**1. Introduction**

Antimicrobial photodynamic therapy (aPDT) is becoming a treatment option in dental medicine in different areas such as the diagnosis of malignant transformation of oral lesions, the treatment of head and neck cancer, as well as the treatment of bacterial and fungal infections [1, 2].

In periodontology, the conventional therapeutic approach for treating periodontal diseases consists of mechanical cleaning combined with chemical decontamination, or the use of antimicrobial therapy which can be applied systemically or locally. The mechanical debridement has its own limitations in removing all the infections, such as the difficulties in reaching deep pockets and, as a result, the etiological factors continue to damage the periodontal ligament. Also, when mechanical debridement is used frequently, it can cause damage of the root surface [3].

The limitations of the conventional periodontal therapy have shifted the focus towards aPDT, as an effective alternative treatment for periodontal diseases [4–8]. aPDT is having many advantages over conventional therapy. The main advantage is the fact that photosensitizer can be placed directly into the periodontal pocket and then activated with an optical fiber tip in order to kill microbial cells, without damaging the host tissues. This makes aPDT a safe procedure against periodontal microbiota [9, 10].

Many studies have demonstrated potential improvements after the use of aPDT in conjunction with mechanical debridement [11–13]. However, there are several studies that report different results [5, 14–16]. Atieh suggested as a result of his meta-analysis, potential improvements after aPDT combined with scaling and root planning in probing periodontal pocket depth (PPD) reduction and greater clinical attachment level (CAL) gain [13]. Similarly, in their study Sgolastra et al. reported that the combination of aPDT and conventional treatment provides additional benefits by reducing the PPD and increasing the CAL [11].

In endodontics, aPDT is used for the disinfection of the root canal. Conventional endodontic treatment consists of a combination of mechanical cleaning and shaping of the canals, the use of disinfecting solutions for irrigation and the placement of medicaments in between appointments. Sometimes, due to the root canal anatomy it is difficult to completely disinfect the canals by using only mechanical and chemical decontamination methods [17, 18]. aPDT demonstrated promising results as an adjunct therapy for the root canal disinfection in many studies. Raymond et al. [17] evaluated the efficacy of the combination of conventional treatment with photodynamic therapy *in vitro*. Their results showed that the combination of both therapies is more effective than the use of traditional treatment alone. Rios et al. [19] in their study used a combination of light-emitting diode (LED) as a light source and toluidine blue O dye as a photosensitizer. They suggested that photodynamic therapy can be used as an adjunctive antimicrobial procedure in endodontics. Similarly in their clinical study, Bago et al. [20] demonstrated that aPDT when used as an addition to the conventional mechanical and chemical root canal cleaning, can lead to significantly more reduction of the bacteria and in some samples the total elimination of the bacteria.

Photodynamic therapy is used also in oral and maxillofacial surgery due to its potential to be used as an anti-cancer treatment and its antimicrobial potential. Oral squamous cell carcinomas (SCC) are the most frequent tumors in the oral cavity [21]. Up to date the traditional methods for treating SCC have not been very successful in increasing the 5-year survival rate. Furthermore they cause different side effects such as mouth sore, jaw pain and difficulties in chewing or swallowing [22].

One of the developing factors of oral SCC are considered to be the pre-malignant lesions such as erythroplakias and dysplastic leukoplakias. Around half of oral SCC cases are associated with leukoplakias [23]. The potential therapeutic possibilities of photodynamic therapy are not limited only for oral SCC and other head and neck cancers, but also against pre-malignant, primary, recurrent and metastatic lesions [24, 25]. PDT when compared to conventional treatments of these lesions, has an advantage due to its selective tumor destruction and minimal invasiveness without affecting the healthy tissues. In addition, it can combined with conventional therapy to increase the overall treatment success [26].

