Years Of Clinical Service Research Articles

Retentive force of PEEK secondary crowns on zirconia primary crowns over time.

The purpose of the present study was to evaluate the retentive forces of CAD/CAM-fabricated polyetheretherketone (PEEK) secondary crowns on zirconia primary crowns over an artificial aging period representing 10years of clinical service and compare them to electroformed secondary crowns made from pure gold. Implant-supported zirconia primary crowns (N = 20) were CAD/CAM milled and provided either with electroformed secondary crowns (group ZE; N = 10) or CAD/CAM-fabricated PEEK secondary crowns (group ZP; N = 10). All secondary crowns were attached to a casted tertiary structure to ensure adequate stability. A universal testing machine was used to determine the retentive force values at baseline and after 1, 3, 5, and 10years of simulated aging in the presence of artificial saliva. Data were analyzed applying Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U test. Level of significance was set at p < 0.05. Retentive forces were not different for the groups ZE and ZP at baseline (median ZE 2.85N; ZP 2.8N; p ≤ 0.218). Because retentive force values changed significantly over simulation time for group ZE (Kruskal-Wallis; p ≤ 0.028), the values between the test groups ZE and ZP differed significantly (Mann-Whitney U) at 5years (ZE 3.03N; ZP 2.76N; p ≤ 0.003) and 10years (ZE 3.1N; ZP 2.78N; p ≤ 0.011). PEEK secondary crowns exhibit stable retentive force values over 10years of simulated aging showing no signs of deterioration while the retentive force values of electroformed secondary crowns increase over time. PEEK might be a suitable alternative to proven metallic materials for the fabrication of secondary crowns.

Clinical evaluation of screw retained monolithic crowns with titanium resin based abutments

Background There is limited data available on the survival of monolithic zirconia single crowns with titanium resin based abutments. Aim/Hypothesis The aim of this follow-up case series was to evaluate the prosthetic maintenance of screw retained posterior monolithic zirconia crowns after 1 to 3 years of clinical service. Material and Methods Nineteen patients who had received a single implant in the posterior region were included. Titanium resin based abutments were used to fabricate monolithic zirconia crowns. After try in, crowns were cemented onto the abutments with resin cements in the laboratory. Peri-implant parameters, mechanical and biologic complications and patient satisfaction parameters were recorded at baseline and all follow-up examinations. Results A total of 35 monolithic zirconia crowns (22 molar and 13 premolar) were examined. None of the patients had neither screw-loosening nor decementation. Parallel periapical examination revealed a marginal bone loss less than 0.5 mm. Peri-implant parameters gingival index, plaque index, and gingival bleeding time index scores were generally lower in all crowns indicating peri-implant health situation. Conclusions and Clinical Implications Screw retained monolithic zirconia crowns based on titanium based resin abutments were promising treatment option on single implant restorations.

EVALUATION OF SHEAR BOND STRENGTH OF HIGH-PERFORMANCE POLYMERS TO ITS RESIN VENEERING AND TO DENTIN (IN VITRO STUDY)

INTRODUCTION: : Looking through the wide range of prosthetic options High-performance polymers properties. Needs over layering resin veneer, bonded by a special adhesive, this adds an additional challenge to achieve adequate bond strength, also its bonding to tooth structure remains difficult. OBJECTIVES: To evaluate shear bond strength of CAD/CAM High-performance polymers (BioHPP) with its CAD/CAM veneering composite using two different adhesives, as well as to dentin using two types of cements. MATERIALS AND METHODS: This in vitro study, for Group I, twenty BioHPP discs with their CAD/CAM veneering composite, were milled and divided randomly into two subgroups (n =10) according to the adhesive system used. Subgroup IA: using DTK adhesive (dualhardening adhesive). Subgroup IB: using Combo.lign (dual-hardening adhesive). For Group II, twenty CAD/CAM High-performance polymers (BioHPP) discs were milled and divided into two subgroups according to the different cements used to lute to dentin surface. Subgroup IIA: using: RelyX Unicem resin cement, subgroup IIB: using Fuji Plus GI cement. After water storage, thermocycling (1200 cycles, 5°C/55°C) corresponding to one year of clinical service, all the specimens were subjected to shear force until failure and the results in the various groups were compared and statistically analyzed. Modes of failure were assessed. RESULTS: Mean SBS were as follows: subgroup IA (DTK adhesive 6.238), subgroup IB (combo.lign2.42), subgroup IIA (RelyX Unicem 2.07) and subgroup IIB (Fuji Plus 3.77). Mann-Whitney test demonstrated significant differences between the two subgroups in groups I and II (U= 2.0, P=.001) (U=17, P=.013) respectively. Stereomicroscope revealed that mixed and adhesive failure were the most dominant mode of failure. CONCLUSIONS MDP-Containing Self-adhesive Resin (DTK adhesive) is recommended as efficient adhesive to increase the shear bond strength of the veneering composite to BioHPP. Also Fuji Plus showed better bond strength than RelyX Unicem with BioHPP and dentin.

