Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Let me give you an example: Chronic rhinosinusitis (CRS) is a heterogeneous disease with an uncertain pathogenesis. Group 2 innate lymphoid cells (ILC2s) represent a recently discovered cell population which has been implicated in driving Th2 inflammation in CRS; however, their relationship with clinical disease characteristics has yet to be investigated. The aim of this study was to identify ILC2s in sinus mucosa in patients with CRS and controls and compare ILC2s across characteristics of disease. A cross-sectional study of patients with CRS undergoing endoscopic sinus surgery was conducted. Sinus mucosal biopsies were obtained during surgery and control tissue from patients undergoing pituitary tumour resection through transphenoidal approach. ILC2s were identified as CD45(+) Lin(-) CD127(+) CD4(-) CD8(-) CRTH2(CD294)(+) CD161(+) cells in single cell suspensions through flow cytometry. ILC2 frequencies, measured as a percentage of CD45(+) cells, were compared across CRS phenotype, endotype, inflammatory CRS subtype and other disease characteristics including blood eosinophils, serum IgE, asthma status and nasal symptom score. 35 patients (40% female, age 48 ± 17 years) including 13 with eosinophilic CRS (eCRS), 13 with non-eCRS and 9 controls were recruited. ILC2 frequencies were associated with the presence of nasal polyps (P = 0.002) as well as high tissue eosinophilia (P = 0.004) and eosinophil-dominant CRS (P = 0.001) (Mann-Whitney U). They were also associated with increased blood eosinophilia (P = 0.005). There were no significant associations found between ILC2s and serum total IgE and allergic disease. In the CRS with nasal polyps (CRSwNP) population, ILC2s were increased in patients with co-existing asthma (P = 0.03). ILC2s were also correlated with worsening nasal symptom score in CRS (P = 0.04).
The answer to this example can be: Are group 2 innate lymphoid cells ( ILC2s ) increased in chronic rhinosinusitis with nasal polyps or eosinophilia?
Here is why: The question is based on the following sentences from the passage (i) Group 2 innate lymphoid cells (ILC2s) {ii) In the CRS with nasal polyps (CRSwNP) population, ILC2s were increased in patients with co-existing asthma (iii) As ILC2s are elevated in patients with CRSwNP, they may drive nasal polyp formation in CRS. and (iv) They were also associated with increased blood eosinophilia

OK. solve this:
Cochrane Oral Health Group's Trials Register, CENTRAL, Medline via PubMed and EMBASE; no restrictions on language, published before February 1st 2013.", 'Observational studies reporting outcomes from irradiated and non-irradiated patients were eligible for inclusion as were randomised controlled trials (RCTs) and controlled clinical trials (CCTs) assessing irradiated patients submitted to different implant-based treatment protocols.', "Screening of titles, abstracts and full texts was by two reviewers, with disagreements resolved through discussion, consensus, or failing this by consultation with a third reviewer. Data extraction was in duplicate and attempts were made to contact authors for missing data. Risk of bias was assessed using adapted versions of the Cochrane Collaboration's tool (for RCTs and CCTs) and the Newcastle-Ottawa scale for observational studies.", 'Fifteen trials with 10,150 implants were included with 1,689 (14.3%) placed in irradiated mouths. There were 13 case series and two RCTs. three of the studies were on hyperbaric oxygen (HBO) therapy. Neither of the RCTs was rated as low risk of bias. Mean survival rates ranged from 46.3% to 98% with pooled estimates showing that implant failure was statistically significantly higher in irradiated patients compared to patients who had not undergone radiotherapy (an increase of 174%) with a risk ratio of 2.74 (95% confidence interval {CI}: 1.86, 4.05; p<0.00001). In maxillary sites, the risk ratio was 5.96 (95% CI:2.71, 13.12;p<0.00001) with the risk of loss increasing to 496%. Hyperbaric oxygen therapy did not reduce the risk of implant failure showing a risk ratio of 1.28 (95% CI:0.19, 8.82).
Answer:
Do radiotherapy associated with higher rates of dental implant loss?