Dr. Eleni Trikoili
BSc, MSc, PhD, CILT
• Senior Research Associate and Coordinator at the Laboratory for Dental Digital Technologies and Biomaterials, Department of Reconstructive and Gerodontology, Centre for Dental Medicine (ZMK), University of Bern, Switzerland.
• Her work, grounded in biomaterials science, concentrates on developing and characterising materials for restorative and preventive dentistry. Dr Trikoili collaborates with interdisciplinary teams to bridge materials science and clinical practice.
Burak Yilmaz, Selim Polat
introduction
introduction
Digital dentistry has undergone rapid developments and changed the contemporary approach to patient treatment in many ways. New chairside digital workflow protocols, for example, enable dental practitioners to simplify previously multistep laboratory procedures, reducing treatment time and lowering the cost of the process. Chairside protocols enable clinicians to perform restorations in a single office visit, providing patients with a more comfortable and efficient experience.
One factor contributing to this development is additive manufacturing, such as 3D printing. Initially, 3D printers were limited to prototyping because the available materials were of inadequate quality. However, recent technological advances have enabled their application in restorative dentistry, largely driven by significant improvements in both printing materials and printer capabilities. Contemporary 3D printing systems can now produce high-precision restorations with enhanced surface characteristics and satisfactory mechanical properties [1, 2, 3].
3D printing has become a transformative innovation in restorative dentistry, offering high precision, efficiency, and customization. In this context, 3D-printed composites represent one of the most promising material classes, providing clinicians with a viable alternative to CAD/CAM ceramic restorations and conventional direct composites. Recent developments in printable resin composites, particularly those reinforced with inorganic fillers, have further expanded the clinical indications for definitive restorations.
The aforementioned materials are relatively easy to fabricate, meet esthetic requirements, and can be readily adjusted intraorally. Although chairside applications are advancing rapidly and demonstrate considerable potential, further clinical studies are needed to strengthen the current evidence base. The literature on the routine clinical use of such applications remains limited, highlighting the importance of well-documented clinical case reports to support ongoing validation [3, 4, 5].
Surgical and Clinical Workflow
Surgical and Clinical Workflow
A 42-year-old female patient presented with an unusual clinical case involving a combination of restorative and rehabilitation challenges, primarily associated with a pre-existing condition of dysgnathia and a posterior crossbite. Her medical and dental history revealed that, during adolescence, she had undergone a bimaxillary surgical realignment osteotomy for the correction of a Class III malocclusion, which required hospitalization. Despite this orthognathic intervention, she subsequently developed extensive orthodontically induced root resorption affecting multiple teeth in both arches, ultimately compromising the integrity of her dentition (Fig. 1A–D, Fig. 2).
In addition, the patient developed periodontitis, which resulted in pronounced bone loss in the regions of teeth 16, 12, 22, and 26. Due to extensive bone loss and concerns raised by the patient about functional impairment and esthetics, a comprehensive treatment approach was planned. At the first surgical procedure, teeth 16, 12, 11, 21, 22, and 26 were removed because of the hopeless prognosis. In conjunction, an augmentation procedure was performed to maintain alveolar bone volume in regions 16 and 26 (Fig. 3).Immediately after this treatment, an interim removable partial denture with wire clasp retention was fabricated and inserted.
Reconstruction for the anterior maxillary defects (12–22) was performed after the initial treatment phase. Bone blocks harvested bilaterally from the posterior mandible were grafted to the anterior maxilla, thereby providing sufficient bone volume for prosthetically driven implant placement. During the same surgical intervention, bilateral mandibular osteosynthetic hardware was removed. Additionally, implants were placed in the posterior regions (16 and 26). A temporary Essix-type appliance (Fig. 4) was fabricated as a minimally invasive means of protecting the surgically treated areas.
“Bone blocks harvested bilaterally from the posterior mandible were grafted to the anterior maxilla.”
