Orthodontic retention experience of university students: A qualitative study.

OBJECTIVE: To explore university students' experience of retention and identify potential barriers and facilitators to long-term adherence. DESIGN: Cross-sectional qualitative study using virtual focus groups. SETTING: University of Leeds. PARTICIPANTS: Dental and non-dental students from the University of Leeds, who had previously undergone orthodontic treatment and had received removable retainers. METHODS: Students were invited to participate via email. Virtual focus groups were undertaken using Microsoft Teams. A topic guide was used to explore the experience of orthodontic retention including factors that influence long-term retainer wear. Focus groups were recorded and analysed using an inductive thematic approach. RESULTS: In total, 23 students participated in four focus groups, including 13 dental students. The period since the end of orthodontic treatment varied from 9 months to 10 years. Of the 23 participants, 8 (35%) were no longer wearing their retainers. Four themes were identified: (1) experience of orthodontic treatment including knowledge of relapse; (2) experience of retainer wear, including motivators and barriers; (3) role of others; and (4) increasing adherence. Key factors influencing use of retainers were the importance placed on maintaining treatment outcomes, awareness of unwanted tooth movement and understanding of the role of the retainer, access to replacement retainers, and ongoing support to encourage retainer wear. Greater knowledge and dental awareness reported by dental students did not necessarily increase adherence. CONCLUSION: Adherence to removable retainer wear is an important aspect of orthodontic treatment but it is recognised that long-term retainer wear is highly variable. The understanding of relapse and retention is variable. Challenges in gaining access to replacement retainers are a common cause of cessation of retainer wear. Dental professionals are perceived to be important in encouraging and supporting retainer wear and individuals reported they would like more follow-up.

External Root Resorption of Second Molars Due to Impacted Mandibular Third Molars during Orthodontic Retention.

Whether there is a relationship between impaction of the third molars and the onset of crowding remains to be determined, and extraction of third molars after orthodontic treatment is left to the judgement of the practitioner. This report describes a case where a third molar caused external root resorption (ERR) of the mandibular second molar after orthodontic treatment. As ERR of the mandibular second molar was detected after non-extraction orthodontic treatment, the affected tooth was extracted and substituted with the third molar. External root resorption of the second molar occurred despite being determined as low risk given the state of the impacted third molar as observed on a panoramic radiograph obtained at the end of active treatment. The present results indicate that in cases where the mandibular third molar is present, the corpus length is short, and non-extraction treatment has been performed, it is necessary to obtain X-ray images on a regular basis or preventively extract the third molar to avoid ERR of the second molars.

[The quality of life of patients after orthodontic treatment depending on the use of different types of retention appliances]. / Kachestvo zhizni patsientov posle ortodonticheskogo lecheniya v zavisimosti ot ispol'zovaniya razlichnykh vidov retentsionnykh apparatov.

AIM: To assess the impact of the type of retention device on the quality of life of orthodontic patients. MATERIAL AND METHODS: 311 patients were divided into four groups according to age. At the end of active orthodontic treatment, retainers were installed. After 6 months, a questionnaire was conducted using the standard OHIP-14 questionnaire in order to identify the attitude to the equipment used, the presence or absence of relapses and satisfaction with the state of the dental system. RESULTS: The number of relapses in all groups is approximately at the same level, which indicates almost equal opportunities for retainers to retain the achieved result. There is no correlation between the convenience of using a particular type of retainer and the willingness to do so. CONCLUSION: The motivation of patients to use removable or non-removable retention devices to a certain extent depends not only on the type of retainer, but also on the age at which the treatment was performed.

Periodontal status in long-term orthodontic retention patients up to 10 years after treatment - a cross-sectional study.

