Homemade CAD-CAM surgical guide for palatal mini-screw insertion for maxillary molar distalization providing anchorage. A two times original protocol / Pose de mini-vis palatines par chirurgie guidée à l'aide d'un guide CFAO in-office. Description d'un protocole original en deux temps.

Introduction: Temporary Anchorage Devices have revolutionized our approach to anchorage management. However, their placement may carry risks, such as root perforation, damage to the periodontal ligament, buccal-nasal communication, etc. The aim of this article is to describe an original protocol in two times for the placement of a palatal mini-screw through guided surgery using a guide created by Computer-Aided Design and Manufacturing (CAD/CAM) followed by the transfer of placement information to the laboratory for the fabrication of a Custom Medical Device (CMD) for distalization. Materials and Methods: A two-stage protocol is described and illustrated step by step. Phase 1 comprises 7 steps (including superimposition of maxillary cast and profile teleradiography, surgical tray design), followed by phase 2, which involves 3 final steps (including production of impression for laboratory, production of laboratory model with transfer of mini-screw position). Results: Although the position of the mini screws remains precise, a discrepancy between the planning and the intraoral situation exists. The addition of a second step therefore enables the distalization appliance to be fitted precisely and without pitfalls. Finally, this protocol ensures safe placement, making work easier for the practitioner and, ultimately, for the patient. Conclusion: In a two-stage process, the placement of palatal mini screws through guided surgery using a guide created by CAD/CAM followed by the transfer of this information to the laboratory for the fabrication of a CMD for distalization proves to be a relevant approach.

Introduction: Les dispositifs d'ancrage temporaires ont révolutionné notre vision de la gestion de l'ancrage. En revanche, leur mise en place peut comporter certains risques (perforation radiculaire, communication bucco-nasale, lésions vasculaires…). Cet article vise à décrire un protocole original, en deux temps, de pose de mini-vis palatine par chirurgie guidée à l'aide d'un guide réalisé par conception et fabrication assistée par ordinateur (CFAO) in-office suivie du transfert des informations de pose au laboratoire pour la confection d'un appareil de distalisation. Matériel et méthodes: Un protocole en deux temps est décrit pas à pas. Le temps 1 comprend sept étapes (dont le placement virtuel des mini-vis et la création de la gouttière chirurgicale), suivi du temps 2 qui implique trois étapes (dont la réalisation de l'empreinte pour le laboratoire et l'élaboration du modèle de laboratoire avec transfert de la position des mini-vis). Résultats: Bien que la pose puisse être considérée comme précise, une différence existe entre la planification et la situation clinique. L'apport d'un second temps améliore l'adaptation de l'appareil de distalisation. Enfin, ce protocole offre une pose sécurisée et apporte ainsi un confort de travail pour le praticien et, in fine, pour le patient. Conclusion: Réalisée en deux temps, la pose de mini-vis palatine par chirurgie guidée à l'aide d'un guide réalisé par CFAO in-office suivie du transfert de cette information au laboratoire pour la confection d'un appareil de distalisation s'avère être une approche pertinente.

Effects of exposure length, cortical and trabecular bone contact areas on primary stability of infrazygomatic crest mini-screws at different insertion angles.

BACKGROUND: The infrazygomatic crest mini-screw has been widely used, but the biomechanical performance of mini-screws at different insertion angles is still uncertain. The aim of this study was to analyse the primary stability of infrazygomatic crest mini-screws at different angles and to explore the effects of the exposure length (EL), screw-cortical bone contact area (SCA), and screw-trabecular bone contact area (STA) on this primary stability. METHODS: Ninety synthetic bones were assigned to nine groups to insert mini-screws at the cross-combined angles in the occlusogingival and mesiodistal directions. SCA, STA, EL, and lateral pull-out strength (LPS) were measured, and their relationships were analysed. Twelve mini-screws were then inserted at the optimal and poor angulations into the maxillae from six fresh cadaver heads, and the same biomechanical metrics were measured for validation. RESULTS: In the synthetic-bone test, the LPS, SCA, STA, and EL had significant correlations with the angle in the occlusogingival direction (rLPS = 0.886, rSCA = -0.946, rSTA = 0.911, and rEL= -0.731; all P < 0.001). In the cadaver-validation test, significant differences were noted in the LPS (P = 0.011), SCA (P = 0.020), STA (P = 0.004), and EL (P = 0.001) between the poor and optimal angulations in the occlusogingival direction. The STA had positive correlations with LPS (rs = 0.245 [synthetic-bone test] and r = 0.720 [cadaver-validation test]; both P < 0.05). CONCLUSIONS: The primary stability of the infrazygomatic crest mini-screw was correlated with occlusogingival angulations. The STA significantly affected the primary stability of the infrazygomatic crest mini-screw, but the SCA and EL did not.

