Cause Of Restoration Failure Research Articles

Synthesis and challenges of fluorinated divinyl urethane monomers as a strategy for masking hydrolytic sensitive methacrylate groups in resin composites

ObjectiveThe biodegradation of methacrylate (MA)-based dental restoratives has been suggested to contribute to a loss of adhesion and subsequent detachment, or secondary caries, both major causes of restoration failure. Previous studies have demonstrated that intermolecular interactions between resin monomers may affect the hydrolytic-susceptibility of composites. Altering the intermolecular interactions by shielding or masking the hydrolytically-susceptible ester groups found in MA monomers could be an effective strategy to mitigate the biodegradation of resin composites. The objective of this work was to assess whether shielding/masking MAs using fluorinated groups could improve the biostability of experimental composites. MethodsEight fluorinated monomers (FM) were synthesized, characterized (1H NMR), and formulated into experimental resin composites (FC, 65 wt%, microfill). FCs were assessed for interactions with water (water contact angle, water sorption, gel fraction), mechanical properties (both compressive and flexural strength and modulus), cytocompatibility, resistance to biodegradation using simulated human salivary esterase (SHSE) and compared to a control composite (CC) without FM. ResultsIntegration of FMs was found to generally decrease both the physical and mechanical properties under all incubation conditions when compared to the CC. Additionally, all FCs had a negative influence on composite biodegradation following immersion in SHSE when compared to the CC. SignificanceShielding/masking MA-esters inherently inserts molecular spaces between the polymer chains within the resin network, and shielding is likely not possible while also maintaining the necessary cohesive forces that regulate the physical and mechanical properties of resin composites. Novel dental resin development should seek to remove/replace vulnerable ester-containing MAs rather that adopting a shielding/masking approach.

Effect of etching time duration on the push out strength of self adhesive cement to root dentin

Introduction: Post debonding is one of the most important causes of restoration failure in endodontically treated teeth restored with fiber-post. The weakest connection in post-cement-dentin complex is cement-dentin bonding surface. In this study we evaluated the effect of etching with phosphoric-acid and its duration on push-out strength of self-adhesive resin cement to dentin. Materials and Method: Root canal therapy was done for fifty intact one-canal premolars then the crown was cut from CEJ. Fiber-post space was prepared in the root canal by FGM special drill. The teeth were randomly divided into five groups of ten teeth. Group without any intervention was considered as control-1 and the other groups were prepared for etching. Three groups were etched with 37%phosphoric-acid for 15seconds, 60seconds and 90seconds. In the last group, after preparation, etching protocol wasn't performed which was considered as control-2. In all samples, White post fiber-ost(FGM) size2 was cemented with self-adhesive cement TheraCem (Bisco) and divided into two 4mm pieces and then mounted in acryl. Push-out test was performed by Instron machine for each sample and the shear bond strength was obtained in MPa.

In vitro attrition wear resistance of four types of paste-like bulk-fill composite resins

BackgroundRecently, the application of bulk-fill composite resins has increased significantly. Attrition wear and the consequently increased surface roughness of composite resins are among the causes of restoration failure in the posterior teeth. This study aimed to compare the attrition wear and surface roughness of four types of bulk-fill composite resins compared to a conventional composite resin.MethodsEverX-Posterior, X-tra fil, SonicFill 2, and Filtek Bulk-Fill composites (bulk-fill) and Z250 composite (conventional resin composite) were evaluated. Thirty cylindrical specimens (n = 6) were weighed and monitored for 24 h until their weight was stabilized. The primary surface roughness of the specimens was measured by a profilometer. The specimens were then subjected to attrition wear in a chewing simulator. Next, the specimens were weighed, and the surface roughness was measured again. Data were analyzed by one-way ANOVA and Tukey’s post-hoc test at P < 0.05 significance level.ResultsAccording to one-way ANOVA, the difference in weight loss was significant among the groups (P = 0.004) but the difference in surface roughness of the groups was not significant after the attrition wear (P > 0.05). Tukey’s post-hoc test showed that the weight loss of bulk-fill composites was not significantly different from that of Z250 conventional composite after the attrition wear (P > 0.05).ConclusionWithin the limitations of this study, it appears that the tested bulk-fill composite resins are comparable to the conventional composite regarding their attrition wear, increased surface roughness, and weight loss.

