Influence of eight debridement techniques on three different titanium surfaces: A laboratory study.

OBJECTIVES: Debridement methods may damage implant surfaces. This in vitro study investigated eight debridement protocols across three implant surfaces to assess both biofilm removal and surface alterations. MATERIAL AND METHODS: One hundred sixty commercially pure titanium discs were treated to simulate commercially available titanium implant surfaces-smooth, abraded and abraded and etched. Following inoculation with whole human saliva to create a mixed species biofilm, the surfaces were treated with eight debridement methods currently used for clinical peri-implantitis (n = 10). This included air abrasion using powders of glycine, sodium bicarbonate and calcium carbonate; conventional mechanical methods-piezoelectric scaler, carbon and stainless steel scalers; and a chemical protocol using 40% citric acid. Following treatment, remaining biofilm was analysed using scanning electron microscopy and crystal violet assays. For statistical analysis, ANOVA was applied (p < 0.05). RESULTS: All debridement techniques resulted in greater than 80% reduction in biofilm compared with baseline, irrespective of the surface type. Glycine powder delivered through an air polishing system eliminated the most biofilm. Mechanical instruments were the least effective at eliminating biofilm across all surfaces and caused the greatest surface alterations. Citric acid was comparable with mechanical debridement instruments in terms of biofilm removal efficacy. Titanium surfaces were least affected by air abrasion protocols and most affected by mechanical methods. CONCLUSIONS: Mechanical protocols for non-surgical debridement should be approached with caution. Glycine powder in an air polisher and 40% citric acid application both gave minimal alterations across all implant surfaces, with glycine the superior method in terms of biofilm removal.

Circulating Nucleated Red Blood Cells: An Updated Reference Interval.

CONTEXT.­: Nucleated red blood cells (nRBCs) are not identified in the peripheral blood in healthy individuals beyond the neonatal period. Their presence in children and adults is traditionally considered pathologic. Contemporary hematology analyzers measure nRBCs at very low levels compared to traditional manual morphometric methods. The original launch of the Sysmex XN analyzer in this study's clinical laboratory verified the previously used nRBC reference interval of 0.00 to 0.01 × 106/µL. However, nRBC results from apparently healthy patients were flagged as abnormal (high), subsequently causing patient anxiety and increased subspecialty referrals. OBJECTIVE.­: To determine whether current reference intervals (RIs) for nRBCs were clinically relevant. DESIGN.­: We performed a prospective analysis of 405 300 specimens from nonhospitalized individuals who received a complete blood count. Applying inclusion/exclusion criteria produced a total specimen pool of 66 498. RESULTS.­: Of the 66 498 samples with otherwise normal complete blood count results from healthy, nonhospitalized individuals, 338 showed results outside the previously established RI; 336 of 66 498 (0.5%) had nRBC results greater than 0.01 × 106/µL. Two samples had nRBC values greater than 0.10 ×106/µL. CONCLUSIONS.­: Based on statistical analysis of our results, we concluded that the upper limit of the RI could be updated from 0.01 × 106/µL to 0.10 × 106/µL. Increasing the upper limit of normal for the nRBC RI should decrease patient consternation from an abnormal laboratory value and significantly decrease costs through reducing unnecessary follow up care, and without causing patient harm.

Analysis of the costs and payments of a coordinated stroke center and regional stroke network.

BACKGROUND AND PURPOSE: An earlier study demonstrated significantly improved access, treatment, and outcomes after the implementation of a progressive, comprehensive stroke program at a tertiary care community hospital, Saint Luke's Neuroscience Institute (SLNI). This study evaluated the costs associated with implementing such a program. METHODS: Retrospective analysis of total hospital costs and payments for treating patients with ischemic stroke at SLNI (n=1570) as program enhancement evolved over time (2005, 2007, and 2010) and compared with published national estimates. Analyses were stratified by patient demographic characteristics, patient outcomes, treatments, time, and comorbidities. RESULTS: Controlling for inflation, there was no difference in SLNI total costs between 2005 and either 2007 or 2010, suggesting that while SLNI provided an increased level of services, any additional expenditures were offset by efficiencies. SLNI total costs were slightly lower than published benchmarks. Consistent with previous stroke care cost estimates, the median overall differential between total hospital costs and payments for all ischemic stroke cases was negative. CONCLUSIONS: SLNI total costs remained consistent over time and were slightly lower than previously published estimates, suggesting that a focused, streamlined stroke program can be implemented without a significant economic impact. This finding further demonstrates that providing comprehensive stroke care with improved access and treatment may be financially feasible for other hospitals.

