Effects of simulated long-term exposure to bottled, neutral pH electrolyzed oxidizing water on the properties of denture base resins.

STATEMENT OF PROBLEM: Denture stomatitis can pose serious health risks, especially to older people. Chemical denture cleaning agents must be effective, yet not adversely affect the longevity of removable dentures. Ready-to-use (RTU) neutral pH electrolyzed oxidizing water (EOW) is an effective biocide against Candida albicans biofilms on denture resins, but the effects of daily disinfection with EOW on the physical and mechanical properties of resins have not been established. PURPOSE: The purpose of this in vitro study was to investigate the effects of simulated long-term exposure to RTU EOW on the color, surface characteristics, and flexural strength of denture base resins. MATERIAL AND METHODS: Heat-polymerized (HP), 3D printed (3D) and computer-aided design and computer-aided manufacture (CAD-CAM)-milled (CC) denture resin specimens (square: 20×20×3.3 mm; beam: 64×10×3.3 mm) were immersed in tap water (TW), RTU EOW (Neutral Anolyte ANK; Envirolyte; EOW), or a commercial denture cleaning tablet solution (Polident 3-Minute; Glaxo SmithKline; PD), mimicking a 5-minute once daily disinfection routine performed up to 3.0 years. Color and surface roughness were recorded (n=3, squares), and changes in color (∆E00) and surface roughness (∆Ra) were calculated. Flexural strength (n=12, beams) and surface hardness (n=18, beams) were measured with a universal testing machine. The fractured surfaces of specimens were examined by scanning electron microscopy and energy dispersive spectroscopy. Data were assessed by performing the Shapiro-Wilk or D'Agostino and Pearson normality tests. Two-way ANOVA or the Kruskal-Wallis test with a post hoc Tukey HSD or Dunn multiple comparisons (α=.05) was used for statistical analyses. RESULTS: No significant changes were found in either color or surface roughness for HP, 3D, and CC resins after 1.5-year and 3.0-year immersion in any of the agents (P>.05). The surface hardness of 3D resins reduced by 14% with TW and by 23% with EOW and PD at 3.0 years. The flexural strengths of all 3 resins were unaffected by 3.0-year immersion (P>.05). CONCLUSIONS: Simulated long-term immersion disinfection with RTU neutral pH EOW did not adversely affect the physical and mechanical properties of HP or CC denture resins.

Effectiveness of gold nanoparticles in prevention and treatment of oral mucositis in animal models: a systematic review.

BACKGROUND: Oral mucositis remains a significant complication during cancer therapy with no effective treatment. Gold nanoparticles offer anti-inflammatory, antioxidant properties with low toxicity. This study systematically reviews the literature assessing gold nanoparticles in the management of oral mucositis in animal models. METHODS: A literature search was undertaken using MEDLINE, Embase, PubMed, and Web of Science databases, using the format for Systematic Review Centre for Laboratory Animal Experimentation. Prior to the review, the protocol was registered in the systematic review register, PROSPERO (registration no. CRD42021272169). Outcome measures included ulceration, histopathological scores, inflammatory mediators, microbial growth, and pain. Study quality was analysed by SYRCLE risk-of-bias tool. RESULTS: Only one study met the inclusion criteria, documenting reduction in ulceration, inflammatory, and oxidative biomarkers. Exposure to AuNPs prevented inflammatory response induced by 5-fluorouracil in oral mucosa of hamsters. However, a high risk of bias necessitates further research. CONCLUSION: This review identifies a potential therapeutic strategy for prevention and management of oral mucositis. It also provides future direction for gold nanoparticle research in oral mucositis; however, there is lack of sufficient evidence to derive any conclusion. Research with standardized parameters including nanoparticle size, capping agent, surface charge, and appropriate oral mucositis animal models will establish risk-benefit balance and margin of safety for therapeutic use of gold nanoparticles for oral mucositis.

Electrolysed oxidising water as a multi-purpose biocide in dental healthcare-A scoping review.

