Strain transfer behavior of different planning options for mandibular single-molar replacement

Publication date: Available online 23 May 2017
Source:The Journal of Prosthetic Dentistry
Author(s): Eduardo Bortolas de Carvalho, Paulo Eduardo Herbst, Adriana Cláudia Lapria Faria, Ricardo Faria Ribeiro, Priscila Paganini Costa, Rodrigo Tiossi
Statement of problemThe loss of the first molar and second premolar could lead to mesial movement of the second molar, thus limiting the restoration space for the 2 missing teeth. Placement of a larger first molar is a common choice, but the best implant number and position option remain controversial.PurposeThe purpose of this in vitro study was to test different planning options for replacing the mandibular first molar.Material and methodsTwo polyoxymethylene models simulated first molar edentulous spaces of 11 mm (conventional size first molar: control group) and 14 mm (enlarged first molar: all remaining groups other than control). Models included acrylic resin replicas of a first and second premolar, a second molar, and the first molar edentulous space. The following groups were established: control (CO), ø3.5-mm center implant; center implant (CI), ø3.5 mm; mesial implant (MI), ø3.5 mm; distal implant (DI), ø3.5 mm; center implant (WI), ø5.0; 2 implants (2I), 2 ø3.5-mm implants. Three Co-Cr molar crowns were fabricated for each group by using a computer-aided design and computer-aided manufacturing (CAD-CAM) technique. Model surface strains under a 250-N first molar load were calculated by 3-dimensional digital image correlation. Three regions of interest below the first molar were selected for comparison among groups. A test for unequal variances and a follow-up Welch ANOVA were used for statistical analysis (α=.05).ResultsThe highest strains were found when the first molar was restored by using a 5.0-mm-wide implant (P<.05). Region of interest 1 showed that two 3.5-mm implants replacing the lost molar showed strain distribution similar to that of only one 3.5-mm implant (P>.05). Mesial and distal placement of the implant showed more neutral strain results than other restoration options (P<.05).ConclusionsTwo small-diameter implants in an increased edentulous space show more optimized surface strain behavior than a single wide-diameter implant. However, a single 3.5-mm implant also showed reduced strains in the restoration of the same edentulous space.



http://ift.tt/2qdq9NM