Restoring missing lateral incisors in narrow space
NobelActive® 3.0 restoring a young patient's missing lateral incisors
A hygienist at one of our referring offices recently sent her 19-year-old daughter for consultation on congenitally missing teeth 12 and 22 (FDI system).
After discussing with the patient the different treatment modalities such as resin-bonded fixed partial dentures (FPD), cantilevered FPDs, conventional full-coverage FPDs, and orthodontic space closure and canine recontouring, implant-supported treatment was selected to preserve the canine teeth in their natural location and avoid reshaping the sound adjacent teeth.
Congenitally missing lateral incisors, horizontal ridge defect at sites 12 and 22 (Siebert Class 1)
Clinical situation and treatment planning
The clinical exam showed the patient has an average smile line, and adequate bands of keratinized tissue at both sites. In CBCT examination, horizontal ridge defects were identified at both sites showing less than 4 mm of ridge width. The lack of development and eruption of a permanent lateral incisor often results in deficient osseous ridge volumes.
A recent study by Monje et al. has shown the importance of >1.5 mm of bone thickness facial to implants to prevent excessive physiologic bone remodeling and to resist pathologic peri-implantitis.1 To achieve adequate ridge volume in congenitally missing spaces, ridge augmentation is often required. Also, 2-3 mm of soft tissue thickness is important to avoid discoloration of the abutment, but also to maintain crestal stability and establish biologic width around the implant. 2
To obtain adequate ridge volumes for long-term implant stability and implant placement in a prosthetically driven location, we chose to perform ridge augmentation before implant placement.
Surgical and prosthetic procedures
A full-thickness flap was elevated from the distal of tooth 13 to the distal of tooth 23 with vertical releasing incisions. Cortical perforations were completed at sites 12 and 21. creos™ allo.gain (allograft) was condensed over both sites with a veneering layer of creos™ xenogain contoured over the allograft. Cytoplast™ RTM collagen membrane was stabilized over the grafts with titanium tacs and the primary closure was obtained.
Sites grafted with a combination of allograft and xenograft, protected with Cytoplast RTM collagen membrane with tac stabilization
Six months following ridge augmentation, NobelActive 3.0 implants were inserted in position 12, which was found to have adequate bone volume, and in position 21, which was deficient at the crest. We decided to perform a second graft at the defect site and to cover the implant for another six months.
Ridge dimensions before implant placement, x-ray of NobelActive 3.0 implant at placement, and grafting site 21 at the time of implant placement to create +1.5 mm of buccal bone thickness
After six months, both implants were uncovered and provisional engaging abutments hand-tightened to place. Custom-milled polymethyl methacrylate (PMMA) shell crowns were luted to the abutments with flowable composite and the subgingival contours were created extra-orally. The provisional crowns were hand-tightened to place.
PMMA shell crowns were fabricated and luted to provisional engaging abutments
Initial insertion of the provisional crowns resulted in a gingival margin located coronal. The provisional crowns were severely under-contoured and did not support the gingival margin in its proper location.
According to Su et al., critical contour is the most superficial area of the transgingival zone.3 The critical contour influences the gingival level and the zenith position. By bulking out the critical contour, apical migration of the margin is promoted. The provisional crowns were roughened with a diamond bur. SR connect (light-curing bonding agent) was applied to the roughened surface and ideal crown contours were obtained intra-orally with a flowable composite. The crowns were then removed and the transgingival portion of the crown was then merged with the new critical contour dimension using a flowable composite. They were highly polished and decontaminated to allow cell adhesion. The crowns were reinserted to the implants demonstrating significant improvement to the gingival architecture.
Under contoured crowns were prepared and retention divots were placed (A), flowable composite was used to contour crowns to appropriate symmetry and position (B) crowns were removed showing new/appropriate critical contour (C) subcritical contour was merged with new critical contour position (D)
Fig. A: Initial provisional crown delivery
Fig. B: Immediately following the delivery of newly contoured provisional crowns
Two months following provisional crown delivery, custom impression copings were fabricated and sent to the restorative dentist for final restorations.
Treatment outcomes
We were able to achieve natural gingival contours with an esthetically pleasing gingival margin location. The patient and her mother were pleased with the results.
Fig. A: Pre-op
Fig. B: 3 months following provisional delivery
Fig. C: 6 months following final crown delivery. Restorative dentist also performed composite bonding for teeth number 11 and 21
Figures D & E: X-ray showing stable peri-implant bone level at 1-year follow-up
Conclusions
Congenitally missing lateral incisors pose significant functional and esthetic challenges. Missing teeth 12 and 22 were replaced with implant restorations. Ridge augmentation provided the necessary bone volume for crestal stability, protection against future peri-implant disease and better ridge contours. Manipulating the peri-implant tissues with provisional crowns developed the proper emergence profile for esthetic harmony. Once the ideal gingival architecture has been achieved, it can then be reproduced in the final restoration using custom impression copings.
NobelActive 3.0 implant was used in this case, as
- The narrow diameter of the implant allowed us to utilize implant therapy in the restricted lateral incisor locations.
- The aggressive thread design of the NobelActive helps to provide the necessary insertion torque if immediate provisionalization is desired.
About the author
Dr. Mark Hagan is a periodontist at Kansas Perio and Dental implants in Wichita, Kansas. He graduated from dental school at Creighton University; completed a GPR residency at the Denver VA medical Center; practiced as a general dentist for 4 years before deciding to pursue periodontics; completed a periodontal residency at UMKC dental school. He is board-certified in periodontology and dental implant surgery.
References
- Monje A, Roccuzzo A, Buser D, et al. Influence of buccal bone wall thickness on the peri-implant hard and soft tissue dimensional changes: A systematic review. Clin Oral Implants Res. 2023 Mar;34(3):157-176
Read on Pubmed - Gomez-Meda R, Esquivel J, Blatz MB. The esthetic biological contour concept for implant restoration emergence profile design. J Esthet Restor Dent. 2021;33:173–184
Read on Pubmed - Su H, Gonzalez-Martin O, Weisgold A, et al. Considerations of implant abutment and crown contour: critical contour and subcritical contour. Int J Periodontics Restorative Dent. 2010 Aug;30(4):335-43
Read on Pubmed