The effect of maximum bite force on marginal bone loss of mini-implants supporting a mandibular overdenture: a randomized controlled trial.

OBJECTIVES: To evaluate the effect of maximum bite force (mBF) on marginal bone loss (MBL) around mini-implants in edentulous patients wearing mandibular overdentures with two retention systems: ball and bar. MATERIAL AND METHODS: Forty-five totally edentulous patients were selected from a public health center. All of them received two mini-implants (1.8 x 15 mm; Sendax) in the anterior mandible using a minimally invasive technique. A single randomization was performed to allocate the patients in two groups. Group I (n=22) received two single ball-type mini-implants and Group II (n=23) received two mini-implants splinted with a prefabricated bar. The mBF was recorded using a press-sensitive sheet Dental Prescale (Fuji) and MBL using standardized radiographs of each mini-implant at the baseline and 5, 7, 10, and 15 months after surgery; the values were compared between groups. RESULTS: Two members of Group I failed to complete the study, decreasing the number of participants to 20. There was no relationship between the mBF and the MBL of the mini-implants (Spearman's rhor(s)=0.147; P=0.378). At the 15-month follow-up, the average mBF for Group I (ball) was 247.53 +/- 132.91 N and that of Group II (bar) only 203.23 +/- 76.85 N (Mann-Whitney test; P=0.586). The MBL values were also higher for Group I (1.40 +/- 1.02 mm) than Group II (0.84 +/- 0.66 mm) during the entire 15-month follow-up period (Mann-Whitney test; P=0.077). CONCLUSIONS: No relationship was found between mBF and MBL for patients wearing overdentures retained on mini-implants using bar or ball attachment systems.

rasiRNAs, DNA damage, and embryonic axis specification.

Drosophila repeat-associated small interfering RNAs (rasiRNAs) have been implicated in retrotransposon and stellate locus silencing. However, mutations in the rasiRNA pathway genes armitage, spindle-E, and aubergine disrupt embryonic axis specification, triggering defects in microtubule organization and localization of osk and grk mRNAs during oogenesis. We show that mutations in mei-41 and mnk, which encode ATR and Chk2 kinases that function in DNA damage signal transduction, dramatically suppress the cytoskeletal and RNA localization defects associated with rasiRNA mutations. In contrast, stellate and retrotransposon silencing are not restored in mei-41 and mnk double mutants. We also find that armitage, aubergine, and spindle-E mutations lead to germ-line-specific accumulation of gamma-H2Av foci, which form at DNA double-strand breaks, and that mutations in armi lead to Chk2-dependent phosphorylation of Vasa, an RNA helicase required for axis specification. The Drosophila rasiRNA pathway thus appears to suppress DNA damage in the germ line, and mutations in this pathway block axis specification by activating an ATR/Chk2-dependent DNA damage response that disrupts microtubule polarization and RNA localization.

[Maxillofacial injuries in polytrauma. Results of a follow-up study]. / Kiefer-Gesichtsverletzungen beim Polytrauma. Ergebnisse einer Nachuntersuchung.

Evaluation of the clinical charts of 86 patients with polytrauma, accompanied by fractures of the facial skull, and reexamination of 48 of these patients showed that with adequate therapy the concomitant lacerations do not influence the results of orofacial treatment. The complexity of the anatomical structures and of their functions necessitates early, differentiated, and interdisciplinary treatment. The special aspects and problems are presented and discussed.