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Brazilian Oral Research Mar 2019The aim of this study was to evaluate the degree of conversion (DC) and the thermal stability of bulk-fill and conventional composite resins. Eleven composite resin... (Comparative Study)
Comparative Study
The aim of this study was to evaluate the degree of conversion (DC) and the thermal stability of bulk-fill and conventional composite resins. Eleven composite resin samples were prepared to evaluate the DC, Vickers microhardness (VMH), mass and residue/particle loss, glass transition temperature (Tg), enthalpy, and linear coefficient of thermal expansion (CTE) using infrared spectroscopy (FTIR), microdurometer analyses, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dilatometry (DIL). The data were subjected to statistical analysis, with a significance level of 95%. DC and VMH were not influenced by the polymerized side of the sample, and statistical differences were recorded only among the materials. Decomposition temperature, melting, and mass and residue loss were dependent on the material and on the evaluation condition (polymerized and non-polymerized). Tg values were similar between the composites, without statistically significant difference, and CTE ranged from 10.5 to 37.1 (10-6/°C), with no statistical difference between the materials. There was a moderate negative correlation between CTE and the % of load particles, by weight. Most resins had a DC above that which is reported in the literature. TGA, Tg, and CTE analyses showed the thermal behavior of the evaluated composites, providing data for future research, assisting with the choice of material for direct or semidirect restorations, and helping choose the appropriate temperature for increasing the DC of such materials.
Topics: Composite Resins; Dental Materials; Hardness; Materials Testing; Spectrophotometry, Infrared; Surface Properties; Temperature
PubMed: 30892408
DOI: 10.1590/1807-3107bor-2019.vol33.0008 -
Dento Maxillo Facial Radiology Mar 2019To investigate the influence of high-density dental material on the automatic exposure compensation of digital radiographic imaging systems.
OBJECTIVES:
To investigate the influence of high-density dental material on the automatic exposure compensation of digital radiographic imaging systems.
METHODS:
Two radiographic phantoms were custom made to reproduce radiographic densities of the dental tissues: enamel, dentin and pulp chamber. The phantoms were X-rayed using the Digora Toto, Digora Optime and VistaScan systems for 0.063, 0.1 and 0.16 s. Radiographic acquisitions were repeated in the presence of a high-density material equivalent to a titanium implant, in the small and large sizes. Mean grey values of the dental tissue-equivalent regions were obtained with the Image J software, averaged and compared between the absence and presence of the high-density material using ANOVA for multiple comparisons and Tukey's test (α = 0.05).
RESULTS:
The presence of a high-density material significantly (p ≤ 0.05) decreased grey values of the dental tissue-equivalent images in the Digora Toto and VistaScan, regardless of the exposure time. For the Digora Optime, the high-density material decreased the pulp-equivalent grey values at all exposure times, the dentin-equivalent grey values significantly increased at exposure time of the 0.1 and 0.16 s, and the enamel-equivalent grey values significantly increased at the exposure time of 0.16 s (p ≤ 0.05). In general, the size of the high-density material did not affect the grey values significantly (p ≤ 0.05).
CONCLUSIONS:
In general, the presence of a high-density dental material in digital radiographic systems influences the AEC by adjusting dental tissue-equivalent grey values.
Topics: Dental Materials; Dental Pulp Cavity; Dentin; Pilot Projects; Radiography, Dental, Digital
PubMed: 30540916
DOI: 10.1259/dmfr.20180331 -
Journal of Oral Science Oct 2021To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in...
PURPOSE
To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in primary molars.
METHODS
Occluso-mesial cavities in second primary artificial molars were randomly restored using different materials (Filtek Z500 or Filtek Bulk Fill composites or high-viscosity glass ionomer cement Ketac Universal) and different matrix system (Tofflemire, AutoMatrix, matrix band with ring, contoured sectional matrix) (n = 12). Proximal contact tightness was measured using a custom-made device in an Instron 3345, and proximal surface morphology and marginal adaptation were scored after digital scanning. Two-way ANOVA, Tukey and Fischer's exact tests were performed (P < 0.05).
RESULTS
Proximal contact tightness values were significantly influenced by the restorative material (P < 0.05), the matrix system (P < 0.001), and their interaction (P < 0.01). Both resin composites showed statistically differences in proximal shape according to the matrix used to restore and exhibited overhanging margins. Ketac Universal restorations showed similar morphology and gaps on the margins regardless of the matrix system.
CONCLUSIONS
Overall, both composite restorations achieved tighter proximal contact than those restored with the high-viscosity glass ionomer cement. None of the matrix systems tested provided a convex seamless proximal morphology.
