Accuracy of direct insertion of TADs in the anterior palate with respect to a 3D-assisted digital insertion virtual planning

Is simultaneous placement of orthodontic mini-implants and skeletally anchored appliances advisable? : CBCT-based cadaver study comparing the accuracy of the digital workflow with methods requiring two visits

PURPOSE

For the fabrication of an orthodontic mini-implant (OMI)-borne appliance, the position of the inserted OMI can be detected by a silicone impression or an intraoral scan (IOS). In case of digital planning, it can be taken over from the planning and the appliance can be produced in advance. This study aimed to evaluate the accuracy of these three techniques and whether there is an association with the insertion angle.

METHODS

Two OMIs were digitally planned and placed in the anterior palate of 11 human cadavers with different insertion angles. Subsequently, the position of each OMI was detected by an IOS, a silicone impression, and a cone-beam computed tomography (CBCT) scan, whereby the CBCT scan was set as "real position". The measurements of accuracy were performed between the CBCT data as a reference and the preoperative digital planning, the IOS and the plaster model manufactured from the silicone impression.

RESULTS

The IOS was the most accurate in detecting the Top (mean deviation 0.14 mm) and the Apex (mean deviation 0.36 mm) of the OMIs. Significant linear deviations between the three modalities were registered for both Top (p < 0.001) and Apex (p = 0.010). The digital planning procedure achieved the lowest mean angular deviation of 3.7° and was significantly more accurate in this respect than the IOS (p < 0.001).

CONCLUSION

All methods were subject to small, but clinically irrelevant deviations. Within the limitations of a cadaver study, all methods appear to be suitable for clinical use. However, the digital workflow could be advantageous, requiring only a single visit for OMI placement and simultaneous appliance fitting.

Automatic Segmentation of the Jaws Used in Guided Insertion of Orthodontic Mini Implants to Improve Their Stability and Precision

Background and Objectives: With the goal of identifying regions with bicortical bone and avoiding root contact, the present study proposes an innovative technique for the simulation of the insertion of mini orthodontic implants using automatic jaw segmentation. The simulation of mini implants takes place in 3D rendering visualization instead of Multi-Planar Reconstruction (MPR) sections. Materials and Methods: The procedure involves utilizing software that automatically segments the jaw, teeth, and implants, ensuring their visibility in 3D rendering images. These segmented files are utilized as study models to determine the optimum location for simulating orthodontic implants, in particular locations characterized by limited distances between the implant and the roots, as well as locations where the bicortical structures are present. Results: By using this method, we were able to simulate the insertion of mini implants in the maxilla by applying two cumulative requirements: the implant tip needs to be positioned in a bicortical area, and it needs to be situated more than 0.6 mm away from the neighboring teeth's roots along all of their axes. Additionally, it is possible to replicate the positioning of the mini implant in order to distalize the molars in the mandible while avoiding the mandibular canal and the path of molar migration. Conclusions: The utilization of automated segmentation and visualization techniques in 3D rendering enhances safety measures during the simulation and insertion of orthodontic mini implants, increasing the insertion precision and providing an advantage in the identification of bicortical structures, increasing their stability.

Transfer accuracy of 3D printed versus CAD/CAM milled surgical guides for temporary orthodontic implants: A preclinical micro CT study

OBJECTIVES

Temporary anchorage devices (TADs) have become an integral part of comprehensive orthodontic treatments. This study evaluated the transfer accuracy of three-dimensional (3D) printed and computer-aided design/computer-aided manufacturing (CAD/CAM) milled surgical guides for orthodontic TADs using micro-computed tomography (CT) imaging in a preclinical trial.

METHODS

Overall, 30 surgical guides were used to place TADs into typodonts; 3D printing and CAD/CAM milling were used to produce the guides. The virtual target positions of the TADs were compared to the real positions in terms of spatial and angular deviations using digital superimposition. Micro-CT imaging was used to detect the positions. To evaluate reliability, two investigators collected the measurements twice. Intra-rater and inter-rater correlations were tested.

