The Effects of Er:YAG Laser Treatment on Titanium Surface Profile and Osteoblastic Cell Activity: An In Vitro Study

Protein absorption on titanium surfaces treated with a high-power laser: A systematic review

STATEMENT OF PROBLEM

The surface of titanium dental implants treated with a high-power laser has been reported to favor osseointegration, mainly by altering protein uptake. Despite the large number of articles that address the topic, the heterogeneity of methodologies and results makes an understanding of the treatment's benefits difficult, and a systematic review is needed.

PURPOSE

The purpose of this systematic review was to further the knowledge on protein uptake on titanium surfaces that have undergone treatment with a high-power laser.

MATERIAL AND METHODS

This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and was registered with the Open Science Framework (OSF) (osf.io/gcbna). Searches were performed in PubMed, Scopus, Web of Science, Embase, and Google Scholar databases. The articles were selected in 2 steps by 2 independent reviewers according to the previously selected eligibility criteria. The risk of bias was analyzed by using the Joanna Briggs Institute (JBI)-adapted quasi-experimental study evaluation tool.

RESULTS

The studies addressed have shown that applying a high-power laser to the implant surface, depending on its settings, generates topographical changes that can optimize the protein absorption process and thus accelerate the other biological processes.

CONCLUSIONS

The studies identified in this systematic review showed that surface treatment with a high-power laser represents a promising technique with a positive influence on protein uptake and osseointegration.

Influence of Clinical Decontamination Techniques on the Surface Characteristics of SLA Titanium Implant

The study aims: 1. To perform diode laser, titanium (Ti) brush, and Ti curette treatment on sandblasted and acid-etched (SLA) Ti surfaces, with/without H2O2 and CHX, 2. To investigate the influence of decontamination techniques on implant surface topography and hydrophilicity. Diode laser, Ti brush, and Ti curette treatments were performed on the Grade 4 Ti discs, with/without treatment with 3% H2O2 solution or 0.2% CHX. Surface characteristics were investigated via SEM, optical profilometry, and water contact angle meter. SEM findings revealed flat and scratched areas when treated with Ti curette and Ti brush. For diode laser, SEM showed melting in specific areas. Ra and Rt values were lower in all test groups than in the control group (p < 0.05). The adjunctive chemical treatment showed negligible effects in SEM images and surface roughness measurements compared to laser and mechanical treatment-only groups. H2O2 treatment resulted in enhanced hydrophilicity in either treatment modalities with a significant difference compared to the negative control group (p < 0.05). In all test groups, the hydrophilicity was enhanced compared to the negative control group (p < 0.05). Diode laser treatment had the least disruptive effect on the Ti surface characteristics. The use of other mechanical methods caused significant alterations in the surface roughness.

A comparison of human dental pulp stem cell activity cultured on sandblasted titanium discs decontaminated with Er:YAG laser and air-powder abrasion: an in vitro study

Decontamination of implant surfaces is important to the treatment of peri-implantitis. Er:YAG laser and air-powder abrasion system are regarded as the most effective means of decontamination of implant surfaces. The aim of this in vitro study was to compare the activity of human dental pulp stem cells (hDPSCs) cultured on decontaminated sandblasted titanium discs using Er:YAG laser irradiation and air-powder abrasion. Forty-five titanium discs were contaminated with Escherichia coli (E. coli) bacteria and fifteen titanium discs served as sterile control groups. Thirty contaminated titanium discs were decontaminated with Er:YAG laser or air-powder abrasion system and fifteen contaminated discs were used as contaminated control group. Afterwards, hDPSCs were seeded on all sixty experimental titanium discs. The effects of two decontamination tools on hDPSCs viability were evaluated by MTT assay. Alkaline phosphatase (ALP) activity assay, quantitative real-time PCR analysis and alizarin red staining method were performed to assess hDPSCs osteogenic differentiation. Scanning microscope electron (SEM) was also used to evaluate the effects of two different decontaminated methods on cellular morphology. Our study showed that decontamination using Er:YAG laser caused maximum cell viability. However, the ALP activity was not different in laser and air-abrasion groups. The significant expression of an osteoblastic marker and stronger Alizarin red staining were observed in laser irradiation groups. In addition, SEM observation indicated that grown cells were more stretched and more filopodia in Er:YAG-treated discs. In the present study, Er:YAG laser and air-powder abrasion improved the activity of the cells cultured on the decontaminated titanium discs. However, in comparison with air-powder abrasion, Er:YAG laser was more effective.

