Site selection of micro-implant anchorages in the infrazygomatic crest in adult orthodontic patients

OBJECTIVES

To determine the optimal placement of miniscrews, this study compared adult male and female patients in terms of cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest region.

METHODS

The cone beam computed tomography imaging data of 200 patients (20-30 years old; 100 males and 100 females) were collected. The right maxillary posterior teeth in the sagittal plane were divided into six levels from proximal to distal, and three measurement sites were positioned at vertical distances of 8, 10, and 12 mm from the cementum. Cortical bone density, cortical bone thickness, and available bone width were measured in 18 measurement sites in the infrazygomatic crest and analyzed statistically.

RESULTS

The highest cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest in adult male and female patients were at the level of the interradicular space between the maxillary second premolar and maxillary first molar. The bone cortical density and thickness increased with vertical height, whereas the available bone width decreased with increasing vertical height. Differences were observed in cortical bone density, cortical bone thickness, and available bone width between adult male and female patients.

CONCLUSIONS

The optimal implantation sites of the micro-implant anchorages in the infrazygomatic crest were at the level of the interradicular space between the maxillary second premolar and the maxillary first molar, and the vertical height of the optimal implantation site in males was appropriately higher than that in females.

Comprehensive orthodontic treatment using miniscrews and digital rehabilitation in a patient with severe recessive dystrophic epidermolysis bullosa

INTRODUCTION

Epidermolysis bullosa (EB) is a rare genetic disorder characterized by skin fragility and blister formation. The phenotypic presentation is broad with four major types, being Recessive Dystrophic EB (RDEB) the most severe, including oral anomalies such as severe microstomia, ankyloglossia, vestibule obliteration and occlusal anomalies, turning orthodontic treatment into a challenge.

AIM

This case report aims to present the comprehensive treatment of a patient with severe RDEB, including periodontal surgery, orthodontic fixed braces with mini-screws and oral rehabilitation with anterior veneers.

CASE REPORT

A 27-year-old female patient with severe RDEB received orthodontic treatment in the upper jaw to improve malalignment and anterior crossbite. After 13 months of treatment with fixed appliances, miniscrews were placed in the anterior segment to intrude and procline the upper incisors. Oral surgery was performed to increase the vestibule depth of the upper lip. Once edge-to-edge occlusion was obtained, anterior veneers were placed to improve aesthetic and stabilize occlusion, especially with the lack of posterior support.

DISCUSSION

The multidisciplinary treatment approach, involving orthodontic treatment, periodontal surgery and oral rehabilitation, played a crucial role in achieving favorable results. This case highlights the successful use of miniscrews as a viable orthodontic approach for patients with severe RDEB.

Alveolar Bone Microstructure Surrounding Orthodontic Anchor Screws with Plasma Surface Treatment in Rats

A lateral load was applied to anchor screws that had undergone surface treatment, and the structure, cellular dynamics, and quality of the bone surrounding anchor screws were analyzed to investigate the effect of this surface treatment on the peri-implant jawbone. In addition, bone microstructural characteristics were quantitatively evaluated for each site of loading on the bone around the anchor screw. Rats were euthanized after observation on days 3, 5, or 7, and bone quality analyses were performed. Bone-implant contact rate increased more rapidly at an early stage in the treated surface group than in the untreated surface group. Bone lacuna morphometry showed that the measured values adjacent to the screw at the screw neck on the compressed side (A) and at the screw tip on the uncompressed side (D) were significantly lower than those at the screw tip on the compressed side (B) and at the screw neck on the uncompressed side (C). Collagen fiber bundle diameter showed that the measured values adjacent to regions A and D were significantly higher than those at regions B and C. Anchor screw surface activation facilitates initial bone contact of the screw, suggesting that early loading may be possible in clinical practice.

