Resin-Bonded Prosthesis in Posterior Area to Prevent Early Marginal Bone Resorption in Implants Placed at Tissue Level

Aim: To evaluate the effect of the resin-bonded prosthesis (Maryland bridge) on marginal bone remodeling of implants placed at the tissue level in the posterior region. Methods: Consecutive healthy patients (n = 46) were included in this clinical study. Flapless not-submerged implants were placed with cover screws exposed and positioned approximately 0.5 mm above tissue level. Patients received the implant and a temporary resin-bonded prosthesis (RBP) (n = 22) or only the implant (n = 24). The RBPs were kept in place for 3 months and removed before impressions. The implants received a custom-made abutment and provisional resin crowns followed by definitive cemented metal-ceramic crowns after 2-3 weeks. The marginal bone level (MBL) was evaluated in a single-blind condition on scanned periapical radiographs and assessed mesially and distally (MBL-M/MBL-D). The bone levels of adjacent teeth (CEJ-M/CEJ-D) and the modification of the area between the implant and the mesial/distal teeth (Area-M/Area-D) were measured. All measurements were made at 1, 3 (pre-loading time) and 12 months (post-loading time). Linear regression models were fitted to evaluate the existence of any significant difference. Results: A total of 44 patients (20 Female, 24 Male; Mean age: 53.9 +/- 10.3) completed the study. Two patients were excluded for fractured RBP or de-bonding. The drop-out was of 4.3%. After 12 months, all implants were free from complications. No peri-implantitis or mucositis were observed. The RBP group showed the most stable MBL at 12 months (-0.07 +/- 0.41), statistically different from the non-RBP group (-0.67 +/- 0.52). CEJ-M and CEJ-D were stable in both groups. Conclusion: The proposed approach of the use of RBP creates a more stable marginal bone level around implants placed at the tissue level, resulting in a reliable technique to protect bone tissue from mechanical and occlusal trauma during the healing period and osteointegration

Reciprocating System for Secondary Root Canal Treatment of Oval Canals: CBCT, X-rays for Remnant Detection and Their Identification with ESEM and EDX

Aim of the study: to evaluate root filling remnants after secondary root canal treatments (SRCTs) of oval-shaped canals with X-rays and cone beam computed tomography (CBCT). The SRCTs were performed using reciprocating NiTi instruments. Methods: Single-rooted teeth (N = 64) were randomly treated with Reciproc Blue (RB) and filled with AH Plus/single cone (SC group) or AH Plus/Guttafusion (GF group). After seven days of storage in HBSS (Hanks balanced salt solution), Gates Glidden burs #2/3 and RB #25 and #40 were used for the SRCTs. The time to complete the procedure was measured. X-rays and CBCT were used to calculate, respectively, the area and the volume occupied by the remnants in the coronal, middle, and apical thirds of each canal. Environmental scanning electron microscopy (ESEM) and energy dispersive X-ray spectroscopy (EDX) were used for qualitative evaluation and morphology composition of the remnants in sectioned roots. A statistical analysis was performed using Sigma Plot (version 13, IBM, Armonk, NY, USA). The study was designed according to PRILE guidelines. Results: After the SRCTs, the middle thirds of the root canals showed the presence of remnants in both groups, as demonstrated by X-rays and CBCT. The GF group showed a statistically significant higher volume of remnants than the SC Group only in the middle third. The ESEM supported by the EDX revealed the remnant composition by the detection of trace elements of sealer and gutta-percha in all root canals. Conclusion: The study demonstrated that the middle third of root canals is a critical region where remnants were packed and spread in the buccal-lingual sides of canals. ESEM-EDX detected a fine layer of filling remnants in all root thirds, suggesting a larger canal contamination than the X-rays and CBCT examinations revealed

