The clinical fate of hydroxyapatite-coated titanium endosseous implants is controversial. Some researchers have found that coating implants with hydroxyapatite is advantageous, reporting significant success rates. Those researchers believe that the reasons reported for the failures (coating dissolution and increased microbial adhesion) no longer exist. Those who believe that hydroxyapatite-coated implants are not so advantageous admit there are short-term successes, but they believe coated implants will not have long-term success rates seen with the noncoated titanium implants.; In an attempt to diminish the controversy that exists, much work has been performed to analyze the biomaterials and biomechanics of various implant systems as well as to analyze the implant-bone interface. However little has been done to analyze the bone structure around the implant in human subjects. Fractal dimension analysis is a means of analyzing trabecular bone density and, to a degree, quality. Given this technique we hypothesize that fractal dimension analysis can be used to study the bone around implants and that there is a difference of fractal dimension between bone near hydroxyapatite-coated and noncoated implants.; An algorithm was developed using a surface area technique of fractal dimension. Our algorithm was first validated by using blocks of varying degrees of perceived roughness and then by using digitized dental radiographs of patients with osteoporosis/osteopenia. In both cases, a high fractal dimension was found to be associated with the low-density structure or with the image of greater perceived roughness. These results were not statistically significant (p > .05). However, they were sufficient to proceed with the main focus of this research.; The algorithm was then applied to digitized dental radiographs of hydroxyapatite-coated and noncoated endosseous dental implants taken over a 4-year period. There was no statistically significant difference between fractal dimension of bone near the 2 implant types, but there was a statistically significant difference between fractal dimension of the bone near the implants at the time of loading of the dental prosthesis (baseline) and 1 year of loading for both implant types (p .05). Also, other researchers have seen no difference in clinical performance of these same implants. The hydroxyapatite-coated implants did have a higher fractal dimension for Years 1, 2, 3, and 4, which our algorithm indicates is a lower density situation.
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机译：羟基磷灰石涂层钛质骨内植入物的临床命运是有争议的。一些研究人员发现，用羟基磷灰石涂层植入物是有利的，据报道其成功率很高。这些研究人员认为，报道失败的原因（涂层溶解和微生物附着力增加）已不复存在。那些认为羟基磷灰石涂层的植入物并不是那么有利，那些承认短期成功的人，但是他们相信涂层的植入物不会有非涂层的钛植入物看到的长期成功率。为了减少存在的争议，已经进行了很多工作来分析各种植入物系统的生物材料和生物力学以及分析植入物与骨的界面。然而，在人类受试者中几乎没有做过分析植入物周围的骨骼结构的工作。分形维数分析是一种分析小梁骨密度以及一定程度质量的方法。使用这种技术，我们假设可以使用分形维数分析来研究植入物周围的骨头，并且在羟基磷灰石涂层和未涂层的植入物附近的骨头之间，分形维数存在差异。使用分形维数的表面积技术开发了一种算法。我们的算法首先通过使用不同程度的可感知粗糙度的块进行验证，然后通过使用骨质疏松症/骨质减少症患者的数字化牙科X线照片进行验证。在这两种情况下，都发现高分形维数与低密度结构或具有更大的感知粗糙度的图像有关。这些结果没有统计学意义（ p p <.05）。另外，其他研究人员也没有发现这些相同植入物的临床性能也没有差异。羟基磷灰石涂层植入物在第1、2、3和4年确实具有较高的分形维数，我们的算法表明这是较低密度的情况。
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