Distal Movement Research Articles

Clinical Evaluation of Bone-Anchored Intraoral Bodily Molar Distalizer

Introduction: Correction of Class II has become a routine with the introduction of mini-implants. Objective: The objective of the study was to evaluate the clinical efficiency of bone-anchored intraoral bodily molar distalizer (BAIBMD) as compared to bone-anchored pendulum appliance (BAPA). Materials and Methods: This split-mouth study included 11 subjects (6 boys and 5 girls) who required molar distalization. BAPA constructed on one side and BAIBMD on the other side. Both the appliances were anchored to the bone, using a single 2 × 8 mm titanium mini-screw placed in the anterior para-median region of the mid-palatal suture with its head embedded into the Nance button during construction. The force delivery mechanism on both the sides consisted of 200 g-force application, using an activated 0.032˝ titanium molybdenum alloy (TMA)[A]:Author: Please provide expansion for “TMA.” springs fabricated with respective designs and inserted into the lingual sheaths of the first molar bands. The rate, duration, and nature of tooth movement for both the sides were compared. Descriptive statistics for various parameters were analyzed using Wilcoxon signed-rank test. Results: Clinically successful distalization was achieved on both sides. No statistical difference was found in the rate of distalization. Differences in the treatment duration between the two groups were statistically significant, with less duration taken for distalization with BAPA. Statistically significant molar tipping was observed in BAPA. Conclusion: While both the appliances provided a similar rate of distalization, BAIBMD took more duration than BAPA but produced a predominantly translatory type of distal tooth movement.

Biomechanical analysis of occlusal modes on the periodontal ligament while orthodontic force applied.

The study objective was to investigate four common occlusal modes by using the finite element (FE) method and to conduct a biomechanical analysis of the periodontal ligament (PDL) and surrounding bone when orthodontic force is applied. A complete mandibular FE model including teeth and the PDL was established on the basis of cone-beam computed tomography images of an artificial mandible. In the FE model, the left and right mandibular first premolars were not modeled because both canines required distal movement. In addition, four occlusal modes were simulated: incisal clench (INC), intercuspal position (ICP), right unilateral molar clench (RMOL), and right group function (RGF). The effects of these four occlusal modes on the von Mises stress and strain of the canine PDLs and bone were analyzed. Occlusal mode strongly influenced the distribution and value of von Mises strain in the canine PDLs. The maximum von Mises strain values on the canine PDLs were 0.396, 1.811, 0.398, and 1.121 for INC, ICP, RMOL, and RGF, respectively. The four occlusal modes had smaller effects on strain distribution in the cortical bone, cancellous bone, and miniscrews. Occlusal mode strongly influenced von Mises strain on the canine PDLs when orthodontic force was applied. When an FE model is used to analyze the biomechanical behavior of orthodontic treatments, the effect of muscle forces caused by occlusion must be considered.

Closure of large alveolar defect by maxillary alveolar distraction using a vector-controlled distractor appliance in cleft patients: A pilot study

ObjectiveTo assess the treatment outcome of custom made maxillary transport distractor appliance for closure of large alveolar clefts. MethodA pilot study was conducted on 12 large alveolar cleft defects present in 11 non-syndromic cleft lip and palate patients (1 bilateral and 10 unilateral) in the age group of 16–25 years. All the subjects underwent pre-surgical orthodontics followed by alveolar distraction using custom-made distractor appliance. Study models, lateral cephalogram, panoramic radiograph and cone beam computed tomograms were obtained pre-surgically (T0) and after distractor removal (T1). The reduction in the width and volume of the alveolar cleft defect and change in the mesiodistal axial inclination of the teeth in transport segment following distraction were recorded. P value ​< ​0.05 was considered statistically significant. ResultsSignificant reduction in cleft width (9.18 ​mm), volume (89.82 ​mm3) and the change in the mesiodistal axial inclination of the teeth in the transport segment (3.05°) (P ​< ​0.05) were observed. SNA (1.75°), ANB (1.58°), maxillary length (1.58 ​mm), upper incisor inclination (3°) and distal movement of anchorage teeth (0.95 ​mm) also showed significant change (P ​< ​0.05). ConclusionThe custom-made tooth borne distraction appliance successfully closed the large alveolar cleft defect with minimal or no inadvertent effects on the oral tissues.

