Resin-modified Glass Ionomer Restorations Research Articles

Assessment of Bioactive Resin-Modified Glass Ionomer Restorative as a New CAD/CAM Material. Part I: Marginal Fitness Study

The objective of this in vitro study was to evaluate and compare the marginal fitness of monolithic crowns fabricated from a newly developed bioactive CAD/CAM resin block and reinforced resin CAD/CAM block pre-and post-cementation with adhesive and self-adhesive resin cements. Bioactive CAD/CAM block were fabricated from ACTIVA BioACTIVE-RESTORATIVE (Pulpdent Corporation, USA) using a clear rectangular Teflon mold. Thirty-two human maxillary first premolar teeth were prepared to receive full crowns then divided into two main groups of 16 teeth each according to the type of block used to fabricate the crowns: Group A: crowns fabricated from the bioactive resin block, Group B: crowns fabricated from reinforced composite block (BRILLIANT Crios, Coltene). Each group was then subdivided into two subgroups according to the type of resin cement used for cementation, Subgroups (A1, B1): RelyX Ultimate cement, Subgroups (A2, B2): ACTIVA BioACTIVE-cement. The prepared teeth were scanned using CEREC Omnicam digital intra-oral and the crowns were then designed using CEREC Premium software (version 4.4.4) and milled using CEREC MC XL milling unit. The marginal gap of each crown was measured before cementation at four points on each tooth surface using a digital microscope at a magnification of 230x. Each crown was then cemented on its respective tooth according to the manufacturers’ instructions of each cement, and the marginal gap was measured again at the same aforementioned points. The results of this study showed that the marginal gap of all groups are below the clinically acceptable limit. Meanwhile, the marginal gap of the crowns fabricated from both block types increased significantly after cementation with both types of cement. Pre-cementation, student’s t-test revealed that there is no statistically significant difference in the marginal gap of crowns fabricated from both block types (p> 0.05). Post-cementation, a statistically highly significant difference was seen between both block types with both types of cement (p<0.01). From the results of this study, the newly developed bioactive resin block seems a promising material for CAD/CAM applications in terms of marginal fitness.

Influence of desensitizing agents in management of noncarious cervical lesion and bonded restorations: A preliminary 12-week report.

Objectives:The primary objective of this study was to investigate the effectiveness in reducing dentin hypersensitivity in noncarious cervical lesions (NCCLs) by home-based desensitizing toothpaste (TP), in-office Gluma desensitizer application, and resin-modified glass-ionomer cement (RMGIC) restoration. The secondary objective was to evaluate the long-term outcome of the glass-ionomer cement restoration following the application of bioactive glass-containing desensitizer TP.Materials and Methods:A total of 73 patients or 151 teeth were included in the study and randomly allotted to one of the four different treatment groups. Pre- and postoperative symptom and air-blast/tactile sensitivity scores were recorded for statistical analysis. Postoperative sensitivity was analyzed at 1, 4, and 12 weeks after treatment. Nonparametric statistical tests were employed.Results:Kruskal–Wallis test noted a significant reduction in postoperative sensitivity at all time periods with the RMGIC group compared to other treatment options. Significantly higher patient dropout was observed in desensitizing TP regimen.Conclusions:This interim 12-week report on dentin hypersensitivity management of NCCLs concludes that resin-modified glass-ionomer restoration was able to achieve a significant instant reduction in sensitivity and patient satisfaction compared to other noninvasive at-home and in-office procedures.Clinical relevance:This interim 12-week report on dentin hypersensitivity management of noncarious cervical lesions concludes that resin-modified glass-ionomer restoration was able to achieve a significant reduction in sensitivity, and patient satisfaction was higher compared to other noninvasive at-home and in-office procedures.

Detection of Caries Around Resin-Modified Glass Ionomer and Compomer Restorations Using Four Different Modalities In Vitro.