Cost-effectiveness of herpes zoster vaccines in the U.S.: A systematic review.

The purpose of this study was to conduct a systematic review to evaluate the cost-effectiveness evidence of herpes zoster vaccines in the U.S. A systematic literature review was undertaken for U.S. studies focused on the cost-effectiveness of herpes zoster vaccines. Eligibility criteria included studies that evaluated the cost-effectiveness of the recombinant zoster vaccine (RZV) and zoster vaccine live (ZVL) and were published between 2015 and 2021. Article titles and abstracts were reviewed to identify relevant publications. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) criteria for economic evaluations were used to evaluate the studies. Eleven published studies met inclusion and exclusion criteria. Seven studies compared RZV and ZVL. Four studies compared ZVL dosing regimens with or without a no vaccine option. All studies incorporated health system costs. Ten out of eleven (90.9%) studies conducted their analyses from a societal perspective and included indirect costs. For measurements of effectiveness, ten of eleven (90.9%) studies estimated quality-adjusted life years, four (36.4%) used shingles cases averted, two (18.2%) employed deaths prevented, and one (9.1%) measured life years saved. All studies that compared RZV with no vaccine found RZV to be a cost-effective strategy to prevent both shingles and post-herpetic neuralgia. Additionally, these analyses showed that RZV consistently dominated ZVL. Compliance with the second RZV dose was important for full benefit of the vaccine. The studies identified in this systematic review identified well-constructed cost-effectiveness analyses of herpes zoster vaccines in the U.S. RZV was more cost-effective than no vaccine or ZVL. This systematic review supports removal of ZVL from the U.S. market.

Evaluation of multiple implant-bone parameters on stress characteristics in the mandible under traumatic loading conditions.

PURPOSE: The inter-relationships between various implant and bone parameters were evaluated for their influence on the von Mises stress distribution within the mandible using the finite element procedure. The maximum compressive stresses in cancellous and cortical bone were compared to the published stress-strain data to determine bone fracturing status when the maximum (traumatic) loading is applied. MATERIALS AND METHODS: Parameters considered herein include the implant diameter and length. Also considered are Young's modulus of cancellous bone and that of cortical bone, along with its thickness. The implant-bone system was modeled using two-dimensional plane strain elements, 50% osseointegration between implant and cancellous bone was assumed, and linear relationships were assumed between the stress value and Young's modulus of both cancellous and cortical bone at any specific point within the mandible. RESULTS: Implant length was more influential than implant diameter within cancellous bone, whereas implant diameter was more influential in cortical bone. A ranking of all the parameters indicated that the applied masticatory force had a more significant influence on the stress difference, in both cancellous and cortical bone, than all other parameters. Young's modulus of cortical bone and implant length were least influential in cancellous and cortical bone, respectively. Under traumatic loading, cancellous bone fractured for all parameter combinations. When all parameters were set to their average values, the cortical bone did not fracture under traumatic loading. However, it fractured if all the parameters were all set to the minimum values. CONCLUSION: Quantitative evaluation and ranking of the major implant and bone parameters will help provide practical guidelines that are useful for the design and testing of dental implants. The study may also be of interest to dental professionals in evaluating possible implant placement options under various clinical scenarios.

Influence of bone and dental implant parameters on stress distribution in the mandible: a finite element study.

PURPOSE: The complicated relationships between mandibular bone components and dental implants have attracted the attention of structural mechanics researchers as well as dental practitioners. Using the finite element method, the present study evaluated various bone and implant parameters for their influence on the distribution of von Mises stresses within the mandible. MATERIALS AND METHODS: Various parameters were considered, including Young's modulus of cancellous bone, which varies from 1 to 4 GPa, and that of cortical bone, which is between 7 and 20 GPa. Implant length (7, 9, 11, 13, and 15 mm), implant diameter (3.5, 4.0, 4.5, and 5.5 mm), and cortical bone thickness (0.3 to 2.1 mm) were also considered as parameters. Assumptions made in the analysis were: modeling of the complex material and geometric properties of the bone and implant using two-dimensional triangular and quadrilateral plane strain elements, 50% osseointegration between bone and implant, and linear relationships between the stress value and Young's modulus of both cancellous and cortical bone at any specific point. RESULTS: An increase in Young's modulus and a decrease in the cortical bone thickness resulted in elevated stresses within both cancellous and cortical bone. Increases in the implant length led to greater surface contact between the bone and implant, thereby reducing the magnitude of stress. CONCLUSIONS: The applied masticatory force was demonstrated to be the most influential, in terms of differences between minimum and maximum stress values, versus all other parameters. Therefore loading should be considered of vital importance when planning implant placement.

