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

Eduardo Bortolas de Carvalho; Paulo Eduardo Herbst; Adriana Cláudia Lapria Faria; Ricardo Faria Ribeiro; Priscila Paganini Costa; Rodrigo Tiossi

doi:10.1016/j.prosdent.2017.03.017

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

J Prosthet Dent. 2018 Feb;119(2):250-256. doi: 10.1016/j.prosdent.2017.03.017. Epub 2017 May 23.

Authors

Eduardo Bortolas de Carvalho¹, Paulo Eduardo Herbst¹, Adriana Cláudia Lapria Faria², Ricardo Faria Ribeiro³, Priscila Paganini Costa⁴, Rodrigo Tiossi⁵

Affiliations

¹ Private practice, Latin American Institute for Dental Research and Education, Curitiba, Brazil.
² Post-doctoral Research Associate, Department of Dental Materials and Prosthodontics, University of São Paulo-Ribeirão Preto School of Dentistry, Ribeirão Preto, Brazil.
³ Professor, Department of Dental Materials and Prosthodontics, University of São Paulo-Ribeirão Preto School of Dentistry, Ribeirão Preto, Brazil.
⁴ Assistant Professor, Department of Oral Medicine and Pediatric Dentistry, School of Dentistry, State University of Londrina, Londrina, Brazil.
⁵ Assistant Professor, Department of Restorative Dentistry, School of Dentistry, State University of Londrina, Londrina, Brazil. Electronic address: rtiossi@uel.br.

PMID: 28545870
DOI: 10.1016/j.prosdent.2017.03.017

Abstract

Statement of problem: The 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.

Purpose: The purpose of this in vitro study was to test different planning options for replacing the mandibular first molar.

Material and methods: Two 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).

Results: The 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).

Conclusions: Two 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.

MeSH terms

Dental Implants, Single-Tooth*
Dental Stress Analysis
Humans
In Vitro Techniques
Models, Dental
Molar* / surgery