Efficacy of a novel three-step decontamination protocol for titanium-based dental implants: An in vitro and in vivo study

AIM

The aim of the study was to evaluate several mechanical and chemical decontamination methods associated with a newly introduced biofilm matrix disruption strategy for biofilm cleaning and preservation of implant surface features.

MATERIALS AND METHODS

Titanium (Ti) discs were obtained by additive manufacturing. Polymicrobial biofilm-covered Ti disc surfaces were decontaminated with mechanical [Ti curette, Teflon curette, Ti brush, water-air jet device, and Er:YAG laser] or chemical [iodopovidone (PVPI) 0.2% to disrupt the extracellular matrix, along with amoxicillin; minocycline; tetracycline; H2 O2 3%; chlorhexidine 0.2%; NaOCl 0.95%; hydrocarbon-oxo-borate-based antiseptic] protocols. The optimal in vitro mechanical/chemical protocol was then tested in combination using an in vivo biofilm model with intra-oral devices.

RESULTS

Er:YAG laser treatment displayed optimum surface cleaning by biofilm removal with minimal deleterious damage to the surface, smaller Ti release, good corrosion stability, and improved fibroblast readhesion. NaOCl 0.95% was the most promising agent to reduce in vitro and in vivo biofilms and was even more effective when associated with PVPI 0.2% as a pre-treatment to disrupt the biofilm matrix. The combination of Er:YAG laser followed by PVPI 0.2% plus NaOCl 0.95% promoted efficient decontamination of rough Ti surfaces by disrupting the biofilm matrix and killing remnants of in vivo biofilms formed in the mouth (the only protocol to lead to ~99% biofilm eradication).

CONCLUSION

Er:YAG laser + PVPI 0.2% + NaOCl 0.95% can be a reliable decontamination protocol for Ti surfaces, eliminating microbial biofilms without damaging the implant surface.

Translating the determinant aspects on the study design in the dental implant field

Objective

In this article, we analyzed the important categories capable of interfering with the determinants of scientific advancement in the type of study, considering seven leading journals over a 20-year.

Methodology

A bibliometric review was performed at the website of well-established implant dentistry journals in five-time points defined to represent a 20-year period of observation. The measures associated with the type of study design were: the country of origin of the article, country income, continent of the corresponding author, inter-institutional collaboration, interdisciplinary collaboration, type of funding, and topic of research. Logistic regression was used in the multiple models to identify the exploratory factors associated with the type of study.

Results

From a total of 1,944 articles, 50.6% comprised clinical studies. High-income countries and continents stood out for developing more clinical research than others. Since research funders request more collaborative research, overall clinical studies depended upon more inter-institutional collaboration than the others. Most clinical studies were partly supported by research institutes or universities and by industry. About the research topic, the majority of the clinical and animal studies disclosed surgical procedures.

Conclusions

High-income countries and continents are more likely to develop clinical studies in the surgical procedures field. The highest collaborations in terms of the number of institutions and funding sources are more prevalent in clinical research designs. Indeed, most in vivo studies in dental implant fields are performed to evaluate new materials or even new surgical procedures.

In-vitro polymicrobial oral biofilm model represents clinical microbial profile and disease progression during implant-related infections

AIM

Clinically relevant in-vitro biofilm models are essential and valuable tools for mechanistically dissecting the etiopathogenesis of infectious diseases and test new antimicrobial therapies. Thus, the aim of this study was to develop and test a clinically relevant in-vitro oral polymicrobial biofilm model that mimics implant-related infections in terms of microbial profile.

METHODS AND RESULTS

For this purpose, 24-well plate system was used to model oral biofilms, using three different microbial inoculums to grow in-vitro biofilms: (1) human saliva from periodontally healthy patients; (2) saliva as in inoculum 1 + Porphyromonas gingivalis strain; and (3) supra and subgingival biofilm collected from peri-implant sites of patients diagnosed with peri-implantitis. Biofilms were grown to represent the dynamic transition from an aerobic to anaerobic community profile. Subsequently, biofilms were collected after each phase and evaluated for microbiological composition, microbial counts, biofilm biomass, structure, and susceptibility to chlorhexidine (CHX). Results showed higher live cell count (P < .05) for biofilms developed from patients' biofilm inoculum, but biomass volume, dry weight, and microbiological composition were similar among groups (P > .05). Interestingly, according to the checkerboard DNA-DNA hybridization results, the biofilm developed from stimulated human saliva exhibited a microbial composition more similar to the clinical subgingival biofilm of patients with peri-implantitis, with proportions of the main pathogens closer to those found in the disease. In addition, biofilm developed using saliva as inoculum was shown to be susceptible to CHX with significant reduction in bacteria compared with biofilms without exposure to CHX (P < .05).

CONCLUSION

The findings suggested that the in-vitro polymicrobial biofilm developed from human saliva as inoculum is a suitable model and clinically relevant tool for mimicking the microbial composition of implant-related infections.

Factors and clinical outcomes for standard and mini-implants retaining mandibular overdentures: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Standard-diameter dental implants are not always applicable because of anatomic limitations of the residual ridge. Thus, mini-implants have been increasingly used and offer an alternative. However, data regarding prosthetic complications, maintenance factors, and clinical outcomes are limited.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare prosthetic complications and maintenance events and clinical outcomes in residual ridges rehabilitated with mandibular implant overdentures (IODs) by using standard implants or mini-implants.

MATERIAL AND METHODS

Nine electronic databases were searched. Quantitative analyses to measure the risk ratio (RR) and standardized mean difference (SMD) were applied. Those methods were used to assess prosthetic complications and maintenance events (abutment adjustments, replacement of retentive element, occlusal adjustment, and overdenture fracture) and clinical outcomes related to postoperative pain, probing depth (PD), plaque index (PI), marginal bone loss (MBL), and implant survival rate.

