Tierexperimentelle Untersuchungen des frühen Osseointegrationsverhaltens von zylindrischen gegenüber konischen Implantaten in vivo

Diese Studie untersucht das frühe Einheilverhalten zweier Implantatsysteme im Bezug auf das Implantatdesign. Es handelt sich um konische, zur Sofortbelastung konzipierte Implantate. Als Referenzgruppe dient das zylindrische ITI® Implantat. Dazu wurden 30 Implantate je Gruppe in die Tibiaknochen von Göttingerminischweinen inseriert. Es wurden fotographische, histologische, rasterelektronenmikroskopische und histomorphometrische Untersuchungen durchgeführt. Die ITI-Implantate wiesen im Bereich der Spongiosa eine etwas dichtere Knochenapposition auf. Das knöcherne Interface bezog bei den konischen Implantaten den krestalen Anteil mit ein. Bei den zylindrischen Implantaten zeigte sich nach 7 und 28 Tagen ein schmaler Spalt nicht ossifizierten Gewebes. Die Ergebnisse zeigen positive Ergebnisse im Bezug auf das frühe Osseointegrationsverhalten beider Implantatsysteme. Sie sprechen weiterhin für eine Abhängigkeit der Ausformung des krestalen periimplantären Knochens vom Implantatdesign

Effectiveness of maxillary protraction using a hybrid hyrax-facemask combination: A controlled clinical study

OBJECTIVE: To evaluate the treatment effects of a hybrid hyrax-facemask (FM) combination in growing Class III patients. MATERIAL AND METHODS: A sample of 16 prepubertal patients (mean age, 9.5 ± 1.6 years) was investigated by means of pre- and posttreatment cephalograms. The treatment comprised rapid palatal expansion with a hybrid hyrax, a bone- and toothborne device. Simultaneously, maxillary protraction using an FM was performed. Mean treatment duration was 5.8 ± 1.6 months. The treatment group was compared with a matched control group of 16 untreated Class III subjects. Statistical comparisons were performed with the Mann-Whitney U-test. RESULTS: Significant improvement in skeletal sagittal values could be observed in the treatment group over controls: SNA: 2.4°, SNB: −1.7°, Co-Gn: −2.3 mm, Wits appraisal: 4.5 mm. Regarding vertical changes, maintenance of vertical growth was obtained as shown by a small nonsignificant increase of FMA and a small significant decrease of the Co-Go-Me angle. CONCLUSIONS: The hybrid hyrax-FM combination was found to be effective for orthopedic treatment in growing Class III patients in the short term. Favorable skeletal changes were observed both in the maxilla and in the mandible. No dentoalveolar compensations were found

Role of anatomical sites and correlated risk factors on the survival of orthodontic miniscrew implants:a systematic review and meta-analysis

Abstract Objectives The aim of this review was to systematically evaluate the failure rates of miniscrews related to their specific insertion site and explore the insertion site dependent risk factors contributing to their failure. Search methods An electronic search was conducted in the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Knowledge, Scopus, MEDLINE and PubMed up to October 2017. A comprehensive manual search was also performed. Eligibility criteria Randomised clinical trials and prospective non-randomised studies, reporting a minimum of 20 inserted miniscrews in a specific insertion site and reporting the miniscrews’ failure rate in that insertion site, were included. Data collection and analysis Study selection, data extraction and quality assessment were performed independently by two reviewers. Studies were sub-grouped according to the insertion site, and the failure rates for every individual insertion site were analysed using a random-effects model with corresponding 95% confidence interval. Sensitivity analyses were performed in order to test the robustness of the reported results. Results Overall, 61 studies were included in the quantitative synthesis. Palatal sites had failure rates of 1.3% (95% CI 0.3–6), 4.8% (95% CI 1.6–13.4) and 5.5% (95% CI 2.8–10.7) for the midpalatal, paramedian and parapalatal insertion sites, respectively. The failure rates for the maxillary buccal sites were 9.2% (95% CI 7.4–11.4), 9.7% (95% CI 5.1–17.6) and 16.4% (95% CI 4.9–42.5) for the interradicular miniscrews inserted between maxillary first molars and second premolars and between maxillary canines and lateral incisors, and those inserted in the zygomatic buttress respectively. The failure rates for the mandibular buccal insertion sites were 13.5% (95% CI 7.3–23.6) and 9.9% (95% CI 4.9–19.1) for the interradicular miniscrews inserted between mandibular first molars and second premolars and between mandibular canines and first premolars, respectively. The risk of failure increased when the miniscrews contacted the roots, with a risk ratio of 8.7 (95% CI 5.1–14.7). Conclusions Orthodontic miniscrew implants provide acceptable success rates that vary among the explored insertion sites. Very low to low quality of evidence suggests that miniscrews inserted in midpalatal locations have a failure rate of 1.3% and those inserted in the zygomatic buttress have a failure rate of 16.4%. Moderate quality of evidence indicates that root contact significantly contributes to the failure of interradicular miniscrews placed between the first molars and second premolars. Results should be interpreted with caution due to methodological drawbacks in some of the included studies

Regularised iterative multiple correspondence analysis in multiple imputation

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