Clinical performance of single implant prostheses restored using titanium base abutments: A systematic review and meta-analysis

One-Piece Monolithic Zirconia Single Tooth Implant-Supported Restorations in the Posterior Region: A 1-Year Prospective Case Series Study

OBJECTIVE

To assess the clinical, radiographic and patient-reported outcome measures, and the success of screw-retained one-piece monolithic zirconia implant-supported restorations in the posterior region during a 1-year follow-up.

METHODS

In a prospective case series, 50 single molar sites in the posterior region of 41 patients with a minimum age of 18 years and sufficient bone volume for placing an implant (≥ 8 mm) and space for an anatomical restoration were included. Following prosthetic-driven digital three-dimensional treatment planning, a tissue-level implant with an internal connection was inserted during a one-stage surgical procedure. Three months later, the implant was restored with a screw-retained one-piece monolithic zirconia restoration. Clinical, radiographic and patient-reported outcome measures, and restoration survival and success according to the modified USPHS criteria were assessed at baseline prior to and immediately after implant placement, and 1-month and 1-year after definitive restoration placement.

RESULTS

At the 1-year follow-up, 1 implant had been lost (implant survival rate 98%) hence, 49 restorations were evaluated. The restoration survival and success rates were 100% and 98%, respectively. Plaque, calculus, bleeding and suppuration on probing and peri-implant inflammation were absent in most cases. The mean (SD) marginal bone level change between implant placement and the 1-year follow-up was -0.14 mm (0.27) on the mesial and -0.25 mm (0.31) on the distal side. The mean (SD) patient satisfaction (0-10) was 9.2 (0.8) at the 1-year evaluation.

CONCLUSION

One-piece monolithic zirconia implant-supported restorations exhibited favourable outcomes over 1 year in situ.

TRIAL REGISTRATION

Registered in the National Trial Register (NL9059).

Load-bearing capacity of screw-retained fixed dental prostheses made of monolithic zirconia on different abutment designs and abutment-free implant connection

OBJECTIVES

A new abutment-free implant connection allows for direct screwing of FDPs on implants to avoid complications caused by cement rests or screw loosening, which may affect to screw torque and load distribution. The objective of this study was to test the initial (Fi) and final failure (Ff) loads and torque changes of abutment-free monolithic zirconia CAD-CAM fixed dental prostheses (FDPs) compared to titanium FDPs on different abutment designs.

METHODS

Three-unit screw-retained FDPs (n = 50) on two implants (n = 100) were divided into groups (n = 10) based on the implant-abutment connection and material of the supra-structure: (1) abutment-free monolithic CAD-CAM zirconia FDP (Abut-free-Zr), (2) abutment-free veneered titanium FDPs (Abut-free-Ti), (3) monolithic zirconia FDPs with titanium base abutments (Zr-Ti-Base), (4) monolithic zirconia FDPs on multi-unit abutments (Zr-MU), (5) veneered titanium FDP on multi-unit abutments (Ti-MU). All specimens were subjected to thermo-mechanical aging (1'200'000 Cycles, 49 N, 1.67 Hz, 5º to 50º C, dwelling time 120 s). Torque of the screws was measured, and static loading was performed. Data were tested using ANOVA and Tukey's tests (p < 0.05).

RESULTS

After thermo-mechanical aging, all screws showed reduced torque, Ti-MU significantly more reduction compared to Abut-Free-Ti (p = 0.0021). Titanium groups showed significantly lower Fi (N) values (171.4-230 vs 1272-1358,) due to veneering porcelain fractures (p = 0.0001) and significantly higher Ff (N) (2922 -3029 N vs. 1272-1358) values than zirconia groups (p < 0.0001).

CONCLUSIONS

Three-unit abutment-free monolithic zirconia FPDs showed similar failure loads compared to other zirconia groups, while the titanium groups exhibited superior final failure loads. Different abutment designs did not seem to affect the failure loads.

CLINICAL SIGNIFICANCE

The specific design of the novel implant interface allows for the fabrication of implant supported FDPs with personalized design directly on implant level without abutments. The monolithic zirconia FDPs on abutment-free implant connection can be used with good confidence since they exhibit similar mechanical stability as monolithic zirconia FDPs on titanium-base or multi-unit abutments.