Effects of different aligner materials and attachments on orthodontic behavior

Background/purposeThe orthodontic aligner becomes popular worldwide in orthodontic therapy as an esthetic alternative to fixed labial braces. This study evaluated orthodontic tooth movement behavior using different aligner materials and attachment shapes for the movement of a single tooth. Materials and methodsFirst bicuspid extracted resin typodont models were printed with a 3D printer. Three type of attachments, an ellipsoid shape (thick and thin) and a bar, were designed to fit the canine crown surface. Three types of aligner materials, Polyethylene Terephthalate enhanced with glycol (BIOSTAR) Polyethylene Terephthalate (BenQ), and Thermoplastic polyurethanes (TPU) were used to fabricate different aligners. The typodonts with aligners were sunk in a water bath to simulate canine distal movement in vivo. The canine crown, root movement, and long axis angle changes in each step were calculated and recorded. The data were analysed using a oneway ANOVA statistical method. ResultsComparing the three aligners, the changes the long axis of the canine showed that the BENQ group had a smaller change in the long axis angle. The BENQ group canine involved bodily movement, but the canine movement of the BIOSTAR and TPU group involved tipping. Comparing the three attachments, the bar type attachment had more canine crown tipping in the BIOSTAR and TPU groups. The thick and thin ellipsoid-shaped attachments showed no statistical differences in tooth movement. ConclusionAttachment shape or size had little influence on the bodily movement of the tooth. A high modulus material may thus be suitable for clinical applications.

Three-dimensional cone-beam computed tomography comparison of shorty and standard Class II Carriere Motion appliance.

To compare treatment effects of the standard and shorty Class II Carriere Motion appliances (CMAs) on adolescent patients. Fifty adolescents with Class II malocclusion formed group 1, who were treated with shorty CMA (n = 25, 12.66 ± 1.05 years), and age- and sex-matched group 2, who were treated with standard CMA (n = 25, 12.73 ± 1.07 years). Treatment effects were analyzed by tracing with Invivo software to compare pretreatment (T1) cone-beam computed tomography (CBCT) images with post-CMA (T2) CBCT images. A total of 23 measurements were compared within and between groups. In groups 1 and 2, maxillary first molars showed significant distal movement from T1 to T2 (1.83 ± 2.11 mm and 2.14 ± 1.34 mm, respectively), with distal tipping and rotation in group 1 (6.52° ± 3.99° and 3.15° ± 7.52°, respectively) but only distal tipping (7.03° ± 3.45°) in group 2. Similarly, in both groups, the maxillary first premolars experienced significant distal movement with distal tipping but no significant rotation. In group 1, maxillary canines did not undergo significant distal movement. In both groups 1 and 2, mandibular first molars experienced significant mesial movement (1.85 ± 1.88 mm and 2.44 ± 2.02 mm, respectively). Group 1 showed statistically significantly less reduction in overjet and less canine distal movement with less distal tipping than group 2 (α < .05). The shorty CMA achieved Class II correction similarly to the standard CMA, with less change in overjet and distal tipping movement of the maxillary canines.

Keys to Class II correction: A comparison of 2 extraction protocols

The purpose of this study was to evaluate the effects of 2 extraction patterns on incisor and molar movements in patients with growing Class II Division1. The sample included 54 patients 10-17years of age treated by 2 private practice orthodontists using Tweed directional force mechanics, 4 premolar extractions, J-hook headgears, and Class II elastics or Saif springs. The sample was divided on the basis of having maxillary and mandibular first premolars (4/4) or maxillary first and mandibular second premolars (4/5) extracted. Each group included 27 patients. Treatment lasted 2.8±0.60years and 2.6±0.54years for the 4/4 and 4/5 groups, respectively. Pretreatment (T1) and posttreatment lateral cephalograms and dental casts were evaluated. Cranial base, mandibular, and maxillary superimpositions were performed to quantify tooth movements and displacements. There were no statistically significant T1 between-group differences in crowding or in the SNA, SNB, ANB, and MPA angles. Analyses of covariance, controlling for statistically significant (P<0.05) differences in T1 mandibular incisor position, showed that mandibular first premolars extractions produced greater (1.6mm) mandibular incisor retraction than second premolar extractions. The mandibular first molars were protracted significantly more (0.7mm) after the second premolar than the first premolar extractions. Within-group changes of the MPA, between-group differences in the changes in MPA, and the amount of vertical eruption of the maxillary and mandibular molars were not significantly different between the 2 extraction patterns. Extraction of mandibular second premolars enhances Class II molar correction, with greater mesial first molar movement and less distal incisor movement. Neither extraction pattern has an effect on the MPA or the vertical dimension (ie, there was no "wedge effect").

