Sensitivity and Specificity of Radiographic Methods for Predicting Insertion Torque of Dental Implants
- Autores: Arthur Rodriguez Gonzalez-Cortes, Hazem Eimar, Jorge de Sá Barbosa, Claudio Costa, Emiko Saito Arita, Faleh Tamimi
- Localización: Journal of periodontology, ISSN 0022-3492, Vol. 86, Nº. 5, 2015, págs. 646-655
- Idioma: inglés
- Enlaces
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Resumen
Background: Subjective radiographic classifications of alveolar bone have been proposed and correlated with implant insertion torque (IT). The present diagnostic study aims to identify quantitative bone features influencing IT and to use these findings to develop an objective radiographic classification for predicting IT.
Methods: Demographics, panoramic radiographs (taken at the beginning of dental treatment), and cone-beam computed tomographic scans (taken for implant surgical planning) of 25 patients receiving 31 implants were analyzed. Bone samples retrieved from implant sites were assessed with dual x-ray absorptiometry, microcomputed tomography, and histology. Odds ratio, sensitivity, and specificity of all variables to predict high peak IT were assessed.
Results: A ridge cortical thickness >0.75 mm and a normal appearance of the inferior mandibular cortex were the most sensitive variables for predicting high peak IT (87.5% and 75%, respectively). A classification based on the combination of both variables presented high sensitivity (90.9%) and specificity (100%) for predicting IT.
Conclusions: Within the limitations of this study, the results suggest that it is possible to predict IT accurately based on radiographic findings of the patient. This could be useful in the treatment plan of immediate loading cases.
Success of dental implant osseointegration depends on the density and amount of available bone and on primary implant stability, i.e., the absence of implant mobility in the bone bed after surgical placement.1 One of the indicators of primary stability is the implant insertion torque (IT).2,3 An adequate IT should be ensured to avoid implant micromotion and consequent failure during the osseointegration process.4 In addition, a high IT is one of the factors recommended for immediate loading of the implant, leading to shorter treatments.5-8 Therefore, it could be hypothesized that the ability to predict IT would improve treatment planning, allowing the clinician to choose an adequate implant design, drilling sequence, and loading time.
The influence of alveolar bone characteristics on implant IT has been assessed using different bone density classifications.9-13 One of the most commonly used classifications is based on the amount of cortical and trabecular bone shown in preoperative panoramic and periapical radiographs generating four scores.14 However, this classification has been found to be inaccurate for predicting IT15 because it is subjective and it depends on the opinion of the professional.11 Other measurements, such as cortical thickness of the alveolar ridge, have been found to correlate with IT.16 However, the quantitative relation, as well as sensitivity and specificity of this and other diagnostic methods to predict torque, are not yet available in the literature.
Cone-beam computed tomography (CBCT) allows three-dimensional presurgical morphologic assessment of the cortical and trabecular alveolar bone available for placing dental implants.17 Compared to other CT methods, CBCT offers advantages such as reduced effective radiation doses, shorter acquisition scan time, easier imaging, and lower costs.17,18 CBCT has been validated19 and used clinically20 to assess bone density at implant sites by measuring pixel grayscale values. This analysis has been termed “radiographic bone density.”20-23 The radiographic bone density obtained with CBCT and peak IT has been found to be significantly correlated in both animal10 and human21,24 bone samples. However, none of the abovementioned studies assessed the relative contribution of cortical and trabecular bone on IT. Previous laboratory studies using simulation models16,25 suggest that cortical bone thickness, as well as trabecular bone elastic modulus and strength, may influence implant IT and primary stability.
Panoramic radiographs are useful to diagnose systemic26 and alveolar27 bone quality by assessing the width and shape of the inferior mandibular cortex. These measurements have been described as indices to predict osteoporosis because they are correlated with systemic bone mineral density (BMD) values measured with dual-energy x-ray absorptiometry (DXA).28 Nevertheless, the relation between these indices and implant peak IT remains unknown.
It was hypothesized that quantitative values from radiographic measurements could be used as diagnostic tools for predicting peak IT. Thus, the aims of this diagnostic study were to identify alveolar and systemic bone features that influence peak IT and use this information to develop a clinical method for predicting IT.