Topics: Dental Materials; Glass Ionomer Cements; Molar; Tooth, Deciduous; Viscosity
PubMed: 34511588
DOI: 10.2334/josnusd.21-0264 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Dec 2019Resin composite, which is commonly used as a dental filling material, has some problems, such as poor wear resistance, polymerization shrinkage, and poor dentin marginal... (Review)
Review
Resin composite, which is commonly used as a dental filling material, has some problems, such as poor wear resistance, polymerization shrinkage, and poor dentin marginal adaptability. Preheating of resin composite improves its pro-perties. This paper reviewed the effects of resin composite preheating on its monomer conversion, marginal microleakage, mechanical properties, and irritation on dental pulp.
Topics: Composite Resins; Dental Leakage; Dental Materials; Dental Restoration, Permanent; Materials Testing; Surface Properties
PubMed: 31875432
DOI: 10.7518/hxkq.2019.06.001 -
Dental Materials : Official Publication... Dec 2023To evaluate retrospectively the longevity of lithium disilicate ceramic (LidiSi) vs. laboratory-processed resin-based composite (RBC) inlay/onlay/overlay restorations...
OBJECTIVE
To evaluate retrospectively the longevity of lithium disilicate ceramic (LidiSi) vs. laboratory-processed resin-based composite (RBC) inlay/onlay/overlay restorations and risk factors associated with restoration deficiencies and failures.
METHODS
Patients (n = 91) receiving LidiSi (73.1%) and RBC (36.9%) inlays/onlays/overlays between 2007 and 2017 were selected. The restorations were evaluated using the modified U.S. Public Health Service criteria. The survival of the restorations was analyzed using the Kaplan-Meier method and log rank test. Factors affecting the occurrence of deficiencies were examined by logistic regression analysis. This was performed with the use of the Generalized Estimating Equation model including Repeated measurements (GEER), with the consideration that the same patient had several teeth in the sample. Risk estimation was conducted for each evaluated criterion (p < 0.05).
RESULTS
The survival of LidiSi and RBC restorations were 96.8% and 84.9%, respectively after a mean observation period of 7.8 ± 3.3 years. The annual failure rate was 0.2% for LidiSi and 1.0% for RBC. The probability of survival was above 98% for both restorations in the first 6 years, however, it dropped to 60% for RBC by the end of the 15th year. For both materials the reasons for failure included secondary caries, restoration fracture, and endodontic complication. In addition, LidiSi also failed due to tooth fracture, while RBC due to marginal gap formation and loss of retention. Among the evaluated risk factors, material of restoration (OR=6.8, CI:3.1-14.9), oral hygiene (OR=8.0, CI: 2.9-22.1], and bruxism (OR=1.9, CI: 1.1-3.3) showed a significant impact on the evaluated criteria.
SIGNIFICANCE
LidiSi and RBC restorations showed similarly excellent 6-year survival, however, in the long term significantly more failures should be expected for RBCs.
Topics: Humans; Retrospective Studies; Dental Restoration Failure; Dental Porcelain; Composite Resins; Dental Materials; Ceramics; Inlays
PubMed: 37821330
DOI: 10.1016/j.dental.2023.10.017 -
International Journal of Implant... Oct 2022Based on the excellent long-term data, dental implants made of titanium are considered the international implantological standard for replacing missing teeth. However,...
PURPOSE
Based on the excellent long-term data, dental implants made of titanium are considered the international implantological standard for replacing missing teeth. However, ceramic implants made of zirconia (ZrO) have experienced a renaissance in the last 15 years due to constant innovations in materials and products, with material properties and soft tissue- and osseointegration behavior comparable to those of titanium. However, one limitation concerning ceramic implants is the lack of reliable long-term data, especially in the case of two-piece implant systems. As there is an increasing demand for ceramic implants from practitioners and patients, the German Society for Implantology (DGI) has decided to develop a guideline on the use of dental ceramic implants at the highest available evidence level with the involvement of experts in this field.
METHODS
Statements and recommendations were prepared after conducting a systematic literature search and an independent assessment process involving the relevant clinical literature from 2008 to 2021. The adopted recommendations and statements are summarized in this guideline.
RESULTS AND CONCLUSIONS
It confirms the feasible use of one-piece zirconia implants as an addendum/alternative to titanium implants. No final conclusion regarding the application of two-piece ceramic implant systems could be drawn on the basis of the existing data, thus its use can only be recommended after the patient has been informed in detail about the lack of long-term clinical data.
