Strategies for Oxygen Ecosystems in Middle-Income Countries: A Review and Case Study from Lebanon.

The COVID-19 pandemic led to a surge of critically ill patients and a sudden increase in the need for oxygen treatment worldwide. Pre-existing gaps in oxygen systems became apparent, and governments, multilateral agencies, and other partners scrambled to increase the production, supply, and use of oxygen to meet this need. The importance of an oxygen ecosystem that is appropriate for the local context became clear. This review describes strategies for oxygen ecosystems in middle-income countries, with specific experiences from Lebanon, following the authors' extensive assessment of the country's oxygen ecosystem, on behalf of the government and UNICEF. In the assessment, fifteen governmental hospitals were visited and evaluated using the UNICEF Oxygen System Planning Tool, discussions were held with key stakeholders, and documents were reviewed. An optimal oxygen ecosystem needs to take into consideration the production of oxygen and delivery to facilities, the maintenance system within facilities, and the clinical use of oxygen. Lebanon, a lower-middle income country in the Middle East, is contending with an extensive economic crisis affecting the health system. Eighteen recommendations for strengthening the oxygen ecosystem in Lebanon that are relevant for other middle-income countries include the establishment of a National Oxygen Committee, installation of additional oxygen plants, strengthened systems for maintenance and electricity supply, increased production, procurement and supply chain resilience, improved training and human resources, the use of data collection and regular information to guide the ecosystem, and integration of oxygen into the rest of the health system.

A Prospective Multicenter Study on Radiographic Crestal Bone Changes Around Dental Implants Placed at Crestal or Subcrestal Level: One-Year Findings.

PURPOSE: To compare the peri-implant radiographic crestal bone changes around implants placed at the subcrestal or crestal level. MATERIALS AND METHODS: Systemically healthy patients with at least two missing teeth requiring implant-supported fixed prosthetic restorations were enrolled in the study. Implants were randomly placed either 1 mm subcrestally or at the bone crest level. Radiographic examination was performed using the long-cone parallel technique and customized film holders. Digital periapical radiographs were obtained at the time of implant placement (T0), at the time of prosthesis delivery (T1), and 12 months (T2) after prosthetic loading. Marginal bone levels were measured at the mesial and distal aspects of each implant with digital image software. RESULTS: A total of 54 implants were present for the radiographic analysis at the 12-month follow-up. No implant showed mechanical or biologic complications throughout the follow-up period. The implant survival percentage was 100%. After 1 year, the mean bone loss was 0.711 ± 0.721 mm in the subcrestal group and 0.224 ± 0.418 mm in the crestal group. Furthermore, only the subcrestal group showed statistically significant radiographic bone resorption at the end of the follow-up. CONCLUSION: Within the limitations of this study, implants placed at the crestal level showed greater peri-implant bone stability during the 1-year follow-up. Studies with larger samples and longer follow-up are needed to confirm the results of this investigation.

Maxillary Sinus Membrane Elevation Using a Special Drilling System and Hydraulic Pressure: A 2-Year Prospective Cohort Study.

The purpose of this study was to evaluate clinical and radiologic outcomes using a newly developed device for maxillary sinus membrane elevation. Patients with a residual bone height of at least 3 mm were enrolled. Crestal sinus lift elevation and sinus graft were performed using the crestal approach sinus (CAS) kit. Graft was avoided if the residual bone crest was ≤ 2 mm less than the length of the planned implant. Outcome measures were implant and prosthesis failure, any biologic or technical complications, and marginal bone loss (MBL). A total of 35 consecutive patients underwent 49 crestal elevations of the sinus membrane. All the implants were followed for at least 2 years after placement (mean follow-up 37.3 months; range 24 to 54 months). No implants or prostheses failed during follow-up, and no membrane tears or other intraoperative or postoperative adverse events were observed. At the 2-year follow-up, mean MBL was 0.33 ± 0.24 mm (95% confidence interval: 0.08 to 0.30 mm). A total of 32 implants were placed after filling the sinus with anorganic bovine bone, while 17 implants were placed without grafting the sinus. Post-hoc analysis was performed using the sinus grafting remodeling index (SGRI) to evaluate radiographically the tissue remodeling patterns. The SGRI was statistically significantly higher when the sinus was grafted (P = .000). The CAS kit may provide a new option for minimally invasive crestal sinus surgery. Long-term randomized controlled trials with larger sample size are needed to confirm these preliminary results.

Outcome of dental implants in partially edentulous patients with and without a history of periodontitis: a 5-year interim analysis of a cohort study.

