reading

One of the areas in which technology has made a significant impact is photography— more precisely, computational photography, a new term that we all should be aware of. This concept is being driven by smartphone manufacturers, not by the traditional camera manufacturers. The convenience of a relatively small device with impressive computational abilities has prompted the development of novel features that are revolutionizing how we take or make photographs. The megapixel camera war continues, as newer smartphones have cameras up to 108MP. Even though some smartphones may produce high-resolution files, many manufacturers default to the pixel-binned resolution to decrease phone storage. However, due to the small sensor size, noise is still an issue with smartphone cameras. Thus, digital technology was employed to improve this shortcoming, but it went even further. Computational technology is now able to control the illumination of a scene through algorithms that can relight, enhance, and/or blur the whole or parts of an image. With some smartphone cameras, by the time one presses the shutter button the camera has acquired numerous frames at long exposure, fast shutter speed, and standard speed, in addition to the intended shot. All those files are then merged, analyzed, and processed for noise and details, pixel by pixel, to generate the final image. Human skin/hair receives the highest level of detail, whereas other areas of the image receive less attention. Apps are now available with the power to access, modify the original depth of field, and refocus almost any image. All of us who do intraoral photography understand clearly how all the aforementioned features would be a great ally to our photographic skills.

The quality of smartphone videos also has significantly improved, with 4K video resolution now available for most smartphones. But more impressive is the extended dynamic range and the cinematic-like in-body video stabilization that some smartphones have available. In extended dynamic range mode, the camera is actually taking dual-exposure videos at a normal exposure frame together with a short exposure frame (for instance, 120 and 60 frames per second) and combining them on the spot to create a single frame without any further processing. Moreover, smartphone apps are capable of creating 3D face scans that can be exported as STL or OBJ files.

With all this technology in everyone’s hands, it is no wonder that the digital camera market continues to shrink. The Camera & Imaging Products Association (CIPA) has reported a huge drop in global digital camera shipments from 2017 to 2019, as well as a decline in sales for all major camera manufacturers.1

Despite its features and convenience, photographing extra- and intraorally with a smartphone poses an ethical dilemma: Is it permissible to store patients’ electronic protected health information (ePHI) on a personal device? In the United States there are strict regulations that safeguard patient health information (Health Insurance Portability and Accountability Act, HIPAA2), and dental practices are responsible for implementing policies to protect personal information. In 2006, the Health Information Technology for Economic and Clinical Health (HITECH) Act3 expanded the concept of ePHI protection and places liability on the practice to maintain HIPAA and HITECH compliance. The US Government has created a webpage with more information on privacy and security of using mobile devices, and it is worth your time to take a look.4

The digital disruption affects our personal and working lives almost every day, and the understanding of its power and, more importantly, its limits can only benefit our practices, patients, and treatments. I welcome you to experience the magnificent collection of opinions and techniques that challenge the boundaries between digital technology and dental art.

3 https://www.hhs.gov/sites/default/files/ocr/privacy/hipaa/administrative/enforcementrule/enfifr.pdf

4 https://archive.healthit.gov/providers-professionals/your-mobile-device-and-health-informationprivacy-and-security

Jin-Ho Phark, DDS, Dr Med Dent
University of Southern California Los Angeles, California

Neimar Sartori, DDS, MS, PhD
University of Southern California Los Angeles, California

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Bilateral Cleft Palate with Palate Involvement: Putting All in Place for an Esthetic Restoration

Photopolymerization: Scientifi c Background and Clinical Protocol for Light Curing Indirect Bonded Restorations

The Pillars of Full-Mouth Rehabilitation: A Minimally Invasive, Low-Cost Approach to Prosthetic Treatment

The Cllones Library: Three-Dimensional Replication of Natural Dentition with CAD/CAM Restorations

Paulo Kano/Priscila Thiemi Saito Campos/Emerson Lacerda da Silva/ Rafael da Silva Ferro/Sillas Duarte, Jr

3D Magic MakeUp: Building Naturalness and Character in Monolithic CAD/CAM Restorations

Paulo Kano/Priscila Thiemi Saito Campos/Emerson Lacerda da Silva/ Rafael da Silva Ferro/Sillas Duarte, Jr

Biologic Esthetics by Gingival Framework Design: Part 4. Prosthetic Management of Marginal Gingiva Around Natural Teeth

Digital Workfl ow f or 3D-Printed Interim Immediate Complete Dentures: The One-Appointment Approach

Self-Glazing Liquid Ceramics: A Groundbreaking System to Enhance Esthetics of Monolithic Restorations Without Compromising Strength

Optimal Tooth Preparation with Different Tooth Reduction Guides: Case Presentation

Carlos Alberto Jurado/Juliana Branco Da Costa/Jose Villalobos Tinoco/ Heriberto Ureta Valenzuela/Luis Felipe Camara Chejin

Clinical Approach to Fulfi ll Esthetic Requirements: The Challenge of Nature’s Beauty

The Injection Resin Technique: A Novel Concept for Developing Esthetic Restorations

Victor Clavijo, DDS, MS, PhD1
Paulo Fernando Mesquita de Carvalho, DDS, MS2
Cristiano Soares, CDT3

1 Visiting Professor, Advanced Program in Operative and Adhesive Dentistry, Division of Resorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA.

