity and conventional curing generally led to similar marginal integrity. Although all of the investigated composites initially performed similarly well, the flowable composites light-cured using the high-intensity protocol showed a significantly inferior marginal integrity compared to the sculptable composites after loading. Clinical significanceRapid high-intensity light-curing cannot be recommended for flowable bulk-fill composites since it may compromise the tooth-restoration interface.

International Consensus Contouring Recommendations for Stereotactic Body Radiotherapy of Non-Spine Bone Metastases

Despite the increasing use of stereotactic body radiotherapy (SBRT) for non-spine bone metastases (NSBM), there are no established guidelines for clinical target volume (CTV) delineation. The objective of this study was to provide recommendations on CTV delineation based on international expert consensus contours. Eleven cases were contoured by nine international radiation oncologists with demonstrated expertise in NSBM SBRT via publications and/or clinical experience. Cases included metastases in long bones (femur, humerus), pelvic bones (ilium, ischium, acetabulum, pubic symphysis) and thoracic bones (rib, sternum, scapula, clavicle). For each case the gross tumor volume (GTV) was provided on the simulation CT scans, which were accompanied by corresponding MR imaging. Experts then contoured the CTV and completed a clinical survey. Agreement between expert CTV contours was analyzed with simultaneous truth and performance level estimation (STAPLE) using the kappa coefficient and with the Dice similarity coefficient (DSC), and summarized to establish contouring recommendations. All CTV contours were completed for each of the eleven cases. Six experts used a single dose level, while 3 used a two-dose level (high dose and low dose) simultaneous integrated boost (SIB) technique. For the SIB cases, only the high dose CTV was used for contour analysis. There was substantial agreement between expert contours across cases with a mean and median kappa measure of 0.72 and 0.71 (range, 0.61-0.86), respectively. The mean and median DSC values were 0.77 and 0.79 (range, 0.67-0.87), respectively. Consensus CTV contouring recommendations consist of: 1) A ≤5mm intraosseous ± ≤5mm extraosseous margin beyond the GTV; 2) An extraosseous CTV margin should be strongly considered in cases of associated soft tissue disease and/or significant cortical bone disruption; 3) All CTVs should be manually modified to spare uninvolved joint spaces and organs-at-risk while respecting natural anatomical barriers (e.g. peritoneal cavity, pleura). Consensus CTV contouring recommendations for NSBM SBRT were established based on analysis of international expert consensus contours with a high level of agreement. Detailed quantitative margin analysis in three-dimensions is ongoing to define the optimal extent of CTV margins. Until prospective clinical data are available to inform patterns of failure, these recommendations may serve as guiding principles for treating physicians.

Margin Integrity of Bulk-Fill Composite Restorations in Primary Teeth.

This in vitro study examined the margin integrity of sculptable and flowable bulk-fill resin composites in Class II cavities of primary molars. Standardized Class II cavities were prepared in human primary molars and restored with the following resin composite materials after application of a universal adhesive: a sculptable bulk-fill composite (Tetric EvoCeram Bulk Fill (TEC) or Admira Fusion x-tra (AFX)), a flowable bulk-fill composite (Venus Bulk Fill (VBF) or SDR), or a conventional composite (Filtek Supreme XTE (FS)). The bulk-fill materials were applied in 4 mm layers, while the conventional composite was applied in either 2 mm (FS2, positive control) or 4 mm layers (FS4, negative control). The specimens were exposed to thermo-mechanical loading (TML) in a computer-controlled masticator. A quantitative margin analysis was performed both before and after TML using scanning electron microscopy, and the percentage of continuous margins (margin integrity) was statistically analyzed (α = 0.05). All composites showed a significant decline in margin integrity after TML. AFX exhibited the significantly highest margin integrity of all materials after TML (97.5 ± 2.3%), followed by FS2 (79.2 ± 10.8%), TEC (73.0 ± 9.1%), and FS4 (71.3 ± 14.6%). SDR (43.6 ± 22.3%) and VBF (25.0 ± 8.5%) revealed the lowest margin integrity. In conclusion, the tested sculptable bulk-fill materials show similar or better margin integrity in primary molars than the conventional resin composite placed in 2 mm increments.

