Fluoride Release from Two High-Viscosity Glass Ionomers after Exposure to Fluoride Slurry and Varnish

The effect of brushing with different fluoride slurries on the fluoride release (FR) of different high-viscosity glass ionomer cements (GICs) was investigated. Fifty-eight discs were fabricated from two high-viscosity GICs (GC Fuji IX (F9) and 3M ESPE Ketac-fil (KF)). Five specimens from each brand were used to measure Vickers microhardness and the remaining were randomly assigned to one of four groups (n = 6) based on two-factor combinations: (1) fluoride concentration in the abrasive slurry (275 or 1250 ppm fluoride as NaF) and (2) immersion in a 22,500 ppm fluoride-containing solution. Specimens were brushed for a total of 20,000 strokes over 4 days with daily FR measurement. Data were analyzed using analysis of variance and Bonferroni tests (α = 0.05). Baseline FR and microhardness values were different between the two tested material brands. Exposure to a 22,500 ppm solution was associated with higher FR but not the exposure to 1250 ppm slurries. Brushing and immersion of glass ionomer cements in a 22,500 ppm F solution led to higher FR that was more sustained for KF. Type of the glass ionomer, progressive brushing, and fluoride varnish affected FR but not the fluoride content in the abrasive slurry

OPTIMIZING LIGHT-CURED COMPOSITE PROPERTIES WITH CAMPHROQUINONE AND BUTYLHYDROXYTOLUENE COMBINATIONS

poster abstractPolymerization shrinkage is an inherent property in dental composite that has major effects on its clinical performance. Many strategies on minimizing the shrinkage have been explored in the past. Here we propose that, by op-timizing the dose combinations of photoinitiator and polymerization inhibitor, we can effectively reduce the polymerization shrinkage stress without sacri-ficing the mechanical properties of dental composite. The objective of this study therefore was to investigate the effects of a common photoinitiator, camphroquinone (CQ), and inhibitor, butylhydroxytoluene (BHT), at clinical-ly-relevant concentration combinations on the shrinkage properties and me-chanical properties of light-cured composite. Samples were prepared by mix-ing bisphenol-A-glycidyl methacrylate, urethane dimethacrylate, and tetraethyleneglycol dimethacrylate at a 1:1:1 ratio. Borosilicate glass fillers constituted 70% of the resin weight. Sixteen groups of resin composite were prepared from the combination of four CQ (0.1%, 0.5%, 1.0%, and 1.5%) and four BHT (0.0%, 0.5%, 1.0%, and 1.5%) levels. Six properties were tested, including Flexural strength (FS) flexural modulus (FM), degree of conversion (DC), contraction stress (CS), stress rate (SR), and gel point (GP). The effects of CQ and BHT combinations on each of these properties were evaluated using two-way analysis of variance (ANOVA). Groups with low CQ and BHT showed moderate values for FS, FM, SR and CS with DC around 70%. Increasing the BHT concentration caused a decrease in SR, CS, DC and an increase in GP values. Increasing the CQ content gave a steady increase in values for FS and FM. Notable, in CQ=1.5% group, increasing BHT from 0 to 1.5% result in a statistically significant decrease in polymeri-zation shrinkage stress (p<0.05) while maintain the same mechanical prop-erties. In this project, we successfully demonstrated that the polymerization shrinkage of resin composite can be tailored through CQ and BHT combina-tions with high CQ and high BHT showing the most promising results

Effect of Gap Geometry on Secondary Caries in Vitro

Indiana University-Purdue University Indianapolis (IUPUI)Objective: To investigate the effect of the size of the space between the restoration and the dentinal wall of the tooth (i.e. the dentinal portion of the gap) on the development of secondary caries. Methods: Tooth-resin-matrix composite specimens were mounted on custom-made gap-model stages. Specimens were divided into four groups (n=10). Group 1 had a uniform gap size of 30μm throughout both enamel and dentin. Group 2 had a 30μm enamel gap size with a 530μm dentinal gap. Group 3 had 525μm gaps in both enamel and dentin. Group 4 had 525μm and 1025μm gaps in enamel and dentin, respectively. Specimens were attached to plastic Petri plates, gas-sterilized and then incubated in a microbial caries model with S. mutans TH16 in (1% sucrose tryptic soy broth for 1 h, 4 times/day, and with a buffer solution for the rest of the day). After 8 days of incubation, tooth specimens were sectioned and stained with a rhodamine B solution. Digital images were taken under a confocal microscope and analyzed for lesion size at the enamel outer lesion (EOL), enamel wall lesion (EWL), dentin wall lesion next to the DEJ (DWL-A) and dentin wall lesion at 750µm from the DEJ (DWL-B). Results: No difference in EOL size was found between the groups. DWL-A and -B were larger in group 3 than groups 1and 2. Larger DWL-B was found in group 3 than group 4. Group 4 had marginally significant larger EWL than groups 1 and 2 (p=0.0652 and p=0.0648, respectively). Also, group 4 had marginally significant (p=0.0607) larger DWL-B than group 1. Conclusions: Based on the results of this study, it can be concluded that the presence of additional space at the dentinal wall area did not affect secondary caries development as long as the enamel gap was small. However, with enamel gaps of ≈500 µm, the presence of the additional gap space at the dentinal wall led to the development of smaller dentinal wall lesions at the deeper parts of the simulated cavity. Also, in uniform gaps, the size of the interface was positively correlated with size of the dentinal wall lesions

