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Corresponding author: Dr Wesley F. Vasques, College of Dentistry, Federal Fluminense University, Mario Santos Braga St, 28 - Centro, Niterói, RJ 24020-140, BRAZIL
A diastema between the maxillary central incisors affects an esthetic smile and has been treated in various ways. Precise diagnosis is essential to guide the choice of the most appropriate treatment. This clinical report describes closing a maxillary midline diastema with a computer-aided design and computer-aided manufacturing (CAD-CAM) composite resin.
The presence of space between one or more adjacent teeth is an obstacle to obtaining a proper smile,
The etiology of diastemas may include an atypical upper lip frenulum attachment, a discrepancy in the shape or size of teeth, agenesis of the lateral incisors, periodontal disease, and hereditary or ethnic characteristics.
; however, the material may not be color stable, and obtaining an emergence profile without creating a step close to the gingival margin is challenging.
Thus, the use of a computer-aided design and computer-aided manufacturing (CAD-CAM) composite resin is an excellent option, as it presents advantages when compared with direct restorations and even in relation to partial ceramic veneers.
The one step-no prep technique: a straightforward and minimally invasive approach for full-mouth rehabilitation of worn dentition using polymer-infiltrated ceramic network (PICN) CAD-CAM prostheses.
the properties of the CAD-CAM composite resins enable thin designs, with less possibility of chipping of the margins and less milling time than ceramics.
The one step-no prep technique: a straightforward and minimally invasive approach for full-mouth rehabilitation of worn dentition using polymer-infiltrated ceramic network (PICN) CAD-CAM prostheses.
This clinical report describes the replacement of composite resin direct restorations for maxillary midline diastema closure with indirect CAD-CAM composite resin restorations.
Clinical report
A 25-year-old woman, without significant medical history, attended a private dental office concerned about the esthetics of her smile and recurrent gingival inflammation (Fig. 1). The clinical examination showed aged restorations with rough surfaces and disharmony with the contour of the surrounding tissues, creating oral hygiene difficulties. She had an Angle Class I occlusion, absence of carious lesions, and good periodontal condition, except in the region of the maxillary midline papilla. The gingival margins of the maxillary lateral incisors were asymmetric as seen in Figure 1B.
The radiographs revealed a lack of symmetry of the mesiodistal widths of the maxillary central incisors, causing the diastema that had been restored with composite resin. After the advantages and disadvantages of different treatment options had been explained, she opted for composite resin CAD-CAM restorations.
Figure 1Patient dissatisfied with her smile esthetics. Aged restorations with rough surfaces and improper contour caused gingival inflammation. A, Smile view. B, Intraoral frontal view.
Maxillary and mandibular impressions were made with irreversible hydrocolloid (HydroPrint Premium; Coltène) and poured with Type IV dental stone (Fuji Rock; GC Corp) to make trays for at-home bleaching with 16% carbamide peroxide (Coltène) for 4 hours a day for 20 days.
A tungsten carbide bur (H283; Komet Dental) was used to remove the existing restorations, exposing a 3.0-mm midline diastema. The mesiobuccal line angles were slightly flattened with abrasive paper disks (SofLex; 3M 3Oral Care) to smooth the transition between the tooth and the definitive restoration (Fig. 2). A 2-step impression was made with polyvinyl siloxane (President The Original Putty Super Soft + President The Original Light Body; Coltène) by using the double cord technique (#000 + #1 Ultrapak; Ultradent Products, Inc), and solid definitive casts
The gingival design and emergence angles in the maxillary midline papilla were reshaped on the stone cast, and the indirect restorations were planned to optimize soft tissue contour.
The casts were scanned (TRIOS 4; 3Shape A/S), and the restorations were designed by using a software program (exocad dental CAD; exocad GmbH) (Fig. 3). After she had approved the restoration designs, they were milled from composite resin blocks (Brilliant Crios HT A1; Coltène) (Fig. 4).
Figure 2After removing previous restorations, mesiobuccal line angles flattened with abrasive disks (SofLex; 3M).
Before definitive adhesive luting, the intaglio surfaces of the partial veneers were airborne-particle abraded with aluminum oxide (25 to 50 μm at 0.15 MPa), followed by the application of a thin layer of universal adhesive (One Coat 7; Coltène) and left unpolymerized.
A dental dam was placed, and the enamel was airborne-particle abraded with aluminum oxide (25 to 50 μm at 0.15 MPa). The maxillary central incisors were conditioned with 37% phosphoric acid (Magic Acid; Coltène) for 30 seconds, washed with water, and dried with air jets. A thin layer of universal adhesive (One Coat 7; Coltène) was applied, the excess removed with a gentle air stream, and the adhesive left unpolymerized.
The luting agent, a microhybrid composite resin (Brilliant EverGlow BL Trans; Coltène), was preheated to 69 °C (CalsetTM; AdDent Inc). The veneers were also preheated, the luting agent placed, and the veneers seated with ultrasonic vibration (Pyon 2; W&H) and light polymerized for 20 seconds (Valo; Ultradent Products, Inc) as seen in Figure 5. Abrasive paper disks (SofLex; 3M) and a polishing system (Diacomp Plus; EVE, American Inc) were used to finish the restorations.
Figure 5Restorations bonded with dental dam isolation.
After removing the dental dam, the gingival margin of the maxillary right lateral incisor was repositioned through a flapless crown lengthening procedure.
The height of the alveolar bone crest was reduced through osteoplasty with a microchisel (Ochsenbein; Hu-Friedy) (Fig. 6).
Figure 6After flapless crown lengthening of right lateral maxillary incisor. Height of alveolar bone crest recontoured with microchisel (Ochsenbein; Hu-Friedy)
One week later, soft tissue healing and repositioning of the maxillary midline papilla was observed. The esthetics and contour of the restorations and the periodontium were satisfactory (Fig. 7).
Figure 7Healthy periodontal tissue after 7 days. A, Intraoral frontal view. B, Smile view.
The direct composite restorations had unsatisfactory contours, had worn, and were associated with an unaesthetic gingival contour and maxillary midline papilla. The stone casts allowed a modification of the gingival architecture so that indirect restorations could be designed for this revised architecture, achieving an improved emergence profile. The choice of CAD-CAM composite resin permitted veneers with minimal thickness, ensuring periodontal tissue health.
Acknowledgments
The authors thank MW Dental Studio CDT, Rio de Janeiro, Brazil for the definitive restorations.
The one step-no prep technique: a straightforward and minimally invasive approach for full-mouth rehabilitation of worn dentition using polymer-infiltrated ceramic network (PICN) CAD-CAM prostheses.
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