ABSTRACT
Nowadays, most recently emerged Cone Beam Computed Tomography (CBCT), specialized equipment was developed to produce image of the head and neck, which combines the advantage of providing higher resolution images to deliver smaller radiation doses and imply lower costs compared to conventional tomography. (1, 6)
However, CBCT also has some disadvantages, emitting a dose of scattered radiation, detectors having x-ray area with limited dynamic range. It is not even possible to establish a direct correlation between the density values and bone quality (9). So the need to develop an accurate objective method for evaluation of bone density is of the utmost importance. (1)
The concept of primary stability is related to the lack of mobility of the implant after its placement in the implant bed, being influenced by implant design, insertion technique and bone quality. (3, 5)
1 INTRODUCTION
Over the past years, the literature has shown that the success of rehabilitation with dental implants depends on the amount and quality of available bone for placement. In this sense, it is essential that the assessment of bone structure prior to implant placement is of great precision. (1-3)
The recently developed study by Bayarchimeg in 2013 warned that the initial stability of the implant is not only influenced by the decrease in the size of the final drill preparation with the goal of increasing insertion torque, but mainly by the density of the bone and its cortical thickness. (3, 4)
In 2008, Misch used computed tomography to objectively classify the type of bone into 5 categories based on Hounsfield units (HU, 1985). This classification allowed categorizing bone density more accurately than previously proposed by Lekholm and Zarb, and more widely used. (1, 5-8)
The survival rate of implants that remain mobile after loading in 3 years is much lower than the ones with good primary stability. It is reasonable to assume that in the pre-surgical evaluation, we will be able to predict primary stability by the bone density site. (1, 6)
The implant stability can be assessed noninvasively through the insertion torque test and by radio-frequency, with great precision, measuring the consistency of bone/implant complex using the Osstell. (1, 8, 10, 11)
In 2012, a systematic review by Marquezan noted a strong correlation between insertion torque and density measured in CBCT images with Hounsfield Units. (5)
The present study aims are to evaluate whether a relationship between the amount of bone density, measured by means of a conical beam CT (CBCT) in the preoperative phase, the value of insertion torque during implant placement and the implant quotient stability (ISQ) measured by radio-frequency (Osstell) after implant placement exist.