En-masse intrusion and retraction with preadjusted edgewise appliance using two different sites of mini-implant placement

This article compares the treatment outcome between two patients when en-masse intrusion and retraction of the maxillary anterior teeth were performed with mini-implants placed at different sites. Both the patients had a skeletal Class II malocclusion with Angle's Class I molar relation, Class I canine relation, proclination of upper and lower anterior teeth. In the first case, intrusion and retraction was done with conventional friction mechanics for space closure and an intrusive force from a mini-implant placed in the midline. In the second case, intrusion and retraction were done with the application of force from the anterior attachments to mini-implants placed between the second premolars and first permanent molar bilaterally. There was intrusion of the maxillary anterior teeth with both mechanics. However, the evaluation of treatment outcome at the end of space closure showed mesial movement of the maxillary first permanent molar in the first case. In the second case, distal movement and intrusion of the maxillary first permanent molar and decrease in the lower anterior facial height was noted. The mechanics in the first case can be applied for intrusion and retraction of maxillary anterior teeth when anchorage requirement is not critical. The mechanics described in the second case can be used for intrusion and retraction of maxillary anterior teeth in cases with a very high anchorage need and will be beneficial in patients with vertical growth pattern.

Space management with gerber space regainer

Mesial migration of primary 2nd molar and 1st permanent molar occurs due to early exfoliation of primary first molar. Early exfoliation of deciduous teeth may lead to destruction in the integrity of normal occlusion. Early orthodontic procedures are often used to facilitate favorable developmental modifications in the developing occlusion. There are different space regaining methods described in literature. This case report presents a space regaining accomplished with distal movement of tooth by Gerber Space Regainer.

EXTERNAL FOCUS OF ATTENTION AFFECTS SHOT ACCURACY IN ELITE ARCHERS

The intention of this study was to find out if external focus of attention, steering the archers’ focus on distal movement effects, will provide better shooting accuracy expressed as higher number of 10 points and higher overall result. The subject sample was consisted of 10 elite male archers, with average age 25.8 years. The sample of variables was derived from observed characteristics of entities in different shooting conditions. A measure of arrow distance from the center of the target face was used in order to estimate shooting precision. The testing consisted of three different shooting conditions: C1- free focus of attention, C2 – internal focus of attention and C3 – external focus of attention. The analysis showed that the highest results were obtained in condition of externally oriented focus of attention (C3), and the lowest results in condition of internally oriented focus of attention (C2). Friedman’s ANOVA did not show statistical differences between the conditions, but they were found between C2 and C3 in afterwards administered Wilcoxon’s test (p=0.047).

Simultaneous distal movement of the maxillary first and second premolars can be achieved by distal movement of the maxillary first molar using a headgear

ABSTRACT Purpose: The purpose of this study was to investigate the precise effects of a headgear (HG) on the maxillary first premolar (U4), maxillary second premolar (U5), and maxillary first molar (U6). Materials and methods: The participants were divided into two groups: HG group and control group. The HG group consisted of 25 patients who were treated with an HG and maxillary lateral expansion. The control group consisted of 21 patients who received maxillary lateral expansion treatment. Movements of U4, U5, and U6 were measured using cone-beam computed tomography (CBCT). The mesiodistal positions of U4, U5, and U6 were assessed based on the vertical reference plane (VRP) defined by the landmarks of the maxilla. Results: Distal movement of U4, U5, and U6 was observed in the HG group, while mesial movement of U4, U5, and U6 was observed in the control group. Moreover, the positions of U4 and U5 were more distal than that of U6 in the HG group, while the positions of U4 and U5 were less mesial than that of U6 in the control group. The amount of distal movement of U4 and U5 was strongly correlated with that of U6 in the HG group. Conclusions: Simultaneous distal movement of U4 and U5 can be achieved with U6 distal movement using an HG in the early mixed dentition period. Moreover, the amount of distal movement of U4 and U5 was larger than that of U6. Hence, early orthodontic treatment using HG appears to be effective for correcting Class II malocclusion.

