Advanced and Readily-Available Wireless-Powered Blue-Light-Implant for Non-Invasive Peri-Implant Disinfection

Non-invasive light-based antibacterial therapy has a good prospect in non-surgical treatment of peri-implant infections. However, its applications are severely limited by poor penetration of light into human tissues, leading to unsatisfying outcomes. Moreover, as an essential prerequisite for traditional light therapy, lasers can no longer meet the patients' needs for convenient treatment at any time. To break through the spatial and temporal limitations of traditional light therapy, a wireless-powered blue-light zirconia implant for readily available treatment of peri-implant infection is proposed. In space, complete irradiation to complex peri-implant structure is realized by the built-in wireless-powered light source, thus improving the efficacy. In time, wireless-powering allows timely and controllable anti-infection treatment. Blue micro-light emitting diodes are used as therapeutic light sources, which effectively kill peri-implant infection-related bacteria without exogenous photosensitive agents. Porphyromonas gingivalis biofilm on implant surface can be completely killed after 20 min irradiation in vitro. The bactericidal rate of peri-implant methicillin-resistant Staphylococcus aureus infection reaches 99.96 ± 0.03% under 30 min per day blue light exposure in vivo. Within the scope of this study, the treatment of peri-implant infection with blue-light implant has preliminary feasibility, giving a new approach to non-invasive treatment of deep oral infections, including peri-implant infections.

Influence of Surface Treatment and Accelerated Ageing on Biaxial Flexural Strength and Hardness of Zirconia

The aim was to investigate how the surface treatment and the process of accelerated ageing of zirconia for dental implants affect the biaxial flexural strength and hardness. Zirconia discs with a diameter of 12.6 mm were subjected to either one of the following treatments: polishing (Zp); polishing and heat treatment at 1250 °C for 1 h (Zpt); machining (Zm); machining and heat treatment (Zmt); or sandblasting, acid-etching, and heat treatment (Z14) (n = 45 per group). Biaxial flexural strength and Martens hardness (HM) were measured without further treatment and after accelerated ageing for 5 h or 5 × 5 h according to ISO 13356 (n = 15 per group). Two-way ANOVA was applied to test the effect of surface treatment and ageing (α = 0.05). The reliability of the specimens was described with Weibull two-parameter distribution of biaxial flexural strength data. Overall, the surface treatment (p < 0.001) and ageing (p = 0.012) revealed a significant effect on biaxial flexural strength values, while HM was only affected by the surface treatment (p < 0.001) but not ageing (p = 0.160). Surface treatment significantly affected HM (p < 0.001) but not ageing (p = 0.160). The applied surface treatments affected the biaxial flexural strength and HM of zirconia. For accelerated ageing, a duration of both 5 h and 5 × 5 h is recommended to evaluate the effect of surface treatments. Zm was the most reliable surface as it was least affected by ageing and provided low standard deviations of biaxial flexural strength values.

Two-piece zirconia implants in the posterior mandible and maxilla: A cohort study with a follow-up period of 9 years

OBJECTIVES

Long-term follow-up observations of zirconia implants are rare. This study aimed at evaluating the clinical performance of two-piece zirconia implants in the posterior jaws over 9 years.

MATERIALS AND METHODS

Sixty partially edentulous patients were treated with two-piece zirconia implants. In eight no primary stability could be achieved. Fifty-two patients received the final restoration (i.e., cemented fibreglass abutments and all-ceramic crowns). After 2 years, 2 implants failed and 4 dropouts were recorded. The remaining 46 patients with one target implant each were recalled at 9 years. Besides implant survival, clinical parameters at the implant level (plaque index-PI, bleeding on probing-BOP, probing depth-PD, mucosal recession-MR) were recorded and compared with previously collected data. Mechanical and technical complications were assessed.

RESULTS

Thirty patients responded. The mean observation period was of 111.1 ± 2.2 months. One implant was lost. Data recorded from the remaining 29 implants were analysed. PI values increased overtime. Mean BOP and PD remained unchanged during follow-up. No additional cases of peri-implantitis were recorded over the 10 diagnosed during the first 2 years of follow-up. No significant changes in mean MR values were detected over time, with 65% of the all included implants exhibiting no recession at 9 years and all the others, but one, a maximum MR of 1 mm. Three technical and 6 mechanical complications occurred in 7 patients between 2- and 9-years (6.9% and 20.7%, respectively, at patient level).