RESULTS

Altogether, 7 publications were selected. Mini-implants presented reduced abutment adjustments (RR 0.23 [0.07, 0.73], P=.01), replacement of retentive element (RR 0.41 [0.31, 0.54], P<.001), occlusal adjustment (RR 0.53 [0.31, 0.91], P=.02), and overdenture fracture (RR 0.46 [0.23, 0.94], P=.03) compared with standard implants. Additionally, mini-implants presented lower values for PI at 6 months (SMD -0.27 [-0.47, -0.08], P=.006) and 12 months (SMD -0.25 [-0.46, -0.05], P=.01). No additional tangible differences were noted.

CONCLUSIONS

Mini-implants might be an alternative choice based on the number of prosthetic complications and maintenance events. This was also confirmed by the comparable clinical data between standard implants and mini-implants.

Funding assistance and global productivity in the field of implant overdentures: A bibliometric analysis of 35 years

STATEMENT OF PROBLEM

Implant overdentures have been widely used as a treatment option for edentulous patients. However, the development of implants, aside from commercial growth, requires funding assistance to determine scientific reliability and clinical applications. Nonetheless, bibliometric studies in the implant overdenture field are lacking.

PURPOSE

The purpose of this bibliometric analysis was to evaluate the prevalence of funding and its bibliometric associated parameters according to the financial assistance granted and the implant overdenture documentation over time.

MATERIAL AND METHODS

Six databases were assessed, and 12 bibliometric parameters related to the economy, geographical origin, publication details, and corresponding author metrics were recorded. An incidence rate ratio was applied by using a multiple Poisson regression model (α=.05) to assess the association between funding and each bibliometric parameter.

RESULTS

In total, 1369 studies published between 1986 and 2021 were assessed bibliometrically. The prevalence of funded studies was 34.8% (n=477). The parameter associated with the presence of funding was country income (P<.01), with those having a high and upper-middle income being more funded than those with a lower-middle and low income. Oceania and South America were the continents more frequently funded (P<.05), with Africa being the least frequent. Randomized and nonrandomized controlled trials, in vitro studies, and in silico studies were more funded (P<.001) than case reports and series. Stud and ball attachment systems were more funded (P<.01) than studies with more than 1 retention system. Funding increased over time (P<.01), and corresponding authors with a higher h-index had more studies funded (P<.05).

CONCLUSIONS

The number of funded studies on implant overdentures increased over the years. Other bibliometric parameters such as country income, continent, study design, retention system, and corresponding author h-index were associated with the frequency of funded studies published.

Clinical efficacy of triclosan-containing toothpaste in peri-implant health: A systematic review and meta-analysis of randomized clinical trials

STATEMENT OF PROBLEM

Recent evidence suggests that toothpaste containing 0.3% triclosan (TCS) is more effective than regular toothpaste in improving clinical periodontal conditions. However, a consensus on whether TCS favors a healthy peri-implant environment is limited.

PURPOSE

The purpose of this systematic review and meta-analysis of randomized clinical trials was to determine the effects of TCS-containing toothpaste on dental implant health based on clinical, immunological, and microbiological parameters, as well as on reported adverse events.

MATERIAL AND METHODS

Clinical studies comparing peri-implant conditions in participants by using TCS toothpaste versus conventional fluoride toothpaste (control) were extracted from 9 databases. The studies were assessed with the Cochrane risk-of-bias tool for randomized clinical trials (RoB 2). Datasets for bleeding on probing (BOP), probing depth (PD), clinical attachment level (CAL), gingival index (GI), plaque index (PI), osteo-immunoinflammatory mediators, and bacterial load were plotted, and the standard mean difference (SMD) quantitative analysis was applied by using the Rev Man 5.3 software program. Adverse effects reported by the studies were also tabulated. The certainty of evidence was assessed by using the grading of recommendations assessment, development, and evaluation approach.

RESULTS

Six studies were included in the meta-analyses. BOP was higher in the control group than in the TCS toothpaste group at 3 months (SMD -0.59 [-1.11, -.07] P=.002, I2=77%) and 6 months (SMD -0.59 [-0.83, -0.34] P=.009, I2=79%). PD (SMD -0.04 [-0.08, -0.00] P=.04, I2=0%) was also deeper in the control group versus TCS toothpaste at 6 months (SMD -0.41 [-0.73, -0.10] P=.04, I2=77%). CAL, GI, and PI did not differ between groups (P>.05). Among the osteo-immunoinflammatory mediators, IL-10 levels increased, and IL-1β and osteoprotegerin levels decreased in the TCS toothpaste group (P<.05). Microbiological findings found that TCS toothpaste prevented the growth of periodontal pathogens, specifically in up to approximately 20% of the Prevotella intermedia. Adverse effects were not reported after toothbrushing in either group. However, most studies had "some" or "high" risk of bias, and the certainty of the evidence was considered to be "very low."

CONCLUSIONS

Most studies were short-term (3 and 6 months) analyses, and the results found that, although TCS-containing toothpaste had positive osteo-immunoinflammatory and microbiologic results, clinical parameters, including CAL, GI, and PI, were not influenced.

Clinical performance of and patient satisfaction with conventional complete dentures with different occlusal schemes: A systematic review of systematic reviews

STATEMENT OF PROBLEM

The complete denture occlusal scheme may influence clinical performance and patient satisfaction. However, a consensus on which occlusal scheme should be used for complete denture users is lacking. As a result, many dentists choose the scheme based on their preferences and clinical experience.

PURPOSE

The purpose of this review was to assess the methodological quality and summarize the scientific evidence from secondary studies about the influence of occlusal schemes on the clinical performance of and patient satisfaction with complete dentures.

