Placement Of Temporary Anchorage Devices Research Articles

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

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. 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. 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. 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.

Maxillary sinus dimensions in skeletal class II population with different vertical skeletal patterns.

The location of the maxillary sinus significantly affects the orthodontic treatment, particularly when temporary anchorage devices (TADs) are taking place. The current study aims to evaluate the maxillary sinus size and location in a skeletal class II population. The pre-orthodontic treatment CBCT images of the skeletal class II population were selected. The sinus's volumetric size, height, width, and depth were measured and compared among different skeletal vertical patterns and between genders. In addition, the height and width of the alveolar bone surrounding the maxillary sinus floor were quantified in the same manner. Patients who displayed a high-angle skeletal pattern had significantly greater maxillary sinus dimensions, shorter vertical distance between the maxillary sinus floor and the alveolar bone crest, and thinner alveolar bone surrounding the maxillary sinus. Meanwhile, the maxillary sinus dimension measurements were positively correlated with the SN-MP angle in both genders but only correlated with ANB angle in females. On the other hand, the vertical distance between the maxillary sinus floor and the alveolar bone crest was negatively correlated with the SN-MP angle in males but the ANB angle in females. In the skeletal class II population, the high-angle patients faced a higher risk of maxillary sinus perforations by TADs. In addition, gender-related variations were noticed warranting clinical attention, as males have a higher potential for maxillary sinus penetration from TAD placement than females. Maxillary posterior alveolar TADs are often prescribed to achieve the distalization of maxillary posterior teeth in class II patients. The current study provided more insight into the "safe zone" for TAD placement related to the maxillary sinus.

Evaluation of total bone and cortical bone thickness of the palate for temporary anchorage device insertion

Background/purposeThe palate has become a popular site for the placement of temporary anchorage devices (TADs) owing to its bone quantity and quality. This study aimed to investigate total and cortical bone thicknesses in the whole palate as well as palatal width using a standard grid system and cone-bean computed tomography (CBCT) images. Materials and methodsThe CBCT images of 43 samples were selected. The total bone and cortical bone thicknesses of the palate were surveyed on 64 points per patient. The palatal width was measured. The difference between the age and sex groups was analyzed. ResultsThe total palatal bone thickness in the adult group ranged from 9.85 ± 2.04 to 1.87 ± 0.79 mm. In the adolescent group, we found one-third of the incisor roots in the area 3 mm distal to the incisive foramen and 8 mm lateral to the mid-palatal suture. The cortical bone thickness in adults was significantly thicker in the posterior paramedian area than that in adolescents. ConclusionThe thickest vertical bone is located in the zone 3 mm distal to the incisive foramen and 4–8 mm lateral to the midpalate. The zone 6 mm posterior to the incisive foramen and 2–8 mm lateral to the midpalate exhibited optimal thickness and was away from the incisor roots. This region could be a safe zone for adolescent patients to place TADs. When TADs are to be inserted at the posterior palate, the 2-mm paramedian area should be the first region of choice.

Orthodontic and Surgical Principles for Distraction Osteogenesis in Children with Pierre-Robin Sequence.

Patients with Pierre-Robin sequence recalcitrant to nonsurgical intervention have historically required tracheostomy. Mandibular distraction provides a predictable alternative to tracheostomy. Orthodontic perioperative interventions should be considered, including overcorrection, placement of temporary anchorage devices, elastics, and molding the regenerate. Mandibular distraction can be technically difficult and may cause complications. Performed correctly, mandibular distraction provides patients with a better quality of life than tracheostomy.

Tomographic evaluation of infrazygomatic crest for orthodontic anchorage in different vertical and sagittal skeletal patterns.