[Comparison of the application of micro-implant screw support and flat guide plate in the treatment of excessive deep overbite of lower anterior teeth].

PURPOSE: To compare and analyze the orthodontic effects of micro-implant screw support and flat guide plate on excessive deep overbite of lower anterior teeth. METHODS: Eighty-two patients with excessive deep overbite of the lower anterior teeth who were treated from January to December 2022 were selected and randomly divided into two groups (41 in each group) by random number table method. Both groups were treated with straight wire arch orthodontic technology, and the anterior teeth were supported by micro-implant screws (micro-implant screw group) and flat guide plates (flat guide plate group), respectively. The effect of upper anterior tooth compression, changes in occlusal plane, and apical absorption were compared between the two groups. SPSS 25.0 software package was used for statistical analysis. RESULTS: There were no significant changes in SNA angle, SNB angle, ANB angle, U1-PP, U6-PP, and L6-MP before and after treatment between the two groups (P＞0.05). L1-MP significantly increased in both groups after treatment than before treatment(P＜0.05). There was no significant difference in bite opening, Spee curve depth, U1 depression, L1 depression, U6 elongation, L6 elongation and occlusal opening time between the two groups before and after treatment(P＞0.05). The root apex absorption of the mandibular central incisors and lateral incisors in the micro-implant screw group was significantly lower than that in the flat guide plate group(P＜0.05), while there was no significant difference in root apex absorption between the two groups of canines(P＞0.05). CONCLUSIONS: Both micro-implant screw support and flat guide plate can effectively lower the mandibular anterior teeth in the treatment of deep overbite in adults, with good orthodontic effects. However, the latter can lead to increased root resorption.

Variations in the alveolar bone morphology in maxillary molar area: a retrospective CBCT study.

BACKGROUND: This study quantitatively analyzed the anatomic structure of the alveolar bone in the maxillary molar region at three potential locations for Temporary Anchorage Device (TAD) placement. Additionally, the study compared the variability in this region across different age groups, sagittal skeletal patterns, vertical facial types, and sexes. METHODS: In this retrospective cone-beam computed tomography study, the buccal alveolar bone was analyzed in the posterior molar area of 200 patients, the measurement items include buccal alveolar bone height, alveolar bone thickness, interradicular distance, and maxillary retromolar space. RESULTS: Buccal alveolar height was greatest in the U56 region. The interradicular space was largest in the U56 region and increased from the alveolar crest to the sinus floor. Buccal alveolar bone thickness was highest in the U67 region and generally increased from the alveolar crest to the sinus floor. The maxillary retromolar space gradually increased from the alveolar crest to the root apex. CONCLUSIONS: TADs are safest when placed in the buccal area between the maxillary second premolar and the first molar, particularly at the 9 mm plane. The U67 region is the optimal safe zone for TAD placement for maxillary dentition distalization. TADs placement in adolescents can be challenging. Maxillary third molar extraction can be considered for maxillary dentition distalization.

The use of miniplates for nontraditional orthodontic treatment: clinical considerations for referring general dentists.

Distalization of mandibular molars comes with significant challenges, especially in adult and young adult patients. In selected cases, third molar extraction procedures offer the opportunity to place miniplates for anchorage to distalize mandibular molars, providing additional solutions to the traditional extraction of premolars or a single incisor. This approach can be of special interest to adult patients, who may have life commitments and time restraints that limit traditional orthodontic and surgical treatment options, and it can improve the efficiency of dental care. This case series describes 3 clinical scenarios in which miniplates were placed with minimal invasiveness during the removal of impacted third molars, offering the patients nontraditional orthodontic treatment options. Awareness of these options is essential for general dentists so that they can explain all treatment possibilities and provide appropriate referrals to patients with impacted third molars.

MISMARPE protocol: minimally invasive surgical and miniscrew-assisted rapid palatal expansion.