Adjunctive controlled intrusion of the maxillary first molar using orthodontic miniscrews

In the absence of the mandibular first molar, there is corresponding supra-eruption of the maxillary first molar, which can lead to occlusal interferences compromising the space available for restoration with a prosthesis. In this case report, the maxillary left first molar intrusion has been discussed with the use of two miniscrews. A 28-year-old female reported with a missing mandibular left first molar and wanting to replace it with a dental implant. The patient presented with a Class I skeletal relation, mild proclination of the anteriors and occlusal contacts. The maxillary first molar had erupted by >4 mm beyond the occlusal plane, thereby reducing the space available for placement of a lower prosthetic crown. After 5 months of intrusion, the desired occlusal clearance was achieved, and impressions were recorded. For retention, the patient was given an upper clear vacuum retainer and the crown was placed on the implant.

Tooth Complications after Orthodontic Miniscrews Insertion

Orthodontic miniscrews (OM) are widely used in modern orthodontic clinical practice to improve skeletal anchorage and have a high safety profile. A complication at the time of OM insertion is tooth root perforation or periodontal ligament trauma. Rarely, OM injury can cause permanent damage, such as ankylosis, osteosclerosis, and loss of tooth vitality. The aim of this work was to analyze potential risks and dental complications associated with the use of OMs. A search of the PubMed, Cochrane, Web of Science, and Scopus databases was conducted without a time limit using the keywords "orthodontic mini-screw" and "dental damage", resulting in 99 studies. After screening and eligibility, including articles obtained through a citation search, 13 articles were selected. Four studies revealed accidental injuries caused by OM. Most of the damage was localized at the root level and resolved spontaneously with restorative cement formation after prompt removal of the OM, while the pain disappeared. In some cases, irreversible nerve damage, extensive lesions to the dentin-pulp complex, and refractory periapical periodontitis occurred, requiring endodontic and/or surgical treatment. The choice of insertion site was the most important element to be evaluated during the application of OMs.

Clinical advances in maxillary skeletal expansion and introduction of a new MARPE concept

BACKGROUND

Transverse maxillary deficiency, typically characterized by the clinical manifestations of unilateral or bilateral crossbite, is a common orthodontic discrepancy. The primary goal of maxillary expansion should be to obtain a nearly maximum width increase in the basal bone of the constricted maxilla and to avoid the dental expansion of the anchor teeth. The introduction of miniscrew anchorage-supported rapid maxillary expansion (MARPE) devices has helped increase the feasibility of obtaining nonsurgical transverse correction in late adolescents and young adults with optimum orthopedic effects. However, the success rate of MARPE shows a negative correlation with age. Although MARPE offers an effective method for correcting a transverse skeletal deficiency, given the appliance cost and increased risk for complications, it could present challenges for adult patients and practitioners in daily practice.

AIMS

In this article, current advances in maxillary skeletal expansion are summarized, and a new MARPE concept is introduced.

CONCLUSION

The new MARPE design offers several advantages to other existing methods: (1) it can be installed directly to the patient in the clinical setting with no additional laboratory waiting times. (2) It is purely a bone-borne appliance. (3) The appliance is designed to be placed in the thickest part of the anterior palate to maximize the cortical and trabecular bone support. (4) Allows for bicortical placement of the miniscrews with no perforations in the nasal floor. Finally, (5) offers an esthetic and minimalistic approach to maxillary skeletal expansion in late adolescent and adult patients.

A novel biomechanical system to intrude the upper incisors and control overbite: Posterior miniscrew-assisted lever arm and 2 cases report

RATIONALE

Overbite control is a key factor in orthodontic treatment. In some cases, incisor intrusion is essential and could be an optimal strategy for overbite control. The aim of this article was to introduce a biomechanical system called the posterior miniscrew-assisted lever arm, which is innovative in using existing posterior miniscrews to intrude the upper incisors and to control anterior overbite while simultaneously retracting the anterior teeth. Its efficiency in incisor intrusion has been proved with 2 cases.

PATIENT CONCERNS

Two adult women who came for orthodontic treatment with the chief complaint of convex profile were included in this study.

DIAGNOSIS

Both patients had similar malocclusions of Class II molar relationship, anterior deep overjet, and anterior deep overbite.