Effectiveness of implant surface debridement using particle beams at differing air pressures.

Because implant surface decontamination is challenging, air powder abrasive systems have been suggested as an alternative debridement method. This in vitro study investigated the effectiveness of different powder formulations and air pressures in cleaning implant surfaces and the extent of surface damage. A validated ink model of implant biofilm was used. Sterile 4.1 × 10 mm Grade 4 titanium implants were coated in a blue indelible ink to form a uniform, visually detectable biofilm-like layer over the implant threads and mounted into a bone replica material with bony defects to approximate peri-implantitis. Air powder abrasive treatments were undertaken using glycine, sodium bicarbonate, or calcium carbonate powder at air pressures of 25, 35, 45, and 55 psi. Digital macro photographs of the threads were stitched to give composite images of the threads, so the amount of ink remaining could be quantified as the residual area and expressed as a percentage. Implant surfaces were also examined with scanning electron microscopy to grade the surface changes. No treatment cleaned all the surface of the threads. The powders were ranked in order of decreasing effectiveness and decreasing surface change into the same sequence of calcium carbonate followed by sodium bicarbonate followed by glycine. Higher air pressure improved cleaning and increased surface change, with a plateau effect evident. All powders caused some level of surface alteration, with rounding of surface projections most evident. With air powder abrasive systems, there is a trade-off between cleaning efficacy and surface damage. Using this laboratory model, sodium bicarbonate and calcium carbonate powders were the most effective for surface cleaning when used at air pressures as low as 25 psi.

Multistate Health Plans: Agents for Competition or Consolidation?

We discuss and evaluate the Multi-State Plan (MSP) Program, a provision of the Affordable Care Act that has not been the subject of much debate as yet. The MSP Program provides the Office of Personnel Management with new authority to negotiate and implement multistate insurance plans on all health insurance exchanges within the United States. We raise the concern that the MSP Program may lead to further consolidation of the health insurance industry despite the program's stated goal of increasing competition by means of health insurance exchanges. The MSP Program arguably gives a competitive advantage to large insurers, which already dominate health insurance markets. We also contend that the MSP Program's failure to produce increased competition may motivate a new effort for a public health insurance option.

A comparison of two methods of enhancing implant primary stability.

BACKGROUND: Surgical technique and implant design have an effect on the primary stability of oral implants, which in turn increases resistance to implant micromotion during healing. PURPOSE: This study was designed to compare the parameters associated with implant insertion using two different methods of enhancing implant primary stability and to identify any relationship between these parameters and changes in the stability of implants during the initial 6-month healing period following implant insertion. A comparison was made between two methods of enhancing primary implant stability: method 1, standard Brånemark System implants (Nobel Biocare AB, Gothenburg, Sweden) inserted with a technique designed to enhance primary stability, and method 2: Brånemark Mk IV implants (Nobel Biocare AB) inserted according to the manufacturer's instructions. MATERIALS AND METHODS: Thirteen patients were selected for inclusion in the study. A total of 42 implants were placed. Insertion torque data were recorded, and bone quality at the implant site was assessed at implant insertion. Resonance frequency analysis measurements were taken at implant insertion as well as at second-stage surgery 6 months later. RESULTS: A statistically significant difference was recorded between the mean maximum insertion torque for type 4 bone and bone types 2 and 3. No significant difference was recorded between bone types 2 and 3. A significantly lower resonance frequency value was seen for standard implants placed into type 4 bone (p < .05). Across all implant types a significant difference in the energy required when inserting implants into type 4 bone and bone types 2 and 3 was seen. A significantly lower mean energy requirement was seen between the Mk IV implants placed into type 4 bone and the other combinations of implant types and bone. CONCLUSIONS: Within the limitations of this study, the results agree with the manufacturer's claim that when compared with standard implants, the design of the Mk IV implant increases implant primary stability with a reduction in the energy imparted into the bone at the implant site.

