Comparison of Resin Infiltration Technique with Conventional Preventive Applications on Occlusal Fissures in Terms of Chemical Analysis and SEM.

OBJECTIVE: To compare the subsurface mineral loss preventing capability of resin infiltration technique with topical fluoride and fissure sealant applications to demineralized occlusal fissures under simulated oral conditions. MATERIALS AND METHODS: Occlusal surfaces of 64 extracted intact human third molars were demineralized. Next, the teeth were classified into four groups according to preventive applications (n = 16): G1, Specimens used as the control group with no preventive treatment; G2, Topical fluoride application (APF Gel/ DEEPAK); G3, Fissure sealant application (ClinproTMSealant/ 3M ESPE); and G4, Resin infiltration technique (Icon/ DMG). Chemical compositions before pH cycling were evaluated for eight specimens from each group. The remaining eight teeth from each group were subjected to pH cycling for 15 days to simulate the oral conditions. Subsequently, the specimens were fractured after immersion in liquid nitrogen and the subsurface fluoride (F), calcium (Ca), phosphorus (P) levels, and Ca/P ratio of each specimen were measured using energy dispersive x-ray spectrometer (EDS). The data were subjected to statistical analysis (p = 0.05). The effects of preventive applications to surface topography of specimens were evaluated using scanning electron microscope (SEM). RESULTS: There were no significant differences among the groups in subsurface F, Ca, and P levels and Ca/P ratios before or after pH cycling (p > 0.05). All three preventive applications were effective during pH cycling according to SEM observations. CONCLUSIONS: The subsurface mineral loss preventing capability of resin infiltration technique applied to occlusal fissures was comparable to topical fluoride and fissure sealant applications. CLINICAL SIGNIFICANCE: The resin infiltration technique could represent a valid alternative to traditionally used both preventive and restorative treatments for treating initial carious lesions on occlusal fissures, offering the advantages of better resin penetration and retention.

Effect of chewing gums with xylitol, sorbitol and xylitol-sorbitol on the remineralization and hardness of initial enamel lesions in situ.

BACKGROUND: The purpose of this study was to determine the effect of three chewing gums and paraffin on the remineralization and the hardness of demineralized enamel. MATERIALS AND METHODS: A total of 12 subjects wore intraoral palatal appliances with two demineralized bovine enamel slabs. The study consisted of four experimental periods each lasting 21-days, during which subjects were assigned to one of three gum-chewing regimens: gum containing sorbitol, xylitol and a mixture of sorbitol and xylitol and with paraffin as control. The appliances were worn during gum-chewing for 20 min and then retained for 20 min 4 times/day. The slabs were subjected to energy dispersive X-ray spectroscopy analysis and surface microhardness measurements before in setting into the appliance and after the experimental period. The data were subjected to analysis of variance for repeated measures. A P < 0.05 was considered statistically significant. RESULTS: Mineral analysis revealed no significant difference between the baseline and after chewing periods for all groups (P > 0.05). No significant difference was found among the groups either for the baseline measurements or after chewing periods (P > 0.05). All groups showed higher microhardness values after the chewing periods than the baseline except for the Vivident Xylit group (P < 0.05). CONCLUSION: The chewing of gum had no effect on the Ca/P ratio of demineralized enamel surfaces. The hardening of the demineralized enamel surfaces may vary according to the type of chewing gum.

Effects of delayed finishing/polishing on surface roughness, hardness and gloss of tooth-coloured restorative materials.

OBJECTIVES: The aim of this study was to investigate the effect of delayed finishing/polishing on the surface roughness, hardness and gloss of tooth-coloured restorative materials. METHODS: Four different tooth-coloured restoratives: a flowable resin composite- Tetric Flow, a hybrid resin composite- Venus, a nanohybrid resin composite- Grandio, and a polyacid modified resin composite- Dyract Extra were used. 30 specimens were made for each material and randomly assigned into three groups. The first group was finished/polished immediately and the second group was finished/polished after 24 hours. The remaining 10 specimens served as control. The surface roughness of each sample was recorded using a laser profilometer. Gloss measurements were performed using a small-area glossmeter. Vickers microhardness measurements were performed from three locations on each specimen surface under 100g load and 10s dwell time. Data for surface roughness and hardness were analyzed by Kruskal Wallis test and data for gloss were subjected to one-way ANOVA and Tukey test (P <.05). RESULTS: The smoothest surfaces were obtained under Mylar strip for all materials. While there were no significant differences in surface roughness of immediate and delayed finished/polished Dyract Extra samples, immediately finished/polished Venus and Grandio samples showed significantly higher roughness than the delayed polished samples (P <.05). In Tetric Flow samples, immediately finishing/polishing provided smoother surface than delayed finishing/polishing (P <.05). The highest gloss values were recorded under Mylar strip for all materials. While delayed finishing/polishing resulted in a significantly higher gloss compared to immediate finishing/polishing in Venus samples (P <.05), no differences were observed between delayed or immediate finishing/polishing for the other materials (P>.05). The lowest hardness values were found under Mylar strip. Delayed finishing/polishing significantly increased the hardness of all materials. CONCLUSIONS: The effect of delayed finishing/polishing on surface roughness, gloss and hardness appears to be material dependent.

Frailty among HIV-infected persons in an urban outpatient care setting.