The PDT antimicrobial potential in oral and maxillofacial surgery, is mostly used for the disinfection of soft tissue or bone during surgical interventions, as a preventive measure. In a study done by Neugebauer et al. [27] it was demonstrated that use of aPDT caused significantly lower incidence of alveolar ostitis. In a another study it was concluded that the effect of photodynamic therapy is almost the same as the effect of 2.5% NaOCl without causing adverse effects on surrounding tissues on periapical lesion model *in vitro* [28]. Batinjan et al. [29] showed that

**151**

*Evaluation of the Antimicrobial Efficacy of Different Types of Photodynamic Therapy…*

ture after the removal of the impacted third mandibular molar.

aPDT causes reduced postoperative wound swelling and decreased wound tempera-

PDT has recently also been used as an adjuvant therapy for the treatment of medication-related osteonecrosis of jaws (MRONJ), that is highly related to bisphosphonate-related osteonecrosis of the jaw (BRONJ). In a study done by Minamisako et al. [30], it was suggested that both low level laser therapy (LLLT) and PDT are beneficial in the clinical management of the MRONJ. Similarly, Rugani et al. [31] concluded that photodynamic therapy can be used as treatment option in the early stages of BRONJ or as an adjunct therapy when surgical intervention is indicated.

In 1978. Brånemark presented two-stage threaded titanium implants in a root-form [32]. The concept of osseointegration of the implants was first brought during the 1950s and 1960s after observing bone growth in contact with titanium. Brånemark defined osseointegration as: "A direct connection between living bone and a load-carrying endosseous implant at the light microscopic level." [33]. Since then, dental implants have become a long-term reliable treatment option for

replacing missing teeth [34]. An ideal implant should have the following properties: biocompatibility, adequate toughness, strength, corrosion resistance, facture and

The "gold standard" of dental implants are considered to be the implants produced from titanium and its alloys. Titanium has excellent biocompatibility and it was shown that long term surgical rates of titanium implants are excellent [38, 39]. However, due to their dark gray color sometimes the implants can reflect through the peri-implant soft tissue. This poses an esthetic challenge especially when a thin biotype of gingiva is present or when there is a resorption of the buccal lamina [39, 40]. Due to these reasons, many scientists have shifted their focus into producing

The infection around dental implants can be presented as peri-implant mucositis or peri-implantitis. Peri-implant mucositis is a reversible inflammatory process and it affects only the soft tissues around the dental implant. This is followed by reddening, swelling and bleeding on probing [42]. Peri-implantitis on the other hand affects both soft and hard tissues around the implant and as a result loss of supporting bone occurs [43]. The microbial etiology of peri-implantitis is well documented in literature [44]. The microorganisms found in peri-implantits are very similar to those found in advanced periodontitis [45, 46]. Most of them are spirochetes and non-motile anaerobic Gram-negative bacteria such as: *Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans,, Prevotella intermedia, Tannarella forsythia, Treponema denticola* etc. [47]. In the oral cavity the implant surfaces are colonized very rapidly by the bacteria, which leads to the formation of a bacterial biofilm on the implant surface. When peri-implanitits is in its early stages, there are no significant symptoms and most of the time it is diagnosed during routine dental check-up. It is of great importance to diagnose peri-implanitits in its early stages in order to prevent the progression of the

disease and increase the chances for good osseointegration [48].

According to Teughels et al. [49], the quantity and quality of plaque formation and bacterial adhesion on implant surfaces is influenced by the chemical composition, and the surface roughness of the implant. Rough surfaces and those with greater surface free energy, accumulate more plaque. Furthermore, initial bacterial adhesion is attracted more to surfaces with high wettability and pits and grooves in the roughened surfaces. The formation of bacterial plaque in these surfaces is difficult to remove.

To date, many treatment methods have been proposed for treating peri-implantitis. They can be grouped in two categories: resective and regenerative therapies [50].

*DOI: http://dx.doi.org/10.5772/intechopen.94268*

**1.1 Peri-implant diseases and aPDT**

wear resistance [35–37].

ceramic implants [41].