MATERIAL AND METHODS

Ten sources were surveyed according to the patient, intervention, comparison, outcome (PICO) strategy. Systematic reviews that evaluated the clinical performance and patient satisfaction (O) of rehabilitated edentulous patients with conventional complete dentures (P) under different occlusal schemes (I/C) were included. Methodological quality was assessed by using A MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2 tool by 2 authors independently. The effect of each occlusal scheme in comparison with others was summarized and classified as positive, neutral, negative, or inconclusive based on the conclusions of the systematic review concerning clinical performance and patient satisfaction outcomes.

RESULTS

The search led to the inclusion of 10 systematic reviews. Seven were classified as of critically low, 2 as low, and 1 as moderate methodological quality. The following occlusal designs were included and analyzed: bilateral balanced occlusion, lingualized occlusion, canine guidance, group function, and monoplane occlusion. Bilateral balanced occlusion and canine guidance obtained satisfactory results for both outcomes. Lingualized occlusion showed a trend toward better results than other occlusal schemes for normal and resorbed ridges. Group function presented mainly inconclusive results, and monoplane occlusion did not deliver satisfactory outcomes.

CONCLUSIONS

The present overview concluded that occlusal schemes might interfere with the clinical performance of and patient satisfaction with complete dentures. Lingualized, bilateral balanced, and canine guidance are preferred compared with monoplane occlusion, but lingualized occlusion tends to show better results in some reviews. However, the results should be carefully considered because of the low quality of the systematic reviews included.

The race for the optimal antimicrobial surface: perspectives and challenges related to plasma electrolytic oxidation coating for titanium-based implants

Plasma electrolytic oxidation (PEO) is a low-cost, structurally reliable, and environmentally friendly surface modification method for orthopedic and dental implants. This technique is successful for the formation of porous, corrosion-resistant, and bioactive coatings, besides introducing antimicrobial compounds easily. Given the increase in implant-related infections, antimicrobial PEO-treated surfaces have been widely proposed to surmount this public health concern. This review comprehensively discusses antimicrobial implant surfaces currently produced by PEO in terms of their in vitro and in vivo microbiological and biological properties. We present a critical [part I] and evidence-based [part II] review about the plethora of antimicrobial PEO-treated surfaces. The mechanism of microbial accumulation on implanted devices and the principles of PEO technology to ensure antimicrobial functionalization by one- or multi-step processes are outlined. Our systematic literature search showed that particular focus has been placed on the metallic and semi-metallic elements incorporated into PEO surfaces to facilitate antimicrobial properties, which are often dose-dependent, without leading to cytotoxicity in vitro. Meanwhile, there are concerns over the biocompatibility of PEO and its long-term antimicrobial effects in animal models. We clearly highlight the importance of using clinically relevant infection models and in vivo long-term assessments to guarantee the rational design of antimicrobial PEO-treated surfaces to identify the 'finish line' in the race for antimicrobial implant surfaces.

Bibliometric assessment in implant-retained overdenture articles: Mapping citation and journal impact factor trends

STATEMENT OF PROBLEM

Implant-retained overdentures are a recognized treatment option. However, a comprehensive assessment of all articles on implant-retained overdentures to identify publication standards such as mean citation and the Journal Citation Reports (JCR) impact factor is lacking.

PURPOSE

The purpose of this bibliometric assessment was to evaluate the association of mean citation and JCR impact factor with bibliometric parameters in articles on implant-retained overdentures.

MATERIAL AND METHODS

Articles reporting randomized controlled clinical trials (RCTs) and nonrandomized controlled clinical trials (N-RCTs); case reports and series; retrospective studies; and in silico, in vitro, or systematic reviews in 6 databases were included. Data were extracted, and 2 multiple Poisson regressions analyses were applied (α=.05). The dependent variables were mean citation and JCR impact factor, which were evaluated to identify their association with bibliometric parameters by using prevalence ratio (PR) values.

RESULTS

A total of 1369 articles published from 1986 to 2021 were included. The data revealed a high mean citation and high JCR impact factor for RCT, N-RCT, retrospective, and in vitro studies (P<.05). In silico studies presented a high mean citation (P<.001). Senior researchers with a high h-index were more likely to have a high mean citation and publications with a high JCR impact factor (P<.001). Also, senior authors associated with an international network were more likely to have a high mean citation (P=.001). High-income countries had more studies with a high mean citation and JCR impact factor (P<.05). Higher JCR impact factors were associated with articles evaluating only the maxilla or mandible (P<.05). The topics "implant setting" and "macrodesign" were associated with a high mean citation (P<.05).

CONCLUSIONS

The publication trends suggest a high mean citation and a high JCR impact factor for clinical designs (RCT, N-RCT, retrospective) and in vitro studies. The same pattern was also displayed for researchers with a high h-index and located in high-income countries.

Mapping the trends and impact of research collaboration between countries in oral implantology publications: A bibliometric analysis from 1999 to 2019

STATEMENT OF PROBLEM

Scientific collaboration provides a suitable strategy for enhancing the exchange of knowledge and technological development. However, the impact of collaboration in oral implantology research between countries and how it has been influenced by the income status of the country has not been previously evaluated.

PURPOSE

The purpose of this bibliometric analysis was to evaluate how collaboration between countries affected oral implant publications and whether patterns of collaboration differ depending on the country's income.

MATERIAL AND METHODS

Articles were retrieved from 7 well-established journals whose scope included oral implantology at 5 time points (1999, 2004, 2009, 2014, and 2019). Data were extracted, and descriptive, bivariate, and multivariate logistic regression analyses were performed (α=.05).