INTERVENTIONS

Their treatment plans were to extract 4 first premolars and insert 2 maxillary posterior buccal miniscrews. After teeth aligning and leveling, en masse retraction was started in both arches. During the space-closing stage, posterior miniscrew-assisted lever arms were placed in their upper arches so as to intrude upper incisors and control the overbite.

OUTCOMES

After respectively 4 months and 3 months of incisor intrusion, the anterior overbite was successfully reduced to the normal range in each patient. Cephalometric analysis and superimposition also confirmed the treatment effect of this biomechanical system on incisor intrusion.

LESSONS

The posterior miniscrew-assisted lever arm is a valuable biomechanical system for intruding incisors and controlling anterior overbite.

Smart distalization of the upper arch with an easy, efficient and no-compliance procedure

In conventional Class II treatment, distalisation of the maxillary arch usually requires multiple phases of tooth movement during which anchorage loss can occur. In order to solve this issue, a rational and simple technique has been developed. Instead of using intraoral distalisers along with palatal mini-implants, Ni-Ti superelastic loops are used to obtain molar distalisation while buccal interradicular miniscrews (BIM), preferably placed between the roots of upper premolars, supply the necessary anchorage. Once the distalisation of molars and second premolars is performed, miniscrews are placed between the roots of first molars and second premolars after removing the previous miniscrews. Elastic chains or tie-backs, which go from the new miniscrews to the hooks of a 0.019×0.025-inch stainless-steel archwire, produce the retraction of incisors, canines and first premolars with optimal control of anchorage. Clinical cases are shown to illustrate the technique.

Evaluation and Comparison of the Effect of Elastomeric Chain and Stainless Steel Ligature Wire on Maxillary Orthodontic Miniscrew Failure

Context:

Orthodontic miniscrews are used for the purpose of conservation of anchorage.

Aims:

The aim of the study was to evaluate the orthodontic miniscrew failure between the elastomeric chain-supported retraction and stainless steel (SS) ligature-aided retraction.

Settings and Design:

This was a cross-sectional split mouth randomized controlled trial.

Materials and Methods:

The sample (30) was divided equally among the control group and the experimental group (15 each). Miniscrews were placed between second premolar and the first molar of maxilla. The experimental group was based on the split mouth technique wherein right or left side of the maxillary arch was treated using either an elastomeric power chain (EPC) engaged to the miniscrews directly (Group 1) or an EPC engaged indirectly to miniscrews with the help of SS ligature wire (Group 2). In control group, implants were placed in maxilla without any retraction force. Clinical signs of inflammation was assessed at the following interval; 7^th day, 14^th day, 1^st month, 2^nd month, and at the time of removal of implant.

Statistical Analysis Used:

Kruskal–Wallis ANOVA test was used.

Results:

Mean rank of gingival inflammation was 28.33 at the 1^st-month interval in Group 1 and inflammation remained high in the this group for all time intervals in comparison to Group 2. Group 2 showed highest mean rank of inflammation of 26.10 at 7^th day. In control group, the inflammation remained low at all the time intervals. Moreover, the difference noted was statistically significant.

Conclusions:

The gingival inflammation around the peri-implant tissue with the application of EPC at various interval remained high in comparison to the EPC with SS group. The gingival inflammation in the control group was very less, and it remained less throughout the different time periods.

Effects of Intrabony Length and Cortical Bone Density on the Primary Stability of Orthodontic Miniscrews

Miniscrews have gained recent popularity as temporary anchorage devices in orthodontic treatments, where failure due to sinus perforations or damage to the neighboring roots have increased. Issues regarding miniscrews in insufficient interradicular space must also be resolved. This study aimed to evaluate the primary stability of miniscrews shorter than 6 mm and their feasibility in artificial bone with densities of 30, 40, and 50 pounds per cubic foot (pcf). The primary stability was evaluated by adjusting the intrabony miniscrew length, based on several physical properties: maximum insertion torque (MIT), maximum removal torque (MRT), removal angular momentum (RAM), horizontal resistance, and micromotion. The MIT and micromotion results demonstrated that the intrabony length of a miniscrew significantly affected its stability in low-density cortical bone, unlike cases with a higher cortical bone density (p < 0.05). The horizontal resistance, MRT, and RAM were affected by the intrabony length, regardless of the bone density (p < 0.05). Thus, the primary stability of miniscrews was affected by both the cortical bone density and intrabony length. The effect of the intrabony length was more significant in low-density cortical bone, where the implantation depth increased as more energy was required to remove the miniscrew. This facilitated higher resistance and a lower risk of falling out.

