Temperature increase during CO(2) and Er:YAG irradiation on implant surfaces

Efficacy of laser in re-osseointegration of dental implants-a systematic review

Despite their high success rates, peri-implantitis can affect the stability and function of dental implants. Various treatment modalities have been investigated for the treatment of peri-implantitis to achieve re-osseointegration. An electronic literature search was performed supplemented by a manual search to identify studies published until January 2022. Articles that evaluated re-osseointegration in peri-implantitis sites in animal models following laser therapy or antimicrobial photodynamic therapy (aPDT) were included. Case reports, case series, systematic reviews, and letters to the editor were excluded. Risk of bias and GRADE assessment were followed to evaluate the quality of the evidence. Six studies out of 26 articles identified on electronic search were included in this review. The studies included animal studies conducted on canine models. Four out of six studies reported a higher degree of re-osseointegration following treatment of implants with laser therapy. The findings suggest that laser decontamination shows potential in enhancing re-osseointegration, particularly with the Er: YAG laser, which effectively decontaminated implant surfaces. However, conflicting outcomes and limitations in the evidence quality warrant caution in drawing definitive conclusions. Based on the limited available evidence, laser therapy may show a higher degree of re-osseointegration of implants than mechanical debridement.

Adjunctive Use of Lasers in Peri-Implant Mucositis and Peri-Implantitis Treatment: A Systematic Review

BACKGROUND

The aim of this systematic review is to compare the effectiveness of lasers in the treatment of implant mucositis and peri-implantitis compared to conventional treatment (non-surgical or surgical: resective or regenerative).

METHODS

Sources of PubMed, Cochrane and Google Scholar search engines were used on articles published from 1997 to 2020 in English, with selected keyword criteria applied. Nine randomized controlled trials (RCTs) were selected.

RESULTS

All included studies were considered of "high quality" according to the quality assessment scale. The comparative assessment of the RCTs was done twice for each RCT based on the type of treatment and according to wavelength. There is strong scientific evidence that, regarding non-surgical treatment, adjunct laser application can provide better results only in the short term (three months). Regarding the surgical approach, the method of decontamination plays a subordinate role. All wavelengths/applications presented similar results.

CONCLUSION

Within the limitations of this study, the adjunctive use of lasers in the treatment of peri-implant inflammation is effective for up to three months; there is no strong evidence regarding the long term benefit compared to conventional treatment.

Temperature Changes and SEM Effects of Three Different Implants-Abutment Connection during Debridement with Er:YAG Laser: An Ex Vivo Study

The study aimed to evaluate a temperature increase in, and damage to, titanium implants during flapless laser debridement. The study analyzed 15 implants with various implant–abutment connections: a two-piece implant (n = 4) with a screw abutment (IA—Implant–Abutment) and a one-piece implant with a ball type fixture (BTF, n = 4) or fix type fixture (FTF, n = 4). The implants were placed in porcine mandibles 2 mm over a bone crest to imitate a peri-implantitis. The implants were debrided in contact mode for 60 s with a Er:YAG laser at fluence of 9.95 J/cm² (G1 group: 50 mJ/30 Hz); 19.89 J/cm² (G2 group: 100 mJ/30 Hz); 39.79 J/cm² (G3 group: 200 mJ/30 Hz), or a scaler with a ceramic tip (G4 control group: 4 W/20 Hz). The temperature was measured with thermocouples at implant and abutment levels. The damage in the titanium surface (n = 3, non-irradiated implants from each type) was assessed using SEM (Scanning Electron Microscopy). The temperature increase at the implant level for the laser was higher at IA in contrast with FTF and BTF. (p < 0.05) The temperature change at the abutment level was lower for the scaler in contrast to Er:YAG laser at FTF. (p < 0.0002) Er:YAG laser didn’t increase the temperature by 10 °C at 100 mJ/30 Hz and 50 mJ/30 Hz. Based on SEM analysis, cracks occurred on the surface of two-piece implants and were more pronounced. Cracks and the melting of the titanium surface of two-piece implants cleaned with Er:YAG laser at 100 or 200 mJ were observed. The specimens treated with the ultrasonic scaler with a plastic curette showed the remaining dark debris on the titanium surface. We recommend using Er:YAG laser at 50 mJ/30 Hz during flapless implants debridement.

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.

