Validating the Assumptions of Population Adjustment: Application of Multilevel Network Meta-regression to a Network of Treatments for Plaque Psoriasis

BACKGROUND

Network meta-analysis (NMA) and indirect comparisons combine aggregate data (AgD) from multiple studies on treatments of interest but may give biased estimates if study populations differ. Population adjustment methods such as multilevel network meta-regression (ML-NMR) aim to reduce bias by adjusting for differences in study populations using individual patient data (IPD) from 1 or more studies under the conditional constancy assumption. A shared effect modifier assumption may also be necessary for identifiability. This article aims to demonstrate how the assumptions made by ML-NMR can be assessed in practice to obtain reliable treatment effect estimates in a target population.

METHODS

We apply ML-NMR to a network of evidence on treatments for plaque psoriasis with a mix of IPD and AgD trials reporting ordered categorical outcomes. Relative treatment effects are estimated for each trial population and for 3 external target populations represented by a registry and 2 cohort studies. We examine residual heterogeneity and inconsistency and relax the shared effect modifier assumption for each covariate in turn.

RESULTS

Estimated population-average treatment effects were similar across study populations, as differences in the distributions of effect modifiers were small. Better fit was achieved with ML-NMR than with NMA, and uncertainty was reduced by explaining within- and between-study variation. We found little evidence that the conditional constancy or shared effect modifier assumptions were invalid.

CONCLUSIONS

ML-NMR extends the NMA framework and addresses issues with previous population adjustment approaches. It coherently synthesizes evidence from IPD and AgD studies in networks of any size while avoiding aggregation bias and noncollapsibility bias, allows for key assumptions to be assessed or relaxed, and can produce estimates relevant to a target population for decision-making.

HIGHLIGHTS

Multilevel network meta-regression (ML-NMR) extends the network meta-analysis framework to synthesize evidence from networks of studies providing individual patient data or aggregate data while adjusting for differences in effect modifiers between studies (population adjustment). We apply ML-NMR to a network of treatments for plaque psoriasis with ordered categorical outcomes.We demonstrate for the first time how ML-NMR allows key assumptions to be assessed. We check for violations of conditional constancy of relative effects (such as unobserved effect modifiers) through residual heterogeneity and inconsistency and the shared effect modifier assumption by relaxing this for each covariate in turn.Crucially for decision making, population-adjusted treatment effects can be produced in any relevant target population. We produce population-average estimates for 3 external target populations, represented by the PsoBest registry and the PROSPECT and Chiricozzi 2019 cohort studies.

Methods used for indirect comparisons of systemic treatments for psoriasis. A systematic review

Background

Indirect comparisons (including network meta-analyses [NMAs]) allow us to compare benefits and risks of multiple interventions for the same clinical condition when head-to-head comparisons are not feasible.

Objective

To provide guidance to the clinical community on better understanding indirect comparison methods to help them to interpret their results by applying two quality standards to published indirect comparisons of systemic biologics for moderate to severe psoriasis.

Methods

A systematic literature review (SLR) of published indirect comparisons of biologics for the treatment of moderate to severe psoriasis in adults was conducted. Data extraction was performed using a predefined subset of NICE TSD7 (National Institute for Health and Care Excellence Technical Support Document 7) checklist questions and methods used to perform each analysis were descriptively compared. Methodological quality of the SLR underlying each indirect comparison was assessed using AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews version 2).

Results

Twenty-two NMAs and four adjusted indirect comparisons (AICs) were identified. Although there were some similarities, for example, application of Bayesian random-effects models, several important methodological aspects varied considerably across NMAs identified, for example, classes of drugs, number of treatments and studies included, reporting and handling of different doses, and reporting of both checks for and investigations of inconsistency. Methodological comparisons across AICs were limited by the small number. The quality of most underlying SLRs described, assessed as overall level of confidence in the results, was 'critically low'.

Conclusions

Understanding that there are different methodologies employed to answer differing research questions is key to helping clinicians to interpret the indirect evidence currently available in psoriasis.

Cardiac Rehabilitation in German Speaking Countries of Europe-Evidence-Based Guidelines from Germany, Austria and Switzerland LLKardReha-DACH-Part 2

Background: Scientific guidelines have been developed to update and harmonize exercise based cardiac rehabilitation (ebCR) in German speaking countries. Key recommendations for ebCR indications have recently been published in part 1 of this journal. The present part 2 updates the evidence with respect to contents and delivery of ebCR in clinical practice, focusing on exercise training (ET), psychological interventions (PI), patient education (PE). In addition, special patients’ groups and new developments, such as telemedical (Tele) or home-based ebCR, are discussed as well. Methods: Generation of evidence and search of literature have been described in part 1. Results: Well documented evidence confirms the prognostic significance of ET in patients with coronary artery disease. Positive clinical effects of ET are described in patients with congestive heart failure, heart valve surgery or intervention, adults with congenital heart disease, and peripheral arterial disease. Specific recommendations for risk stratification and adequate exercise prescription for continuous-, interval-, and strength training are given in detail. PI when added to ebCR did not show significant positive effects in general. There was a positive trend towards reduction in depressive symptoms for “distress management” and “lifestyle changes”. PE is able to increase patients’ knowledge and motivation, as well as behavior changes, regarding physical activity, dietary habits, and smoking cessation. The evidence for distinct ebCR programs in special patients’ groups is less clear. Studies on Tele-CR predominantly included low-risk patients. Hence, it is questionable, whether clinical results derived from studies in conventional ebCR may be transferred to Tele-CR. Conclusions: ET is the cornerstone of ebCR. Additional PI should be included, adjusted to the needs of the individual patient. PE is able to promote patients self-management, empowerment, and motivation. Diversity-sensitive structures should be established to interact with the needs of special patient groups and gender issues. Tele-CR should be further investigated as a valuable tool to implement ebCR more widely and effectively.

Dynamic Visual Representation of Clinical Efficacy of Ixekizumab in Psoriasis

Introduction

Ixekizumab, a high-affinity monoclonal antibody that selectively targets interleukin-17A, is an approved treatment for plaque psoriasis. This study aimed to use animated visualizations as a tool to simplify complex data from ixekizumab clinical trials.

Methods

Animated visualizations were developed to show outcomes from ixekizumab clinical trials and a Bayesian network meta-analysis of 11 approved biologics. The visualizations simultaneously highlighted both aggregate scores and the individual progression of patients over the course of treatment.