#### *Evaluation of the Antimicrobial Efficacy of Different Types of Photodynamic Therapy… DOI: http://dx.doi.org/10.5772/intechopen.94268*

aPDT causes reduced postoperative wound swelling and decreased wound temperature after the removal of the impacted third mandibular molar.

PDT has recently also been used as an adjuvant therapy for the treatment of medication-related osteonecrosis of jaws (MRONJ), that is highly related to bisphosphonate-related osteonecrosis of the jaw (BRONJ). In a study done by Minamisako et al. [30], it was suggested that both low level laser therapy (LLLT) and PDT are beneficial in the clinical management of the MRONJ. Similarly, Rugani et al. [31] concluded that photodynamic therapy can be used as treatment option in the early stages of BRONJ or as an adjunct therapy when surgical intervention is indicated.

#### **1.1 Peri-implant diseases and aPDT**

*Photodynamic Therapy - From Basic Science to Clinical Research*

benefits by reducing the PPD and increasing the CAL [11].

of the bacteria and in some samples the total elimination of the bacteria.

therapy to increase the overall treatment success [26].

Photodynamic therapy is used also in oral and maxillofacial surgery due to its potential to be used as an anti-cancer treatment and its antimicrobial potential. Oral squamous cell carcinomas (SCC) are the most frequent tumors in the oral cavity [21]. Up to date the traditional methods for treating SCC have not been very successful in increasing the 5-year survival rate. Furthermore they cause different side effects such as mouth sore, jaw pain and difficulties in chewing or swallowing [22]. One of the developing factors of oral SCC are considered to be the pre-malignant lesions such as erythroplakias and dysplastic leukoplakias. Around half of oral SCC cases are associated with leukoplakias [23]. The potential therapeutic possibilities of photodynamic therapy are not limited only for oral SCC and other head and neck cancers, but also against pre-malignant, primary, recurrent and metastatic lesions [24, 25]. PDT when compared to conventional treatments of these lesions, has an advantage due to its selective tumor destruction and minimal invasiveness without affecting the healthy tissues. In addition, it can combined with conventional

The PDT antimicrobial potential in oral and maxillofacial surgery, is mostly used for the disinfection of soft tissue or bone during surgical interventions, as a preventive measure. In a study done by Neugebauer et al. [27] it was demonstrated that use of aPDT caused significantly lower incidence of alveolar ostitis. In a another study it was concluded that the effect of photodynamic therapy is almost the same as the effect of 2.5% NaOCl without causing adverse effects on surrounding tissues on periapical lesion model *in vitro* [28]. Batinjan et al. [29] showed that

microbiota [9, 10].

The limitations of the conventional periodontal therapy have shifted the focus towards aPDT, as an effective alternative treatment for periodontal diseases [4–8]. aPDT is having many advantages over conventional therapy. The main advantage is the fact that photosensitizer can be placed directly into the periodontal pocket and then activated with an optical fiber tip in order to kill microbial cells, without damaging the host tissues. This makes aPDT a safe procedure against periodontal

Many studies have demonstrated potential improvements after the use of aPDT in conjunction with mechanical debridement [11–13]. However, there are several studies that report different results [5, 14–16]. Atieh suggested as a result of his meta-analysis, potential improvements after aPDT combined with scaling and root planning in probing periodontal pocket depth (PPD) reduction and greater clinical attachment level (CAL) gain [13]. Similarly, in their study Sgolastra et al. reported that the combination of aPDT and conventional treatment provides additional

