Evaluation of modified clear Twin Block aligner in treating adolescents with skeletal class II malocclusion: A two-centre cephalometric study.

INTRODUCTION: The purpose of this study was to evaluate the therapeutic effect of modified clear Twin Block (CTB) aligner and traditional twin block (TB) appliance from skeletal, dentoalveolar and soft tissue changes in adolescents with skeletal class II malocclusion. METHODS: A total of 80 adolescents, included in this study from two medical centres, were distributed into CTB group, TB group and control group based on the treatment they received. Lateral cephalograms at pre-treatment (T1) and post-treatment (T2) were measured by modified Pancherz's cephalometric analysis, and dentoskeletal and soft tissue changes were analysed by independent-sample t-test, paired-sample t-test, ANOVA test and Scheffe's Post Hoc test. RESULTS: Seventy-five adolescents completed the study, including 32 in the CTB group, 32 in the TB group and 11 in the control group. Both CTB and TB treatment showed significant differences in most dentoskeletal and soft tissue measurements. Compared with the control group, improvements were observed in class II molar relationship through significant different in S Vert/Ms-S Vert/Mi in the CTB group (P < .01) and the TB group (P < .001), as well as deep overjet through significant different in S Vert/Is-S Vert/Ii in the CTB group (P < .001) and the TB group (P < .001). Besides, the CTB group also showed less protrusion of lower incisors and resulted in a more significant improvement in profile with fewer adverse effects on speaking, eating and social activities. CONCLUSIONS: For adolescents with skeletal class II malocclusion, CTB appliance was as effective as TB on improving dentoskeletal and soft tissue measurements, featuring more reliable teeth control and patient acceptance.

Assessing the immediate impact of Twin-block appliance insertion on adolescents' sleep using a wearable device.

OBJECTIVE: This prospective clinical study aimed to evaluate the immediate impact of Twin-block appliance insertion on the sleep of adolescents using a wearable device. MATERIALS AND METHODS: A total of 24 girls, aged 11-13 years, with Class II division 1 molar relationship, skeletal class 2 malocclusion (ANB ≥5) and overjet measuring ≥5 mm were selected. Exclusion criteria included a history of previous orthodontic treatment, systemic disease, irregular sleep pattern, obstructive sleep apnea, medical history of breathing disorders, or concurrent use of medications. Participants wore a wearable device to measure sleep parameters, including deep sleep, light sleep, minutes awake during sleep, wake-up times, bedtimes and total sleep times. The participants wore the device for 10 days prior to Twin-block insertion and sleep data were collected for another 10 days after insertion. RESULTS: Following the insertion of the Twin-block appliance, there was a highly statistically significant shift in bedtime and wake-up time to later hours (P < .001). All participants experienced a highly significant delay in bedtime compared to the recommended 10 pm time (P < .001). Additionally, there was a significant increase in the duration of light sleep (P < .05). However, the effect on deep sleep, minutes awake during sleep and sleep duration was not statistically significant. None of the sleep parameters tested showed statistically significant changes between the first 5 days after Twin-block insertion with the subsequent 5 days. CONCLUSION: The immediate insertion of the Twin-block appliance disrupts sleep onset, wake-up time and light sleep during the specified period of 10 days.

Effect of functional appliances on sleep-disordered breathing in Class II division 1 malocclusion children: Randomized controlled trial.