Efficacy of Er:YAG laser irradiation for decontamination and its effect on biocompatibility of different titanium surfaces

Background

Erbium yttrium–aluminum–garnet (Er:YAG) laser have been shown to be suitable for decontamination of titanium surfaces at a wide range of energy settings, however, high intensity of laser irradiation destroy titanium surface and low intensity cannot remove enough microbial biofilm. The aim of this study was to investigate the optimal energy setting of Er:YAG laser for decontamination of sandblasted/acid-etched (SLA) and hydroxyapatite (HA) titanium surfaces.

Material and methods

After supragingival biofilm construction in vivo, SLA and HA titanium discs were divided into three groups: blank control (BC, clean discs), experimental control (EC, contaminated discs) and experimental groups (EP, contaminated discs irradiated by Er:YAG laser at 40, 70, and 100 mJ/pulse). Scanning electron microscopy (SEM), live/dead bacterial fluorescent detection, and colony counting assay were used to detect the efficacy of laser decontamination. To investigate the effect of laser decontamination on titanium surface biocompatibility, MC3T3-E1 cell adhesion and proliferation activity were examined by SEM and CCK-8 assay.

Results

Er:YAG laser irradiation at 100 mJ/pulse removed 84.1% of bacteria from SLA titanium surface; laser irradiation at 70 and 100 mJ/pulse removed 76.4% and 77.85% of bacteria from HA titanium surface respectively. Laser irradiation improved MC3T3-E1 cell adhesion on both titanium surfaces. For SLA titanium discs, 100 mJ/pulse group displayed excellent cellular proliferation activity higher than that in BC group (P < 0.01). For HA titanium discs, 70 mJ/pulse group showed the highest activity comparable to BC group (P > 0.05).

Conclusions

With regards to efficient microbial biofilm decontamination and biocompatibility maintenance, Er:YAG laser at 100 mJ/pulse and 70 mJ/pulse are considered as the optimal energy settings for SLA titanium and HA titanium surface respectively. This study provides theoretical basis for the clinical application of Er:YAG laser in the treatment of peri-implantitis.

Effects of Er:YAG laser irradiation of different titanium surfaces on osteoblast response

The aim of this in vitro study was to evaluate the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation on titanium surface topography and the proliferation and differentiation of osteoblasts using standard clinical treatment settings. Er:YAG laser irradiation at two levels ((1): 160 mJ, pulse at 20 Hz; (2): 80 mJ, pulse at 20 Hz) was applied to moderately rough and smooth titanium disks before MG-63 osteoblast-like cells were cultured on these surfaces. Titanium surface and cell morphology were observed by scanning electron microscopy. Cell proliferation/viability was measured by CCK-8 test. Gene expression of alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), and collagen type 1 was measured by qPCR, and OPG and OC protein production was determined by enzyme-linked immunosorbent assay. Treatment with Er:YAG laser at 160 mJ/20 Hz markedly caused heat-induced fusion of titanium and cell condensation on moderately rough surfaces, but not in smooth surfaces. MG-63 proliferation/viability decreased after 5 days in moderately rough surfaces. The expression of ALP, OC, OPG, and collagen type 1 was unaffected by laser treatment at 160 mJ/20. Laser irradiation at 80 mJ/20 Hz enhanced RANKL gene expression after 5 days in moderately rough surfaces. Study results suggest that Er:YAG laser irradiation at clinically relevant setting has no essential effect on osteogenic gene and protein expression of osteoblasts. However, surface structure, cell attachment, and proliferation are influenced by both treatment protocols, which implies that caution should be taken in the clinical treatment of peri-implant diseases when Er:YAG laser is used.