CONCLUSION

Within the limitations of the present study, a high survival rate was registered. Albeit frequent mechanical and technical complications, two-piece zirconia implants could represent a valid solution for the replacement of single teeth in the posterior jaws.

Surface Structure of Zirconia Implants: An Integrative Review Comparing Clinical Results with Preclinical and In Vitro Data

Background: The purpose of this review was to analyze and correlate the findings for zirconia implants in clinical, preclinical and in vitro cell studies in relation to surface structure. Methods: Electronic searches were conducted to identify clinical, preclinical and in vitro cell studies on zirconia implant surfaces. The primary outcomes were mean bone loss (MBL) for clinical studies, bone-to-implant contact (BIC) and removal torque (RT) for preclinical studies and cell spreading, cell proliferation and gene expression for cell studies. The secondary outcomes included comparisons of data found for those surfaces that were investigated in all three study types. Results: From 986 screened titles, 40 studies were included for data extraction. In clinical studies, only micro-structured surfaces were investigated. The lowest MBL was reported for sandblasted and subsequently etched surfaces, followed by a sinter and slurry treatment and sandblasted surfaces. For BIC, no clear preference of one surface structure was observable, while RT was slightly higher for micro-structured than smooth surfaces. All cell studies showed that cell spreading and cytoskeletal formation were enhanced on smooth compared with micro-structured surfaces. Conclusions: No correlation was observed for the effect of surface structure of zirconia implants within the results of clinical, preclinical and in vitro cell studies, underlining the need for standardized procedures for human, animal and in vitro studies.

Immediate Restoration of Single-Piece Zirconia Implants: A Prospective Case Series-Long-Term Results after 11 Years of Clinical Function

OBJECTIVES

The aim of this prospective case series was to evaluate single-piece zirconia implants restored with lithium disilicate CAD/CAM crowns through a long-term follow-up.

METHODS

In this trial, 20 one-piece zirconia implants were placed in 20 patients. Implants were restored (i) immediately with lithium disilicate CAD/CAM provisionals, and (ii) permanently four months after surgery. Patients were followed for 11 years. Clinical parameters and radiological measurements of the zirconia implants were assessed. For the statistical analysis, paired t-test was applied.

RESULTS

Four implants were counted as implant failure due to the loss of implant stability, resulting in a Kaplan-Meier survival rate of 80% up to 11 years. The mean bleeding on probing values were 19.1% (SD ± 13.1) and 18.2% (SD ± 17.6) 96 and 11 years after implant placement, respectively. The plaque index revealed a significant decrease over time (p < 0.001) with a value between 25.9% (SD ± 5.7) and 12.6% (SD ± 10.0) at baseline and 11-years follow-up respectively. The marginal bone level revealed a significant decrease 4, 8, and 11 years after implant insertion (p = 0.001, p = 0.019, and p = 0.027, respectively).

CONCLUSIONS

Immediately loaded zirconia single-piece implants showed a suitable success rate in clinical and radiographic outcomes.

Biomechanical and Histological Analysis of Titanium (Machined and Treated Surface) Versus Zirconia Implant Materials: An In Vivo Animal Study

OBJECTIVES

The aim of this study was to perform an in vivo histological comparative evaluation of bone formation around titanium (machined and treated surface) and zirconia implants. For the present study were used 50 commercially pure titanium implants grade IV, being that 25 implants with a machined surface (TiM group), 25 implants with a treated surface (TiT group) and, 25 implants were manufactured in pure zirconia (Zr group). The implants (n = 20 per group) were installed in the tibia of 10 rabbits. The implants distribution was randomized (n = 3 implants per tibia). Five implants of each group were analyzed by scanning electron microscopy and an optical laser profilometer for surface roughness characterization. Six weeks after the implantation, 10 implants for each group were removed in counter-torque for analysis of maximum torque value. The remaining samples were processed, included in historesin and cut to obtain non-decalcified slides for histomorphological analyses and histomorphometric measurement of the percentage of bone-implant contact (BIC%). Comparisons were made between the groups using a 5% level of significance (p < 0.05) to assess statistical differences. The results of removal torque values (mean ± standard deviation) showed for the TiM group 15.9 ± 4.18 N cm, for TiT group 27.9 ± 5.15 N cm and for Zr group 11.5 ± 2.92 N cm, with significant statistical difference between the groups (p < 0.0001). However, the BIC% presented similar values for all groups (35.4 ± 4.54 for TiM group, 37.8 ± 4.84 for TiT group and 34.0 ± 6.82 for Zr group), with no statistical differences (p = 0.2171). Within the limitations of the present study, the findings suggest that the quality of the new bone tissue formed around the titanium implants present a superior density (maturation) in comparison to the zirconia implants.