OBJECTIVES: A randomized controlled trial was undertaken to investigate the orthopaedic effect of functional appliances on the pharyngeal airway space and nocturnal breathing of children with skeletal class II due to mandibular retrusion. MATERIALS AND METHODS: Forty patients were randomized into a 1:1 ratio study (Twin block) group and a control (fixed appliance) group. Each group included equal numbers of boys and girls. Diagnosis with sleep-disordered breathing was not an inclusion criterion. The duration of the trial was 12 months (T0 - T12). Eligibility criteria included skeletal Class II division 1 malocclusion with mandibular retrognathism, SNA ≥82, SNB ≤78, ANB ≥4, overjet ≥6 mm, and patients in circumpubertal stage CVM2 and CVM3. The main outcomes were pharyngeal airway volume, oxygen desaturation index (ODI), and maximum expiratory pressure (MEP), while the secondary outcomes were skeletal and dental changes of the maxilla and mandible. Randomization was accomplished with random blocks of 20 patients with allocation concealed in sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for data analysis of radiographic measurements and data extracted from the pulse oximeter. RESULTS: The mean age of the patients was 10 ± 1.5 and 10 ± 1.2 at (T0) for the Twin Block and the control groups, respectively. The changes in the oropharyngeal (2.66 cc and 0.056; P = .03) and nasopharyngeal (1.3 cc and 0.84; P = .053) airway volumes for the Twin block and control groups, respectively, were significantly different for the oropharynx. There was a significant decrease in ODI by [median -3.55 (-5.05 to 0.50); P ≤ .001] and a significant increase [median 45 (0.0-110); P ≤ .001] in MEP for the Twin block group. A significant inverse correlation (r = -.589; P = .006) could be found between the total volume of the oropharynx and ODI. No serious harm was observed. CONCLUSIONS: The Twin block group showed significant change in oropharyngeal airway volume and improvement of nocturnal breathing. REGISTRATION: This trial was registered at https://www. CLINICALTRIALS: gov, registration number NCT04255511.

Clinical effects of twin-block combined with maxillary expansion on the upper airway in adolescents with Class II malocclusion.

BACKGROUND: Class II malocclusion, particularly class II division 1, poses a significant orthodontic challenge with implications for both aesthetics and health. This study aimed to explore the impact of twin-block (TB) combined with maxillary expansion treatment (TB-ME) on upper airway dimensions and inflammatory profiles in adolescents with skeletal Class II Division 1 malocclusion in adolescent. METHODS: Ninety-two eligible patients were randomly assigned to two groups: TB-ME treatment and traditional McLaughlin Bennett Trevisi (MBT) straight-wire orthodontic treatment (Control). Cephalometric lateral X-ray scans were conducted before and after treatment to assess skeletal changes, including SNA, ANB, and SNB angles, which are essential to assess the anteroposterior relationships of the maxilla and mandible to the cranial base. We also measured the upper airway volumes and areas. Concentrations of inflammatory factors including intercellular adhesion molecule 1 (ICAM-1), matrix metallopeptidase 2 (MMP2), and interleukin 8 (IL-8) of gingival crevicular fluid analysis (GCF) were detected by enzyme-linked immunosorbent assay. RESULTS: TB-ME treatment induced significant improvement in cephalometric parameters, including a decrease in SNA and ANB angles and an increase in SNB angle. Upper airway volumes and areas increased significantly in both groups, with TB-ME showing greater improvements. GCF analysis revealed a reduction in ICAM-1, MMP2, and IL-8 concentrations in the TB-ME group compared to the Control group. CONCLUSIONS: TB-ME treatment demonstrates multifaceted improvements in skeletal malocclusion, upper airway dimensions, and inflammatory profiles in adolescents with class II division 1 malocclusion, showing the promise of TB-ME in addressing the complexities associated with class II malocclusion.

Comparison of Twin Block appliance and Herbst appliance in the treatment of Class II malocclusion among children: a meta-analysis.