The effectiveness of traditional corticotomy vs flapless corticotomy in miniscrew-supported en-masse retraction of maxillary anterior teeth in patients with Class II Division 1 malocclusion: A single-centered, randomized controlled clinical trial

This single-centered, parallel-groups trial aimed to evaluate the efficacy of traditional corticotomy vs flapless corticotomy in accelerating en-masse retraction. In addition, to assess the skeletal, dental, and soft-tissue variables, as well as the external apical root resorption (EARR) of the maxillary anterior teeth. Forty patients with Class II Division 1 malocclusion aged>18years at the beginning of treatment, requiring maxillary first premolar extractions, were randomly distributed into 2 groups (n=20 each): 1 group was treated using traditional corticotomy, and the other group was treated with flapless corticotomy in en-masse retraction with anchorage based on miniscrews placed between maxillary second premolars and first molars bilaterally. Randomization was implemented with a computer-generated list of random numbers; allocation was concealed in sequentially numbered, opaque, sealed envelopes. The study was single-blinded (outcomes' assessor). The primary outcome was the en-masse retraction duration. Secondary outcomes were the skeletal, dental, and soft-tissue changes on lateral cephalometric and the EARR of maxillary anterior teeth on digital panoramic radiographs. The en-masse retraction duration in the flapless corticotomy group was longer than the traditional corticotomy group. The average retraction duration was 4.04±1.10months for the flapless corticotomy group and 3.75±2.14months for the traditional corticotomy group, with no significant difference between the 2 groups (95% confidence interval [CI], -0.81 to 1.39; P=0.59). No significant differences were observed between the 2 groups regarding changes in several lateral cephalometric variables (eg, SNA angle [95% CI, -2.55° to 1.66°; P=0.67], SN-U1angle [95% CI, -1.70° to 1.32°; P=0.80], and UL-E [95% CI: -1.33 to 1.00mm; P=0.78]) or in the amount of EARR in the maxillary anterior teeth (P=0.31). The proportion of the observed EARR ranged from 1% to 6% of root length in both corticotomy groups. No serious harms were observed in both groups. No significant differences between the flapless and traditional corticotomies were found in terms of the skeletal, dental, and soft-tissue variables as well as in the amount of EARR. Corticotomy-assisted en-masse retraction led to improvements in skeletal structures and facial profile and resulted in sufficient retraction of maxillary anterior teeth, slight distal movement of maxillary first molars, and an intrusion movement for both anterior and posterior teeth. Both corticotomy techniques did not cause significant EARR. ClinicalTrials.gov (Identifier: NCT03279042). The protocol was not published before the trial commencement.

Development, structure, and protein composition of reptilian claws and hypotheses of their evolution.

Here, we review the development, morphology, genes, and proteins of claws in reptiles. Claws likely form owing to the inductive influence of phalangeal mesenchyme on the apical epidermis of developing digits, resulting in hyperproliferation and intense protein synthesis in the dorsal epidermis, which forms the unguis. The tip of claws results from prevalent cell proliferation and distal movement along most of the ungueal epidermis in comparison to the ventral surface forming the subunguis. Asymmetrical growth between the unguis and subunguis forces beta-cells from the unguis to rotate into the apical part of the subunguis, sharpening the claw tip. Further sharpening occurs by scratching and mechanical wearing. Ungueal keratinocytes elongate, form an intricate perimeter and cementing junctions, and remain united impeding desquamation. In contrast, thin keratinocytes in the subunguis form a smooth perimeter, accumulate less corneous beta proteins (CBPs) and cysteine-poor intermediate filament (IF)-keratins, and desquamate. In addition to prevalent glycine-cysteine-tyrosine rich CBPs, special cysteine-rich IF-keratins are also synthesized in the claw, generating numerous SS bonds that harden the thick and compact corneous material. Desquamation and mechanical wear at the tip ensure that the unguis curvature remains approximately stable over time. Reptilian claws are likely very ancient in evolution, although the unguis differentiated like the outer scale surface of scales, while the subunguis might have derived from the inner scale surface. The few hair-like IF-keratins synthesized in reptilian claws indicate that ancestors of sauropsids and mammals shared cysteine-rich IF-keratins. However, the number of these keratins remained low in reptiles, while new types of CBPs function to strengthen claws.

