An Injection Layering Technique of Bonded Provisional Veneers at the Early-stage Crown Lengthening: A Case Report
Corresponding Author: Alisa Tapananon, Phyathai 2 Hospital Dental Center, Phyathai 2 Hospital, Bangkok, Thailand, Phone: +66 26172444, e-mail: firstname.lastname@example.org
Received on: 05 April 2023; Accepted on: 10 May 2023; Published on: 23 June 2023
Esthetic crown lengthening followed by ceramic veneers can be performed for a patient with a gummy smile and defective teeth. However, definitive ceramic veneer restorations can be achieved after 3–6 months of surgery. During the healing period, provisional splint veneers for esthetic prototypes with conventional technique may create uncleanable interproximal areas, which leads to inflammation and interference with the healing process. This case report demonstrates a workflow of an injection layering technique for a patient with a gummy smile and discolored and worn teeth. At the early stage of esthetic crown lengthening, flowable composite resins are injected into transparent silicone index fabricated from a diagnostic wax-up, including cut-back and internal stain to mimic the internal characterization of the incisal edge of natural tooth color to create a long-term provisional nonprep veneer. The use of this technique with a simple and predictable workflow allows patient for function and evaluates phonetics, lip support as well as a highly esthetic outcome.
How to cite this article: Tapananon A, Kamolroongwarakul P. An Injection Layering Technique of Bonded Provisional Veneers at the Early-stage Crown Lengthening: A Case Report. Int J Prosthodont Restor Dent 2023;13(2):114-119.
Source of support: Nil
Conflict of interest: None
Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.
Keywords: Case report, Early-stage crown lengthening, Esthetic crown lengthening, Injection flowable composite, Layering technique, Provisional restorations
The purpose of the crown lengthening procedure in the esthetic zone is to manage a variety of clinical situations, such as subgingival caries, crown or root fracture, altered passive eruption, cervical root resorption, and short clinical crown height.1 When a smile displays an excessive amount of gingiva or a gummy smile, an esthetic crown lengthening procedure is commonly performed in order to reduce gingival display and create symmetry and harmony between the maxillary gingiva and the upper lip to improve personal appearance.2-5
In the restorative-driven crown lengthening procedure, the timing of teeth preparation and provisionalization (TPP) after surgery can be classified as intraoperative TPP, early-stage TPP, and delayed-stage TPP.6 In the intraoperative approach, TPP will be carried out during the surgical visit of the crown lengthening procedure. This technique has the advantages of ease of cement remnant removal and the elimination of root proximity and undercuts. However, bleeding control is a crucial step to achieve during the provisional relining procedure. In the early-stage approach, TPP is consequently performed after 3 weeks of the surgical phase, whereas a 6-month healing period will be anticipated prior to TPP in the delayed-stage approach.7
The bonded functional esthetic prototype is a long-term provisional restoration that was bonded until definitive treatment can be achieved.8 The provisional esthetic prototype can be performed precisely with the advent of new materials and placement techniques, flowable composite resin with a high filler loading (69% wt), and homogenous distribution of filler has been introduced, which leads to their application in restoring with a minimally invasive approach.9 The injection technique using flowable composite is a simple additive technique to restore contours and shape of worn-out, discolored, or defective teeth. A clear vinyl polysiloxane impression material is used to replicate the diagnostic wax-up. A clear matrix can be applied over the patient’s teeth and used as a template for the injectable composite.10,11 With this technique, only a single shade of flowable composite was injected, which is not able to mimic the internal characterization of the incisal edge of natural tooth color. In this respect, the use of cut-back and internal stain followed by injection of a high translucent flowable composite may lead to favorable esthetic outcomes.
This case report describes a procedure for long-term provisional restorations using conventional diagnostic wax-up, data merging, and computer-aided design (CAD) and computer-aided manufacturing milled surgical guide for an esthetic crown lengthening procedure. At the early stage of esthetic crown lengthening, an injection layering technique was performed. The flowable composite resins are injected into a transparent silicone index fabricated from a diagnostic wax-up to create a long-term provisional nonprep veneer.
