New design of interdental rubber picks - does the archimedean screw design bring an improvement for experimental cleaning efficacy and force?

BACKGROUND

Up to date, interdental brushes (IDB) are the first choice for interdental cleaning because of their cleaning efficacy. Cylindrical ones must be selected individually according to the size/morphology of the interdental area (IDR), whereas conical ones cover a larger variability of IDR. However, there is a trend on the part of patients towards interdental rubber picks (IRP) which are in general conically shaped, and which seem to be linked with lower cleaning efficacy. A new IRP with an Archimedes´ screw design was developed to overcome this limitation. Therefore, the in vitro study aimed to measure the experimental cleaning efficacy (ECE) and force (ECF) during interdental use of IDBs versus the new IRP type.

METHODS

Three IRPs with different tapers (PHB angled: 0.039, PHB straight S: 0.027, Vitis straight M: 0.045; all Flexipicks, Dentaid, Cerdanyola del Vallès, Spain) were compared to one IDB (Interprox micro PHD 0.9, Dentaid, Cerdanyola del Vallès, Spain). IDR were reproduced by a 3D-printer (Form2, Formlabs Sommerville, MA, USA) according to human teeth and matched to equivalent pairs (isosceles triangle, concave, convex) in three different diameters (1.0 mm,1.1 mm,1.3 mm). Covered with simulated biofilm, pre-/ post-brushing situations of IDR (standardized, computer-aided ten cycles) were photographed and quantified by digital image subtraction to calculate ECE [%]. ECF were registered with a load cell [N]. Statistically significant differences were detected using the Mann-Whitney-U-test and the Kruskal-Wallis-test with Bonferroni correction for multiple testing.

RESULTS

Overall, the ECE (mean ± SD) was higher for IDB micro 0.9 (45.95 ± 11.34%, p < 0.001) compared to all IRPs (PHB angled: 25.37 ± 15.29%; PHB straight: 22.28 ± 16.75%; Vitis straight: 25.24 ± 12.21%; p ≤ 0.001), whereat best ECE was achieved in isosceles triangle IDR of 1.0-1.1 mm (IDB micro 0.9: 70.7 ± 7.7%; PHB angled S: 57.30 ± 4.43%; p < 0.001). The highest ECF occurred for Vitis straight M with 2.11 ± 0.46 N, while IDB micro 0.9 showed lowest ECF values (0.64 ± 0.14 N; p < 0.001).

CONCLUSIONS

IRP with an Archimedes´ screw design and a higher taper were associated with advanced ECE but also higher ECF, nevertheless, ECE didn't reach the cleaning efficacy of conventional IDBs.

Long-term effect of simulated five years professional mechanical biofilm removal on the luting gap of ceramic restorations

BACKGROUND

Achieving sufficient professional mechanical biofilm removal (PMPR) can be challenging in supportive periodontal therapy (SPT), particularly in patients with prosthetic restorations. This experimental study aimed to simulate five years of SPT with periodic PMPR near the luting gap of ceramic restorations using a rubber cup with polishing paste (RCP), air polishing with two different low-abrasive powders (LAPA-1: glycine powder, LAPA-2: erythritol powder), and non-professional mechanical cleaning (control group) to measure the extent of volume loss in the luting gap after baseline (∆V = Vbaseline-V1-5; in µm3).

METHODS

Two operators randomly performed PMPR ten times for thirty seconds on one of four sides of 30 crown replicas fixed with glass-ionomer cement (CGIZ: n = 15) or adhesive bonding (CAB: n = 15). The replicas were separated in a template during PMPR, and afterward, cleaned for five seconds per side with a sonic brush under flowing water. The artificial aging process between two PMPRs simulated a 5-year SPT with two PMPRs per year. Profilometric measurements were performed at baseline and after each second PMPR to obtain the mean change of ∆V. The statistical evaluation of the data was carried out using nonparametric tests with Bonferroni correction applied for multiple tests.

RESULTS

Ninety-six out of 120 sides could be included in the analysis. PMPR methods showed a loss of substance in the luting gap with a ∆V (mean(standard deviation)) of -4.35 × 106(4.8 × 106)µm3 versus 8.79 × 104(1.05 × 106)µm3 for control at V5 (p ≤ 0.001). No significant differences of ∆V1-5 values could be identified in the control (p > 0.05), whereat all PMPRs showed a significant increasing loss of substance per simulated year (p ≤ 0.001). Intergroup comparison identified LAPA-1 as having the highest significant loss of substance determined on CAB (∆V: -1.05 × 107 (7,2 × 106) µm3), followed by LAPA-2 on CAB (∆V: -6.29 × 106 (4,24 × 106) µm3), LAPA-1 on CGIZ (∆V: -4.15 × 106 (3,25 × 106) µm3), LAPA-2 on CGIZ (∆V: -3.0 × 106 (2,23 × 106) µm3), RCP on CAB (∆V: -1.86 × 106 (2,23 × 106) µm3) and CGIZ (∆V: -1.2 × 106 (1,31 × 106) µm3; p ≤ 0.001)).

CONCLUSIONS

Within study limitations, all PMPRs caused a significantly higher loss of substance in the luting gap versus control without professional intervention, with the highest values in the CAB group for LAPA-1, LAPA-2 and RCP. Similar findings were observed for CGIZ, although the loss values were lower.

Toll-like receptor expression profile of stem/progenitor cells from human exfoliated deciduous teeth

BACKGROUND

Stem/progenitor cells from human exfoliated deciduous teeth (SHED) show remarkable pluripotent, regenerative, and immunological capacities. During in vivo regenerative processes, there could be the presence of SHED in the surrounding inflammatory microenvironment, through toll-like receptors (TLRs).

AIM

The aim of this paper was to present a characteristic TLR expression profile on SHED for the first time.

DESIGN

Cells were harvested from extracted primary teeth (n = 10), anti-STRO-1 immunomagnetically sorted and cultivated, through colony-forming units (CFUs). SHED were examined for mesenchymal stem/progenitor cell traits, including the expression of clusters of differentiation (CDs) 14, 34, 45, 73, 90, 105, and 146, and their multilineage differentiation aptitude. TLRs 1-10 expression was investigated for SHED in uninflamed and inflamed (25 ng/mL IL-1β, 103 U/mL IFN-γ, 50 ng/mL TNF-α, and 3 × 103  U/mL IFN-α; SHED-i) microenvironmental conditions.

RESULTS

SHED were negative for CDs 14, 34, and 45, but were positive for CDs 73, 90, 105, and 146, and demonstrated characteristic multilineage differentiation. In an uninflamed microenvironment, SHED expressed TLRs 1, 2, 3, 4, 6, 8, 9, and 10. The inflammatory microenvironment downregulated TLR7 significantly on gene level and upregulated TLR8 on gene and protein levels (p < .05; Wilcoxon signed-rank test).

CONCLUSION

There appears to be a unique TLR expression profile on SHED, which could modulate their immunological and regenerative abilities in oral tissue engineering approaches.

Polymeric Nanocomposite Hydrogel Scaffolds in Craniofacial Bone Regeneration: A Comprehensive Review

Nanocomposite biomaterials combine a biopolymeric matrix structure with nanoscale fillers. These bioactive and easily resorbable nanocomposites have been broadly divided into three groups, namely natural, synthetic or composite, based on the polymeric origin. Preparing such nanocomposite structures in the form of hydrogels can create a three-dimensional natural hydrophilic atmosphere pivotal for cell survival and new tissue formation. Thus, hydrogel-based cell distribution and drug administration have evolved as possible options for bone tissue engineering and regeneration. In this context, nanogels or nanohydrogels, created by cross-linking three-dimensional polymer networks, either physically or chemically, with high biocompatibility and mechanical properties were introduced as promising drug delivery systems. The present review highlights the potential of hydrogels and nanopolymers in the field of craniofacial tissue engineering and bone regeneration.

