Maximum Anchorage Cases Research Articles

Cephalometric Evaluation of Changes in Tongue Position, Posture and Pharyngeal Airway Dimensions Following Treatment of Angle’s Class 1 Bimaxillary Proclination

Objectives:The aim of the study is to determine and correlate the effects of anterior teeth retraction on tongue position, posture and pharyngeal airway dimensions, in Angle’s Class 1 bimaxillary dentoalveolar proclination cases treated with all first premolar extraction. Materials and Methods:Pre and post treatment lateral cephalogram of fifteen Class I bimaxillary dentoalveolar proclination patients in the age group of 15-25years treated orthodontically as maximum anchorage cases with Preadjusted Edgewise Appliances (MBT prescription) and extraction of all first premolars were compared. Results:Tongue position analysis showed significant decrease in tg1: 2.2 +/- 1.52 mm (p = 0.001) and TGL: 4.2 +/- 3.877 mm (p = 0.001). Tongue posture analysis showed a significant decrease in Point 1: 1.48 +/- 1.92 mm (p=0.028), Point 2: 1.44 +/- 1.46 mm (p=0.008) and Point 5: 1.92 +/- 2.45 mm (p=0.026).Pharyngeal airway analysis showed significant increase in PNS-Ad1: 1.2 +/- 1.69 mm (p=0.016) while V-LPW: 2.0 +/- 3.047 mm (p=0.023) was decreased. No significant correlation was found between changes in total tongue length and velopharyngeal and glossopharyngeal airway. Conclusions:A significant reduction in the total tongue length particularly in the posterior region was observed after retraction. Also there was a reduction in the distance between root of the tongue and uvula, dorsum of the tongue and the roof of mouth in the posterior and anterior part of palate respectively. There was an increase in the lower nasopharyngeal airway and a decrease in the hypopharyngeal airway.

Comparison of the Efficiency and Treatment Outcome of Patients Treated with Corticotomy-Assisted En masse Orthodontic Retraction with the En masse Retraction without Corticotomy.

Background:Corticotomy in fixed orthodontic treatment gives a potential approach to reduce the treatment duration. Typically, this duration of rapid tooth movement lasts 4–6 months.Aim:The aim of this study was to compare the treatment outcome and effectiveness in en masse retraction with and without corticotomy.Materials and Methods:Thirty-two patients (male 16 and female 16) who opted to undergo surgery to reduce the orthodontic treatment time were chosen for the research, and the group consisted of 26 patients (male 13 and female 13) who did not opt for the corticotomy procedure were selected as the control. There was no blindness of the party distribution. It was focused on the patient's ability to opt for an additional minor surgical procedure that may affect orthodontic treatment length. The operation was conducted under local anesthesia (Lignox 2%). The same maxillofacial surgeon performed all the surgical operations.Results:The space present in the maxillary and mandibular arch at the time of retraction had no statistically significant difference in both the control and study groups (P > 0.05). In comparison, the mean amount of retraction space in the maxillary arch and maxillary arch was significant in the control and study groups at 1 month, 2 months, 3 months, and 4 months of the time interval.Conclusion:It can be concluded that corticotomy-assisted retraction significantly decreases the total length of orthodontic care. Effectively stationary anchorage segment was made, thereby removing the need for other anchorage boosters, instrumental in maximum anchorage cases using corticotomy technique.

A comparative study to evaluate the effectiveness of lateral cephalogram and study cast to measure anteroposterior anchorage loss with preadjusted edgewise appliance

Objective: Measurement of anchorage loss is an essential part of assessing the orthodontic treatment. It can be assessed on the lateral cephalogram or on study models. The purpose of the present study is to compare the mean horizontal molar movement or anchorage loss relative to the palatal rugae landmarks on study models with that of cephalometric superimpositions in maximum anchorage cases and to concur whether only one record (study casts or cephalogram) could suffice for the evaluation of the anchorage loss. Materials and Methods: A power analysis was performed to determine the sample size needed to detect a 1.0-mm difference in tooth movement with the effect size of 0.5 at a confidence level of 90%, to consider the dropouts thirty maximum anchorage patients requiring first premolar extraction as part of their treatment plan were selected by consecutive sampling. Mean horizontal movement of molars was calculated on lateral cephalogram and study cast records after alignment and leveling. Statistical Analysis: Paired t-test was performed to compare the mean values of anchorage loss measured on lateral cephalogram and study model. Results: The results showed that there was no statistically significant difference in measurement of anteroposterior anchorage loss with either lateral cephalogram or study cast (p – value 0.554). The mean horizontal molar movement measured on lateral cephalogram was 2.32 with SD of 1.77 and mean horizontal molar movement measured on study cast was 2.09 with SD of 1.22. Conclusion: The present study shows that the measurement of anchorage loss on study models is equally reliable as that on the lateral cephalogram. Thus, study models presents as an alternative to the measurement of anteroposterior anchorage loss. Keywords: Lateral cephalogram, study cast, Anchorage loss, Preadjusted edgewise.

