Effect of software version and parameter settings on the marginal and internal adaptation of crowns fabricated with the CAD/CAM system

Objective

This study investigated the marginal and internal adaptation of individual dental crowns fabricated using a CAD/CAM system (Sirona’s BlueCam), also evaluating the effect of the software version used, and the specific parameter settings in the adaptation of crowns.

Material and Methods

Forty digital impressions of a master model previously prepared were acquired using an intraoral scanner and divided into four groups based on the software version and on the spacer settings used. The versions 3.8 and 4.2 of the software were used, and the spacer parameter was set at either 40 μm or 80 μm. The marginal and internal fit of the crowns were measured using the replica technique, which uses a low viscosity silicone material that simulates the thickness of the cement layer. The data were analyzed using a Friedman two-way analysis of variance (ANOVA) and paired t-tests with significance level set at p<0.05.

Results

The two-way ANOVA analysis showed the software version (p<0.05) and the spacer parameter (p<0.05) significantly affected the crown adaptation. The crowns designed with the version 4.2 of the software showed a better fit than those designed with the version 3.8, particularly in the axial wall and in the inner margin. The spacer parameter was more accurately represented in the version 4.2 of the software than in the version 3.8. In addition, the use of the version 4.2 of the software combined with the spacer parameter set at 80 μm showed the least variation. On the other hand, the outer margin was not affected by the variables.

Conclusion

Compared to the version 3.8 of the software, the version 4.2 can be recommended for the fabrication of well-fitting crown restorations, and for the appropriate regulation of the spacer parameter.     

Differential expression of immunologic proteins in gingiva after socket preservation in mini pigs

During healing following tooth extraction, inflammation and the immune response within the extraction socket are related to bone resorption.

Objective

: We sought to identify how the alloplastic material used for socket preservation affects the immune responses and osteoclastic activity within extraction sockets.

Material and Methods

: Using a porcine model, we extracted teeth and grafted biphasic calcium phosphate into the extraction sockets. We then performed a peptide analysis with samples of gingival tissue from adjacent to the sockets and compared the extraction only (EO) and extraction with socket preservation (SP) groups. We also used real-time polymerase chain reaction (PCR) to evaluate the expression level of immunoglobulins, chemokines and other factors related to osteoclastogenesis. Differences between the groups were analyzed for statistical significance using paired t tests.

Results

: Levels of IgM, IgG and IGL expression were higher in the EO group than in the SP group 1 week post-extraction, as were the levels of CCL3, CCL5, CXCL2, IFN-γ and TNF-α expression (p<0.05). In addition, receptor activator of nuclear factor kappa-B ligand (RANKL) was also significantly upregulated in the EO group (p<0.05), as were IL-1β, IL-6 and IL-8 (p<0.05).

Conclusions

: These results suggest that the beneficial effect of socket preservation can be explained by suppression of immune responses and inflammation.     

Effect of a multi-layer infection control barrier on the micro-hardness of a composite resin

Objective

The aim of this study was to evaluate the effect of multiple layers of an infection control barrier on the micro-hardness of a composite resin.

Material and Methods

One, two, four, and eight layers of an infection control barrier were used to cover the light guides of a high-power light emitting diode (LED) light curing unit (LCU) and a low-power halogen LCU. The composite specimens were photopolymerized with the LCUs and the barriers, and the micro-hardness of the upper and lower surfaces was measured (n=10). The hardness ratio was calculated by dividing the bottom surface hardness of the experimental groups by the irradiated surface hardness of the control groups. The data was analyzed by two-way ANOVA and Tukey''s HSD test.

Results

The micro-hardness of the composite specimens photopolymerized with the LED LCU decreased significantly in the four- and eight-layer groups of the upper surface and in the two-, four-, and eight-layer groups of the lower surface. The hardness ratio of the composite specimens was <80% in the eight-layer group. The micro-hardness of the composite specimens photopolymerized with the halogen LCU decreased significantly in the eight-layer group of the upper surface and in the two-, four-, and eight-layer groups of the lower surface. However, the hardness ratios of all the composite specimens photopolymerized with barriers were <80%.

Conclusions

The two-layer infection control barrier could be used on high-power LCUs without decreasing the surface hardness of the composite resin. However, when using an infection control barrier on the low-power LCUs, attention should be paid so as not to sacrifice the polymerization efficiency.     

The economics of inpatient on‐demand treatment for haemophilia with high‐responding inhibitors: a US retrospective data analysis

Summary. Inpatient costs comprise >50% of annual healthcare costs for haemophilia patients with inhibitors but no reports exist on inpatient resource use and costs at a US national level. To quantify inpatient resource use and costs for on‐demand treatment of bleeds of US haemophilia patients with inhibitors and compare costs and treatment duration between Factor VIII bypassing agents (BAs). Stays with haemophilia A from 2003–2008 were identified from inpatient billing records. Presence of inhibitors was inferred through use of BA; recombinant activated Factor VII and plasma‐derived activated prothrombin complex concentrate. Duration and number of infusions of BA, length of stay, use of opioid‐containing analgesics and costs were assessed and compared. Among 1322 stays mean BA treatment duration was 4.6 days with 4.9 infusions, 6.1 nights spent in hospital, and 58% administered opioid‐containing analgesics. In unadjusted analyses there were significant differences in the above mentioned outcomes by BA use, reflecting underlying differences between the two patient populations. Average inpatient costs were $82 911. In adjusted analyses, African‐American race, greater disease severity, hospital region outside the southern US and older age (cost model only) were significant predictors of longer BA treatment duration and higher costs. The economic burden of inpatient on‐demand treatment of haemophilia with inhibitors is substantial and is associated with lengthy stays, high costs and inadequate pain relief. Availability of more effective BAs could reduce the need for re‐treatment, reducing treatment costs and other medical costs, while improving health related quality of life.     

某医学中心药师对民众用药安全教育的经验交流

为推广正确用药知识,提升民众用药安全核心能力,使药品发挥治疗效果并避免药品使用不当产生不良后果,台湾地区某一大型综合医院药剂科药师通过成立"正确用药教育资源中心",联合各级药学会、学校、社区、公共平台等资源,让医院药师走出医院,走进校园、社区、公共场所等,借助活动、宣传、科普教育等方式,2014-2015年共举办114场,参与人数达到14 140人次,活动满意度达98.5%。藉此模式除提升民众正确用药的核心能力,同时可建构用药安全网,并充分发挥医院药师的工作价值。