Laser treatment and disease characteristics of peri-implantitis

Abstract: Peri-implantitis is an inflammatory disease which affects the soft and hard tissues surrounding dental implants. Current theory is that peri-implantitis is a counterpart to periodontitis, which is the inflammatory disease that destroys the tooth’s supporting tissues. However, there are some key discrepancies and there is a need for more studies on the characteristics of peri-implantitis. If the disease is not stopped, there is a risk that the dental implant is lost. It has proven difficult to treat peri-implantitis with conventional nonsurgical or surgical treatments. This is also an area of peri-implantitis that needs further research. The overall aim was to evaluate laser treatment of peri-implantitis, as well as explore the patients’ experiences and disease characteristics. In study I, we tested the safety of using diode lasers on dental implants by evaluating two different wavelengths 445 nm and 970nm. The temperature increase in dental implants were tested in two different models, one being a PM. Rigorous amounts of cooling water and limiting the continuous irradiation time to a maximum of 15-20s seemed to be key factors, depending on the power setting. We also assessed potential surface alterations on titanium discs in SEM but did not see any. In study II, the patient’s experiences and sensations were explored qualitatively in semi-structured interviews. We confirmed previous findings of positive associations of dental implants and added some perspectives to them with some negative experiences. In this group of patients, already diagnosed with peri-implantitis, some reported feeling symptoms, which could mean that with education on early signs of inflammation, the patient can also monitor their peri-implant health. The experiences of laser treatment and mucosal flap surgery were that of slight discomfort and for both the localized anesthesia was described as the worst part. Those that received surgery mentioned the sutures as a main source of discomfort. This we confirmed quantitatively in study III, where the surgery patients rated their discomfort significantly higher during the first week of healing than those in the laser group. In study III, we could not establish equivalence in change of PPD and RBL between the laser treatment and mucosal flap surgery. Both treatments had similar numbers of unresponsive peri-implantitis lesions, but in the patients that improved in their PPD, the surgery had significantly higher pocket reduction. There was basically no difference in change of RBL, BOP, biomarkers, and bacteria between the treatments. In study IV, we found that the inflammatory profile and immune cell composition were similar between peri-implantitis and periodontitis. In homogenized soft tissue, peri-implantitis lesions had significantly higher levels of IL-1β, TNF-α, IL-4 IL-17A, IL-23, G-CSF, and BAFF, whereas periodontitis only had significantly higher levels of IL-1β, IL-4, and G-CSF, compared to non-disease controls. Although, peri-implantitis and periodontitis did not significantly differ, there was a tendency towards a stepwise increase in proportion of B cells, from lowest in controls to highest in peri-implantitis. The results in this thesis show the potential for 970 nm diode laser in treating peri-implantitis. With unique clinical data a suggested role for the treatment modality could be initial stages of peri-implantitis where extensive pocket elimination is not as needed. The findings also support the need for further studies in assessing the patients self-monitoring of peri-implant conditions as well as the potential difference in B cell proportion and activity between peri-implantitis and periodontitis.

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