Is there an ideal insertion angle and position for orthodontic mini-implants in the anterior palate? A CBCT study in humans

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.

Periodontal evaluation after maxillary expansion with a tooth-bone-borne expander in growing patients : A randomized clinical trial

PURPOSE

This two-arm parallel randomized controlled trial aimed to evaluate and compare periodontal changes due to rapid maxillary expansion (RME) using tooth-bone-borne and tooth-borne devices in growing patients via clinical examinations and cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Forty-two eligible patients (aged 11-14 years; transverse maxillary deficiency, posterior crossbite) were screened and divided into two groups based on the treatment received (randomization was performed using computer-generated numeric sequences): hybrid hyrax tooth-bone-borne group (TBB) and hyrax tooth-borne group (TB). The primary outcome was the change in cortical bone thickness (by CBCT). In addition, the clinical attachment level (CAL), gingival recession, and bleeding were assessed. Both examinations were performed before and 3 months after the activation phase. Intergroup comparisons were performed using analysis of covariance (ANCOVA; P < 0.05).

RESULTS

Twenty-one patients (12 girls and 9 boys; mean initial age, 13.3 years) were included in the TBB group and 21 (5 girls and 16 boys; mean initial age, 13.2 years) were included in the TB group. The TB group exhibited a decrease in buccal bone thickness in the first premolars and first molars at all three evaluated levels. Specifically, tooth 14 at 3 mm from the enamel-cement junction showed a significant width reduction (0.7 mm; p < 0.001), accompanied by a notable increase in palatal cortical thickness at 6 mm of enamel-cement junction (1.13 mm; p < 0.001).

CONCLUSIONS

RME resulted in buccal bone thickness reduction at the first premolar with hyrax treatment. In the molar region, both devices resulted in cortical bone alterations that were less pronounced in the TBB group.

Mini-Implant Insertion Using a Guide Manufactured with Computer-Aided Design and Computer-Aided Manufacturing in an Adolescent Patient Suffering from Tooth Eruption Disturbance

Due to dental diseases, anatomical restrictions, and mixed dentition, the reduction in the number of teeth and the displacement of tooth germs pose challenges in orthodontic treatment, limiting anchorage options. The presented case demonstrates an advanced treatment solution using digital CAD/CAM-technologies and medical imaging for the creation of a mini-implant template. A 12-year-old male patient experiencing delayed tooth eruption, multiple impacted germs, and maxillary constriction underwent intraoral scanning and CBCT. Utilizing coDiagnostiXTM Version 10.2 software, the acquired data were merged to determine the mini-implant placement and to design the template. The template was then manufactured through stereolithography using surgical-guide material. Mini-implants were inserted using the produced appliance, enabling safe insertion by avoiding vital structures. Surgically exposed displaced teeth were aligned using a Hyrax screw appliance anchored on the mini-implants for rapid palatal expansion (RPE) and subsequently used as fixed orthodontics to align impacted teeth. The screw was activated daily for 10 weeks, resulting in a 7 mm posterior and 5 mm anterior maxillary transversal increase. Skeletal anchorage facilitated simultaneous RPE and tooth alignment, ensuring accuracy, patient safety, and appliance stability. The presented case shows a scenario in which computer-aided navigation for mini-implant positioning can enhance precision and versatility in challenging anatomical cases.

Impact of different cephalometric skeletal configurations on anatomic midface parameters in adults

OBJECTIVES

Skull morphology and growth patterns are essential for orthodontic treatment, impacting clinical decision making. We aimed to determine the association of different cephalometric skeletal configurations on midface parameters as measured in 3D CT datasets.

MATERIALS AND METHODS

After sample size calculation, a total of 240 fully dentulous patients between 20 and 79 years of age (mean age: 42 ± 15), who had received a CT of the skull within the scope of trauma diagnosis or intracranial bleeding, were retrospectively selected. On the basis of cephalometric analysis, using MPR reconstructions, patients were subdivided into three different vertical skull configurations (brachyfacial, mesofacial, dolichofacial) and the respective skeletal Class I, II, and III relationships. Anatomic parameters were measured using a three-dimensional post-processing console: the thickness of the maxillary and palatine bones as well as the alveolar crest, maxillary body and sutural length, width and height of the hard palate, maxillary facial wall thickness, and masseter muscle thickness and length.