Topics: Ceramics; Dental Implants; Dental Materials; Humans; Titanium; Zirconium
PubMed: 36190587
DOI: 10.1186/s40729-022-00445-z -
Beijing Da Xue Xue Bao. Yi Xue Ban =... Dec 2008The concept of computer-aided design/computer aided manufacturing (CAD/CAM) was first mentioned decades ago in the field of dentistry. The technology to make dental... (Review)
Review
The concept of computer-aided design/computer aided manufacturing (CAD/CAM) was first mentioned decades ago in the field of dentistry. The technology to make dental restorations has found wide application recently and developed rapidly in prosthodontics and oral implantology, for it could save patients' time and manpower, have precision on prostheses' edging, etc. Until now there are several commercial CAD/CAM systems on market. With the use of CAD/CAM technology in dentistry, it has broken the traditional pattern of making dentures manually. Meanwhile, it brings opportunity for material science. The machinable/milled materials in dentistry should have not only excellent biocompatibility, but also machining and physical properties. Both of them are important. Nowadays, a great number of blocks are made from feldspar ceramics, glass-ceramics, alumina oxide, zirconium oxide, titanium, composite materials, wax and so on. Lots of researchers have had their focus on metal-free materials, because it can make the restorations look more natural and not show the inside metal color. However, strength like feldspar ceramics has its own disadvantages. It has strict indications, otherwise the restoration may fail. The technique called In-Ceram has been used long time ago. It also has long clinical experience and excellent long-term prognosis. People have explored this technique in CAD/CAM restorations. Studies have manifested that it can be utilized this way. At first, alumina was milled with pores; then, glass was infiltrated to the milled material. After zirconia had its success used in orthopedics, it became more and more popular to investigate whether this stuff was suitable in dentistry or not. Luckily, it has been proved adaptable for making single crown in posterior area, fixed partial dentures, in particular, and milling it using CAM equipment, due to the partially sintered block's hardness like chalk. Several milled polymer materials are made for temporary crowns or bridges. In recent years, because of the phenomenon about microleakage of the direct filling composite resin intraoral, indirect filling method, inlay, by the adhesive agent has bonded the tooth tissue and the material to eliminate the microleakage. It is the chemical bonding. As a result of this, maybe composite material made inlay will be prospective. As the aging phenomenon of the polymers are inevitable, and the resin matrix are polymers, it is not suitable for cosmetic restorations. Metal materials for CAD/CAM have some commercial products. But few scholars do the studies about it. In this article you will find that many investigators abroad do the research about the commercial blocks on their physical and clinical study. On the other hand, domestic scholars pay attention to the basis of the material research. It provides the overview of the materials for CAD/CAM in dentistry.
Topics: Ceramics; Composite Resins; Computer-Aided Design; Dental Materials; Dental Prosthesis Design; Humans; Zirconium
PubMed: 19088843
DOI: No ID Found -
Polimery W Medycynie 2022Resin composites have various applications. At the same time, they have some drawbacks, such as polymerization shrinkage. Conventional composites are polymerized in 2-mm...
BACKGROUND
Resin composites have various applications. At the same time, they have some drawbacks, such as polymerization shrinkage. Conventional composites are polymerized in 2-mm thick layers. However, in posterior restoration, the 2-mm depth of cure is not satisfactory. To find a solution, resin composites have been vastly improved in terms of fillers, matrix and initiators.
OBJECTIVES
To evaluate polymerization properties and physical characteristics of fiber-reinforced composites and compare them with bulk-fill composites that are designed for large posterior restorations.
MATERIAL AND METHODS
Samples were prepared from each resin composite. The 3-point bending test was performed to evaluate the flexural strength of all composites. The depth of cure of the composite from 1 mm to 4 mm of depth was analyzed using Vickers hardness test (VHN). To analyze the degree of conversion, Fourier-transform infrared spectroscopy (FTIR) of the top and bottom surfaces of the samples with 4-mm thickness was calculated. The data were analyzed using one-way analysis of variance (ANOVA) test followed by post hoc test (95% confidence interval (95% CI)).
RESULTS
The Filtek showed the highest flexural strength followed by everX and X-tra fil. At 1-mm depth, X-tra fil had the highest and Gradia had the lowest microhardness. At the 4-mm depth, the microhardness trend was as follows: everX > Filtek > X-tra fil > Gradia > Beautifil. The everX composite had the lowest reduction of the degree of conversion at 4-mm thickness, which showed a significant difference in comparison with Filtek, Gradia and X-tra fil composites.
