Smoking, Radiotherapy, Diabetes and Osteoporosis as Risk Factors for Dental Implant Failure: A Meta-Analysis

<div><p>Background</p><p>There are conflicting reports as to the association between smoking, radiotherapy, diabetes and osteoporosis and the risk of dental implant failure. We undertook a meta-analysis to evaluate the association between smoking, radiotherapy, diabetes and osteoporosis and the risk of dental implant failure.</p><p>Methods</p><p>A comprehensive research on MEDLINE and EMBASE, up to January 2013, was conducted to identify potential studies. References of relevant studies were also searched. Screening, data extraction and quality assessment were conducted independently and in duplicate. A random-effects meta-analysis was used to pool estimates of relative risks (RRs) with 95% confidence intervals (CIs).</p><p>Results</p><p>A total of 51 studies were identified in this meta-analysis, with more than 40,000 dental implants placed under risk-threatening conditions. The pooled RRs showed a direct association between smoking (n = 33; RR = 1.92; 95% CI, 1.67–2.21) and radiotherapy (n = 16; RR = 2.28; 95% CI, 1.49–3.51) and the risk of dental implant failure, whereas no inverse impact of diabetes (n = 5; RR = 0.90; 95% CI, 0.62–1.32) on the risk of dental implant failure was found. The influence of osteoporosis on the risk of dental implant failure was direct but not significant (n = 4; RR = 1.09; 95% CI, 0.79–1.52). The subgroup analysis indicated no influence of study design, geographical location, length of follow-up, sample size, or mean age of recruited patients.</p><p>Conclusions</p><p>Smoking and radiotherapy were associated with an increased risk of dental implant failure. The relationship between diabetes and osteoporosis and the risk of implant failure warrant further study.</p></div

Forest plot of studies with dental implant failure risk for patients with radiotherapy versus non-smoking.

<p>The combined Relative risks (RR) and 95% confidence intervals (CIs) were calculated using the random-effects model.</p

Study Characteristics (DIABETES).

<p>CON = control group, that is non-diabetes group; STY = study group, that is diabetes group; F = Female; Mand. = mandible; Max. = maxilla; Retro = retrospective study; Prospec = prospective study; yr = year; m = month; NA = not available; Local = local bone; Grafted = grafted bone; FC = failure implant number of Control Group; FS = failure implant number of Study Group; QS = quality assessment score.</p

Flow Diagram of Screened and Included Papers.

<p>Flow Diagram of Screened and Included Papers.</p

Study Characteristics (OSTEOPOROSIS).

<p>CON = control group, that is non-osteoporosis group; STY = study group, that is osteoporosis group; F = Female; Mand. = mandible; Max. = maxilla; Retro = retrospective study; Prospec = prospective study; yr = year; m = month; NA = not available; Local = local bone; Grafted = grafted bone; FC = failure implant number of Control Group; FS = failure implant number of Study Group; QS = quality assessment score.</p

Study Characteristics (SMOKING).

<p>CON = control group, that is non-smoking group;STY = study group, that is smoking group; F = Female; Mand. = mandible; Max. = maxilla; Retro = retrospective study; Prospec = prospective study; yr = year; m = month; NA = not available; Local = local bone; Grafted = grafted bone; FC = failure implant number of Control Group; FS = failure implant number of Study Group; QS = quality assessment score.</p

Study Characteristics (RADIOTHERAPY).

<p>CON = control group,that is non-radiotherapy group; STY = study group, that is radiotherapy group; F = Female; BP = before placement; AP = after placement; Mand. = mandible; Max. = maxilla; Retro = retrospective study; Prospec = prospective study; yr = year; m = month; NA = not available,; Local = local bone; Grafted = grafted bone; FC = failure implant number of Control Group; FS = failure implant number of Study Group; QS = quality assessment score.</p

Forest plot of studies with dental implant failure risk for smoking versus non-smoking patients.

<p>The combined Relative risks (RR) and 95% confidence intervals (CIs) were calculated using the random-effects model.</p

Forest plot of studies with dental implant failure risk for patients with osteoporosis versus non-osteoporosis.

<p>The combined Relative risks (RR) and 95% confidence intervals (CIs) were calculated using the random-effects model.</p

Subgroup analysis to investigate differences between studies included in meta-analysis.

<p>Subgroup analysis to investigate differences between studies included in meta-analysis.</p