Influence of implant location on the clinical outcomes of implant abutments: a systematic review and meta-analysis

Mechanical, Chemical, and Biological Properties of 3D-Printed Abutments: A Systematic Review

Aim:

A systematic review of the methods of 3D printing and the materials used so far for the manufacture of abutments was performed to evaluate whether their clinical use is indicated through the mechanical, chemical, and biological analyses carried out.

Materials and Methods:

An electronic search conducted by three independent reviewers was carried out in the PubMed, Web of Science, Cochrane Library, Science Direct, and Lilac databases. The inclusion criterion was researching articles in English that contained as subject the manufacturing of abutments through 3D printing/additive manufacturing. Any meta-analyses, reviews, book chapters, abstracts, letters, conferences papers, and studies without abutments printed were excluded.

Results:

We found 780 references, which after applying the exclusion criteria resulted in the final inclusion of seven articles for review. The studies had a high heterogeneity, showing different materials and methodologies to manufacture abutments, which makes a comparison between them difficult, and for this reason it was not possible to carry out a meta-analysis with the data found.

Conclusions:

Even with the limitations found in the present research, it is possible to conclude that printed abutments have adequate mechanical, chemical, and biological properties that can indicate their clinical use. 3D printing presents high accuracy and speed and can produce customized abutments according to each case.

Premature failure of a screw-retained ceramic single crown: A clinical report and fractographic analysis

Screw-retained implant-supported ceramic restorations have shown increased rates of technical complications compared with their cemented counterparts, including fracture and chipping of the ceramic structures. The present clinical report identified the causes leading to the catastrophic failure of a screw-retained lithium disilicate veneered crown cemented to a zirconia abutment with a titanium base by using a systematic fractographic approach. A combination of occlusal overloading, a deficient design and inadequate material selection was identified as being responsible for the fracture. These findings highlight the importance of a thorough analysis of the anatomic conditions and loading scenario of screw-retained implant-supported restorations.

Impact of implant location on the prevalence of peri-implantitis: A systematic review and meta- analysis

OBJECTIVES

To evaluate scientific evidence about the impact of implant location on the prevalence of peri-implantitis at implant level.

SOURCE

Databases (PubMed, Embase and Cochrane) were searched until March 2020without limitations on language or publication year. Hand searches and gray literature were also included.

STUDY SELECTION

Clinical studies reporting data on prevalence of peri-implantitis in anterior and posterior regions at implant level, and evaluations of implants with at least 1 year of function were selected.

DATA

Ten studies with a low risk of bias were included. Meta-analysis was performed to estimate the pooled risk ratio. A significantly higher prevalence of peri-implantitis in anterior region compared to posterior region was found (Risk ratio: 1.34; 95 % CI: [1.07, 1.69]; p = 0.01). Meta-regression was performed to analyze the potential influence of confounding factors by calculating p-value of the coefficient. Subjects (p = 0.827), implants (p = 0.859) and age (p = 0.656) did not significantly influence the outcome. Subgroup analysis by jaw revealed significantly higher prevalence of peri-implantitis in maxillary anterior (Risk ratio: 1.37; 95 % CI: [1.10, 1.71]; p = 0.005) and mandibular anterior (Risk ratio: 1.76; 95 % CI: [1.29, 2.42]; p = 0.0004) regions compared to maxillary posterior region. No significant difference was found between maxillary anterior and mandibular posterior (Risk ratio: 1.15; 95 % CI: [0.75, 1.75]; p = 0.53) regions. A meta-analysis was precluded between mandibular anterior and mandibular posterior regions due to high statistical heterogeneity (I ² = 76 %).

CONCLUSIONS

Implants in the maxillary anterior and mandibular anterior regions had a higher prevalence of peri-implantitis compared to the maxillary posterior region.

CLINICAL SIGNIFICANCE

Practitioners should strictly grasp the indications for patients missing anterior teeth and make comprehensive treatment planning.

Comparative evaluation of the wear resistance of two different implant abutment materials after cyclic loading – An in vitro study

Purpose:

To comparatively evaluate the wear resistance of two different implant abutment materials with titanium implants after cyclic loading.

