Statement of problem

The relationship between the buccal mucosa-tongue side wall contact points and at what ratio the submucosal tissue (ST) and buccinator muscle (BUC) change during function are unclear.

Purpose

The purpose of this clinical study was to clarify the space and dynamics of the ST and BUC in complete denture wearers by using magnetic resonance imaging and to investigate how denture base shape affects space sealing and the relationship between the ST and BUC.

Material and methods

Eight edentulous participants wearing maxillary and mandibular complete dentures were enrolled. Wax was added to the buccal border of the dentures, and axial and coronal magnetic resonance imaging scans were made during mandibular rest (MR) to observe the relationship of the buccal mucosa and tongue above the retromolar pads. In addition, on axial images, the thicknesses of the ST and BUC were measured at 3 sites: second molar center, second molar distal (SMD), and retromolar pad center (RPC). Coronal images were made during MR, partial mouth opening, and midmouth opening (MMo). At second molar center, SMD, and RPC, the thicknesses of the ST and BUC were measured at the maxillary buccinator attachment region (point A), the mandibular buccinator attachment region (point B), and the median point between A and B (point M).

Results

During MR, contact sealing of the buccal mucosa and tongue on the RPC was noted in 81% of participants. After expanding the denture base with wax, contact was lost in 86% of participants. The ST and BUC thicknesses on the RPC decreased significantly with the addition of wax. During MR, the ST became significantly thicker the further posteriorly it was located. The ST was significantly thicker at point M than at point A for all sections, regardless of mouth opening. The ST and BUC thicknesses in SMD and RPC were significantly thicker at point M than at point B during MR and MMo. The differences of the ST and BUC thicknesses depending on the opening amount were observed only at the point M. In the RPC, the thickness of the ST and BUC decreased significantly as the opening amount increased (ST thickness between MR and partial mouth opening, MR, and MMo: P=.007, P=.001, BUC: P=.018, P=.001, respectively)

Conclusions

The thickness of the ST and BUC differed depending on the site. During mouth opening, these changes in thickness at each site are proportional to the differences in ST and BUC thickness.

中文翻译：

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口腔后粘膜下粘膜下组织和颊肌肌肉动力学的形态学磁共振成像研究：一项临床研究

问题陈述

颊黏膜舌舌侧壁接触点之间的关系以及功能期间黏膜下组织（ST）和胎生肌（BUC）的变化之间的关系尚不清楚。

目的

这项临床研究的目的是通过磁共振成像来弄清楚完整义齿佩戴者中ST和BUC的空间和动力学，并研究义齿基托形状如何影响空间密封以及ST和BUC之间的关系。

材料与方法

入选了八名戴着上颌和下颌全口义齿的无牙参与者。将蜡添加到假牙的颊边界，并在下颌休息（MR）期间进行轴向和冠状磁共振成像扫描，以观察颊黏膜和后磨牙垫上方舌头之间的关系。此外，在轴向图像上，在3个部位测量了ST和BUC的厚度：第二磨牙中心，第二磨牙远端（SMD）和后磨牙垫中心（RPC）。在MR，部分张口和中口张开（MMo）期间制作冠状图像。在第二磨牙中心，SMD和RPC处，分别在上颌buccinator附着区域（A点），下颌buccinator附着区域（B点）以及A和B之间的中点（点）测量ST和BUC的厚度。 M）。

结果

在MR期间，有81％的参与者注意到颊粘膜和舌头在RPC上的接触密封。用蜡扩大义齿基托后，有86％的参与者失去了接触。随着蜡的添加，RPC上的ST和BUC厚度显着降低。在MR期间，ST的位置越靠后，其厚度就会变得越厚。不论张口如何，所有部位的ST点在M点处的厚度都明显大于A点处的厚度。在MR和MMo期间，SMD和RPC中ST和BUC的厚度在M点处的厚度明显大于B点。仅在点M上观察到ST和BUC厚度取决于张开量的差异。在RPC中，ST和BUC的厚度随张开量的增加而显着减小（MR和部分张口之间的ST厚度，MR ，P = .007，P = .001，BUC：分别为P = .018，P = .001）

结论

ST和BUC的厚度因位置而异。在张口期间，每个部位的厚度变化与ST和BUC厚度的差异成正比。