Aim
The aim of this systematic review and meta‐analysis was to assess and compare peri‐implant marginal bone loss in cement‐ and screw‐retained prostheses.
Material and Methods
Electronic database ...and manual searches were undertaken to identify trials, prospective or retrospective studies reporting on radiographic marginal bone loss around dental implants restored with cement‐ and/or screw‐retained prostheses. Two reviewers independently conducted the article selection and data extraction. Random‐effects models were used to obtain estimates of peri‐implant marginal bone loss mean, 95% confidence intervals (CI).
Results
Of the 1217 identified studies, nine finally met the inclusion criteria. Only two studies included both cement‐ and screw‐retained prostheses, three assessed only screw‐retained prostheses, and four evaluated only cement‐retained prostheses. Pooled mean marginal bone loss was 0.53 mm (CI 95%, 0.31–0.76 mm) for cement‐retained prostheses and 0.89 mm (CI 95%, 0.45–1.33 mm) for screw‐retained prostheses.
Conclusion
There is no evidence to support differences in the marginal bone loss through indirect comparison between cement and screw‐retained restorations.
PURPOSETo find out the difference in the stresses induced by one-piece monophasic and two-piece dental implants supporting All-on-4 implant-supported prostheses using finite element analysis. ...MATERIALS AND METHODSTwo finite element maxillary models were designed: In the two-piece model, two-piece dental implants were used, and in the one-piece model, one-piece dental implants were used. The dental implants were placed according to the All-on-4 treatment concept. The anterior implants were axially placed; however, the posterior implants were placed with a distal inclination of 15 degrees. In each model, the prosthetic superstructure was designed to be a titanium implant prosthesis with zirconia crowns. Three loading scenarios were applied in this study. The first scenario simulated biting function with a total load of 250 N. The second scenario simulated incision function in which 90-N horizontal static load was applied to the palatal surface of central incisors. The third scenario simulated biting in the presence of a cantilever. RESULTSIn the three loading scenarios, the stresses were higher in the two-piece model. Higher stress values were recorded posteriorly rather than anteriorly in both models. CONCLUSIONOne-piece dental implants induce lower stress values compared with two-piece dental implants when used in All-on-4 implant-supported prostheses.
Objective
CAD‐CAM has dramatically advanced dental restorative procedures to include implant‐supported crowns. The purpose of this study was to compare the fracture resistance following mechanical ...loading and thermocycling of various screw‐retained and cement‐retained ceramic and polymethylmethacrylate material combinations using the TiBase abutment compared to PFM implant‐supported crowns.
Overview
Twelve implant restorations were fabricated for each of eight groups. Three groups were screw‐retained and five groups were cement‐retained implant restorations. The ceramic and polymethylmethacrylate restorations were fabricated on the TiBase abutment while the PFM restorations were fabricated on an UCLA abutment. Data were analyzed with a one way Analysis of Variance and Tukey's post‐hoc test to evaluate the effect of abutment and crown type on fracture load (alpha = 0.05). A significant difference was found in the maximum fracture load between groups (P < 0.001).
Conclusions
The screw‐retained implant restorations demonstrated higher fracture loads than their cement‐retained counterparts. The TiBase abutment compared favorably to the UCLA abutment.
Clinical Significance
The TiBase abutment is a titanium insert which combines the esthetics of a ceramic abutment with the mechanical properties of a titanium abutment and should be considered a viable clinical alternative to the conventional implant‐supported PFM crown based on theses in vitro results and in context of in vivo studies. The lithium disilicate hybrid abutment/crown implant‐supported restoration utilizing the TiBase abutment may be an ideal clinical choice due to simplicity, single appointment CAD‐CAM, and esthetics.
Purpose
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.
...Materials and Methods
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%.
Results
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.
Conclusions
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.
Objective: To evaluate the influence of the crown‐to‐implant ratio (C/I) ratio and different implant prosthetic treatment modalities on crestal bone loss around dental implants placed in the ...posterior region.
Material and methods: A total of 192 ITI dental implants were consecutively placed in premolars and molars of 83 partially edentulous patients. All implants were restored by means of ceramic‐to‐metal fused fixed partial dentures or a single crown. Patients were followed as part of a prospective longitudinal study focusing on implant success. Surgical, radiographic and clinical variables were collected at the 1‐year recall after implant placement and at the most recent clinical evaluation. Radiographic parameters were evaluated on periapical radiographs taken with a standardized long‐cone paralleling technique. Implant restorations were divided into three groups according to their respective clinical C/I ratios: (a) 0–0.99, (b) 1–1.99 and (c) ≥2.
Results: The mean clinical C/I ratio was 1.77±0.56 mm. A total of 51 implants (26.5%) showed a clinical C/I ratio equal to or greater than 2. In this group, three implants failed, giving a cumulative survival rate of 94.1%. Crestal bone loss was −0.34±0.27 mm in group a, −0.03±0.15 mm in group b and −0.02±0.26 mm in group c. Differences among groups were statistically significant (P=0.009). Mode of retention, splinting or presence of cantilever extensions did not have an effect on crestal bone loss around ITI dental implants.
