Retrospective analysis of the predictability of using prototypes for pre-operative planning of the length of zygomatic implants

• Grant number: 19/17290-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2019
• Effective date (End): October 31, 2020
• Field of knowledge: Health Sciences - Dentistry - Oral and Maxillofacial Surgery
• Principal Investigator: Alexandre Elias Trivellato
• Grantee: Thales Fabro Vanzela Sverzut
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Maxilla in advanced stages of bone loss present significant decrease of bone volume, making their functional rehabilitation all the more difficult. The reason for that is the lack of sufficient bone volume for the installation osseointegrated dental implants, or for the retention of conventional dental prosthesis. Reconstructive preprosthetic surgeries such as: bone grafts and/or the use of biomaterials, Le Fort I osteotomy with interpositional bone graft, and maxillary sinus lift are ways around this issue. The success rates of such techniques are good, but they require long and invasive surgical procedures, the bone graft can be contaminated or exposed, and the complete rehabilitation takes months. Zygomatic implants are an alternative to such procedures. However, the installation of zygomatic implants requires preoperative planning and its surgical technique is more complex than that of conventional implants. That's mostly due to the meager bone volume present in the maxilla, and the length and trajectory of the zygomatic implants. This present study aims to retrospectively evaluate if the use of prototypes obtained from the tridimensional printing of computed tomography scans is a reliable and predictable method of planning the lengths of zygomatic implants. The records of every patient that received zygomatic implants through the Ribeirão Preto School of Dentistry's Oral and Maxillofacial Surgery residency program, from the period between March/2007 and March/2019, will be evaluated and studied. These records will be separated, and the expected length of the zygomatic implants on the prototypes will be compared to the length of the implants the patients received. All this information is written down on a record specific to this type of treatment. Data such as age, gender, bone loss classification according to Cawood; Howell, and state of health according to the American Society of Anesthesiologists' classification will also be collected. All data will be registered on Microsoft Excel for statistical analysis. The results will be put through the Mann-Whitney U test, or Student's t test, if they are nonparametric or parametric, respectively.