Orthodontic retention: A systematic review

Comparison of speech changes caused by four different orthodontic retainers: a crossover randomized clinical trial

OBJECTIVE

This study aimed to compare the influence of four different maxillary removable orthodontic retainers on speech.

MATERIAL AND METHODS

Eligibility criteria for sample selection were: 20-40-year subjects with acceptable occlusion, native speakers of Portuguese. The volunteers (n=21) were divided in four groups randomized with a 1:1:1:1 allocation ratio. The four groups used, in random order, the four types of retainers full-time for 21 days each, with a washout period of 7-days. The removable maxillary retainers were: conventional wraparound, wraparound with an anterior hole, U-shaped wraparound, and thermoplastic retainer. Three volunteers were excluded. The final sample comprised 18 subjects (11 male; 7 female) with mean age of 27.08 years (SD=4.65). The speech evaluation was performed in vocal excerpts recordings made before, immediately after, and 21 days after the installation of each retainer, with auditory-perceptual and acoustic analysis of formant frequencies F1 and F2 of the vowels. Repeated measures ANOVA and Friedman with Tukey tests were used for statistical comparison.

RESULTS

Speech changes increased immediately after conventional wraparound and thermoplastic retainer installation, and reduced after 21 days, but not to normal levels. However, this increase was statistically significant only for the wraparound with anterior hole and the thermoplastic retainer. Formant frequencies of vowels were altered at initial time, and the changes remained in conventional, U-shaped and thermoplastic appliances after three weeks.

CONCLUSIONS

The thermoplastic retainer was more harmful to the speech than wraparound appliances. The conventional and U-shaped retainers interfered less in speech. The three-week period was not sufficient for speech adaptation.

Comparative Analysis of Braces and Aligners: Long-Term Orthodontic Outcomes

Objectives

The purpose of this retrospective study was to evaluate the long-term results of orthodontic treatment with traditional braces and Invisalign, with a particular emphasis on treatment length, patient satisfaction, correction of malocclusion, and long-term stability.

Methods

Between 2020 and 2022, individuals who had orthodontic treatment at a tertiary care center had their data analysed. Patients with mild to severe malocclusions treated with conventional braces or Invisalign between the ages of 12 and 18 met the inclusion criteria. Assessments were done on results, length of treatment, degree of malocclusion, and long-term stability. With significance set at P < 0.05, statistical analyses comprised t-tests for treatment duration and Chi-square testing for malocclusion correction.

Findings

The mean treatment time for Invisalign was much shorter (18 months) than for conventional braces (24 months) (P < 0.001). With 88-90% success rates, both techniques demonstrated remarkable success rates in malocclusion treatment. Even though Invisalign was associated with a somewhat greater percentage of relapse instances, the difference was not statistically significant (P > 0.05).

Conclusion

In conclusion, Invisalign showed a much shorter treatment period than conventional braces, yet both showed excellent malocclusion correction. The choice of modality should be based on patient satisfaction, treatment objectives, and case complexity, taking into account the trade-offs between treatment length and potential variations in long-term stability.

Mechanical properties of combined packable and high-filled flowable composite used for the fixed retainer: an in vitro study

BACKGROUND

Clinicians often utilize both flowable and packable composites concurrently in bonding fixed retainers. Thus, this study aimed to assess the synergistic effect of these composites in the bonding process.

METHODS

This in vitro study divided specimens into three groups: flowable composite (nano-hybrid, Tetric N-Flow, Ivoclar Vivadent), packable composite (nano-hybrid, Tetric N-ceram, Ivoclar Vivadent), and combined use of flowable and packable composite. Shear bond strength (SBS), adhesive remnant index (ARI), and wire pull-out resistance were compared among the groups. Statistical analyses were conducted using ANOVA and Tukey tests to compare study groups. Additionally, Chi-square and Kruskal-Wallis tests were employed to analyze the ARI index among the groups.

RESULTS

ANOVA results indicated no statistically significant differences among test groups (P = 0.129) regarding SBS. However, a significant difference existed between flowable and packable composite groups (P = 0.01) regarding ARI scores. Among the study groups, flowable composite exhibited the highest frequencies of ARI scores of 1 and 2, whereas packable composite showed the highest frequency of ARI scores of 0. The combined group had higher frequencies of ARI scores of 0 and 1 compared to the flowable composite. The wire pull-out test revealed that the combined application of flowable and packable composite resulted in significantly lower detachments compared to the packable composite alone (P = 0.008). However, no significant differences were observed in the comparisons between the flowable-packable (P = 0.522) and combined-flowable (P = 0.128) groups.

CONCLUSION

The combined use of flowable and packable composites for fixed retainers demonstrated adequate shear bond strength and ideal ARI scores, suggesting it as a suitable adhesive system for bonding orthodontic fixed retainers.

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

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

Enhancing Orthodontic Renewal and Retention Techniques: A Systematic Review

Orthodontists have a variety of options available for retainers. Research in Orthodontics focuses on assessing outcomes important to clinicians; however, there is inconsistency in how these outcomes are selected and evaluated. This review sought to assess the effects of different orthodontic retainers on patients' quality of life (QoL). Various approaches were employed in this systematic review, and a thorough search was conducted across six databases. The review involved a comprehensive evaluation of six included studies, highlighting changes in dental structure post-treatment, emphasizing the role of extraction procedures and the quality of debonding in improving retention. The study identified key outcomes for orthodontic clinical trials, highlighting orthodontists' preferences for specific retainer types. Moreover, it discussed the impact of sociocultural influences on retention care. Involving patients actively in discussions about whether to end or extend the retention phase was deemed essential. Noteworthy improvements in occlusal outcomes were linked to extraction treatments. Gender and malocclusion severity influenced QoL before and after orthodontic treatment. The degree of improvement observed in the Class III malocclusion group was comparatively lower than that in the Class I and Class II groups. Orthodontic treatment was found to yield favorable psychological outcomes, as evidenced by notable enhancements in self-esteem and social engagement among individuals. Fixed appliances were shown to negatively affect oral health-related quality of life (OHRQoL), particularly for those with aesthetic and functional concerns. A consensus has been reached on the essential themes and outcomes that should be incorporated in clinical trials related to orthodontic retention for non-cleft and non-surgical cases.

Influence of fixed orthodontic steel retainers on gingival health and recessions of mandibular anterior teeth in an intact periodontium - a randomized, clinical controlled trial

OBJECTIVE

Aim of this randomized clinical controlled trial was to evaluate the influence of fixed orthodontic steel retainers on gingival health and recessions of mandibular anterior teeth.

MATERIALS AND METHODS

After end of the orthodontic treatment, patients were randomly assigned into the test (fixed steel retainer) or control group (modified removable vacuum-formed retainer). Periodontal parameters (periodontal probing depth: PPD; recession: REC; bleeding on probing: BOP) as well as plaque and gingival index were assessed on mandibular anterior teeth directly before attaching/handing over the retainer (baseline: BL), 6 and 12 months after orthodontic treatment.

