The effect of immersion disinfection procedures on dimensional stability of two elastomeric impression materials

The aim of this study was to determine the effect of immersion disinfection procedures on the dimensional stability of two elastomeric impression materials. Impressions of a stainless steel die were made with polyether (PE) and with additionpolymerized silicone rubber (PVS). The test specimens underwent disinfection treatment by immersion in two commercially available solutions containing quaternary ammonium compounds (Sterigum Powder, SP) and glutaraldehyde plus an amino derivative (MD520, MD), respectively. The impressions were measured at 4 different time points: before any disinfection treatment (T0); after the first disinfection (T1); 6 hours after the first disinfection (T2); after the second disinfection, carried out 6 hours after the first one (T3). Impressions which were not disinfected served as controls. When both impression materials were disinfected with SP, significant differences were detected among all measurements (P < 0.0001), with the exception of T2 vs T3 (P > 0.05). On the other hand, when MD was used, significant differences were found when T0 measurement was compared to T1, T2 and T3 measurements (P = 0.0043 for PE, and P = 0.0014 for PVS). The dimensional change of all material/disinfectant combinations was always ≤0.5%. Therefore, the effects of immersion disinfection on the dimension of elastomers in SP or MD are not clinically relevan

Fiber Post Removal: Comparative Study Using a New Post Concept

Objectives: To evaluate the time required to remove endodontic posts made of quartz and glass fibers, and compare them to a new glass fiber post designed for easy removal on the basis of efficiency and tooth damages. Methods: 40 human single-rooted teeth were treated endodontically and randomly assigned to four fiber posts groups: 1) was restored with Premier#90 (Innotech); 2) with DT#2 Lightpost (Dentsply); 3) with Unicore#3 (Ultradent); 4) with a special, soft-cored “S” glass fiber post ER-Prosthetic#3 (Overfibers). An impression of the canal was taken prior post cementation. The posts were luted with Panavia F and adhesive (Kuraray). All the specimens were mounted in a dental simulation unit to reproduce the difficulty of clinical conditions. The fiber posts were removed using a diamond bur /Gates and Largo reamer combination. The teeth were examined radiographycally 2 times seeking for cement, fiber composite debris and tooth damage. After post removal, another impression of the canal was taken for each tooth to evaluate the canal enlargement. Then, the specimens were fractured and observed microscopically. Results: No significant differences were found among the conventional posts (groups 1-3) as regards removal time and dental tissue loss (Kruskal-Wallis, alpha=0.05). The new soft-core concept applied to the ER-Prosthetics allowed a mean rank removal time significantly lower (P=0.001) than the mean rank of group 1-3 posts (Dunn's test). The canal enlargement was significantly lower with ER posts. Root perforation occurred in groups 1 to 3, but none was recorded in group 4. Conclusion: Removal of posts avoiding dental tissue loss is a difficult task when performed in simulated clinical conditions. A new post type conceived to be removed safely in a short time was very effective to reduce the removal time without tooth damages. Further studies will be necessary to validate this new concept

Surface treatments for titanium implants

The implant surface is considered one of the most important factors for osteointegration. A factor that proved to be crucial for a better, faster osteointegration is surface roughness. It has been widely shown that an increase in roughness corresponds to a better microretention between implant and bone macromolecules. Titanium surface can be prepared with different techniques in order to obtain an optimal degree of surface roughness, an increase of TiO2 thickness, or even to create a coating of osteoconductive material. This article describes the most widely used and investigated techniques to modify a titanium implant surface: Addition techniques: titanium oxide layer thickening, TPS (Titanium Plasma Spray), hydroxyapatite or calcium phosphate coatings; Subtraction techniques: sandblasting, acid etching, SLA, electropolishing, mechanical polishing, and electrochemical anodization; Surface modifications: ion implantation, laser treatment, electrothermal treatment

Prosthetic rehabilitation of a young patient affected by Ectodermal Dysplasia with the new Eclipse Resin System