Cleaning Efficacy of Poly-ether-ether-ketone Tips in Eliminating Cement Remnants Around Implants With Different Abutment Heights

The excess cement not removed after the cementation of fixed implant-supported restorations may cause loss of peri-implant attachment or adjacent bone. The aims of this study were to evaluate the amount of residual cement at different abutment-crown connection levels and to test the cleaning efficacy of poly-ether-ether-ketone (PEEK) ultrasonic tips after cementation. One implant was placed in an anterior central tooth position 5 mm below the gingival margin in an acrylic model, and 32 stone models were obtained with implant analogs. Abutment heights of 1-2 and 2.5-4 mm were used on the vestibular and lingual sides, respectively. Crowns were cemented and cleaned, and half of the samples were cleaned again using PEEK tips. The abutment-crown suprastructure was then disconnected, and cleaning efficacy was evaluated. Varying amounts of excess cement were found on all specimens except for the PEEK group with abutment-crown connections 1 mm below the gingival margin. An increase of undetected cement remnants was observed when the restoration margins were located deeper subgingivally. Various amounts of excess cement associated with margin location were detected on the abutment-restoration complex despite meticulous cleaning efforts. Ultrasonic PEEK tips were effective at cleaning the cement remnants around implants to a certain depth.

The Effects of Erbium-Doped Yttrium Aluminum Garnet Laser (Er: YAG) Irradiation on Sandblasted and Acid-Etched (SLA) Titanium, an In Vitro Study

The treatment of peri-implantitis implies the decontamination of the surface of the fixture. This study aims to analyze the effect of the erbium-doped yttrium aluminum garnet laser (Er: YAG) on sandblasted and acid-etched (SLA) titanium. 30 titanium SLA disks were divided into three groups. In Group 1, the disks were left intact; on the contrary, both Groups 2 and 3 were irradiated with the Er: YAG laser at different settings, with a pulse duration of 300 μs and a period of 30 s. Group 2 was irradiated at 1 W and 100 mJ/pulse and Group 3 at 4 W and 400 mJ/pulse. The superficial changes at chemical, nano, and microscopical levels were detected through the use of Fourier-transform infrared spectroscopy, atomic force microscopy, and scanning electron microscope. The Kruskal–Wallis test, followed by the Dunn–Bonferroni Post Hoc analysis, detected the presence of statistically significant differences among the groups. The level of significance was p ≤ 0.05. Results showed that Er: YAG irradiation promoted a significant (p < 0.05) increase of oxides and a decrease of microscopical roughness and porosity on SLA disks. However, the protocol tested on group 3 seemed to be too aggressive for the titanium surface, as shown by the presence of micro-cracks and signs of coagulation, melting, and microfractures. In conclusion, Group 2 showed significantly minor surface alterations with respect to Group 3, and the increase of superficial oxide level, the decrease of porosity, and micro-roughness represent a positive alteration that could protect the materials against bacterial adhesion.

Effects of Lasers and Their Delivery Characteristics on Machined and Micro-Roughened Titanium Dental Implant Surfaces

The aim of the study was to investigate the effects of neodymium: yttrium aluminium garnet (Nd:YAG) (1064 nm) and erbium: yttrium aluminium garnet (Er:YAG) (2940 nm) laser energy on titanium when delivered with conventional optics (focusing handpieces or plain ended optical fibres) or with a conical tip. Machined and micro-roughened implant discs were subjected to laser irradiation under a variety of energy settings either dry (without water) or wet (with water). Samples were scanned using a 3D non-contact laser profilometer and analysed for surface roughness, volume of peaks and the maximum diameter of the ablated area. Conical tip designs when used with both lasers showed no surface effect at any power setting on both machined and micro-roughened implant surfaces, regardless of the irrigation condition. When used with conventional delivery systems, laser effects on titanium were dose related, and were more profound with the Nd:YAG than with the Er:YAG laser. High laser pulse energies caused surface fusion which reduced the roughness of micro-roughened titanium surfaces. Likewise, repeated pulses and higher power densities also caused greater surface modifications. The presence of water reduced the influence of laser irradiation on titanium. It may be concluded that conical fibres can reduce unwanted surface modification, and this may be relevant to clinical protocols for debridement or disinfection of titanium dental implants.