RESULTS

Individuals with brachyfacial configurations had a significantly increased palatal and alveolar ridge thicknesses compared to those with dolichofacial- or mesofacial configurations. Brachyfacial configurations presented a significantly increased length and thickness of the masseter muscle (4.599 cm; 1.526 cm) than mesofacial (4.431 cm; 1.466 cm) and dolichofacial configurations (4.405 cm; 1.397 cm) (p < 0.001). Individuals with a skeletal Class III had a significantly shorter palatal length (5.313 cm) than those with Class I (5.406 cm) and Class II (5.404 cm) (p < 0.01). Sutural length was also significantly shorter in Class III (p < 0.05).

CONCLUSIONS

Skeletal configurations have an impact on parameters of the bony skull. Also, measurable adaptations of the muscular phenotype could result.

CLINICAL RELEVANCE

The association between viscerocranial morphology and midface anatomy might be beneficial for tailoring orthodontic appliances to individual anatomy and planning cortically anchored orthodontic appliances.

Short-term assessment of pain and discomfort during rapid maxillary expansion with tooth-bone-borne and tooth-borne appliances: randomized clinical trial

OBJECTIVE

The aim of this randomized clinical trial was to evaluate and compare, during the first week of rapid maxillary expansion (RME), the impact caused by two types of appliances: Hyrax and Hybrid Hyrax.

METHODS

Forty-two patients who met the eligibility criteria (aged 11-14 years, with transverse maxillary deficiency, posterior crossbite, and presence of maxillary first premolars and first permanent molars) were selected and randomly divided into two groups: TBB GROUP (tooth-bone-borne expander), treated with Hybrid Hyrax (12 females and 9 males, mean age 13.3 ± 1.3 years), and TB GROUP (tooth-borne expander), treated with Hyrax (5 females and 16 males, mean age 13.3 ± 1.4 years). Pain and discomfort were assessed in two times: after the first day of activation (T1) and four days after, by means of the numerical rate scale and the instrument MFIQ (Mandibular Functional Impairment Questionnaire). Descriptive statistics and the Mann-Whitney test were used for comparison between groups and between sexes. A 5% significance level was adopted.

RESULTS

Both appliances had a negative impact, generating pain and discomfort, and reducing functional capacity. However, the scores obtained were of low intensity and no significant differences were observed between the groups. Considering sexes, there were statistically significant differences, with the female sex presenting higher scores for pain and functional limitation.

CONCLUSIONS

Despite causing impact in pain and increase in the functional limitation, these changes were of low intensity, with no statistical difference between the groups. Females were more sensitive to the impact caused by the RME.

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.

Dentofacial effects of miniscrew-anchored maxillary protraction on prepubertal children with maxillary deficiency: a randomized controlled trial

BACKGROUND

The introduction of bone-anchored maxillary protraction eliminated the side effects of facemask in the early treatment of patients with maxillary retrusion. This study aimed to evaluate the effects of miniscrew-anchored maxillary protraction (MAMP) and compare them with the growth changes in an untreated control group in growing patients with Class III malocclusion.

METHODS

Forty growing patients with Class III malocclusion and retrognathic maxilla were randomly allocated into two groups: treated and control groups. In the treated group, patients were treated with full-time intermaxillary Class III elastics (C3E) anchored by a hybrid hyrax (HH) in the maxilla and a bone-supported bar in the mandible. Protraction was stopped after obtaining a positive overjet. Cephalometric radiographs were acquired before and after the treatment. Data were statistically analyzed on an intention-to-treat basis. Intergroup comparisons were also made using analysis of covariance with the readings at T0 as a covariate.

RESULTS

Forty patients agreed to participate, and 30 of them completed the study (treated group, n = 17; control group, n = 13). The average treatment duration was 11.9 months. MAMP resulted in a significant maxillary advancement (A-VR, 4.34 mm) with significant control over the mandibular growth. No significant increase in the mandibular plane angle was found in the treated group compared with the control group. The upper and lower incisors showed significant protrusion in the treated group.

CONCLUSIONS

Within the limitations of this study and high attrition rate, the MAMP protocol can effectively increase maxillary forward growth with good control over the growth of the mandible antero-posteriorly and vertically.

Palatal bone thickness for mini-implant insertion in different vertical growth patterns: a systematic review

Introduction

The purpose of this systematic review was to identify, evaluate, and provide information about palatal bone thickness in different vertical growth patterns for the placement of orthodontic anchorage devices.