The aim of this study was to evaluate the ability of visual examination (International Caries Detection and Assessment System—ICDAS II), light-emitting diodes (LED) fluorescence (SPECTRA), laser fluorescence (DIAGNODent, DD), photothermal radiometry and modulated luminescence (PTR-LUM, The Canary System, CS) to detect natural decay beneath resin-modified glass ionomer (RMGIC) and compomer restorations in vitro. Twenty-seven extracted human molars and premolars, consisting of 2 control teeth, 10 visually healthy/sound and 15 teeth with natural cavitated lesions, were selected. For the carious teeth, caries was removed leaving some carious tissue on one wall of the preparation. For the sound teeth, 3 mm deep cavity preparations were made. All cavities were restored with RMGIC or compomer restorative materials. Sixty-eight sites (4 sites on sound unrestored teeth, 21 sound sites and 43 carious sites with restorations) were selected. CS and DD triplicate measurements were done at 2, 1.5, 0.5, and 0 mm away from the margin of the restoration (MOR). SPECTRA images were taken, and two dentists provided ICDAS II scoring for the restored surfaces. The SPECTRA data and images were inconclusive due to signal interference from the restorations. Visual examinations of the restored tooth surfaces were able to identify 5 of the 15 teeth with caries. In these situations, the teeth were ranked as having ICDAS II 1 or 2 rankings, but they could not identify the location of the caries or depth of the lesion. CS and DD were able to differentiate between sound and carious tissue at the MOR, but larger variation in measurement, and poorer accuracy, was observed for DD. It was concluded that the CS has the potential to detect secondary caries around RMGIC and compomer restorations more accurately than the other modalities used in this study.

Linear Coefficient of Thermal Expansion Evaluation of Glass Ionomer and Resin-Modified Glass Ionomer Restorative Materials.

The purpose of this evaluation was to evaluate the linear coefficient of thermal expansion (LCTE) of 12 conventional glass ionomer (GIC) and four resin-modified glass ionomer (RMGI) restorative materials. GIC and RMGI specimens (2 mm × 5 mm × 5 mm) were fabricated (n=12) following manufacturer instructions and were placed in 0.2M phosphate-buffered saline and stored at 37°C and 98% humidity for one week. Specimens had LCTE determined with a thermomechanical analysis (TMA) unit using a 15°C-50°C heating cycle as well as a 50°C-15°C cooling cycle at a 5°C/min rate, using a 3-mm ball-point probe under 0.02 N probe pressure with all specimens kept saturated with PBS using a specially designed quartz container. Each specimen was tested three times, with the mean representing the specimen LCTE. Mean results between specimen heating and cooling were compared with paired Wilcoxon sign rank test, while results between materials were compared with Kruskal-Wallis/Dunn's ( α=0.05). GIC LCTE ranged from approximately 5°C to 20°C ppm °K-1, while the RMGI LCTE ranged from approximately 25°C to 47°C ppm °K-1. With some exception, the LCTE during cooling displayed a greater trend. Under moisture conditions similar to the oral cavity, GIC materials overall had LCTE values closer to that reported for tooth structure. RMGI materials displayed higher values, which was thought to be related to the amount of resin in the matrix. A generally greater LCTE trend with cooling for all materials was noted, but the small magnitude of the difference is presently thought to be of minor clinical significance.

Fluoride release and recharge of enhanced resin modified glass ionomer at different time intervals

AimTo investigate the fluoride release and recharge from two fluoride releasing materials at different time intervals. Materials and methodsSixty specimens were prepared then equally divided into 12 groups (n = 5/group), representing materials used; one resin modified glass ionomer restoration (RMGI); Fuji II LC and one enhanced RMGI; ACTIVA Bioactive-Restorative. Each material was evaluated for its fluoride release before and after fluoride recharge using a topical fluoride recharging gel at 1, 2, 7, 14, 21 and 28 days. ResultsThere was a statistical significant difference between different tested time intervals regarding fluoride release before and after fluoride recharge for both tested materials, where (p ≤ 0.001). The highest mean value of fluoride release was in (Day-1), and the least mean value of fluoride release was in (Day-28). There was no statistical significant difference between both materials at each time interval regarding fluoride release before recharge. While after fluoride recharge; RMGI (Fuji II LC) showed higher fluoride release mean values compared to the enhanced RMGI (ACTIVA) at each time interval (1, 2, 7, 14, 21, 28 days). ConclusionRMGI and enhanced RMGI, showed the same pattern of fluoride release in deionized water, but RMGI was more successful to be recharged.

