Indirect hybrid nano-ceramic adhesive restorations in the posterior region

In a mixed analogue-digital workflow, Dr Pierre Dimitrov, Dr Assen Marinov and MDT Boyanka Vladimirova demonstrate how they utilised Cerasmart270 to aesthetically restore three posterior teeth in the lower quadrant, without compromising on longevity.

Indirect composite and ceramic restorations are a valid solution in restoring medium to heavily damaged teeth in the posterior region, providing strength, longevity and aesthetics. With the advancement of CAD/CAM technologies and intraoral scanners we can produce and deliver these kinds of restorations in one visit or a few days, minimising the chance of sensitivity, maintaining tooth vitality and protecting the damaged tooth structures from cracks and fractures.

Using contemporary adhesive systems and composite materials, we are able to bond indirect restorations with little to no retention in the preparation, without unnecessary sacrifice of tooth structures and still be able to guarantee a predictable long-term success to our patients.

In the following case, we used mixed analogue-digital workflow to restore three posterior teeth in a quadrant where Cerasmart270 blocks (Fig. 1) in two translucencies were used – A3 HT for the molars and A3 LT for the endodontically treated, darker shaded premolar. The treatment was completed in two visits in the span of three days.

Initial situation

The patient initially presented with a few direct restorations in the left lower jaw (third quadrant) (Fig. 2). Complaints of the patient were increased sensitivity to thermal stimuli in this region and food impaction.

The second premolar was endodontically treated without radiologic or symptomatic signs of apical periodontitis, the buccal and lingual walls and the mesial marginal ridge were thin and undermined, and the shade of the tooth was visibly different.

The first molar was vital with a big direct composite restoration of the mesial, occlusal and distal surfaces with residual caries on the distal. The buccal and lingual wall were thin and suspected to crack or fracture at any time. The second molar was vital with a faulty direct restoration, showing degradation of the bond between restorative material and tooth, uncovered dentin, suboptimal proximal contacts and thin buccal and lingual walls.

The soft tissues were inflamed. The decided treatment plan with consent of the patient was to restore the second premolar and two molars with full coverage Cerasmart270 overlays in two visits – one for preparation and impressions and another one for bonding the restorations.

Treatment procedure

After isolation with rubber dam, the old restorations and underlying caries were removed with a round diamond bur on high speed with plenty of water cooling, followed by final cleaning of the decayed dentin with a steel manual excavator and gentle sandblasting with 27micron aluminium oxide particles.

A small portion of the mesiolingual pulp horn was exposed. The undermined and unsupported cusps and walls were reduced to ensure stable dentinal support of the tooth structures and provide restorative material space of 1.5-2mm. A buccal chamfer preparation was chosen for the second premolar out of aesthetic considerations (Figs. 3a-b).

An immediate dentin sealing procedure was carried out to ensure optimal adhesion to the freshly prepared dentin and to create a hermetically sealed biological system, protecting the tooth structures from contamination. A deep margin elevation was performed for the distal margin of the second premolar. Enamel margins were left uncovered to be available as an adhesion substrate in the cementation step. The pulp exposure was only sealed using adhesive and flowable composite.

The tooth structures were gently sandblasted for 10-15 seconds with 27micron aluminium oxide particles under pressure with plenty of water cooling. Dentin was then etched with 37% phosphoric acid for 15 seconds and generously rinsed afterwards, followed by gentle drying of the dentinal structure with a three-in-one syringe to prevent desiccation of the tooth structures.

Continue reading here. Published in Dental Asia September/October 2022 issue.

About the authors

Dr Pierre Dimitrov graduated from the Medical University of Sofia (Bulgaria), Faculty of Dental Medicine in 2016. He is working in the dental clinic DentaConsult in Sofia. His interests are in restorative dentistry of posterior teeth, endodontics, digital dentistry and dental technology. He has attended postgraduate courses in the fields of composite restorations, indirect ceramic restorations, endodontic treatment and digital workflow in restorative dentistry.
Dr Assen Marinov graduated from the Medical University of Sofia (Bulgaria), Faculty of Dental Medicine. He is practicing in the fields of dental implantology, functional and aesthetic dentistry. Dr Marinov has finished the basic curriculum at the Vienna Interdisciplinary School of Dentistry (VieSID) (Austria), implementing the protocol of Prof Rudolf Slavicek in his practice. He also finished the complete course in functional diagnostic wax-up of DTG Stephan Provancher and attended the Master Programme in digital and aesthetic dentistry with Paulo Kano. Together with the team of DentaConsult, Dr Marinov is developing a growing practice in Sofia. He is combining digital and analogue workflow in treatment planning and execution.
MDT Boyanka Vladimirova became a dental technician in 1994. She got her training and Dental Council’s registration at the Medical Collage in Varna (Bulgaria). She is a member of the Dental Technologists Association (DTA). She has been working at various laboratories and owns her own company since the beginning of 2018. She is also a ceramist at the team of DentaConsult. Her focus is on aesthetic crowns and bridges, with a strong attention to design, detail and quality.