Correlation between Microleakage and Tubules Penetration of an Endodontic Sealer

Objective: The aim of the study was to verify the existence of a correlation between fluid filtration and tubular penetration of an endodontic sealer. Methods: Ten pairs of maxillary incisors with a single root canal, circular cross-section, similar sizes and dimensions were selected from a collection. Teeth from each pair were randomly divided in 2 groups. All canals were instrumented using NiTi WaveOne Primary instrument (#25) (Dentsply, Maillefer). In the group 1 all canals were irrigated with 1 mL of 5,25% NaOCl for 30s (Ogna, Muggi\uf2, Italy), followed by 0.5 mL of 10% EDTA for 30 s (Ogna). In the group 2 it\u2019s used the same protocol but without the EDTA. A final irrigation of 2.0 mL 5,25% NaOCl for 3m was performed. Root filling was performed with Thermafil-obturators (Dentsply Tulsa, Tulsa, OK) with TopSeal (Dentsply, Maillefer) mixed with 0.1 wt% alizarin to evaluate the penetration depth of the sealer into tubules with confocal microscope (Leica, Wetzlar, Germany). Microleakage i.e. the volume of a calcein solution infiltrated into the root canal and tubules were evaluated using a digital fluid flow-meter and a confocal microscope. Results: Confocal microscopy showed a penetration of the sealer into tubules in group 1 of approx. 370 \u3bcm at 3 mm from the apex and 630 \u3bcm at 5 mm while in group 2 of approx. 22 \u3bcm at 3 mm and 37 \u3bcm at 5 mm from the apex. The volume of the infiltrated fluid was 0.353 x 10-4 mm3 for group 1 and 0.397 x 10-4 mm3 for group 2. The data of calcein penetration into the root canal were in agreement with the fluid filtration results. Conclusion: A correlation seems to be present between sealer penetration into dentinal tubules and sealability of Thermafil-obturators and TopSeal in root canal shaped with WaveOne Primary file

Arginine-Based Toothpaste Induces Calcium-Phosphates Deposits on Dentin Surface and Tubules

Objective: To test the ability of a calcium carbonate-containing toothpaste for dentinal hypersensitivity to occlude the exposed open tubules of dentin surface. Method: Dentine slices (0.9±0.1 thick) and crown segments (1.5±0.3 cm thick) from human third molars were used. Elmex Sensitive Professional toothpaste (GABA Int AG, Therwill, Switzerland) containing as main active ingredients arginine (8%), sodium monofluorophosphate (1450 ppm Fˉ) and calcium carbonate, was applied (3 min) on coronal dentin surface. Fluid flow/permeation through the dentin thickness (i.e. permeability or hydraulic conductance, Lp in microliters/min) was evaluated using a digital fluid flow-meter after smear layer formation, after EDTA treatment, after Elmex toothpaste treatment (t=0) and after soaking for 1, 7, 28 days in simulated body fluid (HBSS). Tubules occlusion, elemental analysis and mineral content were studied by ESEM-EDX. Toothpaste penetration inside dentinal tubules was analyzed by laser confocal microscopy using calcein as tracer. Result: Lp of EDTA-treated dentin significantly decreased after treatment with Elmex toothpaste (-73,32% at t=0) and after soaking in HBSS the Lp values further decreased (-77,69% at 24h, -78,18% at 7d, -83,01% at 28d). After 24h and 7d in HBSS, ESEM on Elmex-treated dentin showed the presence of precipitates on dentin surface and in the dentinal tubules; EDX revealed N (from arginine) and F (from monofluorophosphate) of the toothpaste. Lp remained significantly lower (-78,18%) than EDTA- treated control dentin. After 28d in HBSS, a calcium phosphate layer was detected on dentin surface so tubules were not visible. EDX detected F and no N. No CaP deposits were found on EDTA-treated dentin soaked in HBSS. Confocal microscopy showed an average penetration depth of the toothpaste into the dentinal tubules of ~85 microns. Conclusion: Elmex sensitive toothpaste can reduce the fluid movement into the exposed dentinal tubules and favour the formation of calcium phosphate minerals

Arginine-calcium carbonate professional treatment for tubules occlusion in hypersensitive dentin