LANAP, Periodontics and Beyond: A Review

Laser has emerged as an adjunct in several treatment modalities in dentistry in the past few decades. This less invasive bladeless technique is bringing revolutionary outcomes in a plethora of periodontal treatment procedures as well. A unique ameliorative approach termed LANAP, described as laser-assisted new attachment procedure was developed by Gregg and McCarthy. In 1990 they introduced an innovative treatment for diseases of gums incorporating pulsed neodymium yttrium aluminum garnet (Nd: YAG) 1064 nm wavelength laser (PerioLase MVP7). The LANAP concept was endorsed by Yukna et al who conducted a study according to the protocol reinforced at the1996 world workshop in periodontics, which established specific histologic criteria to prove regeneration. Yukna's histological study found that regeneration of the periodontally compromised root could be achieved by Nd: YAG laser. LANAP facilitates refurbishing of new tissues from supporting structures of the periodontium wherein the unhealthy surface of the roots exhibit pristine attachments in human beings. This paper is a review providing a detailed report of LANAP from its inception to recent advances.

Effects of an Erbium:Yttrium-Aluminum-Garnet Laser and Ultrasonic Scaler on Titanium Dioxide-Coated Titanium Surfaces Contaminated With Subgingival Plaque: An In Vitro Study to Assess Post-Treatment Biocompatibility With Osteogenic Cells

BACKGROUND

Effects of conventional ultrasonic scaler versus an erbium:yttrium-aluminum-garnet (Er:YAG) laser on titanium surfaces contaminated with subgingival plaque from patients with peri-implantitis are evaluated in terms of: 1) plaque and biocorroded titanium oxide coating removal; 2) surface change induction; and 3) residual biocompatibility toward osteoblasts.

METHODS

Subgingival plaque-coated titanium disks with a moderately rough surface were fixed with ethanol and treated with an ultrasonic scaler (metal tip) or Er:YAG laser (20.3 or 38.2 J/cm²) in non-contact mode. Fluorescent detection of residual plaque was performed. Disk surface morphology was evaluated by scanning electron microscopy. Viability, attachment, proliferation, and differentiation of Saos-2 osteoblasts on new and treated disks were assayed by propidium iodide/DNA stain assay and confocal microscopic analysis of cytoskeleton, Ki67, expression of osteopontin and alkaline phosphatase, and formation of mineralized nodules.

RESULTS

Both methods resulted in effective debridement of treated surfaces, the plaque area being reduced to 11.7% with the ultrasonic scaler and ≤0.03% with the Er:YAG laser (38.2 J/cm²). Ultrasound-treated disks showed marked surface changes, incomplete removal of the titanium dioxide (TiO₂) layer, and scanty plaque aggregates, whereas the Er:YAG laser (38.2 J/cm²) completely stripped away the plaque and TiO₂ layer, leaving a micropitted surface. Both treatments maintained a good biocompatibility of surfaces to Saos-2 osteoblasts. Air-water cooling kept disk temperature below the critical threshold of 47°C.

CONCLUSION

This study shows that an ultrasonic scaler with metal tip is less efficient than high-energy Er:YAG irradiation to remove the plaque and TiO₂ layer on anodized disks, although both procedures appear capable of restoring an adequate osseoconductivity of treated surfaces.

Evaluation of irradiation effects of near-infrared free-electron-laser of silver alloy for dental application

In the application of lasers in dentistry, there is a delicate balance between the benefits gained from laser treatment and the heat-related damage arising from laser irradiation. Hence, it is necessary to understand the different processes associated with the irradiation of lasers on dental materials. To obtain insight for the development of a safe and general-purpose laser for dentistry, the present study examines the physical effects associated with the irradiation of a near-infrared free-electron laser (FEL) on the surface of a commonly used silver dental alloy. The irradiation experiments using a 2900-nm FEL confirmed the formation of a pit in the dental alloy. The pit was formed with one macro-pulse of FEL irradiation, therefore, suggesting the possibility of efficient material processing with an FEL. Additionally, there was only a slight increase in the silver alloy temperature (less than 0.9 °C) despite the long duration of FEL irradiation, thus inferring that fixed prostheses in the oral cavity can be processed by FEL without thermal damage to the surrounding tissue. These results indicate that dental hard tissues and dental materials in the oral cavity can be safely and efficiently processed by the irradiation of a laser, which has the high repetition rate of a femtosecond laser pulse with a wavelength around 2900 nm.