BACKGROUND: Our meta-analysis aimed to evaluate the efficacy of applying Herbst and Twin Block appliances in the treatment of Class II malocclusion among children. METHODS: Databases, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), China VIP Database (VIP), and Wanfang were thoroughly searched from inception to August 9, 2023. The outcomes included skeletal, dental, and soft tissue changes. The weighted mean difference (WMD) was used as the effect indicator, and the effect size was expressed with a 95% confidence interval (CI). The heterogeneity of each outcome effect size was tested, and the heterogeneity statistic I2 ≥ 50% was analyzed by the random-effect model, otherwise, the fixed-effect model was conducted. Sensitivity analysis was performed. RESULTS: A total of 12 studies involving 574 patients were included in this meta-analysis. Herbst appliance had a statistically significant increase in mandibular body length (WMD: 1.44, 95% CI: 0.93 to 1.96, P < 0.001) compared with the Twin Block appliance. More increases in angle and distance of L1 to mandibular plane (MP) were found in the Herbst appliance compared with the Twin Block appliance. Significant and greater improvements in molar relationship (WMD: 0.79, 95% CI: 0.28 to 1.29, P = 0.002), posterior facial height (WMD: -1.23, 95% CI: -2.08 to -0.38, P = 0.005), convexity angle (WMD: -1.89, 95% CI: -3.12 to -0.66, P = 0.003), and Sella-Nasion plane angle (U1 to SN) (WMD: 3.34, 95% CI: 2.25 to 4.43, P < 0.001) were achieved in the Twin Block appliance. Herbst and Twin Block appliances produced similar effects in the skeletal and dentoalveolar changes including Sella-Nasion-point A (SNA), Sella-Nasion-point B, point A-Nasion-point B (ANB), overjet, and overbite. CONCLUSION: As the findings revealed both Herbst and Twin Block appliances contributed successfully to the correction of Class II malocclusion. Compared with the Twin Block appliance, the Herbst appliance may have more advantages in mandibular bone movement. Twin Block therapy resulted in more improvement in the aesthetics of the face.

Contemporary Twin Block appliance wear protocols: A survey of UK orthodontists.

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.

Effects of twin-block appliance on upper airway parameters in OSA children with class II malocclusion and mandibular retrognathia: a CBCT study.

Twin-block appliance had been advocated as a potential treatment option in paediatric obstructive sleep apnoea (OSA) due to their favourable effect in enhancing upper airway parameters and improving OSA symptoms. The aim of this study was to evaluate the effect of twin-block appliance therapy on upper airway parameters/dimensions and the apnoea-hypopnea indexes (AHIs) in OSA children with class II mandibular retrognathic skeletal malocclusion using cone-beam computed tomography. This prospective longitudinal study comprised 34 polysomnography-proven OSA growing children with class II mandibular retrognathic skeletal malocclusion between the ages of 8 and 12 years who had completed myofunctional twin-block therapy and matched corresponding controls. The upper airway was segmented into the nasopharynx, oropharynx, and hypopharynx, and the effect of twin-bock treatment on upper airway parameters/dimensions was assessed pre- and posttreatment using CBCT analysis, while a second standard overnight PSG was performed to determine changes in the AHI. At the nasopharynx level, minimal (nonsignificant) increases in all variables were observed within the twin-block group and between the groups (P > 0.05). At the level of the oropharynx, all variables increased significantly in the treatment group and between groups (P < 0.001), but these increases were nonsignificant in the control group. At the level of the hypopharynx, only the minimum cross-sectional area (MCA) increased significantly in the treatment group (P = 0.003). The change in MCA was also significant between the groups (P = 0.041). In addition, the upper airway length increased significantly in the twin-block group (P = 0.0154), and the AHI decreased by 74.8% (P < 0.001). CONCLUSION: Correction of class II mandibular retrognathic skeletal malocclusion with twin-block appliance resulted in a significant increase in upper airway volume, MCA, anteroposterior and lateral distances of the MCA at the level of the oropharynx, MCA at the level of the hypopharynx and upper airway length, and a significant decrease in AHI, but it had no effect on nasopharynx parameters. WHAT IS KNOWN: • CBCT imaging has been shown to be an effective and precise diagnostic tool for analyzing the upper airways and craniofacial structures. • Twin block appliance may be an effective treatment modality in children with OSA. WHAT IS NEW: • Minimal cross-sectional area of upper ways may be the most relevant potential parameter when explaining how the upper airway anatomy plays role of in the pathogenesis of pediatric OSA. • Twin block appliance induced favorable changes in upper airway morphology (oropharynx area mainly) and respiratory parameters in OSA children with class II malocclusion.

Effects of Twin-Block with an expanding device on the upper airway in growing children with skeletal class II malocclusion-a retrospective study based on the consistency of three-dimensional and two-dimensional data.

