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Volume 2 | Issue 1/2016 43 Journal of Oral Science & Rehabilitation Tra n s c res ta l s in us f lo o r e le vati o n wi th a so ni c i nstru me nt the sinusfloorranged between 2 mm and 4 mm, dependingontheoutlineofthebaseofthesinus. Itwasnotpossibletoguaranteeimplantprimary stability; thus, a two-stage approach was fol- lowed (Figs. 1a–c). Micro-cone beam computed tomography (CBCT) scans (Kodak 9000, Care- stream Health, Rochester, N.Y., U.S.) were taken beforesurgery. First stage of s in us floor eleva tion A split-thickness flap was dissected using a scalpel blade (BD Beaver 376400, BD Medical Ophthalmic Systems, Waltham, Mass., U.S.). A longitudinal incision was performed on the alveolar crest 3–4 mm palatal to the center of the crest. Short paramarginal releasing inci- sions were performed mesially (Fig. 2a). The dissection of the flap at the buccal aspect was extended uptothe mucogingivaljunction, leav- ing only a thin layer of connective tissue on the bone surface in order to better visualize the bony crest morphology. After flap elevation, a bone trapdoor was prepared with the use of a vibrating sonic handpiece (Sonosurgery, TeKne Dental, Calenzano, Italy) into which a straight micro-saw (SFS 102, Komet Dental Gebr. Bras- seler, Lemgo, Germany) had been inserted. The trapdoorwasproducedinthecenterofthealve- olar crest and was < 2.5 mm wide in the bucco- lingualplane.Theboneincisionwasextendedin amesiodistaldirectionfortheentireedentulous area to be treated. However, a safe distance of about 1.5 mm from the premolar was main- tained to avoid damaging the root (Figs. 2b–f). The osteotomy of the bone trapdoor was performedwithamicro-saw0.25 mmthickand exercising minimal pressure, similar to that of a pencil when writing (a maximum of 2–3 N). These incisions on the bone were performed with an external bevel, so that the bone trap- door had a trapezoidal cross-section, the largest base being at the cranial and the small- est at the caudal aspect of the trapdoor. A con- tinuousmovementalongtheincisionshadtobe carried out by the operator using the sonic in- sert, graduallypenetrating intothe bone, untila distinct change of material texture was per- ceived, indicating that the base ofthe sinus had been reached. After that, the trapdoor was re- leased along the osteotomies using a surgical mallet on blunt chisels (KLS Martin Group, Umkirch, Germany) with gentle taps (Fig. 3a). Collagen sponges (Gingistat, GABA VEBAS, Rome, Italy) were placed into the space ob- tained in order to prevent the Schneiderian membranefromtearing, andthesewere subse- quently pushed within the subantral space us- ing the blunt chisels and mallet (Figs. 3b & c). The 3-D hydraulic pressure produced by the collagen soaked with blood encouraged the sinus membrane detachment from the bone walls. After sinus elevation, the buccal flap was repositioned and sutured to the palatal aspect, allowing a primary intention wound closure. A CBCT scan with a low radiation dose was taken immediately after the surgery (Figs. 4a–c). Intra-oral radiographs were taken one, two and three months after the first sinus elevation (Figs. 5a–c). Se co nd stage o f si nu s f lo o r e le vati o n Four months after the first surgical session, an intra-oral radiograph was taken and assessed (Fig. 5d). The radiographs showed that the base of the sinus had gained about 3–4 mm in height compared with the original situation, yielding a total height of about 5–6 mm, which could allow for primary implant stability. No clinical signs ofinflammationwere observed.A surgical procedure similar to that used in the first stage was performed, including the mu- cosal incision. Again, a buccolingual crestal os- teotomy< 2.5 mmwidewasmade(Figs. 6a&b). Theaugmenteddimensionsofthesinusfloor compared with the initial situation allowed the execution ofdeeperosteotomieswith more pro- nouncedbevelsthanthosecarriedoutduringthe previous surgical stage. Consequently, the bone trapdoor was higher and wider in the cranial regions in comparison with that prepared in the firstsurgicalstage. Chisels of increasing thickness were used to distractthe bonetowardthe sinus,following the incisions made with the sonic micro-saw. This, inturn, meantthatthe chisels had awork- ing direction with the same angulation as the osteotomies. Once the trapdoor had been split and mobilized by blunt chisels and a mallet, both buccally and palatally from the parent bone, collagen sponges were added and an im- plant with a conical shape (Pilot, Sweden & Martina, Due Carrare, Italy) was placed (Fig. 6c).The implant apex pushedthe collagen and the bone further, producing an additional sinus floor elevation. Implant primary stability was obtained by means of the pressure of the Figs. 1a–c First sinus floor elevation stage in the three planes. In the initial CBCT scan, a fracture of the second molar and a periapical radiolucency were observed. The insufficient sinus floor height in the first molar position did not allow for immediate implant placement. (a) Panoramic view. (b) Cross-sectional view. (c) Axial view. Figs. 2a–f Clinical view of the surgical procedures. (a) Site after flap dissection and extraction of the first molar. The osteotomies were performed with an external bevel using a micro-saw 0.25 mm thick and exercising minimal pressure. The bevel cuts were orientated (b) mesially, (c) palatally, (d) distally, and (e) buccally, respectively. (f) The osteotomies of the trapdoor were finalized. Figs. 3a–c (a) The elevation of the trapdoor and of the sinus floor was performed with a surgical mallet on blunt chisels. (b) Collagen sponges were placed into the space obtained, and these were subsequently pushed within the subantral space using the blunt chisels and mallet. (c) Situation after the placement of collagen sponges. Figs. 4a–c A CBCT scan was taken immediately after the surgery. (a) Panoramic view. (b) Cross-sectional view. (c) Axial view. Volume 2 | Issue 1/201643