RESULTS

37 patients (test: n = 15, mean age: 16.1±4.2 years; control: n = 17, mean age: 17.1±5.4 years) completed the study. REC and PPD failed to show significant pairwise differences. The number of patients showing gingival health in the area of the mandibular anterior teeth (test: BL n = 10, 6 months n = 9, 12 months n = 11; control: BL n = 10, 6 months n = 16, 12 months n = 15) revealed a significant difference for the intra-group comparison between BL and 6 months in the control group (p = 0.043). The inter-group comparisons failed to show significant differences.

CONCLUSION

Young orthodontically treated patients with fixed steel retainers show in 73.3% healthy gingival conditions after one year which are comparable to the control group (88.2%). Gingival recessions were in a clinically non-relevant range at any time of the examination.

CLINICAL TRIAL NUMBER

DRKS00016710.

Preclinical in vitro study of streptococcus mutans accumulation in three fixed retainer designs: Microbiological assay

The use of fixed retainers in the lower arch is frequent; however, its presence increases the accumulation of biofilm and dental calculus. The objective of this research was to evaluate, in vitro, the accumulation of Streptococcus mutans (S. mutans) in 3 designs of fixed retainers. Nine models were reproduced in heat-cured acrylic resin and divided into groups: straight retainer (SR), retainer with vertical strap (RVS), retainer with horizontal strap (RHS). The accumulation of S. mutans was assessed using the MTT assay (3-4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetrazolium bromide) and then measured using an automated reader. The RHS group showed less biofilm accumulation compared to the other groups (p<0.05). The distance between the tooth surface and the retainer showed a strong negative correlation with biofilm accumulation (rs=-0.79, p=0.00037). The RHS showed significantly less accumulation of S. mutans due to the distance between the retainer and the tooth surface. This research provides relevant data for a future randomized clinical trial.

A cross-sectional study into the reasons behind orthodontic re-treatment

OBJECTIVE

This study aims to identify the motivations behind orthodontic re-treatment in Saudi Arabia.

MATERIALS AND METHODS

This is a cross-sectional study performed through a patient questionnaire. The questionnaire elicited data on the respondents' socio-demographic data, type of previous orthodontic treatment, retention, satisfaction level, and reasons for undergoing orthodontic re-treatment.

RESULTS

Four hundred and nineteen responses were received during the study period from June to July 2022. The result showed a pre-dominant female predilection (83, 29%), with the majority belonging to the 21-25 age group (47.26%). Most participants had had one previous orthodontic treatment (77%), with an active treatment time of approximately 1-3 years (55.85%). There was no significant difference between the satisfaction of outcomes after the initial treatment and at the time of the survey. Most participants received retention appliances (69.45%) and were informed about the importance of appliances. The type of retention was mainly removable retainers (47.5%). Around one-third of the sample (31.98%) were interested in seeking orthodontic re-treatment, with self-motivation as the primary drive and improving the smile as the predominant reason.

CONCLUSION

The study's findings show that a large portion of the population is seeking orthodontic re-treatment, which must be considered. Self-motivation was a driving force rather than external motivation. The most common reason for seeking orthodontic re-treatment was to improve their smile and the increased esthetic demand.

Changes in the distribution of occlusal forces in the course of the orthodontic retention phase : A prospective cohort study

PURPOSE

Aim of the present study was to assess the relative distribution of occlusal forces after orthodontic treatment and during the first 3 months of the retention phase using a computerized occlusal analysis system (T-Scan, Tekscan Inc., Norwood, MA, USA).

MATERIALS AND METHODS

A total of 52 patients were included in this prospective cohort study and underwent analysis of occlusal forces on the level of tooth, jaw-half, and -quadrant during a 3-month period. Furthermore, differences between three retention protocols (group I: removable appliances in both jaws; group II: fixed 3-3 lingual retainers in both jaws; group III: removable appliance in the maxilla and fixed 3-3 lingual retainer in mandible) were assessed with Wilcoxon signed-rank tests at 5%.

RESULTS

Directly after debonding, measured forces distribution were similar to published references for untreated samples. In the following, no significant difference was found between retention protocols II and III with regard to the asymmetry of the anterior occlusal forces. Both groups maintained an asymmetric force distribution in the anterior segment during the study period. There was also no difference between groups II and III in the distribution of occlusal forces for the posterior segments. Both retention concepts kept the symmetrical distribution of occlusal forces stable over the observation period. The retention concept of group I demonstrated a symmetrical distribution of occlusal forces in the anterior segment after debonding and this remained stable during the 3‑month period. In the posterior segment, no improvement of the initially asymmetric masticatory force distribution could be observed.

CONCLUSIONS

All three studied retention protocols showed stability in retaining their original symmetrical or asymmetrical occlusal force distribution posteriorly/anteriorly during the 3‑month observation period. Therefore, an even distribution of occlusal forces should be the aim of the finishing phase, as no relative benefit of any single retention scheme in terms of post-debond improvement during the retention phase was seen.

Incisor irregularity and dental arch dimensions changes in subjects with different severity of anterior crowding: a 37-year follow-up

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.

Fixed and removable orthodontic retainers, effects on periodontal health compared: A systematic review

The aim of this systematic review is to analyze the properties of the different types of orthodontic retainers, identify their differences and define which type of device is most effective and less harmful to periodontal health.

Methods

A literature search was carried out by a reviewer by consulting PubMed, Lilacs, Embase, Medline full text, Scopus, Web of Science, Cochrane library, and Science Direct electronic databases for biomedical and health literature as well as the grey literature and setting up the search from December 2010 without any restriction about articles languages.

Results

The results showed that patients who wear retainers for a long period have significant differences in clinical parameters compared to patients without retainers. The type of retainer chosen also significantly influences the overall periodontal health of patients. Fixed retainers, both glass-fibre reinforced and steel wire retainers, proved to be the retainer type with the highest plaque and calculus accumulation values compared to removable retainers. In addition, among fixed retainers, glass-fibre reinforced retainers proved to be those that mostly promote the plaque and calculus accumulation in the application site.

Conclusion

Fixed retainers are the best devices to maintain the alignment of mandibular anterior teeth in the long term. Among these devices, stainless steel lingual retainers, plain or braided, should remain the first choice. Although they are also susceptible to periodontal complications, their effect on periodontal health can be considered statistically insignificant if compared to glass-fibre reinforced retainers which, showing worse periodontal complications, should not be used.

Orthodontic Retainers-A Critical Review

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

Orthodontic Retainers-A Critical Review

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

Comparison of the debonding force of metal, glass and polyethylene Fiber reinforced composite retainers: Mechanical and finite element analyses

OBJECTIVE

The studies evaluating the efficiency of fiber reinforce composite (FRC) retainers are few and contradictory. This study aimed to compare the debonding force of metal, glass FRC (GFRC) and polyethylene FRC (PFRC) retainers, assess the interactions between the materials and forces, and pattern of load distribution by finite element analysis (FEA).

