Comparing the effects of Essix and Hawley retainers on the acoustics of speech

Evaluation of the Distortion of Essix Retainer Formed From Biostar Machine Using Intraoral Digital Scans: An In Vitro Study

Introduction Retention is essential to prevent unwanted tooth movement due to growth changes, to allow the gingival and periodontal tissues affected by orthodontic treatment to realign, and to stabilize teeth that have been moved to potentially unstable positions, thus reducing the risk of relapse. This study aimed to evaluate the distortion of Essix retainers over time to enhance their retention and stability. Methods Patients who visited the Department of Orthodontics and Dentofacial Orthopedics at Ranjeet Deshmukh Dental College & Research Centre, Nagpur, India, after completing their orthodontic treatment were included in the study, according to the established inclusion and exclusion criteria. A total of 26 patients participated. Each patient received an Essix retainer fabricated from a Duran+ Biostar round sheet (1 mm thickness) using a Biostar machine based on their post-debonded maxillary cast. The patients were instructed on the correct insertion and removal of the Essix retainer. The inner surface of the retainers was scanned at one month, three months, and six months using an intraoral digital scanner. These scans were analyzed and compared for distortion at different time intervals using Medit software. Results The Essix retainers exhibited varying degrees of distortion at different time intervals. Notably, distortion was more significant in the posterior region compared to the anterior region. Additionally, distortion increased over time, with the least amount observed at one month and progressively worsening by the sixth month. Specifically, the average distortion in the posterior region ranged from 0.133 mm after the first month to 0.304 mm after six months. In contrast, the average distortion in the anterior region was lower, ranging from 0.057 mm at one month to 0.068 mm at six months. Conclusions Distortion was more pronounced on the posterior surface of the Essix retainer compared to the anterior region.

Impact of clear aligner therapy on speech: does clear aligner therapy cause any speech difficulty?

DATA SOURCES

Electronic search was conducted up to September 2021 in three electronic databases including Scopus, Web of Science, and EMBASE. Only studies in English language were selected.

STUDY SELECTION

Prospective and retrospective studies including cohort, cross-sectional, randomized control trials, and qualitative studies were included. Both the inclusion and exclusion criteria were reported. The search in the databases and the selection of the studies were performed independently by two reviewers. The included studies assessed the effects of clear aligner therapy on the speech difficulty.

DATA EXTRACTION AND SYNTHESIS

Data extraction was performed independently by two reviewers. The data from the relevant studies were extracted into a customized Template. The systematic review was carried out and reported based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Details regarding the authors, year of publication, sample size, included participants, age, groups, outcome assessment, results, and inferences were extracted from the selected studies. The quality of the selected studies was assessed based on the relevant guidelines from Cochrane Handbook for Systematic Reviews. The criteria examined sequence generation, allocation concealment, blinding, outcome data, selective reporting, and other sources of bias. Non-randomized studies were assessed using the ROBINS-I tool (Risk of Bias in Non-randomized studies). The strength of evidence was assessed by the evidence grading system developed by the GRADE collaboration as described in the Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

The search identified 283 results. 269 articles were excluded based on their title and abstract after evaluation against the inclusion criteria. 14 articles were assessed in full text. Finally, 7 papers were included in the qualitative analysis. The included studies were 5 cohort studies and 2 randomized clinical studies. 332 patients were examined in the included studies. There were 195 females and 137 males. 191 patients were treated using clear aligner therapy (CAT) while 122 patients were treated using labial fixed appliances and 19 patients were treated using lingual orthodontic treatment. Out of the 191 patients who were treated using CAT, 179 patients were treated using Invisalign (Santa Clara, CA, USA) while 12 patients were treated using Smile Align (Mumbai, India). All seven selected studies examined speech dysfunction. The speech difficulty was assessed through two tools - semiobjective assessment by speech pathologists and professionals and subjective evaluations by the patients themselves through a patient questionnaire that assess the effects of aligners on speech. The risk of bias assessment revealed that two studies had moderate risk of bias while five articles had serious risk of bias. Meta-analysis was not performed due to the high heterogeneity of the included studies. The level of evidence was assessed as low due to the methodological insufficiencies and risk of bias in the included studies. The results showed that both CAT and fixed appliances (FA) resulted in speech difficulties in terms of clarity and delivery of speech that include speech alteration, slurring of words, lisping, and nasality. Some patients who were treated using CAT reported impairment in the lingual space that affected their speech. Lingual FA resulted in more speech difficulty when compared to labial FA and CAT. Aligners caused errors in the articulation of /s/,/z/,/zh/,/sh/,/th/,/ch/. Acoustic analysis revealed /s/ sound appeared most affected. Aligners had an effect on speech while reading, with patients slowing down to their speed to better articulate. The above-mentioned speech difficulties were transient. The included patients normalized their speech within 7-14 days from start of treatment while few patients took 30-60 days to recover.