Thermodynamic Effects of 3 Different Diode Lasers on an Implant-Bone Interface: An Ex-Vivo Study With Review of the Literature

The aim of this study is to assess the increase of temperature following laser irradiation with 810 nm, 980 nm, and 1064 nm diode laser wavelengths, of an implant under conditions that more closely replicate those of the human body. A 4 × 14 mm machined surface implant was placed in a porcine rib to replicate the conductivity of heat given by the bone. A peri-implant vertical defect was made that was 2 mm wide and 2 mm deep to simulate bone resorption. Two thermocouples were positioned crestally and apically on the implant surface. The tip of the laser was kept 3 mm away from the surface and continuously moved in an up-and-down and side-to-side fashion, inside the defect for 60 seconds. Initial temperatures and the time needed to reach an increase of 10°C were recorded. The experiment was repeated at room temperature and in a 37°C water bath with the following settings: 0.6 W, 0.8 W, 1 W continuous and repeated in pulsed. A critical increase of temperature of more than 10°C is reached with all lasers at 0.8 W and 1 W in continuous mode at room temperature. Only the 1064 nm diode laser reached the critical increase at 0.8 W in pulsed mode. No critical increase of temperature was registered with other settings and when the bone block was placed in a 37°C water bath. The results of this study suggest that use of these diode lasers does not cause a harmful increase in temperature when used under conditions similar to those of the human body.

The role of lasers in the treatment of peri-implant diseases: A review

We reviewed the indexed literature regarding the efficacy of laser therapy in the treatment of peri-implantitis (PI). Databases were searched using combinations of the following keywords: peri-implantitis, bone loss, photodynamic therapy, laser, and light-activated disinfection. Titles and abstracts of publications from these search results were screened to determine which studies fulfilled the eligibility criteria. Full texts of relevant studies were read and independently assessed against the eligibility criteria. The resulting 28 studies described the role of lasers in the treatment of PI. The erbium:yttrium–aluminum-garnet laser can be used to sterilize implant surfaces without damaging them. Likewise, the carbon dioxide laser can disinfect implant surfaces and enhance the bone-to-implant contact around previously infected sites. Photodynamic therapy exhibits high target specificity and can destroy pathogens associated with the etiology of PI. Laser therapy can significantly reduce levels of clinical markers of peri-implant tissue inflammation (i.e., bleeding upon probing and clinical attachment loss) without jeopardizing the integrity of the implant or alveolar bone. In conclusion, laser therapy as an adjunct to conventional mechanical debridement therapy can be used effectively for the treatment of PI.

Evaluation of laser bacterial anti-fouling of transparent nanocrystalline yttria-stabilized-zirconia cranial implant

BACKGROUND AND OBJECTIVE

The development and feasibility of a novel nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant has been recently established. The purpose of what we now call "window to the brain (WttB)" implant (or platform), is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically recurring basis without the need for repeated craniotomies. WttB holds the transformative potential for enhancing light-based diagnosis and treatment of a wide variety of brain pathologies including cerebral edema, traumatic brain injury, stroke, glioma, and neurodegenerative diseases. However, bacterial adhesion to the cranial implant is the leading factor for biofilm formation (fouling), infection, and treatment failure. Escherichia coli (E. coli), in particular, is the most common isolate in gram-negative bacillary meningitis after cranial surgery or trauma. The transparency of our WttB implant may provide a unique opportunity for non-invasive treatment of bacterial infection under the implant using medical lasers.

STUDY DESIGN/MATERIALS AND METHODS

A drop of a diluted overnight culture of BL21-293 E. coli expressing luciferase was seeded between the nc-YSZ implant and the agar plate. This was followed by immediate irradiation with selected laser. After each laser treatment the nc-YSZ was removed, and cultures were incubated for 24 hours at 37 °C. The study examined continuous wave (CW) and pulsed wave (PW) modes of near-infrared (NIR) 810 nm laser wavelength with a power output ranging from 1 to 3 W. During irradiation, the temperature distribution of nc-YSZ surface was monitored using an infrared thermal camera. Relative luminescence unit (RLU) was used to evaluate the viability of bacteria after the NIR laser treatment.