OBJECTIVE: The purpose of this article is to present the MISMARPE technique, a new minimally invasive surgical procedure to treat maxillary transverse atresia in adult patients under local anesthesia and on an outpatient basis. TECHNIQUE DESCRIPTION: The technique consists of miniscrew-assisted rapid palatal expansion (MARPE) associated with a minimally invasive approach using maxillary osteotomies, latency and activation periods until the desired expansion is achieved. The present MISMARPE technique was performed in 25 consecutive cases with a success rate of 96%, yielding good skeletal outcomes with minimal trauma. The expander appliances, with their anchorage types, and a description of the surgical steps of the MISMARPE technique are presented. CONCLUSION: MISMARPE is a new and effective alternative for less invasive treatment of maxillary transverse deficiency in adults, compared to conventional surgery. Emphasis is placed on the importance of systematic and well-established protocols, for executing the procedures safely and predictably.

Miniscrew-assisted rapid palatal expansion (MARPE): Factors influencing planning.

OBJECTIVE: This cross-sectional study evaluated the bone thickness on mini-implants insertion site, the factors that influence the digital planning of MARPE appliance (miniscrew-assisted rapid palatal expansion), and its different designs. METHODS: A total of 135 plannings were assessed regarding the size of the expander screw used, the positioning and the type of the mini-implant rings, and their location in relation to the teeth. Bone thickness measurements were assessed in the region of the mini-implants' trajectory. Differences between the sexes was verified using the ANOVA test (5% significance). RESULTS: 73 cases were planned with 4 mini-implants and 62 cases, with 6 mini-implants. In 90% of cases, teeth #16 and #26 were used as supports, and the most used expander screw was 13mm (64.1% of cases). The anterior mini-implants of conventional MARPE showed more pronounced insertion in bone in males (5.9 ± 2mm; p= 0.025). The extra mini-implants (anterior region) were inserted with greater bone thickness in males (11.1 ± 2.3mm) compared to females (9.9 ± 1.8mm; p=0.041). A greater bone thickness was observed in males (10.1 ± 2.1 mm) when using mini-implants in the paramedian region. CONCLUSION: Additional rings allow more pronounced bone insertion. Male patients had greater bone thickness, which may be related to greater difficulty in opening the sutures. The alveolar process region seems to be a satisfactory site for mini-implants to those patients with reduced bone thickness in the paramedian posterior region. MARPE appliance must be customized for each patient, due to bone thickness and anatomical variations.

Three-dimensional assessment of low-level laser therapy on orthodontic miniscrew displacement using CBCT: a retrospective study.

BACKGROUND: This study aimed to assess the effect of Low-Level Laser Therapy (LLLT) on sagittal, transverse and vertical Orthodontic miniscrew displacement. MATERIALS AND METHODS: The study included CBCTs from the records of 12 adult patients who underwent upper first premolar extraction and canine retraction with orthodontic miniscrews for maximum anchorage. The miniscrews on one side received LLL, while the other side served as a control. The Low-Level Laser was applied to assess its effect on the displacement of the miniscrews. The used CBCTs have been taken at two-time points: immediately after miniscrew insertion (T0) and four months after the start of canine retraction (T1) with a total of 24 CBCTs. Miniscrew displacement was assessed by measuring head (HMS) and tail (TMS) displacement to the axial, coronal and mid-sagittal planes on the CBCT at the two time points. Miniscrews displacement (T1-T0) was compared between LLL side and control side. Comparisons were performed using paired samples t-test. The significance level was set at p-value < 0.05. The reproducibility of measurements was assessed by intraclass correlation coefficient (ICC). RESULTS: After four months of canine retraction, HMS and TMS from both laser and control sides showed significant three-dimensional displacement at p < 0.05. No significant difference in mean displacement in the vertical, sagittal, nor transverse planes between both sides was elicited. CONCLUSION: LLL application in the used protocol does not affect the amount of miniscrew displacement in any of the three planes of space. Miniscrew displacement was significant in both groups.

Investigating adhesion of primary human gingival fibroblasts and osteoblasts to orthodontic mini-implants by scanning electron microscopy.

