Article

Long-term stability after orthodontic treatment: Nonextraction with prolonged retention

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Abstract

A sample of 22 previously treated orthodontic cases was studied to evaluate long-term stability. All cases were treated nonextraction with fixed edgewise appliances and were without retainers a minimum of 5 years. Data were obtained from study models, although 14 of the 22 cases had longitudinal cephalometric radiographs. The average retention time with a mandibular fixed lingual retainer was 8.4 years. The irregularity index pretreatment was 8.0 mm in the maxillary arch and 5.2 mm in the mandibular arch; at the end of treatment it was 0.9 mm and 1.0 mm, respectively, and at the postretention stage it was 2.0 mm and 2.4 mm, respectively. Resolution of the lower irregularity index was accomplished without incisor advancement or distal movement of the mandibular molar, however, both arches were expanded transversely. During the posttreatment stage all variables showed relapse except for the expanded maxillary canines and premolars. However, the mandibular anterior segment demonstrated relatively good alignment at the long-term stage, which may be a reflection of prolonged mandibular retention.

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... There is a lack in the orthodontic literature regarding what type of treatment has greater long-term stability and also what are the changes in the dental arches when comparing extraction and nonextraction treatments in the long-term. Most of the follow-up studies focused on morphologic changes in the mandibular arch evaluating only patients treated nonextraction 8,[16][17][18] or with premolar extraction. 7,[19][20][21][22] In addition, few studies focus mainly on changes in the maxillary arch, 23,24 and studies that focus on changes in both the maxillary and mandibular arches have a mean postretention follow-up time of 20 years. ...
... These results were similar to previous studies. 8,24 However, Sadowsky et al 17 reported smaller values of irregularity index at T3. This difference could be related to the prolonged retention time in their study and a long-term follow-up observation period in our study. ...
... This finding is in agreement with a previous study, 45 although different results have been reported. 16,17 Sadowsky et al, 17 found that the maxillary and mandibular arches were notably expanded, although the maxillary more than the mandibular arch; however, the mandibular arch presented greater crowding at pretreatment than the present investigation. This remarkable expansion could be to resolve crowding, which caused an increase in the arch perimeter. ...
Article
Introduction The objective of this research was to evaluate the anterior tooth alignment and dental arch dimension changes after orthodontic treatments with and without premolar extractions in the long-term. Methods Fifty-seven patients with Class I and Class II malocclusion were divided into 2 groups. Group 1 included 16 patients treated with nonextraction therapy, with mean initial (T1), final (T2), and long-term follow-up (T3) ages of 13.20 years, 15.07 years, and 50.32 years, respectively. The mean treatment (T2 − T1) and long-term follow-up (T3 − T2) times were 1.86 years and 35.25 years, respectively. Group 2 included 41 patients treated with extraction of 4 first premolars, with T1, T2, and T3 ages of 13.31 years, 15.63 years, and 53.60 years, respectively. The mean treatment and long-term follow-up times were 2.32 years and 37.96 years, respectively. The mean retention time was 2.26 years for both groups. The dental casts were obtained and digitized at T1, T2, and T3 stages. The following measurements were obtained: Little irregularity index, arch length, perimeter, and intercanine, interpremolar, and intermolar widths. Intragroup and intergroup comparisons were performed with repeated measures analysis of variance and t tests, respectively. Results Anterior tooth irregularity index increased at T3 in both groups. In addition, all arch dimensions, except the intercanine width, were significantly smaller in the extraction group at T3. Both groups showed similar arch dimension changes at T3, except for the mandibular arch perimeter. The percentage of mandibular anterior tooth alignment change was significantly greater in the nonextraction than in the extraction group. Conclusions There was no difference in the changes of anterior alignment and transverse arch dimensions in patients treated with and without premolar extraction at T3, but the percentage of mandibular anterior tooth alignment changes was higher in the nonextraction than in the extraction patients at T3. The mandibular arch perimeter showed more of a decrease at T3 in extraction patients.
... Con relación al tiempo necesario de uso de las contenciones, se sugiere su uso a largo plazo o de manera indefinida, sin embargo, no está claro cuánto tiempo debiesen estar presentes en boca para reducir el riesgo de apiñamiento en la zona anterior después del tratamiento de ortodoncia (17) . Se ha demostrado que un período de contención de más de ocho años con contenciones fijas da como resultado un mejor mantenimiento de la alineación de los incisivos inferiores que otros estudios que informaron tiempos de retención más cortos (17) . ...
... Con relación al tiempo necesario de uso de las contenciones, se sugiere su uso a largo plazo o de manera indefinida, sin embargo, no está claro cuánto tiempo debiesen estar presentes en boca para reducir el riesgo de apiñamiento en la zona anterior después del tratamiento de ortodoncia (17) . Se ha demostrado que un período de contención de más de ocho años con contenciones fijas da como resultado un mejor mantenimiento de la alineación de los incisivos inferiores que otros estudios que informaron tiempos de retención más cortos (17) . Un factor importante para considerar al planificar la contención son las expectativas del paciente sobre la estabilidad de la alineación de sus incisivos inferiores (18) . ...
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Resumen Las contenciones fijas en ortodoncia han demostrado tener excelentes resultados para la estabilidad y durabilidad del tratamiento. A pesar de esto, se ha observado que existen ciertos movimientos dentarios indeseados totalmente diferentes a una recidiva a su posición inicial previa al tratamiento de ortodoncia. El llamado “efecto giro” es uno de ellos, y se caracteriza por ser una inclinación en sentidos opuestos de los caninos contralaterales, en donde uno presenta una inclinación hacia vestibular y el otro hacia lingual o palatino. Se presenta principalmente en la mandíbula, a pesar de que la contención permanece perfectamente adherida a los dientes. El objetivo de esta revisión bibliográfica es evaluar los distintos factores reportados en la literatura que puedan estar relacionados con la aparición del “efecto giro” y qué tan relevantes pueden ser en su desarrollo. Como conclusión es importante considerar el carácter multifactorial de este tipo de complicaciones, en donde el tipo y calidad del alambre que se utilice para la contención, junto con las características periodontales del paciente demostraron tener cierta participación en la génesis de este, por lo tanto, resulta fundamental concientizar a los pacientes de la importancia de los controles ortodóncicos periódicos posteriores al retiro de los aparatos fijos para monitorear y controlar los resultados oclusales logrados y el estado de los dispositivos de contención instalados.
... Existen varios diseños de contenciones fijas, siendo los más utilizados los alambres de multi-hebras adheridos de canino a canino o un alambre redondo de acero inoxidable arenado adherido solo a los caninos (13) . Con relación al tiempo necesario de uso de las contenciones, se sugiere su uso a largo plazo o de manera indefinida, sin embargo, no está claro cuánto tiempo debiesen estar presentes en boca para reducir el riesgo de apiñamiento en la zona anterior después del tratamiento de ortodoncia (17) . Se ha demostrado que un período de contención de más de ocho años con contenciones fijas da como resultado un mejor mantenimiento de la alineación de los incisivos inferiores que otros estudios que informaron tiempos de retención más cortos (17) . ...
... Con relación al tiempo necesario de uso de las contenciones, se sugiere su uso a largo plazo o de manera indefinida, sin embargo, no está claro cuánto tiempo debiesen estar presentes en boca para reducir el riesgo de apiñamiento en la zona anterior después del tratamiento de ortodoncia (17) . Se ha demostrado que un período de contención de más de ocho años con contenciones fijas da como resultado un mejor mantenimiento de la alineación de los incisivos inferiores que otros estudios que informaron tiempos de retención más cortos (17) . Un factor importante para considerar al planificar la contención son las expectativas del paciente sobre la estabilidad de la alineación de sus incisivos inferiores (18) . ...
Article
Las contenciones fijas en ortodoncia han demostrado tener excelentes resultados para la estabilidad y durabilidad del tratamiento. A pesar de esto, se ha observado que existen ciertos movimientos dentarios indeseados totalmente diferentes a una recidiva a su posición inicial previa al tratamiento de ortodoncia. El llamado “efecto giro” es uno de ellos, y se caracteriza por ser una inclinación en sentidos opuestos de los caninos contralaterales, en donde uno presenta una inclinación hacia vestibular y el otro hacia lingual o palatino. Se presenta principalmente en la mandíbula, a pesar de que la contención permanece perfectamente adherida a los dientes. El objetivo de esta revisión bibliográfica es evaluar los distintos factores reportados en la literatura que puedan estar relacionados con la aparición del “efecto giro” y qué tan relevantes pueden ser en su desarrollo. Como conclusión es importante considerar el carácter multifactorial de este tipo de complicaciones, en donde el tipo y calidad del alambre que se utilice para la contención, junto con las características periodontales del paciente demostraron tener cierta participación en la génesis de este, por lo tanto, resulta fundamental concientizar a los pacientes de la importancia de los controles ortodóncicos periódicos posteriores al retiro de los aparatos fijos para monitorear y controlar los resultados oclusales logrados y el estado de los dispositivos de contención instalados.
... The mandibular anterior irregularity shows fast and continuous increases, even exceeding the initial scores [1]. Anterior crowding relapse after orthodontic treatment is a typical orthodontic patient's chief complaint in private practice [6][7][8]. The etiology of relapse is multifactorial and still is not entirely understood. ...
... The aging of the occlusion is a physiological phenomenon that promotes continuing dentoalveolar changes throughout adult life [11]. No specific characteristics, variables or kinds of treatment could be used to predict long-term results after orthodontic treatment [6][7][8]. ...
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Background Occlusal stability is one of the goals of orthodontic treatment, and keeping teeth aligned in the long term is a challenge for the orthodontist. This study aimed to compare the long-term incisors irregularity and dental arches dimensions changes in subjects treated with 4 premolar extractions with different pretreatment Little's irregularity index (LII). The knowledge of long-term outcomes is evidence-based information for the prognosis of future treatments. Methods In total, 41 treated subjects were divided into two groups according to mandibular Little irregularity value at pretreatment (mild or severe). The maxillary and mandibular LII, transversal, and longitudinal widths were assessed at pretreatment, posttreatment, and 37-year posttreatment. Chi-square and independent t tests were used for intergroup comparison. Results The groups presented similar behavior for all stages of maxillary and mandibular arch dimensions changes. Maxillary irregularity was corrected in both groups after treatment, and the alignment was acceptable in the long term. In the mild group, the mandibular incisor irregularity returned to pretreatment values in the long term. The mandibular LII increased in the severe group but did not return to pretreatment values in the long term. Conclusions The mild crowding group presented proportionally more relapse of mandibular incisor irregularity than the severe crowding group in the long term. Even so, the correction of mild and severe crowding with the extraction of 4 premolars showed satisfactory results in the long term, even with the presence of maturational changes and relapse.