Treatment of gingival recession by coronally advanced flap in conjunction with platelet-rich fibrin or resin-modified glass-ionomer restoration: A clinical study.

Aims:The aim of this study is to compare the outcome of coronally advanced flap (CAF) along with the use of platelet-rich fibrin (PRF) versus CAF in conjunction with a resin-modified glass-ionomer cement (RmGIC) for the management of Millers Class I and Class II gingival recession coupled with noncarious cervical lesions (NCCLs).Materials and Methods:Single and multiple Miller's Class I and Class II gingival recessions were chosen for the study. Twenty participants with total of 78 sites associated with NCCL bilaterally in the anterior and premolar region of maxilla were selected. Thirty-nine sites were treated with CAF and PRF and the remaining 39 sites were treated with CAF and RmGIC. Clinical parameters such as probing pocket depth, relative gingival recession, relative clinical attachment level, NCCL height, NCCL width, width of keratinized tissue, and keratinized tissue thickness were measured at baseline, 90th, and 180th day in both the groups. The presence or absence of dentin sensitivity (DS) was determined at baseline and 180th day.Results:Both the groups showed optimal root coverage, with statistical significant difference in thickness of keratinized gingiva in Group I when compared to Group II from baseline to 90th day and from baseline to 180th day and also from 90th to 180th day. On comparing the DS between Group I and Group II from baseline to 180th day, Group II showed greater reduction in dentinal hypersensitivity as compared to Group I.Conclusion:The use of PRF along with CAF showed increased thickness of the keratinized tissue and the utilization of RmGIC resulted in decreased DS. Hence, the combination of CAF and PRF or CAF and RmGIC could provide a better treatment option in the management of gingival recession that is of esthetic concern.

No additional benefit of using a calcium hydroxide liner during stepwise caries removal: A randomized clinical trial

BackgroundClinicians often use calcium hydroxide liners during stepwise treatment of advanced caries. In this randomized clinical trial, the authors compared the short-term outcome of stepwise caries removal with and without use of a calcium hydroxide liner in conjunction with provisional resin-modified glass ionomer (RMGI) restorations. MethodsThe authors included in the trial 98 patients aged 15 to 30 years who had a deep carious lesion in a posterior tooth. The authors measured the dentin thickness radiographically and recorded its color, consistency, and moisture, as well as the bacterial count of the lesions. After partial caries removal, the authors assigned patients randomly to have their caries provisionally restored using RMGI with (control group) or without (test group) a calcium hydroxide liner. The primary outcome measure was tooth vitality after 90 days. Secondary outcomes included changes in dentinal, radiographic, and microbiological characteristics of the lesions. ResultsThe authors found no statistically significant difference between the test and control groups in tooth vitality after 90 days. Irrespective of calcium hydroxide liner use, the authors observed darker, harder, drier, and less contaminated dentin after the provisional restorations, but dentin thickness remained unchanged. ConclusionsOn the basis of this 3-month clinical trial’s results, the use of a calcium hydroxide liner during stepwise caries excavation and provisional restoration did not provide any additional benefit. Practical ImplicationsAfter 3 months, using a calcium hydroxide liner does not appear to offer any additional benefit when clinicians use RMGI provisional restorations during stepwise caries removal. Longer studies are needed to confirm these results.