2 Director, Advanced Program in Implantology and Restorative Dentistry, ImplantePerio Institute, São Paulo, Brazil.

Correspondence to: Dr Victor Clavijo, Rua das Orquídeas 667, Sala 1011, Torre Medical, Indaiatuba, São Paulo, Brazil 13345-040. Email: clavijovictor@yahoo.com.br

The importance of three-dimensional (3D) positioning for proper implant placement is well established.1 However, in cases with esthetic-functional involvement, asymmetric gingival margins often generate uncertainty regarding the ideal depth for immediate implant placement. This potentially leads to an implant with a shallow or deep coronoapical position, which will require several appointments for peri-implant profile manipulations to achieve satisfactory results.

To avoid this uncertainty and potential shortcoming, the definitive gingival margin should be established before planning the implant placement surgery. Decision-making guidelines for tissue manipulation and abutment material selection have been reported earlier (Clavijo and Blasi2). In order to transform margins from unfavorable to favorable, treatment planning should be performed before tooth extraction, followed by customization of the gingival architecture.

Even in conventional soft tissue manipulation, prosthetic reconnections3–5 are necessary due to removal of the provisional. This may lead to some bone resorption and subsequent tissue recession from repeated injury to the tissue seal and to the biologic equilibrium around the implant and abutment connection. The one-abutment, one-time concept has been described to improve stability of the bone-implant interface,6–9 but such a technique would be hard to reproduce given the difficulty to manipulate the peri-implant tissue when the abutment cannot be removed and in cases of cement-retained prostheses.

A clinical alternative to keep both the bone-implant interface and peri-implant epithelium intact is the one-time intermediate abutment approach following placement of immediate implants or placement of implants with a tapered internal connection in healed sites. This allows for peri-implant tissue manipulation with more favorable bone remodeling and fewer reconnections that can damage the peri-implant tissue (Box 1). Key factors for the use of the immediate implant protocol after extraction include the residual bone, gingival margin position, buccal bone characteristics, and tissue biotype.10 This article presents a case to describe the step-by-step application of the one-time intermediate abutment.11

Advantages

• No reconnection around the implant neck; no aggression of the gingival seal formed around this area with the prosthetic connection

• More stable bone remodeling and more predictable maintenance of tissues around this connection

• Improved patient comfort during tissue-manipulation appointments

• Single body without access screw, platform switch, and gold coloration, allowing for increased amount of gingival tissue and superior esthetic quality (in terms of light reflection through thin gingiva)

• Reversibility and retrieval of component if necessary

Disadvantages

• The higher the intermediate abutment, the lower the possibility of peri-implant tissue manipulation

• Need for additional prosthetic components for fabrication of the restoration

A 46-year-old woman came to the dental office reporting mobility of the maxillary right central incisor. The tooth had an all-ceramic crown with a fiberglass anatomic post-and-core composite resin restoration that had been fabricated approximately 10 years earlier. In addition, the patient was unhappy with the esthetics of her teeth, particularly their size and color, as well as the black spaces.

After clinical (Figs 1a to 1d), radiographic, and tomographic (Fig 1e) examinations, a fistula in the buccal area of the tooth (with suppuration and 9.0-mm probing depth) was observed, demonstrating partial loss of the buccal wall (confirmed by tomography) and suggesting longitudinal root fracture.

1. Pre-extraction planning to define the final height of the gingival margin of the failing tooth through Digital Smile Design (DSD), initial impression-taking, and planning of the guided surgery

2. Surgical and prosthetic procedures for immediate implant placement, one-time intermediate abutment, and maintenance of the gingival and bone architecture of the tooth site

3. After 6 months of peri-implant tissue stability, peri-implant manipulation until margins are stable

4. Removal of unsatisfactory restorations, preparation of teeth, and final impression of teeth and implant

After decoronation of the maxillary right central incisor and clinical confirmation of the root fracture, an impression was taken for planning and laboratory preparation of the surgical guide.

The buccal volume of the extracted ceramic crown was reduced from its emergence profile, along with any occlusal contacts (at maximum intercuspal position and excursive movements) to prevent displacement during healing of the fistula through medication. The ceramic restoration was reseated with zinc phosphate cement, and the patient was provided instructions and dismissed.