In endodontics, aPDT is used for the disinfection of the root canal. Conventional endodontic treatment consists of a combination of mechanical cleaning and shaping of the canals, the use of disinfecting solutions for irrigation and the placement of medicaments in between appointments. Sometimes, due to the root canal anatomy it is difficult to completely disinfect the canals by using only mechanical and chemical decontamination methods [17, 18]. aPDT demonstrated promising results as an adjunct therapy for the root canal disinfection in many studies. Raymond et al. [17] evaluated the efficacy of the combination of conventional treatment with photodynamic therapy *in vitro*. Their results showed that the combination of both therapies is more effective than the use of traditional treatment alone. Rios et al. [19] in their study used a combination of light-emitting diode (LED) as a light source and toluidine blue O dye as a photosensitizer. They suggested that photodynamic therapy can be used as an adjunctive antimicrobial procedure in endodontics. Similarly in their clinical study, Bago et al. [20] demonstrated that aPDT when used as an addition to the conventional mechanical and chemical root canal cleaning, can lead to significantly more reduction

**150**

In 1978. Brånemark presented two-stage threaded titanium implants in a root-form [32]. The concept of osseointegration of the implants was first brought during the 1950s and 1960s after observing bone growth in contact with titanium. Brånemark defined osseointegration as: "A direct connection between living bone and a load-carrying endosseous implant at the light microscopic level." [33]. Since then, dental implants have become a long-term reliable treatment option for replacing missing teeth [34]. An ideal implant should have the following properties: biocompatibility, adequate toughness, strength, corrosion resistance, facture and wear resistance [35–37].

The "gold standard" of dental implants are considered to be the implants produced from titanium and its alloys. Titanium has excellent biocompatibility and it was shown that long term surgical rates of titanium implants are excellent [38, 39]. However, due to their dark gray color sometimes the implants can reflect through the peri-implant soft tissue. This poses an esthetic challenge especially when a thin biotype of gingiva is present or when there is a resorption of the buccal lamina [39, 40]. Due to these reasons, many scientists have shifted their focus into producing ceramic implants [41].

The infection around dental implants can be presented as peri-implant mucositis or peri-implantitis. Peri-implant mucositis is a reversible inflammatory process and it affects only the soft tissues around the dental implant. This is followed by reddening, swelling and bleeding on probing [42]. Peri-implantitis on the other hand affects both soft and hard tissues around the implant and as a result loss of supporting bone occurs [43]. The microbial etiology of peri-implantitis is well documented in literature [44]. The microorganisms found in peri-implantits are very similar to those found in advanced periodontitis [45, 46]. Most of them are spirochetes and non-motile anaerobic Gram-negative bacteria such as: *Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans,, Prevotella intermedia, Tannarella forsythia, Treponema denticola* etc. [47]. In the oral cavity the implant surfaces are colonized very rapidly by the bacteria, which leads to the formation of a bacterial biofilm on the implant surface. When peri-implanitits is in its early stages, there are no significant symptoms and most of the time it is diagnosed during routine dental check-up. It is of great importance to diagnose peri-implanitits in its early stages in order to prevent the progression of the disease and increase the chances for good osseointegration [48].

According to Teughels et al. [49], the quantity and quality of plaque formation and bacterial adhesion on implant surfaces is influenced by the chemical composition, and the surface roughness of the implant. Rough surfaces and those with greater surface free energy, accumulate more plaque. Furthermore, initial bacterial adhesion is attracted more to surfaces with high wettability and pits and grooves in the roughened surfaces. The formation of bacterial plaque in these surfaces is difficult to remove.

To date, many treatment methods have been proposed for treating peri-implantitis. They can be grouped in two categories: resective and regenerative therapies [50].

The main goal of resective treatments is to eliminate the etiological factors of periimplanittis and maintain optimal conditions. These treatments are mainly done by cleaning and decontaminating implant surfaces. Regenerative treatments aim to reconstruct the pre-existing hard and soft tissues by using bone substitute grafts, membranes and growth factors [50, 51]. Resective treatment of peri-implanitits is similar to the treatment of periodontitis and it consists of mechanical cleaning of the biofilm from the implant surface. This is of the utmost importance when treating peri-implanitits. During resective treatment, plastic curettes, air-powder abrasive or ablative lasers and ultrasonic scalers are used [52]. The main objective is to clean the surface which can stop the progression of the disease and increase the chances for re-osseointegration of the implant. However, due to the implant surface roughness, the bacterial adhesion and colonization is very difficult to remove and sometimes mechanical debridement alone is not very effective [53]. It has been suggested by some authors that the mechanical elimination of the implant threads and then smoothing the implant surface (implantoplasty) should be done, in order to improve the decontamination of the implant surface. In addition this procedure allows better maintenance and oral hygiene when threads are exposed to the oral environment [54]. When decontaminating the implant surface, the use of metallic curettes is not recommended due to the fact that they can alter the surface roughness of the implant and favor bacterial colonization. As an alternative, plastic curettes should be used because they do very little damage or none at all [55, 56].

