Marginal adaptation and performance of bioactive dental restorative materials in deciduous and young permanent teeth.

The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. The composite resin and the polyacid-modified composite had better marginal adaptation than the glass-ionomers, though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Resin-based materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits

Adaptabilnost različitih kanalnih punjenja za dentin korenskog kanala - analiza elektronski skeniranih mikrofotografija

Introduction. The aim of this in vitro study was to test and analyze the sealing ability of three endodontic materials used for permanent obturation, in between the dentin walls and the gutta-percha points, using a scanning electron microscope. Material and Methods. Forty-five recently extracted single-root teeth, treated by a step-back technique, were divided into three groups (15 teeth in each); the canals were filled with three different permanent obturation materials: N2 - zinc oxide root canal cement, Gutta Flow (Coltene), and Endomethasone N (Septodont). Their sealing ability and adhesive properties were analyzed using field emission gun scanning electron microscope, at the time when they were applied between the dentin walls of the canal and the gutta-percha. Results. The results of the scanning electron microscope analysis have shown that all the three sealers have good adhesion properties when used over the root canal walls in the apical third. Good adaptation of the filling used for the root canal walls in the middle and the cervical third was found only in teeth obturated using Gutta Flow, while samples obturated by N2 - zinc oxide root canal cement and Endomethasone showed the weakest adhesion, and greatest number of cracks between the sealer and the canal wall. Conclusion. When using a single-cone obturation technique, compared to other obturation materials, Gutta Flow shows considerably better adaptation to the root canal wall and the gutta-percha points in the apical, middle, and the cervical third of the root.Uvod. Cilj ove in vitro studije je testiranje i analiziranje sposobnosti zaptivanja tri različita endodontska materijala koji se upotrebljavaju za definitivno punjenje između dentinskih zidova i gutaperke poena, primenom elektronskog mikroskopa. Materijal i metode. Četrdeset pet ekstrahovanih jednokorenih zuba, tretiranih step-back tehnikom bili su podeljeni u tri grupe (po 15 zuba u svakoj od njih), kanali su bili ispunjeni trima različitim materijalima za definitivnu opturaciju kanala: cink-oksid eugenolom, Gutta Flow (Coltene) i Endomethasone N (Septodont). Elektronskim mikroiskopom sa emisijom polja analizirani su adhezivna sposobnost i zaptivanje materijala za punjenje između dentinskih zidova korencskog kanala i gutaperke. Rezultati. Analiza elektronski skeniranih mikrofotografija pokazala je da sva tri materijala imaju dobru adheziju karakterističnu za njihovu primenu na zidovima kanala korena u apikalnoj trećini. Dobra adaptacija punjenja za zidove kanala korena u srednje i cervikalne trećine pronađena je samo na uzorke opturisanih metodom Gutta Flow, a uzorci koji su bili opturisani sa cink-oksid eugenolom, i Endomethason-om N imali su najslabiju adheziju i najveće prisustvo pukotina između silera i zida kanala. Kada se primenjuje single-cone tehnika za opturaciju kanala, Gutta Flow pokazuje znatno bolju adaptaciju za zid korenskog kanala i gutaperke u apikalni deo kao i u srednjoj i cervikalnoj trećini korena u poređenju sa drugim materijalima za opturaciju kanala

Diode laser irradiation in endodontic therapy through cycles: In vitro study

Background/Aim: The aim of this in vitro study was to investigate the influence of irradiation cycles and resting periods, on thermal effects on the external root surface during root canal irradiation of two diode laser systems (940 nm and 975 nm), at output powers of 1 W and 2 W in continuous mode. In previous studies the rising of temperature above 7°C has been reported as biologically accepted to avoid periodontal damage on the external root surface. Material and Methods: Twenty human inferior incisors were randomly distributed into four groups, the 940 nm, and the 975 nm diode laser irradiation, both with an output power of 1 W and 2 W, in continuous mode. The thermographic camera was used to detect temperature variations on the external root surface. Digital radiography of the samples was made. Results: After three cycles of irradiation, at apical third of the root, mean temperature variation by 940 nm diode laser irradiation was 2.88°C for output power of 1 W, and 6.52°C for output power of 2 W. The 975 nm laser caused a higher temperature increase in the apical region, with temperature variation of 13.56°C by an output power of 1 W, and 30.60°C at 2 W, with a statistical significance of p ≤ 0.0001 between two laser systems compared for the same power. The resting periods of 20 s between cycles were enough to lower temperature under 7°C in the case of 1 W and 2 W for 940 nm diode laser, while for 975 nm laser, after three irradiation cycles overheating occurred at both output power rates. Conclusion: Three cycles irradiation of 940 nm diode laser, with resting periods of 20 seconds, allowed safe usage of 1 W and 2 W in CW for endodontic treatment. For 975 nm at a power rate of 1 W, the last resting period drop the temperature near the safe limit and it came under 7°C in a period less than a minute, while at the power of 2 W the resting periods were not long enough for the safe temperature decrease

