RESUMO
OBJECTIVE: Simulation of tooth mobility in vitro with or without reduced bone support is an aspect of particular interest from the clinical perspective. To elucidate adequate simulation of the periodontal ligament in terms of tooth mobility, three materials were investigated. METHODS: Human lower sound premolars were selected and randomly assigned to six groups (n = 5) and stored at 37°C in a 0.5%-chloramine solution. For tooth mobility simulation, roots were covered with a thin layer of three types of material: (i) polyurethane elastomeric material, (ii) polyether impression material and (iii) A-polysiloxane soft cushion material. Teeth were embedded in an acrylic resin block simulating no and 50% bone loss, respectively. Specimens were statically subjected up to a maximum load of 30 N perpendicular to tooth axis (crosshead speed = 1 mm/min) in a universal material testing machine. Load-deflexion curves and periotest values were recorded. Statistical analysis was performed using 2-way Anova and post-hoc Bonferroni Test (p = 0.05). The Pearson's correlation coefficient between deflexion and periotest values was calculated. RESULTS: Median horizontal deflexion values (µm) of specimen crowns with no bone loss were significant higher for polysiloxane (210) compared to polyurethan (24) (p < 0.001). The tooth deflexion, e.g. tooth mobility, increased significantly as the bone level decreased only when specimens were embedded in polysiloxane (iii) (1150) (p = 0.045). All specimens with reduced bone support layered with polyether were dislocated. Deflexion was significantly positive correlated with periotest values (p = 0.01). CONCLUSION: Using A-polysiloxane soft cushion material combined with autopolymerizing acrylic resin may be suitable to simulate increased tooth mobility in vitro.