Recently, as a treatment alternative, many scientists have shifted their focus towards the laser decontamination of the implant surfaces. In a study done by Kreisler et al. [57] the mechanical effects of Nd:YAG (Neodymium: yttrium-aluminum-garnet), Ho:YAG (Holmium: yttrium-aluminum-garnet), Er:YAG (Erbium: yttrium-aluminum-garnet), CO2 (Carbon dioxide) and GaAlAs (Gallium-Aluminum-Arsenide) lasers were evaluated, on different types of implant surfaces.. According to their results, Nd:YAG and Ho:YAG lasers cause significant damage to the implant surfaces, while CO2 and Er:YAG lasers when used in specific power settings do not cause any damage. GaAlAs laser did not damage the implant surface in any power settings. As an adjunct therapy to mechanical methods for treating peri-implantitis, the use of chemical decontamination and antibiotic therapy are being used with the aim of improving the treatment outcome. The most commonly used antimicrobial solutions are chlorhexidine, hydrogen peroxide, tetracycline or minocycline, citric acid, and phosphoric acid [58].

Recently aPDT has emerged as a new treatment option or adjuvant treatment to the conventional treatment of peri-implantitis. Its potential to decontaminate the implant surfaces without any damage to the implant or the surrounding tissues has generated a lot of interest in the scientific community. In addition aPDT is more effective than the use of lasers alone [53]. In their study, Hayek et al. [59] demonstrated that aPDT is both effective and non-invasive method when compared to traditional therapy during surgical treatment of peri-implantitis with elevated mucoperiosteal mucosal flaps. These beneficial characteristics of aPDT make it as promising novel and non-invasive method which can be used alone or as an adjunct therapy of peri-implantitis [2].

### **2. The efficacy of photodynamic therapy in** *in vitro* **conditions**

There are many *in vitro* studies evaluating the efficacy of photodynamic therapy against causative bacteria of peri-implantitis. The aim of our research was to evaluate the efficacy of aPDT on titanium and zirconia dental implants. For this purpose three different devices in combination with photosensitive dye were used.

**153**

**Figure 1.**

*the bacterial suspension.*

*Evaluation of the Antimicrobial Efficacy of Different Types of Photodynamic Therapy…*

In addition, our aim was to evaluate if aPDT causes damage and alteration to the implant surfaces which would interfere with the re-osseoinegration of the implants

The study sample consisted of 144 sterile dental implants (72 titanium dental implants and 72 zirconia dental implants) (Bredent®, Senden, Germany). Both, titanium and zirconia dental implants were with a diameter of 4.0 mm and 12 mm of length, with sandblasted and acid etched surface. Each of the implants was in an

A bacterial suspension was prepared from three bacteria species: *Prevotella intermedia, Aggregatibacter actinomycetemcomitans*, and *Porphyromonas gingivalis*.

