scholarly journals Optimizing Anterior En Masse Retraction with Miniscrew Anchorage

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Pavankumar Janardan Vibhute
Keyword(s):  
Side Effects ◽  
Skeletal Anchorage ◽  
Risk Of Infection ◽  
Force Vector ◽  
Posterior Teeth ◽  
Attached Gingiva ◽  
Anchorage Loss ◽  
Sliding Mechanics ◽  
Retraction Force ◽  
En Masse Retraction

In severely protrusive patients, skeletal anchorage from miniscrew is often used to avoid anchorage loss with preferred miniscrew location near centre of resistance (Cres) of posterior teeth. Biomechanical requirement for directing retraction force towards Cres of posterior teeth demands the insertion of miniscrew in loose mucosa, where risk of infection and failure increases. In addition, undesirable biomechanical side effects on anterior and posterior segments may be possible in all three planes, when continuous arch sliding mechanics are installed with miniscrew anchorage. This paper describes technique of molar-stabilizing power arm (MSPA) for simultaneous intrusion and retraction of anteriors with miniscrew placement at attached gingiva between 1st molar and 2nd premolar. Advantages of this technique include (i) the need of miniscrews placement in loose mucosa apically near the Cres of the posterior teeth is eliminated, (ii) the risk of infection and miniscrew failure is lowered since the miniscrew is placed in attached gingiva rather than the loose mucosa, and (iii) by adjusting vertical length or replacing MSPA, alteration of the retraction force vector is possible in all three planes; thus, need of removal and repositioning of the miniscrew (e.g., in correction of occlusal cant) can be eliminated.

scholarly journals Dual-section versus conventional archwire for en-masse retraction of anterior teeth with direct skeletal anchorage: a finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Hamanaka ◽  
Daniele Cantarella ◽  
Luca Lombardo ◽  
Lorena Karanxha ◽  
Massimo Del Fabbro ◽  
...  
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Occlusal Plane ◽  
Skeletal Anchorage ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Posterior Portion ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction

Abstract Background The aim of this study is to compare the biomechanical effects of the conventional 0.019 × 0.025-in stainless steel archwire with the dual-section archwire when en-masse retraction is performed with sliding mechanics and skeletal anchorage. Methods Models of maxillary dentition equipped with the 0.019 × 0.025-in archwire and the dual-section archwire, whose anterior portion is 0.021 × 0.025-in and posterior portion is 0.018 × 0.025-in were constructed. Then, long-term tooth movement during en-masse retraction was simulated using the finite element method. Power arms of 8, 10, 12 and 14 mm length were employed to control anterior torque, and retraction forces of 2 N were applied with a direct skeletal anchorage. Results For achieving bodily movement of the incisors, power arms longer than 14 mm were required for the 0.019 × 0.025-in archwire, while between 8 and 10 mm for the dual-section archwire. The longer the power arms, the greater the counter-clockwise rotation of the occlusal plane was produced. Frictional resistance generated between the archwire and brackets and tubes on the posterior teeth was smaller than 5% of the retraction force of 2 N. Conclusions The use of dual-section archwire might bring some biomechanical advantages as it allows to apply retraction force at a considerable lower height, and with a reduced occlusal plane rotation, compared to the conventional archwire. Clinical studies are needed to confirm the present results.

scholarly journals Initial forces experienced by the anterior and posterior teeth during dental-anchored or skeletal-anchored en masse retraction in vitro

2016 ◽  
Vol 87 (4) ◽  
pp. 549-555 ◽  
Author(s):  
David Lee ◽  
Giseon Heo ◽  
Tarek El-Bialy ◽  
Jason P. Carey ◽  
Paul W. Major ◽  
...  
Keyword(s):  
Anterior Segment ◽  
Nickel Titanium ◽  
Skeletal Anchorage ◽  
Posterior Teeth ◽  
Treatment Groups ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction ◽  
Maxillary Arch