PURPOSE: To evaluate the outcome of dental implants placed in partially edentulous patients with a history of severe periodontitis (SP), moderate periodontitis (MP) and no periodontitis (NP). MATERIALS AND METHODS: Sixty-two partially edentulous patients were consecutively enrolled in this study. Patients were divided into three groups according to their initial periodontal conditions, assessed with a modified Periodontal Screening and Recording (PSR) index: 26 patients were in the SP group, 7 in the MP group, and 29 in the NP group. Patients requiring periodontal treatment were treated prior to implantation. Various dental implants and procedures were used. In the SP group 129 implants were placed, 26 were placed in the MP group, and 72 in the NP group. Outcome measures were prosthetic success, implant survival, prevalence of peri-implantitis and mean peri-implant bone level changes on periapical radiographs. RESULTS: Six patients dropped out, two from each group, at 5 years. Two implants and their prosthesis failed with peri-implantitis in one patient and two implants were successfully treated for periimplantitis in another patient in the SP group. After 5 years, patients affected by SP and MP lost on average twice the amount of peri-implant bone compared with healthy patients (2.6 mm versus 1.2 mm). This difference was highly statistically significant. CONCLUSIONS: Patients with a history of SP and MP lose more peri-implant bone than periodontally healthy patients and might be at higher risk for peri-implantitis and implant failures.

Immediate loading of dental implants placed in severely resorbed edentulous mandibles reconstructed with autogenous calvarial grafts.

OBJECTIVE: The aim of this prospective study was to present the clinical outcome of immediately loaded dental implants placed in edentulous, severely atrophied mandibles, after reconstruction with autogenous multilayered calvarial grafts. MATERIALS AND METHODS: Six patients, two males and four females, aged 40-67 years (mean: 56 years) presenting with severely atrophied edentulous mandibles (Cawood and Howell class VI), were reconstructed with multilayered calvarial bone grafts placed in the intraforaminal area of the mandible. Five to 8 months afterwards, 23 dental implants were placed in the reconstructed areas (three to four implants per patient) and immediately loaded with implant-supported overdentures. Patients were followed with clinical and radiographic controls annually. RESULTS: Recovery after the reconstruction was uneventful in all patients. All 23 implants were osseointegrated 1-3 years after the start of immediate loading. The survival and success rates of implants were 100% and 95.7%, respectively. CONCLUSION: Results from this study showed that immediate loading of dental implants placed in severely atrophied edentulous mandibles reconstructed with calvarial bone grafts is a predictable procedure, which permits a successful dental rehabilitation with a shortening of treatment times.

Immediate loading of dental implants placed in revascularized fibula free flaps: a clinical report on 2 consecutive patients.

PURPOSE: The objective of this study was to report the clinical outcome of dental implants placed in revascularized fibula flaps for the reconstruction of severely atrophied edentulous maxillae and immediately loaded with full-arch implant-supported prostheses. MATERIALS AND METHODS: Two patients, a 55-year-old woman and a 59-year-old woman, who presented with severely atrophied edentulous maxillae and local anatomy incompatible with rehabilitation with conventional complete removable dentures and insufficient bone volume for placement of implants of adequate dimensions were selected for reconstruction with revascularized fibula free flaps. Three months after the reconstructive procedure, Brånemark System dental implants (8 in the 55-year-old patient, 7 in the 59-year-old patient) were placed in the reconstructed areas and immediately loaded with implant-supported full-arch prostheses. The mean follow-up period of implants after the start of prosthetic loading was 24 months. Radiographic peri-implant bone level changes and peri-implant clinical parameters (Plaque Index, Bleeding Index, and probing depth) were evaluated. RESULTS: No implants were lost during the follow-up period. Implant survival and success rates were 100% and 93.3%, respectively. Peri-implant clinical parameters presented values consistent with those obtained for implants placed in native nonreconstructed bone and allowed to heal before loading. DISCUSSION: To the authors' knowledge, this is the first time that the successful immediate loading of implants placed in fibula free flaps for the rehabilitation of totally edentulous patients with severely resorbed maxillae or mandibles has been described. CONCLUSION: Despite the limited number of patients and the short follow-up period, immediate loading of implants placed in revascularized fibula free flaps appears to be a reliable method for the dental rehabilitation of these patients.

Implant-retained mandibular overdentures with immediate loading: a 3- to 8-year prospective study on 328 implants.

