Domagoj Glavina

Heat-treated glass ionomer cement fissure sealants: retention after 1 year follow-up

OBJECTIVE The aim of this study was to assess the retention rate of glass ionomer cement (GIC) fissure sealants heated during setting time. METHODS One hundred and twelve teeth with well-delineated fissure morphology were sealed with composite resin and GIC. Composite resin (Helioseal F, Vivadent) was used in control group A (56 teeth). GIC (Fuji VII, GC) was applied using split-mouth design with conditioning in group B (26 teeth) and without surface conditioning in group C (30 teeth). GIC was heated with external heat source (Elipar Trilight, Espe) for 40 s during the setting time according to the manufacturers instructions. Fissure sealants were evaluated 1 year after clinical service. RESULTS Retention rate in group A was 80.4% after 1 year of clinical service. Group B showed retention rate of 30.8%, and group C of 26.7%. Two new caries lesions were detected in groups B and C. Significant differences in retention between the composite group and GIC groups were obtained by Kruskal-Wallis and Mann-Whitney tests. CONCLUSION It could be concluded that retention rate of GIC sealing treated with heat during setting time was significantly lower than retention of conventional composite resin. The heating procedure during setting of GIC sealants cannot be recommended as routine treatment in clinical practice.

One-Year Clinical Evaluation of a Glass Carbomer Fissure Sealant, a Preliminary Study

Glass Carbomer is a new generation of restorative material developed from glass-ionomer cements with possibility of gradual mineralization into fluorapatite. The aim of this clinical trial was to investigate the retention of Glass Carbomer fissure sealant after 12 months, in comparison to a commonly used conventional resin-based sealant. Forty-eight teeth in 24 patients [mean (SD) = 8 (2.3) years] with well-delineated fissure morphology were randomly divided into two equal groups and sealed with Bis-GMA resin-based Helioseal F (group A, Ivoclar Vivadent, Liechtenstein) and Glass Carbomer (group B, Glass Carbomer Sealant, Glass Carbomer Products, Leiden, Netherlands) using the split mouth design. Materials were placed and set according to the manufacturers instructions using a polymerization unit Bluephase 16i (Vivadent, Liechtenstein). Complete sealant retentions in both groups were 100% and 75% after 6 and 12 months of clinical service, respectively. There were there were no secondary caries lesions in both groups after 6 months; two new carious lesions were detected in both groups after 12 months. The Mann-Whitney U test revealed no significant difference between the two groups at both evaluations points (P > 0.05). Glass Carbomer material showed a similar retention rate when compared with a resin-based sealant. Future studies are required to examine the long-term performance of Glass Carbomer sealants.

Influence of Thermo-Light Curing with Dental Light-Curing Units on the Microhardness of Glass- Ionomer Cements

The purpose of this study was to verify for various glass-ionomer cement (GIC) products whether the application of thermo-light curing on the initial curing material produces an increase in microhardness, and to determine whether this hardness varies depending on the depths of the GIC samples. The efficacy of various polymerization units on this additional hardening was also examined. The GIC samples were thermo-light cured for 60 seconds with three polymerization units. The Vickers microhardness was measured at three different depths: 2 mm, 3 mm, and 4 mm. Analysis of variance and Newman-Keuls test showed statistically significant differences among tested samples for all three GIC groups (P < .001). The results of linear regression analysis showed a statistically significant relationship between the hardness of the material and the temperature for samples with depths of 2 mm (R = 0.78; P = .0028) and 3 mm (R = 0.59; P = .045). The findings of this study indicate that thermo-light curing of GIC with different polymerization units for 60 seconds during setting reaction increases the microhardness of the GICs at all depths tested and may increase resistance to mastication forces, which can be validated in future clinical studies.