BackgroundAnalysis of the anatomy of the region during preoperative planning is very important in order to minimize the risks of undesired movements in the supporting teeth or even damage to important structures such as the maxillary sinus. To the best of our knowledge, no study evaluated the relationship of these skeletal patterns with the anatomy of the infrazygomatic crest. The aim of this study was to evaluate the tomographic measurements of the infrazygomatic crest for placement of temporary anchorage devices in individuals with different vertical and sagittal skeletal patterns. Material and MethodsThe measurements were analyzed in three regions in the crest of 67 patients above the maxillary first molar: A slice in the long axis of the mesiobuccal root, a slice passing through the center of the furcation area of the tooth, and another slice in the long axis of the distobuccal root. In each of these slices five measurements of the thickness of the infrazygomatic crest were performed, with a difference of 1 mm between them. The sagittal skeletal pattern was determined by the ANB angle and the vertical skeletal pattern by the SN.GoGn angle. ResultsThe bone thickness of the crest tended to decrease gradually in the apical direction. There was no difference between different vertical and sagittal skeletal patterns. ConclusionsThe individual parameters did not have significant influence in the thickness of the infrazygomatic crest. Key words:Tomography, X-Ray Computed, orthodontics, mini-implant, infrazygomatic crest, maxilla.

Influence of vertical skeletal pattern on cortical and alveolar bone thickness and root spacing in the anterior maxilla assessed by cone beam computed tomography

PurposeThe aim of this study was to evaluate the dimensional properties of bone in the anterior maxilla in patients with different vertical skeletal patterns in order to ensure safe placement of temporary anchorage devices. Materials and methodsFifty-one CBCT images were divided into three equal groups according to vertical skeletal pattern, based on palatal plane to mandibular plane angle. Cortical bone thickness, alveolar bone thickness and interdental root distance were measured between the teeth in the anterior maxilla at 6 mm and 8 mm apical to the interdental cementoenamel junction. ResultsCortical bone thickness was significantly different among vertical groups at some sites. Hyper-divergent subjects had thinner cortical bone than hypo-divergent and normo-divergent subjects. All three groups, in the anterior maxilla, cortical bone thickness tended to increase from between central incisors (U1–U1) to between lateral incisor and canine (U2–U3). Alveolar bone thickness was greatest between central and lateral incisors (U1–U2), and the thinnest alveolar bone was at U1–U1 area. Average interdental root distance ranged from 1.33 ± 0.48 mm to 3.43 ± 1.25 mm. The largest and smallest interdental root distances were at U1–U1 and U1–U2 sites, respectively. ConclusionPlacement of TADs in hyper-divergent subjects should be performed with caution. The suitable site for TADs in the anterior maxilla was between the lateral incisor and canine in all vertical skeletal patterns.

Treatment of VME using extra-alveolar TADs: Quantification of treatment effects

Introduction: Temporary anchorage devices (TADs) have been shown to be effective in the treatment of VME and/or bimaxillary protrusion but literature focus has been on maxillary miniscrews and not on the efficacy of mandibular TADs. In the present study, orthodontic extraction therapy was combined with maxillary extra-alveolar TADs in the treatment of all VME patient-subjects. The purpose was to investigate how various combinations of mandibular anterior and/or posterior extra-alveolar implants affected VME correction. The null hypothesis was no difference in treatment effects relative to mandibular TAD placement strategy. Methods: Sixty-nine VME, bimaxillary protrusive, smile patients were grouped according to mandibular extra-alveolar TAD placement configuration; soft and hard tissue treatment effects were evaluated using a cephalometric analysis comprised of 24 measurements. Results: (1) Posterior miniscrew anchorage provided favorable horizontal anchorage control with maximal, non-compliance retraction of upper anterior teeth. (2) Soft tissue profile changes secondary to maximum anterior retraction resulted in the greatest amount of lip retraction reported in the literature to date. (3) Combined use of posterior and anterior miniscrews provides favorable vertical control with counterclockwise mandibular rotation and posterior facial height reduction for hyperdivergent patients. (4) The anchorage configuration based upon combining posterior and anterior extra-alveolar TADs is effective in the treatment of VME patients with bimaxillary protrusion and gummy smile.

