Infrazygomatic Crest Research Articles

Evaluation of Two Mini-implant Lengths in the Infrazygomatic Crest Region: A Randomized Clinical Trial.

Temporary anchorage devices (TADs) have revolutionized fixed orthodontic appliance treatment through anchorage controlling in the clinic and play an essential role in resolving many complex cases. Due to the limited space, there is a risk of injury to the roots while using interradicular microimplants. Therefore, the infrazygomatic crest (IZC) area can be an alternative mini-implant insertion site in the maxillary arch. The aim of the study was to evaluate the primary stability, pain perception, sinus penetration, late stability, and failure rate with two mini-implant lengths in the IZC area. Forty-eight mini-implants (Tusk Dental Co., Ltd., Canada) with two different lengths (length/diameter: 12/2 and 14/2 mm) were grouped by length (24 per group) and inserted bilaterally into the IZC area of 24 patients. The data were statistically analyzed, considering a significance level of p < 0.05. Sinus penetration prevalence did not differ significantly between 12-mm (54.2%) and 14-mm (62.5%) mini-implants (p > 0.05). Primary stability was significantly higher with the 14-mm mini-implants (p < 0.05). The failure rate did not differ significantly between the 12-mm (20.8%) and 14-mm (16.7%) mini-implants (p > 0.05). While the failure rate was similar between 12- and 14-mm mini-implants, the 14-mm mini-implants were more likely to damage adjacent structures. Therefore, shorter mini-implants should be preferred over longer mini-implants for most cases requiring IZC TADs. ClinicalTrials.gov identifier: NCT06293872.

Evaluation Of Bone Thickness At Different Anatomical Sites In Infrazygomatic Crest For Miniscrew Insertion In Skeletal Class II Patients – A CBCT Study

AIM: To assess infrazygomatic crest bone thickness at different anatomical sites at a distance of 5mm, 7mm, 9mm and 11mm apical to cementoenamel junction, 70 degree to occlusal plane in skeletal class II patients using cone beam computed tomography (CBCT). Materials and Methods: The sample consists of cone beam computed tomography images of 23 class II subjects were evaluated. Infrazygomatic crest bone thickness was evaluated at the six horizontal regions (i) interdental area between maxillary second premolar (PM2) and first molar(M1) (ii) Mesiobuccal root of maxillary first molar (MB root of M1) (iii) Distobuccal root of maxillary first molar(DB root of M1) (iv) interdental area between maxillary first molar(M1) and second molar(M2) (v) Mesiobuccal root of maxillary second molar(MB root of M2) (vi) Distobuccal root of maxillary second molar (DB root of M2) at a vertical distance of 5mm,7mm,9mm and 11mm apical to cementoenamel junction, 70 degree to occlusal plane. Results: The buccal bone thickness increase from mesial surface of maxillary first molar to mesial surface of maxillary second molar from cement enamel junction at the level of 11mm, 70 degree to the occlusal plane. The bone thickness decreases at the second molar level. Conclusion: The safe site for insertion of miniscrews in the infrazygomatic crest were the interdental region between the maxillary first and second molars at the heights of 11 mm from cementoenamel junction and 70 degree to the occlusal plane

An in vitro study of a combined patient-specific device for safe and accurate insertion of infrazygomatic crest miniscrews.

To develop and assess the efficacy of a novel combined patient-specific device (CPSD) for the accurate and safe insertion of infrazygomatic crest miniscrews in orthodontic procedures. Twenty-eight miniscrews were placed in the infrazygomatic crest region of 28 cadaver maxillae using the direct manual method (n = 14) or the CPSD (n = 14) based on preset trajectories. The CPSD, designed based on the integration model, included a positioning guide, an insertion guide, and a depth-limiting groove. Deviations in the insertion site, tip location, insertion angle, and biting depth between the preset and real insertion trajectories were calculated to evaluate the accuracy of miniscrew insertion. Classification frequencies of root proximity, sinus penetration depth, and biting depth of the miniscrew after insertion were also calculated to evaluate the safety of miniscrew insertion. Regarding evaluation of accuracy, significant differences were observed in the deviation values of the insertion site, tip location, insertion angle, and biting depth between the CPSD and freehand groups (P = .001, P < .001, P < .001, P = .039, respectively). Regarding evaluation of safety, a significant difference was observed in the classification frequencies of root proximity between the two groups (P = .016). Compared with manual insertion, CPSD could be a preferred method for safe and accurate insertion of infrazygomatic crest miniscrews for orthodontists.