The DSD was performed from the extraoral and intraoral photographs. The cementoenamel junction of the maxillary left central incisor was the reference for the final gingival margin (Fig 2) to achieve an optimal esthetic result in terms of tooth proportion.

The patient’s files (DICOM and STL) were sent to the planning center (MCENTER, MSOFT Virtual Planning Process, Israel) to fabricate the surgical guide for implant placement. Implant placement was planned according to the 3D positioning and at 5 mm from the planned gingival margin of the adjacent tooth (in this case, the cementoenamel junction of the maxillary left central incisor) (Fig 2).

After the ceramic crown was removed, minimally traumatic extraction was performed upon visual confirmation of the root fracture (Figs 3a to 3c), followed by careful cleansing of the socket (Fig 3d) and buccal soft tissues. With the aid of a periodontal probe (Figs 3e and 3f), it was possible to carefully determine the extent of the bone defect in the buccal wall12,13 (classified as wide/deep according to the immediate implant placement protocol of Joly et al14).

Guide drilling (MGUIDE) and implant placement procedures were performed according to the digital planning. The implant (V3, 3.9 × 13 mm, MIS Implants) was inserted, achieving a primary stability of over 45 Ncm (Figs 4a and 4b), which allowed for immediate provisionalization and placement of the one-time intermediate abutment (MIS Connect) (Figs 4c and 4d) with a 30-Ncm torque. The aim was to place the intermediate abutment at least 1 mm away from the future bone margin to improve the bone remodeling, since disconnection will take place above the bone level. Pick-up of the provisional was performed by joining the ceramic crown and the provisional metallic abutment. Criteria used for defining the peri-implant profile are described in Fig 5. As previously mentioned, the one-time abutment was placed in the subcrestal peri-implant area to create space between the connection and the bone-implant interface, thus optimizing bone remodeling. In the subcritical area, a concave profile was planned approximately 1 mm below the gingival margin to create space for the connective tissue graft and the clot. The critical cervical contours of the crown were maintained mesiodistally by slight reduction of the buccal and lingual emergence angle in an attempt to migrate the gingival margin coronally, following the decision tree on how to determine the critical or cervical contour of the provisional in immediate implants (Fig 6).

The provisional restoration was polished and cleaned following a protocol published elsewhere.15

The provisional restoration was delivered, after which a mixed flap was performed using the tunnel technique at the site of the maxillary central incisors (Fig 7a) in order to create space for a connective tissue graft and allow for the flap to cover the recessions of the involved teeth. A properly sized connective tissue graft (Fig 7b) was removed from the palatal region for the treatment of both teeth. The graft was positioned subgingivally, close to the gingival margin, and stabilized by sutures at both ends (Figs 7c to 7e).

A resorbable membrane (Geistlich Bio-Gide Shape) was then inserted in the external portion of the socket, beneath the periosteum (Figs 8a and 8b). The membrane should be supported by healthy bone at least 3.0 mm laterally and apically. Excess membrane should be maintained to facilitate positioning and stability until the biomaterial is packed.

The biomaterial (Geistlich Bio-Oss Collagen) was trimmed and adapted to the shape of the defect. The first portion should be inserted below the membrane, reconstructing the lost wall portion. Other portions should be placed over any existing spaces so that they may be filled. The membrane can be trimmed close to the gingival margin or folded and placed toward the buccal aspect (Figs 8c and 8d).

The provisional restoration with the properly defined contour was screwed with a torque of 30 Ncm, allowing for the support of the papillae and sealing of the reconstructed socket. Flap and graft tension sutures anchored at the contact points were accomplished at the proximal spaces, allowing for the coronal advancement of both the flap and graft (Figs 8e and 8f).

Six months after the graft placement, peri-implant tissue stability was achieved (Figs 8g and 8h) and peri-implant tissue manipulation was initiated. The surgical protocol was performed to obtain a margin coronal to adjacent tissue with a volume greater than 2 mm, limiting the prosthetic manipulation only to the restoration of the cervical contour or critical contour16 with volume addition in this area.2 For a precise determination of this margin, the technician performed the diagnostic wax-up, defining the correct gingival margin height (Figs 9a to 9e). The provisional was removed and flowable composite resin was added for manipulation of the margin.

The unsatisfactory restorations were removed and composite resin restorations were placed. The teeth were prepared for ceramic veneers following the vertical axis of insertion in order to favor the closure of the black spaces and manipulation of the papillae (Figs 10a to 10f). Transfer digital and analog impressions were obtained and sent to the laboratory with shade and shape information.

After the cast fabrication, a digital workflow in the laboratory was undertaken. First, a zirconia abutment was fabricated on the titanium link (MIS Ti-Base CONNECT), replicating the preparation shape with a slight labial reduction for subsequent ceramic application to mimic the shade of the adjacent teeth and to create a bonding area on the abutment (Figs 11a to 11g). This procedure favors the adhesive cementation and matching of the substrate. After the shade and shape equilibrium was achieved, the teeth and abutment were scanned again to obtain the digital design of the ceramic veneers (Fig 12a) following the reference of the initial diagnostic wax-up.

