An XPS and SEM evaluation of six chemical and physical techniques for cleaning of contaminated titanium implants

Surface decontamination of explanted peri-implantitis-affected implants

AIM

The present study aimed at evaluating the effect of air-polishing (AP) and a combination of AP and alkaline electrolysed water (AEW) in surface decontamination of explanted peri-implantitis-affected implants.

MATERIALS AND METHODS

Twenty-five patients with 34 dental implants scheduled for explantation due to severe peri-implantitis were included. Following implant removal, the apical part of each implant was embedded in acrylic blocks. Implants were randomly allocated to surface decontamination using AP with or without AEW. Four implants were left untreated and used as negative controls. Specimens were analysed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Area of residual bacteria was the primary outcome.

RESULTS

SEM analysis revealed that both treatment protocols were effective in biofilm removal and only small proportions of target areas of the implants showed residual bacterial or mineralized deposits. Although differences between the treatment protocols were small, implant thread loci (top/flank/valley), zones of the implant (apical/middle/coronal), implant surface characteristics and gender influenced the results. In addition, EDS analysis showed that zones influenced the atomic% of carbon and calcium and that implant surface characteristics affected the atomic% of titanium.

CONCLUSIONS

AP, with or without AEW, is an effective method in removing biofilm from peri-implantitis-affected implants.

Influence of eight debridement techniques on three different titanium surfaces: A laboratory study

OBJECTIVES

Debridement methods may damage implant surfaces. This in vitro study investigated eight debridement protocols across three implant surfaces to assess both biofilm removal and surface alterations.

MATERIAL AND METHODS

One hundred sixty commercially pure titanium discs were treated to simulate commercially available titanium implant surfaces-smooth, abraded and abraded and etched. Following inoculation with whole human saliva to create a mixed species biofilm, the surfaces were treated with eight debridement methods currently used for clinical peri-implantitis (n = 10). This included air abrasion using powders of glycine, sodium bicarbonate and calcium carbonate; conventional mechanical methods-piezoelectric scaler, carbon and stainless steel scalers; and a chemical protocol using 40% citric acid. Following treatment, remaining biofilm was analysed using scanning electron microscopy and crystal violet assays. For statistical analysis, ANOVA was applied (p < 0.05).

RESULTS

All debridement techniques resulted in greater than 80% reduction in biofilm compared with baseline, irrespective of the surface type. Glycine powder delivered through an air polishing system eliminated the most biofilm. Mechanical instruments were the least effective at eliminating biofilm across all surfaces and caused the greatest surface alterations. Citric acid was comparable with mechanical debridement instruments in terms of biofilm removal efficacy. Titanium surfaces were least affected by air abrasion protocols and most affected by mechanical methods.

CONCLUSIONS

Mechanical protocols for non-surgical debridement should be approached with caution. Glycine powder in an air polisher and 40% citric acid application both gave minimal alterations across all implant surfaces, with glycine the superior method in terms of biofilm removal.

Photodynamic Therapy for Peri-Implant Diseases

Peri-implant diseases are frequently presented in patients with dental implants. This category of inflammatory infections includes peri-implant mucositis and peri-implantitis that are primarily caused by the oral bacteria that colonize the implant and the supporting soft and hard tissues. Other factors also contribute to the pathogenesis of peri-implant diseases. Based on established microbial etiology, mechanical debridement has been the standard management approach for peri-implant diseases. To enhance the improvement of therapeutic outcomes, adjunctive treatment in the form of antibiotics, probiotics, lasers, etc. have been reported in the literature. Recently, the use of photodynamic therapy (PDT)/antimicrobial photodynamic therapy (aPDT) centered on the premise that a photoactive substance offers benefits in the resolution of peri-implant diseases has gained attention. Herein, the reported role of PDT in peri-implant diseases, as well as existing observations and opinions regarding PDT, are discussed.

Mechanical removal of biofilm on titanium discs: An in vitro study

The objective of this in vitro study was to evaluate surface cleanness and cytocompatibility following mechanical instrumentation of biofilm-contaminated titanium surfaces. Titanium discs (non-modified [Ti(s)] and shot-blasted surfaces [Ti(r)]) contaminated with Streptococcus gordonii were instrumented using four different techniques: (i) gauze soaked in saline (GS), (ii) ultra-sonic device (US), (iii) rotating nickel-titanium brush (TiB), or (iv) air-polishing device (AP). Non-contaminated, untreated titanium disks were used as controls (C). Residual deposits and cytocompatibility for osteoblast-like cells were evaluated using scanning electron microscopy, immunofluorescence, and reverse transcriptase polymerase chain reaction. While the number of residual bacteria on Ti(s) discs was close to 0 in all treatment groups, significantly higher mean numbers of residual bacteria were observed on Ti(r) discs for GS (152.7 ± 75.7) and TiB (33.5 ± 22.2) than for US (0) and AP (0). Instrumentation with US resulted in deposition of foreign material (mean area% of foreign material: 3.0 ± 3.6% and 10.8 ± 9.6% for Ti(s) and Ti(r) discs, respectively). AP was the most effective decontamination procedure in reducing bacteria without depositing residual foreign material on Ti(r) discs. TiB and AP were superior methods in restoring cytocompatibility, although no method of mechanical decontamination resulted in pristine levels of cytocompatibility.

Research: Fluorescence Microscopy-Based Protocol for Detecting Residual Bacteria on Medical Devices

Standard methods are needed to reliably and efficiently assess bacterial contamination of processed medical devices. This article demonstrates a standard operating procedure (SOP) for fluorescence microscopy-based detection of residual bacteria on medical devices (BAC-VIS). BAC-VIS uses a 4',6-diamidino-2-phenylindole (DAPI) stain with fluorescent microscopy to quickly and cost-effectively detect bacterial contamination of processed medical device parts. The BAC-VIS protocol was optimized and achieved greater than 80% staining efficiency and a signal-to-noise ratio of more than 20 using four representative organisms. The SOP was first validated for use on a buildup biofilm model, accessory channels of contaminated clinically used devices, and inoculated endoscope end caps and O-rings. The buildup biofilm model was used to evaluate BAC-VIS after repeated treatment of adherent bacteria with three common high-level disinfectants: glutaraldehyde, ortho-phthalaldehyde, and peracetic acid. Next, BAC-VIS was used to assess clinically used endoscope parts that cultured positive for Gram-negative bacteria. DAPI-stained cells were found on all culture-positive devices, especially in grooves and imperfections on the surface. Finally, BAC-VIS was used to detect bacteria on inoculated endoscope device components. The results showed potential for BAC-VIS to be a valuable tool for industry and academic/medical researchers for investigations of contaminated medical devices. Results obtained using BAC-VIS can increase understanding of the role of design in cleanability, wear, and prevention of contamination and may lead to improvements in materials and design that could make processed endoscope use safer for patients. Of note, this protocol is not for detecting bacteria on scopes or scope parts that will be put back into clinical use.