Assessment of the impact of the addition of nanoparticles on the properties of glass–ionomer cements

The aim of the study was to evaluate the effects of incorporation of Al2O3, ZrO2 and TiO2 nanoparticles into glass–ionomer cements (GICs). Two different GICs were used in the study. Four groups were prepared for each material: the control group (without nanoparticles) and three groups modified by the incorporation of nanoparticles at 2, 5 or 10 wt %, respectively. Cements were mixed and placed in moulds (4 mm × 6 mm); after setting, the samples were stored in saline (one day and one week). Compressive strengths were measured and the morphology of the fractured surfaces was analyzed by scanning electron microscopy. The elements released into the storage solutions were determined by Inductively coupled plasma-optical emission spectrometry (ICP-OES). Addition of nanoparticles was found to alter the appearance of cements as examined by scanning electron microscopy. Compressive strength increased with the addition of ZrO2 and especially TiO2 nanoparticles, whereas the addition of Al2O3 nanoparticles generally weakened the cements. The ion release profile of the modified cements was the same in all cases. The addition of Al2O3, ZrO2 and TiO2 nanoparticles into GICs is beneficial, since it leads to reduction of the microscopic voids in the set cement. Of these, the use of ZrO2 and TiO2 nanoparticles also led to increased compressive strength. Nanoparticles did not release detectable levels of ions (Al, Zr or Ti), which makes them suitable for clinical use

A Preliminary Study of the Water Movement Across Dentin Bonded to Glass-Ionomer Cements

Svrha ovog istraživanja bila je ispitati kako djeluje pomicanje vode po površini dentina vezanog za konvencionalne stakleno-ionomerne cemente. Materijal i postupci: Na ekstrahiranim trećim molarima bili su pripremljeni kaviteti petog razreda ispunjeni konvencionalnim stakleno-ionomernim cementom Fuji IX. Zatim je dio uzoraka bio jedan mjesec uronjen u umjetnu slinu, a dio 18 mjeseci. Nakon toga roka razrezani su longitudinalno i analizirani SEM-om (sekundarnim i „backscattered“ načinom) te EDAX-om. Rezultati: Nakon 18 mjeseci u materijalu su bile uočene sferične strukture kod spoja tvrdog dentina. Prazni prostori u blizini spoja tradicionalnih stakleno-ionomera i dentina uglavnom su bili u obliku „ljuske jajeta“ (iako je bilo i čvrstih). To je najvjerojatnije rezultat daljnjeg stvrdnjavanja u praznim prostorima originalnog polialkenoatnog matriksa, a događa se zbog difuzije vode iz vlažnog dentina. EDAX-ovom analizom potvrđeno je da su te formacije sastavljene od velike količine stroncija, silikata i aluminijia. Zaključak: Opisane sferične formacije mogle bi poboljšati kompresivne snage uočene kod starijih ispuna s konvencionalnim stakleno-ionomernim cementom.Objectives: The purpose of this study was to examine the effects of the water movement across dentin bonded to conventional glass-ionomer cements. Material and method: Class V cavities were prepared on extracted permanent third molar teeth, filled with conventional glass-ionomer cement Fuji IX and stored in artificial saliva for one and 18 months. After the storage time interval, the teeth were sectioned longitudinally and examined by SEM (in secondary and backscattered electron mode) and EDAX. Results: Spherical structures were noted in the material adjacent to the interface with the hard dental substances after 18 months. The air voids found next to the interface between the traditional glass-ionomer cements and dentin are mainly “egg-shell-like” (although, solid ones were also found). They are probably a result of the continuation of the setting reaction in the air voids of the original polyalkenoate matrix, which appears because of water diffusion from the humid dentin. The EDAX analysis proved that these formations consist of high quantity of strontium, silica and aluminium. Conclusions: The described spherical formations may lead to improvement of the compressive strength, which is found in old restorations with conventional glass-ionomer cements

Component release and mechanical properties of endodontic sealers following incorporation of antimicrobial agents