Resonance frequency measurement of implant stability in vivo on implants with a sandblasted and acid-etched surface.

PURPOSE: To determine the changes in stability as a reflection of early healing around single-stage, roughened-surface implants in humans utilizing resonance frequency analysis (RFA). RFA makes use of a transducer, attached to an implant, which is excited over a range of sound frequencies with subsequent response analysis. MATERIALS AND METHODS: Twenty patients had 1 to 4 implants placed in the posterior maxilla or mandible. Bone type was classified into 1 of 4 groups according to the Lekholm and Zarb index (1985). RFA was used for direct measurement of implant stability on the day of implant placement and consecutively once per week for 6 weeks and at weeks 8 and 10. RESULTS: Twenty-seven ITI SLA implants placed in the premolar and molar regions of the maxilla and mandible were evaluated. Early failure occurred with 1 implant related to parafunction. The remaining 26 implants were distributed as follows: 29.6% in Type 1 bone, 37% in Type 2 or 3 bone, and 33.3% in Type 4 bone. The lowest mean stability measurement was at 3 weeks for all bone types. The percentage decrease in stability from baseline to 3 weeks was highest for Type 4 bone (8.6%), as was the percentage increase in stability from 3 to 10 weeks (26.9%). A Bonferroni adjusted Student t test comparison of bone groups at each time point revealed highly significant differences between implant stability in Types 1 and 4 bone at 3 weeks (P = .004) and a moderately significant difference between Types 2, 3, and 4 bone (P = .08) at 3 weeks. Implant stability did not change significantly during the 10-week period in Type 1 bone (P > .10). With the same test, by 5 weeks, no bone groups showed any difference in implant RFA measurements (P = 1.0). DISCUSSION: This study demonstrated the lowest values for implant stability at 3 weeks after placement for all bone types. This effect was statistically significant and most pronounced in Type 4 bone. CONCLUSION: There was no significant difference in the pattern of stability changes among different bone types after 5 weeks of healing.

An evaluation of the reasons why patients attend a hospital Emergency Department.

This survey evaluates the attendance patterns of people who responded to a two part questionnaire (before and after treatment) regarding the reasons they had presented at a hospital Emergency Department co located with an Urgent Care Centre. A total 485 people responded before treatment and 163 people responded after completing treatment. People have deep rooted convictions that the 'hospital' is the best place to be seen for the treatment of their accident or perceived emergency, together with a considerable loyalty and emotional attachment to it. Few people knew that Urgent Care facilities existed within the Emergency Department and fewer what they were for. Some were frustrated at the apparent speed of access to care by those with apparently trivial problems, not understanding that they were accessing a different service. On the whole people who attended were happy with the advice and treatment they received.

Immediate/Early function of Neoss implants placed in maxillas and posterior mandibles: an 18-month prospective case series study.

BACKGROUND: An increasing number of studies show that immediate/early function of dental implants can be as successful as two-stage procedures. However, the results may not be universal for all implant types and it is important that new implants are tested for this treatment modality. PURPOSE: The aim was to evaluate an immediate/early function protocol in the maxilla and in the posterior mandible using Neoss implants (Neoss Ltd., Harrogate, UK). MATERIALS AND METHODS: A total of 21 patients were provided with 69 Neoss implants (4 mm in diameter and 9-15 mm in length) and a provisional bridge within 7 days (mean 4.6 days). Sixteen implants were placed in immediate extraction sites where seven were treated with autologous bone grafts (n = 6) or bone grafts + resorbable membrane (n = 1). A final fixed prosthesis was made 3 to 6 months later. The patients were followed-up with clinical examinations for 18 months. In addition, the implants were monitored with resonance frequency analysis (RFA) measurements at surgery and after 1, 2, and 6 months. Intraoral radiographs were taken after surgery and after 1, 6, and 18 months. RESULTS: One implant in an extraction site in the maxilla failed after 1 month, giving a survival rate of 98.5% after 18 months. The mean marginal bone loss was 0.7 mm (SD 0.7) after 18 months. RFA showed a mean implant stability quotient (ISQ) value of 68.1 (SD 8.8) at surgery, which increased to 73.7 (SD 5.7) after 6 months. The primary stability for maxillary and mandibular implants was similar, although mandibular implants showed slightly higher values with time. Implants in extraction sockets showed a lower initial stability than in healed sites, ISQ 65.8 (SD 7.5), which increased to ISQ 67.5 (SD 6.9) after 6 months. The failed implant showed an ISQ of 74 at placement, which decreased to 42 1 month after surgery. CONCLUSION: Within the limitations of the present study, it is concluded that immediate/early function with Neoss implants is a reliable method with an implant survival rate comparable to that of the traditional two-stage protocol.

