Removable Gingival Prosthesis: A Digital Workflow for a Traditional Treatment

INTRODUCTION

Traditional periodontal surgery offers a multitude of oral health benefits, though it often results in suboptimal aesthetics with clinically large crowns and apically positioned tissue. The teeth increase in clinical length, and loss of soft and hard tissue results in black triangles.^1,2 The aesthetic complications may be ameliorated with surgical or prosthetic treatment, though surgical intervention often proves unpredictable. The current consensus reports mild gingival recessions, such as Miller I and II or Recession Type I lesions, are regenerated predictably, though the aesthetic defects following periodontal surgery often mirror more severe deficiencies and cannot be repaired predictably.^3-6 Additionally, papillary regeneration is unpredictable when interproximal bone is insufficient. Therefore, the use of gingival appliances may be a suitable option to ameliorate deficiencies; moreover, appliances may also be used to deliver medicament or fluoride to patients at risk for cervical decay.⁷ Other treatment alternatives include the use of gingivally colored composite restorations⁸ or gingival porcelain veneers⁹ placed on either natural teeth or final restorations. The use of composite or porcelain on the natural teeth can be associated with hygienic issues,¹⁰ and revealing the pink porcelain-gingival interface in a high smile-line patient can be highly unaesthetic. Other options that avoid the hygienic complications include removable appliances.^11-13 Traditionally, the fabrication of removable gingival appliances includes final impressions that must capture the embrasures accurately. Alginate polyvinyl siloxan, and polyether materials can tear at the embrasures upon retrieval, and rubber-based impression materials can lock onto the embrasures. Additionally, traditional fabrication techniques require a wax-up and final processing on models, so inaccuracies associated with impression irregularities and stone expansion can affect the prosthetic outcome. Traditional approaches are also limited in their ability to quickly and easily reproduce the prosthesis if lost or broken. Most importantly, a try-in prior to final processing is not possible.¹⁴ Lastly, the traditional approach with stone models makes gingival color matching difficult, while an intraoral scan can inform the laboratory more accurately of gingival shading.¹⁵

This case report outlines a novel digital workflow for a traditional treatment modality: fabrication of removable gingival appliances. By using intraoral scanners and 3D printing technology, we were able to digitally plan the removable gingival prosthesis, confirm proper fit and aesthetics, inexpensively print a try-in prosthesis, make necessary adjustments prior to final delivery, and save the file for easy replication if lost or damaged. This article aims to demonstrate the reliability and practicality of the aforementioned workflow, offering an alternative method to a traditional workflow. 

CASE REPORT

A patient presented to the Rutgers School of Dental Medicine for comprehensive evaluation and care in June of 2016. The patient presented to the periodontal clinic and, following an initial exam, was diagnosed with periodontitis stage II generalized grade B and Stage III localized grade B. Probing depths ranged from 3 to 9 mm with clinical attachment loss ranging from 3 to 11 mm. Note that the pertinent sextant in this case presentation was the premaxilla, though the entire dentition was appropriately treated. The premaxilla initially presented probing depths ranging from 3 to 8 mm with increased pocket depth associated with the central incisors and clinical attachment loss ranging from 7 to 13 mm. An original treatment plan was presented and agreed upon by the patient, entailing forced eruption of Nos. 8 and 9 in preparation for implant site development.¹⁶ Although some osseous advancement occurred during tooth extrusion, which leveled the ridge and ameliorated the pocketing, there was inadequate advancement to allow proper implant placement (Figures 1 and 2). The result was severely compromised aesthetics (Figures 3 and 4). The adjusted treatment plan entailed extraction of the central incisors, which would be replaced with fixtures following vertical ridge augmentation or a traditional fixed prosthesis. However, the patient at this time refused to extract central incisors, so the treatment plan necessitated revision as follows: splint anterior maxillary teeth, intentional root canal therapy on central incisors, composite veneers placed in the premaxilla, and delivery of removable gingival prosthesis to allow proper aesthetics and maintenance of existing dentition. This treatment plan was feasible as pocket depths were reduced to 3 to 5 mm, suggesting a maintainable premaxilla, albeit unaesthetic.¹⁷ 

Figure 1. Pre-extrusion radiograph illustrating an angular defect.