A 41-year-old female presented with the chief complaint of ”I am not satisfied with my smile due to my gummy smile and short and discolored teeth.” This patient presented at the Dental Center, Phyathai 2 Private Hospital, Bangkok, Thailand. Her major concern was an unesthetic appearance, and she desired to restore maxillary teeth with a natural look (Fig. 1A). Clinical examination presented an incisal display at the rest position was 1 mm (Fig. 1B). The diagnosis was an excessive gingival display from #5 to #12, brown calcification on facial surfaces of #5 and #12, and worn teeth on #7–#10. The patient had completed orthodontic treatment for 3 years and was satisfied with her tooth alignment. Extraoral and intraoral photographs were used for smile design to create a new gingival level, zeniths position, teeth proportion, shape, and incisal planes to be in harmony with upper and lower lips.
The following treatment plan was explained to the patient, and she accepted the same—periodontal surgery followed by esthetic crown lengthening to reduce gingival display. Correction of the teeth proportion on teeth #5–#12 with a 6-month healing period. A provisional bonded esthetic prototype (nonprep) is to be given at the early-stage healing of crown lengthening with the injection layering technique. Lithium disilicate ceramic veneers to restore the upper teeth after a 6-month healing period
Esthetic Crown Lengthening
Data from a digital smile design on teeth #5–#12 was used to determine the amounts of gingival reduction (Figs 1C to E) and was transferred to the maxillary cast to fabricate a periodontal stent. A clear polymethyl methacrylate was milled according to CAD design (Fig. 1F). Esthetic crown lengthening was performed on the left upper premolar to right upper premolar under local anesthesia (4% articaine with epinephrine 1:100,000). The surgical stent was inserted, and the gingivectomy outline was marked using a 15c blade. The internal bevel incision was performed (Fig. 2A). After removing the free gingival tissue, the papilla area is elevated split-thickness in order to prevent loss of the interdental papilla. A full-thickness mucoperiosteal flap was elevated (Fig. 2B). The ostectomies were carried out to create the 3 mm space between the final restorative margin and the alveolar crest to recreate the biologic width (Fig. 2C). Osteoplasties were made in order to eliminate excess contour of the buccal bone and recreate the physiologic osseous morphology (Fig. 2D). The flap was repositioned (Fig. 2E). Each interdental papilla was stabilized by vertical mattress suture using 6–0 monofilament suture (6–0 Prolene, Ethicon/Johnson & Johnson, Somerville, New Jersey, United States of America). The patient was called after 2 weeks for the removal of the sutures (Fig. 2F).
At the early stage of crown lengthening 1-month after periodontal surgery, the diagnostic wax-up was performed according to gingival margins to create the ideal proportion of anterior teeth (Fig. 3A). A transparent custom tray was used with a clear polyvinyl siloxane (PVS) (EXACLEAR; GC Corp, Bangkok, Thailand) to make an impression of the diagnostic wax-up cast (Fig. 3B). This method ensured the surface texture and contours of the restorations. Access holes were made as the size of the flowable composite tip through the clear PVS material slightly facial to the incisal edge of each tooth that was to be restored (Fig. 3C).
A Provisional Bonded Esthetic Prototype with the Injection Layering Technique
This procedure was started 1 month after periodontal surgery (Fig. 4A). Before the adhesive procedure, teeth #5–#12 were cleaned with pumice, rinsed, and air-dried, followed by applying teflon tape on teeth #6, #8, #10, and #12 (Fig. 4B). Nonprotected teeth were etched with 35% phosphoric acid (Ultra-Etch™, Ultradent Products Inc, South Jordan, Utah, United States of America) on the enamel surface for 30 seconds, rinsed, and gently air-dried (Fig. 4C). A universal adhesive (G-Premio Bond, GC America; Alsip, Illinois, United States of America) was applied to the etched surface, air-dried for 5 seconds, and light-cured using an light emitting diode curing light for 20 seconds (DEMI PLUS, Kerr, Wisconsin, United States of America) (Fig. 4D). The clear matrix was placed and held firmly while the flowable composite (shade BW, G-aenial Universal Flo, GC America) was injected through an access hole of silicon index for the restoration of the first set of teeth. The flowable composite was light-cured through the clear matrix on the facial and lingual surfaces for 40 seconds each (Figs 4E and F). Subsequently, the same procedure was repeated for the remaining teeth (Figs 5A to C). Approximately 0.3 mm. artificial enamel layer of the composite resin veneer was removed on teeth #7–#10 (Fig. 5D). Internal characterization was performed with a diluted gray to create an internal translucent and white tint to create a halo effect (Kolor + Plus™, Kerr, United States of America) and light-cured for 40 seconds (Figs 5E and F).