OBJECTIVES: Frailty among HIV-infected persons is increasingly recognized but data are limited. We aimed to determine frailty prevalence, predictors and clinical significance in this population. METHODS: This was a prospective cross-sectional study of HIV-infected persons > or =18 years attending Washington University HIV Clinics between June and December 2008. Frailty was defined by > or =3 of 5 criteria: weight loss, low physical activity, exhaustion, weak grip strength and slow walking time. Independent predictors of frailty were evaluated using multivariate logistic regression analyses. RESULTS: 445 persons were studied; mean age 41.7 years, 71% male, 63% African American with a mean 8.4 years since HIV diagnosis. 75% were on antiretroviral therapy with median CD4+437 cells/mm(3). Frailty prevalence was 9%. Independent predictors of frailty included unemployment, greater number of comorbid conditions and past opportunistic illnesses, higher depression severity score, receipt of antidepressants and lower serum albumin. Hospitalization rates were greater for frail persons with a five-fold longer duration of inpatient stay. CONCLUSION: HIV infection was associated with a premature presentation of frailty. Frailty was associated with greater comorbidity, markers of advanced immunodeficiency and adverse socioeconomic and clinical outcomes. Further study of frailty in patients with HIV infection is warranted.

The effect of saliva contamination on microleakage of an etch-and-rinse and a self-etching adhesive.

PURPOSE: To evaluate the effect of saliva contamination on the microleakage of an etch-and-rinse adhesive and a self-etching adhesive. MATERIALS AND METHODS: Class V cavity preparations at the cementoenamel junction were made on the buccal and lingual surfaces of 40 freshly extracted human molars. The teeth were randomly assigned into two groups for different adhesives: Group I, Single Bond (two-step etch-and-rinse adhesive) and Group II, Futura Bond NR (one-step self-etching adhesive). The adhesive materials were applied according to their manufacturers' recommendations. The specimens were then further subdivided into five subgroups (A-E; n = 8): group A, contamination before adhesive curing; group B, contamination before adhesive curing and re-application of adhesive; group C, contamination after adhesive curing; group D, contamination after adhesive curing and re-application of adhesive; and group E, no contamination (control). Contamination of adhesive surfaces was performed with fresh natural saliva and the saliva was removed by a gentle air blast. The specimens were restored with Z250 hybrid composite. After thermocycling (500x, 5 degrees C to 55 degrees C) and immersion in 0.5% basic fuchsin, the dye penetration was evaluated under a stereomicroscope. Statistical analysis was performed with the Kruskal-Wallis test at p < 0.05. RESULTS: No statistically significant differences were found among the contamination subgroups on the enamel or on the dentin for either group (p > 0.05). There was no significant difference in leakage between Group I and Group II for any subgroup (p > 0.05). CONCLUSION: Contamination of adhesives with saliva before and after adhesive curing did not worsen the microleakage of the two-step etch-and-rinse adhesive Single Bond or the one-step self-etching adhesive Futura Bond NR.

Radiopacity of direct esthetic restorative materials.

This study determined the radiopacity of 21 commercially available direct esthetic restorative materials with reference to an aluminum step wedge and an equivalent thickness of enamel and dentin. A total of 168 samples measuring 6 mm in diameter and 1 mm in thickness, with eight samples of each material, were prepared from restorative materials. Enamel and dentin samples 1-mm thick were also prepared by longitudinally sectioning eight extracted human permanent molars using a microslicing machine. The optical densities of each restorative material, along with one tooth section and an aluminum step wedge were measured from radiographic images using a transmission photodensitometer. The optical density values of the specimens were used to determine the aluminum thickness equivalent values. The data were analyzed with one-way analysis of variance (ANOVA) and Duncan's multiple range tests. The results showed statistically significant differences among materials. Tetric Ceram had the greatest radiopacity value and was higher than enamel. All materials except for the microfilled resin composite Filtek A 110 had radiopacity values greater than dentin and possessed sufficient radiopacity to meet ISO 4049 standard. Significant differences were found among materials of the same composition when compared to enamel.

Artificial formed caries-like lesions around esthetic restorative materials.

Dental restorations fail for a variety of reasons. Secondary caries is one of the primary causes of failure of dental restorations. One method for reducing frequency and severity of this problem is the use of fluoride containing restorative materials. The ability of a material to inhibit secondary caries formation is an important clinical therapeutic property. This investigation assessed the capacity of esthetic restorative materials to resist caries in vitro. Class V cavities were prepared in buccal and lingual surfaces of 50 extracted sound third molars. The occlusal and gingival cavosurface margin of each preparation was on enamel surface. The five materials were used: Conventional glass ionomer cement Ceramfil beta (PSP), two polyacid modified resin composites Compoglass (Vivadent) and Dyract (Dentsply/DeTrey), non fluoride releasing composite resin Valux Plus (3M) and fluoride releasing composite resin Tetric (Vivadent). After 10 weeks in an acid gel for caries-like lesion formation, the teeth were sectioned occluso-gingivally through the middle of the restorations and examined by polarized light microscopy, while immersed in water. The statistical analysis of the results showed that secondary caries initiation and progression might be reduced significantly when fluoride-containing materials were placed. The conventional glass ionomer cement (Ceramfil beta) provided the highest protection against caries attack and the non-fluoride releasing composite resin (Valux Plus) restoration provided the least (p<0.05).