Three-dimensional occlusal examination of the contacts of maxillary premolars and molars in three different age groups

我们试图确定是否咬合接触上颌前磨牙和磨牙随年龄的变化。对青年、中年和老年三个年龄组各5名受试者进行硅胶咬合记录。受试者没有完全咬合覆盖的牙齿矫正。所有的读数都是在牙尖交错位置最大自主握紧的30%时获得的。使用非接触式三维形状测量装置（Surflacer VMS-250 R，Unisn Inc.，Osaka Japan）对硅胶咬合配准进行数字化。通过CAD软件（Surfacer，Imageware Inc.，美国密歇根州）配备个人电脑。上颌前磨牙的咬合面分为四个区域：颊侧牙尖、舌侧牙尖、近中边缘嵴和远中边缘嵴。上颌磨牙咬合面分为近中颊侧牙尖、远中颊侧牙尖、近中舌侧牙尖、远中舌侧牙尖、近中边缘嵴和远中舌侧牙尖6个区域 ...更多信息 缘脊我们评估了咬合接触，定义为相对牙齿之间的硅胶厚度小于60 μm，并分析了它们的数量、比率、面积和方向。本研究的目的是探讨颞下颌关节噪声（temporomandibular joint，TMJ）对正常人和志愿者下颌骨从习惯咬合位向牙尖交错位位移的影响。颞下颌关节噪声组的下颌位移大于正常组。颞下颌关节噪声组受试者的牙列运动方向均为上级，髁突运动方向均为后向。结果提示，下颌骨从习惯牙合位向牙尖交错位的移位与关节内噪声有关。少

We attempted to determine whether occlusal contacts of the maxillary premolars and molars changed with age. Silicone occlusal registration was taken for five subjects each in three age groups, young, middle-aged and elderly. The subjects had no restorations with full occlusal coverage. All readings were taken at 30% of maximum voluntary clenching in the intercuspal position. A non-contact three-dimensional form measuring device (Surflacer VMS-250R, Unisn Inc., Osaka Japan) digitized the silicone occlusal registration. The three-dimensional data were analyzed by CAD software (Surfacer, Imageware Inc., Michigan USA) with a personal computer. The occlusal surface of the maxillary premolars were divided into four regions: the buccal cusp, lingual cusp, mesial marginal ridge, and distal marginal ridge. The occlusal surface of maxillary molars were divided into six regions: the mesial buccal cusp, distal buccal cusp, mesial lingual cusp, distal lingual cusp, mesial marginal ridge, and distal … More marginal ridge. We evaluated the occlusal contacts, which were defined as less than 60 μm of silicone thickness between opposing teeth, and analyzed their number, rate, area, and orientation. We found that occlusal contacts on the functional cusps were significantly different between the young and middle-aged, and between the young and elderly.The purpose of this study was to clarify the differences in amount and direction of mandibular displacement from habitual occlusal position to intercuspal position, between normal adults and volunteers with temporomandibular joint (TMJ) noise. The mandibular displacement in the volunteers with TMJ noise was larger than that in the normal adults. The direction of MOD (movement of dentition) was superior, and the direction of MOC (movement of condyle) was posterior, in all of the volunteers with TMJ noise. These results suggested that the mandibular displacement from habitual occlusal position to intercuspal position was associated with noise in the joint. Less