CONCLUSIONS
Based on the results of our study, it can be concluded that the fiber-reinforced composite everX showed more favorable results regarding polymerization properties, such as the degree of conversion and the depth of cure. However, the flexural strength results in Filtek were better than those in everX.
Topics: Composite Resins; Dental Materials; Hardness; Hardness Tests; Materials Testing; Polymerization; Spectroscopy, Fourier Transform Infrared; Surface Properties
PubMed: 35801996
DOI: 10.17219/pim/151857 -
Dental Materials : Official Publication... Aug 2023This prospective practice-based trial assessed the longevity of composite restorations made with an adhesive containing an antibacterial monomer compared to a... (Clinical Trial)
Clinical Trial
OBJECTIVES
This prospective practice-based trial assessed the longevity of composite restorations made with an adhesive containing an antibacterial monomer compared to a conventional adhesive.
METHODS
9 general practices in the Netherlands were provided with two composite resin adhesives, each for a period of 9 months. Adhesive P contained the quaternary ammonium salt MDPB, and Adhesive S was a control. Patient's age and caries risk, as well as tooth type/number, reason for restoration placement, used restorative material and adhesive, and restored surfaces were recorded. All interventions carried out on these teeth in the 6 years after restoration were extracted from the electronic patient records, along with their date, type, reason, and surfaces. Two dependent variables were defined: general failure, and failure due to secondary caries. All data handling and multiple Cox regression analysis were carried out in R 4.0.5.
RESULTS
11 dentists from 7 practices made 10,151 restorations over a period of two years in 5102 patients. 4591 restorations were made with adhesive P, whereas 5560 were made with adhesive S. The observation period was up to 6.29 years, median observation time was 3.74 years. Cox regression showed no significant difference between the two adhesive materials when corrected for age, tooth type and caries risk, for general failure nor failure due to caries.
SIGNIFICANCE
No difference in restoration survival could be shown between composite restorations made using an adhesive containing MDPB and control. Restorations made with the adhesive containing MDPB also did not fail more or less frequently due to secondary caries. This trial is registered on clinicaltrials.gov with identifier NCT05118100.
Topics: Humans; Composite Resins; Dental Caries; Dental Cements; Dental Materials; Dental Restoration Failure; Dental Restoration, Permanent; Prospective Studies
PubMed: 37394389
DOI: 10.1016/j.dental.2023.06.011 -
Clinical Oral Investigations Mar 2021Sufficient depth of cure allows bulk-fill composites to be placed with a 4-mm thickness. This study investigated bulk versus incremental application methods by...
OBJECTIVES
Sufficient depth of cure allows bulk-fill composites to be placed with a 4-mm thickness. This study investigated bulk versus incremental application methods by visualizing shrinkage vectors in flowable bulk-fill and conventional composites.
MATERIALS AND METHODS
Cylindrical cavities (diameter = 6 mm, depth = 4 mm) were prepared in 24 teeth and then etched and bonded with OptiBond FL (Kerr, Italy). The composites were mixed with 2 wt% radiolucent glass beads. In one group, smart dentin replacement (SDR, Dentsply) was applied in bulk "SDR-bulk" (n = 8). In two groups, SDR and Tetric EvoFlow (Ivoclar Vivadent) were applied in two 2-mm-thick increments: "SDR-incremental" and "EvoFlow-incremental." Each material application was scanned with a micro-CT before and after light-curing (40 s, 1100 mW/cm), and the shrinkage vectors were computed via image segmentation. Thereafter, linear polymerization shrinkage, shrinkage stress and gelation time were measured (n = 10).
RESULTS
The greatest shrinkage vectors were found in "SDR-bulk" and "SDR-increment2," and the smallest were found in "SDR-increment1-covered" and "EvoFlow-increment1-covered." Shrinkage away from and toward the cavity floor was greatest in "SDR-bulk" and "EvoFlow-increment2," respectively. The mean values of the shrinkage vectors were significantly different between groups (one-way ANOVA, Tamhane's T2 test, p < 0.05). The linear polymerization shrinkage and shrinkage stress were greatest in Tetric EvoFlow, and the gelation time was greatest in "SDR-bulk."
CONCLUSIONS
The bulk application method had greater values of shrinkage vectors and a higher debonding tendency at the cavity floor.
CLINICAL RELEVANCE
Incremental application remains the gold standard of composite insertion.
Topics: Composite Resins; Dental Caries; Dental Materials; Humans; Italy; Materials Testing; Polymerization; X-Ray Microtomography
PubMed: 32653992
DOI: 10.1007/s00784-020-03412-3