... As such, the level of post-treatment change is in keeping with other studies and likely reflects suboptimal adherence with removable retainer wear. Sadowsky et al. demonstrated an increase in LII of 1.1 mm in participants from post-treatment to postretention [14]. The increased relapse in irregularity experienced may be explained by the retrospective nature, the small sample size and the longer follow-up period (> 5 years) [14]. ...
... Sadowsky et al. demonstrated an increase in LII of 1.1 mm in participants from post-treatment to postretention [14]. The increased relapse in irregularity experienced may be explained by the retrospective nature, the small sample size and the longer follow-up period (> 5 years) [14]. Whilst this study involved a shorter-term evaluation, a meaningful assessment of stability can be achieved at 12 months as a high proportion of relapse is known to occur soon after treatment ceases with the rate of change reducing over time [15]. ...
Article
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Abstract Background It is thought that achieving a normal overjet may help to stabilise the alignment of the maxillary anterior dentition. Little’s Irregularity Index is limited in assessing discrete post-orthodontic changes, fails to account for reciprocal rotations and is not sensitive to dental changes in three planes. A more holistic tool for the assessment of post-treatment change is therefore required. Aim To compare the post-treatment stability of maxillary anterior dental alignment in subjects treated either to a Class I incisor relationship or an increased overjet (> 4 mm) following fixed appliance-based orthodontics using a novel measurement tool. Materials and methods The Orthodontic Alignment Index (OAI) was developed and validated using a panel of 63 raters. The new index accounts for a range of weighted features including contact point displacement, spacing, reciprocal rotations, inclination, angulation and vertical discrepancy. A retrospective cohort study was undertaken at the Institute of Dentistry, Queen Mary University of London. Recruitment took place over a 4-year period. All participants had removable retainers in the maxillary arch only. The stability of maxillary anterior teeth was assessed using Little’s Irregularity Index (LII) and the OAI. Subjects were recruited at least 12 months following completion of dual-arch fixed appliance-based treatment. Results Eighty-two participants were included with a positive correlation observed between LII and OAI at the 12-month post-treatment review with a 1-mm increase in LII associated with a 2-point increase in the OAI (P
... On the other side, quite a high percentage of clinicians chose different retention periods: "at least as active treatment", "at least two times longer as active treatment", or "at least a half of the active treatment". According to scientific evidence on the stability of orthodontic alignment, ceasing retention at any time does not guarantee stable orthodontic alignment [32]. Any malalignment of the anterior teeth may be esthetically unacceptable for the patient. ...
... The diversity of wires used for fixed retention reflects a lack of clinical scientific evidence proving a lower failure rate of any wire [18,32]. Most of the survey studies drew attention to the lack of clear clinical guidelines and sought the guidelines on which type of retention should be applied [9,11,14]. ...
Article
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The aim of the study was to analyze retention protocols and materials for fixed retainers used by clinicians providing orthodontic treatment in Poland. The survey was carried out from February to April 2021. The questionnaire was designed using the Google Forms tool. After validation, the questionnaire was delivered to verified active orthodontists gathered in a closed social media group of 615 members. Finally, 104 answers were received. Answers to individual questions were provided in percentages and tabularized. A chi-squared test of proportion was used to compare: the proportion of clinicians using retainers of different characteristics and the proportions of clinicians indicating the superiority of a given clinical solution. Rectangular steel braided wire was rated as most reliable. However, doctors who declared to use gold chain were mostly solely using this type of wire. Multistranded round wire was rated the worst. Fiber-reinforced composite was mainly used in periodontal patients. The protocols used by Polish orthodontic practitioners relied on double long-term retention with regular follow-up. The most popular material was stainless steel braided rectangular wire bonded with a flowable composite. Most clinicians believed they could maintain the treatment results, but they declared that patients’ cooperation was a challenge.
... A literatura ortodôntica é escassa em relação a qual tipo de tratamento tem maior estabilidade em longo prazo e também sobre quais alterações ocorrem na forma do arco dental quando comparamos tratamentos ortodônticos realizados com e sem extrações dentárias, principalmente muitos anos após o tratamento. A maioria dos estudos em longo prazo foca-se apenas em características individuais, como as alterações morfológicas na mandíbula em pacientes tratados sem extrações (GLENN; SINCLAIR; ALEXANDER, 1987;SADOWSKY et al., 1994;WEINBERG;SADOWSKY, 1996;FREITAS et al., 2004;FREITAS et al., 2007) e pacientes tratados com extrações de pré-molares (WALLEN; RIEDEL;ARTUN, 1988;FREITAS, et al., 2006;DYER;VADEN;HARRIS, 2012). Também existem estudos que avaliaram as alterações oclusais somente na maxila (CANUTO et al., 2013a;CANUTO et al., 2013b;GUIRRO et al., 2016). ...
... A recidiva do apinhamento anterior é um fenômeno imprevisível que acontece inevitavelmente na maioria dos casos tratados (UHDE;SADOWSKY;BEGOLE, 1983;SHAH, 2003). Estudos mostram que ocorre com mais frequência na mandíbula do que na maxila (KAHL-NIEKE;FISCHBACH;SCHWARZE, 1995). ...
Chapter
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Occlusion management in Implant Dentistry
... Achieving long-term stability of the orthodontic treatment is a significant challenge for a number of reasons. 1,2 The problem may be in the definition of long-term stability itself. If we are aiming to achieve an occlusal result that is permanent and unchangeable forever, then both clinicians and patients are likely to be disappointed. ...
... Many studies have shown that long-term stability is problematic when retention is discontinued, with some degree of relapse inevitable. 1,2,9 Previous researchers have tried to define acceptable levels of relapse after retention has been stopped. Little et al. 10 and Alexander et al. 11 have suggested that irregularity of <3.5 mm in the labial segment may be considered an acceptable level of relapse; however, some patients would not tolerate this amount of irregularity. ...
Article
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Long-term stability of orthodontic treatment results is problematic. Long-term or even lifelong retention with bonded retainers is being increasingly used among clinicians. Bonded retainers can provide an efficient and attractive method of retention, particularly because they require minimal compliance from patients. However, the use of bonded retainers is associated with relatively frequent complications, such as detachments of the adhesive layer or wire fractures, as well as unexpected complications with potentially severe consequences with associated periodontal and general health risks. It is imperative that the whole dental team are aware of these pitfalls and complications, and appreciate how to minimise and address these. Encourages balanced discussion among the dental team concerning long-term retention with bonded retainers, focusing on the possible complications associated with the use of bonded retainers.Discusses the factors influencing occurrence of complications and the potential negative effects on adjacent tissues as well as general health.Stresses the importance of monitoring bonded retainers by all members of the dental team and early interception of complications in order to prevent development of severe clinical consequences. Encourages balanced discussion among the dental team concerning long-term retention with bonded retainers, focusing on the possible complications associated with the use of bonded retainers. Discusses the factors influencing occurrence of complications and the potential negative effects on adjacent tissues as well as general health. Stresses the importance of monitoring bonded retainers by all members of the dental team and early interception of complications in order to prevent development of severe clinical consequences.
... Because the palatal button was removed after distalization, there was less transverse control of the premolars, which may have buccally moved during retraction, which corroborates other studies. 14,22,38,[40][41][42][43][44] After that, these distances remained stable in the longterm posttreatment stage. ...
... 38,47,48 These transverse changes corroborate with other studies (Table II; Fig 3). 14,24,38,40,42,44,45,49 Overall, treatment with the pendulum, followed by with fixed appliances, does not change the maxillary intercanine distance and causes significant and permanent increases in only the first and second premolar transverse distances. Interfirst and intersecond molar transverse distances increase immediately after the distalization phase but return to similar original dimensions at the end of treatment. ...
Article
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Introduction This study aimed to evaluate the stability of transverse changes after Class II malocclusion correction with the pendulum fixed distalizer, followed by preadjusted edgewise fixed orthodontic appliances. Methods This longitudinal study was conducted in the maxillary dental casts of 20 Class II malocclusion subjects (mean age, 12.5 years; 14 females and 6 males). Eighty 3-dimensional maxillary dental casts were analyzed; 20 at the beginning of treatment, 20 after distalization, 20 after edgewise appliance debonding, and 20 at 5 years posttreatment. Maxillary transverse distances between canines, first premolars, second premolars, first molars, and second molars were analyzed using Geomagic Studio 5 (3D Systems, Rock Hill, SC). Results There were no significant changes in intercanine distance during and after treatment. There were significant interfirst and intersecond premolar distance increases during treatment. There were significant interfirst and intersecond molar distance increases during the distalization phase. However, there were significant decreases in these distances at the end of treatment. There were no significant long-term posttreatment changes. Conclusions The intercanine distance remains stable during and after treatment. The interfirst and intersecond premolar distances significantly increase during treatment and remain stable after treatment. The interfirst and intersecond molar distances increase during the distalization phase, decrease at the end of treatment, and remain stable after treatment.
... Relapse is a physiological response of the supporting tissues to force application and has been a major challenging clinical issue with respect to the goals of successful orthodontic treatment. 1,2 The classic approaches to orthodontic retention primarily involve the use of fixed or removable retainers whose caveats include the reliance on patient compliance and the long duration of retention required to ensure stability. 3 Various systemically and locally administrated agents have been reported to reduce the amount of relapse in animal models, including bisphosphonate, 4 osteoprotegerin, 5 relaxin, 6 and bone morphogenetic proteins., 7 Although the mechanisms of action are different, relapse is decreased by modification of the remodeling process of the dental supporting tissues. ...
... A hypolipidemic agent, simvastatin, has recently been expected to serve as a therapeutic agent for osteoporosis. These drugs, known as statins, represent a new approach for treating osteoporosis, one which emphasizes building new bone to replace bone that has already 1 9 identified statins as the only natural product that specifically increased bone morphogenetic protein-2 (BMP-2) gene expression in osteoblasts and increased levels of bone formation proteins in these cells. There was also a striking increase in osteoblast cell numbers after statin application since BMP-2 is one of the most potent growth factors targeting bone formation in vivo, which stimulates osteoblastic differentiation and proliferation. ...
