Journal Of Orthodontics[JOURNAL]
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200 papers
Pseudo transposition of the mandibular lateral incisor to the first premolar space: A literature review and case series.
Humdani A, Higgins S, Kotecha S
J Orthod · 2024 Sep · PMID 37768000 · Publisher ↗
Tooth transposition is the positional interchange of two adjacent teeth, which may be incomplete or complete. The root apex may remain in a normal position despite a severely displaced crown. The aim of this paper is to...
Tooth transposition is the positional interchange of two adjacent teeth, which may be incomplete or complete. The root apex may remain in a normal position despite a severely displaced crown. The aim of this paper is to provide a literature review on the incidence, aetiology and treatment options for pseudo-transposed mandibular incisors. A case series is also presented highlighting the various management techniques that have been utilised in treating five cases of pseudo-transposed mandibular lateral incisors.
Sustainability in Orthodontics.
Patel A, Sood A
J Orthod · 2023 Sep · PMID 37646404 · Publisher ↗
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Editorial.
Harrison J
J Orthod · 2023 Sep · PMID 37646402 · Publisher ↗
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Meet the Author.
Johal A
J Orthod · 2023 Sep · PMID 37646401 · Publisher ↗
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Meet the Author.
Paul N
J Orthod · 2023 Sep · PMID 37646400 · Publisher ↗
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Comparative evaluation of the dentoalveolar effects of three Class II correctors: A finite element analysis study.
Plaza-Ruiz SP, Rojas-Plaza PA, Basto-Tacuma J … +2 more , Velandia-Palacio LA, Jara-López L
J Orthod · 2024 Mar · PMID 37646245 · Publisher ↗
OBJECTIVE: To compare the stress distribution and total strain applied to the dentition, periodontal ligament (PDL) and cortical and trabecular bones by three Class II correctors using finite element analysis. DESIGN: Th...
OBJECTIVE: To compare the stress distribution and total strain applied to the dentition, periodontal ligament (PDL) and cortical and trabecular bones by three Class II correctors using finite element analysis. DESIGN: Three-dimensional analysis of stresses and total strain of the dentition with three Class II correctors. SETTING: Computational study. METHODS: Three-dimensional finite element models of Class II elastics, the Forsus Fatigue Resistant Device (FRD) and the Carriere Motion Appliance (CMA) were constructed from a cone-beam computed tomography (CBTC) image of an orthodontic Class II patient. The distribution of stress (von Mises and principal stress) and the total strain (mm) in maxillo-mandibular dentition, PDL, cortical and trabecular bone were analysed. RESULTS: The highest von Mises yield and the maximum principal stress in the three models were found at the teeth, followed by the cortical bone, trabecular bone and PDL. The maximum stress and total deformation were located at the upper canines and lower molars in the Class II elastics and CMA models, in the upper first molars in the Forsus FRD and CMA, and in the lower first premolars in the Forsus FRD. In addition, stress was distributed in the anterior and posterior regions of the teeth, and the total deformation was found in the distal direction in the upper arch and in the mesial direction in the lower arch. CONCLUSION: The stress concentrations in the three models were located close to the active components of each appliance, producing specific patterns of stress distribution and displacement that should be taken into account when planning the type of appliance to be used for the correction of the Class II malocclusion.
The William Houston gold medal of the Royal College of Surgeons of Edinburgh 2022: Two case reports.
Leck R
J Orthod · 2024 Sep · PMID 37641490 · Publisher ↗
This paper describes the orthodontic treatment of two cases that were successful in winning the William Houston Gold Medal at the Membership in Orthodontics Examinations of the Royal College of Surgeons of Edinburgh in 2...
This paper describes the orthodontic treatment of two cases that were successful in winning the William Houston Gold Medal at the Membership in Orthodontics Examinations of the Royal College of Surgeons of Edinburgh in 2022. Both cases discuss the management of palatally impacted maxillary canines and treatment was initiated during the emerging COVID-19 crisis and completed over a 27-month period. The first case describes the management of a 15-year-old female with a Class II division 1 incisor relationship complicated by a palatally impacted upper left canine, moderate upper and lower arch crowding, and a lower centreline discrepancy with an associated right lateral displacement on closure. Treatment involved open surgical exposure of the impacted canine, a quad helix appliance, premolar extractions, and upper and lower fixed appliances. The second case describes the management of a 14-year-old female with a Class III incisor relationship complicated by bilaterally impacted maxillary canines, impeded eruption of the lower right second molar, moderate lower and severe upper arch crowding, and an upper centreline discrepancy. These case reports aim to demonstrate the high standards of care achieved by Orthodontic Specialty Trainee Registrars in the UK and provide aspirational standards for future trainees.
