A randomized clinical trial to assess the sagittal effects of Transforce transverse appliance (TTA) and NiTi palatal expander (NPE) on skeletal class II malocclusion in growing patients during retention phase - A cephalometric study using a historical control group.

OBJECTIVES: To evaluate and compare the skeletal changes during the retention period after expansion with "Transforce Transverse lingual or palatal Appliance®" (TTA) and "NiTi Palatal Expander®" (NPE) in growing subjects with class II division 1 malocclusion and to compare these changes with a matched historical control. SUBJECTS AND METHODS: A unicentric two arm, parallel randomized clinical trial with additional historical control group was conducted over a period of six years. The subjects in the age group of 9-13 years were screened and recruited as they reported. The inclusion criteria were: late mixed/early permanent dentition, class II or end on molar relationship, posterior transverse inter-arch discrepancy 4-8mm, overjet≥5mm, cephalometrically ANB>4° and CVMI stage CS2-CS3. Subjects were randomly allocated to two study groups (SG), TTA and NPE using block randomization. Appliances in both SG were managed and followed by a single clinician with equal standards of care. The lateral cephalograms in digital form were obtained at the beginning of the treatment (T1), post-expansion (T2) and after ten months retention period (T3). Linear positional change>1mm and angular change>0.75° were considered as a clinically significant change. Due to the ethical reasons a historical control of ten patients (CG) comparable to the SG for age and inclusion criteria was used to rule out the growth changes on serial lateral cephalograms. All Cephalometric measurements were done by a single operator blinded for the group allocation. Operator's measurement error was estimated. The study was single-blinded in regard to statistical analysis. Inter-group comparisons between SG were made by using an unpaired Student's t-test. ANOVA with post-hoc analysis was used for comparison among the study and control groups. RESULTS: A total of 36 subjects were recruited, 18 in each SG. Average time required to achieve the desired expansion in the TTA and NPE group was 13.6 weeks and 9.8 weeks respectively. The TTA group showed significant increase in SNB (1.54±0.33°) when compared with the control group (0.53±0.37°) and with the NPE group (0.74±0.29°) (P<0.0001). Significant differences were observed when post-retention changes in SNB, ANB, Wits appraisal, and N perpendicular to Pogonion, were compared among the three groups (ANOVA, P<0.0001). Tukey's multiple comparison showed that these mandibular sagittal changes were significantly greater in the TTA group than in NPE and the control group (P=<0.007, Bonferroni corrected value). CONCLUSION: Cephalometrically significant sagittal advancement of mandible took place after expansion with TTA and NPE compared to untreated control. TTA appears to be more efficient for the sagittal positional changes than the NPE. Additional studies with larger samples are warranted to elucidate individual variations in skeletal response to the expansion protocol with these appliances.

Effectiveness of reverse twin block with lip pads-RME and face mask with RME in the early treatment of class III malocclusion.

BACKGROUND: The use of face mask for early treatment of class III malocclusion has proven to be successful, but its compliance and related dental side effects have always been a problem. To overcome this, a new approach has been suggested. The purpose of the present study was to compare the effectiveness of reverse twin block with lip pads and fixed rapid maxillary expansion (RTBLP-RME) appliance and face mask with RME (FM-RME) appliance for early treatment of class III malocclusion. METHODS: The sample consisted of 39 patients with class III malocclusion in the age group of 6-12 years (mean 10.17). They were divided into 3 groups of 13 each: reverse twin block with lip pads-RME (RTBLP-RME), face mask with RME (FM-RME), and control group. Treatment time was 9 months. Lateral cephalograms were taken at the start of treatment (T1) and after 9 months (T2) (both groups). RESULTS: Both appliances were effective in correction of class III malocclusion with significant (p < 0.01) changes in all the cephalometric variables except cranial base angulations as compared to the control group. Intergroup comparison showed nonsignificant but greater sagittal changes with RTBLP-RME as compared to the FM-RME group. For all vertical measurements, the RTBLP-RME group showed nonsignificant increase compared to the FM-RME group. Maxillary incisor proclination was less in the RTBLP-RME group than in the FM-RME group, while mandibular incisor proclination was more in the RTBLP-RME group. Condylar inclination was significantly (p < 0.01) different for both treatment groups. With the RTBLP-RME group, posterior inclination of the condyle was seen while the FM-RME group showed more forward positioning as compared to the control group. CONCLUSION: Both groups were effective in correcting the malocclusion, but RTBLP-RME appliance had nonsignificant but greater impact on maxillary advancement and more hold on the posterior positioning of the mandible with minimal dental compensation as compared to FM-RME appliance.