Quantitative evaluation of palatal bone thickness in patients with normal and open vertical skeletal configurations using cone-beam computed tomography.

PurposeTo perform a comparative analysis of the palatal bone thickness in Thai patients exhibiting class I malocclusion according to whether they exhibited a normal or open vertical skeletal configuration using cone-beam computed tomography (CBCT).Materials and MethodsThirty CBCT images of Thai orthodontic patients (15–30 years of age) exhibiting class I malocclusion with a normal or open vertical skeletal configuration were selected. Palatal bone thickness was measured in a 3.0-mm grid pattern on both the right and left sides. The palatal bone thickness of the normal-bite and open-bite groups was compared using the independent t-test. The level of significance was established at P<.05.ResultsThe palatal bone thickness in the normal-bite group ranged from 2.2±1.0 mm to 12.6±4.1 mm. The palatal bone thickness in the open-bite group ranged from 1.9±1.1 mm to 13.2±2.3 mm. The palatal bone thickness was lower at almost all sites in patients with open bite than in those with normal bite. Significant differences were found at almost all anteroposterior sites along the 3 most medial sections (3.0, 6.0, and 9.0 mm lateral to the midsagittal plane) (P<.05).ConclusionClass I malocclusion with open vertical skeletal configuration may affect palatal bone thickness, so the placement of temporary anchorage devices or miniscrew implants in the palatal area in such patients should be performed with caution.

Modified Surgical Stent for Accurate TAD Placement.

The development of temporary anchorage devices (TADs) has allowed for the creation of anchorage in situations where there once was none. Many studies have suggested that the most significant cause of miniscrew failure is insufficient distance between the surface of a root and the miniscrew. In order to reduce the miniscrew failure rate, a modified surgical stent has been shown to not only increase TAD insertion accuracy but also to increase TAD success rates.

The nasopalatine canal, a limiting factor for temporary anchorage devices: a cone beam computed tomography data study.

There is only little knowledge on topographical predispositions of the nasopalatine canal as a limiting factor for insertion of mid-palatal temporary anchorage devices (TAD). The purpose of the study was to assess the course of the nasopalatine canal, the adjacent vertical bone quantity, and whether it might differ among vertical facial types, using pre-existing cone beam computed tomography (CBCT) scans. Out of a consecutive sample collected from April 2008 to August 2012, only patient data depicting both upper and lower jaw completely were evaluated retrospectively. The linear measurements were taken on the respective midsagittal view perpendicular to the palate at the level of 1st molar/2nd premolar (5/6), 2nd premolar/1st premolar (4/5), and 1st premolar/canine (3/4). Screen-prints were used to measure the inclination of the nasopalatine canal in relation to the maxillary jaw base. Maxillary and mandibular divergence was assessed on rendered lateral cephalograms. Out of 3869 pre-existing consecutive CBCT scans, data from 398 patients met the inclusion criteria and could be extracted. The mean vertical bone was 4.09 mm at the 5/6 level, 5.22 mm at the 4/5 level, and 3.14 mm at the 3/4 level, respectively. A statistically significant negative correlation exists between jaw divergence and the canal angulation with regard to the maxillary base. A statistically significant negative correlation exists between the canal angulation and vertical bone measurements at the 4/5 and 3/4 levels. Vertical bone volume is sufficient at 4/5 level for TAD placement, and bares only a small risk for neuro-sensory impairment. Therefore, only in rare cases a CBCT is justified for palatal implant placement. The course of the nasopalatine canal is negatively correlated with the vertical skeletal facial pattern pointing to the fact that in hypodivergent patients a TAD might be placed in a more distal or paramedian region.

