Implant maintenance: the paradox between patient compliance and pathological prevalence

The longevity of dental implants relies on rigorous biofilm control and regular professional follow-up. However, the resistance of peri-implant tissues to inflammation is lower than that of natural teeth, exposing patients to major biological complications. While daily brushing is frequently reported by patients, the actual effectiveness of their maintenance techniques and their level of knowledge regarding infectious risks remain poorly documented variables, hindering the implementation of effective primary prevention strategies.

This cross-sectional study, conducted at the University of Michigan on 34 subjects (71 implants), was designed to identify modifiable gaps influencing the risk of peri-implant disease. The specific objective was to evaluate the associations between clinical diagnosis (health, mucositis, or peri-implantitis) and self-reported practices, sources of instruction received, as well as awareness of infectious and systemic risks. The authors sought to verify whether cleaning frequency, the interdental methods used, and the level of therapeutic education directly impact tissue status, thus testing the correlation between reported behaviors and the clinical reality observed at the chairside.

Methodology

This cross-sectional study was conducted within the University of Michigan clinics between February and July 2025. The sample included 34 adult patients (17 men and 17 women) with 71 restored implants.

The evaluation protocol combined direct clinical measurements and declarative data collection via a 13-item questionnaire:

• Clinical evaluation: For each implant, examiners measured probing depth (PD), bleeding on probing (BOP), plaque index (PI), facial and lingual keratinized mucosa width (KMW), as well as tissue phenotype (thin or thick). The peri-implant diagnosis was established according to pre-defined clinical criteria.
• Patient data: The survey assessed the frequency and duration of cleaning, the methods used (manual/electric brushes, floss, interdental brushes, irrigators), the level of confidence (Likert scale) and knowledge about infection risks or systemic links.
• Statistical analysis: Associations between behavioral variables and peri-implant health status were analyzed at the implant and patient levels via Chi-square tests and Fisher's exact tests (significance threshold p < 0.05).

Prevalence of peri-implant diseases and the hygiene paradox

The study, conducted on 34 patients (17 men, 17 women) totaling 71 implants, reveals a major discrepancy between patient self-assessment and clinical reality. Although 88.2% of subjects report daily cleaning, the prevalence of peri-implant diseases reaches 70.4% at the implant level.

Clinical and anatomical risk factors

Statistical analysis identifies several critical variables influencing tissue status:

• Retention mode: Cemented retention emerged as the most significant risk factor at the implant level (p = 0.011).
• Plaque index: A close correlation is confirmed between plaque accumulation and the presence of pathology (p < 0.001).
• History of periodontology: At the patient level, 100% of peri-implantitis cases had a history of periodontology (p = 0.029).
• Keratinized mucosa (KM): If the width of the buccal KM is not correlated with the diagnosis, the lingual KM shows a significant association between health and peri-implantitis (p = 0.01) as well as between mucositis and peri-implantitis (p = 0.04).
• Tissue phenotype: A non-significant trend (p = 0.172) suggests that thin tissues more frequently progress toward severe forms of the disease.

Behaviors and educational gaps

Cleaning frequency remains the strongest predictor of peri-implant health (p = 0.035). However, the study highlights major flaws in prophylactic maintenance strategies:

• Hygiene tools: Dental floss remains the most used tool (82.4%), while interdental brushes, although essential, are the least adopted (8.8%).
• Instruction deficit: Nearly a third of patients (32.4%) report having received no specific professional instructions for the maintenance of their implants.
• Overconfidence: The majority of patients report moderate to high confidence in their hygiene technique, with no correlation to their actual clinical health status (p = 0.22).

Finally, patients' level of theoretical knowledge regarding infection risks or systemic links showed no significant association with clinical status, suggesting that theoretical knowledge does not automatically translate into procedural effectiveness.

Clinical analysis: the gap between perception and reality

The most striking result of this study lies in the major disconnection between the patients' reported effort and their clinical health status. While 88.2% of subjects report daily cleaning and display moderate to high confidence in their technique, the prevalence of peri-implant pathologies reaches 70.4%. This discrepancy highlights that brushing frequency, despite being the strongest predictor of peri-implant health (p = 0.035), is not sufficient without real technical efficacy.

The identification of risk factors in the practice is crucial here: cemented restorations emerge as the most significant risk factor at the implant level (p = 0.011). At the systemic level, the study confirms a close link with the periodontal background, as 100% of patients with peri-implantitis had a history of periodontitis (p = 0.029). Notably: while the width of buccal keratinized mucosa showed no impact, the lingual width seems correlated with the severity of the pathology (p = 0.01).

Limits and perspectives

This cross-sectional study has inherent limitations due to its design: a small sample size (n=34) from convenience recruitment in a university setting, which limits the generalisability of the data. Furthermore, the self-reported nature of the questionnaire may induce social desirability bias regarding oral hygiene.

Implications for daily practice

The data reveal two immediate levers of action for the practitioner. On the one hand, nearly a third of patients report having received no specific professional instructions for their implants. On the other hand, the use of interdental brushes is marginal (8.8%), while dental floss remains the majority (82.4%) despite often lower efficacy on complex prosthetic profiles. Clinical effort must therefore focus on the systematic teaching of targeted techniques, prioritizing mechanical interproximal aids to transform patient goodwill into long-term clinical success.

In concrete terms, for the practitioner:

• Target interdental brushes: Only 8.8% of patients use them compared to 82.4% for dental floss; emphasize their superiority in disrupting the peri-implant biofilm.
• Secure restorations: Prioritize screw-retained over cement-retained prostheses, as the latter are statistically correlated with an increased prevalence of the disease in this cohort.
• Systematically re-educate: Nearly one-third of patients have received no professional instruction; never assume that hygiene techniques for natural teeth are acquired or applied for implants.
• Monitor history: A patient with a history of periodontology presents an increased risk of peri-implantitis, requiring a tighter professional maintenance protocol.

Technical lexicon of the study

Peri-implant mucositis: Inflammation of the mucosa surrounding the implant, induced by bacterial plaque, without loss of supporting bone. In this study, it represents the most frequent pathology (43 implants out of 71).

Peri-implantitis: Inflammatory state of the peri-implant tissues characterized by progressive crestal bone loss. The study reports that 100% of patients with peri-implantitis had a history of periodontology.

Keratinized Mucosa Width (KMW): Vertical dimension of the keratinized gingiva measured on the buccal and lingual surfaces. The authors identified a significant correlation between lingual KMW and the severity of peri-implant pathology.

Mucosal phenotype: Classification of soft tissue thickness (thin or thick) assessed by the visibility of the probe through transparency. A thin phenotype shows a non-significant trend toward more severe disease forms in this cohort.

Retention mode: Method of fixing the prosthetic restoration (cemented or screwed). Cemented retention is identified here as the most determining risk factor at the implant level for the development of a pathology.

Plaque Index (PI): Clinical measure of biofilm accumulation on the implant surface. It appeared to be significantly associated with disease status (p < 0.001), highlighting the gap between patient-reported brushing and actual effectiveness.

Primary prevention: Maintenance strategies aimed at preserving the health of an implant that has never shown clinical signs of disease. The study highlights that nearly one-third of patients received no professional instructions for this prevention.

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