StomatologyEduJournal1-2015 | Page 72

ORAL REHABILITATION Table 3 Sinus complications in studies in which zygomatic implants were placed using the two-stage protocol Two-stage protocol Patients (n) Follow-up period (months) Survival rate of zygomatic implants % Sinusitis % Malevez et al.(2004) 55 6-48 100 5 (9) Hirsch et al.(2004) 76 12 98 3 (4) Becktor et al.(2005) 16 9-69 90.3 6 (26.6) Farzad et al.(2006) 11 18-56 100 1 (9.1) Davo et al.(2009) (53) 24 60 97.4 5 (20.8) Stièvenart et al.(2010) (54) 10 (of 20) 40 96.3 1 (1.3) Aparicio et al.(2012) 22 120 97.7 2 (9.1) Table 4 Sinus complications in studies in which zygomatic implants were placed using the immediate function protocol Immediate function protocol Total number of patients Follow-up period (months) Survival rate of zygomatic implants % Sinusitis % Aparicio et al. (2004) 20 6-48 100 0 Mozzati et al. (2008) 7 24 100 0 Outcomes The severely atrophied maxilla constitues a therapeutic problem for a restorative dentist, especially when previously performed rehabilitations result in failure and patients’ dissatisfaction. The zygomatic implants were introduced to solve prosthetic reconstruction problems in fully edentulous patients. The zygomatic implant is a titanium endosteal implant ranging from 30 mm to 52.5 mm in length. The apical two thirds of the implant is 4 mm in diameter and the alveolar one third is 5 mm in diameter. The surgical technique for inserting zygomatic implants has been the subject of modification during the last years, with today essentially two major vari ations existing: the internal and the external approach. In the first option, the sinus membrane is carefully dissected and the implant is inserted internal to the maxillary sinus as reported by Brånemark and colleagues (31). The extrasinusal technique is characterized by inserting the implant external to the maxillary sinus before anchoring in the zygomatic bone. In this case the implant is covered only by soft tissue along its lateral maxillary surface. The decision for an “external” rather than an “internal” placement 72 of the zygomatic implant must be the result of accurate anatomic assessments. For this reason Aparicio et al. (32) proposed a classification for zygomatic implant patient based on the zygoma anatomy guided approach: the ZAGA approach. It is a modification of the original zygomatic implant technique and it focuses on interindividual anatomic differences. Thus, the path of the implant body can vary from being totally intrasinus to being totally extrasinus, depending on the relationship between the different anatomic components. Keller et al. (10) and Branemark et al. (31) suggested that zygomatic implants may be used as an alternative to bone grafts in case of severe maxillary resorption, because the insertion of these implants does not require additional surgery. This major surgical technique requires a proper training and many studies were conducted in an institutional environment, such universities or specialty clinics. The presurgical protocols provide for the selection and preparation of patients in order to allow promising results. Once the clinical examination is complete, radiographic examinations are performed to ensure appropriate treatment planning of the zygomatic implants. The presurgical exams recommended are following: STOMA.EDUJ (2015) 2 (1)