The effect of text message reminders on compliance with Twin Block appliances: A randomised controlled trial.
Higgins E, Garvey T, Burns A
J Orthod · 2024 Jun · PMID 37528572 · Full text
AIMS: The aim of this study was to evaluate whether text reminders influence patient compliance with Twin Block appliances. The null hypothesis was that there was no statistically significant differences in Twin Block co...
AIMS: The aim of this study was to evaluate whether text reminders influence patient compliance with Twin Block appliances. The null hypothesis was that there was no statistically significant differences in Twin Block compliance between those who receive text reminders and those that do not. DESIGN: Single-blind parallel randomised controlled clinical trial. SETTING: Health Service Executive (HSE) orthodontic outpatient clinic in Dublin, Ireland. PARTICIPANTS: A total of 59 patients aged 11-15 years with a 5a Index of Orthodontic Treatment Need (IOTN grade) starting treatment with Twin Block appliances. METHODS: A computer-generated unstratified allocation sequence was used to randomise the participants into the control group (CG) or the text group (TG). Both groups were asked to wear their appliances full-time. In addition to the same verbal and written instruction received by the CG, the TG received text message reminders, every 3 days, to wear their appliances. The primary outcome measure was wear time reported by Theramon sensors embedded in the appliances. Data on wear time were uploaded from the Theramon sensors onto cloud software. Participants in both groups were asked to fill out wear diaries and submit these at each visit. Treating clinicians and the primary investigator were blinded to the allocation group. Participants were followed up for 4 months. Participants were not blinded to their treatment group. RESULTS: In total, 29 participants were allocated to the CG and 30 to the TG. The data for 53 participants were analysed, 24 from the CG and 29 from the TG. The median hours/day of wear recorded using the Theramon sensors was 13.77 (interquartile range [IQR] = 10.19) for the CG and 17.72 (IQR = 5.62) for the TG. The difference in wear time recorded was not statistically significant ( = 0.16). CONCLUSION: The study concluded that text message reminders had no statistically significant influence on patient compliance with Twin Block appliances.
Three-dimensional comparison of continuous and segmented arch techniques in the traction of palatally impacted canines using a non-linear finite element analysis.
Bou Malhab S, Karam R, Kaddah F … +5 more , El Khoury T, Ghosn N, Khoury E, Kassis A, Ghoubril J
J Orthod · 2024 Jun · PMID 37470224 · Publisher ↗
OBJECTIVE: To compare the three-dimensional (3D) effects of canine traction on the maxillary teeth when using two different traction methods, the continuous and the segmented arch wire techniques; then to test whether ad...
OBJECTIVE: To compare the three-dimensional (3D) effects of canine traction on the maxillary teeth when using two different traction methods, the continuous and the segmented arch wire techniques; then to test whether adding a transpalatal arch (TPA) would affect their response to traction. DESIGN: Finite element analysis. METHODS: A cone-beam computed tomography (CBCT) scan of a patient with bilateral palatally impacted canines was chosen, from which a 3D model was derived and imported into ABAQUS. Two arch wires were modelled, a continuous round one and a segmented rectangular one. Four models were obtained by adding a TPA to both techniques. A 100° imposed rotation was then applied at the intersection between the vertical loop and the horizontal segment of each wire. Initial displacement of the maxillary tooth in the labio-lingual and in the vertical directions was measured. The absolute maximum principal stress of the periodontal ligament (PDL) was also assessed. RESULTS: Traction using a continuous arch wire led to different movement patterns of all teeth, some of them were tipped in a labial direction while others were lingually tipped. Traction using a segmented arch wire resulted in a retroclination of the posterior teeth and a proclination of the anterior teeth with a high level of stress on the premolars' PDL. Adding the TPA only affected the displacement of the first molars. The right side showed a maximum displacement of the first premolar, while the left side showed it on the lateral. The total displacement on the right side was higher than the left side. CONCLUSION: The segmented technique caused a uniform displacement of all teeth while the continuous one showed a non-uniform displacement. The angulation and position of the vertical loop affected the displacement of the maxillary teeth. The addition of a TPA acted only on the first molars.