Er,Cr:YSGG laser surface treatment of gamma titanium aluminide: Scanning electron microscopy-energy-dispersive X-ray spectrometer analysis, wettability and Eikenella corrodens and Aggregatibacter actinomycetemcomitans bacteria count-in vitro study

Dental implants play an important role in oral health. Titanium dental implants must endure the complex microflora environment of the oral cavity. Moreover, bacterial infections have been considered as one of the most important factors of implant failure. The issue of dental improvement through modification of chemical composition and surface treatment has received considerable critical attention. γ-TiAl as a novo biocompatible material revealed a slower corrosion rate in biological media rather Ti-6Al-4V. The objective of this study is to investigate the effect of Er,Cr:YSGG laser on γ-TiAl in comparison with sandblasted and acid-etched samples as the control groups and machined samples.Wettability, surface roughness, surface topography, scanning electron microscopy-energy dispersive X-ray spectrometer analysis of surface and subsurface of samples were investigated and bacteria counts of two periodontal bacterial strains (Aggregatibacter actinomycetemcomitans and Eikenella corrodens) were evaluated on the Er,Cr:YSGG laser surface-treated sandblasted and acid-etched and machined samples.The results of this investigation show that Er,Cr:YSGG laser surface treatment affects surface roughness, surface topography, wettability, chemical composition of the surface and bacteria count. Scanning electron microscopy-energy dispersive X-ray spectrometer analysis of the sample revealed the increment of titanium and oxygen content and reduction of aluminum content in the surface and subsurface layer. A. actinomycetemcomitans and E. corrodens count were found from the lowest level to highest in the sandblasted and acid-etched samples, laser samples and machined samples, respectively.Using controlled parameters of Er,Cr:YSGG laser ensured no significant adverse alteration. The findings to emerge from this study revealed the significant correlation between microbial count and wettability. Furthermore, the contact angle strongly correlated with surface roughness.

Picosecond laser texturing on titanium alloy for biomedical implants in cell proliferation and vascularization

Introducing specific textures to titanium alloy implant surface is helpful to modify the surface properties of materials. In this article, biomedical TC4 (Ti-6Al-4V) alloy was textured by a 10-ps infrared laser. Laser parameters that directly affected the detailed dimension of textures and its characteristics were optimized within laser power, defocusing amount, and scanning parameters via response surface methodology. These textures consisted of groove array about 30-90 μm in depth and 100 μm in width were prepared and their surface property (including surface morphology, element composition, wetting behavior, and biocompatibility) was analyzed. Surface characteristic analysis indicated that picosecond laser texturing improved surface properties and biocompatibility mainly by altering the microstructure and morphology of materials. In addition, laser textured groove array promoted contact area and hydrophobicity of material surface. Cell culture experiments and animal studies showed that titanium alloy implants with 30- and 60-μm-deep groove arrays on the surface-enhanced cell proliferation and adhesion. Meanwhile, compared to the polished samples, these groove arrays promoted the growth of new blood vessels and enhanced the combination of blood vessel and implants in vivo. That is, the deeper groove array was, and the better vascularizing effect the blood vessel exhibited.

Efficacy of antimicrobial photodynamic therapy for elimination of Aggregatibacter actinomycetemcomitans biofilm on Laser-Lok titanium discs

BACKGROUND

Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs.

MATERIALS AND METHODS

Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 μg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test.

RESULTS

Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05).

CONCLUSION

Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs.

Decontamination of Dental Implant Surfaces by the Er:YAG Laser Beam: A Comparative in Vitro Study of Various Protocols

Oral rehabilitation with dental implants has revolutionized the field of dentistry and has been proven to be an effective procedure. However, the incidence of peri-implantitis has become an emerging concern. The efficacy of the decontamination of the implant surface, by means of lasers, is still controversial. Previous studies have revealed a reduction in osteoblast adhesion to carbon-contaminated implant surfaces. This in-vitro study aimed to evaluate the decontamination of failed implants by assessing the carbon proportion, after irradiation by low-energy erbium yttrium-aluminum-garnet laser (Er:YAG) (Fotona; 2940 nm, Ljubljana, Slovenia) for a single and for multiple passages, until getting a surface, free of organic matters; to find the appropriate procedure for dental-implant surface-decontamination. Ninety implants were used. Thirty sterile implants were kept as a negative control. Thirty failed implants were irradiated by the Er:YAG laser, for a single passage, and the other thirty, for multiple passages. The parameters used in our experiments were an irradiation energy of 50 mJ, frequency of 30 Hz, and an energy density of 3.76 J/cm². A sapphire tip, with a length of 8 mm, was used with concomitant water spray irrigation, under air 6 and water spray 4. Super short pulse mode (SSP) was of 50 μs; irradiation speed being 2 mm/s. We used energy-dispersive X-ray spectroscopy (EDX) to evaluate the carbon proportion on the surfaces of the sterile implants, the contaminated, and the lased implants, with one (LX1) and with three passages (LX3). Statistical analysis was performed by ANOVA. Results showed mean difference between the three groups (contaminated, LX1, and LX3) with p < 0.0001, as between LX1 and Group A (p < 0.0001), while the difference between LX3 and the control group was not statistically significant. The decontamination of the implant surfaces with a low-energy Er:YAG laser with three passages, appeared to be an encouraging approach.