Group 2 ITI Consensus Report: Prosthodontics and implant dentistry

OBJECTIVES

Working Group 2 was convened to address topics relevant to prosthodontics and dental implants. Systematic reviews were developed according to focused questions addressing (a) the number of implants required to support fixed full-arch restorations, (b) the influence of intentionally tilted implants compared to axial positioned implants when supporting fixed dental prostheses (FDPs), (c) implant placement and loading protocols, (d) zirconia dental implants, (e) zirconia and metal ceramic implant supported single crowns and (f) zirconia and metal ceramic implant supported FDPs.

MATERIALS AND METHODS

Group 2 considered and discussed information gathered in six systematic reviews. Group participants discussed statements developed by the authors and developed consensus. The group developed and found consensus for clinical recommendations based on both the statements and the experience of the group. The consensus statements and clinical recommendations were presented to the plenary (gathering of all conference attendees) and discussed. Final versions were developed after consensus was reached.

RESULTS

A total of 27 consensus statements were developed from the systematic reviews. Additionally, the group developed 24 clinical recommendations based on the combined expertise of the participants and the developed consensus statements.

CONCLUSIONS

The literature supports the use of various implant numbers to support full-arch fixed prostheses. The use of intentionally tilted dental implants is indicated when appropriate conditions exist. Implant placement and loading protocols should be considered together when planning and treating patients. One-piece zirconia dental implants can be recommended when appropriate clinical conditions exist although two-piece zirconia implants should be used with caution as a result of insufficient data. Clinical performance of zirconia and metal ceramic single implant supported crowns is similar and each demonstrates significant, though different, complications. Zirconia ceramic FDPs are less reliable than metal ceramic. Implant supported monolithic zirconia prostheses may be a future option with more supporting evidence.

Proceedings of the 6th ITI Consensus Conference

The 6th ITI Consensus Conference was held in Amsterdam on 17-19 April 2018. In preparation for the conference, 21 systematic reviews were written. They were divided into five main topics in dental implantology-surgery, prosthodontics, patient-reported outcomes, complications/risk and digital technologies. Based on these review papers, the working groups prepared consensus statements, clinical guidelines and recommendations for future research.

Performance of a New Al₂O₃/Ce-TZP Ceramic Nanocomposite Dental Implant: A Pilot Study in Dogs

Although titanium remains as the prevalent material in dental implant manufacturing new zirconia-based materials that overcome the major drawbacks of the standard 3Y-yttria partially-stabilized zirconia (Y-TZP) are now emerging. In this study, a new ceramic nanocomposite made of alumina and ceria-stabilized TZP (ZCe-A) has been used to produce dental implants with the mechanic and topographic characteristics of a pilot implant design to evaluate bone and soft tissue integration in a dog model (n = 5). Histological cross-section analysis of the implanted ceramic fixations (n = 15) showed not only perfect biocompatibility, but also a high rate of osseous integration (defined as the percentage of bone to implant contact) and soft tissue attachment. This clinical success, in combination with the superior mechanical properties achieved by this Al₂O₃/Ce-TZP nanocomposite, may place this material as an improved alternative of traditional 3Y-TZP dental implants.

Non-surgical treatment of peri-implant mucositis and peri-implantitis at zirconia implants: a prospective case series

OBJECTIVES

To assess the efficacy of non-surgical therapy for the management of peri-implant diseases at a two-piece zirconium implant system.

MATERIAL & METHODS

Thirty-four patients with 45 implants participated in this study. Seventeen patients (24 implants) were diagnosed with peri-implant mucositis and received mechanical debridement + local antiseptic therapy using chlorhexidine digluconate (MD + CXH), while 17 patients (21 implants) diagnosed with peri-implantitis were assigned to Er:YAG laser therapy. In both groups, post-operative maintenance care included supramucosal plaque removal and local pocket irrigation using CHX. The primary endpoint was defined as disease resolution at 6 months (i.e. absence of bleeding upon probing (BOP) at mucositis sites/absence of BOP and probing pocket depths (PD) ≥6 mm at peri-implantitis sites).