Self-limiting caries excavation with a polymer bur: Adhesive bonding to residual dentin

ObjectivesThe aim of this study was to evaluate the bonding of an universal adhesive to residual affected dentin after polymer bur excavation of natural caries lesions in human teeth. Materials and methodsCaries excavation with a polymer bur and with a carbide bur were compared. A microtensile bond strength (μ-TBS) test was performed in a split-tooth design (n = 20/group). A universal adhesive (Scotchbond Universal, 3M-Deutschland, Neuss/Germany) was applied in either self-etch (SE) or total-etch (TE) mode. Qualitative and quantitative margin analysis was assessed before/after fatigue simulation (n = 8/group). Micro-CT examination was performed before/after polymerization of class-II restorations (Tetric EvoCeram BulkFill, Ivoclar-Vivadent, Schaan/Liechtenstein) (n = 6/group). Volumetric shrinkage and shrinkage vectors were calculated. The internal interface was analyzed under scanning electron microscopy after cutting the teeth. ResultsThe μ-TBS test revealed no significant difference between excavation methods. Mean tensile strengths (MPa) were: polymer-bur/SE = 16.0, polymer-bur/TE = 16.7, carbide-bur/SE = 15.5, carbide-bur/TE = 20.3, dentin/SE = 13.9, dentin/TE = 24.1. Margin analysis rated all groups >99% of perfect margin in dentin and enamel, no influence of excavation methods was found. Micro-CT examination revealed no difference between groups concerning volumetric shrinkage (1.9–2.5%). The shrinkage direction was towards the bonded area. Polymer bur excavation resulted in an irregular surface and thicker smear layer than with carbide bur. ConclusionCaries excavation with a polymer bur does not negatively affect bonding performance to residual affected dentin. Etching with phosphoric acid can further strengthen the interface.

Effect of Different Light Curing Intensities on Cavity Wall Adaptation of Nanofilled Resin Composite Using Transtooth Curing Technique: An In-vitro Study

Aim: to evaluate the cavity wall adaptation of nanofilled resin composite cured with different LED light intensities and with different thickness of buccal wall after thermocycling using environmental scanning electron microscope.Materials and methods: the materials used for this study was nanofilled resin composite material (Filtex Z350XT, 3M, ESPE) shade A3with its corresponding bonding system (single bond universal, 3M, ESPE). A total of 10 sound extracted human maxillary premolar teeth were used in this study. The teeth were divided into 2 main groups of 5 teeth each according to curing light intensities; either standard LED curing mode (800 mW/cm2) for 30 sec or high intensity LED curing mode (1400 mW/cm2) for 10 sec. In each tooth, 2 cavity preparations were performed; moderate cavity preparation width (1/3 intercuspal distance) in the mesial aspect of each tooth and wide cavity preparation (1/2 intercuspal distance) in the distal aspect. All specimens were light cured using transtooth curing technique from the buccal and lingual surfaces. All specimens were subjected to thermocycling protocol. All specimens were subjected to the quantitative margin analysis, examined using environmental scanning electron microscope (ESEM). Two ways analysis of variance (ANOVA) test was used to study the interaction of both variables. The significance level was set at p < 0.05. Results: Two ways ANOVA test revealed that the interaction of both variables was statistically significant (p=0.00). Comparing both intensities, a higher mean value was recorded in high intensity (6.57±1.29), with a significant difference (p=0.00). Comparing 1/2ICD and 1/3ICD, a higher mean value was recorded in 1/3ICD (6.52±2.19), with a significant difference (p=0.00). Conclusions: The wall thickness greatly affects the cavity wall adaptation in transtooth curing technique.Applying High intensity irradiation technique compromise margin quality and marginal seal of resin composite restoration.

Is Optical Coherence Tomography a Potential Tool to Evaluate Marginal Adaptation of Class III/IV Composite Restorations In Vivo?