Strengths of additions to composite or resin-modified glass-ionomer

ObjectivesAdding a new layer of material to cured resin-based composite (RBC) or resin-modified glass ionomer (RMGI) restorations is necessary in dental practice. This study investigated strengths of additions to the two materials. Material and methodsBeam-shaped specimens were made from monolithic RBC or RMGI, or additions of RBC and RMGI onto RBC or RMGI half-bar substrates. For the additions, the substrates were left undisturbed or were ground with silicon carbide paper followed by the application of a self-etch adhesive. Sample size was 10. Flexural strengths were determined by a 4-point bending test in a universal testing machine. Results were statistically analyzed with one-way ANOVA followed by Student–Newman–Keuls post-hoc test (α=0.05). ResultsFlexural strength of the monolithic RBC (86.7±21.8MPa) was significantly higher than RMGI (52.6±13.1MPa). Addition of RBC to cured RBC significantly reduced flexural strength regardless of the substrate surface conditions (34.1±11.5–45.7±21.1MPa). Addition of RMGI to cured RMGI did not significantly reduce flexural strength (36.2±8.4–52.7±25.2MPa). Flexural strength of RBC added onto cured RMGI that was ground and bonded was the lowest (21.5±10.0MPa). Most specimens from this group exhibited adhesive failure. ConclusionsRBC/RBC additions reduced flexural strength whereas flexural strength of RMGI/RMGI additions was not significantly lower than its cohesive strength. RBC added onto RMGI in the sandwich restorative configuration had lowest failure strength.

Effective Expansion

The purpose of this study was to investigate the relationship between hygroscopic expansion and polymerization shrinkage for compensation of polymerization shrinkage stresses in a restored tooth. One resin-modified glass-ionomer (RMGI) (Ketac Nano, 3M ESPE), 2 compomers (Dyract, Dentsply; Compoglass, Ivoclar), and a universal resin-based composite (Esthet•X HD, Dentsply) were tested. Volumetric change after polymerization (“total shrinkage”) and during 4 wk of water storage at 37°C was measured using an optical method (n = 10). Post-gel shrinkage was measured during polymerization using a strain gauge method (n = 10). Extracted human molars with large mesio-occluso-distal slot preparations were restored with the tested restorative materials. Tooth surfaces at baseline (preparation), after restoration, and during 4 wk of 37°C water storage were scanned with an optical scanner to determine cuspal flexure (n = 8). Occlusal interface integrity was measured using dye penetration. Data were analyzed using analysis of variance and post hoc tests (significance level 0.05). All tested materials shrunk after polymerization. RMGI had the highest total shrinkage (4.65%) but lowest post-gel shrinkage (0.35%). Shrinkage values dropped significantly during storage in water but had not completely compensated polymerization shrinkage after 4 wk. All restored teeth initially exhibited inward (negative) cuspal flexure due to polymerization shrinkage. Cuspal flexure with the RMGI restoration was significantly less (–6.4 µm) than with the other materials (−12.1 to −14.1 µm). After 1 d, cuspal flexure reversed to +5.0 µm cuspal expansion with the RMGI and increased to +9.3 µm at 4 wk. After 4 wk, hygroscopic expansion compensated cuspal flexure in a compomer (Compoglass) and reduced flexure with Dyract and resin-based composite. Marginal integrity (93.7% intact restoration wall) was best for the Compoglass restorations and lowest (73.1%) for the RMGI restorations. Hygroscopic expansion was more effective in compensating shrinkage stress than would be assumed based on total shrinkage, because only post-gel shrinkage needed compensation. Effective expansion is therefore hygroscopic expansion minus post-gel shrinkage.

Effect of two prophylaxis methods on marginal gap of Cl Vresin-modified glass-ionomer restorations.