RESULTS

In total, 60 palatal TADs were evaluated. The mean coronal deviations in the print group ranged from 0.15 ± 0.20 mm to 0.71 ± 0.22 mm, whereas in the mill group, they ranged from 0.09 ± 0.15 mm to 0.83 ± 0.23 mm. At the apical tip, the overall deviations in the print group ranged from 0.14 ± 0.56 mm to 1.27 ± 0.66 mm, whereas in the mill group, they ranged from 0.15 ± 0.57 mm to 1.09 ± 0.44 mm. The mean intra-class and inter-class correlation coefficients ranged from 0.904 to 0.987. No statistically significant differences were found between the groups.

CONCLUSIONS

CAD/CAM milled guides yielded spatial and angular accuracies comparable to those of 3D printed guides with notable deviations in the vertical positioning of TADs.

CLINICAL SIGNIFICANCE

Digital planning of orthodontic temporary implants combines clinical predictability and the safety of surrounding tissue. Therefore, the transfer accuracy of the guides is crucial. This preclinical study was the first to evaluate CAD/CAM milling for orthodontic guides and found its accuracy comparable to that of the current "gold standard".

Accuracy of Palatal Orthodontic Mini-Implants Placed Using Fully Digital Planned Insertion Guides: A Cadaver Study

Digital workflows have become integral in orthodontic diagnosis and therapy, reducing risk factors and chair time with one-visit protocols. This study assessed the transfer accuracy of fully digital planned insertion guides for orthodontic mini-implants (OMIs) compared with freehanded insertion. Cone-beam computed tomography (CBCT) datasets and intraoral surface scans of 32 cadaver maxillae were used to place 64 miniscrews in the anterior palate. Three groups were formed, two using printed insertion guides (A and B) and one with freehand insertion (C). Group A used commercially available customized surgical templates and Group B in-house planned and fabricated insertion guides. Postoperative CBCT datasets were superimposed with the planning model, and accuracy measurements were performed using orthodontic software. Statistical differences were found for transverse angular deviations (4.81° in A vs. 12.66° in B and 5.02° in C, p = 0.003) and sagittal angular deviations (2.26° in A vs. 2.20° in B and 5.34° in C, p = 0.007). However, accurate insertion depth was not achieved in either guide group; Group A insertion was too shallow (-0.17 mm), whereas Group B insertion was deeper (+0.65 mm) than planned. Outsourcing the planning and fabrication of computer-aided design and computer-aided manufacturing insertion guides may be beneficial for certain indications; particularly, in this study, commercial templates demonstrated superior accuracy than our in-house-fabricated insertion guides.

Accuracy of digital workflow for placing orthodontic miniscrews using generic and licensed open systems. A 3d imaging analysis of non-native .stl files for guided protocols

BACKGROUND

This study aimed to assess the accuracy of digital workflow for guided insertion of miniscrews in the anterior palate using restorative implant dentistry software and licensed software for orthodontic applications.

METHODS

Twenty subjects (8 males, 12 females, mean age = 16.7 ± 2.1 years) were prospectively selected to receive guided insertion of bicortical palatal miniscrews. Virtual planning was performed using restorative implant dentistry software (Blue Sky Plan*, version 4.7) (group 1 = 10 subjects) and licensed orthodontic software (Dolphin Imaging Software, version 11.0) (group 2 = 10 subjects). A specific 3D Imaging technology was applied to permit the registration of the planned and achieved position of the miniscrews based on the superimposition of maxillary models. The angular deviation (accuracy error) between the planned and the achieved positions of the miniscrews were recorded. Independent Student's test was used with statistical significance set at p value < 0.05.

RESULTS

The mean accuracy error recorded in group 1 was 7.15° ± 1.09 (right side) and 6.19 ± 0.80 (left side) while the mean error in group 2 was 6.74° ± 1.23 (right side) and 5.79 ± 0.95 (left side). No significant differences were recorded between the two groups (p > 0.05); instead, miniscrews placed on the right side were almost one degree higher than the left side (p < 0.05) in both groups.