Abutment screw loosening in angulation-correcting implants: An in vitro study

Statement of problemTechniques that allow angulation correction for screw-retained implant-supported restorations are now available. However, whether angulation correction built into the head of the implant affects abutment screw loosening is unclear. PurposeThe purpose of this in vitro study was to assess abutment screw loosening in angulation-correcting implants and straight implants subjected to simulated nonaxial occlusal loading. Material and methodsSeven external connection 12-degree angulation-correcting implants and 7 straight implants were embedded in an acrylic resin housing, and titanium abutments were secured with titanium screws tightened to 32 Ncm. Each specimen was secured in a tooth wear machine and subjected to 1 000 000 cycles of 50-N nonaxial load to simulate 1 year of clinical service. The mean abutment screw removal torque values were calculated, and the association between number of cycles and the abutment screw removal torque was analyzed using a linear mixed-effects model and statistical software (α=.05) ResultsThe mean abutment screw torque loss was 59.8% for the angulation-correcting implant group and 68.7% for the straight implant group. A statistically significantly greater mean abutment screw removal torque was recorded in the angulation-correcting implant group compared with the straight implant group after 1 000 000 cycles (P=.019). ConclusionsA significant loss of abutment screw torque was found in both implant groups with increased cycles of occlusal loading. The angulation-correcting implants resisted screw loosening significantly more than the straight implants because of the reduced angle of abutment screw loading.

Evaluation of some mechanical properties of a new silicone elastomer for maxillofacial prostheses after addition of intrinsic pigments

ObjectiveThe approximate life span of a silicone maxillofacial prosthesis is as short as 1.5–2 years of clinical service, then a new prosthesis should be fabricated. The most common reason for re-making the prosthesis is silicone mechanical properties degradation. The aim of this study was to assess some mechanical properties of VST-30 silicone for maxillofacial prostheses after addition of intrinsic pigments. MethodsTwo types of intrinsic pigments (rayon flocking and burnt sienna); each of them was incorporated into silicone. One hundred and twenty samples were prepared and split into 4 groups according to the conducted tests (tear strength, hardness, surface roughness, and tensile strength and elongation percentage) with 30 samples for each test. Each group was equally split into three subgroups. Group (A) was without pigment (control group), group (B) was with rayon flocking and group (C) was with burnt sienna. ResultsSamples with rayon flocking showed a highly significant decrease in hardness and there was a significant increase in tear strength, while there were non-significant differences in surface roughness, tensile strength and elongation percentage. Samples with burnt sienna showed a highly significant increase in tear strength and a highly significant decrease in hardness, but surface roughness, tensile strength and elongation percentage showed non-significant differences. However, there were non-significant differences between experimental groups in all tests. ConclusionsThe addition of each of rayon flocking and burnt sienna changed the mechanical properties of the VST-30 silicone, while no superior pigment-silicone combination was revealed in all the conducted tests.

Retrospective evaluation of extended heat-pressed ceramic veneers after a mean observational period of 7 years.