Mechanical Evaluation of the Stability of One or Two Miniscrews under Loading on Synthetic Bone

The aim of the present study was to evaluate the primary stability of a two-miniscrew system inserted into a synthetic bone and to compare the system with the traditional one. Forty-five bi-layered polyurethane blocks were used to simulate maxillary cancellous and cortical bone densities. Samples were randomly assigned to three groups—one-miniscrew system (Group A, N = 23), two-miniscrew system (Group B, N = 22) and archwire-only (Group C, N = 10). A total of 67 new miniscrews were subdivided into Group A (23 singles) and Group B (22 couples). 30 mm of 19″ × 25″ archwires were tied to the miniscrew. The load was applied perpendicularly to the archwire. Maximum Load Value (MLV), Yield Load (YL) and Loosening Load (LL) were recorded for each group. The YL of Group B and C had a mean value respectively of 4.189 ± 0.390 N and 3.652 ± 0.064 N. The MLV of Group A, B and C had a mean value respectively of 1.871 ± 0.318N, of 4.843 ± 0.515 N and 4.150 ± 0.086 N. The LL of Group A and B had a mean value respectively of 1.871 ± 0.318 N and of 2.294 ± 0.333 N. A two- temporary anchorage device (TAD) system is on average stiffer than a one-TAD system under orthodontic loading.

Influence of bone density, screw size and surgical procedure on orthodontic mini-implant placement - part B: implant stability

This in vitro study aimed to investigate the influence of bone density, implant size, and surgical procedure on the primary stability (PS) of orthodontic mini-implants (OMIs). In total, 640 OMIs of various sizes (2.0 × 7, 2.3 × 7, 2.0 × 11 and 2.3 × 11 mm) were inserted in the artificial bone of different densities (D1-D4). Placement was performed with an insertion angle of 90° or 60° to the bone surface and in 320 cases without predrilling, which resulted in 64 groups. PS was measured on the basis of implant stability quotient (ISQ) and insertion torque (IT). With regard to all possible influencing parameters, the mean PS differed between 39.20 and 60.00 (ISQ), and 10.00 and 39.00 Ncm (IT). The effect of OMI size and surgical procedure was dependent on bone quality. For example, implant size had less effect in high-density bone and was stronger with decreasing density. Overall, implant length had a greater influence than the diameter, and a high correlation was found among both PS measurement techniques. Therefore, a suitable choice of implant size and surgical protocol with regard to bone density can positively influence PS. In principle, ISQ and IT are suitable for measuring OMI stability.

Influence of bone density, screw size and surgical procedure on orthodontic mini-implant placement - part A: temperature development

The aim of this in vitro study was to determine the influence of bone density, orthodontic mini-implant (OMI) size, and the surgical procedure on temperature increase during implant site osteotomy and placement. OMIs of different sizes (2.0×7, 2.3×7, 2.0×11, and 2.3×11mm) were placed in artificial bone blocks of different densities (D1-D4). Optionally, the drilling and insertion angle was 90° or 60° to the bone surface. A total of 640 OMIs were inserted, and predrilling was performed in 320 cases. All insertions were done without irrigation with an axial load of 20N, which resulted in 64 groups. Temperature measurements were performed during implant site preparation and placement using Type-K-thermocouples. Mean temperature increase differed for OMI osteotomy between 1.38°C and 8.75°C and placement between 3.8°C and 18.74°C, respectively. Critical thermal increase was especially reached during placement using long implants. Increasing bone density and implant size (diameter <length) correlated with thermal increase. Predrilling and angulated implant placement resulted in less heat development. Critical temperature behaviour in high-density bone could be partially responsible for the high failure rates of OMI placement in the lower jaw. The influence of the implant size on temperature development should be considered when selecting an OMI.