A novel guided surgery system with a sleeveless open frame structure: a retrospective clinical study on 38 partially edentulous patients with 1 year of follow-up

Background

This retrospective clinical study aims to present results of experience with a novel guided surgery system with a sleeveless, open-frame structure, in which the surgical handpiece (not the drills used for preparation) is guided.

Methods

This study was based on an evaluation of the records of partially edentulous patients who had been treated with a sleeveless open-frame guided surgery system (TWIN-Guide®, 2Ingis, Brussels, Belgium), between January 2015 and December 2017. Inclusion criteria were patients with good systemic/oral health and a minimum follow-up of 1 year. Exclusion criteria were patients who had been treated without a guide, or with a guide with sleeves, patients with systemic/oral diseases and who did not have a follow-up of 1 year. The main outcomes were surgical (fit and stability of the surgical guide, duration of the intervention, implant stability, and any intra-operative or immediate post-operative complication), biologic, and prosthetic.

Results

Thirty-eight patients (24 males, 14 females; mean age 56.5 ± 14.0 years) were included in the study. These patients had been treated with 110 implants inserted by means of 40 sleeveless, open-frame guides. With regard to fit and stability, 34 guides were excellent, 4 acceptable, and 2 inadequate for use. The mean duration of the intervention was 23.7 (± 6.7) minutes. Immediately after placement, 2 fixtures were not stable and had to be removed. Two patients experienced pain/swelling after surgery. The 108 surviving implants were restored with 36 single crowns and 32 fixed partial prostheses (24 two-unit and 8 three-unit bridges); these restorations survived until the 1-year follow-up, with a low incidence of biologic and prosthetic complications.

Conclusions

Within the limits of this study, this novel guided surgery system with sleeveless, open frame–structure guides seems to be clinically reliable; further studies on a larger sample of patients are needed to confirm these outcomes.

In vitro Assessment of Peri-implantitis Treatment Procedures: A Review

Background:

The prevalence of peri-implantitis is increasing continuously and such a biological complication significantly decreases implant survival and success. Although various treatment modalities have been identified for peri-implantitis, no completely efficient method has yet been established.

Objective:

The aim of this review was to evaluate the scientific literature regarding the in vitro effects of peri-implantitis treatment.

Methods:

A review of the literature was performed by using Google Scholar, PubMed/ MEDLINE and Science Direct databases. In vitro studies on peri-implantitis treatment modalities were selected. The search strategy identified 57 eligible studies. After selection, 21 articles met all the inclusion criteria and were included in the present review.

Results:

Included in vitro studies evaluated different types of peri-implantitis treatment modalities such as mechanical, chemical, combination and laser therapies. Combination therapies with the aid of adjuvants were found to be more effective compared to the studies that used only one type of treatment modality. Laser systems were also tested and displayed interesting results in terms of surface decontamination with a variability associated with selected parameters.

Conclusion:

This review was performed to evaluate the efficacy of the treatment modalities used for peri-implantitis in vitro. Although there are various effective treatment methods, none has been completely successful in removing the biofilms related to peri-implantitis. The findings imply the need for further studies to develop more effective antimicrobial treatment procedures.

Thermal Testing of Titanium Implants and the Surrounding Ex-Vivo Tissue Irradiated With 9.3um CO2 Laser

PURPOSE

To measure the temperature rise and surface damage of titanium dental implants and the surrounding tissue in a pig jaw during 9.3-μm carbon dioxide (CO2) laser irradiation at various durations of time.

MATERIALS AND METHODS

Thermal analysis tests were performed on 12 implants with the same surface. Twelve implants mounted alone or in pig jaws were laser-irradiated with a 9.3-μm CO2 laser using 3 different power settings. The temperature of the implant body and the proximal tissues was measured with a J-Type Thermocouple after being laser-irradiated with 3 different power setting for 30, 60 seconds, and 2 minutes. Scanning electron microscope (SEM) and digital microscope images were also taken of the all the implants before and after laser irradiation to detect the presence or absence of surface damage.

RESULTS

Temperature analysis showed that in all cases the implant and the proximal tissue temperatures remained around the start temperatures of the implant and tissues with fluctuations of ±3°C but never reached the upper threshold of 44°C, the temperature at which thermal injury to bone has been reported. Digital and SEM images that were taken of the implants showed an absence of surface damage at the cutting speed of 20% (0.7 W); however, cutting speeds of 30% to 100% (1.0-4.2 W) did yield surface damage.

CONCLUSIONS

Laser irradiation of titanium implant surfaces using a 9.3-μm carbon dioxide laser with an average power of 0.7 W showed no increase in thermal temperature of the implant body and tissue temperatures as well as no evidence of implant surface damage.

Effects of air abrasive decontamination on titanium surfaces: A systematic review of in vitro studies

BACKGROUND

Air abrasion (AA) is one of the decontamination methods that have demonstrated promising results in treating peri-implant diseases.

PURPOSE

This systematic review aimed at evaluating the in vitro effect of AA on surface change, cleaning efficacy, and biocompatibility of titanium surfaces and at comparing it with other decontamination methods.

MATERIALS AND METHODS

A comprehensive search was conducted up to April 2018 using PubMed, Scopus, and Google Scholar databases to identify studies on the decontamination effect of AA. All types of titanium surfaces, abrasive powders, contaminated surfaces, and measuring methods were included.

