In vitro Evaluation of Various Retention Protocols in Sustaining Treatment Outcomes Following Orthodontic Therapy.

Background: Orthodontic therapy aims at achieving stable treatment outcomes by ensuring retention of corrected tooth positions. Various retention protocols have been proposed, but their efficacy in sustaining treatment outcomes remains unclear. Materials and Methods: This in vitro study evaluated the effectiveness of different retention protocols in maintaining treatment outcomes following orthodontic therapy. Thirty extracted human premolars were subjected to simulated orthodontic movement and then divided into three groups: group A-Essix retainer, group B-Hawley retainer, and group C-bonded retainer. Retention efficacy was assessed through measurements of tooth movement over a period of 6 months using a digital caliper. Results: The mean amount of mesial movement observed in group A was 0.5 mm (SD ± 0.1), in group B was 0.7 mm (SD ± 0.2), and in group C was 0.3 mm (SD ± 0.1). Statistical analysis revealed significant differences in retention efficacy among the three groups (P < 0.05). Conclusion: The bonded retainer demonstrated superior efficacy in sustaining treatment outcomes by minimizing post-orthodontic tooth movement compared to Essix and Hawley retainers. Thus, the bonded retainer may be considered a preferable option for retention following orthodontic therapy.

Can vacuum-formed retainers maintain arch dimensions and alignment compared to Hawley and fixed bonded retainers after treatment with fixed appliances? A systematic review and meta-analysis.

BACKGROUND: Different types of retention appliances have been proposed over the years, but their effectiveness in maintaining arch dimensions and alignment after orthodontic treatment is still unclear. AIM: To assess the efficacy of vacuum-formed retainers (VFRs) in preserving arch widths, arch length, and anterior alignment in maxillary and mandibular arches, compared to removable Hawley retainers (HRs) or fixed bonded retainers (FBRs). Search methods: unrestricted literature search of five major databases up to March 2024. SELECTION CRITERIA: randomized/non-randomized clinical studies comparing VFRs to removable HRs or FBRs. DATA COLLECTION AND ANALYSIS: after duplicate study selection, data extraction, and risk of bias assessment, random effects meta-analyses of standardized mean differences and their 95% confidence intervals were performed, followed by meta-regressions, sensitivity analyses, and assessment of the quality of evidence with GRADE. RESULTS: Twenty-two prospective studies (4 non-randomized and 18 randomized controlled trials) involving 1797 patients (mean age 17.01 years, 38.3% males) were included. No significant differences were found in the intercanine width, intermolar width, and arch length between VFRs and HRs, in both arches (P > 0.05). However, VFRs were statistically more effective than HRs in terms of Little's irregularity scores (LII) in the maxilla (eight studies; SMD = -0.42; 95% CI: -1.03 to -0.09; P = 0.02; I2 = 73.4%) but not in the mandible (P = 0.12). No significant differences were reported for all considered outcomes between VFRs and FBRs in in both arches (P > 0.05), except for lower LII, where VFRs were significantly less efficient (eight studies; SMD = 1.49; 95% CI = 0.26-2.7; P = 0.02; I2 = 93%). Follow-up times, risk of bias, and wire type (of FBRs) did not show statistically significant effects on outcome variables. Sensitivity analyses showed robustness of the findings for including non-randomized and postretention studies. The certainty in these estimates was from moderate to low due to the risk of bias and inconsistency. CONCLUSIONS: Low to moderate quality evidence indicates that VFRs are as effective as HRs in maintaining arch widths, length, and alignment. Low-quality evidence found similar efficacy between VFRs and FBRs, with FBRs being statistically more effective at maintaining lower arch alignment, but the difference was not clinically significant. REGISTRATION: PROSPERO registration (CRD42024518433).

Three-dimensional analysis of posttreatment tooth movements despite bonded retainers: part II-lower jaw.