CONCLUSIONS

The clinical accuracy error was similar when using generic and licensed orthodontic software for guided systems.

Systematic review and network meta-analysis of the accuracy of the orthodontic mini-implants placed in the inter-radicular space by image-guided-based techniques

OBJECTIVE

The aim of the present systematic review and network meta-analysis (NMA) is to analyze the accuracy of image-guided-based orthodontic mini-implants placement techniques in the inter-radicular space.

METHODS

The study was conducted under the PRISMA recommendations. Three databases were searched up to July 2022. In vitro randomized experimental trials (RETs) including static computer-aided implant surgery (s-CAIS), mixed reality (MR), soft tissue static computer-aided implant surgery (ST s-CAIS) and conventional free-hand technique (FHT) for the orthodontic mini-implants placement in the inter-radicular space were selected. The risk of bias was assessed using the Current Research Information System scale. A random effects model was used in the NMA. Direct comparisons were combined with a random effects model in a frequentist NMA to estimate indirect comparisons, and the estimated effect size of the comparisons between techniques were analyzed by difference of means. Inconsistency was assessed with the Q test, with a significance level of p < 0.05, and a net heat plot.

RESULTS

A total of 92 articles was identified, and 8 RETs (8 direct comparisons of 4 techniques) were included in the NMA, which examined 4 orthodontic mini-implants placement techniques: s-CAIS, MR, ST s-CAIS, and FHT. Taking FHT as reference, s-CAIS and ST s-CAIS showed statistically significant coronal and apical deviation. In addition, s-CAIS showed statistically significant angular deviation. However, MR did not show statistically significant differences with respect to FHT, which presented the highest p-score. At the coronal deviation, ST s-CAIS presented the highest P-score (0.862), followed by s-CAIS (0.721). At the apical deviation, s-CAIS presented the highest P-score (0.844), followed by ST s-CAIS (0.791). Finally, at the angular deviation s-CAIS presented again the highest P-score (0.851).

CONCLUSIONS

Within the limitations of this study, it was found that the image-guided-based orthodontic mini-implants placement techniques showed more accuracy than the free-hand conventional placement technique; specially the computer-aided static navigation techniques for the orthodontic mini-implants placed in the inter-radicular space.

Comparison of the Accuracy of Two Transfer Caps in Positional Transmission of Palatal Temporary Anchorage Devices: An In Vitro Study

The aim of this study was to compare the positional information transfer accuracy of palatal temporary anchorage devices (TADs) of two different brands of transfer caps: PSM and Leone. Thirty plaster casts of maxillary dental arches were chosen for master models. A couple of Leone TADs were inserted in each master model. For each master model, two analysis models were created: using two transfer caps, Leone and PSM, the impressions were taken, the analogues were connected on the transfer caps, and the casts were poured. Using digital methods and equipment, such as a 3D scanner, a 3D analysis and a comparison of the accuracy of the two transfer caps in transferring the positional information of the TADs was then made. The data obtained were analyzed using the Mann-Whitney U-test at a significance level of α = 0.05. PSM transfer caps showed higher error frequency in almost all measurements. Only two measurements had a larger error in the analysis models made with Leone transfer caps. The Mann-Whitney U-test found a significant difference between the error levels of TADs found in the analysis models created with PSM transfer caps. Leone transfer caps showed greater reliability in TADs positional information transmission.