RESULTS

Overall, 1502 articles were identified. After screening the titles and abstracts, and carefully reading the full-texts, 48 articles published between 1989 and 2018 were selected. AA was considered almost safe, particularly for the nonmodified surfaces. Nevertheless, harder powders such as sodium bicarbonate tended to damage the surface more than glycine. AA resulted in surface change similar to plastic curettes and Er: YAG lasers. Regarding the cleaning efficacy, there was no significant difference between glycine and sodium bicarbonate, but different mixtures of calcium phosphate, hydroxyapatite, and erythritol were superior to glycine. AA was superior or equal to all other decontamination methods in cleaning. Regarding biocompatibility, AA was more successful in preserving biocompatibility for noncontaminated surfaces compared with contaminated surfaces and when used with erythritol and osteoinductive powders.

CONCLUSIONS

AA can efficiently remove contamination without serious damage to the surface. The main drawback of the AA method seems to be its limitation in restoring the biocompatibility of the surface.

Failure load and stress analysis of orthodontic miniscrews with different transmucosal collar diameter

Miniscrews have been introduced in orthodontics as temporary anchorage devices (TADs), in order to move the correct teeth and avoid other elements to slide toward a wrong direction. Moreover the ease of use of TADs encouraged clinicians to use miniscrews also for non-conventional purposes, as fixation in mandibular fracture, mini-implant supported temporary pontics, miniscrew-assisted rapid palatal expanders and distalizers. These applications develop higher forces, so TAD fracture can be an unwanted complication. Some authors analyzed torsional loads but no studies measured forces required to bend the screws and ultimate flexural strength. Accordingly, in the present report, Ti-6Al-4V TADs were mechanically evaluated. Seven different diameters of screws were tested: 1.3 mm (Aarhus Screw, Medicon), 1.5 mm (Spider Screw, HDC), 1.6 mm (Aarhus Screw, Medicon), 1.7 mm (Ortho Easy, Forestadent), 1.8 mm (Ortho Implant, 3 M), 1.9 mm (Spider Screw, HDC) and 2.0 mm (Storm, Kristal). The forces to bend the titanium TADs were measured at 0.1 mm, 0.2 mm magnitude of deflections and at maximum load (as peak before screw fracture) in air with a universal testing machine. Statistical analyses were performed. Both at 0.1 mm and at 0.2 mm deflections and at maximum load, the significantly highest forces were reported with 1.7, 1.8, 1.9, and 2.0 mm TADs. The lowest values were reported with 1.6, 1.5, and 1.3 mm mini-implants. No significant differences were reported between 1.6 mm and 1.7 mm screws. It was found that load values in N versus stress in MPa were not fully comparable when screws with small and larger diameter were compared. Therefore, when placing a miniscrew for applications that need maximum shear bending resistance, these results would be considered in order to reduce risk of unwanted fracture.

Cleaning effect of osteoconductive powder abrasive treatment on explanted human implants and biofilm-coated titanium discs

The aim of this study is to test the cleaning effect and surface modification of a new implant surface treatment on explanted dental implants and titanium discs. It is a modified air powder abrasive (APA) treatment applied using osteoconductive powders. Twenty-eight in vitro Ca-precipitated organic film-coated titanium discs and 13 explanted dental implants were treated. In a 2-step approach, 3 powders were used: hydroxylapatite (HA) and biomimetic calcium phosphate (BioCaP), which are osteoconductive, and erythritol, which is not. APA treatment was applied. (Air pressure: 2.4 bar; water flow for cleaning: 41.5 ml/min, for Coating 1: 2.1 ml/min, and for Coating 2: 15.2 ml/min.) The test groups were as follows: Group 1: HA cleaning + BioCaP Coating 1; Group 2: HA cleaning + BioCaP Coating 2; Group 3: erythritol cleaning + BioCaP Coating 1; Group 4: erythritol cleaning + BioCaP Coating 2; Group 5: HA cleaning; Group 6: erythritol cleaning; and control: no powder. Cleaned areas were calculated by point counting method. Surface changes and chemical content were evaluated using light microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Cleaning effect between groups was compared by a pairwise Student's t test. The significance level was fixed at p < .05. Cleaning effect on the discs was 100% in all test groups and 5% in the control. Powder particles in varying size and shape were embedded on the surface. All HA- or CaP-treated surfaces showed Ca and P content but no surface damage. Calcified biofilm remnants were removed from the implant surface by the test groups, whereas in control groups, they remained. APA treatment with CaP and HA powders under clinically applicable pressure settings gives positive results in vitro; therefore, they could be promising when used in vivo.

Re-establishment of Biocompatibility of the In Vitro Contaminated Titanium Surface Using Osteoconductive Powders With Air-Abrasive Treatment

To achieve re-osseointegration on implant surfaces exposed to peri-implant infections, treatment should re-establish biocompatibility. The aim of this study was to test whether air powder abrasive treatment (APA) using osteoconductive powders can, in addition to cleaning, increase the biocompatibility of the contaminated implant surface. Ninety-six in vitro Ca-precipitated, organic film layer-coated sandblasted and acid-etched titanium discs were treated by APA using erythritol, hydroxylapatite (HA), and biocalcium phosphate (BioCaP) powders (n = 16 per group). Six treatment modalities were created (HA or erythritol cleaning with/without BioCaP coating). MC3T3-E1cells were seeded on discs, and cell attachment, viability, proliferation, and differentiation were evaluated. Pristine discs were used as control (control 1). Contaminated and nontreated discs were used as control (control 2). The cells were stretched and attached in all test groups. The cell viability and proliferation (DNA amount) in all test groups were significantly higher than in the pristine and contaminated disc groups. There was no significant difference between the test groups. The differentiation (alkaline phosphatase activity) of the cells on treated discs was significantly higher than on the contaminated discs but lower than in the pristine group. The cell viability in control 2 was significantly lower than the control 1. The APA with osteoconductive powder on contaminated titanium surfaces promoted the cell viability, proliferation, and differentiation of the MC3T3-E1 cells. The biocompatibility of the surface was higher than that of the contaminated discs. The tested aspects of cell response, with the exception of differentiation, reached to the level of the pristine surface. The in vitro results showed that APA with osteoconductive powders could be a promising method for implant surface treatment.