Clinical evaluation of three fissure sealants: 24 month follow-up

Aim: This was to compare 3 different materials for fissure sealing (FS) after a clinical use during a 24 month period and to assess the use of flowable composite resins in combination with dentine adhesives as sealing materials. Study Design: There were 41 patients aged from 7–17 years, for whom 100 permanent molars were sealed with 3 different sealing materials. Methods: Group A, 33 teeth were sealed material Helioseal Clear Chroma (Vivadent, Schaan, Liechtenstein); Group B, 33 teeth were sealed with Teethmate F1 (Kuraray, Kurashiki, Japan), and in Group C, 34 teeth were sealed with the flowable composite Tetric Flow (Vivadent, Schaan, Liechtenstein). For the analysis of the degree of retention, the criteria used were: 0-complete retention, 1-loss of 1/3 of material, 2-loss of 2/3 of material, 3-complete loss of material. Clinical criteria for appearance of a new caries lesion included following values: Caries present (+) or caries absent (−). Statistics: Chi-Square test was used for statistical analysis of retention rates between groups. Results: After the 24 month period, the highest retention rate of complete retention was established for the material Tetric Flow of 76.5%, Helioseal Clear Croma 66.7%, and Teethmate F1 60.6%. The incidence of caries with Helioseal Clear Croma was 6.1%, for Teethmate F1 3%, with no statistically significant difference after the 24 months period (p=0.656). In the group of teeth sealed with Tetric Flow, there was not a single case of caries noted. Conclusions: The use of flowable composite resins as sealing materials is equal to other materials for fissure sealing.

Effect of different thermo–light polymerization on flexural strength of two glass ionomer cements and a glass carbomer cement

Statement of problem. Whether polymerization lights can be used for heating glass ionomer cements (GICs) or glass carbomer (GCP) to improve their mechanical properties is not well established. Purpose. The purpose of this in vitro study was to assess the effect of thermo–light polymerization on the flexural strength (FS) of 2 GICs (Fuji IX GP Fast, Ketac Molar) and a GCP. Material and methods. Specimens (n=10) were prepared in stainless steel molds (2×2×25 mm), compressed, exposed to 3 polymerization lights (500, 1000, 1200 mW/cm2) for 2 cycles of 40 seconds on each side, and stored in petroleum jelly (37°C, 24 hours). Results. Significant FS differences were detected among groups after different thermo–light polymerization regimens (F=50.926, df=11, P<.001). GCP showed the highest mean FS (˜5 times, P<.001) after thermo–light polymerization with power outputs of 1000 (127.1 ±25.8 MPa) and 1200 mW/cm2 (117.4 ±18.5 MPa), with no significance difference between them (P=.98), compared with 500 mW/cm2 (24.1 ±1.7 MPa). For Ketac Molar, compared with autopolymerization setting (15.5 ±3.1 MPa), a significant increase in mean FS (˜2.5 times) was only observed in specimens treated with 1200 mW/cm2 polymerization light (P=.03). For Fuji IX GP Fast, only the light with 1000 mW/cm2 output significantly increased the FS (98.9 ±23.4 MPa, P<.001) compared with the autopolymerization setting (34.9 ±6.4 MPa). Conclusions. Thermo–light polymerization accelerated the development of FS in the tested GICs, potentially protecting against saliva contamination during the first 3 to 4 minutes after mixing GIC. Thermo–light polymerization of the glass carbomer with power outputs of 1000 and 1200 mW/cm2 also substantially increased FS. The clinical advantages of the findings should be validated by in vivo studies.

THERMO-CURED GLASS IONOMER CEMENTS IN RESTORATIVE DENTISTRY

Numerous positive properties of glass ionomer cements including biocompatibility, bioactivity, releasing of fluoride and good adhesion to hard dental tissue even under wet conditions and easy of handling are reasons for their wide use in paediatric and restorative dentistry. Their biggest drawbacks are the weaker mechanical properties. An important step forward in improving GIC’s features is thermo-curing with the dental polymerization unit during setting of the material. Due to their slow setting characteristics the GIC is vulnerable to early exposure to moisture. After thermo curing, cements retain all the benefits of GIC with developed better mechanical properties, improved marginal adaptation, increased microhardness and shear bond strength. Adding external energy through thermocuring or ultrasound during the setting of conventional GIC is crucial to achieve faster and better initial mechanical properties. Further clinical studies are needed to confirm these findings.