OBJECTIVES: Skeletal class II malocclusion is one of the most common malocclusions. Among the functional appliances for skeletal class II malocclusion, the Twin-Block appliance with a maxillary expander is effective in repositioning the mandible forward. In this study, we focused our efforts on investigating the effects of Twin-Block appliances with maxillary expanders on the upper airway in growing children with skeletal class II malocclusion by tracing and measuring lateral cephalograms after evaluating the consistency of three-dimensional CBCT data and two-dimensional lateral cephalogram data. MATERIALS AND METHODS: A total of 102 patients ranging from 9 to 15 years old (11.37 ± 2.80, male/female ratio = 1:1) with skeletal class II malocclusion were selected to evaluate the consistency of CBCT data and lateral cephalogram data. The strongly and moderately correlated segments were then selected to study the effects of Twin-Block with a maxillary expander on the upper airway in 66 growing children with skeletal class II malocclusion (11.31 ± 1.23 years old, male/female ratio = 1:1) by lateral cephalograms. RESULTS: The results showed a strong significant correlation in the nasopharynx (r = 0.708) and moderate significant correlations in the overall upper airway (r = 0.641), palatopharynx (r = 0.553), and glossopharynx (r = 0.575) but a weak correlation in the hypopharynx (r = 0.323). The corresponding determination coefficient (R2) was also determined by scatter plot analysis. Moreover, compared with the pretreatment data (T1), the total area of the upper airway and the areas of the nasopharynx, palatopharynx, and glossopharynx after functional treatment (T2) increased statistically and significantly. CONCLUSIONS: Lateral cephalograms can reflect the volume of the nasopharynx and oropharynx in skeletal class II children to a certain extent, while Twin-Block appliances with maxillary expanders can widen the volume of the nasopharynx and oropharynx significantly. CLINICAL RELEVANCE: The lateral cephalogram is reliable for analyzing the nasopharynx, palatopharynx, and glossopharynx in orthodontic clinical practice. Twin-Block appliances with maxillary expanders have a positive effect on skeletal class II patients with airway stenosis.

Dentoalveolar, skeletal, pharyngeal airway, cervical posture, hyoid bone position, and soft palate changes with Myobrace and Twin-block: a retrospective study.

BACKGROUND: The primary aim of this study was to evaluate the dentoalveolar, skeletal, pharyngeal airway, cervical posture, hyoid bone position, and soft palate effects of the Myobrace and Twin-block appliances. The second was to compare them in terms of ease of use by assessing the factors that may influence patient compliance. METHODS: The study included thirty-six Class II division 1 patients (19 females, 17 males; mean age, 12.14 ± 1.23) who had previously been treated in the Orthodontic Clinic at Sivas Cumhuriyet University Faculty of Dentistry. The patients were divided into two groups: Group 1: Myobrace (n = 18), and Group 2: twin block (n = 18). The effects of the appliances on the skeletal, dentoalveolar, soft tissue, craniocervical, and other anatomic structures were assessed using 46 measurements (22 linear and 24 angular), on pre and post-treatment cephalometric radiographs. AudaxCeph 5.0 software (Ljubljana, Slovenia) was used for the analysis. To analyze the changes after one year of treatment, a paired sample t-test and Wilcoxon signed-rank test were used. Intergroup comparison was performed using the Student t-test and the Mann-Whitney U test. RESULTS: In the Myobrace and Twin-block groups, there was a significant increase in SNB (°) (p = 0.004, p = 0.001), IMPA (°) (p = 0.005, p = 0.001) and a significant drop in U1/SN (°) (p = 0.021, p = 0.005). The lengths of Cd-Gn (mm), Go-Pg (mm), and Cd-Go (mm) increased significantly in the Twin-block group (p = 0.003, p = 0.010, p = 0.001), whereas the Myobrace group did not change. Similarly, there was no significant difference in pharyngeal and soft palate measurements in the Myobrace group but a statistically significant decrease in SP length and angle in the Twin-block group (p = 0.001, p = 0.006). Increases in SN/OPT (°) (p = 0.032, p = 0.001) and SN/CVT (°) (p = 0.012, p = 0.001) were statistically significant in both groups. Myobrace was more difficult to use while sleeping, whereas the twin block caused more nausea. CONCLUSIONS: Both appliances can be used for mandibular advancement. The Twin-block appliance, on the other hand, was more effective and patient-friendly.

