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11 Implant Tribune Italian Edition - Settembre 2016 Ricerca & Clinica Il concetto Platform-Switch Platform-Switch • Migliore condizionamento dei tessuti molli • Migliore mantenimento dei livelli di osso crestale • Supportato da studi clinici 32670074-IT-1607 © 2016 DENTSPY Implants. Tutti i diritti riservati. NOVITA‘ Abutment XiVE ® PS www.dentsply.com < pagina 10 Katakami et al. observed anastomo- ses between the lateral lingual ca- nals and the inferior alveolar canal in 20.1% of the cases6,21 . The inferior alveolar artery provides an intraos- seous blood supply to the symphy- seal area and the mandibular inci- sors by an incisal branch that runs through the incisal canal. This canal has an average length of 19.78 mm from the mental foramen toward the midline.13 The mental artery branches from the inferior alveolar artery inside the mandibular canal and exits the mandible through the mental foramen. It supplies the chin and anastomoses with its submental and inferior labial arter- ies12 . There are several anastomoses between the major arteries supply- ing the floor of the mouth and the sublingual region. This fact is im- portant because bleeding is more difficult to control whenever anas- tomoses are present. The following anastomoses have been document- ed in the literature: between the facial and the lingual arteries1,18, between the inferior alveolar artery and the submental artery, and be- tween the inferior alveolar artery and the sublingual artery through the lingual cortical plate15, and in close relationship with the lingual cortical plate in 54% of the cases14,22 . Recommendations for placement of implants in mandibular areas The sites with the highest risk of clinically important bleeding are the symphysis and the canine re- gion—these coincide with the lo- cations of the lingual canals, a fact that might help explain this bleed- ing6,1 . Moreover, the concavity in the symphysis may lead to perforation of the vestibular cortical plate if the implant is placed axially in the symphysis, whereas if an implant is placed tilted in the buccolingual direction, with the implant apex toward the lingual cortical plate, it can perforate the lingual cortical plate (Figs. 9a-9c). For this reason, implants should be placed slightly tilted toward the vestibular corti- cal plate, as shown in Figure 9c. The shape of the mandible in the poste- rior region is as shown in Figure 10, with a depression in the lingual cor- tical plate under the mylohyoid line. The depth of this submandibular fossa is greater than 2 mm (Figs. 10a & 10b) in 71.5-80.0% of patients23,24 . The presence of this fossa increases the risk of perforating the lingual cortical plate and of injuring the terminal branches of the sublingual artery during implant placement. However, in the posterior mandible, this risk is lower because the sub- lingual artery passes further from the lingual cortical plate25 . To our knowledge, only two cases of perfo- ration of the lingual cortical plate in the posterior mandible have been reported in the literature26 . Tilting of implants in the posterior man- dible is again a possible solution in order to avoid the submandibular fossa and maximize the use of the bone available in patients with bone atrophy in this region. Because the inferior alveolar nerve is closer to the mandibular lingual cortical bone27 and the alveolar crest height over the submandibular fossa may be limited, a novel approach has been proposed using implants tilt- ed in a buccolingual direction, tip- ping the implant apex toward the vestibule (Fig. 10)28 . Conventionally, longer implants have been used in the anterior mandible than in oth- er regions of the mandible or in the maxilla, owing to the lack of impor- tant anatomical structures such as the maxillary sinus or the inferior alveolar canal. Several authors have reported the appearance of sublin- gual hematomas after placement of dental implants of ≥ 15 mm in length in the anterior region of the mandible6,1 . This is the median dis- tance from the sublingual artery to the top of the alveolar ridge25 . The use of shorter dental implants may be advisable in the anterior region to reduce the risk of severe bleeding complications. > pagina 12 Fig. 6 - Location of the sublingual and submental arteries. (Modified from Kalpidis and Setayesh1 with permission from the American Academy of Periodontology.)