The implementation of miniscrews in the infrazygomatic crest and pyramidal process of the maxilla

The article presents an analysis of the features of the use of orthodontic implants in the zygomaticoalveolar ridge and pyramidal process of the palatine bone during distalization of the lateral group of teeth of the upper jaw. The development of a treatment plan and the course of treatment are illustrated by a clinical example of treating a patient in the “Russian University of Medicine” orthodontic clinic, where distalization of the lateral groups of teeth on the upper jaw was performed by 2 mm on the right and 3 mm on the left with support on orthodontic implants installed in the zygomaticoalveolar ridge and pyramidal process of the palatine bone. An assessment of the effectiveness of distalization, bone volume, and gum condition was carried out, differences in the biomechanics of distalization with support on implants installed retromolarly and in the zygomaticoalveolar ridge were noted. The advantages of using orthodontic implants of the intrazygomatic ridge in patients with the dentoalveolar form of distal occlusion were revealed.

To evaluate the cortical bone thickness for ideal placement of infrazygomatic crest (IZC) and mandibular buccal shelf (MCS) bone screws in patients with different facial pattern using cone-beam computed tomography (CBCT)

This study aimed to measure the cortical bone thickness at different anatomical sites of InfraZygomatic Crest and Mandibular Buccal Shelf region for the ideal placement of IZC and MBS screws respectively in patients with different facial patterns using CBCT.Total participants were divided into 3 groups- GROUP A: horizontal growth pattern (FMA &amp;#60;22°); GROUP B: average growth pattern (FMA 22°-28°); GROUP C: vertical growth pattern(FMA &amp;#62;28°). Sixty CBCT images were taken into consideration. They were converted into standard DICOM format. Bone thickness were measured in the InfraZygomatic Crest (IZC) of the maxilla and in the Mandibular Buccal Shelf (MBS) region of the mandible using the Kodak CareStream CS 9300 Software.The results indicate that there was a highly statistical significant difference seen in the overall cortical bone thickness of IZC and MBS at various anatomical sites. The highest mean thickness was found to be at the MB70◦ maxillary 1st molar and distal root of the mandibular 1st molar. There was no difference in the bone thickness at the IZC region and at the MBS region seen between the horizontal and vertical facial patterns whereas the average facial patterns show the highest mean thickness but was not statistically significantThe study conducted on the Indian population yielded results demonstrating the possibly appropriate position for the IZC bonescrews and MBS bonescrews suggested that placing the IZC bonescrews at the mesiobuccal root of the maxillary 1st molar at an angulation of 70◦ and the MBS bonescrews at the distal root of the mandibular 1st molar at 11mm from the cementoenamel junction irrespective of the facial patterns could provide positive results.

Correcting a skeletal ClassII malocclusion with full maxillary dental arch distalisation using Infra-zygomatic crest (IZC) bone screw: A case report

Managing a correction of Skeletal Class II malocclusion has remained a challenge to a experience clinician solving this challenge involves surgical and non -surgical methods. The patient centered approach towards non-surgical correction which involves 3-Dimenional innovative tooth movement.Recently the clinician have tried to distalize the entire maxillary dentition by using Bone anchored supportive system which was previously tooth anchored. Bone anchored system nullifies the reciprocal component of force and hence no unwanted dental movements. Use of IZC is one such kind which helps in correcting skeletal Class II malocclusion with distalizing maxillary arch.

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

BackgroundThe 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.MethodsNinety 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.ResultsIn 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).ConclusionsThe 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.

Assessment of Bone Thickness at the Infra Zygomatic Crest Region for Various Orthodontic Miniscrew Implant (OMSI) Insertion Angles: A Cone-Beam Computed Tomographic Study.

