CBCT-based simulation of mandibular buccal shelf miniscrew insertion: Influence of angulation, facial pattern, sex and side on simulated miniscrew trajectory length: A retrospective study.

ObjectiveTo identify optimal areas for the insertion of extra-alveolar miniscrews into the infrazygomatic crest (IZC) and mandibular buccal shelf (MBS), using cone beam computed tomography (CBCT) imaging in patients with different craniofacial patterns.MethodsCBCT reconstructions of untreated individuals were used to evaluate the IZC and MBS areas. The participants were divided into three groups, based on the craniofacial pattern, namely, brachyfacial (n = 15; mean age, 23.3 years), mesofacial (n = 15; mean age, 19.24 years), and dolichofacial (n = 15; mean age, 17.79 years). In the IZC, the evaluated areas were at 11, 13, and 15 mm above the buccal cusp tips of the right and left first molars. In the MBS, the evaluated areas were at the projections of the first molars’ distal roots and second molars’ mesial and distal roots, at a 4- and 8-mm distance from the cementoenamel junction. Intergroup comparisons were performed with analysis of variance and the Tukey test.ResultsThere was no statistically significant difference in the IZC bone thickness among the groups. For MBS bone availability, some comparisons revealed no difference; meanwhile, other comparisons revealed increased MBS bone thickness in the brachyfacial (first molars distal roots) and dolichofacial (second molars mesial and distal roots) patterns.ConclusionsThere was no significant difference in the IZC bone thickness among the groups. The facial skeletal pattern may affect the availability of ideal bone thickness for the insertion of extra-alveolar miniscrews in the MBS region; however, this variability is unlikely to be clinically meaningful.

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 <22°); GROUP B: average growth pattern (FMA 22°-28°); GROUP C: vertical growth pattern(FMA >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.

IntroductionThe mandibular buccal shelf is a reliable site for extra-alveolar orthodontic miniscrew placement. The primary stability of temporary anchorage devices depends largely on cortical bone thickness and overall bone morphology. However, age-related variations in buccal shelf bone dimensions have not been fully established, particularly between adolescents and adults with similar growth patterns. The aim of the present study was to evaluate and compare the vertical and horizontal bone thickness of the mandibular buccal shelf in adolescent and adult populations using cone-beam computed tomography (CBCT).Materials and methodsThis retrospective cross-sectional study included 60 CBCT scans divided into two groups: adolescents (12-18 years) and adults (19-35 years), with 30 subjects in each group. Only individuals with average growth patterns and complete permanent dentition were included in the study. Vertical bone thickness was measured at 3, 5, and 7 mm apical to the cemento-enamel junction (CEJ) at three locations: mesial to the first molar, between the first and second molars, and distal to the second molar. Horizontal thickness was assessed at 6 mm and 11 mm apical to the CEJ at the corresponding sites. The measurements were performed bilaterally and averaged. Data were analyzed using mixed-model analysis of variance (ANOVA), with significance set at p<0.05.ResultsVertical bone thickness increased with depth and showed significant site-related variations. Adults demonstrated significantly greater vertical thickness at deeper levels, particularly in the inter-radicular regions. Horizontal thickness also increased apically, with adults showing greater values at the mesial and inter-radicular sites. The region distal to the second molar consistently exhibited favorable dimensions in both the groups.ConclusionThe thickness of the mandibular buccal shelf bone varies according to age, depth, and location. Adults demonstrate more favorable bone dimensions for miniscrew stability, particularly in the deeper and inter-radicular regions. CBCT-based individualized assessment is recommended for optimal extra-alveolar anchorage planning.

Background: To evaluate different anatomical sites in buccal shelf region at different levels (4mm, 6mm, 8mm, 10mm) from cemento-enamel junction for mini screw insertion in skeletal class II and class III patients using cone beam computed tomography (CBCT). Materials and Methods: The sample consists of cone beam computed tomography images of 48 subjects (24 skeletal class II and 24 skeletal class III) were evaluated. Mandibular buccal shelf area was evaluated at the regions (i) mesial to lower first molar (ML6) (ii) between the mesiodistal roots of the first molar (iii) distal to lower first molar (DL6) (iv) mesial to lower second molar (ML7) (v) between mesiodistal roots of the second molar (vi) distal to lower second molar (DL7) and cortical bone thickness was determined at 4, 6, 8, 10 mm level from cemento-enamel junction Results: Mandibular buccal shelf bone thickness increases from mesial surface of first molar to distal surface of second molar and from cemento-enamel junction to 8 mm level. Comparative evaluation between class II and class III shows significant differences (p&lt;0.05) at the level of 8mm distal to second molar in the mandibular buccal shelf region. Conclusion: Skeletal class III subjects have more cortical bone thickness than class II subjects at the level of 8mm distal to second molar in the buccal shelf region.