OBJECTIVE: To assess periodontal status in long-term orthodontic retention patients and investigate possible risk indicators. MATERIALS AND METHODS: Plaque index (PI), gingival index (GI), probing pocket depth (PPD), gingival recessions (GR) and calculus were recorded in 211 patients with or without fixed retainers. RESULTS: Periodontal parameters were within the limits of clinically healthy periodontium. The use of fixed retainers was associated with higher PI in the maxilla (ß = 1.10 [0.37]; p <.05). Older age was associated with higher PI in the mandible (ß = 0.27 [0.11]; p <.05). Smoking was associated with gingival bleeding on both palatal (ß = 0.63 [0.16]; p < .01) and labial sides in the maxilla (ß = 0.46 [0.20]; p <.05). Smoking was also associated with increased prevalence of GR in the mandible (ß = 0.24 [0.07]; p <.01), while use of snuff had similar effect on the labial side in the maxilla (ß = 0.35 [0.08]; p <.01). Higher age (ß = 0.05 [0.02]; p <.05) and the presence of a retainer (ß = 0.23 [0.07]; p < .05) were associated with calculus accumulation on the lingual side in the mandible. CONCLUSION: The present observational study suggest that long-term fixed retainers alone have no detrimental effect on the periodontium. Additional factors may increase the risk of plaque deposits and increased probing pocket depths. Further prosepective studies are needed to confirm the present outcome.

Influence of olive oil on alveolar bone response during orthodontic retention period: rabbit model study.

OBJECTIVES: This study attempted to evaluate clinically and histologically the effects of olive oil (Ol) consumption on orthodontic relapse after the retention period. DESIGN: Thirty apparently healthy female albino rabbits, weight more than 1000 g each was used in this study. The animals were grouped randomly into six groups of five animals each: two control and four experimental groups. In control groups, the relapse was estimated either at zero day, or at the end of the fourth week after orthodontic retention period. In the experimental groups, the animals' groups received Ol, 7.7, or 15.4 ml/kg b.w. per day during the orthodontic retention period. The relapse was estimated either at zero day, or at the end of the fourth week after orthodontic retention period for each concentration. Modified fixed orthodontic appliances were attached to the rabbits' lower central incisors. Each rabbit received orthodontic intervention for one week, followed by six weeks retention period. At the end of the experiments, the clinical and histological investigations were conducted. Data analyses were performed at the level of p < .05 for the statistically significant difference. RESULTS: Clinically, Ol high concentration four weeks group showed a significantly lower relapse tendency than control four weeks group. Histologically, Ol low concentration zero time group showed significantly higher osteoblasts numbers than control zero time group. Olive oil low and high concentrations four weeks group showed significantly lower fibroblasts count. Moreover, Ol high concentration four weeks group revealed significantly higher bone mineralization, osteoblasts and osteocytes counts than control four weeks study group. CONCLUSIONS: Supplementation with Ol during an orthodontic retention period, especially at 15.4 ml/kg b.w. per day concentration, clinically reduced orthodontic relapse on rabbit model. Histologically, Ol increased osteoblasts and osteocytes counts and the relative amount of bone mineralization of connective tissue layer forming alveolar bone (AB) at the end of four weeks after the orthodontic retention period.

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.

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

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

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

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

Management Strategies for Open Bite Relapse: A Systematic Review and Meta-Analysis.

The purpose of orthodontic therapy is to correct malocclusion and produce a stable outcome that endures over time. Long-term stability can be difficult to achieve, and many patients relapse after treatment, particularly in instances of open bite relapse (OBR). This systematic review aimed to analyze different types of management strategies for OBR and conduct a meta-analysis to find the best method of dealing with relapse. A comprehensive search was carried out across six major online databases using relevant keywords pertaining to our study, including "open bite relapse," "orthodontic retention," "orthodontic surgery," "orthodontic appliance," "orthodontic management," "orthodontic treatment," "orofacial myofunctional therapy (OMT)," "skeletal anchorage," and "treatment follow-up period." Eleven studies were selected after the application of relevant inclusion and exclusion strategies. The mean follow-up period of treatment for the studies ranged from six months to 4.5 years. Of all the management strategies assessed, OMT was found to be the least effective for OBR management. Surgical management modalities, such as mandibular repositioning and molar intrusion using skeletal anchorage, in conjunction with the usage of orthodontic appliances, were found to be noticeably effective, especially in the cases of participants who were <18 years of age. However, when utilized on a singular basis, either of them was found to be lacking the desired effect. The overall odds ratio (OR) of 0.48 (0.37, 0.64) and risk ratio (RR) of 0.62 (0.51, 0.74) were obtained after the meta-analysis of the different interventions for OBR, indicating statistical significance. There were only 11 studies included in the study, so it's possible that not all management strategies for OBR were fully understood. The limited number of studies may also have affected the generalizability of the findings. Although statistical differences were obtained to a certain degree, more clinical trials are needed to assess the effect of such surgical modalities as a viable management tool for OBR, since these represent a significant limiting factor in terms of the overall cost of the treatment placed upon the patient. Prior to the start of the research, registration was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. The research protocol was created to meet the goals and was properly filed with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023401991).