Comparison of invisalign mandibular advancement and twin-block on upper airway and hyoid bone position improvements for skeletal class II children: a retrospective study.

BACKGROUND: This study is to evaluate and compare the improvement of upper airway morphology and hyoid bone position in children with Class II mandibular retrusion treated with Invisalign mandibular advancement (MA) and Twin-Block (TB) appliances, utilizing cone beam computed tomography (CBCT). METHODS: 32 children aged between 8 and 11.5 years old were included in this study, with an average age of 10.2 years old. These children were divided into two groups, MA and TB, with 16 children in each group. Changes in upper airway morphology and hyoid bone position before and after treatment were analyzed using CBCT. RESULTS: (1) Changes in upper airway before and after treatment: the oropharynx volume (Or-V), the oropharynx minimum cross-sectional area (Or-mCSA), the hypopharynx volume (Hy-V), and the hypopharynx minimum cross-sectional area (Hy-mCSA) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05) compared to pre-treatment status. (2) Changes in hyoid bone position before and after treatment: The distances between H point and third cervical vertebra (H-C3), H point and pogonion (H-RGN), H point and mandibular plane (H-MP), H point and Frankfort horizontal plane (H-FH), H and S point (H-S), and H point and palatal plane (H-PP) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05). CONCLUSION: Both MA and TB appliances effectively improved the structural narrowness of the upper airway and reduced respiratory resistance, thus improving breath quality. However, MA showed more effectiveness in improving the narrowest part of the hypopharynx compared to TB. Both appliances also promoted anterior downward movement of the hyoid bone, which opens the upper airway of the oropharynx and hypopharynx and helps the upper airway morphology return to normal range.

Cephalometric changes in pharyngeal airway dimensions after functional treatment with twin block versus myobrace appliances in developing skeletal class II patients: a randomized clinical trial.

BACKGROUND: Several appliances have been used for correction of developing skeletal Class II, including different myofunctional appliances as Twin block (TB)as well as the new pre-fabricated Myobrace (MB) appliance. However, the effects of these devices on the pharyngeal airways have not been compared in the literature. Thus, the aim of this study was to compare the effects of two Class II correction appliances; TB and MB on the sagittal pharyngeal airway dimension (SPAD), including the nasopharyngeal airway area (NPAA), the oropharyngeal airway area (OPAA), and the laryngopharyngeal airway area (LPAA). METHODS: This is a two parallel arms randomized comparative clinical trial. Twenty-six children of 9-12 years with Skeletal Class II malocclusion due to mandibular deficiency and normal maxillary growth as confirmed by lateral cephalometric X-ray readings (ANB angle > 4° and SNB angle < 78) and Cervical vertebral maturational index (CVMI) 1 or 2 were randomly assigned into two equal groups. Group I: TB, Group II: MB (prefabricated functional appliance, Myofunctional Research Co., Australia). Lateral cephalograms were taken for all patients in both groups before treatment (T1) and after treatment (6 months later) (T2). The primary aim was to assess pre and post treatment changes in the SPAD in each group, and compare between the two study groups. The secondary aim was to evaluate the sagittal skeletal measurements such as the SNA, SNB, ANB, Wits appraisal, as well as vertical skeletal measurements represented by the Frankfurt-mandibular plane angle (FMA) measured pre- and post-treatment. The independent samples t-test was used to compare the two study groups, and the mean difference and 95% confidence intervals (CI) were computed. The paired samples t-test was used to compare various parameters between T1 and T2 within each group. The cutoff for significance was p-value < 0.05. Data were analyzed using IBM SPSS for Windows (Version 26.0). RESULTS: By Comparing changes in airway measurements within each group, it was found that NPAA, OPAA, and LPAA increased significantly after treatment within each group of MB and TB. TB group showed significantly higher mean difference (T2-T1) in both NPAA and OPAA than MB group with 28.39 (± 56.75) and 40.46 (± 52.16) respectively. The increase in LPAA values was not statistically significant at (T2-T1) between both groups. Regarding skeletal changes, there was a significant increase in the SNB values between T1 and T2 within each group with 2.82 (± 3.32) for MB group and 3.79 (± 3.06) for TB group Moreover, there was a significant decrease in the ANB values between T1 and T2 within each group by 2.42 (± 2.70) for MB group and 3.06 (± 1.14) for TB group. Similarly, there was a significant decrease in the ANB values between T1 and T2 within each group by -2.13 (± 0.62) for MB group and - 2.46 (± 0.72) for TB group. No significant differences were found between both groups in SNA, SNB, ANB and Wits appraisal at p = 0.06, p = 0.45, p = 0.43 and p = 0.22 respectively. FMA did not show significant difference between T1 and T2 within each group, nor showed a significant mean difference between both groups at T2-T1. CONCLUSIONS: TB was more effective than MB in improving the upper (NPAA) and middle (OPAA) airways, while no difference was found regarding the lower airway (LPAA). Both TB and MB reduced the severity of developing skeletal class II due to mandibular retrognathism by forward posturing of the mandible. Thus, patients with airway problems would benefit more from TB than MB.