MATERIALS AND METHODS

Forty-eight sound lower incisors were collected and randomly assigned to 3 groups (n=8; each sample included 2 teeth). Next, 15mm of the three retainers (multi-stranded metal wire, GFRC, and PFRC) were bonded to the lingual surface of the teeth and debonding force was measured by a universal testing machine. For FEA, 3D models were designed. The data related to geometrical models and material properties were transferred to ANSYS software. A 187-Newton load was applied to the incisal edge of the two centrals. Then different parameters were assessed. The three groups were compared by one-way Anova and Tukey's test. Type one error was considered to be 0.05.

RESULTS

The debonding force decreased in the order: Metal (143.71N)≥GFRC (108.29N)>PFRC (45.08N). The difference between metal retainer and GFRC was not significant. In contrast, PFRC group showed significantly lower debonding force compared to other groups (P<0.05). FEA showed stress peak value in metal-composite interface. Maximum total deformation was noted in central, followed by lateral and canine.

CONCLUSIONS

Glass-FRC can serve as an alternative to metal retainers as the difference in debonding force is not significant. However, the difficulty of repairing or replacing the Glass-FRC should be taken into account given the large number of failure in the interproximal dental area.

Antimicrobial Activity of Various Disinfectants to Clean Thermoplastic Polymeric Appliances in Orthodontics

There is a lack of research evidence on the risk–benefits of the various disinfectants in cleaning products and cleansing regimens. This systematic review compared the antimicrobial activity of various chemical disinfectants to disinfect the thermoplastic polymeric appliances in orthodontics. The study was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Cochrane Handbook of Systematic Reviews of Interventions. An electronic search was conducted on Pubmed, Google Scholar, Scopus, ScienceDirect, and Springer. Two authors independently investigated the risk of bias in duplication. A total of 225 articles were collected. After removing duplicates, 221 articles remained, and after filtering their titles and abstracts, 11 articles met eligibility qualifications remained. Finally, nine articles that met the criteria were selected. It showed that both over-the-counter orthodontic appliance cleaners and applied-chemical disinfectants were effective against bacteria. The duration and frequency of usage guidelines cannot be concluded.

Survival analysis of three types of maxillary and mandibular bonded orthodontic retainers: a retrospective cohort

BACKGROUND

Retention is an important aspect of orthodontic treatment. This study aimed to analyze the survival of three types of maxillary and mandibular bonded orthodontic retainers.

METHODS

This retrospective cohort study evaluated the records of 118 orthodontic patients (90 females, 28 males, mean age of 22.34 ± 6.44 years) retrieved from a private orthodontic office. Data regarding the retainer failure, dental caries, unwanted tooth movements, maximum pocket depth (PD), and bleeding on probing (BOP) recorded at the follow-up sessions were extracted from patient records. Three types of retainer wires namely Bond-A-Braid, Orthoflex, and Retainium were compared regarding the abovementioned parameters. Data were analyzed by ANOVA, Chi-square, Monte-Carlo Chi-square, and Kruskal Wallis tests, the log rank test, and the Cox regression model.

RESULTS

The frequency of retainer failure was not significantly different between males and females, different age groups, or different treatment durations (P > 0.05). Wire fracture was the most common failure type in both the maxilla and mandible. Also, the frequency of failure was not significantly different between the maxillary and mandibular retainers (P > 0.05). The frequency of failure, and survival of the three types of retainer wires were not significantly different during a 5-year period (P > 0.05).

CONCLUSIONS

The three types of orthodontic retainers had comparable survival rates. Their failure rate was not correlated with the age or gender of patients or the treatment duration.

Orthodontic Retention-Protocols and Materials-A Questionnaire Pilot Study among Polish Practitioners

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.

Capabilities of Digital Software for Creating a 3D Printed Retainer

INTRODUCTION: The retention phase of orthodontic treatment is an important phase to prevent teeth returning to their initial position. An innovative solution for creating a retainer is through 3D printing by digital design. AIM: The purpose of this article is to demonstrate the capabilities of digital software in the creation of stabilization splint, type retainer, and after orthodontic treatment. MATERIAL AND METHODS: An intraoral scan of an orthodontically treated patient (18 years) was performed. A Trios Color scanner (3Shape) was used. 3Shape Dental system design – splint studio was used for file processing and design creation. The method of 3D printing was applied to make the retainer. With this method, the objects are created layer by layer from melted material with different nature. It was made by Dental LT Clear Resin (a biocompatible material) with Formlabs Form 2 printer. RESULTS: Depending on the selected thickness of the retainer and the position of the lower jaw, the software generates different distances between the dentitions. The digital design allows a change of 0.1 mm, which is impossible with a classic laboratory protocol. The resulting printed retainer fully meets our expectations – tooth adaptation, patient comfort, and aesthetics. CONCLUSION: Digital software and design provide many opportunities for modern orthodontics.

The influence of 3x3 bonded retainer on anterior crowding relapse in mandibular incisor extraction cases

Objective:

To evaluate the 3x3 bonded retainer influence on the mandibular anterior crowding in cases treated with mandibular incisor extraction

Methods:

The sample comprised pretreatment, posttreatment and follow-up orthodontic records of 16 subjects (10 females and 6 males) with Class I malocclusion treated with extraction of a single mandibular incisor. The mean ages (± SD) at pretreatment, posttreatment and follow-up evaluation were 23.45 ± 9.14 years, 25.50 ± 8.95 years and 30.11 ± 8.59 years, respectively. The mean (± SD) treatment time and posttreatment evaluation time were 2.05 ± 0.45 years and 4.60 ± 1.85 years , respectively. Little irregularity index and interdental widths were evaluated using dental casts. The sample was divided into two subgroups, according to the presence of the 3x3 bonded retainer at follow-up.

Results:

The subgroup without 3x3 bonded retainer presented a greater relapse at the follow-up, when compared to 3x3 bonded retainer subgroup.

Conclusion:

There was a significant relapse in cases treated with mandibular incisor extraction at follow-up. The subgroup without 3x3 bonded retainer showed a significant relapse at the follow-up when compared to the retainer group.

Experimental EDX analysis of different periodontal splinting systems

Physiological/normal tooth mobility may be defined as the slight displacement of the clinical crown of a tooth, which is allowed by the resilience of an intact and healthy periodontium, under the application of a moderate force. The factors influencing the success and longevity of dental splinting are the type of material used for the splint, the type of composite resin, the number and location of the dental units included for splinting (maxillary or mandibular arch). In periodontology, the term 'splint' is defined as the joining of two or more teeth into a rigid unit through restorations or fixed or removable devices. The purpose of using periodontal splints for tooth immobilization is to provide a period of rest in the areas where the healing process has begun and to allow normal functioning there where the tissues alone would not be able to withstand occlusal forces. The aim of the present study was to evaluate comparatively, by means of energy dispersive electron spectrometry (EDX), the chemical composition in the case of in vitro samples that structurally reproduce direct periodontal immobilization systems using fiberglass strips and fluid composite resins. The differences in the chemical composition of the investigated materials can influence their physiochemical properties, but also their biological and toxicological reliability. Elements such as C, O, Al, Si and Ba were identified as common elements among the resins tested in the present study. The only difference in terms of the component elements was found in the case of the fluid composite Clearfil Majesty ES Flow, which, apart from the elements mentioned, also presented Co in its structure.

