The dimensions of maxillary first molars were investigated and measured using cone beam computed tomography (CBCT) to examine the effectiveness of immediate placement of implants in the maxillary molar area. The CBCT images of 68 patients were collected. The dimensions of the maxillary first molar sockets were measured in both sagittal and coronal aspects, as well as the height of the alveolar bone crest (ABC) to the sinus membrane (SM) at optimal implant position. Sinus membrane and maxillary first molar relationships were analyzed sagittally and coronally. Interradicular bone presence and root intrusion into the sinus (IRS) were also noted. No statistically significant relationship was observed between IRS and age or sex. However, IRS was significantly related to sagittal type, as a type 1 sagittal relationship was characterized by greater root intrusion. The socket dimensions of male subjects were statistically significantly greater than those of female subjects, both coronally and sagittally. Changes in the socket dimensions were not significantly related to age in the sagittal plane. However, coronal plane measurements did increase with age. ABC-SM measurements decreased with age, but these changes were not statistically significant. These results showed that the socket dimensions in the maxillary first molar area are adequate for wider implant placement, but an implant longer than 8 mm increased the risk of perforation. All oral surgeons should be familiar with these anatomical variations so they can adopt appropriate additional practices and inform patients about the risks before operating. Palabras clave: cone beam computed tomography, extraction sockets, immediate implants