Nadine Freifrau von Maltzahn

Children’s sedentary time has increased, while daily physical activity and motor performance have decreased. We evaluated an integrated school-based exercise program by assessing changes in motor skills after one year and comparing these changes to children who did not participate. We included 303 children from five schools in this longitudinal study and assigned them either to the exercise group (EG; n = 183 with daily exercise program) or the waiting group (WG; n = 120). Motor skills were assessed at baseline and after one year. Mixed modeling was used to analyze inter-group differences of change in motor skills and to determine the effect of sex, age group, and weight status. EG improved more strongly than WG for sprint, side jumps (both p = 0.017), stand and reach (p = 0.012), and ergometry (p ≤ 0.001) when compared to WG. Girls improved more strongly in the sit-ups than boys, second graders more than fifth graders in the backwards balance and the ergometry, and non-overweight children more in the standing long jump than overweight children. The exercise program is effective in increasing motor skills and physical fitness. Girls were not disadvantaged, and overweight children profited as much as their non-overweight peers in all categories but one.

Background: Two-part abutments are typically made up of a base composed of titanium and a ceramic build-up. The long-term outcomes are affected by the mechanical durability. The purpose of the present investigation was to evaluate and compare the retention force of two-part abutment systems with titanium or titanium nitride bases—as fixed with zirconia components and with various surface treatments. Methods: A total of 60 two-part abutments were investigated—with a titanium base (n = 30) or titanium nitride coated bases (n = 30) and bonded with zirconia ceramic build-ups. The bonding surfaces were treated with aluminium oxide blasting, with an average particle size of 110 µm. The titanium bases were then pretreated with Alloy Primer or Clearfil Ceramic Primer. The ceramic build-ups were only treated with Clearfil Ceramic Primer. For twenty test specimens, no chemical pretreatment was performed. Test specimens were classified into six groups in accordance with the pretreatment (A–F; n = 10). A resin-based luting agent was employed to attach the two parts. Specimens were then subjected to artificial thermal aging (10⁴ cycles with 5 °C/55 °C). The retention force between the two parts was then investigated with a pull-off test. The findings were analyzed by ANOVA statistics. Fracture patterns were examined by electron microscopy. Results: In the absence of primer, titanium nitride coated bases gave significantly greater retention forces than other samples (p < 0.05). Chemical preconditioning with silane coupling agents did not effect on the retention force of coated bases. Conclusions: The results of the current study suggested that modifying metal surfaces by coating the base with titanium nitride not only has esthetic and biological advantages, but also enhances the mechanical properties of the adhesive bond of two-part abutments.

Objectives: The aim of this study was to evaluate volume, vitality and diversity of biofilms on the abutment materials zirconia and titanium as a function of time using an in vivo model for the biofilm formation.Materials and methods: The development of biofilms on zirconia and titanium grade 4 test specimens in the human oral cavity over time was analysed. After pretreatment, a total of 96 titanium and 96 zirconia discs were fixed on 12 composite splints, which were worn by 12 volunteers. After 6 hr, 24 hr, 3 days and 5 days, biofilms on 48 specimens of each material were analysed with confocal laser scanning microscopy (CLSM). The microbiota composition on the other 48 test specimens was examined using full‐length 16S sequence analysis. Statistical analysis was performed by SPSS and R, and level of significance was set at 0.05.Results: Confocal laser scanning microscopy analysis of the biofilms revealed significant changes in volume over time on zirconia and titanium. The material did not significantly influence the volume or live/dead ratio at the individual time points. The composition of the microbiome was influenced by the age of the biofilm, but not by the material of the test specimen. The most frequently found bacteria were Streptococcus spp., followed by Neisseria spp., Rothia spp., Haemophilus spp., Gemella spp. and Abiotrophia spp.Conclusions: On both materials, the quantity and diversity of the microbiome increased over time. Apart from a slight difference in Veillonella abundance at one time point, there were no significant differences between zirconia and titanium.

Freifrau von Maltzahn N, et al. J Adv Prosthodont. 2020 Apr;12(2):100-106. https://doi.org/10.4047/jap.2020.12.2.100

Objectives: Two‐part abutments consist of titanium base and ceramic coping. Their long‐term success is largely determined by the mechanical stability. The aim of the present study was to investigate the retention forces of two‐part implant abutments. The study included zirconia and lithium disilicate ceramics copings, with different surface treatments and resin‐based luting agents.Material and Methods: The analysis of retention forces was based on a total of 70 test specimens. Seven surface modifications and three resin‐based luting agents were employed for the bonding of components in the seven groups (n = 70). All surfaces of titanium bases—except for a control—were pretreated with aluminum oxide blasting, either alone or in combination with surface activating primers. Surfaces of ceramic copings were also treated mechanically by sandblasting, either alone or with acid etching or different primers. All specimens underwent thermal aging (10⁴ cycles, 5°C/55°C). The retention forces between the two parts were measured with a pull‐off test. The results were analyzed by two‐way ANOVA statistics. Fracture patterns were evaluated by light and scanning electron microscopy.Results: No mechanical pretreatment of the titanium (group 2) base resulted in the lowest retention. The combination with Monobond plus leads to the highest pull‐off forces for both ceramic materials.Conclusions: Surface modifications and resin‐based agents influence the retention of components of two‐part abutments. Lithium disilicate ceramic copings reached comparable results of retention to the typically used zirconia copings.