Root canal sealers with antimicrobial activity are highly beneficial; therefore, their antimicrobial properties could be improved by incorporation of antimicrobial agents. In the present study, the release of the quaternary ammonium compounds from endodontic sealers admixed with either benzalkonium chloride (BC) or cetylpyridinium chloride (CPC) at loadings of 2% wt was monitored. The effect of these additives on the compressive strengths and their release from the sealers was determined after 1 and 4 weeks. All of the materials studied were found to be capable of releasing antimicrobial additive in useful quantities. The release of CPC occurred to a statistically significant greater extent than BC for all materials. The addition of both BC and CPC generally decreased the compressive strength of all the endodontic sealers, with the exception of CPC in AH Plus, where the compressive strength was significantly increased. This suggests that, for these endodontic sealers, the antimicrobial additives alter the setting chemistry. AH Plus is an epoxy-based material cured with an amine, and in this case the increase in compressive strength with CPC is attributed to an enhanced cure reaction with this system. In all other cases, the additive inhibited the cure reaction to a greater or lesser extent

Usage of bioactive cement in vital pulp cell simulation-report of two cases

Introduction: Biodentine®, new bioactive cement ( Septodont, St.Maur-pass-Fosses, France), was recently launched on the dental market as a dentin substitute.It is biocompatible and capable of inducing the apossition of reactionary dentin by stimulating the odontoblast activity and reparative dentin by induction of the cell differentiation. During the setting reaction of the cement, ions of calcium hydroxide are released. Biodentine® can be used in pulpotomy of teeth with incomplete root formation. Aim of the study: to show the effect of Biodentine® in apexogenesis stimulation in immature permanent teeth Material and method: the study reports two cases of pulpotomy treatment of immature permanent teeth: a 9-year-old patient with horizontal fracture on the enamel and dentin with pulp exposure on tooth #21; and an 8-year-old patient with deep carious lesion on the tooth #36. Results: the postoperative X-rays and the clinical data of the two patients, shows that there aren’t any side effects in the treatment with Biodentine®, but the most important is that the apexogenesis continue without any disruptions. Conclusion: Biodentine® caused satisfactory response of the pulp in both cases where we made pulpotomy and direct pulp capping. According to these results, as well as the number of many studies, it can be concluded that the Biodentine® is one of the most powerful bioactive cements that can be used in many procedures, including pulpotomy and direct pulp capping. Keywords: calcium-silicate cement, apexogenesis, immature permanent teeth, pulpotom

Evaluation of efficiency of polymerization, surface roughness, porosity and adaptation of flowable and sculptable bulk fill composite resins

A new category of commercial bulk fill composite resins (CRs) enables the placement of 4-mm-thick layers as an alternative to the traditional time-consuming incremental technique. The purpose of the present study was to compare the efficiency of the polymerization, adaptation and porosity of two high-viscosity ‘sculptable’ bulk fill CRs (Filtek™ Bulk Fill (3M™ ESPE, St. Paul, MN, USA) and Tetric EvoCeram® Bulk Fill (Ivoclar Vivadent AG, Schwan, Liechtenstein)) and two low-viscosity ‘flowable’ bulk fill CRs (SureFil® SDR™ flow (Dentsply Sirona, Charlotte, NC, USA) and Tetric EvoFlow® Bulk Fill (Ivoclar Vivadent AG, Schaan, Liechtenstein)). Cylindrical samples of the bulk fill CRs (4 mm height x 10 mm diameter) were analyzed by Fourier-transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Additionally, occlusal cavities were prepared in twelve extracted human molars and restored with the bulk fill CRs (n = 3 for each CR). The adaptation and porosity of the bulk fill CRs were evaluated by X-ray microcomputed tomography (microCT) with a 3D morphometric analysis, and the adaptation was also analyzed by scanning electron microscopy (SEM) on longitudinal vestibulo-oral sections of the restored teeth. The AFM analysis demonstrated that the surface roughness of the SureFil® SDR™ flow was higher than that of the Tetric EvoFlow® Bulk Fill and that the surface roughness of Filtek™ Bulk Fill was higher than that of Tetric EvoCeram® Bulk Fill. CT and SEM confirmed that the flowable bulk fill CRs had excellent adaptation to the cavity walls. The 3D morphometric analysis showed the highest and lowest degrees of porosity in Filtek™ Bulk Fill and Tetric EvoFlow® Bulk Fill, respectively. In general, the flowable bulk fill CRs exhibited better adaptation, a higher efficiency of polymerization and lower porosity than the sculptable materials