Biological Effects of Anodic Oxidation on Titanium Miniscrews: An In Vitro Study on Human Cells

This controlled in vitro study compared the effects of varying the thickness of a TiO₂ layer on cellular activity using commercially available miniscrew samples with identical surface features to derive information with direct clinical impact. Titanium grade V plates with four different thicknesses of TiO₂ layer/color were used: absent/gray (Control group), 40–50 nm/pink (Pink group), 130 nm/gold (Gold group) and 140 nm/rosé (Rosé group). In vitro experiments used Saos-2 cells and included cell growth analysis, phospho-Histone H3 and procollagen I staining, cell viability analysis, and a cell migration assay at 12, 24, 40 and to 48 h. Few differences were seen among the groups, with no clear behavior of cellular activity according to the TiO₂ thickness. The Control group showed a greater cell count. Phospho-Histone H3 staining was similar among the groups and procollagen I staining was greater in the Rosé group. Cell viability analysis showed a significant difference for live cell counts (greater in the Rosé group) and no difference for the dead cell counts. The cell migration assay showed a delay for the Rosé group up to 40 h, where full repopulation of cell-free areas was obtained at 48 h. The results suggest that the TiO₂ layers of the commercial miniscrews have minimal biological effects, including cytotoxicity, with possibly negligible or minimal clinical implications.

Effect of Bracket Slot and Archwire Dimension on Posterior Tooth Movement in Sliding Mechanics: A Three-dimensional Finite Element Analysis

Introduction

Space closure by molar protraction has always been a challenge in orthodontic treatment due to larger root surface area which requires additional anchorage. Ideally, there should be little or no tipping. However, the protraction forces, being occlusal and buccal to the centre of resistance (CR) of the tooth, cause tipping and rotations.

Aim

The aim of the study was to assess the effect of bracket slot and archwire dimensions on posterior tooth movement during space closure in sliding mechanics and evaluate the length of power arm to bring about translatory movement of teeth using three-dimensional finite element analysis.

Materials and methods

A model of the maxillary teeth was created and converted to a finite element format through a meshing software, Hypermesh. Two three-dimensional models, each with a combination of 0.017”× 0.022” archwire in 0.018” slot (model 1) and 0.019”×0.025” archwire in 0.022” slot (model 2), were generated. Power arms of different lengths were attached to the first molar. Miniscrew was inserted between the canine and first premolar.

Results

In model one, the power arm of 10-mm height provided controlled tooth movement than the one with 6 mm height, and in model two, power arms of both 6-mm and 10-mm height produced controlled tooth movement.

Conclusions

As the force was raised apically from the slot, more translation was observed. Power arm of 6-mm height can be used due to anatomic limitation of the vestibule.

Is It Possible to Protract the Maxilla by Surgically Assisted Rapid Maxillary Expansion and Intermaxillary Class III Elastics?

Objective

The purpose of the present study was to evaluate skeletal and soft tissue changes with surgically assisted rapid maxillary expansion (SARME) and intermaxillary Class III elastics.

Methods

A total of 15 patients (mean age: 19.58 years) were included in the study. Each patient underwent SARME with the use of Class III elastics (500 g) applied through miniscrews to stimulate maxillary advancement. Lateral cephalograms and posteroanterior radiographs obtained before treatment (T1), after SARME and elastic use (T2), and after treatment (T3) were analyzed to determine the changes in each phase of treatment. Planimeter was used to evaluate facial soft tissue changes. Wilcoxon signed-rank test was used to evaluate the changes that occur during treatment.

Results

SARME provided permanent and efficient maxillary expansion at both skeletal and dental levels (p<0.01). Maxillary skeletal (ANS-Ver and U1i-Ver; p<0.01) and soft tissue (Pr-Ver, Sn-Ver, and ULA-Ver; p<0.01) variables and superior upper labial area (Area 1; p<0.05) increased due to maxillary dental and skeletal changes. Superior lower labial area (Area 3; p<0.05) decreased as a result of slight increase in facial height and changes in maxillary-mandibular incisor relationship at the end of the treatment.

