Survival analysis of temporary anchorage devices: A retrospective analysis in a Nigerian orthodontic patient population

OBJECTIVES

Temporary anchorage devices (TADs) are skeletal anchorage devices. They are minimally invasive and placed by the orthodontist to prevent unwanted tooth movement. This study evaluated the survival rate of orthodontic TADs at 6 months. This study also assessed the effect of age, gender, side, site, dental arch of placement, and length of the TADs on its survival rate.

MATERIALS AND METHODS

Ethical approval was obtained from the Health Research Ethics Committee of the hospital. The study sample comprised orthodontic patients who required the placement of TADs during treatment at a private dental facility in Lagos. Data for the study were obtained from the case files of the study subjects and included the subjects' age, gender, date of placement of the TADs, the site, side and arch of placement, the length of the TADs, and the survival rate of 6 months after placement.

RESULTS

We reviewed 90 placed TADs and observed a survival rate of 88.9%. Most TAD failures occurred in the first month of placement (p = 001). There was no observable statistically significant effect of all other variables assessed (age, gender, arch, site, side, or implant length) on the survival rate of the TADs.

CONCLUSIONS

The survival rate of TADs was high. Most TAD failures significantly occurred within one month of placement. There was no significant association between all other clinical variables and orthodontic mini-implant survival.

Temporary Anchorage Devices

Reaction to the force application is observed in the clinical scenarios as anchorage loss, which is the unwanted movement of the teeth. A plethora of approaches have been developed over time in orthodontics to overcome anchorage loss. These approaches are termed anchorage reinforcement procedures. Anchorage loss refers to the unintended movement or shifting of teeth that are intended to remain stable and serve as anchoring points during orthodontic treatment. This loss of stability can occur in various dimensions, including horizontal, vertical, or transverse, and can result in undesired changes to the overall positioning and alignment of teeth. Anchorage can be termed as conventional intraoral anchorage which usually leads to significant anchorage loss. The conventional extraoral anchorage such as headgear suffers from the issue of compliance.

Should Cone-Beam Computed Tomography Be Performed Prior to Orthodontic Miniscrew Placement in the Infrazygomatic Crest Area?-A Systematic Review

There is no unequivocal scientific consensus for the temporary anchorage device (TAD) positioning in the infrazygomatic crest area (IZC). The two principal aims of this systematic review were to assess bone availability in the IZC and to establish both the target site and the need for cone-beam computed tomography (CBCT) prior to miniscrew placement. The study was performed following PRISMA guidelines (PROSPERO: CRD42023411650). The inclusion criteria were: at least 10 patients, three-dimensional radiological examination, and IZC assessment for the TAD placement. ROBINS-I tool and Newcastle-Ottawa Scale were used for quality evaluation. No funding was obtained. The study was based on the information coming from: PubMed, Google Scholar, Web of Science Core Collection, MDPI, Wiley, and Cochrane Libraries. The last search was carried out on 1 August 2023. Fourteen studies were identified for analysis. A narrative synthesis was performed to synthesize the findings of the different studies. Unfortunately, it is not possible to establish the generally recommended target site for IZC TAD placement. The reasons for this are the following: heterogeneity of available studies, inconsistent results, and significant risk of bias. The high variability of bone measurements and the lack of reliable predictors of bone availability justify the use of CBCT for TAD trajectory planning. There is a need for more high-quality studies aiming three-dimensional bone analysis of the IZC.

Occlusal Plane Steepness and Profile Change Following TAD-Based One-Step Retraction on Four-Unit Extraction Cases: A Retrospective Study

BACKGROUND

With the introduction of high-tech appliances, anchorage devices, and improved patient awareness of the risks associated with maxillofacial surgery, treating complex situations with orthodontic treatment has become more difficult in recent years. This study was conducted to demonstrate that orienting the occlusal plane, all the dental, skeletal, and soft tissue parameters, would be improved and to find which of these parameters could be correlated with the steepness of the occlusal plane.

