The evidence is based on observational studies that have small sample sizes and short follow ups. Comparisons were made between before and after situations. Studies are made by the same research group.
| Reference | Study type | Population | Intervention and comparison | Outcomes | Risk of bias |
|---|---|---|---|---|---|
| «Yokoi T, Kusumoto Y, Abe Y, ym. Association betwee...»1 | Prospective Cohort | 41 patients with unilateral shortened dental arch (SDA) missing a single 2nd molar. | I: Implant-supported crown (IFPD). C: No treatment (Wait-and-see / SDA). | OHRQoL (OHIP scores), masticatory performance. | Moderate/High |
| «Watanabe H, Abe Y, Kusumoto Y, ym. Effect of treat...»2 | Clinical Study (Pre-post) | 40 patients, unilateral SDA (missing 2 adjacent molars). | I: Implant therapy (one or two implants). C: Status before treatment (SDA). | OHRQoL (OHIP), masticatory performance. | Moderate |
| Reference | Comments |
|---|---|
| «Yokoi T, Kusumoto Y, Abe Y, ym. Association betwee...»1 | Observational study, no randomization. The control group (no treatment) was small. Risk of selection bias (patients chose their treatment). |
| «Watanabe H, Abe Y, Kusumoto Y, ym. Effect of treat...»2 | Pre-post design without a separate untreated control group. Comparison made between 1 vs 2 implants and pre/post treatment. |
Results
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events (%) I | Absolute number of events (%) C | Relative effect (95% CI) |
|---|---|---|---|---|---|
| «Yokoi T, Kusumoto Y, Abe Y, ym. Association betwee...»1 | 1 study / 41 pts (22 Implant vs 19 SDA). | 1 month post-tx | OHIP scores improved significantly, mean reduction in the OHIP summary scores was 13.4 (SD13.0). |
No change in wait-and-see | p < 0.05 for improvement (before to after) |
| «Watanabe H, Abe Y, Kusumoto Y, ym. Effect of treat...»2 | 1 study / 40 pts. |
1 month post-tx | Significant OHIP improvement 63.6% of the single-unit group and 58.6% of the two-unit group showed an improvement of 6 points or more |
N/A (pre-post) | p < 0.05, Effect size d = 0.604 for all (before to after) |
| Level of evidence: Low The level of evidence is downgraded by small sample sizes, short follow-up periods, and a lack of randomization in quality-of-life studies. Although a short follow-up time limits long-term observation, it enables the minimization of confounding variables and allows for a direct pre-post comparison of the procedure itself, without the interference of potential long-term complications. |
|||||