... Immunohistochemical findings showed that LLLT increased Col-I expression and facilitated Metalloproteinases (MMP) gene expression [41]. More specifically, it has been shown that, during the OTM, LLLT stimulated collagen degradation via MMP activation, maintaining balance with collagen synthesis [41,42]. By means of the accelerated collagen repair, the moved teeth establish a new position within the alveolar bone with freshly produced periodontal ligament (PDL) fibers [42]. ...
... More specifically, it has been shown that, during the OTM, LLLT stimulated collagen degradation via MMP activation, maintaining balance with collagen synthesis [41,42]. By means of the accelerated collagen repair, the moved teeth establish a new position within the alveolar bone with freshly produced periodontal ligament (PDL) fibers [42]. ...
Article
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The present study evaluated the effects of low-level laser therapy (LLLT) by means of a diode laser in accelerating orthodontic tooth movement (OTM). After extraction of the first upper premolars for orthodontic purpose, 82 maxillary canines which needed distalization were analyzed in 41 enrolled patients (21 males, 20 females, mean age 13.4 ± 2.1 years). On all experimental sites, an orthodontic force of 50/N was applied by a nickel-titanium (NiTi) closed coil spring (G&H, Franklin, IN, USA) in order to obtain the space closure. Using a split mouth randomized design, the test side was treated using a diode laser (Wiser Laser Doctor Smile, Brendola, Italy) operating at 810 nm wavelength in continuous wave mode at both the buccal and palatal side on three points/side (distal, medial and mesial) (1 W output power, continuous wave of 66.7 J/cm2, energy density of 8 J) at baseline and at 3, 7, and 14 days and every 15 days until the space closed. On the control side, the opposite selected canine was treated only using orthodontic traction. The primary outcome chosen was the overall time needed to complete the levelling and closing space, measured on a study cast. The secondary outcome chosen was the evaluation of pain levels related to tooth traction, using a Visual Analogue Scale (VAS), recorded at 3, 7, and 14 days after treatments. The mean space closures of the maxillary canines were comparable between groups [Test, 4.56 mm (95% CI 3.9–4.8); Control, 4.49 mm (95% CI 3.8–4.7), p = 0.456]. The laser group yielded less mean time [84.35 ± 12.34 days (95% CI 79.3–86)] to accomplish space closure compared to the control group [97.49 ± 11.44 days (91.7–102.3)] (p < 0.001). The test side showed a significant reduction in the average range of dental pain at 3 [Test, 5.41 (95% CI 5.1–5.6); Control, 7.23 (95% CI 6.9–7.6), p < 0.001], 7 [Test, 4.12 (95% CI 3.8–4.7); Control, 5.79 (95% CI 5.4–5.8), p < 0.001], and at 14 days [Test, 2.31 (95% CI 1.8–2.3); Control, 3.84 (95% CI 3.3–4.2), p < 0.001] after treatment (p < 0.001). This study demonstrates that the use of LLLT therapy was effective in accelerating tooth movement and reducing pain levels related to OTM.
... It is well known that certain features of malocclusion have a high relapse potential including severe pre-treatment contact point displacement, spaced dentition, rotated teeth [4,5], and periodontally compromised teeth with bone loss [6,7]. Moreover, some orthodontic tooth movements may be inherently unstable and more prone to relapse such as changes in the antero-posterior lower incisor position [8], expansion of lower inter-canine width [9,10], and closure of anterior open bites [11]. Fixed Orthodontic bonded retainers (FOBRs) are commonly used in cases which have a higher potential of relapse. ...
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Objectives To systematically assess the scientific literature for the prevalence of failure rate of fixed orthodontic bonded retainer (FOBR). Method Randomized clinical trials (RCTs) and prospective non-RCTs involving participants who had FOBR fitted were included. The Cochrane Central Register of Controlled Trials, Web of science, MEDLINE, and EMBASE via OVID were searched from inception to January 2023. Risk of bias was assessed using the Cochrane RoB 2 and Newcastle–Ottawa tools. The main outcome was the failure rate of FOBRs. The secondary outcome was to identify factors that can influence the failure of FOBR. Meta-analyses and sensitivity analyses were undertaken using Revman, version5.4. A random-effects model was used. Quality assessment using Grading of Recommendations Assessment, Development, and Evaluation. Results Thirty-four studies (25 RCTs and 9 prospective clinical studies) (3484 participants) were included in this review. The overall failure rate of bonded retainers, after excluding high-risk studies, was 35.22% (95% confidence interval [CI] 27.46–42.98). The failure rate is increased with the duration of follow up; with short-term follow-up rate 24.18% (95% CI 20.16–28.21), medium-term follow up 40.09% (95% CI 30.92–49.26), and long-term follow up 53.85% (95% CI 40.31–67.39). There is a low level of evidence to suggest there is no statistically significant difference in the failure rate of fixed retainers using direct versus indirect bonding methods, using liquid resin versus without liquid resin, and fibre-reinforced composite retainers compared to multi-stranded stainless steel retainers. Discussion There is low-quality evidence to suggest that the failure rate of FOBR is relatively high. There is a need for high-quality, well-reported clinical studies to assess factors that can influence the failure rate of FOBR. Registration CRD42021190910.
... They suggest that orthodontist should be aware that long-term changes in dental relationships can occur many years after treatment and take this into account when planning retention and when advising patients as to the potential benefits of orthodontic treatment. The long-term stability of non-extraction treatment with prolonged retention was studied by Sadowsky et al. 15 The patients in their study were at least 5 years out of retention. All patients had been retained with a fixed lower retainer. ...
... • Long term removable or fixed retainer to avoid lower incsior crowding (Sadowsky et al., 1994), ...
... • Long term removable or fixed retainer to avoid lower incsior crowding (Sadowsky et al., 1994), ...
... Based on the perception that postretention crowding of mandibular incisors is the first sign of treatment instability and the precursor of maxillary crowding and relapse of an overbite, the mandibular labial segment has been the focus of research on orthodontic treatment stability. [1][2][3][4][5][6][7][8] Factors evaluated in numerous studies throughout the years as potential factors related to stability are a violation of anterior and transversal limits of dentition, 9,10 treatment timing, 7,11 duration and type of retention, 5,12 posttreatment growth or maturational changes, 13,14 severity malocclusion, 13 occlusal factors, and treatment approach. 4,15 In most of these studies, extraction and nonextraction treatments were compared. ...
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Introduction: This study aimed to compare long-term mandibular incisor stability in nongrowing patients with moderate crowding treated nonextraction with and without interproximal enamel reduction (IPR). Methods: Forty-two nongrowing patients with Class I dental and skeletal malocclusion with moderate crowding were divided into 2 groups with an equal number of patients depending on whether IPR was used (IPR group) or not (non-IPR group) during treatment. All patients were treated by the same practitioner and used thermoplastic retainers full-time for 12 ± 1 months at the end of the active treatment. Changes in Peer Assessment Rating scores, Little's irregularity index (LII), intercanine width (ICW), and mandibular incisor inclination (IMPA and L1-NB°) were evaluated using pretreatment, posttreatment, and 8 ± 1 years postretention dental models and lateral cephalograms. Results: At the end of the treatment, Peer Assessment Rating scores and LII decreased, and ICW, IMPA, and L1-NB° increased significantly (P <0.001) in both groups. At the end of the postretention period, in both groups, LII increased, and ICW decreased significantly (P <0.001) compared with posttreatment values, whereas IMPA and L1-NB remained stable. When treatment changes were compared, increases in ICW, IMPA, and L1-NB were significantly (P <0.001) higher in the non-IPR group. When postretention changes were compared, the only significant difference between 2 groups was observed in ICW. The decrease in ICW was significantly higher in the non-IPR group. Conclusions: Long-term stability of mandibular incisor alignment in Class I nongrowing patients with moderate crowding treated nonextraction with and without IPR was similar.
... Additionally, a small group of patients may be dissatisfied with the results of their initial treatment [6]. While it is recommended that orthodontic patients wear their retainers permanently to achieve lifelong stable results [7], it has been reported that some patients are not well informed about the type and duration of orthodontic retention [8]. ...
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This retrospective real-world study aimed to evaluate the outcomes of clear aligner treatment (CAT) and patient demographics of patients seeking orthodontic re-treatment who had previously received orthodontic treatment in childhood or adolescence. The study was conducted using anonymized data from DrSmile (Berlin, Germany), a CAT provider in Europe. Data were collected from a total of 2080 patients in Germany (71.5% female, 28.5% male, ranging from 18-70 years, median 29.0 years), who completed their CAT between 1 June and 30 June 2022. Patients were divided into two groups: adult first-treatment patients (n = 1587) and adult re-treatment patients (n = 493). Results showed that re-treatment patients had a shorter treatment duration (p < 0.05), required fewer interproximal reductions (IPR) (p < 0.001), and had fewer clinical visits (mean 2.96 versus 4.14 visits) than first-treatment patients (p < 0.001). Data collected from adult orthodontic re-treatment and first-treatment patients indicated that the demographic characteristics of these two groups were very similar. No significant differences were found between re-treatment patients and first-treatment patients in terms of motives for orthodontic treatment (p = 0.068), types of insurance (p = 0.615), and treatment satisfaction (p = 0.673). The study highlights the need for orthodontists and dentists to provide adequate information to patients about long-term retention and decision-making for orthodontic treatment, especially for re-treatment.
... He measured the mesiodistal width of maxillary and mandibular teeth in models of 55 white female with excellent occlusions and obtained the ideal values of anterior tooth ratio and overall tooth ratio. Little's irregularity index (LII) aims to objectively quantify the misalignment of mandibular anterior teeth [10], which is gradually used in the analysis of irregularity of upper and lower teeth and the stability of curative effect now [11,12]. However, some studies have confirmed the low repeatability and reliability of LII measurement [13,14]. ...