Potential Causes of Titanium Particle and Ion Release in Implant Dentistry: A Systematic Review

Implant surface characteristics, as well as physical and mechanical properties, are responsible for the positive interaction between the dental implant, the bone and the surrounding soft tissues. Unfortunately, the dental implant surface does not remain unaltered and changes over time during the life of the implant. If changes occur at the implant surface, mucositis and peri-implantitis processes could be initiated; implant osseointegration might be disrupted and bone resorption phenomena (osteolysis) may lead to implant loss. This systematic review compiled the information related to the potential sources of titanium particle and ions in implant dentistry. Research questions were structured in the Population, Intervention, Comparison, Outcome (PICO) framework. PICO questionnaires were developed and an exhaustive search was performed for all the relevant studies published between 1980 and 2018 involving titanium particles and ions related to implant dentistry procedures. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the selection and inclusion of the manuscripts in this review. Titanium particle and ions are released during the implant bed preparation, during the implant insertion and during the implant decontamination. In addition, the implant surfaces and restorations are exposed to the saliva, bacteria and chemicals that can potentially dissolve the titanium oxide layer and, therefore, corrosion cycles can be initiated. Mechanical factors, the micro-gap and fluorides can also influence the proportion of metal particles and ions released from implants and restorations.

Periodontal and peri-implant wound healing following laser therapy

Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal nonsurgical and surgical treatment, osseous surgery and peri-implant treatment, focusing on postoperative wound healing of periodontal and peri-implant tissues, based on scientific evidence from currently available basic and clinical studies, as well as on case reports.

Osteoblast differentiation is enhanced by a nano-to-micro hybrid titanium surface created by Yb:YAG laser irradiation

OBJECTIVES

The aim of this study was to analyze the capacity of a new modified laser surface to stimulate calvarial osteoblasts isolated from neonatal mouse bones to differentiate and form mineralized nodules.

METHODS

Titanium discs were subjectezd or not to laser irradiation according to specific parameters and characterized. Osteoblasts isolated from neonatal mouse calvaria were cultured over the discs, and the capacity of these cells to proliferate (MTT assay), form mineralized nodules (Alizarin red assay), and enhance alkaline phosphatase activity (ALPase activity) was analyzed. Real-time PCR was used for quantification of gene expression.

RESULTS

Laser-irradiated titanium discs (L) presented a rough nano-to-micrometric oxidized surface contrasting with the smooth pattern on polished discs (P). The Ra on the micrometric level increased from 0.32 ± 0.01 μm on P surfaces to 10.57 ± 0.39 μm on L surfaces. When compared with P, L promoted changes in osteoblast morphology, increased mineralized nodule formation in osteoblasts cultured on the surfaces for 14 days, and enhanced ALPase activity at days 7 and 14. Transcription factors triggering osteoblast differentiation (Runx2 and Sp7) and genes encoding the bone extracellular matrix proteins collagen type-1 (Col1a1), osteopontin (Spp1), and osteocalcin (Bglap) were upregulated in cells on L surfaces compared with those on P surfaces at days 1-14.

CONCLUSION

Laser treatment of titanium surfaces created a rough surface that stimulated osteoblast differentiation.

CLINICAL RELEVANCE

Laser treatment of titanium generates a reproducible and efficient surface triggering osteoblast differentiation that can be of importance for osteointegration.

