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Background: The aim of this study was to evaluate the effect of horizontal and vertical tooth preparation on the internal and marginal fit of zirconia reinforced lithium silicate and monolithic zirconia fixed partial dentures.Methods: Forty ceramic fixed partial dentures were divided into four groups (n=10) according to ceramic type and finish line design. Group HL: Horizontal tooth preparation with heat pressed zirconia reinforced lithium disilicate. Group HZ: Horizontal tooth preparation with zirconia fixed partial denture. Group VL: Vertical tooth preparation with heat pressed zirconia reinforced lithium disilicate fixed partial denture. Group: VZ: Vertical tooth preparation with zirconia fixed partial denture. Micro-CT was used to evaluate the fit of each fixed partial denture. Data were collected and statistically analyzed.Results: Horizontal preparation showed a significant better fit than that of vertical preparation for both abutments (P˂.001). Zirconia showed significant better fit than heat pressed zirconia reinforced lithium disilicate for the posterior abutment. All the results were within internal and marginal fit requirements.Conclusions: Nevertheless, being within the clinically acceptable fit values, the vertical preparation can negatively affect the marginal gap and internal fit of fixed partial dentures at certain points. The marginal gap and internal fit of the ceramic fixed partial dentures can be affected by ceramic type and finish line design.

The purpose of this study was to establish a new mouse model of endometriosis that mimics real-world women’s health problems, in which women continue to be affected by endometriosis long before they wish to become pregnant, and to evaluate the impact of “chronic exposure to endometriosis” on perinatal outcome. Endometriosis was established by the intraperitoneal injection of homologous minced mouse uteri. Vehicle was injected for the control. Mating was initiated either 1 or 43 days after disease establishment (Young or Aged studies, respectively). Mice were sacrificed on 18 dpc. The number pups and resorptions were counted and pups’ body weights (BW) were measured, and the endometriosis lesion was identified and weighted. In the Young study, the number of resorptions and BW were comparable between the groups. In the Aged study, the number of resorptions was significantly higher and BW was significantly lower in endometriosis than that in control. The total weight of endometriosis lesion per dam was significantly lower in the Aged compared to the Young endometriosis group; however, not a single mouse was found to have any lesions at all. These results suggest that in addition to the presence of endometriosis per se, “chronic exposure to endometriosis” prior to pregnancy affect perinatal outcomes.

Purpose To evaluate the effect of finish line design (chamfer and feather‐edge) and ceramic type on the internal and marginal fits of fixed partial dentures on abutment teeth. Materials and methods Two typodont mandibular casts, missing right first premolar tooth, received tooth preparation on canine and second premolar abutments (one cast with chamfer finish line and the other cast with feather‐edge finish line). The preparation segment of each typodont model was scanned, 3D printed in resin, and then invested and casted in metal to obtain two metal models. Polyvinyl siloxane impressions were made for the metal models and poured in type IV stone. The stone models (n = 40) were randomly assigned into four groups (n = 10): chamfer finish line with heat‐pressed zirconia reinforced lithium disilicate fixed partial denture (CL), chamfer finish line with monolithic zirconia fixed partial denture (CZ), feather‐edge finish line with heat‐pressed zirconia‐reinforced lithium disilicate fixed partial denture (FL), and feather‐edge finish line with monolithic zirconia fixed partial denture (FZ). After the fabrication of ceramic restoration, micro‐computed tomography was used to evaluate the internal and marginal fits of each fixed partial denture. Data were statistically analyzed with three‐way ANOVA (α = 0.05). Results There were no significant interactions between preparation type, material type, and tooth type at any of the areas assessed. There was significant difference (p = 0.01) between CZ (59.15 ± 4.6 µm) and FZ (73.6 ± 17.1 µm) groups at the finish line area. Regarding the horizontal marginal discrepancy area, there were significant differences between CZ (62.65 ± 10.5 µm) and FZ (90.05 ± 5.6 µm) groups (p < 0.001), CL (77.45 ± 8.1 µm) and CZ (62.65 ± 10.5 µm) groups (p < 0.001), and FZ (90.05 ± 5.6 µm) and CL (77.45 ± 8.1 µm) groups (p < 0.001). At finish line area, there was a significant difference (p = 0.018) between feather‐edge with canine (72.75 ± 13.3 µm) and chamfer with canine (59.05 ± 5.8 µm); however, there was no significant difference (p = 0.774) between feather‐edge with premolar (69.45 ± 12 µm) and chamfer with premolar (65.1 ± 7.4 µm). Moreover, there was no significant difference (p = 0.886) between feather‐edge with canine and feather‐edge with premolar. Conclusions The internal and marginal fits of the ceramic fixed partial dentures can be affected by the finish line design and ceramic type. The feather‐edge finish line had a negative impact on the marginal and internal fits of ceramic fixed partial dentures at certain measurement points. Regarding the effect of finish line design on abutment teeth, the difference in fit was only detected at the finish line area of the anterior abutment (canine) with the feather‐edge finish line.