Modified Twin Block Appliance Research Articles

Effects of modified twin block appliance in growing Class II high angle cases: A cephalometric study

Background Class II malocclusions represent anteroposterior dysplasia usually resulting from mandibular retrusion. Along with a retropositioned mandible, it can be associated with either upward or backward jaw rotation. High angle cases are often associated with a short ramal height, steeper mandibular plane, and large gonial angle. Twin block is a commonly used myofunctional appliance that incorporates bite planes that direct the occlusal forces in a more favorable direction for correction of the retrognathic mandible. We aimed to evaluate skeletal, dental, and soft tissue changes following modified twin block appliance therapy in high-angle cases. Methods A cephalometric study was performed on 15 growing (10-14 years) high angle (Frankfort mandibular angle 28-35°) Class II Division I malocclusion patients undergoing twin block therapy. Skeletal, dental, and soft tissue changes were evaluated by cephalometric analysis using Dolphin software. Results Pre- and post-treatment changes in cephalograms were assessed by analysis of variance and paired t-test. Significant changes in the position of the mandible (angle between Sella-Nasion-Point B [SNB] increased by 3.9 degrees, P=0.02), Wits appraisal (decreased by 1.54 mm, P=0.04), maxillo-mandibular relationship (angle between Point A-Nasion-Point B [ANB] decreased by 3.74 degrees, P=0.02) were observed. Soft tissue changes like the nasolabial angle were also significant, increasing by 3.8 degrees (P=0.04) and lower lip relation to E-line (reduction in lower lip protrusion) by 2 mm (P=0.04). Vertical parameters showed non-significant changes, like the Frankfort mandibular angle (FMA) increased by 0.07 degrees, (P=0.67), the angle between Sella-Nasion and Gonion-Gnathion (SN-Go-Gn) increased by 0.33 degrees, (P=0.67), Y-axis increased by 0.2 degrees, (P=0.32). The upper incisor inclination decreased non-significantly from 115.27±1.33 to 113.42±1.65 degrees, (P=0.12) and lower incisor increased non-significantly from 100.13±2.23 to 101.80 ±1.37 degrees, (P=0.08). Conclusions Modified twin block appliance can be used to successfully treat Class II Division I high angle cases with good vertical control.

Palatal Morphology After Treatment of Children With Obstructive Sleep Apnoea Using the Modified Twin-Block Appliance

ObjectiveTo investigate changes in the upper maxillary palates of children with obstructive sleep apnoea (OSA) and mandibular retraction who were treated using modified twin-block appliances (MTBAs). MethodsThirty-five OSA children (age: 6-12 years) with mandibular retraction were included as the experimental group and 35 children who were Angle's class I but without mandibular retraction were included as the control group. The experimental group was treated with MTBA. Plaster models were made before the treatment and at the end of the 6-month treatment period. Plaster models of the control group were made at inclusion and after 6 months. Some plaster models were excluded because of damage or their failure to exhibit sufficiently clear marks, which left 26 pairs each for the experimental and control groups. The gender and age of the experimental group were matched with those of the control group at the end of the treatment. Three-dimensional (3D) digital model information was gathered using the external oral scanning model, and the data were extracted and analysed statistically to clarify the morphologic improvement in the maxillopalatine in OSA children treated using MTBAs. ResultsAfter the OSA children with mandibular retraction were treated with MTBAs, the maxillary intercusp width, intermolar width, anterior palate width, posterior palate width, and surface area and volume of the maxillary palate significantly increased (*P < .05). By contrast, the anterior palatal height–apex level (H3) significantly decreased (*P < .05). ConclusionsCompared with the control group, the narrow maxillary arch and basal bone were significantly enlarged after the OSA children with mandibular retraction were treated using MTBAs. The palatal surface area and volume increased, thereby allowing more space for accommodating the tongue and relieving transverse dissonance of the dentition.

Efficacy of a modified twin block appliance compared with the traditional twin block appliance in children with hyperdivergent mandibular retrognathia: protocol for a single-centre, single-blind, randomised controlled trial

IntroductionCompensatory mouth breathing, caused by nasopharyngeal obstructive diseases, is the main cause of hyperdivergent mandibular retrognathia in children. Such deformities require effective growth guidance before pubertal growth peaks. The traditional...

Effects of modified twin block appliance in growing Class II high angle cases: A cephalometric study.