Effect of fluoride and abrasives on artificial enamel caries lesions

Indiana University-Purdue University Indianapolis (IUPUI)Hypothesis: The interaction between the abrasive level and fluoride concentration of dentifrice slurries modulates the surface loss (SL) and remineralization of incipient enamel caries (IEC). Methods: Three types of IEC were created and six experimental slurries with different combinations of fluoride content and abrasive level were tested. In experiment 1, the three IEC were subjected to brushing (with experimental slurries) and remineralization cycles for 5 days. Fluoride concentrations (0 and 275 ppm as NaF) and abrasive levels (Low and High) were tested. SL was determined by optical profilometry at baseline and after 1, 3, and 5 days. In experiment 2, changes in IEC mineral content (Δ(ΔZ)C) and depth (ΔLC) were investigated at baseline and after the 5-day cycling with transverse microradiography. In experiments 3 and 4, SL of MeC and CMC lesions were further studied, respectively; testing not only fluoride concentration (275 and 1250 ppm as NaF) and abrasivity (low and high) of the slurry, but also the brushing frequency (1x, 2x, and 3x/day). Brushing-remineralization cycles were performed for 7 days. Statistical analyses were performed at 5% significance level. Results: Experiment 1: overall, brushing with the high-abrasive slurry caused more SL than with the low-abrasive. For CMC and MeC lesions, 0 ppm F had more SL than 275 ppm F only after day 3. Fluoride had no effect on the SL of HEC lesions. Experiment 2: fluoride and abrasives did not have a significant effect on IEC. HEC had significantly lower Δ(ΔZ)C than CMC and MeC, with CMC and MeC not differing from each other. Lesion type had no effect on ΔLC. Experiment 3: brushing CMC lesions 3x/day with 1250 ppm F increased SL compared to 1x/day, after 5 and 7 days. Study 4: brushing MeC lesions with high abrasive slurry containing 1250 ppm F increased SL after 5 and 7 days. Conclusions: The IEC tested showed different SL and remineralization behaviors. The fluoride content and abrasive level of the toothpaste showed to be relevant modulating the SL of enamel caries lesions as well as their remineralization behavior

Artificial Caries Lesion Characteristics after Secondary Demineralization with Theobromine-Containing Protocol

Developing artificial caries lesions with varying characteristics is needed to adequately study caries process in vitro. The objective of this study was to investigate artificial caries lesion characteristics after secondary demineralization protocol containing theobromine and fluoride. Sixty bovine enamel slabs (4 × 3 mm) were demineralized using a Carbopol-containing protocol for 6 days. A baseline area (2 × 3 mm) was protected with acid-resistant nail varnish, after which specimens were exposed for 24 h to a secondary demineralization protocol containing acetic acid plus one of four fluoride/theobromine combinations (n = 15): theobromine (50 or 200 ppm) and fluoride (0 or 1 ppm). Specimens were sectioned and analyzed using transverse microradiography for changes in mineral content, lesion depth, and surface layer mineralization. Data was analyzed using paired t-test and analysis of variance followed by Bonferroni test at 0.05 significance level. After secondary demineralization, fluoride-containing groups had significantly deeper lesions (p = 0.002 and 0.014) compared to the group with 0 ppm fluoride and 50 ppm theobromine. Mineral content and lesion depth were significantly different compared to baseline for all groups. Theobromine did not show an added effect on mineral uptake. Theobromine-containing groups exhibited particularly deep lesions with a more uniform mineral profile in the presence of fluoride

The anticariogenic effect of xylitol on seven Streptococcus mutans strains

Introduction: Xylitol can affect caries-inducing bacteria; however, different Streptococcus mutans strains might respond differently. Aim: To investigate the effect of xylitol on biofilm formation and metabolic activity of seven S. mutans strains. Methods: Seven S. mutans strains (UA159, A32-2, NG8, 10449, UA130, LM7, and OMZ175) were inoculated into 96-well microtiter plates and were tested with various xylitol concentrations (0.0, 0.0016, 0.0031, 0.0063, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 g/mL) for inhibition of biofilm formation and bacterial metabolic activity by recording absorbance values. Lactate dehydrogenase and extracellular polysaccharide assays were conducted at 0.0, 0.1, 0.2, 0.4, and 0.8 g xylitol/mL. Data were analyzed by one-way analysis of variance, Tukey’s, paired t, and LSD tests at 0.05 significance level. Results: Xylitol produced a significant decrease in bacterial biofilm formation compared to controls at 0.4 g/mL, with almost complete lack of biofilm formation at 0.8 g/mL. This was consistent with metabolic activity which demonstrated a significant activity reduction occurring for all strains at 0.4 g/mL, and a complete lack of activity at 0.8 g/mL for all seven strains. There was a trend for lower LDH and EPS production with the increase in xylitol concentration especially with UA159, UA130, and NG8. Conclusion: Xylitol has a clear anticariogenic effect on S. mutans which was slightly different depending on the tested strain confirming that the benefit of xylitol might vary from one patient to another. The effect is more apparent at concentrations of 0.4 g/mL and higher