RESULTS

A total of 1944 articles were included; of which, 27.5% presented collaboration between countries. In 2009, 2014, and 2019, collaboration between countries was more likely to occur than at previous time points (P≤.005). Corresponding authors with a higher h-index (P<.05) and authors from Europe and North America (P<.001) were more likely to establish international connections. The possibility of collaboration between countries was higher for animal studies (P<.001) and for articles published by Clinical Oral Implants Research (P=.026). Collaborations between high-income and upper-middle- or lower-middle-income countries were more likely to happen in 2014 and 2019 (P<.05), as well as when the number of authors was higher (P=.015), compared with collaboration between high-income countries. With regard to the continent, European articles were less likely to have collaborations with upper-middle- or lower-middle-income countries (P<.001).

CONCLUSIONS

The findings revealed that some parameters related to the study, authors, countries, and journals were statistically associated with the presence of collaboration between countries. However, the bibliometric parameters showed different trends when countries of different incomes established collaboration.

The Effect of Smoking and Brushing on the Color Stability and Stainability of Different CAD/CAM Restorative Materials

This study aimed to investigate and compare the color stability and stainability of computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials in their glazed (G) and polished (P) state when exposed to cigarette smoke, as well as after brushing. Three CAD/CAM restorative materials were investigated: lithium disilicate CAD (LD), zirconia (Zr), and Telio PMMA CAD (PMMA), according to their surface finishing and assignment to cigarette smoking exposure or soaking in the saliva (control) group. The color change (∆E) was calculated before and after the intervention performed for all specimens, using the L*a*b values to quantitatively assess the shade differences. Statistical analysis was performed using one-way repeated measures ANOVA and Bonferroni multiple comparison analysis (α = 0.05). The surface finishing did not influence the materials’ stainability. Color change was noted after smoking, LD and Zr-G and Zr-P had a comparable color change (p > 0.05), while PMMA presented lower ∆E values (p < 0.05). After brushing, all specimens had a significant color change that was high for LD-G and LD-P, and Zr-G, compared with Zr-P and PMMA (p < 0.05). In conclusion, the exposure to cigarette smoke showed that LD, Zr, and PMMA are all susceptible to staining, but brushing decreases surface staining.

Industry support for dental implant research: A metatrend study of industry partnership in the development of new technologies

STATEMENT OF PROBLEM

Industry needs scientific knowledge to develop new products and services, and their financial support to dental implant researchers translates into commercial products. Therefore, identifying the relevant factors for a successful industry partnership is important.

PURPOSE

The purpose of this study was to provide a 20-year bibliometric overview of industry-sponsored studies in implant dentistry to identify possible factors involved in industry partnership motivations.

MATERIAL AND METHODS

A hand search of 6 of the most established journals in the implant dentistry field was performed for articles published in 1999, 2004, 2009, 2014, and 2019. Information regarding the continent of origin of the corresponding author, interinstitute collaboration, type and topic of research, and the h-index of the corresponding author was recorded for each included article. Bivariate and multivariate logistic regression was used to determine statistical relationship between industry support and exploratory factors (α=.05).

RESULTS

A 6% increase in the chance of industry investment was observed over the years (odds ratio [OD]=1.06; P<.001). Studies from North America (OD=4.87; P<.001) and Europe (OD=3.13; P<.001) were more likely to receive industry funding. Data also revealed a direct relationship between the increasing number of institutions involved in the study and the probability of industry funding (OD=1.21; P<.001). Animal studies (OD=2.26; P<.001) about surgical procedures and prosthodontic topics (OD=1.40; P=.044) stood out for having greater industry support. Researchers with an h-index between 31 and 40 were more likely to receive industry financial support (OD=2.46; P=.001).

CONCLUSIONS

Industry support for dental implant research was closely aligned with the continent of origin, interinstitute collaboration, type and topic of research, and the h-index of the corresponding author.

Polymicrobial biofilms related to dental implant diseases: unravelling the critical role of extracellular biofilm matrix

Biofilms are complex tri-dimensional structures that encase microbial cells in an extracellular matrix comprising self-produced polymeric substances. The matrix rich in extracellular polymeric substance (EPS) contributes to the unique features of biofilm lifestyle and structure, enhancing microbial accretion, biofilm virulence, and antimicrobial resistance. The role of the EPS matrix of biofilms growing on biotic surfaces, especially dental surfaces, is largely unravelled. To date, there is a lack of a broad overview of existing literature concerning the relationship between the EPS matrix and the dental implant environment and its role in implant-related infections. Here, we discuss recent advances in the critical role of the EPS matrix on biofilm growth and virulence on the dental implant surface and its effect on the etiopathogenesis and progression of implant-related infections. Similar to other biofilms associated with human diseases/conditions, EPS-enriched biofilms on implant surfaces promote microbial accumulation, microbiological shift, cross-kingdom interaction, antimicrobial resistance, biofilm virulence, and, consequently, peri-implant tissue damage. But intriguingly, the protagonism of EPS role on implant-related infections and the development of matrix-target therapeutic strategies has been neglected. Finally, we highlight the need for more in-depth analyses of polymicrobial interactions within EPS matrix and EPS-targeting technologies' rationale for disrupting the complex biofilm microenvironment with more outstanding translation to implant applications in the near future.

Association between industry support and the reporting of study outcomes in randomized clinical trials of dental implant research from the past 20 years

BACKGROUND

Industry support is a significant funding source in implant dentistry research, not only to provide regulatory processes, but also to validate and promote products through randomized clinical trials (RCTs). However, industry funding should not affect scientific outcomes.

PURPOSE

The aim of this study was to investigate whether there is an association between industry support for RCTs in implant dentistry and a greater chance of the reporting of positive outcomes, and whether there are other funding tendencies.

MATERIALS AND METHODS

Randomized clinical trials from five implant dentistry journals were reviewed. Data were extracted, and descriptive and inferential statistical analyses (α = 0.05), including bivariate and multivariable logistic regression, and Spearman's correlation were performed.