The influence of artificial saliva on the cleaning force of interdental rubber picks: an in-vitro comparison

BACKGROUND

The familiar aids for interdental cleaning such as dental floss or interdental brushes (IDB) are often associated with difficult handling or an increased potential for trauma. Interdental picks (IRP), which have no metal core and silicone flaps instead of nylon brushes, offer the alternative. However, in-vitro studies found a lower cleaning effectiveness combined with higher forces for cleaning compared with conventional IDBs. The aim of this in-vitro study was to measure the experimental cleaning forces (ECF) using IRP with versus without an artificial saliva (AS; GUM Hydral, Sunstar Suisse SA, Etoy, Switzerland).

METHODS

The test set-up was developed to investigate the cleaning of 3D-printed interdental area (IDR) mimicking human teeth (Form 2, Formlabs Sommerville, MA, USA) under standardized conditions. Three different morphologies (isosceles triangle, convex, concave) and three different sizes (1.0 mm,1.1 mm,1.3 mm) were used. Two different IRPs (GUM Soft-picks Advanced: SPA versus GUM Soft-picks Advanced Plus: SPA+, Sunstar Suisse SA, Etoy, Switzerland) in three sizes (small, regular, large), were used with versus without AS. ECF during ten cleaning cycles were recorded by a load cell [N].

RESULTS

Using AS leaded to significant lower values for ECF than without (1.04 ± 0.66 N versus 1.97 ± 1.01 N, p < 0.001). In general, a lower ECF was recorded for convex IDR compared to isosceles triangle and concave morphologies (p < 0.001) as well as for gap sizes of 1.3 mm compared to the smaller sizes (p < 0.001). For SPA+ we found significantly higher force values than for SPA (1.67 ± 0.93 N versus 1.31 ± 0.97 N, p < 0.001) independent of the use of AS.

CONCLUSION

Within the study´s in-vitro limitations, we found AS reduced ECF of IRPs by half and allowed using larger diameters interdentally, which could be associated with (1) a higher cleaning effectiveness and (2) a higher acceptance e.g. of patients with dry mouth. This has to be confirmed by further clinical investigations.

2D radiographs, cone-beam computed tomography and 3D CBCT-based planning software in access cavity preparation: A single blinded randomised controlled in vitro study

This study compared endodontic access cavities prepared by operators of different experience levels (students, general-practitioners and specialists), guided by periapical radiographs, cone-beam computed tomography (CBCT) or 3D CBCT-based planning software, with regards to tooth substance loss and preparation errors. Operators (n = 34) prepared endodontic access cavities in 306 three-dimensionally printed copies of human teeth with standardised anatomies. Access cavities were volumetrically assessed post-operative using digital scans, while preparation errors were evaluated with CBCT. Tooth substance loss was significantly influenced by the operator's experience, being highest with students', followed by general-practitioners and specialists (P < 0.05), with no significant association with the employed imaging/planning modality. Pulp chamber floor, iatrogenic perforations and incomplete pulpal roof removal were insignificant between operator groups or imaging/planning modalities. It can be concluded that irrespective of advancement in imaging/planning modalities the practitioner's experience level remains to be the decisive factor significantly influencing tooth substance loss during endodontic access cavity preparations.

Vitamin C and Omega-3 Fatty Acid Intake Is Associated with Human Periodontitis-A Nested Case-Control Study

Vitamins and omega-3 fatty acids (Ω3FA) modulate periodontitis-associated inflammatory processes. The aim of the current investigation was to evaluate associations of oral nutrient intake and corresponding serum metabolites with clinical severity of human periodontitis. Within the Food Chain Plus cohort, 373 periodontitis patients—245 without (POL) and 128 with tooth loss (PWL)—were matched to 373 controls based on sex, smoking habit, age and body mass index in a nested case-control design. The amount of oral intake of vitamins and Ω3FAs was assessed from nutritional data using a Food Frequency Questionnaire. Oral intake and circulatory bioavailability of vitamins and Ω3FA serum metabolomics were compared, using ultra-high-resolution mass spectrometry. Periodontitis patients exhibited a significantly higher oral intake of vitamin C and Ω3FA Docosapentaenoic acid (p < 0.05) compared to controls. Nutritional intake of vitamin C was higher in PWL, while the intake of Docosapentaenoic acid was increased in POL (p < 0.05) compared to controls. In accordance, serum levels of Docosapentaenoic acid were also increased in POL (p < 0.01) compared to controls. Vitamin C and the Ω3FA Docosapentaenoic acid might play a role in the pathophysiology of human periodontitis. Further studies on individualized nutritional intake and periodontitis progression and therapy are necessary.

Ascorbic Acid/Retinol and/or Inflammatory Stimuli's Effect on Proliferation/Differentiation Properties and Transcriptomics of Gingival Stem/Progenitor Cells

The present study explored the effects of ascorbic-acid (AA)/retinol and timed inflammation on the stemness, the regenerative potential, and the transcriptomics profile of gingival mesenchymal stem/progenitor cells' (G-MSCs). STRO-1 (mesenchymal stem cell marker) immuno-magnetically sorted G-MSCs were cultured in basic medium (control group), in basic medium with IL-1β (1 ng/mL), TNF-α (10 ng/mL) and IFN-γ (100 ng/mL, inflammatory-medium), in basic medium with AA (250 µmol/L) and retinol (20 µmol/L) (AA/retinol group) or in inflammatory medium with AA/retinol (inflammatory/AA/retinol group; n = 5/group). The intracellular levels of phosphorylated and total β-Catenin at 1 h, the expression of stemness genes over 7 days, the number of colony-forming units (CFUs) as well as the cellular proliferation aptitude over 14 days, and the G-MSCs' multilineage differentiation potential were assessed. Next-generation sequencing was undertaken to elaborate on up-/downregulated genes and altered intracellular pathways. G-MSCs demonstrated all mesenchymal stem/progenitor cells characteristics. Controlled inflammation with AA/retinol significantly elevated NANOG (p < 0.05). The AA/retinol-mediated reduction in intracellular phosphorylated β-Catenin was restored through the effect of controlled inflammation (p < 0.05). Cellular proliferation was highest in the AA/retinol group (p < 0.05). AA/retinol counteracted the inflammation-mediated reduction in G-MSCs' clonogenic ability and CFUs. Amplified chondrogenic differentiation was observed in the inflammatory/AA/retinol group. At 1 and 3 days, the differentially expressed genes were associated with development, proliferation, and migration (FOS, EGR1, SGK1, CXCL5, SIPA1L2, TFPI2, KRATP1-5), survival (EGR1, SGK1, TMEM132A), differentiation and mineral absorption (FOS, EGR1, MT1E, KRTAP1-5, ASNS, PSAT1), inflammation and MHC-II antigen processing (PER1, CTSS, CD74) and intracellular pathway activation (FKBP5, ZNF404). Less as well as more genes were activated the longer the G-MSCs remained in the inflammatory medium or AA/retinol, respectively. Combined, current results point at possibly interesting interactions between controlled inflammation or AA/retinol affecting stemness, proliferation, and differentiation attributes of G-MSCs.

Effect of Polymeric Matrix Stiffness on Osteogenic Differentiation of Mesenchymal Stem/Progenitor Cells: Concise Review

Mesenchymal stem/progenitor cells (MSCs) have a multi-differentiation potential into specialized cell types, with remarkable regenerative and therapeutic results. Several factors could trigger the differentiation of MSCs into specific lineages, among them the biophysical and chemical characteristics of the extracellular matrix (ECM), including its stiffness, composition, topography, and mechanical properties. MSCs can sense and assess the stiffness of extracellular substrates through the process of mechanotransduction. Through this process, the extracellular matrix can govern and direct MSCs' lineage commitment through complex intracellular pathways. Hence, various biomimetic natural and synthetic polymeric matrices of tunable stiffness were developed and further investigated to mimic the MSCs' native tissues. Customizing scaffold materials to mimic cells' natural environment is of utmost importance during the process of tissue engineering. This review aims to highlight the regulatory role of matrix stiffness in directing the osteogenic differentiation of MSCs, addressing how MSCs sense and respond to their ECM, in addition to listing different polymeric biomaterials and methods used to alter their stiffness to dictate MSCs' differentiation towards the osteogenic lineage.

In vitro comparison of cleaning efficacy and force of cylindric interdental brush versus an interdental rubber pick

BACKGROUND

Interdental brushes (IDB) are according to the actual evidence the first choice for cleaning interdental areas (IDR). Their size should be chosen individually according to the IDR morphology. However, interdental rubber picks (IRP) are appreciated better by the patients and are hence becoming more and more popular but the evidence regarding their efficacy is still limited. The aim of this in vitro study was to measure the experimental cleaning efficacy (ECE) and force (ECF) during the use of interdental brushes versus newer wireless types with rubber filaments (IRP), both fitted and non-fitted for different IDR.

METHODS

The medium size of a conical IRP (regular, ISO 2) with elastomeric fingers versus four sizes (ISO 1, 2, 3, 4) of cylindric IDB with nylon filaments (all Sunstar Suisse SA, Etoy, Switzerland) were tested. Interdental tooth surfaces were reproduced by a 3D-printer (Form 2, Formlabs Sommerville, MA, USA) according to human teeth and matched to morphologically equivalent pairs (isosceles triangle, concave, convex) fitting to three different gap sizes (1.0 mm, 1.1 mm, 1.3 mm). The pre-/post brushing situations at IDR (standardized, computer aided ten cycles) were photographically recorded and quantified by digital image subtraction to calculate ECE [%]. ECF were registered with a load cell [N].

RESULTS

Overall, a higher ECE was recorded for IDB compared to IRP (58.3 ± 14.9% versus 18.4 ± 10.1%; p < 0.001). ECE significantly depended on the fitting of the IDB. ECE was significant higher in isosceles triangle compared to concave and convex IDR for both IDB and IRP (p ≤ 0.001). ECF was lower for IDB (0.6 ± 0.4N) compared to IRP (0.8 ± 0.5N; p ≤ 0.001). ECE in relation to ECF increases with smaller IDB. For IRP highest values of ECF were found in the smallest IDR.

CONCLUSIONS

Within the limitations of an in vitro study, size fitted IDB cleaned more effectively at lower forces compared to conical IRP.

Hydrogels and Dentin-Pulp Complex Regeneration: From the Benchtop to Clinical Translation

Dentin-pulp complex is a term which refers to the dental pulp (DP) surrounded by dentin along its peripheries. Dentin and dental pulp are highly specialized tissues, which can be affected by various insults, primarily by dental caries. Regeneration of the dentin-pulp complex is of paramount importance to regain tooth vitality. The regenerative endodontic procedure (REP) is a relatively current approach, which aims to regenerate the dentin-pulp complex through stimulating the differentiation of resident or transplanted stem/progenitor cells. Hydrogel-based scaffolds are a unique category of three dimensional polymeric networks with high water content. They are hydrophilic, biocompatible, with tunable degradation patterns and mechanical properties, in addition to the ability to be loaded with various bioactive molecules. Furthermore, hydrogels have a considerable degree of flexibility and elasticity, mimicking the cell extracellular matrix (ECM), particularly that of the DP. The current review presents how for dentin-pulp complex regeneration, the application of injectable hydrogels combined with stem/progenitor cells could represent a promising approach. According to the source of the polymeric chain forming the hydrogel, they can be classified into natural, synthetic or hybrid hydrogels, combining natural and synthetic ones. Natural polymers are bioactive, highly biocompatible, and biodegradable by naturally occurring enzymes or via hydrolysis. On the other hand, synthetic polymers offer tunable mechanical properties, thermostability and durability as compared to natural hydrogels. Hybrid hydrogels combine the benefits of synthetic and natural polymers. Hydrogels can be biofunctionalized with cell-binding sequences as arginine-glycine-aspartic acid (RGD), can be used for local delivery of bioactive molecules and cellularized with stem cells for dentin-pulp regeneration. Formulating a hydrogel scaffold material fulfilling the required criteria in regenerative endodontics is still an area of active research, which shows promising potential for replacing conventional endodontic treatments in the near future.

Contemporary practices for mechanical oral hygiene to prevent periodontal disease

It is well established that dental plaque on teeth leads to gingivitis and periodontitis, and that several mechanical and chemical methods of plaque control can prevent gingivitis. The aim of the current review is to summarize and synthesize the available scientific evidence supporting practices for mechanical oral hygiene to prevent periodontal diseases. Evidence for contemporary practices of mechanical oral hygiene to prevent periodontal disease relies on studies of gingivitis patients. General recommendations concerning the ideal oral hygiene devices and procedures are still inconclusive. However, toothbrushing and interdental cleaning remain the mainstays of prevention of periodontal diseases. The primary approach requires individually tailored instruction for implementation of a systematic oral hygiene regimen.

Toll-like Receptor Expression Profile of Human Stem/Progenitor Cells Form the Apical Papilla

INTRODUCTION

Stem/progenitor cells from the apical papilla (SCAPs) demonstrate remarkable regenerative and immunomodulatory properties. During their regenerative events, SCAPs, similar to other stem/progenitor cells, could interact with their local inflammatory microenvironment via their expressed toll-like receptors (TLRs). The present study aimed to describe for the first time the unique TLR expression profile of SCAPs.

METHODS

Cells were isolated from the apical papilla of extracted wisdom teeth (n = 8), STRO-1 immunomagnetically sorted, and cultured to obtain single colony-forming units. The expression of CD14, 34, 45, 73, 90, and 105 were characterized on the SCAPs, and their multilineage differentiation potential was examined to prove their multipotent aptitude. After their incubation in basic or inflammatory medium (25 ng/mL interleukin 1 beta, 10³ U/mL interferon gamma, 50 ng/mL tumor necrosis factor alpha, and 3 × 10³ U/mL interferon alpha), a TLR expression profile for SCAPs under uninflamed as well as inflamed conditions was respectively generated.

RESULTS

SCAPs demonstrated all predefined stem/progenitor cell characteristics. In basic medium, SCAPs expressed TLRs 1-10. The inflammatory microenvironment up-regulated the expression of TLR1, TLR2, TLR4, TLR5, TLR6, and TLR9 and down-regulated the expression of TLR3, TLR7, TLR8, and TLR10 in SCAPs under the inflamed condition.

CONCLUSIONS

The present study defines for the first time a distinctive TLR expression profile for SCAPs under uninflamed and inflamed conditions. This profile could greatly impact SCAP responsiveness to their inflammatory microenvironmental agents under regenerative conditions in vivo.

Evaluation of a systematic digitized training program on the effectivity of subgingival instrumentation with curettes and sonic scalers in vitro

Objectives

Whereas the key role of subgingival instrumentation in periodontal therapy is well known, the influence of operators’ experience/training with different devices on treatment results is yet uncertain. Therefore, we assessed untrained undergraduate students, working on manikins, as to how effectively they learn to use curettes (GRA) and sonic scalers (AIR); hypothesizing that AIR will result in higher relative cleaning efficacy (RCE) than GRA.

Material and methods

Before baseline evaluation (T0), 30 operators (9 males, 21 females) received a 2-h theoretical lesson for both instruments, followed by a 12-week period with a weekly digitized training program for 45 min. During three sessions (T1–T3), the operators had to instrument six equivalent test teeth with GRA and AIR. At T0–T3, treatment time, proportion of removed simulated biofilm (RCE-b), and hard deposits (RCE-d) were measured.

Results

At T0, RCE-b was in mean(SD) 64.18(25.74) % for GRA, 62.25(26.69) % for AIR; (p = 0.172) and RCE-d 85.48(12.32) %/ 65.71(15.27) % (p < 0.001). At T3, operators reached highest RCE-b in both groups (GRA/AIR 71.54(23.90) %/71.75(23.05)%; p = 0.864); RCE-d GRA/AIR: 84.68(16.84) %/77.85(13.98) %; p < 0.001). Both groups achieved shorter treatment times after training. At T3, using curettes was faster (GRA/AIR 16.67(3.31) min/19.80(4.52) min; p < 0.001).

Conclusions

After systematic digitized training, untrained operators were able to clean 70% of the root surfaces with curettes and sonic scalers.

Clinical relevance

It can be concluded that a systematic digitized and interactive training program in manikin heads is helpful in the training of root surface debridement.

New experimental setup for the measurement of cleaning efficacy and force of interdental aids in 3D-reproduced interdental areas

BACKGROUND

Interdental rubber picks (IRP) have become a frequent and convenient alternative for interdental cleaning. However, only little evidence exists supporting the effectiveness of newer designs available on the market. Therefore, a new in vitro model was evaluated to measure the experimental cleaning efficacy (ECE), as well as the force needed for insertion and during the use of IRP, with high reproducibility.

METHODS

Five different sizes of commercially marketed IRP with elastomeric fingers (IRP-F) (GUM SOFT-PICKS® Advanced, Sunstar Deutschland GmbH, Schönau, Germany) or slats (IRP-S) (TePe EasyPick™, TePe D-A-CH GmbH, Hamburg, Germany) were tested. Interdental tooth surfaces were reproduced by a 3D-printer (Form 2, Formlabs Sommerville, MA, USA) according to human teeth and matched to morphologically equivalent pairs (isosceles triangle, concave, convex) fitting to different gap sizes (1.0 mm, 1.1 mm, 1.3 mm). The pre-/post brushing situations at interdental areas (standardized cleaning, computer aided ten cycles) were photographically recorded and quantified by digital image subtraction to calculate ECE [%]. Forces were registered with a load cell [N].

RESULTS

IRP-F have to be inserted with significant higher forces of 3.2 ± 1.8 N compared to IRP-S (2.0 ± 1.6 N; p < 0.001) independent of the size and type of artificial interdental area. During cleaning process IRP-S showed significantly lower values for pushing/pulling (1.0 ± 0.8 N/0.5 ± 0.4 N) compared to IRP-F (1.6 ± 0.8 N/0.7 ± 0.3 N; p < 0.001) concomitant to significantly lower ECE (19.1 ± 9.8 vs. 21.7 ± 10.0%, p = 0.002). Highest ECE was measured with largest size of IRP-F/IRP-S independent the morphology of interdental area.

CONCLUSIONS

New interdental cleaning aids can be tested by the new experimental setup supported by 3D printing technology. Within the limitations of an in vitro study, IRP-F cleaned more effectively at higher forces compared to IRP-S.

A retrospective assessment of different endodontic treatment protocols

Background

The aim of this study was to assess the clinical impact of non-surgical root canal treatments (NSRCT) performed with different treatment protocols on the probability of tooth survival without untoward events and to identify predictors influencing the outcome.

Methods

During the period from July 1999 to October 2016, 5,858 patients were identified in which 9,967 NSRCTs were performed. The treatments were followed up and divided into three groups. In Group 1 root canal treatment was performed with hand instruments, in Group 2 with multiple file rotary instruments and passive ultrasonic irrigation (PUI), and Group 3 was treated with Reciproc instruments and PUI. Untoward events were defined as orthograde retreatment, apicoectomy or extraction of the tooth after initial treatment. Weibull regression was used to analyse the data.

Results

A total of 9,938 cases could be included into the analyses. The results showed 5-years predicted survival rates without untoward events of 73.9% (95% CI [71.7%–76.1%]), 75.1% (95% CI [71.7%–78.0%]) and 78.4% (95% CI [75.1%–81.4%]) for study group 1 (N = 5,580), 2 (N = 1,700) and 3 (N = 2,658), respectively. The differences between Group 1 and 3 were statistically significant (p < 0.006). Higher age of the patient (per year increase) and number of earlier NSRCTs (per unit increase) reduce the survival without untoward events statistically significant (both p < 0.02), while treatment of premolars had a statistically significant lower hazard ratio [0.89 (95% CI [0.79–0.99]; p = 0.030)] compared to treatment of molars and anterior teeth. A higher number of supportive periodontal treatments (per unit increase) improved tooth survival without untoward events highly significant (p < 0.0001).

Discussion

More recent endodontic treatment protocols involving reciprocating instruments and PUI appear to be associated with higher tooth survival rates without untoward events compared to hand instruments.

Dental Stem Cell-Derived Secretome/Conditioned Medium: The Future for Regenerative Therapeutic Applications

Regenerative medicine literature has proposed mesenchymal stem/progenitor cell- (MSC-) mediated therapeutic approaches for their great potential in managing various diseases and tissue defects. Dental MSCs represent promising alternatives to nondental MSCs, owing to their ease of harvesting with minimally invasive procedures. Their mechanism of action has been attributed to their cell-to-cell contacts as well as to the paracrine effect of their secreted factors, namely, secretome. In this context, dental MSC-derived secretome/conditioned medium could represent a unique cell-free regenerative and therapeutic approach, with fascinating advantages over parent cells. This article reviews the application of different populations of dental MSC secretome/conditioned medium in in vitro and in vivo animal models, highlights their significant implementation in treating different tissue' diseases, and clarifies the significant bioactive molecules involved in their regenerative potential. The analysis of these recent studies clearly indicate that dental MSCs' secretome/conditioned medium could be effective in treating neural injuries, for dental tissue regeneration, in repairing bone defects, and in managing cardiovascular diseases, diabetes mellitus, hepatic regeneration, and skin injuries, through regulating anti-inflammatory, antiapoptotic, angiogenic, osteogenic, and neurogenic mediators.

How to train periodontal endoscopy? Results of a pilot study removing simulated hard deposits in vitro

OBJECTIVES

There is uncertainty regarding the benefits of periodontal endoscopy (PE) for subgingival instrumentation. Moreover, the influence of operators' experience and training with such a device on treatment results is unclear. Therefore, we compared in an in vitro study the use of PE for scaling and root planing (SRP) with the conventional non-surgical therapy, hypothesizing that using a PE allows to remove more simulated hard deposits than without (nPE), influenced by the operators' experience and training.

MATERIAL AND METHODS

A sonic device and Gracey curettes were utilized by 11 operators (six dentists, five dental hygienists) in periodontitis manikins heads. The time required for treatment and the proportion of removed simulated hard deposits by SRP were measured.

RESULTS

Using the PE led to a significant difference in removal of simulated hard deposits (%) (mean ± SD) irrespective of operators' experience (PE 90.78 ± 12.10% (range 58.80-100%); nPE 79.98 ± 22.15% (range 38.10-100%, p < 0.001)), sub-analyses for different tooth types demonstrated a significant difference in favor of PE for front teeth (p < 0.001) and in the upper jaw independent of the tooth type (p < 0.001). Comparison of treatment times for two quadrants with and without PE showed a significantly longer treatment time with PE (∆22.27 ± 17.98 mins, p <0.001).

CONCLUSIONS

Within the present pilot study, the use of PE led to more removal of simulated hard deposits but was concomitantly related to more time and financial effort. Using PE was most beneficial in the front area.

CLINICAL RELEVANCE

PE may provide additional benefits for the removal of hard deposits compared to traditional SRP. The beneficial effect of PE seems not to be influenced by operators experience nor by pocket probing depth.

Secreted frizzled-related protein 5 serum levels in human periodontitis-A nested case-control study

AIM

Recombinant secreted frizzled-related protein 5 (sFRP5) improved periodontal status in mice. Thus, this study aimed to investigate this finding in human periodontitis using an epidemiological approach.

MATERIALS AND METHODS

sFRP5 and wnt5a concentrations were determined in human serum from the Food Chain Plus cohort using ELISAs. A total of 128 patients with periodontitis and tooth loss and 245 patients with periodontitis without tooth loss were compared to 373 sex-, smoker-, age- and BMI-matched individuals in a nested case-control design.

RESULTS

Systemic sFRP5 serum levels were significantly lower in patients with periodontitis and tooth loss (2.5 [0.0-10.4] ng/ml, median [IQR]) compared to patients with periodontitis without tooth loss (6.0 [2.5-15.8] ng/ml, median [IQR], p = 0.04] and matched controls (7.0 [2.5-18.3] ng/ml, median [IQR], p = 0.02). No significant differences in sFRP5 serum levels were found among patients with periodontitis without tooth loss (6.0 [2.5-15.8] ng/ml, median [IQR]) and controls (3.1 [0.0-10.6] ng/ml, median [IQR], p = 0.06).

CONCLUSIONS

sFRP5 might serve as a novel biomarker for periodontitis severity. Modulating the inflammatory background of severe forms of periodontitis, in the time of precision medicine, needs to be revealed in further studies.

The periodontal stem/progenitor cell inflammatory-regenerative cross talk: A new perspective

Adult multipotent stem/progenitor cells, with remarkable regenerative potential, have been isolated from various components of the human periodontium. These multipotent stem/progenitor cells include the periodontal ligament stem/progenitor cells (PDLSCs), stem cells from the apical papilla (SCAP), the gingival mesenchymal stem/progenitor cells (G-MSCs), and the alveolar bone proper stem/progenitor cells (AB-MSCs). Whereas inflammation is regarded as the reason for tissue damage, it also remains a fundamental step of any early healing process. In performing their periodontal tissue regenerative/reparative activity, periodontal stem/progenitor cells interact with their surrounding inflammatory micro-environmental, through their expressed receptors, which could influence their fate and the outcome of any periodontal stem/progenitor cell-mediated reparative/regenerative activity. The present review discusses the current understanding about the interaction of periodontal stem/progenitor cells with their surrounding inflammatory micro-environment, elaborates on the inflammatory factors influencing their stemness, proliferation, migration/homing, differentiation, and immunomodulatory attributes, the possible underlying intracellular mechanisms, as well as their proposed relationship to the canonical and noncanonical Wnt pathways.

Retinol/inflammation affect stemness and differentiation potential of gingival stem/progenitor cells via Wnt/β-catenin

BACKGROUND AND OBJECTIVE

Inflammatory cytokines impact the course of periodontal disease, repair, and regeneration. Vitamin A and its metabolites are inflammation-modulatory biomolecules, affecting cellular pluripotency. The aim of this study was to investigate the effect of retinol and periodontal inflammatory cytokines (IL-1β/TNF-α/IFN-γ) on pluripotency and proliferative properties of gingival mesenchymal stem/progenitor cells (G-MSCs), for the first time.

MATERIAL AND METHODS

Human G-MSCs (n = 5) were STRO-1 immuno-magnetically sorted, characterized and expanded in basic medium (control group), in basic medium with IL-1β (1 ng/mL), TNF-α (10 ng/mL), and IFN-γ (100 ng/mL) (inflammatory group), in basic medium with retinol (20 μmol/L) (retinol group) and with retinol added to the inflammatory group (inflammatory/retinol group). β-catenin levels at 1 hour, cellular proliferation over 14 days, and colony-forming units (CFUs) at 14 days were investigated. Pluripotency gene expressions were examined at 1, 3, and 5 days via reverse transcription-polymerase chain reaction (RT-PCR). Multilineage differentiation potential was evaluated, following 5 days priming, using qualitative and quantitative histochemistry and RT-PCR.

RESULTS

G-MSCs were CD14^- , CD34^- , CD45^- , CD73⁺ , CD90⁺ , CD105⁺ , and showed mesenchymal stem/progenitor cells' hallmarks, CFUs, and multilineage differentiation potential. Intracellular β-catenin significantly declined in the stimulated groups (P < 0.001, Friedman test). Cellular proliferation at 72 hours was most prominent in the control and inflammatory group [Median cell numbers (Q25/Q75); 6806 (4983/7312) and 5414 (4457/7230), respectively], followed by an upsurge in the retinol group. At 14 days, the retinol group exhibited the highest CFUs [Median CFUs (Q25/Q75); 35 (20/58), P = 0.043, Wilcoxon signed-rank]. Nanog was most expressed in the inflammatory and retinol group [Median gene expression/PGK1 (Q25/Q75); 0.0006 (0.0002/0.0014) and 0.0005 (0.0003/0.0008)]. Inflammation significantly upregulated Sox2 expression [0.0002 (0.0008/0.0005)], while its expression was diminished in the retinol and inflammatory/retinol group (P < 0.001, Friedman test). Inflammatory/retinol group exhibited the highest multilineage differentiation potential.

CONCLUSION

Controlled short-term inflammatory/retinol stimuli activate the Wnt/β-catenin pathway, affecting G-MSCs' pluripotency, proliferation, and differentiation. The present findings provide further insights into the inflammatory-regenerative interactions and their modulation potential for G-MSCs-mediated periodontal repair/regeneration.

The accuracy of the auto-stop function of different endodontic devices in detecting the apical constriction

Background

Electronic apex locators (EALs) are modern devices used to determine the working length during root canal preparation. The newest endodontic motors provide an integrated EAL with auto-stop function to prevent instrumentation beyond the predefined working length during rotary root canal preparation. The aim of this study was to compare the accuracy of the auto-stop function of the VDW.Gold RECIPROC motor (VDW, Munich, Germany), the EndoPilot motor (Schlumbohm, Brokstedt, Germany) and the manual measurement with Raypex 6 (VDW, Munich, Germany) to detect the apical constriction (AC).

Methods

Ninety human teeth were chosen and randomly assigned to three experimental groups (30 teeth each): VDW.Gold RECIPROC motor continuous measuring (RCM), EndoPilot continuous measuring (ECM) and Raypex 6 manual measuring (RMM). When the measurement file reached the AC, the file was fixed in the tooth. The tooth was embedded in acrylic resin and the root tip was exposed, so that the histologic structure of the root canal and the file tip was visible for microscopic analysis. Afterwards, the distance of the file tip to the AC (D_AC) was automatically computed with a specially developed software tool.

Results

The mean D_AC were −13.18 μm (SD 88.46 μm) for RMM, −22.70 μm (SD 91.57 μm) for RCM and 18.74 μm (SD 88.11 μm) for ECM. The differences were not statistically significant (P = 0.181). The rates for instrumentation beyond the AC were not statistically different (Chi² = 4.753, p = 0.096).

Conclusions

All measurement methods showed a high accuracy in detecting the AC. The auto-stop function of these endodontic motors is a reliable addition to the endodontic armamentarium.

Global smoking-attributable burden of periodontal disease in 186 countries in the year 2015

AIM

We aimed to quantify the smoking-attributable burden of periodontal disease (PD).

METHODS

The association between smoking and PD was evaluated. Population, smoking and PD data from the Global Burden of Disease Study were used, and the burden in different sex and age groups in 186 countries in 2015 calculated, adjusted for PD prevalence and numbers of cigarettes smoked. No adjustment was performed in a sensitivity analysis.

RESULTS

The global smoking-attributable burden was 251,160 disability-adjusted life years (DALYs; 95% uncertainty interval: 190,721-324,241; sensitivity analysis: 344,041 DALYs) or 38.5 million cases. The burden was lower in females than males, and highest in the age group of the 50- to 69-year-olds. On super-regional level, the burden was highest in South-East Asia, East Asia and Oceania (83,052 DALYs), and high-income North America and Asia Pacific (55,362 DALYs). On regional level, it was highest in East Asia (70,845 DALYs), South Asia (30,808 DALYs) and North Africa and the Middle East (24,095 DALYs). On national level, it was highest in China (69,148 DALYs), India (29,362 DALYs) and the United States (12,714 DALYs). The relative smoking-attributable burden ranged between >25% in Suriname and <1% in Chad.

CONCLUSIONS

There is great need to monitor and tackle the smoking-attributable burden of PD.

Inhibition of Streptococcus mutans Growth and Biofilm Formation by Probiotics in vitro

To exert anticaries effects, probiotics are described to inhibit growth and biofilm formation of cariogenic bacteria such as Streptococcus mutans (SM). We screened 8 probiotics and assessed how SM growth or biofilm formation inhibition affects cariogenicity of probiotic-SM mixed-species biofilms in vitro. Growth inhibition was assessed by cocultivating probiotics and 2 SM strains (ATCC 20532/25175) on agar. Probiotics were either precultured before SM cultivation (exclusion), or SM precultured prior to probiotic cultivation (displacement). Inhibition of SM culture growth was assessed visually. Inhibition of SM biofilm formation on bovine enamel was assessed using a continuous-flow short-term biofilm model, again in exclusion or displacement mode. The cariogenicity of mixed-species biofilms of SM with the most promising growth and biofilm formation inhibiting probiotic strains was assessed using an artificial mouth model, and enamel mineral loss (ΔZ) was measured microradiographically. We found limited differences in SM growth inhibition in exclusion versus displacement mode, and in inhibition of SM 20532 versus 25175. Results were therefore pooled. Lactobacillus acidophilus LA-5 inhibited significantly more SM culture growth than most other probiotics. L. casei LC-11 inhibited SM biofilm formation similarly to other alternatives but showed the highest retention of probiotics in the biofilms (p < 0.05). Mineral loss from SM monospecies biofilms (ΔZ = 9,772, 25th/75th percentiles: 6,277/13,558 vol% × µm) was significantly lower than from mixed-species SM × LA-5 biofilms (ΔZ = 24,578, 25th/75th percentiles: 19,081/28,768 vol% × µm; p < 0.01) but significantly higher than from SM × LC-11 biofilms (ΔZ = 4,835, 25th/75th percentiles: 263/7,865 vol% × µm; p < 0.05). Probiotics inhibiting SM culture growth do not necessarily reduce the cariogenicity of SM-probiotic biofilms. Nevertheless, SM biofilm formation inhibition may be relevant in the reduction of cariogenicity.

TLR-induced immunomodulatory cytokine expression by human gingival stem/progenitor cells

During therapeutic application, mesenchymal stem cells (MSCs) may interact with their environment via their expressed toll-like-receptors (TLRs) leading to pro- or anti-inflammatory immune responses. The present study aimed to describe the gingival margin-derived stem/progenitor cells' (G-MSCs) TLR-induced immune regulatory response to specific TLR agonists. Gingival cells were obtained, immunomagnetically sorted via anti-STRO-1 antibodies and seeded out to achieve colony forming units (CFUs). G-MSCs were investigated for stem cell characteristics and TLR expression. Specific TLR agonists were applied and m-RNA expression of pro- and anti-inflammatory factors was analyzed via real-time polymerase chain reaction. G-MSCs showed all characteristics of stem/progenitor cells. All TLR agonists induced pro-inflammatory cytokines, except for the TLR3 agonist, which significantly promoted the anti-inflammatory response. (p⩽0.05, Wilcoxon-Signed-Ranks-Test). TLR-induced immunomodulation by G-MSCs could impact their therapeutic potential in vivo. Two distinctive pro-inflammatory and an anti-inflammatory TLR-induced phenotypes of G-MSCs become noticeable in this study.

Number of teeth predict depressive symptoms in a longitudinal study on patients with periodontal disease

OBJECTIVE

Periodontal disease is associated with a wide range of psychosocial risk-factors. Disease-related tooth-loss has been associated with an increase in depressive symptoms in cross-sectional studies. However, while depression is a known risk-factor for the outcome of chronic diseases, it remains unclear if tooth loss can also predict depressive symptoms over the course of treatment. Aim of the current pilot study was to test, to what extend the number of teeth predict depressive symptoms several years later.

METHODS

Tooth status of 310 patients with chronic and aggressive periodontitis was evaluated at the beginning of a specialized, university based outpatient treatment. We assessed depressive symptoms with the Patient Heath Questionnaire (PHQ) on average 13years later. Regression analyses were used to relate initial number of teeth to self-reported depression scores.

RESULTS

Fewer teeth at the beginning of the treatment were related to higher scores of depressive symptoms, even when controlling for several covariates.

CONCLUSIONS

Tooth loss is a potential risk-factor for the development of depression in periodontal disease. Further longitudinal studies that control for initial depressive symptoms are needed to identify disease mechanisms.

Efficacy of inter-dental mechanical plaque control in managing gingivitis--a meta-review

FOCUSED QUESTION

What is the effect of mechanical inter-dental plaque removal in addition to toothbrushing, on managing gingivitis using various formats of inter-dental self-care in adults based on evidence gathered from existing systematic reviews?

MATERIAL & METHODS

Three Internet sources were searched by a strategy designed to include systematic reviews on inter-dental cleaning devices. Plaque and gingivitis scores were the primary parameters of interest. Characteristics of selected papers were extracted. The potential risk of bias was estimated and the acquired evidence was graded.

RESULTS

Screening of 395 papers resulted in six systematic reviews. Two papers evaluated the efficacy of dental floss, two of inter-dental brushes (IDB), one of woodsticks and one of the oral irrigator. Weak evidence of unclear or small magnitude was retrieved that supported dental floss, woodsticks and the oral irrigator to reduce gingivitis in addition to toothbrushing. No concomitant evidence for an effect on plaque emerged. There is moderate evidence that IDBs in combination with toothbrushing reduce both plaque and gingivitis.

CONCLUSION

Evidence suggests that inter-dental cleaning with IDBs is the most effective method for inter-dental plaque removal. The majority of available studies fail to demonstrate that flossing is generally effective in plaque removal. All investigated devices for inter-dental self-care seem to support the management of gingivitis, however, to a varying extend.

Dental implants combined with sinus augmentation: What is the merit of bone grafting? A systematic review

PURPOSE

The aim of the present study was to systematically assess the current evidence on the effect of nongrafted compared to graft-assisted maxillary sinus floor elevation on implant survival/failure, endosinus bone gain, crestal bone loss, and bone density around dental implants.

MATERIALS AND METHODS

MEDLINE-PubMed, Cochrane-CENTRAL, and EMBASE databases were searched up to November 2015 for randomized controlled trials (RCTs) and controlled clinical trials-(CCTs), evaluating dental implants placed in combination with maxillary sinus elevation without and with bone grafting. Implant survival/failure served as the primary outcome, whereas endosinus bone gain, crestal bone loss, and bone density around dental implants were secondary outcomes. To assess possible bias, the Cochrane risk of bias tool was used. Data were extracted and a meta-analysis performed where appropriate.

RESULTS

Independent screening of 3180 papers resulted in six eligible experiments. Heterogeneity was observed among experiments. One experiment showed low, three unclear, and two a high risk of bias. The assessed outcomes showed no significant long-term differences between groups.

CONCLUSION

Within the limit of the current systematic review, nongrafted maxillary sinus floor elevation seems to be characterized by new bone formation and high implant survival rate comparable to bone-graft-assisted maxillary sinus floor augmentation. Further long-term studies are needed before definitive conclusions can be made.

Removal of simulated biofilm: an evaluation of the effect on root surfaces roughness after scaling

BACKGROUND

Despite the development of less invasive devices, a debate exists about the benefits and risks of hand versus powered root surface instrumentation used in supportive periodontal therapy (SPT). The aim of the in vitro study was to differentially compare plaque removal efficacy and root surface roughening of newly developed sonic, ultrasonic scaler, and curettes in the hands of experienced versus less experienced operators.

MATERIALS AND METHODS

Sonic (AIR), ultrasonic devices (TIG), and double-gracey curettes (GRA) were utilized by seven experienced (EO) and four less experienced operators (LO) for root surface instrumentation of standardized plastic teeth on manikins' heads in a randomized sequence. The proportion of residual simulated plaque (RSP area in %) was planimetrically assessed, and the average root surface roughness produced (Ra and ∆Ra in μm) was measured by a precision profilometer.

RESULTS

The uninstrumented root surfaces showed a Ra of (median (Q25/Q75)) 1.00 μm (0.83/1.16). Following instrumentation, EO left significantly less RSP than LO regardless of the used instruments (20.00 % (10.00/34.00) vs. 26.00 % (12.00/44.00) p < 0.001), whereas the ∆Ra values (0.29 μm (-0.04/0.96) vs. 0.35 μm (-0.04/1.01), p = 0.237) failed to show significant differences. The surface roughness was higher with GRA followed by AIR then TIG regardless of operators' experience (p < 0.001).

CONCLUSION

Within the limits of the present study, the sonic device was most efficient in plaque removal, while the ultrasonic device produced the least surface roughness.

CLINICAL RELEVANCE

All three tested instruments seem effective in the mechanical root debridement during SPT, whereat the ultrasonic device show the smoothest root surface of all.

Three-year randomized study of manual and power toothbrush effects on pre-existing gingival recession

AIM

To compare long-term effects of brushing with an oscillating-rotating power toothbrush or an ADA reference manual toothbrush on pre-existing gingival recession.

MATERIALS AND METHODS

In this controlled, prospective, single-blind, parallel-group study, healthy subjects with pre-existing recession were randomized and brushed with a power toothbrush (n = 55) or an ADA reference manual toothbrush (n = 54) for a 3-year study period. Subjects were required to brush their teeth twice daily for 2 min. using a standard fluoride toothpaste. During the study, subjects were assessed for clinical attachment loss and probing pocket depths to the nearest mm at six sites per tooth by the same calibrated examiner. Gingival recession was calculated at pre-existing sites as the difference between clinical attachment loss and probing pocket depths. Hard and soft oral tissues were examined to assess safety.

RESULTS

After 35 ± 2 months, mean gingival recession did not differ significantly between groups, but was significantly reduced from baseline (p < 0.001), from 2.35 ± 0.35 mm to 1.90 ± 0.58 mm in the power and from 2.26 ± 0.31 mm to 1.81 ± 0.66 mm in the manual group.

CONCLUSIONS

Gingival recession in subjects with pre-existing recession was significantly reduced after 3 years of brushing with either a power or manual toothbrush.

The effectiveness of dentifrices without and with sodium lauryl sulfate on plaque, gingivitis and gingival abrasion--a randomized clinical trial

OBJECTIVES

The aim of this study was to compare the efficacy of a dentifrice without sodium lauryl sulfate (SLS) to a dentifrice with SLS in young adults aged 18-34 years on gingivitis.

MATERIAL AND METHODS

One hundred twenty participants (non-dental students) with a moderate gingival inflammation (bleeding on probing at 40-70 % of test sites) were included in this randomized controlled double blind clinical trial. According to randomization, participants had to brush their teeth either with dentifrice without SLS or with SLS for 8 weeks. The primary outcome was bleeding on marginal probing (BOMP). The secondary outcomes were plaque scores and gingival abrasion scores (GA) as well as a visual analogue scale (VAS) score at exit survey. Baseline and end differences were analysed by univariate analysis of covariance (ANCOVA) test, between group differences by independent t test and within groups by paired sample t test.

RESULTS

BOMP improved within groups from on average 0.80 at baseline to 0.60 in the group without SLS and to 0.56 in the group with SLS. No statistical difference for BOMP, plaque and gingival abrasion was found between both groups. VAS scores for taste, freshness and foaming effect were significantly in favour of the SLS-containing dentifrice.

CONCLUSION

The test dentifrice without SLS was as effective as a regular SLS dentifrice on gingival bleeding scores and plaque scores. There was no significant difference in the incidence of gingival abrasion.

CLINICAL RELEVANCE

In patients diagnosed with gingivitis, a dentifrice without SLS seems to be equally effective compared to a dentifrice with SLS and did not demonstrate any significant difference in gingival abrasion. In patient with recurrent aphthous ulcers, the absence of SLS may even be beneficial. However, participants indicate that they appreciate the foaming effect of a dentifrice with SLS more.

Retention costs of periodontally compromised molars in a German population

AIM

This study assessed the long-term costs per retention year for periodontally affected molars.

METHODS

A cohort of 379 compliant subjects was retrospectively evaluated. Periodontal, restorative, endodontic, prosthetic and surgical treatment costs were estimated based on fee items of the private German health insurance. Costs/year were calculated and the impact of tooth- and subject-related factors on this cost-effectiveness ratio assessed using generalized linear-mixed modelling.

RESULTS

2306 molars received non-regenerative initial and supportive therapy and were followed until extraction or censoring (in mean (SD): 16.5 [6.8] years). Per year, 0.07 (SD: 0.12) deep scalings, 0.04 (0.11) open flap debridements, 0.01 (0.04) resective therapies and 2.49 (0.12) SPTs had been provided. Few teeth received non-periodontal treatments. Costs/year decreased significantly with each tooth a patient had at baseline (mean difference: -0.01, 95% CI: -0.02/-0.01 Euro/year), and increased with each mm of probing-pocket depth (0.04 [0.03/0.06] Euro/year), in upper (0.07 [0.11/0.31] Euro/year) or mobile molars (up to 0.33 [0.18/0.48] Euro/year), those with bone loss (up to 0.11 [0.04/0.17] Euro/year), endodontic treatment (0.24 [0.15/0.33] Euro/year), peri-apical lesions (0.24 [0.11/0.38]) and prosthetic treatment (0.54 [0.49/0.59] Euro/year).

CONCLUSIONS

Annual costs for retaining periodontally affected molars were limited, and associated mainly with tooth-level factors.

The effectiveness of a dentifrice without sodium lauryl sulphate on dental plaque and gingivitis - a randomized controlled clinical trial

OBJECTIVES

The purpose of the study was to evaluate the effect on dental plaque and gingivitis of a dentifrice without sodium lauryl sulphate (SLS) compared to two SLS-containing dentifrices.

MATERIAL AND METHODS

For this double-blind, parallel study, 90 volunteers having moderate gingival inflammation (≥40%) were randomly divided among three groups: one group using non-SLS dentifrice containing enzymes, colostrum and low concentrations of zinc and two control groups each using different SLS-containing dentifrices. Dental plaque scores (Turesky modification of Quigley & Hein) and gingivitis scores (Bleeding On Marginal Probing) were assessed at baseline, after 2 and 4 weeks.

RESULTS

Eighty-nine participants provided evaluable data. A slight decrease in gingivitis scores was observed for all groups over 4 weeks, which was statistically significant for the non-SLS group. Mean values for dental plaque scores did not show major differences over 4 weeks. For both parameters, no significant differences between groups could be observed at any time point. Patient appreciation was in favour of the SLS groups especially regarding the foaming effect.

CONCLUSION

No significant differences could be observed with respect to the effect on plaque and gingivitis between SLS-containing and SLS-free dentifrice containing enzymes, colostrum and low concentration zinc. Patients enjoyed the duration of taste and the 'foaming effect' of SLS-containing dentifrices better.

Toll-like Receptor Expression Profile of Human Dental Pulp Stem/Progenitor Cells

INTRODUCTION

Human dental pulp stem/progenitor cells (DPSCs) show remarkable regenerative potential in vivo. During regeneration, DPSCs may interact with their inflammatory environment via toll-like receptors (TLRs). The present study aimed to depict for the first time the TLR expression profile of DPSCs.

METHODS

Cells were isolated from human dental pulp, STRO-1-immunomagnetically sorted, and seeded out to obtain single colony-forming units. DPSCs were characterized for CD14, CD34, CD45, CD73, CD90, CD105, and CD146 expression and for their multilineage differentiation potential. After incubation of DPSCs in basic or inflammatory medium (interleukin-1β, interferon-γ, interferon-α, tumor necrosis factor-α), TLR expression profiles were generated (DPSCs and DPSCs-i).

RESULTS

DPSCs showed all characteristics of stem/progenitor cells. In basic medium DPSCs expressed TLRs 1-10 in different quantities. The inflammatory medium upregulated the expression of TLRs 2, 3, 4, 5, and 8, downregulated TLRs 1, 7, 9, and 10, and abolished TLR6.

CONCLUSIONS

The current study describes for the first time the distinctive TLR expression profile of DPSCs in uninflamed and inflamed conditions.

Removal of simulated biofilm: a preclinical ergonomic comparison of instruments and operators

BACKGROUND

Periodontal scaling might cause musculoskeletal disorders, and scaling instruments might not only have different effectiveness and efficiency but also differ in their ergonomic properties. The present study assessed ergonomic working patterns of experienced (EO) and less experienced operators (LO) when using hand and powered devices for periodontal scaling and root planning.