Modified transpalatal auxiliary arch for enhanced anchorage and tooth movement

Intraoral appliances such as transpalatal arch and Nance appliance fail to resist forces that tend to loosen the anchorage. The infirmity arises due to the long-lever arm and the mesial force that is perpendicular to the long axis of the appliance. The butterfly arch is presented here as an intraoral appliance that withstands the mesially directed forces with a mechanism that puts strain on a stiff wire along its long axis. The unique shape of the butterfly arch is advantageous in maximum anchorage cases, cases in which arch width preservation is critical and cases with a vertical growth pattern. With the aid of the butterfly arch, clinical concerns such as patient cooperation, wearing extraoral appliances, complicated mechanics in extraction cases, and control of the arch length, arch width, and vertical dimension would be greatly diminished.

Assessment of minimum force required to initiate sliding of stainless steel wire in ceramic (monocrystalline and polycrystalline) and stainless steel preadjusted edgewise brackets using stainless steel and elastomeric ligation techniques – An in vitro study

Objectives: To compare the force required to initiate sliding of rectangular stainless steel wire in monocrystalline ceramic bracket v/s polycrystalline ceramic bracket v/s stainless steel bracket using stainless steel ligation technique and to compare the force required to initiate sliding of rectangular stainless steel wire in monocrystalline ceramic bracket v/s polycrystalline ceramic bracket v/s stainless steel bracket using elastomeric ligation technique. Methods: The archwire was pulled in a vertical direction by the testing machine, until the resistance was overcome and the archwire started to slide through the bracket. The force to overcome resistance and to initiate sliding of the archwire was measured. Results: In metal brackets, there is minimum resistance to sliding as compared to the two different ceramic brackets. Among the two ceramic brackets polycrystalline bracket offered more resistance to sliding then monocrystalline bracket. Although SS ligation offered less resistance to sliding then elastomeric ligation in all three bracket types, the difference between the two ligation systems is not statistically significant. Conclusions: In maximum anchorage cases metal bracket along with SS ligation should be used to reduce the frictional resistance, enabling the use of lighter forces and eventually conserving the anchorage.

Maxillary anterior en masse retraction using different antero-posterior position of mini screw: a 3D finite element study.

BackgroundNowadays, mini screws are used in orthodontic tooth movement to obtain maximum or absolute anchorage. They have gained popularity among orthodontists for en masse retraction of anterior teeth after first premolar extraction in maximum anchorage cases. The purpose of this study was to determine the type of anterior tooth movement during the time when force was applied from different mini screw placements to the anterior power arm with various heights.MethodsA finite element method was used for modeling maxillary teeth and bone structure. Brackets, wire, and hooks were also designed for modeling. Two appropriate positions for mini screw in the mesial and distal of the second premolar were designed as fixed nodes. Forces were applied from the mini screw to four different levels of anterior hook height: 0, 3, 6, and 9 mm. Initial tooth movement in eight different conditions was analyzed and calculated with ANSYS software.ResultsRotation of anterior dentition was decreased with a longer anterior power arm and the mesial placement of the mini screw. Bodily movements occurred with the 9-mm height of the power arm in both mini screw positions. Intrusion or extrusion of the anterior teeth segment depended on the level of the mini screw and the edge of the power arm on the Z axis.ConclusionsAccording to the findings of this study, the best control in the sagittal plane during anterior en masse retraction was achieved by mesial placement of the mini screw and the 9-mm height of the anterior power arm. Where control in the vertical plane was concerned, distal placement of the mini screw with the 6-mm power arm height had minimum adverse effect on anterior dentition.

Horizontal and vertical changes in anchor molars after extractions in bimaxillary protrusion cases

Objective To evaluate changes in the anchor molar position (horizontal, vertical) after retraction in bimaxillary protrusion maximum anchorage cases. Materials and Methods Thirty patients requiring maximum anchorage after extraction of the first premolars were selected for this study. The second molars were banded in both arches along with trans-palatal arch in the maxillary arch and lingual arch in the mandibular arch. En mass retraction was done using sliding mechanics. Horizontal and vertical positions of the anchor first molars were evaluated cephalometrically before and after orthodontic retraction. Results In the horizontal plane, maxillary first molars showed net mesial movement of 1.72 mm, and there was a statistical difference between the pre- and post-values (P < 0.001). The mandibular molars showed a net horizontal movement of 2.26 mm, and there was a statistically significant difference between the pre- and post-values (P < 0.001). In the vertical plane, there was vertical movement of the maxillary anchor molars by a net value of 0.95 mm which was statistically significant (P < 0.001). The mandibular anchor molars moved vertically by a net value of 0.45 mm. This difference was statistically not significant. Conclusion There was anchorage loss seen in both the planes (horizontal, vertical) of the maxillary anchor molars. In the mandibular anchor molars, there was anchorage loss seen only in the horizontal plane. No anchorage loss was seen in the vertical plane.