A review and evaluation of orthodontic brackets, molar bands and orthodontic auxiliaries during orthognathic surgery: A prospective cohort study.
van Ommeren RM, van Riet TC, Ho JT … +2 more , Jonkman RE, Becking AG
J Orthod · 2024 Mar · PMID 37462079 · Full text
OBJECTIVE: The primary aim of this study was to provide a review of the types and frequency of orthodontic brackets, molar bands and orthodontic auxiliaries used for patients undergoing orthognathic surgery. The secondar...
OBJECTIVE: The primary aim of this study was to provide a review of the types and frequency of orthodontic brackets, molar bands and orthodontic auxiliaries used for patients undergoing orthognathic surgery. The secondary aim was to evaluate the risk of failure of these items during orthognathic surgery. METHODS: From three Dutch hospitals, 124 adult patients were included in this prospective cohort study. Five independent researchers collected the data during surgery using a specifically created data extraction form. The type of surgery, surgeon, orthodontist and type of orthodontic bracket, molar band or auxiliary were noted for each tooth. To evaluate their failure risk, the following variables were noted: failure and site; and type and cause of failure. RESULTS: Stainless-steel brackets were the most frequently (75.8%) used bracket type seen in patients undergoing orthognathic surgery. Ceramic brackets were seen in 24.2% of the cases and were only applied in the anterior region. Molar bands were present in 58.9% of the patients and mostly with bands on the first molars in combination with bonded tubes on the second molars. In 32.2% of all cases, one or more failures were noted. One-third of all failures were described as detachment of the molar tube on the most posterior molar. Kobayashi ligatures and powerpins showed the highest risk of failure (odds ratio [OR] 3.70, 95% confidence interval [CI] = 1.91-7.15). No significant difference in failure rate was found between stainless-steel brackets, molar bands (OR 0.34, 95% CI = 0.08-1.43) and ceramic brackets (OR 0.44, 95% CI = 0.14-1.45). CONCLUSION: Stainless-steel brackets, ceramic brackets, molar bands and surgical hooks are suitable for orthognathic cases. Kobayashi ligatures and powerpins had a significantly higher risk of failure so are not recommended for temporary intraoperative maxillomandibular fixation (TIO-MMF).
Orthodontic alignment of ankylosed teeth with aid of surgical luxation: Case series.
Chong JA, Mah EC
J Orthod · 2024 Sep · PMID 37401621 · Publisher ↗
BACKGROUND: Identification of tooth ankylosis before comprehensive orthodontic treatment can be challenging. This case series illustrates different presentations of tooth ankylosis, the importance of early diagnosis, the...
BACKGROUND: Identification of tooth ankylosis before comprehensive orthodontic treatment can be challenging. This case series illustrates different presentations of tooth ankylosis, the importance of early diagnosis, the use of surgical luxation to aid orthodontic alignment of ankylosed teeth and its sequelae. CASE PRESENTATION: All three cases were adolescents: a 14-year-old girl with a highly placed upper left lateral incisor and history of general anaesthesia; a 14-year-old boy with an impacted upper right first premolar and history of dental trauma; and a 13-year-old girl with an infraoccluded upper left central incisor with history of replantation due to avulsion. Iatrogenic malocclusion developed from attempts to align these ankylosed teeth. Subsequently, surgical luxation was performed, and the ankylosed teeth were successfully aligned. However, it was associated with pulp calcification, root resorption and recurrence of ankylosis. CONCLUSION: Surgical luxation and orthodontic alignment of ankylosed teeth can be considered a useful short-term solution to delay the need of surgical removal and teeth replacement.
Class III malocclusion treated with a 3D-printed hybrid hyrax distalizer combined with mentoplate using Alt-RAMEC protocol: A case report.
