No description available.

Objective : To determine if the linear measurements made in Galileos CBCT in the presence of soft tissue using cadaver heads are accurate. Materials and methods : CBCT images were obtained in Galileos CBCT device after placement of gutta percha markers, three to the facial and one to the lingual of the area of interest in the mandible. The CBCT orthoradial image showing perfect alignment of the lingual with a facial marker was selected as the plane of measurement. The distance between the most superior and most inferior point on the bone on the selected plane was measured electronically. The specimens were sectioned along this plane and physical measurements were obtained with digital calipers. Linear distance was measured between the most superior and most inferior point on the bone on the selected plane. This distance was measured in 6 specimens with calipers and compared to the distance measured on the corresponding CBCT images. Results: A paired-sample t-test was used to determine whether the mean difference measurement value of two measurements at right side was significantly equal to zero. The data revealed that overall there was no statistically significant difference between CBCT and Physical measurement on right side (p=0.2298), left side (p=0.3554) and overall between CBCT and Physical measuremnets (p=0.2684). Conclusions: Based on the statistical evaluation of the CBCT and Physical measurements it can be concluded that Galileos CBCT unit is reliable for evaluation of linear measurements between anatomic structures within the bone in the presence of soft tissues in the mandible specially for measuring height of available bone.

Title: The Esthetic Outcome and the Infiltration Capacity of Three Resin Composite Sealers Compared to ICON (DMG, America). Objective: The aim of these studies, including a randomized control in-vitro study and a survey study was to answer the following question: In treating initial caries lesions, is the esthetic outcome and the infiltration capacity of the three resin composite sealers; BisCover LV (Bisco Dental), Optiguard (Kerr), PermaSeal (Ultradent) similar to that of the gold standard ICON (DMG, America) resin infiltrant. Methods: A sample of 75 extracted human permanent molars were painted with an acid resistant nail varnish (Revlon, USA) to protect the tooth surface from demineralization leaving only two panels of 1x7 mm of exposed enamel on the buccal and the lingual surfaces of each tooth to be demineralized. Samples were immersed in an acidic gel (500g of Fisher G-8 Gelatin, 275 Bloom, 0.1% thymol, lactic acid, pH 4.30) for a period of 3 months to create artificial initial caries lesions. Seventy-five specimens were randomly assigned to 5 groups: I: ICON (DMG, America), B: BisCover LV (Bisco Dental), O: Optiguard (Kerr), P: PermaSeal (Ultradent) and C: control group. Specimens were hemi sectioned yielding two halves, each with a panel of 1x7 mm of initial caries lesion. One side was used to assess the esthetic following the caries lesion resin infiltration with ICON, BisCover LV, Optiguard and PermaSeal applied according to ICON manufacturer instructions. The control group (C) did not receive any treatment and was only included in the esthetic part of this study. Preoperative and postoperative photographs were taken. Two sets of photographs were taken for the control group. The preoperative, postoperative and control group photographs were installed in a PowerPoint presentation and placed side by side on a black background. A total of 17 operative faculties and residents at the department of operative dentistry at the University of Iowa (UI) participated in the survey. The esthetic improvement was assessed based on a 100-mm visual analogue scale (VAS). A value between 0 and 20 indicated slight esthetic improvement. A value between 20 and 40 indicated mild esthetic improvement. A value between 40 and 60 indicated moderate esthetic improvement. A value between 60 and 80 indicated high esthetic improvement. A value between 80 and 100 indicated outstanding esthetic improvement. A value of 100 indicated full esthetic recovery. Each subject was asked to look at the preoperative and postoperative photographs of a specimen in each slide and place a line on the respective VAS according to her/his opinion of esthetic improvement. The survey was conducted twice in two different sessions to evaluate the inter-rater and intra-rater reliability. For lesions on the opposite side, the resins: ICON, BisCover™LV, Optiguard and PermaSeal were applied according to the indirect dual fluorescence technique protocol using the red fluorophore rhodamine B isothiocyanate (RITC 0.1%; Sigma Aldrich, Steinheim, Germany) and the green sodium fluorescein (NaFl; Sigma Aldrich). Specimens were sectioned in a mesio-distal direction yielding thin sections of 200 μm and were visualized under the Confocal Laser Scanning Microscope (CLSM, Leica Microsystems, Buffalo Grove, IL.) to assess the infiltration depth percentage (ID%) and the infiltration area percentage (IA%) following the application of the different resins. Statistical analysis: The effect of treatment type on ID% and IA% was evaluated using the one-way ANOVA. The effect of treatment type on esthetic improvement measures represented by VAS scores was evaluated using the non-parametric analogue of the one-way ANOVA; Kruskal-Wallis test. All pairwise comparisons were performed using the Tukey method with an overall 0.05 level of significance. Spearman rank correlations were used to assess the relationship between esthetic improvement measures and infiltration measures. Validity of assumptions related to normality and variance homogeneity were assessed using the Shapiro-Wilk and Brown-Forsythe tests, respectively. The intra-class correlation and associated 95% confidence interval reflecting the reproducibility of the mean VAS scores and the reliability among the evaluators were obtained using the method of Shrout and Fleiss. The Wilcoxon Signed Rank procedure was used to evaluate differences between sessions for individual evaluators. The paired student’s t-test was used to detect any systematic differences between the mean VAS scores at session 1 and 2. Bonferroni adjustment for multiple testing was made for the 17 tests associated with individual raters, using an overall 0.05 level of significance. Results: the mean IA% values were significantly higher in the ICON group compared to the other three treatment groups. Optibond and Permaseal groups resulted in intermediate values that did not differ significantly from each other. Biscover group yielded the lowest mean values and were significantly lower than that of the other three treatment groups. The results of the ID% values were consistent with the results of the IA% values. the mean ID% values were significantly higher in the ICON group compared to the other three treatment groups. Optibond and Permaseal groups resulted in intermediate values that did not differ significantly from each other. Biscover group yielded the lowest mean values and were significantly lower than that of the other three treatment groups. The distribution of esthetic improvement outcomes represented by the average VAS scores for session 1 (AVGVAS1), average VAS scores for session 2 (AVGVAS2), and the combined average VAS scores (AVERAGED_VAS) for each sample obtained from the two sessions were all significantly lower in the control group than in the other four treatment groups. Biscover yielded intermediate average VAS values. ICON, Optiguard and Permaseal yielded significantly greater average VAS values than both the control and Biscover groups and were not significantly different from each other. According to the Spearman rank correlations which was used to assess the relationships between the esthetic improvement measures; AVGVAS1, AVGVAS2 and AVERAGED_VAS for each sample and the two measures of infiltration; the IA% and the ID%, all results were highly significant (p<0.0001) and indicative of a moderately large positive correlation between each of the infiltration measures and the three esthetic improvement measures. The Spearman coefficients for the six relationships evaluated were quite similar, ranging from about 0.523 to 0.548. Conclusion: The resin composite sealers BisCover LV, Optiguard and Permaseal can infiltrate artificial initial caries lesions. The esthetic outcome of artificial initial caries lesion following resin infiltration with Optiguard and Permaseal was similar to ICON and thus might be adequately used in caries resin infiltration. BisCover LV showed the least esthetic improvement and thus might not be indicated for the esthetic management of initial caries lesions but might be used for caries prevention purposes. The esthetic improvement is correlated to the resin infiltration depth to a certain extent after which the esthetic outcome will not be visually impacted.

