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Volume 2 | Issue 1/2016 37 Journal of Oral Science & Rehabilitation Rev iew of th e a rte r i al anato my i n the ante r i o r mandi ble counterpart on the opposite side and the sub- mental and inferior labial arteries.12 There are several anastomoses between the major arteries supplying the floor of the mouth and the sublingual region. This fact is important because bleeding is more difficult to control wheneveranastomoses are present.Thefollow- ing anastomoses have been documented in the literature: between the facial and the lingual ar- teries,1, 18 between the inferior alveolar artery andthe submentalartery, and betweenthe infe- rior alveolar artery and the sublingual artery through the lingual cortical plate,15 and in close relationshipwiththelingualcorticalplatein54% ofthecases.14,22 Recommenda tion s for pla c em en t of implants in m a n d ib ula r a rea s Thesiteswiththehighestriskofclinicallyimpor- tant bleeding are the symphysis and the canine region—these coincide with the locations of the lingual canals, a fact that might help explain this bleeding.6, 1 Moreover, the concavity in the sym- physis may lead to perforation of the vestibular corticalplateiftheimplantisplacedaxiallyinthe symphysis,whereas ifan implant is placedtilted in the buccolingual direction, with the implant apex toward the lingual cortical plate, it can per- forate the lingual cortical plate (Figs. 9a–c). For this reason, implants should be placed slightly tilted toward the vestibular cortical plate, as showninFigure9c.Theshapeofthemandiblein the posterior region is as shown in Figure 10, with a depression in the lingual cortical plate under the mylohyoid line. The depth of this submandibular fossa is greater than 2 mm (Figs. 10a & b) in 71.5–80.0% of patients.23, 24 The presence of this fossa increases the risk of perforatingthelingualcorticalplateandofinjur- ingtheterminalbranchesofthesublingualartery during implant placement. However, in the pos- terior mandible, this risk is lower because the sublingual arterypasses furtherfromthe lingual cortical plate.25 To our knowledge, only two casesofperforationofthelingualcorticalplatein theposteriormandiblehavebeenreportedinthe literature.26 Tilting of implants in the posterior mandible 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 inthis region. Becausethe inferioralveolarnerve isclosertothemandibularlingualcorticalbone27 and the alveolar crest height over the sub- mandibular fossa may be limited, a novel ap- proach has been proposed using implants tilted in a buccolingual direction, tipping the implant apextowardthevestibule(Fig. 10).28 Conventionally, longer implants have been used in the anterior mandible than in other re- gions of the mandible or in the maxilla, owing to thelackofimportantanatomicalstructuressuch as the maxillary sinus or the inferior alveolar canal.Severalauthorshavereportedtheappear- ance of sublingual hematomas after placement ofdentalimplantsof≥ 15 mminlengthinthean- terior region of the mandible.6, 1 This is the me- dian distance from the sublingual artery to the top of the alveolar ridge.25 The use of shorter dental implants may be advisable in the anterior regiontoreducetheriskofseverebleedingcom- plications. The use of 3-D imaging techniques and planning software may be useful to reduce the risk of bleeding complications. Correa et al. Figs. 9 a–c Correct angulation of the implant (c) to avoid perforation of the vestibular (a) or lingual (b) cortical plate in the anterior region of the mandible. B: buccal aspect; L: lingual aspect. Figs. 10 a & b Implant tilted (b) to avoid perforation of the lingual cortical plate (a) in the posterior region of the mandible when a deep submandibular fossa is present. L: lingual aspect; B: buccal aspect. Figs. 9 & 10 Volume 2 | Issue 1/201637