To evaluate the infrazygomatic crest (IZC) bone and develop guidelines for the optimum placement of orthodontic miniscrew implants (OMSIs) along the distobuccal root of the permanent maxillary first molar. Bone thickness of the IZC region of 50 young adults (25 males and 25 females) aged 18-30 years were evaluated using cone-beam computed tomography images. The infrazygomatic bone thickness along the distobuccal root of the permanent maxillary first molar was assessed at various insertion angles (40° to 75° i.r.t the maxillary occlusal plane) with an increment of 5°. Student's t-test was used to compare the IZC bone thickness and height at the orthodontic miniscrew insertion site for males and females on the right and left sides. The bone thickness of the IZC region above the distobuccal root of the permanent maxillary first molar was estimated between 4.39±0.25 mm and 9.03±0.45 mm for insertion angles from 40° to 75° to the maxillary occlusal plane. The corresponding OMSI insertion heights were 17.71±0.61 mm to 13.69±0.75 mm, respectively, above the maxillary occlusal plane. There were statistically significant gender and side-wise variations in bone thickness at the IZC area and insertion height. The safe position for OMSI placement at the IZC was 13.69-16 mm from the maxillary occlusal plane with an insertion angle between 55° and 75°. These parameters provide the optimum placement of OMSIs along the distobuccal root of the permanent maxillary first molar.

Evaluation of bone thickness at infra-zygomatic crest region compared with cervical vertebrae maturation index.

Orthodontists should know variation in thickness of infrazygomatic crest region according to maturation status of patients. Therefore, it is of interest to evaluate the thickness of bone at infrazygomatic crest region and to correlate the thickness of bone with cervical vertebrae maturation index (CVMI) incorporating CBCT.A retrospective analysis of 120 patients' CBCT scans60 of them male and 60 female-was carried out. The thickness of the bone was determined at five locations. Using CBCT, the cervical vertebral maturation was created and the Hassel-Farmann index was used for analysis. A lone researcher conducted all of the measurements. Bone thickness of infrazygomatic arch at all five locations was found to increase as the maturation stage progressed from initiation stage to maturation stage. Then there was decrease in the bone thickness in completion stages compared to maturation stage. The thickness of bone at infrazygomatic arch is significantly correlated with CVM stages as determined by CBCT.

Image fusion-based low-dose CBCT enhancement method for visualizing miniscrew insertion in the infrazygomatic crest

Digital dental technology covers oral cone-beam computed tomography (CBCT) image processing and low-dose CBCT dental applications. A low-dose CBCT image enhancement method based on image fusion is proposed to address the need for subzygomatic small screw insertion. Specifically, firstly, a sharpening correction module is proposed, where the CBCT image is sharpened to compensate for the loss of details in the underexposed/over-exposed region. Secondly, a visibility restoration module based on type II fuzzy sets is designed, and a contrast enhancement module using curve transformation is designed. In addition to this, we propose a perceptual fusion module that fuses visibility and contrast of oral CBCT images. As a result, the problems of overexposure/underexposure, low visibility, and low contrast that occur in oral CBCT images can be effectively addressed with consistent interpretability. The proposed algorithm was analyzed in comparison experiments with a variety of algorithms, as well as ablation experiments. After analysis, compared with advanced enhancement algorithms, this algorithm achieved excellent results in low-dose CBCT enhancement and effective observation of subzygomatic small screw implantation. Compared with the best performing method, the evaluation metric is 0.07–2 higher on both datasets. The project can be found at: https://github.com/sunpeipei2024/low-dose-CBCT.

Failure rate of infra-zygomatic crest (IZC) bone screws in orthodontics: A Systematic review