OBJECTIVES: The objective of this scoping review was to map evidence of electrolysed oxidising water (EOW) as a biocide for dental applications of relevance to older people and identify research gaps. BACKGROUND: EOW is an emerging, "green," and cost-effective biocide. There are no reviews on the landscape of EOW research as either an antiseptic or disinfectant in dental healthcare or its suitability for the oral healthcare of older people. MATERIALS AND METHODS: The review follows the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines. Database searches (Google Scholar, PubMed, Web of Science, Ovid, Scopus and Science Direct) were undertaken using MESH terms and Boolean operators with no date restrictions, to identify full-text, original reports published in English-language peer-reviewed journals. RESULTS: The search yielded 114 papers that met the inclusion/exclusion criteria. Dental applications of EOW include its use as an endodontic irrigant (39%); mouth rinse/surgical irrigant (21%); disinfectant for dental unit water lines (19%) and dental biomaterials (17%); and for antimicrobial efficacy, effects on oral tissues and on dental material properties. Most studies (83%) evaluated a single EOW formulation (acidic, moderately acidic or neutral) that was either generated at 'point-of-use' (POU; 72%), bottled ('ready-to-use', RTU; 24%) or from unspecified (3%) sources. Six reports evaluated storage-related parameters and 25 evaluated clinical applications; 89 were in vitro studies and one investigated the cost-effectiveness of POU EOW. CONCLUSIONS: Neutral-pH, EOW is effective as an antimicrobial agent without deleterious effects on oral tissues. However, research on the impact of storage conditions, anti-Candida biofilm efficacy and mechanism of action against yeasts, long-term effects on denture materials and cost-effectiveness is required to establish the suitability of EOW as a multipurpose biocide for dental healthcare, including infection-control requirements relating to older people.

Bone Cement Waste in Total Knee Arthroplasty: A Preliminary Study of Scope and Cost.

Background: Medical waste is both costly and detrimental to the environment, and operating room waste represents a substantial portion of this. To the authors' knowledge, bone cement waste in total knee arthroplasty (TKA) has not previously been studied. The vast majority of TKA are cemented, and the volume of TKA is forecast to increase. Given this, we studied the waste resulting from the routine use of 2 40-gram bags of polymethyl methacrylate (PMMA) powder during cementing in primary TKA. Methods: We first studied the yield of commercially available plain and gentamicin medium-viscosity bone cement powder and calculated the cost/gram of product. We then collected the PMMA remaining after primary TKA to determine the average amount of waste, its cost, and possible correlations with patient and implant metrics that could improve efficiency and reduce waste of PMMA. Results: Overall, PMMA waste averaged 59% per TKA, at a median cost of $129 per case. Cost of waste was greater when gentamicin cement was used, as its cost was 2.5X that of plain cement. Implant sizes and surface area ranges were identified that could reliably allow the use of a single 40-gram package of powder, potentially reducing PMMA waste. Conclusions: While it is acknowledged that zero-waste cementing is not practical, any reduction in waste that does not compromise either the flow of surgery or the adequacy of fixation would be beneficial. Reevaluation of PMMA techniques could reduce waste, resulting in both cost savings and improved sustainability in arthroplasty.

Registry Data Show Complication Rates and Cost in Revision Hip Arthroplasty.

BACKGROUND: Revision total hip arthroplaty (rTHA) places a burden on patients, surgeons, and health care systems because outcomes and costs are less predictable than primary THA. The purpose of this study was to define indications and treatments for rTHA, quantify risk for readmissions, and evaluate the economic impacts of rTHA in a hospital system. METHODS: The arthroplasty database of a hospital system was queried to generate a retrospective cohort of 793 rTHA procedures, performed on 518 patients, from 2017 to 2019 at 27 hospitals. Surgeons performed chart reviews to classify indication and revision procedure. Demographics, lengths of stay, discharge dispositions, and readmission data were collected. Analyses of direct costs were performed and categorized by revision type. RESULTS: Totally, 46.3% of patients presented for infection. Patients presenting for infection were 5.6 times more likely to have repeat rTHA than aseptic patients. Septic cases (4.3 days) had longer length of stay than aseptic ones (2.4) (P < .0001). However, 31% of patients discharged to a skilled nursing facility. Direct costs were greatest for a two-stage exchange ($37,642) and lowest for liner revision ($8,979). Septic revisions ($17,696) cost more than aseptic revisions ($11,204) (P < .0001). The 90-day readmission rate was 21.8%. Septic revisions had more readmissions (13.5%) than aseptic revisions (8.3%). CONCLUSIONS: Hip revisions, especially for infection, have an increased risk profile and create a major economic impact on hospital systems. Surgeons may use these data to counsel patients on risks of rTHA and advocate for improved reimbursement for the care of revision patients.