Retrospective evaluation of extended anterior glass-ceramic veneers 7 years after placement in a private practice. A total of 31 patients (20 females/11 males) underwent restoration with adhesively luted extended veneers that were fabricated using heat-pressed glass-ceramic (Cergo, Dentsply Sirona). A single dentist restored 101 teeth (maxilla, n = 65; mandible, n = 36). Adhesive cementation was performed using an etch-and-rinse adhesive (OptibondFL, Kerr Corporation), and two different dual-curing composite cements (Variolink, Ivoclar Vivadent/Calibra, Dentsply Sirona). After 7 years, the Kaplan-Meier survival rate (in situ criteria) was 93.6% (95% CI: 0.89; 0.98). The observed failures were caused by ceramic fractures for seven restorations and biological failure for one restoration. In total 80 of the 101 restorations were still in service and did not require any clinical intervention (7-year success rate: 84.3% [95% CI]: 0.76; 0.93). Interventions were necessary in 13 cases (8 recementations, 2 endodontic treatments, 2 composite fillings (caries), and 1 polishing of minor fractures). The clinical performance was not influenced by the veneer position (maxilla/mandible, survival P = .56/success P = .30). The veneers that covered large areas of exposed dentin (>50%) exhibited a significantly increased risk (hazard ratio 3.71, P = .0041) for requiring a clinical intervention; however, no effect on the survival rate was observed for these veneers (P = .35). Following 7 years of clinical service, extended anterior ceramic veneer restorations exhibited comparable survival and success rates for the upper and lower jaw. Large areas of exposed dentin (>50%) were associated with significantly lower success rates. Dentin exposure (more than 50% of the preparation surface) during preparation significantly affects the clinical performance of extended heat-pressed glass-ceramic veneers.

Nine-year Clinical Performance of a HEMA-free One-step Self-etch Adhesive in Noncarious Cervical Lesions.

One-step self-etch adhesives are among the most popular adhesives to directly bond composite to tooth tissue, mainly because of their perceived ease-of-use. The aim of this randomized controlled trial was to evaluate the clinical performance of a HEMA-free 1-step self-etch adhesive (1SEa), as compared with a 3-step etch-and-rinse adhesive (3E&Ra). 267 non-carious cervical lesions in 52 patients were restored with a microhybrid composite Gradia Direct (GC), bonded in random order either with the HEMA-free 1SEa G-Bond (GB; GC) or the considered gold-standard 3E&Ra Optibond FL (OFL; Kerr). The restorations were evaluated after 6 months, 1, 2, 3, 5 and 9 years of clinical service for retention, marginal adaptation, marginal discoloration, caries occurrence and tooth sensitivity. Statistical analysis was done using a logistic regression model with generalized estimating equations (2-way GEE model). The patient recall rate at 9 years was 82.6%. The overall clinical success rate was 80.3% and 79.5% for GB and OFL, respectively. In total, 47 restorations (23 GB, 24 OFL) failed because of retention loss, severe marginal defects and/or discoloration and/or caries. A similar retention rate of 89.7% was recorded for both adhesives GB and OFL. Slight marginal defects and superficial marginal discoloration, though both still clinically acceptable, were significantly more observed at the incisal enamel side of GB (92.4% and 52.1%, respectively) than OFL (59.6%; 30.8%) restorations (p < 0.05). After 9 years of clinical service, class-V restorations bonded with the HEMA-free 1SEa performed clinically equally successful as those bonded with the 3E&Ra. However, more marginal deterioration, though still clinically acceptable, was recorded at the incisal enamel side for the 1SEa.

Influence of Different CAD/CAM Crown Materials on the Fracture of Custom-Made Titanium and Zirconia Implant Abutments After Artificial Aging.

