Influência de diferentes técnicas de cimentação de pinos de fibra de vidro na resistência à fratura, detecção de trincas e geração de artefatos em pré-molares unirradiculares

Abstract

Objectives: To evaluate the influence of different fiberglass post (FGP) cementation techniques on root fracture resistance, crack detection potential and generation of tomographic and microtomographic artifacts. Methodology: Forty single-rooted human premolars teeth were randomly divided into four groups (n=10): FGA- Fiberglass post cemented with dual-curing resin cement; FGCore- Fiberglass post cemented with dual-curing resin cement with high filler content; MCFG- Metal core fiberglass post cemented with dual- curing resin cement; AFG- Anatomical fiberglass post cemented with dual-curing resin cement. Each tooth was submitted to fracture resistance test at 0.5mm/min in a universal testing machine (ISTRON 3365 Machine). Then, all teeth were scanned on Skyscan 1172 to assess initial tooth morphology and fracture pattern using the following scores: (1) Fracture of the coronal composite resin; (2) Favorable root fracture; and (3) Unfavorable root fracture. In addition, a quantification of the percentage of artifacts generated in Computed Micro- Tomography (Micro-CT) images was performed. Cone-Beam Computed Tomography (CBCT) images were acquired using the CS 9000 3D (Kodak Dental Systems, Carestream Health, Rochester, NY, USA). Each tooth was scanned under four exposure parameters: 74kV, 80kV, 85kV and 90kV. The other parameters were set at 76 µm voxel size, 5 cm x 3.75 cm FOV size and 10 mA. Two observers assessed all CBCT images for root fracture detection using a 5-point confidence scale and a 4-point score for the presence of artifacts. One-way analysis of variance (ANOVA) and Tukey test were used to verify fracture resistance values between groups, while Fisher's exact test was used to verify the association between fracture pattern and groups. Quantitative evaluation of Micro-TC artifacts was analyzed using Kruskall Wallis and Mann Whitney tests. Sensitivity, specificity and area under the ROC curve (AUC) values were calculated and compared by two-way analyses of variance (ANOVA two-way) and Tukey's test Artifact interference on root fracture was assessed by chi-square test. Data were treated statistically at significance level of 5% ( α=0.05). Results: Fracture resistance values varied from 465,38 ± 127,29 N to 364,47 ± 78,64 N (p=0.159). No association between the fracture pattern and fiberglass cementation techniques was observed (p=0.276). The quantification of Micro-CT image artifacts for all groups presented less than 10% of artifacts (p=0,062). There were no significant differences between the exposure parameters for sensitivity, specificity and AUC values (p>0.05). AFG presented higher sensitivity values, statistically differing from FGCore and MCFG (p=0.037). MCFG specificity values differed statistically from FGCore (p=0.012). MCFG presented higher percentage of moderate artifacts than the other studied groups (p=0.001). Conclusions: Fiberglass cementation techniques did not influence the resistance, fracture pattern, and Micro-CT artifact intensity. Different exposure parameters do not seem to interfere on root fracture detection. The presence of a metal core fiberglass post decreases root fracture detection specificity values and increases artifact intensity in CBCT images.