Conclusion

The results suggest that the improvement in the facial profiles of the patients is related to the significant increase in the bony and dental support of the upper lip region together with the contribution of the superior lower lip area.

Anchorage effectiveness of orthodontic miniscrews compared to headgear and transpalatal arches: a systematic review and meta-analysis

BACKGROUND

Anchorage in orthodontics can be provided through several extra- and intra-oral sources including headgear, teeth, cortical bone and soft tissue.

OBJECTIVE

The aim of this review was to systematically review the effectiveness of miniscrews in reinforcing anchorage during en-masse retraction of anterior teeth in comparison to conventional anchorage appliances. Search method: Comprehensive searching of the electronic databases was undertaken up to March 2018 in the Cochrane Database of Systematic review, Cochrane Central Register of Controlled Trials, MEDLINE via PubMed and Scopus databases. Additional searching for on-going and unpublished data and hand search of relevant journals were also undertaken, authors were contacted, and reference lists screened. Eligibility criteria: Searches were restricted to randomized clinical trials (RCTs) published in English, which compared anchorage reinforcement using mechanically-retained miniscrews (diameter of 2 mm or less) to conventional anchorage appliances during en-masse retraction of anterior teeth in participants of any age treated with fixed appliances combined with extraction of maxillary premolars.

DATA COLLECTION AND ANALYSIS

Blind and induplicate study selection, data extraction and risk of bias assessment were undertaken. The primary outcome was the amount of mesial movement of the upper first permanent molar (anchorage loss) while secondary outcomes included treatment duration, number of visits, adverse effects and patient-centered outcomes. The risk of bias was assessed using Cochrane risk of bias tool. A random-effects model with its corresponding 95% confidence interval (CI) were generated for comparable outcomes. Statistical heterogeneity across the studies were assessed using the I² and Chi² test. Additional sensitivity tests were implemented.

RESULTS

Seven RCTs met the inclusion criteria, however, data of 241 participants from 6 RCTs (250 miniscrews and 134 conventional anchorage appliances) were meta-analyzed. Qualities of the included RCTs varied from low to high. The standardized mean difference (SMD) of the anchrage loss between the two intervention groups was 2.07 mm ((95% CI (-3.05) to (-1.08), p < .001, I² = 88%, 6 RCTs)) in favour of miniscrews, which was also preserved after excluding the high risk of bias studies (SMD 1.94 mm, 95% CI (-2.46) to (-0.42) p < .001, I² = 93%, 3 RCTs)). Information on overall treatment duration, space closure duration, quality of treatment, patient-reported outcomes, adverse effects and number of visit were limited.

CONCLUSION

The result of the meta-analysis suggested that there is moderate quality of evidence that miniscrews are clinically and statistically more effective in preserving orthodontic anchorage than conventional appliances. However, this conclusion is supported by a small number of studies with variable qualities. High-quality RCTs would give a better understanding of miniscrews effectiveness in providing orthodontic anchorage.

Nonsurgical treatment and stability of an adult with a severe anterior open-bite malocclusion

OBJECTIVES

A skeletal anterior open-bite is a challenging malocclusion for the orthodontist due to the difficulty and instability of correction. Treatment options for the adult patient include extractions, anterior extrusion with intermaxillary elastics, posterior intrusion using skeletal anchorage, occlusal adjustment, and orthognathic surgery. Patient compliance plays a key role in posttreatment stability. The present case report demonstrates the orthodontic treatment of an adult patient who presented with a complex open-bite malocclusion.

MATERIALS AND METHODS

Treatment involved the placement of four miniscrews to assist intrusion of maxillary molars by applying posterior vertical maxillary elastics and extrusion of the anterior segments using anterior vertical interarch elastics.

RESULTS

Ideal intercuspation was successfully achieved and good stability was maintained during 3 years following treatment.