Results

The animations provided key messages and information from the complex data in efficient and scientific ways that were also visually pleasing and simple to understand. The animations highlighted (1) rapid reduction in disease severity from baseline; (2) sustained efficacy of ixekizumab in the treatment of skin and nail psoriasis; (3) side-by-side comparisons of treatment efficacy and clinical improvement across trials; (4) simultaneous visual presentation of individual results with summary response over time; and (5) indirect comparison of relative treatment effects with other biologics based on Bayesian network meta-analysis.

Conclusion

The rapid and sustained efficacy of ixekizumab in the treatment of psoriasis was demonstrated using multiple dynamic visualizations with different clinical endpoints. Animated visualizations provided a simpler and more comprehensive understanding of complex data than conventional static figures.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-021-00548-2.

Cardiac Rehabilitation in German Speaking Countries of Europe-Evidence-Based Guidelines from Germany, Austria and Switzerland LLKardReha-DACH-Part 1

BACKGROUND

Although cardiovascular rehabilitation (CR) is well accepted in general, CR-attendance and delivery still considerably vary between the European countries. Moreover, clinical and prognostic effects of CR are not well established for a variety of cardiovascular diseases.

METHODS

The guidelines address all aspects of CR including indications, contents and delivery. By processing the guidelines, every step was externally supervised and moderated by independent members of the "Association of the Scientific Medical Societies in Germany" (AWMF). Four meta-analyses were performed to evaluate the prognostic effect of CR after acute coronary syndrome (ACS), after coronary bypass grafting (CABG), in patients with severe chronic systolic heart failure (HFrEF), and to define the effect of psychological interventions during CR. All other indications for CR-delivery were based on a predefined semi-structured literature search and recommendations were established by a formal consenting process including all medical societies involved in guideline generation.

RESULTS

Multidisciplinary CR is associated with a significant reduction in all-cause mortality in patients after ACS and after CABG, whereas HFrEF-patients (left ventricular ejection fraction <40%) especially benefit in terms of exercise capacity and health-related quality of life. Patients with other cardiovascular diseases also benefit from CR-participation, but the scientific evidence is less clear. There is increasing evidence that the beneficial effect of CR strongly depends on "treatment intensity" including medical supervision, treatment of cardiovascular risk factors, information and education, and a minimum of individually adapted exercise volume. Additional psychologic interventions should be performed on the basis of individual needs.

CONCLUSIONS

These guidelines reinforce the substantial benefit of CR in specific clinical indications, but also describe remaining deficits in CR-delivery in clinical practice as well as in CR-science with respect to methodology and presentation.

Network meta-analysis of biologic treatments for psoriasis using absolute Psoriasis Area and Severity Index values ≤1, 2, 3 or 5 derived from a statistical conversion method

BACKGROUND

In practice, the goal of treatment for patients with psoriasis is to achieve almost clear or clear skin and maintain disease control, regardless of baseline disease severity. However, identifying absolute Psoriasis Area and Severity Index (PASI) values for new treatment goals is challenging, as most clinical trials report relative PASI 50, 75, 90 or 100 improvements but rarely absolute PASI values achieved.

OBJECTIVE

Our objective was to illustrate a statistical conversion method that was developed to derive absolute PASI values from available clinical trial data on relative PASI improvements. The results of network meta-analyses (NMAs) based on these derived data were then compared with those of NMAs based on the corresponding relative PASI improvement data for selected biologics for moderate-to-severe psoriasis.

METHODS

The PASI statistical conversion method was applied to relative PASI improvement data for 11 biologic treatment regimens and placebo at 12 weeks using data from 50 published studies. The respective proportions of patients reaching absolute PASI values ≤1, 2, 3 or 5 were then calculated. Frequentist NMAs (Rücker method) were subsequently used to compare efficacy results across relative and absolute PASI data.

RESULTS

The ranking of included treatment regimens for patients achieving absolute PASI 0 to 8 was aligned with results for relative PASI scores (from 100 to 60) at end of induction therapy. Across the range of PASI scores considered, the most effective treatment regimens based on both absolute and relative PASI NMAs were brodalumab 210 mg every 2 weeks and ixekizumab 80 mg every 2 weeks, followed by guselkumab 100 mg every 8 weeks and risankizumab 150 mg every 12 weeks.

CONCLUSION

Data generated using this mathematical model will be useful to inform ongoing scientific discussions on treatment goals in the absence of primary absolute PASI data for all available treatments for moderate-to-severe plaque psoriasis.

Posttraumatic Perfusion Analysis of Quadriceps, Patellar, and Achilles Tendon Regeneration With Dynamic Contrast-Enhanced Ultrasound and Dynamic Contrast-Enhanced Magnetic Resonance Imaging: Preliminary Results

OBJECTIVES

The healing process of tendons after surgical treatment of tendon ruptures mainly depends on the perfusion of the tendon and its surrounding tissue. Dynamic contrast-enhanced ultrasound (DCE-US) and dynamic contrast-enhanced MRI (DCE-MRI) can provide additional information about the local microperfusion. In this pilot study, the feasibility of these techniques to assess the vascularization during tendon regeneration was evaluated.

METHODS

Between 2013 and 2015, 23 patients with surgical treatment of traumatic rupture of quadriceps, patellar, and Achilles tendons were involved. All patients received clinical follow-up examinations at 6, 12, and at least 52 weeks postoperatively. Dynamic contrast-enhanced US and DCE-MRI examinations were performed 6 and 12 weeks postoperatively. Dynamic contrast-enhanced US perfusion was quantified by the parameters peak enhancement, wash-in area under the curve, rise time, and initial area under the curve. Correlations between these parameters were examined via the Spearman rank correlation. The clinical and functional outcomes were assessed via the Lysholm Knee Score and Knee and Osteoarthritis Outcome Score at 12 and 52 weeks postoperatively.

RESULTS

Fourteen patients with quadriceps (n = 8), patellar (n = 4) and Achilles (n = 2) tendon ruptures with complete follow-up were available. The microperfusion could be successful assessed. We could detect a strong correlation of DCE-US (peak enhancement) parameters with DCE-MRI (initial area under the curve) parameters after 6 and 12 weeks.

CONCLUSIONS

In this pilot study, DCE-US was able to visualize the microperfusion of healing tendons with a strong correlation with DCE-MRI. Our initial results are in favor of DCE-US as a potential quantitative imaging tool for evaluating the vascularization in tendon regeneration as a complementary method.

Impact of clinical and demographic characteristics on patient preferences for psoriasis treatment features: Results from a discrete-choice experiment in a multicountry study

OBJECTIVES

This study aimed to elicit preferences for psoriasis treatment features and to test for preference heterogeneity across groups of respondents.