Kathem SJ, Matras RC, Abbas SOM
J Orthod · 2024 Jun · PMID 37392009 · Publisher ↗
INTRODUCTION: The aim of this report was to assess the skeletal, dental and soft tissue changes in a juvenile patient with a severe class III malocclusion. This case report describes a novel method of class III treatment...
INTRODUCTION: The aim of this report was to assess the skeletal, dental and soft tissue changes in a juvenile patient with a severe class III malocclusion. This case report describes a novel method of class III treatment using skeletal anchorage for maxillary protraction and Alt-RAMEC protocol. PATIENT CONCERNS: The patient did not have any subjective complaints before treatment and there was no family history of class III malocclusion. CLINICAL FINDINGS AND PRIMARY DIAGNOSES: Extra-orally, the patient had a concave profile with a retrusive mid-face and prominent lower lip. The intra-oral examination revealed angle class III malocclusion with a -3-mm overjet. There was no anterior displacement on closure when the patient was assessed clinically. According to the cephalometric analysis, the sagittal jaw relation and Wits appraisal were reduced due to a retrognathic maxilla and prognathic mandible. INTERVENTIONS: The treatment plan involved maxillary protraction, Alt-RAMEC protocol for 10 weeks and upper molar distalisation with a hybrid hyrax distalizer in combination with a mentoplate. The active treatment time was estimated to 18 months followed by 6 months retention with the appliance. OUTCOMES: The sagittal jaw relationship was increased by approximately 9°, mainly due to maxillary advancement of 8 mm and a positional change of the mandible anteroposteriorly. Natural decompensation of the lower incisors was also observed. In addition, both the facial profile and the smile became more harmonious after treatment. The treatment analysis revealed that the changes achieved were mainly skeletal and it was possible to avoid adverse effects on the dentition. CONCLUSION: In conclusion, treatment with a hybrid hyrax distalizer combined with mentoplate using the Alt-RAMEC protocol is effective in correcting the anteroposterior discrepancy in a juvenile class III patient and it is possible to achieve maxillary advancement of 8 mm.
Decision-making patterns among expert and novice orthodontists and oral maxillofacial surgeons in the management of adults with Class III malocclusions and moderate degree of skeletal discrepancies.
Voon KKR, Lim AAT, Wong HC … +2 more , Sim YF, Foong KWC
J Orthod · 2023 Dec · PMID 37357426 · Publisher ↗
OBJECTIVE: To explore the decision-making patterns among expert and novice orthodontists and oral maxillofacial surgeons in the management of adults with Class III malocclusions and moderate skeletal discrepancies. DESIG...
OBJECTIVE: To explore the decision-making patterns among expert and novice orthodontists and oral maxillofacial surgeons in the management of adults with Class III malocclusions and moderate skeletal discrepancies. DESIGN: Self-administered questionnaire survey. SETTING: Faculty of Dentistry, National University of Singapore and the University Dental Cluster, National University Hospital, Singapore. PARTICIPANTS: A total of 55 clinicians, comprising 13 expert orthodontists, 20 novice orthodontists, 10 expert oral maxillofacial surgeons and 12 novice oral maxillofacial surgeons. METHODS: Clinicians assessed six adults with a Class III malocclusion and moderate skeletal discrepancy. They were asked to decide who could be managed exclusively by orthodontic camouflage, who would require combined orthodontic-orthognathic surgery as the only viable treatment, or who could be offered both treatment options. RESULTS: The study found variable decision-making patterns among the clinicians in each case. Only 18.2%-40.0% of clinicians agreed that the cases selected were of moderate skeletal discrepancies and could be offered both treatment options whereas the rest were either more inclined to recommend orthodontic camouflage or orthognathic surgery. Intra-clinician agreement (n = 20) was only fair (Kappa value = 0.31). There was only slight inter-clinician agreement (n = 55) on their clinical decisions (Kappa value = 0.10). Clinical experience and dental specialty did not significantly influence clinicians' decisions. Oral and maxillofacial surgeons were 1.98 times more likely to indicate orthognathic surgery as the only viable treatment compared to the orthodontists (95% confidence interval = 1.15-3.42). CONCLUSION: Variability in the patterns of decision-making for adults with a Class III malocclusion and moderate skeletal discrepancy was observed among the clinicians with low repeatability and agreement.