RESULTS

Two hundred eleven RCTs were included. Industry-funded and -unfunded studies presented similar outcomes, in terms of positive and negative results (p ≥ 0.05). North American and European countries received more industry funding, as did high-income countries, which showed well-established collaboration with each other. Clinical Oral Implants Research and Clinical Implant Dentistry and Related Research published 83.6% of industry-funded articles. Industry-funded studies from middle-income countries established more international collaborations with high-income countries than did unfunded studies. Citation numbers were similar for funded and unfunded studies. The chance of RCTs being industry-funded was higher for high-income (odds ratio [OR] = 3.00; 95% confidence interval [CI], 0.99-9.32; p = 0.05) and North American articles (OR = 3.40; 95% CI, 1.37-8.42; p = 0.008) than in lower-middle-income and other continents, respectively. Higher industry funding was associated with specific topics such as "surgical procedures," "prosthodontics topics," and "implant macrodesign" (OR = 4.7; 95% CI, 1.45-15.20; p = 0.010) and with the increase in numbers of institutions (OR = 1.52; 95% CI, 1.16-2.0; p = 0.002).

CONCLUSION

The available evidence suggests no association between industry funding and greater chances of the reporting of positive outcomes in implant dentistry RCTs. A strong association was identified in industry trends concerning geographic origins, higher numbers of institutions, and specific research topics.

Clinical efficacy of anodized dental implants for implant-supported prostheses after different loading protocols: A systematic review and meta-analysis

OBJECTIVES

To summarize the clinical performance of anodized implants connected to different prostheses design after immediate/early (IL) or conventional loading (CL) protocols.

MATERIALS AND METHODS

Seven databases were surveyed for randomized (RCTs) and non-randomized controlled clinical trials (CCTs). Studies comparing IL vs. CL protocol of anodized implants supporting single crown, fixed partial denture (FPD), full-arch fixed dental prosthesis (FDP), or overdenture were included. Risk-of-bias was evaluated using Cochrane Collaboration tools. Meta-analyses for different follow-up were analyzed, followed by heterogeneity source assessment and GRADE approach. The outcomes included implant survival rate, marginal bone loss (MBL), implant stability quotient (ISQ), probing depth (PD), plaque index (PI), and peri-implantitis prevalence.

RESULTS

From 24 eligible studies, 22 were included for quantitative evaluation. Most RCTs (58%, n = 11) and all the 5 CCTs had high and serious risk-of-bias, respectively. Overall, pooling all prosthesis design, no difference between IL vs. CL protocols was observed for all outcomes (p > .05). However, according to prosthesis type subgroups, CL reduced MBL for full-arch FDP (p < .05). In a point-in-time assessment, with overdenture, although IL presented higher PI (12 months), it showed lower MBL (≥24 months), higher ISQ (3 months), and lower PD (6 and 12 months) (p < .05). Conversely, PD was higher for IL in single crown (3 and 6 months) (p < .05). Regarding MBL, IL demonstrated higher mean difference for full-arch FDP (36 months) and FPD (12 and 36 months) (p < .05).

CONCLUSION

Within the limitations of this study, overall, there is no significant difference in the outcomes between IL and CL loading protocols.

Peri-implant and esthetic outcomes of cemented and screw-retained crowns using zirconia abutments in single implant-supported restorations-A systematic review and meta-analysis

OBJECTIVES

To evaluate the peri-implant tissue changes and esthetic outcomes of cemented and screw-retained crowns of single-tooth implants in the esthetic zone using zirconia abutments.

MATERIAL AND METHODS

An electronic search was performed on nine databases. The risk-of-bias was assessed by the revised Cochrane risk-of-bias tool for randomized (RoB 2) and non-randomized (ROBINS-I) clinical trials. Marginal bone level change, soft tissue thickness, bleeding on probing, probing depth, survival rates of implants and crowns, complications, plaque and papilla indexes, and pink esthetic score data were extracted and analyzed. The certainty of evidence was accessed through the GRADE approach.

RESULTS

Nine records were included and 7 were used in the meta-analyses. Screw-retained crowns presented greater marginal bone level change (MD -0.04 [-0.08, -0.00] p = 0.04, I²  = 0%) compared to cemented crowns up to 1-year. At 3 and 4 years no significant differences (p > 0.05) were observed. Soft tissue thickness did not differ between groups (p > 0.05). The bleeding on probing was higher in cemented group than in screw-retained crowns at 1-year (MD 0.17 [0.08, 0.27] p = 0.0005, I²  = 0%), at medium-term periods (3 and 4 years) no statistically significant differences (p > 0.05) were observed for this outcome. Probing depth, survival rates of implants and crowns, complications, and plaque index, as well as esthetic analysis using the papilla index and pink esthetic score did not differ statistically (p > 0.05) between both retention systems at short and medium-term periods.

CONCLUSION

The connection system considering zirconia abutments presented no influence on peri-implant parameters and esthetics evaluation for medium-term periods (3 and 4 years).

Patient-reported outcome measures and clinical assessment of implant-supported overdentures and fixed prostheses in mandibular edentulous patients: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A consensus based on patients' perceptions as to whether to use overdentures or fixed prostheses to rehabilitate mandibular edentulous arches is limited.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the patient-reported outcome measures (PROMs) and clinical outcomes associated with implant-supported overdentures and fixed prostheses in edentulous mandibles.