Step-wise analysis of the dental implant insertion process using the finite element technique.

OBJECTIVES: Using the finite element method (FEM), the insertion process of a dental implant into a section of the human mandible is analysed. The ultimate aim of this article is to advance the use of an innovative engineering approach in dental practices, especially in the process of dental implantation. MATERIAL AND METHODS: The FEM and analysis techniques are used to replicate and evaluate the stress profile created within the mandible during the implantation process. RESULTS: The von Mises stress profiles in both cancellous and cortical bone are examined during implant insertion. The applied torque and the insertion stage are found to strongly influence the resulting stress profile within the surrounding jawbone. CONCLUSIONS: Through the combination of both dental and engineering expertise, a simplified and efficient modelling technique is developed. This improves the understanding of the biomechanical reaction that the jawbone exhibits due to the insertion of implant. The current research is a pilot study using the FEM to model and simulate the dental implantation process. The assumptions made in the modelling and simulation process are: (1) the implantation process is simulated as a step-wise process instead of a continuous process; (2) the implant is parallel threaded and the implant does not rotate during insertion into the jawbone. Although the modelling and simulation techniques had to be simplified, a significant amount of information is gained that helps lay a good foundation for future research. Recommendations for future studies include the variation of the torque applied during the implantation process and upgrading the software capabilities to simulate the full dynamical process of implantation.

Influence of implant taper on the primary and secondary stability of osseointegrated titanium implants.

OBJECTIVES: The study presented was designed to analyse the mechanical performance and the primary and secondary stability characteristics of endosseous titanium implants with 1 degree (EXP1) and 2 degrees (EXP2) of taper when compared with the standard Brånemark design (Nobel Biocare AB, Gothenburg, Sweden). MATERIALS AND METHODS: One pair of 10 mm EXP1 and control implants were placed in the femoral condyles of six rabbits. Paired 6 mm EXP1 and control implants and 6 mm EXP2 and control implants were placed in the tibial metaphysis. The control implants used were 4 mm diameter standard Brånemark implants, the same length as the test implants. At placement, insertion torque (IT) and resonance frequency analysis (RFA) measurements were performed. Six weeks postoperatively when the animals were killed, RFA and removal torque (RT) measurements were made. RESULTS: At placement, significantly higher IT was needed to insert the EXP implants compared with the controls. RFA values were significantly higher for EXP1 implants placed in the tibia but not in the femur. In pooling data from the femur and tibia there was a significant difference. The EXP2 implants failed to insert fully and demonstrated a lower RFA value than may have been expected due to the exposed threads, although this difference was not statistically significant. CONCLUSIONS: The results from the present study showed that 1 degrees of taper results in a better primary stability compared with the standard Brånemark design. There was no evidence that the tapered design caused negative bone tissue reactions. All the implants gained in stability during the healing period.

Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading. Successful vs. failing implants.

OBJECTIVES: The objective of this study was to analyze the development of implant stability by repeated resonance frequency analysis (RFA) measurements during 1 year in 23 patients treated according to an immediate/early-loading protocol. The objective was also to evaluate the possible differences between failing and successful implants. MATERIAL AND METHODS: Eighty-one Brånemark System implants were placed in 23 patients for immediate/early-occlusal loading in all jaw regions. Thirty of the implants were placed in extraction sockets and 62 were subjected to GBR procedures. Apart from clinical and radiographic examinations, the patients were followed with RFA at placement, prosthesis connection and after 1-3, 6 and 12 months. Statistical analyses were carried out to study the possible differences between implants that failed during the study period and implants that remained successful. RESULTS: Nine implants failed (11.2%) during the 1 year of loading. RFA showed a distinct different pattern between the implants that remained stable and the implants that were lost. The implants that failed during the course of the study showed a significantly lower stability already after 1 month. CONCLUSION: Within the limitations of this study, it is concluded that failing implants show a continuous decrease of stability until failure. Low RFA levels after 1 and 2 months seem to indicate an increased risk for future failure. This information may be used to avoid implant failure in the future by unloading implants with decreasing degree of stability with time as diagnosed with the RFA technique.