Miniscrews offer controlled anchorage and thus optimize tooth movement in orthodontic treatment. Nevertheless, failures such as soft tissue problems, instability due to loosening, partial osseointegration, or even device fracture can occur. While clinical technique can play a role in some of these problems, the manufacturer's design and material choice influence how the implant interacts with the surrounding tissue. In some cases, the design and material may trigger unwanted bone and soft tissue responses. This in vitro study investigates how the implant surface affects cell adhesion and growth of human primary fibroblasts and osteoblasts on commercially available orthodontic TiAl6V4 miniscrews from three producers: tomas-pin SD N 08 (Dentaurum), OrthoEasy Pin (Forestadent), and Dual Top G2 (Promedia, Jeil Medical). Cell-implant interaction at the top, neck, and drilling part of the screws was assessed qualitatively by scanning electron microscopy. While both cell types adhered to and grew on all products, subtle differences in cell shape and spreading were detected, depending on the microstructure of the implant surface. This indicates that cell adhesion to implant surfaces can be controlled by manipulating the machining conditions.

Control of anterior anchorage with miniscrews and sliding mechanics in an adolescent with missing second premolars: A clinical report with biomechanical validation.

Congenital missing second premolars in growing patients should be accurately evaluated in order to establish a suitable treatment plan. Concerning the decision of whether to close or maintain spaces in the dental arches, it shall also be based on biomechanical aspects and the aesthetic traits of individual patients. Accordingly, the option of closing tooth spaces requires an adequate application of biomechanical principles aimed at avoiding detrimental effects on dental arches and facial profile. An effective use of titanium miniscrews for immediate loading, associated with efficient sliding mechanics, can represent an elective way to successfully treat such cases. Herein, the objective is to describe the procedure and underscore the advantages of the mentioned approach by presenting a clinical case along with long-term follow-up.

Friction versus frictionless mechanics during maxillary en-masse retraction in adult patients with Class I bimaxillary dentoalveolar protrusion: a randomized clinical trial.

BACKGROUND: Extraction space closure is a challenging phase during orthodontic treatment that affects not only the total treatment duration but also the whole treatment outcome. OBJECTIVE: To compare the efficiency of friction and frictionless mechanics during en-masse retraction of maxillary anterior teeth in adult patients with bimaxillary dentoalveolar protrusion. TRIAL DESIGN: Two-arm parallel group, single-center randomized clinical trial. MATERIALS AND METHODS: Thirty-two adult patients with bimaxillary protrusion were recruited and randomly allocated to two different retraction mechanics. A friction group, using NiTi coil springs and a frictionless group using closing T-loops for en-masse retraction. Randomization in a 1:1 ratio was generated by Microsoft Excel. The randomization numbers were secured in opaque sealed envelopes for allocation concealment. Retraction started in all patients following first premolars extraction using miniscrews as a source of indirect anchorage. Activation was done on a monthly basis until complete retraction of anterior segment. The rate of retraction, amount of anchorage loss, the dental, and soft tissue changes were analyzed on digital models and lateral cephalograms taken before retraction and after space closure. BLINDING: The outcome assessor was blinded through data concealment during assessment. RESULTS: Two patients were lost to follow up, so 30 patients completed the trial. The rate of anterior segment retraction was 0.88 ±â€…0.66 mm/month in the frictionless group compared to 0.72 ±â€…0.36 mm/month in the friction group which was statistically significant. Anchorage loss of 1.18 ±â€…0.72 mm in the friction group compared to 1.29 ±â€…0.55 mm in the frictionless group with no significant difference. Comparable dental and soft tissue changes following en-masse retraction were reported in both groups, with no statistically significant difference. HARM: one patient complained of soft tissue swelling following miniscrew insertion, but the swelling disappeared after one week of using mouth wash. LIMITATION: The study focused only on the maxillary arch. CONCLUSION: Both mechanics have successfully achieved the required treatment objectives in patients with bimaxillary dentoalveolar protrusion. Frictionless group showed a faster rate of retraction than the friction group, which was statistically but not clinically significant. TRIAL REGISTRATION: Clinicaltrials.gov with the identifier NCT03261024.

Effect of cortical bone thickness on shear stress and force in orthodontic miniscrew-bone interface - A finite element analysis.