Ultrasound evaluation of fetal bone development in the collared (Pecari tajacu) and white-lipped peccary (Tayassu pecari)

El estudio del desarrollo fetal permite evaluar las diferentes estrategias adoptadas por las especies de mamíferos para maximizar la supervivencia neonatal. La locomoción autónoma es fundamental para que los recién nacidos realicen actividades de búsqueda de alimento y aumenta la supervivencia neonatal frente a la depredación. En este estudio, evaluamos el desarrollo óseo gestacional de 53 pecaríes de collar (CP, Pecari tajacu) y 61 pecaríes de labios blancos (WLP, Tayassu pecari), recolectados mediante la colaboración de cazadores de subsistencia en la Amazonia. La mineralización ósea y la biometría del esqueleto axial y apendicular se evaluaron mediante exámenes ecográficos, y se calculó el momento de los principales acontecimientos del desarrollo óseo en relación con la longitud dorsal total (TDL) y el porcentaje del período gestacional total (GP). Los primeros signos ecográficos de mineralización del esqueleto axial en CP y WLP se observaron en fetos de 3,4 cm (42 días de gestación, 30% GPCP) y 5,1 cm (51 días de gestación, 32% GPWLP). El desarrollo temprano del esqueleto apendicular se observó por la aparición sincrónica de la escápula mineralizada, el húmero, el radio, el cúbito, el ilion, el isquion, el fémur, la tibia y el peroné con un 36% de GPCP (50 días de gestación) y un 35% de GPWLP (56 días de gestación). El pubis estaba mineralizado en los fetos con un 55% de GPCP (75 días de gestación) y un 59% de GPWLP (94 días de gestación). La mineralización se observó en todos los huesos autópodos al 79% GPCP (109 días de gestación) y al 67% GPWLP (106 días de gestación). Todos los centros primarios de osificación de los huesos largos de las extremidades torácicas y pélvicas estaban mineralizados en los fetos avanzados (GPCP y GPWLP ≥75%). La rótula mineralizada no se observó en fetos avanzados de ninguna de las dos especies. Los centros de osificación secundaria aparecieron por primera vez en la epífisis distal del fémur en el CP (99 días de gestación, 72% GPCP) y en la epífisis distal del radio, fémur y tibia en el WLP (106 días de gestación, 67% GPWLP). Los fetos avanzados de CP y WLP presentaban el 60% (15/25) y el 68% (17/25) del total de centros de osificación secundaria observados presentes en el cerdo doméstico adulto, mientras que los recién nacidos del cerdo doméstico presentaban el 52% (13/25). El temprano desarrollo intrauterino del sistema esquelético en ambas especies de pecaríes sugiere una estrategia de desarrollo precoz, que probablemente se correlaciona con la capacidad neonatal para escapar de los depredadores y reduce la dependencia de los cuidados parentales.Revisión por pares

Spectrum of Pituitary disorders: A retrospective study from Basrah, Iraq [version 2; referees: 2 approved]

Background: Pituitary disorders spectrum includes a wide variety of diseases.This study aimed at a comprehensive description of such disorders for patients from  Faiha Specialized Diabetes, Endocrine and Metabolism Center (FDEMC) in Basrah (Southern Iraq). Methods: Retrospective data analysis of FDEMC for the period from January 2012 through June 2017. We included all patients with pituitary disorders who have MRI pituitary. Results: The pituitary disorders were more common among women. Those with macroadenoma were older than those with microadenoma with nearly equal gender prevalence of macroadenoma. Pituitary adenoma constituted the bulk of pituitary disorders in this registry (67.2%). Growth hormone secreting adenoma were the commonest adenoma seen in 41.0% followed by clinically non-functioning pituitary adenoma(NFPA)in 31.4% and prolactinoma in 26.9%. About 64.8% of pituitary adenoma was macroadenoma. Macroadenoma was seen in 73.4 % of growth hormone secreting adenoma, 61.2% in NFPA and 62.0% of prolactinoma (of them six were giant prolactinoma) Conclusion: Pituitary adenoma constituted the bulk of pituitary disorders in Basrah, growth hormone secreting adenoma is the commonest adenoma followed by NFPA and prolactinoma due to referral bias. A change  in  practice of pituitary adenoma treatment is needed

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p&lt;0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p&lt;0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised