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This in vitro investigation should identify the effect of protective liners on dentine bond strength of a polyacid modified resin composite to dentine of primary teeth.Forty-two extracted caries-free primary molars were randomly assigned to seven groups (n = 6) and flattened. Six test groups were centrally covered with different protective liners/base materials: Kerr Life (KL), IRM zinc oxide eugenol cement (IRM), Ketac Bond (KB), Vitrebond (VB), Dycal (DY), and mineral trioxide aggregate (MTA). Specimens were bonded with PrimeBond NT (PB) and restored with Dyract eXtra. The control group (C) did not receive liner pretreatment. After 24-h storage in Aqua dest. (37 °C), specimens were cut and regional microtensile bond strengths of the uncovered areas were tested. Fractography was conducted under a light microscope and further interface/surface analyses were performed under a SEM. Statistical appraisal was carried out using oneway ANOVA (mod. LSD test; p 0.05).Independent of the distance to the applied liner, all groups exhibited inferior μ-TBS to dentine of primary teeth compared to the control group (p 0.05). The results were as follows in MPa(SD)Protective liners significantly reduced μ-TBS to dentine of primary teeth.

Objectives The aim of this study was to investigate whether file design and taper significantly influence microcrack initiation during machine preparation. Materials and methods Sixty extracted teeth with straight single canals were selected. The teeth were randomly assigned to four groups based on their root canal anatomy and the corresponding NiTi rotary file system (I, Mtwo; II, ProTaper Universal; III, F6 SkyTaper; control, no preparation and filling). The root canals of the experimental groups were filled using the single-cone technique. The tested teeth were all subjected to a mechanical chewing simulation with flat lead loading over a period of 3 years (corresponding to 150,000 cycles). The teeth were checked for dentinal defects (accumulative crack growth in length) under the digital microscope (Keyence VHX-5000) at time 0 (baseline prior to chewing simulation) and after 3, 6, 12, 24, and 36 months of loading. The cumulative crack increase was statistically analyzed using the Kruskal–Wallis test, Jonckheere–Terpstra test, and the Wilcoxon rank-sum test. The significance was set at p Results In contrast to preparation with greater-tapered instruments, ProTaper Universal (group II) and F6 SkyTaper (group III) instrumentation with the smaller tapered Mtwo files (group I) showed less accumulative propagation of craze lines (p Conclusion Instruments with greater taper for root canal instrumentation should be used with care to avoid negative long-term effects in the form of propagation of dentinal defects over time. A positive cutting-edge angle and a smaller taper have a positive effect on a lower craze line development. Clinical relevance Instruments with a positive cutting-edge angle and a smaller taper are beneficial for the long-term preservation of dentinal tooth structure.

ZusammenfassungDentales Amalgam wird seit über 180 Jahren erfolgreich in der zahnärztlichen Füllungstherapie kariöser Läsionen eingesetzt. Es ist langlebig, in der Verarbeitung wenig techniksensitiv und damit fehlertolerant. Seit vielen Jahren befindet sich das dentale Amalgam jedoch in der öffentlichen Diskussion, v. a. wegen seines Quecksilberanteils von ca. 50 %. Seit Veröffentlichung des „Minamata-Übereinkommens“ im Jahr 2013 mit dem primären Ziel, die Ausleitung anthropogenen Quecksilbers in die Umwelt zu reduzieren, ist die zwischenzeitlich fast verstummte Amalgamkritik wieder deutlich lauter geworden. Ein weiterer nicht unerheblicher Nachteil des Amalgams ist die silbrig-schwärzliche Farbe, die heute den ästhetischen Erfordernissen der Patienten oft nicht mehr entspricht.Der vorliegende Beitrag skizziert die Grundproblematik von Amalgam vor dem Hintergrund multipler biologischer, klinischer und gesundheitspolitischer Aspekte. Es wird Bezug genommen zu möglichen Auswirkungen, insbesondere des Minamata-Übereinkommens, auf gesetzliche Regelungen sowie auf die Verwendung von Werkstoffen und damit auch auf das Versorgungssystem der Zukunft. Außerdem werden mögliche Materialalternativen sowie biomedizinischer Forschungsbedarf auf dem Gebiet der restaurativen Zahnerhaltung dargestellt und abschließend die Frage gestellt, ob wir überhaupt die richtige Diskussion führen.

The aim of the present cross-sectional study was to assess and compare the prevalence of MIH among 6–12-year-old school children living either in a rural area of Central Hesse (Germany) or in the city of Frankfurt on the Main (Germany). A possible association between hypomineralised second primary molars (HSPM) and MIH was investigated. Furthermore, the MIH prevalence data of the rural area were compared with those of a previous study conducted in this area in the school year 2002/2003. In the school year 2014/2015, 2103 children (6–12 years of age) were examined during the annual school-based dental examinations prescribed by law at nine schools in the rural area of Central Hesse (LDK) and five schools in the city of Frankfurt on the Main (Ffm). Eight previously calibrated dentists working for the public healthcare authorities assessed the prevalence of HSPM/MIH (EAPD criteria/severity scale by Wetzel and Reckel) and the caries experience (dmft/DMFT). The prevalence of HSPM/MIH amounted 3.2%/9.4% in LDK and 2.9%/17.4% in Ffm. In the majority of cases, children with MIH had demarcated opacities. In LDK, hypomineralised first permanent molars were most commonly affected by severity degree 2, whereas in Ffm, severity degree 1 was predominant. Children suffering from HSPM had an odds ratio of 11.32 (95% CI: 6.73–19.03) for having MIH as well. Compared with the results of 2002/2003 in LDK (prevalence of MIH 5.9%), the MIH prevalence increased by 3.5% in the rural area. All in all, the caries experience among children under investigation was low (DMFT 0.14–0.15). MIH may be diagnosed in school children living in different areas of Germany with regional variations (rural-urban comparison). The presence of HSPM is of predictive value for MIH. The increasing number of hypomineralised first permanent molars over 12 years of time in the rural area indicates a need for further investigation on the aetiology of MIH.

Carious or traumatised teeth with a normal pulp status or with reversible pulpitis need an indirect or direct pulp capping procedure to keep the pulp vital. To evaluate the clinical outcome of both interventions for treating vital primary teeth. Two reviewers on Pubmed and ISI Web of Science performed a comprehensive literature review of publications from 1966 until December 2017. Among PubMed abstracts, publications were selected according to the following criteria: prospective clinical study, correct indication for the performed treatment, and clear definition of clinical and/or radiographic success criteria. The strict selection criteria limited the amount of randomised controlled trials (RCT) or controlled clinical trials (CT); especially for “indirect pulp therapy”, “direct pulp capping” and the number of RCTs was limited. Based on a systematic review (20 controlled clinical studies or randomised controlled clinical studies), the following statements can be given: Due to the opportunity of tissue repair, indirect pulp treatment can be an acceptable procedure for reversible pulp inflammation. The use of adhesives for indirect pulp capping in a single-visit procedure after gentle caries removal can be recommended. Successful pulp capping is possible under defined conditions (symptom-free tooth, disinfection of pulp exposures, Class-I cavity) and appropriate sealing of the cavity with an effective dentine seal being a conditio sine qua non. There is maximum evidence for the use of disinfecting solutions prior to pulp capping and Dycal as pulp capping material. Longer follow-up periods, more clinical studies, comparable conditions, and clear definitions of evaluation criteria are needed to confirm the results of endodontic treatment in primary teeth.

The aim of this ex-vivo study was to evaluate the impact of cavity size and glass-fiber post (GFP) placement on the load capability of endodontically treated maxillary incisors directly restored with resin composite. Ninety-six extracted human maxillary central incisors were endodontically treated and distributed to four groups (n = 24): access cavity (A), access cavity and uni-proximal class III cavity (U), access cavity and bi-proximal class III cavity (B), and decoronated tooth (D). Specimens were restored with resin composite, and 12 specimen of each group received an adhesively placed glass-fiber post (P). Prior to linear loading, specimens were exposed to thermo-mechanical loading (TCML). Statistical analysis was performed using log-rank test after TCML, Kruskall-Wallis and Mann-Whitney U test to compare load capabilities (Fmax). Significantly more failures occurred in group D for specimens without GFP during TCML (p = 0.001). Fmax (mean (SD) in N was (A) 513 (124), (AP) 554 (201), (U) 438 (171), (UP) 537 (232) (B) 483 (219), (BP) 536 (281), D 143 (181), and DP 500 (331), and differed significantly among groups (p = 0.003). Pair-wise comparison revealed lower Fmax values for group D compared to all other groups (p

Using a 445-nm semiconductor laser for tissue incision, an effective cut is expected due to the special absorption properties of blue laser light in soft tissues. The aim of the present study was the histological evaluation of tissue samples after incision with a 445-nm diode laser. Forty soft tissue specimens were obtained from pork oral mucosa and mounted on a motorized linear translation stage. The handpiece of a high-frequency surgery device, a 970-nm semiconductor laser, and a 445-nm semiconductor laser were connected to the slide, allowing a constant linear movement (2 mm/s) and the same distance of the working tip to the soft tissue’s surface. Four incisions were made each: (I) 970-nm laser with conditioned fiber tip, contact mode at 3-W cw; (II–III): 445-nm laser with non-conditioned fiber tip, contact mode at 2-W cw, and non-contact mode (1 mm) at 2 W; and (IV): high-frequency surgery device with straight working tip, 90° angulation, contact mode at 50 W. Histological analysis was performed after H&E staining of the embedded specimens at 35-fold magnification. The comparison of the incision depths showed a significant difference depending on the laser wavelength and the selected laser parameters. The highest incision depth was achieved with the 445-nm laser contact mode (median depth 0.61 mm, min 0.26, max 1.17, interquartile range 0.58) (p

The objective of this study was to investigate the effect of different glass ionomer cements on secondary caries inhibition in a fully automated in vitro biofilm model. One hundred and twenty-four extracted third molars received class V cavities and were filled with one conventional (Ketac Molar/KM), and two resin-modified glass ionomer cements (Photac Fil/PF, Ketac N100/KN, 3M Espe). A bonded resin composite (Single Bond Plus/Filtek Supreme XTE) served as control. After 14 days water storage at 37 °C, specimens were thermocycled (10,000 × 5/55 °C). Over a period of 10 days, specimens were subjected to cariogenic challenge for 3/4/6 h/day. Demineralization was caused by Streptococcus mutans (DSM 20523) alternatingly being rinsed over specimens using artificial saliva. After biological loading, teeth were cut longitudinally and demineralization depths were evaluated at the margins and at a distance of 0.5 mm from the margins using fluorescence microscopy. Marginal quality was investigated under a SEM at ×200 magnification. Four-hour demineralization depths were for enamel margins (EM), enamel (E), dentin margin (DM), and dentin (D) (μm ± SD): KM: EM 12 ± 8, E 33 ± 7, DM 56 ± 11, D 79 ± 6; PF: EM 19 ± 13, E 34 ± 13, DM 53 ± 10, D 77 ± 12; and KN: EM 26 ± 5, E 38 ± 6, DM 57 ± 11, D 71 ± 7. For all glass ionomer cements (GICs), demineralization depth at the margins was less compared to 0.5 mm distance, with demineralization depth having been correlated to duration of cariogenic challenge (ANOVA [mod. LSD, p

Halbleiter-Laser-Systeme finden in der Zahnmedizin sowohl in der Diagnostik als auch in der Therapie Anwendung. In Abhangigkeit von der verwendeten Wellenlange und den Energieeinstellungen werden vor allem fotochemische und gewebeabtragende/fotothermische Eigenschaften genutzt. Uber die Messung von Fluoreszenzerscheinungen konnen kariose Lasionen und Konkremente von gesunder Zahnhartsubstanz unterschieden und quantifiziert werden. Die antimikrobielle fotodynamische Therapie („antimicrobial photodynamic therapy“, aPDT) dient der nichtthermischen Abtotung pathogener Bakterien. Die „low-level laser therapy“ (LLLT) beruht auf der Erhohung der Mikrozirkulation und der Steigerung der Mitoserate zur verbesserten Geweberegeneration. Hohere Energieparameter ermoglichen auch Inzision und Exzision von Weichgeweben durch Ablation im Rahmen chirurgischer Eingriffe. Somit konnen Halbleiter-Laser-Systeme in einer Vielzahl zahnarztlicher Therapiemasnahmen eingesetzt werden und konventionelle Verfahren erganzen oder auch ersetzen.

In a controlled prospective split-mouth study, clinical behavior of two different resin composites in extended class II cavities was observed over 8 years. Thirty patients received 68 direct resin composite restorations (Solobond M/Grandio, Voco—n = 36; Syntac/Tetric Ceram, Ivoclar Vivadent—n = 32) by one dentist in a private practice. Thirty-five percent of cavities revealed no enamel at the bottom of the proximal box, 48 % of cavities provided

Background This study was carried out as a prospective clinical field study with the aim of evaluating the clinical performance of Equia Fil® with a nanofilled resin coating and the conventional Fuji IX GP® fast with an LC coating according to the World Dental Federation (FDI) restoration material evaluation criteria. Methods The clinical performance of Equia Fil® and Fuji IX GP® fast was evaluated on permanent posterior teeth of 643 adult patients aged between 20 to 80 years old in randomly selected clinics across Germany. Occlusal cavities in posterior permanent teeth were restored with Equia Fil® with a nanofilled, light-cured resin coating (n = 515) and Fuji IX GP® fast with an LC coating (n = 486). Direct clinical assessment as well as photographic assessment and assessment of stone casts of the restorations were made at 1 year, 2 years, 3 years, and 4 years. Results In 4 years, a total of 1001 fillings from both materials were placed by 111 dentists in 643 patients. Random slope models showed that the Equia filling system had overall lower odds of obtaining a delta event (material needs replacement) in comparison to Fuji IX GP® fast with an LC coating within all models. In both materials, filling size/surface was the most important component affecting the clinical performance of the materials. When measuring the odds of obtaining a delta event (material needs replacement), the odds ratios jumped to approximately 43 and 296 times for class II (two surfaces) and class II mesial-occlusal-distal (three surfaces) respectively in comparison to class I fillings. Conclusion Both materials showed similar good overall performance in class I cavities; however, when including numbers from both class I and II fillings, the Equia system with a nanofilled resin coating showed better overall performance with fewer failures in all the follow-up intervals. Nonetheless, the percentage of unsatisfactory to poor fillings according to the FDI criteria was relatively high in two-surface class II fillings and higher in three-surface class II fillings for both materials. Trial registration Deutsches Register Klinischer Studien (German Clinical Trials Register): DRKS00004220. (www.germanctr.de). Registration date: 6 Sept 2012. Electronic supplementary material The online version of this article (doi:10.1186/s13063-016-1339-8) contains supplementary material, which is available to authorized users.

OBJECTIVES The aim was to study the impact of the defect size of endodontically treated incisors compared to dental implants as abutments on the survival of zirconia two-unit anterior cantilever-fixed partial dentures (2U-FPDs) during 10-year simulation. MATERIALS AND METHODS Human maxillary central incisors were endodontically treated and divided into three groups (n = 24): I, access cavities rebuilt with composite core; II, teeth decoronated and restored with composite; and III as II supported by fiber posts. In group IV, implants with individual zirconia abutments were used. Specimens were restored with zirconia 2U-FPDs and exposed to two sequences of thermal cycling and mechanical loading. Statistics: Kaplan-Meier; log-rank tests. RESULTS During TCML in group I two tooth fractures and two debondings with chipping were found. Solely chippings occurred in groups II (2×), IV (2×), and III (1×). No significant different survival was found for the different abutments (p = 0.085) or FPDs (p = 0.526). Load capability differed significantly between groups I (176 N) and III (670 N), and III and IV (324 N) (p

Background: Despite an overall caries decline in children, still 50–60% of carious primary teeth of 6-year-olds remain untreated, in 3-year-olds 13%. There are an increasing number of poli-caries patients with insufficiently treated primary teeth. Therefore, early treatment is fundamental. Review: The assessment and indication for the use of restorative materials can be summarized as follows: Glass ionomer cements (GIC) are associated with easy handling and high fluoride release. This makes them attractive especially for Class I cavities in uncooperative children. However, low flexural strength causes high fracture rates in Class II cavities. Further developments (viscous and resin-modified GIC) have improved handling characteristics, but conventional non-resin-modified GIC are still prone to fracture. Compomers exhibit a clear potential as an alternative to amalgam. Long-term results are good even in stress-bearing areas. The compliance of the child should at least last long enough for adhesive application. Resin composites are still the most time-consuming alternative. Under a correct application protocol, resin composites behave in a similar manner to compomers. Therefore, the effort has to be judged individually. Finally, especially in severely decayed teeth and after endodontic treatment, preformed metal crowns should be taken into account as a last and appropriate alternative to direct restorations. Conclusion: Based on the high clinical success rates, compomers with self-etch adhesives can be recommended for restorative therapy in anterior and posterior primary teeth.

Background The objective of this study was to determine whether the addition of microsilver or nanosilver particles to an orthodontic primer affects shear bond strength (SBS) and bracket/adhesive failure. Methods Bovine incisors were randomly divided into six groups with 16 specimens in each: In group 1 (control), brackets were bonded with Transbond™ XT primer. In the experimental groups, microsilver (groups 2 and 3) and nanosilver (groups 4–6) particles of different sizes were added to Transbond XT primer and light cured for 15 seconds [group 2: 0.1% (w/w) microsilver particle size 3.5–18 μm; group 3: 0.3% (w/w) microsilver particle size 3.5–18 μm; group 4: 0.11% (w/w) nanosilver particle size 12.6–18.5 nm; group 5: 0.18% (w/w) nanosilver particle size 12.6–18.5 nm; group 6: 0.33% (w/w) nanosilver particle size 12.6–18.5 nm]. Thereafter, brackets were bonded by light curing the adhesive for 20 seconds. After 24 hours of storage in distilled water at 37°C, SBS was measured with a Zwicki 1120 testing machine. The adhesive remnant index and the prevalence of silver spots on the specimen surface were determined under 10× magnification. Statistical two-way analysis of variance was performed to compare SBS, and a chi-square test was used to compare ARI scores and the prevalence of silver spots. Results No significant differences in SBS (control: 16.59 ± 6.82 MPa; group 2: 20.6 ± 4.19 MPa; group 3: 16.98 ± 4.84 MPa; group 4: 17.15 ± 5.92 MPa; group 5: 20.09 ± 3.35 MPa; group 6: 16.44 ± 4.51 MPa; p > 0.665) and ARI scores (p = 0.901) were found between the control group and any experimental group. Only experimental groups with nanosilver particles revealed statistically more silver spots on the remaining adhesive. Conclusions Addition of small concentrations of microsilver or nanosilver particles affects neither SBS nor ARI scores. Addition of nanosilver particles results in silver spots in the remaining primer visible under 10× magnification. Further studies are needed to investigate the anti-caries potential and clinical performance of conventional orthodontic primer with incorporated nanosilver or microsilver particles.

Elastic modulus (EM), initial fracture strength (FS) and flexural fatigue limit (FFL) of dental restorative materials were measured in a simulated oral environment to correlate mechanical response under the influence of water with the chemical nature of the test materials under investigation. One resin composite (RC; Tetric Ceram, Ivoclar-Vivadent Corp., Liechtenstein), an ion-leaching resin composite (ILRC; Ariston pHc, Ivoclar-Vivadent Corp., Liechtenstein) a compomer (CO; Dyract AP, Dentsply Corp., USA) and a glass-ionomer cement (GIC; Ketac Molar, 3MEspe Corp., Germany) were tested. Static EM, FS and dynamic FFL experiments were performed. The FFL was determined under cyclic loading for 10(5) cycles in terms of a staircase approach. The materials were stored for 1, 8, 30, 90 and 180 days in 37 degrees C distilled water, respectively. The RC degraded over time due to water adsorption followed by failure within the resin matrix. The ILRC suffered from a pronounced decrease in FS as well as in FFL due to a constant ion-leaching and macroscopic crack growth. CO failed over time due to resin-filler interface cracking. The GIC exhibited improved mechanical performance over time due to a post-hardening mechanism. The results reveal the necessity for substantial preclinical evaluation of direct restorative materials. The material parameters under investigation are capable of predicting clinical performance over time.

The effect of pre-treatment of composite inlays on bonding performance between a resin composite inlay and a luting composite has not been fully studied. The aim of the present study was to evaluate the influence of three different pre-treatment modes on fatigue bond strength and marginal adaptation. One hundred twenty resin composite discs (Tetric Ceram) were made as simulated inlays and randomly assigned to four groups (n=30): Without treatment (WT), hydrofluoric acid etching for 15 s + silanating (HF), roughening with a silicon carbide bur (SC), and silica coating + silanating (CO). Luting composite cylinders (Variolink II low) were bonded to the discs using Heliobond, and after 24 h in water at 37 degrees C, quasistatic shear bond strengths (n=l) and fatigue bond strengths (n=20; 5,000 cycles) were measured. Thirty-two third molars received occlusomesial Class II cavities (n=8), and direct resin composite inlays were luted with identical methods and materials. Before and after thermomechanical loading (100,000x50 N, 2,500 x +5 degrees C/+55 degrees C), replicas were made and examined (SEM, x200). CO and SC exhibited significantly higher bond strengths and adhesive fatigue limits than HF and WT (P0.05). After thermomechanical loading, CO (98% continuous margin) and SC (95% continuous margin) demonstrated that they provide significantly more fatigue resistance than HF (88%).

The resin composite Ariston pHc (pHc means pH control) was introduced as an alternative for fast amalgam replacement. The aim of the present study was to evaluate clinically the behaviour of this non-bonded resin composite material, promising the release of fluoride, calcium, and hydroxy ions, in comparison to a bonded resin composite (Solitaire I) in class I and II cavities. Ninety-nine cavities in 31 patients were restored in a controlled prospective clinical study. Fifty fillings were placed with Ariston pHc as per the manufacturer's instructions, i.e. neither with enamel etching nor with the use of rubber dam. The same patients received 49 Solitaire I restorations totally bonded with Solidbond using rubber dam. At baseline, after 6 months, and after 12 months, two investigators given the same instructions examined the restorations, according to modified USPHS codes and criteria. Forty selected restorations (20 Ariston, 20 Solitaire) were additionally analysed via replicas, using a stereo light microscope (SV 11, Zeiss, Germany) at 130× magnification. After 12 months, 95 restorations were rated clinically acceptable (6% failure rate for Ariston pHc; 2% for Solitaire). Statistically significant differences were computed for both materials regarding the criterion "filling integrity". Further statistically significant deterioration for Ariston pHc between the three evaluations has been detected for the criteria "tooth integrity" (enamel cracks) and "marginal adaptation" (gap formation/Friedman 2-way ANOVA; p

The aim of this in vitro study was to compare quasistatic and cyclic fatigue dentin bond strength of modern adhesive systems representing different generations. One hundred and fifty cavities were made in discs of freshly extracted human third molars and filled with direct resin composite restorations. Dentin adhesives of different generations (SY = Syntac Classic, multi-step system with self-etching primer; SE = Syntac Classic with additional phosphoric acid etching prior to application of the self-etching primer; SB = Scotchbond Multi-Purpose Plus, multi-step system with total etching; PE = PrimeBond 2.1, single-step system with and without [PB] total etching) were used in combination with one hybrid composite. After 21 days of storage, 10 specimens for each adhesive system were subjected to thermocycling (1150 cycles) for 24 h and were afterwards debonded in a push-out test. Another 20 specimens were tested with cyclic fatigue according to the staircase method with 5000 cycles for each specimen. Static and cyclic push-out bond strengths, respectively, for each group were (MPa): SY 16.9 +/- 0.9 and 14.2 +/- 1.7, SE 17.5 +/- 1.8 and 14.8 +/- 3.4, SB 18.5 +/- 1.7 and 13.9 +/- 2.1, PB 14.6 +/- 2.2 and 7.2 +/- 2.4, PE 13.4 +/- 2.2 and 6.8 +/- 1.8. Both quasistatic and dynamic bond strengths revealed better values for the multi-step systems (P0.05). All adhesive systems tested revealed a significant fatigue behaviour which was more pronounced for the one-bottle system with a decrease of about 50% independent of additional dentin etching.