PURPOSE: Complications of bonded lingual retainers in terms of unexpected tooth movements have been reported with increasing frequency during the last decade, but the vast majority of the literature comprises case reports. The purpose of the present retrospective case-control study was to analyze the amount and direction of unwanted tooth movements despite lower bonded retainers, to analyze possible predisposing pretreatment- and treatment-related factors, and to seek for movement thresholds which could enhance the rapid and objective identification of critical cases. METHODS: Plaster casts of 1026 patients who completed orthodontic treatment and a subsequent retention phase of 2 years were screened for unintentional tooth movements. The study group comprised 39 patients with tooth movements in the lower jaw, while 39 randomly selected patients without visible tooth movements served as the control group. For all patients, plaster casts after debonding of multibracket appliances (T1) and after supervised retention (T2) were digitized, and a three-dimensional (3D) digital superimposition based on the best fit of premolars and molars was undertaken. Thereafter, translational as well as rotational movements were measured in all three planes of space. Pretreatment- and treatment-related factors of the study and control groups were compared. A severity classification based on rotational movement thresholds was applied to seek a critical amount of translational movements. RESULTS: The mean translational movements ranged between 0 and 0.4 mm and the average rotational movements between 0 and 1.6°. Large individual movements up to 1.9 mm translation and 16° rotation were seen. A twist-effect with opposite movements of the canines along the Y­axis could be confirmed. Compared to the control group, patients of the study group had a smaller intercanine distance at all timepoints. In addition, study group patients presented a slightly larger intercanine expansion during treatment and were more often affected by retainer bonding site detachments. Applying the severity classification based on rotational thresholds, translational movements of 0.5-1.0 mm along the X­ and Y­axis could serve as a critical threshold. It can be assumed that extrusive translational movements along the Z­axis seem to be of specific nature and perhaps do not reflect a retainer complication in terms of unwanted tooth movements. CONCLUSIONS: Patients with a larger intercanine distance after active treatment and those with more frequent retainer bonding site detachments could be at higher risk for unwanted tooth movements during fixed retention. Sagittal and transverse movements of 0.5-1.0 mm should sensitize the practitioner for further measures.

Three-dimensional analysis of posttreatment tooth movements despite bonded retainers: part I-upper jaw.

PURPOSE: Adverse side effects of fixed retainers in terms of unwanted tooth movements have been described for both the upper and lower jaw, but data about the extent and movement patterns for the maxilla are scarce. The purpose of the present retrospective case-control study was to analyze the amount and direction of unwanted tooth movements despite upper bonded retainers as well as to analyze possible predisposing pretreatment- and treatment-related factors. METHODS: Plaster casts of 1026 patients who completed orthodontic treatment and a subsequent retention phase of 2 years were screened for unintentional tooth movements. The study group comprised 57 patients with visually obvious tooth movements in the upper jaw, while 57 randomly selected patients without visible tooth movements served as control group. For all patients, plaster casts after debonding of multibracket appliance (T1) and after supervised retention (T2) were digitized, and superimposed digitally using a stable palatal reference area. Thereafter, translational and rotational movements were measured in all three planes of space. Pretreatment- and treatment-related factors of the study and control groups were compared by χ2 test, exact Fisher test, Mann-Whitney U test, and the T­test for independent samples. RESULTS: The mean translational movements ranged between 0 and 0.6 mm and the average rotational movements between 0 and 1.3°. Large individual movements up to 2.7 mm translation and 15.9° rotation were seen. A movement pattern around the Y­ and Z­axis with an opposite rotational peak at the canines ("upper twist effect") was identified. Compared to the control group, patients of the study group showed a significantly smaller intercanine width pretreatment. Also, study group patients presented a larger intercanine expansion and a slightly larger overjet reduction during treatment, and were more often affected by retainer bonding site detachments and wire fractures, but without reaching statistically significance. CONCLUSION: Upper bonded retainers show a similar unwanted movement pattern ("twist effect") like the one described for mandibular retainers.

Post-treatment stability, survival time and periodontal health associated with vacuum-formed, bonded and rapid prototype retainers: A prospective clinical study.