Maxillary dento-skeletal outcomes after orthopedic forward (class III) and backward (class II) traction in growing subjects.

This retrospective study investigated the treatment effects produced by two orthopedic appliances, an extraoral orthopedic traction on Stephenson plate (SP) in skeletal Class II malocclusion and Delaire Facial Mask (FM) in skeletal Class III malocclusion. FM Group comprised 25 patients (13 males; 12 females, mean age 9.3 years, CS 1-2) undergoing Delaire Facial Mask therapy (mean treatment duration 1.5 years ± 1.2, 700-800 gr per side). SP Group comprised 24 patients (9 males; 15 females, mean age 10.5 years ± 1.9, CS 1-3) treated with extraoral orthopedic traction on Stephenson plate (mean treatment duration 1.6 years ± 0.8, 700-900 gr per side). For all subjects lateral cephalograms before (T0) and after (T1) therapy were obtained and traced. Descriptive statistics, t-test and Shapiro-Wilks test were calculated for each variable. A mesial movement of the maxillary bone of 2.4 mm in the FM group and a distal movement in the PS group (0.4 mm) was found. SNA° was reduced 1.4° after SP and increased 0.7° after FM. The overjet decreased by 4 mm after SP, while it grew after FM by 2.4 mm, as well as molars relationships (4.5 vs. 0.8 mm). Facemask induced greater skeletal movements than extraoral traction on Stephenson plate. PS produced a limited downward movement of the whole maxilla together with notable incisors and molars back corrections. Based on our results, it could be speculated that orthopedic mesial traction of maxillary bone may result easier than the distal movement.

Double vs single primary tooth extraction in interceptive treatment of palatally displaced canines.

To compare the impact of primary canine and primary first molar extractions with extractions of only the primary canine regarding correction of palatally displaced canines (PDCs). Thirty-two children aged 9.5-13.5 years with 48 PDCs were randomly allocated to either the double-extraction group (DEG) or single-extraction group (SEG). Clinical and radiographic examinations were performed at baseline and at 6-month intervals until the canine emerged or orthodontic treatment was started. Outcome measures were: emergence of maxillary canine (yes/no), emergence of maxillary canine into a favorable position (yes/no), and maxillary canine positional change (angulation and sector). Factors influencing PDC emergence were analyzed using logistic regression. In the DEG, 64% (16/25) of canines emerged into the oral cavity vs 78% (18/23) in the SEG (P = .283). Favorable PDC position at trial end was seen in 64% (16/25) of the DEG vs 57% (13/23) of the SEG (P = .600). Significant distal movement of PDCs was recorded in the DEG and SEG, though no significant difference was observed between groups. Significant predictors of canine emergence were initial canine angulation (Angle A) (P = .008) and space conditions at T0 (P = .030). Double or single primary tooth extraction procedures are equivalent in supporting PDC eruption into the oral cavity and into a favorable position in the dental arch. Initial canine angulation and space assessments may be used as predictors of successful PDC eruption.

Distalization of the entire maxillary arch with mini-implants in the posterior palatal alveolus- A case report

A 22 year old male patient reported to the hospital with a chief complaint of forwardly placed teeth. On examination patient had Angle’s Class I malocclusion and proclination of the anterior teeth. There were signs of frictional keratosis on the buccal mucosa. Treatment plan was to extract the third molars alone and distalize the entire maxillary arch with palatal mini-implants. 0.022 MBT brackets were bonded on the buccal aspect. 0.019” x 0.025” stainless steel wire was placed sequentially. Mini-implants were placed on the posterior alveolus on the palatal surface of maxilla. Retractive force was applied from an attachment bonded on the palatal aspect of the maxillary canine. Patient was reviewed periodically. Comparison of pre-treatment and posttreatment results revealed that the entire maxillary arch intruded and translated distally with a counterclockwise rotation of the mandible with reduction in LAFH. There was a mild reduction in inter-canine with marginal expansion in the premolar and molar region. An improvement in facial profile was noted with no sign of root resorption. Thus, the posterior alveolus may be considered as a new and appropriate site for placement of mini-implant to bring about distal movement of the entire maxillary dentition.KeywordsOrthodontic anchorage procedures; Bone screw; Palate.