MATERIALS AND METHODS

This was a retrospective study including 40 cephalometric interpretations for patients who were planned for four-unit extractions (20 cephalometric radiographies before treatment and 20 after finishing the treatment). All were treated in the same orthodontic clinic with the same protocol using the McLaughlin-Bennett-Trevisi (MBT) prescription, with 22 slots and one-step retraction following four-unit extraction based on temporary anchorage devices (TADs).

RESULTS

There was no significant change in the canting of the occlusal plane, and it remained relatively stable from 6.31° to 7.55°, while all the soft tissue-related cephalometric measurements were reduced significantly, except the nasolabial angle, as the relation of the upper and lower lip to the esthetic line of Ricketts' (E-Line) was reduced by 2.91 and 2.46°, respectively; furthermore, the angle of convexity was reduced from 10.92° to 9.79°. Besides, the upper incisor display was reduced by 0.38° Conclusions: Both the Frankfort mandibular angle and upper-incisor-to-Frankfort horizontal plane were significant parametric factors associated with profile change after extraction treatment having a positive 0.01-level Pearson association with occlusal plane steepness. Therefore, using the MBT prescription with TAD-based retraction is one of the favorable methods for the management of complex cases.

Orthodontic camouflage treatment of pseudo-Class III malocclusion on skeletal class III Base complicated with canine impaction treated with temporary anchorage devices: A case report

With conventional mechanics to protract the upper posterior teeth for correcting Class III molar relationships, such as intra-arch mechanics, face mask reverse-pull headgear protraction, and interarch Class III elastics, there are some adverse effects, including diminished patient compliance, the possibility of losing anchorage, and extrusion of upper molars and lower incisors with counterclockwise rotation of the occlusal plane. Protraction force should be directed through the center of resistance of the upper posterior teeth to prevent these side effects.

Microbiological Advances in Orthodontics: An Overview and Detailed Analysis of Temporary Anchorage Devices

Dental biofilm is the initiating factor of oral diseases, such as periodontitis and caries. Orthodontic treatment could alter the microbiome structure balance, and increase the risk of such diseases. Furthermore, fixed appliances can induce temporary changes in the microbiome community, and the changes that clear aligners bring are smaller by comparison. Temporary anchorage devices (TADs) are skeletal anchorages that are widely used in orthodontic treatment. Microorganisms affect the occurrence and development of inflammation surrounding TADs. At present, existing researches have verified the existence of plaque biofilm on the surface of TADs, but the formation of plaque biofilm and plaque composition under different stable conditions have not been fully understood. The development of high-throughput sequencing, molecular biology experiments, and metabonomics have provided new research ideas to solve this problem. They can become an effective means to explore the microbiome surrounding TADs.

Effects of Disinfection and Steam Sterilization on the Mechanical Properties of 3D SLA- and DLP-Printed Surgical Guides for Orthodontic Implant Placement

Three-dimensional printed surgical guides increase the precision of orthodontic mini-implant placement. The purpose of this research was to investigate the effects of disinfection and of two types of autoclave sterilization on the mechanical properties of 3D printed surgical guides obtained via the SLA (stereolithography) and DLP (digital light processing) printing methods. A total of 96 standard specimens (48 SLA and 48 DLP) were printed to analyze the tensile and flexural properties of the materials. A total of 80 surgical guide (40 SLA and 40 DLP) specimens from each printing method were classified into four groups: CG (control group); G1, disinfected with 4% Gigasept (Gigasept Instru AF; Schülke & Mayer Gmbh, Norderstedt, Germany); G2, autoclave-sterilized (121 °C); and G3, autoclave-sterilized (134 °C). Significant differences in the maximum compressive load were determined between the groups comprising the DLP-(p < 0.001) and the SLA- (p < 0.001) printed surgical guides. Groups G2 (p = 0.001) and G3 (p = 0.029) showed significant parameter modifications compared with the CG. Disinfection with 4% Gigasept (Gigasept Instru AF; Schülke & Mayer Gmbh, Norderstedt, Germany) is suitable both for SLA- and DLP-printed surgical guides. Heat sterilization at both 121 °C and 134 °C modified the mechanical properties of the surgical guides.

