Photodynamic therapy involves interactions between a light source and a photosensitizer in an aerobic environment. This results in the generation of free oxygen radicals that damage target cells such as bacterial cells. Photodynamic therapy has also been reported to kill pathogenic microbes associated with the etiology of periodontal and peri-implant disease such as Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Prevotella intermedia, and Porphyromonas gingivalis (P. gingivalis). MD with adjunct photodynamic therapy is more effective in reducing peri-implant PPD than MD alone at 3 months following treatment (Fig. 2). However, in the long-term outcomes of MD either with or without photodynamic therapy are comparable.
Adjunct use of diode laser did not yield any additional positive influence on the peri-implant healing compared with MD alone at 3 months or 6 months following treatment[14, 45]. Two included RCTs were about the effect of Er:YAG laser (ERL) as an adjunct in the treatment of peri-implant diseases. Studies have indicated that nonsurgical periodontal treatment with an ERL significantly improve clinical outcomes as evidenced by PPD reduction and gain of CAL[46, 47]. The sites treated with ERL demonstrated a mean CAL change from 5.8 ± 1 mm at baseline to 5.1 ± 1.1 mm after 6 months. Frank et al. found that ERL could also reduce BOP significantly at 6 months following treatment. Further studies are needed to compare the effectiveness of ERL modality to that of other adjunctive therapies.
A total of two included RCTs were about the effect of air abrasive as an adjunct in the treatment of peri-implant diseases[10, 11]. Both found that adjunctive air abrasive treatment seemed to have a limited beneficial effect as compared with MD alone. Air abrasive devices have been shown to be a feasible treatment option in periodontal care because it has the potential to effectively erase biofilms. However, professional MD can effectively remove biofilms where the instruments can reach, thus the adjunctive effect of air abrasive may be limited.
Chlorhexidine is a commonly used topical drug. As shown in Fig. 3, compared with MD alone, MD with chlorhexidine have a limited beneficial effect at 3 months following treatment. An included article reported the adjunctive effect of chloramine and found that chloramine could not improve the clinical outcomes of peri-implant diseases. The effects of probiotic Lactobacillus reuteri in combination with MD were evaluated in implants with peri-implantitis, and no clinical differences between probiotic and placebo treatments were observed over time[35, 36] (Fig. 4). On the contrary, minocycline microspheres as an adjunct to MD treatment of incipient peri-implantitis lesions demonstrated improvements in PPD and BI that were sustained over 6 months[28, 29]. The state of the topical drugs, the concentrations of the topical drugs and the way of delivering topical drugs may affect the effectiveness of the drugs. Dental water jet rinse mixed with chlorhexidine gel might supplement the response to nonsurgical treatment for peri-implantitis lesions by reducing PPD. Studies have found that repeated chlorhexidine chips application might resolve marginal peri-implant inflammation in terms of BOP better than chlorhexidine gel, and PPD was more reduced with 0.65 ± 0.40 mm [30, 38]. The efficacy of a single dose is limited, repeated application of local drugs can prolong the effectiveness. However, the frequent use of antibiotics causes bacterial resistance in the subgingival biofilm. There is no consensus on how to deliver topical drugs in the treatment of peri-implant diseases. Therefore, further studies are warranted.
Standardized mean difference of clinical outcomes (BOP, PPD) between group MD with systemic antibiotics treatment and group MD alone was found no significant difference from 0 (P = 0.47) (Fig. 5). So far, the studies have not provided evidence for the use of systemic antibiotics in treatment of peri-implantitis[33, 34].
Tapia et al. found that modifying the contour of the prostheses after mechanical debridement significantly improved the clinical outcomes of peri-implant mucositis. This conclusion was correlated to the inclusion criteria of the study, which required the included patients to have at least one implant supported restoration with an inappropriate prosthesis design or contour that made difficult oral hygiene access to the neck of the implant. Implant supported prosthesis design is important to promote accessibility to oral hygiene around implants, which suggests a way to treat peri-implantitis.
Enamel matrix derivatives have been employed successfully in the management of periodontal diseases and in particular bone loss associated with periodontitis. Kashefimehr et al. studied the effects of enamel matrix derivative on non-surgical management of peri-implant mucositis, and they found that MD in conjunction with enamel matrix derivative, air abrasive and 0.12% chlorhexidine mouthwash significantly improved BOP and PPD at 3 months following the treatment. In the group with enamel matrix derivative, PPD reduced from 5.40 ± 1.79 mm to 4.66 ± 1.95 mm. More studies are required to prove the efficacy of enamel matrix derivative in longer-terms.
After comparing different adjunctive therapies, we found that the use of ERL or repeated minocycline microspheres as an adjunct to MD treatment for peri-implantitis is better than chlorhexidine gel[12, 28]. Adjunct use of photodynamic therapy was as effective as one unit-dosage of minocycline microspheres or diode laser after 6 months of follow-up[15, 21, 22]. The efficacy of probiotics as an adjunct to the MD treatment was better than that of systemic antibiotics in reducing PPD and mBI. Further studies are needed to compare the effectiveness of different adjunctive therapies.