PDT 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. At present, the light sources of PDT are mainly included diode laser, argon laser, Er:YAG laser (ERL) and light emitting diode (LED)[12-14, 46, 47]. Studies have indicated that nonsurgical periodontal treatment with an PDT significantly improve clinical outcomes as evidenced by PPD reduction and gain of CAL[46, 48]. PDT 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). A total of 7 articles included in this study were about PDT, three of which were about peri-implant mucositis[14, 17, 19] and four were about peri-implantitis[13, 16, 20, 41]. The follow-up time of three literatures on peri-implant mucositis was only three months, probably because inflammation had improved significantly within three months after treatment, and no longer observation time was required. These three literatures all concluded that MD with PDT could significantly reduce clinical signs of inflammation like CAL and PPD compared with MD alone. For peri-implantitis, the short-term effect of MD adjunct PDT was significant, but the long-term effect was comparable to MD alone. As the meta-analysis shown in Fig.2. Compared with peri-implant mucositis, peri-implant inflammation can lead to defects of bone tissues around the implant and contamination of the implant surface, making treatment more difficult. All of the 7 studies applied PDT only once, and there is no research on whether repeated use of PDT will improve or prolong its effect on the treatment of peri-implantitis.
Air abrasive devices have been shown to be a feasible treatment option in periodontal care because it has the potential to effectively erase biofilms. Amino acid glycine particles had been proved to be effective in removal of the biofilm. One of the included RCTs was about the effect of air abrasive as an adjunct in the treatment of peri-implant diseases, which found that adjunctive air abrasive treatment seemed to have a limited beneficial effect as compared with MD alone. Professional MD can effectively remove biofilms where the instruments can reach, thus the adjunctive effect of air abrasive may be limited. The evidence available does not allow for any conclusive statements on the clinical application of air polishing for the management of peri-implant diseases.
Four articles included in this review were about the adjunct effect of chlorhexidine in the treatment of peri-implant diseases. 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). Compared with chlorhexidine, 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 in a short term 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.
Two articles included in this study were about systemic antibiotics, one was about peri-implant mucositis and the other was about periimplantitis. Both literatures found that systemic antibiotics had limited effect in the treatment of peri-implant diseases, as the 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). This may because the amount of systemic antibiotics that can reach the area around the implant is little, so the local antibacterial effect is not significant. Tada et al. evaluated the adjunctive clinical efficacy of systemic antibiotics in the treatment of peri-implantitis with MD and probiotic. They founded that the PPD was significantly lower in the test group. This suggests that we can combine multiple treatments when treating peri-implantitis, which may increase the clinical effect.
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.
In summary, our study compared several therapies as adjuncts to the non-surgical MD treatment of peri-implant lesions. Our results indicate that PDT is a promising adjunct method for the treatment of peri-implant mucositis. Modifying the prosthesis also has significant effects in the treatment of peri-implant mucositis. However, from the perspective of long-term efficacy, there is still no effective non-surgical treatment of peri-implantitis. The combination of multiple treatments for peri-implantitis may improve the clinical outcomes. Further studies are warranted.