A custom made grid to guide placement of temporary anchorage devices

The use of implant anchorage has simplified orthodontic treatment by sparing us the need for patient compliance and the complexity of treatment. One of the most important factors affecting the success of interdental implants is preventing the damage to adjacent roots and periodontal ligament. The most common causes of root damage from mini-implant insertion are improper site selection and an inaccurate angle of drill penetration. We thereby present a custom made modified grid help in more accurate placement of temporary anchorage devices and guide the angle of drill penetration. The grid can be placed anywhere in the oral cavity (buccally, palatally, anteriorly or posteriorly) and it can be attached to the main arch wire, bracket or even on unbounded teeth. The measuring reference grid with two vertical guide arms is connected with a horizontal arm that will later be secured to the adjacent bracket at both ends. The grid includes small squares, which effectively upgrade the efficiency during the orthodontic implant placement. The two vertical guide arms help in maintaining the desired angulation while drilling indicating the mesial and distal root surface of the adjacent teeth.

Closure of an open bite using the ‘Mousetrap’ appliance: a 3-year follow-up

AbstractRecently, skeletal anchorage devices have been used as anchorage units for upper molar intrusion as a way of correcting an anterior open bite malocclusion. To avoid the surgical procedures associated with the placement of miniplates in the zygomatic area, mini-implants may be inserted palatally or buccally in the alveolar process. However, consideration must be given to the potential risks of root damage and a higher failure rate associated with the placement of temporary anchorage devices (TADs) in the interradicular area. The anterior hard palate provides a safer and more stable alternative for TAD placement. The current paper describes the biomechanical principles and the clinical procedures of ‘Mousetrap’ mechanics using mini-implants in the anterior palate for upper molar intrusion. The stomatognathic response of maxillary molar intrusion is an autorotation of the mandible and so the sagittal implications for each patient must be considered. The presented patient demonstrates successful correction and stability of the treatment result at a three-year review.

Hard palate thickness for temporary anchorage devices placement: Differences in sex and ethnicity

PurposeThe purpose of this study is to determine variations in hard palate thickness among sexes and four ethnic groups to identify optimum area for temporary anchorage devices (TADs) placement. Materials and methodsCone-beam computed tomography (CBCT) volume data on 160 patients were selected. Patients belonged to one of four ethnic groups (Asian, African-American, Caucasian or Hispanic; 20 men and 20 women in each group, 16–45 years old). Hard palate thickness from the incisor fossa to the palatal root of the maxillary first molar was determined on each image and compared between sexes and ethnic groups. ResultsThe data revealed that thickness was greatest at the paramedian area in the incisive canal zone (C-zone) and the median area posterior to the incisive foramen. A significant difference in thickness of palate was confirmed between sexes, and was approximately 0.5mm and 1mm greater in men at the median and paramedian, respectively. Among ethnic groups, a trend of decreasing thickness was as follows: Caucasian>Hispanic>African-American>Asian. ConclusionThe anterior (incisive canal zone) paramedian and posterior median areas of the hard palate were thicker and suggest that these areas are appropriate for TADs placement. Some differences were also observed local to the paramedian in the C-zone among ethnicities. This indicates that sex and ethnicity should be taken into consideration in selecting sites for placement of TADs.

Factors affecting the clinical success of orthodontic anchorage: Experience with 266 temporary anchorage devices