The previous clear matrix was placed over teeth #7–#10, and a clear translucent flowable resin composite (JE, G-aenial Universal Flo) was injected through the hole filling the entire artificial dentin layer, followed by light-cure on the facial and incisal surfaces for 40 seconds each. The injection technique with applying these modifiers and tints onto cut-back dentin structures followed by the injection of translucent enamel can create the three-dimensional effect within the incisal edge (Fig. 6A). The patient was very satisfied with this long-term provisional bonded prototype with highly esthetic outcomes and reported no postoperative pain after surgery (Fig. 6B). The patient was able to maintain oral hygiene regularly due to the flowable composite was bonded on each tooth separately.
This case report describes the provisional prosthetic steps after the initial healing has occurred without interfering with the reestablishment of the biological width during the maturation phase of soft tissues. In the first 3 weeks after surgery, approximately 1 mm of the bone surrounding the teeth involved in the surgery resorbs and leaves a portion of healthy root cementum available for connective tissue attachment to reform in a more apical position.7 Fabrication of long-term provisional restoration in this stage allows the patient not only for function but also for esthetic appearance.
In the past, composite restorations could only be placed directly and manually; this might be a time-consuming technique. With the use of highly filled flowable composite resins and clear silicone matrix technique, this approach significantly reduces the technique sensitivity while providing accurate and predictable esthetic outcomes for the provisional bonded esthetic prototype.12-15 The integration of high filler loading (69% wt) and homogenous distribution of filler leads to improve fracture toughness and flexural strength of provisional restoration. Moreover, using of cut-back technique with internal stain and injection of flowable enamel composite resins can create a more translucent effect at the incisal edge, which leads to mimicking the natural tooth characteristic.16 Since this technique is mostly used for long-term provisional restorations, it should be considered for clinicians to apply this workflow for different clinical situations.
The provisional prosthetic restoration phase can be performed 3 weeks after the periodontal surgery in order not to interfere with the reestablishment of the biologic width and to condition the soft tissues during the period of maximal regrowth.6 At the early stage, a long-term provisional prototype can be simply performed with the injection layering technique. This technique, including cut-back and internal stain, can mimic the internal characterization of the incisal edge of natural tooth color. This long-term provisional bonded prototype will also serve as a preparation guide for definitive ceramic veneers preparation.
Alisa Tapananon https://orcid.org/0000-0002-5847-1433
Pongrapee Kamolroongwarakul https://orcid.org/0009-0000-4808-7537
3. Trushkowsky R, Arias DM, David S. Digital smile design concept delineates the final potential result of crown lengthening and porcelain veneers to correct a gummy smile. Int J Esthet Dent 2016;11(3):338–354. PMID: 27433549.
5. Mendoza-Azpur G, Cornejoc H, Villanueva M, et al. Periodontal plastic surgery for esthetic crown lengthening by using data merging and a CAD-CAM surgical guide. J. Prosthet Dent 2022;127(4):556–559. DOI: 10.1016/j.prosdent.2020.09.041
7. Zucchelli G, Mazzotti C, Monaco C. Standardized approach for the early restorative phase after esthetic crown-lengthening surgery. Int J Periodontics Restorative Dent 2015;35(5):601–611. DOI: 10.11607/prd.2444
8. McLaren EA. Bonded functional esthetic prototype: an alternative pre-treatment mock-up technique and cost-effective medium-term esthetic solution. Compend Contin Educ Dent 2013;34(8):596–607. PMID: 24564612.
13. Gestakovski D. The injectable composite resin technique: minimally invasive reconstruction of esthetics and function. Clinical case report with 2-year follow-up. Quintessence Int 2019;50(9):712–719. DOI: 10.3290/j.qi.a43089
15. Hosaka K, Tichy A, Hasegawa Y, et al. Replacing mandibular central incisors with a direct resin-bonded fixed dental prosthesis by using a bilayering composite resin injection technique with a digital workflow: a dental technique. J Prosthet Dent 2021;126(2):150–154. DOI: 10.1016/j.prosdent.2020.05.007
16. Terry D A, Powers JM, Blatz MB. The inverse injection layering technique. J Cosm Dent 2018;34(1):48–62.
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