Enhancing the student learning experience: Co-teaching biochemistry and clinical sciences within the dental curriculum.

Basic knowledge of biochemistry underpins oral and dental care. Undergraduate dental students do not always engage well with basic science teaching due to not appreciating its clinical relevance. Co-teaching provides one approach to overcome students' disengagement and involves two lecturers, with complementary expertise, presenting the curriculum together. This study investigated student experiences and engagement using co-teaching to integrate biochemistry with clinical sciences in the students' second-year dental curriculum. Two successive second year dental student cohorts were co-taught. Content was delivered by a biochemist and an oral biologist, either online (during the 2020 COVID lockdown) or in-person (2021). Each cohort was surveyed at the end of the teaching module using an online questionnaire containing both interval scale and free-text questions. Responses were received from 39 (42%) and 64 (85%) of students in 2020 and 2021, respectively. Students from both cohorts preferred the co-teaching approach with a mean of 8.74 on a 10-point interval scale. In 2020 and 2021, 77% and 76% of participants, respectively, preferred a combined biochemistry and clinical dentistry delivery, either in-person (37%), via Zoom (19%) or via video recording (14%). Thematic analysis of responses revealed students experienced enhanced engagement when co-taught and they attributed this to integration of the curriculum making the content more relevant and stimulating. Students preferred co-teaching to individual subjects being taught by a single teacher. Co-teaching established the relevance of theoretical biochemistry to clinical dental sciences and enhanced the students' learning experience.

The Economic Impact of Lower Extremity Periprosthetic Fractures in a Large Hospital System.

BACKGROUND: Periprosthetic fractures (PPFs) place a burden on hospital systems. They occur in older patients with medical comorbidities, as unplanned events requiring technically complex surgeries with expensive implants. The purpose of this study was to describe this patient population and evaluate the economic impact of PPFs on a hospital system. METHODS: We conducted a retrospective study of PPFs of the hip and knee between 2018 and 2019. Demographics, length of stay (LOS), and discharge disposition were collected. We performed chart and radiographic reviews to determine the fracture classification and type of treatment performed. An analysis of direct inpatient costs was performed and categorized by a fracture type. RESULTS: We identified 213 periprosthetic hip and 151 periprosthetic knee fractures. The mean age of hip patients was 77 years, and 71% were female. The average surgery time was 194 minutes, LOS was 5.01 days, and 71% were discharged to a skilled nursing facility (SNF). The mean age of knee patients was 76 years, and 79% were female. The average surgery time was 174 minutes, LOS was 5.12 days, and 70% were discharged to a SNF. The median direct cost of hip fractures was $17,108, with Vancouver B2 and B3 costing significantly more at $19,987 and $23,935, respectively (P value <.0001). The median direct cost of knee fractures was $13,713. Type 3 distal femur fractures cost significantly more at $37,445 (P value <.0001). CONCLUSION: PPFs create a significant economic impact on hospital systems. We stratified the costs of treatment based on the fracture type. Significantly higher costs are associated with injuries requiring revision implants.

Alkaline Tolerance and Biofilm Formation of Root Canal Isolates of Enterococcus faecalis: An In Vitro Study.

INTRODUCTION: The aim of this study was to compare the effects of glucose and glycerol (provided as principal fermentable supplements) on alkaline tolerance and biofilm-forming capabilities of root canal-derived strains of Enterococcus faecalis and those from other environments. METHODS: The planktonic growth kinetics and the biofilm-forming capabilities of E. faecalis isolates (identified by 16S ribosomal DNA sequencing) were compared when supplied with glucose and glycerol at pH levels of 8 and 11 in a microtiter plate. The metabolic activity of the biofilms plate that formed at a neutral pH level (supplied with either glucose or glycerol) was measured after subsequent adjustment to a pH level of 11. RESULTS: Ten isolates (7 from root canals and 3 from other sources) were examined. The lag phase and the doubling time increased under elevated alkalinity irrespective of either the fermentable supplement (glucose or glycerol) or the origin of the isolate. Biofilm formation and metabolic activity varied among strains, but neither was related to the source of isolation. In general, biofilm formation was enhanced when grown in glucose compared with glycerol and at a pH of 8 compared with a pH of 11 (irrespective of the fermentable supplement). The provision of glycerol did not increase either the planktonic growth rate or biofilm development compared with glucose but significantly increased the metabolic activity of biofilms, especially at a pH of 11 compared with a pH of 8. CONCLUSIONS: In the nutrient-deprived environment of a necrotic or root-filled root canal, glycerol may be an alternative energy source that can promote increased metabolic activity of E. faecalis under alkaline treatment conditions.