CONCLUSIONS

Although the likelihood of speech difficulties would be high with CAT, the current evidence states that speech difficulties shown with CAT are similar to those found with FA. However, the patients who were treated using CAT adapt quickly and speech recovers within a few weeks. Time to recovery varied greatly, ranging from a week to two months in certain cases.

Assessment of the effect of vacuum-formed retainers and Hawley retainers on periodontal health: A systematic review and meta-analysis

Background

Recently, increasing attention has been paid to the periodontal health of orthodontic patients in the maintenance stage in clinical practice. The focus of this meta-analysis was to compare the effects of vacuum-formed retainers (VFR) and Hawley retainers (HR) on periodontal health, in order to provide a reference for clinical selection.

Methods

From the establishment of the database until November 2020, a large number of databases were searched to find relevant randomized control trials, including the Cochrane Library databases, Embase, PubMed, Medline via Ovi, Web of Science, Scopus, Grey Literature in Europe, Google Scholar and CNKI. Related literature was manually searched and included in the analysis. Two researchers screened the literature according to relevant criteria. The size of the effect was determined using RevMan5.3 software, and the mean difference and 95% confidence intervals (CI) were used to estimate the results using a random effects model.

Results

This meta-analysis included six randomized controlled trials involving 304 patients. The results of the meta-analysis showed that there was no statistical difference in sulcus probing depth status between the VFR group and the HR group, including at 1, 3, and 6 months. Compared with the VFR group, the HR group showed a lower gingival index at 1 month (mean difference = 0.12, 95%CI: 0.06 to 0.19) and 3 months (mean difference = 0.11, 95%CI: 0.06 to 0.17), while there was no statistically significant difference at 6 months (mean difference = 0.10, 95%CI: -0.07 to 0.27). The plaque index of the HR group also showed a good state at 1 month (mean difference = 0.06, 95%CI: 0.01 to 0.12), 3 months (mean difference = 0.12, 95%CI: 0.08 to 0.16), and 6 months (mean difference = 0.19, 95%CI: 0.09 to 0.29). Subgroup analysis of PLI showed that when all teeth were measured, PLI status was lower in the HR group at 6 months (mean difference = 0.32, 95%CI: 0.18 to 0.46). PLI status was also low for the other teeth group (mean difference = 0.15, 95%CI: 0.08 to 0.22).

Conclusion

Our meta-analysis showed that patients using the Hawley retainer had better periodontal health compared with those using vacuum-formed retainers. However, more research is needed to look at the periodontal health of patients using these two retainers.

Orthodontic retention protocols: an evidence-based overview

In view of the diversity of orthodontic presentations, a single optimal retention protocol does not exist, with approaches tailored based on pre-treatment characteristics, treatment-induced changes and general patient characteristics. However, orthodontic practitioners should be responsive to the best available evidence to formulate optimal retention protocols in terms of appliance type, design and regimen, in particular. Based on a comprehensive search strategy, we discuss fundamental aspects concerning orthodontic retention of particular interest both to orthodontists and general dentists. These include stability and periodontal outcomes, cost-effectiveness, patient experiences, survival and failure rates of retainers, and the duration of retention.

Removable orthodontic retainers: practical considerations

This article provides an overview of removable orthodontic retainers, discussing their history and the different types available, and compares the two most popular removable retainers. Practical information on consent and the clinical steps involved in the provision of removable retainers, as well as suggested wear and care instructions, are also presented.