Accuracy of conventional versus cone-beam CT-synthesised lateral cephalograms for cephalometric analysis: A systematic review.
Raj G, Raj M, Saigo L
J Orthod · 2024 Jun · PMID 37340975 · Publisher ↗
OBJECTIVE: To assess the accuracy of cone-beam computed tomography (CBCT)-synthesised lateral cephalograms (CSLCs) compared with conventional lateral cephalograms for cephalometric analysis in human participants and skul...
OBJECTIVE: To assess the accuracy of cone-beam computed tomography (CBCT)-synthesised lateral cephalograms (CSLCs) compared with conventional lateral cephalograms for cephalometric analysis in human participants and skull models. METHODS: The authors performed a search of PubMed, Scopus, Google Scholar and Embase databases on 4 October 2021. Included studies met the following criteria: published in English; compared conventional lateral cephalograms and CSLCs; assessed hard- and soft-tissue landmarks; and were performed on human or skull models. Data extraction from eligible studies was performed by two independent reviewers. The quality of evidence was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist tool - diagnostic accuracy studies. RESULTS: A total of 20 eligible articles were included in this systematic review. Of these 20 studies, 17 presented with a low risk of bias, while three were found to have a moderate risk of bias. Hard- and soft-tissue analyses were evaluated for each imaging modality. The findings reveal that CSLCs are accurate and comparable to conventional lateral cephalograms for cephalometric analysis and demonstrate good inter-observer reliability. Four studies reported a higher accuracy with CSLCs. CONCLUSION: Overall, the diagnostic accuracy and reproducibility of CSLCs were comparable to conventional lateral cephalograms in cephalometric analysis. It is justified that patients who have an existing CBCT scan do not need an additional lateral cephalogram, minimising unnecessary radiation exposure, expenses and time for the patient. Larger voxel sizes and low-dose CBCT protocols can be considered to minimise radiation exposure. REGISTRATION: This study was registered with PROSPERO (CRD42021282019).
Characteristics of orthognathic multidisciplinary team clinics in England. Part 1: A questionnaire survey.
Brannen S, Rolland S, Cala A … +2 more , Vernazza CR, Paul N
J Orthod · 2023 Sep · PMID 37338131 · Publisher ↗
BACKGROUND: Orthognathic clinics across England are currently run in a multidisciplinary team (MDT) format. It is, however, likely that there is a large variation in the style of these clinics and care pathways for ortho...
BACKGROUND: Orthognathic clinics across England are currently run in a multidisciplinary team (MDT) format. It is, however, likely that there is a large variation in the style of these clinics and care pathways for orthognathic patients across the country. This was a cross-sectional, online questionnaire with a primary aim to obtain information on the way orthognathic care is currently delivered throughout England. The secondary objectives were to determine the compliance to the minimum dataset for record collection. The questionnaire, disseminated to orthodontic consultants, detailed 27 items split into waiting lists for new patients, mechanics of the clinic, support for patients and record collection. RESULTS: A total of 36 participants responded (one was excluded) to give a total of 35 questionnaire responses. Descriptive statistics were used to analyse the data. Of the participants, 34% followed up their patients as per the commissioning guidelines at 1, 2 and 5 years after treatment. Of the participants, 20% said patients' mental health would be screened before adding them to a waiting list, with 26% of participants stating screening was not undertaken for all patients. Of the participants, 11% had available access to psychological support during the MDT meeting and 20% recorded the minimum dataset at the follow-up intervals. CONCLUSION: There are inconsistencies in the orthognathic MDT design across England. Acceptance criteria, support services available and records collected for patients showed substantial variation, highlighting the limited guidance offered by the commissioning guidelines and the potential need to revise the minimum dataset.
Evidence that ectopic upper third molars can result in upper second molar impactions: A case series.
Chawla R, Garcha P, Lyne A … +1 more , Sheriteh Z
J Orthod · 2024 Jun · PMID 37278020 · Publisher ↗
INTRODUCTION: The aim of these four case reports was to illustrate the presence of potential upper second molar impactions associated with ectopic third molars and to highlight that some cases have an atypical radiograph...
