**2. Treatment of peri-implantitis**

Peri-implantitis is a complex multi-microbial and multifactorial disease, thus, therapy continues to be a challenge. It has been suggested that peri-implantitis surgical therapy is superior to non-surgical one [49]. Implant surface decontamination is an important but at the same time difficult step in peri-implantitis treatment. The goal of implant surface decontamination is to completely remove all causative bacteria from the implant surface preparing the tissue for regeneration and re-osseointegration [12]. Considering the possible role of micro- and micro-design on peri-implantitis initiation, special care should be taken in the process of implant surface decontamination.

The removal of microbes from the implant surface may cause possible implant surface damage. As a result of surface damage, surface chemical oxide layer changes could lead to induced corrosion, acidic pH, changes in surface roughness, plaque accumulation, and osteoclast activation impairing implants biocompatibility [50].

*The Effect of Implant Surface Design and Their Decontamination Methods in Peri-Implantitis… DOI: http://dx.doi.org/10.5772/intechopen.99753*

Additionally, different methods of decontamination could generate mechanical or chemical processes on implant surfaces releasing titanium' ions and particles, and promoting the pathogenic biofilm growth on treated surfaces as well [45].

Although there is no standardized protocol for peri-implantitis treatment, many methods of implant surface decontamination have been proposed including mechanical methods, chemical methods, laser, photodynamic therapy, and implantoplasty, usually combined with systemic antibiotics administration [51–60]. Accordingly, this chapter aimed to determine which method of implant surface decontamination could be successfully performed assessing comparably if implant topography could have influenced the decontamination method choice in peri-implantitis treatment.

#### **2.1 Mechanical and chemical methods of implant surface decontamination**

The removal of biofilms and calculus is essential for long-term clinical success and bone regeneration [12]. Therefore, mechanical removal of granulation tissue and surface cleaning presents the first steps in peri-implantitis or periodontal therapy. Ideal mechanical methods should be capable of completely removing deposits and bacteria along with their products from the implant surface without altering or damaging implant surface integrity and biocompatibility, or affecting the implanttissue interface. Due to implant surface macro- and micro-design as well as bacterial characteristics, it is difficult to achieve long-term results using a mechanical method alone. Therefore, this method is usually combined with chemical methods, photodynamic or laser therapy.

Several instruments such as curettes and brushes have been proposed for mechanical implant surface decontamination. Metal (stainless steel) curettes, burs and conventional sonic and ultrasonic scalers, have been shown to damage the smooth or rough (TPS and SLA) implant surface leaving behind the debris by removing the surface coating, threads and edges. Nevertheless, these instruments are only used when smooth surface of implant, implantoplasty, is required [61]. Titanium curettes were also advised to be used with caution due to their tendency to leave marks on the implant surface increasing the depth of the surface roughness and in this way causing an inability to effectively remove biofilm [62]. Plastic curettes did not leave any surface scratches on different implants surfaces. However, their limited flexibility and size resulted in incomplete plaque removal in screw-type implants [63]. Even when combined with chemical methods such as chlorhexidine gluconate (CHX), plastic curette was not effective in biofilm removal from Osseotite® or SLA titanium disks [64] thereby only being recommended for use during maintenance care [65].

Peri-implantitis treatment performing the Vector system improved oral hygiene, yet showing no improvement in clinical parameters compared to carbon curettes after six months of follow-ups [66]. According to systematic reviews, Vector systems with carbon tips efficiently removed biofilms from polished titanium and SLA surfaces. Hence, the potential to produce SLA and TPS surface damage was found to be a drawback, and could be possible explanation for poor clinical outcomes [61, 63, 67].

