Zygomaticomaxillary suture maturation: A predictor of maxillary protraction? Part I - A classification method

Abstract

Objective: The aim of this study was to present a method of classifying the maturational level of the zygomaticomaxillary sutures (ZMSs).

Methods: Cone-beam CT (CBCT) images from 74 subjects (5.6-58.4 years) were examined to define the radiographic stages of ZMS maturation. Five stages of maturation of the ZMS were identified and defined: Stage A-uniform high-density sutural line, with no or little interdigitation; Stage B-scalloped appearance of the high-density sutural line; Stage C-two parallel, scalloped, high-density lines, separated in some areas by small low-density spaces; Stage D-fusion in the inferior portion of the suture; and Stage E-complete fusion. Intra- and inter-examiner agreements were evaluated by weighted kappa tests.

Results: The intra- and inter-examiners reproducibility values demonstrated substantial to almost perfect agreement. No fusion of ZMSs was observed in patients up to 10 years of age. From 10 to 15 years, all maturational stages were identified. After 15 years of age, the majority of patients showed fusion of ZMSs.

Conclusions: The classification of ZMS maturation using CBCT is a reliable method that allows the assessment of the morphology of the ZMSs in the individual patient.

Keywords: cone-beam computed tomography; cranial sutures; growth and development.

FIGURE 1

The maxillary sutures: (A) Frontomaxillary sutures (FMS), zygomaticomaxillary sutures (ZMS), midpalatal suture (MPS). (B) Midpalatal and transverse (TPS) palatine sutures [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 2

Use of head orientation tools to position the patient’s head (roll, pitch and/or yaw) for better visualization of the ZMS after image acquisition [Colour figure can be viewed at wileyonlinelibrfary.com]

FIGURE 3

Visualization of the ZMS: in the sagittal view, the horizontal cursor (orange line) is placed at the tip of the nose parallel to the palatal plane (B). Note that in the axial view, the zygomaticomaxillary sutures are seen bilaterally (A) (arrows). The vertical cursor (green line) should be positioned on the midsagittal plane of the patient (C) [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 4

Visualization of the ZMS: in the axial view, the anteroposterior cursor (purple line) is positioned transversely through the ZMSs bilaterally (A). This approach allows the visualization of the ZMSs in the coronal view bilaterally (C)—(arrows) [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 5

Visualization of the ZMS: in the coronal view (C), the vertical cursor (green line) then is positioned along the ZMS on the left side (yellow arrow) to allow clinicians to scroll along the suture and visualize its tortuous path and portions. The suture then is visualized in all multiplanar views (axial in A, sagittal in B and coronal in C views) (D) Close-up view of (B) sagittal view, where the maturation of the ZMS is identified (green arrow) [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 6

Sagittal view of the inferior portion of the ZMS. Note the inferior portion is more lateral and may overlap view of the cortical bone, with the false appearance of fusion (arrow) [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 7

Proper radiographic interpretation of the maturational stage of the inferior portion of the ZMS requires rolling the patient’s head in a counterclockwise direction in the coronal view (C) until the inferior portion of the ZMS is visualized properly in the sagittal view (B). (D) Close-up view of the inferior portion of the left ZMS [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 8

Proper radiographic interpretation of the maturational stage of the inferior portion of the right ZMS requires rolling the patient’s head in a clockwise direction in the coronal view (C) until the inferior portion of the ZMS is visualized properly in the sagittal view (B). (D) Close-up view of the inferior portion of the right ZMS [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 9

Stage A: the ZMS is a uniform high-density line (no or little interdigitation), with decreased parasutural bone density at infraorbital (A) and infrazygomatic (B) portions of this suture

FIGURE 10

Stage B: the ZMS is visualized as a thicker scalloped high density line with some interdigitation at Stage B. In a late Stage B, a thicker scalloped high-density line can be seen in some areas, and in other areas, two thin, parallel, scalloped, high-density lines close to each other and separated by small low-density spaces (arrow) can already be seen at superior (A) and inferior (B) portions. The parasutural bone density still is decreased [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 11

Stage C: the ZMS can be seen as two thin, parallel, scalloped, high-density lines that are close to each other and separated by small low-density spaces in the zygomatic and maxillary bones at superior (A) and inferior portions (B). The parasutural bone density still is decreased

FIGURE 12

Stage D: the ZMS cannot be visualized at least in a portion of the ZMS, (A), usually in most inferior part (B—arrow), where the fusion has occurred. The parasutural bone density is increased in this portion [Colour figure can be viewed at wileyonlinelibrary.com]

FIGURE 13

Stage E: the ZMS is not visible in many areas along the suture, where fusion of the suture has occurred. The density of the parasutural bone is increased

FIGURE 14

For patients who present wide maxillary sinus, the ZMSs can be placed on the lateral wall of the maxillary sinus [Colour figure can be viewed at wileyonlinelibrary.com]