The bacterial biofilm disrupts the host-microbe homeostasis, creating a dysbiosis which results in an inflammatory lesion. The inflammatory cell infiltrate has been found to increase in size as the peri-implant mucositis develops.Where peri-implant mucositis has been brought about by the accumulation of bacteria and their formation of a biofilm, it has been shown to be eventually reversible once the biofilm has been brought under control by regular cleaning by both patient and dental professional. This has been shown as studies display a clear reduction in redness, swelling and bleeding on probing in lesions of the peri-implant soft tissue after bacterial load has been minimised. This was shown in an experiment where bacteria were encouraged to accumulate for a period of time in which no oral hygiene was undertaken, allowing all of the patients to develop peri-implant mucositis. When oral hygiene was regularly commenced once again, all of the periodontal tissues eventually became healthy once more. However, the best management of peri-implant mucositis is not reversing it but preventing this from occurring in the first instance.The presence of excess luting cement has been demonstrated to contribute to causing peri-implant mucositis. One study gleaned results that suggested that in both patients with and without a history of periodontal problems, implants with extracoronal residual cement developed statistically significantly more cases of peri-implant mucositis as well as other periodontal problems. In this study 85% of implants in patients with previous periodontal conditions went on to develop peri-implant mucositis, which then progressed to peri-implantitis.
Soreness

Risk Factors
Risk Factors of PIM are categorised into General and Local Risk Factors
General Risk Factors

Smoking
Radiation Therapy
Poorly controlled Diabetes Mellitus (HbA1c >10.1)Local Risk Factors

Oral Hygiene
Poor compliance / access to regular supportive implant therapy
Design of Implant-supported prostheses affecting accessibility for plaque removal
Sub-mucosal restorations
Dimension of Keratinized Peri-implant mucosa
Excess CementPossible Risk Factors:
Some other possible risk factors may include the location the implant is placed, type of implant placed and the age of the subject, as it was found that these factors had significant influences on bleeding on probing (BOP).Although it is uncertain whether increased abutment roughness will cause an increase in plaque accumulation and hence increase the risk of peri-implant mucositis, a 12-month comparative analysis in humans found that “a further reduction of the surface roughness, below a certain "threshold R(a)" (0.2 microns), has no major impact on the supra‐ and subgingival microbial composition.”Implants and abutments made of zirconium dioxide (ZrO2) were claimed to be more bio-compatible compared to those made of titanium but clinical studies show that there were slightly higher BOP scores or no significant difference in BOP scores around ZrO2 compared to titanium abutments. Diagnosis
In order to diagnose peri-implant mucositis, it is essential to investigate probing parameters and complete a radiographic assessment. Correct diagnosis of peri-implant diseases is essential to allow appropriate management of the condition present.