Heat treatment during setting on properties of resin-based provisional-restorative materials

This journal suppl. entitled: Abstracts of the Academy of Dental Materials Annual Meeting, 8-11 October 2014 - Bologna, ItalyPURPOSE: To study the effect of heat treatment during setting on the physical properties of four resin-based provisional restorative materials. METHODS AND MATERIALS: Four commercial restorative resin materials were employed, namely Duralay (polymethyl methacrylate), Trim II (polyethyl methacrylate), Luxatemp (bis-acrylic composite) and Protemp 4 (bis-acrylic composite). Specimens were prepared at 23 °C, 37 °C or 60 °C in a water bath for evaluation of flexural strength, surface profile, color stability and marginal discrepancy. Flexural strength was determined by 3-point-bending test on each specimen after thermo-cycling (3000 cycles, between 5-55 °C), and its fractured surface was examined under scanning electron microscopy. Surface profile of the specimens was studied using atomic force microscopy. Color stability (ΔE*) was evaluated by comparing the color of the specimens before and after placed in coffee for 14 days. Standardized crowns were prepared for assessment of marginal discrepancy using a travelling microscope. RESULTS: Flexural strength of Trim II and Protemp 4 at 60 °C (Trim II: 51.52 ± 5.59 MPa, Protemp 4: 115.41 ± 12.76 MPa) were higher than those at 37 °C (Trim II: 43.61 ± 6.21 MPa, Protemp 4: 89.38 ± 8.59 MPa) and 23 °C (Trim II: 41.79 ± 5.37 MPa, Protemp 4: 87.50 ± 10.29 MPa) (p 0.05). Slight difference of surface morphology could be seen between different curing temperatures of all types of materials. Luxatemp and Protemp 4 have lower ΔE* compared with other materials, in all the three curing temperatures. Marginal discrepancy of Trim II, Luxatemp and Protemp 4 were higher at 60 °C than those at 23 °C and 37 °C. CONCLUSION: Increase in curing temperature enhances flexural strength of certain resin-based acrylic provisional veneers; however, there is also an increase in the marginal discrepancy. Different curing temperature slightly altered the surface morphology and color stability of material, while different materials have obvious different properties in terms of surface morphology and color stability.published_or_final_versio

The assessment of 5-hydroxytryptamine on the haemodynamic changes and platelet aggragation on gastric mucosal blood flow in rats

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A survey of practices of tunnel preparation among dentists who attended the 100th FDI Annual World Dental Congress

AIM: To study the practice of tunnel restoration (TR) among dentists who attended the 100th World Dental Federation (FDI) Annual World Dental Congress (AWDC). METHODS: An anonymous questionnaire was administered to a sample of 150 dentists who attended the 100th FDI AWDC in 2012. The participants were asked about TR and their practice of TR. They were also asked to provide their years of dental practice and the countries in which they received their dental training. RESULTS: Fifteen respondents were not performing restoration, and they were excluded from analysis. Most respondents (123/135) practiced general dentistry. Their basic dental training was from 46 countries and regions. Most of them (n = 117, 87%) knew about TR, and 53% (n = 71) practiced it. There were 12 dentists (9%) who had performed more than 10 TRs in the previous 12 months. Practice of TR among dentists who graduated more than 10 years previously was more common (odds ratio 5.87-5.98) than those who graduated <3 years previously. CONCLUSIONS: The current study found that about half of the surveyed dentists practiced TR, although most of them knew about it. Tunnel restoration was performed more frequently among dentists who had more than 10 years of clinical experience.link_to_OA_fulltex

Comment on ‘Tumour-infiltrating inflammation and prognosis in colorectal cancer: systematic review and meta-analysis’

No abstract available

Bending and wrinkling as competing relaxation pathways for strained free-hanging films

An equilibrium phase diagram for the shape of compressively strained free-hanging films is developed by total strain energy minimization. For small strain gradients {\Delta}{\epsilon}, the film wrinkles, while for sufficiently large {\Delta}{\epsilon}, a phase transition from wrinkling to bending occurs. We consider competing relaxation mechanisms for free-hanging films, which have rolled up into tube structures, and we provide an upper limit for the maximum achievable number of tube rotations.Comment: 4 pages, 4 figure

Restoring proximal caries lesions conservatively with tunnel restorations

The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED) and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations.published_or_final_versio

Influence of the indirect restoration design on the fracture resistance: a finite element study

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Arresting rampant dental caries with silver diamine fluoride in a young teenager suffering from chronic oral graft versus host disease post-bone marrow transplantation: a case report

BACKGROUND: Rampant caries is an advanced and severe dental disease that affects multiple teeth. This case describes the management of rampant caries in a young teenager suffering from chronic oral graft versus host disease after allogeneic bone marrow transplantation. CASE PRESENTATION: A 14-year-old Chinese boy suffering from beta-thalassemia major was referred to the dental clinic for the management of rampant dental caries. An oral examination revealed pale conjunctiva, bruising of lips, and depapillation of tongue indicating an underlying condition of anemia. The poor oral condition due to topical and systemic immunosuppressants was seriously aggravated, and rampant caries developed rapidly, affecting all newly erupted, permanent teeth. The teeth were hypersensitive and halitosis was apparent. Strategies for oral health education and diet modification were given to the patient. Xylitol chewing gum was used to stimulate saliva flow to promote remineralization of teeth. Silver diamine fluoride was topically applied to arrest rampant caries and to relieve pain from hypersensitivity. Carious teeth with pulpal involvement were endodontically treated. Stainless steel crowns were provided on molars to restore chewing function, and polycarbonate crowns were placed on premolars, upper canines and incisors. CONCLUSION: This case report demonstrates success in treating a young teenager with severe rampant dental decay by contemporary caries control and preventive strategy.published_or_final_versio

Dental Biofilm and Laboratory Microbial Culture Models for Cariology Research

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