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Background An ideal relationship of anterior teeth is closely related to postoperative function, stability, and aesthetics. Therefore, it is necessary to estimate the proportion of anterior teeth when communicating with patients about possible treatment plans and outcomes. This study aimed to establish a simple method for assessing the proportion of anterior teeth and to identify the standard ratio value to provide references for clinical work. Methods Five hundred fourteen patients were divided into derivation, standard, and validation datasets. We first deduced our novel simplified anterior tooth ratio (SATR) by finding the key teeth with the derivation datasets, then established standard values by measuring the standard models, and finally validated the diagnostic performance of SATR. Independent sample t-test was used to select key teeth. Pearson’s correlation analysis and linear regression analysis was used to test and verify the correlation between SATR and the anterior Bolton ratio. Chi-square test and diagnostic test were used to verify the diagnostic results using SATR. P values of < 0.05 were considered statistically significant. Results Patients with an abnormal anterior Bolton ratio were more likely to have variations in the maxillary and mandibular lateral incisors. Therefore, the ratio of maxillary and mandibular lateral incisors was chosen as a simple way to assess the anterior tooth ratio and was defined as SATR (simplified anterior tooth ratio). A positive correlation was observed between SATR and anterior Bolton ratio (r = 0.702, p < 0.001), with the linear regression equation as follows: y = 0.503 + 0.328x, x = SATR, y = anterior Bolton ratio. The standard value of SATR was established (85.69% ± 3.57%) and proven reliable in clinical practice. Conclusions The ratio of maxillary and mandibular lateral incisors can be used to estimate the anterior tooth ratio, which showed high reliability and efficiency.
... 3,9 However, the great majority of the studies evaluated short retention periods. 3,5,8,11,[13][14][15][16][17][18] Moreover, these researches were mainly performed using post-graduation programs sample, a design in which patients are treated by a varied sort of techniques or professionals and with several retention protocols. ...
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Introduction: In several conditions, outcome stability is a great challenge for Orthodontics. Previous studies have reported that relapse commonly occurs along the years after orthodontic treatment finishing. Objective: The aim of the present study was to evaluate in the long-term transversal dental arch changes of Class II division 1 patients treated with cervical headgear and fixed appliance. Methods: Plaster study casts of 20 patients treated with cervical headgear without dental extractions were 3D-scanned and evaluated in three distinct times: initial (T1), immediate post-treatment (T2) and long-term retention (T3 - minimum 20 years). Transversal teeth distance of maxillary and mandibular canines, premolars and first molars were measured. Results: A statistically significant increase during treatment was observed for all maxillary teeth transversal distances (p< 0.05). In turn, a significant reduction was observed in the long term (p< 0.05). For the mandibular teeth, canine transversal distance presented statistically significant constriction in the retention period (p< 0.05). Mandibular first molars distance was significantly expanded by treatment (p< 0.05) and remained stable in the long term. The changes observed for the other teeth or other times were considered not statistically relevant. Conclusions: For the accessed sample, transversal changes occurred during treatment and retention phases in Class II division 1 patients treated with cervical headgear and fixed appliance. Relapse was considered statistically relevant, even with the institution of a retention protocol.
... us, the use of permanent retainers appears to be the only way to maintain the ideal alignment of the teeth after orthodontic treatment [2,3]. Several factors are responsible for unwanted tooth movement after orthodontic treatment such as regeneration of periodontal tissue [4], changes related to growth and development after treatment [5], and type of treatment performed [6]. To prevent unwanted tooth movements, retainer wires are connected to the lingual surface of the maxillary and particularly mandibular incisors [1]. ...
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Objectives: This study aimed to assess the bond strength and deflection of four types of bonded lingual retainers. Materials and methods: In this in vitro, experimental study, 160 extracted, mandibular incisors were mounted in acrylic blocks in sets of two and randomized into four groups for bonding of 1.0.010 × 0.026-inch Bond-A-Braid®, 0.012 × 0.027-inch Retanium®TM, 0.038 × 0.016-inch Ortho FlexTech®, and 0.0175-inch three-strand retainer wires; 15 mm of passive wire was adhered to the lingual tooth surface using Transbond XT composite. The shear (SBS) and tensile (TBS) bond strength values were measured. The adhesive remnant index (ARI) score and deflection of wires were also determined under a stereomicroscope. Data were analyzed by the chi-square test and ANOVA. Results: The four groups were significantly different regarding the ARI scores (P < 0.05). Significant differences were noted between the three-strand and all other groups in deflection (P < 0.05). The Retanium group had significant differences with other groups in peak SBS (P < 0.05). A significant difference was found between the Retanium and Ortho Flex groups in break SBS (P < 0.05). Significant differences were also reported between the three-strand and all other groups in peak TBS (P < 0.05). Conclusion: The Retanium retainer had the maximum SBS, while the three-strand retainer had the maximum TBS. The three-strand and Retanium wires can probably better tolerate intraoral forces and have higher resistance to fracture due to having higher TBS. Also, the three-strand wire had lower deflection rate, which highlights its higher resistance to occlusal forces. Retanium and Ortho FlexTech wires had the most favorable failure modes.
... Even when a well-functioning occlusion is achieved, orthodontic relapse (the tendency of teeth to return to their pretreatment positions) is a common finding. 1 Orthodontically moved teeth tend to move posttreatment. [2][3][4][5][6][7][8] This process has been linked to unfavorable occlusion, incomplete correction, tooth morphology, compensatory eruption, and growth. 9 A complicating matter is that increasing incisor irregularity can be seen in patients who have never received orthodontic care. ...
Article
Introduction The purpose of this study was to analyze any posttreatment changes in the positions of mandibular anterior teeth retained by 2 different fixed retention methods (rigid or flexible) and their effectiveness in minimizing postorthodontic tooth movement. Methods Thirty patients were selected for inclusion in this retrospective study. Group I consisted of 15 patients with 0.032-in stainless steel rigid retainers bonded to canines only. Group II consisted of 15 patients with 0.0215-in twisted stainless steel flexible retainer bonded to all mandibular anterior teeth. Geomagic Control (3DS Systems, Rock Hill, SC) software was used to quantify the changes between selected points. Paired t test was used for intragroup comparisons in all 3 coordinates, and an independent-sample t test was used for intergroup comparison. Results In the transverse dimension, significant intergroup differences were found in displacements of distoincisal points of the right lateral (P <0.05) and left central incisors (P <0.01). In the sagittal dimension, significant intergroup differences were found in the displacements of mesioincisal point of the right central incisor (P <0.05) and distoincisal point of the left central incisor (P <0.01). Examining total displacement, there were significant intergroup differences in mesioincisal point on the right central incisor, distoincisal point on the left lateral incisor (P <0.05). Conclusions Our results suggested that central incisor contacts were more likely to shift with the rigid retainers, especially in sagittal and transverse dimensions. However, no statistically or clinically significant changes were noted in the third-order or vertical positions of the teeth with either retention method.
... Many retention strategies and types of retention devices have been adopted over the years; however, there does not seem to be a clear consensus on the optimal retention protocol (10). However, it is apparent that if retention is discontinued, there is an unpredictable tendency of teeth to malalign again (11)(12)(13). Whether it is due to relapse of the original malocclusion or as a result of the above described physiologic changes of the dentition, is of little concern to the patient, whose main interest is usually to maintain ultimate aesthetics in the anterior region. When irregularities occur again, it is quite common that patients ask for a solution and retreatment may be necessary. ...
Article
Objectives This study aimed to compare the immediate influence of four commonly used retainer wires on tooth mobility following orthodontic treatment with fixed appliances. Materials and Methods Eighty patients after orthodontic treatment were assigned to four study groups (n = 20 in each group). Groups were provided with directly bonded fixed retainers—0.0150″ (group A), 0.0175″ (group B), 0.016 × 0.022″ (group C), and 0.0215″ (group D). Tooth mobility was measured using the Periotest device at two times—after removal of fixed appliance (T1) and after bonding of the retainer (T2). Values of tooth mobility, ‘Periotest values’, were analysed between groups and compared with the physiologic tooth mobility in a control group of untreated patients (n = 65). Kruskal–Wallis H, Mann–Whitney U, Dunn’s test, Fisher’s exact test, and binary logistic regression tests were used to analyze the data. Results Tooth mobility after orthodontic treatment was significantly increased. While canines remained within normal range of tooth mobility, values for incisors increased on average to the first degree of tooth mobility (slight mobility). Logistic regression analysis identified age as a significant predictor for increased tooth mobility (P = 0.032) with odds ratio 1.065 (95% CI 1.005–1.128), with mobility increasing with age. After bonding of the retainer in all four groups, the tooth mobility was reduced to values which were not significantly different form normal physiological values found in the control group (P > 0.05). There were no differences in the amount of change or in tooth mobility values at T2 between the different types of bonded retainers. Limitations Age of subjects in the control group was significantly higher than that in the study groups. An alternation method was used instead of randomization to distribute the four different types of retainers. Conclusions All of the retainer wires were able to successfully reduce the increased tooth mobility caused by orthodontic treatment to normal levels. The values of tooth mobility after placement of retainers were within the range of physiologic tooth mobility.
... Walau bagaimanapun, pengaruh tempoh fasa pengekalan kepada perubahan tersebut tidak disiasat dalam kajian ini. Perubahan kelebaran lengkung arkus yang ketara selepas rawatan ortodontik juga dilaporkan oleh kajian lain yang berjangka panjang (Sadowsky et al. 1994). Oleh itu, fasa pengekalan adalah sangat penting demi kestabilan hasil rawatan ortodontik. ...