Can a Reduction in Revision Rates Make Robotic Total Knee Arthroplasty Cost Neutral With Manual Total Knee Arthroplasty at Ten-Year Follow-Up? An Episode Cost Analysis.

BACKGROUND: Advocates of robotic total knee arthroplasty (RTKA) suggest that its greater cost may be recaptured through a reduction in revision rates. We sought to determine what reduction in revision TKA would be required for RTKA to become cost neutral with manual TKA (MTKA). METHODS: Episode costs were determined for 2392 RTKAs and 2392 MTKAs. Mean total cost of revision TKA in our health system was identified. Episode cost difference of the RTKA and MTKA cohorts was divided by the mean cost of revision TKA to estimate the reduction in revisions required to make RTKA cost neutral with MTKA. The National Joint Registry was consulted to determine the cumulative revision rate for the implant used in this study. RESULTS: Episode cost for the RTKA cohort was $5.7M greater than MTKA. Mean acute stay cost for revision TKA was $20,972, but post-acute costs were not available. If post-acute costs for revision TKA are conservatively estimated at 50% of episode cost (ie, episode cost = $41,944), 131 revision TKAs would need to be prevented in the RTKA cohort to make it cost neutral with MTKA. The National Joint Registry cumulative revision rate for this implant is 3.37% at 10 years, thus only 81 revisions would be expected per cohort. CONCLUSION: Our data suggest that it is not possible for RTKA to achieve cost parity with MTKA through a reduction in revision rate alone. Future price reductions may make the cost comparison more favorable. In addition, demonstration of improved patient outcomes would undeniably add value to RTKA and change the analysis.

Robotic Versus Manual Total Knee Arthroplasty in High Volume Surgeons: A Comparison of Cost and Quality Metrics.

BACKGROUND: Robotic-assisted total knee arthroplasty (RTKA) was introduced to improve surgical accuracy and patient outcomes. However, RTKA may also increase operating time and add cost to TKA. This study sought to compare the differences in cost and quality measures between manual TKA (MTKA) and RTKA METHODS: All MTKAs and RTKAs performed between January 1, 2017 and December 31, 2019, by 6 high volume surgeons in each cohort, were retrospectively reviewed. Cohorts were propensity score matched. Operative time, length of stay (LOS), total direct cost, 90-day complications, utilization of postacute services, and 30-day readmissions were studied. RESULTS: After one-to-one matching, 2392 MTKAs and 2392 RTKAs were studied. In-room/out-of-room operating time was longer for RTKA (139 minutes) than for MTKA (107 minutes) P < .0001, as was procedure time (RTKA 78 minutes; MTKA 70 minutes), P < .0001. Median LOS was equal for MTKA and RTKA (33 hours). Total cost per case was greater for RTKA ($11,615) than MTKA ($8674), P < .0001. Home health care was utilized more frequently after RTKA (38%) than MTKA (29%), P < .0001. There was no significant difference in 90-day complication rates. Thirty-day readmissions occurred more often after MTKA (4.9%) than RTKA (1.2%), P < .0001. CONCLUSION: RTKA was a longer and costlier procedure than MTKA for experienced surgeons, without clinically significant differences in LOS or complications. Home health care was utilized more often after RTKA, but fewer readmissions occurred after RTKA. Longer term follow-up and functional outcome studies are required to determine if the greater cost of RTKA is offset by lower revision rates and/or improved functional results.

Streptococcus salivarius Isolates of Varying Acid Tolerance Exhibit F1F0-ATPase Conservation.

Genes encoding the subunits of the membrane-bound F1F0-ATPase (responsible for exporting protons from the cytoplasm and contributing to acid tolerance) were sequenced for 24 non-mutans streptococci isolated from carious lesions. Isolates, mostly Streptococcus salivarius, displayed a continuum of acid tolerance thresholds ranging from pH 4.55 to 3.39, but amino acid alignments of F1F0-ATPase subunits revealed few non-synonymous substitutions and these were unrelated to acid tolerance. Thus, the F1F0-ATPase is highly-conserved among S. salivarius isolates despite varying acid tolerance thresholds, supporting the contention that acid tolerance is determined by the level of gene/protein expression rather than variation in molecular structure.