Margin analysis of Class III and IV composite restorations in vitro and in vivo occurred by scanning electron microscopy (SEM) and optical coherence tomography (OCT). The results were compared and related to clinical evaluation. Eight Class III composite restorations were imaged in vitro using OCT and SEM. The margins were analyzed quantitatively. OCT signals were verified by assignment to the criteria perfect margin, gap, and positive/negative ledge. In vivo quantitative margin analysis of Class III/IV composite restorations made of the micro-hybrid composite Venus combined with the self-etch adhesive iBond Gluma inside (1-SE) or etch-and-rinse adhesive Gluma Comfort Bond (2-ER) (all Heraeus Kulzer) was carried out using OCT and SEM after 90 months of clinical function. The results were compared with clinical evaluation (US Public Health Service criteria; marginal integrity, marginal discoloration). In vitro, the correlation between OCT and SEM was high for all four margin criteria (Kendall tau b [τb] correlation: 0.64-0.92, pi≤0.026), with no significant differences between OCT and SEM (pi≥0.63). In vivo, a moderate correlation was observed (τb: 0.38-0.45, pi<0.016). Clinically, the cumulative failure rate in the criterion marginal integrity was higher for the 1-SE group (baseline 90 M, p=0.011). Similarly, OCT and SEM detected higher percentages of the criterion gap in the 1-SE group (p: 0.027/0.002), in contrast to perfect margin. Both, gap and perfect margin ranged widely between 0.0% and 88.7% (OCT) and between 0.0% and 89.0% (SEM). Despite the positive selection bias after 90 months with only a few patients left, quantitative margin analysis allows for differentiation between the two adhesives at this specific date. OCT in particular offers the possibility to evaluate marginal integrity directly in vivo.

Secondary caries formation with a two-species biofilm artificial mouth

ObjectivesThe present study aimed to establish Lactobacillus casei in a completely automated Streptococcus mutans-based artificial mouth model and to investigate secondary caries inhibiting properties of glass ionomer cements / resin composite groups in vitro. MethodsSixty extracted, caries-free human third molars were used for preparation of standardized class-V-cavities. Specimens were restored with a resin-modified (Photac Fil; PF) as well as a conventional glass ionomer cement (Ketac Molar; KM) and one resin composite bonded with and without conduction of etch-and-rinse technique (Prime&Bond NT, Ceram X mono; C+ERT, C). Following an incubation in distilled water for 28d at 37°C, specimens were exposed to 10,000 thermocycles (+5 °C/+55°C). A completely automated S. mutans-based (DSM No.: 20523) artificial mouth model was extended by establishment of L. casei (DSM No.: 20021). During microbiological loading, demineralization (4h/d) was caused by acid production resulting from bacterial glycolysis and artificial saliva was used for remineralization (20h/d). For quantitative margin analysis under am SEM, epoxy replicas were produced from impressions taken after thermocycling and after microbiological loading. Specimens were cut in half perpendicularly to restoration surfaces and demineralization depths at restoration margins and in 500μm distance from margins were evaluated by means of a fluorescence microscope (FITC filter). ResultsAfter microbiological loading, overall demineralization depths in enamel at restoration margin (EM) and in 500μm distance (ED) as well as in cementum/dentin at restoration margin (DM) and in 500μm distance (DD) were measured as follows (μm±SD): PF: EM 42±15, ED 60±17, DM 83±18; DD 127±16; KM: EM 46±22, ED 62±17, DM 104±21, DD 143±28; C+ERT: EM 67±19, ED 61±17, DM 165±31, DD 176±35; C: EM 65±23, ED 64±17, DM 161±27, DD 166±33. For the glass ionomer cements, the overall demineralization depths at restoration margins were significantly lower than in 500μm distance from margins (T-test, p<0.05). Especially at restoration margins in cementum/dentin, the resin composite groups showed significantly larger overall demineralizations than the glass ionomer cements (ANOVA, mod. LSD, p<0.05). Decreases of marginal quality were detected in all groups after microbiological loading (Friedman-test, p<0.05). SignificanceThe refined experimental setup was suitable for production of artificial secondary caries-like lesions. Glass ionomer cements as fluoride-releasing materials may show an inhibition of secondary caries formation to a certain extent.