The bacteria were cultivated separately in Columbia Agar for 72 hours and then, using thioglycolate broth, a bacterial suspension was prepared for each of the bacteria. The suspension of each of the bacteria was then mixed together in a joint

In a single use tubes 300 μl of the bacterial suspension was put and then each implant was put separately in single use tubes (**Figure 1**). The tubes were incubated

The implants were treated with a diode laser (Laser HF®, Hager Werken, Duisburg, Germany) and a toluidine blue-based dye (155 μg/ml, LaserHF® Paro-

A combination of a diode laser (Helbo® Therapielaser, Helbo Photodynamic Systems GmbH & Co KG, Grieskirchen, Austria) and a phenothiazine chloride dye (Helbo® Blue photosensitizer) was used for the treatment of the implants belong-

*Implants placed in Eppendorf tubes containing bacterial suspension. Implants covered in their entire length by* 

After the incubation period, the implants were taken out of anaerobic conditions and they were randomly divided into four study groups and two control groups,

*DOI: http://dx.doi.org/10.5772/intechopen.94268*

**2.1 Bacterial contamination of dental implants**

These bacteria are commonly found in peri-implant diseases.

PDT solution). The laser parameters are presented in **Table 1**.

ing to this group. The laser parameters are presented in **Table 2**.

in the clinical conditions.

unopened sterile packaging.

in anaerobic conditions for 72 hours.

**2.2 Group 1. LaserHF (PDT1)**

**2.3 Group 2. Helbo laser (PDT2)**

each group containing twelve implants (n = 12).

suspension.

*Evaluation of the Antimicrobial Efficacy of Different Types of Photodynamic Therapy… DOI: http://dx.doi.org/10.5772/intechopen.94268*

In addition, our aim was to evaluate if aPDT causes damage and alteration to the implant surfaces which would interfere with the re-osseoinegration of the implants in the clinical conditions.

The study sample consisted of 144 sterile dental implants (72 titanium dental implants and 72 zirconia dental implants) (Bredent®, Senden, Germany). Both, titanium and zirconia dental implants were with a diameter of 4.0 mm and 12 mm of length, with sandblasted and acid etched surface. Each of the implants was in an unopened sterile packaging.

### **2.1 Bacterial contamination of dental implants**

A bacterial suspension was prepared from three bacteria species: *Prevotella intermedia, Aggregatibacter actinomycetemcomitans*, and *Porphyromonas gingivalis*. These bacteria are commonly found in peri-implant diseases.

The bacteria were cultivated separately in Columbia Agar for 72 hours and then, using thioglycolate broth, a bacterial suspension was prepared for each of the bacteria. The suspension of each of the bacteria was then mixed together in a joint suspension.

In a single use tubes 300 μl of the bacterial suspension was put and then each implant was put separately in single use tubes (**Figure 1**). The tubes were incubated in anaerobic conditions for 72 hours.

After the incubation period, the implants were taken out of anaerobic conditions and they were randomly divided into four study groups and two control groups, each group containing twelve implants (n = 12).

#### **2.2 Group 1. LaserHF (PDT1)**

*Photodynamic Therapy - From Basic Science to Clinical Research*

The main goal of resective treatments is to eliminate the etiological factors of periimplanittis and maintain optimal conditions. These treatments are mainly done by cleaning and decontaminating implant surfaces. Regenerative treatments aim to reconstruct the pre-existing hard and soft tissues by using bone substitute grafts, membranes and growth factors [50, 51]. Resective treatment of peri-implanitits is similar to the treatment of periodontitis and it consists of mechanical cleaning of the biofilm from the implant surface. This is of the utmost importance when treating peri-implanitits. During resective treatment, plastic curettes, air-powder abrasive or ablative lasers and ultrasonic scalers are used [52]. The main objective is to clean the surface which can stop the progression of the disease and increase the chances for re-osseointegration of the implant. However, due to the implant surface roughness, the bacterial adhesion and colonization is very difficult to remove and sometimes mechanical debridement alone is not very effective [53]. It has been suggested by some authors that the mechanical elimination of the implant threads and then smoothing the implant surface (implantoplasty) should be done, in order to improve the decontamination of the implant surface. In addition this procedure allows better maintenance and oral hygiene when threads are exposed to the oral environment [54]. When decontaminating the implant surface, the use of metallic curettes is not recommended due to the fact that they can alter the surface roughness of the implant and favor bacterial colonization. As an alternative, plastic curettes should be used because they do very little damage or none at all [55, 56]. Recently, as a treatment alternative, many scientists have shifted their focus towards the laser decontamination of the implant surfaces. In a study done by Kreisler et al. [57] the mechanical effects of Nd:YAG (Neodymium: yttrium-aluminum-garnet), Ho:YAG (Holmium: yttrium-aluminum-garnet), Er:YAG (Erbium: yttrium-aluminum-garnet), CO2 (Carbon dioxide) and GaAlAs (Gallium-