CONCLUSION

The intrusion of the maxillary molars with miniscrews is an interesting option in selected cases of skeletal anterior open bite. The retention protocol should be specific in these cases.

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.

Facet joint disturbance induced by miniscrews in plated cervical laminoplasty: Dose it influence the clinical and radiologic outcomes?

A retrospective cohort study. Plated cervical laminoplasty is an increasingly common technique. A unique facet joint disturbance induced by lateral mass miniscrews penetrating articular surface was noticed. Facet joints are important to maintain cervical spine stability and kinetic balance. Whether this facet joint disturbance could affect clinical and radiologic results is still unknown. The objective of this study is to investigate the clinical and radiologic outcomes of patients with facet joints disturbance induced by miniscrews in plated cervical laminoplasty.A total of 105 patients who underwent cervical laminoplasty with miniplate fixation between May 2010 and February 2014 were comprised. Postoperative CT images were used to identify whether facet joints destroyed by miniscrews. According to facet joints destroyed number, all the patients were divided into: group A (none facet joint destroyed), group B (1-2 facet joints destroyed), and group C (≥3 facet joints destroyed). Clinical data (JOA, VAS, and NDI scores), radiologic data (anteroposterior diameter and Palov ratio), and complications (axial symptoms and C5 palsy) were evaluated and compared among the groups.There were 38, 40, and 27 patients in group A, B, and C, respectively. The overall facet joints destroyed rate was 30.7%. All groups gained significant JOA and NDI scores improvement postoperatively. The preoperative JOA, VAS, NDI scores, and postoperative JOA scores did not differ significantly among the groups. The group C recorded significant higher postoperative VAS scores than group A (P = 0.002) and B (P = 0.014) and had significant higher postoperative NDI scores than group A (P = 0.002). The pre- and postoperative radiologic data were not significant different among the groups. The group C had a significant higher axial symptoms incidence than group A (12/27 vs 8/38, P = 0.041).Facet joints disturbance caused by miniscrews in plated cervical laminoplasty may not influence neurological recovery and spinal canal expansion, but may negatively affect postoperative axial symptoms.

Effectiveness of methods for detaching orthodontic implants likely to fracture upon rotational torque - an animal study

Orthodontic implants may fracture at the cortical bone level upon rotational torque. The impacted fragment can be detached by a range of methods, which are all more or less time-consuming and injurious to the cortical bone. The aim of this study was to compare three different methods for detaching an orthodontic implant impacted in cortical bone. Health Sciences University of Hokkaido animal ethics committee approved the study protocol. Orthodontic titanium-alloy (Ti-6Al-4 V) implants were placed bilaterally on the buccal side of the mandible of beagle dogs. Subsequently, the implants were detached using either a low-speed handpiece with a round bur, alternatively by use of a low-power or a high-power ultrasonic instrument. In the first experiment, 56 orthodontic implants were placed into the dissected mandible from 7 animals. The methods for detachment were compared with respect to time interval, as well as associated undesirable bone loss as appraised by use of cone-beam computed tomography. In experiment two, 2x2 implants were placed bilaterally in the mandible of 8 animals and subsequently detached by manual rotational torque, and the described three methods for detachment. The implant socket was investigated histologically as a function of removal method immediately after removal, and after 1, 3 and 8 weeks and contrasted with the healing of the socket of the implant that was detached by manual rotational torque. Statistical significance was appraised by the use of non-parametric Kruskal-Wallis one-way analysis of variance. The method using the low-power ultrasonic required significantly longer removal time versus the two other methods, i.e. high-power ultrasonic and low-speed handpiece with a round bur (p < 0.02). The amount of undesirable bone loss was substantially larger with low-speed handpiece with a round bur compared to the two ultrasonic methods (p < 0.05). Bone formation after 3 weeks of healing was more complete following the use of low or high-power ultrasonic instrument in comparison with a low-speed handpiece rotary instrument method. Orthodontic implants likely to fracture upon rotational torque or impacted fractured fragments should be detached preferably with an ultrasonic instrument, because of less associated bone loss and more rapid bone healing compared to the use of a low-speed handpiece rotary instrument.

