Minimally invasive treatment strategies with Polymer- Infiltrated-Ceramic-Network (PICN) materials

Tooth wear (TW) is a multifactorial issue, making the understanding of its risk factors
essential for effective management. Despite its importance, a comprehensive review
that synthesizes findings to guide clinical decisions is lacking. Bruxism and TW may be
linked to various chronic diseases, but current data are limited, highlighting the need for
further research. Diagnosis and prevention of TW are crucial, but selecting appropriate
restorative treatments is equally important. Currently, there is no consensus on the
optimal technique or material for restoring severely worn dentition, particularly due to the
lack of long-term studies.
The One-Step No-Prep technique is a non-invasive restorative approach for generalized
TW, using Polymer-Infiltrated Ceramic Network (PICN or hybrid ceramic, Vita Enamic)
CAD-CAM restorations. Introduced in 2018, the technique has shown successful
preliminary results, but its long-term effectiveness needs to be validated through
extensive research. PICN materials seem well-suited for this technique, but their clinical
performance, especially long-term, is not well-studied, particularly regarding wear
resistance—an important factor for bruxism patients.
The primary aim of this thesis was to contribute to the assessment of the One-Step
No-Prep technique. Additionally, this study sought to advance TW diagnosis and to
investigate the intraoral wear of PICN materials.
The first work package (WP) introduced the ToWeR checklist, a tool to enhance the
understanding of TW risk factors in clinical practice. The second WP explored the
association between bruxism, TW, and MSDs, emphasizing the need for a holistic
approach. The third part of this work presents a critical review of the evolution of indirect
composites to better understand their properties and the contributions of new materials
to improved treatment strategies. Subsequent WPs focused on evaluating the One-Step
No-Prep technique in a prospective clinical context. The fourth WP investigated the
clinical performance of PICN restorations and their impact on patients’ oral health-related
quality of life over a two-year period in seven patients.
The fifth WP evaluated the intraoral wear of PICN CAD-CAM composite restorations over
five years using ex vivo 3D profilometry analyses. The sixth WP reported up to nine years
of follow-up in 24 patients and assessed the influence of restoration thickness on
fracture rates. PICN was confirmed as well-suited to the One-Step No-Prep protocol due to its thin milling
capability, adaptability during in-mouth adjustments, and ease of repair, especially in
bruxers. The material’s polymer component aids in occlusal stress absorption. At nine
years, the survival rate was 98.4%, with a success rate of 79.7%, rising to 86.7% when excluding minor chipping. The thesis demonstrated that maintaining a restoration
thickness of 0.56 mm could reduce minor chipping. After five years, PICN restorations
exhibited wear values slightly lower than natural enamel, without significant abrasive
effects, maintaining occlusal stability. PICN offers a balanced option between the
excessive abrasiveness of glass-ceramics and the high wear of direct composites. The
esthetic properties of PICN, particularly with Vita Enamic multiColor blocks, were rated
as excellent or good over time, outperforming direct composites in resistance to staining
and discoloration.
The One-Step No-Prep protocol was shown to combine the benefits of direct techniquesminimally
invasive, easy repair—with those of indirect techniques, such as access to
superior materials and efficient restoration anatomy creation. This work highlights the
successful longterm outcomes of the One-Step No-Prep technique and exhibits the
clinical performance of PICN material, an appropriate material for this non-invasive
treatment of TW.