Ectodermal dysplasia is a genetic disease caused by incorrect development of the epidermis and cutaneous adnexa (for example hair, nails and sweat glands). It is often associated with skeletal and dental development anomalies. The main clinical manifestations of these syndromes are hypotrichosis, hypohydrosis and hypodontia or anodontia. Polymethyl methacrylate (PMMA) is still the most frequently used material in denture bases, but it can lead to irritation, inflammation and allergic reactions in the oral mucosa, due to the release of residual monomers. This clinical report describes a case of Hypohydrotic Ectodermal Dysplasia, rehabilitated with removable dentures made with a new monomer-free, light-curing resin (Eclipse, Dentsply International, York, PA – USA)

Cutting efficency of a new diamond bur for tooth preparation

Objectives: The aim of this study is to compare the cutting efficiency of a recently introduced diamond bur (314.S-6878.016, Komet Brasseler) for tooth preparation with its conventional variant (314.6878.016). Both burs have the same diameter, profile and diamond grains (160µm), but the 6878 have a polygonal section at the cutting portion level; this is claimed to have a percussion effect which can improve the hard tissue removal. Materials and methods: four burs from each type have been selected. Tablets made of human tooth fragments embedded in epoxy resin (4 to 1 w/w ratio) were used as test specimens. Their abrasion resistance is about 14% higher than that of the dentin. The burs were mounted on a turbine (Hi-Power M, Castellini) and operated under water spray (50 ml/min) applying a 1 N force interrupted for 0.2 seconds 30 times per minute. Each bur carried out 25 passages on each tablet, which was abraded 0.5 mm in depth and 5 mm in height. Two tablets for each bur were used. Cutting efficiency was measured in µg of material removed per second by weighing the tablets before and after five consecutive passages. After the test, the burs were observed under the SEM. Results: the cutting efficiency of the two burs was similar, 1.130.014 and 1.1280.017 for S-6878 and conventional 6878, respectively. The difference was not significant (P=0.915. However, the S-6878 showed a greater efficiency during the first third of the whole working cycle, whereas the conventional type was better in the last third. Conclusions: the polygonal S-6878 bur is very effective during the initial phases of tooth removal, but the crystal loss probably occurs very early, leading to a rapid decrease of the efficiency. The crystal loss, confirmed by SEM observation, is probably due to the high stress caused by the polygonal design

Introduction of a system for choosing and placing the anterior teeth of complete dentures.

Aim: The correct choice and placement of artificial teeth play an important role for the success when a patient is rehabilitated with a complete denture; so most of the issue of the esthetics of a complete denture depends on the correct tooth position and the right choice of the artificial anterior teeth. The aim of this poster is to introduce a new system, Dental Veneers Selection Form, (Dental VSF) (registered in: European Patent Bulletin. EP2759278 Device and methods for manufacturing dental prostheses. 31/2014: 204. Available at https://register.epo.org/espacenet/regviewer?AP=14000336&CY=EP&LG=en&DB=R) for choosing and positioning artificial teeth in the anterior region of complete dentures. Methods: The Dental VSF system is a system consisting of 18 maxillary and 6 mandibular anterior molds. The molds differ, exactly like the traditional ones present on the market, in size and shape. The peculiarity of the system is that the six teeth of each mold are represented by veneers, with intact incisal edges, and they are connected to each other on the lingual surface by a fiber that allows to each veneer some degree of movement. During the esthetic and phonetic test it’s possible to choose the most suitable mold in size and form, and, after removing the anterior wax rim, from canine to canine, to place the chosen mold, to give the desired overjet and overbite, to change the tilt of a singular tooth for individualizing the denture with some characterization. After the aesthetic and phonetic test, the technician makes a silicon template in order to record all the information sent by the dentist and in order to be able to place the teeth of the dental mold corresponding to that chosen with the Dental VSF system. Results: The Dental VSF system allows the dentist to not delegate the choice of most suitable mold to the dental technician, but to choose it directly on the face of the patient, trying on the different ones without having to work the heated wax. Moreover, the system allows to involve directly the patient about the shape and size of the teeth, and also about the overbite and any individual characterizations. The use of the Dental VSF system may be extended to implant supported dentures and to CAD-CAM technology: the assembly may be scanned and the scanned image may be used to design a screw-retained denture or a Toronto bridge. Conclusions : The Dental VSF can be an useful system to try simply the anterior maxillary and mandibular molds, different in shape and size, and at the same time to change the buccal-palatal inclination of each tooth