Antibacterial Properties of PMMA/ZnO(NanoAg) Coatings for Dental Implant Abutments

Infections continue to pose significant challenges in dentistry, necessitating the development of innovative solutions that can effectively address these issues. This study focuses on creating coatings made from polymethyl methacrylate (PMMA) enriched with zinc oxide-silver composite nanoparticles, layered to Ti6Al4V-titanium alloy substrates. The application of these materials aims to create a solution for the abutments utilized in complete dental implant systems, representing the area most susceptible to bacterial infections. The nanoparticles were synthesized using a hydrothermal method, optimized through specific temperature and pressure parameters to achieve effective morphologies and sizes that enhance antibacterial efficacy. The layers were applied to the titanium substrate using the spin coating technique, chosen for its advantages and compatibility with the materials involved. Comprehensive analyses were conducted on the antimicrobial powders, including X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Furthermore, the PMMA-based coatings incorporating antimicrobial nanoparticles were evaluated to ensure uniformity and homogeneity across the titanium alloy surface by IR mapping and SBF immersion-SEM analysis. The antimicrobial activity of the samples was demonstrated with impressive results against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, as assessed through biofilm modulation studies. The biocompatibility of the samples was validated through in vitro cell-based assays, which demonstrated excellent compatibility between PMMA-based coatings and human preosteoblasts, confirming their potential suitability for future use in dental implants.

Wide Restorative Emergence Angle Increases Marginal Bone Loss and Impairs Integrity of the Junctional Epithelium of the Implant Supracrestal Complex: A Preclinical Study

AIM

To assess the influence of the emergence angle on marginal bone loss (MBL) and supracrestal soft tissue around dental implants.

MATERIALS AND METHODS

In six mongrel dogs, the mandibular premolars and molars were extracted. After 3 months of healing, four dental implants were placed in each hemimandible. The implants were randomly allocated to receive one of four customized healing abutments, each with a different value of the restorative emergence angle: 20°, 40°, 60° or 80°. Intra-oral radiographs were taken after placing the healing abutments and at 6, 9, 16 and 24 weeks of follow-up. Then, micro-CT and undecalcified histology and synchrotron were performed. MBL over time was analysed with generalized estimating equations (GEEs) and adjusted for baseline soft-tissue thickness.

RESULTS

From implant placement to 24 weeks, GEE modelling showed that the MBL at mesial and distal sites consistently increased over time, indicating MBL in all groups (p < 0.001). The model indicated that MBL varied significantly across the different restorative angles (angle effect, p < 0.001), with 80° showing the greatest bone loss. Micro-CT, histology and synchrotron confirmed the corresponding trends and showed that wide restorative angles (60° and 80°) impaired the integrity of the junctional epithelium of the supracrestal tissue.

CONCLUSIONS

A wide restorative angle increases MBL and impairs the integrity of the junctional epithelium of the implant supracrestal complex.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of select 2023 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertize in their subject areas that include (in order of appearance here): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine, oral and maxillofacial surgery, and oral radiology; and dental caries and cariology. The authors have focused their efforts on presenting information likely to influence the daily dental treatment decisions of the reader with an emphasis on current innovations, new materials and processes, emerging technology, and future trends in dentistry. With the overwhelming volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to inform and update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope readers find this work helpful in providing evidence-based care to patients seeking healthier and happier lives.

Clinical outcomes of single implant supported crowns utilising the titanium base abutment: A 7.5-year prospective cohort study

OBJECTIVE

To assess radiographic, clinical and patient-reported outcomes of single zirconia implant-supported crowns on titanium base abutments (TBA) over a 7.5-year period.

METHODS

Twenty-four patients received bone-level titanium implants and screw-retained zirconia implant crowns utilising TBA. Marginal bone level (MBL), clinical parameters (probing depth-PD, bleeding on probing-BoP, plaque control record-PCR), technical complications (USPHS criteria) and patient satisfaction were assessed at crown delivery (baseline), 1 year (FU-1) and at 7.5 years (FU-7.5) of follow-up.