The market offers a variety of rotating titanium brushes that are successfully used in combination with other chemical agents or physical methods for implant surface decontamination (**Figure 1**). Rotating brushes effectively clean SLA, TiUnite, and OsseoSpeed surfaces without compromising their properties [67]. Contrary to this, *in vitro* study demonstrated that titanium brushes could create titanium surface craters with remaining titanium particles on SLA surface. The significance of this result must be interpreted carefully since this study was conducted under *in vitro* conditions, the coating surfaces

#### **Figure 1.**

*Mechanical methods of implant surface decontamination by performing two different titanium brushes (a, b,) and graphite curette (c).*

#### *The Effect of Implant Surface Design and Their Decontamination Methods in Peri-Implantitis… DOI: http://dx.doi.org/10.5772/intechopen.99753*

were not contaminated, and the treatment was done on "sterile" surfaces [68]. In a recent randomized clinical trial (RCT), rotating titanium brushes combined with 3% H2O2 during regenerative surgical procedures of peri-implantitis significantly reduced both PPD and BOP after 12 months from the surgery [69]. The titanium brushes could be proposed for implant surface decontamination during the surgery.

Other mechanical methods of implant surface decontamination, air powder-water sprays, have not shown to be superior in terms of improvement in clinical parameters and possible re-osseointegration compared to other mechanical methods. Recent *in vitro* study revealed that air-power-water spray was not effective in removing biofilms from titanium surfaces, grades 4 and 5, acid-etched, sandblasted, or functionally anodized surfaces compared to electrolytic methods that completely eradicate biofilms from treated surfaces [70]. Furthermore, air-powder system properties such as water flow, powder medium, air pressure, and exposure time seemed to influence biofilm removal and implant surface changes. There was a significant difference in the effectiveness of the medium for hydroxyapatite/tricalcium phosphate and hydroxyapatite, while the cleaning effect was less pronounced on titanium dioxide and phosphoric acid. In addition, amino acid glycine powder effectively removed microbes from implants without altering implant surface as compared to classical sodium bicarbonate powder. It was found that the sodium bicarbonate powder left craters and abrasive residue on the surface. As a result of this, the immune system may be impaired causing an inflammatory response of the tissue [67].

Implantoplasty is another mechanical method of implant surface decontamination that is usually used during surgical peri-implantitis therapy to smoothen the supracrestal exposed implant surface (**Figure 2**). Whenever there is a persistent supracrestal bone defect (Class II bone defect, classified by Schwarz [71]), implantoplasty appears to be the most effective treatment. Among the benefits of implantoplasty there is a very low bacteria adhesion and recolonization rate.

Due to the implant surface roughness, it could not be possible to remove bacteria and their waste products completely. Therefore, it is recommended to be combined with antiseptics and antibiotics. Various chemical agents such as chlorhexidine gluconate (CHX), hydrogen peroxide (H2O2), citric acid, and phosphoric acid have been proposed as means to decontaminate titanium implant surfaces in both non-surgical and surgical therapies.

The CHX is a commonly used antiseptic agent that is considered a 'gold standard' in various treatment procedures. It is a time-dependent chemical agent which exhibits both bactericidal and bacteriostatic effects. With increasing CHX concertation, in both pure titanium discs and titanium-zirconium alloy discs there was a decrease in the mean number of colony-forming units indicating antibacterial dose–response and biofilm control [72]. Even so, the clinical and microbiological outcomes in one of RCTs had not shown statistical differences when two CHX concentrations (2% vs. 0.12% CHX + 0.5% CPC) were used for the decontamination of commercially available implant surfaces during peri-implantitis resective surgery [73]. These results were consistent with our prior published study in which implant surface decontamination was performed by applying 1% gel of CHX followed by saline solution irrigation during regenerative surgery. Our study concluded that this chemical procedure had insufficient effectiveness in clinical and microbiological results [57]. Under *in vitro* conditions, CHX can remain on implant surfaces gradually releasing and acting within 24 hours against bacteria without harming the surface. Nevertheless, a special caution needs to be taken during implant surface decontamination due to CHX cytotoxic effects on osteoblastic, endothelium, and fibroblastic cells [74]. Irrigation by saline solution for

#### **Figure 2.**

*Implantoplasty as a mechanical method for implant surface decontamination: Exposed implant surface (a), implantoplasty procedure (b), smooth implant surface (c).*

#### *The Effect of Implant Surface Design and Their Decontamination Methods in Peri-Implantitis… DOI: http://dx.doi.org/10.5772/intechopen.99753*

approximately a minute could alleviate the negative effect of CHX; however, it should be noted that this irrigation might reduce CHX-substantivity. Furthermore, because of CHX's low cleaning capacity, gauze soaked in saline solution should be taken after CHX application to mechanically remove debris and death cells that might act as a substrate for recolonization, and consequently, disease reappearance.

