Effect of Curing Time on the Bond Strength of Orthodontic Brackets Bonded by Light Cure Resin-Modified Glass Ionomer Cement: An In vitro Evaluation

This study was designed with the aim to evaluate the effect of curing time on the shear-bond strength of orthodontic brackets bonded using light cure Resin-Modified Glass Ionomer Cements (RMGIC). This class of cement when used for luting orthodontic brackets offers certain advantages when compared to the more commonly used resin cements. Intact natural teeth (premolars) extracted for therapeutic purposes as part of orthodontic treatment was sourced for use in this study. The teeth were equally divided into four groups four testing, Group 1 - brackets bonded with RMGIC and cured for 3 seconds, Group 2 - brackets bonded RMGIC and cured for 6 seconds, Group 3 - brackets bonded with RMGIC and cured for 9 seconds and Control group - brackets bonded with composite and cured for 15 seconds. A high intensity LED light source was used to cure the cements. The Shear-Bond strength of the brackets was evaluated using a universal testing machine. One-way ANOVA test and Tukey multiple comparison tests were done to compare the difference of Shear-Bond Strengths among the groups tested. The average Shear Bond Strength among study groups was 7.64±2.86 MPa. The ANOVA and Tukey multiple comparison tests could not identify a statistically significant difference in Shear-Bond Strengths among the groups. Curing time does not appear to have a statistically significant effect on the Shear Bond Strength of orthodontic brackets bonded using Resin-Modified Glass Ionomer Cements..

Analysis of the terms of usage of non-removable restorations fixed by different glass ionomer cements

Preservation and restoration of dental health of patients is achieved by early detection and treatment of diseases, finding ways of individual prevention, detection and elimination of risk factors for their development. The amount of materials significantly increased used to restore the integrity of teeth and dentition. Among them are dental materials for permanent fixation of indirect non-removable restorations. The material is used to fill the space between the inner surface of the artificial structure and the support element. This helps to mechanically fix the restoration in place to prevent its displacement during chewing. The correct choice of dental material for permanent fixation is an important decision and will determine the long-term success of permanent restorations. The aim of the study is to analyze the durability using non-removable structures of dentures mounted on different glass ionomer cements.

Influence of Selected Restorative Materials on the Environmental pH: In Vitro Comparative Study

In dental caries treatment, it is worth using such restorative materials that may limit plaque accumulation. The pH of the filling seems to be an important factor affecting the potential bacterial colonisation. Our study aimed to assess how selected restorative materials influence the environmental pH. A total of 150 specimens (30 of each: Ketac Molar, Riva LC, Riva SC, Filtek Bulk Fill, and Evetric) were placed in 100 sterile hermetic polyethene containers with saline and stored in 37 °C. The pH of each sample was measured using the electrode Halo HI13302 (Hanna Instruments, Poland) at specific points in time for 15 days. The initial pH levels were significantly lower for glass ionomer cements (3.9–4.7) compared to composites (5.9–6.0). With time, the pH increased for samples with glass ionomer cements (by nearly 1.5), whereas it decreased for samples with composites (maximally by 0.8). In the end, all materials were in the pH range between 5.3 and 6.0. The highest final pH was obtained with Ketac Molar at about 5.9. Double samples had lower pH values than single samples, irrespective of the type of material. In conclusion, immediately after application, restorative materials decreased the environmental pH, especially light-cured glass ionomer cements. For glass ionomers, within two weeks, the pH increased to levels comparable with composites.

In Vitro Weight Loss of Dental Composite Resins and Glass-Ionomer Cements Exposed to A Challenge Simulating the Oral Intake of Acidic Drinks and Foods

Specific conditions of the oral cavity, such as intake of acidic drinks, foods, and drugs, represent a damage both for teeth as well as restorative materials. The aim of this in vitro study is to assess the influence of an acidic challenge on the weight loss of biomimetic restorative dental materials (composite resins and glass-ionomer cements, respectively). Seven products recently available in the marked have been tested in this study for the two kinds of materials, respectively. Resin composites were divided into Groups 1A–7A, whereas glass-ionomer cements into Groups 1B–7B. A total of six samples was considered for each group, among which two were stored into distilled water (control samples) whereas the other four were immersed into soft drink (Coca-Cola, Coca-Cola Company, Milano, Italy) for 7 days. Respectively, after 1, 3 and 7 days, weight was assessed for each sample and the percentage weight loss was calculated. For all the composite resins (Groups 1A–7A), no significant intergroup or intragroup differences occurred for the weight loss values (p > 0.05). Conversely, all glass-ionomers (Groups 1B–7B) showed a significant and progressive weight loss after 1, 3, and 7 days of acid challenge (p < 0.05) (intragroup differences). This reduction was significantly lower in case of GC Equia Forte + Coat and ChemFil Rock, with respect to the other cements (p < 0.05) (intergroup differences). In conclusions, all the biomimetic composite resins showed a reliable behavior when exposed to acidic erosion, whereas glass-ionomers cements generally tended to solubilize. However, the additional use of a protective layer above these latter materials could reduce this event. Despite these results appear to be interesting from a clinical point of view, future morphological evaluations should be conducted to evaluate the superficial changes of the materials after acidic explosion.

Bond Strength of Self-Adhesive Flowable Composites and Glass Ionomer Cements to Primary Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies

Background: Conventional composites are largely used in pediatric restorative dentistry and demonstrate successful clinical outcomes. However, the need for simplification of operative steps in young or uncooperative children demands reliable alternatives. Therefore, the aim of the present systematic review and meta-analysis was to evaluate the in vitro bond strength of glass ionomer cements (GICs) and self-adhesive flowable composites (SFCs) on deciduous teeth. Methods: A comprehensive literature search according to the PRISMA checklist was manually and electronically performed by two independent reviewers through the following databases: MEDLINE/PubMed, Google Scholar, Scopus, and Embase, to include in vitro studies comparing GICs and SFCs bond strength values of restorations on primary teeth. In addition, three groups of meta-analyses were conducted using random-effects models. Results: Three articles meeting the inclusion criteria were selected and subjected to both qualitative and quantitative assessment. No statistically significant difference was found between SFC versus GIC; however, both groups significantly differed with conventional flowable composites (CFs). Conclusions: Despite the absence of significant difference in bond strength values, SFCs may be considered a valid alternative to GICs in the restoration of deciduous teeth, although CFs proved better in vitro performances.