The prevalence of orthodontic treatment needs of school children in northern Herzegovina

OBJECTIVE The study was conducted to evaluate the Index of Orthodontic Treatment Need based on the Dental Health Component (DHC). MATERIALS AND METHODS 300 students aged 12-15 years were included in this study. The examinations were performed in two elementary schools in the municipality of Prozor-Rama, using standard dental instruments. Children were ranked into five grades according to the DHC. RESULTS Only 12% of children were found not to have a need for orthodontic treatment. Of the others, 45.33% had a great, and 10% a very great need for orthodontic treatment. The rest of the children were found to have a need for minor or moderate orthodontic treatment. Slightly more girls than boys had a great or a very great need for treatment, although the difference by gender was not statistically significant. Analysis of the level of need by age of children showed no significant difference; children with a great need of orthodontic treatment prevailed in all age groups. About 85% of children with a great and a very great need for orthodontic treatment would agree to orthodontic treatment, while the rate of non-acceptance was about 5%. CONCLUSION The high rate of need for orthodontic treatment in the examined students is explained by the lack of programs for this type of health care, the insufficient number of qualified orthodontic specialists, and the very low percentage of allocations from the state budget for oral health.

In-vitro Study on Temperature Changes in the Pulp Chamber Due to Thermo-Curing of Glass Ionomer Cements

The application of the Glass Ionomer Cements in clinical dentistry is recommended due to properties such as fluoride release, chemical adhesion to tooth, negligible setting shrinkage, and coefficient of thermal expansion close to tooth, low creep, and good color stability. However, the cement is vulnerable to early exposure to moisture due to slow setting characteristics. The uses of external energy such as ultrasound and radiant heat (Thermo-curing) have been reported to provide acceleration of the setting chemistry and enhance physical properties. Aim: The aim of this in vitro study was to analyze temperature changes in the pulpal chamber when using radiant heat to accelerate the setting of GICs. Material and Methods:The encapsulated GIC Equia Forte was used for this study. The temperature changes in the pulp were measured using thermocouple in the cavities which were 2,6 and 4,7mm deep with and without filling. Results:The results showed that a temperature rise (ΔT) in the pulp chamber was 3,7°C. ΔT for the 2.6mm and 4.7mm deep cavity and without placing any restoration the temperature was 4,2°C and 2,6°C respectively. After the restoration has been placed, the ΔT range in the pulp chamber was lower ranging from 1.9°C to 2.4°C. Conclusion: It could be concluded that Thermo-curing of the GIC during the setting is safe for the pulp and can be recommended in clinical practice.

The effect of petroleum jelly, light-cured varnish and different storage media on the flexural strength of glass ionomer dental cements

Abstract This study determined the influence of coating with either petroleum jelly or light-cured varnish and storage medium on the flexural strength of glass-ionomer cements (GIC). The flexural strength of two glass-ionomer cements (Fuji Equia Fil and Ketac Molar Aplicap) was measured. Specimens (2 × 2 × 25 mm) were prepared in three groups: uncoated, coated with petroleum jelly, or coated with light-cured varnish (EquiaCoat) cured for 20 s using a cure lamp (Bluephase G2, Ivoclar Vivadent, Schaan, Liechtenstein). Specimens were stored for 1 week at 37 °C in water, artificial saliva or 20 mmol dm−3 lactic acid, then flexural strength was determined in 3-pont bend. Data were analyzed by ANOVA and Tukey HSD post hoc test (p < 0.05). In addition, the mold was filled with water and the temperature change caused by the cure lamp was measured with a thermocouple. For both materials, storage in water gave the lowest flexural strength. It was slightly higher in either saliva or lactic acid, and was improved by coating in petroleum jelly. Specimens coated with light-cured varnish, that also involved heating with a cure lamp, gave the highest flexural strength. The heating effect of the lamp was demonstrated by the temperature rise in the water in the mold after light exposure from 21.9 (± 1.0) °C to 26.8 (± 1.0) °C. hence, sealing of GIC from aqueous media improves flexural strength. The cure lamp emitted heat, which may enhance the flexural strength of specimens coated with light-cured varnish.