Figure 2. Post-extrusion radiograph of the central incisors illustrating leveling of the crest and amelioration of the angular defect though inadequate advancement for implant placement.

Figure 3. Extraoral photograph illustrating jeopardized aesthetics with a natural smile.

Figure 4. Intraoral photograph illustrating inadequate aesthetics for implant site development.

Figure 5. Intraoperative clini- cal photograph during pocket elimination surgery, representative of surgical protocol used in the contralateral sextant.

Figure 6. Clinical photograph following healing of pocket elimination surgery.

Figure 7. Intraoperative clinical photograph during the free gingival graft to ameliorate frenum pull in the lower premolar site and thicken the gingival phenotype.

Figure 8. Clinical photograph immediately following the free gingival graft.

Figure 9. Clinical photograph following healing of the free gingival graft.

Figure 10. Delivery of chairside composite veneers, illustrating improvement of the aesthetic outcome.

Figure 11. Final clinical photograph following delivery of composite veneers on the maxillary central incisors.

Figure 12. Delivery of a fixed palatal retainer, offering stability to the premaxilla.

Figure 13. Three-dimensional printed mockup of the proposed gingival veneer for try-in.

Figure 14. In-mouth try-in of the printed mockup following minor adjustments to confirm proper fit, function, and aesthetics.

Figure 15. Extraoral photograph with printed mockup to visualize aesthetics and prosthetic display with an exaggerated smile.

Figure 16. Receipt of final prosthesis with a denture tooth inserted to aid with the patient’s masticatory function and restoration of the edentulous site.

Figure 17. Intraoral photograph of the final prosthesis inserted and the edentulous site replaced with a denture tooth.

Figure 18. Intraoral photograph illustrating the aesthetics of the final prosthesis, with additional acrylic added to help stabilize the central incisor and add retention to the prosthesis.

Figure 19. Extraoral photograph with the printed final prosthesis to visualize aesthetics and gingival display with an exaggerated smile.

At this time, the patient continued to undergo periodontal therapy, including several quadrants of osseous surgery as well as lower soft-tissue augmentations. At the conclusion of phase 2 therapy, the patient saw pocket depth reduction, adequate attached keratinized tissue, improved oral hygiene, and acceptance of a strict maintenance program—in other words, a stable periodontal condition (Figures 5 to 9). Concurrently, the patient received prophylactic endodontics on centrals to accommodate composite restorations and splinting of canines, laterals, and centrals (Figures 10 and 11). Note that due to the central diastema, which the patient refused to close, the fixed palatal splint included 2 separate units (Figure 12). In order to fabricate the gingival prosthesis, the patient’s dentition and extraoral anatomy were scanned preoperatively via a TRIOS Scanner (3Shape). A digital mockup was designed to allow proper fit into facial embrasures and acceptable gingival aesthetics when smiling. At this time, a prototype was 3D printed for a try-in (Figure 13). At this time, the patient could visualize the final gingival margins, and the clinician could make the necessary changes prior to final processing (Figures 14 and 15). This try-in phase allows modification to maximize retention, for example, with the use of accurately captured embrasure spaces and clasps wrapped around the distal molars. Following minor alterations made simply through the digital workflow, the gingival shade was registered with the scanner, and the final prosthesis was sent for printing. Note that this file is now saved and can be sent to the laboratory for easy duplication if the prosthesis is lost or damaged. Following digital confirmation, the gingival mask was printed in a polyamide material and returned for final delivery. The final prosthesis was delivered, enhancing the patient’s aesthetics, restoring an edentulous posterior molar, and adding physical stability to a reduced periodontium (Figures 16 to 19). Though the prosthesis was delivered passively, 1 mm of repair acrylic was added adjacent to the central incisor chairside to increase retention, a slight revision that was undoubtedly minimized due to the mock-up trial. Due to the digital workflow, rescanning and reprinting the prosthesis could be easily accomplished, however the patient refused to have his central incisors extracted. 