MATERIALS AND METHODS

A discrete-choice experiment was employed to elicit preferences of patients with plaque psoriasis in multiple countries. The survey instrument included a series of choice questions between three hypothetical treatments, each characterized by varying levels of six attributes (namely, lesion reduction, risk of impairing side effects, time to reach results, mode and frequency of administration, itching reduction, and side effects). Random parameters logit was used to model the data. Results were compared across a total of 18 subgroup sets.

RESULTS

The data analysis from 1,123 respondents showed that, on average, respondents receive more utility gain from higher levels of lesion reduction and lower risks of impairing side effects than changes in other attributes included in the study. Systematic differences were detected for 13 sets; the most pronounced differences were observed based on disease severity, nail psoriasis, biologic experience, and quality-of-life scores.

CONCLUSION

These many sources of preference heterogeneity identified by our analysis suggest that to improve patient satisfaction and, probably, adherence and persistence, clinicians should discuss options with patients when prescribing their treatment.

Multilevel network meta-regression for population-adjusted treatment comparisons

Standard network meta-analysis (NMA) and indirect comparisons combine aggregate data from multiple studies on treatments of interest, assuming that any effect modifiers are balanced across populations. Population adjustment methods relax this assumption using individual patient data from one or more studies. However, current matching-adjusted indirect comparison and simulated treatment comparison methods are limited to pairwise indirect comparisons and cannot predict into a specified target population. Existing meta-regression approaches incur aggregation bias. We propose a new method extending the standard NMA framework. An individual level regression model is defined, and aggregate data are fitted by integrating over the covariate distribution to form the likelihood. Motivated by the complexity of the closed form integration, we propose a general numerical approach using quasi-Monte-Carlo integration. Covariate correlation structures are accounted for by using copulas. Crucially for decision making, comparisons may be provided in any target population with a given covariate distribution. We illustrate the method with a network of plaque psoriasis treatments. Estimated population-average treatment effects are similar across study populations, as differences in the distributions of effect modifiers are small. A better fit is achieved than a random effects NMA, uncertainty is substantially reduced by explaining within- and between-study variation, and estimates are more interpretable.

Modeling Heterogeneity in Patients' Preferences for Psoriasis Treatments in a Multicountry Study: A Comparison Between Random-Parameters Logit and Latent Class Approaches

BACKGROUND

Either a random-parameters logit (RPL) or latent class (LC) model can be used to model or explain preference heterogeneity in discrete-choice experiment (DCE) data. The former assumes continuous distribution of preferences across the sample, while the latter assumes a discrete distribution. This study compared RPL and LC models to explore preference heterogeneity when analyzing patient preferences for psoriasis treatments.

METHODS

Using DCE data collected from respondents with moderate-to-severe plaque psoriasis, we calculated and compared preference weights derived from RPL and LC models. We then compared how RPL and LC explain preference heterogeneity by exploring differences across subgroups defined by observed characteristics (i.e., country, age, gender, marital status, and psoriasis severity).

RESULTS

While RPL and LC models resulted in the same mean preference weights, different preference-heterogeneity patterns emerged from the two approaches. In both models, country of residence and self-reported disease severity could be linked to systematic differences in preferences. The RPL also identified gender and marital status, but not age, as sources of heterogeneity; the LC membership probability model indicated that age was a significant factor, but not gender or marital status.

CONCLUSIONS

Using data from a psoriasis patient survey to compare two widely used methods for exploring heterogeneity identified differences in results between stated-preferences: subgroup analysis in the RPL model and inclusion of subgroup characteristics in the class membership probability function of the LC model. Researchers should model data using the most adaptable approach to address the initial study question.

Survival and success of implants in a private periodontal practice: a 10 year retrospective study

BACKGROUND

To assess long-term results of implants (XiVE/Frialit-2 Synchro) in a private periodontal practice according to survival and success rates (biological and technical complications) and to detect possible influencing factors, retrospectively.

METHODS

Implant placement of at least one implant took place 10 years ±6 months before clinical and radiographic re-examination. Incidence of implant loss as main and incidence of mucositis/ peri-implantitis as secondary outcome were detected. Also, patient-related and implant-related influencing factors were determined by regression analyses.

RESULTS

100 patients (59.0% female) with 242 implants were included into analysis. Survival rate was 94.0% (XiVE: 97.7%; Frialit-2-Synchro: 66.7%). Mucositis was found in 77.6% of all patients, moderate/severe peri-implantitis in 16.3%. In logistic regression analyses statistically significant influencing factors for implant loss was implant type (p < 0.001), for mucositis a wider implant diameter (p = 0.0438) and a high modified Plaque Index (p = 0.0253), for peri-implantits number of implants per patient (p = 0.0075) and a wider implant diameter (p = 0.0079). Technical complications were found in 47 implants (19.4%).

CONCLUSIONS

XiVE implants showed a high survival rate over a 10-year follow-up, on the other hand Frialit-2 Synchro implants had worse survival rates. Success rates regarding biological complications are in line with other implant systems.

Combination of several matching adjusted indirect comparisons (MAICs) with an application in psoriasis

In health technology assessment (HTA), beside network meta-analysis (NMA), indirect comparisons (IC) have become an important tool used to provide evidence between two treatments when no head-to-head data are available. Researchers may use the adjusted indirect comparison based on the Bucher method (AIC) or the matching-adjusted indirect comparison (MAIC). While the Bucher method may provide biased results when included trials differ in baseline characteristics that influence the treatment outcome (treatment effect modifier), this issue may be addressed by applying the MAIC method if individual patient data (IPD) for at least one part of the AIC is available. Here, IPD is reweighted to match baseline characteristics and/or treatment effect modifiers of published data. However, the MAIC method does not provide a solution for situations when several common comparators are available. In these situations, assuming that the indirect comparison via the different common comparators is homogeneous, we propose merging these results by using meta-analysis methodology to provide a single, potentially more precise, treatment effect estimate. This paper introduces the method to combine several MAIC networks using classic meta-analysis techniques, it discusses the advantages and limitations of this approach, as well as demonstrates a practical application to combine several (M)AIC networks using data from Phase III psoriasis randomized control trials (RCT).

Diagnostic Value of the Basic Erosive Wear Examination for the Assessment of Dental Erosion on Patients, Dental Photographs, and Dental Casts

OBJECTIVES

The aim of this trial was to investigate the diagnostic value of the basic erosive wear examination (BEWE) in clinical use, on dental photographs, and on dental casts over a two-year follow-up period (2013-2015). According to the main hypothesis for longitudinal monitoring of dental erosion, the BEWE is equally reproducible by the three assessment methods.

