Immediate definitive individualized abutments reduce peri-implant bone loss: a randomized controlled split-mouth study on 16 patients.

OBJECTIVES: This paper aims to observe peri-implant time-related vertical bone level and soft tissue changes with immediate, non-detached glass-ceramic (lithium-disilicate) individualized abutments and dis-/reconnections. MATERIALS AND METHODS: Sixteen split-mouth patients received provisionalized immediate definitive individualized abutments (test T) versus dis-/reconnected individualized abutments (control C). In group T, digital impressions were made by using titanium bases (Conelog, Camlog), and individualized abutments (E.maxCAD) and temporary crowns (TelioCAD) were designed and milled (CerecMCXL). Lithium-disilicate abutments were crystallized and luted (Multilink Hybrid Abutment) to titanium bases. Non-occluding temporary crowns were connected to abutments. After 16 weeks, definitive digital restorations were delivered. In group C, 8 weeks were allowed after healing cap mounting for conventional impressions. Lithium-disilicate individualized abutments were produced, try-ins were performed by dis-/reconnections. Crowns were luted. Cone beam computed tomography (CBCT) images were obtained at restoration delivery, 12 months and 24 months. Pink esthetic scoring was made, plaque-gingival index measurements were done and statistical analyses (Shapiro-Wilk, Mann-Whitney U, Wilcoxon's, Spearman's rank, α = 0.05) were completed. RESULTS: No implant failures occurred. At 12 months, T (-0.1 ± 0.14 mm) exhibited significantly reduced vertical bone loss only on the labial side than C (-0.24 ± 0.13 mm) (p < 0.05). In T, all sides except distal presented reduced vertical bone loss at 24 months (p < 0.05). Vertical bone loss for all measurement sides in both C (-0.12 ± 0.09 mm; -0.18 ± 0.11 mm) and T (-0.17 ± 0.11; -0.26 ± 0.10 mm) was higher for 24 months than 12 months, respectively (p < 0.05). CONCLUSIONS: Reduced vertical bone loss was observed around implants with immediate definitive individualized abutments than abutments with repeated dis-/reconnections. CLINICAL RELEVANCE: Non-detached immediate definitive lithium-disilicate individualized abutments and provisionalization through digital technology resulted in successful clinical outcomes and can be routinely applied.

Microshear bond strength and finite element analysis of resin composite adhesion to press-on-metal ceramic for repair actions after various conditioning methods.

PURPOSE: This study evaluated the repair bond strength of differently surface-conditioned press-on-metal ceramic to repair composites and determined the location of the accumulated stresses by finite element analysis. MATERIALS AND METHODS: Press-on-metal ceramic disks (IPS InLine PoM, Ivoclar Vivadent) (N = 45, diameter: 3 mm, height: 2 mm) were randomly divided into 3 groups (n = 15 per group) and conditioned with one of the following methods: 9.5% hydrofluoric acid (HF) (Porcelain etch), tribochemical silica coating (TS) (CoJet), and an unconditioned group acted as the control (C). Each group was divided into three subgroups depending on the repair composite resins: a) Arabesk Top (V, a microhybrid; VOCO), b) Filtek Z250 (F, a hybrid;3M ESPE); c) Tetric EvoCeram (T, a nanohybrid; Ivoclar Vivadent) (n = 5 per subgroup). Repair composites disks (diameter: 1 mm, height: 1 mm) were photopolymerized on each ceramic block. Microshear bond strength (MSB) tests were performed (1 mm/min) and the obtained data were statistically analyzed using 2-way ANOVA and Tukey's post-hoc test (α = 0.05). Failure types were analyzed under SEM. Vickers indentation hardness, Young's modulus, and finite element analysis (FEA) were performed complementary to MSB tests to determine stress accumulation areas. RESULTS: MSB results were significantly affected by the surface conditioning methods (p = 0.0001), whereas the repair composite types did not show a significant effect (p = 0.108). The interaction terms between the repair composite and surface conditioning method were also statistically significant (p = 0.0001). The lowest MSB values (MPa ± SD) were obtained in the control group (V = 4 ± 0.8; F = 3.9 ± 0.7; T = 4.1 ± 0.7) (p < 0.05). While the group treated with T composite resulted in significantly lower MSB values for the HF group (T= 4.1 ± 0.8) compared to those of other composites (V = 8.1 ± 2.6; F = 7.6 ± 2.2) (p < 0.05), there were no significant differences when TS was used as a conditioning method (V = 5 ± 1.7; F = 4.7 ± 1; T = 6.2 ± 0.8) (p > 0.05). The control group presented exclusively adhesive failures. Cohesive failures in composite followed by mixed failure types were more common in HF and TS conditioned groups. Elasticity modulus of the composites were 22.9, 12.09, and 10.41 GPa for F, T, and V, respectively. Vickers hardness of the composites were 223, 232, and 375 HV for V, T, and F, respectively. Von Mises stresses in the FEA analysis for the V and T composites spread over a large area due to the low elastic modulus of the composite, whereas the F composite material accumulated more stresses at the bonded interface. CONCLUSION: Press-on-metal ceramic could best be repaired using tribochemical silica coating followed by silanization, regardless of the repair composite type in combination with their corresponding adhesive resins, providing that no cohesive ceramic failure was observed.