Polymer-Based Endografts Have Improved Rates of Proximal Aortic Neck Dilatation and Migration

Proximal aortic neck dilatation (PND) affects a considerable proportion of patients undergoing endovascular aneurysm repair (EVAR) and is associated with increased rates of type I endoleak, migration and reinterventions. Although there are numerous studies investigating PND following the placement of endografts that use self-expanding stents, there are no such reports for patients treated with endografts that use polymer-filled sealing rings. The purpose of this study is to examine PND and graft migration after EVAR with the Ovation stent graft. The study included patients who underwent EVAR as part of the prospective international multicenter Ovation stent graft trial. A clinical events committee adjudicated adverse events through 1 year, an independent imaging core laboratory analyzed imaging through 5 years, and a data safety and monitoring board provided study oversight. Neck diameter was measured at the level of the lowest renal artery. PND was defined as neck enlargement of ≥ 3 mm. Graft migration was defined as distal movement >10 mm or movement of ≤10 mm when resulting in secondary intervention. A total of 238 patients received this device during the study period. Patients were predominantly male (81%), elderly with a mean age of 73 ± 8 years. Median follow-up was 58 months (interquartile range, 36-60). Almost one-half the patients (110 patients, 46%) had a challenging anatomy defined as outside the instructions for use with other stent grafts, 41 patients (17.2%) had a proximal neck length <10 mm and 93 (39%) had a minimum access vessel diameter <6 mm. The technical success rate was 100%. The 1-, 3- and 5-year overall survival rates were 96.6%, 86.2% and 75%, respectively. The immediate postoperative proximal neck diameter ranged from 15.5 to 31.4mm with a mean of 22 ± 3 mm. During follow-up, four patients (1.7%) developed PND. Freedom from PND estimates at 1, 3 and 5 years were 99%, 97.9% and 97.9%, respectively (Figure). None of the patients developed significant endograft migration. The use of the Ovation stent graft was associated with excellent Results with very low rates of PND despite challenging neck anatomy in 39% of patients. No graft migration was observed. The design of this endograft may explain its superiority to self-expanding stents in preventing neck dilatation and migration. This is important, as we continue to see significant late failures of EVAR due to proximal neck degeneration.

Avitograptus species (Graptolithina) from the Hirnantian (uppermost Ordovician) Anji Biota of South China and the evolution of Akidograptus and Parakidograptus

AbstractThe latest Ordovician to earliest Silurian graptolite Avitograptus avitus is important in the biostratigraphy of the Ordovician–Silurian boundary interval. Two additional species of Avitograptus are described from the sponge-dominated Anji Biota of the Upper Ordovician Wenchang Formation (Metabolograptus persculptus Biozone) of Zhejiang Province, South China. One species, Avitograptus akidomorphus new species, is new; the other, Avitograptus acanthocystus new combination, which was previously placed in Climacograptus, is herein assigned to Avitograptus. The former species may represent the ancestral akidograptid because it is identical in thecal form to Akidograptus, but differs in the development of the proximal end. The evolutionary changes from Avitograptus avitus to Akidograptus and Parakidograptus involved distal movement of the origins of th11 and th12, thecal elongation, and greater outward inclination of the thecal walls.UUID: http://zoobank.org/81c433a0-9069-48d2-ae72-1267400cbf77.

The Class II Carriere Motion appliance.

