Chairside

Minimally invasive cusp coverage: a cost-conscious, yet aesthetically pleasing approach

Clinical case by Jotautas Kaktys

An endodontically treated, structurally compromised mandibular molar with recurrent failure of direct composite restorations presents both biomechanical and aesthetic challenges. In patients with parafunctional habits such as bruxism, excessive tensile forces further increase the risk of fracture. This case report describes a minimally invasive, cost-conscious approach using a CAD/CAM hybrid material (KATANA™ AVENCIA™ Block 2, Kuraray Noritake Dental Inc.) to restore function, strength, and aesthetics while preserving remaining tooth structure.

CASE EXAMPLE: INITIAL SITUATION

The patient presented with a structurally compromised mandibular first molar and reported repeated failure of composite restorations, as well as dissatisfaction with aesthetics (Figs. 1 to 3). Longevity, strength, and cost-effectiveness of the treatment were key concerns.

Clinical findings, including worn canines and multiple cervical lesions, indicated a bruxing patient with group guidance during lateral movements, leading to excessive tensile stress and increased fracture risk. An indirect restoration with cusp coverage was indicated. Due to financial limitations and uncertain endodontic prognosis, a CAD/CAM hybrid material KATANA AVENCIA Block 2 ML (Kuraray Noritake Dental Inc.) in the shade A3 (Fig. 4) was selected.

Fig. 1. Initial situation: Buccal view of the mandibular first molar in need of treatment due to a cervical lesion and a leaking composite restoration.

Fig. 2. Buccal view of the teeth in occlusion.

Fig. 3. Occlusal view of the tooth revealing a number of defects.

Fig. 4. Shade selection: Image taken with the A3 tab of the VITA classical A1-D4 shade guide for communication with the dental technician.

TOOTH PREPARATION AND IMMEDIATE DENTIN SEALING

Preparation was kept minimally invasive to preserve remaining tooth structure while creating space for adequate material thickness (~1.5 mm; Figs. 5 and 6). Weak cusps were reduced with minimal biological sacrifice.

After sandblasting and pre-treatment of the old composite and fiber post surfaces with silane, exposed dentin was sealed using CLEARFIL™ SE Protect and coated with CLEARFIL MAJESTY™ ES Flow (Low flowability, shade A3D; both Kuraray Noritake Dental Inc.; Figs. 7 and 8). Due to the presence of sclerotic dentin, we decided to reactivate the surface and use a two-step self-etch system instead of a universal adhesive. Resin coating was performed to protect the underlying tooth structure and mask discolouration.

Fig. 5. Tooth preparation preserving the remaining enamel and the cervical tissues.

Fig. 6. Adequate occlusal clearance.

Fig. 7. Immediate dentin sealing and resin coating.

Fig. 8. Tooth ready for intraoral scanning.

DIGITAL WORKFLOW

The intraoral situation was digitised using an intraoral scanner (Figs. 9 to 11). This enabled efficient computer-aided design and manufacturing (exocad DentalCAD; Figs. 12 to 14). The occlusal design was adjusted to minimise tensile forces during lateral movements. The restoration was milled and required only minimal finishing and polishing (TWIST™ DIA for Composite, Kuraray Noritake Dental Inc.), which was quick and effective (Fig. 15).

Fig. 9. Digital model of maxilla and mandible revealing sufficient space for the planned restoration.

Fig. 10. Preparation margins clearly visible both in the coloured …

Fig. 11. … and the black-and-white modes of the software.

Fig. 12. Computer-aided design in the laboratory using exocad DentalCAD.

Fig. 13. Milled restoration with milling sprue positioned at the buccal wall – an area which is easily adjustable (no interproximal or occlusal contacts affected) and stable.

Fig. 14. Milled restoration with smooth margins (no irregularities) due to non-brittleness of the hybrid ceramic material.

Fig. 15. Polishing is accomplished in two to three minutes and leads to great results.

TRY-IN AND PLACEMENT

Tissues had healed nicely in the three weeks between impression taking and final restoration placement (Fig. 16). Try-in confirmed a perfect fit of the restoration. Optical integration was difficult to assess without try-in paste (Fig. 17), but the patient was happy anyway, so that it was decided to move on immediately.

Isolation was achieved using a retraction cord (size 00) and PTFE tape (Fig. 18). As the bonding substrate consisted mainly of enamel and composite, a universal adhesive CLEARFIL™ Universal Bond Quick was selected. It was applied after phosphoric acid etching and treated with a gentle stream of air until the adhesive layer was uniformly thin (no pooling) and the surface did no longer move. As some remaining exposed dentin was present, the adhesive was polymerised to stabilize the hybrid layer. The restoration was pretreated (sandblasting, cleaning, CLEARFIL™ CERAMIC PRIMER PLUS) and adhesively cemented using a light-curing resin cement system to provide for dependable bonding.

Fig. 16. Healthy tissues at the delivery visit.

Fig. 17. Try-in of the restoration to assess the fit – no adjustments were necessary.

Fig. 18. Soft tissue management and moisture control with a retraction cord and PTFE tape, surface sandblasted to prepare for adhesive cementation.

TREATMENT OUTCOME

While the soft tissues were still slightly retracted after treatment and the optical integration difficult to assess due to dehydrated tooth structure (Fig. 19), radiographic examination confirmed proper biological integration (Fig. 20) and the patient was satisfied immediately. When she returned for a check-up after six months, we saw healthy soft tissues, a great marginal seal and proper aesthetic integration (Fig. 21). The restoration margins blended in nicely, no signs of wear were detectable and polish retention was great (Fig. 22).

Fig. 19. Immediate treatment outcome.

Fig. 20. Final radiograph.

Fig. 21. Restoration at a recall after six months. The gingiva appears healthy and has grown over the restoration margin, which is a sign of the material's biocompatibility.

Fig. 22. Smooth occlusal surface without any signs of wear.

CONCLUSION

Minimally invasive cusp coverage with KATANA AVENCIA Block 2 offers a predictable and cost-effective solution for structurally compromised posterior teeth. This is because the production procedure involves fewer manual steps, such as characterisation and glazing, while completely eliminating the need for heat treatment. A high level of automation further supports this efficiency. Successful outcomes depend on preserving the remaining tooth structure, careful treatment planning, and adherence to the recommended adhesive protocols.

Special thanks to dental technician Tautvilas Kaktys (my twin brother) and the dental laboratory RiCreo for their outstanding laboratory support and craftsmanship.

Dentist:

Jotautas Kaktys

Dr Jotautas Kaktys is a passionate Lithuanian restorative dentist and clinician, deeply dedicated to dental science. Known as a true "dental geek," he strives to understand every process down to the molecular level and perform every step of restorative procedures meticulously. At the high-end &SMILE clinic in Kaunas, he specializes in functional and minimally invasive biomimetic dentistry, handling everything from single restorations to complex full-mouth rehabilitations. His expertise extends across both analog and digital workflows, including TMD treatment. Since 2016, Jotautas has shared his knowledge globally, delivering 35+ courses and lectures. As a Key Opinion Leader for multiple dental brands, he provides valuable insights into adhesive techniques and restorative materials. He is also the co-founder of SOFTFORDENT, an IT venture focused on enhancing dental practice management. In collaboration with his twin brother, Tautvilas Kaktys, a dental technician and eLAB instructor, Jotautas strives for perfection in functional and esthetic prosthodontics. A member of the European Prosthodontic Association and the Digital Dentistry Society, he remains committed to clinical excellence and the continuous pursuit of scientific knowledge.