Effect of metal artifact reduction level on the assessment of dental implant positioning by cone-beam computed tomography.

OBJECTIVES: This study evaluated the effect of metal artifact reduction (MAR) level and tube current on the assessment of dental implant positioning relative to the mandibular canal (MC) through cone-beam computed tomography (CBCT).

MATERIALS AND METHODS: Titanium dental implants were placed in dried mandibles at 0.5 mm superior to the MC (Group 1/n = 8), 0.5 mm inside the MC with perforation of the cortex (Group 2/n = 10). CBCT scans were obtained with different levels of MAR (off, medium and high) and two tube currents (4 mA and 8 mA). Four examiners analyzed the images and scored the contact between the implant and the MC using a 5-point scale. Sensitivity, specificity, area under receiver operating characteristic curve (ROC) and frequency of scores were calculated. Data were compared with ANOVA two-way and Tukey's test and scores with Chi-Square test.

RESULTS: Specificity and area under ROC curve decreased significantly when MAR level was high compared with MAR-medium and MAR-off. The frequency of score 3 (inconclusive) was the highest, and scores 1 and 5 (definitely no contact and definitely contact, respectively) were the lowest with MAR-high, regardless of the tube current. When MAR was off, there were higher frequencies of scores 1 and 5.

CONCLUSION: The level of MAR influences the assessment of the relationship between the dental implant and the MC. MAR-high led to lower diagnostic accuracy compared with MAR-medium and off.

ADVANCES IN KNOWLEDGE: This paper shows that high level of MAR can interfere in the diagnostic of dental implant positioning relative to the mandibular canal, decreasing its accuracy.