Influence of the Computer-Aided Static Navigation Technique and Mixed Reality Technology on the Accuracy of the Orthodontic Micro-Screws Placement. An In Vitro Study

To analyze the effect of a computer-aided static navigation technique and mixed reality technology on the accuracy of orthodontic micro-screw placement. Material and methods: Two hundred and seven orthodontic micro-screws were placed using either a computer-aided static navigation technique (NAV), a mixed reality device (MR), or a conventional freehand technique (FHT). Accuracy across different dental sectors was also analyzed. CBCT and intraoral scans were taken both prior to and following orthodontic micro-screw placement. The deviation angle and horizontal deviation were then analyzed; these measurements were taken at the coronal entry point and apical endpoint between the planned and performed orthodontic micro-screws. In addition, any complications resulting from micro-screw placement, such as spot perforations, were also analyzed across all dental sectors. Results: The statistical analysis showed significant differences between study groups with regard to the coronal entry-point (p < 0.001). The NAV study group showed statistically significant differences from the FHT (p < 0.001) and MR study groups (p < 0.001) at the apical end-point (p < 0.001), and the FHT group found significant differences from the angular deviations of the NAV (p < 0.001) and MR study groups deviations (p = 0.0011). Different dental sectors also differed significantly. (p < 0.001) Additionally, twelve root perforations were observed in the FHT group, while there were no root perforations in the NAV group. Conclusions: Computer-aided static navigation technique enable more accurate orthodontic micro-screw placement and fewer intraoperative complications when compared with the mixed reality technology and conventional freehand techniques.

Influence of the Computer-Aided Static Navigation Technique on the Accuracy of the Orthodontic Micro-Screws Placement: An In Vitro Study

To analyze the influence of the computer-aided static navigation technique on the accuracy of placement of orthodontic micro-screws. One hundred and thirty-eight orthodontic micro-screws were randomly assigned to the following study groups: Group A. orthodontic micro-screw placement using a computer-aided static navigation technique (n = 69); B. orthodontic micro-screw placement using the conventional freehand technique (n = 69). In addition, the accuracy in the canine–premolar, premolar and molar sectors was analyzed in each study group. Cone-beam computed tomography and intraoral scans were taken both prior and subsequent to orthodontic micro-screw placement. The images were then uploaded using a 3D implant planning software, where the deviation and horizontal angles were analyzed using a multivariate linear model. These measurements were taken at the coronal entry point and apical endpoint between the planned orthodontic micro-screws. In addition, any complications resulting from micro-screw placement, such as spot perforations, were also analyzed in all dental sectors. The statistical analysis showed significant differences between the two study groups with regard to the coronal entry-point, apical end-point (p < 0.001) and angular deviations (p < 0.001) between the computer-aided static navigation technique and freehand technique study groups. Moreover, statistically significant differences were showed between the different dental sectors (p < 0.001). Additionally, twelve root perforations were observed at the conventional free hand technique study group while there were no root perforations in the computer-aided static navigation technique study group. The results showed that the computer-aided static navigation technique enables a more accurate orthodontic micro-screw placement with less intraoperative complications when compared with the conventional freehand technique.

Comparative Evaluation of Primary Stability of Two Different Types of Orthodontic Mini-Implants

Background

The mini-implants introduced new possibilities of adequate anchorage in orthodontics. Furthermore, due to its small size, it can even be placed at relatively difficult sites with ease. Removal torque should be high to prevent implant unscrewing.

Objective

This prospective clinical trial was aimed to evaluate the insertion torque and removal torque of single-threaded and double-threaded cylindrical orthodontic mini-implants.

Materials and Methods

A total of 36 cases were randomly divided into two groups, with an equal number of patients in each group (n = 18). In Group 1 single-threaded cylindrical mini-implant was placed, and in the other group, cylindrical implants with double-threaded were placed. Maximum insertion torque (MIT) and maximum removal torques (MRTs) were recorded for both groups. Data collected were subjected to statistical analysis.

Results

MIT was found to be significantly higher than MRT for both the groups and between the groups. Intergroup comparison in the present study showed significantly higher values for MIT than MRT. Intergroup comparison of MIT showed more values for Group 2 as compared to Group 1. Similar statistically significant values were seen in terms with MRT, where double-threaded cylindrical mini-implants had more torque value than the other group.

