Margin Integrity and Secondary Caries of Lined or Non-lined Composite and Glass Hybrid Restorations After Selective Excavation In Vitro

Effect of radiotherapy on the surface roughness and microhardness of contemporary bioactive restorative materials

OBJECTIVE

The aim of this in vitro study was to evaluate the effect of radiotherapy on the surface microhardness and roughness of different bioactive restorative materials.

MATERIALS AND METHODS

A total of 60-disc specimens (5 mm × 2 mm) were performed in four groups (n = 15 each) from Equia Forte HT, Cention N, Activa Bioactive Restorative, and Beautifil II. Following the polishing procedure (600, 1000, 1200 grit silicon carbide papers), all specimens were irradiated at 2 Gy per fraction, five times a week for a total dose of 70 Gy in 30 fractions over 7 weeks. Before and after the irradiation, the specimens were analyzed regarding the surface roughness and microhardness. Surface morphology was also analyzed by scanning electron microscopy. Kruskal-Wallis test, Wilcoxon test, and paired sample t-test were used for statistical analysis.

RESULTS

Significant differences were found after radiation with increased mean roughness of both Cention N (p = 0.001) and Beautifil II (p < 0.001) groups. In terms of microhardness, only the Beautifil II group showed significant differences with decreased values after radiation. There were statistically significant differences among the groups' roughness and microhardness data before and after radiotherapy (p < 0.05).

CONCLUSION

The effect of radiotherapy might differ according to the type of the restorative material. Although results may differ for other tested materials, giomer tends to exhibit worse behaviour in terms of both surface roughness and microhardness.

CLINICAL RELEVANCE

In patients undergoing head and neck radiotherapy, it should be taken into consideration that the treatment process may also have negative effects on the surface properties of anti-caries restorative materials.

Pulp vitality of primary molars with deep caries treated with ART restorations: 2-year RCT

The aim of this study was to compare the pulp vitality of primary teeth with deep caries treated with two restorative techniques. The restoration survival rate was also evaluated as a secondary outcome. Children aged from 4 to 8 years with at least one deep carious lesion in molars were selected at the Ibirapuera University dental clinic. One hundred and eight deciduous molars were allocated into two groups: (1) restoration with calcium hydroxide cement lining followed by filling with high-viscosity glass ionomer cement (CHC+HVGIC) or (2) restoration with HVGIC. Pulp vitality and restoration survival were evaluated at 6, 12, and 24 months. Intent-to-treat analysis was used for pulp vitality, and survival analysis was performed with the Kaplan-Meier method (α=5%). Results: At 24 months, 86 restorations were evaluated, and 91 were evaluated at least once during the study. There was no significant difference between the restorative treatments regarding pulp vitality (CHC +HVGIC=70% and HVGIC=68.5%) (OR=1.091; CI95%=0.481-2.475). However, HVGIC (73%) restorations showed a higher survival rate than CHC+HVGIC (50%) (p=0.021). Thus, it can conclude that deep caries in primary molars should be restored with HVGIC, since the technique results in similar pulp vitality to the CHC +HVGIC, but with a higher restoration survival rate.

A Contemporary Evaluation on Posterior Direct Restoration Teaching among Undergraduates in Dental Schools in Malaysia

There is a current trend to restore posterior teeth with composite resin due to increasing demands on natural tooth colour restoration and increased concern about the safety of amalgam restorations. The objective was to evaluate the current teaching of posterior direct restoration among restorative dental lecturers in Malaysia compared to available international literature. An online questionnaire, which sought information on the teaching of posterior restoration was developed and distributed to 13 dental schools in Malaysia. The response rate for the questionnaire was 53.8%. The most popular posterior restoration teaching methods among the respondents were lecture (95.7%), demonstration (87.0%) and problem-based learning (PBL) (73.9%), while continuous assessment and a practical competency test (82.6%) were the most popular assessment methods. Placing a hard setting calcium hydroxide and GIC base for deep cavity restored by composite restoration was taught in 79.2% of cases. The standard protocols for posterior composite restoration were incremental filling in deep cavity (87.5%), using circumferential metal bands with wooden wedge (91.7%), with a total etch system (95.8%), using a light emitting diode (LED) light curing unit (91.7%), finishing using water cooling (80%) and finishing with a disc (87.5%). Graduates from dental schools in Malaysia received similar theoretical, preclinical and clinical teaching on posterior restoration techniques, although there were variations in the delivery methods, techniques and assessments, pointing to a need for uniformity and consensus.