Miniscrews are widely used in orthodontics as an anchorage device while aligning teeth. Shear stress in the miniscrew-bone interface is an important factor when the miniscrew makes contact with the bone. The objective of this study was to analyze the shear stress and force in the screw-bone interface for varying Cortical Bone Thickness (CBT) using Finite Element Analysis (FEA). Varying CBT of 1.09 mm (1.09CBT) and 2.66 mm (2.66CBT) with miniscrews of Ø1.2 mm, 10 mm length (T1), Ø1.2 mm, 6 mm length (T2) and Ø1.6 mm, 8 mm length (T3) were analyzed. Six Finite Element (FE) models were developed with cortical, cancellous bone, miniscrews and gingiva as a prism. A deflection of 0.1 mm was applied on the neck of the miniscrews at 0°, +30° and -30° angles. The shear stress and force in the screw-bone interface were assessed. The results showed that the CBT affects the shear stress and force in the screw-bone interface region in addition to the screw dimensions and deflection angulations. T1 screw generated lesser shear stress in 1.09CBTand 2.66CBTcompared to T2 and T3 screws. Higher CBT is preferred for better primary stability in shear aspect. Clinically applied forces of 200 gms to 300 gms to an anchorage device induces shear stress in the miniscrew-bone interface region might cause stress shielding. Thus, clinicians need to consider the effect of varying CBT and the size of the miniscrews for the stability, reduced stress shielding and better anchorage during orthodontic treatment.

Effectiveness of different intrusion modes of maxillary anterior teeth with mini-implants in clear aligner treatment: a three-dimensional finite element analysis.

BACKGROUND: The intrusion of maxillary anterior teeth is often required and there are various intrusion modes with mini-implants in clear aligner treatment. The objective of this study was to evaluate the effectiveness of maxillary anterior teeth intrusion with different intrusion modes, aiming to provide references for precise and safe intrusion movements in clinical practice. METHODS: Cone-beam computed tomography and intraoral optical scanning data of a patient were collected. Finite element models of the maxilla, maxillary dentition, periodontal ligaments (PDLs), clear aligner (CA), attachments, and mini-implants were established. Different intrusion modes of the maxillary anterior teeth were simulated by changing the mini-implant site (between central incisors, between central and lateral incisor, between lateral incisor and canine), loading site (between central incisors, on central incisor, between central and lateral incisor, between lateral incisor and canine), and loading mode (labial loading and labiolingual loading). Ten conditions were generated and intrusive forces of 100 g were applied totally. Then displacement tendency of the maxillary anterior teeth and CA, and stress of the PDLs were analyzed. RESULTS: For the central incisor under condition L14 and for the canine under conditions L11, L13, L23, and L33, the intrusion amount was negative. Under other conditions, the intrusion amount was positive. The labiolingual angulation of maxillary anterior teeth exhibited positive changes under all conditions, with greater changes under linguoincisal loading. The mesiodistal angulation of canine exhibited positive changes under labial loading, while negative changes under linguoincisal loading except for condition L14. CONCLUSIONS: The intrusion amount, labiolingual and mesiodistal angulations of the maxillary anterior teeth were affected by the mini-implant site, loading site, and loading mode. Labial and linguoincisal loading may have opposite effects on the intrusion amount of maxillary anterior teeth and the mesiodistal angulation of canine. The labiolingual angulation of the maxillary incisors would increase under all intrusion modes, with greater increases under linguoincisal loading.

Dentoalveolar, periodontal and skeletal effects of maxillary expansion techniques assisted by temporary anchorage devices compared with conventional protocols in growing patients with transverse maxillary deficiency: A systematic review and meta-analysis.

OBJECTIVES: To synthesise the dentoalveolar, periodontal and skeletal changes that occur when using maxillary expansion techniques assisted by temporary anchorage devices compared to conventional protocols. METHODS: Five databases and grey literature were consulted, up to December 2023, focusing on intervention designs and excluding other type of studies. The quality assessment was conducted by using the adaptation for orthodontics of the CONSORT statement, the guidelines for reporting non-randomised studies, the RoB-2 tool, and the ROBINS-I tool. A descriptive summary and meta-analysis using RevMan 5.4 were performed. RESULTS: Nine clinical trials were included (n=377 patients, mean age 13.2±0.6) with a diagnosis of transverse maxillary deficiency. The analysed studies showed qualitative dentoalveolar and periodontal changes after expansion, which were greater on the maxillary first premolars in tooth-borne appliances. Meta-analyses for some effects were included from two studies (n=64); patients who used tooth-borne appliances had greater effects of buccal intercoronal width between the premolars with statistically significant differences (Std Mean difference 2.34; 95% CI: 0.04-4.65 p=0.05). Conversely, those patients who used bone-borne or hybrid appliances had greater effects of buccal intercoronal width between molars with statistically significant differences (Std Mean difference -0.64; 95% CI: -1.38-0.10; p=0.09). CONCLUSIONS: According to the studies analysed, all measurements increased in the intervention groups after expansion. Quantitative analyses show different findings at dentoalveolar level when tooth-borne, bone-borne or hybrid appliances are considered. Nevertheless, the results should be taken with caution due to the heterogeneity of the studies. The protocol was registered at PROSPERO (CRD42021283170), with no funding to report.