Background. This study evaluated the effect of two prophylaxis techniques on the marginal gap of CI V resin-modified glass-ionomer restorations.Methods. Standard Cl V cavities were prepared on the buccal surfaces of 48 sound bovine mandibular incisors in this in vitro study. After restoration of the cavities with GC Fuji II LC resin-modified glass-ionomer, the samples were randomly assigned to 3 groups of 16. In group 1, the prophylactic procedures were carried out with rubber cup and pumice powder and in group 2 with air-powder polishing device (APD). In group 3 (control), the samples did not undergo any prophylactic procedures. Then the marginal gaps were measured. Two-way ANOVA was used to compare marginal gaps at the occlusal and gingival margins between the groups. Post hoc Tukey test was used for two-by-two comparisons. Statistical significance was set at P < 0.05.Results. There were significant differences in the means of marginal gaps in terms of prophylactic techniques (P < 0.001), with significantly larger marginal gaps in the APD group compared to the pumice and rubber cup group, which in turn exhibited significantly larger marginal gaps compared to the control group (P < 0.0005). In addition, the means of marginal gaps were significant in terms of the margin type (P < 0.001), with significantly larger gaps at gingival margins compared to the occlusal margins (P < 0.0005).Conclusion. The prophylactic techniques used in this study had a negative effect on the marginal gaps of Cl V resin-modified glass-ionomer restorations.

CLINICAL EVALUATION OF SELF-ADHERING FLOWABLE COMPOSITE IN NON-CARIOUS CERVICAL LESIONS

Introduction: The clinical management of non-carious cervical lesions is a challenge concerning restoring procedures because the lesions have non-retentive cavity shape and margins lying on dentin or cementum which are unfavorable for bonding. Objective: To evaluate the clinical performance of two self-adhering flowable composites compared with flowable composite and resin modified glass ionomer in restoration of non-carious cervical lesions for 1 year. Materials and Method: A total of 60 non-carious cervical lesions (15 for each material) were restored with self-adhering resin flowable composites (VertiseTM Flow and FusioTM Liquid Dentin), flowable composite with ExciTE F dental adhesive system and resin modified glass ionomer. The outer surface of the dentinal wall was roughened with a water-cooled high-speed diamond bur. Occlusal or incisal enamel margins were beveled, and no mechanical retention was performed. The restorations were re-evaluated with the modified United States Public Health Services (USPHS) criteria at baseline, 3, 6 and 12 months. Results: After 1 year, 14 of the 15 Vertise Flow and 12 of the 15 Fusio Liquid Dentin restorations were in a clinically unacceptable condition due to retention failure. The success rates of Vertise Flow (6.7%) and Fusio Liquid Dentin (20%) were less when compared to the success rate (80%) for the 2-step etch and rinse/Flowable composite and (60%) for the resin modified glass ionomer restorations (P-value < 0.001) Conclusion: The clinical performance of the self-adhering resin flowable composites showed higher failure rate than other restorative materials after 1 year of clinical use.

Setting Reaction of Dental Resin-Modified Glass Ionomer Restoratives as a Function of Curing Depth and Postirradiation Time

Specular reflectance Fourier transform infrared (SR-FTIR) spectroscopy was used to study the setting reaction of dental resin-modified glass ionomer (RMGI) restoratives as a function of curing depth and postirradiation time. Two light-cure and one tri-cure RMGI materials were selected and used according to the manufacturers’ instructions. Samples were prepared by filling the mixed materials into custom-made molds and then light-irradiating using a dental curing light. The degree of conversion and the extent of acid-base reaction of the materials at different depths (0, 1, 2, and 4 mm) and postirradiation times (10 min, 1 day, and 7 days) were determined using SR-FTIR spectroscopy in conjunction with the Kramers-Kronig (K-K) transformation. The setting reaction was also investigated using microhardness measurements. The results showed that the depth of cure increased over time by the continuous acid-base reaction rather than photopolymerization or chemical polymerization. Microhardness tests seemed less suitable for studying the setting reaction as a function of postirradiation time, probably due to softening from the humidity. Analysis using specular reflectance in conjunction with the K-K algorithm was an easy and effective method for monitoring the setting reaction of dental RMGI materials.

Comparative evaluation of microleakage of nano-filled resin-modified glass ionomer: An in vitro study.