METHODS AND MATERIALS

The clinical assessment included intraoral photographic documentation, dental impressions, oral examination, and assessment of BEWE. Clinical assessment of BEWE was done by one blinded examiner, whereas assessment on photographs and dental casts was performed by three calibrated examiners and repeated after 14 days. The three assessment methods were analyzed separately by longitudinal agreement and inter- and intrarater reliability (intraclass correlation coefficient) alongside 95% confidence intervals (CIs).

RESULTS

Comparing the longitudinal data of the years 2013-2015, clinical use and photographs showed no significant difference (p=0.0681-0.9963), whereas the statistical analysis showed a significant difference for dental casts by comparing data from 2013 vs 2014 (p=0.0266) as well as data from 2013 vs 2015 (p=0.0001). Statistical evaluation of overall BEWE showed an intrarater reliability of 0.79-0.91 for photographs and 0.60-0.87 for dental casts. The interrater reliability was 0.77 (95% CI=[0.69; 0.84]) for photographs and 0.63 (95% CI=[0.52; 0.72]) for dental casts.

CONCLUSION

This investigation showed that in longitudinal clinical monitoring, the assessment of the BEWE on patients and dental photographs yielded comparable results. In addition, based on these findings, the assessment of the BEWE on dental casts showed moderate reproducibility. Therefore, dental casts may be better used for laboratory assessment techniques.

Alternative Weighting Approaches for Anchored Matching-Adjusted Indirect Comparisons via a Common Comparator

BACKGROUND

Adjusted indirect comparisons (anchored via a common comparator) are an integral part of health technology assessment. These methods are challenged when differences between studies exist, including inclusion/exclusion criteria, outcome definitions, patient characteristics, as well as ensuring the choice of a common comparator.

OBJECTIVES

Matching-adjusted indirect comparison (MAIC) can address these challenges, but the appropriate application of MAICs is uncertain. Examples include whether to match between individual-level data and aggregate-level data studies separately for treatment arms or to combine the arms, which matching algorithm should be used, and whether to include the control treatment outcome and/or covariates present in individual-level data.

RESULTS

Results from seven matching approaches applied to a continuous outcome in six simulated scenarios demonstrated that when no effect modifiers were present, the matching methods were equivalent to the unmatched Bucher approach. When effect modifiers were present, matching methods (regardless of approach) outperformed the Bucher method. Matching on arms separately produced more precise estimates compared with matching on total moments, and for certain scenarios, matching including the control treatment outcome did not produce the expected effect size. The entropy balancing approach was used to determine whether there were any notable advantages over the method proposed by Signorovitch et al. When unmeasured effect modifiers were present, no approach was able to estimate the true treatment effect.

CONCLUSIONS

Compared with the Bucher approach (no matching), the MAICs examined demonstrated more accurate estimates, but further research is required to understand these methods across an array of situations.

Effects of staining and polishing on different types of enamel surface sealants

OBJECTIVE

To assess surface discoloration of four enamel sealants based on different chemical compositions after exposure to artificial aging and staining solutions. Furthermore, their cleanability after polishing will be evaluated.

MATERIALS AND METHODS

Selected sealants were a composite resin-based sealant with fillers (Pro Seal), a composite resin-based sealant without fillers (Light BondSealant), a resin-modified glass ionomer-based sealant (ClinproXT Varnish) and a silicon-based sealant (Protecto). Natural teeth served as medium. Immersion solutions were water, juice, tea, and turmeric. In a standardized setting, all samples were measured seven times with a spectroradiometer (Photoresearch PR670) at baseline, after thermocycling; 7 days; 2 and 4 weeks of immersion; and after finally polishing.

RESULTS

Thermocycling had no significant effect on color stability. After exposure to staining solutions, all sealed surfaces showed significant color changes. Color change predominately occurred for all sealants in the first week of staining (P ≤ .01). Best resistance to staining decreased as follows: Protecto > Light Bond Sealant > ProSeal > Clinpro XT Varnish. Surface cleaning by polishing significantly reduced the color change.

CONCLUSION

Sealed enamel surfaces are prone to discoloration, which is most prominent in filled composite and glass-ionomer-based sealants. Staining can be reduced by polishing; however, in this in vitro setting the original color could not be restored.

CLINICAL SIGNIFICANCE

Enamel sealants might exert adverse effects in terms of discoloration. This should be taken into consideration by clinicians and patients, particularly when sealants are applied in esthetically critical areas.

Psychosocial impact, perceived stress and learning effect in undergraduate dental students during transition from pre-clinical to clinical education

INTRODUCTION

This study aimed to develop a suitable instrument for a comprehensive quantitative and qualitative assessment of perceived psychosocial impact, levels of stress and learning effect in undergraduate dental students during the transition from pre-clinical to clinical education. These findings might improve curricular structures and didactic organisation during this period.

MATERIALS AND METHODS

At the beginning of their first clinical year, undergraduate dental students were asked to complete an anonymous forty-item questionnaire. Two hundred and seventy-six undergraduate dental students were willing to participate and completed the questionnaire and participated during the years 2011-2016.

RESULTS

The response rate was between 45% and 96%. Correlational analysis (Spearman-Rho) in the field of psychosocial impact showed the dental teacher to be the most important multiplier of students' feelings. If the students feel that their teacher acts cooperatively, positive items increase and negative items decrease significantly (P < .0001). Also, students who report high levels of stress are affected significantly in their psychosocial interaction (P < .0001). Wilcoxon test yielded highest levels of stress in endodontology during the first weeks (P < .0001). During the same period, the greatest learning increment was seen for diagnostics and caries excavation.

CONCLUSION

In conclusion, teaching of undergraduate dental students during the transition period from pre-clinical to clinical education can be positively influenced by a supportive learning environment and by specific chronological modifications in the curriculum. Students should start their clinical training with diagnostics, preventive dentistry and initial periodontal treatment. Due to high levels of perceived stress, endodontology should be introduced later in the clinical curriculum.

Matching-adjusted indirect comparison of efficacy in patients with moderate-to-severe plaque psoriasis treated with ixekizumab vs. secukinumab

BACKGROUND

Head-to-head randomized studies comparing ixekizumab and secukinumab in the treatment of psoriasis are not available.

OBJECTIVES

To assess efficacy and quality of life using matching-adjusted indirect comparisons for treatment with ixekizumab vs. secukinumab.