The effect of text message reminders on compliance with Twin Block appliances: A randomised controlled trial.

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 to wear their appliances every 3 days. 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 (P = 0.16). CONCLUSION: The study concluded that text message reminders had no statistically significant influence on patient compliance with Twin Block appliances.

The digital Twin Block appliance: Concept, design and fabrication.

The Twin Block appliance (TBA) has evolved over the decades to remain a very effective treatment for growing Class II patients. This article introduces how two new versions of the TBA may be produced through an entirely digital workflow, from intra-oral scanning to thermoplastic appliance fabrication, using a novel computer-aided design process.

The effect of treatment timing on clinical and psychological outcomes with Twin Block therapy: A multicentre two-arm parallel randomised controlled trial.

OBJECTIVE: To evaluate whether delaying treatment with a twin block appliance affects treatment outcomes, in terms of skeletal and dental change and psychological disadvantage. DESIGN: Multicentre, two-arm parallel randomised controlled trial. SETTING: Three UK hospital orthodontic units. METHODS: A total of 75 participants were randomly allocated into an Immediate Treatment Group (ITG) (n= 41) and an 18-month delayed Later Treatment Group (LTG) (n=34). OUTCOMES: Dentofacial changes were recorded from lateral cephalograms and study models, psychological impact was measured using a child perception questionnaire (CPQ11-14) and an Oral Aesthetic Subjective Impact Score (OASIS) at registration (DC1), 18 months (DC2) and 3 years (DC3). RESULTS: The ITG initial effect was a mean ANB reduction was 1.6° (P<0.001) (95% confidence interval [CI] = 0.89-2.29), and an overjet reduction of 5.06 mm (P<0.001) (95% CI = 3.96-6.16) (boys: aged 12 years 8 months; girls: aged 11 years 8 months). There were no statistically significant differences between the ITG and LTG for twin block treatment outcomes, but the ITG active treatment time was longer (P=0.004) (ITG: 13.1 months; LTG: 9.8 months). There was insufficient evidence to state that patients were psychologically disadvantaged by waiting 18 months for active twin block treatment (P>0.05). CONCLUSION: Participants achieved similar clinical and psychological outcomes irrespective of whether they started their twin block at the age of referral (ITG) or 18 months later (LTG). This suggests that boys aged 12 years 8 months and girls aged 11 years 8 months, on average, are not disadvantaged by waiting 18 months for active twin block treatment.

Comparative Evaluation of Twin Block Appliance and Fixed Orthodontic Appliance in Early Class II Malocclusion Treatment: A Randomized Controlled Trial.