Evaluation of the bond strengths of restorative materials to primary tooth dentin treated with different pulpotomy techniques

The aim of this study was to investigate the changes of different pulpotomy techniques on the primary tooth dentin and to evaluate the effects of these pulpotomy methods on the shear bond strength of restorative materials to primary tooth dentin. Two hundred and forty dentin specimens were distributed randomly to the study groups as; control, ferric sulphate, Biodentine® , Nd:YAG laser, photobiomodulation, and atmospheric pressure cold plasma (APCP). After the application of pulpotomy methods, samples were again randomly divided to two restorative materials (glass hybrid and composite resin) (n = 20) and shear bond strength (SBS) test was performed. Then, 12 new dentin specimens were prepared for all groups for surface analysis. Surface examination (n = 12) and fracture analyses (n = 240) were carried out with scanning electron microscope (SEM). Statistical significance range was accepted as α <.05 for all data. A statistically significant difference was obtained among all study groups for glass hybrid material as well as composite material (p <.05). While the highest mean SBS value was obtained with Nd:YAG laser (7.58 ± 0.60 MPa), the lowest value was observed with Biodentine® (6.70 ± 0.91 MPa; p = .001) for glass hybrid material. For composite material, the highest mean SBS value was calculated for Nd:YAG laser (13.79 ± 1.24 MPa), while the lowest value was obtained with ferric sulphate (10.17 ± 1.45 MPa; p = .001). Fracture modes were mainly adhesive and mixed type according to SEM analysis. Moreover, morphological changes were observed with SEM on the dentin surfaces of ferric sulphate, Biodentine® and Nd:YAG laser. Within the limitations of this study, Nd:YAG laser increased the shear bond strength values in groups of composite resin. RESEARCH HIGHLIGHTS: In this article, we report the results of the shear bonding strength test of two restorative materials (glass-hybrid vs. composite resin) to primary tooth dentin following the application of five different pulpotomy techniques (ferric sulfate, Biodentine® , Nd:YAG laser, photobiomodulation, and atmospheric pressure cold plasma) were reported. This article will contribute to the literature that there are considerably limited researches concerning the bond strength of glass hybrid to primary dentin and also atmospheric pressure cold plasma in pulpotomies. The SEM examination was performed in two stages in this study; the morphological changes in both treated dentin surfaces and the surfaces of the samples subjected to the shear bond strength test.

Efficacy of GC Gold Label 9 and GC Miracle Mix® Restorations using Atraumatic Restorative Treatment (ART) in Rural Settings: A Randomized Controlled Trial

Objectives: This study compared the longevity of high strength posterior glass ionomer and metal-reinforced glass ionomer using ART in rural settings within an 18-month observation period. Study Design: A nonblinded parallel design randomized controlled trial was conducted among children who attended dental outreach programs in a rural area of Southern India. Atraumatic Restorative Treatment (ART) was performed in 92 permanent posterior teeth with either high strength posterior glass ionomer or metal-reinforced glass ionomer restorations. The allocation ratio was 1:1. Restorations were evaluated at 1, 6, 12 and 18 months after placement. Results: The success rate of metal-reinforced glass ionomer restorations was 100%, 95.4%, 90.4% and 87.2% as compared to high strength posterior glass ionomer whose success rates were 100%, 93%, 85% and 61.8% at the four follow ups respectively. There was a statistically significant difference between the success rate of the two materials at the end of 18 months with the metal-reinforced glass ionomer restorations having a higher success rate (p=0.015). Conclusions : Although the clinical performance of both materials were largely similar, the metal-reinforced glass ionomer restorations had a higher success rate than the conventional GIC at the end of 18 months of follow-up.

Clinical Performance of a Glass Hybrid Restorative in Extended Size Class II Cavities

Objective:

To evaluate the clinical performance of a glass hybrid restorative compared with a resin composite in the restoration of large and deep Class II cavities after 24 months.

Methods and Materials:

A total of 108 extended size, with the width of the proximal box not interfering with the peak of the cusps and the proximal box in occlusion, Class II lesions in 37 patients were either restored with a glass hybrid restorative or with a micro-hybrid composite resin in combination with selective etching by two experienced operators according to the manufacturer's instructions. Two independent examiners evaluated the restorations at baseline and at the six-, 12-, 18-, and 24-month recalls according to the modified US Public Health Service criteria. Negative replicas at each recall were observed under scanning electron microscopy (SEM) to examine surface characteristics. Data were analyzed statistically.