Objective:This in vitro study evaluated the microleakage of a nano-filled resin-modified glass ionomer and a high viscosity glass-ionomer restorations in class V cavities.Materials and Methods:Thirty-two class V cavities prepared on the buccal and lingual surfaces of 16 sound, third molar teeth were randomly assigned into two groups and restored by one of the glass ionomer material; Group A: A high viscosity (Ketac Molar, 3M ESPE) Group B: A nano-filled resin-modified (Ketac N100, 3M ESPE) glass ionomer. One clinician prepared all the cavities. The materials were used according to the manufacturers’ recommendations. The restored teeth were then stored in distilled water at 37°C for 24 h, thermocycled at 5-55°C for 1000 cycles. The specimens were immersed in aqueous solution of Indian ink dye for 48 h at room temperature. They were embedded in resin polyester and sectioned longitudinally in a buccolingual direction. Microleakage was assessed according to the depth of dye penetration along the restoration. The extent of dye penetration at the occlusal and gingival margins was assessed using a stereo microscope. Randomly selected samples from each group were prepared for scanning electron microscope evaluation. The data were statistically analyzed with Friedman and Wilcoxon signed ranks tests.Results:There were statistically significant differences between the microleakage scores of the two groups for both occlusal and gingival scores (P = 0.001). Occlusal and gingival scores for high viscosity glass ionomer (P = 0.024) and nanoionomer (P = 0.021) using Wilcoxon signed ranks tests showed statistically significant differences. High viscosity glass ionomer showed significantly less microleakage compared to the nano-filled resin-modified glass-ionomer (RMGIs) at occlusal margin (P = 0.001). No significant differences were found between the groups at gingival margin (P = 0.0317).Conclusion:Within the limitations of this in vitro study, nano-filled RMGIs restorations did not perform better than high viscosity glass ionomer in class V cavities in terms of microleakage assessment.

Comparison of Micro-Leakage from Resin-Modified Glass Ionomer Restorations in Cavities Prepared by Er:YAG (Erbium-Doped Yttrium Aluminum Garnet) Laser and Conventional Method in Primary Teeth.

In recent years, significant developments have been taking place in caries removal and cavity preparation using laser in dentistry. As laser use is considered for cavity preparation, it is necessary to determine the quality of restoration margins. Glass ionomer cements have great applications for conservative restoration in the pediatric field. The purpose of this in vitro study was to compare resin-modified glass ionomer restorations micro-leakage in cavities prepared by Er:YAG (Erbium-Doped Yttrium Aluminum Garnet) laser irradiation and conventional method in primary teeth. This was an in vitro experimental study. Forty primary canine teeth were divided into 2 groups: group 1 represented cavities prepared by the no. 008 diamond bur, group 2 represented cavities prepared by Er:YAG laser. After cavity preparation, samples were restored by resin-modified glass ionomer. The teeth were thermocycled for 700 cycles, placed in 2% methylene blue for 24h and sectioned in the buccolingual direction. The degree of dye penetration was scored by 3 examiners. Data was analyzed using Mann-Whitney Test. There was no statistical difference in micro-leakage between the two modes of cavity preparation (P=0.862) CONCLUSION: Since preparing conservative cavities is very important in pediatric dentistry, it is possible to use Er:YAG laser because of its novel and portable technology. However, further investigations of other restorative materials and other laser powers are required.

A novel star-shaped poly(carboxylic acid) for resin-modified glass-ionomer restoratives