Background/purposeThe purpose of this retrospective study was to evaluate the factors affecting the clinical success of orthodontic anchorage by using temporary anchorage devices (TADs). Materials and methodsOne hundred and twenty nine consecutive patients (54 males, 75 females; mean age, 20.2 years old) with a total of 266 TADs of three different types were examined. The variables related to TAD success were assessed through five categories: implant-related (type 1, type 2, and type 3 with different diameters and lengths), patient-related (sex, age, and type of malocclusion), location-related (jaw, site, side, bone quality, and the type of soft tissue), orthodontic-related (the timing of force application), and implant-maintenance factors (local inflammation around a TAD: mild, moderate, and severe). ResultsThe overall success rates were 97%. The clinical variables of all implant-related factors (diameter and length), all patient-related factors (sex, age, and type of malocclusion), and one of location-related factors (side) did not show any statistically significant difference in success rates. The clinical variables of most location-related factors [jaw (mandible), site (lingual), bone quality (Q4), and the type of soft tissue around TADs (mucosa)], orthodontic-related factors [timing of force application equal to 2 weeks)], and implant-maintenance factors [local inflammation (mild–moderate and moderate–severe)] showed less success with statistically significant differences. ConclusionIn order to improve the success rates, local inflammation should be monitored and controlled, force application should be 4 weeks after insertion, and the location for placement of TADs should be good quality bone with keratinized mucosa.

Evaluation of mandibular cortical bone thickness for placement of temporary anchorage devices (TADs)

ObjectiveIn this study, we measured the cortical bone thickness in the mandibular buccal and lingual areas using computed tomography in order to evaluate the suitability of these areas for application of temporary anchorage devices (TADs) and to suggest a clinical guide for TADs.MethodsThe buccal and lingual cortical bone thickness was measured in 15 men and 15 women. Bone thickness was measured 4 mm apical to the interdental cementoenamel junction between the mandibular canine and the 2nd molar using the transaxial slices in computed tomography images.ResultsThe cortical bone in the mandibular buccal and lingual areas was thicker in men than in women. In men, the mandibular lingual cortical bone was thicker than the buccal cortical bone, except between the 1st and 2nd molars on both sides. In women, the mandibular lingual cortical bone was thicker in all regions when compared to the buccal cortical bone. The mandibular buccal cortical bone thickness increased from the canine to the molars. The mandibular lingual cortical bone was thickest between the 1st and 2nd premolars, followed by the areas between the canine and 1st premolar, between the 2nd premolar and 1st molar, and between the 1st molar and 2nd molar.ConclusionsThere is sufficient cortical bone for TAD applications in the mandibular buccal and lingual areas. This provides the basis and guidelines for the clinical use of TADs in the mandibular buccal and lingual areas.

The effectiveness of Oraqix versus TAC(a) for placement of orthodontic temporary anchorage devices

To test the hypothesis that there is no difference in the actions and effectiveness of topical anesthetics TAC Alternate (TAC((a))) and Oraqix in placing temporary anchorage devices (TADs). Each topical anesthetic was placed on opposing sides in the maxilla or mandible using blinded applicators for 3-9 minutes followed by the TAD placement. A total of 21 patients ranging from 10-25 years old were studied. During the procedure the primary investigator (PI) used the sound, eye, and motor scale to measure the movements elicited by the patient. The PI also noted the time taken for the topical anesthetic to be effective and the amount that was applied. Following the placement of the TADs, the patients were given the Wong-Baker FACES Scale and the Visual Analog Scale to rate the degree of discomfort. The nonparametric Wilcoxon signed-rank test was used to test the effectiveness of the treatments based on the three ordinal scales, the dosage, and the onset time. The time it took for the TAC((a)) to provide adequate anesthesia averaged 4.43 minutes and for Oraqix the time was 6.33 minutes (P = .00). The minimum dosage of TAC((a)) to provide adequate anesthesia averaged 0.25 mL, and for Oraqix the minimum dosage averaged 0.31 mL (P = .00). The hypothesis was rejected. TAC((a)) was more effective than Oraqix in placing TADs with a recommended dose of 0.20-0.30 mL and a minimum application time of 3 minutes.