During the final reconstructive phase, previously placed osteosynthetic hardware was removed from the anterior maxilla to enable prosthetically driven implant placement. CBCT imaging was performed for implant planning (Fig. 5A, B), followed by guided implant surgery in the anterior region (11 and 21) using a static digital workflow to ensure precise three-dimensional positioning in accordance with the planned prosthetic outcome.
“CBCT imaging was performed for implant planning, followed by guided implant surgery in the anterior region using a static digital workflow to ensure precise 3D positioning.”
The definitive implant configuration comprised SLActive implants Standard Plus RN: 4.8 × 10 mm fixtures in regions 16 and 26, and TLC SLActive Standard Plus NT implants: 3.75 × 10 mm fixtures (Institute Straumann AG, Basel, Switzerland) in regions 11 and 21 (Fig. 6), achieving appropriate distribution across the arch and supporting a prosthetically optimized rehabilitation (Fig.7).
The restorative phase was executed within a fully digital workflow, tailored to the patient’s functional demands, esthetic expectations, and existing intra-oral conditions. Comprehensive intra- and extra-oral photographic documentation was integrated with a high-resolution digital impression (Fig. 8) captured using the Trios 5 intraoral scanner (3Shape, Copenhagen, Denmark).
The resulting datasets were consolidated into a unified digital patient record and transferred to the digital laboratory, where virtual treatment planning and prosthetically driven design were performed in a CAD environment.
Prosthetic and Laboratory Workflow
Prosthetic and Laboratory Workflow
The restorations were designed in TRIOS Design Studio (3Shape, Copenhagen, Denmark; Fig. 9A–C) and exported as STL files, then manufactured using a Dfab 3D-printing system (RD Printing, Thiene, Italy; Fig. 10). Within the integrated nesting software, the restorations were strategically oriented to ensure optimal surface accuracy, particularly along incisal and occlusal regions.
Printing was executed at a 50-micron layer thickness using a hybrid resin composite (Irix Max, Photoshade A1-A3.5), resulting in efficient fabrication times without technical complications.
TSLA technology
These materials were used to fabricate fixed prosthetic restorations with mechanical strength and aesthetic properties suitable for long-term intra-oral function. A recent chairside additive manufacturing approach, tilting stereolithography (TSLA; Dfab, RD Printing), was employed and had been increasingly investigated, including in implant-supported restorative workflows.
Compared with conventional vat-based polymerisation technologies, TSLA improved contamination control, handling, and environmental safety by eliminating open resin reservoirs and reducing exposure to volatile monomers. It also enabled rapid fabrication of monolithic restorations with high precision and minimal post-processing. Current in vitro and in vivo evidence supported its dimensional accuracy, marginal adaptation, and clinical applicability.
Photoshade color gradient technology enables the creation of highly realistic restoration shades by blending the two composite shades within the cartridge, according to the user-selected settings for each case. In this case, we selected a value of 9.5 mm at the cervical level and 5.5 mm at the Incisal level (Fig. 11).
“TSLA enables rapid fabrication of monolithic restorations with high precision and minimal post-processings.”
Prosthetic and Laboratory Workflow
Prosthetic and Laboratory Workflow
Post-processing was conducted per a standardized protocol. Printed restorations were cleaned in 96% ethanol, dried (Fig. 12), and detached from support structures before being post-polymerized in a dedicated curing unit (Dcure system).
Residual supports and minor irregularities were removed using fine tungsten carbide burs. Surface characterization was performed to enhance esthetic harmonization using the IPS Empress Direct system (Ivoclar AG, Schaan, Liechtenstein). The areas of interest were roughened with a fine-grit diamond bur and cleaned. Subsequently, they were coated with a thin layer of Adhese Universal to promote bonding and light-cured using the Bluephase PowerCure (Ivoclar AG, Schaan, Liechtenstein). Ochre, blue, and white composite shades were applied in thin layers, as required, and light-cured. The characterized areas were subsequently covered with IPS Empress Direct Effect Trans Opal and light-cured with a Bluephase PowerCure device.