ABSTRACT Objective: To investigate initial forces acting on teeth around the arch during en masse retraction using an in vitro Orthodontic SIMulator (OSIM). Materials and Methods: The OSIM was used to represent the full maxillary arch in a case wherein both first premolars had been extracted. Dental and skeletal anchorage to a posted archwire and skeletal anchorage to a 10-mm power arm were all simulated. A 0.019 × 0.025-inch stainless steel archwire was used in all cases, and 15-mm light nickel-titanium springs were activated to approximately 150 g on both sides of the arch. A sample size of n = 40 springs were tested for each of the three groups. Multivariate analysis of variance (α = 0.05) was used to determine differences between treatment groups. Results: In the anterior segment, it was found that skeletal anchorage with power arms generated the largest retraction force (P < .001). The largest vertical forces on the unit were generated using skeletal anchorage, followed by skeletal anchorage with power arms, and finally dental anchorage. Power arms were found to generate larger intrusive forces on the lateral incisors and extrusive forces on the canines than on other groups. For the posterior anchorage unit, dental anchorage generated the largest protraction and palatal forces. Negligible forces were measured for both skeletal anchorage groups. Vertical forces on the posterior unit were minimal in all cases (<0.1 N). Conclusions: All retraction methods produced sufficient forces to retract the anterior teeth during en masse retraction. Skeletal anchorage reduced forces on the posterior teeth but introduced greater vertical forces on the anterior teeth.

scholarly journals En Masse Retraction and Two-Step Retraction of Maxillary Anterior Teeth in Adult Class I Women

2007 ◽  
Vol 77 (6) ◽  
pp. 973-978 ◽  
Author(s):  
Wook Heo ◽  
Dong-Seok Nahm ◽  
Seung-Hak Baek
Keyword(s):  
Class I ◽  
Female Adult ◽  
Posterior Teeth ◽  
Anterior Teeth ◽  
Lateral Cephalograms ◽  
Group 2 ◽  
Anchorage Loss ◽  
Root Apices ◽  
En Masse Retraction ◽  
Group 1

Abstract Objective: To compare the amount of anchorage loss of the maxillary posterior teeth and amount of retraction of the maxillary anterior teeth between en masse retraction and two-step retraction of the anterior teeth. Materials and Methods: The sample consisted of 30 female adult patients with Class I malocclusion and lip protrusion who needed maximum posterior anchorage. The sample was subdivided into group 1 (n = 15, mean age = 21.4 years, en masse retraction) and group 2 (n = 15, mean age = 24.6 years, two-step retraction). Lateral cephalograms were taken before (T1) and after treatment (T2). Nine skeletal and 10 anchorage variables were measured, and independent t-test was used for statistical analysis. Results: Although the amount of horizontal retraction of the maxillary anterior teeth was not different between the two groups, there was mild labial movement of the root apices of the upper incisors in group 2 at T2. There were no significant differences in the degree of anchorage loss of the maxillary posterior teeth between the two groups. Bodily and mesial movements of the upper molars occurred in both groups. Approximately 4 mm of the retraction of the upper incisal edges resulted from 1 mm of anchorage loss in the upper molars in both groups. Conclusion: No significant differences existed in the degree of anchorage loss of the upper posterior teeth and the amount of retraction of the upper anterior teeth associated with en masse retraction and two-step retraction of the anterior teeth.

scholarly journals Efficiency of the skeletonized Pendulum K appliance for non-compliance maxillary molar distalization

2021 ◽  
Author(s):  
Gero Stefan Michael Kinzinger ◽  
Jan Hourfar ◽  
Jörg Alexander Lisson
Keyword(s):  
Side Effects ◽  
Lower Percentage ◽  
Molar Distalization ◽  
Maxillary Molars ◽  
Maxillary Molar ◽  
Force Moment ◽  
Maxillary Premolars ◽  
Anchorage Loss ◽  
Upper Molar

Abstract Purpose Conventional anchorage with exclusively intraorally anchored appliances for non-compliance molar distalization combines a palatal acrylic button with periodontal anchorage. This type of anchorage is critically discussed because of the temporary hygienic impairment of the palate and the uncertain anchoring quality of the button. A purely dentally/periodontally anchored Pendulum K appliance was developed, which is exclusively anchored via four occlusal rests. The aims of this pilot study were to examine the suitability of the skeletonized Pendulum K for distalization of maxillary molars, and to investigate the quality of this alternative anchoring modality. Patients and methods In all, 10 patients received skeletonized Pendulum K appliances attached to all maxillary premolars for bilateral molar distalization. Supporting anchorage through an acrylic button adjacent to the anterior palate was not used. The pendulum springs were initially activated on both sides with a distalization force of 220 cN each and provided with uprighting and toe-in bends. The specific force/moment system was regularly reactivated intraorally by adjustment of the distal screw. Results The study demonstrates the suitability of the skeletonized Pendulum K appliance for the distalization of maxillary molars (3.28 ± 0.73 mm). Side effects on the molars were slight distal tipping (3.50 ± 2.51°/PP, 3.00 ± 1.41°/SN) and mesial inward rotation (average 2.75 ± 7.50° and 4.50 ± 12.77°). Significant anchorage loss occurred in the form of mesialization of the incisors by 1.40 ± 0.82 mm and of the first premolars by 2.28 ± 0.85 mm. Conclusion The skeletonized Pendulum K appliance allows compliance-free upper molar distalization. Exclusively dental/periodontal anchorage resulted in a lower percentage of molar distalization compared to a conventional anchoring preparation of the Pendulum K with a palatal acrylic button. Anchorage loss had a comparatively stronger effect on the anchoring premolars but less on the incisors. Typical side effects on the molars such as distal tipping and mesial inward rotation were remarkably low.