METHODS

Psoriasis Area and Severity Index (PASI) improvement of at least 75%, 90% and 100% and Dermatology Life Quality Index (DLQI) 0/1 response rates for approved dosages of ixekizumab (160 mg at Week 0, then 80 mg every two weeks for the first 12 weeks) and secukinumab (300 mg at Weeks 0, 1, 2, 3 and 4, then 300 mg every 4 weeks) treatment were compared using data from active (etanercept and ustekinumab) and placebo-controlled studies. Comparisons were made using the Bucher (BU) method and two modified versions of the Signorovitch (SG) method (SG total and SG separate). Subsequently, results based on active treatment common comparators were combined using generic inverse-variance meta-analysis.

RESULTS

In the meta-analysis of studies with active comparators, PASI 90 response rates were 12·7% [95% confidence interval (CI) 5·5-19·8, P = 0·0005], 10·0% (95% CI 2·1-18·0, P = 0·01) and 11·2% (95% CI 3·2-19·1, P = 0·006) higher and PASI 100 response rates were 11·7% (95% CI 5·9-17·5, P < 0·001), 12·7% (95% CI 6·0-19·4, P < 0·001) and 13·1% (95% CI 6·3-19·9, P < 0·001) higher for ixekizumab compared with secukinumab using BU, SG total and SG separate methods. PASI 75 results were comparable when SG methods were used and favoured ixekizumab when the BU method was used. Week 12 DLQI 0/1 response rates did not differ significantly.

CONCLUSIONS

Ixekizumab had higher PASI 90 and PASI 100 responses at week 12 compared with secukinumab using adjusted indirect comparisons.

Long-term stability of splinted anterior mandibular teeth during supportive periodontal therapy

OBJECTIVE

The aim of the study was to retrospectively assess the survival rate and stability of periodontally compromised and mobile anterior mandibular teeth after splinting in patients under supportive periodontal therapy (SPT).

MATERIALS AND METHODS

Thirty-nine patients with splinted anterior mandibular teeth and SPT (≥1 visit/year) for 3-15 years were re-examined. Periodontal status, patient and tooth-related factors were assessed retrospectively before (baseline) and 3 years after splinting (n = 39 patients, 162 splinted teeth). For patients with splints inserted for more than 3 years, retrospective data after 5 (n = 30), 7 (n = 24), 10 (n = 16), 12 (n = 8) and 15 years (n = 4) was included, if available. At baseline, splinted teeth included at least one tooth with increased mobility combined with clinical attachment loss (CAL) ≥ 5 mm and ≥50% relative bone loss (RBL). Baseline RBL of splinted teeth was assessed for all patients. Change in RBL was assessed after 10 years, if available.

RESULTS

No splinted tooth was lost within the first 3 years after splinting. One splinted tooth was lost 7 years after baseline and one 12 years after baseline. After 3 years mean(SD) periodontal probing depth of splinted teeth decreased from 3.39(1.41) mm to 2.12(0.37) mm and mean(SD) CAL from 5.61(1.66) mm to 5.09(1.67) mm and remained stable over the observation period. No change in RBL was observed over a 10-year period (p = .213). The survival rate of the splints until fracture or debonding was 74.4% after 3 years.

CONCLUSIONS

Periodontally compromised splinted teeth show a high survival-rate and periodontal stability during SPT.

Yield of active screening for tuberculosis among asylum seekers in Germany: a systematic review and meta-analysis

All asylum seekers in Germany undergo upon-entry screening for tuberculosis TB, but comprehensive evidence on the yield is lacking. We compared the national estimates with the international literature in a systematic review and meta-analysis of studies reporting the yield of TB, defined as the fraction of active TB cases detected among asylum seekers screened in Germany upon entry. We searched 11 national and international databases for empirical studies and the internet for grey literature published in English or German without restrictions on publication time. Among 1,253 screened articles, we identified six articles reporting the yield of active TB based on German data, ranging from 0.72 (95% confidence interval (CI): 0.45-1.10) to 6.41 (95% CI: 4.19-9.37) per 1,000 asylum seekers. The pooled estimate across all studies was 3.47 (95% CI: 1.78-5.73; I2 = 94.9%; p < 0.0001) per 1,000 asylum seekers. This estimate was in line with international evidence (I2 = 0%; p for heterogeneity 0.55). The meta-analysis of available international estimates resulted in a pooled yield of 3.04 (95% CI: 2.24-3.96) per 1,000. This study provides an estimate across several German federal states for the yield of TB screening in asylum seekers. Further research is needed to develop more targeted screening programmes.

[Systematic review and evidence mapping of empirical studies on health status and medical care among refugees and asylum seekers in Germany (1990-2014)]

BACKGROUND

Owing to a lack of routine statistics on the health status and medical care of asylum seekers, empirical studies play a major role in the mapping of these aspects.

OBJECTIVES

The aim of this review is to provide a comprehensive overview of the research landscape in this area, synthesizing knowledge from empirical studies and identifying evidence gaps.

METHODS

A three-tiered search strategy included searching for empirical studies in national/international databases and on the internet, screening reference lists, and contacting experts. Studies meeting predefined inclusion criteria were thematically organized and described in a narrative synthesis.

RESULTS

The searches generated 1,190 hits; 52 articles met the inclusion criteria. Of these, 41 were quantitative studies (78.9 %), 10 qualitative (19.2 %), and 1 was a review (1.9 %). A total of 30 primary articles (58.9 %) analyzed mental health aspects, followed by infectious diseases (n = 12, 23.5 %). Qualitative studies, mainly ethnographies and case studies, explored mental health and social determinants of health, providing evidence for the impact of living conditions on health and medical care. Few studies analyzed chronic diseases (n = 3) or childhood illnesses (n = 6). No studies analyzed the health needs or medical care of asylum-seeking women during pregnancy and child birth. In 62.7 % of the primary studies, a single sampling point was used to recruit asylum seekers. Nationwide external validity was given in two quantitative studies.

CONCLUSION

The priority research areas identified are chronic diseases and childhood and maternal health. The divergency and heterogeneity of the studies hamper a comprehensive and comparable acquisition of knowledgeand emphasize the  need for collaborative research to close the existing evidence gaps.