Methods

We performed a systematic review of the published data in Medline via PubMed, Web of Science, Cochrane Library, and Scopus from January 2000 to August 2022 using eligibility criteria. Data collection analysis and data extraction were performed independently by three reviewers. Sensitivity analyses were performed with the Cochrane risk of bias tool and the ROBINS-I tool was used for non-randomized studies.

Results

A total of 343 articles were identified. The inclusion criteria included palatal bone thickness and vertical facial growth. However, both variables were found in 4 studies and only 2 had a control group. The different studies evaluated palatal bone thickness according to sex (male 14.1 mm; female 9.68 mm) and vertical malocclusion (normal 2.2 -12.6 mm; open bite 1.9 -13.2mm) with heterogeneous results. Likewise, the vertical growth pattern with a low angle (9.39 mm) was greater than the normal (8.55 mm) and high angle (7.53 mm).

Conclusions

Palatal bone thickness varies according tp different vertical growth patterns, with the greatest thickness being found near the incisive foramen in hypodivergent individuals.

Comparison of 3 different bone-borne type expansion appliances used in surgically-assisted rapid palatal expansion: A finite element analysis

INTRODUCTION

This study aimed to compare the effects of 3 different bone-borne type expansion appliances used in the surgically-assisted rapid palatal expansion (SARPE) by finite element analysis.

METHODS

Three different miniscrew-supported palatal expansion appliances were modeled. Median and lateral osteotomies were performed without pterygomaxillary suture separation. Model I consisted of a palatal expander with 2 miniscrews placed 4 mm far from the midpalatal suture. In model II, 2 miniscrews were located at the alveolar ridge between the first molar and the second premolar. In model III, 4 miniscrews were placed as a combination of the first and second models. Stress distributions and amount of displacements were evaluated with Ansys software (version 19.2; Ansys, Canonsburg, Pa) for 5-mm expansion in a symmetrical finite element analysis model to reflect the clinical situation.

RESULTS

SARPE simulation using miniscrew-assisted maxillary expanders for all models showed a rotation and tipping of the maxilla. The largest displacement was found for the anterior part of the palate in model II and the posterior part in model III. Although a wedge-shaped expansion pattern was observed in all models, this form was more prominent in model II. The highest stress value (0.91 MPa) was measured in model I, and the lowest value (0.004 MPa) was measured in model II for the anterior nasal spine region. The highest stress value (0.51 MPa) was measured in model III, and the lowest value (0.12 MPa) was measured in model II for the posterior nasal spine region. The lowest stress values were measured in model II for all the craniofacial and maxillofacial structures.

CONCLUSIONS

Among the models, the lowest stress distribution conditions for craniofacial and maxillofacial structures were found in model II. The largest displacement was found at the incisors and anterior part of the maxilla for model II. The greatest displacement was found at the posterior region for model III.

Analysis of factors associated with the success of microimplant-assisted rapid palatal expansion

INTRODUCTION

Success-related factors of microimplant-assisted rapid palatal expansion (MARPE) were evaluated, including age, palatal depth, suture, and parassutural bone thickness, suture density and maturation, and the relation to corticopuncture (CP) technique, as well as skeletal and dental effects.

METHODS

Sixty-six cone-beam computed tomography scans were analyzed before and after rapid maxillary expansion procedures in 33 patients aged 18-52 years for both sexes. The scans were generated in digital imaging and communications in medicine file format and analyzed in the multiplanar reconstruction of the regions of interest. Palatal depth, suture thickness, density and maturation, age, and CP were assessed. To evaluate dental and skeletal effects, the sample was divided into 4 groups: successful MARPE (SM), SM + CP technique (SMCP), failure MARPE (FM), and FM + CP (FMCP).

RESULTS

Successful groups presented more skeletal expansion and dental tipping than failure groups (P <0.05). The mean age of the FMCP group was significantly higher than the SM groups; suture and parassutural thickness significantly related to the success, and patients who received CP showed a success rate of 81.2% compared with 33.3% in the no CP group (P <0.05). Suture density and palatal depth did not show a difference between the success and failure groups. Suture maturation was higher in SMCP and FM groups (P <0.05).

CONCLUSIONS

Older age, thin palatal bone, and higher stage of maturation can influence the success of MARPE. CP technique in these patients appears to have a positive impact, increasing the chance of treatment success.

A retrospective comparison of two protocols for correction of skeletal Class III malocclusion in prepubertal children: hybrid hyrax expander with mandibular miniplates and rapid maxillary expansion with face mask

BACKGROUND

This study compared the skeletal and dental effects of a hybrid maxillary expander with mandibular miniplates (HE-MP) and Class III elastics to conventional tooth-borne rapid maxillary expander and face mask (RME-FM) in skeletal Class III treatment.