To investigate the effects of different commercially available computer-aided design/computer-assisted manufacturing (CAD/CAM) materials for fabrication of molar crowns, including polyetheretherketone (PEEK), on the fracture strength and failure mode of custom-made titanium and zirconia abutments after artificial aging. A total of 48 identical custom-made CAD/CAM abutments milled out of titanium or zirconia were divided into six test groups of eight specimens each. The groups were assigned as follows: titanium abutments restored with zirconia crowns (TiZ), with lithium disilicate crowns (TiL), or with PEEK crowns (TiP); zirconia abutments bonded to a titanium base and restored with zirconia crowns (ZrZ), with lithium disilicate crowns (ZrL), or with PEEK crowns (ZrP). The specimens were artificially aged in a chewing simulator for 1.2 million cycles of dynamic loading with simultaneous thermal cycling and then loaded to fracture in the universal testing machine. Shapiro-Wilk test was used to test for normality. One-way analysis of variance followed by post hoc analysis using Bonferroni test was used to detect statistically significant differences among groups. All specimens survived the artificial aging process simulating 5 years of clinical service. The fracture patterns and means of the fracture strength (N) varied between groups: TiZ = 4,926 N; TiL = 3,706 N; TiP = 3,878 N; ZrZ = 5,529 N; ZrL = 2,826 N; and ZrP = 3,967 N. Although the tested combinations showed different fracture patterns and loads, all tested abutment and crown materials and their different combinations could be considered to have fracture strengths suitable for clinical application.

Clinical evaluation of three adhesive systems in class V carious lesions

Purpose The purpose of this study was to evaluate the clinical performance of three types of adhesive systems (Futurabond universal adhesive in a self-etch mode, Tetric N-bond self-etch adhesive, and Single bond universal adhesive in a total etch mode) in class V carious lesions over 1 year. Materials and methods A total of 20 patients with three carious cervical lesions were participated in this study after obtaining informed consent. A total of 60 restorations were placed. The distributions of adhesive materials and the teeth locations were randomized. Cavities were prepared limited to just removal of carious lesions with incisal and gingival margins in enamel and beveling of incisal cavosurface margin. All adhesives were applied following manufacturer's directions. All cavities were restored with Grandio SO composite resin following manufacturer's directions. Finishing and polishing was performed using finishing burs and polishing discs. Each restoration was clinically evaluated at baseline (24 h), 6 months and 1 year for retention, margin integrity, margin discoloration, secondary caries, and postoperative sensitivity using modified United state public health service (USPHS) criteria. Results The recall rate was 100% after 1 year. Also the retention rate for all restorations was 100% after 1 year. Using χ2-test, there was no statistically significant differences between the tested groups at all evaluation periods regarding marginal adaptation, marginal discoloration, and postoperative sensitivity (P > 0.05). None of restoration had secondary caries at any evaluation period. Conclusion Within the limitation of this short-term evaluation, there was no significant clinical difference between adhesives. Clinical significances All tested adhesive systems achieved excellent results after 1 year of clinical service.

Retrospective clinical evaluation of posterior monolithic zirconia restorations after 1 to 3.5 years of clinical service

This retrospective study analyzed clinical outcomes of monolithic zirconia restorations (MZRs) and factors related to restoration success. Patient records were searched to identify those provided MZRs (Cercon ht) for premolars or molars between April 2012 and March 2016. All MZRs were placed according to a standardized protocol. Kaplan-Meier analysis was used to assess MZR performance and failure after recall appointments at 1 year or later. In total, 101 patients received 148 MZRs. Mean duration of follow-up was 25.0 ± 9.9 months. Six MZRs required replacement: three because of pulpal complications, one because of root fracture of an abutment tooth, one because of restoration fracture, and one because the tooth was used as an abutment tooth for a fixed partial denture after root fracture of an adjacent tooth. The cumulative MZR survival (success) rate at 3.5 years was 91.5% (95% confidence interval, 82.1% to 100%). The findings of this short-term retrospective study indicate that posterior MZRs are a therapeutic option for certain patients. In addition, several clinical procedures contribute to MZR success, including preparation design and occlusal and adhesive surface treatments.

Clinical Results and Technical Complications of Posterior Implant-Supported Modified Monolithic Zirconia Single Crowns and Short-Span Fixed Dental Prostheses: A 2-Year Pilot Study.