Orofacial Trauma on the Anterior Zone of a Trumpet's Player Maxilla: Concept of the Oral Rehabilitation-A Case Report

Background: The occurrence of an orofacial trauma can originate health, social, economic and professional problems. A 13-year boy suffered the avulsion of tooth 11 and 21, lost at the scenario. Methods: Three intraoral appliances were manufactured: A Hawley appliance with a central expansion screw and two central incisors (1), trumpet edentulous anterior tooth appliance (2) and a customized splint (3) were designed as part of the rehabilitation procedure. Objectively assessing the sound quality of the trumpet player with these new devices in terms of its spectral, temporal, and spectro-temporal audio properties. A linear frequency response microphone was adopted for precision measurement of pitch, loudness, and timbre descriptors. Results: Pitch deviations may result from the different intra-oral appliances due to the alteration of the mouth cavity, respectively, the area occupied and modification/interaction with the anatomy. This investigation supports the findings that the intra-oral appliance which occupies less volume is the best solution in terms of sound quality. Conclusions: Young wind instrumentalists should have dental impressions of their teeth made, so their dentist has the most reliable anatomy of the natural teeth in case of an orofacial trauma. Likewise, the registration of their sound quality should be done regularly to have standard parameters for comparison.

Comparison of Dentoskeletal Changes, Esthetic, and Functional Efficacy of Conventional and Novel Esthetic Twin Block Appliances among Class II Growing Patients: A Pilot Study

Objective

A twin block appliance used for correction of skeletal Class II malocclusion suffers from undesirable dental effects and bulkiness. To overcome these limitations and the need for more esthetic appearance of this appliance, an esthetic twin block was designed and used in patients. This study aimed to compare dentoskeletal changes and esthetic and functional efficacy in patients treated with conventional and newly designed esthetic twin block (CTB and ETB) appliances using cephalometric measurements and a questionnaire.

Methods

A pilot study with a 2-arm parallel-randomized double-blind clinical trial was conducted on 24 patients (20 males, 4 females) in the age group of 11-13 years. Subjects were treated with CTB (group 1 [G1]: n=12; mean age=11.67±0.49 years) and ETB (group 2 [G2]: n=12; mean age=11.75±0.62 years) appliances. A modified Pancherz analysis was performed to evaluate skeletal and dental changes. The esthetic and functional efficacy was evaluated by a questionnaire using Likert scale. Wilcoxon and Mann-Whitney U tests were employed for intra and intergroup comparisons respectively (p<0.05).

Results

In G1, a significant increase in lower incisor inclination was observed (p<0.05) whereas it was insignificant in G2. The changes were predominantly skeletal in G2 whereas they were both skeletal and dental in G1. ETB was found to be esthetically and functionally acceptable in all the patients while CTB patients were esthetically conscious, lacked confidence and had discomfort and difficulty in eating, chewing and speaking.

Conclusion

ETB had greater skeletal effects with a reduced tendency of lower incisor proclination, was esthetically acceptable, and functionally more comfortable than the CTB.

The origin and evolution of the Hawley retainer for the effectiveness to maintain tooth position after fixed orthodontic treatment compare to vacuum-formed retainer: A systematic review of RCTs

OBJECTIVE

This systematic review aims to summarize the effectiveness and patient compliances of Hawley retainer (HR) compared to vacuum-formed retainers (VFR) and provide the best clinical evidence related to the use of these retainers for maintaining tooth position following fixed orthodontic appliance so that orthodontists can decide which are the most appropriate methods and retainers to use for each individual patient.

MATERIALS AND METHODS

We searched the Cochrane Library, EMBASE, PubMed, Web of Science, Orthodontic journals, and relevant articles for eligible studies. Only RCTs studies were included; no restrictions on publication status or language were applied until May 20, 2019. We collected the study related to the effectiveness of these two retainers. Furthermore, patient-reported outcomes, survival time, cost-effectiveness, occlusal contact, and adverse effect on gingival and speech articulation were also collected.