Marginal quality and wear of extended posterior resin composite restorations: Eight-year results in vivo

AimTo evaluate wear and marginal quality of resin composite restorations over eight years of clinical service in vivo. Methods30 patients received 68 resin composite restorations (36 Grandio, 32 Tetric Ceram) in the course of a prospective clinical trial. 3-D evaluation of 36 selected teeth involving 144 epoxy replicas was carried out using a special 3-D scanning device with an accuracy of U1=2.5+L/350μm; U3=3+L/300μm. In vivo replicas were sputter-coated with gold and examined under a SEM at 200× magnification. Marginal integrity between resin composite and enamel was expressed as a percentage of the entire judgeable margin length. ResultsDuring the clinical 8-year observation period, wear significantly increased in the restored areas as well as in OCAs. RBCs under investigation showed no significant differences regarding wear (p>0.05). Localization of the restorations (premolar vs. molar or upper vs. lower) did not show a significant influence on wear rates (p>0.05). Clinically, by SEM, and by 3-D scanning distinct changes of worn contours on enamel and RBC were visible. Quantitative margin analysis revealed a change of perfect margins (58% at baseline vs. 14% at 8 years), positive step formations (15% at baseline vs. 10% at 8 years), and negative step formations (20% at baseline vs. 71% at 8 years) over time (p<0.001). Regarding the portion of gap-free margins (baseline vs. 2 years) and total margin length (baseline to 8 years), Grandio showed lower values (Mann-Whitney U-test; p<0.05). The portion of negative step formations was lower for Tetric Ceram at baseline (Mann-Whitney-U test; p<0.05). ConclusionsAfter eight years of clinical service, neither wear nor marginal quality was a critical factor for estimation and survival of extended posterior resin composite restorations.

Bulk filling of Class II cavities with a dual-cure composite: Effect of curing mode and enamel etching on marginal adaptation.

Objectives: This study attempted to find a simple adhesive restorative technique for class I and II cavities on posterior teeth. Study Design: The tested materials were a self-etching adhesive (Parabond, Coltène/Whaledent) and a dual-cure composite (Paracore, Coltène/Whaledent) used in bulk to restore the cavities. Class II MO cavities were performed and assigned to 4 groups depending on the orthophosphoric acid (H3PO4) conditioning of enamel and polymerization method used (chemical or dual). Specimens were subjected to quantitative marginal analysis before and after thermo-mechanical loading. Results: Higher percentages of marginal adaptation at the total margin length, both before and after thermo-mechanical loading, were found in groups in which enamel was etched with phosphoric acid, without significant differences between the chemically and dual-cured modes. The restorations performance was similar on enamel and dentin, obtaining low results of adaptation on occlusal enamel in the groups without enamel etching, the lowest scores were on cervical dentin in the group with no ortophosphoric acid and self-cured. Conclusions: A dual-cure composite applied in bulk on acid etched enamel obtained acceptable marginal adaptation results, and may be an alternative technique for the restoration of class II cavities. Key words:Dual-cure composite, bulk technique, class II restoration, selective enamel etching, marginal adaptation.

Age and growth of two newly established invasive populations of Tilapiamariae in northern Australia

Sagittal otoliths were used to age the samples of Tilapia mariae collected from a coastal river and an impoundment. Validation of sagittae checks was achieved using both quantitative marginal increment analysis and by tetracycline marking of the otoliths of fish kept in tanks and in a farm dam. The annulus pattern on the otoliths was generally clear and their formation appeared to be temperature related and largely completed in the Austral spring around September and October. Male T. mariae grow faster and larger than females and the maximum ages of fish from the coastal river and impoundment was 9+ and 4+ years, respectively. Past fish surveys and the absence of older age classes in the impoundment population would suggest that this population was only very recently established.