Editor's Summary and Q&A: Retrospective cone-beam computed tomography evaluation of temporary anchorage devices

<h3>Introduction</h3> Miniscrew impants as temporary anchorage devices (TADs) are becoming more popular in orthodontic tretment. Their ease of use allows orthodontists to place them in locations in the mouth that are convenient for orthodontic treatment mechanics. The aims of this study were to evaluate the location of TADs placed during orthodontic treatment and to relate the placement to the surrounding dentoalveolar structures. <h3>Methods</h3> Three-dimensional cone-beam computed tomography scans were taken before and after placement of the TADs over a 6-month period as part of routine clinical protocol. The following parameters were recorded: placement site, length of the TAD in the alveolar bone, amount of contact with the periodontal ligament, and interroot distance between TADs. <h3>Results</h3> Thirty-five TADs (19 in the maxilla, 16 in the mandible) were evaluated. The mean lengths of the TADs in alveolar bone were 5.29 ± 1.39 mm in the maxilla and 4.60 ± 0.86 mm in the mandible. The amounts of contact with the periodontal ligaments were 2.54 ± 0.81 mm (n = 13) in the maxilla and 2.72 ± 0.49 mm (n = 10) in the mandible. The interroot distance measurements were 2.78 ± 0.76 mm (n = 15) and 5.19 ± 4.42 mm (n = 16) in the maxilla and the mandible, respectively. Paired <i>t</i> tests indicated a significant difference in the interroot distance for mandibular teeth. <h3>Conclusions</h3> Three-dimensional cone-beam computed tomography technology allows better visualization of TAD placement. Clinicians can expect 71.2% of the length of the screw section of the TAD to be embedded in the alveolar bone; the percentage is often higher in the maxilla than in the mandible. Of the 35 TADs, 65.2% were in contact with the periodontal ligament. There appears to be more space for TAD placement in the mandible than in the maxilla.

Retrospective cone-beam computed tomography evaluation of temporary anchorage devices

Miniscrew implants as temporary anchorage devices (TADs) are becoming more popular in orthodontic treatment. Their ease of use allows orthodontists to place them in locations in the mouth that are convenient for orthodontic treatment mechanics. The aims of this study were to evaluate the location of TADs placed during orthodontic treatment and to relate the placement to the surrounding dentoalveolar structures. Three-dimensional cone-beam computed tomography scans were taken before and after placement of the TADs over a 6-month period as part of routine clinical protocol. The following parameters were recorded: placement site, length of the TAD in the alveolar bone, amount of contact with the periodontal ligament, and interroot distance between TADs. Thirty-five TADs (19 in the maxilla, 16 in the mandible) were evaluated. The mean lengths of the TADs in alveolar bone were 5.29 +/- 1.39 mm in the maxilla and 4.60 +/- 0.86 mm in the mandible. The amounts of contact with the periodontal ligaments were 2.54 +/- 0.81 mm (n = 13) in the maxilla and 2.72 +/- 0.49 mm (n = 10) in the mandible. The interroot distance measurements were 2.78 +/- 0.76 mm (n = 15) and 5.19 +/- 4.42 mm (n = 16) in the maxilla and the mandible, respectively. Paired t tests indicated a significant difference in the interroot distance for mandibular teeth. Three-dimensional cone-beam computed tomography technology allows better visualization of TAD placement. Clinicians can expect 71.2% of the length of the screw section of the TAD to be embedded in the alveolar bone; the percentage is often higher in the maxilla than in the mandible. Of the 35 TADs, 65.2% were in contact with the periodontal ligament. There appears to be more space for TAD placement in the mandible than in the maxilla.

Sterilization requirements for miniscrew placement

Sterilization requirements for miniscrew placement

CDC weighs in on TADs

This letter is in response to a recent guest editorial (Scholz RP, Cook A. Sterilization requirements for the placement of temporary anchorage devices. Am J Orthod Dentofacial Orthop 2009;l35[4 Suppl]:S20-2). The authors presented information on sterilization procedures for the placement of a particular type of temporary anchorage device (TAD), the miniscrew implant (MSI). We believe that several of the editorial's statements regarding the infection control recommendations of the Centers for Disease Control and Prevention (CDC) are inaccurate and might result in inappropriate or unnecessary precautions by dental health care providers.