Results:

After 24 months, 90 restorations were evaluated in 32 patients (recall rate: 86.5%). Four glass hybrid restorations were missing; three were due to bulk and one was due to proximal fracture at 12 months. Only six restorations were scored as bravo at baseline and at the six-, 12-, 18-, and 24-month recalls for color (p&lt;0.05). No significant differences were observed between the two restorative materials for the other criteria evaluated (p&gt;0.05). SEM observations exhibited acceptable surface and marginal adaptation characteristics for both restorative materials at 24 months.

Conclusions:

Although glass hybrid restorations showed significant mismatch in color, both restorative materials exhibited successful performance for the restoration of large Class II cavities after 24 months.

Thermo-setting glass ionomer cements promote variable biological responses of human dental pulp stem cells

OBJECTIVE

To evaluate the in vitro cytotoxicity of Equia Forte (GC, Tokyo, Japan) and Ionostar Molar (Voco, Cuxhaven, Germany) on human dental pulp stem cells (hDPSCs).

METHODS

hDPSCs isolated from third molars were exposed to several dilutions of Equia Forte and Ionostar Molar eluates (1/1, 1/2 and 1/4). These eluates were obtained by storing material samples in respective cell culture medium for 24h (n=40). hDPSCs in basal growth culture medium were the control. Cell viability and cell migration assays were performed using the MTT and wound-healing assays, respectively. Also, induction of apoptosis and changes in cell phenotype were evaluated by flow cytometry. Changes in cell morphology were analysed by immunocytofluorescence staining. To evaluate cell attachment to the different materials, hDPSCs were directly seeded onto the material surfaces and analyzed by scanning electron microscopy (SEM). The chemical composition of the materials was determined by energy dispersive X-ray (EDX) and eluates were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). Statistical analysis was performed with analysis of variance (ANOVA) and Student's t-test (α<0.05).

RESULTS

Undiluted Equia Forte extracts led to a similar cell proliferation rates than the control group from 72h onwards. There were no significance differences between Equia Forte and Ionostar Molar in terms of cell apoptosis and phenotype. However, in presence of Equia extracts the migration capacity of hDPSCs was higher than in presence of Ionostar Molar (p<0.05). Also, SEM studies showed a higher degree of cell attachment when Equia Forte extracts were used. Finally, EDX analysis pointed to different weight percentages of C, O and Ca ions in glass ionomer cements, while other elements such as La, Al, Si, W, Mo and F were also detected.

SIGNIFICANCE

In summary, Equia Forte promoted better biological responses in hDPSCs than Ionostar Molar.

Randomized clinical trial of encapsulated and hand-mixed glass-ionomer ART restorations: one-year follow-up

Objective

This prospective, randomized, split-mouth clinical trial evaluated the clinical performance of conventional glass ionomer cement (GIC; Riva Self-Cure, SDI), supplied in capsules or in powder/liquid kits and placed in Class I cavities in permanent molars by the Atraumatic Restorative Treatment (ART) approach.

Material and Methods

A total of 80 restorations were randomly placed in 40 patients aged 11-15 years. Each patient received one restoration with each type of GIC. The restorations were evaluated after periods of 15 days (baseline), 6 months, and 1 year, according to ART criteria. Wilcoxon matched pairs, multivariate logistic regression, and Gehan-Wilcoxon tests were used for statistical analysis.

Results

Patients were evaluated after 15 days (n=40), 6 months (n=34), and 1 year (n=29). Encapsulated GICs showed significantly superior clinical performance compared with hand-mixed GICs at baseline (p=0.017), 6 months (p=0.001), and 1 year (p=0.026). For hand-mixed GIC, a statistically significant difference was only observed over the period of baseline to 1 year (p=0.001). Encapsulated GIC presented statistically significant differences for the following periods: 6 months to 1 year (p=0.028) and baseline to 1 year (p=0.002). Encapsulated GIC presented superior cumulative survival rate than hand-mixed GIC over one year. Importantly, both GICs exhibited decreased survival over time.

Conclusions

Encapsulated GIC promoted better ART performance, with an annual failure rate of 24%; in contrast, hand-mixed GIC demonstrated a failure rate of 42%.