Effects of Hawley, Essix, and Vivera® retainers on salivary properties, oral hygiene, and Streptococcus mutans levels: A prospective clinical pilot study

Objectives:

The objectives of the study were to investigate the in vitro and in vivo effects of various removable orthodontic retainer materials on clinical and microbiological parameters, specifically on saliva characteristics, oral hygiene, and salivary levels of Streptococcus mutans (S. mutans).

Materials and Methods:

This study consists of two parts: An in vitro study and in vivo prospective clinical pilot study. The in vitro study measures surface roughness and S. mutans adhesion of three orthodontic retainer materials: Polymethylmethacrylate (PMMA) used in traditional Hawley removable retainers, polypropylene (PP), and polyurethane (PU) used in vacuum-formed retainers. In the clinical pilot study, 20 subjects, on completion of orthodontic treatment were randomized into three groups to receive PMMA, PP, or PU removable orthodontic retainers. They were compared with control subjects with no orthodontic treatment and retainers. Quantitative analysis of salivary S. mutans using real-time polymerase chain reaction was performed to screen for differences during retainer issue (T0) and 8–15 weeks later (T1). Salivary flow rate, pH, buffering capacity, and plaque scores were also recorded at these two periods for comparison.

Results:

PMMA had significantly greater surface roughness and S. mutans adhesion than PP and PU (P = 0.027). The PMMA group displayed significantly greater amounts of salivary S. mutans count when compared to the PP (0.001) and PU (P = 0.011) groups.

Conclusion:

PMMA retainers showed increased S. mutans adhesion and intra-oral colonization of S. mutans compared to PP and PU retainers. The results validate further clinical testing for a relationship between caries risk and type of retainer prescribed.

Is YouTube an adequate patient resource about orthodontic retention? A cross-sectional analysis of content and quality

INTRODUCTION

The study aimed to evaluate the content and quality of information offered by YouTube for patients seeking information related to orthodontic retainers.

METHODS

YouTube was searched using the keyword "orthodontic retainers" from Google Trends. From the first 120 results, 97 videos were selected to be analyzed. Videos were rated for quality by video information and quality index (VIQI) and the global quality scale (GQS). Videos were classified as low- and high-content groups using a 10-point score considering several retainer-related topics. Mann-Whitney U tests, chi-square tests, and Pearson correlation coefficients were used for statistical evaluations.

RESULTS

Most YouTube videos were uploaded by dentists/specialists (62.9%). We classified 12 videos as high content and 85 as low content. Instructions on the use of the orthodontic retainer was the most commonly covered topic (42.3%), followed by the effect on oral hygiene (38.1%), definition (37.1%), procedure of preparing orthodontic retainers (33.0%), and procedure of positioning (30.9%). A lower percentage of videos (6.2%) mentioned soft tissue irritation. The high-content video group had a significantly higher median value of GQS score and VIQI (P <0.001). The correlation between GQS and VIQI was strong (r = 0.698; P <0.01).

CONCLUSIONS

The content of YouTube videos for orthodontic retainers could not be considered as an adequate source of information for patients on orthodontic retainers. Most videos included instructions on the use of orthodontic retainers, but fewer videos mentioned the effect on speech performance and soft tissue irritations.

TAD's for the Derotation of 90° Rotated Maxillary Bicuspids

It is undeniable that the advent of extra-alveolar mini-implants for anchorage purposes has revolutionized the field of Orthodontics. This case report sheds light on an innovative anchorage plan using TADs, to carry out treatment for a 15-year-old female patient. The patient reported to the clinic with a chief complaint of rotated second premolars, crowding, and a deep bite. On examination, it was seen that the patient had a Class I skeletal pattern, Class II subdivision molar relationship, 90-degree maxillary second premolar rotations, crowding in both the arches, and a deep bite. In this case, the clinicians decided to use TADs for premolar derotation as it not only provides a pure rotational couple without any deleterious effects on the adjacent teeth but also helps shorten the overall treatment time. The total treatment time for this case was 10 months.

Orthodontic treatment pause during COVID-19 outbreak: Are we overlooking potential harms to our patients and their treatment outcomes?

Introduction:

The global outbreak of coronavirus disease 2019 (COVID-19) has led all dental governing bodies across the world to minimize or cancel routine/elective dental procedures and limit dental services to only acute emergency situations. Orthodontic treatment is a long-term treatment that necessitates several appointments. However, if patients are left unsupervised during this pandemic, serious harms might arise apart from acute orthodontic emergencies.

Objective:

In this article we highlight these harms and their negative impact on patients and the overall success of their treatment.

Conclusion:

We briefly presented actions needed to be undertaken by orthodontists to gradually allow for recalling patients according to the stage of their treatment to avoid any potential harms to the treatment outcome and avoid any subsequent medicolegal consequences.

Comparison of post-treatment changes with and without retention in adolescents treated for maxillary impacted canines-a randomized controlled trial

Objective

To evaluate whether retention is needed after orthodontic treatment of impacted maxillary canines.

Trial design

Two-arm parallel group single-centre randomized controlled trial.

Materials and methods

Sixty-three patients, 39 girls and 24 boys, were recruited to the study. The inclusion criteria were patients with at least one impacted or unerupted maxillary canine, and moderate irregularity of the maxillary six anterior teeth according to Little’s index (LI). After gaining informed consent from the patient and their custodians, the patients were randomized to one of two groups, i.e. to a non-retention group or a retention group. The randomization process was prepared and carried out by an independent person not involved in the trial and the randomization used blocks of 20 (10 + 10). Primary outcomes were changes in single contact point discrepancy, and LI measured on digitalized three-dimensional study casts 1-year post-treatment. The study casts were anonymized before assessment and the changes were blinded for the assessor. Data were evaluated on an intention-to-treat basis. Thus, all randomized patients were incorporated into the final analysis. In the non-retention group a 10-week interim period was used to detect patients who eventually have a relapse immediately after treatment. If so, the patient got the arch-wire reinserted. Most patients in the retention group received a vacuum-formed retainer and pretreatment spacing cases got a bonded retainer.

Results

Mean irregularity change was 0.4 mm in the retention and 1.3 mm in the non-retention group (P < 0.001). Maximum change was 2.5 mm in the retention and 3.2 mm in the non-retention group (P < 0.001). Most changes in the non-retention group occurred during the 10-week interim period. In the non-retention group, one patient developed contact point discrepancy of >2 mm during the interim period and was realigned.

Harms

One patient met the stopping guideline criteria. This patient had the arch wire reinserted for 2 months. After realignment, the patient received a retention appliance.

Limitations

The trial was a single-centre study and short-term changes were evaluated.

Conclusions

Changes between the retention and the non-retention group were statistically but not clinically significant. Since satisfactory clinical results 1-year post-treatment were found in the non-retention group, retention does not appear to be needed. The 10-week interim period was useful in detecting patients who might have a relapse immediately after treatment.

Trial registration

The trial was not registered.

Periodontal effects and survival rates of different mandibular retainers: comparison of bonding technique and wire thickness

OBJECTIVES

This non-randomized prospective cohort study aimed to compare the periodontal effects and success rates of mandibular canine-to-canine fixed retainers having different bonding techniques and wire thicknesses.