Mini-implants for the treatment of severe Class II division 1 malocclusion with anterior open bite and tongue thrusting habit

The case report describes the treatment of a male patient aged 16 years having anterior overjet of 8 mm, severe proclination of the upper anterior teeth and anterior open bite with severe tongue thrust habit. Two mini-implants were used in the upper arch only, for upper anterior en masse retraction following upper first bicuspid's extraction. A significant amount of dentoalveolar and soft tissue changes were accomplished with the utilization of mini-implants. Class II profile of the patient was eliminated along with the accomplishment of proper interdental relationship. Case was finished in Class II molar relationship with excellent stability of the same over a 2-year follow-up period. This case report demonstrates that the mini-implants can serve as an effortless, noncompliant method of reinforcing anchorage in maximum anchorage cases with tongue thrusting habit.

Efficacy of second molar to achieve anchorage control in maximum anchorage cases

Background: The aim of the study was to assess the efficacy of inclusion of second molar in treatment at the outset to reinforce anchorage. Methods: A comparative study comprising of 30 maximum anchorage cases to quantify anchorage loss in two situations was undertaken. Group I consisted of cases in which only first molars were banded and Group II consisted of cases where both first and second molars were banded. A total of seven landmarks were marked and six measurements were recorded on to the pre-treatment and post-treatment lateral cephalogram. Result: The difference in pre-treatment and post-treatment values of all the variables were statistically significant (p<0.05) except maxillary central incisor vertical movement (U1 VER), implying a significant post-treatment change. Thus in both the treatment approaches U6 and U1 showed a considerable amount of movement in horizontal and vertical direction and there was rotation which brought about change in angular values. Conclusion: The study has successfully quantified the anchorage loss and brought out the advantages of including second molar in treatment at the outset. Not only the anchorage loss is minimized but inclusion of second molar also helps to maximize incisor retraction and helps control angular movement of molar and incisor. Extra time required for second molar banding is well spent, as the benefits are overwhelming.

Effects of the zygoma anchorage system on canine retraction

The aim of this study was to compare the effects of the Gjessing (PG) retraction spring used with and without the zygoma anchorage system (ZAS) on canine retraction. Thirty patients, with an Angle Class I or Class II malocclusion, whose upper first premolars were scheduled for extraction, were divided into two equal groups. Group 1 comprised maximum anchorage cases (nine females and six males with a mean age of 16 years 8 months) in which the ZAS was used to improve posterior anchorage and the PG retraction springs for canine retraction. Moderate anchorage cases (10 females and 5 males with a mean age of 15 years 5 month) were included in group 2 and canine retraction was achieved using only PG retraction springs. Study models and lateral cephalometric radiographs obtained at the initial and final stages of canine retraction were used for comparison of the groups to determine the effects of zygoma anchorage on canine retraction. All measurements were evaluated statistically using a Student's t-test, 2 × 2 repeated measures analysis of variance, Bonferroni-adjusted t-test, and Mann-Whitney U and Wilcoxon tests according to the normality of the distribution of the variables. Mesial crown movement of the molars was 0.63 mm (P < 0.05) in group 1 and 1.50 mm (P < 0.001) in group 2. There was a statistically significant difference (P < 0.05) between the groups. No significant difference was observed between the groups for the rate of canine retraction or sagittal and vertical movement of the canines. The ZAS is a reliable and successful anchorage reinforcement method for canine retraction in extraction cases.

Anchorage loss--a multifactorial response.

Anchorage loss (AL) is a potential side effect of orthodontic mechanotherapy. In the present study, it is defined as the amount of mesial movement of the upper first permanent molar during premolar extraction space closure. In addition, AL is described as a multifactorial response in relation to the extraction site, appliance type, age, crowding, and overjet. For this study, 87 university clinic and private practice subjects, who were defined as maximum anchorage cases and had undergone bilateral maxillary premolar extractions, were divided into four groups according to extraction site (first vs second premolars), mechanics (lingual vs labial edgewise appliances), and age (adolescents vs adults). Overjet and crowding were examined from the overall sample. Data were collected from serial lateral cephalograms and dental casts. The results showed that as the severity of dental crowding increased, AL significantly decreased (r = -0.66, P = .001). Labial edgewise appliances demonstrated a significantly greater AL than did lingual edgewise appliances (1.15 +/- 2.06 mm, P < .05). A greater, though not statistically significant, AL was found in adults than in adolescents (0.73 +/- 1.43 mm). There was a slight nonsignificant increase in AL between maxillary second compared with first premolar extractions (0.51 +/- 1.33 mm). Overjet was weakly correlated to AL. These results suggest that AL is a multifactorial response and that the five examined factors can be divided into primary (crowding, mechanics) and secondary factors (age, extraction site, overjet), in declining order of importance.