Current trends in miniscrew utilization among Indian orthodontists

Background:

There is limited data about current utilization of miniscrews in orthodontic practices in India. The purpose of this survey was to obtain information on clinical utilization of miniscrews among orthodontists in India.

Materials and Methods:

A survey questionnaire was prepared and mailed to 2100 qualified and registered orthodontists in India.

Results:

A total of 1691 orthodontists responded to the survey, with a response rate of 80.52%. Among them, 952 (56.3%) had never used miniscrews in their clinical practice. Seven hundred and thirty-nine (739) (43.7%) had utilized miniscrews in their treatment, at some point of time. Among the orthodontists who used miniscrews, 463 (62.65%) used a surgical guide for positioning the miniscrews and 276 (37.35%) placed miniscrews without a surgical guide. Six hundred and thirty-four (634) (85.79%) orthodontists placed the miniscrews personally while 105 (14.21%) utilized the help of other specialists for placing the miniscrews. Among the orthodontists who used miniscrews, 76 (10.28%) utilized the help of oral surgeon to place the miniscrews while 29 (3.93%) utilized the help of periodontists to do the procedure.

Conclusion:

Miniscrews are a useful addition to the orthodontic armamentarium. The major indication for miniscrew was indirect anchorage in critical anchorage cases. The most important factors in determining the clinical utilization of miniscrews as a part of the treatment modality depends upon operator training and skill; fear of complications, patient refusal to accept miniscrews and the clinician's preference for conventional methods without unnecessary invasive procedure.

Comparison between Herbst appliances with or without miniscrew anchorage

Background:

Herbst appliance is largely used in orthodontics for the correction of Class II. The aim of this paper was to analyze dental and skeletal effects of a splints Herbst-miniscrews combined device in comparison to a mandibular splints Herbst appliance.

Materials and Methods:

Fifty Class II division 1 patients (27 males and 23 females with a mean age of 11.8 ± 1.7 years) were included in the study. Lateral headfilms of 25 patients with a mandibular resin splint and a miniscrew anchorage (test group) and of 25 patients with mandibular acrylic resin splints (control group) were analyzed before (T0) and after (T1) the Herbst treatment. The mean and standard deviation (SD) of each variable were calculated; paired t-test was used to evaluate statistical changes before and after the treatment, in each group and Student t-test was used to compare the two groups.

Results:

Significant differences were observed for P < 0.05. At the end of the Herbst treatment, mandibular incisor proclination was significantly lower in the test group (2.8°) in comparison to the control group (7.4°).

Conclusions:

The miniscrew-Herbst system, described in the present study, allows correction of Class II malocclusion, with a lower anchorage loss, in form of mandibular incisor proclination, during the treatment, in comparison to mandibular acrylic splints Herbst.

Comparison of two implant-supported molar distalization systems

OBJECTIVE

To examine skeletal, dental, and soft tissue effects of the Miniscrew Implant Supported Distalization System (MISDS) and the Bone-Anchored Pendulum Appliance (BAPA).

MATERIALS AND METHODS

Among 28 patients displaying Angle Class II malocclusion, 14 patients with a mean age of 14.8 ± 3.6 years treated with MISDS were included in the first group, and 14 patients with a mean age of 14.5 ± 1.5 years treated with BAPA were included in the second group. The pretreatment and posttreatment lateral cephalograms were analyzed. Statistical evaluation was carried out using the paired Shapiro-Wilk test, the paired-sample t-test, and the unpaired t-test.

RESULTS

Upper posterior teeth were distalized successfully in both groups. Nearly bodily distalization was seen in the MISDS group, whereas significant distal tipping of the upper first molars was observed in the BAPA group (P < .001). There were no statistically significant changes in the sagittal position of the maxilla and mandible and in the position of the upper incisors as a result of treatment in either group.

CONCLUSIONS

Both methods provided absolute anchorage for distalization of posterior teeth; however, almost translatory distal movement was encountered in the MISDS group, and substantial distal tipping of the maxillary molars accompanied distalization in the BAPA group.