A<sc>BSTRACT</sc>Background:The continuous evolution in orthodontics introduces innovative materials and methods to enhance treatment efficacy. Among these advancements, orthodontic anchorage screws, particularly miniscrews, have revolutionized treatments by offering diverse nonsurgical solutions for managing space discrepancies and certain skeletal malocclusions. The success of miniscrews is influenced by various factors including patient-related factors (age, sex, skeletal pattern, and oral hygiene), miniscrew-related factors (diameter, length, shape), and treatment-related factors (technique, applied forces, and insertion site).Materials and Methods:This study used Cone Beam Computed Tomography (CBCT) to evaluate the mandibular buccal shelf area for miniscrew placement across different sagittal and vertical skeletal patterns in 63 subjects, categorized based on the ANB angle and Jarabak ratio into Class I, II, III, and horizontal, average, and vertical growth patterns, respectively. Measurements were taken at specific sites related to the mandibular first and second molars, focusing on angulation, buccal bone depth (4mm and 6mm from the cementoenamel junction), and buccal bone thickness (6mm and 11mm from the cementoenamel junction).Results:There were no significant statistical differences in any measurement between the right and left hemiarches. The values for the bone around the distal root of the mandibular second molar were significantly greater than the other values. With regard to Sagittal Skeletal Pattern, Class I cases showed greater values as compared to Class II and Class III with a significant difference in the angulation, bone depth, and thickness at 11 mm from CEJ. Although values tended to be greater in patients with horizontal growth pattern, the difference was not statistically significant.Conclusion:Mandibular buccal shelf provides an optimal bone site for miniscrew insertion with better osseous characteristics at the distal root of the mandibular second molar. Subjects with skeletal Class I and horizontal growth pattern exhibit the most favorable osseous characteristics in the MBS area. However, in terms of bone thickness at 6 mm from CEJ Class III cases showed significant difference compared to Class I and Class II.

Mandibular buccal shelf and infrazygomatic crest thicknesses in patients with different vertical facial heights

ObjectiveTo 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.MethodsThis 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.ResultsThere 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.ConclusionsMBS 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.

Association between gonial angle and bone thickness in the infrazygomatic crest and mandibular buccal shelf regions for mini-screw insertion in adults: A retrospective study.

Comparison of mandibular buccal shelf morphology between adolescents and adults with different vertical patterns using CBCT.

Mandibular buccal shelf (MBS) offers good quality and quantity of bone for orthodontic bone screw (OBS) insertion. Despite several reports of treated patients, there are numerous variables in selecting the exact placement site for OBS placement in the MBS. There are also anatomical variations in this area which must be considered. This study aims to measure and compare the MBS bone characteristics for OBS placement using cone beam computed tomography (CBCT) between two different facial types. Eighty CBCT samples were collected (40 samples of group A horizontal growers and 40 of group B vertical growers). Each CBCT image was reconstructed and oriented with CS 3D CBCT software. The cortical bone thickness, the slope of the MBS, and buccolingual inclination of mandibular second molar were measured and analysed. Cortical bone thickness among horizontal growers was 5.23 ± 0.58 mm and among vertical growers was 4.85 ± 0.37 mm. The slope of MBS among horizontal growers was 60.83 ± 6.15 degrees and among vertical growers was 66.75 ± 6.27 degrees. In both the parameters there was a statistically significant difference between the groups. There was no significant difference between the groups for the buccolingual inclination of 2nd molar. Increased cortical bone thickness and the flatter slope of MBS at the 2nd molar region allows for easier placement of OBS in horizontal growers than in vertical growers.

Objectives To compare bone thickness, bone height, and density in the infrazygomatic crest (IZC) and the mandibular buccal shelf (MBS) associated with different sagittal skeletal patterns. Material and Methods This retrospective study included three groups of which a Class I group consisted of 28 patients (24 female, 4 male, mean age: 26.46 ± 6.1), a Class II group comprised 31 patients (28 female, 3 male, mean age: 30.08 ± 5.9), and a Class III group included 26 patients (22 female, 4 male, mean age: 26.21 ± 5.3). Evaluations of bone characteristics were performed for both the IZC and MBS using cone-beam computed tomography (CBCT). Maxillary length and mandibular body length were also measured on lateral cephalograms. One-way ANOVA, chi-squared, and Spearman’s correlation tests were applied for statistical analysis. Results The Class II group showed significantly greater bone thickness at the distal root level of the maxillary second molar in IZC ( p &lt; 0.05). While bone thickness showed no statistically significant difference in the MBS between the groups ( p &gt; 0.05), the Class II group showed significantly higher bone height values at the distal root level of the mandibular second molar in the MBS ( p &lt; 0.05). A statistically significant increase from the mesial aspect to the distal aspect was observed in total bone thickness in the Class I group and total bone thickness and height in the Class II and III groups in the MBS. The mandibular body length and SNB values were positively correlated with the total bone thickness and bone height of the MBS. Conclusions Bone thickness in the IZC and bone density in both the IZC and MBS were similar in the different sagittal skeletal patterns. Total bone thickness in the Class I and III groups and the total bone height in the Class II group showed a gradual increase from the mesial to the distal in the MBS. The length of the mandibular body may be a clinical clue to assist in the selection of the appropriate implantation area.