Microleakage Evaluation in Class V Cavities Restored with Five Different Resin Composites: In vitro Dye Leakage Study.

PurposeRestorative materials and techniques have improved the clinical success of a variety of restorative procedures. Despite these new improvements, microleakage remains one of the leading causes of restoration failure and may lead to postoperative sensitivity, enamel microcracks, marginal staining, discoloration, recurrent caries, and deformation of teeth. This study evaluated microleakages of five recent resin composites in class V cavities.Materials and MethodsStandardized class V cavities were prepared on the labial surfaces of one hundred extracted intact and noncarious human permanent premolar teeth. The cavities were divided into five groups (n=20) according to the resin composite material. Groups: A1, A2, A3, A4 and A5 were restored with Omnichroma, Spectrum, Mosaic, Tetric N-Ceram and Harmonize, respectively. The teeth were stained with methylene blue and then sectioned, and the extent of dye penetration was examined under a stereomicroscope and scanning electron microscope (SEM) to evaluate microleakage. One-way ANOVA test was used to statistically analyze the data. Statistical Package for Social Sciences Computer Software (SPSS) version 15.0 was used.ResultsDye penetration was observed at the tooth-restoration interface in all the studied samples, with varying degrees of penetration. At the cervical margins of the cavities, no statistically significant difference in the microleakage scores was observed (P=0.16). At the cavity floor, no statistically significant difference in microleakage scores was observed (P=0.74). Omnichroma resin composite had the highest microleakage results.ConclusionNanohybrid resin composites showed less microleakage than other resin composites. Among all the groups, Omnichroma showed the highest microleakage at the cavity floor and at the cervical areas.Clinical SignificanceIn light of our findings, nanohybrid resin composites appear to be capable of reducing microleakage, and the results reported herein must be verified by additional clinical trials.

Adhesive systems modified with antimicrobial agents: a literature review

Secondary caries is the primary cause of restoration failure. Thus, the development of adhesives with antimicrobial action is an advantageous option for their inhibition. However, this effect must be proven, as well as that the additional benefit does not interfere with material mechanical properties or biocompatibility. We analyzed adhesives with antimicrobial action by microbiological tests, bond strength, degree of conversion, and cytotoxicity. We analyzed 32 studies with commercially available antimicrobial adhesives (Clearfil™ SE Protect Bond/ MDPB, Gluma 2Bond/ glutaraldehyde, Peak Universal Bond/chlorhexidine), and experimental materials or commercial adhesives modified with antimicrobial agents, including materials with quaternary ammonium methacrylate (QAM) [dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM)], nanoparticles [silver (NAg), titanium dioxide (TiO2), zinc oxide (ZnO)], silver or zinc doped bioactive active glass (BAG), titanium, copper iodide, and compounds such as triclosan, quercetin, grape seed extract, among others. The use of antimicrobial agents is a favorable perspective for the functionalization of adhesive systems to inhibit secondary caries. However, more clinical studies need to prove the efficacy of these materials.

Clinical Performance of Direct Posterior Composite Restorations with and without Short Glass-fiber-reinforced Composite in Endodontically Treated Teeth: 3-year Results.

To evaluate the clinical performance of direct posterior composite restorations with and without short glass-fiber (SGF) reinforced composite in endodontically treated teeth. Twenty-four patients (mean age 32.5 years) were included in the study and two molars of each patient received endodontic treatment. After endodontic treatment, one tooth was restored with G-aenial Bond/fiber-reinforced composite (everX Posterior GC) using a microhybrid composite (G-aenial Posterior), and the other tooth was restored with G-aenial Bond/microhybrid composite (G-aenial Posterior). The modified USPHS criteria were used to evaluate the restorations at baseline, 1-, 2-, and 3-year follow-ups. The success rate of the everX Posterior and G-aenial Posterior restorations after 3 years was 78.3% and 91.3%, respectively. Five everX Posterior restorations and two G-aenial Posterior restorations failed. Based on the criteria used in this study, no significant differences between the two restorations were found at any evaluation time. All restorations showed acceptable clinical performance regarding all evaluation criteria, apart from the failed restorations. The main cause of restoration failure was restoration fracture. The failure rate of everX Posterior restorations was higher than G-aenial Posterior restorations.