Early correction of unilateral scissor bite using transforce appliance and modified twin block appliance.

Early treatment of scissor bite has been advocated mainly to prevent function jaw shift that can eventually lead to permanent skeletal asymmetry and temporomandibular joint pathosis. Although unilateral scissor bite is more common, most of the times, bilateral mandibular expansion is indicated. Lingual transforce appliance can be useful in such cases. This article presents a patient with unilateral scissor bite in mixed dentition with alveolar narrowing. Transforce appliance was used for scissor bite correction followed by modified twin block appliance for stabilization and settling of occlusion till the eruption of premolars. The case was finished with fixed mechanotherapy. Two years after completion of treatment, results were well maintained. Our results suggest that lingual transforce appliance along with careful management of occlusion is effective in the early management of severe unilateral scissor bite.

Comparison of temporomandibular joint changes in Twin Block and Bionator appliance therapy: a magnetic resonance imaging study.

BACKGROUND: The objective of the present study was to evaluate and compare temporomandibular joint changes especially disk-condyle-fossa relationship following functional treatment of skeletal class II division 1 malocclusion using Twin Block and Bionator appliances. METHODS: The total sample consisted of 30 subjects (13 males and 17 females) with class II division 1 malocclusion having mandibular retrognathism, in the age group of 9 to 14 years. Two treatment groups, i.e., Twin Block and Bionator groups, were formed which comprised ten subjects each, while a group of ten subjects served as the control group. The treatment effects were evaluated using magnetic resonance imaging (MRI). For the treatment groups, pretreatment MRI with wax construction bite was taken. For all subjects, MRI images with corrected sagittal T1 images were recorded in a maximal intercuspation position at pretreatment (R1) and in an unstrained retruded position at the end of a 6-month observation period (R2). RESULTS: At the end of 6 months of treatment, the condyles occupied a more anterior position in the fossa to its pretreatment position, while the disk moved more posteriorly in relation to the condyle. The control group showed no changes in the condyle and disk position over a period of 6 months. CONCLUSIONS: Although the treatment group showed consistent forward positioning of the condyle and backward movement of the disk, long-term MRI findings in these groups will further clarify the adaptations between the condyle fossa and articular disk.

A new approach of assessing sagittal dysplasia: the W angle.

In orthodontic diagnosis and treatment planning, an accurate antero-posterior measurement of jaw relationships is critically important. Previously described angular and linear measurements can be inaccurate because of their dependency on various factors. The purpose of this study was to introduce a new cephalometric measurement, named the W angle, to assess the sagittal relationship between maxilla and mandible with accuracy and reproducibility. This angle uses three skeletal landmarks--point S, point M, and point G--to measure an angle that indicates the severity and the type of skeletal dysplasia in the sagittal dimension. One hundred and forty-two pre-treatment cephalometric radiographs of patients between the age of 15 and 25 years were selected. They were again subdivided into Classes I, II, and III groups on the basis of Beta angle, Wits appraisal, and ANB angle. The W angle was measured between the perpendicular from point M on S-G line and the M-G line. The mean and the standard deviation for the W angle were calculated. After using the one-way analysis of variance and the Newman-Keuls test, receiver operating characteristics curves were obtained. Results showed that a patient with a W angle between 51 and 56 degrees can be considered to have a Class I skeletal pattern. With an angle less than 51 degrees, patients are considered to have a skeletal Class II relationship and with an angle greater than 56 degrees, patients have a skeletal Class III relationship.

Comparison of sagittal anchorage conservation of mini-implants and modified Nance palatal buttons.