The effects of diode laser on Staphylococcus aureus biofilm and Escherichia coli lipopolysaccharide adherent to titanium oxide surface of dental implants. An in vitro study

Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This in vitro study aims at providing the experimental basis for possible use of diode laser (λ 808 nm) in the treatment of peri-implantitis. Staphylococcus aureus biofilm was grown for 48 h on titanium discs with porous surface corresponding to the bone-implant interface and then irradiated with a diode laser (λ 808 nm) in noncontact mode with airflow cooling for 1 min using a Ø 600-μm fiber. Setting parameters were 2 W (400 J/cm²) for continuous wave mode; 22 μJ, 20 kHz, 7 μs (88 J/cm²) for pulsed wave mode. Bactericidal effect was evaluated using fluorescence microscopy and counting the residual colony-forming units. Biofilm and titanium surface morphology were analyzed by scanning electron microscopy (SEM). In parallel experiments, the titanium discs were coated with Escherichia coli lipopolysaccharide (LPS), laser-irradiated and seeded with RAW 264.7 macrophages to quantify LPS-driven inflammatory cell activation by measuring the enhanced generation of nitric oxide (NO). Diode laser irradiation in both continuous and pulsed modes induced a statistically significant reduction of viable bacteria and nitrite levels. These results indicate that in addition to its bactericidal effect laser irradiation can also inhibit LPS-induced macrophage activation and thus blunt the inflammatory response. The λ 808-nm diode laser emerges as a valuable tool for decontamination/detoxification of the titanium implant surface and may be used in the treatment of peri-implantitis.

Leakage evaluation of original and compatible implant-abutment connections: In vitro study using Rhodamine B

Leakage has been addressed as a major contributing factor to inflammatory reactions at the implant–abutment connection, leading to problems such as oral malodor, inflammation, and marginal bone loss. The aim of this study was to investigate in vitro the leakage at implant–abutment interface of OsseoSpeed™ implants connected to original and compatible abutments. A total of 28 OsseoSpeed implants were divided into four groups (n = 7). Each group was connected to four different abutments according to manufacturers’ recommendations: group A (TiDesign™); group B (Natea™); group C (Dual™); and group D (Implanet™) abutments. The inner volume of each implant–abutment combination was calculated and leakage was detected for each group with spectrophotometric analysis at 1 h (D0) and 48 h (D1) of incubation time using Rhodamine B. At 1 h, leakage volume was significantly lower in TiDesign and Dual than in Natea and Implanet (P < 0.001). At 48 h, however, leakage was significantly lower between TiDesign and all other systems (P < 0.005). Compatible abutments do not fit internal connection of OsseoSpeed implants perfectly, which increases the leakage of the final assembly.

Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process

BACKGROUND

It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface.

METHODS

C. albicans biofilms were developed for 72 h on PMMA resin specimens (n = 168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey's Honestly Significant Difference (HSD) test (α = 0.05).

RESULTS

Immediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p < 0.01). However, after 48 h, both CT groups (CT5 and CT8) showed biofilm recolonization (p < 0.01). Residual biofilm recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p < 0.01).

CONCLUSION

Citric acid denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this CT did not prevent biofilm recolonization.

Detoxification of Implant Surfaces Affected by Peri-Implant Disease: An Overview of Non-surgical Methods

Objective:

The aim of this review is to summarize the findings of studies that have evaluated non-surgical approaches for detoxification of implant body surfaces in vitro and in vivo, and to evaluate clinical trials on the use of these methodologies for treating peri-implant disease.

Materials and methods:

A literature search was conducted using MEDLINE (Pubmed) from 1966 to 2013. In vitro and in vivo studies as well as clinical trials on non-surgical therapy were evaluated. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters including probing depth, clinical attachment levels, bleeding on probing; radiographic bone fill and histological re-osseointegration.

Results:

From 134 articles found 35 were analyzed. The findings, advantages and disadvantages of using lasers as well as mechanical and chemical methods are discussed. Most of the in vivo and human studies used combination therapies which makes determining the efficacy of one specific method difficult. Most human studies are case series with short term longitudinal analysis without survival or failure reports.

Conclusion:

Complete elimination of the biofilms is difficult to achieve using these approaches. All therapies induce changes of the chemical and physical properties of the implant surface. Re-osseointegration may be difficult to achieve if not impossible without surgical access to ensure thorough debridement of the defect and detoxification of the implant surface. Combination protocols for non-surgical treatment of peri-implantitis in humans have shown some positive clinical results but long-term evaluation to evaluate the validity and reliability of the techniques is needed.

In vitro evaluation of leakage at implant-abutment connection of three implant systems having the same prosthetic interface using rhodamine B

Objectives. Hollow space between implant and abutment may act as reservoir for commensal and/or pathogenic bacteria representing a potential source of tissue inflammation. Microbial colonization of the interfacial gap may ultimately lead to infection and bone resorption. Using Rhodamine B, a sensitive fluorescent tracer dye, we aim in this study to investigate leakage at implant-abutment connection of three implant systems having the same prosthetic interface. Materials and Methods. Twenty-one implants (seven Astra Tech, seven Euroteknika, and seven Dentium) with the same prosthetic interface were connected to their original abutments, according to the manufacturers' recommendation. After determination of the inner volume of each implant systems, the kinetic quantification of leakage was evaluated for each group using Rhodamine B (10⁻² M). For each group, spectrophotometric analysis was performed to detect leakage with a fluorescence spectrophotometer at 1 h (T0) and 48 h (T1) of incubation time at room temperature. Results. Astra Tech had the highest inner volume (6.8 μL), compared to Dentium (4 μL) and Euroteknika (2.9 μL). At T0 and T1, respectively, the leakage volume and percentage of each system were as follows: Astra Tech 0.043 μL or 1.48% (SD 0.0022), 0.08 μL or 5.56% (SD 0.0074), Euroteknika 0.09 μL or 6.93% (SD 0.0913), 0.21 μL or 20.55% (SD 0.0035), and Dentium 0.07 μL or 4.6% (SD 0.0029), 0.12 μL or 10.47% (SD 0.0072). Conclusion. The tested internal conical implant-abutment connections appear to be unable to prevent leakage. In average, Astra Tech implants showed the highest inner volume and the least leakage.