INTRODUCTION: The aim of these four case reports was to illustrate the presence of potential upper second molar impactions associated with ectopic third molars and to highlight that some cases have an atypical radiographic presentation. CASE PRESENTATIONS: Four patients (age range = 7-12 years) with various malocclusions presented to the paediatric and orthodontic departments for treatment to address their presenting complaints. Incidental radiographic findings demonstrated potentially impacted upper second molars associated with ectopic third molars. In all of these cases, a joint paediatric-orthodontic approach was adopted to address their dental health, prevent upper second molar impaction and to treat their malocclusion. DISCUSSION: Careful and systematic review of radiographic imaging was necessary in order to diagnose these cases correctly. These cases demonstrated that it was not always simple to determine impactions, particularly as identification of third molar crypts can be difficult. On occasion, sequential radiographic monitoring is advocated, particularly in patients in the mixed dentition; however, clinicians must be mindful of the risks of ionising radiation as it is not routine practice to irradiate a patient multiple times. CONCLUSION: The series of cases highlights the need for a systematic assessment of OPTs to identify ectopic upper third molars. The input from radiologists is invaluable and if necessary, supplemental three-dimensional cone-beam computed tomography can be performed.
Effectiveness of dental monitoring system in orthodontics: A systematic review.
Sangalli L, Alessandri-Bonetti A, Dalessandri D
J Orthod · 2024 Mar · PMID 37278017 · Publisher ↗
BACKGROUND: Dental monitoring (DM) constitutes a recent technological advance for the remote monitoring of patients undergoing an orthodontic therapy. Especially in times of health emergency crisis, the possibility of re...
BACKGROUND: Dental monitoring (DM) constitutes a recent technological advance for the remote monitoring of patients undergoing an orthodontic therapy. Especially in times of health emergency crisis, the possibility of relying on remote monitoring could be particularly useful. OBJECTIVES: To assess the effectiveness of DM in orthodontic care. ELIGIBILITY: Studies conducted on healthy patients undergoing orthodontic care where DM was applied, assessing a change in treatment duration, emergency appointments, in-office visits, orthodontic relapse, early detection of orthodontic emergencies and improvement of oral health status. INFORMATION SOURCES: PubMed, Web of Science and Scopus were searched for publications until November 2022. RISK OF BIAS: Quality assessment was performed with the STROBE Checklist. DATA EXTRACTION: Data were extracted independently by two reviewers, and discrepancies were resolved with a third reviewer. INCLUDED STUDIES: Out of 6887 records screened, 11 studies were included. SYNTHESIS OF RESULTS: DM implemented to the standard orthodontic care was found to significantly decrease the number of in-office visits by 1.68-3.5 visits and showed a possible trend towards improvement of aligner fit. Conversely, evidence does not support a reduction of treatment duration and emergency appointments. The assessment of the remaining variables did not allow any qualitative synthesis. CONCLUSIONS: This review highlighted that DM implemented to standard orthodontic care can significantly decrease the number of in-office visits and may potentially result in an improved aligner fit. Due to the low quality of most of the included studies and the heterogeneity of the orthodontic system where DM was applied, studies with different investigation team and rigorous methodology are advocated.
A new orthodontic force simulation system with a simulated periodontal ligament to measure the delivered force at the root apex.
Tochigi K, Arai K
J Orthod · 2023 Dec · PMID 37278012 · Publisher ↗
OBJECTIVE: To develop a new orthodontic force simulation system with a simulated periodontal ligament (PDL) that enables measurement of the delivered force at the root apex and to clarify the relationship between the app...