MATERIALS AND METHODS

Hundred patients requiring retention after orthodontic treatment were assigned to five study groups (n = 20 in each group, 61 females/39 males, median age range 16.5-18.0 years). Retention was provided by 0.0215"/direct, 0.0215"/indirect, 0.0175"/direct, 0.0175"/indirect bonded multistranded wires and removable Essix appliances. The primary and secondary outcomes were periodontal effects and success rates. The patients were examined in 1 week, 1 month, 3 months and 6 months follow-up appointments. Plaque index, gingival index, probing depth, marginal recession, bleeding on probing, failure rate per retainer wire and survival of retainer wires were analysed by Kruskal-Wallis H, Mann-Whitney U and chi-square tests.

RESULTS

Significant differences were observed between the fixed retainer (FR) and Essix (E) groups in gingival index scores at 1 month [mean FR: 1.13 (95% confidence interval (CI): 0.81-1.44), mean E: 0.40 (95% CI: 0.14-0.69), mean difference: 0.73, P < 0.01], 3 months [mean FR: 0.97/1.01 (95% CI: 0.65-1.30/0.72-1.30), mean E: 0.52 (95% CI: 0.25-0.82), mean differences: 0.45/0.49, P < 0.05], 6 months [mean FR: 0.94 (95% CI: 0.62-1.27), mean E: 0.35 (95% CI: 0.15-0.58), mean difference: 0.59, P < 0.05] and in bleeding on probing scores at 1 month [mean FR: 3.05 (95% CI: 2.12-3.98), mean E: 1.15 (95% CI: 0.42-1.88), mean difference: 1.90, P < 0.01]. The survival rates of retainer wires were 85 per cent for the 0.0215" direct/indirect and 90 per cent for the 0.0175" direct/indirect groups for the 6 months follow-up.

LIMITATIONS

Six months follow-up period, which demonstrates only short-term outcomes.

CONCLUSIONS

The periodontal outcomes or survival rates of mandibular fixed retainers were not affected by bonding technique or wire thickness, whereas gingival health improved with Essix retainers but not with fixed retainers.

"Clinical comparison of bond failure rate between two types of mandibular canine-canine bonded orthodontic retainers- a randomized clinical trial"

BACKGROUND

Bonded retainers are widely used as they are esthetically pleasing, easily acceptable, provide greater stability, compliance free and causes no soft tissue irritation and speech problems. Though, fracture and bond failure are their shortcomings. Therefore, the objectives of this study were to evaluate the number of bond failures and type of failure pattern between two types of mandibular canine-canine bonded retainers.

METHODS

Total 60 subjects were recruited initially and were assessed for eligibility, out of which 6 were excluded and 2 were lost to follow up. They were randomly divided into two groups. Fiber reinforced composite (FRC) retainers were inserted in group 1 subjects while group 2 subjects received multistranded stainless steel (MSW) retainers. The subjects were recalled after every 3 months over a period of 1 year. Bond failure rate and failure pattern based on adhesive remnant index were evaluated at each visit. The bond failure rate and failure pattern were compared between the two retainers by using Chi-square test.

RESULTS

The bond failure rates were 42.94% for FRC retainer and 31.41% for MSW retainer. Hence, total number of bond failures in both retainers were 37.17%. The difference of bond failure between two groups was statistically significant (p = 0.012). Type "0" failure pattern was detected commonly with both types of retainers (p <  0.001).

CONCLUSION

Our findings indicate that multistranded stainless steel wire retainer is a superior option to be used for fixed lingual retention in mandibular arch as it exhibited lower bond failure as compared to fiber reinforced composite retainer. Adhesive failure is the most common type of bond failure observed with both types of fixed retainers.

TRIAL REGISTRATION

ID NCT03881813 ( https://clinicaltrials.gov/ ); March 19, 2019, retrospective registration.

Occlusal contact area changes with different retention protocols: 1-year follow-up

INTRODUCTION

The purpose of this study was to evaluate the occlusal contact area and cast-radiograph evaluation (CRE) score changes in patients with 3 different retention protocols after a 1-year retention period.

METHODS

A total of 90 patients with acceptable final occlusion according to American Board of Orthodontics CRE were equally divided into 3 groups according to the retention protocol: upper bonded retainer and lower Essix or bonded retainer (Essix group); upper bonded retainer and Hawley or lower bonded retainer (Hawley group); and upper bonded retainer and lower bonded retainer (bonded retainer group). Digital models were used to assess occlusal contact area changes after a 1-year retention period. The follow-up occlusion models were assessed with the American Board of Orthodontics CRE.

RESULTS

Occlusal contact areas increased significantly in the Hawley and bonded retainer groups for all teeth except incisors. The bonded retainer group showed the greatest amount of settling, but differences with the Hawley group were not statistically significant. However, statistically significant decreases in occlusal contact areas were recorded for the Essix group except for incisors. A decrease of CRE scores was seen in the Hawley group, whereas a statistically significant increase was recorded in the Essix group.

CONCLUSIONS

Both Hawley and bonded retainers allowed settling of the occlusion during the retention phase, whereas the Essix retainer did not allow relative vertical movement of the posterior teeth. The Hawley group showed improvement in the total CRE score, whereas the Essix group showed worsening.

ORTHODONTIST CLINICAL EXPERIENCE AND CLINICAL SITUATION SIGNIFICANTLY INFLUENCE THE RETENTION PROTOCOL - A SURVEY FROM CROATIA

The aim was to assess the views and practice of Croatian orthodontists concerning retention protocols. A total of 150 questionnaire copies were distributed, of which 92 were validly completed. The survey included sociodemographic characteristics, practices of informing patients about retention options, commonly used appliances, and reasons for choosing a particular type of retention and treatment duration. Orthodontists informed patients about retention mostly verbally, the retention period was 3-5 years, the choice of method depended on the malocclusion (76%), and the protocol was influenced by clinical experience of the orthodontist (39%). The most commonly used appliance in the maxilla was the vacuum-formed retainer (52%), whereas a combination of fixed and removable retainers was most common in the mandible (34%). Modus of acquiring knowledge, biological reasons (malocclusion type, oral health, treatment outcome, and growth) and the patient’s wishes were not a predictor of retention duration or recall frequency. With an increase in orthodontic experience, the duration of retention decreased and orthodontists were more likely to change the duration of retention (p=0.001), as well as the type of retention appliance (p<0.001). In conclusion, retention protocols among Croatian orthodontists were influenced mostly by their clinical experience and clinical situation.

One-year rotational relapse frequency following conventional circumferential supracrestal fiberotomy

BACKGROUND

Relapse following orthodontic treatment has been a common problem that can occur due to several factors. It was suggested that surgical circumferential supracrestal fiberotomy (CSF) is an effective measure to reduce this relapse. However, very few studies have reported the amount of relapse that occurs afterward.

AIM

To assess the frequency of rotational relapse on anterior teeth 1 year following CSF.

