Within the limitations of this study, fabrication method, whether CAD/CAM or heat-pressed, had no effect on the marginal and internal adaptation of porcelain laminate veneers. The results showed that both fabrication techniques performed well after 2 years of clinical performance.

Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques.Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (p<0.05), before and after cementation.Results Direct inlays presented statistically smaller marginal discrepancy values than indirect inlays, before (p=0.00001442) and after (p=0.00001466) cementation. Marginal discrepancy values were increased for all restorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner.Conclusions Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation.

PURPOSETo determine whether the fracture strengths and failure types differed between metal and zirconia frameworks veneered with pressable or layering ceramics.MATERIALS AND METHODSA phantom molar tooth was prepared and duplicated in 40 cobalt-chromium abutments. Twenty metal (IPS d.SIGN 15, Ivoclar, Vivadent, Schaan, Liechtenstein) and 20 zirconia (IPS e.max ZirCAD, Ivoclar) frameworks were fabricated on the abutments. Each framework group was randomly divided into 2 subgroups according to the veneering material: pressable and layering ceramics (n=10). Forty molar crowns were fabricated, cemented onto the corresponding abutments and then thermocycled (5-55℃, 10,000 cycles). A load was applied in a universal testing machine until a fracture occurred on the crowns. In addition, failure types were examined using a stereomicroscope. Fracture load data were analyzed using one-way ANOVA and Tukey HSD post-hoc tests at a significance level of 0.05.RESULTSThe highest strength value was seen in metal-pressable (MP) group, whereas zirconia-pressable (ZP) group exhibited the lowest one. Moreover, group MP showed significantly higher fracture loads than group ZP (P=.015) and zirconia-layering (ZL) (P=.038) group. No significant difference in fracture strength was detected between groups MP and ML, and groups ZP and ZL (P>.05). Predominant fracture types were cohesive for metal groups and adhesive for zirconia groups.CONCLUSIONFracture strength of a restoration with a metal or a zirconia framework was independent of the veneering techniques. However, the pressing technique over metal frameworks resisted significantly higher fracture loads than zirconia frameworks.

A limited opening of the mouth is defined as microstomia. Microstomia is caused by burns, postoperative head and neck trauma, radiotherapy, or scleroderma. The prosthetic treatment of microstomia presents particular challenges, and patients often complain of an inability to insert or remove the prosthesis. The cause and severity of microstomia can influence the approach to treatment. Different treatment methods have been suggested, including the fabrication of two-piece partial dentures. This clinical report describes the construction of a sectional impression tray and a collapsed partial denture using a hinge attachment for a patient with microstomia.

Marginal bone level is a criterion for implant success. The aetiological factors of bone loss have not been clarified. The aim of this study was to evaluate the influence of implant systems and prosthetic materials on the marginal bone loss. Twenty-three patients participated; two implant systems and three superstructure materials were used in this study. Twenty-two of the implants were restored with porcelain fused to base metal alloy (BMA), 25 with porcelain fused to noble metal alloy (NMA) and 20 with zirconium oxide-based ceramics. Radiographs were taken at baseline and 3, 6 and 12 months after loading. Crestal bone-level changes were assessed with digital subtraction radiographs. The effects of superstructure materials and implants were evaluated with one-way anova and independent samples t-test, respectively (α = 0·05). The mean crestal bone loss was found 0·483 mm in 3 months, 0·622 mm in 6 months and 0·816 mm in 12 months. Prosthetic materials were found to have greater effect (β = 0·575, P = 0·015) on crestal bone loss than implant systems (P > 0·05). The porcelain fused to BMA restorations showed higher crestal bone loss than NMA-based restorations (P = 0·003) at 3 months, (P = 0·038), at 6 months and (P = 0·00) at 12 months; however, crestal bone loss differences between NMA and zirconia were not significant (P = 0·629) at 3 months, (P = 0·974) at 6 months and (P = 1) at 12 months. Within the limitations of this study, our results revealed that rather than the implant systems, prosthetic materials seemed to have an effective role on crestal bone.

A B S T R A C TObjectives: The aim of the study was to evaluate and compared the effects of 2 different tooth preparation designs on the stress distribution in tooth, cement, core and two ceramic layers of all ceramic anterior crown using the 3 Dimensional (3D) Finite-Element-Analysis (FEA) method. Anterior tooth-crown configuration composed of both layers of restoration is lacking.Materials and Methods: 1 mm circumferential shoulder and chamfer finish line preparations were performed with rounded shoulder and chamfer diamond cylindrical burs with rounded angles on 2 maxillary central teeth. 1 mm thickness of the frameworks were (IPS e.max Press, Ivoclar-Vivadent, Schaan, Liechtenstein) prepared by pressing technique. After scanning the frameworks for FEA, dentin and enamel ceramics (IPS e.max Ceram, Ivoclar-Vivadent) were applied. Each ceramic layer was scanned for finite-element models. The Variolink II (IvoclarVivadent) was used as a luting material and modeled. A 200 N static load was applied at 45° to the palatal surface. 3D-FEA was performed with I-DEAS software.Results: Rounded-shoulder model showed higher Von Mises stress values in prepared tooth, core, resin cement, and both two layers of the ceramic than chamfer model. Roundedshoulder preparation type within all evaluated models had more dispersed stress distribution localization areas than chamfer preparation type's models. The highest Von-Mises stress values were found within the first ceramic layer of the shoulder model (26.5 MPa) on 1/3 of the buccal surface. Low stress values were found at dentin tooth structures for both chamfer and rounded-shoulder models.Conclusions: Rounded-shoulder preparation type showed higher Von-Mises stress values at both layers of crown. Minimum Von-Mises stress values were found at dentin regardless of the preparation type.

In geriatric patients, the shear bond strength of glass-ceramics did not differ when compared to that of young controls. On the dentin surface, etch-rinse resin cements appear to be more appropriate for glass-ceramics bonding.

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