BACKGROUND: New technologies have paved the way for newer fabrication techniques, such as rapid prototyping, which has gained popularity in the fabrication of several orthodontic appliances including retainers. AIM: To evaluate the stability, survival time and periodontal health associated with vacuum-formed retainers (VFRs), bonded retainers (BRs) and rapid prototype retainers (RPRs) over a period of 12 months in retention. STUDY DESIGN: Prospective clinical study. METHODS: A total of 72 participants completing fixed orthodontic treatment were allocated to the following three groups by the investigators based upon their initial malocclusion, compliant and preferences: VFR; BR; and RPR. The primary outcome was Little's Irregularity Index (LII). Other stability parameters, including arch length (AL), inter-canine width (ICW) and inter-molar width (IMW), were also assessed immediately after debonding (T0) and 12 months (T2) after debonding. In addition, survival time, and calculus index and gingival index (GI) were assessed. RESULTS: LII showed a significant difference (P = 0.00) between the groups and was increased in the VFR group (0.18 ± 0.22 mm) compared to the BR (0.03 ± 0.05 mm) and RPR (0.01 ± 0.03 mm) groups but was not clinically significant. The mean survival time of maxillary retainers was longest for the RPR group (220.63 days; 95% confidence interval [CI] = 194.1-247.16) but there was no significant difference between the three groups (P = 0.43). The mean survival time of mandibular retainers was higher and the same for the VFR and RPR groups (240 days; 95% CI = 240-240) and there was no significant difference between the three groups (P = 0.38). The calculus index score (P = 0.00) was statistically significant between the groups, with an increased score for the BR group (0.33 ± 0.27) compared to the VFR (0.07 ± 0.16) and RPR (0.13 ± 0.22) groups. Similarly, the GI score (P = 0.02) was statistically significant between the groups and was increased in the BR group (0.01 ± 0.19) compared to the VFR (-0.15 ± 0.18) and RPR (-0.06 ± 0.15) groups. The increase in calculus index and GI scores for the BR group were not clinically significant. CONCLUSION: There were no clinically significant differences between the three retainer groups in terms of stability, periodontal health and time to failure.

Keeping the teeth in line: Exploring the necessity of bonded retainers in orthodontics: A narrative review.

In most recent studies, long-term retention after orthodontic treatment has been hypothesized that may be necessary to maintain the stability of the dentition and avoid post-treatment changes. The bonded fixed retainer is characterized by its clinical effectiveness, patient acceptance, and lack of patient complaints as compared with a removable retainer. An electronic database (such as PubMed, PubMed Central, Web of Science, Science Direct, Cochrane Library, Scopus, and ResearchGate) has been collected using specific keywords. Of the 152 articles, only randomized clinical trials that investigated different types of fixed retainers or compared fixed with removable retainers were illustrated in tables and included in this review. The present review has gone some way towards enhancing our understanding of the bonded fixed retainer, types, material, bonding methods, and how to improve its the success rate, besides the importance of new technology in fixed orthodontic retention.

Importance of Early Detection of Wire Syndrome: A Case Series Illustrating the Main Stages of the Clinical Gradient.