METHODS

Eleven adults (six male and five female) with a mean age of 23 years (standard deviation = 5.2), who had a total of 90 rotated anterior teeth, were included in this study. CSF was performed after comprehensive orthodontic treatment involving the use of full-fixed preadjusted edgewise appliances (Victory Series APC, 3M, United States) with a 0.022-inch slot and Roth prescription brackets (Ovation; DENTSPLY GAC, Bohemia, New York, United States) and placement of a fixed lingual retainer from canine to canine in both arches using a 0.016 Australian wire (AJ Wilcock, Australia). Degrees of rotational correction and relapse were measured on three sets of casts [pretreatment, post-treatment (at the debond visit), and 1-year post-treatment]. Rotational relapse was categorized as follows: Unnoticeable relapse (0°), barely noticeable relapse (1°-3°), noticeable relapse (4°-9°), and clearly noticeable relapse (≥ 10°). The percent relapse that had occurred 1 year after teeth were aligned to their ideal position was calculated. Data were analyzed by dental arch type and tooth types.

RESULTS

Mean rotational correction was 14.05° during posttreatment. Mean relapse at 1-year follow-up was 1.1° (10.8%). More than half (n = 52, 57.8%) of teeth were categorized as having unnoticeable relapse (0°). Of the remaining teeth, 31 (34.5%) had barely noticeable relapse (1°-3°), 6 (6.6%) had noticeable relapse (4°-9°), and only one (1.1%) had clearly noticeable relapse (> 10°). When analyzed by arch, 54.5% (n = 6) of the relapsed maxillary teeth had barely noticeable relapse (1°-3°). While most of the mandibular teeth (3, 37.5%) fell into noticeable relapse category (4°-9°), only 1 (12.5%) tooth had clearly noticeable relapse (≥ 10°).

CONCLUSION

When relapse was measured following CSF, it was found to be more pronounced in maxillary than in mandibular arch. Most frequent relapse was found in maxillary lateral incisors and mandibular canines.

Level of satisfaction in the use of the wraparound Hawley and thermoplastic maxillary retainers

OBJECTIVE

To compare the level of satisfaction in the use of wraparound Hawley and thermoplastic maxillary retainers.

MATERIALS AND METHODS

The study sample included 70 orthodontic patients (24 males and 46 females), who were in the retention stage (mean age = 20.80 years). All patients wore the two types of maxillary retainer for 1 month each, along with a 3×3 fixed mandibular retainer. After the use of each retainer, the patients responded to a questionnaire evaluating the level of satisfaction with their use of the maxillary retainer. Intergroup comparison was performed by independent t tests. Chi-square test was used to evaluate preference for the type of retainer by gender.

RESULTS

The thermoplastic retainer was better for swallowing and the wraparound Hawley appliance was better for hygiene and durability. The other factors evaluated (adaptation, speech, comfort, esthetics, satisfaction, and fitting) did not show significant differences between the retainers. There was also no significant difference in preference for the appliances.

CONCLUSIONS

Regarding the overall satisfaction and the preference, there was no difference between the wraparound Hawley and thermoplastic retainers. The wraparound Hawley appliance was better in hygiene and resistance than the thermoplastic retainer; and the thermoplastic appliance was better than the wraparound Hawley for swallowing fluids and saliva.

Rotational relapse of anterior teeth following orthodontic treatment and circumferential supracrestal fiberotomy

Background/purpose

Several factors cause relapse of orthodontically de-rotated teeth after appliance removal. Circumferential supracrestal fiberotomy (CSF) may release the tension on the supra-alveolar fibers following tooth de-rotation, thereby reducing the relapse risk. However, careful identification of the amount and location of relapse enables proper clinical evaluation. We aimed to determine the amount of orthodontic relapse following CSF for de-rotated anterior teeth.

Materials and methods

Eleven patients with 90 orthodontically de-rotated anterior teeth were enrolled. CSF was performed after orthodontic treatment, during fixed retainer placement. Rotational correction and relapse were measured on three casts (preorthodontic treatment, cast 1; postorthodontic treatment + CSF, cast 2; and 12-month follow-up, cast 3). The Wilcoxon test was used to assess significant differences in the tooth rotation angles between casts 1 and 2 and casts 2 and 3. The relationship between the magnitude of relapse and pretreatment severity of rotation was assessed by the point biserial correlation test. The Mann-Whitney U test helped in identifying significant differences in the amount of relapse between maxillary and mandibular teeth.

Results

The mean amount of rotational correction was 14.05°, while the mean amount and percentage of relapse were 1.1° and 10.8%, respectively [0.81° (8%) and 1.44° (14%) for maxillary and mandibular teeth, respectively]. The relapse amount was proportional to the pretreatment rotation severity, and it was larger for the mandibular canines. There was no significant difference in the amount of relapse between the maxillary and mandibular teeth (P = 0.07).

Conclusion

Post-treatment rotational relapse of anterior teeth subjected to CSF was minimal and statistically insignificant after 1 year of follow-up. This validates the promising results of CSF when combined with appropriate mechanical retention for an adequate period.

Systematic reviews in orthodontics: Impact of the PRISMA for Abstracts checklist on completeness of reporting

INTRODUCTION

This study evaluated and compared the completeness of reporting of abstracts of orthodontics systematic reviews before and after the publication of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Abstracts Checklist (PRISMA-A).

METHODS

Abstracts of systematic reviews and meta-analyses in orthodontics published in PubMed, Latin American and Caribbean Health Sciences Literature, and the Cochrane Database of Systematic Reviews databases before March 23, 2018, that met the predefined inclusion and exclusion criteria, were evaluated using the 12 items of PRISMA-A, scoring each item from 0 to 2. Abstracts were classified into 2 groups: before and after publication of the PRISMA-A checklist. Three calibrated evaluators (intraclass correlation coefficient and kappa > 0.8) assessed the scores for compliance with the checklist. The number of authors, country of affiliation of the first author, performance of meta-analysis, and topic of the article were recorded. A regression analysis was performed to assess the associations between abstract characteristics and the PRISMA-A scores.

RESULTS

Of 1034 abstracts evaluated, 389 were included in the analysis. The mean PRISMA-A score was 53.39 (95% CI, 51.83-54.96). The overall score for studies published after the publication of the checklist was significantly higher than for studies published before (P ≤ 0.0001). The components returning significantly higher scores after publication of PRISMA-A were title (P = 0.024), information from databases (P = 0.026), risk of bias (P ≤ 0.0001), included studies (P ≤ 0.0001), synthesis of results (P ≤ 0.0001), interpretation of results (P = 0.035), financing and conflict of interest (P ≤ 0.0001), and registration (P ≤ 0.0001). These results showed the positive effect of PRISMA-A had on the quality of reporting of orthodontics systematic reviews. Nevertheless, the poor adherence revealed that there is still need for improvement in the quality of abstract reporting.

CONCLUSIONS

The quality of reporting of abstracts of orthodontic systematic reviews and meta-analyses increased after the introduction of PRISMA-A.

Which factors influence orthodontists in their decision to extract? A questionnaire survey

Background

To evaluate the relative influence of different criteria in the choice between extraction and nonextraction treatment in current orthodontics, and to assess how the percentage of extractions has evolved over time.