METHODS

This retrospective study included 36 skeletal Class III patients. Eighteen patients (mean age 10.24 ± 1.31 years) were treated with a hybrid expander, two mandibular L-shaped miniplates and full-time Class III elastics (HE-MP group). Their results were compared to a group of patients treated with conventional RME-FM (n = 18; mean age 10.56 ± 1.41 year). Radiographs were taken before (T1) and after treatment (T2). All patients were in cervical maturation stages CS1-CS3 at T1. The measured outcomes were the changes in sagittal and vertical skeletal and dental cephalometric measurements.

RESULTS

Treatment time was approximately 15.5 ± 2.8 months with the HE-MP and 11.85 ± 3.41 months for the RME-FM. The Class III malocclusion was corrected in both groups with significant changes. The maxilla advanced more in the HE-MP group, with an increase in SNA of 4.26° ± 2.15° compared to 1.14 ± 0.93 in the RME-FM group (p < 0.001). The effect on the mandible was similar in both groups, while the overall skeletal change was significantly greater with HE-MP, with an increase in the ANB of 5.25° ± 2.03° and a Wits appraisal increase of 6.03 ± 3.13 mm, as opposed to 2.04° ± 1.07° and 2.94 ± 1.75 mm with the RME-FM (p < 0.001). Dental changes were significantly higher with RME-FM, with an increase in incisor inclination (U1-SN) of 5.02° ± 3.93° (p < 0.001), with no significant changes in the HE-MP group. The mandibular incisors retroclined by 5.29° ± 3.57° at L1-MP with the RME-FM, while they advanced slightly with the HE-MP by 2.87° ± 5.37° (p < 0.001).

CONCLUSION

The use of skeletal anchorage for maxillary expansion and protraction significantly increases skeletal effects and reduces dental side effects compared to tooth-borne maxillary expansion and protraction. These results need to be investigated in the long term.

Dentoskeletal changes due to rapid maxillary expansion in growing patients with tooth-borne and tooth-bone-borne expanders: A randomized clinical trial

OBJECTIVES

To compare, using cone-beam computed tomography, the dentoskeletal changes in rapid maxillary expansion with tooth-bone-borne (Hybrid Hyrax) and tooth-borne (Hyrax) appliances.

SETTING AND SAMPLE POPULATION

Forty-two patients who met the eligibility criteria (aged 11-14 years; transverse maxillary deficiency, posterior crossbite, and presence of upper first premolars and molars) were screened and allocated into two groups: HHG (treatment with Hybrid Hyrax) and HG (treatment with Hyrax).

MAIN OUTCOME MEASURES

The primary outcomes included nasomaxillary dimensional changes. CBCT was performed before and 3 months after the activation phase. Measurements were performed using Dolphin® . Baseline data were compared using one-way ANOVA. For intergroup comparison, ANCOVA was used to analyze the initial age, appliance activations (mm), and mid-palatal suture maturation data as covariates. Statistical significance was set at 5%.

RESULTS

The premolar region in HHG showed increased skeletal changes than in HG, with the difference being 1.5 mm (0.5; 2.6) in the nasal cavity (P = .004), 1.4 mm (0.3; 2.5) in the nasal floor (P = .019), and 1.1 mm (0.2; 2.1) in the maxilla (P = .022). The molar region in HHG showed increased skeletal changes with the difference being 0.9 mm (0.2; 1.5) in the nasal cavity (P = .005), and 0.9 mm (0; 1.8) in the maxilla (P = .042) than in HG. Premolar inclination was higher in HG.

CONCLUSION

Hybrid Hyrax showed more skeletal changes and fewer dental side effects, especially in the first premolar region. The amount of activation influenced the higher nasal skeletal changes in the Hybrid hyrax group.

