You will be provided with the titles and abstracts of a collection of medical RCT reports studying a clinical question -- for instance, the efficacy of an intervention on some medical outcome. Please write a few sentences synthesizing the findings of these reports, which could serve as a conclusion section for a systematic review article. Your response should not include any other text. The RCT reports are below.



Title 1:
A long-term prospective evaluation of the circumferential supracrestal fiberotomy in alleviating orthodontic relapse.
Abstract 1:
This prospective study conducted during a period of nearly 15 years initially involved 320 consecutively selected cases. The primary purpose of the investigation was to statistically evaluate the efficacy of the circumferential supracrestal fiberotomy (CSF) procedure in alleviating dental relapse following orthodontic treatment. The "Irregularity Index" method of Little for measuring the malposition of teeth was used to quantitatively record the relapse of the control and CSF cases at approximately 4 to 6 years after active treatment and again at 12 to 14 years after active treatment. The differences between the mean relapses of the control and the CSF cases were highly significant at both time intervals. The surgical procedure appeared to be somewhat more effective in alleviating pure rotational relapse than in labiolingual relapse. On a long-term basis, the CSF procedure was shown to be more successful in reducing relapse in the maxillary anterior segment than in the mandibular anterior segment. Nevertheless, a significant and unpredictable variation in individual tooth movement following orthodontic treatment was observed in both the control and CSF groups. No clinically significant increase in the periodontal sulcus depth nor decrease in the labially attached gingiva of the CSF teeth was observed at 1 and 6 months following the surgical procedure.


Title 2:
Clinical comparison of a multistranded wire and a direct-bonded polyethylene ribbon-reinforced resin composite used for lingual retention.
Abstract 2:
The reliability of posttreatment canine-to-canine retention with resin composite retainers reinforced with plasma-treated woven polyethylene ribbons was compared to the reliability of directly bonded, multistranded wire retainers.
                This prospective study was based on an assessment of 20 consecutive patients (eight women and 12 men with a mean age of 22.4 years) who required a fixed canine-to-canine retainer after undergoing orthodontic treatment. The type of retainer used was randomized for each patient. A follow-up examination was carried out once every 3 months. The length of time the retainers stayed in place without resin fracture or loosening from the teeth at one or more points was evaluated. The study's endpoint was 24 months after the retainer had been bonded.
                The ribbon-reinforced retainer remained in place for an average of 11.5 months, and the multistranded wire for a mean of 23.6 months. The difference was statistically significant.
                In terms of reliability for permanently fixed orthodontic retention from canine to canine, the direct-bonded multistranded wire is superior to the plasma-treated polyethylene woven ribbon and resin retainer.


Title 3:
Comparison of occlusal contacts with use of Hawley and clear overlay retainers.
Abstract 3:
Following orthodontic treatment, an increase in the number of occlusal contacts is usually desired during retention. In this study, Hawley and clear overlay orthodontic retainers were compared relative to changes in the number of occlusal contacts. Occlusal contacts were quantified in 30 orthodontic patients at debonding, at retainer delivery, and after 3 months of retention. The paired t-test was applied to evaluate longitudinal changes in the number of and intensity of contacts. Results show that with the Hawley retainer there was a significant increase in occlusal contacts on posterior teeth and no change on anterior teeth. With the clear overlay retainer there was no significant change in either posterior or anterior contacts during retention. The retentive capacities of the two retainers differ: the Hawley retainer allows relative vertical movement (settling) of the posterior teeth while the clear overlay retainer holds teeth in their debanding position.


Title 4:
A 3-year follow-up study of various types of orthodontic canine-to-canine retainers.
Abstract 4:
The present study was performed to test the tendency for plaque and calculus build-up along the wire of different types of bonded orthodontic canine-to-canine retainers, whether the presence of such retainers causes any damage to the teeth involved, the failure rate of the retainers, and any changes in incisor alignment during a 3-year period of retention. The four test groups received either retainers made of thick plain wire bonded only to the canines (n = 11); thick spiral wire bonded only to the canines (n = 13); thin, flexible spiral wire bonded to each tooth (n = 11); or removable retainers (n = 14). Accumulation of plaque and calculus along the gingival margin, gingival inflammation and probing attachment level were scored in lingual areas from canine to canine at the time of fixed appliance removal and again 3 years after retainer insertion. Incisor irregularity was measured on plaster models made at the same time periods. Accumulation of plaque and calculus and development of caries along the wire were scored at follow-up. Retainer failures were recorded whenever they occurred. The results revealed no intergroup differences in changes between baseline and follow-up examinations or status along the retainer wire for any of the variables. Gingival inflammation and plaque accumulation were scored less frequently after 3 years in retention than at the time of debonding. No signs of caries were seen adjacent to the wire. Failures were observed of one, four and three of the fixed retainer types, respectively. These patients showed a greater increase in incisor irregularity than the other patients.


Title 5:
Short-term effects of fiberotomy on relapse of anterior crowding.
Abstract 5:
The effects of fiberotomy were evaluated in alleviating dental relapse of incisors after orthodontic treatment. The study sample consisted of 23 patients with crowded maxillary and mandibular incisors before orthodontic treatment. The amount of initial crowding was determined according to Little's irregularity index. Fiberotomy procedures were performed on 11 of the patients 1 week before debonding. The other 12 subjects served as the control group. All patients wore Hawley retainers. Lateral cephalometric headfilms and dental casts of the patients were taken at the beginning (T1) and at the end (T2) of treatment, 6 months into the retention phase (T3), and 1 year after orthodontic treatment (T4). Significant increase of irregularity index was noted in the control group at T3 and T4 for both maxillary and mandibular anterior segments (P <.05, P <.01). Meanwhile, in the group where circumferential supracrestal fiberotomy was performed, no significant increase of the irregularity index was noted.
There are insufficient research data on which to base our clinical practice on retention at present. There is an urgent need for high quality randomised controlled trials in this crucial area of orthodontic practice.