Conclusions

Orthodontic mini screws represent effective temporary anchorage devices. Double-threaded cylindrical mini-implants have significantly higher insertion and removal torque than single-threaded mini-implants and hence better stability.

Skeletal and dental effects of Herbst appliance anchored with temporary anchorage devices: A systematic review with meta-analysis

BACKGROUND

The aim was to evaluate the efficiency of using temporary anchorage devices (TADs) in minimizing the anchorage loss and increasing the skeletal effects during correction of Class II malocclusion with Herbst appliance.

MATERIALS AND METHODS

Search without restrictions was performed up to January 2021 in three electronic databases (CENTRAL, MEDLINE and EMBASE) for randomized controlled trials (RCTs), prospective and retrospective cohort studies. The included studies assessed the dental and skeletal changes in Class II malocclusion patients who were treated using Herbst appliance with or without TADs. The strength of evidence was ranked using GRADE.

RESULTS

Fifty-five records were initially retrieved. A total of 6 studies with 198 patients were finally considered. 4 studies were included in the meta-analysis. The meta-analysis showed that using TADs with acrylic splint Herbst appliance was effective in controlling the inclination of mandibular incisors by a mean difference of -5.49 degrees (95% C.I [-7.36, -3.63], P < .001) when compared to Herbst appliance alone. The results showed also that incorporating TADs with Herbst treatment resulted in greater mandibular skeletal effects including increasing mandibular bone base length by mean difference of 2.22 mm (95% C.I [0.82. 3.61], P = .002) and mandibular length by mean difference of 3.7 mm (95% C.I [1.55, 5.85], P < .001) when compared to Herbst appliance alone.

CONCLUSIONS

Based on a very low level of confidence, it seems that incorporating TADs during orthodontic treatment with Herbst appliance results in minimizing the anchorage loss and increasing the skeletal effects of Herbst appliance during correction of Class II malocclusion.

Orthodontic Intrusion Using Temporary Anchorage Devices Compared to Other Orthodontic Intrusion Methods: A Systematic Review

Objective

To systemically review all clinical trials that evaluate the effectiveness of orthodontic intrusion using bone anchorage devices versus using other orthodontic techniques in adult patients.

Material and Methods

All randomized, controlled clinical trials and prospective studies that compare the use of TADs in intrusion versus alternative devices from the year 2000 to 2019 were searched using various electronic databases. Databases used include Pubmed, Cochrane, Scopus, Lilacs, and ScienceDirect. Selection was initially made by reading the titles and abstracts of potential suitable studies. The final selection was made after reading the full retrieved articles. A methodological score developed by Lagravère was used to assess the quality of evidence. The selection process was illustrated using a PRISMA flow chart.

Results

A total of 3942 articles were retrieved, from which only two randomized clinical trials met the inclusion criteria. This presented a low to medium level of evidence to support the hypothesis that TADs are more effective than other orthodontic intrusion techniques for intruding upper incisors and improving upper incisor to lip relation while eliminating the adverse effect of compromising vertical posterior anchorage. Shorter treatment times and less root resorption were found in the TAD group.

Conclusion

There is insufficient evidence to state that TADs can be used as orthodontic anchorage to effectively intrude the incisors without the need for patient cooperation. Future high quality prospective randomized clinical trials are required.

Efficient Distalization of Maxillary Molars with Temporary Anchorage Devices for the Treatment of Class II Malocclusion

Treatment of Class II malocclusion often requires maxillary molar distalization. However, when applying distalization forces on the maxillary molars, anchorage loss may occur in different degrees not only during molar distalization (such as distal tipping of maxillary molars and mesial movement and proclination of the anterior teeth) but also during the subsequent stage of anterior teeth retraction (such as mesial movement of maxillary molars). All these movements are considered as unwanted side effects, which diminish the clinical effectiveness of distalization. Miniscrew implants can be used as temporary anchorage devices (TADs) to enhance anchorage and, if properly used, to counterbalance the side effects. Among the different available systems, the TAD-supported amda® can be considered as a simple, noncompliant, minimally invasive, and very efficient approach that can be used for the comprehensive treatment of patients with Class II malocclusion not only to distalize the maxillary molars bodily without or with minimal distal tipping and without proclination of the anterior teeth but also in combination with full-fixed appliances to retract and intrude the anterior teeth.