Detoxification of implant surfaces affected by peri-implant disease: an overview of surgical methods

Purpose. Peri-implantitis is one of the major causes of implant failure. The detoxification of the implant surface is necessary to obtain reosseointegration. The aim of this review was to summarize in vitro and in vivo studies as well as clinical trials that have evaluated surgical approaches for detoxification of the implant body surfaces. Materials and Methods. A literature search was conducted using MEDLINE (PubMed) from 1966 to 2013. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters, radiographic bone fill, and histological reosseointegration. Results. From 574 articles found, 76 were analyzed. The findings, advantages, and disadvantages of using mechanical, chemical methods and lasers are discussed. Conclusions. Complete elimination of the biofilms is difficult to achieve. All therapies induce changes of the chemical and physical properties of the implant surface. Partial reosseointegration after detoxification has been reported in animals. Combination protocols for surgical treatment of peri-implantitis in humans have shown some positive clinical and radiographic results, but long-term evaluation to evaluate the validity and reliability of the techniques is needed.

The effects of mechanical instruments on contaminated titanium dental implant surfaces: a systematic review

OBJECTIVE

The objective of this systematic review was to evaluate the ability of mechanical instruments to clean contaminated implant titanium surfaces.

MATERIALS AND METHODS

MEDLINE, Cochrane-CENTRAL and EMBASE databases were searched up to May 2013 to identify controlled studies on the cleaning efficacy of mechanical instruments on contaminated titanium surfaces.

RESULTS

A comprehensive search identified 1893 unique potential papers. Fourteen studies met the inclusion criteria and were selected for this systematic review. Most of the studies were in vitro studies. Different surfaces and different contamination methods were used. Most studies used titanium discs, strips and cylinders. The air abrasive was the treatment mostly evaluated. The available studies had a high heterogeneity that precluded any statistical analysis of the data. Therefore, the conclusions are not based on quantitative data. Non-metal curettes and rubber cups were found to be ineffective. Positive results were reported for (ultra)sonic scalers with a metal tip on polished surfaces, (ultra)sonic scalers with a non-metal tip on smooth and sand-blasted and acid-etched (SLA) surfaces, metal curettes and rotating titanium brushes on SLA surfaces. The air abrasive was found to be effective in cleaning machined, SLA and titanium plasma-sprayed (TPS) surfaces.

CONCLUSION

The available data suggest that the air abrasive may remove plaque effectively from machined, SLA and TPS titanium surfaces. Positive results were also observed for rotating titanium brushes on SLA surfaces and ultrasonic scalers with non-metal tip on polished and SLA surfaces. However, the clinical impact of these findings requires further clarification.

Chemical debridement of contaminated titanium surfaces: an in vitro study

OBJECTIVE

To compare the efficacy of different chemical solutions when used for chemical debridement of biofilm contaminated titanium surfaces in an in-vitro experimental study.

MATERIALS AND METHODS

Commercially pure titanium discs with a diameter of 6.2 mm and height of 2 mm, mirror-polished with a measured surface amplitude value SA = 0.037 μm ± 0.009 were used as test-surfaces. A biofilm was simulated with multi-layers of Staphylococcus epidermidis ATCC359844 covering the entire titanium surface. The chemical agents tested were: 3% H2O2, 0.2% Chlorhexidine, 24% EDTA-gel, 3% H2O2 mixed with 1.6 g/L TiO2 and sterile saline solution. The decontamination effect was evaluated by optical density analysis using spectrophotometry and with scanning electron microscopy (SEM) images of the remaining biofilm.

RESULTS

The suspensions of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone were the most effective in removing S. epidermidis biofilms (p < 0.05), whereas 0.2% chlorhexidine or 24% EDTA gel had no significant effects. SEM images of the remaining biofilms supported the quantitative results indicating the higher efficacy of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone. It also revealed that EDTA, despite a non-significant effect on reducing the amount of established biofilms, was able to alter the biofilm architecture, as demonstrated by increased interspaced regions.

CONCLUSIONS

In this in vitro study the decontamination potential of a suspension of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone were encouraging. Whether such procedures would have a similar effect in vivo remains to be determined.

Cleaning and modification of intraorally contaminated titanium discs with calcium phosphate powder abrasive treatment

OBJECTIVE

The aim of this study was to evaluate the cleaning efficiency on intraorally contaminated titanium discs by using calcium phosphate and air powder abrasive (APA) treatment. The modification of titanium surface (SLA) was evaluated and compared with the conventional air powder abrasive methods and phosphoric acid. This treatment modality might give new perspectives for peri-implant surface treatment.

MATERIALS AND METHODS

A total of 36 SLA surface titanium discs were kept in the human mouth for 48 h by 14 volunteers. The intraorally contaminated discs were stained with erythrosine dye to make the biofilm visible. Discs were randomly assigned to one of the six groups: APA without powder-only water and air (Control). APA with Hydroxylapatite (HA). APA with Hydroxylapatite and Calcium Phosphate (HA + TCP). APA with Titanium Dioxide (TiO2). APA with EMS Soft Subgingival powder (EMS). Phosphoric Acid. Light microscope photos were taken during the treatment. Following the cleaning, the residual biofilm, surface changes, and surface chemical content were evaluated using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). A systematic random sampling protocol and a point counting method were applied for the quantitative evaluation of the remaining biofilm. Multiple comparisons within and between groups are performed by Kruskall Wallis test and if significant Mann-Whitney U-test as post hoc testing is applied. The significance level was P < 0.05.

RESULTS

All methods with the exception of phosphoric acid could decrease the initial amount of biofilm significantly. Among all air powder abrasive treatments, the HA + TCP group showed the best results with 99% biofilm removal, followed by HA and EMS powders. The cleaning method caused minimal changes to the surface structure. With the exception of the control group, all air powder applications caused sharp edges around the grooves in the implant surface to be rounded. TiO2 powder caused less change than HA and HA + TCP. Phosphoric acid did not cause a visible surface change on the SEM photos. Powder particles remnants were observed on and impacted in the titanium surface. In the HA and HA + TCP group, a Ca content was observed varying between 2% and 5%. In the control group, saliva and biofilm-related elements were observed.

