Microleakage and penetration depth of different fissure sealant materials after cyclic thermo-mechanic and brushing simulation.

The aim of the study was to evaluate microleakage and the penetration-depths of different fissure-sealant materials applied with/without enameloplasty after cyclic aging. One-hundred-sixty mandibular molars were divided into non-invasive and enameloplasty preparation groups and eight material subgroups, including: flowable composites (microhyrid, nanohybrid, and nanofilled), three resin-based (unfilled, filled, and highly-filled), a giomer-based, and a glass-ionomer-based fissure sealant. Specimens were subjected to two-year cyclic chewing and brushing simulation. After 5% basic-fuchsin dye penetration, specimens were sectioned and scored under stereomicroscope. Kruskal-Wallis statistical data showed that preparation type significantly affected the penetration of all tested materials (p<0.05), but not significantly affected microleakage (p>0.05). Flowable composites showed the best and the glass-ionomer-based sealant showed the worst penetration and microleakage. Slight preparation of fissures is not important in microleakage. However, enameloplasty significantly enhanced the depth of penetration of the sealants. Flowable composites offer promising results at the fissure sealing.

Intrapulpal temperature changes during curing of different bulk-fill restorative materials.

The aim of this study was to evaluate the intrapulpal temperature changes during the curing of different bulk-fill restorative materials. Ten mandibular molar teeth were selected and occlusal surfaces were removed to obtain a standard 0.5 mm occlusal dentin thickness. Five bulk-fill restorative materials and a conventional resin composite (control) were applied. The intrapulpal temperature changes during the curing of these materials were determined by a device simulating pulpal blood microcirculation. The difference between the initial and maximum temperature values (Δt), was recorded. The data were statistically analyzed with one-way ANOVA and Tukey's HSD test (p<0.05). There were statistically significant differences between materials (p<0.001). The light-curing bulkfill restoratives exhibited the highest Δt values. Equia Forte showed the lowest Δt values among all the groups (p<0.05). Bulk-fill restorative materials causes significantly different temperature changes in the pulp chamber according to curing type. Therefore, clinicians should be considered when using these materials.

Effect of novel restorative materials and retention slots on fracture resistance of endodontically-treated teeth.

OBJECTIVES: The aim of this study was to evaluate the fracture resistance of endodontically-treated teeth restored with nano-hybrid composite resin, bulk-fill flowable and short fibre-reinforced-composite in the absence/presence of retention slots. MATERIALS AND METHODS: One hundred and ten extracted non-carious human mandibular molars received endodontic treatment followed by mesio-occlusodistal (MOD) cavities with 3 ± 0.2 mm thicknesses of buccal and lingual walls. Teeth were divided into two main groups according to the retention slot preparation. The dove-tail retention slots were prepared on the middle of opposite buccal and lingual walls to create mechanical interlocking. Each group was further divided into four sub-groups according to restorative material types: control (no restoration), nano-hybrid composite resin (Filtek™ Z550), bulk-fill flowable (Filtek™ Bulk Fill) and short fibre-reinforced-composite (everX Posterior™). Restored teeth were subjected to compressive load at a strain rate of 1 mm/min. The data were statistically analysed using two-way ANOVA and Tukey's test for multiple comparisons. RESULTS: The fracture resistance was significantly affected by the presence of the retentive slots and restorative material (p < 0.05). Restored teeth with retentive slots significantly increased the fracture resistance compared with restored teeth without retentive slots (p < 0.05). Short fibre-reinforced-composite with retentive slot cavities had significantly higher fracture resistance values compared with the other test groups (p < 0.05). CONCLUSIONS: The preparation of retention slots may increase the fracture resistance of endodontically-treated teeth, especially, when restored with short fibre-reinforced composite. The use of short fibre-reinforced composite with retentive slots could be an alternative technique to prevent cuspal fracture on endodontically-treated teeth with MOD cavity.

Comparative study of radiopacity of resin-based and glass ionomer-based bulk-fill restoratives using digital radiography.

This study investigated the radiopacity values of glass ionomer- and resin-based bulk-fill restoratives of different thicknesses using digital radiography. Two glass ionomer-based and three resin-based bulk-fill restoratives, and a conventional composite were studied. Five disc-shaped specimens were prepared from each of these materials at three different thicknesses; specimens of enamel and dentin with the same thicknesses were also prepared. Materials were placed over a complementary metal oxide-semiconductor sensor together with the tooth specimen and an aluminum step-wedge, and then exposed using a dental X-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs), which were converted to equivalent aluminum thicknesses. Two-way ANOVA was used to investigate the significance of differences among the groups. The GCP Glass Fill specimens showed the lowest radiopacity values, and the Quixfil specimens had the highest values. All materials had higher radiopacity values than enamel and dentin, except for GCP Glass Fill, which had a radiopacity similar to that of enamel. The resin-based bulk-fill restoratives had significantly higher radiopacity values than glass ionomer-based restoratives. All of the tested materials showed radiopacity values higher than that of dentin, as recommended by the ISO.