The use of adjuvant systemic or local antibiotic therapy could also be affected by implant surface topography in peri-implantitis therapy. A successful treatment outcome was documented in only 45% of treated implants by Carcuac et al. In this study, 79% of implants with non-modified surface features and 34% of implants with modified surfaces had successful treatment after peri-implant surgery [75]. In the Heitz-Mayfield et al. study, a significant improvement of clinical parameters was achieved within 12 months after an open-flap surgical procedure of moderate and advance peri-implantitis followed by adjuvant systemic antibiotics administration (amoxicillin and metronidazole) and antiseptic solution (0.12% CHX). Approximately 47% of implants with various surface topographies completely resolved inflammation postoperatively. However, within 12 months of implant surgery, bone continues to lose on implants with porous anodized, titanium plasma-sprayed, and machine surfaces [54]. Systemic antibiotics had limited penetration into the biofilm attached to the titanium implant surface. These findings would support the recommendation that implant surface should be carefully evaluated prior to adjuvant systemic antibiotics administration. Apart from this, broad-spectrum antibiotics' excessive use, their side effects, and allergic reactions have led to bacterial-resistance development, thus additional care should be taken in their administration.

In order to overcome these drawbacks of chemical and mechanical methods, novel methods such as laser or photodynamic therapy were introduced to improve implant surface decontamination.

#### **2.2 Application of laser and photodynamic therapy in peri-implantitis treatment**

#### *2.2.1 Laser use in peri-implantitis therapy*

In the late 1980's, a laser system was introduced in dentistry [76] increasing laser popularity in dental implantology considerably. Due to the laser's capacity to achieve satisfactory cutting, induce good coagulation, and antibacterial effect, the laser is widely used in dental implantology for the safe second stage surgery of submerging implants, peri-implant soft tissue plastic surgery, and implant surface decontamination. Lasers have been described to possess ability to facilitate implant site preparation enhancing bone healing and osseointegration [56, 77, 78].

The lasers' use in non-surgical and surgical peri-implantitis therapy was widely examined, especially its effects on implant surface decontamination and re-osseointegration. Titanium implant surfaces have greater absorption characteristics resulting in the surface overheating and alteration, so special consideration should be given when they are exposed to the laser. A literature review has recommended a few types of lasers for decontaminating implant surfaces [56].

Er: YAG laser is suggested for successful implant surface decontamination with a tendency to achieve re-osseointegration (**Figure 3**). Safe irradiation settings for this laser should be above 300 mJ/10 Hz for 10s achieving efficiently a bactericide effect, and not increasing implant temperature or altering the surface of polished or SLA implants [79]. Favorable long-term outcomes following treatment of peri-implantitis with Er: YAG lasers were observed in a few clinical studies [80, 81]. A case report

**Figure 3.** *Implant surface decontamination by performing laser therapy in the treatment of early peri-implantitis stage (LightWalker, Fotona, Slovenia) (a) implant radiography before laser therapy (b).*

study on zirconium implants found that Er: YAG led to improvements in clinical parameters (PPD and BOP) six months after peri-implantitis surgery [82].

CO2 (carbon dioxide laser) and gallium-aluminum-arsenide lasers (one of the diode lasers) are introduced as safe methods for implant decontamination with antibacterial effects. Depending on implant surface topography, special attention should be taken considering the time of laser exposure, power, and irradiation mode (continues, CW, or pulse, PW, mode). *In vitro* study had shown that CO2 and diode laser with lower settings and at 810 nm wavelength could effectively destroy *P. gingivalis* on zirconium and titanium surfaces, whereas a higher setting of diode laser is required in order to eliminate *S. sanguis* and *P. gingivalis* adhered to zirconium surface [83]. Furthermore, diode laser of 810 nm and 4 W power showed a slight alteration on moderate roughness sandblasting implant surface compared to 3 W power laser settings [68]. On the polished and SLA implant surfaces, CO2 laser set in CW mode, up to 4 W, and diode laser set at 810 nm, CW mode, and 1 W–3 W showed no alteration [79], and thereby could be recommended as safe implant surface decontamination method in peri-implantitis treatment. To determine the influence of these recommended parameters on implant surface decontamination methods for different peri-implantitis stages and implant topographies, further experiments and clinical studies are required.