(1) Context and Objective: Wire syndrome (WS) refers to dental displacements which can be qualified as aberrant, unexpected, unexplained, or excessive of teeth still contained by an intact orthodontic retainer wire without detachment or fracture, leading to evolving aesthetic and/or functional consequences, both dental and periodontal. The clinical diagnosis of WS in severe cases is often easy. On the other hand, emerging cases must be detected early to stop this evolutionary process as soon as possible, as well as to effectively manage unwanted dental displacements and associated dento-periodontal tissue repercussions. The aim of this retrospective study was to understand the challenges and importance of early diagnosis, highlight the clinical gradient of WS, and clarify the key elements of diagnosis for many practitioners confronted with this type of problem. (2) Materials and Methods: Three cases of increasing complexity were described: the history of wire syndrome, a description of the key elements of its diagnosis, and the final diagnosis itself. (3) Results: Different types and locations of wire syndrome have been observed, from early form to terminal wire syndrome. The three main stages of the clinical gradient are described as follows. In the first case, wire syndrome starting on tooth 41, called the "X-effect" type, was suspected. X-effect wire syndrome on 21, X-effect wire syndrome on 41, and Twist-effect wire syndrome on 33 were diagnosed in the second case, which can be classified as an intermediate case. In the extreme clinical situation of the last case, severe and terminal wire syndrome on tooth 41, the X-effect type, was observed. (4) Conclusions: This case series presents the main stages of the clinical gradient of WS. Although in the case of early WS it is very difficult to identify and/or differentiate it from movements related to a classical relapse phenomenon, the diagnosis of terminal WS is very easy. The challenge for the practitioner is therefore to detect WS as early as possible to stop the iatrogenic process and propose a personalized treatment depending on the severity of clinical signs. The earlier WS is detected, the less invasive the treatment.

Comparison of six different CAD/CAM retainers vs. the stainless steel twistflex retainer: an in vitro investigation of survival rate and stability.

PURPOSE: To compare failure rates and maximum load capacity (Fmax) of six different computer-aided design/computer-aided manufacturing (CAD/CAM) retainers with those of the hand-bent five-stranded stainless steel twistflex retainer. MATERIALS AND METHODS: Six groups (n = 8 per group) of commercially available CAD/CAM retainers (cobalt-chromium [CoCr], titanium grade 5 [Ti5], nickel-titanium [NiTi], zirconia [ZrO2], polyetheretherketone [PEEK], and gold) and twistflex retainers were tested for long-term sufficiency and for Fmax using a self-developed in vitro model. All retainer models underwent a simulated ageing process of about 15 years (1,200,000 chewing cycles with a force magnitude of 65 N at 45° followed by storage in water at 37 °C for 30 days). If retainers did not debond or break during ageing, their Fmax was determined in a universal testing machine. Data were statistically analysed using Kruskal-Wallis and Mann-Whitney U­tests. RESULTS: Twistflex retainers did not fail (0/8) during ageing and had the highest Fmax (445 N ± 51 N). Ti5 retainers were the only CAD/CAM retainers that also did not fail (0/8) and had similar Fmax values (374 N ± 62 N). All other CAD/CAM retainers had higher failure rates during ageing and significantly lower Fmax values (p < 0.01; ZrO2: 1/8, 168 N ± 52 N; gold: 3/8, 130 N ± 52 N; NiTi: 5/8, 162 N ± 132 N; CoCr: 6/8, 122 N ± 100 N; PEEK: 8/8, 65 ± 0 N). Failure was due to breakage in the NiTi retainers and debonding in all other retainers. CONCLUSION: Twistflex retainers remain the gold standard regarding biomechanical properties and long-term sufficiency. Of the CAD/CAM retainers tested, Ti5 retainers seem to be the most suitable alternative. In contrast, all other CAD/CAM retainers investigated in this study showed high failure rates and had significantly lower Fmax values.

Simplifying placement of bonded retainers.

The placement of bonded retainers can be daunting to the inexperienced clinician. The aim of the present article was to share a simple means of using everyday intermaxillay elastics to effortlessly secure the wire, allowing the clinician to easily complete placement of the bonded retainer. The challenge of manipulating the wire, etch, bond and composite simultaneously is thus alleviated! A step-by-step explanation is provided.

Patient perceptions and attitudes regarding post-orthodontic treatment changes.