Retention protocols and use of vacuum-formed retainers among specialist orthodontists.

OBJECTIVE: To evaluate retention protocols and use of vacuum-formed retainers (VFRs) among specialist orthodontists. DESIGN: Postal/electronic (e-) questionnaire. SETTING: Republic of Ireland. PARTICIPANTS: Members of the Dental Council of Ireland Specialist Register of Orthodontists and/or Orthodontic Society of Ireland. METHODS: A pilot-tested questionnaire was distributed to 123 eligible specialist orthodontists. Questions addressed respondent demographics, preferred retainer choice in the maxillary and mandibular arches, prescribed wear protocols, VFR characteristics and factors influencing retainer choice. Statistical analyses were performed using PASW® version 18. RESULTS: The response rate was 82%. VFRs were the most commonly chosen retainer, prescribed by 53% of respondents in the maxilla and 33% in the mandible. Full-time followed by part-time wear of removable retainers (RRs) was the wear protocol favoured by the majority (70-76%). Full occlusal coverage was the VFR design favoured by 93%. VFR sheet thicknesses of 1.0 mm (68%) and 0.75 mm (16%) were most commonly prescribed. Seventeen per cent were aware that their patients used their VFRs as a receptacle for dental bleaching gel. Life-time wear of retainers was advised by 67-78%. The operator factor that most influenced retainer choice was the pre-treatment situation (88%). CONCLUSIONS: VFRs were the most common retainer choice in the maxilla and mandible with full-time wear followed by part-time wear of RRs favoured by most. Full occlusal coverage with a thickness of 1.0 mm was the VFR design prescribed by the majority. More than one in six specialist orthodontists were aware that their patients used their VFRs as a receptacle for dental bleaching gel.

Evaluation of orthodontic retention and retainer content on the Reddit social media website.

BACKGROUND: Social media can provide insight into patient experiences with health care. The aim of this study was to evaluate the content regarding orthodontic retention and retainers on the social media website, Reddit. METHODS: A systematic search for relevant content submitted over a 12-month period on the Reddit forum, r/braces, was conducted. Qualitative analysis of the initial posts for themes and subthemes was conducted by two investigators. Responding comments to the initial posts were assessed for supportiveness for each initial poster and alignment with the evidence-base. Quantitative assessment was via descriptive statistics. RESULTS: A total of 271 initial posts and 984 comments satisfied the inclusion/exclusion criteria. All initial posts were by patients. Just 1.12% (n = 11) of the comments appeared to be provided by oral health professionals. Most initial posts were negative (50.18%; n = 136), and most comments were positive (70.42%; n = 693). Alignment with the evidence-base was high among the comments (67.89%; n = 668). Eight main themes were identified with concerns regarding the negative impact of retention and retainers on quality of life, compliance with retention protocols and relapse commonly expressed. Concern regarding fear of relapse when waiting for the initial or renewal of retainers was a novel finding. More negative sentiments about orthodontists were expressed than positive. CONCLUSIONS: Reddit is a supportive and reliable environment for patients regarding orthodontic retention and retainers. The content evaluation suggested deficiencies in communication processes between clinicians and patients. Greater engagement of the orthodontic profession in the provision of supportive and evidence-based information on an individual patient basis and through appropriate information channels is required.

Success of orthodontic treatment of linguoverted mandibular canine teeth using a direct inclined plane appliance.