Comparison of the Anchorage Value of the First Molars Supported with Implant and First Molars Supported with Second Molar during En Masse Retraction

Aims and Objectives:

The aim of this study was to determine the efficacy of mini-implants as adjuncts for intraoral anchorage units for en masse retraction of maxillary anterior teeth in bimaxillary dentoalveolar protrusion cases.

Materials and Methods:

The study sample consisted of 15 patients (10 females and 5 males). The samples were compared for anchorage loss with the implant-supported molar and conventional molar contralaterally in both the maxilla and mandible after six months of retraction period. The mini-implants used were 1.5 mm in diameter and 8 mm in length and were inserted in the first and third quadrant between the roots of second premolar and first molar under local anesthesia at an angle of 45°. For en masse retraction, active tiebacks with ligating (100g) were used bilaterally extending from molar hooks to J-hook on a 0.019” × 0.025” stainless steel arch wire. Lateral cephalograms were taken before and after retraction for assessing the loss of anchorage in maxillary and mandibular first molars.

Results:

Anchorage loss of 1.46 mm in the maxilla and 1.36 mm in mandible was found with conventional molar anchorage, whereas no statistically significant anchorage loss was found in the implant-supported molar side.

Conclusion:

Implant-supported molar side showed better anchorage compared with the conventional molar side. Hence, implant-supported molar can be used as an absolute anchorage unit in the en masse retraction of anterior teeth.

Dynamics of alveolar bone healing after the removal of orthodontic temporary anchorage devices

OBJECTIVE

The aim of this study was to investigate the dynamics of alveolar bone formation and healing pattern after the removal of orthodontic temporary anchorage devices (TADs).

METHODS

Miniscrews (N = 32) were inserted into the buccal inter-radicular alveolar bone in beagle dogs. Afterward, miniscrews were removed at different time points during a 13-week period and six different in vivo fluorescent markers were injected at 1, 2, 6, 8, 10, and 12 weeks. Serial changes in bone apposition at the removal and intact control sites were evaluated using μCT, histology, and bone histomorphometry.

RESULTS

Gradual bone apposition at the TAD removal site was noted with bone volume/tissue volume (BV/TV) reaching the level of the control alveolar bone by 7 weeks. Histologically, newly formed woven bone was detected within the removal site which was distinct from the surrounding pre-existing alveolar bone at 13 weeks. Accelerated mineral apposition rate (MAR) and bone formation rate (BFR) were noted between 2 and 6 weeks in the removal site (P < 0.05). Although MAR and BFR gradually decreased after its peak at 2-4 weeks, BFR in the removal site was still higher than the control site at 10-12 weeks (P < 0.05).

CONCLUSIONS

Spontaneous bone healing was noted after TAD removal with regional acceleration of MAR and BFR within 2-6 weeks. However, the removal site was mainly filled with woven bone even after 13 weeks, suggesting a longer healing period is required for the quality of the alveolar bone to reach levels comparable to the surrounding alveolar bone.

Long-term follow-up and treatment of a patient with severe skeletal open bite using temporary anchorage devices

This case report presents the treatment and long-term follow-up of a patient with severe skeletal hyperdivergent open bite, Class II malocclusion, and a severely retruded chin. After failure of early treatment using high-pull headgear with a bite block during the early permanent dentition stage due to an unfavorable growth pattern, orthognathic surgery was proposed but rejected by the patient. Then, temporary anchorage devices were used to correct the occlusion and establish an acceptable overbite and overjet. The overall observation time was 8.5 years; the treatment time using fixed appliances was 3 years and 4 months. The achieved tooth position and occlusal relationship remained stable 2.5 years later without recurrence of the open bite.

