Case reports presenting recreation of gingival profile through laser-assisted recontouring and provisional restorations in implant-supported prostheses

Abstract

Exquisite esthetics for implant-supported restorations in the anterior esthetic zone is a challenging task. Recreating the gingival profile with proper integration of hard and soft tissues is a prime requisite to overcome the clinical challenge. Abutment selection, impression technique, and emergence profile of the final restoration play an important role in providing a distinct appearance to the final prosthesis. Through two case reports, this paper describes the step-by-step procedures involved in customizing the emergence profile and gingival profile using laser-assisted surgery and provisional restorations.

INTRODUCTION

Obtaining optimal esthetic outcome in implant-supported restorations in the esthetic zone poses a clinical challenge. The success and effectiveness of an implant-supported restoration in the esthetic zone depend on its seamless integration with the adjacent teeth, thus becoming indistinguishable in appearance. Esthetics and health of implant restorations are governed by factors such as residual alveolar bone, peri-implant soft tissue, and crown form. The physiological crown form plays an important factor in maintaining the periimplant health.[1] Implant-supported restorations should show a good emergence profile to maintain hygiene, gingival health, and appearance. In 1977, Stein and Kuwata coined the term “emergence profile” to describe tooth and crown contours as they traversed soft tissue.[2] GPT-9 defines emergence profile as the contour of a tooth or restoration, such as the crown on a natural tooth, dental implant, or dental implant abutment, as it relates to the emergence from circumscribed soft tissue.[3] Thus, the emergence profile for an implant-supported restoration can be described as the portion of a restoration emerging coronally from the free gingival margin to replace the crown form of the tooth being replaced.[4]

Pink and white (i.e., gingiva and tooth structure, respectively) are components of the smile architecture where the two colors complement each other and must be in harmony with one another with respect to color, texture, shape, polish, and stippling or microtexture. Thus, the aesthetics of a smile are greatly influenced by the condition and look of the gingival tissues.[5] Dentists and technicians are highly skilled in recreating teeth, which is the white part of a smile. However, as the framework for the teeth is represented by the gingival architecture, the final three-dimensional esthetic result will be compromised if it is not restored properly, either surgically or with a prosthesis.[4]

The harmony between white aesthetics and pink aesthetics is enhanced by the correct spatial positioning of the gingival zenith (GZ). Gingival trigone, synonymously known as GZ[5], is the most gingival point of curvature along the free gingival margin of a tooth. Zenith points are essential in establishing the pink esthetics by assuring that the teeth, lips, and gingiva are in harmony with each other. It helps to determine the desired axial inclination of the tooth by maneuvering the line angle of the tooth vertical axis and in maintaining the natural slopes and curves of the gingiva around the teeth when viewed from the anterior aspect. Smile designing can become markedly more precise when tooth angulations and subsequent treatment plans work in unison with the determined zenith points.[6,7]

Zenith points are precisely oriented in the mesiodistal and apicocoronal orientations. It is situated mesiodistally, simultaneous with the long axis of the lateral incisor (LIs) and just distal to the long axis of the central incisor (CIs) and ipsilateral canine (Cs). On the CIs and Cs, the apicocoronal zenith is at the same height, while on the LIs, it is somewhat coronal. Visibility of interdental papilla enhances the esthetics of smile.[5,8,9]

To achieve the emergence profile for implant-supported restorations Davarpanah et al.[10] put forward a three-stage approach, which included the implant stage, intermediate abutment stage, and final crown insertion stage. During the implant placement stage, appropriate selection of implant diameter and position in harmony with crestal morphology is required, as the implant differs significantly from a tooth in terms of possessing a smaller circumferential diameter.[11,12]

At the intermediate abutment stage, proper selection of healing abutment, and soft tissue modification to enhance gingival recontouring is needed. Soft tissue modification can be achieved surgically with a surgical knife, the use of electrosurgery, and lasers. Nonsurgical methods include the use of wide temporary healing abutments, prosthetically induced gingival alterations using prefabricated advanced anatomic abutments, custom abutments, ceramic abutments, and commercially available emergence profile management system using silicone index (e.Julldent) [Figure 1] whose design parameters have not yet been published. The cervical contouring concept by Bichacho and Landsberg emphasized on the utilization of a provisional restoration to reshape the soft tissues around the implant.[3,13]

Figure 1.

Commercially available gingival former customization silicone index (Julldent)

In the definitive final restoration placement stage, transfer of the contoured gingival profile to the working model, fabrication of the final prosthesis with correct anatomic morphology, shade, choice of material and a harmonious relationship with the created gingival architecture is mandatory.[3,11,12,13]

This article presents two case reports with a detailed description of procedures involved in creating an emergency profile for implant-supported anterior restorations through the use of LASER-assisted and custom-made provisional restoration for shaping of the periimplant soft tissues.