This study evaluated the success rate of orthodontic treatment of linguoverted mandibular canines in dogs using a directly applied inclined plane device. Medical records were retrospectively evaluated at 11 veterinary dental specialty hospitals from 1999 to 2021. Malocclusion classes included 41.7% in class 1, 47.2% in class 2, 6.9% in class 3, and 4.2% in class 4. The severity of linguoversion was mild in 7.6% of teeth, moderate in 33.9%, and severe in 58.5%. There was complete resolution of linguoversion in 71.2% of teeth, functional resolution in 25.4%, and failure in 3.4%. The median treatment time was 42 (11-174) days. Adjuvant orthodontic treatments were performed at the same time as the inclined plane in 45.7% of teeth, including active force orthodontics, extractions of non-strategic teeth, gingivectomy, and odontoplasty. While the inclined plane was in place, 31.4% of dogs required an anesthetized appliance adjustment, and at the time of appliance removal, complications occurred in 19.4% of dogs. Of the teeth that had initial resolution, 14.4% had rebound movement that required additional treatment. This study supports the idea that an acrylic inclined plane is a good treatment option for linguoverted mandibular canines, with a 96.6% success rate within a median of 6 weeks. Yet, orthodontic retention may be necessary in these cases to avoid the need for additional therapies.

Analysis of the information contained within TikTok videos regarding orthodontic retention.

BACKGROUND: To analyze the content, reliability, and quality of relevant TikTok videos regarding orthodontic retention. METHODS: Six relevant terms were searched on the TikTok social media Web site. Uploaded videos satisfying inclusion/exclusion criteria were assessed for the presence of nine predetermined content domains and categorized as "high-content" (≥5) or "low-content" (<5). Reliability was determined using the DISCERN instrument and quality by the Global Quality Score (GQS). Layperson videos were evaluated for themes using discourse analysis. Intraclass coefficients for content, DISCERN scores, and GQS were calculated for intrarater reliability. Statistical analysis was via IBM SPSS Statistics (version 27.0.0.0; SPSS Inc. Chicago, IL). RESULTS: Orthodontists uploaded 37.8% and laypersons 34% of the 209 assessed videos. Just 22.1% of videos were considered to be 'high-content.' Quality of life issues related to retainer wear was the domain that was present least often in the videos provided by orthodontists (13.9%) and most often in those uploaded by laypersons (53.5%). High-content videos recorded greater mean GQS and DISCERN scores compared with low-content videos (P < 0.001). Strong positive associations existed between the number of domains present and DISCERN scores (rho = 0.808; P < 0.01) and between GQS and DISCERN scores (rho = 0.67; P < 0.01). Intraclass coefficient scores ranged between 0.92 and 0.98. Dissatisfaction with the need for long-term retainer wear was a prevalent negative theme in layperson videos. CONCLUSIONS: The content, reliability, and quality of TikTok videos regarding orthodontic retention were poor. The orthodontic profession must use TikTok effectively to ensure it delivers high-quality information relevant to laypersons' concerns.

Ability of piezocision to retain orthodontically moved teeth in a goat model: A split-mouth study.

OBJECTIVES: to evaluate the effectiveness of piezocision in enhancing retention when performed after orthodontic tooth movement. METHODS: Four mature goats had their second incisors removed bilaterally. For each goat, the two sides of the mandible were either treated with piezocision or served as a positive control. Using fixed orthodontic appliance, the first and third incisors on each side were approximated and then retained in place for two weeks. Relapse was measured by the amount of space developed between the approximated incisors after six weeks from the end of the retention period. The periodontal ligament of all incisors was assessed histologically with micro computed tomography and regular hematoxylin and eosin staining. RESULTS: A significantly less relapse was observed in the piezocision group than in the control group (p ≤ 0.05). Bone formation occurs in the vicinity and periphery of the periodontal ligament and thus results in the narrowing of the periodontal ligament. CONCLUSION: A protocol of post-orthodontic retention involving piezocision can be promising to enhance stability of orthodontic treatment outcome.

Comprehensive Effects of Photobiomodulation Therapy as an Adjunct to Post-orthodontic Treatment Care: A Systematic Review.