RESULTS

Analysis of RLU suggests that the viability of E. coli biofilm formation was reduced with NIR laser treatment when compared to the control group (P < 0.01) and loss of viability depends on both laser fluence and operation mode (CW or PW). The results demonstrate that while CW laser reduces the biofilm formation more than PW laser with the same power, the higher surface temperature of the implant generated by CW laser limits its medical efficacy. In contrast, with the right parameters, PW laser produces a more moderate photothermal effect which can be equally effective at controlling bacterial growth.

CONCLUSIONS

Our results show that E. coli biofilm formation across the thickness of the nc-YSZ implant can be disrupted using NIR laser treatment. The results of this in vitro study suggest that using nc-YSZ as a cranial implant in vivo may also allow for locally selective, non-invasive, chronic treatment of bacterial layers (fouling) that might form under cranial implants, without causing adverse thermal damage to the underlying host tissue when appropriate laser parameters are used. Lasers Surg. Med. 48:782-789, 2016. © 2016 Wiley Periodicals, Inc.

Evaluation of Temperature and Roughness Alteration of Diode Laser Irradiation of Zirconia and Titanium for Peri-Implantitis Treatment

OBJECTIVE

This study investigated the effects of diode laser (gallium, aluminium, arsenide [GaAlAs]) irradiation with decontamination parameters on the temperature and roughness of yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP), titanium (TI), and sandblasted large grit acid-etched titanium (SLA).

MATERIALS AND METHODS

Three groups (n = 10) of standardized disks with 5 mm diameter and 2 mm thickness were produced with Y-TZP obtained from computer-aided design and computer-aided manufacturing (CAD-CAM), machined TI and SLA. The diode laser single application (808 nm, 20 sec, 1 W, 50 Hz, t on = 100 ms, t off = 100 ms, energy density = 28.29 J/cm(2)) was performed in contact mode, on each disk. The temperature was measured by a thermosensor attached to a digital thermometer fixed to the opposite irradiated surface. The temperature gradient (ΔT) was calculated (ΔT = final temperature - initial temperature) for each group. The parameters Ra (in μm) and Sa (in μm(2)) were measured by white light confocal laser microscopy to express the surface roughness. Data of ΔT was statistically analyzed by one way ANOVA at the 95% confidence level and compared by Tukey post-hoc test (α = 0.05). Roughness data was analyzed by t test.

RESULTS

The diode laser irradiation presented the following results (ΔT value): Y-TZP = 10.3°C(B); TI = 38.6°C(A), and SLA = 26.7°C(A). The ΔT values ((°)C) of the titanium groups were higher than for the Y-TZP group. For both roughness parameters (Ra and Sa), data did not show statistical significant differences to "irradiation" factor (p > 0.05) to Y-TZP and SLA. The Ra results (in μm) were: Y-TZP (control) = 0.73 (0.55); Y-TZP (irradiated) = 0.45 (0.27); SLA (control) = 0.74 (0.23); and SLA (irradiated) = 0.99 (0.33). The Sa results (in μm(2)) were: Y-TZP (control) = 1.39 (1.05); Y-TZP (irradiated) = 0.73 (0.41); SLA (control) = 0.85 (0.08); and SLA (irradiated) = 1.27 (0.44).

CONCLUSIONS

Diode laser irradiation for peri-implantitis treatment increased both zirconia and TI temperature without surface roughness alterations.

Current concepts in the use of lasers in periodontal and implant dentistry

Lasers have various periodontal applications including calculus removal (Er: YAG, Er, Cr: YSGG lasers); soft tissue excision, incision and ablation; decontamination of root and implant surfaces; biostimulation; bacteria reduction; and osseous surgery. This paper reviews some of the major opportunities for using lasers in periodontal and implant specialty practices. The literature relating to the use of lasers for removal of the pocket epithelium, root conditioning, bacterial reduction and decontamination of infected implant surfaces is discussed, and a summary of the advantages and disadvantages of using lasers for periodontal treatment is provided.

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.

Health, Maintenance, and Recovery of Soft Tissues around Implants

BACKGROUND

The health of peri-implant soft tissues is one of the most important aspects of osseointegration necessary for the long-term survival of dental implants.

PURPOSE

To review the process of soft tissue healing around osseointegrated implants and discuss the maintenance requirements as well as the possible short-comings of peri-implant soft tissue integration.