DISCUSSION

Despite clinical advances in aesthetically driven periodontal treatments, some clinical situations yield a poor aesthetic outcome. Aesthetic compromises often include poor white-pink ratios, abnormal clinical crown length-width ratios, and black triangles, all of which are negatively exacerbated in high-smile patients. Addressing these concerns can entail a multitude of modalities—one traditional means being the fabrication and delivery of a removable gingival prosthesis. Traditionally, this treatment entailed the fabrication of a gingival mask via model surgery, followed immediately by processing, delivery, and chairside adjustment of the final mask. This article aims to introduce a novel and digital workflow to fabricate such a gingival prosthesis. Through the use of intraoral scanning and digital planning, the gingival veneer may be designed and 3D printed inexpensively for try-in and adjustment. This minimizes the amount of final adjustments necessary at delivery. Following approval of the try-in by the practitioner and patient, the file may be printed in a flexible thermoplastic material, offering optimal aesthetics. This ensures maximum patient satisfaction and ease of insertion. Moreover, the digital file is saved so that it is easy to provide a duplicate prosthesis to the patient or to refabricate it if the prosthesis is lost.

In addition to expediting the fabrication process, the use of gingival prostheses has potential clinical benefits. The prosthesis provides cross-arch stabilization and decreases tooth mobility, which was demonstrated in this case where the mobility of premaxillary teeth decreased from Grade 2 to Grade 1 when the appliance was in place. The appliance also allows for easy removal by the patient, improving access and quality of oral hygiene. The prosthesis also provides psychological benefits, improving the final aesthetic result and boosting patient satisfaction. 

The process left some questions unanswered, necessitating further research. The use of the prosthesis as a cross-arch stabilization during and after periodontal therapy was postulated. Further work is required to identify and evaluate the efficacy of the material and prosthetic design in stabilizing periodontally compromised teeth. Patient compliance and utilization of the prosthesis also remain to be seen. 

CONCLUSION

To our knowledge, this is the first documented clinical case of a digitally designed gingival prosthesis using CAD/CAM technology, which proved efficient and effective. This approach offers a means to maximize patient satisfaction as well as optimize chair time. The main advantages of this workflow include the following: (1) a digital wax-up, which may expedite the design process; (2) clinicians can inexpensively print a clinical try-in prior to final processing to ensure proper fit, aesthetics, and patient approval, thereby minimizing chairside adjustments at final delivery; (3) compared to alginate and polyether materials that can tear at the embrasures upon retrieval and rubber-based impression materials that can lock onto the embrasures, the digital scan may improve accurate capture of embrasure morphology and thereby increase retentive features of the appliance given it physically engages embrasure space; and (4) file storage for easy replacement.

The use of removable gingival veneers remains a viable treatment option for patients with compromised aesthetics, and this new approach offers a contemporary workflow to the treatment.