OBJECTIVE: To compare the anchorage potential of mini-implants with modified Nance palatal buttons during simultaneous first and second maxillary molar distalization. METHODS: Mini-implants (1.4 x 10 mm) placed to obtain indirect anchorage for maxillary molar distalization using a superelastic Ni-Ti open coil spring were compared with anchorage derived from a modified Nance palatal button incorporated in a distal jet appliance. Appliances were placed bilaterally in 19 adolescent patients. Lateral cephalograms with guide wires to differentiate the right from left sides were used for evaluation. All measurements (angular and linear) were obtained from these guide wires. RESULTS: Anchorage loss at the first premolar was 13% with mini-implant-supported Ni-Ti coil spring appliances and 24.75% with the Nance palatal button (distal jet appliance) on the right side. On the left side, anchorage loss was 15.4% with mini-implant-supported Ni-Ti coil spring appliances and 23.9% with the Nance palatal button (distal jet appliance). CONCLUSION: Mini-implants do not provide absolute anchorage when used indirectly. However, anchorage conservation is more efficient than modified Nance palatal buttons.

Spring-loaded bite-blocks for early correction of skeletal open bite associated with thumb sucking.

Skeletal open-bite malocclusion is frequently discussed in orthodontics. Diagnosis, treatment, and retention can be difficult because this malocclusion has numerous correlated etiologic factors. The earlier this malocclusion is corrected, the better the prognosis will be, especially when the problem is skeletal. This article presents a patient with a skeletal open bite and a thumb-sucking habit who was treated in the mixed dentition with an orthodontic appliance that included an acrylic occlusal splint along with spring-loaded blocks to guide the vertical force against the posterior teeth and the alveolar process. The usefulness of the appliance as a habit-breaking therapy is also highlighted.

Static frictional force and surface roughness of various bracket and wire combinations.

INTRODUCTION: During sliding mechanics, frictional resistance is an important counterforce to orthodontic tooth movement, which must be controlled to allow application of light, continuous forces. We investigated the static frictional resistance between 3 modern orthodontic brackets-ceramic with gold-palladium slot, ceramic, and stainless steel-and 4 archwires (0.019 × 0.025-in)-stainless steel, nickel-titanium, titanium-molybdenum alloy (TMA), and low-friction colored TMA. METHODS: All tests were carried out in a dry state on a universal testing machine. Surface topography of bracket slots and archwires was studied by using a scanning electron microscope and quantified by using a surface roughness testing machine (profilometer). RESULTS: In the scanning electron microscope measurements, the smoothest surface was the ceramic gold-palladium bracket and stainless steel wire. The profilometer quantified the surface roughness, which also was lowest for the ceramic gold-palladium bracket and stainless steel wire. The ceramic bracket with the gold-palladium slot showed the least frictional values in all combinations and could be a promising alternative to solve the problem of friction. Frictional values for colored TMA were comparable with stainless steel wires and might be a good alternative during space closure in sliding mechanics. CONCLUSIONS: Ceramic with gold-palladium slot bracket and colored TMA archwire seem to be a good alternative to stainless steel in space closure with sliding mechanics.

Early management of skeletal open bite with spring-loaded and magnetic bite blocks.

The purpose of this study was to evaluate the effects of spring-loaded and magnetic bite blocks in growing individuals with skeletal open bites. The sample consisted of patients between 8 and 13 years of age randomly divided into two groups. One group was treated with spring-loaded bite blocks while the other received treatment with magnetic bite blocks. Further, a group matched for age, sex, and mandibular plane angle served as a control. The treatment effects were evaluated clinically and cephalometrically and by electromyographic (EMG) examination of the masseter and temporalis muscles after 8 months. Both appliances showed significantly (P<.05) favorable orthopedic effects. The spring-loaded bite blocks closed the existing open bite by 3.3 mm on average with a significant maxillary incisor extrusion and molar intrusion. Magnetic bite blocks produced an average of 4.9 mm of open bite closure with significant intrusion of the molars in both arches. Overall, both appliances significantly enhanced condylar growth, altered it to a more anterosuperior direction, and produced significant true forward mandibular rotation. Significant increases in masseter and temporalis muscle activity at rest and maximum clenching were noted in both groups, which could be a positive factor in retaining the achieved result. After 10 months of retention with passive bite blocks, cephalograms indicated only an insignificant relapse.