CONCLUSIONS

Using the air powder abrasive method with calcium phosphate powders on contaminated titanium discs, an efficient implant cleaning and surface modification can be achieved. This method should be further improved as it has possible potential to be used as an implant surface treatment method for implants involved with peri-implantitis.

The effect of various topical peri-implantitis antiseptics on Staphylococcus epidermidis, Candida albicans, and Streptococcus sanguinis

OBJECTIVE

Although peri-implantitis has presented an ever increasing problem in modern dentistry, satisfying therapeutic strategies or scientifically based treatment recommendations are still not available. The main object of the present study was to evaluate the antibacterial efficacy of six different topical antiseptics on three test microorganisms attached to titanium implant specimens.

MATERIAL AND METHODS

For biofilm formation, plane titan specimens were incubated either in Candida albicans, Streptococcus sanguinis, or Staphylococcus epidermidis for 2h. The specimens were then treated with different topical antiseptics for 60s (sodium hypochlorite 1.0%, hydrogen peroxide 3.0%, chlorhexidine gluconate 0.2%, citric acid 40.0%, Plax, or Listerine) and with sterile saline as control. Remaining vital fungi were quantified by means of a bioluminometric assay and the bacterial load and the viability of adhering S. epidermidis and S. sanguinis by live or dead cell labelling in combination with fluorescence microscopy.

RESULTS

Sodium hypochlorite was effective against all three species, whereas hydrogen peroxide was solely effective against C. albicans. CHX and Listerine showed antimicrobial activity against S. sanguinis and C. albicans and citric acid and Plax against both tested bacteria.

CONCLUSIONS

None of the tested antimicrobial agents, except for sodium hypochlorite, showed a significant in vitro effect on all three test microbes. Considering the possible toxicity of sodium hypochlorite, none of the tested - and so far widely used - antiseptics showed any broad-spectrum antimicrobial effect and could therefore not be recommended for the topical disinfection and detoxification of infected implant surfaces.

Effect of erbium-doped: yttrium, aluminium and garnet laser irradiation on the surface microstructure and roughness of sand-blasted, large grit, acid-etched implants

PURPOSE

The present study was performed to evaluate the effect of erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser irradiation on sand-blasted, large grit, acid-etched (SLA) implant surface microstructure according to varying energy levels and application times of the laser.

METHODS

The implant surface was irradiated by the Er:YAG laser under combined conditions of 100, 140, or 180 mJ/pulse and an application time of 1 minute, 1.5 minutes, or 2 minutes. Scanning electron microscopy (SEM) was used to examine the surface roughness of the specimens.

RESULTS

All experimental conditions of Er:YAG laser irradiation, except the power setting of 100 mJ/pulse for 1 minute and 1.5 minutes, led to an alteration in the implant surface. SEM evaluation showed a decrease in the surface roughness of the implants. However, the difference was not statistically significant. Alterations of implant surfaces included meltdown and flattening. More extensive alterations were present with increasing laser energy and application time.

CONCLUSIONS

To ensure no damage to their surfaces, it is recommended that SLA implants be irradiated with an Er:YAG laser below 100 mJ/pulse and 1.5 minutes for detoxifying the implant surfaces.

Titanium surface alterations following the use of different mechanical instruments: a systematic review

OBJECTIVE

To systematically collect and evaluate existing evidence on the effects of different mechanical instruments on the surface characteristics of smooth and rough titanium surfaces.

MATERIALS AND METHODS

PubMed-MEDLINE, Cochrane-CENTRAL and EMBASE databases were searched up to December 2010 to identify appropriate studies. The eligible studies were controlled studies investigating titanium surface alterations following treatment with different mechanical instruments.

RESULTS

In total, 3275 unique papers were identified. A screening of the titles and abstracts resulted in 34 publications that met all of the eligibility criteria. Surface roughness was evaluated using scanning electron microscopy in most studies and using a profilometer in only 10 studies. The rough surfaces evaluated were titanium plasma sprayed and sandblasted and acid-etched surfaces only. Non-metal instruments were found to cause minimal or no damage to both smooth and rough titanium surfaces. Metal instruments were found to cause major damage to smooth surfaces. Burs seemed to be the instruments of choice, if smoothening of a rough surface was required.

CONCLUSION

Non-metal instruments and rubber cups seem to be the instruments of choice for the treatment of smooth surfaces. Similarly, for rough implant surfaces, non-metal instruments and air abrasives are the instruments of choice, if surface integrity needs to be maintained. Metal instruments and burs are recommended only in cases requiring the smoothening of the surface roughness. The clinical impact of these findings requires clarification.

The effect of Er:YAG laser irradiation on the surface microstructure and roughness of hydroxyapatite-coated implant

Purpose

The present study was performed to evaluate the effect of erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation on the change of hydroxyapatite (HA)-coated implant surface microstructure according to the laser energy and the application time.

Methods

The implant surface was irradiated by Er:YAG laser under combination condition using the laser energy of 100 mJ/pulse, 140 mJ/pulse and 180 mJ/pulse and application time of 1 minute, 1.5 minutes and 2 minutes. The specimens were examined by surface roughness evaluation and scanning electron microscopic observation.

Results

In scanning electron microscope, HA-coated implant surface was not altered by Er:YAG laser irradiation under experimental condition on 100 mJ/pulse, 1 minute. Local areas with surface melting and cracks were founded on 100 mJ/pulse, 1.5 minutes and 2 minutes. One hundred forty mJ/pulse and 180 mJ/pulse group had surface melting and peeling area of HA particles, which condition was more severe depending on the increase of application time. Under all experimental condition, the difference of surface roughness value on implant surface was not statistically significant.

Conclusions

Er:YAG laser on HA-coated implant surface is recommended to be irradiated below 100 mJ/pulse, 1 minute for detoxification of implant surface without surface alteration.

The peri-implantitis: implant surfaces, microstructure, and physicochemical aspects

There are two ways of looking at secondary failures of osseointegration; one is to reflect on possible causes for the failure, the other focuses on the pathology per se. In the first case, background factors such as mechanical trauma (adverse loading) or inflammations/infections are being discussed as the cause of failure. Then peri-implantitis is a term reserved for implant disturbance due to inflammation/infections only. However, irrespective of the original reason for the failure being adverse loading or inflammation/infection, the end result with bone resorption and inflammation may be very similar. Hence, in the present article, an alternative outlook has been chosen. Trigerring factors for peri-implantitis are generally gathered under four categories: lesions of peri-implant attachment, presence of aggressive bacteria, excessive mechanical stress, and corrosion. If only one of these factors would start a chain reaction leading to lesions, then the other factors may combine to worsen the condition. With other words, peri-implantitis is a general term dependent on a synergy of several factors, irrespective of the precise reason for first triggering off symptoms.

