Department of Prosthodontics, University of Athens, Athens, Greece.
J Esthet Restor Dent. 2010 Aug;22(4):235-50. doi: 10.1111/j.1708-8240.2010.00345.x.
The detection of marginal gaps at the implant-abutment interface is a common clinical task in prosthodontic treatment. For the detection of the gap intraorally, especially under thick soft tissues the most common method is dental radiography.
The objective of this experimental study was to investigate the accuracy of conservative dental radiography to detect marginal gaps at the implant-abutment interface. For these reasons radiographs were taken on internal and external hex implants with different experimental gaps and inclinations.
The abutment (with a space created by plastic sheets 0.5 and 0.2 mm in thickness) was screwed on the implant, and the implant was placed into a box filled with silicone impression material. The X-ray film was placed parallel to the implant at the back of the box, the borders of the box were marked to the base and the box. A ruler of 10 cm was fixed at a long X-ray tube to ensure parallelism to the implant, X-ray film. Sets of radiographs were made at 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees (to the abutment) and -5 degrees, -10 degrees, -15 degrees, -20 degrees, -25 degrees, -30 degrees (to the implant) degrees. The X-ray images were observed with visual examination, under magnification, and in higher magnification in a slide projector. The phenomenal and the true gap at the implant-abutment interface were calculated in order to determine the distortion.
There were significant differences between the internal and external hex implants because of the different morphology of the implants. The detecting ability to diagnose a gap at the implant-abutment interface varied significantly with the angulation degree of the X-ray tube. At inclinations to the implant (- inclination) the gap diminished earlier than those inclinations to the prosthetic abutment (+ inclinations). In all examinations the gap was not detectable at angulations higher than 20 degrees. In visual examination at 25 degrees and 30 degrees an average clinician could diagnose the distortion.
The X-ray diagnosis of gap at the interface can be significantly influenced by the inclination of the X-ray tube in relation to the long axis of the implant. To achieve accurate results, the use of a paralleling device is advocated in order to achieve greater detection ability.
Dental radiography is often used for detection of marginal gaps at the implant-abutment interface. The angulation of the X-ray beam may lead to inaccurate diagnosis in gap detection. The use of a paralleling device is indicated for evaluation of marginal accuracy. The geometry of the implant (internal or external hexagon) influences the gap evaluation.
在修复治疗中，检测种植体-基台界面的边缘间隙是一项常见的临床任务。对于口腔内间隙的检测，尤其是在软组织较厚的情况下，最常用的方法是牙科放射照相术。
本实验研究的目的是研究保守性牙科放射照相术检测种植体-基台界面边缘间隙的准确性。为此，对具有不同实验间隙和倾斜度的内六角和外六角种植体进行了放射照相。
将基台（用 0.5 和 0.2 毫米厚的塑料片制成的间隙）拧到种植体上，然后将种植体放入充满硅橡胶印模材料的盒子中。将 X 光片平行放置在盒子背面的种植体上，将盒子的边界标记到底部和盒子上。将一个 10 厘米长的标尺固定在长 X 光管上，以确保与种植体、X 光片平行。在 0 度、5 度、10 度、15 度、20 度、25 度、30 度（至基台）和-5 度、-10 度、-15 度、-20 度、-25 度、-30 度（至种植体）的角度拍摄一系列 X 光片。使用视觉检查、放大和幻灯片投影仪中的更高放大倍数观察 X 射线图像。为了确定失真，计算了种植体-基台界面处的实际和表观间隙。
由于种植体形态不同，内六角和外六角种植体之间存在显著差异。X 射线管的角度对诊断种植体-基台界面间隙的能力有显著影响。对于向种植体倾斜（-倾斜），间隙比向修复基台倾斜（+倾斜）更早减小。在所有检查中，当角度高于 20 度时，间隙无法检测到。在 25 度和 30 度的视觉检查中，普通临床医生可以诊断出这种扭曲。
X 射线诊断界面处的间隙会受到 X 射线管相对于种植体长轴倾斜度的显著影响。为了获得准确的结果，建议使用平行设备以获得更大的检测能力。
牙科放射照相术常用于检测种植体-基台界面的边缘间隙。射线束的角度可能导致间隙检测不准确。使用平行设备可用于评估边缘精度。种植体的几何形状（内六角或外六角）会影响间隙评估。
