Diagnostic accuracy of 4 intraoral radiographic techniques for misfit detection at the implant abutment joint

Statement of problem. A misfit or gap at the implant abutment joint (IAJ) requires detection as it may compromise the health of the peri-implant tissue. However, which radiographic technique provides the most orthogonal relationship between the central beam and the implant/image receptor is unclear. Purpose. The purpose of this in vitro study was to evaluate the diagnostic accuracy of 4 intraoral radiographic techniques on misfit detection at the IAJ. Material and methods. Twenty implants were placed in polyamide jaws, and customized dental implant abutments with a metal collar were installed. Different gaps were simulated by placing one or three 50-1.1m-thick polyester strips at the IAJ; the absence of the strip represented the control group (no gap). The 4 radiographic techniques were evaluated by using different film holders: a periapical with bisecting angle (PBA), a bitewing interproximal (BI), a periapical with standard paralleling (PSP), and a periapical with modified paralleling (PMP) holder (with a custom-made paralleling index). A total of 240 digital radiographs were evaluated by 4 clinicians experienced with dental implants. Differences were evaluated by using receiver operating characteristic (ROC) curves (Az) and Fisher tests (alpha=.05). Diagnostic values (sensitivity, specificity, accuracy, and positive and negative predictive values) were also obtained. The Kappa test was used to assess intra-and interevaluator reproducibility, which ranged from moderate to almost perfect. Results. All diagnostic values, except specificity, were lower for the PBA technique for both the 50 and 150-mu m gaps. Az values for the PBA technique were significantly lower than those obtained for the other 3 techniques (P<.05), which did not differ from each other. The 150-mu m gaps were more easily detected than the 50-mu m gaps only for PBA (P<.05). Conclusions. The BI, PSP, and PMP techniques detected misfits at the IAJ most accurately. The PBA technique is not recommended for this purpose.