Objective: To test the tubules occlusion of an arginine-based professional treatment for hypersensitive dentin. Method: Dentin segments/discs were prepared from erupted sound molars. Elmex sensitive professional desensitizing paste (GABA Int. by Colgate Oral Pharmaceuticals, Dallas, USA) containing arginine 8% and calcium carbonate was applied on EDTA-treated dentin for 20s at 1000rpm using a prophy cup, following the manufacturer directions. The excess was removed using a microbrush then the dentin disc was gently rinsed and immersed in 20mL of simulated body fluid (Hank\u2019s Balanced Salt Solution, HBSS) at 37\ub0C. After 24h, 7 and 28d the dentin surface was analyzed by ESEM-EDX to evaluate the tubules occlusion and the mineral content. Elmex paste mixed with calcein solution 1% was used to evaluate its penetration depth into the tubules by confocal microscopy. Result: After 24h in HBSS, ESEM-EDX analyses on Elmex-treated dentin showed the presence of precipitates on dentin surface and in the dentinal tubules, relevant amount of N(16-19 wt%, demonstrating the presence of arginine and Ca/P molar ratio 653.0. Confocal microscopy showed a penetration of the paste into the dentinal tubules to a mean depth of approx 50 microns (maximum depth penetration 100 microns). ESEM showed the presence of many tubules still obturated by material after 7d in HBSS; EDX found N (approx 19 wt%) and Ca/P molar ratio was 2.43. After 28d in HBSS a coating of calcium phosphate deposits covered the dentin surface so tubules were not visible; EDX detected N (6-7 wt%) and showed a Ca/P molar ratio of 2.14. Conclusion: Elmex sensitive professional paste can obturate the dentinal tubules and adhere to the dentin surface. Evidences of mineralizing properties have been found by the deposition of calcium and phosphate-containing minerals within the dentinal tubules and the formation of a calcium phosphate protective layer on the dentin surface

Spectrophotometric analysis of crown discoloration induced by MTA- and ZnOE-based sealers

Crown discoloration can be induced by root canal sealer remnants following root canal treatment. OBJECTIVE: The aim of this study was to evaluate chromatic alterations in human tooth crowns induced by a Mineral Trioxide Aggregate-based sealer (MTA Fillapex(®) and a commonly used ZnOE-based sealer (Roth-811). The tested null hypothesis was that the application of the materials did not induce clinically perceptible crown discoloration (Ho: CIE color difference ΔE<3.7). MATERIAL AND METHODS: Forty five fully developed, intact, mandibular third molars were sectioned 1 mm below the cemento-enamel junction. The pulp chambers were chemomechanically debrided via the cervical access. The specimens were randomly assigned into three groups Group 1: MTA Fillapex, Group 2: Roth 811, Group 3: Negative control (unfilled) and immersed in individually marked vials containing distilled water up to the cervix (37±1º C). The spectral reflectance lines were recorded by utilizing a UV-VIS spectrophotometer equipped with integration sphere in the visual spectrum at baseline, 1 week, 1 and 3 months after material placement. Data were transformed into values of the CIE L*a*b* color system and the corresponding ΔE values were calculated. Statistical analysis was performed using two-way mixed ANOVA models, at p=0.05 level of significance. RESULTS: A statistically significant increase in a* and b* chromatic parameters of the MTA Fillapex Group was measured. However, ΔE values did not exceed the human eye perceptibility threshold (set at ΔE<3.7) during the experimental period (ΔEt3=2.88). In Roth-811 Group, a statistically significant decrease in L* and a statistically significant increase in a* and b* chromatic parameters was measured, during all observation periods. Resultant ΔE values exceeded the human eye perceptibility threshold after 1 week (ΔEt1=5.65). CONCLUSIONS: Application of MTA Fillapex in tooth crowns resulted in minimal color alterations, while Roth 811 induced severe discoloration, in vitro. It could be suggested that, in terms of aesthetics, the use of MTA Fillapex appears to be favorable

Atherosclerosis in young Brazilians suffering violent deaths: a pathological study