RESULTS

Eighteen patients were available for re-examination at 7.5 years. The mean MBL at FU-7.5 (0.35 ± 0.20mm) did not significantly change compared to baseline (0.54 ± 0.39, p=.352) and to FU-1 (0.54 ± 0.45mm, p=0.524). From baseline to 7.5 years, the mean PD increased significantly, from 3.0 ± 0.6mm to 3.7 ± 0.8mm (p=0.005). However, BoP and PCR did not significantly change; (BOP: from 27.1 ± 20.7% to 25.0 ± 20.0%, p=0.498; PCR: from 11.1 ± 21.2% to 25.0 ± 25.1%, p=0.100). Nine patients presented with more than one bleeding site. This denoted a peri-implant mucositis prevalence of 50%, whilst none of the implants presented peri-implantitis. One incidence of minor and major ceramic chipping were reported on 2 out of the 18 crowns, resulting in a prosthetic survival rate of 94.4%. Seventeen patients were highly satisfied with their result.

CONCLUSION

Single implant-supported zirconia crowns on TBA displayed: (i) minor number of technical complications, (ii) high prosthetic survival rate, (iii) stable marginal bone level and (iv) high patient satisfaction at 7.5 years.

CLINICAL IMPLICATIONS

Titanium base abutments despite their high use in clinical practice, lacked medium- and long-term studies. The presented findings highlight their clinical performance at 7.5 years as they display satisfying radiographic, clinical and patient-related outcomes. TBA appear to be a suitable abutment choice for medium-term implant-supported restorations.

Do all ceramic and composite CAD-CAM materials exhibit equal bonding properties to implant Ti-base materials? An Interfacial Fracture Toughness Study

OBJECTIVES

To compare the interfacial fracture toughness (IFT) with or without aging, of four different classes of CAD-CAM ceramic and composite materials bonded with self-adhesive resin cement to titanium alloy characteristic of implant abutments.

METHODS

High translucent zirconia (Katana; KAT), lithium disilicate-based glass-ceramic (IPS. emax.CAD; EMX), polymer-infiltrated ceramic network material (PICN) (Vita Enamic; ENA), and dispersed filler composite (Cerasmart 270; CER) were cut into equilateral triangular prisms and bonded to titanium prisms with identical dimensions using Panavia SA Cement Universal. The surfaces were pretreated following the manufacturers' recommendations and developed interfacial area ratio (Sdr) of the pretreated surfaces was measured. IFT was determined using the Notchless Triangular Prism test in a water bath at 36 °C before and after thermocycling (10,000 cycles) (n = 40 samples/material).

RESULTS

IFT of the materials ranged from 0.80 ± 0.25 to 1.10 ± 0.21 MPa.m1/2 before thermocycling and from 0.71 ± 0.24 to 1.02 ± 0.25 MPa.m1/2 after thermocycling. There was a statistical difference between IFT of CER and the two top performers in each scenario: KAT and EMX before aging, and KAT and ENA after aging. Thermocycling significantly decreased IFT of EMX. The Weibull modulus of IFT was similar for all materials and remained so after thermocycling. Sdr measurements revealed that ENA (7.60)>Ti (4.97)>CER (2.85)>KAT (1.09)=EMX (0.96).

SIGNIFICANCE

Dispersed filler CAD-CAM composite showed lower performance than the other materials. Aging only affected IFT of Li-Si glass-ceramic, whereas zirconia and PICN performed equally well, probably due to their chemical bonding potential and surface roughness respectively.

Material and abutment selection for CAD/CAM implant-supported fixed dental prostheses in partially edentulous patients - A narrative review

Restorative material selection has become increasingly challenging due to the speed of new developments in the field of dental material science. The present narrative review gives an overview of the current indications for implant abutments and restoration materials for provisional and definitive implant-supported fixed dental prostheses in partially edentulous patients. For single implant restorations, titanium base abutments for crowns are suggested as an alternative to the conventional stock- and customized abutments made out of metal or zirconia. They combine the mechanical stability of a metallic connection with the esthetic potential of ceramics. For multiple-unit restorations, conical titanium bases especially designed for bridges are recommended, to compensate for deviating implant insertion axes and angulations. Even though titanium base abutments with different geometries and heights are available, certain clinical scenarios still benefit from customized titanium abutments. Indications for the definitive material in fixed implant restorations depend on the region of tooth replacement. In the posterior (not esthetically critical) zone, ceramics such as zirconia (3-5-Ymol%) and lithium-disilicate are recommended to be used in a monolithic fashion. In the anterior sector, ceramic restorations may be buccally micro-veneered for an optimal esthetic appearance. Lithium-disilicate is only recommended for single-crowns, while zirconia (3-5-Ymol%) is also recommended for multiple-unit and cantilever restorations. Attention must be given to the specific mechanical properties of different types of zirconia, as some feature reduced mechanical strengths and are therefore not indicated for all regions and restoration span lengths. Metal-ceramics remain an option, especially for cantilever restorations.