Marginal Leakage of Class V Composite Resin Restorations

Introduction: Marginal leakage is one of the significant causes of restoration failure. This in-vitro study was conducted to compare cone beam computed tomography (CBCT) and dye-penetration methods for determining marginal leakage at gingival surface of class V resin composite restorations. Materials and Methods: Class V cavities were prepared on the buccal surfaces of nineteen caries-free extracted human molar teeth. Cavities were conditioned and filled. The teeth were immersed in a 50% w/w aqueous silver nitrate solution for 24 h and were taken out and rinsed with distilled water. Then, they were put into a developing solution. Whole specimens were first viewed with CBCT and were then sectioned and evaluated by stereomicroscope. Results: Measurement of agreement between CBCT and stereomicroscope revealed that 15 (78.9%) teeth had score 0, 1 (5.3%) tooth had score 1, and 1 (5.3%) tooth had score 2 in both techniques. Measurement of agreement between CBCT and stereomicroscope techniques, in the detection of marginal leakage, was 89.5% (Kappa coefficient = 0.627, P = 0.00). The Wilcoxon paired rank test revealed no significant difference between the results of CBCT and stereomicroscope in measuring the leakage at gingival margin (P = 0.157). Conclusion: Considering the limitations of the study, there was no significant difference between the results of CBCT and stereomicroscope in measuring the leakage at gingival margin of class V composite restorations. CBCT can be used noninvasively to detect the marginal leakage of gingival wall of class V composite restorations using aqueous silver nitrate solution as a tracer.

Review of microleakage evaluation tools

The advancement of restorative materials and techniques continues to enhance the clinical success of numerous restorative procedures. Despite these new innovations, microleakage persists as one of the main causes of restoration failure. Microleakage tests provide useful information on the performance of restorative materials, and different techniques for assessing microleakage have been developed and used. These tests include the use of dyes, radioactive isotopes, air pressure, bacteria, neutron activation analysis, and artificial caries. However, little has been done to determine the cause, mechanism, and nature of microleakage. Therefore, this review outlines and discusses the currently available microleakage assessment tools.

Effect of addition of chitosan on water sorption, solubility and microhardness of glass ionomer cement

Background A glass ionomer cement (GIC) restorative materials is commonly used in dentistry for permanent cementation of indirect restorations, liner, base or as atraumatic restorative treatment for the restoration of primary teeth, especially in developing countries. Water sorption and solubility of dental cement could be a primary cause of restoration failure. Early moisture contamination on luting cements during setting results not only in an increased loss of substance but also a reduction of physical properties especially its surface hardness. Chitosan can improve the mechanical properties of GICs and decrease its solubility, therefore it is necessary to do research on the solubility, water sorption and surface hardness of the chitosan modified GICs. Aim This study was aimed to investigate the effect of addition of chitosan to the liquid of GIC on water sorption, solubility and microhardness of GIC. Materials and methods Commercially available powder/liquid restorative GIC was used in this study. A total of 60 samples were used in this study. The GIC samples was divided into samples of conventional GIC as a control (group I), GIC modified with 25% (v/v) chitosan solution (group II) and GIC modified with 50% (v/v) chitosan solution (group III). Water sorption and solubility results obtained from the difference between the weights of samples before and after immersion in an incubator and after dehydration. The samples with 6 mm diameter and 3 mm thickness were used for Vickers microhardness test. Results were subjected to analysis of variance and Tukey's test. Results The addition of chitosan to GIC may increase water sorption of GIC and decreased its solubility. The addition of chitosan to GIC significantly decreased its surface hardness. Conclusion The modification of GIC liquid with chitosan showed to be more effective in decreasing the solubility of GIC. However, the microhardness may significantly decrease with chitosan incorporation in polyacrylic acid liquid.

Radiopacity of 28 Composite Resins for Teeth Restorations.