PURPOSE: The purpose of this study is to evaluate prospectively survival and success rates of implants placed in the interforaminal area of edentulous mandibles and immediately loaded with an implant-supported overdenture. MATERIALS AND METHODS: Eighty-two patients, 33 males and 49 females, aged between 42 and 87 years (mean age 58.6 yr), presenting edentulous mandibles were rehabilitated with an implant-supported overdenture in the mandible. Three hundred twenty-eight screw-type osseointegrated implants (164 Ha-Ti, Mathys Dental, Bettlach, Switzerland; 84 ITI Dental Implant System, Straumann Institute, Waldenburg, Switzerland; 40 Brånemark Conical, Nobel Biocare AB, Gothenburg, Sweden; 40 Frialoc, Friatec, AG Mannheiti, Germany), were placed in the intraforaminal area of the mental symphysis (4 implants per patient). Immediately after implant placement, a U-shaped gold or titanium bar was fabricated and implants were rigidly connected with the bar and immediately loaded with an implant-retained overdenture. Success rate of implants was evaluated clinically and radiographically every year after the loading of the prostheses according to the following parameters: (1) absence of clinical mobility of implants tested individually after bar removal, (2) absence of periimplant radiolucency evaluated on panoramic radiographs, (3) absence of pain and radiologic or clinical signs of neural lesion, and (4) periimplant bone resorption mesial and distal to each implant less than 0.2 mm after the first year of prosthetic load. RESULTS: Of 328 implants placed, 296 were followed up from a minimum of 36 months to a maximum of 96 months, with a mean follow-up of 62 months. Seven implants in 6 different patients were removed owing to loss of osseointegration, whereas 18 implants, although still osseointegrated, did not fulfill success criteria due to bone resorption > 0.2 mm/year after the first year of loading. Despite implant losses, all patients maintained their bars supporting overdentures, although in 6 patients they were supported by 3 instead of 4 implants. The only patient who lost 2 implants received 2 new implants, which survived normally. Therefore, the absolute success and survival rates were 91.6% and 97.6%, respectively, whereas the cumulative survival and success rates of implants obtained with a life table analysis were 96.1% and 88.2%, respectively. CONCLUSIONS: Results of this study seem to demonstrate that survival and success rates of immediately loaded implants placed in the intraforaminal area of the mandible and rigidly connected with a bar through an implant-supported overdenture are consistent with those reported in the international literature as far as delayed loading is concerned after 3 years of loading. After longer observation times, this study demonstrated that, while survival rates of implants and bar-supported overdentures are still consistent with results published in the international literature pertaining to delayed loading, a moderate decrease in success rates of implants was found. Nevertheless, it must be stressed that this decrease (88.8 and 90.4% after a 7- to 8-year observation period for Ha-Ti and ITI implants) is related only to two implant systems; no data are available for the other two implant systems because of the shorter follow-up period.

Immediate loading of Brånemark implants: a 24-month follow-up of a comparative prospective pilot study between mandibular overdentures supported by Conical transmucosal and standard MK II implants.

BACKGROUND: The purpose of this prospective study is to compare the long-term outcome of immediately loaded implant-retained mandibular overdentures supported by four screw-type one-piece transmucosal implants with that of four screw-type two-piece implants inserted in the interforaminal area of the mandible and rigidly connected by a U-shaped curved MATERIALS AND METHODS: A prospective pilot study was conducted with 10 patients receiving an implant-supported overdenture in the mandible. The patients were randomly assigned to two groups. In the control group (five patients), four standard Brånemark implants (MK II; Nobel Biocare AB, Gothenburg, Sweden), 3.75 mm large and at least 10 mm long, were sited anterior to the mental foramina, and four standard abutments (Nobel Biocare AB) for bar construction were immediately screwed to the implants. In the test group (five patients), four conical transmucosal implants (Nobel Biocare AB), 3.75 mm large and at least 9 mm long in the threaded part, were sited anterior to the mental foramina. Immediately after implant placement, a U-shaped gold or titanium bar was fabricated and implants were immediately loaded (within 24 h) in both groups with an implant-retained overdenture. The patients were followed up for a minimum of 24 months. Implants were evaluated at the time of immediate loading and at 12 and 24 months after prosthetic loading, with the following parameters: modified plaque index (MPI), modified bleeding index (MBI), and probing depth (PD). Periimplant bone resorption was evaluated on panoramic radiographs taken 12 and 24 months after the beginning of prosthetic loading. RESULTS: No significant differences were found between the two groups with regard to MPI, MBI, PD, and periimplant bone resorption at 12 and 24 months. The cumulative success rate of implants according to the criteria proposed by Albrektsson and colleagues was 100% in both groups after 2 years of functional loading. CONCLUSIONS: Results from this study demonstrated that the success rate for immediately loaded mandibular implants is similar to that obtained in cases of delayed loading and that there are no significant differences between results with two-piece implants and one-piece transmucosal implants.