START NOW - a comprehensive skills training programme for female adolescents with oppositional defiant and conduct disorders: study protocol for a cluster-randomised controlled trial

Background

In Europe, the number of females exhibiting oppositional defiant disorder (ODD) and conduct disorder (CD) is growing. Many of these females live in youth welfare institutions. Consequently, there is a great need for evidence-based interventions within youth welfare settings. A recently developed approach targeting the specific needs of girls with ODD and CD in residential care is START NOW. The aim of this group-based behavioural skills training programme is to specifically enhance emotional regulation capacities to enable females with CD or ODD to appropriately deal with daily-life demands. It is intended to enhance psychosocial adjustment and well-being as well as reduce oppositional and aggressive behaviour. We present the study protocol (version 4.1; 10 February 2016) of the FemNAT-CD intervention trial titled ‘Group-Based Treatment of Adolescent Female Conduct Disorders: The Central Role of Emotion Regulation’.

Methods/design

The study is a prospective, confirmatory, cluster-randomised, parallel-group, multi-centre, randomised controlled trial with 128 institutionalised female adolescents who fulfil the diagnostic criteria of ODD and/or CD. Institutions/wards will be randomised either to provide the 12-week skills training as an add-on intervention or to provide treatment as usual. Once the first cycle is completed, each institution will run a second cycle with the opposite condition. Primary endpoints are the pre-post change in number of CD/ODD symptoms as assessed by a standardised, semi-structured psychiatric interview (Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children–Present and Lifetime, CD/ODD section) between baseline and the end of intervention, as well as between baseline and a 3-month follow-up point. Secondary objectives include pre-post change in CD/ODD-related outcome measures, most notably emotional regulation on a behavioural and neurobiological level after completion of START NOW compared with treatment as usual.

Discussion

To our knowledge, this study is the first to date to systematically investigate the effectiveness of an adapted integrative psychosocial intervention designed for female adolescents with ODD and CD in youth welfare settings.

Trial registration

German Clinical Trials Register (DRKS) identifier: DRKS00007524. Registered on 18 December 2015 and with the World Health Organisation International Clinical Trials Registry Platform.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1705-6) contains supplementary material, which is available to authorized users.

The prognostic effect of cardiac rehabilitation in the era of acute revascularisation and statin therapy: A systematic review and meta-analysis of randomized and non-randomized studies - The Cardiac Rehabilitation Outcome Study (CROS)

Background

The prognostic effect of multi-component cardiac rehabilitation (CR) in the modern era of statins and acute revascularisation remains controversial. Focusing on actual clinical practice, the aim was to evaluate the effect of CR on total mortality and other clinical endpoints after an acute coronary event.

Design

Structured review and meta-analysis.

Methods

Randomised controlled trials (RCTs), retrospective controlled cohort studies (rCCSs) and prospective controlled cohort studies (pCCSs) evaluating patients after acute coronary syndrome (ACS), coronary artery bypass grafting (CABG) or mixed populations with coronary artery disease (CAD) were included, provided the index event was in 1995 or later.

Results

Out of n = 18,534 abstracts, 25 studies were identified for final evaluation (RCT: n = 1; pCCS: n = 7; rCCS: n = 17), including n = 219,702 patients (after ACS: n = 46,338; after CABG: n = 14,583; mixed populations: n = 158,781; mean follow-up: 40 months). Heterogeneity in design, biometrical assessment of results and potential confounders was evident. CCSs evaluating ACS patients showed a significantly reduced mortality for CR participants (pCCS: hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.20–0.69; rCCS: HR 0.64, 95% CI 0.49–0.84; odds ratio 0.20, 95% CI 0.08–0.48), but the single RCT fulfilling Cardiac Rehabilitation Outcome Study (CROS) inclusion criteria showed neutral results. CR participation was also associated with reduced mortality after CABG (rCCS: HR 0.62, 95% CI 0.54–0.70) and in mixed CAD populations.

Conclusions

CR participation after ACS and CABG is associated with reduced mortality even in the modern era of CAD treatment. However, the heterogeneity of study designs and CR programmes highlights the need for defining internationally accepted standards in CR delivery and scientific evaluation.

Endodontic status and retention of molars in periodontally treated patients: results after 10 or more years of supportive periodontal therapy

OBJECTIVES

To assess the influence of endodontic status on retention of molars in patients under supportive periodontal treatment (SPT).

MATERIAL & METHODS

A total of 136 subjects with 1015 molars at baseline were examined retrospectively, including 188 endodontically treated molars in 90 patients. Multilevel Cox regression analysis identified factors contributing to loss of molars.

RESULTS

Root canal treatments contributed significantly to loss of molars during on average 13.2 years of SPT (Hazard ratio: 2.98, 95% CI: 1.74-5.1, p < 0.001). Endodontic treatment was more frequently present in first molars (p < 0.001) and in the maxilla (p = 0.01). In endodontically treated molars, degree III furcation involvement could be detected more often compared to molars without root canal treatment (p < 0.001). Among the root canal-treated molars, several patient and tooth-related factors showed an impact on tooth retention, but only molars with a periapical index of 4 and 5 (labelled "diseased") were significantly more often lost.

CONCLUSION

The retention of molars in periodontally compromised patients after periodontal treatment is influenced by periodontal as well as endodontal factors. On a long-term basis, it is feasible to retain these teeth via active periodontal treatment and SPT for more than 10 years.

In vitro evaluation of different dental materials used for the treatment of extensive cervical root defects using human periodontal cells

INTRODUCTION

Repair materials for extensive cervical root defects may come in direct contact with periodontal tissues. This in vitro study compared the effects of four calcium silicate cements (CSC), one resin-modified glass ionomer cement, and one glass carbomer cement on primary human gingival fibroblasts (HGF), alveolar osteoblasts (HAO), and a human osteoblast cell line (hFOB 1.19).

METHODS

HGF, HAO, and hFOB were seeded on discoid test specimens. Relative numbers of viable cells were quantitatively assessed after 1 and 24 h for cytotoxicity/adhesion assays and after 4, 24, 48, and 72 h for proliferation assays. Data were statistically analyzed using non-parametric tests (α = 0.05).

RESULTS

Relative to the control (100 %), CSC allowed for mean numbers of 71-81 % viable HGF and 80-82 % viable HAO. Then, 64 % of HGF and 56 % of HAO were assessed on GC Fuji II LC. Mean numbers of viable cells were 59-64 % HGF and 67-68 % HAO for GCP Glass Fill specimens. Cells exposed to CSC over 24 h remained viable and even increased in number. Both cell types adhered almost equally well to CSC and GC Fuji II LC. GCP Glass Fill continued to decrease cell viability and adhesion. CSC-based materials and GC Fuji II LC allowed for HGF and hFOB proliferation; however, none of the tested materials specifically stimulated cell proliferation.