Evaluation of Long-term Stability of Vertical Control in Hyperdivergent Patients Treated with Temporary Anchorage Devices

This study aims to evaluate the long-term stability of vertical control in hyperdivergent patients treated with temporary anchorage devices. The sample included 20 hyperdivergent patients without anterior open bite. The temporary anchorage devices were used to intrude the upper incisor and molars for vertical control. Lateral cephalograms were established prior to treatment, immediately after treatment, and during retention. The upper molars and incisors were intruded by 1.33 mm and 1.41 mm after treatment (P<0.05). U6-PP increased by 0.11 mm and 0.23 mm during the first and second stages of retention (P>0.05). U1-PP was found to possess a significant extrusion of 1.2 mm during the first stage (P<0.05), which increased by 0.68 mm during the second stage (P>0.05). The mandibular plane angle (MP-SN) decreased by 2.58 degrees following treatment, and underwent a relapse of 0.51 degree and 0.42 degree during the first and second stages of retention respectively (P>0.05). No significant soft tissue changes occurred, with the exception of increased upper lip length during the second stage (P<0.05). Maxillary anterior and posterior intrusions, counter clockwise rotation of the mandibular plane, and improved profiles can be successfully achieved following treatment with vertical control. During the first stage of retention (less than three years), intruded molars and incisors both exhibited some extrusion, and molars had better long-term stability than incisors. During the second stage of retention (three to six years), the therapeutic effects appeared stable, with the exception of some increase in upper lip length. Rotated mandibular plane remained stable during the entire retention period.

Cementum and dentin repair following root damage caused by the insertion of self-tapping and self-drilling miniscrews

OBJECTIVE:

The aim of this study was to evaluate the histological responses of cementum, root dentin, and pulp following intentional root injuries caused via self-tapping and self-drilling miniscrews.

MATERIALS AND METHODS:

Fourteen patients (with a mean age of 15.7 years and age range of 14–18 years) who were scheduled for the extraction of all four first premolars as part of their orthodontic treatment plan participated in this study. The roots of the right and the left quadrants' first premolars were designedly injured using self-tapping miniscrews and self-drilling miniscrews, respectively. Teeth were extracted eight weeks after the injury. Cementum repair was assessed through histological examinations.

RESULTS:

In this study, 40 teeth (75.4%) showed reparative cementum formation and 13 teeth (24.5%) showed no repair. There was no significant difference between the two groups regarding the formation of reparative cementum (P = 0.3). In all examined teeth, the inflammatory response of the pulp to the cold test was within the normal range.

CONCLUSION:

This study showed that in most cases, the healing of cementum was observed eight weeks after the injury and the two methods of miniscrew insertion showed no significant difference when it comes to the healing process.

Controlling the vector of distraction osteogenesis in the management of obstructive sleep apnea

Background:

Obstructive sleep apnea (OSA) in individuals with craniofacial anomalies can compromise airway and is a serious life-threatening condition. In many cases, tracheostomy is carried out as the treatment of choice. Distraction osteogenesis of the mandible as a treatment modality for OSA is very useful and may spare the need for tracheostomy or allow decannulation, yet controlling the vector of distraction is still a major challenge. We present a method for controlling the vector of distraction.

Materials and Methods:

Eight patients with severe respiratory distress secondary to a micrognathic mandible were treated by mandibular distraction osteogenesis using either external or internal devices. Temporary anchorage devices (TADs) and orthodontic elastics were used to control the vector of distraction. Cephalometric X-rays, computed tomography, and polysomnographic sleep studies were used to analyze the results.

Results:

A mean distraction of 22 mm using the internal devices and a mean of 30 mm using the external devices were achieved. Increase in the pharyngeal airway and hyoid bone advancement was also observed. Anterior-posterior advancement of the mandible was noted with no clockwise rotation. Most importantly, clinical improvement in symptoms of OSA, respiratory distress, and feeding was noted.

Conclusions:

We describe a method for controlling the vector of distraction used as a treatment for OSA. In these cases, TADs were used as an anchorage unit to control the vector of distraction. Our results show excellent clinical and radiographical results. TADs are a simple and nonexpensive method to control the vector of distraction.

Comparison of temporary anchorage devices and transpalatal arch-mediated anchorage reinforcement during canine retraction

Objective:

The purpose of this study was to compare the dental and skeletal effects of canine retraction using conventional anchorage reinforcement systems and comparing them with the usage of TADs.