FEM Analysis of Individualized Polymeric 3D Printed Guide for Orthodontic Mini-Implant Insertion as Temporary Crown Support in the Anterior Maxillary Area

Either due to trauma, extraction or congenital factors, the absence of teeth has aesthetic, functional, financial and psychological consequences. The aim of the current study is to assess an individualized polymeric 3D printed digitally planned surgical guide designed to achieve precision and predictability in non-standard mini-implant orthodontic cases. Twenty-seven patient records with missing anterior teeth were selected from the database of a private clinic in Timisoara, Romania. Based on the analysis of the cases included in the research, a surgical guide for the insertion of mini-implants as provisional crown support was designed. An FEM simulation was performed using the Abaqus numerical analysis software. Finite element simulation revealed the maximum displacements and stresses that occur in the surgical guide. Mini-implant supported provisional crowns can be a simple and low-cost method to increase patient self-esteem and compliance with the orthodontic treatment. Computer aided mechanical simulation is a useful tool in analyzing different polymeric surgical guide designs before being used in clinical situations in order to avoid failure.

Laser Surgical Approach of Upper Labial Frenulum: A Systematic Review

An abnormal and hypertrophied upper labial frenulum (ULF) can cause diastemas, gingival recession, eruption abnormalities, and the onset of carious and periodontal problems in the upper central incisors, as well as aesthetic and functional disorders of the upper lip. The goal of this investigation is to review the evidence on the surgical techniques that are currently available for treating ULF in order to identify the best approach. PubMed, Scopus, Cochrane Library, and Embase were searched for papers that matched our topic from 13 November 2012 up to 22 November 2022 using the following Boolean keywords: "frenulum" and "surgery*". A total of eight articles were selected for the purpose of the review. ULF can be surgically treated using either traditional scalpel surgery or laser surgery. The latter is the better option due to its intra- and post-operative benefits for both the patients and the clinicians, in terms of faster healing, fewer side effects and discomfort, and greater patient compliance. However, a higher learning curve is required for this technique, especially to calibrate the appropriate power of the laser. To date, it is not possible to identify which type of laser achieves the best clinical results for the treatment of ULF.

Accuracy of palatal orthodontic mini-implants placed by conventionally or CAD/CAM-based surgical guides: a comparative in vitro study

OBJECTIVES

To investigate and compare the transfer accuracy of five different surgical guides (SGs) for the insertion of orthodontic mini-implants (OMIs) in the anterior palate.

MATERIALS AND METHODS

Stereolithographic files of 10 maxillary patient models and their corresponding lateral cephalograms were virtually matched and used for planning the position of two parallel OMIs in the paramedian region of the anterior palate. For each patient model, three 3-dimensional (3D)-printed and two conventional SGs were manufactured from different materials, and a total of 96 OMIs were transferred to the anterior palates of the respective 50 molded resin models. The planned (T0) and the actual (T1) OMI positions were analyzed and compared after superimposition of the digitized models. The deviations between the OMI positions in T0 and T1 were described as the distance between the head and the tip, respectively, of each OMI in millimeters and the deviating angle between the OMI axes for each patient and SG.

RESULTS

The conventionally manufactured SGs of Pattern Resin LS (GC Europe N.V., Leuven, Belgium) showed the highest linear and angular transfer accuracy for the insertion of OMIs. The highest deviations were found with the SGs made of IMPRIMO LC Splint (3D-printed; Scheu-Dental, Iserlohn, Germany) and Memosil 2 (conventional SG; Kulzer, Hanau, Germany).

CONCLUSIONS

The 3D-printed SGs did not reach the accuracy of the conventional SGs made of Pattern Resin but may provide sufficient accuracy for palatal OMI placement.

Does the planned minsicrew position reflect the achieved one? A clinical study on the reliability of guided minsicrew insertion using lateral cephalogram and maxillary stereolithography file for planning

INTRODUCTION

The anterior area of the palate is widely used as an insertion site for orthodontic miniscrews. These temporary anchorage devices can be placed either directly or using an insertion guide, and various kinds of digital planning and guides are currently available. This study aimed to verify if the guided procedure can guarantee the correct position of the miniscrews on the patient compared with the digital project.

METHODS

Twenty-five consecutively treated patients were included in the study. Angular and linear displacements of the miniscrews were evaluated among 3 groups: the planned position, the model position, and the achieved position.