This technique protects the characterization from direct surface exposure, resulting in improved long-term esthetic stability compared with conventional surface staining techniques.
Polishing was performed using OptraGloss Extra Oral (Ivoclar AG, Schaan, Liechtenstein), fine-grained points and wheels, cotton wheels, goat-hair brushes, and polishing paste.
Fit and the esthetic outcome (Fig. 13) were evaluated on printed models before the intra-oral try-in to ensure passive fit. The restorations were steam-cleaned before cementation. Subsequently, they were screw-retained and seated intra-orally (Fig. 14 and Fig. 15A, B).
Occlusion was assessed during static and dynamic movements, and minor adjustments were made to achieve balanced functional contacts within the established occlusal scheme. Oral hygiene access and cleansability were clinically verified and considered satisfactory.
CONCLUSION
CONCLUSION
The 3D-printed composite restorations demonstrated favorable clinical performance, providing a predictable solution for functional and esthetic rehabilitation (Fig. 16) in a case of severely compromised dentition. Their use was particularly advantageous in this patient, who required controlled occlusal loading and careful material selection due to reduced bone support and a history of extensive root resorption.
“The combination of the Irix Max gradient and IPS Empress Direct surface characterization resulted in a highly natural optical appearance.”
Discussion
Discussion
Clinically, a marked improvement in esthetics was achieved, with a significant enhancement of the smile line and correction of the crossbite relationship, resulting in a more harmonious overall facial and dental appearance. In the posterior region, a very slight occlusal contact was intentionally maintained on the implant-supported restoration to ensure controlled functional loading while preserving implant stability. The combination of the Irix Max gradient and IPS Empress Direct surface characterization resulted in a highly natural optical appearance, with enhanced depth, translucency, and surface gloss, contributing to a lifelike integration of the provisional restorations within the overall dentition. The patient reported high satisfaction with both the functional and esthetic outcome.
The complexity of the present case, involving extensive tooth loss following orthodontically induced root resorption, previous orthognathic surgery, and limited bone availability, required a prosthetically driven, digitally controlled treatment strategy, as conventional restorative pathways were considered less predictable for achieving both biomechanical control and esthetic integration under these conditions.
Within this context, a fully digital workflow combined with TSLA-based additive manufacturing was selected to enhance precision, streamline clinical steps, and ensure prosthetically guided execution throughout the restorative phase. The closed-cartridge TSLA system further contributed to procedural control by improving handling efficiency and reducing contamination risk in the clinical environment. Evidence on composite-based 3D-printed restorations supports their dimensional accuracy and clinical applicability, including in implant-supported scenarios. In this case, these advantages were directly translated into a predictable workflow from digital design to definitive prosthetic delivery.
Conclusion
Conclusion
This case highlights the clinical value of integrating TSLA-based 3D printing within a fully digital implant prosthodontic workflow for complex rehabilitative cases. The digital, prosthetically driven approach enabled predictable functional control and improved esthetic outcomes. TSLA-based additive manufacturing contributed to accurate fit, favorable biomechanics, and natural esthetic integration, supporting its potential role in implant-supported restorative rehabilitation.
The complexity of the present case, involving extensive tooth loss following orthodontically induced root resorption, previous orthognathic surgery, and limited bone availability, required a prosthetically driven, digitally controlled treatment strategy, as conventional restorative pathways were considered less predictable for achieving both biomechanical control and esthetic integration under these conditions.
Acknowledgements
Acknowledgements
The authors would like to thank Dr. S. Wiegner (Department of Cranio-Maxillofacial Surgery, University Hospital of Bern) for performing the surgical treatment. The surgical planning and overall therapy were performed in close consultation with the Department of Reconstructive Dentistry and Gerodontology.
The authors also express their gratitude to Mr. Alaa Abou Hasan (Qlab-Corus) for his valuable support in the design of the implant restorations.
References
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