Objectives: This study evaluated the effects of extended acid etching on microtensile bond strength (µTBS) of a etch and rinse adhesive system to sound vital dentin. Etching times of 5, 20 and 80 seconds was used to evaluate the µTBS on vital dentin with resin bonded composite [RBC] restoration (Esthet-XTM) which used a two step etch and rinse adhesive system(Prime Bond NTTM) for bonding. Methods: 26 premolars which were going to be extracted for orthodontic treatment were used for this experiment. The teeth were randomly divided into 3 groups based on the etch times and restored with RBC using two step adhesive and extracted in `Guarulhos University' Brazil. After extraction, these teeth were sectioned ( Microtome) in such a way to obtain 2 testing beams of 2mm diameter from each tooth were obtained which were trimmed (CNC specimen former, University of Iowa, IA, USA) to a dumb bell shape and tested for the microtensile bond strength in University of Iowa. Out of 26 teeth, 46 beams were obtained. For statistical analysis, One-way ANOVA with post-hoc Tukey-Kramer's test was used to determine whether there were significant differences in micro-tensile bond strength among three etching times under each condition. All tests had a 0.05 level of statistical significance. SAS for Windows (v9.1, SAS Institute Inc, Cary, NC, USA) was used for the data analysis. Fracture mode was analyzed using scanning electron microscopy. Results: Bond strengths in 20 seconds and 5 seconds groups were significantly greater than that observed in 80 seconds group, while there was no significant difference between 20 and 5 etching times.SEM showed majority of the failure was adhesive/ joint failure. Significance: The results in this In-vivo study are consistent with other in-vitro studies and thus bring an insight on the importance of duration of phosphoric acid application on dentin and extended etch times could compromise the bond strength of the restorations.

No description available.