Article
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ABSTRAK Fasa pengekalan adalah asas dalam rawatan ortodontik. Lebih kurang 70% pesakit mengalami kambuh semula selepas rawatan ortodontik. Risiko kambuh semula dapat dikurangkan dengan penggunaan aplians penahan yang sesuai dengan keadaan klinikal pesakit sebelum rawatan dan berdasarkan ciri-ciri aplians penahan. Apabila aplians penahan boleh tanggal diberi, tanggungjawab menjaga kestabilan gigi terletak pada pesakit. Idea terkini telah diusulkan bahawa aplians penahan yang boleh ditanggalkan harus dipakai selama-lamanya untuk mengekalkan hasil rawatan. Oleh itu, pemahaman terhadap ciri-ciri pengekalan aplians penahan gigi yang boleh ditanggalkan adalah penting untuk meningkatkan kepatuhan dan kepuasan pesakit. Artikel ini mengaji aplians penahan gigi yang boleh ditanggalkan dan fokus dalam perkara termasuk pilihan kegemaran di kalangan doktor pergigian, tahap penerimaan pesakit, keberkesanan aplians, kepatuhan pesakit, dan juga rejim fasa pengekalan. Pencarian artikel secara elektronik dilakukan di "PubMed/ MEDLINE", "ScienceDirect" dan "Scopus database". Pencarian telah dilakukan hingga Jun 2020 menggunakan pelbagai kata kunci termasuk aplians penahan ortodontik, "Hawley", terbentuk secara vakum dan pengekalan. Di antara 248 penerbitan yang dicari, sebanyak 56 penerbitan akhirnya dimasukkan. Dua puluh tujuh kajian adalah kajian jenis pemerhatian (6 prospektif; 16 keratan rentas, 4 retrospektif, dan 1 siri kes), 14 eksperimen, 14 artikel ulasan, dan satu pendapat. Walaupun terdapat banyak ulasan mengenai aplians penahan yang boleh ditanggalkan, kini terdapat beberapa artikel yang penting telah diterbitkan baru-baru ini. Bukan itu sahaja, garis panduan yang terkini mengenai rejim pengekalan juga sangat diperlukan. ABSTRACT Retention phase is fundamental in orthodontic treatment. Around 70% of patients are subjected to relapse post-orthodontic treatment. The risk of relapse can be minimized by prescribing a retainer suitable to a patient's pre-treatment clinical condition and based on retention characteristics of retainers. When removable retainers are prescribed, responsibility of maintaining tooth stability lies on patients. Recent idea has been proposed that removable retainer should be worn indefinitely in order to maintain the treatment result. Therefore, the understanding of retention characteristics of removable retainers is important for promoting patient compliance and satisfaction. This article focuses on reviewing the use of removable retainers in relation to preferences among clinicians, patient acceptability, effectiveness, compliance, as well as retention regimes. An electronic search was conducted in the PubMed/MEDLINE, ScienceDirect and Scopus database. The search was performed up to June 2020 using a variety of keywords including orthodontic retainers, Hawley, vacuum formed and retention. Among the 248 publications that were initially searched, total of 56 publications were finally included. Twenty-seven were observational (6 prospective; 16 cross-sectional, 4 retrospective, and 1 case series), fourteen experimental, fourteen review articles, and one opinion piece. Although quite a number of reviews on removable retainers were available, several significant papers have been published recently. Furthermore, a guideline on retention regime is warranted.
... Most studies agree that in an average patient, the maxillary anterior segment does not need dual retention, in that removable retention is sufficient. 52- 55 Canuto and coauthors reported that in 30% of treated subjects, there was a relapse causing maxillary irregularity during the post-retention period, 54 but the degree and nature of relapse was not necessarily associated with some initial outcome tooth position irregularities. The generally accepted theory behind a maxillary anterior relapse is based on an association between posterior occlusal forces, and the periodontal reflex of the anterior teeth. ...
Article
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Ideal static occlusal relationships do not necessarily result in ideal functional occlusal relationships. Current Orthodontic outcome indexes assess and satisfy aesthetic and morphologic endpoints but do not measure or determine any functional occlusal relationships, or report on the quality of the occlusal contacts that follow tooth movement. The T-Scan 10 Computerized Occlusal Analysis system can measure the occlusal contact distribution, can diagnose both static and dynamic functional occlusal relationships following orthodontic treatment, and can aid in the diagnosis of TMD/Occluso-muscle disorder patients. Comprehensive evidence supports the use of T-Scan analysis as an outcome measure in conjunction with the well-accepted means of registering occlusion (articulating paper, shimstock, occlusal wax, stone dental casts). This manuscript presents a rationale and a treatment protocol for the use of T-Scan in Orthodontics. It details T-Scan implementation during the initial examination, the active treatment appointments in extraction and non-extraction orthodontic treatment, before debonding the fixed orthodontic appliances, and during the settling and retention stages. TScan occlusal force and timing data sets can guide tooth movement decision making to improve functional occlusal contact interrelationships, optimize the occlusal balance and the functional posterior disclusion, speed up orthodontic treatment, and increase the long-term stability of the orthodontic outcome to prevent relapse.
... expansion of the posterior teeth [1]. This could support the stability concerns, as the available relapse data showed that premolar expansion and maintaining the intercanine width is advantageous for stability purposes, as expanded intercanine widths tend to decrease toward pretreatment values [33][34][35][36][37]. ...
Article
Objectives The purpose of this study was to evaluate the dental, skeletal, and soft-tissue change in crowding cases treated with nonextraction approach using the Damon system. Materials and methods The sample included 20 patients, with an average age of 17.8 ± 3.7 years, selected on the basis of pretreatment class I skeletal and molar relationships with an acceptable soft tissue facial profile, and a moderate crowding range between 4.0 and 9.0 mm for the maxilla and 2.0 and 6.0 mm for the mandible. None of them had received any orthodontic treatment before, or had extraction or any congenital anomalies such as supernumerary teeth. Results The evaluation of the study was performed by detecting the dental, skeletal, and soft tissue changes between pretreatment and post-treatment study models and lateral cephalometric radiographs. The paired t-test was used for statistical analysis. The treatment required 20.7 ± 2.2 months to be finished, with an average of 13.8 ± 1.5 appointments. Conclusion The results of this study revealed that the correction of crowding was achieved through expansion of the dental arches and mandibular incisors proclination.
... Crowding of lower incisors has a remarkable tendency to relapse [1,2] regardless of orthodontic techniques [3] and duration [4]. Long-term retention with fixed retainers which is independent of patient's compliance seems to be a reasonable solution to overcome this problem but unfortunately, an overall bond failure rate of 0.1 to 53% [5,6] usually at the wire/composite interference had been reported in the literatures [5]. ...
Article
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Background: Long-term retention with fixed retainers with a high success rate seems to be a reasonable solution to minimize or prohibit relapse of orthodontic treatment. Methods: Two hundred sixty patients between 13 and 30 years old were recruited for this study. The 0.0175 stainless steel twisted wire (G&H Orthodontics, USA) was compared with a single-strand ribbon titanium lingual retainer wire (Retainium, Reliance orthodontics, USA) was used. When treatment was completed, the retainers were bonded from canine to canine in the mandibular arch of the participants. In the follow-up visits, the patients were recalled every 3 months during the 24 months. Detachments, the time of debonding, and side effects were recorded. Statistical analysis was performed by a blinded statistician using a statistical package for Social Science (SPSS, Version20). After descriptive statistics, Kaplan-Meier analysis was performed to measure the survival rates of each retainer. P value < 0.05 was considered as significant. Results: Finally, 138 patients who received twisted wire splint and 112 patients who received ribbon wire were included in the analysis. The average duration of success was about 23 months for twisted wire and ribbon wire, according to the Kaplan-Meier estimates. The analysis showed no significant overall difference between the treatments (p = 0.13). Failure rates in terms of detachments in all groups occurred at the enamel junction, and it was 25 in twisted retainer group (18.1%) and was 10 in ribbon retainer group (8.9%); the Kaplan-Meier analysis test detected a significant difference in the failure rates between the groups (p = 0/006). Conclusions: Although the conventional twisted stainless steel wire and single-strand titanium flat metal ribbon wire as fixed orthodontic retainers have the same clinical effects, it was shown that the ribbon wire has less failure in terms of detachments.
... If the tooth material to its supporting basal arch is deficient then palatal expansion procedures can be held. Especially with anteroposterior movement of the arches (upper arch distally, lower arch mesially) upper palatal expansion procedures also have affect on the lower dentition and lower arch expansion is seen in these cases (11,12,13). ...
... Rapid relapse might possibly be due to a rebound in PDL compression (49) . Possibly, relapse energy stored in the collagenous periodontal and transseptal fiber systems was gradually released after spring removal (50,51) , resulting in faster and greater relapse in the first week. As the energy dissipated, the speed and extent of relapse stepped down. ...
... Prolonged retention of the lower labial segment, until the end of facial growth, may reduce the severity of future lower incisor crowding. 6 ...
Article
Retention is normally required after active orthodontic tooth movement in order to maintain tooth position and minimize the effects of age-related changes to the dentition. The aim of this article is to define stability, retention and relapse with reference to the literature and to review the evidence with regards to clinical effectiveness of different types of fixed and removable retainers and wear regimens, with emphasis on systematic reviews and Randomized Controlled Trials (RCTs). Furthermore, to discuss the general dental practitioner's role and responsibility in managing patients after active orthodontic treatment.
... Little's Irregularity Index has long been used to evaluate the post-retention stability; and recently, the orthodontists have extended its inclusion for maxillary arch to evaluate the effects of various brackets (7,8), retainers (9)(10)(11), and treatment modalities (11,12). reached in the literature. ...
Article
Objective: This study aimed to assess intra-examiner and inter-examiner reproducibility in irregularity index measurements. Methods: Twenty plaster casts of moderately crowded arches were randomly selected, and five contact point displacements (CPD) at lower anterior segment (through no. 33 to no. 43) were recorded using digital calipers on two different time points by three examiners to determine irregularity index (sum of five CPDs). To evaluate intra-examiner and inter-examiner differences, paired t-test and analysis of variance were used, respectively. Correlation analyses were performed between examiner pairs, and intra-class correlation coefficients (ICC) were determined. Statistical significance was set at p≤0.05. Results: Only a few of the repeated measurements of examiners showed significant differences (p≤0.05). All researchers were consistent in repeated measurements (p=0.000), and ICCs ranged between 0.916 and 0.986. For one CPD measurement, a statistically significant difference was detected among examiners (p=0.020). High correlation was found for inter-examiner repeatability (p<0.05), and ICCs ranged between 0.739 and 0.984. But when the difference of 1.5 mm among measurements was set as clinically relevant, the percentages of these values for repeated measures were 15%, 5%, and 45% for examiner 1, 2, and 3, respectively. These percentages were 25%, 80%, and 65% for examiner pairs. Conclusion: Irregularity index may be a misleading index to determine anterior alignment especially when measuring small CPD.
... Yet, in some cases, teeth begin to relapse to their original position even after orthodontic retention. It has been suggested that a relapse force is generated during orthodontic tooth movement and stored in the periodontal and transseptal fiber systems [2]. After the orthodontic appliance is removed, the relapse force is released, and the teeth begin to move back to their original positions [3]. ...