We have developed a novel glass-ionomer cement (GIC) system composed of photo-curable star-shaped poly(acrylic acid-co-itaconic acid)s. These polyacids were synthesized via a chain-transfer radical polymerization using a newly synthesized multi-arm chain-transfer agent. The star-shaped polyacids showed significantly lower viscosities in water as compared to the linear polyacids. Due to the lower viscosities, the molecular weight (MW) of the polyacids can be significantly increased for enhancing the mechanical strengths while keeping the ease of mixing and handling. The effects of MW, GM-tethering ratio, P/L ratio, and aging on the compressive properties of the experimental cements were significant. The light-cured experimental cements showed significantly improved mechanical strengths i.e. 49% in yield strength, 41% in modulus, 25% in CS, 20% in DTS, and 36% in FS, higher than commercial Fuji II LC. After aging in water for 1 month, the compressive strength of the novel light-cured experimental cement reached 343 MPa, which was 34% and 42% higher than Fuji II and Fuji II LC, respectively. This one-month aged experimental cement was also 23% higher than itself after one day aging, indicating that aging in water can significantly enhance salt-bridge formation for this novel star-shaped polyacid-comprised GIC.

Seven-year clinical performance of resin composite versus resin-modified glass ionomer restorations in noncarious cervical lesions.

The purpose of this study was to comparatively assess the seven-year clinical performance of a one-bottle etch-and-rinse adhesive with resin composite (RC) and resin-modified glass ionomer (RMGI) restorations in noncarious cervical lesions. One operator placed 70 restorations (35 restorations in each group) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by two independent examiners, using modified US Public Health Service criteria at baseline and 6, 12, 24, 60, and 84 months. The obtained data were tabulated and statistically analyzed using the Fisher and McNemar tests. A difference was significant if p<0.05. Twenty patients were available for recall after seven years (66.6%), and 25 RC and 26 RMGI restorations out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (κ≥0.85). Alfa and bravo scores were classified as clinically acceptable. The McNemar test detected significant differences within RC restorations between baseline and seven-year evaluations for anatomic form, marginal integrity, and retention (p<0.05). For RMGI restorations, a significant difference was identified for marginal integrity (p<0.05). As to material comparison, the Fisher exact showed a better retention performance for RMGI restorations than for RC restorations (p<0.05). Twelve composite restorations were dislodged (52.0% retention) and three ionomer restorations were lost (88.5% retention). The cumulative success rate for RC and RMGI was 30% and 58.1%, respectively. After seven years of service, the clinical performance of RMGI restorations was superior to that of the adhesive system/resin composite restorations in this study.

Improving Oral Health Status of Children in Tabuk, Saudi Arabia

This comprehensive community health intervention aimed to improve the oral health and reduce the incidence of dental caries in Tabuk schoolchildren. The program supports the public health pyramid that provides a framework to improve health and included creating and evaluating a school oral health surveillance system, applying fluoride varnish and dental sealants on high- and medium-caries risk children, and providing treatment for existing diseases. In a pilot phase, 48 children (26 males 22 females; mean age 6.42; dmft 9.33, Decayed, Missing, or Filled Primary and Permanent Teeth (DMFT) 3.27) received the dental services, both treatment and prevention. Three hundred seventy-eight composite resin or resin-modified light-cured glass ionomer restorations were placed. One-hundred and eighteen teeth received pulp therapy (pulpotomy or pulpectomy), ten of which received stainless steel crowns. A total of 72 teeth were extracted due to caries. To understand the effects of dental disease on children, as perceived by parents, an oral health-related quality of life survey was completed and analyzed. Results found an underestimation of the role the teeth play, particularly primary teeth, in the general health and wellbeing of the child. The program’s main evaluation effort focused on the process and outcome objectives, including the number of children received care, number of teeth received restorations and sealants, and number of children received fluoride varnish, etc. Analyzing the effect of the program on oral hygiene revealed an improvement in oral health, as a direct result of oral health educational sessions and one-to-one counseling. There is an urgent need to expand the program to include all primary schools.