The aim of this review is to provide a precise estimation of infra-zygomatic crest (IZC) bone screw failure rate during orthodontic treatment. Data were obtained using the Cochrane Central Register of Controlled Trails (central), PUBMED, EMBASE, google scholar, OVID, Wiley library till 1 January 2022. The titles and abstract of the electronic search were screened and evaluated by two observers according to the inclusion and exclusion criteria. This review was enrolled in PROSPERO (registration ID number CRD42020206610). There were 1725 records identified through electronic and 1 additional record identified through manual search. After 377 duplicate removal, 1349 studies were screened on the base of title and abstract the final sample included 9 studies that meet the primary inclusion criteria were selected. Each study was assessed using the evaluation method described in the Cochrane handbook for systematic reviews. All studier collectively included of the 1238 IZC miniscrews. Included studies ranged from 20 to 772 IZC miniscrews and the average number was approximate 137 IZC miniscrews per study. The diameter of inserted IZC miniscrews ranged from 1.2 to 2.3 mm and length ranged from 6 to 17 mm. The recorded failure rate ranged from 0% to 47.2%, and the average failure rate for IZC miniscrew was 9.45% (with 95% CI [58.91; 93.82]).IZC miniscrew has low failure rate which suggest that IZC miniscrew are clinically reliable. Miniscrew are a stable anchorage for orthodontic tooth movement and zygomatic buttress of maxilla is suitable region for skeletal anchorage device placement.

Comparison of different maxillary advancement protocols in patients with unilateral cleft lip and palate: a finite element analysis.

The aim of this study was to evaluate the stress distributions and possible amount of movement in the maxillofacial region resulting from different maxillary advancement protocols in patients with unilateral cleft lip and palate. A unilateral cleft lip and palate model (CLP model) with Goslon score 4 was created for finite element analysis. Three different protocols were compared: Group 1: usage of a face mask with elastics placed at a 30? angle to the occlusal plane over a conventional acrylic plate; Group 2: usage of a face mask with elastics placed at a 30? angle to the occlusal plane over miniplates placed in the infrazygomatic crest region; Group 3: usage of elastic from the menton plate placed in the mandible to the infrazygomatic plates in the maxilla. Dental effects were greater in the maxillary protraction protocol with a face mask over a conventional acrylic plate (Von Misses Stress Values; Group 1?=?cleft side:0.076, non-cleft side:0.077; Group 2?=?cleft side:0.004, non-cleft side: 0.003; Group 3?=?cleft side:0.0025; non-cleft side:0.0015), whereas skeletal effects were greater in maxillary protraction protocols with face mask using skeletal anchorage (Von Misses Stress Values; Group 1:0.008; Group 2:0.02; Group 3:0.0025). The maximum amount of counterclockwise rotation of the maxilla as a result of protraction was observed in traditional acrylic plate face mask protocol, and the minimum amount was observed by using elastics between infrazygomatic plates and menton plate. In individuals with unilateral cleft lip and palate with Goslon score 4, it was observed that the skeletally anchored face mask caused more skeletal impact and displacement than both the traditional acrylic plate face mask model and the pure skeletally supported maxillary protraction model. When planning maxillary protraction treatment in patients with cleft lip and palate, it should be considered that more movement in the sagittal plane might be expected on the cleft side than the non-cleft side, and miniplate and screws on the cleft side are exposed to more stress when using infrazygomatic plates as skeletal anchorage.

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

To determine the optimal placement of miniscrews, this study compared adult male and female patients in terms of cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest region. The cone beam computed tomography imaging data of 200 patients (20-30 years old; 100 males and 100 females) were collected. The right maxillary posterior teeth in the sagittal plane were divided into six levels from proximal to distal, and three measurement sites were positioned at vertical distances of 8, 10, and 12 mm from the cementum. Cortical bone density, cortical bone thickness, and available bone width were measured in 18 measurement sites in the infrazygomatic crest and analyzed statistically. The highest cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest in adult male and female patients were at the level of the interradicular space between the maxillary second premolar and maxillary first molar. The bone cortical density and thickness increased with vertical height, whereas the available bone width decreased with increasing vertical height. Differences were observed in cortical bone density, cortical bone thickness, and available bone width between adult male and female patients. The optimal implantation sites of the micro-implant anchorages in the infrazygomatic crest were at the level of the interradicular space between the maxillary second premolar and the maxillary first molar, and the vertical height of the optimal implantation site in males was appropriately higher than that in females.

