***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The purpose of this study was to evaluate the periodontal tissues of patients with m and ibular fixed retention for long or short periods of time . A total of 64 individuals were selected for this study using the following inclusion criteria : long-term  lingual fixed retention ; identical type of lingual fixed retainer bonded with the same material s ; no cavities , restorations , or fractures of the m and ibular anterior teeth ; absence of habits and occlusal interferences ; and canine guidance bilaterally . The result ant sample comprised 32 patients ( mean age 25 years ) who had been in retention for a mean period of 9.65 years ( range 9 - 11 years ) and an equal number retained for a period between 3 and 6 months .  Plaque , gingival , and calculus indices , probing pocket depth , marginal recession , and bone level at the m and ibular six anterior teeth were recorded for both groups . Demographic , clinical , and radiographic data were investigated with conventional descriptive statistics . Comparisons of the different variables between the two participant groups ( long- and short-term retention ) were carried out using a Mann-Whitney test for indices ( plaque , gingival , and calculus ) , and a Fisher 's exact test ( two sided ) for the remaining variables . No significant difference was found with respect to the plaque and gingival indices and bone level between the two groups . The long-term group presented higher calculus accumulation , greater marginal recession , and increased probing depth ( P < 0.05 ) . The results of this study raise the question of the appropriateness of lingual fixed retainers as a st and ard retention plan for all patients regardless of their attitude to dental hygiene . They also emphasize the importance of individual variability and cautious application of retention protocol s after a thorough consideration of issues related to the anatomy of tissues and oral hygiene Background Most orthodontists believe that fixed retainers are necessary to maintain ideal dental relationships . However , untoward side effects might result from their long-term placement . The aim of this study was to evaluate the clinical and radiographic effect of two commonly used fixed retainers on the health of the periodontium . Methods Thirty patients were r and omly divided into two groups to receive either a fiber-reinforced composite retainer or a spiral wire retainer extended on the lingual surfaces of both maxillary and m and ibular arches from canine to canine . Periapical radiographs were obtained from the patients at the time of placement of the retainers and after the 6-month period to assess the radiographic conditions of the periodontium . Clinical examination was carried out at the same two time intervals . Results Even though there were no significant differences between the two groups of study at the beginning of the trial , there were statistically significant differences after the 6-month follow-up regarding the main outcomes of the study . Nearly all indices showed to deteriorate after 6 months in the fiber-reinforced group , while in the spiral wire group , this was not the case . As for the secondary outcomes , radiographic examination did not reveal any statistically significant differences after 6 months or between the two groups . Conclusions It can be concluded that spiral wire retainers elicit less detrimental periodontal response in the short-term follow-up compared to fiber-reinforced composite retainers as revealed by the primary outcomes of the study .Trial registration Clinical Trials.gov : Abstract Background and Aim : In recent years , fixed lingual retainers have been gaining importance in relapse prevention . The aim of this prospect i ve , r and omized study was to compare different types of fixed retainers used for stabilization of the lower anterior segment with respect to detachment rate , relapse , periodontal and oral hygiene problems , as well as subjective patient discomfort . Patients and Method : Two types of fixed , customized canine-to-canine retainers ( attached to six teeth ) with wire diameters of 0.0215 ” and 0.0195 ” as well as one type of prefabricated canine- and -canine retainer ( bonded to two teeth ) were investigated in a total of 103 patients . Some retainers wer inserted under dry field conditions using a rubber dam , and the others under relatively dry conditions using cotton rolls . In addition , two types of composite , Heliosit ® and Concise ™ , were compared . Results : The canine- and -canine retainer displayed an 18 % detachment rate , a value significantly lower than the 29 % determined for the 0.0195 ” canine-to-canine retainers . The 0.0215 ” canine-to-canine retainer had the highest detachment rate ( 53 % ) . The 37 % detachment rate with dry field bonding was slightly higher than the 32 % with relatively dry field bonding . Comparison of the composites showed a significantly higher detachment rate for Heliosit ® ( 73 % ) than for Concise ™ ( 27 % ) . Plaque accumulation increased with all retainer types in the course of the study , but with no significant inter-group differences . Tooth position with canine-to-canine retainers showed a good degree of stability . The canine- and -canine retainer induced frequent relapse of incisors not bonded to the retainer . In view of their higher rate of subjective discomfort , canine- and -canine retainers were given a significantly poorer rating than their canine-to-canine counterparts . ZusammenfassungHintergrund und Ziel : In den letzten Jahren gewinnen die Lingualretainer zur Rezidivprophylaxe an Bedeutung . Ziel der Studie war es , prospektiv und r and omisiert verschiedene permanente Retainersysteme zur Stabilisierung der Unterkieferfront in Bezug auf Ablöseraten , Rezidive , parodontale und mundhygienische Probleme sowie subjektive Belastungen zu vergleichen . Patienten und Method e : Es wurden zwei an sechs Zähnen adhäsiv befestigte ( Sechspunktretainer ) der Drahtstärken 0,0215 ” und 0,0195 ” und ein konfektionierter , an zwei Zähnen befestigter Retainer ( Zweipunktretainer ) verwendet . Ein Teil der Retainer wurde unter Kofferdam eingesetzt , ein and erer unter relativer Trockenlegung mit Watterollen . Des Weiteren wurden die Komposite Heliosit ® Orthodontic