Article
Full-text available
Orthodontic relapse after orthodontic treatment is a major clinical issue in the dental field. However, the biological mechanism of orthodontic relapse is still unclear. This study aimed to establish a mouse model of orthodontic retention to examine how retention affects the rate and the amount of orthodontic relapse. We also sought to examine the role of osteoclastogenesis in relapse using an antibody to block the activity of M-CSF, an essential factor of osteoclast formation. Mice were treated with a nickel-titanium closed-coil spring that was fixed between the upper incisors and the upper-left first molar to move the first molar in a mesial direction over 12 days. Mice were randomly divided into three groups: group 1, no retention (G1); group 2, retention for 2 weeks (G2); and group 3, retention for 4 weeks (G3). In G2 and G3, a light-cured resin was placed in the space between the first and second molars as a model of retention. Orthodontic relapse was assessed by measuring changes in the dimensions of the gap created between the first and second molars. To assess the activity and role of osteoclasts, mice in G3 were injected with anti-c-Fms antibody or PBS, and assessed for changes in relapse distance and rate. Overall, we found that a longer retention period was associated with a slower rate of relapse and a shorter overall amount of relapse. In addition, inhibiting osteoclast formation using the anti-c-Fms antibody also reduced orthodontic relapse. These results suggest that M-CSF and/or its receptor could be potential therapeutic targets in the prevention and treatment of orthodontic relapse.
... Relapse has been the subject of many studies. [3][4][5] The reasons for relapse can be varied such as periodontal force, [6] patient's growth pattern continuing after the treatment, type of treatment performed, type of the retainer [7] and the duration of treatment, third molar eruption after treatment, muscular imbalance after the treatment, and noncompliance in retention protocol. ...
... expansion of the posterior teeth [1]. This could support the stability concerns, as the available relapse data showed that premolar expansion and maintaining the intercanine width is advantageous for stability purposes, as expanded intercanine widths tend to decrease toward pretreatment values [33][34][35][36][37]. ...
... Consequently, a retention time of about 2 years is probably sufficient, and tooth movements after those years are considered to be natural physiologic changes. Sadowsky et al 32 showed that an average period of 8.4 years with a fixed mandibular retainer was more favorable than shorter retention times in other studies. It seems that life-long retention for the mandibular anterior segment is needed. ...
Article
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Introduction: The aim of this work was to analyze the dental and skeletal changes in patients treated with fixed orthodontic appliances with or without retention appliances, and to compare the changes with untreated subjects. Specifically, mandibular incisor irregularity was analyzed. Methods: A total of 105 children who had undergone orthodontic treatment with fixed appliances in both jaws were examined in 2 groups: 64 had a lingual mandibular retainer and 41 had no retainer. Retention time was 2.7 ± 1.5 years. The untreated group consisted of 25 subjects. Measurements were done on study casts and lateral head radiographs before and after treatment and 6 and 12 years after treatment. The Little irregularity index (LII) was the most important variable. Results: No differences were found in LII 12 years after treatment between the group that had a retainer and the group without a retainer after treatment. In the untreated group, LII was increased over time, but not to the same extent as in the treated groups. Correction of overjet and overbite was stable long-term. At the last examination, the amount of overjet was almost the same in all 3 groups. Conclusions: The routine use of mandibular retainers for 2 to 3 years does not appear to prevent long-term relapse. If the patient wants to constrain natural development and changes, lifelong retainers are needed.
... Sabit retainer dışardan görünen bir aparey olmadığın-dan ne zaman çıkarılacağına karar vermek zordur. Birçok klinisyen tarafından 10 yıl kadar uzun bir süre ağızda tutulması önerilmektedir (35)(36)(37)(38). Bu uzun dönem retansiyon periyodları, üçüncü molarların sürmesini beklerken ve postpubertal büyüme sürecinde yararlıdır (35,39). ...
Article
Bitirme ve retansiyon, ortodontik tedavinin birbirini takip eden iki önemli fazıdır. Optimum bitirme kriterlerinin sağlanmış olması ve tedavi edilmiş dentisyonun ve onu etkileyen çevresel etkenlerin iyi değerlendirilmesi, uygun retansiyon prosedürünün belirlenmesi açısından kritik öneme sahiptir. Ortodontik tedavinin retansiyon aşamasında, sabit lingual retainerların kullanımı günümüzde sıklıkla tercih edilmektedir. Sabit retansiyonda daha çok tercih edilen iki tip tel vardır. Kalın retainer teli mandibuler kanin-kanin arası sadece kanin dişlere bondlanarak kullanılır, ince çok sarımlı tel ise retansiyonu istenen alandaki bütün dişlere bondlanarak kullanılır. Lingual retainera ek olarak bazı spesifik durumlar için kısa labial sabit retainer kullanımı da uzun dönem tedavi sonuçlarını iyileştirebilir. Sabit retainer kullanımı köprü protezi veya implant boşluğunun korunmasında da iyi bir seçimdir. Sabit retainerlarla ilgili uzun dönem tecrübeler memnun edicidir. Bu apareylerin ağızda tutulma süresi hastalar tarafından sıklıkla merak edilen bir konudur. Eğer uygulanan retainer teli stabilse, tedavi sonuçları korunuyor ve hasta hijyen prosedürlerini uyguluyorsa, sabit retainer teli diş yüzeylerinden çıkartılmamalıdır.
Chapter
Orthodontic outcomes have been extensively graded to ensure optimal aesthetic and functional results. Several grading systems are used worldwide, with the most being the American Board of Orthodontics objective grading system (ABO-OGS) and the peer assessment rating (PAR). The ABO-OGS has been shown in recent orthodontic studies to highly correlate with T-Scan digital occlusion analysis parameters, where post-orthodontic patients demonstrated worse excursive movement parameters compared to non-orthodontically treated patients. Additionally, one static occlusion T-Scan parameter (the Anterior/Posterior % ratio) was correlated to the presence of significant anterior overbites and the presence of a Class II Angle Classification. As such, the Specific Aims of this chapter are to describe the T-Scan parameters of orthodontic patients treated with different techniques (fixed appliances on the buccal or lingual, and clear aligner treatment), and compare those results against the differing orthodontic grading systems. Moreover, this chapter will describe in detail how fixed appliance orthodontic therapy when combined with T-Scan digital occlusal analysis improves orthodontic treatment outcomes prior to debanding. Additionally, this chapter will illustrate how T-Scan, when used during clear aligner treatment planning, and in the refinement stages when additional aligners are often required, can markedly improve clear aligner outcomes, as well.
Article
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Post‐treatment change in the form of true relapse and physiological and maturational effects is common following orthodontics. The unpredictable nature of these manifestations dictates a conservative, near‐universal approach to retention. Both fixed and removable forms of retention are popular with the latter constrained by variable levels of adherence particularly in the medium‐ to long‐term. Fixed retention may offer a more predictable means of preservation of orthodontic outcomes; however, this advantage is offset by the requirement for prolonged supervision and the potential for adverse changes including periodontal breakdown. Nevertheless, while examples of severe complications are common, a clear causal relationship between intact, passive retainers and periodontal issues does not appear to exist. Nevertheless, the importance of diligent maintenance and careful supervision during fixed retention, in particular, cannot be disregarded.
Chapter
Application of orthodontic forces is concomitant with changes in the surrounding bone and periodontal ligament and consequential release of multitude of mediators in gingival crevicular fluid (GCF), saliva, and other body fluids at varied time points. Although the evidence of clinical tooth movement has progressed with the advent of newer three dimensional (3D) diagnostic aids, the evidence related to underlying cellular and molecular changes concomitant with release of biomarkers in the paracrine environment, is slowly and steadily evolving. The current lecture will highlight the importance of structured critical appraisal of evidence related to biomarkers in tooth movement to give valuable insights into the best orthodontic practices. These clinical implications may include but is not exhaustive of the magnitude and type of force, force re-activations, and growth status of the patients. The lecture also entails current research trends on bio-orthodontics by presenting a viewpoint on newer realms like microRNAs (miRNAs) in body fluids, which work as RNA-interfering systems or gene silencing entities, and may have significant impact on accelerating the tooth movement or in personalised patient care.
Article
Background: The aim of this trial was to assess the effect of enamel sandblasting in addition to the acid-etch technique in reducing first-time failures of fixed mandibular retainers placed over a 12-month period. Materials and methods: Ethical approval was obtained. Participants were recruited in a single private practice. The primary outcome of this study was any first-time failure of the mandibular fixed retainer assessed at three timepoints over a 12-month period. Three consecutive teeth either on the left or right side (from lower canine-lower central incisor) were randomly allocated to the intervention (sandblasting) and the control (non-sandblasted). Randomization was performed using a centralized randomization service. The patients were randomized in blocks of four and eight with allocation concealment secured by contacting the sequence generator for group assignment. Blinding of either the patient or clinicians was not possible at time of placement of the mandibular retainer. Results: One hundred and ninety-seven participants were randomized to receive enamel sandblasting (intervention) and non-sandblasting (control) in the region of the six anterior mandibular teeth in a split-mouth fashion. Participants were recruited between December 2018 to October 2020. The data for all participants were analysed resulting in 394 observations. Overall, the risk of first-time failure was 11.4%. No difference in first-time failures was observed between the intervention (sandblasting) and control (non-sandblasting) groups [hazard ratio (HR), 1.05; 95% confidence interval (CI), 0.59, 1.88, P = 0.88]. Males had a higher instant probability of first-time failures (HR, 3.18; 95% CI, 1.65-6.14; P < 0.01). Participants with a fair level of co-operation had a lower instant probability of first-time failures (HR, 0.37; 95% CI, 0.16-0.86; P = 0.02). There were no harms reported to either the participant or their dentition. Conclusions: No difference in the first-time failures of mandibular bonded retainers placed with conventional etch-bond technique with or without enamel sandblasting was observed. The overall risk of first-time failure was 11.4%. Registration: This trial was not registered prior to trial commencement.
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One of the most challenging phase for an orthodontist is to retain the corrections achieved during the course of orthodontic treatment. Retainers are passive orthodontic appliances that help in maintaining and stabilizing the position of teeth long enough to permit reorganization of supporting structures after the active phase of orthodontic therapy. This article provides a comprehensive review about the various types of orthodontic retainers available today.