Analysis of the changes in components of smile after maxillary arch distalization using infra-zygomatic crest (IZC) screws – A cephalometric and photographic study

Objectives: The purpose of this study was to analyze the effects of infra-zygomatic crest (IZC) screws on smile components after maxillary arch distalization. Materials and Methods: The study was conducted on 20 subjects (11 boys and 9 girls) between 19 and 30 years. It was a time-bound study where screening of patients was done based on the inclusion and exclusion criteria for a year. Before placement of orthodontic bone screws (IZC), pre-treatment (T0) photographs, and cephalograms were taken where photographs were analyzed using Makhter’s software. After 6–8 months, post-distalization treatment (T1) photographs and cephalograms were taken and evaluated. Results: Descriptive statistics were used to obtain the mean and standard deviation for continuous data. Paired t-test was performed to analyze the changes in pre- and post-distalization. The categorical data were calculated using the McNemar test. Differences were considered significant if P &lt; 0.05. Inner commissure right and left, smile arc, posterior maxillary dentition visible - left (PMDVL), upper incisal visibility, and gingival showed statistical significance. Conclusion: Maxillary arch distalization using IZC screws was associated with changes in horizontal smile components but mainly in vertical components, reducing the gummy smile, and making the smile esthetically pleasing.

Biomechanical analysis of total arch maxillary distalization using infrazygomatic crest miniscrews: a finite element analysis study

AimTo evaluate the maxillary incisors and canine’s immediate movement tendency using three different power arms (PA) height levels during total arch maxillary distalization supported on infrazygomatic crest (IZC) miniscrews according to finite element analysis (FEA).MethodsThree finite element models of the maxilla were developed based on CBCT imaging of a teenage male patient presenting a Class II Division 1 malocclusion in the early permanent dentition. Maxillary complex, periodontium, orthodontic accessories, IZC miniscrews and an orthodontic wire were digitally created. The PAs were placed between canines and lateral incisors and projected at 4, 7, and 10 mm height distances. After that, distalization forces were simulated between PA and IZC miniscrews.ResultsThe anterior teeth deformation produced in the FEA models was assessed according to a Von Mises equivalent. The stress was measured, revealing tendencies of initial maxillary teeth movement. No differences were found between the right and left sides. However, there was a significant difference among models in the under-stress areas, especially the apical and cervical root areas of the maxillary anterior teeth. More significant extrusion and lingual tipping of incisors were observed with the 4 mm power arm compared to the 7 mm and 10 mm ones. The 10 mm power arm did not show any tendency for extrusion of maxillary central incisors but a tendency for buccal tipping and intrusion of lateral incisors.ConclusionThe maxillary incisors and canines have different immediate movement tendencies according to the height of the anterior point of the en-masse distalization force application. Based on the PA height increase, a change from lingual to buccal tipping and less extrusion tendency was observed for the incisors, while the lingual tipping and extrusion trend for canines increased.

Retrospective comparison of two different miniscrew-supported molar distalization methods applied in the buccal and palatal regions

BackgroundTo compare dentofacial effects of distalization with miniscrew-supported pendulum and infrazygomatic crest miniscrews. MethodsThe study included 36 patients whose lateral cephalometric radiographs were obtained before (T0) and after (T1) distalization. Patients were divided into two groups according to the treatment methods: 1) distalization with miniscrew-supported pendulum (MSP) (n = 19; 14 girls and 5 boys; mean age 16.9 ± 1.46 years) and 2) distalization with infrazygomatic crest (IZC) miniscrews (n = 17; 8 girls and 9 boys; mean age 17.0 ± 1.68 years). Dental, skeletal and soft tissue measurements were performed on lateral cephalograms taken from individuals. ResultsA significant molar distalization was achieved both in the MSP group (3.52 ± 0.76 mm at 8.71 ± 2.02 months) and the IZC group (3.5 ± 0.74 mm at 9.7 ± 2.5 months) (P < 0.001 for both). Premolar distalization was significantly lower in the MSP group (1.73 ± 1.09 mm) than in the IZC group (2.81 ± 0.79 mm) (P < 0.01). Significant molar tipping was observed in both groups (P < 0.001), while no significant difference was found between the groups (P > 0.05). Retrusion of maxillary incisors were significantly higher in the IZC group (2.75 mm) than in the MSP group (0.98 mm) (P < 0.01). A significant difference was found between the two groups with regard to the changes in overjet and overbite (P < 0.05). ConclusionsBoth distalization methods were found to be effective in achieving a Class I molar relationship in patients with Class II malocclusion.