An in vitro evaluation of the responses of human osteoblast-like SaOs-2 cells on SLA titanium surfaces irradiated by different powers of CO2 lasers

Bacterial biofilms have been identified as the primary etiological factor for the development and progression of peri-implantitis. Lasers have been shown to remove bacterial plaque from titanium surfaces effectively and can restore its biocompatibility without damaging these surfaces. Therefore, the aim of this study was to evaluate the responses (i.e., the cell viability and morphology) of human osteoblast-like SaOs-2 cells to sandblasted, large grit, and acid-etched (SLA) titanium surfaces irradiated by CO2 lasers at two different power outputs. A total of 24 SLA disks were randomly radiated by CO2 lasers at either 6 W (group 1, 12 disks) or 8 W (group 2, 12 disks). Non-irradiated disks were used as a control group (four disks). The cell viability rates of the SaOs-2 cells in the control and study groups (6 and 8 W) were 0.33 ± 0.00, 0.24 ± 0.11, and 0.2372 ± 0.09, respectively (P < 0.6). Cells with cytoplasmic extensions and spreading morphology were most prominent in the control group (141.00 ± 29.00), while in the study groups (6 and 8 W), the number of cells with such morphology was 60.40 ± 26.00 and 35.20 ± 5.40, respectively (P < 0.005). Within the limits of this study, it may be concluded that the use of CO2 lasers with the aforementioned setting parameters could not be recommended for decontamination of SLA titanium surfaces.

Root Surface Bio-modification with Erbium Lasers- A Myth or a Reality??

The objective of this literature review was to critically review the evidence available in the literature regarding the expediency of erbium family of lasers for root bio modification as a part of periodontal therapy. The literature search was performed on the Pubmed using MeSH words such as "lasers/therapeutic use, scaling, dental calculus, tooth root/anatomy and histology, ultrasonic therapy". The studies were screened and were grouped as follows: those evaluating a) efficacy for calculus removal with the Erbium family of laser b) root surface changes following Er YAG and Er Cr YSGG application c) comparative studies of the Er YAG, Er Cr YSGG lasers versus conventional methods of root surface modification d) Bio compatibility of root surface following Erbium laser treatment e) Studies on the combined efficacy of laser root modification with conventional methods towards root surface bio-modification f) Studies on effectiveness of root surface bio-modification prior to root coverage procedures. In conclusion, the erbium family has a proven anti-bacterial action, predictable calculus removal, minimal root substance removal, and appears to favor cell attachment. The Erbium family of lasers appears to be a useful adjunct for the management of periodontal disease.

Effects of Er: YAG laser irradiation on wettability, surface roughness, and biocompatibility of SLA titanium surfaces: an in vitro study

The erbium: yttrium-aluminum-garnet (Er: YAG) laser has been introduced as an effective method in the decontamination of implant surfaces. Data concerning the effects of the Er: YAG laser on the biological and surface properties of titanium are conflicting. Cellular behavior is greatly affected by surface properties, including composition, roughness, wettability, and morphology of the titanium surface. The aim of this study was to investigate the influence of the Er: YAG laser on the biocompatibility, surface roughness, and wettability of sandblasted and acid-etched (SLA) titanium surfaces. Twenty-one SLA titanium disks were irradiated by the Er: YAG laser at a pulse energy of 100 mJ, with a pulse frequency of 10 Hz under water irrigation for 1 min. Cell viability, surface roughness, and wettability alterations were evaluated. Thirteen nonirradiated SLA disks were used as the control groups. Human osteoblast-like SaOs-2 cells were seeded onto the disks in culture media. Cell viability was evaluated using the methylthiazol tetrazolium assay. The surface roughness and wettability of the test and control groups were measured using profilometer and tensiometer devices, respectively. A significantly higher cell viability rate was observed in the test group (p = 0.032). The surface roughness was significantly reduced in the test group compared with the control group (p = 0.008). The surface wettability was significantly higher in the test group (p = 0.004). Within the limits of this study, the application of the Er: YAG laser with the previously described properties did not appear to have adverse effects on the biocompatibility of the SLA titanium surfaces. Application of this laser decreased the surface roughness and increased the wettability of the SLA titanium surfaces.