Implications of Virtual CBCT-Based Immediate Implant Planning for Maxillary and Mandibular First Molars
The purpose of his study was to investigate the projected ridge-implant dimensions derived from virtual superimposition of implants on intact first molars mimicking immediate implantation in the mandible (Md1) and maxilla (Mx1) using cone-beam computed tomography (CBCT). The CBCT records of 41 patients (19 males and 22 females) with Md1 or Mx1 were collected. Ten-millimeter-long cylindrical implants with different diameters were virtually positioned at prosthetically ideal angles into interradicular septum using CBCT software. Radiographic alveolar ridge height (ARH), alveolar ridge width (ARW), gap distance, and vertical distance from the implant platform to the alveolar crest were measured. Twenty Mx1s (48.8%) and 21 Md1s (51.2%) were included. The mean ARH values were 7.13 ± 4.32 and 15.64 ± 1.80 mm for Mx1 and Md1, respectively; 87.8% of mesiobuccal sites had gap distance of >2 mm when 6-mm-diameter implants were used. Increasing implant diameter from 6 to 9 mm decreased the percentage of sites with ARW > 2 mm from 80.5% to 41.5% buccally and from 86.4% to 26.8% lingually. The mean vertical distance from the implant platform to the alveolar crest was 1.41 ± 1.09 mm buccally and 1.11 ± 1.10 mm lingually. Immediate implant placement of first molars, especially in the maxilla, requires stringent presurgical evaluation. Implants no wider than 6 mm placed into the interradicular septum may meet acceptable running room and alveolar plate thickness criteria if the jumping distance is grafted. Further clinical trials are needed to confirm these findings in this virtual study
Description of CBCT measurements. (a) (a, b, c, d) Gap distance: the maximum distance from the implant surface to the inner aspect of the alveolar plate at the level of the implant platform. (e, f, g) Bone plate thickness (BPT): the thickness of the alveolar plate at the level of the interradicular septal crest. (b) (a, b) Alveolar ridge width (ARW): the distance from the implant surface to the outer surface of the alveolar bone plate at the level of the implant platform. *Area of bone-covered implant surface: the percentage of implant surface covered by alveolar bone expressed as the ratio of the angle corresponding to the arc covered by bone tissue.
Area of bone-covered implant surface of maxillary and mandibular first molars at different levels around virtual 4.8-mm × 10-mm implants.
The percentage of sites with gap distance greater than 2 mm around virtual implants with different diameters.
The percentage of sites with ARW greater than 2 mm around virtual implants with different diameters.
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