scholarly journals Comparison of anterior retraction and anchorage control between en masse retraction and two-step retraction: A randomized prospective clinical trial

2018 ◽  
Vol 89 (2) ◽  
pp. 190-199 ◽  
Author(s):  
Patricia Pigato Schneider ◽  
Luiz Gonzaga Gandini Júnior ◽  
André da Costa Monini ◽  
Ary dos Santos Pinto ◽  
Ki Beom Kim
Keyword(s):  
Clinical Trial ◽  
Treatment Group ◽  
Secondary Outcome ◽  
Space Closure ◽  
The Difference ◽  
Maxilla And Mandible ◽  
Anchorage Loss ◽  
Bimaxillary Protrusion ◽  
Best Fit ◽  
En Masse Retraction

ABSTRACT Objectives: The purpose of this two-arm parallel trial was to compare en masse (ER) and two-step retraction (TSR) during space closure. Materials and Methods: Forty-eight adult patients with bimaxillary protrusion who were planned for treatment with extraction of four first premolars were enrolled. All patients were randomly allocated in a 1:1 ratio to either the ER (n = 24) group or the TSR (n = 24) group. The main outcome was the amount of posterior anchorage loss in the molars and the retraction of the incisors between ER and TSR; the difference in incisor and molar inclination was a secondary outcome. Lateral cephalometric radiographs and oblique cephalometric radiographs at 45° were taken before retraction (T1) and after space closure (T2). Cephalograms were digitized and superimposed on the anatomic best fit of the maxilla and mandible by one operator who was blinded to the treatment group. Results: Neither incisor nor molar crown movements showed any significant differences between the ER and TSR. There were no significant differences in the tipping of incisors and molars between the two groups. Conclusions: No significant differences existed in the amount of retraction of incisors and anchorage loss of molars between ER and TSR. Changes in incisor and molar tipping were similar, with the crowns showing more movement than the apex.

scholarly journals Three-dimensional analysis of the physiologic drift of adjacent teeth following maxillary first premolar extractions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fei Teng ◽  
Fei-Yu Du ◽  
Hui-Zhong Chen ◽  
Ruo-Ping Jiang ◽  
Tian-Min Xu
Keyword(s):  
Three Dimensional ◽  
Posterior Teeth ◽  
Fixed Appliance ◽  
Premolar Extraction ◽  
Negative Effect ◽  
Vertical Changes ◽  
Anchorage Loss ◽  
Drift Models ◽  
To Receive ◽  
Positive Effect

Abstract We assessed the three-dimensional (3D) pattern of the physiologic drift of the remaining adjacent teeth after premolar extraction due to orthodontic reasons and the associated factors. Data were collected from 45 patients aged 17.04 ± 5.14 years who were scheduled to receive a fixed appliance after maxillary premolar extraction. Seventy-five drift models were obtained and digitalized via 3D scanning. The average physiologic drift duration was 81.66 ± 70.03 days. Angular and linear changes in the first molars, second premolars, and canines were measured using the 3D method. All the examined teeth had tipped and moved towards the extraction space, leading to space decreases. Posterior teeth primarily exhibited significant mesial tipping and displacement, without rotation or vertical changes. All canine variables changed, including distal inward rotation and extrusion. The physiologic drift tended to slow over time. Age had a limited negative effect on the mesial drift of posterior teeth, whereas crowding had a limited positive effect on canine drift. Thus, the mesial drift of molars after premolar extraction may lead to molar anchorage loss, particularly among younger patients. The pattern of the physiologic drift of maxillary canines can help relieve crowding and facilitate labially ectopic canine alignment, whereas canine drift is accelerated by more severe crowding.

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