Aluminum-Arsenide) lasers were evaluated, on different types of implant surfaces.. According to their results, Nd:YAG and Ho:YAG lasers cause significant damage to the implant surfaces, while CO2 and Er:YAG lasers when used in specific power settings do not cause any damage. GaAlAs laser did not damage the implant surface in any power settings. As an adjunct therapy to mechanical methods for treating peri-implantitis, the use of chemical decontamination and antibiotic therapy are being used with the aim of improving the treatment outcome. The most commonly used antimicrobial solutions are chlorhexidine, hydrogen peroxide, tetracycline or

Recently aPDT has emerged as a new treatment option or adjuvant treatment to the conventional treatment of peri-implantitis. Its potential to decontaminate the implant surfaces without any damage to the implant or the surrounding tissues has generated a lot of interest in the scientific community. In addition aPDT is more effective than the use of lasers alone [53]. In their study, Hayek et al. [59] demonstrated that aPDT is both effective and non-invasive method when compared to traditional therapy during surgical treatment of peri-implantitis with elevated mucoperiosteal mucosal flaps. These beneficial characteristics of aPDT make it as promising novel and non-invasive method which can be used alone or as an adjunct

**2. The efficacy of photodynamic therapy in** *in vitro* **conditions**

against causative bacteria of peri-implantitis. The aim of our research was to evaluate the efficacy of aPDT on titanium and zirconia dental implants. For this purpose three different devices in combination with photosensitive dye were used.

There are many *in vitro* studies evaluating the efficacy of photodynamic therapy

minocycline, citric acid, and phosphoric acid [58].

therapy of peri-implantitis [2].

**152**

The implants were treated with a diode laser (Laser HF®, Hager Werken, Duisburg, Germany) and a toluidine blue-based dye (155 μg/ml, LaserHF® Paro-PDT solution). The laser parameters are presented in **Table 1**.

#### **2.3 Group 2. Helbo laser (PDT2)**

A combination of a diode laser (Helbo® Therapielaser, Helbo Photodynamic Systems GmbH & Co KG, Grieskirchen, Austria) and a phenothiazine chloride dye (Helbo® Blue photosensitizer) was used for the treatment of the implants belonging to this group. The laser parameters are presented in **Table 2**.

#### **Figure 1.**

*Implants placed in Eppendorf tubes containing bacterial suspension. Implants covered in their entire length by the bacterial suspension.*


*PDT1 treatment parameters.*


**Table 2.** *PDT2 treatment parameters.*

#### **2.4 Group 3. Light-emitting diode treatment group (PDT3)**

The implants belonging to this group, were treated with LED curing light (Optilight Ld®, Gnatus, Brazil). A red LED light, (Ledengin,Inc.®, San Jose, USA) was used in combination with a toluidine blue solution (Biognost®, Zagreb, Croatia). The laser parameters are presented in **Table 3**.

#### **2.5 PDT1, PDT2 and PDT3 decontamination steps**

The first step was coating the implants with the respective photosensitive dye according to the treatment group. After 60 seconds the implants were rinsed with sterile saline solution. For standardization of the treatment protocols for every treatment group, the implants, were placed in a rotating electric motor (Shenzhen Powerful Electronics, Shajing, China), with a rotating speed of 10 rpm.

The treatment time was 60 seconds for every group from a distance of 5 mm from the implant. The treatment procedures for titanium and zirconia implants are shown in **Figures 2** and **3**.