MATERIAL AND METHODS

Nine electronic databases were searched for randomized clinical trials (RCTs) and nonrandomized clinical trials (N-RCTs). The risk of bias was assessed by the revised Cochrane risk of bias tool for RCTs (RoB 2) and N-RCT (ROBINS-I). Data sets for oral health-related quality of life (OHRQoL), satisfaction, survival rate, implant probing depth, and marginal bone loss were plotted, and the appropriate analyses were applied by using the Rev Man 5.3 software program. Certainty of evidence was also evaluated by means of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Ten eligible trials were included and evaluated quantitatively. For 3 domains of OHRQoL, fixed prostheses showed significantly higher quality of life when compared with overdentures regarding functional limitation (P<.001), physical disability (P=.001), and physical pain (P=.003). Fixed prostheses also improved satisfaction, when compared with overdentures for comfort (P=.02), ease of chewing (P<.001), retention (P<.001), and stability (P<.001). The same pattern was observed for overall OHRQoL (P=.01) and satisfaction (P=.01) in which fixed prostheses improved patient satisfaction. Only ease of cleaning presented greater satisfaction for the overdenture group. Clinical parameters did not differ statistically (P>.05) between both types of prosthesis.

CONCLUSIONS

Fixed rehabilitations for mandibular edentulous patients seem to be a well-accepted treatment from the patients' oral health perspective. However, mandibular overdentures are no less efficient than fixed prostheses in terms of clinical outcomes.

Photofunctionalization as a suitable approach to improve the osseointegration of implants in animal models-A systematic review and meta-analysis

OBJECTIVES

To determine whether photofunctionalization influences dental implant osseointegration.

MATERIAL AND METHODS

Data on osseointegration rates were extracted from 8 databases, based on bone-to-implant contact (BIC) and pushout tests. Internal validity was accessed through the SYRCLE risk of bias tool for animal experimental studies. Meta-analyses were performed for investigation of the influence of photofunctionalization on implant osseointegration, with a random effect and a confidence interval of 95%. The certainty of evidence was accessed through the GRADE approach.

RESULTS

Thirty-four records were identified, and 10 were included in the meta-analysis. Photofunctionalized implants showed higher mean values for BIC in rabbits (MD 6.92 [1.01, 12.82], p = .02), dogs (MD 23.70 [10.23, 37.16], p = .001), rats (MD 20.93 [12.91, 28.95], p < .0001), and in the pooled BIC analyses (MD 14.23 [7.80, 20.66], p < .0001) compared to those in control implants in the overall assay. Conversely, at late healing periods, the pooled BIC meta-analyses showed no statistically significant differences (p > .05) for photofunctionalized and control implants at 12 weeks of follow-up. For pushout analysis, photofunctionalized implants presented greater bone strength integration (MD 19.92 [13.88, 25.96], p < .0001) compared to that of control implants. The heterogeneity between studies ranged from "not important" to "moderate" for rabbits I²  = 24%, dogs I²  = 0%, rats I²  = 0%, and pooled BIC (I²  = 49%), while considerable heterogeneity was observed for pushouts (I²  = 90%).

CONCLUSION

Photofunctionalization improves osseointegration in the initial healing period of implants, as summarized from available data from rabbit, dog, and rat in vivo models.

UV-photofunctionalization of a biomimetic coating for dental implants application

Photofunctionalization mediated by ultraviolet (UV) rays changes the physico-chemical characteristics of titanium (Ti) and improves the biological activity of dental implants. However, the role of UV-mediated photofunctionalization of biofunctional Ti surfaces on the antimicrobial and photocatalytic activity remains unknown and was investigated in this study. Commercially pure titanium (cpTi) discs were divided into four groups: (1) machined samples without UV light application [cpTi UV-]; (2) plasma electrolytic oxidation (PEO) treated samples without UV light application [PEO UV-]; (3) machined samples with UV light application [cpTi UV+]; and (4) PEO-treated samples with UV light application [PEO UV+]. The surfaces were characterized according to their morphology, roughness, crystalline phase, chemical composition and wettability. The photocatalytic activity and proteins adsorption were measured. For the microbiological assay, Streptococcus sanguinis was grown on the disc surfaces for 1 h and 6 h, and the colony forming units and bacterial organization were evaluated. In addition, to confirm the non-cytotoxic effect of PEO UV +, human gingival fibroblast (HGF) cells were cultured in a monolayer onto each material surface and the cells viability and proliferation evaluated by a fluorescent cell staining method. PEO treatment increased the Ti surface roughness and wettability (p < 0.05). Photofunctionalization reduced the hydrocarbon concentration and enhanced human blood plasma proteins and albumin adsorption mainly for the PEO-treated surface (p < 0.05). PEO UV+ also maintained higher wettability values for a longer period and provided microbial reduction at 1 h of bacterial adhesion (p = 0.012 vs. PEO UV-). Photofunctionalization did not increase the photocatalytic activity of Ti (p > 0.05). Confocal microscopy analyses demonstrated that PEO UV+ had no cell damage effect on HGF cells growth even after 24 h of incubation. The photofunctionalization of a biofunctional PEO coating seems to be a promising alternative for dental implants as it increases blood plasma proteins adsorption, reduces initial bacterial adhesion and presents no cytotoxicity effect.

Visible-Light-Induced Photocatalytic and Antibacterial Activity of TiO2 Codoped with Nitrogen and Bismuth: New Perspectives to Control Implant-Biofilm-Related Diseases

Biofilm-associated diseases are one of the main causes of implant failure. Currently, the development of implant surface treatment goes beyond the osseointegration process and focuses on the creation of surfaces with antimicrobial action and with the possibility to be re-activated (i.e., light source activation). Titanium dioxide (TiO₂), an excellent photocatalyst used for photocatalytic antibacterial applications, could be a great alternative, but its efficiency is limited to the ultraviolet (UV) range of the electromagnetic spectrum. Since UV radiation has carcinogenic potential, we created a functional TiO₂ coating codoped with nitrogen and bismuth via the plasma electrolytic oxidation (PEO) of titanium to achieve an antibacterial effect under visible light with re-activation potential. A complex surface topography was demonstrated by scanning electron microscopy and three-dimensional confocal laser scanning microscopy. Additionally, PEO-treated surfaces showed greater hydrophilicity and albumin adsorption compared to control, untreated titanium. Bismuth incorporation shifted the band gap of TiO₂ to the visible region and facilitated higher degradation of methyl orange (MO) in the dark, with a greater reduction in the concentration of MO after visible-light irradiation even after 72 h of aging. These results were consistent with the in vitro antibacterial effect, where samples with nitrogen and bismuth in their composition showed the greatest bacterial reduction after 24 h of dual-species biofilm formation ( Streptococcus sanguinis and Actinomyces naeslundii) in darkness with a superior effect at 30 min of visible-light irradiation. In addition, such a coating presents reusable photocatalytic potential and good biocompatibility by presenting a noncytotoxicity effect on human gingival fibroblast cells. Therefore, nitrogen and bismuth incorporation into TiO₂ via PEO can be considered a promising alternative for dental implant application with antibacterial properties in darkness, with a stronger effect after visible-light application.