To determine three-dimensional treatment changes produced by the Class II Carriere Motion appliance (CMA) in Class II adolescent patients with Class I and Class II skeletal relationships. The sample included 59 adolescents (16 boys and 43 girls) with unilateral or bilateral Class II molar and bilateral Class II canine relationship. They were divided into group 1 with skeletal Class I (N = 27; ANB 2.90° ± 1.40°; 13.30 ± 1.53 years) and group 2 with skeletal Class II (N = 32; ANB 6.06° ± 1.64°; 13.26 ± 1.76 years). Cone beam computed tomography images were traced with Invivo software pretreatment (T1) and post-CMA usage (T2). The treatment changes in 36 measurements were calculated in each group, and the changes in 16 measurements were compared between them. In group 1 and 2, maxillary first molars underwent significant distal movement (1.92 mm ± 0.80 mm and 1.67 mm ± 1.56 mm, respectively) with distal tipping and rotation, maxillary canines underwent significant distal movement (2.34 mm ± 1.07 mm and 2.24 mm ± 1.91 mm, respectively) with distal tipping and rotation, and mandibular molars underwent significant mesial movement (-1.37 mm ± 1.23 mm and -2.51 mm ± 1.51 mm, respectively) with mesial tipping. Between the groups, there were significant differences in mandibular molar mesial movement and the U1-SN changes (P < .05). The CMA corrected Class II malocclusion through distal tipping and rotational movement of maxillary canines and molars and corrected mesial tipping of mandibular molars. Significantly more mandibular molar mesial movement and maxillary incisor flaring were observed in patients with skeletal Class II.

Does corticotomy accelerate canine retraction with adequate anchorage control? A split mouth randomized controlled trial

ABSTRACT Purpose: To assess the effects of corticotomy on the distal movement of canine and to assess the amount of molar anchor loss. Materials and Methods: 14 patients were selected for this prospective, split-mouth, randomized controlled trial. After bilateral maxillary first premolar extractions, corticotomy was done distal to canine on one side and 150 g of force was applied. The rate of canine and molar movement, tipping and rotation were evaluated for control and experimental side. The movement of canine and anchor loss was assessed at an interval of 3 weeks, using study models, till single canine retraction was complete. Subjective assessment of the post-surgical pain, swelling, discomfort and an overall patient perception of the surgical procedure was assessed at two time points. Results: There was a significant increase in the rate of canine movement on the experiment side at T1 and T2 (p ≤ 0.01). Anchor loss was found to be present on both the sides but the difference was not statistically significant (p > 0.05). The mesiodistal tipping of canine was found to be greater on the control side than the experiment side whereas there was no statistically significant difference in the mesiodistal tipping of the molar on either side (p > 0.05). The experiment group showed a greater rotation of canine than the control (p ≤ 0.05), however, the rotation of molar was statistically insignificant. Conclusion: Corticotomy-assisted canine retraction causes a significant increase in the rate of canine retraction for the initial 2 months of the post-corticotomy period.

Maxillary molar distalization in treatment of angle class II malocclusion growing patients: Uncontrolled clinical trial

This study was conducted to evaluate the clinical effectiveness treatment effects of a simple buccal technique for maxillary molar distalization using direct buccal skeletal anchorage. After sample size calculation, fourteen female patients with bilateral Class II molar relationship (age 11-14 years) were selected from the clinic of the Department of Orthodontics, Faculty of Dentistry, Mansoura University, Egypt. After the application of the eligibility criteria, only eleven patients remained to final evaluation. The criteria included: erupted second maxillary molars, mild to moderate maxillary crowding not exceeding 6mm with/without increased overjet and non-extraction treatment in the lower arch. After alignment and levelling, a miniscrew (1. 8mm diameter - 0. 8mm long) was placed buccally between the maxillary second premolar and the first molar in each side. The maxillary molar distalization was done using 250 grams of force produced from NiTi closed coil spring stretched to a buccal miniscrew. Records including cephalometric x-rays and study casts were taken for all patients before and after molar distalization. Statistical evaluation was performed for the data obtained from analysis of cephalometric tracing and cast photocopies. The maxillary first molars were distalized with a rate of 0. 89±0. 30mm (95% CI 0.76-1.02) (P<0.001) and distalization amount of 4.09±0. 92mm (CI 3.68-4.50) (P<0.001). They were distally tipped by 2.48°±6. 16 (CI -0.26-5.21) (P=0.073) and rotated distopalatally by 11.89°±5.86 with negligible change in their vertical position about 0.11±0.63mm (CI -0.40-0.17) (P=0.411). There was no anchorage loss evident by the distal movement of all the maxillary teeth (P<0.001). Overjet significantly reduced by 0. 86±0. 50 (CI 0.52-1.20) (P=0.004). Maxillary molar distalization using a closed coil and buccal miniscrew is an effective and non-compliance dependent technique in a relatively short time.