Advances in alginate impression materials: a review

Alginate is an elastic irreversible hydrocolloid which has various applications in dentistry. The applications of alginates include making impressions of edentulous and partially edentulous arches, duplication of casts, and for making study models. Alginates possesses numerous vital properties such as hydrophilicity, ability to record finer details, elastic recovery and inexpensive; makes this material widely used in dentistry. Though alginate is the most commonly used impression material, it has some inherent disadvantages. Alginates contain low-density fine filler particles, which may arise in the form of dust and inhalation these dust particles may cause respiratory problems. Further, they are highly dimensionally unstable due to syneresis & imbibition. Besides, alginates do not adhere to non-perforated trays, low viscosity resulting in gag reflex in some patients, and the inability to identify the correct consistency to load. Several modifications were made in the composition of conventional alginates to address their shortcomings. This article reviewed various recent advances in the alginate impression materials and their performance

Self-sealing resin fixators in dentistry

Fixed indirect restorations bond to the prepared tooth surfaces with the use of a variety of luting agents depending upon the purpose of that rehabilitation. Success and failures of these restorations have been attributed to the quality of their bond with the tooth substrate. However, the advent of resin-based and self-adhesive resin luting agents have greatly changed this equation by altering the conventional bonding mechanisms and the durability of bond. The limited literature details of these self-adhesive resin luting agents require further exploration for the benefit of dental professionals. This review provides an overview of the composition, chemical interactions, favourable and unfavourable properties to be known for improving the scope of their utilization in dentistry

Corrosion in Titanium dental implants – a review

Titanium (Ti) is the most widely used biomaterial for dental implants as it exhibits excellent mechanical properties and biocompatibility. The biocompatibility of titanium is related to thin, protective surface titanium dioxide (TiO2) layer, which forms a boundary at the implant-biological medium interface, reducing its reactivity with the surrounding biological environment and prevents corrosion. However, the metallic materials used as implants are susceptible to corrosion due to variations in the internal electrolyte environment. The surface oxide layer can be destroyed during insertion of implant or micro-motion between implant and bone under loading conditions. The localized destruction causes corrosion of the implant and induces leak of metallic particles or ions into surrounding tissues. The presence of metallic particles in peri-implant soft and hard tissues may be due to frictional wear or corrosion, or simultaneous occurrence wear and corrosion which is known as tribocorrosion. The released metal ions may remain in the intercellular spaces near the site where they were released or may be taken up by macrophages, or they can migrate systemically. This review article highlights various aspects of corrosion, biological response to corrosion products and prevention of corrosion of titanium dental implants

Solubility of glass ionomer cement in various acidic beverages at different time intervals: an in vitro study

Background: Glass Ionomer is a widely used cement in dentistry for luting and restoration purposes. This cement leaches a large amount of fluoride ions leading to an increase in the early solubility and disintegration in the oral fluids. The solubility of the cement is further aggravated when it is exposed to an acidic medium. Aim: This study aimed to evaluate the solubility of glass ionomer cement (GIC) in various acidic beverages at different time intervals. Materials and Methods: Four commercially available beverages and distilled water was used as immersion media. The pH of the beverages was measured using a digital pH meter. Glass ionomer cement discs were prepared and immersed in beverages for 1 day, 24 hours and 7 days. After completing the immersion time in each beverage for a specific period, the specimens were retrieved and weighed. The solubility was calculated by subtracting the weight at the specific immersion period from the initial weight of the specimen.   Results: Immersion in distilled water demonstrated less solubility compared to immersion in acidic beverages. Among the acidic beverages, GIC immersed in MAAZA showed the maximum solubility compared to the other beverages. One-Way ANOVA displayed a significant difference (p=0.000) among the beverages at different time intervals. Conclusions: This study found that the GIC immersed in fruit juices with preservatives showed more solubility at all time intervals compared to the immersion in carbonated drinks

Surface modifications of dental implants: An overview

Osseointegration is the key for long term success of endosseous dental implants. Implant surface properties like surface roughness, surface topography, surface energy and surface composition are the major characters that influence the process of osseointegration. Several methods have been used to optimise implant surface roughness to increase surface area thereby improving the process of osseointegration. Blasting using alumina and titanium dioxide, acid treatment, anodization, and laser peeling are some of the subtractive methods used to optimize implant surface roughness. Additive methods used to coat HA onto the surface of endosseous implants include plasma sprayed HA, vacuum deposition technique, sol-gel and dip coating method, electrolytic process and nano-HA coating. Recently, biomimetic implant surfaces are produced with calcium phosphate coatings under physiological conditions. These coatings are also capable to act as vehicles for osteogenic agents like BMPs, GDFs and  biologically active drugs like bisphosphonates, gentamicin, tetracycline, etc.,. The methods used for surface modifications of endosseous dental implants are vast and continuously evolving with the recently developed technologies. This article gives an overview on various surface modifications and current trends followed in the field oral implantology

Disinfection of impression materials: A comprehensive review of disinfection methods

Impression making is one of the most common procedures that are performed by dentists in day-to-day practice. These impressions can act as vehicles of transmission and carry various types of microorganisms, which further cause diseases like Hepatitis B, C, HIV, Tuberculosis etc. This contamination and cross contamination of microorganisms can be prevented by disinfecting the impressions immediately after removing from the mouth and label them as disinfected. Usually the impressions are placed under running water to remove saliva and blood, but this will eliminate the disease-causing microorganisms, so a standard protocol to disinfect the impressions and casts should be known to dentists and dental personnel. Various methods of impression disinfection like chemical disinfection, Microwave, Autoclave, Ultraviolet radiation have been described in literature having their own advantages, disadvantages and effects on impression material and casts. Recently antimicrobials and nanoparticles have been incorporated into the impression material itself to make it self- disinfecting. This will not only disinfect the impression material from inside but also disinfect the impressions from the time it is inserted in patient’s mouth.  A broad search on the literature available was performed to provide knowledge about mechanism of action, concentration of usage along with commercial preparations available of different disinfectants. This review article will enhance the knowledge and improve the behavior of dental health care workers about impression disinfection