The purpose of this clinical trial was to investigate the clinical outcomes of implant-supported modified monolithic zirconia single crowns (SCs) and short-span fixed dental prostheses (FDPs) after a follow-up of 2 years. Twenty-seven patients in need of implant-supported SCs or 3-unit FDPs in the posterior maxilla or mandible were consecutively selected for this study. A total of 56 modified monolithic zirconia prostheses including 44 SCs (8 screw-retained, 36 cement-retained) and twelve 3-unit FDPs (5 screw-retained, 7 cement-retained) were included in this study. All patients were followed at 6 months, 12 months, 18 months, and 2 years after placement of the modified monolithic zirconia prostheses. During the follow-up period, all prostheses were evaluated with clinical and radiographic examinations. The following technical parameters were assessed: framework fracture, fracture of veneering porcelain, screw loosening, loss of retention because of prosthesis de-cementation and opposing tooth fracture. No implant was lost during the follow-up period, yielding a 2-year implant survival of 100%. One FDP failed because of framework fracture. The overall prosthesis survival rate was 98.2% after 2 years of clinical service. During the study, 5 complication events were observed in 3 SCs and one FDP, including one fracture of veneering porcelain and 2 screw loosenings in 3 SCs, and loss of retention and opposing tooth fracture in the same FDP. Therefore, the complication-free rate of prostheses was 91.1%. According to the results of this study, the modified monolithic zirconia design used in this study resulted in a favorable short-term outcome for posterior implant-supported SCs and 3-unit FDPs.

EVALUATION OF ZIRCONIA-REINFORCED LITHIUM SILICATE CERAMIC SURFACE TREATMENT ON THEIR SHEAR BOND STRENGTH TO DENTINE FOLLOWING IMMEDIATE DENTIN SEALING

Objectives: The purpose of this study was to evaluate zirconia-reinforced lithium silicate ceramic surface treatment on their shear bond strength to dentine following immediate dentin sealing.Methods : One hundred sixty extracted molars were initially divided into two main groups each counting eighty molars: based on dentine sealing protocols (without immediate dentin sealing S- and with immediate dentin sealing S+), those groups were further subdivided into four subgroups each counting twenty based on the ceramic surface treatment protocol. Each were further subdivided into two subdivisions to evaluate the bonding durability after thermodynamic aging process each counting ten specimens. All restorations were adhesively bonded using a light curing resin cement. The thermo-mechanical group were subjected to 10,000 thermal cycles between (5-55oC) with a 30-s dwell time, 20 seconds transfer time. specimens were then subjected to maximum vertical load of 10 kg with cyclic frequency of 1.7 Hz for 240,000 cycles, which corresponds to one year of clinical service. Specimens were tested for shear bond strength using Instron testing machine. Data were statistically analyzed using two-way ANOVA and Tukey’s post-hoc tests.Result: A significantly higher shear bond strength of restorations (p ≤ 0.001) was obtained when immediate dentin sealing was followed regardless of the surface treatments of ceramics with a maximum value of 10.50±0.412 MPa. Both ceramic surface treatment and artificial aging had a statistically significant effect on the shear bond strength.Conclusion: Immediate dentin sealing protocol is recommended and HF surface treatment is recommended for ceramic restorations adhesion to achieve better durability.

Survival of 2039 complete arch fixed implant-supported zirconia prostheses: A retrospective study

Statement of problemPresently, data for the survival of 1-piece complete arch fixed implant-supported zirconia prostheses are limited. PurposeThe purpose of this retrospective study was to evaluate the survival outcomes of 1-piece complete arch fixed implant-supported zirconia prostheses fabricated by a single dental laboratory supporting several clinicians. Material and methodsOutcome data were collected over a 5-year period from a large commercial dental laboratory that fabricated 2039 1-piece complete arch fixed implant-supported monolithic zirconia prostheses. All prostheses were fabricated using the same zirconia system from 1 manufacturer, using standardized protocols. The zirconia prostheses were predominantly monolithic, with veneered porcelain restricted to the gingival region. Because a 5-year warranty against fracture was offered by this dental laboratory, prostheses that were returned to the laboratory for remake because of catastrophic failure (fracture) or technical complications were identified, and data were analyzed using a life table. ResultsOf the 2039 zirconia prostheses evaluated, at least 319 prostheses had a minimum of 3 years of clinical service, and 69 prostheses had a minimum of 4 years of clinical service. A total of 6 fractures were reported, resulting in a first-year interval survival rate of 99.8% and a 5-year cumulative survival rate of 99.3%. Six zirconia prostheses were returned to the laboratory during the 5-year period because of technical complications related to the debonding of titanium cylinders, and 3 prostheses were returned because of fracture of the titanium cylinders. No prostheses were returned because of chipping of the veneered gingival porcelain. ConclusionsPractice-based evidence from this large sample, short-term retrospective study showed that 1-piece complete arch fixed implant-supported zirconia prostheses with veneered porcelain restricted to the gingival region showed a cumulative survival rate of 99.3% in a 5-year period. The technical complication rate related to this type of prosthesis was minimal.