Objectives To seek information regarding the relationship between the quantity of alveolar bone and the angle and sagittal position of the incisors. This was to be further determined in relation to the basal bones and facial pattern with the aim of establishing a predictive model based on the study of a lateral cephalogram. Methods The distance from the cemento-enamel junction to the labial alveolar crest and the bone thickness half-way along the root of the most prominent upper and lower incisor were measured in a sample of 100 cone beam computed tomography (CBCT) scans of patients aged between 15 and 34 years. Lateral cephalograms of the patients were extracted from the scans and used to measure the buccolingual angle and antero-posterior position of the incisors in addition to the facial pattern of each patient. Results A correlation was found between bone thickness around the upper incisor and the variables of the incisal angle and its sagittal position. The inclination of the lower incisor (IMPA) was related to cortical bone thickness. The cemento-enamel junction to alveolar crest measurement (bone height) was related to the antero-posterior position of the lower incisor in men. The facial pattern was unrelated to any of the variables. Conclusions The angle and sagittal position of the upper and lower incisors were associated with alveolar bone thickness in men. Only the antero-posterior position of the lower incisor was related to its alveolar bone height. In women, only the angle of the lower incisor was associated with bone thickness.

Introduction: The infrazygomatic crest (IZC) is an alternative site for miniscrew anchorage. It is important to analyze the anatomy of the region during preoperative planning to minimize the risk of unwanted tooth movement and injury to the vital structures. The literatures on the clinical application of miniscrew in IZC is scarce. Objective: To determine bone thickness, height and angle of insertion of miniscrew in the IZC region. Materials and methods: This cross-sectional observational comparative study included 44 patients above18 years. IZC bone thickness and height of miniscrew insertion were measured on cone-beam computed tomographic (CBCT) records. Student t-test was done to compare the bone thickness and insertion height between gender and between sides. Results: Infrazygomatic crest bone thickness when measured at an angle of 40° to 75° and 11 to 17 mm above the occlusal plane of the maxillary first molar was 3 to 9 mm. There was no significant gender and side variation in bone thickness of IZC and insertion height. Conclusion: Infrazygomatic crest thickness increases with the increase in insertion angle and the decrease in height. The optimal site for miniscrew placement in IZC in an adult is at the angle of 70°and 13 mm from the occlusal plane in the Nepali sample.

Background Computed tomographic evaluation of mandibular buccal shelf region in skeletal class III malocclusion cone beam computed tomography (CBCT) studies have been reported to have great alteration in the thickness of mandibular buccal shelf region owing to the different growth patterns and ethnic variations. The aim of this study was to determine the total and cortical bone thicknessin the mandibularbuccal shelf(MBS) region for extra-alveolar mini-screw placement in South Indian patients with sagittal skeletal class III malocclusion. Material and methods This retrospective computed tomographic study consisted of archived files of the Dravidian population with class III skeletal base that met the eligibility criteria. The total bone and cortical bone thickness of the buccal shelf regions were evaluated in relation to three anatomical sites at various depths and angulations. One-way ANOVA and Tukey honestly significant difference (HSD) post hoc tests were used for statistical analysis. Pearson correlation coefficient was performed to compare if any relation existed between bone thickness and the growth pattern. Results The maximum bone thickness in the buccal shelf region in our study was found at the distal portion of the second molar root, 8-12 mm from its cementoenamel junction (CEJ) and at 30-45 ° angulation (p-value<0.005). There was a positive correlation between the hypo-divergent growth pattern and the thickness of the bone. Conclusion Based on the sites recorded, the preferred site for mini screw placement in Class III patients is the distobuccal cusp region with respect to the second molarat a depth of 8-12 mmand at angulation of 30-45 °. There was a moderate correlation with hypo-divergent growth patterns, suggestive of a wider and thicker mandibular buccal shelf region in these subjects.

Objectives The objectives of this article were to analyze the bone thickness and bone depth in the mandibular buccal shelf area at four sites, that is, a mesiobuccal section of mandibular first and second molar and distobuccal section of first and second molar and to analyze the bone thickness and bone height with respect to the spatial position of inferior alveolar nerve canal (IANC) at the right and left side and in males and females. Material and Methods Cone-beam computed tomography scans of 34 individuals were analyzed at four sites, that is, mesiobuccal section of the mandibular first and second molar and distobuccal section of first and second molar at both right and left sides and bone thickness as well as the bone depth of buccal shelf and IANC was measured and compared between right and left side and in between males and females. Results Bone thickness increased progressively in the distal direction. The highest bone depth was recorded in the distobuccal section of the second molar. IANC was also mapped and the result showed that the bone height from the cementoenamel junction (CEJ) to IANC decreased posteriorly but the bone depth was &gt;18 mm at all sites. Very few parameters showed statistically significant differences between the right and left sides. Bone height to IANC from CEJ showed statistically significant differences between genders at a few sites with male subjects having higher values. Bone thickness in the IANC region showed no gender dimorphism. Conclusion The appropriate site for mandibular buccal shelf mini-implant placement is the distobuccal region of the mandibular second molar.