The ceramic veneers were milled in wax and then injected with lithium disilicate (e.max Press, Ivoclar Vivadent). After finishing, the veneers were characterized and glazed, and the final polishing was performed (Figs 12b to 12h).

After removal of the provisional, any residues of temporary cement were removed, the abutment was placed, and the ceramic veneers were individually tried-in for their adaptation (Figs 13a and 13b). All the veneers were then placed to check the contact points (Fig 13c). After the “dry” test, a glycerin-based paste (Variolink Esthetic LC, Ivoclar Vivadent) was used to perform the try-in. The patient approved the shape and color, and the cementation of the ceramic veneers proceeded.

Rubber dam isolation was performed with thick rubber sheets (Nictone), a rubber dam adult frame, and 212 Hu-Friedy clamps (Figs 14a and 14b).

The veneers were individually bonded using light-cured resin cement (Variolink Veneer, Ivoclar Vivadent) following the etching protocol for lithium disilicate with 5% hydrofluoric acid for 20 seconds, followed by rinsing and drying. To remove glass particle debris, 37% phosphoric acid was applied, followed by rinsing and drying. Silane was subsequently applied for 60 seconds and air dried, after which a thin layer of adhesive was placed, air-thinned, and left uncured. Enamel was etched with 37% phosphoric acid for 30 seconds, and dentin areas were etched for only 15 seconds. Etched enamel and dentin were thoroughly rinsed and dried with a gentle airflow and absorbent paper. A thin layer of adhesive was applied using a disposable applicator, followed by gentle airflow to remove the excess and promote solvent evaporation. The adhesive resin was light cured for 20 seconds.

The luting material was placed inside the veneers, which were positioned on the tooth surfaces. Excess cement was removed, and light curing was performed for 40 seconds. Glycerin was placed at the tooth-ceramic interface to prevent oxygen inhibition and improve the polymerization process at the veneer margins (Figs 14c to 14h).

The veneer on the implant abutment was bonded following the protocol described by Clavijo et al17 for bonding feldspathic ceramic with lithium disilicate structure (Figs 15a to 15i).

After cementation, the excesses were removed with a #12D scalpel, and margins were polished with composite resin rubber polishers. Occlusal adjustments were performed and radiographs were taken for control. One-week and 2-year follow-up images are shown in Figs 16 and 17.

The one-time intermediate abutment is a new option to optimize bone remodeling and to increase the amount of tissue volume around implants. The abutment should be placed at least 1 mm above the future bone margin with a torque of 30 Ncm. With the one-time immediate abutment it is possible to protect the interface surrounding the peri-implant bone and mucosa, while providing the opportunity to customize the emergence profile using a screw-retained prosthesis.

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2. Clavijo V, Blasi A. Decision-making process for restoring single implants. Quintessence Dent Technol 2017;40:66–88.

3. Abrahamsson I, Berglundh T, Lindhe J. The mucosal barrier following abutment dis/reconnection. An experimental study in dogs. J Clin Periodontol 1997;24:568–572.

4. Koutouzis T, Gholami F, Reynolds J, Lundgren T, Kotsakis GA. Abutment disconnection/reconnection affects peri-implant marginal bone levels: A meta-analysis. Int J Oral Maxillofac Implants 2017;32: 575–581.

5. Rodríguez X, Vela X, Méndez V, Segalà M, Calvo-Guirado JL, Tarnow DP. The effect of abutment dis/reconnections on peri-implant bone resorption: A radiologic study of platform-switched and non-platform-switched implants placed in animals. Clin Oral Implants Res 2013; 24:305–311.

6. Degidi M, Nardi D, Piattelli A. One abutment at one time: Non-removal of an immediate abutment and its effect on bone healing around subcrestal tapered implants. Clin Oral Implants Res 2011;22:1303–1307.

7. Atieh MA, Tawse-Smith A, Alsabeeha NHM, Ma S, Duncan WJ. The one abutment-one time protocol: A systematic review and meta-analysis. J Periodontol 2017;88:1173–1185.

8. Canullo L, Omori Y, Amari Y, Iannello G, Pesce P. Five-year cohort prospective study on single implants in the esthetic area restored using one-abutment/one-time prosthetic approach. Clin Implant Dent Relat Res 2018;20:668–673.

9. Perrotti V, Zhang D, Liang A, Wang J, Quaranta A. The effect of one-abutment at one-time on marginal bone loss around implants placed in healed bone: A systematic review of human studies. Implant Dent 2019 Aug 1 [Epub ahead of print].