Article
strong>Introduction: The fixed lingual bonded retainers have gained preference over removable retainers because they are more aesthetic, comfortable, convenient and free of patient compliance, but their periodontal effects, the incidences of breakages and failure to maintain incisor alignment are the some concerns. Therefore, this study aims to systematically evaluate the efficiency of retention and periodontal effects of lingual bonded retainers in orthodontically treated patients. Materials and Methods: The PRISMA guidelines were followed. The databases of Cochrane Library, PubMed and Google Scholar were systematically searched. All human, original research studies in English evaluating the fixed lingual bonded retainers, in orthodontically treated patients, in single group or in comparison with different fixed lingual bonded retainers, with or without control were included. All articles were subjected to assessment of risk of bias. Results: A total of 17 studies were selected meeting the inclusion criteria. These were divided into two Group 1 - addressing the periodontal status; Group 2 - addressing the lower incisor stability. The 7 selected studies for group 1, reported that periodontal effects like gingival inflammation, plaque and calculus accumulation are associated with all kinds of lingual bonded retainers, but more in multistranded retainer. The lower incisor stability and alignment during retention phase was shown to be very efficient with multistranded retainers compared to others, in the 14 selected studies for group 2. From the 17 selected studies, 8 studies had a high risk of bias, 5 studies had a medium of bias and 4 studies had a low risk of bias. Conclusion: Even though newer types of retainers are being introduced to improve the survival rate, the multistranded retainers still prove to be a good choice with respect to maintenance of incisor alignment.
Article
Purpose To analysis, daidzein increases the expression of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor 2 (Runx2) after experimental tooth movement (EXTM). Materials and Methods 36 Wistar rats were randomly divided into the EXTM group and EXTM with daidzein group (EXTM+DZ group). After EXTM, the rats in the EXTM+DZ group were treated with daidzein (10 mg/kg/day). Micro-computed tomography (CT) analysis revealed the bone mineral density (BMD), ratio of bone volume to tissue volume (BV/TV), and ratio of relapse. Histopathological changes were examined by immunohistochemical staining for BMP-2 and Runx2. Human PDLCs were subjected to tension force and treated with 10 μg/mL daidzein. The expression of BMP-2 and Runx2 by daidzein was confirmed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Results The EXTM+DZ group showed a significantly decreased ratio of relapse and increased BMD and BV/TV as compared to the EXTM group. The ratio of BMP-2 – and Runx-2 –positive cells in the EXTM+DZ group was higher than that in the EXTM group. Moreover, daidzein upregulated the mRNA expression and protein levels of BMP-2 and Runx2 in a time-dependent manner. Conclusion These results suggested that daidzein decreased the ratio of relapse through BMP-2 and Runx2 expression.
Article
Full-text available
One of the most challenging phase for an orthodontist is to retain the corrections achieved during the course of orthodontic treatment. Retainers are passive orthodontic appliances that help in maintaining and stabilizing the position of teeth long enough to permit reorganization of supporting structures after the active phase of orthodontic therapy. This article provides a comprehensive review about the various types of orthodontic retainers available today.
Article
Introduction: Deep overbite is one of the most common malocclusions and is the most difficult to treat successfully. The real challenge remains the stability of long-term deep overbite correction. A search through the scientific literature revealed only one systematic review on this subject. Given the recent publications on the stability of deep bite correction and the development of new processes designed to avoid relapse of these treatments, this one existing systematic review needs to be updated. The purpose of the present systematic review is to evaluate the long-term stability of deep overbite correction. Materials and methods: Electronic databases were searched and nonelectronic journals were manually explored for papers on long-term stability and relapse of deep overbite correction. Articles deemed appropriate for inclusion in this review were selected and analyzed. Their scientific quality was assessed and the data they contained were extracted and summarized. Results: The rate of deep overbite relapse was 47.27%. Patients treated with the straight wire appliance showed a 67.74% relapse rate whereas those treated with the Ricketts biological progressive segmented mechanics appliance displayed a 30.38% rate. Subjects treated towards the end of adolescence presented a 14.3% rate of deep overbite relapse whereas those treated in their early teens or in adulthood had a deep overbite relapse rate of 30% and 30.8%, respectively. Intramuscular injections of botox helped obtain 100% stability in maxillofacial surgery to correct deep bite. Conclusion: Age at initiation of treatment and treatment technique are two factors impacting the long-term stability of deep overbite correction.
Article
Aim The study was conducted with the aim of evaluating general retention practices, current trends, and difficulties with vacuum-formed retainers (VFR) by the orthodontists in India. Method A questionnaire link was generated using the Google Forms App in total with 28 multiple-choice questions representing general retention practice in the first part and VFR practice in the second part. Results The overall response rate was 54.4%. On receiving of the completed questionnaires, the data were statistically analyzed. Most practitioners prescribe retainer wear for 1 to 2 years irrespective of the age of the patients, with 2 to 4 years of follow-up. Also VFR of 1 mm thickness with full-occlusal coverage extending 1 to 2 mm beyond the gingiva is recommended immediately after debonding with full-time wear. Discoloration and breakage within 6 to 9 months of VFR wear are commonly encountered problems. In case of relapse with VFR, practitioners prefer to switch over to removable retainers, which shows the major drawback with VFR usage. Conclusion Removable and fixed retainers are currently the main preferences of retainers. VFR as the esthetic alternative will replace other retainers in the future provided problems with its usage are resolved.
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Orthodontic relapse after orthodontic treatment is a major clinical issue in the dental field. However, the biological mechanism of orthodontic relapse is still unclear. This study aimed to establish a mouse model of orthodontic retention to examine how retention affects the rate and the amount of orthodontic relapse. We also sought to examine the role of osteoclastogenesis in relapse using an antibody to block the activity of M-CSF, an essential factor of osteoclast formation. Mice were treated with a nickel-titanium closed-coil spring that was fixed between the upper incisors and the upper-left first molar to move the first molar in a mesial direction over 12 days. Mice were randomly divided into three groups: group 1, no retention (G1); group 2, retention for 2 weeks (G2); and group 3, retention for 4 weeks (G3). In G2 and G3, a light-cured resin was placed in the space between the first and second molars as a model of retention. Orthodontic relapse was assessed by measuring changes in the dimensions of the gap created between the first and second molars. To assess the activity and role of osteoclasts, mice in G3 were injected with anti-c-Fms antibody or PBS, and assessed for changes in relapse distance and rate. Overall, we found that a longer retention period was associated with a slower rate of relapse and a shorter overall amount of relapse. In addition, inhibiting osteoclast formation using the anti-c-Fms antibody also reduced orthodontic relapse. These results suggest that M-CSF and/or its receptor could be potential therapeutic targets in the prevention and treatment of orthodontic relapse.
Article
Background: Although post-treatment mandibular alignment has been extensively investigated, the findings remain controversial. Objectives: The objective was to assess mandibular alignment changes, as measured by the irregularity index, of patients who underwent full-fixed orthodontic treatment and were followed up at least 1 year after retention. Search methods: MEDLINE, EMBASE, and Cochrane library, in addition, the reference lists of included studies, were screened. The search was conducted up to April 2018. Selection criteria: The study designs included both interventional and observational studies of orthodontic patients who received either extraction or non-extraction treatment. Data collection and analysis: The interventional studies were assessed using the Cochrane Collaboration's risk of bias assessment tool. The quality of the observational studies was evaluated using National Institution of Health quality assessment tools. The first two authors independently applied the eligibility criteria, extracted the data, and assessed the risk of bias. Any conflicts were resolved with consensus discussion with the third author. Results: The search retrieved 11 326 articles, 170 of which were assessed for eligibility. There were 44 studies included in the qualitative assessments and 30 in the meta-analyses. The studies included 1 randomized control trial (RCT) and 43 observational studies. The RCT was judged to have a high risk of bias and all of the observational studies had either fair or poor quality. The meta-analysis was based on studies judged to be of fair quality, including a total of 1859 patients. All meta-analyses were performed using random-effect models. The standardized mean difference between post-treatment and post-retention irregularity was 1.22 (95% CI, 1.04-1.40) and 0.85 (95% CI, 0.63-1.07) after extraction and non-extraction treatments, respectively. There was a substantial heterogeneity for the extraction (I2 = 75.2%) and non-extraction (I2 = 70.1%) studies. The follow-up duration (1-10 versus 10-20 years) explained 33% of the heterogeneity, with longer follow-up studies showing more irregularity. Limitations: The quality of evidence provided by the studies was low. There was a risk of publication bias, and the search was limited to English language. Conclusions and implications: Post-treatment mandibular irregularity increases are limited. Irregularity increases are slightly greater in patients treated with mandibular premolars extractions, and in patients followed up over longer periods of time. Registration: The study protocol was not registered.
Article
Introduction: A retainer bonded to the lingual surfaces of the mandibular canines (3-3 retainer) is a widely used type of retention. Our aim in this study was to assess the effectiveness of the 3-3 mandibular lingual stainless steel retainer to prevent relapse of the orthodontic treatment in the mandibular anterior region. Methods: The sample consisted of the dental casts of 235 consecutively treated patients (96 boys, 139 girls) from the archives of the Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Center, The Netherlands, who received a 3-3 mandibular lingual stainless steel retainer at the end of active orthodontic treatment. The casts were studied before treatment (Ts), immediately after treatment (T0), and 2 years (T2), and 5 years (T5) posttreatment. Results: The main irregularity index decreased significantly from 7.2 mm (SD, 4.0) at Ts to 0.3 mm (SD, 0.5) at T0; it increased significantly during the posttreatment period to 0.7 mm (SD, 0.8) at T2 and 0.9 mm (SD, 0.9) at T5. The irregularity index was stable during the 5-year posttreatment period (T0-T5) in 141 patients (60%) and increased by 0.4 mm (SD, 0.7) in 94 patients (40%). The intercanine distance increased 1.3 mm between Ts and T0 and remained stable during the posttreatment period. Conclusions: The 3-3 mandibular lingual stainless steel retainer (bonded to the canines only) is effective in preventing relapse in the mandibular anterior region in most patients, but a relatively high percentage will experience a small to moderate increase in mandibular incisor irregularity.