“En Masse” retraction of maxillary anterior teeth with anterior headgear

In the treatment of the first premolar extraction cases with certain techniques, incisor retraction is realized after canine distalization. In maximum anchorage cases, retraction of anterior segments require more posterior anchorage. This treatment concept is still valid, however, the difficult anchorage control is considered a major drawback. The purpose of this study is to introduce our technique for the “en masse” retraction of maxillary anterior teeth after first premolar extraction and discuss its effects. The technique consists of the application of extraoral traction on canines, followed by banding of maxillary anterior teeth, to form them as a mass. Advantages of our mechanics are as follows: (1) Anterior headgear may have the advantage of retracting anterior teeth with minimum strain on posterior anchorage. (2) The adjustability of the outer bow in relation to the premaxilla's center of resistance, provides effective desired movements. (3) Intrusion and torque control are achieved in the course of anterior segment retraction. (Am J Orthod Dentofac Orthop 1997;112:473-9.)

Canine retraction with J hook headgear

Several methods have been described for accomplishing distal movement of canines without losing posterior anchorage. An accepted method in canine retraction is the use of headgear with J hooks. Since it incorporates extraoral anchorage, it is most effective in maximum-anchorage cases. It was the purpose of this study to analyze the distribution of force transmitted to the alveolus and surrounding structures by means of photoelastic visualization, utilizing J hook headgear for maxillary canine retraction. A three-dimensional model representing a human skull was used. This model was constructed with different birefringent materials to simulate bone, teeth, and periodontal membranes. Three different vectors of force were applied representing high-, medium-, and low-pull headgear, which were placed at angles of 40, 20, and 0 degrees to the occlusal plane. The photoelastic analysis was made by means of a circular-transmission polariscope arrangement, and the photoelastic data were recorded photographically. The stress areas created by the three different vectors of force were associated with various degrees of canine tipping. This effect was greater with the low-pull force component than with the medium-pull traction. The high-pull headgear produced the least tipping tendency, being closer to a bodily movement effect. Further, stresses were transmitted to deeper structures of the simulated facial bones; these regions were the frontozygomatic, zygomaticomaxillary, and zygomaticotemporal sutures.

A roentgenographic cephalometric evaluation of anchorage management in maximum anchorage cases: By Albert H. Guay, D.M.D. and Robert W. Baker, D.D.S., M.S., Eastman Dental Center, Rochester, N. Y.

A roentgenographic cephalometric evaluation of anchorage management in maximum anchorage cases: By Albert H. Guay, D.M.D. and Robert W. Baker, D.D.S., M.S., Eastman Dental Center, Rochester, N. Y.

A study of sutural facial growth by means of metallic implants in the Macaca rhesus monkey: By Benjamin J. Gans and Bernard G. Sarnat, University of Illinois College of Dentistry, Department of Oral and Maxillofacial Surgery, Chicago, Ill.

Several methods have been described for accomplishing distal movement of canines without losing posterior anchorage. An accepted method in canine retraction is the use of headgear with J hooks. Since it incorporates extraoral anchorage, it is most effective in maximum-anchorage cases. It was the purpose of this study to analyze the distribution of force transmitted to the alveolus and surrounding structures by means of photoelastic visualization, utilizing J hook headgear for maxillary canine retraction. A three-dimensional model representing a human skull was used. This model was constructed with different birefringent materials to simulate bone, teeth, and periodontal membranes. Three different vectors of force were applied representing high-, medium-, and low-pull headgear, which were placed at angles of 40, 20, and 0 degrees to the occlusal plane. The photoelastic analysis was made by means of a circular-transmission polariscope arrangement, and the photoelastic data were recorded photographically. The stress areas created by the three different vectors of force were associated with various degrees of canine tipping. This effect was greater with the low-pull force component than with the medium-pull traction. The high-pull headgear produced the least tipping tendency, being closer to a bodily movement effect. Further, stresses were transmitted to deeper structures of the simulated facial bones; these regions were the frontozygomatic, zygomaticomaxillary, and zygomaticotemporal sutures.