MATERIALS AND METHODS

Literature search on the process involved in osseointegration, soft tissue healing and currently available treatment modalities was performed and a brief description of each process was provided.

RESULTS

The peri-implant interface has been shown to be less effective than natural teeth in resisting bacterial invasion because gingival fiber alignment and reduced vascular supply make it more vulnerable to subsequent peri-implant disease and future bone loss around implants. And we summarized common procedures which have been shown to be effective in preventing peri-implantitis disease progression as well as clinical techniques utilized to regenerate soft tissues with bone loss in advanced cases of peri-implantitis.

CONCLUSION

Due to the difference between peri-implant interface and natural teeth, clinicians and patients should pay more attention in the maintenance and recovery of soft tissues around implants.

Peri-implant diseases: a review of treatment interventions

The ideal management of peri-implant diseases focuses on infection control, detoxification of implant surfaces, regeneration of lost tissues, and plaque-control regimens via mechanical debridement (with or without raising a surgical flap). However, a variety of other therapeutic modalities also have been proposed for the management of peri-implantitis. These treatment strategies encompass use of antiseptics and/or antibiotics, laser therapy, guided bone regeneration, and photodynamic therapy. The aim of this article was to review indexed literature with reference to the various therapeutic interventions proposed for the management of peri-implant diseases.

Thermal effects on zirconia substrate after Er,Cr:YSGG irradiation

OBJECTIVE: The objective of the present study was to investigate the thermal effects of Er,Cr:YSGG laser irradiation (1.5W/20Hz) on yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP). MATERIAL AND METHOD: Fifteen disks of Y-TZP (AS Technology TitaniumFIX, São José dos Campos, Brazil) with 5 mm diameter and 3 mm high standardized with CAD-CAM were used. The Y-TZP disks were randomized in three groups (n=5): Y-TZP-G1 = control (no laser treatment); Y-TZP-G2 = Y-TZP + Er,Cr:YSGG laser (air-water cooling proportion 80%/25%); Y-TZP-G3 = Y-TZP + Er,Cr:YSGG laser (air-water cooling proportion 80%/0%). A thermopar (SmartMether, Novus, Porto Alegre, RS, Brazil) was attached to a digital thermometer (SmartMether, Novus, Porto Alegre, RS, Brazil) fixed to the opposite irradiated surface. The temperature gradients (ΔT) were calculated (ΔT = Final Temperature - Initial Temperature) for each group. Values were statistically analyzed by one-way ANOVA at the 95% confidence level and compared by Tukey post-hoc test (α=0.05) for each material. One sample of each group was analyzed by confocal white light microscopy. RESULT: The ANOVA test showed significant differences for the factor "laser" (p<.001). The temperature gradients (ΔT value) showed the following results: Y-TZP-G1 = 0 ºC; Y-TZP-G2 = -1.4 ºC and Y-TZP-G3 = 21.4 ºC. The ΔT values (ºC) of the non-refrigerated group were higher than the refrigerated group. The roughness value (Ra) ranged from 4.50 to -33.65 µm. CONCLUSION: The water refrigeration for Er,Cr:YSGG irradiation is essential to avoid thermal increase in the Y-TZP.

Re-stability of dental implants following treatment of peri-implantitis

It is hypothesized that active treatment of peri-implantitis (PI) leads to re-stabilization of dental implants. The aim was to assess whether or not dental implants can re-stabilize following treatment of PI. To address the focused question, MEDLINE/PubMed and Google-Scholar databases were explored from 1977 up to and including August 2013. Any disagreements between the authors were resolved via discussion. Articles published only in English were included. Hand searching was also performed. Thirteen experimental studies were included. The treatment regimes adopted in these studies comprised of antibiotic therapy, guided bone regeneration (GBR), laser therapy, use of bone matrix proteins with membrane, conventional flap surgery and mechanical debridement. In four studies, GBR promoted new bone formation; whereas two studies showed photosensitization therapy (in combination with either mechanical debridement or GBR) to regenerate bone around peri-implant defects. Six studies reported that mechanical debridement in conjunction with antibiotic therapy promoted re-stability of dental implants. In one study, recombinant human bone matrix protein-2 with a collagen membrane helped promote re-stabilization of dental implants. New bone formation may occur to some extent around dental implants following treatment for PI; however, a "complete" re-stability may be difficult to achieve without GBR.