Article
A quantitative method of assessing mandibular anterior irregularity is proposed. The technique involves measurement directly from the mandibular cast with a caliper (calibrated to at least tenths of a millimeter) held parallel to the occlusal plane. The linear displacement of the adjacent anatomic contact points of the mandibular incisors is determined, the sum of the five measurements representing the Irregularity Index value of the case. Reliability and validity of the method were tested, with favorable results. At the University of Washington, several clinical studies have been and are continuing to be performed, using this technique as one of several methods of assessing pretreatment status and posttreatment change. It is hoped that this article will aid the reader in understanding the rationale and utility of a simple quantitative tool which could be used in malocclusion assessment.
Article
Case records were evaluated for 30 patients who had undergone serial extraction of deciduous teeth plus first premolars followed by comprehensive orthodontic treatment and retention. Diagnostic records were available for the following stages: pre-extraction, start of active treatment, end of active treatment, and a minimum of 10 years postretention. All cases were treated with standard edgewise mechanics and were judged clinically satisfactory by the end of active treatment. Twenty-two of the 30 cases (73%) demonstrated clinically unsatisfactory mandibular anterior alignment postretention. Intercanine width and arch length decreased in 29 of the 30 cases by the postretention stage. There was no difference between the serial extraction sample and a matched sample extracted and treated after full eruption.
Article
Increasing mandibular arch length to resolve crowding has long been debated as a treatment method. Twenty-six patients with records obtained before treatment, after treatment, and a minimum of 6 years out of retention were assessed. All the patients showed a loss of treatment arch length increase with only 6 of 26 patients showing any gain over pretreatment dimensions. Width constriction was a consistent finding, as was crowding of anterior teeth after retention. In 89% the postretention record demonstrated clinically unsatisfactory alignment. Lateral cephalometric superimposition of mandibles showed variable molar and incisor change after retention. As teeth erupted after treatment, mesial molar movement and lingual tipping of incisors were the most common cephalometric findings.
Article
The aim of this study was to observe longitudinally the anterior region of the lower jaw when treating only the upper jaw. A comparison was made between a group of 35 children treated with extraction of the maxillary first premolars and a fixed appliance in the upper jaw and a control group of 19 untreated children. The treatment group was studied with plaster models on five occasions: before treatment, at the end of active treatment, at the end of retention, after one year out of retention and at the last registration, in total over about a seven year period. Cephalometric registrations were made before treatment and at the last registration. The control group was studied with plaster models and lateral head films during a period of nine years and their age at the last registration was the same as for the treatment group. The space loss in the anterior region of the lower jaw increased from a mean of 0.4 mm (s.d. 0.82) to 2.5 mm (s.d. 1.52) in the treatment group and from 0.1 mm (s.d. 0.16) to 0.5 mm (s.d. 0.81) in the control group: an extra space loss of 2.0 mm for the treatment group. The main increase was registered during treatment and after retention. Subjective ranking of the plaster models from the final registrations according to the amount of crowding in the lower anterior region also showed a significant difference between the treatment group and the control group, the treatment group showing the largest of crowding. In cases where maxillary protrusion is treated by extraction in the maxilla only, stabilization of the lower arch with fixed orthodontic appliances seems justified.
Article
The purpose of the study was to evaluate the result in adults of Class I malocclusion cases who had all their first premolars extracted as the sole treatment of space deficiency in the mixed or early permanent dentition. The mean age at premolar removal was 10½ years. Forty-two out of 44 cases were re-examined at a mean age of 30 years and 4 months. Observations of dental occlusion and oral health were compared to observations of control samples. The average malocclusion in the adults, as judged by a score method, was similar to that reported for an appliance-treated sample. Marked spontaneous arch alignment and residual space closure with age was seen in most cases. Despite earlier tooth removal, on average crowding developed to about the same degree as that of an non-extraction normal occlusion sample. No detrimental effects were seen with regard to overjet or overbite. Neither did the figures for lower incisor position at the follow-up examination differ from that of the normal occlusion sample. Although tipping of adjacent teeth towards the extraction site was frequent, especially in the mandible, no effect on marginal bone height was evident as judged by comparison with a nonextraction control sample. The results reveal a significant capacity for spontaneous improvements with age in dental arch morphology and relationship in extraction cases, provided that specific features have been looked for in case selection.
Article
Assessment of cases that had been out of retention a minimum of 10 years and had displayed generalized spacing of anterior teeth before treatment showed consistent reduction of arch length and intercanine width into adult years. Intercanine width constriction typically occurred while arch length decreased in every case, both width and length reduction being progressive with time. Crowding was minimal for the majority of cases; few demonstrated the severe crowding more typical of cases with pretreatment crowding.
Article
Pretreatment, end of treatment, 10-year postretention, and 20-year postretention records of 31 four premolar extraction cases were assessed to evaluate stability and relapse of mandibular anterior alignment. Crowding continued to increase during the 10- to 20-year postretention phase but to a lesser degree than from the end of retention to 10 years postretention. Only 10% of the cases were judged to have clinically acceptable mandibular alignment at the last stage of diagnostic records. Cases responded in a diverse unpredictable manner with no apparent predictors of future success when considering pretreatment records or the treated results.
Article
To assess the long-term stability of nonextraction orthodontic treatment, the dental cast and cephalometric records of 28 cases were evaluated. Thirty cephalometric and seven cast parameters were examined before treatment, posttreatment, and an average of almost 8 years postretention. Results showed overall long-term stability to be relatively good. Relapse patterns seen were similar in nature, but intermediate in extent, between untreated normals and four first premolar extraction cases. Significant decreases were seen in arch length and intercanine width during the postretention period despite minimal changes during treatment. Incisor irregularly increased slightly postretention; intermolar width, overjet, and overbite displayed considerable long-term stability. Mandibular incisor mesiodistal and faciolingual dimensions were not associated with either pretreatment or posttreatment incisor crowding. Class II malocclusions with large ANB values and shorter mandibular lengths showed increased incisor irregularity, shorter arch lengths, and deeper overbites at the postretention stage, suggesting that the amount and direction of facial growth may have been partially responsible for maturational changes seen during the postretention period.
Article
Assessment at least 10 years postretention of fifty-four cases previously treated in the permanent-dentition stage with first-premolar extractions, traditional edgewise mechanotherapy, and retention revealed considerable variation among patients. The long-term response to mandibular anterior alignment was unpredictable; no cephalometric parameters, such as maxillary and mandibular incisor proclination, horizontal and vertical growth amounts, mandibular plane angle, etc., were useful in establishing a prognosis. Few associations of value were found between cephalometric parameters and dental-cast measurements, such as overbite, arch length, intercanine width, and overjet. Only a slight tendency was found for incisor inclination to return toward the pretreatment value during the postretention period. It was possible to predict, on the basis of an analysis of pre- and posttreatment cephalometric records, those cases which had greater than 4 mm deepening of overbite postretention as well as those cases which had decreases of 3 mm or more in arch-length postretention. The practical use of these predictions were of limited clinical value, however.
Article
The dental casts of 65 untreated normal occlusions were evaluated to determine the nature and extent of the developmental maturation process of the normal dentition. Six dental parameters were examined in the mixed dentition (9 to 10 years), early permanent dentition (12 to 13 years), and early adulthood (19 to 20 years). Results showed decreases in arch length and intercanine width; minimal overall changes in intermolar width, overjet, and overbite; and increases in incisor irregularity. Females showed more severe changes than males. The individual changes found were not correlated to changes in any of the other parameters measured. No associations or predictors of clinical value were found. The changes found in a sample of untreated normals were similar in nature but lesser in extent than postretention changes found in a sample of treated cases.
Article
Adult changes in selected occlusal parameters are measured, with the study sample limited to 72 subjects with a history of malocclusion treated orthodontically 12 to 35 years previously. Variations were large. Most of the corrections were retained, with mean changes tending toward pretreatment values.
Article
The dental models of seventy-seven orthodontically treated patients were evaluated to determine the contribution of lower incisor tooth dimensions to their alignment many years after treatment. Tooth dimensions included the maximum mesiodistal (MD) and faciolingual (FL) dimensions and the shape ratio represented by MD/FL. Incisor alignment was assessed by means of Little's irregularity index, and all measurements were recorded to the nearest 0.1 mm with modified dial calipers. Multiple regression analysis revealed that the total contribution of all these lower incisor dimensions accounted for only 7.4% of the variability in their alignment, which was not statistically significant. A similar lack of association between lower incisor tooth dimensions and their alignment was found in a sample of eighty-six adults with untreated malocclusions. It therefore appears that the size and shape of the lower incisors do not significantly contribute to their alignment many years after orthodontic treatment.
Article
Assessment at least 10 years postretention of sixty-five cases previously treated in the permanent-dentition stage with first-premolar extractions, traditional edgewise mechanics, and retention revealed considerable variation among patients. The long-term response to mandibular anterior alignment was unpredictable; no variables, such as degree of initial crowding, age, sex, Angle classification, etc., were useful in establishing a prognosis. Typically, arch width and length decreased after retention, regardless of treatment expansion or constriction. Two thirds of the patients had unsatisfactory lower anterior alignment after retention. Cases that were minimally crowded before treatment usually became more crowded, while initially severe crowding cases usually moderated.
Article
The long-term stability of orthodontic treatment was evaluated in a group of ninety-six former patients who were treated between 12 and 35 years previously. Dental relationships were recorded on study models taken prior to orthodontic treatment, at the end of active treatment, and at long-term follow-up. A malocclusion score was developed for this study, and the over-all static occlusal relationships were categorized by defining an ideal range for eleven variables. Ninety of the ninety-six cases were within the ideal range at the end of treatment. Most of the cases showed an improvement of their malocclusions in the long-term stage. However, of the ninety-six subjects, sixty-nine (72 percent) had at least one variable outside our ideal range in the long-term follow-up. A moderately increased overjet and overbite was responsible in most instances for the result being outside the ideal range in the long term. The long-term result as compared to the original malocclusion exhibited increased overbite in 16 percent of the cases, increased mandibular anterior crowding in 9 percent of the cases, and increased overjet in 5 percent of the cases. The range of ideal, considering only the variables used in this study, will to some extent vary with the eye of the beholder. Therefore, the results of this study need to be interpreted accordingly. It is suggested that orthodontists be well aware of long-term changes in dental relationships many years after treatment and take this into account when advising patients as to the potential benefits of orthodontic treatment.
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