OBJECTIVES: To determine patient perceptions and attitudes regarding posttreatment changes at least 2 years after completion of orthodontic treatment. MATERIALS AND METHODS: A total of 125 patients (75 females, 50 males, aged 22.93 ± 2.98 years) were enrolled at least 2 years after debonding. Participants had either vacuum-formed retainers (VFRs) or bonded retainers (BRs). Posttreatment changes were evaluated digitally by comparing tooth positions at debonding and at least 2 years after debonding. A questionnaire was used to assess patient attitudes. Retainer usage, awareness of relapse, satisfaction with their current occlusion, and whether posttreatment changes were severe enough for them to consider retreatment were investigated. RESULTS: All patients showed some posttreatment changes in irregularity. Only 74% of patients wearing VFRs and 47.1% of patients wearing BRs were aware of posttreatment changes. Patients were more likely to notice posttreatment changes if there was an increase in mandibular irregularity of 1-3 mm. Awareness of posttreatment changes in the upper arch was higher in both groups. The majority of participants were satisfied with the results even if they noticed some minor posttreatment changes (VFR, 69.4%; BR, 76.5%). Dissatisfaction with posttreatment changes did not necessarily mean that a patient wanted retreatment. CONCLUSIONS: A total of 26% of patients wearing VFRs and 52.9% of patients wearing BRs were unaware of posttreatment changes. Approximately half of the patients who noticed posttreatment changes were still satisfied with the result 2 years after debonding. Even patients dissatisfied with the effect of posttreatment changes do not necessarily want retreatment.

Survival rates of mandibular fixed retainers: comparison of a tube-type retainer and conventional multistrand retainers : A prospective randomized clinical trial.

OBJECTIVE: The purposes of this study were to evaluate the survival rate of a tube-type mandibular fixed retainer and compare it to conventional multistrand retainers. MATERIALS AND METHODS: In all, 66 patients who had completed their orthodontic treatment were enrolled in this study. They were allocated randomly to a tube-type retainer group or a 0.020 multistrand fixed retainer group. In case of the tube-type retainer, a thermoactive 0.012 NiTi was placed into 6 mini-tubes passively bonded to the anterior teeth. The patients were recalled at 1, 3, 6, 12, and 24 months after retainer placement. During the 2­year follow-up period, any first-time failure of retainers was recorded. Kaplan-Meier survival analysis and log-rank tests were used to compare the failure rates between the two types of retainers. RESULTS: Of the 34 patients, 14 (41.2%) showed failure in the multistrand retainer group, whereas only 2 of 32 (6.3%) reported failure in the tube-type retainer group. There was a statistically significant difference in failure between the multistrand retainer and the tube-type retainer (log-rank test, P = 0.001). The hazard ratio was 11.937 (95% confidence interval 2.708-52.620; P = 0.005). CONCLUSION: The tube-type retainer can be used with fewer concerns about recurrent retainer detachments during orthodontic retention.

"Wire Syndrome" Following Bonded Orthodontic Retainers: A Systematic Review of the Literature.

(1) Background and objective: Tooth movements described as unexplained, aberrant, unexpected, unwanted, or undesirable can occur in the presence of an intact orthodontic retention wire, without detachment or fracture. This iatrogenic phenomenon, known little or not by many practitioners, responsible for significant dental and periodontal complications, both functional and aesthetic, is called "Wire Syndrome" (WS). It is therefore considered an undesirable event of bonded orthodontic retainers, which must be differentiated from an orthodontic relapse. The objective was to perform, for the first time, a systematic review of the literature in order to define the prevalence of WS and to study its associated clinical characteristics. (2) Methods: A systematic review of the literature was performed following the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and recommendations using an electronic search strategy on four databases complemented by a manual search. All the prospective and retrospective clinical studies, including case reports and series, written in English or French, clearly mentioning the description, detection, or management of WS were included. Three independent blinding review authors were involved in study selection, data extraction, and bias assessment using the Mixed Methods Appraisal Tool (MMAT). (3) Results: Of 1891 results, 20 articles published between 2007 and 2021 fulfilled the inclusion criteria, with a globally high risk of bias since 16 articles were case report/series. The analysis of each article allowed the highlighting of WS through 13 categories, as follows: prevalence, apparition delay, patient characteristics, arch and tooth involved, families of movements, dental and periodontal consequences, type of wire, risk factors, etiologies, treatment, and preventive approach. (4) Conclusion: This systematic review of the literature elaborated a synthesis on WS, allowing general practitioners, periodontists, and orthodontists to understand this adverse event, to facilitate the diagnostic approach, and to underline preventive measures against WS. This review was registered in the International Prospective Register of Systematic Reviews (PROSPERO; number CRD42021269297).