PURPOSE: To evaluate the comprehensive effects of photobiomodulation (PBM) therapy on teeth after active orthodontic treatment. MATERIALS AND METHODS: This systematic review was conducted according to the PRISMA guidelines. Six databases were electronically searched and screened for eligible human and animal studies published up to August 2020. The risk of bias was assessed based on the Cochrane Handbook for Systematic Reviews of Interventions and Systematic Review Centre for Laboratory Experiment Tool. Two independent reviewers performed all procedures in duplicate. Any disagreement was resolved by discussion or consultation with a third reviewer. RESULTS: A total of 395 records were identified from the initial search up to August 2020. Following screening, 16 full-text articles were reviewed for eligibility (κ > 0.90), and ultimately 9 studies (3 clinical studies and 6 animal studies) were included in this review. The key outcomes observed were 'tooth position maintenance' and 'root resorption rehabilitation'. Two controlled clinical trials and two animal studies supported the preventive effects of PBM therapy on the relapse of post-orthodontic tooth positions, while the other two animal studies reported opposing findings. Regarding root resorption, all evidence supported the rehabilitation potential using PBM therapy for teeth that had undergone orthodontic tooth movement. There was a high risk of bias among studies, except for one randomised controlled trial. Due to the substantial heterogeneity among studies in terms of their types, participants, designs, PBM therapy settings and variables of interest, it was not possible to conduct a meta-analysis; therefore, a qualitative synthesis is presented. CONCLUSION: The quality of evidence for PBM therapy contributing to the maintenance of tooth position or improved dental health after orthodontic treatment remains low. There is considerable controversy over the effects of PBM therapy on orthodontic relapse. However, the use of PBM therapy after orthodontic treatment has promising effects for root resorption rehabilitation and is generally recommended.

What's in a hashtag: A content evaluation of Instagram posts related to orthodontic retention and retainers.

OBJECTIVE: To evaluate and compare the content of posts placed on Instagram by orthodontic treatment providers (OTP) and patients regarding orthodontic retention and retainers. MATERIALS AND METHODS: Six "hashtag" terms related to orthodontic retention were searched on the social media Web site, Instagram. Relevant uploaded posts were evaluated for the presence of nine retainer and retention-related domains. Patient posts were also qualitatively evaluated for themes via discourse analysis. Descriptive and univariate statistical analyses were carried out. Cohen's kappa intrarater reliability testing was performed. RESULTS: Most of the 144 posts that satisfied inclusion criteria were uploaded by OTPs (81.9%). Text and image(s) comprised 86.8% of posts. The most frequently included domain posted by OTPs related to "what is a retainer" and "the importance of wearing a retainer" (49.2%). Posts by OTPs referred to a greater number of domains (P = 0.028), whereas posts by patients recorded comparatively more "quality-of-life"-related content (P = 0.027). Most patient posts were positive (53.8%). The main negative theme within patient posts related to retainer discomfort and the unhappiness associated with the requirement for indefinite retainer wear. The intrarater score was 0.89 for the presence of domains. CONCLUSIONS: OTPs appear to use Instagram for posting orthodontic retention-related information more often than patients. The content of Instagram posts differed between OTPs and patients. OTPs must ensure that the content of their Instagram posts is relevant to the concerns articulated in posts uploaded by patients.

3D Method for Occlusal Tooth Wear Assessment in Presence of Substantial Changes on Other Tooth Surfaces.

Early diagnosis and timely management of tooth or dental material wear is imperative to avoid extensive restorations. Previous studies suggested different methods for tooth wear assessment, but no study has developed a three-dimensional (3D) superimposition technique applicable in cases where tooth surfaces, other than the occlusal, undergo extensive morphological changes. Here, we manually grinded plaster incisors and canines to simulate occlusal tooth wear of varying severity in teeth that received a wire retainer bonded on their lingual surfaces, during the assessment period. The corresponding dental casts were scanned using a surface scanner. The modified tooth crowns were best-fit approximated to the original crowns using seven 3D superimposition techniques (two reference areas with varying settings) and the gold standard technique (GS: intact adjacent teeth and alveolar processes as superimposition reference), which provided the true value. Only a specific technique (complete crown with 20% estimated overlap of meshes), which is applicable in actual clinical data, showed perfect agreement with the GS technique in all cases (median difference: -0.002, max absolute difference: 0.178 mm3). The outcomes of the suggested and the GS technique were highly reproducible (max difference < 0.040 mm3). The presented technique offers low cost, convenient, accurate, and risk-free tooth wear assessment.

