Development of a Novel Formulation of Bioactive Glass Based Calcium Phosphate Cement for Bone Grafting

Particulate bone grafting material can travel from the implantation site and diminish the magnitude of required bone formation response and hence its effectiveness. An easily prepared moldable graft that rapidly sets rigid in situ would alleviate this problem and in this study, such an injectable bone graft material is presented. By combining calcium phosphate (CP) salts with a bioactive glass (BG) mixed with a 2.5% Na2HPO4 solution a novel BG-based calcium phosphate cement (CPC) is produced. Immersion in Tris buffer and simulated body fluid (SBF) solutions result in the rapid generation of octacalcium phosphate (OCP) and hydroxyapatite (HA) phases – a pre-requisite for “bioactivity”. Cement-conditioned media does not result in any cytotoxic potential with respect to MTT activity, DNA content, or alkaline phosphatase activity with an osteoblastic cell line. Application of the cement into standardized surgical defects in the minipig mandible results in short-term, moderate irritation at 3 and 6 weeks and complete replacement of cement with new bone at 12 weeks

Bond strength of repaired anterior composite resins: an in vitro study.

The objectives of this study were to investigate the repair potential of two commercially available composite resins in terms of bond strength, and the effectiveness of two commercially available adhesive systems used as intermediary materials in the repaired specimens. The repair strength of Helio Progress (HP) and Herculite XRV (XRV) was tested using two bonding agents: DenTASTIC (DT) and All Bond 2 (AB2). The effect of surface abrasion of specimens and the effect of time on repair strength were also investigated. Surface abrasion significantly improved the bond strength (P < 0.001) and the use of bonding agents further enhanced bond strength but not significantly. Use of bonding agents alone improved the repair bond strength significantly (P < 0.001). Repair of HP with HP after surface abrasion and application of DT produced the highest repair bond strength which was 99% of the cohesive strength of the control (unrepaired) specimens. Although there were some differences in the bond strength over the time period of the study (one month) none of these was statistically significant. It is concluded that surface abrasion coupled with the application of bonding agent produces the highest repair strength. It seems likely that clinically acceptable bond strengths are possible after repair of anterior composite resins

Developments in denture teeth to prevent softening by food solvents.

The effect of various food-simulating solvents on the hardness of denture teeth after varying storage times, using a Martens hardness test was determined. Martens hardness (HM) was assessed at baseline and during storage up to 1 month in distilled water (DW), peppermint oil (PO), heptane (HT) and 75% ethanol (ET) for four commercially-available denture teeth; Vivodent (VIV), Double-cross-linked Postaris (DCL), Orthosit (ORT), Candulor porcelain (POR) and two polymer based experimental denture teeth: Experimental 1 (EXP1); a hybrid nanocomposite with two different sized silanated filler particles and Experimental 2 (EXP2); containing an organic copolymer based upon urethanedimethacrylate and polymethyl methacrylate. Hardness [mean (sd)] at baseline was: VIV 142 (1), DCL 142 (1), ORT 209 (9), POR 2926 (101), EXP1 285 (11), and EXP2 146 (12). One-way ANOVA using Tukey's test on polymer-based materials showed that the hardness values of ORT and EXP1 were significantly higher than those of VIV, DCL and EXP2 (P < 0.05). Moreover, EXP1 had a significantly higher hardness value than ORT (P < 0.05). Except for EXP1, all polymer based materials showed a significant drop in hardness after storage in ET (P < 0.05). Specimens stored in water, heptane and peppermint oil showed minor fluctuations in hardness, which were not statistically significant

Rehabilitation of an Edentulous Maxilla in a Patient with Isolated Cleft Palate.

This article aims to discuss the use of short dental implants in cleft patients, the construction of an implant-retained obturator and the use of a Createch milled titanium bar with three Locator overdenture attachments incorporated within the bar. CPD/Clinical Relevance: Implant-retained obturators offer a possible solution for treating patients with isolated cleft palate who are struggling with dentures due to the unfavourable soft and hard tissue profile. This paper demonstrates how to manage such patients and shows all the clinical and laboratory stages involved

A double-blind, crossover study of Biotène Oralbalance and BioXtra systems as salivary substitutes in patients with post-radiotherapy xerostomia.

This study assessed the efficacy of the Bioxtra (BX) and Biotène Oralbalance (OB) systems in the treatment of post-radiotherapy xerostomia. In a double-blind, crossover study, 20 patients with post-radiotherapy xerostomia were randomly allocated to receive either OB then BX, or vice versa, each product for 2 weeks, with a 1 week wash-out period in between. Subject-based dry mouth scores derived from 100-mm visual analogue scales were recorded at days 0 and 14 of each 2-week period, together with subjective perception of changes in dry mouth symptoms. Both treatments were effective, resulting in reduction of visual analogue scale scores from day 0-14. Between-groups comparisons identified that BX achieved significantly better improvements compared with OB for the perception of dry mouth and improvements in speech and was also rated as more pleasant to use than OB (P < 0.05). In conclusion, both treatments were effective in alleviating the symptoms of post-radiotherapy xerostomia, although BX achieved superiority in some of the outcomes assessed compared with OB

Hardness measured with traditional Vickers and Martens hardness methods.

OBJECTIVE: To determine the differences, if any, between hardness measured with traditional Vickers and Martens hardness test methods on denture teeth under 2, 10 and 50 N loads. METHOD: Hardness of acrylic resin (VIV), composite resin (ORT) and porcelain (POR) denture tooth materials was measured using a traditional Vickers hardness (HV) method and Martens hardness (HM) method at 2, 10 and 50N test loads. Vickers hardness was also calculated from the force-indentation depth curves (HVfid) that were recorded during Martens hardness. Indentation creep of the three test materials was also determined during Martens hardness testing. RESULTS: HM values were the same irrespective of the test force used. However, HV values were different for the three test forces. ANOVA using Tukey's test of the HM data showed that the hardness of POR was significantly higher than VIV or ORT (P<0.001). Moreover, ORT had a significantly higher hardness than VIV (P<0.001). The statistical analysis of HVfid data showed similar results. ANOVA of the HV data showed the hardness of VIV to be significantly higher than ORT (P<0.001) under 2, 10 and 50 N test load. The HV values for POR under 2 and 10 N test load could not be calculated because of inability to measure the indentation diagonals. Under the 50 N load, the hardness of POR was significantly higher than VIV and ORT. POR had a significantly lower creep value than any other material tested while VIV showed a statistically significantly higher creep than ORT. SIGNIFICANCE: This study confirms that the visco-elastic recovery of the materials has a very significant effect on the outcome of the hardness tests of denture teeth and the Martens hardness test method has obvious advantages when testing dental materials