A Novel Method to Combine Maxilla-Based Coordinate System and Mandibular Voxel-Based Superimposition with Cone-Bean Computed Tomography

Background: The objective of this study was to propose a method that combines a maxilla-based coordinate system and mandibular voxel-based superimposition for an accurate evaluation of mandibular structural and positional changes and a direct comparison between maxillary and mandibular structural changes with the same 3D vectors. Methods: Mandibular voxel-based superimposition was firstly performed to reorient the mandibles and eliminate the mandibular positional changes. Then, a maxilla-based coordinate system was constructed with four maxillary skeletal landmarks (ANS, PNS, OrL and OrR). After settling the reoriented mandibles into this coordinate system, the mandibular structural changes were accurately evaluated. To assess the accuracy and reproducibility of this method, CBCT images of a skull specimen before and after orthodontic treatment (which was simulated by rearranging the skull and the mandible) were collected. Five mandibular skeletal landmarks, three mandibular dental landmarks and two mandibular measurement planes of this skull were used to evaluate the linear and angular changes in the mandibular structures. Results: There were significant differences in the linear and angular measurements of the mandibular structures of the skull (p ˂ 0.05), which indicated mandibular positional changes after orthodontic treatment. After mandibular voxel-based superimposition, there were no significant differences in the linear and angular measurements of mandibular structures, which indicated that the mandibular positional changes were eliminated. The intraclass correlation coefficient (ICC) value of the inter- and intra-observer agreement of all measurements was 0.99. Conclusions: This method has proven advantages in terms of accuracy, reproducibility and validity; with this method, mandibular structural and positional changes can be accurately evaluated and maxillary and mandibular structural changes can be directly compared with same 3D vectors.

Impact of Steam Autoclaving on the Mechanical Properties of 3D-Printed Resins Used for Insertion Guides in Orthodontics and Implant Dentistry

Guided implant placement has been shown to be more accurate than free-handed insertion. Still, implant position deviations occur and could possibly pose risks. Thus, there is a quest to identify factors that might impair the accuracy of implantation protocols using templates. This study aimed to investigate the influence of autoclaving cycles (cycle 1: 121 °C, 1 bar, 20.5 min; cycle 2: 134 °C, 2 bar, 5.5 min) on the Vickers hardness and flexural modulus of five different materials used for 3D-printed insertion guides. The specimens were subjected to Vickers hardness tests, showing significant changes in the Vickers hardness for two and three materials out of five for cycle 1 and 2, respectively. The results of the three-point bending tests (n = 15 specimens per material) showed decreasing flexural moduli after autoclaving. However, changes were significant only for one material, which presented a significant decrease in the flexural modulus after cycle 2. No significant changes were detected after cycle 1. In conclusion, our findings show that autoclaving can alter the mechanical properties of the templates to some extent, especially with cycle 2. Whether these modifications are associated with dimensional changes of the templates and reduced accuracy of the implantation protocols remains to be investigated.

The effects of micro-osteoperforation on upper first molar root resorption and bone density after distalization by miniscrew-supported Fast Back appliance in adults: A CBCT randomized controlled trial

OBJECTIVE

To evaluate, primary the effects of Micro-osteoperforation (MOP) on orthodontically induced inflammatory root resorption (OIIRR) of maxillary first molars, and secondary, the density of surrounding alveolar bone during distalization phase with Fast Back distalizer.

MATERIALS AND METHODS

Female patients between 16-20 years of age (University of Mansoura), meeting the criteria, were included between March to September 2019. They were randomly, and equally allocated into control and MOP groups. Both of them underwent distalization with Fast Back distalizer. 3MOPs were applied in the intervention group, distal to the first molars using a 3D printed guide. CBCT images were obtained before and after distalization. Apical root resorption maxillary first molars' roots, and alveolar bone density surrounding them were evaluated using independent-samples t-test. Time of distalization phase was assessed using Mann-Whitney U test. Correlation and partial correlation tests were done between resorption of roots, bone density, and time.

RESULTS

Screening of 50 patients, and exclusion for 30 of them were done. Only 20 subjects underwent the trial to the end. In MOP group, OIIRR of mesiobuccal roots significantly increased (MD=-0.2 (-0.34 to -0.01), P<0.05), and significantly decreased for disto-buccal roots (MD=0.6 (0.45 to 0.72), P<0.001). The second and third layers of bone density decreased significantly in MOP group (MD=116.7 (50.8 to 182.5), MD=560.4 (327.9 to 792.7) respectively, P<0.001). Time for distalization phase was significantly reduced in MOP group (P<0.001).

CONCLUSIONS

MOP decreased OIIRR for nearby distobuccal roots by reduction in surrounding density of bone, and increased OIIRR for the far mesiobuccal roots.

Maxillary protraction and vertical control utilizing skeletal anchorage for midfacial-maxillary deficiency

INTRODUCTION

The efficacy and efficiency of early treatment of skeletal Class III patients with facemask therapy are well-documented; however, very few cases for adolescents or adults were reported.