CASE REPORTS

Case 1

A 32-year-old female patient was referred from the department of oral and maxillofacial surgery for replacement of the missing maxillary right LIs [Figure 2a]. Previous dental history revealed the placement of a dental implant (NR Line Implants, Dentium USA; 3.6 mm × 9 mm) [Figure 2b] 9 months back following loss of tooth due to a road traffic accident 5 years prior. The patient was systemically healthy and not under any long-term medication.

Figure 2.

(a) Preprosthetic intraoral view; (b) Radiographic image of implant placed; (c) Laser-assisted soft tissue contouring done; (d) New temporary crown placed

Details of the second stage surgery for uncovering of implant were explained to the patient. As the overall oral hygiene was fair and the intended surgical site did not show any evidence of deposits and inflammation, a full-thickness flap was raised under local anesthesia after patient consent. Cover screw was removed, and a temporary plastic abutment was placed. Using tooth moulding acrylic material, a temporary crown was fabricated. Simple interrupted sutures using a resorbable suture material were placed in the interproximal area, and the patient was asked to report back after 2 weeks. When the patient reported back, it was observed that the soft-tissue height was not in harmony with the gingival height of adjacent teeth.

Reshaping of the soft tissue was done to a more cervical level in harmony with the adjacent tooth using a diode laser (980 nm, 10 W; Zolar, Canada) [Figure 2c]. After infiltration with a local anesthetic agent, laser procedure was done using the integrated program of the device with its preset parameters for implant exposure (980 nm wavelength, contact mode, continuous wave, 1 W output power, pulse interval of 0.01 ms to 9.9 s and pulse duration of 0.01 ms to 9.9 s). The optic fiber used was 300 µm. The soft tissue contouring was done using a brushing motion with the fibre kept perpendicular to the tissue margin. Laser application was intermittently stopped after every 2–3 s to check for any burning effects on the soft tissues and avoid any temperature increase.

A new provisional crown was fabricated according to the newly obtained soft tissue margin [Figure 2d]. Long contacts were provided on the mesial and distal aspects. Provisional restoration was luted using a provisional luting cement (zinc oxide eugenol). Patient was advised to use the provisional implant restoration for a minimum of 3 months to allow proper recontouring of the soft tissue complex and was periodically reviewed to ensure that proper oral hygiene was maintained.[8] The provisional restoration was relined and reshaped twice, and thus, the soft tissue was managed and guided to achieve the desired emergence profile. A period of 3 months was allowed for soft tissue stabilization.[14] After stabilization of the recontoured tissue [Figure 3a], a permanent implant abutment (3.6 mm diameter with 1 mm collar height) was connected to the implant and tightened to 15N torque, and a periapical radiograph was taken to verify the definitive seating of the abutment on the implant. An abutment level putty wash impression (GC Flexceed Vinyl Polysiloxane impression material; Japan) was made using the direct impression technique. A master cast was poured, and a porcelain fused to metal cement retained crown was fabricated. The final crown was evaluated clinically and radiographically in terms of accuracy and fit. After a thorough oral prophylaxis, the crown was luted with type 2 glass ionomer cement (GC Gold Label luting and lining cement, GC Corporation; Tokyo, Japan), Figure 3b. Patient was reviewed after 2 weeks initially and then monthly for 6 months.

Figure 3.

(a) Recontoured soft tissues after 4 weeks; (b) Final crown luted

Case 2

A 49-year-old male patient reported to the department of prosthodontics with a chief complaint of a root piece in the upper front tooth region at the right side. Patient was given several treatment options like removable partial denture, tooth/implant-supported fixed partial denture, and immediate implant-supported denture. He opted for implant implant-supported prosthesis.

The root stump was extracted [Figure 4a], and an implant (Frontier, Global Medical Implants, Spain; Regular platform; 3.75 mm × 13 mm) was placed after adequate osteotomy of the extraction site. The jumping distance was filled with a xenogenic bone graft material (Osseograft^®) and the site covered with a bioresorbable barrier membrane (Healiguide^®). A healing abutment was placed, followed by complete flap closure with simple interrupted sutures using a resorbable suture material [Figure 4b].

Figure 4.

(a) Extraction site; (b) Radiographic image of the implant placed with healing abutment; (c) Laser-assisted uncovery of the implant at the second stage; (d) Temporary crown placed

The patient was reviewed after 2 weeks. Healing was satisfactory. The patient was recalled after 6 months for prosthetic crown placement.