Material and Methods

Pre-treatment records (panoramic radiograph, lateral cephalogram, study casts and photographs) of fourteen cases in permanent dentition (adult or adolescent) with class I molar relationship and moderate anterior crowding were evaluated by 28 orthodontists. For each case, each orthodontist filled out a questionnaire reporting his treatment plan proposal (extraction or nonextraction) and the importance of specific parameters in his decision-making process, using categorical scales. Orthodontists practicing for more than 15 years were also asked to compare this decision with the one they would have taken at the beginning of their professional career.

Results

The two most important factors in the decision-making were the soft tissue profile and the amount of crowding. The least important factor was the presence of third molars. In cases of nonextraction treatment, the lack of space was managed mostly by dental expansion and stripping. Twenty percent of the case evaluations revealed extraction(s) decisions. Among the orthodontists practicing for more than 15 years, the current extraction rate reached 24%, whereas the same orthodontists reported they would have extracted in 39% of the cases in the past.

Conclusions

The present study suggests that soft tissue profile has a higher impact than traditional criteria such as cephalometric measurements in the extraction decision. This is associated with a decreased extractions rate compared to the past.

Key words:Orthodontics, extractions, survey, treatment planning.

Comparison of conventional and laser-aided fiberotomy in relapse tendency of rotated tooth: A randomized controlled clinical trial

INTRODUCTION

The aim of the present study was to compare the tendency of mandibular incisor rotation relapse after conventional circumferential supracrestal fiberotomy (CSF) with Er,Cr:YSGG laser-aided CSF.

METHODS

In this three-arm parallel study, the patients with one lower incisor rotation greater than 30 degrees before treatment were selected. The patients were randomly assigned to three groups in a 1:1:1 ratio. Rotational relapse tendency was measured on a digitized model one month after arch wire removal. Probing depth, clinical crown height and pain levels were also measured.

RESULTS

A total of 46 patients were recruited. Relapse tendency in conventional CSF and laser-aided CSF groups were 5.09±1.59° and 4.87±2.08°, respectively, and significantly lower than 11.28±2.93° in the control group (P<0.001). Relapse tendency was not different between the conventional CSF and laser CSF groups. Probing depth, clinical crown height, and experienced pain levels exhibited negligible differences.

CONCLUSIONS

Er,Cr:YSGG laser-aided CSF in one month was as effective in reducing rotational relapse tendency of mandibular incisor teeth as conventional CSF.

Long-term effects of various cleaning methods on polypropylene/ethylene copolymer retainer material

OBJECTIVES

To evaluate long-term light transmittance, surface roughness, and flexural modulus of polypropylene/ethylene copolymer retainer material after exposure to different cleaning methods.

MATERIALS AND METHODS

Standardized polypropylene/ethylene copolymer retainer specimens (n = 70, 50.8 mm × 12.7 mm × 1.0 mm) were subjected to seven chemical cleaning solutions: Invisalign cleaning crystals, Retainer Brite, Polident, Listerine mouthwash, 2.5% acetic acid, 0.6% NaClO, and 3% H₂O₂ for 6 months. The specimens were exposed to the different solutions twice a week for 15 minutes or according to manufacturer's instructions, then stored in artificial saliva at 37°C. Another group of specimens (n = 10) were brushed with a standardized toothbrushing machine for 2 minutes twice a week. At baseline and 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified using spectrophotometry, profilometry and three-point bend testing, respectively. Qualitative analysis was performed using a scanning electron microscope (SEM). Statistical analyses were performed at a significance level of .05.

RESULTS

The results showed that light transmittance decreased significantly from baseline for all cleaning methods at 6 months. For an individual method, no significant differences were observed between specimens at baseline and 6 months in surface roughness and flexural modulus. No discernible differences in surface features were observed on SEM images.

CONCLUSIONS

The results indicate that different cleaning methods affect the long-term light transmittance of the studied polypropylene/ethylene copolymer retainer material. However, for an individual cleaning method, no significant differences were shown for surface roughness or flexural modulus values at 6-months compared to baseline.

Gingival condition associated with two types of orthodontic fixed retainers: a meta-analysis

Background

The maintenance of gingival health around orthodontic fixed retainers (FRs) is difficult and different designs have been proposed.

Objective

The goal of this systematic review was to analyse whether FR designs that allow unobstructed interproximal flossing, compared with the ones that do not, improve gingival parameters.

Search methods

Detailed individual database search strategies for Cochrane Library, 'Latin' American and 'Caribbean' Health Sciences Literature, PubMed, Scopus, and Web of Science were developed. Grey literature was also considered.

Selection criteria

Clinical trials and cross-sectional studies that compared two types of FRs (plain and waved) were included and evaluated.

Data collection and analysis

Study selection, data extraction, and risk of bias (RoB) assessment were performed individually and in duplicate. The methodology quality was assessed using the MAStARI RoB tool.

Results

Four studies met the inclusion criteria, and all presented moderate RoB. While two of those studies found a statistically significant difference in gingival parameters, the other two did not report differences. A meta-analysis was conducted based on two of the selected studies, which performed evaluations of plaque index (PI) and calculus index (CI). The results revealed no differences on PI between wave FR and plain FR of 0.46 (0.24 to 0.69) and no differences on CI of 0.12 (-0.10 to 0.33). Regarding comfort, no clear differences were identified.

Conclusions

There is not enough scientific evidence to support or not an association between FR design and gingival health, flossing frequency, or patient comfort.

Registration

PROSPERO - CRD42016030059.

Clear retainer

A clear retainer is a removable retainer that is popular in the present day. Compared with conventional fixed and removable orthodontic retainers, it is a more esthetic, comfortable, and inexpensive appliance. Although several studies have been published about clear retainers, it could be difficult to interpret the results because of the variety of study designs, sample sizes, and research methods. This article is intended to compile the content from previous studies and discuss advantages, disadvantages, fabrication, insertion, and adjustment. Moreover, the effectiveness in maintaining dental position, occlusion, retention protocols, thickness, and survival rate of clear retainers is discussed.

Correlation between parodontal indexes and orthodontic retainers: prospective study in a group of 16 patients

PURPOSE

Fixed retainers are used to stabilize dental elements after orthodontic treatment. Being it a permanent treatment, it is necessary to instruct patients about a constant and continuous monitoring of their periodontal conditions and a correct oral hygiene. The aim of this study was to highlight the possible adverse effects of bonded retainers on parameters correlated to the health conditions of periodontal tissues.

MATERIALS AND METHODS

We selected 16 patients, under treatment in the Orthodontics Department of University of Bari Dental School, who had undergone a lingual retainer insertion at the end of the orthodontic treatment. The patients were then divided into two groups (Control Group and Study Group) and monitored for 3 and 36 months, respectively. The following indexes were taken into consideration: gingival index (GI), plaque index (PI) and the presence of calculus (Calculus Index, CI), the probing depth and the presence of gingival recession on the six inferior frontal dental elements.