On the other hand, Nd: YAG lasers could induce surface alteration by causing surface melt and increasing its roughness. This type of laser is contraindicated for any dental implant surgical interventions. Application of diode lasers with other wavelengths or fiber systems should be used with special care as the laser light directly contacting the bone may cause thermal damage.

#### *2.2.2 Photodynamic therapy assessment in peri-implantitis therapy*

A novel antimicrobial treatment modality, photodynamic therapy (PDT) was introduced for the various oral infection treatments. The PDT mechanism is based on a suitable wavelength low-energy single-frequency diode laser activating a photoactive material (photosensitiser) that binds a target cell. In this mechanism, the photochemical oxygen-dependent reaction is induced producing very reactive superoxide radicals, such as single oxygen that causes photogenic species death.

Studies demonstrated the PDT efficiency in treating peri-implantitis with a particular emphasis on implant surfaces decontamination using the procedure (**Figure 4**). *The Effect of Implant Surface Design and Their Decontamination Methods in Peri-Implantitis… DOI: http://dx.doi.org/10.5772/intechopen.99753*

#### **Figure 4.**

*Photodynamic therapy (HELBO, photodynamic systems GmbH, Bredent medical GmbH & Co KG) performed for implant surface decontamination during peri-implantitis surgery: Photosensitizer- phenothiazine chloride application (HELBO® blue photosensitizer) on implant surface and surrounding tissue (a) followed by diode laser irradiation with 2D fiber optic probe (b).*

A few *in vitro* studies have demonstrated a reduction and elimination of bacteria from implant surfaces performing PDT [58, 60, 84, 85]. Haas et al. achieved a significant reduction in number of periodontopathogen bacteria (*P. gingivalis, P. intermedia* and *A. actinomycetemcomitans*) from machined, plasma-flame-sprayed, etched, and hydroxyapatite-coated implant surfaces [85]. Other *in vitro* studies also showed a significant reduction in the total number of bacteria on titanium implants (Bredent, Sedan, Germany) [58], zirconium implants [84], and anodized rough implant surface (TiUnite, Nobel) without any implant surface changes. Considering implant topography on

zirconium surfaces, PDT has revealed greater efficiency in eliminating a total number of bacteria compared to titanium surfaces [86].

In our previous clinical study, the positive effects of PDT on microbiological reduction and clinical outcomes improvement after peri-implantitis surgery were assessed three months postoperatively [57]. PDT proved to be a very effective decontamination method for various titanium implant surfaces according to the research. Additionally, the further follow-up observation aimed to show the maintenance results achieved by performing PDT, six and 12 months postoperatively. Patients' inclusion criteria, follow-up parameters and surgical treatment procedures have previously been reported in detail [57]. In brief, the surgical regenerative treatment procedure was performed on each patient with early or moderate peri-implantitis. During the surgery, after careful mucoperiosteal flap elevation, granulation tissue removal, patients were randomly divided into two groups. In one group (21 systemically healthy patients), PDT (HELBO, Photodynamic Systems GmbH, Wels, Austria) was performed for implant surface decontamination, while in another group (19 systemically healthy patients), CHX was used as a chemical decontamination method. Clinical and microbiological outcomes were used to assess treatment success. Microbiological samples were taken both from the pockets around the implant prior to any procedure and during follow-ups, and during surgical procedures before and immediately after surface decontamination. Samples were cultured and biochemically analyzed using standard procedures for anaerobic bacteria diagnosis. Detailed microbiological sample collecting and analyses were explained in the previous study [57]. The results were examined using SPSS 20.0.