REFERENCES 

1. Prato GP, Rotundo R, Cortellini P, et al. Interdental papilla management: a review and classification of the therapeutic approaches. Int J Periodontics Restorative Dent. 2004;24(3):246–55. 
2. Singh VP, Uppoor AS, Nayak DG, et al. Black triangle dilemma and its management in aesthetic dentistry. Dent Res J (Isfahan). 2013;10(3):296-301.
3. Jepsen S, Caton JG, Albandar JM, et al. Periodontal manifestations of systemic diseases and developmental and acquired conditions: Consensus report of workgroup 3 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89 Suppl 1:S237–48. doi:10.1002/JPER.17-0733
4. Richardson CR, Allen EP, Chambrone L, et al. Periodontal soft tissue root coverage procedures: practical applications from the AAP Regeneration Workshop. Clin Adv Periodontics. 2015;5(1):2-10. doi:10.1902/cap.2015.140059
5. Chambrone L, Tatakis DN. Periodontal soft tissue root coverage procedures: a systematic review from the AAP Regeneration Workshop. J Periodontol. 2015;86(2 Suppl):S8-51. doi:10.1902/jop.2015.130674
6. Tatakis DN, Chambrone L, Allen EP, et al. Periodontal soft tissue root coverage procedures: a consensus report from the AAP Regeneration Workshop. J Periodontol. 2015;86(2 Suppl):S52–5. doi:10.1902/jop.2015.140376
7. Blair FM, Thomason JM, Smith DG. The flange prosthesis. Dent Update. 1996;23(5):196–9.
8. Zalkind M, Hochman N. Alternative method of conservative esthetic treatment for gingival recession. J Prosthet Dent. 1997;77(6):561–3. doi:10.1016/s0022-3913(97)70094-5
9. Capa N. An alternative treatment approach to gingival recession: gingiva-colored partial porcelain veneers: a clinical report. J Prosthet Dent. 2007;98(2):82–4. doi:10.1016/S0022-3913(07)60040-7
10. Kamalakidis S, Paniz G, Kang KH,. Nonsurgical management of soft tissue deficiencies for anterior single implant-supported restorations: a clinical report. J Prosthet Dent. 2007;97(1):1-5.
11. Barzilay I, Irene T. Gingival prostheses—a review. J Can Dent Assoc. 2003;69(2):74–8.
12. Ellis SG, Sharma P, Harris IR. Case report: aesthetic management of a localised periodontal defect with a gingival veneer prosthesis. Eur J Prosthodont Restor Dent. 2000;8(1):23–6.
13. Greene PR. The flexible gingival mask: an aesthetic solution in periodontal practice. Br Dent J. 1998;184(11):536–40. doi:10.1038/sj.bdj.4809691
14. Patil S, Prabhu V, Danane NR. Gingival veneer: Mask the unesthetic. J Indian Soc Periodontol. 2011;15(3):284–7. doi:10.4103/0972-124X.85677
15. Alani A, Maglad A, Nohl F. The prosthetic management of gingival aesthetics. Br Dent J. 2011;210(2):63–9. doi:10.1038/sj.bdj.2011.2
16. Ingber JS. Forced eruption. I. A method of treating isolated one and two wall infrabony osseous defects-rationale and case report. J Periodontol. 1974;45(4):199-206. doi:10.1902/jop.1974.45.4.199
17. Waerhaug J. Healing of the dento-epithelial junction following subgingival plaque control. II: As observed on extracted teeth. J Periodontol. 1978;49(3):119–34. doi:10.1902/jop.1978.49.3.119

ABOUT THE AUTHORS

Dr. Goldberg is a periodontist working in private practice in New Jersey. Dr. Goldberg received his DDS degree from Columbia University in 2018 and continued to complete his periodontal residency at Rutgers University in 2021. During his postgraduate tenure, Dr. Goldberg presented at and moderated the Northeastern Implant Symposium and served as chief resident, received a degree from the Institute of Advanced Laser Dentistry (IALD), and was awarded the Michael J. Deasy Endowed Scholarship. He currently practices with his father, an established periodontist as well. He can be reached via email at adamgoldberg2207@gmail.com.

Dr. Drew is a professor, director of implantology, and the vice chairman in the department of periodontics at the Rutgers School of Dental Medicine (RSDM). He received his doctorate and degree in periodontics from RSDM. He has been awarded the RSDM Excellence in Teaching Award, Stuart D. Cook Master Educators Guild Award, and the prestigious American Academy of Periodontology Educator Award. Dr. Drew was inducted into the American College of Dentists, and he was awarded the RSDM Alumni Association Decade (1980s) Award. He has been published more than 35 times and has lectured throughout the country. He was in full-time clinical practice for more than 25 years. He can be reached at drhjdrew@aol.com.

Dr. Athansios obtained her DMD degree and continued to complete her periodontal residency and masters in dental science at RSDM in 2023, where she was selected by the faculty committee for exceptional professionalism and ethics, granting her the “Professionalism Award.” In addition, she was also recognized for her volunteer work by the New Jersey Dental Association and was acknowledged with the “Give Kids a Smile Award.” During her postgraduate tenure, Dr. Athansios presented at Tri-school Symposium, served as chief resident, received a degree from the IALD, and was awarded the Michael J. Deasy Endowed Scholarship. Her passion toward the field is reflected when she mentors many students at the high school and college level who wish to pursue a career in dentistry. She is currently a periodontist working in private practice in New Jersey. She can be reached at vbbortnik@gmail.com.

Dr. Lavie is a graduate of UMDNJ-New Jersey Dental School (now RSDM), where he earned his DMD and MSD degrees and his Prosthodontics Specialty Certificate. Dr. Lavie maintains a private practice limited to prosthodontics in Chatham, NJ, and serves as a clinical instructor in postgraduate prosthodontics at RSDM. He can be reached via email at drlavie@gmail.com. 

Disclosure: The authors report no disclosures.