The efficiency of a customized distalizer with Variety SP® screws anchored on palatal miniscrews for upper molar distalization.

OBJECTIVE: To assess the effectiveness of a customized distalizer with Variety SP® screws anchored on palatal miniscrews for upper molar distalization. METHODS: Seventeen patients aged between 12.5 and 24 years underwent distalization with a customized distalizer. Lateral cephalogram and cast analysis were performed before and after distalization. Linear and angular parameters of the upper first molar, first premolar, and central incisor were assessed. RESULTS: Distalization with the force passing near the center of resistance (CRes) of the upper first molars resulted in distal movement, with minimal distal tipping (2.8 ±â€Š0.45°, p< 0.05). However, distalization passing occlusal to the CRes led to greater distal tipping (13.6 ±â€Š1.63°, p< 0.05). Statistically significant spontaneous distal tipping and distal movement of the upper first premolars occurred, with a mean of 6.2 ±â€Š1.24° (p< 0.05) and 0.68 ±â€Š0.34 mm (p< 0.05), respectively. The positional change of the upper central incisors presented a mean of -0.23 ±â€Š0.1 mm (p> 0.05) and 2.65 ±â€Š1.1° (p< 0.05). Upper first molar intrusion was statistically significant, with a mean of 0.88 ±â€Š0.2 mm (p< 0.05). Upper right and left first molars rotation towards palatal midline presented mean of 4.1 ±â€Š0.19° (p< 0.05) and 3.4  ±â€Š0.1° (p< 0.05), respectively. Additionally, the distance between upper right and left first molars increased significantly, with a mean of 2.54 ±â€Š0.01 mm (p< 0.05). CONCLUSION: The study successfully demonstrated the efficiency of molar distalization without anchorage loss using a customized distalizer anchored on palatal miniscrews.

How palatal vault morphology and screw length influence the accuracy of dynamic computer-guided orthodontic miniscrew insertion. A prospective clinical study.

OBJECTIVES: The aim of this study was to evaluate the influence of palatal vault morphology and screw length on the accuracy of miniscrew insertion in dynamic computer-assisted surgery (d-CAS). METHODS: Twenty-four subjects were allocated into three groups, according to their palatal vault morphology (Group A: medium; Group B: steep/high; Group C: low/flat) and the length of miniscrew used. For each subject, two miniscrews were inserted using a dynamic navigation system. To assess the accuracy of insertion, a postoperative CBCT was performed, and the pre- and post-operative scans were superimposed. Five variables were evaluated: Entry-3D, Entry-2D, Apex-3D, Apex-vertical and angular deviation. Descriptive statistics, Shapiro-wilk, Kruskal-Wallis and Dunn's tests were used for the statistical analysis. The level of significance was P ≤ 0.05. RESULTS: The mean angular deviation values revealed strong discrepancies amongst the groups (Group A:7.11°±5.70°; Group B:13.30°±7.76°; Group C:4.92°±3.15°) and significant differences were found regarding the Apex-3D (P = 0.036) and angular deviations (P = 0.008). A Dunn's test revealed differences in angular deviation between the medium and high/steep palate group (P = 0.004), and between low/flat and high/steep palate group (P = 0.01) but did not confirm any significant difference in the Apex-3D parameter (Group A-B P = 0.10; Group B-C, P = 0.053; Group A-C, P = 1.00). No significant differences were found regarding the length of the miniscrews. CONCLUSIONS: Palatal vault morphology is a factor that influences the accuracy of miniscrew insertion in d-CAS. In subjects with steep and high palatal vaults, insertion accuracy is lower when considering the angular deviation value. Miniscrew length does not influence accuracy. CLINICAL SIGNIFICANCE: Although computer-guided surgery assists the clinician in preventing damage to nearby anatomical structures, individual anatomical variability is a crucial variable. In subjects with a high/steep palate, greater attention should be paid during the planning phase in order to allow for a wide margin from adjacent anatomical structures to achieve better outcomes.

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".