OBJECTIVE

The aim of this case report was to demonstrate skeletal and dental correction of a post-pubertal-growth-spurt patient whose malocclusion consisted of a skeletal Class III with slight transverse deficiency, a high mandibular plane angle, and a retrusive maxillary complex.

CASE REPORT

A 13-year-5-months old Hispanic female was diagnosed as a retrognathic maxilla and mandible, a high mandibular plane angle, open bite pattern, a bilateral Angle Class I molar relationship with an anterior crossbite on the maxillary lateral incisors. A TAD-supported Haas rapid palatal expander was utilized for maxillary protraction combined with a facemask, vertical control, and maxillary molar distalization with fixed appliance.

RESULTS

The total treatment time was 26 months. An improved facial profile with maxillary lip support and more prominent cheeks was established. Adequate vertical control prevented a change in the mandibular plane angle even though facemask treatment can increase the vertical dimension. After the 18-month retention, excellent stability of the treatment results was shown.

CONCLUSION

With skeletal anchorage and facemask treatment, orthodontists have the ability of expanding and protracting the maxilla without tipping maxillary molars buccally and without the risk of unfavorable periodontal consequences. A TAD-supported Haas rapid palatal expander allowed to control the vertical dimension and distalize molars, while minimizing undesired consequences.

Determination of sex dimorphisms of the thickness of the hard palate in adolescence using computed tomography: Pilot study

BACKGROUND

In addition to traditional craniometric techniques, computer craniometry has been used in recent decades, including stereometric methods, which make it possible to determine the microanatomical spatial relationships and dimensional features of various structures of the skull, in particular the thickness of the inert palate of the maxilla.

AIM

Determination of the gender-specific variability of the thickness of the bony palate at the age of 18-20 years using CT.

MATERIAL AND METHODS

The material of the pilot study were 40 computed tomograms of young males and females aged 18-20 years. The method of computer craniometry was used to measure the thickness of the bony palate in sagittal projection taking into account the gender. A graphic raster map was created to identify the palatal areas, then analyze their thickness and determine the safe zones for the mini dental implants.

RESULTS

In young males and females (18-20 years) the thickness of the bony palate decreases at different levels from front to back and from the median suture to the alveolar process. The greatest thickness of the bony palate corresponds to its anterior third and reliably predominates in young males at all levels compared to young females. In the middle and posterior third palate, the averages do not show gender differences and their variation is insignificant.

CONCLUSIONS

The greatest thickness of the bony palate can be used as the most favorable zone for the fixation of orthodontic mini dental implants. The variability in the thickness of the bony palate should be considered when selecting the most optimal zones and depth of mini-implant placement.

Treatment of maxillary transversal deficiency by using a mini-implant-borne rapid maxillary expander and aligners in combination

Bone-borne rapid maxillary expansion distraction devices are used to achieve a more skeletal expansion and to avoid dental side effects of conventional expanders such as tipping of anchorage teeth. In this article, we report the use of a prefabricated expander fixed on 2 mini-implants in the anterior palate. This allows for the insertion of the mini-implants and the expander to occur without the need for an impression or any laboratory procedures. Especially when aligners are going to be used, the use of a mini-implant-borne expander seems to be reasonable because the expander can be left in place as a skeletal retainer during the aligner finishing.

Evaluation of mandibular buccal shelf characteristics in the Colombian population: A cone-beam computed tomography study

Objective

To evaluate the mandibular buccal shelf (MBS) in terms of the angulation and bone depth and thickness according to sex, age, and sagittal and vertical skeletal patterns in a Colombian population using cone-beam computed tomography (CBCT). Accordingly, the optimal site for miniscrew insertion in this area was determined.

Methods

This descriptive, retrospective study included 64 hemi-arches of 34 patients. On CBCT images, the angulation, buccal bone depth (4 and 6 mm from the cementoenamel junction [CEJ] of MBS), and buccal bone thickness (6 and 11 mm from the CEJ of MBS) were measured at the mesial and distal roots of the mandibular first and second molars.

Results

There were no statistically significant differences in the angulation, depth, and thickness of MBS between male and female patients. The values for the bone around the distal root of the mandibular second molar were significantly greater than the other values. The osseous characteristics were significantly better in participants aged 16–24 years. Class III patients exhibited the best osseous characteristics, with the bone depth at 6 mm being significantly different from that in Class I and Class II patients. Although values tended to be greater in patients with low angles, the difference was not statistically significant.