Materials and Methods:

The sample consisted of 50 patients having Class I malocclusions with bimaxillary protrusion indicated for first premolar extraction, and allocated into two groups. The first group consisted of 25 patients with a mean age of 18,7 years (min:14, max:22 years, 16 girls and 9 boys) that TADs were applied as an anchorage mechanic between attached gingiva of upper second premolar and first molar teeth. The second group consisted of 25 patients with a mean age of 19,4 years (min:15, max:23 years, 14 girls and 11 boys) that conventional molar anchorage with Transpalatal arch (TPA) was applied for the anchorage mechanics against canine retraction.

Results:

The results showed that mean mesial movement and the tipping of the first molars in TAD group between T0 - T1 were insignificant (P > 0,05), however in the TPA group were significant (P<0,01). Vertical movement of the molars were not significant when two groups were compared (P>0,05).

Conclusion:

Although TPA is a useful appliance, it doesn't provide an effective anchorage control on anteroposterior movement maxillary first molar teeth concerning first premolar extraction treatment. TADs are more convenient to provide absolute anchorage during maxillary canine retraction in contrast to transpalatal arch.

Distalization of maxillary arch and correction of Class II with mini-implants: A report of two cases

This article reports the successful use of mini-screws in the maxilla to treat two patients of age 21-year and 17-year-old girls. Both the patients had a skeletal Class II malocclusion with protrusive maxillary teeth and angels Class II mal-occlusion. Temporary anchorage devices (TADs) in the posterior dental region between maxillary second premolar and maxillary first molar teeth on both sides were used as anchorage for the retraction and intrusion of her maxillary anterior teeth. Those appliances, combined with a compensatory curved maxillary archwire, eliminated spacing, deep bite, forwardly placed and proclined upper front teeth and the protrusive profile, corrected the molar relationship from Class II to Class I. With no extra TADs in the anterior region for intrusion, the treatment was workable and simple. The patient received a satisfactory occlusion and an attractive smile. This technique requires minimal compliance and is particularly useful for correcting Class II patients with protrusive maxillary front teeth and dental deep bite.

Management of post midface distraction occlusal discrepancy using temporary anchorage devices in a cleft patient

Open bite deformity following a successful midface advancement by distraction osteogenesis is a common complication. Temporary anchorage devices can be deployed during the distraction and post-distraction settling phases for restoring the occlusion even in severe cases. The following report describes the management of severe anterior open bite following maxillary distraction.

Clinical application of micro-implant anchorage in initial orthodontic retraction

Micro-implant is a device that is temporarily fixed to bone for the purpose of enhancing orthodontic anchorage either by supporting the teeth of the reactive unit or by obviating the need for the reactive unit altogether, and which is subsequently removed after use. The purpose of this study was to evaluate the clinical efficiency of micro-implants in reinforcing anchorage during the initial retraction of anterior teeth, check the rate of initial retraction for 8 weeks, and assess the stability of micro-implants during this period. Eighteen micro-implants were placed (10 in the maxilla and 8 in the mandible) and immediately loaded with 200-250 g of force using 9-mm closed coil Nitinol springs. The amount of space closure was measured every 2 weeks until the eighth week. Cephalometric measurements were made at the end of the study to evaluate anchor loss, if any. Micro-implant stability was also assessed. The rate of initial retraction in the maxilla at the end of 8 weeks was 1.65 mm/quadrant and 1.51 mm/quadrant in the mandible. The amount of retraction on the left side of the arches was 1.66 mm/quadrant and 1.49 mm/quadrant on the right side. The average initial retraction for both arches per month was 0.78 mm. An anchor loss of 0.1 mm (0.06%) was observed in the maxilla while no mandibular anchor loss was recorded. The rate of initial retraction observed in the maxilla was more than that achieved in the mandible. Initial retraction was also more on the left side of the arches. There was no anchor loss in the mandible. The micro-implant-reinforced anchorage was helpful in minimizing anchor loss and accepted heavy traction forces but did not bring about a faster rate of retraction.