When the patient reported back to the department after 6 months, after an evaluation of the intended surgical site for any signs of inflammation, a diode laser (980 nm, 10 W; Zolar, Canada) was used to uncover the healing abutment and recontour the soft tissue [Figure 4c]. The operating parameters used for the laser were the same as that of patient 1. An implant abutment was placed, and a temporary crown was fabricated using tooth moulding acrylic powder [Figure 4d]. The patient was recalled again after 3 months.

When the recontoured soft tissue had stabilized after 3 months, a putty index of the transmucosal portion of the provisional crown was made [Figure 5a]. Using the index, transmucosal contour of the crown was duplicated with pattern resin (Pattern Resin™ LS; GC America Inc.) on the impression coping [Figure 5b-d], and a closed tray impression was made using addition silicone elastomeric impression material (GC Flexceed Vinyl Polysiloxane impression material; Japan). A jig trial was fabricated using the abutment and verified intraorally [Figure 5e], and a periapical radiograph was made to verify the definitive seating of the abutment on the implant. Using the putty index of the transmucosal portion of the provisional crown as a reference, a full metal ceramic screw mentable crown (cement retained crown with a screw access hole) was fabricated [Figure 6a and b].[15] The fit and accuracy of the final restoration were evaluated intraorally and radiographically. After oral prophylaxis, the abutment screw was tightened to 15N torque and the screw access hole was sealed with composite resin [Figure 6c].

Figure 5.

(a) Putty index of the transmucosal portion of the provisional crown; (b and c) Pattern resin used to duplicate the transmucosal contour on the impression coping; (d) Impression coping placed intraorally for closed tray impression technique; (e) Jig trial

Figure 6.

(a and b) Screwmentable final crown similar to the contours of the provisional restoration fabricated using the index as reference; (c) Intraoral view with the final screwmentable crown

DISCUSSION

Despite all the recent advancements in periodontal and peri-implant surgical regeneration techniques, it is still clinically challenging to complete and aesthetically restore the hard and soft tissue shapes. Use of lasers in soft tissue contouring and uncovering of implants in the second stage surgery is well documented. As compared to the traditional scalpel technique, lasers have the advantages of better hemostasis with improved visibility, precise incision margin, minimal surgical trauma with less damage to surrounding tissues, decreased postoperative discomfort and swelling, and better control of tissue depth.[15,16,17] In the presented cases, a 980 nm diode laser was used. The efficacy and safety of diode lasers in second-stage implant surgeries and their ability in not affecting either polished titanium or sand-blasted and acid-etched (SLA) disks have been reported by Bajaj et al. and El-Kholey.[18,19] Based on these reports, it was assumed that selecting a diode laser with its preset parameters would promote better healing with less trauma to the patients selected.

In Case 1, as the location of the zenith point with respect to the maxillary LIs was not in harmony with the adjacent tissue, a laser-assisted contouring was done to achieve optimal zenith point. Maxillary LIs represents the playful part of the smile, and its zenith point is normally located centrally.[20] A well-adapted temporary restoration with long interproximal contacts was given to decrease the cervical embrasure and thus reduce the visibility of the darkness of the oral cavity in the interproximal triangle between the soft tissue and contact area. Long contact between adjacent teeth also prevents food impaction and serves as a major factor influencing speech and cosmetics.

In Case 2, a healing abutment was placed at the time of implant placement to prevent any bone ingrowth as the implant was placed subcrestally, thus allowing enough space in a vertical dimension to create a more harmonious esthetic emergence profile.[10] During the second stage surgery, a diode laser was used to uncover the healing abutment to reduce postoperative discomfort and allow a faster rehabilitation phase.[21,22,23,24] An interim restoration was given to develop an ideal soft tissue contour on the transmucosal surface of the prosthesis.[25] An index of the transmucosal surface of the interim prosthesis was made to transfer the soft tissue contours to the definitive restoration.

Though laser assisted soft tissue contouring is a routinely done chair-side procedure, it can be noted that in both cases, the final esthetic outcome was mainly due to the synergetic effect of the laser and the contours of the provisional restoration. Even though the advantages of lasers in oral implantology are well documented, some limitations still exist. Apart from equipment cost and requirement for specific operator training, the possible clinical disadvantages associated with use of lasers include the positional location of the submerged implant cover screw, and the need for adequate keratinized tissues around the implant.[17,19]

CONCLUSION

During rehabilitation of missing teeth with an implant-supported restoration in the anterior esthetic zone, considerations should be given in achieving a good emergence profile and a harmonious positioning of the zenith points with respect to the adjacent teeth to obtain an optimal esthetic outcome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.