Fatigue and Stress Distribution Analyses of Ceramic-Reinforced PEEK Abutments Restored with Monolithic Zirconia Crowns as an Alternative to Conventional Esthetic Abutments.

PURPOSE: To determine the fracture strength and stress distribution of esthetic dental implant abutments. MATERIALS AND METHODS: Fifty specimens were prepared. Four hybrid abutment groups with titanium bases (zirconia [Z], lithium disilicate [L], ceramic-reinforced polymer [B] and [BC]) and a custom titanium abutment control group (T) were restored with monolithic zirconia crowns except BC, which was crowned with layered composite. Ceramic abutments were cemented on Ti bases with a self-curing resin cement. Polymer abutments were cemented on Ti bases with an adhesive resin cement. All crowns for T, Z, and L were cemented with another self-adhesive resin cement, while the B and BC groups were cemented with the same adhesive resin cement for the polymer. Fatigue testing was performed by a chewing simulator (CS-4.2, SD, 50 N, 240,000 cycles) followed by fracture strength testing (0.5 mm/min, 5,000 N). Failure type analysis was made by a stereomicroscope. Statistical analyses were made (SPSS 25.0, analysis of variance [ANOVA], Tukey honestly significant difference [HSD], 95% CI). Complementary finite element analyses (FEAs) were performed (Algor Fempro). RESULTS: Mean ± SD fracture strengths for T, Z, L, B, and BC were 1,522.67 ± 190.77, 1,207.76 ± 89.03, 818.81 ± 109.96, 1,126.23 ± 142.23, and 899.08 ± 60.36, respectively (P < .05). Abutment screw flexure and/or cracks or crown material fractures for T, Z, L, and B occurred, while no implant and/or abutment fractures were observed for BC except for crown fracture and Ti base flexure. FEA exhibited similar stress concentrations. CONCLUSION: Monolithic zirconia crowns on titanium abutments and hybrid zirconia abutments exhibited the highest fracture strengths. Lithium disilicate and BioHPP abutments had the lowest fracture strength, while no fractures were observed on the implant, abutment, or screw.

Replacement of maxillary lateral incisors with digitally manufactured single tooth retained all-ceramic pontics: a clinical report / Reabilitação da região de incisivo lateral superior ausente por pôntico modelo cantiléver em cerâmica pura fabricado digitalmente: relato de caso clínico

Several treatment options for replacement of anterior missing teeth exist, varying from no-prep (no preparation) adhesive restorations to implants. Patients' biological, psychological, economic conditions or age have an effect on the treatment choice. It is important to perform the most conservative and beneficial treatment option considering the patient based factors. The aim of this case report was to demonstrate a single session, minimally invasive, cantilevered 2-unit all-ceramic restorations replacing anterior missing teeth combined with the advantages of CAD/CAM technology and materials. (AU)