CONCLUSIONS

CSC characterized by low cytotoxicity. GC Fuji II LC shows moderate cytotoxic effects. ProRoot MTA, Harvard MTA, Biodentine, EndoSequence putty, and GC Fuji II LC allow HGF and HAO to adhere and HGF and hFOB to proliferate. GCP Glass Fill decreases cell viability, adhesion, and proliferation.

CLINICAL RELEVANCE

CSC remain the paramount biologic choice for the repair of extensive cervical root defects. GC Fuji II LC might be considered in addition to CSC when the defect comprises supracrestal areas and the restoration requires superior aesthetic and mechanical characteristics.

Loss of molars in periodontally treated patients: results 10 years and more after active periodontal therapy

AIM

To identify risk factors for loss of molars during supportive periodontal therapy (SPT).

MATERIALS AND METHODS

A total of 136 subjects with 1015 molars at baseline were examined retrospectively. The association of risk factors with loss of molars was assessed using a multilevel Cox regression analysis. Furcation involvement (FI) was assessed clinically at start of periodontal therapy and assigned according to Hamp et al. (1975).

RESULTS

Fifty molars were extracted during active periodontal therapy (APT) and 154 molars over the average SPT period of 13.2 ± 2.8 years. FI degree III (HR 4.68, p < 0.001), baseline bone loss (BL) > 60% (HR 3.74, p = 0.009), residual mean probing pocket depth (PPD, HR 1.43, p = 0.027), and endodontic treatment (HR 2.98, p < 0.001) were identified as relevant tooth-related factors for loss of molars during SPT. However, mean survival time for molars with FI III or BL > 60% were 11.8 and 14.4 years, respectively. Among the patient data, age (HR 1.57, p = 0.01), female gender (HR 1.99, p = 0.035), smoking (HR 1.97, p = 0.034), and diabetes mellitus (HR 5.25, p = 0.021) were significant predictors for loss of molars.

CONCLUSION

Overall, periodontal therapy results in a good prognosis of molars. Degree III FI, progressive BL, endodontic treatment, residual PPD, age, female gender, smoking, and diabetes mellitus strongly influence the prognosis for molars after APT.

A Prospective Clinical Pilot Study on the Level of Matrix Metalloproteinase-9 in Dental Pulpal Blood as a Marker for the State of Inflammation in the Pulp Tissue

INTRODUCTION

Differentiation between reversible pulpitis (savable pulp) and irreversible inflammation of the pulp tissue (nonsavable pulp) based only on clinical and radiographic diagnoses has proven to be difficult. Pulp exposure allows for the collection of pulpal blood to quantitatively determine the level of inflammation markers or proteolytic enzymes, even with small samples. Pulpitis is associated with the invasion of neutrophil granulocytes and their release of matrix metalloproteinase-9 (MMP-9).

METHODS

Forty-four patients (aged 18-74 years, mean = 35 years), each with 1 tooth with carious pulp exposure presenting with different stages of pulpitis, were included in this prospective, 2-center clinical study; 26 patients presented with irreversible pulpitis (groups 3 and 4), 10 with reversible pulpitis (group 2), and 8 with completely asymptomatic teeth with deep carious lesions (group 1). Six of the 26 patients with teeth diagnosed with irreversible pulpitis had not taken any nonsteroidal anti-inflammatory drugs and were evaluated as a separate group (group 4). Partial pulpotomy and blood sample collection from the pulp chamber were performed. The total levels of MMP-9 and tissue inhibitor of metalloproteinase-1 were assessed by fluorometric and colorimetric enzyme-linked immunosorbent assays, respectively. The Mann-Whitney U test and Spearman rank correlations were used to compare the MMP-9 levels with different stages of pulpal inflammation; significance was set at .05.

RESULTS

The MMP-9 levels in the asymptomatic teeth (group 1) were significantly different from those in the teeth with reversible pulpitis (group 2, P = .006) or irreversible pulpitis (group 4, P < .001). A statistically significant difference was also observed between the MMP-9 levels in group 1 and group 3 (P < .001) in which the patients had taken nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

These findings indicate that the MMP-9 levels in pulpal blood samples could be a useful ancillary diagnostic tool for distinguishing different stages of pulp tissue inflammation.

Peripheral blood natural killer cell percentages in granulomatosis with polyangiitis correlate with disease inactivity and stage

Introduction

The role of CD3−CD56+ natural killer (NK) cells in granulomatosis with polyangiitis (GPA) is poorly understood. Recently, it has been shown that peripheral blood NK cells can kill renal microvascular endothelial cells, suggesting a pathogenic role of NK cells in this disease. So far, subset distribution, phenotype, and function of peripheral blood NK cells in relation to GPA disease activity have not been elucidated. Moreover, it is not known whether NK cells infiltrate GPA tissue lesions.

Methods

Paraffin sections of GPA granulomas and controls were stained with anti-CD56 and anti-CD3 antibodies. Peripheral blood lymphocyte subsets were analyzed by flow cytometry. NK cell degranulation was analyzed using cocultures of patient PBMCs with target cells and surface expression of CD107a. Clinical data were extracted from medical records. Statistical analysis was performed in an exploratory way.

Results

CD56+ cells were not detectable in active granulomatous GPA lesions but were found frequently in granulomas from tuberculosis and sarcoidosis patients. In GPA, the proportion of NK cells among peripheral blood lymphocytes correlated negatively with the Birmingham Vasculitis Activity Score (BVAS) (n = 28). Accordingly, NK cell percentages correlated positively with the duration of remission (n = 28) and were significantly higher in inactive GPA (BVAS = 0, n = 17) than in active GPA, healthy controls (n = 29), and inactive control diseases (n = 12). The highest NK cell percentages were found in patients with long-term remission and tapered immunosuppressive therapy. NK cell percentages >18.5 % of peripheral blood lymphocytes (n = 12/28) determined GPA inactivity with a specificity of 100 %. The differentiation into CD56^dim and CD56^bright NK cell subsets was unchanged in GPA (n = 28), irrespective of disease activity. Similar surface expression of the activating NK cell-receptors (NKp30, NKp46, and NKG2D) was determined. Like in healthy controls, GPA NK cells degranulated in the presence of NK cell receptor ligand bearing epithelial and lymphatic target cells.

Conclusions

NK cells were not detectable in GPA granulomas. Peripheral blood NK cell percentages positively correlate with the suppression of GPA activity and could serve as a biomarker for GPA activity. Peripheral blood NK cells in GPA patients are mature NK cells with preserved immune recognition.