RESULTS

After the observation was carried out, any of the patients showed periodontal sockets and gingival recession. In the Study Group, only 1 patient had a PI score=3, the 7 left had scores between 0.66 and 2.83. In the Control Group, one patient had score=0, the other ones showed values between 0.5 and 1.66. The mean GI in the Study Group peaked at a score of 2.83, the minimum was 0.66; whereas in the Control Group the maximum value was 2 and the minimum 0.66. The CI in the Group Study was between 1 and 2. In the Control Group it was absent in only 1 patient, whereas in the remaining 7, it had a value between 0.3 and 1. The clinical data were studied by means of the Wilcoxon test. We found a statistically significant difference for what concerns the Plaque Indexes (PI) (P>0.05) and Calculus Indexes (CI) (P>0.1) in both groups, with higher scores in the Study Group, having retainers for 36 months. Any statistically significant difference was calculated for the GI.

CONCLUSIONS

We can therefore conclude that patients with lingual retainers need periodontal hygiene and treatment as to prevent, in the course of time, periodontal damages non-detectable in short-term.

A multicentre audit of GDPs knowledge of orthodontic retention

OBJECTIVE

To determine GDP knowledge and willingness to supervise orthodontic retention and provide replacements retainers.

DESIGN

An audit sampling GDPs from six centres within England (Bradford, Cambridge, Burton-Upon-Trent, Croyden, Norwich and Plymouth). A gold standard of 100% of GDPs should be aware of commonly used retainers and be able to provide replacements was selected.

METHOD

Overall, 1,053 postal questionnaires were sent to local GDPs. The questions covered knowledge and provision of various retainers, practitioner background and education. GDP satisfaction with the information provided by the orthodontist at discharge was also explored.

RESULTS

Five hundred and two questionnaires were received (response rate of 48%). The majority of GDPs (64%) were trained in the UK. Awareness of vacuum-formed, Hawley and fixed retainers was generally high. A significantly smaller number of GDPs were willing to prescribe, fit or review the retainers. The most common reasons for reluctance in provision were insufficient knowledge, financial and time constraints. Over two thirds (72%) of GDPs would like further training on retention.

CONCLUSION

This audit highlights a need for increased training at undergraduate and postgraduate levels to update practitioners about contemporary retention practice. Better communication is required from orthodontists to GDPs to ensure that on discharge the dentist is aware of the retainer type and retention regime.

Retention in orthodontics

Retention is necessary following orthodontic treatment to prevent relapse of the final occlusal outcome. Relapse can occur as a result of forces from the periodontal fibres around the teeth which tend to pull the teeth back towards their pre-treatment positions, and also from deflecting occlusal contacts if the final occlusion is less than ideal. Age changes, in the form of ongoing dentofacial growth, as well as changes in the surrounding soft tissues, can also affect the stability of the orthodontic outcome. It is therefore essential that orthodontists, patients and their general dental practitioners understand the importance of wearing retainers after orthodontic treatment. This article will update the reader on the different types of removable and fixed retainers, including their indications, duration of wear, and how they should be managed in order to minimise any unwanted effects on oral health and orthodontic outcomes. The key roles that the general dental practitioner can play in supporting their patients wearing orthodontic retainers are also emphasised.

The effects of fixed and removable orthodontic retainers: a systematic review

OBJECTIVE

In the view of the widespread acceptance of indefinite retention, it is important to determine the effects of fixed and removable orthodontic retainers on periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes.

METHODS

A comprehensive literature search was undertaken based on a defined electronic and gray literature search strategy (

PROSPERO

CRD42015029169). The following databases were searched (up to October 2015); MEDLINE via OVID, PubMed, the Cochrane Central Register of Controlled Trials, LILACS, BBO, ClinicalTrials.gov, the National Research Register, and ProQuest Dissertation and Thesis database. Randomized and non-randomized controlled clinical trials, prospective cohort studies, and case series (minimum sample size of 20) with minimum follow-up periods of 6 months reporting periodontal health, survival and failure rates of retainers, cost-effectiveness, and impact of orthodontic retainers on patient-reported outcomes were identified. The Cochrane Collaboration's Risk of Bias tool and Newcastle-Ottawa Scale were used to assess the quality of included trials.

RESULTS

Twenty-four studies were identified, 18 randomized controlled trials and 6 prospective cohort studies. Of these, only 16 were deemed to be of high quality. Meta-analysis was unfeasible due to considerable clinical heterogeneity and variations in outcome measures. The mean failure risk for mandibular stainless steel fixed retainers bonded from canine to canine was 0.29 (95 % confidence interval [CI] 0.26, 0.33) and for those bonded to canines only was 0.25 (95 % CI: 0.16, 0.33). A meta-regression suggested that failure of fixed stainless steel mandibular retainers was not directly related to the period elapsed since placement (P = 0.938).

CONCLUSION

Further well-designed prospective studies are needed to elucidate the benefits and potential harms associated with orthodontic retainers.

Evaluation of the effects of subgingival injection of Simvastatin on space re-opening after orthodontic space closure in adults

Background. This clinical trial evaluated the effect of Simvastatin on space re-opening after orthodontic space closure and its effect on the gingival index (GI) and clinical attachment loss (CAL). Methods. 16 females, 25-40 years old, with spaces between anterior mandibular teeth due to chronic periodontitis were participated in this study. The patients were randomly divided into control and experimental groups. In the experimental group, 1.2% Simvastatin gel and in the control group, 0.9% sodium chloride as a placebo was injected into the pocket depth of the six anterior teeth. The amount of space reopening, GI and CAL were measured. Results. No serious complications were observed during interventions and follow-up periods. Space re-opening was significantly reduced in patients receiving Simvastatin (P < 0.001). Moreover, GI reduction was significantly greater in Sim-vastatin group compared to the control group (P < 0.001). However, CAL did not demonstrate a significant difference between the groups. Conclusion. Simvastatin may decrease space re-opening after orthodontic space closure in human anterior teeth.

Antimicrobial activity of a quaternary ammonium methacryloxy silicate-containing acrylic resin: a randomised clinical trial

Quaternary ammonium methacryloxy silicate (QAMS)-containing acrylic resin demonstrated contact-killing antimicrobial ability in vitro after three months of water storage. The objective of the present double-blind randomised clinical trial was to determine the in vivo antimicrobial efficacy of QAMS-containing orthodontic acrylic by using custom-made removable retainers that were worn intraorally by 32 human subjects to create 48-hour multi-species plaque biofilms, using a split-mouth study design. Two control QAMS-free acrylic disks were inserted into the wells on one side of an orthodontic retainer, and two experimental QAMS-containing acrylic disks were inserted into the wells on the other side of the same retainer. After 48 hours, the disks were retrieved and examined for microbial vitality using confocal laser scanning microscopy. No harm to the oral mucosa or systemic health occurred. In the absence of carry-across effect and allocation bias (disks inserted in the left or right side of retainer), significant difference was identified between the percentage kill in the biovolume of QAMS-free control disks (3.73 ± 2.11%) and QAMS-containing experimental disks (33.94 ± 23.88%) retrieved from the subjects (P ≤ 0.001). The results validated that the QAMS-containing acrylic exhibits favourable antimicrobial activity against plaque biofilms in vivo. The QAMS-containing acrylic may also be used for fabricating removable acrylic dentures.