The influence of titanium-base abutment geometry and height on mechanical stability of implant-supported single crowns

AIM

This study aimed to investigate the influence of titanium base (ti-base) abutment macro- and micro-geometry on the mechanical stability of polymer-infiltrated ceramic network (PICN) screw-retained implant-supported single crowns (iSCs).

MATERIALS AND METHODS

Twelve specimens per group were used, comprising six different implant/ti-base abutment combinations restored with PICN iSCs: Nb-T (gingival height [GH]: 1.5 mm, prosthetic height [PH]: 4.3 mm), CC (GH: 0.8 mm, PH: 4.3 mm), CC-P (GH: 0.8 mm, PH: 7 mm), Nb-V (GH: 1.5 mm, PH: 6 mm), St (GH: 1.5 mm, PH: 5.5 mm), and Th (GH: 0.5 mm, PH: 9 mm). The specimens underwent thermo-mechanical aging, and those that survived were subsequently subjected to static loading until failure. The data were analyzed using a one-way ANOVA test followed by Tukey post hoc test (α = .05).

RESULTS

All specimens survived thermo-mechanical aging without complications, namely, visible cracks, debonding, or screw loosening. Th group demonstrated the highest strength values among all the groups, with significant differences compared to Nb-T (p < .05), CC (p < .001), and St (p < .001). Additionally, CC-P group exhibited significantly superior fracture strength results compared to CC (p < .05) and St (p < .05).

CONCLUSION

The choice of ti-base, particularly prosthetic height, had a significant influence on fracture resistance of PICN iSCs. Nevertheless, the height or geometrical features of the ti-base did not exhibit a significant influence on the mechanical behavior of the iSC/ti-base assembly under thermomechanical loading, as all specimens withstood the aging without complication or failure.

Effect of cement type, luting protocol, and ceramic abutment material on the shade of cemented titanium-based lithium disilicate crowns and surrounding peri-implant soft tissue: a spectrophotometric analysis

PURPOSE

The objective of the study was to analyze the impact of cement, bonding pretreatment, and ceramic abutment material on the overall color results of CAD-CAM ceramic crowns bonded to titanium-based hybrid abutments.

MATERIALS AND METHODS

For single implant restoration of a maxillary lateral incisor a total of 51 CAD-CAM-fabricated monolithic lithium disilicate crowns were fabricated and subsequently bonded onto 24 lithium disilicate Ti-base abutments, 24 zirconia Ti-base abutments and 3 resin abutment replicas as a control group. The 48 copings were cemented with three definitive and one provisional cement on both grit-blasted and non-blasted Ti-bases. The color of each restoration and surrounding artificial gingiva was measured spectrophotometrically at predefined measuring points and the CIELAB (ΔEab) color scale values were recorded.

RESULTS

The color outcome of ceramic crowns bonded to hybrid abutments and soft tissues was affected differently by cements of different brands. Grit-blasting of Ti-bases prior to cementing CAD-CAM copings affected the color results of all-ceramic crowns. There was a significant difference (P = .038) for the median ΔE value between blasted and non-blasted reconstructions at the cervical aspect of the crown. Full-ceramic crowns on zirconia Ti-base abutments exhibited significantly lower ΔE values below the threshold of visibility (ΔE 1.8). In all subcategories tested, the use of a highly opaque temporary cement demonstrated the lowest median ΔE for both the crown and the artificial gingiva.

CONCLUSION

Various cements, core ceramic materials and airborne particle abrasion prior to bonding can adversely affect the color of Ti-base supported ceramic crowns and peri-implant soft tissue. However, zirconia CAD-CAM copings and an opaque cement can effectively mask this darkening.

Clinical performance and risk factors of all-ceramic screw-retained implant crowns in the posterior region based on a retrospective investigation

OBJECTIVES

Clinical data on all-ceramic screw-retained implant crowns (SICs) luted on titanium base abutments (TBAs) over more than 3 years are sparse. This study aimed to evaluate the clinical performance and potential risk factors for these restorations.