Conservative management of a cervical horizontal root fracture by long-term stabilisation: A case report.

Cervical root fractures are often more difficult to manage than fractures of the apical and middle third of the root, due to the weak chance of healing with dental hard tissue between fragments, and the likelihood of subsequent infection of the root canal system. This case report describes the management of a cervical horizontal root fracture by repositioning the coronal fragment of a maxillary central incisor, and long-term splinting using a bonded lingual orthodontic retainer wire. Throughout the 7-year stabilisation period with clinical and radiographic follow-up, the tooth has remained asymptomatic with radiographic evidence of progressive pulp canal obliteration. In applicable cases, long-term stabilisation of the fractured coronal fragment with a fixed orthodontic retainer may offer a minimally invasive solution to maintain pulp vitality, function and aesthetics until cessation of growth or until a more comprehensive, multidisciplinary approach is required.

Clinical comparisons of different fixed orthodontic retainers

ABSTRACT Objective: The aim of this prospective clinical study was to compare the clinical outcomes of three different fixed lingual retainers, in terms of effects on periodontal health and success rate. Methods: Forty five patients aged 13 to 25 years were randomly assigned into three groups, using bonded upper and lower lingual retainers. The study groups were as follows: Group 1- Bond-A-Braid®, Group 2- everStick® ORTHO, Group 3- Super-Splint. The follow-up appointments were performed two weeks (Baseline=T0), one month (T1), three months (T2), and six months (T3) after the application of retainers. Plaque Index (PI), Gingival Index (GI), Probing Depth (PD), Bleeding in Probing (BOP) and Retainer Failure were assessed at each appointment. Results: The everStick Ortho group showed significantly lower PI values on the upper-lower lingual side after three (p=0.008) and six (p=0.001) months. The everStick Ortho group had significantly lower upper lingual (GI) levels after six months, and lower lingual side levels after one month. The Super-Splint group showed significantly lower PD values on the upper lingual side after six months. The everStick Ortho group presented significantly lower BOP levels after six months on the upper lingual side. No significant differences between the groups (p>0.05) in terms of retainer failure were found. Conclusions: The everStick Ortho group presented better results in terms of periodontal health. The failure rates of the retainers were similar.

RESUMO Objetivo: O objetivo do presente estudo clínico prospectivo foi comparar a taxa de sucesso de três tipos de contenção lingual fixa e seus efeitos clínicos sobre a saúde periodontal. Métodos: Quarenta e cinco pacientes, com idades entre 13 e 25 anos, usando contenções fixas coladas nas arcadas superior e inferior foram agrupados, aleatoriamente, nos três seguintes grupos: Grupo 1 - Bond-A-Braid®; Grupo 2 - everStick® ORTHO; e Grupo 3 - Super-Splint. As consultas de acompanhamento foram feitas após duas semanas (inicial = T0), um mês (T1), três meses (T2) e seis meses (T3) da instalação das contenções. Em todas as consultas, foram avaliados o Índice de Placa (IP), Índice Gengival (IG), Profundidade de Sondagem (PS), Sangramento à sondagem (SAS) e Falha da Contenção. Resultados: O grupo everStick Ortho mostrou valores de IP significativamente menores nas faces linguais dos dentes superiores e inferiores após três (p=0,008) e seis (p=0,001) meses. O grupo everStick Ortho também apresentou níveis significativamente menores de IG na face lingual dos dentes superiores após seis meses, e face lingual dos dentes inferiores após um mês. O grupo Super-Splint mostrou valores significativamente menores de PS na face lingual dos dentes superiores após seis meses. O grupo everStick Ortho apresentou níveis significativamente menores de SAS na face lingual dos dentes superiores após seis meses. Quanto à falha na contenção, não houve diferença significativa (p>0,05) entre os grupos. Conclusões: O grupo everStick Ortho apresentou os melhores resultados em termos de saúde periodontal. As taxas de falha das contenções foram semelhantes.