AIMS: To compare skeletal, dentoalveolar, and soft tissue changes between Twin block and early fixed orthodontic appliance for class II division 1 malocclusion treatment through a randomized controlled trial. MATERIALS AND METHODS: Sample and randomization: This study was a randomized controlled trial with a 1:1 allocation ratio in which 40 patients were divided equally into two groups: control and experimental; each group had an equal number of boys and girls. Randomization was achieved using random blocks of 20 patients with allocation concealed in sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for data analysis of radiographic measurements. Intervention: Twin block appliance was used in the experimental group for 1 year. However, control group was treated with fixed appliance. Inclusion criteria: Skeletal class II division 1 malocclusion with mandibular retrognathism; cephalometric angular measurements: SNA ≥ 82, SNB ≤ 78, ANB ≥ 4; overjet ≥6 mm; and patient in circumpubertal stage cervical vertebral maturation (CVM2 and CVM3). Parameters for evaluation: Cephalometric skeletal, dental, and soft tissue angular and linear measurements were used for evaluation. RESULTS: SNB increased remarkably by 4° in the Twin block group, but only by 0.68 in the control group. There was a significant decrease in vertical dimensions (SN-GoGn) in the Twin block group compared to control group (p = 0.002). Significant enhancement in the facial profile of the patients was observed. CONCLUSIONS: The Twin block appliance induced significant skeletal and dental changes. These changes were more obvious relative to the slight changes induced by natural growth. CLINICAL SIGNIFICANCE: Early treatment of Class II due to mandibular retrusion with Twin block functional appliance is recommended due to its favourable skeletal effect. Early treatment with fixed appliance affects mainly the dentoalveolar component. Long term follow-up is needed for further insights.

Effect of Twin-block Appliance on Pharyngeal Airway, Sleep Patterns, and Lung Volume in Children with Class II Malocclusion.

AIM: In this study, we sought to evaluate the effect of the twin-block appliance on pharyngeal airway dimensions, sleep patterns, and lung volumes in growing children with class II malocclusion with a retrognathic mandible. MATERIALS AND METHODS: Twenty children aged 9-12 years with class II malocclusion with a retrognathic mandible participated in the study. A validated sleep questionnaire assessed the sleep patterns and the sleep problems of the children. The pre-treatment cephalometric variables and the pharyngeal airway passage (PAP) dimensions were analyzed. Spirometry tests were performed to evaluate lung volumes. A custom-made twin-block appliance was fabricated, and children were instructed to wear it for a minimum of 10 months. All variables including sleep problems, cephalometric variables, and pharyngeal airway measurements were evaluated post-treatment. Spirometry tests were re-evaluated at the end of the twin-block treatment. All data were statistically analyzed. RESULTS: Post-twin-block appliance treatment, there was a definite decrease in snoring, noisy breathing, and sleeping with mouth open. The sella-nasion to B point angle (SNB), mandibular length, the depths of oropharynx, nasopharynx, and hypopharynx as well as the height of nasopharynx (HNP) were significantly increased post-treatment (p <0.001). The length and thickness of soft palate (SPI) increased significantly (p <0.001), while its inclination decreased significantly (p <0.001). We found improvements in forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1); however, the changes were statistically not significant (p = 0.88 and p = 0.78). CONCLUSION: Twin-block appliance significantly increased the pharyngeal airway dimensions and improved the length and thickness of the soft palate in children with class II malocclusion. Post-twin-block treatment showed a considerable reduction in the sleep problems of the children. The lung volume measurements showed improvement; however, it was not statistically significant. CLINICAL SIGNIFICANCE: Twin block may be used not only to correct the facial disharmony of children with a retrognathic mandible but also to improve the airway dimensions and lung volume as well as to reduce the sleep-disordered symptoms.

Class II Division 1 Adolescent Treatment with Twin Block and Fixed Orthodontic Appliances: 3-Dimensional Changes of the Temporomandibular Joint.

INTRODUCTION: Skeletal Class II division 1 malocclusions with a retrognathic mandible can be treated with Twin Block and fixed orthodontic appliances in growing adolescent patients. OBJECTIVE: The aim of this case report was to show successful treatment results following step-by-step procedures determined by visualizing the changes of the temporomandibular joint (TMJ) area using cone-beam computed tomography (CBCT) images. CASE REPORT: A 10-year, 8-month-old female adolescent with skeletal Class II division 1 (ANB, 6.2°), severe overjet (8.4 mm), and overbite (7.8 mm) was treated with Twin Block and fixed orthodontic appliances. After wearing an active plate for 4 months, a Twin Block appliance for 9 months, a retainer with an inclined plane for 13 months, and fixed orthodontic treatment for 17 months, her skeletal Class II was corrected. After 39 months of posttreatment retention, good treatment results were maintained with favorable occlusion and facial balance. Acceptable 3-dimensional changes of the TMJ area were identified using cone-beam computed tomography images. CONCLUSION: A female adolescent patient with skeletal Class II division 1 malocclusion, severe overjet and overbite, and mandibular retrusion was treated using Twin Block and fixed orthodontic appliances. Acceptable 3-dimensional changes in the TMJ area and 2-dimensional growth of the mandible were identified using CBCT and cephalometric images.