Conclusions: Implant restorations with C/I ratios between 2 and 3 may be successfully used in the posterior areas of the jaw.
ABSTRACT
Background: Long‐term follow‐up studies (i.e., over 5 years), focusing on prosthetic outcomes and maintenance of implant‐supported reconstructions in the edentulous maxilla, are scarce in ...the literature.
Purpose: The purpose of this study was to evaluate and report 10‐year data on outcomes and maintenance of screw‐retained implant‐supported full‐arch casted titanium‐resin prostheses in the edentulous maxilla.
Materials and Methods: In the randomized control trial cohort of 24 patients, the outcome and maintenance of 23 bridges were registered.
Results: One patient dropped out of the study prior to the 10‐year control. Of the 23 remaining patients, 21 still had their original frameworks; one framework fractured after 8 years and one was remade after 7 years to create better support for the acrylic. The remaining 23 prostheses showed criteria of success, survival, and failure in 9, 82, and 9%, respectively. Tightening of two assembly screws was necessary in one patient. No detrimental effects were seen because of long cantilever extensions or opposing dentition. A total of 4.7 resin‐related complications per prosthesis were observed; tooth fracture was the most common prosthetic complication. There was an indication of greater prevention in the number of resin‐related complications with the use of lingual gold onlay compared with a resilient mouth guard, 0.71 and 1.67, respectively per bridge. The bridges were removed and reinserted 0.83 times per patient. No abutment or abutment screw fractures were registered.
Conclusion: Fracture or wear of the reconstruction materials were considered predictable risks when using resin‐based suprastructure materials. Status of opposing dentition and length of cantilevers did not confer additional risk. The use of a lingual gold onlay indicated prevention of resin‐related complications. Future research should focus on the suprastructure materials to predict better overall treatment results of implant‐supported full‐arch bridges in the edentulous maxilla.
The purpose of this article is to describe a technique to accurately cement implant crowns on an abutment extraorally and prevent misalignment that might change the desired position of the crown on ...the abutment when delivered. An implant-retained crown was tried-in and occlusal and interproximal contacts were adjusted for delivery. The cementation verification aid was fabricated using a polyvinylsiloxane bite registration material (Blu Mousse) to cement the crown onto the abutment extraorally to ensure proper alignment of the crown on the abutment. Cementation of the prosthesis occurred with no adjustments required to the interproximal or occlusal contacts during final delivery. This article provides a technique that aims to increase accuracy in the placement of the crown on the abutment when cementing screwmentable crowns.
With the help of dental implants, an oral rehabilitation can be performed not only very complex, but also very complete of various types of edentulous spaces. After insertion of the dental implants, ...they can be subsequently prosthetically restored through a wide range of implant-supported prosthetic restorations. In this material, we tried to highlight some particular aspects from the point of view of the laboratory stages of dental technique, which intervene in the technological flow of making implant-supported prosthetic restorations from ceramic masses on Zirconia structure.
Purpose
The purpose of this retrospective investigation was to evaluate the use of a prefabricated bar system for immediately loaded implants placed and restored according to the All‐on‐Four concept ...with up to 24‐month follow‐up.
Materials and Methods
A total of 51 patients (31 males and 20 females; mean age 63.4 years) presented with edentulous or partially edentulous jaws with severe atrophy of the posterior regions. All patients were treated with full‐arch fixed prostheses (28 maxillary, 34 mandibular) each supported by four implants (two vertical, two distally tilted). The implants were immediately loaded with screw‐retained full‐arch restorations. Each prosthesis was supported by a prefabricated metal bar combined with high‐density acrylic resin. Follow‐up visits were scheduled at 6, 12, and 24 months after initial prosthetic loading. Intraoral radiographs were obtained immediately after surgery and at each follow‐up visit by using a custom radiograph holder and parallel technique. Marginal bone levels were assessed using digital image analysis. Implant and prosthetic survival and success rates were evaluated. Patient satisfaction was further assessed using a 100‐mm visual analog scale (VAS). Data were compared by means of the Mantel‐Haenszel test.
Results
No drop‐outs occurred. The overall implant survival rates were 100% and 98.38% for the vertical and tilted implants respectively. Two of the 62 definitive fixed prostheses were lost during the observation period due to implant failure. Since restoration replacement due to implant failure was not judged a prosthodontic failure according to the survival criteria provided in this study, the overall prosthetic survival rate was 100%. No statistically significant differences in marginal bone levels between vertical and tilted implants were detected at 24‐month follow‐up evaluation in either jaw. All participants were functionally and esthetically satisfied with their definitive restorations after 2 years functioning, as confirmed by the average VAS scores (masticatory function: 99.7; phonetic function: 99.5, esthetics: 99.2).
Conclusions
The preliminary 24‐month results indicate that immediate loading of vertical and tilted implants using the evaluated prefabricated bar system may be a viable solution for edentulous jaw rehabilitation; however, more long‐term prospective clinical trials are needed to affirm the effectiveness of this surgical‐prosthetic protocol.
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