Preliminary performance data of the RHE/IL-18 assay performed on SkinEthic™ RHE for the identification of contact sensitizers

OBJECTIVE

The purpose of this study was to evaluate the performances of the RHE/IL-18 assay using the SkinEthic^™ RHE model for the identification of contact sensitizers.

METHODS

A set of 18 substances and mixtures was tested on this epidermal model, following the RHE/IL-18 protocol. The final results of the assay were obtained following 5 interpretation schemes, to determine the optimal prediction model for this assay with this specific test system. The data were analysed with a special focus on the basal level of IL-18 release and on the performance obtained with respect to three different gold standards: LLNA, HRIPT and an integrated reference, constructed from all available results.

RESULTS

No important differences were found in the performance levels depending on the three gold standards. The performances obtained with the SkinEthic^™ RHE model support that this model may be considered as an alternative to different reconstructed epidermis models (EpiDERM^™ , EpiCS^™ and VUMC-EE) for the performance of RHE/IL-18 assays.

CONCLUSION

The prediction model to be used was refined, and more substances have to be tested in order to gather enough data for this evaluation and to determine the right criteria applicable for this assay using the SkinEthic^™ RHE test system.

Treatment of in vitro enterohemorrhagic Escherichia coli infection using phage and probiotics

AIMS

To assay the combination of phage and probiotics against EHEC in vitro on infected Hep-2 cells.

METHODS AND RESULTS

Phage and probiotics treatments on EHEC O157:H7-infected Hep-2 cells were assayed individually or combined. The effect of freeze-drying on phage and probiotic antimicrobial activity was also studied. While treatment with phage alone increased cell detachment caused by EHEC infection, the treatments with MM alone or in combination with phage proved to effectively diminish cell damage caused by EHEC infection. Combined treatment showed a decrease in apoptotic cell count of 57·3% and a reduction in EHEC adhesion to cell monolayer of 1·2 log CFU. The simultaneous use of phage and probiotics showed no antagonistic effect, and freeze-drying did not affect their antipathogenic activity.

CONCLUSIONS

The combination of phage and probiotics has great potential for reducing the number of pathogens adhered to epithelial cells during EHEC O157:H7 infection and attenuating the cytotoxic effect derived from it. Further in vivo assays are needed for assessing the actual effectiveness of the treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study presents a freeze-dried formulation of phage and probiotics capable of controlling EHEC infections and reducing epithelial cell damage in vitro.

Isolation and selection of coliphages as potential biocontrol agents of enterohemorrhagic and Shiga toxin-producing E. coli (EHEC and STEC) in cattle

AIMS

To isolate, characterize and select phages as potential biocontrol agents of enterohemorrhagic and Shiga toxin-producing Escherichia coli (EHEC and STEC) in cattle.

METHODS AND RESULTS

Sixteen STEC and EHEC coliphages were isolated from bovine minced meat and stool samples and characterized with respect to their host range against STEC, EHEC and other Gram-negative pathogens; their morphology by electron microscopy; the presence of the stx1, stx2 and cI genes by means of PCR; RAPD and rep-PCR profiles; plaque formation; and acid resistance. Six isolates belonged to the Myoviridae and 10 to the Podoviridae families. The phages negative for stx and cI that formed large, well-defined plaques were all isolated using EHEC O157:H7 as host. Among them, only CA911 was a myophage and, together with CA933P, had the broadest host range for STEC and EHEC; the latter phage also infected Shigella and Pseudomonas. Isolates CA911, MFA933P and MFA45D differed in particle morphology and amplification patterns by RAPD and rep-PCR and showed the highest acidity tolerance.

CONCLUSIONS

Myophage CA911 and podophages CA933P, MFA933P and MFA45D were chosen as the best candidates for biocontrol of STEC and EHEC in cattle.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work employs steps for a rational selection and characterization of bacteriophages as therapeutic agents. This report constitutes the first documentation of STEC and EHEC phages isolated in Argentina and proposes for the first time the use of rep-PCR as a complement of RAPD on DNA fingerprinting of phages.

Synthesis of sub-micromolar inhibitors of MraY by exploring the region originally occupied by the diazepanone ring in the liposidomycin structure

The synthesis and inhibitory activity against MraY of a series of simplified analogues of liposidomycins are described. These compounds were mainly obtained by performing parallel synthesis in the 6'-position of a scaffold that gathers key features found necessary for the binding to MraY. Thus, inhibitory activity was improved from 5300 to 140 nM. This improvement was correlated with the length and lipophilicity of substituents, but was found to be independent of the nature of the chemical bond generated. In addition, some of these inhibitors presented encouraging antibacterial activities.

Synthesis of analogues of the O-beta-D-ribofuranosyl nucleoside moiety of liposidomycins. Part 2: role of the hydroxyl groups upon the inhibition of MraY

O-beta-D-ribofuranosyl nucleoside I is the minimal structural entity of liposidomycins that maintains enzyme inhibitory activity on MraY. A set of compounds with hydroxyl patterns different from I has been synthesized. The presence of a hydroxyl group in the 3" position is essential for the activity. The 3'-deoxy derivative (IV), however, shows a 5-fold improved potency.