Conclusions

MBS provides an optimal bone surface for miniscrew insertion, with better osseous characteristics at the distal root of the mandibular second molar, 4 mm from CEJ. Adolescent patients, Class III patients, and patients with a low angle exhibit the most favorable osseous characteristics in the MBS area.

CBCT and CAD-CAM technology to design a minimally invasive maxillary expander

Background

A large number of articles in recent years studying the effects of non-surgically assisted tooth- versus bone-borne maxillary expanders in growing patients have found no significant differences in mid-palatal suture disjunction or even dentoalveolar changes. This suggests the need for new criteria and better use of current technology to make more effective devices and enhance the benefits of conventional treatments. This article describes a titanium grade V computer-aided design/computer-aided manufacturing (CAD/CAM) maxillary expander supported by two miniscrews, along with a 3D printed surgical guide.

Methods

The first step was to obtain a digitized model of the patient’s upper maxilla. To simplify the process and ensure the placement of the device in a high-quality bone area, the patients’ digital dental cast was superimposed with a cone beam computed tomography (CBCT) scan. Improved resistance to expansion forces was secured through the use of 2 mm-wide miniscrews, long enough for bicortical anchorage. Placement site and direction were assessed individually in order to achieve primary stability. We chose a site between the second premolars and first molars, while the inclination followed the natural contour of the palate vault. A 3D-printed, polyamide surgical guide was designed to ensure the correct placement of the device with a manual straight driver.

Results

Favorable clinical results were presented with 3D images. We confirmed a mid-palatal suture parallel separation of 3.63 mm, along with a higher palatal volume, as well as increased intercanine and intermolar distance. Segmentation of the facial soft tissue showed an expansion of nasal airways and changes in nasal morphology.

Conclusions

Digital models, CBCT and CAD/CAM technology, are essential to accomplish the goals proposed in this article. Further studies are necessary to establish safer miniscrew placement sites and insertion angles so as to achieve greater in-treatment stability. Both the clinician and the patient can benefit from the use of current technology, creating new devices and updating traditional orthodontic procedures.

Suitability of virtual plaster models superimposed with the lateral cephalogram for guided paramedian orthodontic mini-implant placement with regard to the bone support

PURPOSE

The purpose of this study was twofold: first, to evaluate the precision of guided orthodontic mini-implant (OMI) placement planned on virtual superimposition of plaster models and lateral cephalograms with regard to the bone support and, second, to investigate the effects of silicone guide extension.

METHODS

A total of 40 OMIs were placed in the paramedian area of the anterior palates of 20 cadaver heads. Digitalized models and the corresponding lateral cephalograms were superimposed for planning the OMI positions, and tooth-supported (TS) and soft-tissue-supported (STS) templates were manufactured. Thereafter, postoperative cone beam computed tomography (CBCT) was performed, and the straight (A) and right-angle distance (B) from the implant tip to the nasal floor, the distance from the implant shoulder to the hard palate (C) and the angle (α) between the implant and palate plane with the preoperative (T0) and postoperative (T1) positions were measured.

RESULTS

The postoperative distances A, B, and C were less than the planned implant positions. However, significant difference between T0 and T1 was only noted in terms of distance A using the TS templates (T0: 4.7 ± 2.3 mm, T1: 3.0 ± 2.3 mm; p = 0.008) and distance B using the STS template (T0: 3.1 ± 3.5 mm, T1: 2.3 ± 3.2 mm; p = 0.041). There were no significant differences in all average deviations (∆ Ceph/CBCT) between the two templates.

CONCLUSIONS

Guided OMI placement planned by virtual superimposition of digitized models and the corresponding lateral cephalogram is fundamentally feasible. However, the position closer to the nasal floor needs critical assessment for correct implantation. The silicone template expansion seems to have only a minor effect on transfer accuracy.

Anatomical assessment by cone beam computed tomography with the use of lateral cephalograms to analyse the vertical bone height of the anterior palate for orthodontic mini-implants

OBJECTIVE

Lateral cephalograms (LC) should be usable to evaluate the vertical bone height of the anterior maxilla for planning the placement of orthodontic mini-implants (OMI). The purpose of this study is to determine the usability of LC for examining the real vertical dimension of the anterior palate.

SETTING AND SAMPLE POPULATION

Lateral cephalograms and corresponding cone beam computed tomography (CBCT) scans were employed for examining 30 fresh cadaver heads.