Formulation of a Semisolid Emulsion Containing Leptospermum scoparium Essential Oil and Evaluation of In Vitro Antimicrobial and Antibiofilm Efficacy.

Manuka oil, an essential oil derived from the Leptospermum scoparium, has been traditionally used for wound care and as a topical antibacterial, antifungal, and anti-inflammatory. However, the essential oil is not well retained at mucosal sites, such as the oral cavity, where the benefits of the aforementioned properties could be utilized toward the treatment of persistent biofilms. Within this study, L. scoparium essential oil was incorporated into a semisolid emulsion for improved delivery. The safety profile of L. scoparium essential oil on human gingival fibroblasts was determined via cell viability, cytotoxicity, and caspase activation. The minimal bactericidal concentration of L. scoparium essential oil was determined, and the emulsion's antibiofilm effects visualized using confocal laser scanning microscopy. L. scoparium essential oil demonstrated a lower IC50 (0.02% at 48 h) when compared to the clinical control chlorhexidine (0.002% at 48 h) and displayed lower cumulative cytotoxicity. Higher concentrations of L. scoparium essential oil (≥ 0.1%) at 6 h resulted in higher caspase 3/7 activation, suggesting an apoptotic pathway of cell death. A minimal bactericidal concentration of 0.1% w/w was observed for 6 oral bacteria and 0.01% w/v for Porphyromonas gingivalis. Textural and rheometric analysis indicated increased stability of emulsion with a 1 : 3 ratio of L. scoparium essential oil: Oryza sativa carrier oil. The optimized 5% w/w L. scoparium essential oil emulsion showed increased bactericidal penetrative effects on Streptococci gordonii biofilms compared to oil alone and to chlorhexidine controls. This study has demonstrated the safety, formulation, and antimicrobial activity of L. scoparium essential oil emulsion for potential antibacterial applications at mucosal sites.

AgNP/Alginate Nanocomposite hydrogel for antimicrobial and antibiofilm applications.

The synthesis and specific surface functionalization of antimicrobial silver nanoparticles (AgNPs) and their incorporation into an alginate hydrogel is described. Divalent cation-mediated ionic crosslinking was used to disperse the AgNPs throughout the gel, made possible by -COO- cross-linking sites provided by the surface-enhanced nanoparticles, inspired by the classic egg-box model crosslinking of calcium alginate. An AgNP concentration, 10-20 µg g-1 increased hygrogel elasticity, viscosity, and shear resistance by 45, 30, and 31% respectively. Cryo-TEM revealed evenly distributed AgNP assemblies of discrete AgNPs throughout the gel matrices. FTIR-ATR indicated AgNPs were involved in alginate carboxylate-Ca2+-COO-AgNP crossbridging, which was not achieved through mixing of AgNPs into preformed gels. Live/dead fluorometric assays determined a minimal bactericidal concentration of 25 µg g-1 Ag for 6 microorganisms. Anti-biofilm assays showed species-dependent cell death of 44 -61%, with limited silver ion release of 0.41% and 1.1% after 7 days for Gram positive and negative bacteria, respectively.

Extremes of body mass index have significant impact on complications, readmissions, and utilization of post-acute services after primary total hip arthroplasty.

AIMS: High body mass index (BMI) is associated with increased rates of complications in primary total hip arthroplasty (THA), but less is known about its impact on cost. The effects of low BMI on outcomes and cost are less understood. This study evaluated the relationship between BMI, inpatient costs, complications, readmissions, and utilization of post-acute services. METHODS: A retrospective database analysis of 40,913 primary THAs performed between January 2013 and December 2017 in 29 hospitals was conducted. Operating time, length of stay (LOS), complication rate, 30-day readmission rate, inpatient cost, and utilization of post-acute services were measured and compared in relation to patient BMI. RESULTS: Mean operating time increased with BMI and for BMI > 50 kg/m2 was approximately twice that of BMI 10 kg/m2 to 15 kg/m2. Mean inpatient cost did not vary significantly with BMI. Mean total reimbursement was lowest for the lowest BMI cohort and increased with BMI. Mean LOS was greatest at the extremes of BMI (4.0 days for BMI 10 kg/m2 to 15 kg/m2; 3.75 days for BMI > 50 kg/m2) and twice that of normal BMI. Mean complication rates were greatest in the lowest BMI cohort (16% for BMI 10 kg/m2 to 15 kg/m2) and five times the mean rate of complications in the normal BMI cohorts. Furthermore, 30-day readmissions were greatest in the highest BMI cohort (10% for BMI > 50 kg/m2) and five times the rate for normal BMI patients. CONCLUSION: LOS, complications, and 30-day readmissions all increase at the extremes of BMI and appear to be greater than those of patients with normal BMI. The lowest BMI patients had the lowest payment for inpatient stay yet were at considerable risk for complications and readmission. Patients with extreme BMI should be counselled about their increased risk of complications for THA and nutritional status/obesity optimized preoperatively if possible. Cite this article: Bone Joint J 2020;102-B(7 Supple B):62-70.