[Influence of corneal pachymetric changes on functional results after cataract surgery]

BACKGROUND

In the early postoperative period following uncomplicated cataract surgery, the correlation of corrected distance visual acuity (CDVA) and the increase in corneal thickness and anterior chamber depth (ACD) are investigated.

PATIENTS AND METHODS

A total of 54 cataract patients with a mean age of 70 ± 8.4 years were included in this prospective study. Surgery was carried out on one eye of each patient according to the study protocol. Refraction, CDVA and ACD were evaluated 1 day and 1 week postoperatively and compared with the pachymetry results measured with the Pentacam.

RESULTS

The mean postoperative CDVA significantly improved from 0.31 ± 0.24 logMAR to 0.18 ± 0.22 logMAR after one day and up to 0.06 ± 0.13 logMAR one week after surgery (p < 0.05). The mean spherical equivalent was - 0.52 ± 0.69 D after one day and - 0.50 ± 0.82 D one week after surgery and showed only minimal differences compared to the mean target refraction of - 0.39 ± 0.70 D. Postoperative corneal thickness showed a significant increase compared to the preoperative results (p < 0.05) on both visits: the mean difference was 33.26 ± 50.20 µm (- 17 to 315 µm) on the first day and 20.22 ± 23.15 µm (- 10 to 99 µm) one week after surgery. Up to 7 days postoperatively the increase in corneal thickness and CDVA showed only moderate or no correlations (r = 0.465 vs. r = 0.072, respectively). Regarding pachymetry and ACD values, no or only low correlations were found.

CONCLUSION

The significant increase in corneal thickness on the first and seventh day shows no to moderate correlation to the CDVA. Nevertheless, a good and early rehabilitation of visual acuity following uncomplicated cataract surgery is possible. Intraocular pressure measurement can lead to false high results due to an increase in corneal thickness.

Closed cannulation of subclavian vein vs open cut-down of cephalic vein for totally implantable venous access port (TIVAP) implantation: protocol for a systematic review and proportional meta-analysis of perioperative and postoperative complications

BACKGROUND

Totally implantable venous access port (TIVAP) implantation is one of the most often performed operations in general surgery (over 100,000/year in Germany). The two main approaches for TIVAP placement are insertion into the cephalic vein through an open cut-down technique (OCD) or closed cannulation technique of the subclavian vein (CC) with Seldinger technique. Both procedures are performed with high success rates and very low complication frequencies. Because of the low incidence of complications, no single interventional trial is able to report a valid comparison of peri- and postoperative complication frequencies between both techniques. Therefore, the aim of this systematic review is to summarize evidence for peri- and postoperative complication rates in patients undergoing OCD or CC.

METHODS/DESIGN

A systematic literature search will be conducted in The Cochrane Library, MEDLINE, and Embase to identify randomized controlled trials (RCTs), observational clinical studies (OCS), or case series (CS) reporting peri- and/or postoperative complications of at least one implantation technique. A priori defined data will be extracted from included studies, and methodological quality will be assessed. Event rates with their 95% confidence intervals will be derived taking into account the follow-up time per study by patient-months where appropriate. Pooled estimates of event rates with corresponding 95% confidence intervals will be calculated on the base of the Freeman-Tukey double arcsine transformation within a random effect model framework.

DISCUSSION

The findings of this systematic review with proportional meta-analysis will help to identify the procedure with the best benefit/risk ratio for TIVAP implantation. This may have influence on daily practice, and data may be implemented in treatment guidelines. Considering the impact of TIVAP implantation on patients' well being together with its socioeconomic relevance, patients will benefit from evidence-based treatment and health-care costs may also be reduced.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42013005180.

Hand suture versus stapler for closure of loop ileostomy--a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The aims of this study are to compare the 30-day rate of bowel obstruction for stapled vs. handsewn closure of loop ileostomy, and to further assess efficacy and safety for each technique by secondary endpoints such as operative time, rates of anastomotic leakage, and other post-operative complications within 30 days.

METHODS

A systematic literature search (MEDLINE, The Cochrane Library, EMBASE and ISI Web of Science) was performed to identify randomized controlled trials (RCTs) comparing stapled and handsewn closure of loop ileostomy after low anterior resection. Random effects meta-analyses were calculated and presented as risk ratio (RR) and mean difference (MD) with corresponding 95 % confidence intervals.

RESULTS

Forty publications were retrieved and 4 RCTs (649 patients) were included. There was methodological and clinical heterogeneity of included trials, but statistical heterogeneity was low for most endpoints. Stapler use significantly reduced the rate of bowel obstruction compared to hand-sewn closure (RR 0.53 [0.32, 0.88]; P = 0.01). The operation time was significantly lower for stapling compared to hand suture (MD -15.5 min [-18.4, 12.6]; P < 0.001). All other secondary outcomes did not show significant differences.

CONCLUSIONS

This meta-analysis shows superiority of stapled closure of loop ileostomy compared to handsewn closure in terms of bowel obstruction rate and mean operation time. Other relevant complications such as anastomotic leakage are equivalent. Even so, both techniques are options with opposing advantages and disadvantages.

In vitro studies on the cytotoxic potential of surface sealants

OBJECTIVE

The objective of this in vitro study was an initial screening of the cytotoxic potential of widely used smooth enamel surface sealants.

MATERIALS AND METHODS

A total of 20 products were allocated to four groups based on their chemical composition: (1) filled resin-based sealants, (2) unfilled resin-based sealants, (3) a resin-modified, glass ionomer-based sealant, and (4) silicone-based sealants. All materials were applied to human enamel slices both in accordance with manufacturers' instructions and in additional experiments applying 50% undercuring and 50% overcuring. An agar overlay assay was then used to test the specimens following ISO 10933. The cytotoxic potential of each material was interpreted based on a reaction index that summarized the decolorization and lysis scores obtained.

RESULTS

The cytotoxic potential decreased as follows: unfilled resin-based sealants > filled resin-based sealants > resin-modified, glass ionomer-based sealant > silicone-based sealants. In 75% of the resin-based products, deliberate undercuring was associated with more extensive decolorization zones, leading to higher rates of cytotoxic potential in two of those products. Overcuring, by contrast, was associated with a tendency for smaller decolorization zones in 50% of the resin-based products.

CONCLUSION

Surface sealants derived from resin monomers exhibited cytotoxic potential in the agar overlay assay. There is also evidence of a possible association with curing, as undercuring can increase the cytotoxic potential, whereas normal curing (as per manufacturers' instructions) or overcuring may help minimize such effects. More research into the biological implications of these materials is needed, especially with regard to their potential impact on the adjacent gingiva.