MATERIALS & METHODS

The minimum (distance A) and maximum (distance B) vertical palatal bone heights on LCs at the level of first premolars were measured, whereas the corresponding measurements were taken via CBCTs on the median, and 2-, 4- and 6-mm paramedian planes. Additionally, the overall minimum vertical palatal height on CBCT was recorded.

RESULTS

Distance A and B on LC were about 8.3 ± 2.5 mm and 9.9 ± 2.5 mm, respectively. The median palatal height on CBCT was significantly higher than both measurements on LC (P < .01). Furthermore, the bone supply on the paramedian planes was similar or higher on CBCT compared to Distance A and similar or less compared to Distance B. The strongest correlation at the level of the premolars was found in the comparison of the maximum vertical palatal height via LC with the vertical palatal height on the median plane via CBCT (r = .84, 95% CI: 0.69-0.92, P < .001).

CONCLUSIONS

In order to make the best possible use of the vertical bone supply of the anterior palate and to avoid injuries to the nasal floor, Distance A should be taken into account for planning paramedian OMI placements and distance B for median OMI insertion.

The ideal insertion angle after immediate loading in Jeil, Storm, and Thunder miniscrews: A 3D-FEM study

OBJECTIVE

The miniscrew is effectively used to provide additional anchorage for orthodontic purposes. The aim of this study was to identify an optimal insertion angle for Jeil, Storm, and Thunder miniscrews on stress distribution at the bone miniscrew interface.

MATERIALS AND METHODS

To perform 3-dimensional finite element model analysis, a 3-dimensional model with a bone block was constructed with type D2 of bone quality, and with miniscrews of Storm, Thunder, Jeil, with the diameter of 2, 1.5. 1.6mm and length 15.9, 12.4, 14.4mm respectively. The miniscrews were inserted at 15° 30°, 45°, 60°, 75° and 90° to the bone surface. A simulated horizontal orthodontic force of 200 gram was applied to the centre of the miniscrews head in all models, and stress distribution and its magnitude were evaluated with a 3-dimensional finite element analysis program.

RESULTS

In the cancellous bone, minimum stress was found at placement angles of 90° for Jeil and Storm, which was 0.37 and 0.39MPa respectively, and 15° for Thunder, which was 0.85MPa. The maximum von Mises stresses in the cancellous bone for Jeil was at 60°, which was 0.92MPa, and for Thunder at 90°, which was 1.3MPa.

CONCLUSION

Each miniscrew has an ideal insertion angle, optimal insertion positions were found within 90° for Jeil and for Storm but 15° for Thunder. Clinical significance 3-dimensional finite element analysis confirmed that each miniscrew has an ideal insertion angle according to its characteristics.

Assessment of the cortical bone thickness by CT-scan and its association with orthodontic implant position in a young adult Eastern Mediterranean population: A cross sectional study

OBJECTIVE

This study was conducted to assess cortical bone thickness in the alveolar process of maxilla and mandible and to investigate its association with different orthodontic implant positions in Eastern Mediterranean young adults.

MATERIALS AND METHODS

Computed tomography images of 50 patients aged between 18-35 years were included. Buccal, palatal and lingual cortical bone thicknesses were measured at 2, 4, 6, and 8mm from cemento-enamel junction starting from the mesial side of the second molar to the contralateral side. Pearson correlation was used to assess the association between cortical bone thickness and proposed orthodontic implant positions at all inter-radicular sites (p<0.05).

RESULTS

The highest value of buccal cortical bone thickness was found mesial to the second molar in the maxilla and mandible for both genders. The value of palatal cortical bone thickness was found to be at the highest rate mesial to canine and first premolar in males and females respectively. On the other hand, the highest value of lingual cortical bone thickness was recorded to be mesial to the first molar in both genders. In addition to that, the buccal cortical bone thickness was significantly higher than palatal at the area mesial to the second molar at all four levels from the cemento-enamel junction. A significant correlation was found between cortical bone thickness and 2, 4, 6, and 8mm orthodontic implant levels in all inter-radicular sites. The values of correlation coefficients ranged from 0.280 to 0.674 in the maxillary arch and from 0.266 to 0.605 in the mandibular arch.

CONCLUSIONS

From this study, we can conclude that as the position of the orthodontic implant moved more posteriorly and apically more cortical bone thickness was expected to be found in both jaws. A significant correlation was found between cortical bone thickness and the site of the orthodontic implant. Cortical bone thickness and its relationship with implant position should be taken into consideration when attempts are made to insert the orthodontic implant.