The main goal is to test the differences between the retentive capacity of fixed retainer, vacuum-formed retainer \& combination of both; and recommend the most effective protocol for retention of lower incisors crowding treated by non-extraction treatment plan
The main question is: In patients with lower incisors crowding treated by non-extraction treatment plans, what is the difference in retentive capacity between fixed retainer, vacuum formed retainer and combined bonded and vacuum retainers in maintaining corrected lower anterior segment crowding? After enrolment, each participant will have the orthodontic appliance debonded, the adhesive remnant removed and the enamel surface polished. An alginate impression will be taken to be poured into a study model which will be scanned to obtain STL files for digital models. All patients will have periodontal charting and probing depths recorded for the lower anterior segment. According to the randomization, each patient will be assigned to a group to receive the retainer. All patients will be called for follow-up after 1 week, 1 and 3 months.
Adult patients
Finished non-extraction orthodontic treatment
Full set of permanent dentition (excluding third molars).
Good oral hygiene
Systemic disease or drugs affecting periodontal health.
Smokers
Poor oral health that precludes orthodontic treatment (presence of caries, active white spots,or periodontal diseases)
Factorial
Vacuum-formed retainer
Device* After patient finishes orthodontic treatment, the fixed orthodontic appliance will be debonded; finishing and polishing of the enamel surface will be done. * An alginate impression will be taken to be poured into a working model for fabrication of the Vacuum-formed retainer; 1mm Hard vacuum sheet will be used. * The retainer will be finished and delivered to the patient. * The patient will be instructed to wear the retainer night time only and to contact us if any damage occurred to the retainers for immediate replacement; and he will be supplied with a check list to evaluate the compliance and to calculate the wearing hours. * Another alginate impression will be taken for fabrication of the study model which will later be scanned to obtain the digital model at T0; and a periodontal chart will be filled to record the periodontal status at T0 (before wearing of the retainer).
Combined Vacuum-formed and Lingual bonded retainer from canine-to-canine.
Device* A multistrand rectangular stainless steel retainer wire will be bonded to the lingual surface of the lower anterior teeth, from the canine-to-canine bonded to all six anteriors; followed by an alginate impression; the impression will be poured into a working model for fabrication of the Vacuum-formed retainer; 1mm Hard vacuum sheet will be used \& it will be finished and delivered to the patient. * The patient will be instructed to wear the Vacuum retainer night time only and to contact us if any damage occurred to the retainers for immediate replacement or rebonding of the detached parts of the bonded retainer; and will be supplied with a check list to evaluate the compliance and to calculate the wearing hours. * Another alginate impression will be taken (with the bonded retainer in place) for fabrication of the study model which will later be scanned to obtain the digital model at T0; and a periodontal chart will be filled to record the periodontal status at T0.
Lingual bonded retainer from canine-to-canine
Device* After patient finishes orthodontic treatment, the fixed orthodontic appliance will be debonded; finishing and polishing of the enamel surface will be done. * A multistrand rectangular stainless steel retainer wire will be bonded to the lingual surface of the lower anterior teeth, from the canine-to-canine bonded to all six anteriors. * The patient will be instructed to contact us if any damage occurred to the retainers for immediate replacement or rebonding of the detached parts of the retainer. * An alginate impression will be taken (with the bonded retainer in place) for fabrication of the study model which will later be scanned to obtain the digital model at T0; and a periodontal chart will be filled to record the periodontal status at T0 (at the same visit of the delivery of the bonded retainer).
The stability of the orthodontic treatment result and the degree of relapse from baseline to 6 months
The stability of the orthodontic treatment result and the degree of relapse will be measured by superimposition of the digital model at each time point on the initial model after debonding at T0.
Patient's compliance
patients' compliance will be evaluated by the check list supplied at each time point for the groups using removable retainers.
Periodontal health
Periodontal health will be monitored by a filling a periodontal chart at each time point to check the probing depth, bleeding on probing and calculus formation on the lingual surface of lower anteriors.
The integrity of the retainers
The integrity of the retainers will be evaluated based on the rate of fracture/ debonding and loss of the retainer.
Patient's satisfaction
Patients' satisfaction will be evaluated at each follow up visit, the patients in all groups will fill a questionnaire form.
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