Effect of Direct versus Indirect Bonding Technique on the Failure Rate of Mandibular Fixed Retainer-A Systematic Review and Meta-Analysis.

INTRODUCTION: Fixed retainer failure is a common cause of relapse and may require additional orthodontic treatment. The two main methods for bonding the mandibular fixed retainer include direct and indirect techniques. This topic has not been explored previously in a systematic review. Therefore, the objective of this systematic review was to evaluate the effect of direct versus indirect bonding technique on the failure rate of mandibular fixed retainer. METHODS: Online databases (PubMed, Dental and Oral Science, CINAHL, and Cochrane Central Register of Controlled Trials, Scopus) were systematically searched electronically for articles up until April 2021. Google Scholar and clinicaltrials.gov databases were utilized for hand searching. Randomized, non-randomized clinical trials and cohort studies on human subjects were considered regardless of language or year of publication. Orthodontic patients in their retention phase (mandibular 3×3 fixed retainer), in which the retainer was bonded using direct bonding technique as control and indirect as intervention were included. The outcome assessed was retainer failure rate. Two authors independently examined and extracted the data from the studies that satisfied the inclusion criteria. Risk of bias in clinical trials was assessed using the Cochrane Collaboration's tool, whereas risk of bias in cohort studies was assessed using the Newcastle-Ottawa Scale. The meta-analysis was conducted using the RevMan software V.5.3.5.22. The outcome was estimated using weighted average difference and 95% confidence intervals (CIs). The studies' heterogeneity was assessed using Cochrane's heterogeneity test (I2 Test). RESULTS: Four articles fulfilling the inclusion criteria were included in qualitative and quantitative synthesis. Retainer failure rates were analysed in a total number of 266 patients bonded with mandibular 3×3 retainers after orthodontic therapy. Direct bonding technique of fixed retainer on 131 patients was compared with indirect technique on 135 patients. There was no statistically significant difference in the rate of retainer failure between the two methods (95% CI, 0.67, 1.40). CONCLUSIONS: Within the limitations of insufficient evidence this systematic review and meta-analysis concluded that there is no difference in the failure rate of mandibular fixed retainers between direct and indirect bonding techniques. Due to the scarcity of available data, further studies are needed to establish definitively one's clinical benefit over the other.

A Survey of Retention Practices and Protocols Followed Among Orthodontists in India.

BACKGROUND: There are different types of retention protocols and retainers prescribed by the orthodontists across the globe. AIM: The study was conducted with the aim of evaluating the retention practices followed by the orthodontists in India. MATERIALS AND METHODS: A questionnaire link with a set of 29 questions was generated using the Google Forms App. The questions related to the basic demographic details followed by retention procedures in maxilla and mandible as related to the type of retainer, duration of wear, retention check-ups, and adjunctive procedures being followed. The Google forms were mailed to 1147 registered life members of the Indian Orthodontic Society. RESULTS: The overall response rate was 20.1%. On receiving of the completed questionnaires, the data were statistically analyzed. Dual mode of retention, fixed retainers with removable thermoplastic resin (TR)/vacuum formed retainers (VFR) (24%) were the common type of retention in maxilla whereas the fixed bonded retainer (44.5%) was more commonly used in mandible. Full time wear of maxillary retainer was recommended by 85.2% of the respondents. The recommended duration of the fixed retainer is for 2-5 years (41.9%). CONCLUSION: A trend towards more dual retention instead of solitary removable or solitary fixed retention, more VFR instead of Hawley-type retainers has been demonstrated in the survey.