Randomized Controlled Clinical Trial Evaluating Connective Tissue Graft Plus Resin‐Modified Glass Ionomer Restoration for the Treatment of Gingival Recession Associated With Non‐Carious Cervical Lesion: 2‐Year Follow‐Up

The aim of this clinical study is to evaluate the 2-year term results of gingival recession (GR) associated with non-carious cervical lesions (NCCLs) treated by connective tissue graft (CTG) alone or in combination with a resin-modified glass ionomer restoration (CTG+R). Thirty-six patients with Miller Class I buccal GR associated with NCCLs completed the follow-up. The defects were randomly assigned to receive either CTG or CTG+R. Bleeding on probing (BOP), probing depth (PD), relative GR, clinical attachment level (CAL), and cervical lesion height coverage were measured at baseline, 6 months, 1 year, and 2 years after treatment. Both groups showed statistically significant gains in CAL and soft-tissue coverage. The differences between groups were not statistically significant in BOP, PD, relative GR, or CAL after 2 years. Cervical lesion height coverage was 79.31% ± 18.51% for CTG and 71.95% ± 13.25% for CTG+R (P >0.05). Estimated root coverage was 91.56% ± 11.74% for CTG and 93.29% ± 7.97% for CTG+R (P >0.05). Within the limits of the present study, it can be concluded that both procedures provide comparable soft tissue coverage after 2 years of follow-up.

Healing Patterns After Subgingival Placement of a Resin-Modified Glass-Ionomer Restoration: A Histometric Study in Dogs

The aim of this study was to evaluate, clinically and histometrically, the effects of subgingival placement of a resin-modified glass-ionomer restoration during flap surgery. Nine dogs were included in this study. The mandibular canines were randomly assigned to receive either a transgingival resin-modified glass-ionomer restoration (test group) or no restoration (control group). The apical margins of the restorations in the test group and a reference notch on those in the control group were placed at the level of the bone crest. Clinical parameters were recorded 7 days before sacrifice. The dogs were sacrificed after 107 days, and undecalcified sections were obtained for histologic evaluation. Clinically, both groups presented significant clinical attachment loss and an increase in probing depth, but differences between groups were not statistically significant (P > .05). Histologically, a significant difference between groups was observed for length of epithelium (test, 4.05 ± 0.57 mm; control, 3.36 ± 0.63 mm; P = .01). The test group showed more bone resorption (2.02 ± 1.47 mm) when compared with the control group (0.74 ± 0.37 mm) (P = .048). It can be concluded that even with the claimed favorable properties of resin-modified glass ionomer, the presence of the restoration within the biologic width causes increased migration of the apical epithelium and bone resorption.

Tensile bond characteristics between composite resin and resin-modified glass-ionomer restoratives used in the open-sandwich technique

The clinical success of large class II resin-modified glass-ionomer cement/composite resin (RMGIC/CR) 'open-sandwich' restorations in permanent or primary molars may be influenced by certain bonding parameters. To examine in vitro the effect of placing/curing mode on the RMGIC/CR bond strength. Two restoratives, a CR (Z250), a RMGIC (Vitremer) and a bonding agent (Adper Single Bond 2), all of 3M ESPE, were used for preparing five groups of seven specimen sticks each. The bond between the two restorative materials at the stick centre was created in the three test groups by: (A) 1-step placing RMGIC in contact with CR, then photocuring; (B) 2-step RMGIC placing/curing, then CR placement/curing; (C) 3-step RMGIC placing/curing, bonding agent placing/curing, CR placing/curing. Control groups consisted of sticks made of CR alone (D, positive) and RMGIC alone (E, negative). The specimens were subjected to tensile stress measurements in an Instron dynamometer and examined by scanning electron microscope for type of failure. Tensile bond strength, tensile strain and elastic modulus differences were examined with one-way ANOVA and Tukey test. Among experimental groups, Group C exhibited significantly higher tensile strength (MPa) means (A=12.11±4.72, B=15.69±5.18, C=19.08±4.05) and significantly higher tensile strain (%) means (A=0.50±0.11, B=0.64±0.19, C=0.98±0.24), compared to Group A, at p=0.05. Group D had significantly higher tensile strength and strain than all other groups. No statistically significant differences were observed in the elastic modulus. The use of bonding agent (Group C) resulted in absence of adhesive failures as seen by SEM. The use of bonding agent improved the CR/RMGIC bond by tensile strength and strain tests.