Synthesis of analogues of the O-beta-D-ribofuranosyl nucleoside moiety of liposidomycins. Part 1: contribution of the amino group and the uracil moiety upon the inhibition of MraY

The O-beta-D-ribofuranosyl nucleoside I is the minimal structural entity of liposidomycins maintaining enzyme inhibitory activity. Modifications performed on both the primary amine and the uracil moieties clearly demonstrate their major contribution to the inhibition of the bacterial translocase (MraY).

Synthesis of the nucleoside moiety of liposidomycins: elucidation of the pharmacophore of this family of MraY inhibitors

Tunicamycins (TCMs) and liposidomycins (LPMs) are naturally occurring inhibitors of the bacterial translocase (MraY). Based on structure-activity relationship (SAR) studies, a molecular model has been proposed for their inhibitory mechanism. This study points out the importance of the nucleoside moiety of liposidomycins in the inhibition of MraY. A simplified molecule (I) based on the liposidomycin core structure has been synthesised and tested on MraY. The compound displayed a moderate inhibitory activity (IC50 = 50 microM). The validation of the molecular model was then performed by synthesising higher homologues of I, containing an additional stereocentre in the 5' position (XIV and XV). In agreement with the prediction, only the (S) isomer XV showed significant activity against MraY (IC50 = 5 microM).

Synthesis of a dihydroxythiophene analogue of catechosporines

A vinylogous cephalosporine bearing a dihydroxythiophene moiety as a potential catechol surrogate has been synthesised (I-e-beta). Even if the anti staphylococcus spectrum displayed by this compound is of interest, its activity against Pseudomonas species, expected for such a structure, remains disappointing.

Multi gram synthesis of UDP-N-acetylmuramic acid

As part of an effort to discover novel antibacterial agents, a new and efficient synthesis was established in order to provide a large amount of UDP-N-acetylmuramic acid (UDP-MurNAc).

Is community-based treatment an add-on or a substitution for hospital treatment of alcoholism? Some evidence from Canada

OBJECTIVES

This study determined whether the development of community treatment of alcohol problems acted as an add-on or a substitution for the utilization of inpatient hospital services in Ontario.

METHODS

Complex modelling and graphic analyses using econometric multiple regression techniques were performed on data for the 48 counties of Ontario (Canada) for the period 1972 to 1988, combining both cross-sectional and time series analysis.

RESULTS

After controlling for differences in alcohol consumption, in health care characteristics such as the supply of physicians or hospital occupancy rates, and in socioeconomic characteristics of the population, when community treatment became available, hospital utilization for the treatment of alcohol problems decreased and community services were substituting for hospital treatment. In addition, nonresidential services had an overall greater importance in producing this effect (elasticities at the mean of -0.11 to -0.14 depending on the region) than community-based residential treatment. The effect was larger in the southern than in the northern counties of Ontario. Testing of the modelling techniques showed statistically significant and satisfactory modelling of the forces at work.

CONCLUSIONS

Where community-based treatment was available, it was used in preference to inpatient hospital treatment; however, there may be a slightly more complex relationship present in the southern urban counties (which contain the larger metropolitan areas) than in the northern and southern rural counties..

Circular YAC vectors containing a small mammalian origin sequence can associate with the nuclear matrix

Three different mammalian origins of DNA replication, 343, S3, and X24, have been cloned into a 15.8 kb circular yeast vector pYACneo. Subsequent transfection into HeLa cells resulted in the isolation of several stably maintained clones. Two cell lines, C343e2 and CS3e1, were found to have sequences maintained as episomes in long-term culture with a stability per generation of approximately 80%. Both episomes also contain matrix attachment region (MAR) sequences which mediate the binding of DNA to the nuclear skeleton and are thought to play a role in DNA replication. Using high salt extraction of the nucleus and fluorescent in situ hybridization, we were able to demonstrate an association of the 343 episome with the nuclear matrix, most probably through functional MAR sequences that allow an association with the nuclear matrix and associated regions containing essential replication proteins. The presence of functional MARs in small episomal sequences may facilitate the replication and maintenance of transfected DNA as an episome and improve their utility as small episomal constructs, potential microchromosomes.

Acute spinal trauma: prognostic value of MRI appearances at 0.5 T

Thirty-two patients with post-traumatic myelopathy were examined with a 0.5 T MRI system within 4 days of injury and the MRI findings analysed with respect to the immediate and residual functional deficit and (in 20 patients) the MRI appearances of the spinal cord in the chronic phase. In the acute phase a normal spinal cord was associated with only slight clinical deficit in four patients. Signal abnormalities in the spinal cord at the site of trauma were identified on T2-weighted spin-echo or T2*-weighted gradient-recalled echo images in 28 patients. The 12 most functionally impaired patients showed focal low signal suggestive of intramedullary haemorrhage: the other 16 had homogeneous high signal consistent with diffuse oedema. Swelling of the spinal cord and mild persistent cord compression following reduction were noted in 17 and 26 patients respectively. All patients were treated conservatively other than undergoing surgical decompression. Four died of complications. No patient with low signal in the spinal cord on initial MRI showed significant clinical improvement. Five whose spinal cord was hyperintense remained unchanged, whereas nine made a significant recovery, as did all patients with normal-appearing spinal cords. Cord compression on the initial examination was not relevant to clinical outcome. Intramedullary scars were identified at follow-up in 18 patients and were more extensive in those with haemorrhagic acute lesions. Haemorrhagic contusion of the spinal cord can be demonstrated in the acute phase with midfield MRI and is a valuable predictor of the functional outcome in patients with traumatic myelopathy.