Different pathogenic bacteria (**Table 1**) were isolated either from various examined implant surfaces (**Table 2**) during the surgical therapy or from the peri-implant pockets prior to any treatment. The presence of *S. aureus* on implant surfaces confirmed the earlier statements of bacteria affinity to colonize the titanium implant surface [41, 42]. This could emphasize the possible influence of *S. aureus* on the onset and progression of peri-implantitis. Furthermore, *C. albicans* was isolated from peri-implant pockets indicating a possible role of *Candida species* in peri-implantitis onset. This observation reported that mechanical implant surface decontamination followed by PDT along with regenerative surgical therapy successfully reduced pathogenic bacteria (**Table 1**) and improved clinical parameters in terms of PPD and BOP reduction three, six and 12 months postoperatively (**Table 3**). Similar clinical parameters' improvements and pathogen reduction in peri-implantitis treatment were recorded in other clinical and experimental studies [87–89]. Performing either PDT or titanium brushes combined with PDT for implant surface decontamination in *in vitro* study, *S. aureus* was successfully reduced from polished, SLA, and SLAactive implant surfaces [41].

One of the goals in peri-implantitis therapy is the total elimination of pathogens allowing the tissue to regenerate. As a final result, re-osseointegration is considered to be an essential outcome of peri-implantitis treatment that may be affected by different implant surface decontamination protocols. Experimental outcomes demonstrated partial peri-implant defect reconstruction and reosseointegration after performing PDT for SLA implant surface decontamination combined with or without guide bone regeneration (GBR) and collagen membrane [90]. One of the earliest experimental studies evaluated the ability of PDT to re-osseointegrate peri-implantitis defects around a variety of implant surfaces utilizing GBR and polytetrafluoroethylene membrane [91]. Study results indicated that the TPS surface showed a greater re-osseointegration rate than HA

*The Effect of Implant Surface Design and Their Decontamination Methods in Peri-Implantitis… DOI: http://dx.doi.org/10.5772/intechopen.99753*


*¥ Statistically significant change from baseline, three, six and 12 months after therapy, and also before and after implant surface decontamination during surgical procedure by Cochran Test, p < 0.05;*

*T0 – isolated bacteria form peri-implant pocket before any treatment; T1, T2, T3- isolated bacteria form peri-implant pocket three, six and 12 months postoperatively; S1 and S2– isolated bacteria from implant surface decontamination before and immediately after decontamination followed by PDT during surgical therapy;* 

*P.g.* **-** *Porphyromonas gingivalis; P.i.- Prevotella intermedia; P.s. - Peptostreptococcus spp.; F.n.- Fusobacterium nucleatum; A.n.- A. naeslundii; V.- Veillonella spp.; S.a.- Staphylococcus aureus; A.o.- A. odontolyticus.*

#### **Table 1.**

*Number (n) of culture-positive implants at baseline and culture-negative after selected bacteria decontamination with photodynamic therapy.*


#### **Table 2.**

*Percentage of various implant topographies decontaminated by photodynamic therapy.*


#### **Table 3.**

*Mean pocket probing depth (PPD) ± SD, and mean bleeding on probing (BOP) for each implant at baseline and three, six and 12 months later.*

implant surface. Based on these findings, PDT may have potential effects in periimplantitis treatment with a potential to lead to re-osseointegration. Different bone grafts application in filling peri-implant defects might contribute to clinical outcomes improvement that may be an explanation for earlier interpreted clinical results.

Nevertheless, decontamination of implant surfaces aims to recreate the conditions that existed before infection or after the implant was placed and integrated. Hence, in order to achieve re-integration, and considering implant topography as well, both micro- and macro-design need to be almost identical to what existed before the implant was placed enhancing osteoblast stimulation and creating re-novel BIC. Accordingly, peri-implantitis requires special consideration in determining the appropriate decontamination methods since there are no standard treatment protocols. Consequently, more clinical trials are required to determine the efficacy of proposed decontamination methods for implant surfaces, with or without regenerative and resective methods.