Objective: To assess the effects of ceramic opacity and thickness on delivered radiant exposure and degree of conversion and microhardness of the light-cured resin cement. Materials and Methods: IPS e-Max ceramic discs (Ivoclar Vivadent) were fabricated in 3 thicknesses (0.5, 1.0, and 1.5mm) and 4 opacities (HT, LT, MO, HO) (n=3/per group). Light-cured resin cement (Variolink Veneer Luting Cement - shade MVO, Ivoclar Vivadent) 50µm thick was cured through these ceramics disks using a quartz tungsten halogen curing light unit (Optilux 501, Kerr) with its radiant exposure measured by MARC from a fixed distance (1.5mm). Knoop microhardness was used to evaluate the bottom degree of cure and was correlated with the radiant exposure deliverd. Descriptive statistics were conducted. One- and two-way ANOVA with post-hoc Tukey's HSD test, Pearson correlation test, the simple linear regression analysis were used for the statistical analyses (alpha=0.05). Results: Significant interaction was found between ceramic thickness and opacity on radiant exposure (p=0.0078). Subsequent analyses demonstrated that there was a significant simple effect for opacity and for thickness on radiant exposure under different conditions of thickness and opacity. A significant relationship was found between resin cement microhardness and radiant exposure (p=0.0001) below 4.5 J/cm2. Moreover, the Pearson correlation coefficient of 0.93 indicated a strong correlation between the two variables below 4.5 J/cm2 of radiant exposure delivered. Conclusion: Ceramic opacity and thickness affect the polymerization of light-cured resin cements and need to be considered and compensated for when bonding indirect restorations. Based upon the findings of this preliminary study, the final study is ongoing.

No description available.

Objectives: This study used three lasers (red, green and blue) with a spectrophotometer to compare the light propagation [Absorption (A), Transmittance (T), Attenuation (K) and Scattering Anisotropy Coefficient (g)] in dental tissues and nano filled resin based composite using three incremental build-up techniques: one shade (Body), two shades (Enamel and Dentin), and three shades (Enamel, Transparent and Dentin). Methods: Twenty un-erupted recently extracted human 3rd molars (shade: B1) were used to obtain 40 tooth slabs (1.5 mm thickness x 4 mm length). The samples were randomized and equally distributed into four experimental groups: Positive Control (Dental Tissues – enamel, dentino- enamel-junction and dentin), Technique 1 (T1 = 1 shade, B1B), Technique 2 (T2 = 2 shades, A2Dentin/B1Enamel), and Technique 3 (T3 = 3 shades, A2Dentin/Transparent/B1Enamel). One calibrated operator performed all procedures and tests. Cavity preparation was standardized using a #58 carbide bur. Using the spectrophotometer, each specimen was irradiated by the three LASERs. A Voltmeter recorded the light output signal and from this raw data the following optical constants were calculated: absorption (A), transmittance (T), attenuation coefficient (K) and Scattering Anisotropy Coefficient (g). The data were analyzed using One-way ANOVA, followed by the post-hoc Tukey's test. All tests utilized a significance level of 0.05. Results: Regarding absorption and transmittance, dental tissues were significantly different compared to the three build-up techniques for all lasers. Regarding the attenuation coefficient, dental tissues were not significantly different for T2 and T3 for the blue and red lasers, however they were significantly different for the green laser. There was no significant difference among the three lasers for T2 and T3. Conclusion: Within the limitations of this study, none of the build-up techniques used was able to reproduce the dental tissues optical properties and Technique 2 (2 shades) and Technique 3 (3 shades) resulted in a similar pattern of light propagation.

No description available.

Ethanol‐wet bonding (EW) has been proved to effectively infiltrate hydrophobic monomers into the demineralized hydrophilic dentin matrix and create a more degradation‐resistant network when bonding to normal dentin. Caries-affected dentin (CAD) has consistently demonstrated lower bond strength than normal dentin. Objective: To evaluate effect of EW on resin-CAD bond strength. Methods: Seventy five human molars with occlusal caries were randomly divided into water-wet (WW) and EW groups. CAD was obtained using the combined criteria of visual examination, surface hardness to an excavator and carbide bur and staining with 1% acid red in propylene glycol dye solution (Caries detector, Kuraray). For EW, the etched and water rinsed dentin was subsequently rinsed with absolute ethanol for 15s x3 before primer application. Four bonding agents, Bis-GMA/TEGDMA (ER2), Bis-GMA/HEMA (ER3), Bis-GMA/2-MP/HEMA (ER5), and Adper Scotchbond Multi Purpose (SBMP) were applied followed by resin-based composite (Heliomolar, Ivoclar Vivadent) incrementally built-up. Specimens (549) with a square cross-sectional area of approximately 0.7 mm2 were formed. Specimens (one day: 263; 6 month: 276) were subjected to micro-tensile bond test. Data were analyzed by one two-way and three-way ANOVA, two-sample t-test, and the parametric Weibull regression models. Result: There was a significant difference in the mean microtensile bond strength between WW and EW substrate condition for ER2 (p=0.0443). The mean microtensile bond strength with EW was significantly greater. Conclusion: Unlike prior research using normal dentin, EW bonding had significant effect only on 6 month bond strength to CAD for ER2.