In-vitro Fatigue Resistance of Bonded Posterior Occlusal Veneers: A Systematic Review

Objectives: To determine the fatigue resistance of occlusal veneers and whether it can be a successful mean of restoring erosive or attrite posterior teeth. Methods: Search was made in 2 databases including PubMed and LILACS, the terms “occlusal veneers”, “table tops”, “overlays”, “non retentive all ceramic full coverage restorations”, “fatigue resistance”, “ masticatory fatigue”, “stresses”, “fatigue failure” and “fracture strength” were used, title and abstract were screened; giving the exclusion and inclusion standards articles which did not follow the inclusion standards were excluded. Incorporated papers are then read thoroughly for a second stage filter, this was followed by manual searching. Findings: The search resulted in 6 included papers, 3 papers regarding the fatigue resistance of occlusal veneers made of composite and glass ceramic blocks, 1 paper measuring the fatigue resistance of occlusal veneers made of two different glass ceramics, 1 paper comparing occlusal veneers made of resin nano-ceramic with those made of composite blocks and 1 paper simulating five years of clinical service on occlusal veneers made of one type of glass ceramic. From the included studies occlusal veneers were found to be a successful mean of restoring erosive or attrite posterior teeth regarding fatigue resistance.

Outcome of zirconia partial fixed dental prostheses made by predoctoral dental students: A clinical retrospective study after 3 to 7 years of clinical service

Statement of problemZirconia has an established role in fixed prosthodontics, especially for single crowns. Whether it is durable enough for fixed dental prostheses (FDPs) in the long term is yet unclear. PurposeThe purpose of this retrospective study was to evaluate the outcome of FDPs made by predoctoral students after 3 to 7 years of clinical service. Material and methodsA total of 102 patients received 120 zirconia FDPs (range, 3-12 units; mean, 4.5 units) between 2007 and 2010. Materials used were Zirkonzahn Zirconia (Zirkonzahn), NobelProcera Zirconia (Nobel Biocare), and Prettau Zirconia (Zirkonzahn). Veneering porcelain was hand-layered on Zirkonzahn Zirconia (GC Initial Zr; GC Europe) and Nobel Procera Zirconia (VITA VM 9; VITA Zahnfabrik). Prettau Zirconia was monolithic and had no veneering porcelain. Success and survival rates were calculated using Kaplan-Meier survival analysis. Ethics approval was obtained from the Ethical Committee of the Northern Ostrobothnia Hospital District (100/2013). ResultsThe 76 participants examined (75%) had received 88 zirconia FDPs. The mean follow-up period was 4.9 years (range, 3-7 years). The most common complication was chipping of the veneering porcelain in 13 of 88 FDPs (14.7%). The success rate of the zirconia-based partial FDPs after 4.9 years was 89%, and the survival rate was 100%. ConclusionsThe success rate of the zirconia-based partial FDPs after 4.9 years was 89%, and the survival rate was 100%.

Survival of all-ceramic restorations after a minimum follow-up of five years: A systematic review.

The purpose of this systematic review was to compare the survival and complication rates of all-ceramic restorations after a minimum follow-up time of 5 years. A comprehensive search of studies published from 2005 to November 2015 and listed in the PubMed/MEDLINE, Scopus, and Cochrane Library databases was performed in accordance with the PRISMA statement. Two reviewers independently analyzed the abstracts. Relevant studies were selected according to predetermined inclusion criteria. Twenty-nine studies were selected for the final analysis from an initial yield of 514. Only four studies fulfilled the requirement of having a randomized design, and 25 studies were prospective with a mean follow-up period of 5 to 16 years. Overall, the 5-year complication rates were low. The most frequent complications were secondary caries, endodontic problems, ceramic fractures, ceramic chipping, and loss of retention. This systematic review showed that all-ceramic restorations fabricated using the correct clinical protocol have an adequate clinical survival for at least 5 years of clinical service with very low complication rates. Minor ceramic chipping and debonding did not affect the longevity of the restorations. Long-term clinical performance of all-ceramic restorations manufactured using various ceramic systems provides clinical evidence of complications and long-term management of these restorations. Available evidence indicates the effectiveness of many ceramic systems for numerous clinical applications. Correct planning and a rigorous technical execution protocol increase clinical success. Studies of ceramic prostheses indicate more problems with ceramic failure and debonding.