Class II malocclusions represent anteroposterior dysplasia usually resulting from mandibular retrusion. Along with a retropositioned mandible, it can be associated with either upward or backward jaw rotation. High angle cases are often associated with a short ramal height, steeper mandibular plane, and large gonial angle. Twin block is a commonly used myofunctional appliance that incorporates bite planes that direct the occlusal forces in a more favorable direction for correction of the retrognathic mandible. We aimed to evaluate skeletal, dental, and soft tissue changes following modified twin block appliance therapy in high-angle cases. A cephalometric study was performed on 15 growing (10-14 years) high angle (Frankfort mandibular angle 28-35°) Class II Division I malocclusion patients undergoing twin block therapy. Skeletal, dental, and soft tissue changes were evaluated by cephalometric analysis using Dolphin software. Pre- and post-treatment changes in cephalograms were assessed by analysis of variance and paired t-test. Significant changes in the position of the mandible (angle between Sella-Nasion-Point B [SNB] increased by 3.9 degrees, P=0.02), Wits appraisal (decreased by 1.54 mm, P=0.04), maxillo-mandibular relationship (angle between Point A-Nasion-Point B [ANB] decreased by 3.74 degrees, P=0.02) were observed. Soft tissue changes like the nasolabial angle were also significant, increasing by 3.8 degrees (P=0.04) and lower lip relation to E-line (reduction in lower lip protrusion) by 2 mm (P=0.04). Vertical parameters showed non-significant changes, like the Frankfort mandibular angle (FMA) increased by 0.07 degrees, (P=0.67), the angle between Sella-Nasion and Gonion-Gnathion (SN-Go-Gn) increased by 0.33 degrees, (P=0.67), Y-axis increased by 0.2 degrees, (P=0.32). The upper incisor inclination decreased non-significantly from 115.27±1.33 to 113.42±1.65 degrees, (P=0.12) and lower incisor increased non-significantly from 100.13±2.23 to 101.80 ±1.37 degrees, (P=0.08). Modified twin block appliance can be used to successfully treat Class II Division I high angle cases with good vertical control.

Evaluation of the physical properties of a novel twin block appliance in treatment of skeletal class II growing females with mandibular deficiency

Objective: This study was performed to reveal the physical changes of polymers used after gamma irradiation of a modified twin block appliance versus conventional twin block appliance in the treatment of growing females with skeletal Class II malocclusion having mandibular deficiency. Materials and methods: The total sample consisted of 12 specimens 6 from every polymer, modified twin block group which was composed of polyethylene polymer and conventional twin block group which was formed of poly methyl-methacrylate polymer used in this study, exposed to different gamma irradiation doses (25 KGray and 30 KGray) in order to test their physical properties. Assessment was done using UV-visible spectroscopy and scanning electron microscope. Results: This study revealed that concerning the gamma radiation effect on the polymers used, Poly methyl methacrylate showed yellowish color change and increased number of pores on its surface after irradiation while polyethylene vacuum sheets didn’t show any color change but the scratches and pores appeared on its surface using scanning electron microscope. Conclusion: From the previous results it can be concluded that the modified twin block appliance can be used as an alternative orthopedic appliance in treatment of skeletal class II malocclusion growing subjects with mandibular retrusion.

Effects of modified twin block appliance in growing Class II high angle cases: A cephalometric study

Background: Class II malocclusions represent anteroposterior dysplasia usually resulting from mandibular retrusion. Along with a retropositioned mandible, it can be associated with either upward or backward jaw rotation. High angle cases are often associated with a short ramal height, steeper mandibular plane, and large gonial angle. Twin block is a commonly used myofunctional appliance that incorporates bite planes that direct the occlusal forces in a more favorable direction for correction of the retrognathic mandible. We aimed to evaluate skeletal, dental, and soft tissue changes following modified twin block appliance therapy in high-angle cases. Methods: A cephalometric study was performed on 15 growing (10-14 years) high angle (Frankfort mandibular angle 28-35°) Class II Division I malocclusion patients undergoing twin block therapy. Skeletal, dental, and soft tissue changes were evaluated by cephalometric analysis using Dolphin software. Results: Pre- and post-treatment changes in cephalograms were assessed by analysis of variance and paired t-test. Significant changes in the position of the mandible (angle between Sella-Nasion-Point B [SNB] increased by 3.9 degrees, P=0.02), Wits appraisal (decreased by 2.46 mm, P=0.04), maxillo-mandibular relationship (angle between Point A-Nasion-Point B [ANB] decreased by 3.73 degrees, P=0.02) were observed. Soft tissue changes like the nasolabial angle were also significant, increasing by 3.8 degrees (P=0.04) and lower lip relation to E-line (reduction in lower lip protrusion) by 2 mm (P=0.04). Vertical parameters showed non-significant changes, like the Frankfort mandibular angle (FMA) increased by 0.07 degrees, (P=0.67), the angle between Sella-Nasion and Gonion-Gnathion (SN-Go-Gn) increased by 0.33 degrees, (P=0.67), Y-axis increased by 0.2 degrees, (P=0.32). The upper incisor inclination decreased non-significantly from 5.60±1.24 to 4.20±0.86 degrees, (P=0.31) and lower incisor increased non-significantly from 100.13±2.23 to 101.80 ±1.37 degrees, (P=0.08). Conclusions: Modified twin block appliance can be used to successfully treat Class II Division I high angle cases with good vertical control.

Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study.

ABSTRACTAimAchieving a satisfactory facial esthetics is of utmost importance in the practice of orthodontics. Cl II div 1 patients often suffer from numerous adverse facial characteristics which may impair their social well-being. The objective of the current study was to evaluate the esthetic changes in such patients by using a modified twin block appliance.Materials and methodsSeventy adolescent patients with mandibular deficiency consecutively underwent treatment with a modified twin block appliance for a mean period of 13 months. Soft tissue analyzes of Burstone and Mcnamara were applied to evaluate the changes before and after the treatment. The esthetic changes before and after the therapy were compared using parametric paired t tests analysis. p values less than 0.05 were considered significant.ResultsFacial convexity, lip incompetence, upper lip protrusion, and columellar inclination significantly decreased (p < 0.05) while Merrifield's Z-angle nasolabial angle, lower lip length, and mentolabial angle significantly increased (p < 0.05). Vertical facial height ratio, lower lip protrusion, upper lip length as well as nasal projection and inclination, did not change significantly (p > 0.05)ConclusionOur findings indicated that a modified form of the twin block appliance can be substantially effective in the improvement of several aspects of patients’ facial balance with minimum untoward effects.Clinical significanceAdolescents suffering from mandibular deficiency can gain substantial facial balance with the twin block appliance. The whole face attractiveness, however, is another subject and should not be conflicted with the facial balance.How to cite this articleShahamfar M, Atashi MHA, Azima N. Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study. Int J Clin Pediatr Dent 2020;13(3):255–260.

Frankel 2 appliance versus the Modified Twin Block appliance for Phase 1 treatment of Class II division 1 malocclusion in children and adolescents: A randomized clinical trial.

To compare Phase 1 treatment, using the Frankel 2 (FR2) or the modified Twin Block (MTB), for Class II division 1 malocclusion in children and adolescents with respect to: treatment duration, number of appliance breakages, occlusal outcome, and patient and parent perspectives. Sixty participants with a Class II division 1 malocclusion were randomly assigned to either the FR2 or MTB appliance in a two-armed parallel randomized clinical trial with an allocation ratio of 1 to 1. Time to achieve a Class I incisor relationship was the primary outcome. The number of appliance breakages was recorded. The Peer Assessment Rating (PAR) index was used to evaluate pre- and post-treatment occlusal outcome on study models. Participants completed the child OHRQoL (oral health-related quality of life), Piers-Harris, Standard Continuum of Aesthetic Need (SCAN), and Oral Aesthetic Subjective Impact Score (OASIS) questionnaires pre- and post-treatment; parents completed a SCAN questionnaire. Forty-two participants completed treatment (FR2: 20; MTB: 22). Multiple imputation was used to impute missing data for noncompleters. Mean treatment duration was similar for the two appliances (FR2: 376 days [SD 101]; MTB: 340 days [SD 102]; P = .41). There were no significant differences in mean number of appliance breakages (FR2: 0.3 SD 0.7; MTB: 0.4 SD 0.8; P = .67 or mean PAR score P = .48). Patient and parent perspectives did not differ between appliances (P > .05). Phase 1 treatment duration, number of appliance breakages, occlusal outcome, and patient and parent perspectives were similar in 11-14 year olds with Class II division 1 malocclusion treated using the FR2 or MTB appliance.

Dentoskeletal effects of class II malocclusion treatment with the modified Twin Block appliance.

BackgroundThe purpose of this study was to prospectively assess the dentoskeletal effect of a modified Twin Block appliance for treatment of class II malocclusions.Material and MethodsLateral cephalograms of 25 Class II malocclusion patients were compared to evaluate skeletal, dentoalveolar and soft tissue changes pre- and post-treatment with a modified Twin Block appliance. A total of 33 angular and linear variables were used for analysis. The differences were calculated at the start and end of treatment. The paired T test was performed to compare the cephalometric measurements before and after treatment.ResultsCompared the pre- and post- treatment measurements, there was a significant increase in SNB (P<0.001), CO-Gn (P<0.001), ANS-Me (P=0.001), Mandibular base (P<0.001), Lower 1 to NB (°) (P=0.004), Lower 1 to NB (mm) (P<0.001), and Z-angle (P=0.001) following functional therapy with modified Twin Block appliance. On the other hand, a significant decrease was observed in ANB (P<0.001), NA-Pog (P<0.001), overjet (P<0.001), and overbite (P=0.007), Upper 1 to palatal plane (P=0.007), UL-E-line (P<0.001), LL-E-line (P=0.001), and H-angle (P=0.002) after treatment with modified Twin Block appliance.ConclusionsThe modified Twin-Block improves facial esthetics in Class II malocclusion by a combination of changes in skeletal as well as dentoalveolar structures. The increase of mandibular unit length was observed to be due to a true mandibular growth not just a repositioning of the mandible. The modified appliance, however, did not show any superior effects in terms of less dental compensation compared to the conventional Twin–Block appliance. Key words:Dentoskeletal effect, Modified Twin Block, Class II malocclusion.