METHODS

In an experimental study using periodontally affected manikins, sonic (AIR), ultrasonic (TIG) and hand instruments (GRA) were used by 11 operators (7 EO/4 LO) during simulated supportive periodontal therapy. Using an electronic motion monitoring system, we objectively assessed the working frequency and positioning of hand, neck and head. Operators' subjective evaluation of the instruments was recorded using a questionnaire.

RESULTS

Hand instruments were used with the lowest frequency (2.57 ± 1.08 s(-1)) but greatest wrist deviation (59.57 ± 53.94°). EO used instruments more specifically than LO, and generally worked more ergonomically, with less inclination of head and neck in both the frontal and sagittal planes, especially when using hand instruments. All groups found hand instruments more tiring and difficult to use than powered instruments.

CONCLUSION

Regardless of operators' experience, powered instruments were used more ergonomically and were subjectively preferred compared to hand instruments.

CLINICAL RELEVANCE

The use of hand instruments has potential ergonomic disadvantages. However, with increasing experience, operators are able to recognise and mitigate possible risks.

Evaluation of job satisfaction and working atmosphere of dental nurses in Germany

OBJECTIVES

The purpose of the study was to assess the level of job satisfaction of dental nurses in ambulatory care and to explore the impact of aspects of working atmosphere on and their association with job satisfaction.

METHODS

This cross-sectional study was based on a job satisfaction survey. Data were collected from 612 dental nurses working in 106 dental care practices. Job satisfaction was measured with the 10-item Warr-Cook-Wall job satisfaction scale. Working atmosphere was measured with five items. Linear regression analyses were performed in which each item of the job satisfaction scale was handled as dependent variables. A stepwise linear regression analysis was performed with overall job satisfaction and the five items of working atmosphere, job satisfaction, and individual characteristics.

RESULTS

The response rate was 88.3%. Dental nurses were satisfied with 'colleagues' and least satisfied with 'income.' Different aspects of job satisfaction were mostly associated with the following working atmosphere issues: 'responsibilities within the practice team are clear,' 'suggestions for improvement are taken seriously,' 'working atmosphere in the practice team is good,' and 'made easier to admit own mistakes.' Within the stepwise linear regression analysis, the aspect 'physical working condition' (β = 0.304) showed the highest association with overall job satisfaction. The total explained variance of the 14 associated variables was 0.722 with overall job satisfaction.

CONCLUSIONS

Working atmosphere within this discrete sample of dental care practice seemed to be an important influence on reported working condition and job satisfaction for dental nurses. Because of the high association of job satisfaction with physical working condition, the importance of paying more attention to an ergonomic working position for dental nurses to ensure optimal quality of care is highlighted.

[Prevention and Information for Patients Undergoing Periodontal Treatment: Potentials for Improvement from the Patients' Perspective]

2 334 patients from 29 dental practices took part in a written survey on their experiences with dental treatment in general as well as treatment of periodontal disease (response rate 80.8%). 72.6% of all participating patients fully agreed that they could recommend their dentist to their friends. 63.6% of patients undergoing treatment of periodontitis (N=328) rated this treatment as "excellent". However, for important aspects (prevention, patient information, treatment) potentials for improvement became obvious. 43.7% of patients treated for periodontitis were not completely satisfied with information on how this disease develops; 40.7% saw potentials for better information on preventive care (dental-hygiene, nutrition). An even higher percentage of patients actually not treated for periodontitis was interested in more information on prevention (51.4%). The results of the survey show that dentists should offer information and exercise on how to prevent periodontal desease more actively. There is a lack of research on the present state of affairs and potentials for improvement concerning treatment and prevention of periodontitis including the patients' perspective.

Resin Infiltration of Fissure Caries with Various Techniques of Pretreatment in vitro

The resin infiltration technique might be used for occlusal caries lesions in order to arrest their progression. This in vitro study evaluated the influence of various modifications of the infiltration technique on the penetration abilities of the infiltrant into occlusal lesions. Extracted human molars and premolars (n = 140) with non-cavitated white spot lesions were randomly allocated to 7 groups. As control, specimens were etched with 15% hydrochloric acid (HCl) gel for 120 s and resin infiltrated for 180 s (Icon; DMG). As modification HCl gel reduced in surface tension and viscosity with and without abrasives was applied using 3 different types of brushes either to oscillate or rub the HCl gel onto the enamel surface. The median maximum lesion depth was 1,232 µm (interquartile range 882-1,513). Compared with the control procedure [23% (16/50)] a higher percentage penetration was observed if the HCl gel was mixed with a small amount of abrasives were rubbed into the fissures using a modified brush with stiff bristles that were adjusted to the fissure relief for either 120 s [100% (64/100)] or 30 s [98% (61/100); p < 0.05; Mann-Whitney test]. All other experimental treatments resulted in penetration results in-between. It can be concluded that the use of an abrasive HCl gel in conjunction with a modified brush mostly enhances resin infiltration into fissure caries lesions. © 2014 S. Karger AG, Basel

Spatter contamination in dental practices--how can it be prevented?

Infectious diseases endanger all dental personnel during treatment, especially when spatter and aerosols are produced. Therefore, there is a strong need for better infection control principles during all treatments. The purpose of this in-vitro pilot study was to measure the environmental spatter contamination through a fluorescence technique. Scaling was performed using different power-driven devices and high-volume evacuation combined with a newly developed cannula (PS), standard suction cannulas (STS) and saliva ejectors (CDS).

MATERIAL AND METHODS

One sonic (AIR) and two ultrasonic devices (TIG, VEC) were utilized to remove biofilm from 168 artificial teeth in a manikin head. Teeth were scaled for 120s supra- or subgingivally. The spatter contamination of an area of 1.5m2 around the manikin head was assessed.

RESULTS AND CONCLUSIONS

The contaminated area (%) was significantly different for the AIR (median [25th; 75th percentiles]: 2.5 [1.16; 6.05]) versus TIG (0.25 [0.18; 0.88]) and VEC (0.08 [0.06; 0.1]) (p<0.001). Irrespective of the instrument, subgingival scaling led to a less contaminated area (0.18 [0.07; 1.05]) than supragingival scaling (0.34 [0.1; 2.24]) (p < 0.001). High-volume evacuation combined with STS (0.17 [0.07; 1.04]) and PS (0.18 [0.07; 1.14]) reduced the contamination similarly (p=0.302) and was more effective compared to CDS (1.01 [0.12-5.78]) (p<0.001; p=0.002). Beside the limitation of an in-vitro investigation, it can be conclude that only high-volume evacuation with an adequately calibrated cannula is capable of significantly reducing the amount of spatter contamination produced during power-driven scaling.

Subgingival instrumentation to remove simulated plaque in vitro: influence of operators' experience and type of instrument

BACKGROUND

There is uncertainty regarding the benefits and risks of hand versus powered root surface instrumentation. Moreover, the influence of operators' experience on treatment results is unclear. We compared newly developed sonic, ultrasonic and hand instruments, hypothesizing that powered devices allow to remove more simulated plaque in less time than hand instruments, with significant influence of operators' experience.

METHODS

Sonic scaler (AIR), ultrasonic scaler (TIG) device and double Gracey curettes (GRA) were utilized by seven experienced operators (EOs) and four less experienced operators (LOs) in periodontitis manikin heads. The time required for treatment, the proportion of residual-simulated plaque and the weight loss caused by scaling as a proxy for root surface destruction were measured.

RESULTS

Using different instruments led to significantly different proportions of removed simulated plaque regardless of operators' experience (AIR, 80.2 ± 21.3 %, TIG, 69.9 ± 22.5 %, GRA, 73.1 ± 20.0 %) (p < 0.001). Treatment times did not significantly differ between EO and LO (p > 0.05). Weight loss was increased when using hand instead of powered instruments (p < 0.001), with significantly higher weight loss induced by LO than EO (p = 0.004).

CONCLUSION

Within the present study, EO did not remove more simulated plaque in less time but induced less root surface destruction. Using a sonic device was most beneficial for plaque removal.

CLINICAL RELEVANCE

Successful root surface debridement requires both time and training regardless of the used instrument. Hand instruments might cause more damage to root surfaces, especially in the hands of less experienced operators.