RESULTS

The median achieved angle between 2 digitally planned screws was 6.22° (interquartile range: 4.35°, 9.08°) and the difference between the angles in the planning and the achievement groups was significant (P <0.001). Lateral and vertical differences were also found among the 3 groups.

CONCLUSIONS

Results show that the examined workflow is clinically efficient. Differences between the digitally planned position of the orthodontic miniscrews, the control position, and the achieved position were detected both for angular and linear measurements but were not clinically significant.

Risk of root damage after using lateral cephalogram and intraoral scan for guided insertion of palatal miniscrews

Background

Guided insertion of palatal miniscrews using a lateral cephalogram instead of cone beam computed tomography (CBCT) significantly reduces the radiation level for the patient. Till now no data are available on the risk of hitting the incisors in this regard, which is one of the worst clinical complications when inserting a paramedian miniscrew. Hence, this study aims to investigate the distance between the mini-implant and the roots of the central and lateral incisors.

Methods

Lateral cephalogram, an intraoral scan, and CBCT of 20 patients were superimposed. After a miniscrew (1.7 × 8 mm) placement based on intraoral scan and lateral cephalogram, the CBCT was used as control for the distance between the miniscrews and the roots of the incisors.

Results

The mean value of the shortest distance between the miniscrew and roots of the incisors in the lateral cephalogram was 4.74 ± 1.67 mm. The distance between both miniscrews and the central incisors measured in the CBCT was 5.03 ± 2.22 mm and 5.26 ± 2.21 mm and between the two miniscrews and the lateral incisors was 4.93 ± 1.91 mm and 5.21 ± 2.64 mm. No significant differences between the distances in the CBCT and the lateral cephalogram could be observed. In one case, the CBCT control revealed the penetration of two palatally displaced canines after insertion based on intraoral scan and lateral cephalogram.

Conclusions

The use of an intraoral scan and a lateral cephalogram for guided paramedian insertion of palatal miniscrews can prevent incisor root damage. This may reduce the radiation since no CBCT seems necessary. The current investigation focuses on the anterior paramedian area of the palate. Outside that region and in complex cases with displaced teeth in the palatal area, a CBCT might be indicated.

Accuracy of the digital workflow for guided insertion of orthodontic palatal TADs: a step-by-step 3D analysis

Background

The introduction in the orthodontic field of the digital workflow for guided insertion of palatal TADs and the development of the 1-visit protocol led to the reduction of chair time and the possibility of complete customization of designs and materials. Conversely, the reduction of operative steps implicates a lower tolerance of deviations between the planned and the actual position of the miniscrews, particularly when the orthodontic device is fixed on 4 palatal TADs or has a rigid structure. This study aims to analyze the influence of each step of the digital workflow on the deviation of the miniscrews’ axis of insertion in a bicortical sample. The null hypothesis is that there are no significant differences in the deviations among the operative steps.

Methods

33 subjects were selected for insertion of bicortical palatal miniscrews with a 1-visit protocol. Digital files were collected at the three stages of the workflow (i.e., digital planning, laboratory prototype, post-insertion impression). A 3D software analysis was performed on a total of 64 miniscrews. After automatic shape recognition of the guiding holes of the digital plan and the scanbodies of the laboratory prototype and post-insertion impression as geometric cylinders, their three-dimensional longitudinal axis was traced and the deviation among them was calculated. Friedman test with Bonferroni correction was performed to assess the significance of the deviations among the three steps, with significance set at p < 0.05.

Results

The laboratory step has a significantly lower degree of deviations (2.12° ± 1.62) than both the clinical step (6.23° ± 3.75) and the total deviations (5.70° ± 3.42). No significant differences were found between miniscrews inserted on the left or the right side.

Conclusions

This study suggests that laboratory procedures such as surgical guide production or rapid prototyping don’t play a significant role in the degree of deviations between the planned and the positioned palatal TADs. Conversely, the clinical steps have a bigger influence and need to be carefully evaluated. Despite this difference, there is a cumulative effect of deviations that can lead to the failure of the 1-visit protocol.