Direct and indirect bonding of wire retainers to bovine enamel using three resin systems: shear bond strength comparisons / 대한치과교정학회지

OBJECTIVE: We compared the shear bond strength (SBS) of lingual retainers bonded to bovine enamel with three different resins using direct and indirect methods. METHODS: Both ends of pre-fabricated twisted ligature wires were bonded to bovine enamel surfaces using Light-Core, Tetric N-Flow, or Transbond XT. Phosphoric acid-etched enamel surfaces were primed with One-Step prior to bonding with Light-Core or Tetric N-Flow. Transbond XT primer was used prior to bonding with Transbond XT. After 24 hours in water at 37degrees C, we performed SBS tests on the samples. We also assigned adhesive remnant index (ARI) scores after debonding and predicted the clinical performance of materials and bonding techniques from Weibull analyses. RESULTS: Direct bonding produced significantly higher SBS values than indirect bonding for all materials. The SBS for Light-Core was significantly higher than that for Tetric N-Flow, and there was no significant difference between the direct bonding SBS of Transbond XT and that of Light-Core. Weibull analysis indicated Light-Core performed better than other indirectly bonded resins. CONCLUSIONS: When the SBS of a wire retainer is of primary concern, direct bonding methods are superior to indirect bonding methods. Light-Core may perform better than Transbond XT or Tetric N-Flow when bonded indirectly.

Effect of thermocycling on shear bond strength and mode of failure of bonded retainer using flowable composite resin / 대한치과교정학회지

The purpose of this study was to evaluate the effects of thermocycling on shear bond strength and mode of failure of orthodontic bonded retainer using flowable composite resin and to ascertain whether the flowable composite resin is useful for use as adhesive for orthodontic bonded retainers. One hundred and sixty freshly extracted human premolars were collected and eighty bonded retainer specimens were fabricated. They were randomly separated into 2 groups (Group G: general composite resin-CharmFil(R), Group F: flowable composite resin-CharmFil Flow(R), wire: Tri-flex(R)). Each group was divided into 2 subgroups (Subgroup 24: stored in water at 37 degrees C for 24 hours for baseline data, Subgroup T: stored in water at 37 degrees C for 24 hours and thermocycled between 5 +/- 2 degrees C and 55 +/- 2 degrees C for 500 cycles before testing the in vitro shear bond strength). Shear bond strength was measured and mode of failure was evaluated with a stereomicroscope. There was no statistical difference in shear bond strength and mode of failure between the bonded retainer using general composite resin and flowable composite resin. Therefore, in considering shear bond strength and mode of failure, it is sufficient to use flowable composite resin as resin adhesives for bonded retainers.

A study of shear bond strength of bonded retainer according to the bonding method and type of wires / 대한치과교정학회지

The bonded orthodontic retainer constructed from composite and multistrand orthodontic wire provides an esthetic and efficient system for maintained retention. This study was designed to measure shear bond strength of bonded retainers and to suggest a optimal combination of a multistrand wire and bonding method used when bonded retainer was fabricated. 160 sound maxillary and mandibular premolars were used for 80 test samples. After Uniformizing bonding area, length of wire, and thickness of composite, multistrand wire was bonded to fabricated a bonded retainer by direct or indirect bonding method. Shear bond strength and extension length of each sample were measured by a universal testing machine. The results of this study were as follows: 1. In vitro shear bond testing found 6-stranded, 0.0155 inch wires to have the largest shear bond strength and 3-stranded, 0.0195 inch wires to have the least shear bond strength. But, These difference was not statistically significant(p<0.05). 2. In vitro extension testing found 3-stranded, 0.0155 inch wires to have the largest extension length and 3-stranded, 0.0195 inch wires to have the least extension length(p<0.05). The larger diameter wire was used, the larger extension length was shown. But, the strand of wire is not related to the extension length of wire. 3. In comparison with direct bonding method, larger shear bond strength and extension length was shown in indirect bonding method(p<0.05).