Effect of Er:YAG, CO(2) and diode laser irradiation on surface properties of zirconia endosseous dental implants

BACKGROUND AND OBJECTIVES

Zirconia implants (ZI) are becoming more popular in implant dentistry, as a result of their favorable esthetic outcome. However, little is known about the impact laser application has on this material in the course of peri-implantitis treatment. The objective of this investigation was to analyze the influence of Er:YAG, CO(2) and diode laser irradiation on polished ZI.

MATERIAL AND METHODS

Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic disks were irradiated at different power settings with either an Er:YAG, CO(2) or diode laser. The surface of the disks was analyzed by scanning electron microscopy (SEM) and confocal 3D white light microscopy (CWLM). In addition energy-dispersive X-ray (EDX) analysis was performed on all disks. Six specimens were used for each parameter set of each laser.

RESULTS

SEM analysis demonstrated that, regardless of the power settings, neither the diode laser nor the Er:YAG laser caused any visible surface alterations to ZI. The results of the CWLM were in agreement with the SEM pictures. However, Er:YAG irradiation did penetrate through the disks. At various power settings, the CO(2) treatment was characterized by material cracking and melting. The increased roughness values (from CWLM) of the ZI underlined the SEM observations.

CONCLUSION

In contrast to diode and Er:YAG laser irradiation, the CO(2) laser revealed distinct surface alterations to zirconia at various laser parameters. However, the Er:YAG laser cannot be recommended for the treatment of ailing implants, as the laser beam penetrates the material. In this respect, currently, diode lasers seem to be the only laser systems offering surface preservation and safety in the treatment of peri-implantits with ZI.

Implant Surface Analysis and Microbiologic Evaluation of Failed Implants Retrieved From Smokers

The aim of this study was to evaluate the microbiota and surface of failed titanium dental implants from 4 manufacturers. Twelve mobile dental implants were retrieved from 10 smokers after 3 to 10 years of functional loading. Before implant removal, microbial samples were taken and evaluated using polymerase chain reaction. After implant removal, analyses of the failed implant surfaces were performed using scanning electron microscopy and energy-dispersive spectrometer x-ray. Periodontal pathogens such as Aggregactibacter actinomycetemcomitans, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola were detected in all implants in different proportions. Surface analysis showed varying degrees of surface roughness between the samples and the presence of proteinaceous material, appearing mainly as dark stains. Foreign carbon, oxygen, sodium, calcium, aluminum, and silicon elements were also found. Although no material-related causes of implant failure were detected, several periodontal pathogens were identified independently of the surface topography or manufacturer.

Neodymium:yttrium aluminum garnet laser irradiation with low pulse energy: a potential tool for the treatment of peri-implant disease

Bacterial contamination may seriously compromise successful implant osteointegration in the clinical practice of dental implantology. Several methods for eliminating bacteria from the infected implants have been proposed, but none of them have been shown to be an effective tool in the treatment of peri-implantitis. In the present study, we investigated the efficacy of pulsed neodymium:yttrium aluminum garnet laser irradiation (Nd:YAG) in achieving bacterial ablation while preserving the surface properties of titanium implants. For this purpose, suspensions of Escherichia coli or Actinobacillus (Haemophilus) actinomycetemcomitans were irradiated with different laser parameters, both streaked on titanium implants, and in broth medium. It was found, by light and atomic force microscopy, that Nd:YAG laser, when used with proper working parameters, was able to bring about a consistent microbial ablation of both aerobic and anaerobic species, without damaging the titanium surface.

Analysis of Failed Commercially Pure Titanium Dental Implants: A Scanning Electron Microscopy and Energy-Dispersive Spectrometer X-Ray Study

BACKGROUND

The failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure.

METHODS

Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant.

RESULTS

SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium.

CONCLUSION

These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.

Carbon Dioxide Laser and Hydrogen Peroxide Conditioning in the Treatment of Periimplantitis: An Experimental Study in the Dog

BACKGROUND

Various methods have been applied for the treatment of periimplantitis lesions. It has been reported that the procedures used have been effective in eliminating the inflammatory lesion but that re-osseointegration to the once-contaminated implant surface has been difficult or impossible to achieve.

PURPOSE

The aim of this study was to examine the use of carbon dioxide (CO2) laser in combination with hydrogen peroxide in the treatment of experimentally induced periimplantitis lesions.

MATERIALS AND METHODS

Three dental implants (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland) were placed in each side of the edentulous mandible of four beagle dogs. Implants with a turned surface and implants with a sand-blasted large-grit acid-etched (SLA) surface (SLA, Straumann AG, Waldenburg, Switzerland) were used. Experimental periimplantitis was induced during 3 months. Five weeks later each animal received tablets of amoxicillin and metronidazole for a period of 17 days. Three days after the start of the antibiotic treatment, full-thickness flaps were elevated, and the granulation tissue in the bone craters was removed. In the two anterior implant sites in both sides of the mandible, a combination of CO2 laser therapy and application of a water solution of hydrogen peroxide was used. The implant in the posterior site of each quadrant was cleaned with cotton pellets soaked in saline. Biopsy specimens were obtained 6 months later.

RESULTS

The amount of re-osseointegration was 21% and 82% at laser-treated turned-surface implants and SLA implants, respectively, and 22% and 84% at saline-treated turned-surface implants and SLA implants, respectively.

CONCLUSIONS

The present study demonstrated the following: (1) a combination of systemic antibiotics and local curettage and debridement resulted in the resolution of experimentally induced periimplantitis lesions; (2) at implants with a turned surface, a small amount of re-osseointegration was observed at the base of the bone defects whereas a considerable amount of re-osseointegration occurred at implants with an SLA surface; and (3) the use of CO2 laser and hydrogen peroxide during surgical therapy had no apparent effect on bone formation and re-osseointegration.