Evaluation and quantification of airway changes in Class II division 1 patients undergoing myofunctional therapy using twin block appliance.

BACKGROUND: The purpose of the present study was to determine the airway changes in skeletal class II division 1 malocclusion patients with mandibular retrognathism, treated with Twin-Block (TB) appliance. METHODS: Airway assessment was carried for twelve patients (mean age 11.7 ± 1.1 years) who underwent myofunctional therapy using TB appliance for correction of skeletal class II division 1 malocclusion with mandibular retrognathism. Acoustic pharyngometry (AP) was used to assess and quantify the comparative changes in the upper airway, pretreatment and posttreatment. RESULTS: Data acquired was subjected to appropriate statistical analysis. The paired 't' test was used to compare pre-treatment (T0) and after the positive pterygoid response (T1). TB appliance increased mean minimum airway area by 0.28 ± 0.25 cm2 and mean airway by 0.47 ± 0.44 cm2 with 95% CI. Posttreatment minimum airway and mean area changes were found to be statistically significant (P-value<0.01). CONCLUSION: TB appliance therapy has a positive effect on upper airway and is beneficial for the treatment of sleep-related disorders associated with Class II division 1 malocclusion for achieving positive functional changes, esthetics, and healthier quality of life.

Comparison of the effects of rapid maxillary expansion versus Twin Block appliance on mandibular growth in skeletal Class II patients.

BACKGROUND: This is a retrospective study that compares mandibular growth changes in skeletal Class II patients treated by rapid maxillary expansion (RME) and following fixed appliance with those patients treated by Twin-Block (TB) and following fixed appliance. METHODS: Fourteen patients treated by RME and following fixed appliance were included into the RME group. Fifteen patients treated by Twin-Block and following fixed appliance were included into the TB group. Lateral cephalometric radiographs taken before treatment and immediately after fixed appliance treatment were used to evaluate mandibular growth effects. RESULTS: The starting forms of the patients in the two groups were examined to be of good comparability. The mandibular length increased significantly in both groups as measured by Co-Gn, Go-Gn and Ar-Gn, but the TB group didn't show more mandibular growth than the RME group (P > 0.05). Skeletal changes of the mandible in vertical dimension were different in the two groups. The change in FMA was 0.35° in the RME group, while the change was 2.65° in the TB group (P < 0.001). The change in LAFH was 5.14 mm in the RME group, significantly smaller than the change of 10.19 mm in the TB group (P < 0.001). CONCLUSION: The investigated Phase I treatment with RME followed by Phase II treatment of fixed appliance achieved the same increases in sagittal mandibular growth and facial profile improvements as the Twin-Block therapy. The treatment with RME followed by fixed appliance was better for vertical control, while the treatment with Twin-Block followed by fixed appliance significantly increased the mandibular plane angle.

[Creating the conditions for skeletal traction in mandibular condyle fracture in children and adolescents]. / Sozdanie uslovii skeletnogo vytyazheniya pri perelome myshchelkovogo otrostka nizhnei chelyusti u detei i podrostkov.

In this article the possibility of using the Clark appliance (Twin-block) for creating conditions for skeletal traction in case of fraction of mandibular condyle in children and teenagers is presented. The proposed method of using the double-jaw orthodontic appliance Twin-block in case of mandibular fractures with condylar displacement promotes release of traumatized condyle and mandible replacement to correct position, promotes optimal conditions for myofunctional balance, fragment consolidation and remodeling of affected temporomandibular joint.