Alexithymia Predicts Cognitive Deficits In Patients With Idiopathic Parkinson's Disease.

BACKGROUND: Most of the orthodontic cases require a long period of retention which is usually carried out with the help of fixed retainers (FR). One of the downsides of FR is that these are prone to breakages. The aim of the present study was to identify the frequency and factors associated with failure of fixed spiral wire retainers.. METHODS: A retrospective crosssectional study was conducted using orthodontic files and dental casts of 126 patients from dental clinics of a tertiary care hospital. Descriptive statistics were applied to calculate the frequency and most common site of breakages. Chi-square test was applied to compare the frequency of breakages among age groups and different retainer spans. Independent sample ttest was used to compare the mean overbite in retainer breakage and retainer intact groups. A p-value ≤0.05 was considered as statistically significant. RESULTS: The frequency of retainer breakage was found to be 53.1%. Maxillary retainer breakages were found in 41.3% subjects whereas mandibular retainer failed in 22.2% subjects. The mean survival time of retainer was 8.91±4.57 months. The detachment of the retainer from the tooth surface was the most common occurrence (86%). The most common site of retainer breakage was maxillary canine (32.5%) and mandibular central incisor (12.7%). All the subjects who had retainers extending till maxillary molars encountered breakages.. CONCLUSIONS: A longer retainer span is associated with a greater risk of breakage. Failure rate in the maxillary arch was higher than the mandibular arch. The most common sites were the maxillary canine and mandibular central incisor. The most common pattern was wire detachment.

Fixed Orthodontic Retainers: A Review.

Orthodontic retention is defined as maintaining teeth in optimal aesthetic and functional position after treatment. Despite the necessity of retention phase and the factors influencing the stability of the teeth after orthodontic treatment was discussed by the orthodontist for a long time, it is accepted that a retention phase is essential for stability of orthodontic treatment results nowadays. Therefore, the application of a suitable retention method is important both for prevention of relapse after orthodontic treatment and for increasing patient satisfaction. Removable appliances had been used for many years for retention purposes. Later, fixed retainers were introduced to prevent relapse as having a number of advantages, such as better aesthetics, no need for patient cooperation, effectiveness, and suitability for lifelong retention. However, their need for precise bonding technique, fragility, and tendency to cause periodontal problems by weakening oral hygiene are some of their disadvantages.

Effect of high-frequency vibration on orthodontic tooth movement and bone density.

OBJECTIVES: Previous reports have shown that high-frequency vibration can increase bone remodeling and accelerate tooth movement. The aim of this study was to evaluate the effects of high-frequency vibration on treatment phase tooth movement, and post-treatment bone density at initiation of retention, with cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Thirty patients with initial Class I skeletal relationships, initial minimum-moderate crowding (3-5 mm), treated to completion with clear aligners and adjunctive high-frequency vibration, (HFV group) or no vibration, (Control group) were evaluated. The patients were instructed to change aligners as soon as they become loose. Changes in bone density associated with orthodontic treatment were evaluated using i-CAT cone-beam computed tomography (CBCT) and InVivo Anatomage® software to quantify density using Hounsfield units (HU) between treated teeth in 10 different regions. HU values were averaged and compared against baseline (T1) and between the groups at initiation of retention (T2). RESULTS: The average time for aligner change was 5.2 days in the HFV group, and 8.7 days in the control group (P = 0.0001). There was significant T1 to T2 increase of HU values in the upper arch (P = 0.0001) and the lower arch (P = 0.008) in the HFV group. There was no significant change in average HU values in the upper (P = 0.83) or lower arches (P = 0.33) in the control group. The intergroup comparison revealed a significant difference in the upper, (P = 0.0001) and lower arches (P = 0.007). CONCLUSION: High-frequency vibration adjunctive to clear aligners, allowed early aligner changes that led to shorter treatment time in minimum-moderate crowded cases. At initiation of retention, the HFV group demonstrated statistically significant increase as compared with pre-treatment bone density, whereas control subjects showed no significant change from pre-treatment bone density.