Prevention. Part 5: Preventive strategies for patients requiring osseointegrated oral implant treatment

Prevention for patients requiring rehabilitation with oral implants is about preventing implant failure and biomechanical complications. This paper describes preventative strategies for the planning stage for implant treatment and the later maintenance period and indicates the level of scientific evidence supporting these strategies.

Implant surface preparation in the surgical treatment of experimental peri-implantitis with autogenous bone graft and ePTFE membrane in cynomolgus monkeys

The aim of the present investigation was to assess the effect of four implant surface preparation methods used in the surgical treatment of experimental peri-implantitis with autogenous bone graft and expanded polytetrafluoroethylene (ePTFE) membrane. The methods were air-powder abrasive unit+citric acid, air-powder abrasive unit, gauze soaked in saline+citric acid, and gauze soaked alternately in chlorhexidine and saline. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was placed in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month period with plaque control, experimental peri-implantitis was induced. A bone loss of 4-6 mm was established after 9-17 months and plaque control was re-implemented. The peri-implantitis defects were surgically exposed, granulation tissue was removed, and each implant surface was prepared by one of the above-mentioned procedures. The defects were then filled with autogenous bone graft particles and covered by an ePTFE membrane. The animals were sacrificed after 6 months. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology did not reveal significant differences between the methods. Almost total bone regeneration and considerable re-osseointegration were obtained irrespective of the method applied. A mean bone-to-implant contact of 39-46% was observed within the defects. Therefore, the present study of implants with a TPS surface in cynomolgus monkeys indicates that the simplest method involving gauze soaked alternately in chlorhexidine and saline should be the preferred implant surface preparation method in the surgical treatment of peri-implantitis involving autogenous bone graft and ePTFE membrane.

A possible "rescue" procedure for dental implants with a textured surface geometry: a case report

Dental implants with textured surfaces are a valuable adjunct in restoring edentulous sites of poor bone quality and quantity, but on occasion may become denuded of bone and require "rescue." We report here the successful management of an intrabony crater affecting a single porous-surfaced dental implant using a combination of citric acid decontamination and grafting with freeze-dried, demineralized allograft covered with a barrier of calcium sulfate.

Confocal laser scanning microscopy and scanning electron microscopy of tissue Ti-implant interfaces

Microscopic inspection of heterogenous three-dimensional (3D) objects such as oral implants, or implants in general, is conventionally performed either on ground sections of methyl-metacrylate-embedded material, at the cellular level by histologic analysis of the peri-implant tissue by light microscopy (LM), or at the supramolecular level by transmission electron microscopy (TEM). Alternatively, the architecture of the tissue/implant interface is visualized by scanning electron microscopy (SEM). The two approaches exclude each other because of the sample preparation.We elaborate conditions for the non-invasive analysis of tissue/implant interfaces by confocal laser scanning microscopy (CLSM) in buffer, hoping to obtain a 3D view of fluorescently labeled tissue constituents at the tissue implant interface and, through subsequent SEM, of the metal surface. The use of water-immersion objectives, originally developed for high LM under physiological conditions is essential. In an exploratory approach, the tissue/Ti-interfaces of two retrieved dental implants were analyzed. One was a step-cylinder used for orthodontic anchoring and the other was an endosseous step-screw implant retrieved after infection-related loosening prior to load. The adhering tissue fragments were fluorescently triple-labeled for actin, fibronectin, and sm-alpha-actin. Optical sections for fluorescent images and for the laser reflection map were registered concomitantly. This approach allowed the labeled structures to be located on the metal surface. Subsequently, the same implants were prepared for SEM of the tissue/implant interface, and upon removal of the adhering structures, of the underlying metal surface. Thus, specific proteins can be identified and their spatial architecture as well as that of the underlying metal surface can be visualized for one and the same implant. The immediate visualization after fluorescence labeling in buffer by means of water immersion objective lenses proved most critical.

Re-Establishment of the Atomic Composition and the Oxide Structure of Contaminated Titanium Surfaces by Means of Carbon Dioxide Laser and Hydrogen Peroxide: An In Vitro Study

BACKGROUND

In clinical situations with peri-implant bone resorption, re-integration of the exposed implant surface is sometimes preferable, which requires a clean surface. Previous investigations have shown that cleaning of contaminated titanium surfaces using chemical and abrasive methods is difficult.

PURPOSE

The aim of this investigation was to evaluate the efficacy of different combinations of chemical and physical methods (citric acid, hydrogen peroxide, and carbon dioxide [CO2] laser irradiation) for removal of contaminants and subsequent reconstruction of the surface oxide of intraorally contaminated titanium foils.

MATERIALS AND METHODS

Commercially pure titanium foils (99.6%, 5 x 5 mm in size) were contaminated by placement on dentures in volunteering patients, simulating a peri-implantitis situation. The contaminated foils and clean control foils were treated by seven and six combinations of citric acid, hydrogen peroxide, and CO2 laser irradiation, respectively. The effect of the cleaning procedures was evaluated by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM).

RESULTS

The initial elemental composition of the contaminated foils was 70% carbon (C), 20% oxygen (O), 10% nitrogen (N), and only traces of titanium (Ti) (< 1%). One treatment proved to be more effective than the others: irradiations by 5-second cycles of superpulsed CO2 laser at a power of 7 W, 10-millisecond pulse width, and with an 80-Hz frequency on a wet surface, followed by repeated application of supersaturated citric acid for 30 seconds, each time followed by rinsing with ultrapure water until all tissue remnants had been removed. Finally, hydrogen peroxide of 10-mM concentration was added to the implant surface and evaporated by CO2 laser at the same settings. This treatment protocol resulted in 10% Ti, 45% O, 41% C, and 2 to 3% N, a composition comparable to that of unused foils: 9% Ti, 40% O, 48% C, and traces of N and chlorine (CI). X-ray photoelectron spectroscopy profiles showed that the thickness of the surface oxide was restored and even augmented with this protocol for treatment of contaminated titanium.

CONCLUSION

A combination of citric acid, hydrogen peroxide, and CO2 laser irradiation seems to be effective for cleaning and reestablishment of the atomic composition and oxide structure of contaminated titanium surfaces.