Table 2.
Summary of Characteristics and Results of the Included Studiesa
| Author/Country/ Year/Study Design |
Artun et al.21/United States/1997/RCT |
Stormann and Ehmer22/Germany/2002/RCT |
Al-Nimri et al.23/Jordan/2009/Non-RCT |
Steinnes et al.24/Norway/2017/ Non-RCT |
Schutz-Frazon et al.25/Sweden /2017/ Non-RCT |
|
| Sample | Source | Department of Orthodontics, University of Washington, Seattle, Wash | Department of Orthodontics, University of Münster, Germany | Department of Orthodontics, Jordan University of Science and Technology, Jordan | Public Dental Service Competence Centre of Northern Norway, Tromsø, Norway | Department of Orthodontics, Institute for Postgraduate Dental Education, Jonkoping, Sweden |
| n | 49 n = 11: thick plain wire (0.032 inch) bonded only to the canines n = 13: thick spiral wire (0.032 inch) bonded only to the canines n = 11: thin (0.205-inch) flexible spiral wire bonded to each tooth in the segment n = 14: removable retainers | 98 n = 36: twisted wire (0.0215 inch) bonded to each tooth in the segment n = 30: twisted wire (0.0195 inch) bonded to each tooth in the segment n = 32: canine-and-canine prefabricated retainer | 62 n = 31: multistrand lower retainers bonded to all six teeth n = 31 plain wire retainers bonded only in canines | 60 lower fixed retainers: bonded to all six teeth or only canines | 64 n = 28: plain wire (0.028 inch) retainers bonded only in canines n = 36: multistrand (0.0195 inch) lower retainers bonded in all six teeth | |
| Age | Adults and adolescents | 13–17 y | 19.97–20.23 y | 25 y | 12. –13.2 y | |
| Follow-up, y | 3 | 2 | 1 | 8 | 9 | |
| Assessment | Stability | Irregularity Index | Irregularity Index | Irregularity Index | Irregularity Index and PAR index | Irregularity Index |
| Results | Stability | No difference between groups on the alignment of incisors (P = .18) | The relapse rate was higher among retainers bonded only in canines (P < .001) | The retainers bonded only to canines presented a higher than those bonded in all six teeth (P = .002) | No difference among groups (P = .62) | No difference among groups (P = .05) |
| Breakages | 27.3% of retainers bonded to all teeth 20.4% of retainers bonded only in canines: 30.4% in twisted archwire and 9.1% in plain archwire | The retainers bonded in all six teeth (0.0215) presented a higher rate of breakages (53%), followed by the 0.0195 retainers (29%). The retainers bonded only to the canines presented a rate of 18%; P < .001 | No difference among groups (P > .05) | — | No difference among groups (P > .05) | |
a
RCT indicates randomized controlled trial; Non-RCT, non–randomized controlled trial.