Comparing the Efficiency of Infrazygomatic Crest (IZC) Screws and Conventional Method for Anterior Retraction in Patients Undergoing Fixed Orthodontic Treatment for Class 2 Malocclusion: A Prospective Clinical Study.

Introduction In orthodontic treatment for class 2 malocclusion, conventional approaches involve extracting the upper first premolars and using methods like en masse retraction and extra-oral or intra-oral distalization. However, these often result in unintended forces and adverse effects. Contemporary techniques, such as maxillary arch distalization with mini-implants like infrazygomatic crest (IZC) implants, offer superior outcomes. IZC implants provide a safe, flexible, and effective site for implant placement, achieving a remarkable 93.7% success rate. Power arms enable precise control, allowing orthodontists to apply controlled forces for optimal tooth movement. This study aims to compare cephalometric parameters pre and post treatment using IZC/buccal shelf (BS) screws and conventional retraction, assessing the efficiency of IZC screws in maintaining arch length during teeth retraction. Methods In a split-mouth study at Yenepoya Dental College, 40 orthodontic patients aged 18-35 were divided into control (premolar extraction, anterior retraction) and study (third molar removal, IZC screw distalization) groups. The control group used a nitinol spring/E chain for retraction, while the study group employed IZC screw-assisted en masse distalization. Regular reviews and adjustments occurred, with radiographs and study models assessed after six months for cephalometric parameters and arch length. Results A significant difference was found in U1-SN (degree), L1-Apog (in mm), L1-NB (degree), and L1-NB (in mm) of pretreatment records, whereas all other measurements showed statistically similar values between conventional and IZC groups. Improvement was higher with the conventional group when compared with IZC groups in these measurements due to the extraction of the first premolars rather than third molar extraction and distalization. However, the IZC group also showed statistically significant improvement in cephalometric parameters such as U1-SN (degree), L1-Apog (in mm), L1-NB (degree), and L1-NB (in mm). Conclusion The statistical analysis of radiographic and cast measurements in both the maxilla and mandible demonstrated a significant efficiency of IZC screws in teeth retraction while preserving arch length compared to conventional methods. Nevertheless, to strengthen the findings of our study, additional clinical investigations on IZC screws are warranted.

An evaluation of bone depth at different three-dimensional paths in infrazygomatic crest region for miniscrew insertion: A cone beam computed tomography study

ObjectiveTo investigate the difference and distribution of bone depth at different three-dimensional simulated paths to help optimize the insertion path for miniscrew placement in the infrazygomatic crest. MethodsCone beam computed tomography scans of 80 adults (38 males and 42 females; mean age, 27.0 years) were assessed. For each subject, bone depth of 81 simulated insertion paths at different insertion points and three-dimensional angulations was measured in 160 infrazygomatic crests; the differences were evaluated using the adjusted Friedman test. The bone deficiency ratio for each path was calculated. Distributions of measurements were analyzed and reported as specially designed colormaps. ResultsBone depth increased, and bone deficiency ratio reduced mesially to distally (P < 0.001), apically to coronally (P < 0.01), and at a greater gingival and distal inclination (P < 0.05). The maximum bone depth (10.72 mm) was observed 13 mm above the maxillary occlusal plane in the mesiobuccal root of the maxillary second molar. The minimum bone depth (3.4 mm) was observed 17 mm above the maxillary occlusal plane in the distobuccal root of the maxillary first molar. No bone deficiency was detected at the paths of 13 mm above the maxillary occlusal plane at a gingival inclination of 70° and distal inclination of 30° in the mesiobuccal root of the maxillary second molar. The highest bone deficiency ratio is present 17 mm above the maxillary occlusal plane at a gingival inclination of 60° and a distal inclination of 0° in the distobuccal root of the maxillary first molar (89/160). ConclusionInsertion paths located at 13 mm above the maxillary occlusal plane in the mesiobuccal root of the maxillary second molar were optimal. A gingival inclination of 70° and a distal inclination of 30° could be beneficial. The distobuccal root of the maxillary first molar region or above the 17 mm insertion plane may not be recommended.