The effect of Fit-checking material and various subsequent cleaning methods on the wettability of the dentin surface: an in vitro study

Background: GC Fit-checker is a modified polyvinyl siloxane impression material exclusively used to check the internal fit and improve the marginal fit of indirect restorations. An unpolymerized organic film is known to be leftover on the bonding surfaces after the silicone disclosing procedure. Residual silicone film being hydrophobic may alter the wettability of the cement to the tooth/metal surface, thus having a detrimental effect on the bond strength and retention of the restoration.   Aim: This study aimed to evaluate the wetting of luting liquid (GIC) to tooth dentin surface after application of Fit-checker and evaluate the efficiency of various surface treatments in removing the residual silicone film. Materials and Methods: Extracted human molars were mounted on the acrylic block, and the tooth occlusal surface was ground flat till the dentin exposure. All the specimens were assigned into five groups: Group 1: without application of Fit-checker (control group); Group 2: without any surface treatment after peeling off Fit-checker; Group 3: surface treatment with wet pumice; Group 4: 37% phosphoric acid treatment; Group 5: 10% polyacrylic acid treatment. Later, Type 1 Glass Ionomer Cement (GIC) liquid drop was placed on the dentin and photographs were made horizontally using a standardized procedure. Contact angles were measured using AUTOCAD software. Obtained values were statistically analyzed using the One-way ANOVA test and Tukey’s Post hoc test. Samples of each group were examined using the scanning electron microscope. Results: Statistically significant difference was observed among all the groups except between Group 4 and Group 2 (p > 0.05). SEM images of various groups showed a significant difference in roughness patterns. Conclusion: Surface treatment with pumice and the rotary brush was an effective method among the three in cleaning the residual silicone film

Mineral Trioxide Aggregate: an overview of composition, properties and clinical applications

“Mineral trioxide aggregate” is a cementitious material, which is popular by its trade name MTA. It was first introduced in the year 1993 by Mohmoud Torabinejad at Loma Linda University in California, USA. MTA is a powder mixture of Portland cement clinker, bismuth oxide, and gypsum. It has gained a lot of importance in dentistry in recent years. This importance is because of its extensive use as apical restorative material as well as a medicament for Apexogenesis and Apexification treatment. As it sets by hydration process, the byproducts of insoluble calcium silicate hydrate and alkaline calcium hydroxide offer unique stability and potential to enhance hard tissue regeneration.  This article reviewed the composition, types, properties of MTA and also its applications in the practice of dentistry

An overview of composition, properties, and applications of Biodentine

A series of events leads to loss of tooth structure by dental caries, tooth wear and trauma, which is often replaced by inert dental materials that replace the bulk of the tooth. If pulp health is affected, a series of interventions need to be undertaken. Initially, the pulp vitality needs to be maintained. Later, elimination of infection and filling of the pulp space is necessary. When pulpal involvement occurs the choice of material has to change, and materials that interact with the pulp are indicated. Interactive materials used for dental procedures include calcium hydroxide in its various presentations and hydraulic calcium silicate cement.  Biodentine is a promising dentine substitute that has been recently introduced in dentistry. Although many other materials like Glass Ionomer Cement (GIC), composite and Mineral Trioxide Aggregate (MTA) are available for repair of dentin loss in tooth structure, none of them possesses ideal properties. Despite many advantages, MTA has been replaced by Biodentine, which is a new calcium silicate-based material, due to its limitations. It has good handling properties, short setting time, and improved mechanical properties. Biodentine was designed explicitly as a "dentine replacement," with applications ranging from endodontic repair to pulp capping

Evaluation of physico-mechanical properties of dental plaster modified with pulverized acrylic waste

Background: Dental plaster is most widely used to make temporary casts and as an investment medium during the fabrication of removable complete and partial denture prostheses. Dental plasters exhibit poor mechanical properties. Aim: This study aimed to evaluate the physico-mechanical properties of dental plaster modified with various concentrations of pulverized acrylic waste. Materials and Methods: A total of 120 specimens were fabricated using dental plaster and were divided into four groups of 30 specimens each to evaluate setting time, one-hour compressive strength, 24-hour compressive strength, and surface reproducibility. Each group was subdivided into five groups of six specimens (n=6), each with the incorporation of various concentrations of pulverized acrylic powder. The specimens incorporated with various concentrations of pulverized acrylic powder (0.5 wt%, 1.0 wt%, 5.0 wt% and 10.0 wt%) were considered as modified groups and the dental plaster with no additives was considered as a control group. The initial and final setting times were measured using a Gillmore needle apparatus, the compressive strength was measured using a universal testing machine, and the surface reproducibility was analyzed using a stereo microscope. The obtained data were subjected to statistical analysis using one-way ANOVA and post hoc analysis.   Results: The incorporation of 0.5 wt% resulted in more final and initial setting times. The one-hour and 24-hour compressive strengths of the dental plaster increased with increasing concentration of acrylic waste. Poor surface details were observed with an increase in the concentration of acrylic waste. Conclusions: The addition of acrylic waste resulted in an increase in the one-hour and 24-hour compressive strengths, decreased initial and final setting times, and poor surface reproducibility