RESULTS

We finally included fifteen articles in the qualitative synthesis. No significant difference was observed in patients who had worn the retainers on a full-time or part-time, basis in both HR and VFR in terms of the change in arch widths and arch lengths. VFR appeared to be better at preventing relapses of incisor irregularity than HR. Patient satisfaction with VFR was higher than with HR, and there was no difference in survival rates for both types of retainers. In terms of cost-effectiveness, occlusal contacts, and gingival health, there were a few studies with limited evidence to compare these retainers. For speech articulation, VFR was less affected in comparison to HR.

CONCLUSIONS

We found that wearing VFR provides better relapse prevention of incisor irregularity than HR in both arches, indicating their usefulness in clinical practice. However, there is no evidence to show that the pattern of time duration wearing these retainers provides excellent stability. Overall, there are insufficient high-quality RCTs to provide additional evidence, and further high-quality RCTs research is needed.

Performance of Hawley-type retainers: a systematic review of randomized clinical trials

Background

Although post-treatment changes are almost inevitable, and retention has long been recognized as one of the most critical and routine problems faced by orthodontists, there remains a lack of certainty regarding the parameters of any definitive retention protocol following orthodontic treatment.

Objective

To investigate the performance of the Hawley-type retainers.

Search methods

Search without restrictions in 15 databases and hand searching until December 2016.

Selection criteria

Randomized clinical trials comparing the performance of Hawley-type retainers to other removable appliances or comparing different Hawley-type retainers' wearing schedules.

Data collection and analysis

Following study retrieval and selection, data extraction and individual study risk of bias assessment using the Cochrane Risk of Bias Tool took place. The overall quality of the available evidence was assessed with the Grades of Recommendation, Assessment, Development, and Evaluation approach.

Results

Finally, 10 studies were identified involving 854 individuals, followed for up to 1 year after debonding. Eight studies compared subjects using Hawley and clear thermoplastic retainers; another compared Hawley to positioner and, finally, one trial involved individuals allocated to different Hawley appliance wearing schedules. Three studies were considered as being of low, four of unclear, and three of high risk of bias. In general, few differences were observed between the Hawley and other removable retainers regarding outcomes relevant to maxillary and mandibular dental arch measurements, dental arch relationships and occlusal contacts, speech evaluation, patient reported outcomes, adverse effects, and problems related to the appliances, as well as economic evaluation related outcomes. Moreover, no differences were observed between the compared Hawley wearing schedules. Overall, the quality of the available evidence was considered low.

Conclusions

Given the overall quality of the available evidence and the multitude of parameters, which may have affected the results of the included trials, good practice would suggest further research in the respective field in order to increase both the quantity and quality of information available.

Registration

PROSPERO (CRD42015029279).

Funding

No funding was received for the present systematic review.

Investigating the effect of STN-DBS stimulation and different frequency settings on the acoustic-articulatory features of vowels

INTRODUCTION

Parkinson's disease (PD) is the second most frequent progressive neuro-degenerative disorder. In addition to motor symptoms, nonmotor symptoms and voice and speech disorders can also develop in 90% of PD patients. The aim of our study was to investigate the effects of DBS and different DBS frequencies on speech acoustics of vowels in PD patients.

METHODS

The study included 16 patients who underwent STN-DBS surgery due to PD. The voice recordings for the vowels including [a], [e], [i], and [o] were performed at frequencies including 230, 130, 90, and 60 Hz and off-stimulation. The voice recordings were gathered and evaluated by the Praat software, and the effects on the first (F1), second (F2), and third formant (F3) frequencies were analyzed.

RESULTS

A significant difference was found for the F1 value of the vowel [a] at 130 Hz compared to off-stimulation. However, no significant difference was found between the three formant frequencies with regard to the stimulation frequencies and off-stimulation. In addition, though not statistically significant, stimulation at 60 and 230 Hz led to several differences in the formant frequencies of other three vowels.

CONCLUSION

Our results indicated that STN-DBS stimulation at 130 Hz had a significant positive effect on articulation of [a] compared to off-stimulation. Although there is not any statistical significant stimulation at 60 and 230 Hz may also have an effect on the articulation of [e], [i], and [o] but this effect needs to be investigated in future studies with higher numbers of participants.