und Concise ™ Orthodontic verglichen . Ergebnisse : Der Zweipunktretainer wies mit 18 % eine signifikant geringere Ablöserate auf als der Sechspunktretainer der Drahtstärke 0,0195 ” mit 29 % . Der Sechspunktretainer der Stärke 0,0215 ” hat mit 53 % die höchste Ablöserate . Die Ablösungsrate lag bei absoluter Trockenlegung mit 37 % geringfügig höher als bei relativer Trockenlegung mit 32 % . Der Vergleich der beiden Komposite ergab eine signifikant größere Ablösungsrate  für Heliosit ® ( 73 % ) gegenüber Concise ™ ( 27 % ) . Die Plaqueakkumulation nahm bei allen drei Retainertypen i m Verlauf der Studie zu ohne signifikante Unterschiede zwischen den einzelnen Retainertypen . Die Zahnstellung blieb bei den beiden Sechspunktretainern weitgehend stabil . Bei dem Zweipunktretainer kam es gehäuft zu Rezidiven der nicht gefassten Schneidezähne . Zweipunktretainer schnitten durch die höhere Angabe subjektiver Beschwerden bei der Fragebogenauswertung zur Patientenbelastung signifikant schlechter ab als Sechspunktretainer BACKGROUND Different types and diameters of wire are used in bonded lingual retainers . Some clinicians bond a small diameter multistr and wire to each tooth , while other clinicians bond a large diameter wire to the lingual surfaces of the lower canines . AIM To compare the gingival health , plaque accumulation , tooth stability and integrity of multistr and wire and round wire bonded lingual retainers . METHODS Sixty-two subjects , who had completed treatment and who required fixed retention for the lower anterior segment , were assigned to either the  Round wire retainer group or the Multistr and wire retainer group . In the Round wire retainer group , a 0.036 inch round , stainless steel wire was bonded to the lingual surfaces of both lower canines . The Multistr and retainer group had a 0.015 inch multistr and wire bonded to the lingual surfaces of all lower anterior teeth . At least 12 months after debonding , the subjects were recalled and the following variables were recorded : Oral Hygiene Index ( OHI ) , Plaque Index ( PI ) of the lower anterior teeth , Gingival Index ( GI ) of the lower anterior teeth , Irregularity Index ( IRI ) of the lower anterior teeth , and the number of broken retainers . RESULTS There were no significant differences between the PI ( p = 0.165 ) and GI ( p = 0.150 ) of the two groups . More plaque was found on the distal surfaces of the lower anterior teeth in the group with multistr and wire retainers ( p = 0.02 ) . The lower anterior teeth were significantly more irregular in the group with round wire retainers compared to the group with multistr and wire retainers ( p = 0.002 ) . Although the multistr and wire retainers  fractured more frequently than the round wire retainers the difference was not statistically significant ( p = 0.325 ) . CONCLUSION More plaque accumulated on the distal surfaces of the lower anterior teeth in subjects with multistr and wire retainers than in subjects with round wire retainers . Multistr and wire retainers were better at maintaining incisor alignment than single span , round wire retainers The present study was performed to test whether bonded , orthodontic canine-to-canine retainers made of spiral wire tended to accumulate more plaque than retainers made of plain wire , and whether the presence of such retainers caused any damage to the teeth involved . 44 patients were classified in eight strata according to age , gender and gingival status . From each stratum , the patients were r and omly divided into 4 groups , each of which received either retainers made of thick plain wire bonded only to the canines , thick twisted wired bonded only to the canines , thin twisted wire bonded to each tooth or removable retainers .  Accumulation of plaque and calculus along the gingival margin and gingival inflammation were scored in lingual areas from canine to canine at time of fixed appliance removal and again 4 months after retainer insertion . In addition , accumulation of plaque and calculus and development of caries along the retainer wires were scored after 4 months . The results revealed no differences between the groups for any of the variables . No differences in accumulation of plaque was found between baseline and follow-up examinations . Gingival bleeding was scored less frequently after 4 months in retention than at time of debonding White spot or areas of decalcification are carious lesions of varying extent . The incidence and severity of white spots after a full term of orthodontic treatment were studied among patients in the separate private practice s of two of the authors . To establish a base line of comparison , the presence of white spots in a r and om sample of untreated persons was observed . The incidence of white spots among patients treated by a multibonded technique  was recorded at the time of debonding . In addition , white spots were sought in the before- and after-treatment Kodachrome slides of persons whose maxillary incisors had been h and ed . It was found that individual teeth , b and ed or bonded , exhibited significantly more white spot formation than was found in the control group . For the teeth studied , there was no difference in white spot formation in those that were b and ed or bonded . The labiogingival area of the maxillary lateral incisors had the highest incidence of white spots . When studied by segments , the highest incidence occurred among the maxillary incisors ; the lowest was in the maxillary posterior segment . No white spots were found on the lingual surfaces of m and ibular canines and incisors after prolonged use of a canine-to-canine bonded retainer . These findings suggest a relationship between resistance to white spot formation and the rate of salivary flow . Despite the lack of any preventive fluoride program among the study groups , 50 % of the patients demonstrated resistance to white spot formation . The obvious degree of latrogenic damage during orthodontic treatment suggests the need for preventive programs using fluoride . Further clinical research is needed 
    Output:
    
Regarding comfort , no clear differences were identified .
Conclusions There is not enough scientific evidence to support or not an association between FR design and gingival health , flossing frequency , or patient comfort .