Einführung Ziel dieser Studie war es, bei 5 verschiedenen Implantatsystemen mit Innen- oder Außenverbindung die Mikrospaltgröße zwischen Implantat und Abutment vor und nach mechanischer Belastung im Mikro-CT zu untersuchen. Material und Methode Die Probekörper wurden in einer zylindrischen Form in Polyurethan eingebettet. Die entsprechenden Abutments wurden im Anschluss mit Drehmoment laut Herstellerangaben fixiert. Die Probekörper wurden mit 1 × 10⁶ Zyklen im Kausimulator mit einer Kraft von 200 N mechanisch belastet. Von jedem Implantat wurden vor und nach der Belastung Aufnahmen im Mikro-CT bei einer Auflösung von 2 µm angefertigt und hinsichtlich einer Veränderung der Mikrospaltgröße an der Fügefläche untersucht. Ergebnisse Unter den Belastungsbedingungen von 200 N konnte bei einem der Implantatsysteme mit Außenverbindung eine Veränderung der Fügestelle zwischen Implantat und Abutment beobachtet werden, keine Veränderung wurde bei den Implantatsystemen mit Innenverbindung sowie mit der zweiten untersuchten Außenverbindung festgestellt. Schlussfolgerung Mechanische Belastungen können die Mikrospaltgröße zwischen Implantat und Abutment beeinflussen. Der Verbindungstyp der Komponenten scheint dabei einen entscheidenden Einfluss auf die Größe des Fügespalts zu haben. Introduction The aim of the study was to compare the microgap-size of five implant systems with flat-top or conical interfaces with and without mechanical loading with micro-CT imaging. Material and Methods One implant each was embedded with polyurethane resin in a cylindrical form. The corresponding abutments were fixed with the torque recommended by the manufacturer. The specimens were loaded with 1 × 10⁶ cycles in a chewing simulator. With a load of 200 N micro-CT images were recorded before and after the mechanical loading. Results The mechanical loading with 200 N resulted in an increase of the microgap between implant and abutment for one implant system with flat-top interface. Implant systems with conical interface and the other investigated flat-top interface showed no change. Conclusion Mechanical loading can have an impact on the microgap between implant and abutment. The type of implant-abutment connection seems to be relevant for the size of the microgap.

BackgroundThe aim of the study was to evaluate the antibacterial effect of a drug releasing poly (3-hydroxybutyrate) (P(3HB)) implant coating in comparison to pure titanium onMethodsTitanium discs were coated with P(3HB) containing 5% (w) and 10% (w) of metronidazole, either with and without a P(3HB) topcoat. The biofilm formation was evaluated after 1, 4 and 9 days in a dynamic flow chamber system. Microbial adherence was quantified by determination of bacterial surface coverage.ResultsThe evaluated formulations of P(3HB)/metronidazole showed an antibacterial effect especially in the first 24 h. Prolonged incubation for 9 days showed reduced bacterial adhesion only on polymer coatings loaded with 10% (w) of metronidazole both with and without topcoat.ConclusionsThe evaluated coating formulations can provide protection from an

Die Aufrechterhaltung eines gesunden periimplantären Gewebes zählt zu einem der wichtigsten Faktoren für den Langzeiterfolg für dentale Implantate. Die Erkrankungen des periimplantären Gewebes nehmen durch die steigende Anzahl von Implantatversorgungen deutlich zu und lassen sich klinisch durch Symptome wie Schmerzen, Schwellung, Rötung, Blutung auf Sondieren, Attachmentverlust, Pusaustritt sowie röntgenologisch durch einen Rückgang des umliegenden Knochens erkennen. Therapeutisch lässt sich eine periimplantäre Entzündung auf verschiedene Arten behandeln: Dazu zählen die mechanische und systemische Therapie sowie der Einsatz eines Lasers. Da die mechanische Entfernung des Biofilms auf Implantatoberflächen am effektivsten zu sein scheint, sollte diese immer Bestandteil der Therapie sein. Ohne eine adäquate Compliance des Patienten bezüglich der häuslichen Mundhygiene ist jedoch jeder therapeutische Ansatz meist erfolglos.

Over the years, there has been a strong consensus in dentistry that at least two implants are required to retain a complete mandibular denture. It has been shown in several clinical trials that one single median implant can retain a mandibular overdenture sufficiently well for up to 5 years without implant failures, when delayed loading was used. However, other trials have reported conflicting results with in part considerable failure rates when immediate loading was applied. Therefore it is the purpose of the current randomized clinical trial to test the hypothesis that immediate loading of a single mandibular midline implant with an overdenture will result in a comparable clinical outcome as using the standard protocol of delayed loading. This prospective nine-center randomized controlled clinical trial is still ongoing. The final patient will complete the trial in 2016. In total, 180 edentulous patients between 60 and 89 years with sufficient complete dentures will receive one median implant in the edentulous mandible, which will retain the existing complete denture using a ball attachment. Loading of the median implant is either immediately after implant placement (experimental group) or delayed by 3 months of submerged healing at second-stage surgery (control group). Follow-up of patients will be performed for 24 months after implant loading. The primary outcome measure is non-inferiority of implant success rate of the experimental group compared to the control group. The secondary outcome measures encompass clinical, technical and subjective variables. The study was funded by the Deutsche Forschungsgemeinschaft (German research foundation, KE 477/8-1). This multi-center clinical trial will give information on the ability of a single median implant to retain a complete mandibular denture when immediately loaded. If viable, this treatment option will strongly improve everyday dental practice. The trial has been registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00003730 since 23 August 2012. ( http://www.germanctr.de ).