RESULTS

Resolution of peri-implant mucositis and peri-implantitis was obtained in 9/17 (52.9%) (p = 0.001) and 5/17 (29.4%) (p = 0.02) of the patients respectively.

CONCLUSION

Non-surgical treatment of either peri-implant mucositis using MD + CHX or peri-implantitis using ERL at zirconia implants was associated with significant short-term clinical improvements. A complete disease resolution, however, was not achieved in the majority of the patients.

All-Ceramic Single Crown Restauration of Zirconia Oral Implants and Its Influence on Fracture Resistance: An Investigation in the Artificial Mouth

The aim of the current investigation was to evaluate the fracture resistance of one-piece zirconia oral implants with and without all-ceramic incisor crowns after long-term thermomechanical cycling. A total of 48 implants were evaluated. The groups with crowns (C, 24 samples) and without crowns (N, 24 samples) were subdivided according to the loading protocol, resulting in three groups of 8 samples each: Group “0” was not exposed to cyclic loading, whereas groups “5” and “10” were loaded with 5 and 10 million chewing cycles, respectively. This resulted in 6 different groups: C0/N0, C5/N5 and C10/N10. Subsequently, all 48 implants were statically loaded to fracture and bending moments were calculated. All implants survived the artificial aging. For the static loading the following average bending moments were calculated: C0: 326 Ncm; C5: 339 Ncm; C10: 369 Ncm; N0: 339 Ncm; N5: 398 Ncm and N10: 355 Ncm. To a certain extent, thermomechanical cycling resulted in an increase of fracture resistance which did not prove to be statistically significant. Regarding its fracture resistance, the evaluated ceramic implant system made of Y-TZP seems to be able to resist physiological chewing forces long-term. Restauration with all-ceramic single crowns showed no negative influence on fracture resistance.

Peri-implant bone formation of non-thermal atmospheric pressure plasma-treated zirconia implants with different surface roughness in rabbit tibiae

OBJECTIVES

The aim of this study was to evaluate and compare the osseointegration of powder-injection molded (PIM) zirconia implants in rabbit tibiae with or without He plasma treatment.

MATERIAL AND METHODS

Twenty-five rabbits received 4 types of external hex implants with identical geometry in the tibiae: PIM zirconia implants, roughened PIM zirconia implants, plasma-treated PIM zirconia implants, and plasma-treated roughened PIM zirconia implants. The contact angles of the four types of implants were evaluated. Removal torque tests and histomorphometric analyses were performed.

RESULTS

The plasma treatment markedly enhanced the hydrophilicity, but did not seem to change the surface topography of the PIM zirconia implants. There were statistically significant differences in the bone-to-implant contact (BIC) ratios, bone volume (BV/TV), and removal torque values (RTQ) among the tested implant types (P < 0.001). The plasma-treated implants exhibited significantly higher BIC and BV/TV values than the untreated implants. However, the removal torque values favored the rough surface.

CONCLUSIONS

The He plasma treatments on PIM zirconia implants made the surface more hydrophilic and enhanced the osseointegration of the implants without changing the micro-topography.

Current findings regarding zirconia implants

PURPOSE

The present article aims to analyze the available clinical data on the survival and success rate of dental zirconia implants (ZI).

MATERIAL AND METHOD

Studies (2006-2011) listed in the bibliography were obtained by using the key words "zirconia, zirconium, implants, dental, clinical" and combinations of these in different databases and on the internet. These articles served as a basis for the article.

RESULTS

A total of 17 clinical studies were found, involving 1,675 implants and 1,274 patients. In 16 studies, one-piece implant systems were investigated. The survival rates for ZI range from 74-98% after 12-56 months, with success rates between 79.6-91.6% 6-12 months after prosthetic restoration. However, the design of most of the studies show considerable shortcomings, and only low evidence level.

CONCLUSION

The small number of studies and the limited period of observation permit only a qualified statement on the clinical success of ZI. The results available to date indicate that ZI are inferior to titanium implants (TI) with regard to survival and success rates. Well-conducted long-term studies are urgently needed to permit a meaningful assessment of the survival or success rates of ZI and a statement concerning their application as an alternative to TI.