Two-year clinical evaluation of resin composite in posterior teeth: A randomized controlled study.

Background:Clinical evaluations as fundamental method to prove the efficiency of restorative materials.Aim:This study evaluated the clinical performance of restorative systems during 2 years of clinical service.Materials and Methods:This study assessed the clinical performance of restorative systems (Filtek Z250 and P60), during 2 years of clinical service, using the US Public Health Service system. The randomized and double-blind study comprising thirty volunteers. The restorations were evaluated at baseline, 6, 12, and 24 months. It was used the following criteria: marginal discoloration (MD), marginal integrity (MI), superficial texture (ST), wear (W), postoperative sensitivity (PS) and recurrent caries (RC).Results:Statistic analysis was performed using Fisher's and McNemar's exact tests and Pearsons's Chi-square in a significance level of 5%. The results at baseline and 24 months for Group I were: MD – 100, 100%; MI – 100, 88.6%; ST – 100, 94.3%; W – 100, 94.3%; PS – 100, 100%; RC – 100, 100%, of alpha scores; Group II: MD – 100, 97.1%; MI – 100, 91.4%; ST – 100, 94.3%; W – 100, 91.4%; PS – 100, 100%; RC – 100, 100%, of alpha scores. It was observed no statistical difference in the evaluated criteria and period.Conclusions:After 24 months of evaluation, both restorative systems exhibited acceptable clinical performance.

Clinical Bonding of Resin Nano Ceramic Restorations to Zirconia Abutments: A Case Series within a Randomized Clinical Trial.

New dental materials are introduced and promoted in the field without extensive clinical testing. Using those materials in a clinical setting might result in unacceptable early failure rates. The purpose of this paper was to analyze bonding of a new dental restorative material to either zirconia stock abutments or zirconia customized abutments. Fifty participants seeking single implant treatment were included in a prospective study. Resin Nano Ceramic (RNC, Lava Ultimate, 3M ESPE, Seefeld, Germany) crowns were digitally manufactured and extraorally bonded to either a stock or a customized zirconia abutment (ZirDesign and ATLANTIS, DENTSPLY Implants, Mölndal, Sweden) by means of a resin composite cement (RelyX Ultimate in combination with Scotchbond Universal, 3M ESPE), strictly following the manufacturer's recommendations. The final restorations were screw-retained to the implants and followed during 12 months. Primary outcome parameter was uncompromised survival of the restoration, and secondary outcome parameter was mode of failure. No implants were lost. The uncompromised survival rate of the RNC crowns bonded to zirconia abutments after 1 year of clinical service was only 14% (n = 7). Catastrophic failure occurred in three cases (6%), whereas bonding failure between RNC crowns and zirconia abutments occurred in 80% of the cases (n = 40) within the first year of service. No statistical significant difference in uncompromised survival rate could be identified between abutment types (χ2 = 1.495, p = .209). Uncompromised survival rate after 1 year was highly significantly different (χ2 = 104.173, p < .001) from a reference standard, which was set at 95%. RNC crowns luted to stock and customized zirconia implant abutments with the particular resin composite cement in this trial have a poor prognosis, regardless of the abutment type used.

Full-Arch, Implant-Supported Monolithic Zirconia Rehabilitations: Pilot Clinical Evaluation of Wear Against Natural or Composite Teeth.