<p>Abstract</p> <p>Background</p> <p>Atherosclerosis is the leading cause of coronary heart disease and ischemic stroke, which can cause sudden death in adulthood. In general, the clinical manifestations of cardiovascular diseases are caused by atherosclerosis, which is a process that starts during middle age. More recent studies indicate that the atherosclerotic process begins during childhood.</p> <p>Methods</p> <p>To evaluate the extent of atherosclerotic disease in young Brazilians, we conducted a study of the pathological alterations in the major arteries of victims of violent death. Samples of the right carotid artery, left coronary artery, and thoracic aorta of young victims of violent death were analyzed and graded in accordance with the histological atherosclerotic lesion types proposed by the American Heart Association. Samples were collected from 100 individuals who had died from external causes, aged from 12 to 33 years.</p> <p>Results</p> <p>The majority of cases (83%) were male, and 66% of deaths were homicides caused by firearms. The median age was 20.0 years and mean body mass index was 20.9 kg/m². Of the right carotid artery specimens, 3% were normal, 55% had type I, 40% had type II, 1% had type III, and 1% had type IV atherosclerotic lesions. Of the left coronary artery specimens, 5% were normal, 48% had type I, 41% had type II, 3% had type III, and 3% had type IV lesions. Of the thoracic aorta specimens, none were normal, 13% had type I, 64% had type II, 22% had type III, and 1% had type IV lesions. Overall, 97.34% of arteries examined had some degree of atherosclerosis. The most common histological type was type II (foam cells). No thoracic aorta specimens were normal, and the coronary artery specimens had the most atherosclerosis.</p> <p>Conclusions</p> <p>Our results show a high prevalence of atherosclerotic lesions among young people in Brazil. Intervention should be undertaken to decrease the rate of sudden cardiac death in the adult population.</p

Fluoride content and recharge ability of five glassionomer dental materials

<p>Abstract</p> <p>Background</p> <p>The relationship between fluoride content and fluoride release for glass-ionomer cements is not well understood. The aim of this laboratory study was: to determine the fluoride concentrations at the surfaces of glass-ionomer materials with respect to different storage media and different pH environments; to examine the recharge ability of the materials after NaF immersion; and to assess the morphological changes at the material surfaces using scanning electron microscope and energy dispersive spectroscopic techniques (SEM/EDS).</p> <p>Methods</p> <p>Five glass-ionomer materials, Fuji Triage (FT), Fuji II LC (FII), Fuji VIII (FVIII), Fuji IX GP (FIX), and Ketac N100 (KN), were analyzed in this study. Resin-based fluoride releasing material Helioseal F (HSF) was used as a comparison material. The sample consisted of 120 cured cement disks (n = 20 disks of each tested material, 10 × 1.5 mm). Five disks of each material were stored in 4 different storage media (I- saline, II- acidic solution ph = 2.5, III- acid solution ph = 5.5, IV- NaF solution (c = 500/106). After 7 days, two disks of each material were transferred from media I, II and III to the NaF solution for 3 min. EDS analysis was conducted in 3 randomly selected spots of each experimental disk. SEM was used to determine morphological characteristics of the material surface. Differences between the experimental groups have been analyzed using Student's t-test with the level of significance set at p < 0.001.</p> <p>Results</p> <p>FT showed the highest fluoride content at the surface of the material. The lowest amounts of fluoride ions were detected at the surfaces of the FT disks stored at low pH environments, and this difference was statistically significant (p < 0.001). Glass-ionomers showed significantly higher fluoride concentrations when compared to the HSF (p < 0.001). After immersion in the NaF solution, fluoride concentrations at the surfaces of the disks increased when compared with previous storage media (FT>FVIII>KN>FII>FIX). SEM analysis of the surface morphology revealed numerous voids, cracks and microporosities in all experimental groups, except for KN and HSF. More homogenous material structure with more discrete cracks was observed in samples stored at neutral pH environment, compared to disks stored in acidic solutions.</p> <p>Conclusion</p> <p>The tested materials could be considered as promising dental materials with potential prophylactic characteristics due to their relatively high fluoride content, but also the ability to extensively reabsorb fluoride ions, especially in acidic environments.</p