Effect of Polishing Direction on the Marginal Adaptation of Composite Resin Restorations

Polishing composite resin restorations may lead to marginal defects and gap formation. To assess the effect of polishing direction on the marginal adaptation of composite resin restorations using two composite resins and two polishing systems. Forty extracted human molars were sectioned along their mesio-distal axis. Buccal and lingual enamel was flattened and a triangular preparation, 0.87-mm deep and 3-mm wide, representing two 60° bevels, was performed. Specimens were randomly assigned to eight groups (N = 20) and restored with two composite resins: a nanofilled (Filtek Supreme Ultra, 3M ESPE, St. Paul, MN, USA) or a microhybrid (Point 4, Kerr, Orange, CA, USA) and finished with two polishing techniques: polishing discs (Sof-Lex XT, 3M ESPE) or rubber polishers (HiLuster Plus, Kerr, Bioggio, Switzerland). On each specimen, both margins were polished with the same technique, one margin from composite resin to tooth and the other from tooth to composite resin. Replicas were made for field emission scanning electron microscope observation (200×) and quantitative margin analysis was performed based on four criteria. Data were analyzed with a paired-sample t-test, a two-sample t-test, and one-way analysis of variance or their nonparametric analog. Significant differences were found in most groups between polishing directions with better marginal adaptation from composite resin to tooth than from tooth to composite resin. Differences between composite resins and polishing techniques seemed to be dependent on certain combinations of composite resin, polishing technique, and polishing direction. Polishing from composite resin to tooth leads to better marginal adaptation than polishing from tooth to composite resin. The results obtained from this in vitro study suggest that polishing direction influences the marginal adaptation of composite resins and that polishing from composite resin to tooth structure should be clinically performed whenever possible on accessible margins to preserve marginal integrity and esthetics.

Self-etching aspects of a three-step etch-and-rinse adhesive

The purpose of this study is to assess the marginal adaptation of cavities restored with a three-step etch-and-rinse adhesive, OptiBond FL (OFL) under different application protocols. Twenty-four class V cavities were prepared with half of the margins located in enamel and half in dentin. Cavities were restored with OFL and a microhybrid resin composite (Clearfil AP-X). Three groups (n = 8) that differed in the etching technique were tested with thermomechanical loading, and specimens were subjected to quantitative marginal analysis before and after loading. Micromorphology of etching patters on enamel and dentin were observed with SEM. Data was evaluated with Kruskal-Wallis and Bonferroni post hoc test. Significantly lower percent CM (46.9 ± 19.5) were found after loading on enamel in group 3 compared to group 1 (96.5 ± 5.1) and group 2 (93.1 ± 8.1). However, no significant differences (p = 0.30) were observed on dentin margins. Etching enamel with phosphoric acid but avoiding etching dentin before the application of OFL, optimal marginal adaptation could be obtained, evidencing a self-etching primer effect. A reliable adhesive interface was attained with the application of the three-step etch-and-rinse OFL adhesive with a selective enamel etching, representing an advantage on restoring deep cavities.

The competition between enamel and dentin adhesion within a cavity: An in vitro evaluation of class V restorations

To gain more insight into the consequences of curing contraction within the tooth cavity, we assessed the margin behavior of 12 contemporary restorative systems in class V restorations with margins located on enamel and dentin after mechanical loading and water storage. Mixed class V cavities were prepared on extracted human molars and restored using five etch and rinse and seven self-etch adhesive systems with their corresponding composites. Marginal adaptation was evaluated by using a computer-assisted quantitative marginal analysis in a scanning electron microscope (SEM) on epoxy replicas before, after thermal and mechanical stressing and after 1 year of water storage. The interactions of "testing conditions", "adhesive-composite combination" and "tooth substrate" with "marginal adaptation" were evaluated by two-way ANOVA. Fatigue, stress and storage conditions had significant effects on the marginal adaptation. Only two groups (Optibond FL and G Bond) presented equal percentages of marginal adaptation on enamel and dentin; in the other groups, the rate of degradation was product dependent. All materials tested showed a distinct behavior on enamel and dentin. In addition to mechanical resistance and long-term stability, differences within materials also exist in their ability to simultaneously bond to enamel and dentin.