To clinically evaluate the amount of contact wear generated between full-arch monolithic zirconia implant-supported restorations and natural or composite antagonists, over a 1-year period. Forty-seven teeth from clinically functional, full-arch monolithic zirconia screw-retained implant prostheses (FDPs) and their antagonists were investigated. The first group ("Zirconia-E") was opposed to natural teeth ("Enamel"), whereas the other one ("Zirconia-CR") was opposed to nano-hybrid composite teeth ("Composite Resin"). Replicas of the restorations and their antagonists were obtained immediately after delivery (T0 ) and after 1 year of clinical service (T1 ). Each tooth surface was individually evaluated three-dimensionally by software to quantify the vertical distance between the two scans (Hausdorff distance), which was considered as contact wear. Data obtained for each arch were subjected to one-way ANOVA test and a post hoc analysis (Tukey's test) at a 5% level of significance. Furthermore, the influence of the location of the teeth (anterior or posterior) was analyzed. Minimum post hoc statistical power between statistically different groups was 99.6%. Mean values were 63 ± 23 μm for Zirconia-E, 76 ± 29 μm for enamel, 70 ± 38 μm for composite resin; Zirconia-CR had a mean value of 19 ± 4 μm and significantly differed from the other groups. Contact wear between anterior and posterior teeth differed significantly only in the composite resin arch, with a mean of 39 ± 22 μm for anterior teeth versus 101 ± 19 μm for posterior ones. Within the limitations of this preliminary evaluation, monolithic zirconia full-arch rehabilitations induced a clinically acceptable wear on natural and composite antagonists over a 1-year period; they might be considered a viable solution for implant-supported rehabilitations.

A randomized controlled clinical trial of 3-unit posterior zirconia–ceramic fixed dental prostheses (FDP) with layered or pressed veneering ceramics: 3-year results

ObjectivesThe aim of the present pilot study was to test whether or not posterior zirconia–ceramic fixed dental prostheses (FDPs) with pressed veneering ceramic exhibit less chipping than FDPs with layered veneering ceramics. MethodsForty patients (13 female, 27 male; mean age 54 years (range 26.1–80.7 years) in need of one maxillary or mandibular three-unit FDP in the second premolar or molar region were recruited and treated at two separate centers at the University of Zurich according to the same study protocol. The frameworks were made out of zirconia using a CAD/CAM system (Cerec Sirona, Bensheim, Germany). The patients were randomly assigned to either the test group (zirconia frameworks veneered with pressed ceramic; IPS e.max ZirPress, Ivoclar Vivadent AG, Schaan, Liechtenstein; n=20) or the control group (layered veneering ceramic; IPS e.max Ceram, Ivoclar Vivadent AG, Schaan, Liechtenstein; n=20). All FDPs were adhesively cemented and evaluated at baseline (i.e., cementation), at 6 months and at 1 and 3 years of clinical service. The survival of the reconstruction was recorded. The technical outcome was assessed using modified United States Public Health Services (USPHS) criteria. The biologic parameters analyzed at abutment teeth and analogous non-restored teeth included probing pocket depth (PPD), plaque control record (PCR), bleeding on probing (BOP), and tooth vitality (CO2). Data was descriptively analyzed and survival was calculated using Kaplan–Meier statistics. Results36 patients (25 female, 11 male; mean age 52.3 years) with 18 test and 18 control FDPs were examined after a mean follow-up of 36 months (95% CI: 32.6–39.1 months). Comparison of groups was done by Crosstabulation showing even distribution of the respective restored teeth amidst the groups. Survival rate was 100% for both test and control FDPs. Chipping of the veneering ceramic tended to occur more frequently in test (n=8; 40%) than in control (n=4; 20%) FDPs, albeit not significantly (p=0.3). No further differences of the technical outcomes of test and control FDPs occurred.In both test and control group healthy conditions and no difference of the biologic parameters at the abutment and un-restored teeth was found. ConclusionZirconia FDPs with pressed and layered veneering ceramics exhibited similar outcomes at 3 years. A trend to more chipping of the pressed veneering ceramic, however, was observed. Clinical significancePosterior restorations with zirconia frameworks are a viable treatment method. When restoring posterior teeth with all-ceramic restorations, care providers should be aware of the higher rate of chipping compared to the published data on conventional metal-ceramic restorations.