Existem várias opções de tratamento para reabilitação de dentes anteriores ausentes, variando de restaurações adesivas sem preparo (sem preparação) até implantes. As condições biológicas, psicológicas, econômicas ou a idade dos pacientes têm um efeito na escolha do tratamento. É importante realizar a opção de tratamento mais conservadora e benéfica, considerando os fatores baseados no paciente. O objetivo deste relato de caso foi demonstrar em sessão única, minimamente invasiva, um cantiléver de restaurações de cerâmica pura de 2 unidades, reabilitando a região de dentes anteriores ausentes combinadas com as vantagens da tecnologia CAD/CAM.(AU)

A customized zirconia abutment design combined with a CAD/CAM laminate veneer: a clinical report.

An alternative prosthetic treatment approach for single implants in the maxillary esthetic zone with an improper implant axis, limited interocclusal distance, inadequate abutment retention, and screw holes located at the labial surface is presented in this clinical report. The gingiva and soft tissues were contoured with provisional composite restorations to mimic the emergence profile of lateral incisors. Prefabricated zirconia abutments were customized with laminate veneer preparations by appropriate ceramic build-up with reference from the reshaped gingiva to avoid labiolingual overcontour. The laminate veneers were fabricated by computer-aided design/ computer-assisted manufacture to cover the screw hole of the angulated abutment at the labial surface. Preliminary results revealed improvement in esthetics; however, long-term clinical follow-up should be performed.

Influence of surface treatment on the resin-bonding of zirconia.

OBJECTIVE: To compare the effect of various surface treatments on the bonding of luting resin cements to zirconia under four-point bending. METHODS: Bar specimens (n = 200) (2 mm × 5 mm × 25 mm) were prepared from zirconia blocks (VITA In-Ceram YZ, Vita Zahnfabrik) with the cementation surface (2 mm × 5 mm) of groups of 40 treated in one of five ways: airborne particle abrasion with 50µm Al2O3 (GB), zirconia primer (Z-Prime Plus, Bisco) (Z), glaze ceramic (Crystall.Glaze spray, Ivoclar Vivadent) + hydrofluoric acid (GHF), fusion glass-ceramic (Crystall.Connect, Ivoclar Vivadent) (CC), or left untreated as control (C). Within each treatment, bars were cleaned ultrasonically for 15 min in ethanol and then deionized water before bonding in pairs with one of two luting resins: Panavia F 2.0, (Kuraray) (P); RelyX U-200 (3M/Espe) (R), to form 10 test specimens for each treatment and lute combination. Mechanical tests were performed and bond strengths (MPa) were subject, after log transformation, to analysis of variance, Shapiro-Wilk and Holm-Sidak tests; also log-linear contingency analysis of failure mode distribution; all with α = 0.05. Fracture surfaces were examined under light and scanning electron microscopy. RESULTS: While the effect of surface treatment was significant (p = 1.27 × 10(-9)), there was no detected effect due to resin (p = 0.829). All treatments except CC (30.1 MPa ×/÷ 1.44)* were significantly better than the untreated control (24.8 MPa ×/÷ 1.35) (p = 3.28 × 10(-9)). While the effect of GB - which gave the highest mean strength (50.5 MPa ×/÷ 1.29) - was not distinguishable from that of GHF (39.9 MPa ×/÷ 1.29) (p = 0.082), it was significantly better than treatment with either CC or Z (33.1 MPa ×/÷ 1.48) (p < 0.05). (* After log transformation for analysis and back; asymmetric error bounds as s.d. in log values.) SIGNIFICANCE: The novel test method design, which has good discriminatory power, confirmed the value of gritblasting as a simple and effective treatment with low operator hazard. It gave the highest bond strengths regardless of the cement type. Glaze layer application followed by hydrofluoric acid-etching on zirconia before cementation might be viable for adhesive zirconia cementation, but represents a much greater hazard as well as having problems with thickness control.