OBJECTIVE: To develop a new orthodontic force simulation system with a simulated periodontal ligament (PDL) that enables measurement of the delivered force at the root apex and to clarify the relationship between the applied orthodontic force and the delivered force at the root apex. DESIGN: In vitro study. SETTING: Orthodontics department of a university, Tokyo, Japan. METHODS: A new orthodontic force simulation system that enables measurement of the force at the root apex of the maxillary central incisor, was developed. Lingual and intrusion movements were simulated with applied orthodontic force at three levels: 50, 100 and 200 gf. The delivered forces at the root apex were compared between the two movements. Furthermore, the ratio of delivered force at the root apex to the applied orthodontic force (the apex force ratio) was calculated. RESULTS: The magnitudes of delivered forces at the root apex were significantly greater in intrusion movement than in lingual movement ( < 0.01). The apex force ratios were in the range of 47.3%-56.2% for lingual movement and 85.6%-86.2% for intrusion movement. CONCLUSION: The present study, of a newly developed orthodontic force simulation system, showed that the characteristics of the delivered force at the root apex differed according to the direction of tooth movement.
Effect of occlusal hypofunction on centre of resistance in maxillary central incisor using the finite element method.
Kuharattanachai K, Jotikasthira D, Rangsri W … +1 more , Tripuwabhrut K
J Orthod · 2024 Mar · PMID 37269106 · Publisher ↗
OBJECTIVES: To determine differences in the location of centre of resistance (Cres) between functional and hypofunctional teeth and to evaluate the relationship between the pulp cavity volume and locations of the Cres, u...
OBJECTIVES: To determine differences in the location of centre of resistance (Cres) between functional and hypofunctional teeth and to evaluate the relationship between the pulp cavity volume and locations of the Cres, using the finite element (FE) method. DESIGN: Retrospective cohort study. PARTICIPANTS: FE models of right maxillary central incisor, derived from cone-beam computed tomography (CBCT) images of 46 participants, were divided into normal function (n = 23) and hypofunction (n = 23) groups using anterior overbite and cephalometric measurements. METHODS: Measurements of the tooth and pulp cavity volume were made from the CBCT. Cres levels were presented as percentages of the root length from the root's apex. All data were analysed and compared using the independent t-test ( < 0.05). The relationship between the location of Cres and volume ratios were evaluated statistically. RESULTS: The means of the pulp cavity/tooth volume and root canal/ root volume ratio of the maxillary central incisor in the anterior open bite group were significantly greater than those in the normal group. The average location of Cres in the anterior open bite group was 0.6 mm (3.7%) apically from the normal group, measured from root apex. The difference was statistically significant ( < 0.01). There was a significant correlation between root canal/root volume ratio and locations of Cres (r = -0.780, < 0.001). CONCLUSIONS: The Cres in the hypofunctional group was located more apical than the functional group. As the pulp cavity volume increased, the level of Cres shifted apically.
Contemporary Twin Block appliance wear protocols: A survey of UK orthodontists.
Ong Q, Anwar H, El-Angbawi A
J Orthod · 2024 Mar · PMID 37246461 · Publisher ↗
OBJECTIVE: This study was undertaken to determine contemporary trends in the use of the Twin Block appliance among UK orthodontists, including the wear time currently prescribed. In addition, the study explored if there...
OBJECTIVE: This study was undertaken to determine contemporary trends in the use of the Twin Block appliance among UK orthodontists, including the wear time currently prescribed. In addition, the study explored if there had been any change in wear time prescribed, considering recent research evidence proposing part-time wear. DESIGN: Cross-sectional, online survey. PARTICIPANTS: Members of the British Orthodontic Society (BOS). METHODS: The questionnaire was emailed to all BOS members in November 2021 and hosted on the QualtricsXM platform. The questionnaire was piloted for content validity and tested for reliability. RESULTS: A response rate of 19% was attained. Nearly all (n = 244, 99%) participants used the Twin Block, and 90% (n = 218) prescribed full-time wear including/excluding eating. Although the majority (n = 168, 69%) had not made changes to their wear time prescriptions, nearly one-third (n = 75, 31%) had. Those who reported a change in their prescriptions currently prescribe less wear time than before, and commonly quoted 'research evidence' as the reason. A wide range in success rates (41%-100%) was reported, with patient compliance as the main reason for treatment discontinuation. CONCLUSION: The Twin Block is a popular functional appliance among orthodontists in the UK, originally designed by Clark to be worn full time to maximise functional forces applied to the dentition. However, this wear regime may place considerable strain on patient compliance. Most participants prescribed full-time Twin Block wear excluding eating. Approximately one-third of orthodontists made changes to their wear time prescriptions during their practising career, and currently instruct less wear time than before.
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