Spectrophotometric analysis of crown discoloration induced by various antibiotic pastes used in revascularization.

INTRODUCTION: Antibiotic pastes are used for disinfection in regenerative endodontic procedures. This study evaluated the crown discoloration induced by various antibiotic pastes including the mixture of metronidazole and ciprofloxacin with minocycline, doxycycline, amoxicillin, or cefaclor. METHODS: Seventy extracted bovine incisors were sectioned to obtain a standardized root length of 10 mm above the facial cementoenamel junction. After pulp tissue removal, irrigation with sodium hypochlorite and the placement of temporary filling material and cotton pellet were performed from the apical aspect. The specimens were then randomly divided into 7 groups (n = 10 for each group), and each group received the following antibiotic paste fillings: no filling (control group), calcium hydroxide, double antibiotic paste (DAP), triple antibiotic paste (TAP) with minocycline, TAP with doxycycline, TAP with amoxicillin, and TAP with cefaclor. Spectrophotometric readings were obtained on the buccal surfaces of the crown on day 1 to week 3 after filling, and the ΔE value was calculated. Data were analyzed with 2-way analysis of variance and the Tukey post hoc tests (P = .05), and the human perceptibility threshold was set to 3.7. RESULTS: TAP with minocycline, doxycycline, and cefaclor induced more coronal discoloration compared with the control group (P < .05). The control, calcium hydroxide, and DAP groups showed no color changes exceeding the perceptibility threshold at all time points. CONCLUSIONS: The results indicated that all antibiotic pastes, except DAP, induced crown discoloration.

Does oral hygiene trigger carotid artery intima-media thickness?

BACKGROUND AND PURPOSE: The aim of this study was to evaluate whether poor oral hygiene is associated with the intima-media thickness of the carotid arteries, which is one of the predictors of future progression of subclinical atherosclerosis. METHODS: We selected 108 patients during periodontal examinations according to their oral hygiene. The patients had no history of atherosclerotic disease. The results of carotid artery B-mode ultrasonography examinations were analyzed at baseline and after a mean of 7.8 months. Patients were scored on the DMFT index for the number of decayed (D), missing (M), and filled (F) teeth (T). We also used the Silness-Loe plaque index (SLI) to evaluate oral hygiene and dental plaque. The patients were divided into 2 groups according to DMFT and SLI criteria. Group I had a DMFT index of 0 to 3 and an SLI score of 0 or 1; group II had a DMFT index of 4 to 28 and an SLI score of 2 or 3. RESULTS: Dental status and oral hygiene were significantly associated with carotid artery intima-media thickness. Patients with increasing DMFT and SLI indices were correlated with intima-media thickness of the carotid artery. CONCLUSIONS: Chronic poor oral hygiene and tooth loss are related to subclinical atherosclerotic changes in the carotid arteries and might be indicative of future progression of atherosclerosis.

Carotid and popliteal artery intima-media thickness in patients with poor oral hygiene and the association with acute-phase reactants.

PURPOSE: The aim of this study was to evaluate whether poor oral hygiene is associated with carotid and popliteal arterial intima-media thickness, which is one of the predictors of future progression of sub-clinical atherosclerosis, and highsensitivity C-reactive protein (hsCRP) and fibrinogen levels. METHODS: A specialised dentist checked the patients and selected 550 patients during periodontal examinations, according to their oral hygiene. The patients had no history of atherosclerotic disease. Carotid and popliteal artery B-mode ultrasonographic examinations and hsCRP and fibrinogen levels were analysed at baseline and after a mean of 6.2 months. The patients were scored on the DMFT index for the number of decayed (D), missing (M), and filled (F) teeth (T). We also used the Silness-Loe plaque index (SLI) to evaluate oral hygiene and dental plaque. The patients were divided into two groups using the DMFT and SLI criteria. Group I had a DMFT index score from 0 to 3 and SLI index score of 0 or 1. Group II had a DMFT index score from 4 to 28 and SLI index score of 2 or 3. RESULTS: A significant association was observed between dental status, oral hygiene, carotid and popliteal artery intima-media thickness and hsCRP level. Patients with increasing DMFT and SLI scores correlated with increasing carotid artery intima-media thickness. CONCLUSIONS: The results clearly showed that chronic poor oral hygiene and tooth loss are related to sub-clinical atherosclerotic changes in the carotid arteries and may be indicative of future progression of atherosclerosis.