Single versus splinted short implants at sinus augmented sites: A systematic review and meta-analysis.

OBJECTIVE: This review primarily evaluated the success, survival and failure rates of implants shorter than 10 mm restored with single-unit or splinted fixed dental prostheses in maxillary sinus augmented sites. MATERIAL AND METHODS: Two reviewers independently performed the systematic search of electronic databases, including MEDLINE, EMBASE and CENTRAL, up to September 2019 with no language restriction. A supplemental hand search consisted of screening 13 journals. The inclusion criteria were: primary studies reporting implant, prosthetic and patient-reported outcome measures (PROMs) of extra-short and short implants placed in conjunction with sinus floor elevation in partially dentate patients, restored with single- and splinted-crowns for direct comparison, with a minimal 1-year follow-up. Weighted arithmetic mean (WAM) of the implant survival was performed according to the type of prosthesis. This was confirmed by using Review Manager software to perform meta-analysis. RESULTS: Two observational studies reporting on 106 tapered, press-fit, sintered porous-surfaced implants with a length ranging from 5 mm to 9 mm were included in this systematic review. Of these, 20 and 86 implants were restored with single and splinted prostheses, respectively. The risk ratio (RR) was 1.16 (95% CI: .31-4.30, p = .58, I² = 0%) for individually restored implants failure when compared to splinted implants, indicating that short dental implants restored with single crowns could have a 16% higher possibility of failure if compared to implants with splinted crowns. The heterogeneity value was not statistically significative (p = .58). No statistical difference in the implant survival rate of the two types of analysed prostheses was observed after WAM (p= .923). The level of evidence for the included studies ranged from low (4) to fair (2B). CONCLUSION: Similar clinical outcomes up to a 9-year follow-up were observed in single and splinted porous-surfaced implants shorter than 10 mm located in sites with sinus lift. However, the conclusion shall be interpreted with caution due to the level of evidence and limited number of included studies included in this systematic review.

An iron corrosion-assisted H2-supplying system: a culture method for methanogens and acetogens under low H2 pressures.

H2 is an important fermentation intermediate in anaerobic environments. Although H2 occurs at very low partial pressures in the environments, the culture and isolation of H2-utilizing microorganisms is usually carried out under very high H2 pressures, which might have hampered the discovery and understanding of microorganisms adapting to low H2 environments. Here we constructed a culture system designated the "iron corrosion-assisted H2-supplying (iCH) system" by connecting the gas phases of two vials (one for the iron corrosion reaction and the other for culturing microorganisms) to achieve cultures of microorganisms under low H2 pressures. We conducted enrichment cultures for methanogens and acetogens using rice paddy field soil as the microbial source. In the enrichment culture of methanogens under canonical high H2 pressures, only Methanobacterium spp. were enriched. By contrast, Methanocella spp. and Methanoculleus spp., methanogens adapting to low H2 pressures, were specifically enriched in the iCH cultures. We also observed selective enrichment of acetogen species by the iCH system (Acetobacterium spp. and Sporomusa spp.), whereas Clostridium spp. predominated in the high H2 cultures. These results demonstrate that the iCH system facilitates culture of anaerobic microorganisms under low H2 pressures, which will enable the selective culture of microorganisms adapting to low H2 environments.

Performance of a repair service set for the retrieval of fractured abutment screws: a pilot in vitro study.

PURPOSE: To report the success of a repair service set for the retrieval of fractured screws and to compare three clinical assessments to an in vitro assessment to verify the completeness of removal of the fractured screws. MATERIALS AND METHODS: Twelve clinicians were asked to remove fractured implant abutment screws from prepared specimens by means of a repair service set. The completeness of the removal of any abutment screw material was measured by the fit of an impression post, a dental surgery microscope, and the use of an elastomeric impression material. RESULTS: After the participants attempted to remove the fractured screw with the repair service set, 100%, 83.3%, 66.7%, and 75% of the fractured screws were considered successful in the impression post, dental surgery microscope, silicone replica, and stereomicroscope assessments, respectively. CONCLUSION: The retrieval of fractured screws succeeded in 75% of the cases. The silicone replica technique and the dental surgery microscope had similar diagnostic values to the stereoscopic microscope assessment.

Computer programme to assess mandibular cortex morphology in cases of medication-related osteonecrosis of the jaw with osteoporosis or bone metastases.

PURPOSE: The purpose of this study was to evaluate the morphology of the mandibular cortex in cases of medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis or bone metastases using a computer programme. MATERIALS AND METHODS: Fifty-four patients with MRONJ (35 with osteoporosis and 19 with bone metastases) were examined using panoramic radiography. The morphology of the mandibular cortex was evaluated using a computer programme that scanned the mandibular inferior cortex and automatically assessed the mandibular cortical index (MCI) according to the thickness and roughness of the mandibular cortex, as follows: normal (class 1), mildly to moderately eroded (class 2), or severely eroded (class 3). The MCI classifications of MRONJ patients with osteoporosis or bone metastases were evaluated with the Pearson chi-square test. In these analyses, a 5% significance level was used. RESULTS: The MCI of MRONJ patients with osteoporosis (class 1: 6, class 2: 15, class 3: 14) tended to be higher than that of patients with bone metastases (class 1: 14, class 2: 5, class 3: 0) (P=0.000). CONCLUSION: The use of a computer programme to assess mandibular cortex morphology may be an effective technique for the objective and quantitative evaluation of the MCI in MRONJ patients with osteoporosis or bone metastases.

Enhancement of methanogenesis by electric syntrophy with biogenic iron-sulfide minerals.

Recent studies have shown that interspecies electron transfer between chemoheterotrophic bacteria and methanogenic archaea can be mediated by electric currents flowing through conductive iron oxides, a process termed electric syntrophy. In this study, we conducted enrichment experiments with methanogenic microbial communities from rice paddy soil in the presence of ferrihydrite and/or sulfate to determine whether electric syntrophy could be enabled by biogenic iron sulfides. Although supplementation with either ferrihydrite or sulfate alone suppressed methanogenesis, supplementation with both ferrihydrite and sulfate enhanced methanogenesis. In the presence of sulfate, ferrihydrite was transformed into black precipitates consisting mainly of poorly crystalline iron sulfides. Microbial community analysis revealed that a methanogenic archaeon and iron- and sulfate-reducing bacteria (Methanosarcina, Geobacter, and Desulfotomaculum, respectively) predominated in the enrichment culture supplemented with both ferrihydrite and sulfate. Addition of an inhibitor specific for methanogenic archaea decreased the abundance of Geobacter, but not Desulfotomaculum, indicating that Geobacter acquired energy via syntrophic interaction with methanogenic archaea. Although electron acceptor compounds such as sulfate and iron oxides have been thought to suppress methanogenesis, this study revealed that coexistence of sulfate and iron oxide can promote methanogenesis by biomineralization of (semi)conductive iron sulfides that enable methanogenesis via electric syntrophy.