Effect of modified twin block appliance used for distoclusion treatment on stomatognathic system

Aim. Study of the effect of modified twin block activator used for distoclusion treatment on stomatognathic system and its improvement. Methods. 55 patients with skeletal distoclusion were examined. Out of them 28 patients treated orthodontically comprised the study group and 27 non-treated patients were included into the control group. The patients' age was 10-14 years (mean age 11.78±0.91), the duration of treatment was 1.5-2 years (mean duration 1.82±0.43). To avaluate the changes in stomatognathic system, cephalometric analysis was performed before and after treatment, and in the control group cephalometric analysis was performed with a 2-year interval. Results. During treatment with modified twin block appliance, SNB angle reached norm (80°). This is an important positive result in the treatment of distoclusion. ANB angle reflecting sagittal relationship between the upper and lower jaws and WITS decreased and reached normal size. Overjet normalized due to upper incisors retrusion and repositioning of the mandible forward in patients of the study group. In this group due to changes in soft tissues, in-profile esthetic and harmonious appearance of lips and chin was restored. In case of relative physiological rest the opened lips became closer and provided esthetic optimum of the face. Conclusion. Use of modified twin block appliance for the treatment of patients with distoclusion due to repositioning of the mandible forward allows improving sagittal relationship between the upper and lower jaws as well as overjet correction without increasing face height; use of modified twin block appliance allows normalizing sagittal occlusion and protrusion of upper incisors and upper lip.

Soft tissue changes: a comparison between changes caused by the construction bite and by successful treatment with a modified Twin-block appliance.

Functional appliances are commonly used to correct Class II malocclusion. This study aimed to compare the facial soft tissue changes in Caucasians between pre-treatment and with the construction bite versus pre-treatment and completion of treatment with a modified Twin-block appliance (MTBA). Fifty-eight Caucasian subjects with Class II division 1 malocclusion had 3D stereophotogrammetric images captured pre-treatment (T1), with the construction bite (T2), and on completion of MTBA treatment (T3). Twenty-six landmarks were located on each image and 10% were re-landmarked 1 month later. Soft-tissue linear and volumetric changes (T1-T2 and T1-T3) were analyzed using linear mixed effect models (SAS® Version 9.4, www.sas.com). Forty-seven subjects [mean age 13.2 (SD 1.7) years] completed treatment [mean duration 9.8 (SD 3.8) months]. Differences between the changes from T1 to T2 versus T1 to T3 for upper facial and upper lip landmarks were insignificant (all P > 0.05) except for nasion, orbitale right, pronasale, and subnasale. For the same comparisons, lower lip and chin landmarks changed significantly (all P < 0.05) as did facial soft tissue volume (P< 0.0001). There was no control group. The facial soft tissue changes from pre-treatment to with the construction bite were considerably more than those from pre-treatment to completion of treatment with a MTBA. With MTBA treatment, the soft tissue changes from pre-treatment to with the construction bite in situ, overestimate those from pre- to post-treatment.

Early Treatment of Class II Division 1 malocclusion by Modified Twin Block Appliance

Early Treatment of Class II Division 1 malocclusion by Modified Twin Block Appliance

Treatment effects of the twin block appliance: A cephalometric study

A clinical study was undertaken to investigate the treatment effects of a modified Twin Block appliance. Pretreatment and posttreatment cephalometric records of 28 consecutively treated patients with Class II malocclusions were evaluated and compared with an age- and sex-matched sample of untreated Class II control subjects. The treatment group was considered to have severe skeletal Class II malocclusions and was treated using only the Twin Block appliance. Results indicated that mandibular growth in the treatment group was on average 4.2 mm greater than in the control group over the 14-month treatment period. In addition, some dentoalveolar effects in both arches contributed to the overjet correction. No statistically significant increase in the SN-mandibular plane angle occurred during treatment and, in general, the magnitude and direction of the skeletal changes were found to be quite favorable. (Am J Orthod Dentofacial Orthop 1998;114:15-24)