Tomographic assessment of infrazygomatic crest bone depth for extra‐alveolar miniscrew insertion in subjects with different vertical and sagittal skeletal patterns

Abstract

Objective To evaluate bone availability at the infrazygomatic crest for extra‐alveolar bone miniscrew insertion in subjects with different vertical and sagittal skeletal patterns. Setting and sample population Measurements of the infrazygomatic crest were performed on multislice computed tomography scans from 58 adults with different skeletal patterns. Materials and methods Infrazygomatic crest bone depth was measured at 4, 5 and 6 mm from the cementoenamel junction (CEJ) of the maxillary first molar at three different angles (60°, 70° and 80°) in the first molar occlusal plane. The sagittal and vertical skeletal patterns were determined. Analysis of variance followed by Tukey's post hoc test was used (P ≤ .05). Results Bone depth was greater near the CEJ (8.7 ± 3.1 mm) and lower in the apical area (5.8 ± 2.7 mm). In Class II subjects, considering 6 mm from the CEJ, there was a significantly lower depth at the 80° angle (5.4 ± 2.5 mm) than at 60° (8.6 ± 3.5 mm; P = .007). In mesofacial subjects, considering 5 and 6 mm from the CEJ, bone depth was lower at 80° (5.7 ± 3.2 mm and 5.3 ± 2.5 mm) than at 60° considering 4 mm from the CEJ (P ≤ .019). Conclusion Bone availability was lower at the apical level, especially in Class II and mesofacial subjects. Therefore, when the planned insertion site is located in the apical direction, it is recommended to choose shorter miniscrews (2.0 x 12mm) and a smaller insertion angle (60°) and/or to plan a miniscrew bone insertion deep enough to allow bicortical fixation.

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

“…Besides the insertion region, the height of the insertion and the gingival slope can directly affect bone depth [ 9 ]. We found that as the height of the insertion increased, bone depth tended to decrease and the ratio of bone deficiency increased, which was in agreement with previous studies [ 12 , 16 , 17 ]. Regarding soft tissue, high degree of insertion at the alveolar mucosa will frequently cause mucosal inflammation, soft tissue embedment, or patient discomfort.…”

“…Although few studies have investigated the bone depth in the U7M region, thicker buccal alveolar bone has been reported [ 21 , 27 ], which can probably explain our findings. Previous studies considered U6 as a common region for insertion in the IZC [ 9 , 12 , 14 , 16 ], but in recent years, growing research has focused on region U67 instead for rich bone mass [ 17 , 18 , 20 ]. However, there is a risk that the miniscrew might injure or block the root of U6 if it is inserted into the narrow radicular region of U67, especially during the molar distalization movement.…”

“…Multiple studies have used cone beam computed tomography (CBCT) analysis to assess the buccal bone in the IZC [ [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] ]. However, most of these have only measured buccal bone thickness or bone depth in a constant two-dimensional section and simply addressed the impact of insertion height and gingival inclination on bone depth.…”

Revisiting the Complications of Orthodontic Miniscrew

“…In the palate, distance to the nasal cavity and maxillary sinus was greatest in the region mesial to the first premolar and then the distance started to decrease significantly [36]. In the buccal area, perpendicular insertion was safe with minimal risk of sinus or nasal cavity injury, while oblique placement increased the possibility of sinus and Schneiderian membrane penetration [36][37][38].…”

Influence of the palatal plane cant and skeletal patterns in the hard palate thickness?

“…Miranda-Viana et al 14 observed that there are different morphological patterns of the hard palate; thus, knowledge about the skeletal patterns can provide information for orthodontic and surgical interventions. Studies using CT have shown that vertical and sagittal facial skeletal patterns can influence the anatomy of certain bone structures that are insertion sites for orthodontic miniscrews, such as the mandibular symphysis, 15 alveolar and cortical bone, 16 infrazygomatic crest 17,18 and buccal shelf. 19 To the best of our knowledge, no study evaluated the relationship between hard palate thickness and different skeletal patterns aiming the MARPE miniscrew insertion.…”