The association between oral bacteria, the cough reflex and pneumonia in patients with acute stroke and suspected dysphagia.

OBJECTIVE: To establish how oral bacteria are related to cough sensitivity and pneumonia in a clinical stroke population. BACKGROUND: Stroke patients are at risk of colonisation by respiratory pathogens due, in part, to sudden discontinuation of effective oral hygiene. When combined with reduced cough reflex sensitivity, aspiration of contaminated oropharyngeal contents and can lead to pneumonia. Relationships between oral bacteria, cough sensitivity and pneumonia have not been established. MATERIALS AND METHODS: A total of 102 patients with acute stroke underwent saliva sampling and cough reflex testing at admission to hospital, discharge and one month. A qPCR assay compared levels of bacteria in saliva. Pneumonia events were recorded. RESULTS: Relative levels of bacteria were lowest at admission to hospital (6.04 × 10-6 ). There was a slight (non-significant) increase in bacterial levels at discharge (1.69 × 10-2 , P = .73). By one month, bacterial levels had significantly increased (9.17 × 10-2 ) relative to admission [P < .001] and discharge [P < .001]. Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli are not typically found in healthy mouths, yet were detected in 22% of patients during hospitalisation. Combined bacterial levels measured at one month was associated with pneumonia (P = .004) but there was no relationship to cough sensitivity. CONCLUSION: Acute stroke patients were at increased risk of colonisation from respiratory pathogens throughout their recovery. The presence of these pathogens in saliva at one month was associated with adverse respiratory events. Data support the development of protocols to explore risk factors and sequelae of microbiological changes in stroke.

Reusing Titanium Healing Abutments: Comparison of Two Decontamination Methods.

PURPOSE: To assess the amount of contamination remaining on used healing abutments after autoclaving and to compare the effectiveness of two additional decontamination methods. MATERIALS AND METHODS: After autoclaving, a total of 120 used healing abutments were divided equally into three groups: used healing abutments after autoclaving only (group 1); used healing abutments after autoclaving and air-flow polishing (Master Piezon, EMS) using erythritol powder (AIR-FLOW PLUS, EMS) (group 2); and used healing abutments after autoclaving and sodium hypochlorite (NaOCl; 25 g/L) treatment (group 3). Residual contaminants were stained using Phloxine B (400 g/mL), and healing abutments were photographed using a light microscope with digital capture system (Nikon SMZ800). The proportion of stained (ie, contaminated) areas on each healing abutment was then measured using imaging software (ImageJ). The healing abutments were also examined using scanning electron microscopy (SEM). RESULTS: Mean proportion of surface area affected by residual contaminants on the body, top (screwdriver-engaging), and bottom (implant-abutment interface) surfaces for group 1 was 38.2% ± 28.34%, 30.0% ± 19.55%, and 18.7% ± 17.87%, respectively; group 2 showed 3.5% ± 4.90%, 5.3% ± 3.74%, and 5.4% ± 8.49%, respectively; and group 3 showed 0.3% ± 0.16%, 1.9% ± 2.14%, and 0.7% ± 1.02%, respectively. Autoclaving alone was insufficient for successful decontamination, while additional decontamination procedures significantly reduced remaining contaminants. NaOCl was significantly more effective than air polishing. SEM analysis showed no detectable differences in the surface appearance of titanium healing abutments. CONCLUSION: The results show that decontamination of used healing abutments is achievable, thus strengthening the feasibility of reusing healing abutments.