Radiopacity is a fundamental requisite to check marginal adaptation of restorations. Our objective was to assess the radiopacity of 28 brands of light-cured composite resins and compare their radiopacity with that of enamel, dentin, and aluminum of equivalent thickness. Composite resin disks (0.2, 0.5, and 1 mm) were radiographed by the digital method, together with an aluminum penetrometer and a human tooth equivalent tooth section. The degree of radiopacity of each image was quantified using digital image processing. Wilcoxon nonparametric test was used for comparison of the mean thickness of each material. All of the materials tested had an equal or greater radiopacity than that of aluminum of equivalent thickness. Similar results for enamel were found with the exception of Durafill, which was less radiopaque than enamel (p < 0.05). All the specimens were more radiopaque than dentin, except for P90 (which was equally radiopaque) and Durafill (which was less radiopaque). The thickness of the specimens may influence the similarity to the enamel's radiopacity. All of the composite resins comply with specification #27 of the American Dental Association. The radiopacity of Amelogen Plus, Aph, Brilhiante, Charisma, Concept Advanced, Evolux X, Exthet X, Inten S, Llis, Master Fill, Natural Look, Opallis, P60, Tetric, Tph, Z100, and Z250 was significantly higher than that of enamel (p < 0.05). With these composites, it is possible to observe the boundaries between restoration and tooth structure, thus allowing clinicians to establish the presence of microleakage or restoration gap. Suitable radiopacity is an essential requisite for good-quality esthetic restorative materials. We demonstrate that only some composites have the sufficient radiopacity to observe the boundaries between restoration and tooth structure, which is the main cause of restoration failure.

Synthesis of new antibacterial quaternary ammonium monomer for incorporation into CaP nanocomposite

ObjectivesComposites are the principal material for tooth cavity restorations due to their esthetics and direct-filling capabilities. However, composites accumulate biofilms in vivo, and secondary caries due to biofilm acids is the main cause of restoration failure. The objectives of this study were to: (1) synthesize new antibacterial monomers and (2) develop nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and antibacterial monomer. MethodsTwo new antibacterial monomers were synthesized: dimethylaminohexane methacrylate (DMAHM) with a carbon chain length of 6, and dimethylaminododecyl methacrylate (DMADDM) with a chain length of 12. A spray-drying technique was used to make NACP. DMADDM was incorporated into NACP nanocomposite at mass fractions of 0%, 0.75%, 1.5%, 2.25% and 3%. A flexural test was used to measure composite strength and elastic modulus. A dental plaque microcosm biofilm model with human saliva as inoculum was used to measure viability, metabolic activity, and lactic acid production of biofilms on composites. ResultsThe new DMAHM was more potent than a previous quaternary ammonium dimethacrylate (QADM). DMADDM was much more strongly antibacterial than DMAHM. The new DMADDM–NACP nanocomposite had strength similar to that of composite control (p>0.1). At 3% DMADDM in the composite, the metabolic activity of adherent biofilms was reduced to 5% of that on composite control. Lactic acid production by biofilms on composite containing 3% DMADDM was reduced to only 1% of that on composite control. Biofilm colony-forming unit (CFU) counts on composite with 3% DMADDM were reduced by 2–3 orders of magnitude. SignificanceNew antibacterial monomers were synthesized, and the carbon chain length had a strong effect on antibacterial efficacy. The new DMADDM–NACP nanocomposite possessed potent anti-biofilm activity without compromising load-bearing properties, and is promising for antibacterial and remineralizing dental restorations to inhibit secondary caries.

A Cross-sectional Retrospective Study of Survival of Amalgam Restoration in a Nigerian Teaching Hospital

ABSTRACT Background This is a cross-sectional retrospective study on survival of amalgam restoration in a Teaching Hospital in Nigeria. There has been no study on this particular subject in Nigeria despite the fact that there is an alarming increase in dental caries and the preferred choice of treatment for over 5 decades has been amalgam restoration. Materials and methods It is a retrospective study of dental records of the dental center over a period of 12 years setting certain criteria that must be met by such records. Those that fulfilled these criteria were then recalled for examination. Results Two hundred and ninety-four amalgam restorations were placed with primary placements forming 75.69 of all restorations carried out while replacements were 24.31%. Fractured restoration was the commonest cause of failure of restoration accounting for 66% of all replacement. Ditching formed 15.5%, recurrent caries 11.6%, dislodged restoration 5.3%. While cervical overhanging amalgam was 1.6%. 25%, 50%, 75% cumulative failure rate occurs at 4.2 and 6.9 and 9.2 years respectively. While at the same time 73.2 and 19.2% of the restorations lasted for 5 and 10 years respectively. Conclusion Primary placement is the preoccupation of the dentist's in Nigeria while replacement rate is low. However, while recurrent caries is the major cause of restoration failure in economies country in Europe and America, it is not the case in this study. How to cite this article Olaleye AO. A Cross-sectional Retrospective Study of Survival of Amalgam Restoration in a Nigerian Teaching Hospital. World J Dent 2013;4(3):149-154.