#### **2.6 Group 4. Treatment with toluidine blue only (TB)**

The implants belonging to this group were placed in photosensitive dye (toluidine blue; Biognost®, Zagreb, Croatia) solution (1 mg/ml) for 60 seconds. Then they were rinsed with sterile saline solution.

#### **2.7 Control groups**

Two control groups were included. The negative control group (NC) did not receive any treatment. After removing the implants from the bacterial suspension and keeping them in room conditions for 60 seconds, microbiologycal analysis followed.

**155**

**Figure 3.**

*Evaluation of the Antimicrobial Efficacy of Different Types of Photodynamic Therapy…*

*A titanium implant treated from a distance of 5 mm for 60 seconds while rotating on the electric motor.*

*A zirconia dental implant placed in a rotational motor and treated with PDT2 for 60 seconds.*

*DOI: http://dx.doi.org/10.5772/intechopen.94268*

Fiber tip: 6 mm LED composite curing tip

Wavelength: 660 nm

Power output: 200 mW Power density: 0.71 W/cm2 Irradiation Time: 60 seconds Distance from the implant: 5 mm

*PDT3 treatment parameters.*

**Table 3.**

**Figure 2.**

*Evaluation of the Antimicrobial Efficacy of Different Types of Photodynamic Therapy… DOI: http://dx.doi.org/10.5772/intechopen.94268*


**Table 3.** *PDT3 treatment parameters.*

*Photodynamic Therapy - From Basic Science to Clinical Research*

**2.4 Group 3. Light-emitting diode treatment group (PDT3)**

Croatia). The laser parameters are presented in **Table 3**.

**2.6 Group 4. Treatment with toluidine blue only (TB)**

they were rinsed with sterile saline solution.

**2.5 PDT1, PDT2 and PDT3 decontamination steps**

The implants belonging to this group, were treated with LED curing light (Optilight Ld®, Gnatus, Brazil). A red LED light, (Ledengin,Inc.®, San Jose, USA) was used in combination with a toluidine blue solution (Biognost®, Zagreb,

The first step was coating the implants with the respective photosensitive dye according to the treatment group. After 60 seconds the implants were rinsed with sterile saline solution. For standardization of the treatment protocols for every treatment group, the implants, were placed in a rotating electric motor (Shenzhen

The treatment time was 60 seconds for every group from a distance of 5 mm from the implant. The treatment procedures for titanium and zirconia implants are

The implants belonging to this group were placed in photosensitive dye (toluidine blue; Biognost®, Zagreb, Croatia) solution (1 mg/ml) for 60 seconds. Then

Two control groups were included. The negative control group (NC) did not receive any treatment. After removing the implants from the bacterial suspension and keeping them in room conditions for 60 seconds, microbiologycal analysis followed.

Powerful Electronics, Shajing, China), with a rotating speed of 10 rpm.

Wavelength: 660 nm Fiber tip: 3D pocket probe Power output: 100 mW Power density: 35.37 W/cm2 Irradiation Time: 60 seconds Distance from the implant: 5 mm

*PDT1 treatment parameters.*

Wavelength: 660 nm

Power output: 100 mW Power density: 124.3 W/cm2 Irradiation Time: 60 seconds Distance from the implant: 5 mm

Fiber tip: 320 μm optical fiber tip

*PDT2 treatment parameters.*

shown in **Figures 2** and **3**.

**2.7 Control groups**

**Table 2.**

**Table 1.**

**154**

#### **Figure 2.**

*A titanium implant treated from a distance of 5 mm for 60 seconds while rotating on the electric motor.*

The implants belonging to the positive control group (PC) were put in 0.2% chlorhexidine gluconate solution (Curasept ADS® Curaden International AG, Kriens, Switzerland) for a duration of 60 seconds. After their removal from the chlorhexidine solution, the implants were only rinsed with sterile saline to remove the remaining solution.