MATERIALS AND METHODS

Analysis took place based on the medical patient-records of three dental offices. Implant survival and prosthetic complications over time were evaluated. The study included SICs in premolar and molar regions made from monolithic lithium disilicate ceramic (M_LiDi) or veneered zirconia (V_ZiO) luted on a TBA documented over an observation time of at least 3 years. Survival and complication rates were calculated and compared by a log-rank test. Cox-Regressions were used to check potential predictors for the survival (p < .05).

RESULTS

Six hundred and one crowns out of 371 patients met the inclusion criteria and follow-up period was between 3.0 and 12.9 (mean: 6.4 (SD: 2.1)) years. Over time, six implants had to be removed and 16 restorations had to be refabricated. The estimated survival rates over 10 years were 93.5% for M_LiDi and 95.9% for V_ZiO and did not differ significantly among each other (p = .80). However, V_ZiO showed significantly higher complication rates (p = .003). Material selection, sex, age, and implant diameter did not affect the survival of investigated SICs but crown height influences significantly the survival rate (hazard ratio, HR = 1.26 (95%CI: 1.08, 1.49); p = .043).

CONCLUSIONS

Screw-retained SICs luted on TBAs that were fabricated from monolithic lithium disilicate ceramic or veneered zirconia showed reliable and similar survival rates. Increasing crown heights reduced survival over the years.

Immediate loading of definitive restorations in partially edentulous patients requiring an implant-supported prosthesis: A scoping review

STATEMENT OF PROBLEM

Interest is growing in immediately loading definitive implant-supported prostheses. However, it appears that implant protocols are evolving faster than their scientific validation.

PURPOSE

The purpose of this scoping review was to identify the current trends, feasibility, and clinical outcomes of a specific clinical loading scenario (type A), where a single definitive implant-retained restoration is delivered within 3 days. The focus question was "In partially edentulous patients requiring an implant-retained prosthesis (population), is immediate loading with a definitive restoration (concept) a viable treatment option (context)?"

MATERIAL AND METHODS

An electronic search was conducted in the PubMed, CENTRAL, Scopus, Embase, and Web of Science databases. Two authors independently reviewed the studies, screened titles and abstracts, and performed full-text analysis. Cross-reference checks within the bibliography of included studies, relevant reviews, and guideline were conducted. Bibliometric information and study details were extracted.

RESULTS

The search identified 2568 titles after removing duplicates. Four studies involving 91 participant and 100 implant-retained restorations were included in this scoping review. The selected articles were a randomized controlled trial (RCT), a prospective clinical study, and the remaining 2 were case series. The follow-up periods investigated ranged from 6 to 26 months. All studies evaluated marginal bone loss as a primary outcome, and only 1 implant failure was reported. Patient-reported outcome measures were favorable, and no major biological or technical complications were reported in any study.

CONCLUSIONS

Immediate loading with a definitive restoration within 3 days appears to be a suitable approach in specific clinical situations.

Group 2 ITI Consensus Report: Technological developments in implant prosthetics

OBJECTIVES

Group-2 reviewed the scientific evidence in the field of «Technology». Focused research questions were: (1) additive versus subtractive manufacturing of implant restorations; (2) survival, complications, and esthetics comparing prefabricated versus customized abutments; and (3) survival of posterior implant-supported multi-unit fixed dental prostheses.

MATERIALS AND METHODS

Literature was systematically screened, and 67 publications could be critically reviewed following PRISMA guidelines, resulting in three systematic reviews. Consensus statements were presented to the plenary where after modification, those were accepted.

RESULTS

Additively fabricated implant restorations of zirconia and polymers were investigated for marginal/internal adaptation and mechanical properties without clear results in favor of one technology or material. Titanium base abutments for screw-retained implant single crowns compared to customized abutments did not show significant differences concerning 1-year survival. PFM, veneered and monolithic zirconia implant-supported multi-unit posterior fixed dental prostheses demonstrated similar high 3-year survival rates, whereas veneered restorations exhibited the highest annual ceramic fracture and chipping rates.

CONCLUSIONS

For interim tooth-colored implant single crowns both additive and subtractive manufacturing are viable techniques. The clinical performance of additively produced restorations remains to be investigated. Implant single crowns on titanium base abutments show similar clinical performance compared to other type of abutments; however, long-term clinical data from RCTs are needed. The abutment selection should be considered already during the planning phase. Digital planning facilitates 3D visualization of the prosthetic design including abutment selection. In the posterior area, monolithic zirconia is recommended as the material of choice for multi-unit implant restorations to reduce technical complications.