Grindability of dental ceramics in the in vitro oral regime

Oral adjustments involving abrasive machining with dental handpieces and abrasive burs are the common practice in clinical dentistry. This practice dates back 7,000–9,000 years. However, the process itself is undoubtedly the least understood and most neglected in modern abrasive technology. In fact, improper operations of oral adjustments are the potential root cause of restoration failure. This paper presents a scientific approach to grindability of dental ceramics in the intro clinical oral regime using diamond burs and air-turbine dental handpieces. Multivariate analysis of variance (MANOVA) was applied to analyse the grindabilities of dental ceramics under the influence of the clinical conditions. The results show that grindability of dental ceramics in the clinical oral regime revealed different scales compared to ceramic machining in the engineering regime. The discussion includes grinding-induced problems in the oral regime, such as vibration, hearing loss, surface and subsurface damage, and thermal damage to soft tissues.

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Shear strengths of a gallium alloy bonded to human enamel following nine different surface treatments

Objective: Gallium and indium-containing alloys have demonstrated an ability to wet and bond to many types of materials including enamel. The purpose of this study was to evaluate and compare the bond strengths of a gallium-and-indium-containing alloy and a dental amalgam to human enamel surfaces. Method: A flat enamel bonding surface was created by slicing recently extracted human molars with a 180-grit diamond wheel. Cylinders of amalgam or a gallium–indium alloy were bonded to the as-cut surfaces or to as-cut surfaces that had been pumiced, air-abraded or acid-etched for various times. Before testing, samples were stored under different conditions (100% humidity, immersed in water, thermocycled). The shear-bond strength was determined using a crosshead speed of 0.1 mm min −1. Sample size was 10. Data was subjected to ANOVA and a post-hoc Tukey's test. Results: The bond strength of amalgam to enamel was zero. The bond strength of the gallium–indium alloy ranged between 6.5 MPa (10 s etch with 10% phosphoric acid) and 4.2 MPa (pumiced enamel). Acid-etching significantly increased the bond strength ( P>0.0001) The bond strength was not significantly affected by the type of mechanical surface preparation, storage conditions, thermocycling, etching times or acid concentrations. Significance: Bonding, particularly chemical bonding, suggests a greater potential for better wetting and therefore better sealing of a cavity. Since microleakage of restorations is one of the principal causes of restoration failure, materials that can bond may in turn posses enhanced resistance to microleakage and ultimately, resistance to restoration failure. The gallium–indium alloy evaluated in this study may be such an alloy.

気管食道ろう・気管空腸ろう形成術

Tracheoesophageal (TE) fistulization following pharyngolaryngectomy and tracheojejunal (TJ) fistulization following pharyngolaryngo-esophagectomy with free jejunum reconstruction for advanced hypopharyngeal and cervical esophageal cancer have been performed over the past 20 years at Kobe University Hospital.Out of 42 patients who underwent TE fistulization and 19 patients who received TJ fistulization, 32 patients (76%) and 16 patients (84%) regained voice capability with TE and TJ speech, respectively. The main causes of restoration failure were stenosis, the destruction of the TE or TJ fistula and a lack of motivation on the part of the patients. Most patients who underwent the TE or TJ procedure started speaking at 1 month postoperatively. The average values of the sustained vowel duration in the group of TE speakers and TJ speakers were 18 seconds and 11 seconds, respectively, at month. As far as the swallowing function is concerned, no regurgitation or aspiration was seen in 24 of the TE speakers (75%), with the use of bilateral esophageal muscle flaps, and in 15 of the TJ speakers (94%).