Study | Lee and Mills 2009 [39] | Taner and Aksu 2012 [40] | |
---|---|---|---|
Selection | Is the case definition adequate? | 1 | 1 |
Representativeness of the cases | 0 – not described properly | 0 – not described properly | |
Selection of Controls | 1 | 1 | |
Definition of Controls | 1 | 1 | |
Comparability | Comparability of cases and controls on the basis of the design or analysis | 1 | 2 |
The procedures of retainer bonding and follow – up were standardized. However, in some cases, not strictly defined, the procedure was modified. The number of teeth bonded to retainer differed in induvial patients. | The procedures of retainer bonding and follow – up were standardized. The same wire, adhesive and light curing unit were used in both groups. However, the additional chemical adhesive was used in indirect bonding group The patients were randomly assigned to the groups. | ||
Outcome | Ascertainment of exposure | 1 | 1 |
Same method of ascertainment for cases and controls | 1 | 1 | |
Non-Response rate | 1 | 1 | |
Total | 7 | 8 |