Methodology:

Two groups utilizing 20 titanium implants secured in resin blocks, in which 10 titanium implants are connected with titanium abutments (Group I, n = 10) and the other 10 titanium implants are connected with Polyether ether Ketone (PEEK) abutments (Group II, n = 10). Abutments are cyclically loaded for 550,000 cycles. Surface profilometry, scanning electron microscopy (SEM), and energy-dispersive X-ray spectrometry (EDS) are carried out for all the abutment in both Group I and Group II before and after cyclic loading. The abutment surface at the implant-abutment interface is analyzed for wear.

Results:

On comparison using independent “t”-test, it was found that the mean difference values of pre- and post-cyclic loading surface roughness (Ra value) of Group I (premachined titanium straight abutments) (−0.073 μm) was lower than the Group II test samples (premachined PEEK straight abutments) (−0.0004 μm), and this was found to be statistically insignificant (P = 0.272). SEM micrographs and EDS results also corroborate with the results of surface profilometry.

Conclusion:

The new concept in this study is Group II (PEEK abutments) are connected with titanium implants, to prove its compatibility and aesthetics. Within the limitations of the study, the surface roughness values before and after cyclic loading of two different abutment materials revealed that the wear resistance of titanium abutments is more than PEEK abutments, but the difference was found to be statistically insignificant.

Zirconia implant abutments supporting single all-ceramic crowns in anterior and premolar regions: A six-year retrospective study

BACKGROUND

Clinical studies regarding zirconia implant abutments reported good survival rates in the short-term observation period. The purpose of this study was to assess the six-year clinical performance of zirconia abutments supporting all-ceramic crowns in anterior and premolar regions.

METHODS

The patients received zirconia implant abutments to support all-ceramic crowns in Chang-Gung Medical Center during the period August 2010 to August 2011 were enrolled. In the following six years of observation period after the implant-crown had finished, the clinical parameters of all of the included patients were registered on a special form. The records regarding the following variables: age, gender, implant location, the condition of edentulous site before implant placement, esthetic performance at baseline, presence or absence of technical complications, and biological outcomes were registered and scrutinized for evaluation.

RESULTS

Out of the 32 zirconia implant abutments and 32 all-ceramic crowns that were followed for six years. Neither abutments nor crowns were lost, yielding 100% survival rates for both zirconia abutments and crowns. The esthetic outcomes were excellent except that a score of 2 was given to two restorations. With regard to technical complications, there was one instance of abutment screw loosening, two cases of veneering ceramic chipping, one restoration with occlusal roughness, and three instances of crowns loosening. Overall, the success rates were 96.8% and 81.2% for abutments and crowns respectively. In biological performance, only 1 implant was classified in group II (satisfactory survival) in the Misch classification, while all the others were classified in group I (excellent).

CONCLUSIONS

Zirconia abutments supporting all-ceramic crowns demonstrated high survival rate, good biological and esthetic results. While some technical complications were frequently observed, the complication-free rates were 96.8% for abutments and 81.2% for crowns in the medium-term observation period.

The relationship between single nucleotide polymorphisms and dental implant loss: a scoping review

OBJECTIVES

The purpose of this review was to evaluate the relationship between genetic polymorphisms and dental implant loss.

MATERIALS AND METHODS

All case-control studies examining single nucleotide polymorphisms (SNPs) and dental implant failure were considered. A Boolean search was conducted on PubMed and Scopus to find eligible studies.

RESULTS

The initial search produced 78 results. Twenty-one studies were considered for inclusion after review and 16 were included in the final review. Twenty-two different polymorphisms were analyzed and statistically significant correlation was found for IL-4, IL-1A, IL-1B, MMP-8, and MMP-1 polymorphisms for dental implant failure.

DISCUSSION

A limited number of comprehensive studies have been done in this field. Additional studies with larger sample sizes and different ethnic backgrounds need to be done to see if the results can be reproduced. Of the polymorphisms studied, the IL-4 (+33), MMP-8 (-799), MMP-1 (-519), and MMP-1 (-1607) polymorphisms show the greatest association with dental implant loss.