Cortical Bone Thickness and Morphology at the Infrazygomatic Crest Area in Growing Thai Patients with UCLP: A CBCT Study.

To determine and compare buccal cortical bone thickness and morphology (in terms of shape and height) at the infrazygomatic (IZ) crest in growing Thai patients with unilateral cleft lip and palate (UCLP) using cone-beam computed tomography (CBCT) with the ultimate goal of identifying potential sites that are suitable for the placement of miniplates. Prospective study. Institutional research. Twenty-four Thai patients with non-syndromic complete UCLP with Class III skeletal discrepancy aged 10-14 years. A total of 48 CBCT images captured the IZ crest. Five horizontal and six vertical reference planes were established in the IZ crest area. The mean buccal cortical bone thickness of the cleft and non-cleft sides were 1.13 ± 0.45 mm and 1.15 ± 0.46 mm, respectively. The most frequently observed shape for the IZ crest was the external concave contour. There were no statistically significant differences in cortical bone thickness and shape distribution between the cleft and non-cleft sides. (P > .05). The thickness of the buccal cortical bone increased anteriorly and superiorly from V + 0 and H + 0. The average height of IZ crest on the cleft side was 16.20 ± 1.59 mm and 16.78 ± 1.84 mm on the non-cleft side. Notably, significant differences were detected in terms of height between the cleft and non-cleft side and cortical bone thickness by gender (P < .05). The IZ crest was found to provide sufficient support for the insertion of a miniplate, particularly in the superior and anterior regions, ensuring primary stability in growing Thai patients with UCLP.

Quantitative Measurement of Buccal Cortical Bone Thickness in Infrazygomatic Crest Area at Different Alveolar Bone Heights and Insertion Angles of Infrazygomatic Crest Screws: A CBCT Study

Introduction Skeletal anchorage devices for the efficient orthodontic treatment mechanics can be placed at various interradicular and extraradicular sites intra orally. However, their placement in the infrazygomatic crest area can broaden the horizon of orthodontic treatment. The bone thickness in the infrazygomatic crest (IZC) area can vary at different heights and insertion angles during the placement of IZC screws between maxillary second premolar and second molar region. Aims and objectives The purpose of our study was to evaluate the variation in bone thickness in the IZC area at different insertion angles along the mesiobuccal root of maxillary first molar and at different heights from the crest of the alveolar bone in the apical direction between maxillary second premolar and second molar region using cone beam computed tomography, so as to determine the best possible site where the bone thickness will be maximum that will suit to a particular size of IZC screw. Materials and Methods CBCT images of 50 subjects were analyzed by a single observer, the bone thickness in the IZC area was measured and interpreted at different heights from the alveolar crest in the apical direction, that is, 5 mm, 7 mm, 9 mm, 11 mm at six regions between maxillary second premolar and second molar. Bone thickness was also measured at different insertion angles ranging from 55º to 75º to occlusal plane of permanent maxillary first molar along its mesiobuccal root. Results The bone thickness in the IZC area was 4.5 mm–3.5 mm, when it was measured at different angles ranging from 55º to 75º to the occlusal plane of maxillary first molar along its mesiobuccal root with maximum bone thickness at 75° with a mean ± SD of 4.56 ± 1.4. Statistically significant differences in bone thickness were found between maxillary first and second molar on both right and left sides at different heights with maximum bone thickness at 11 mm apical from the alveolar crest with a mean ± SD of 2.03 ± 0.76 and 1.91 ± 0.88, respectively, and along the mesial root of maxillary second molar on right and left sides at 11 mm apical from the alveolar crest with a mean ± SD of 2.12 ± 0.80 and 1.95 ± 0.75, respectively. Conclusions The best site and safe zone for miniscrew insertion in IZC area is at 7 mm to 9 mm distance from the alveolar crest apically along the mesial root of maxillary second molar and at an angle of 55°–75º to the occlusal plane of maxillary first molar, so as to ensure the adequate stability of the miniscrew and without causing any damage to the adjacent anatomical structures.