Surface Characteristics and Biofilm Development on Selected Dental Ceramic Materials.

BACKGROUND: Intraoral adjustment and polishing of dental ceramics often affect their surface characteristics, promoting increased roughness and consequent biofilm growth. This study correlated surface roughness to biofilm development with four commercially available ceramic materials. METHODS: Four ceramic materials (Vita Enamic®, Lava™ Ultimate, Vitablocs Mark II, and Wieland Reflex®) were prepared as per manufacturer instructions. Seventeen specimens of each material were adjusted and polished to simulate clinical intraoral procedures and another seventeen remained unaltered. Specimens were analysed by SEM imaging, confocal microscopy, and crystal violet assay. RESULTS: SEM images showed more irregular surface topography in adjusted specimens than their respective controls. Surface roughness (Ra ) values were greater in all materials following adjustments. All adjusted materials with the exception of Vitablocs Mark II promoted significantly greater biofilm growth relative to controls. CONCLUSION: Simulated intraoral polishing methods resulted in greater surface roughness and increased biofilm accumulation.

Antimicrobial activity of chemomechanical gingival retraction products.

BACKGROUND: Application of astringent hemostatic agents is the most widely used technique for gingival retraction, and a variety of products are offered commercially. However, these products may have additional unintended yet clinically beneficial properties. The authors assessed the antimicrobial activities of marketed retraction products against plaque-associated bacteria in both planktonic and biofilm assays, in vitro. METHODS: The authors assessed hemostatic solutions, gels, pellets, retraction cords, pastes, and their listed active agents against a collection of microorganisms by means of conventional agar diffusion and minimum bacteriostatic and bactericidal concentration determinations. The authors then tested the most active products against monospecies biofilms grown on hydroxyapatite disks. RESULTS: All of the tested retraction products exhibited some antimicrobial activity. The results of the most active products were comparable with those of a marketed mouthwash. The listed retraction-active agents displayed relatively little activity when tested in pure form. At 10% dilution, some products evidenced inhibitory activity against most tested bacteria within 3 minutes of exposure, whereas others displayed variable effects after 10 minutes. The most active agents reduced, but did not completely prevent, the metabolic activity of a monospecies biofilm. CONCLUSIONS: Commercial gingival retraction products exhibit antimicrobial effects to various degrees in vitro. Some products display rapid bactericidal activity. The antimicrobial activity is not owing to the retraction-active agents. Biofilm bacteria are less sensitive to the antimicrobial effects of the agents. PRACTICAL IMPLICATIONS: The rapidity of killing by some hemostatic agents suggests an antimicrobial effect that may be efficacious during clinical placement. The results of this in vitro study suggest that clinicians should be aware of the potential antimicrobial effects of some hemostatic agents, but more research is needed to confirm these observations in clinical use.

Periodontal Application of Manuka Honey: Antimicrobial and Demineralising Effects In Vitro.

Background. Topical application of manuka honey is effective in the treatment of burns and soft-tissue infections. The aim of this study was to assess the antibacterial activity of manuka honey against plaque-associated bacteria in vitro in order to evaluate the potential application as an adjunct to periodontal treatment. Materials and Methods. The minimum bacteriostatic and bactericidal concentrations (MIC and MBC) of manuka honey were compared to those of white clover honey against a variety of plaque-associated bacteria, at the natural and neutral pH. Dissolved calcium was measured following incubation of honeys with hydroxyapatite (HA) beads to assess their potential to demineralise oral hard tissues. Results. Both honeys inhibited most tested oral bacteria at similar MIC/MBC, but Streptococcus mutans was comparatively resistant. The honeys at pH neutral had little effect on antimicrobial activity. Incubation of HA beads in honey solutions resulted in pH-dependent calcium dissolution, and inoculation with S. mutans promoted further demineralisation by both types of honey. Conclusion. Manuka honey is antimicrobial towards representative oral bacteria. However, the relative resistance of S. mutans in association with the high concentrations of fermentable carbohydrates in honey and the direct demineralising effect at natural pH mitigate against the application of honey as an adjunct in the treatment of periodontal disease.

Colony polymerase chain reaction of heme-accumulating bacteria.

Colony PCR of anaerobic black-pigmenting Bacteroidetes species Porphyromonas gingivalis and Prevotella intermedia was modified by addition of bovine serum albumin to reverse the inhibitory action of accumulated heme.