November 13, 2018
by Goth Siu, BHSc, D.M.D, M.S., Cert. Prostho., FRCD (C), FACP Mark Lin, B.Sc., D.D.S., M.Sc. (Prosthodontics), FRCD (C) Amy Yeung, D.D.S., M.Sc. (Perio), F.R.C.D. (C)
The following case presentation will illustrate an anterior maxillary reconstruction with the use of dental implants and fixed prosthodontics. Our patient (P.C.) presented to the office with the pre-existing dental treatment done over 10 years ago as illustrated in Figures 1 and 2. Due to a large diastema between 11 and 21, the previous practitioner placed a bridge from 11-x-21 with a mesiodens, resulting in three central incisors. The patient also had a high smile line with a gummy smile and teeth that were small. The patient’s chief complaint was a “loose bridge”. After examination, the 14-x-12 ceramo-metal bridge was debonded. 14 and 12 abutment teeth were over prepared but were found to be vital and restorable. A draining fistula was observed near the apical region of 21. Radiographs (Figs. 3-6) were taken and revealed previous endodontic treatments with severely widen canals and ill-fitting posts at 11 and 21. A chronic periapical lesion at 21 was observed radiographically and the patient reported pain on palapation and percussion. Comprehensive diagnostic records were gathered in order to formulate the treatment plan. Case presentation was conducted reviewing several treatment options with risks, benefits and alternatives of each treatment plan. The patient wished for fixed prosthetics to restore and replace his natural dentition in a predictable manner with a good long-term prognosis. He also desired to be maintained in fixed provisionals throughout treatment.
Pre-op intraoral view.
Pre-op periapical radiographs.
The definitive treatment plan was to extract 11 and 21, and place implant restorations at 13, 11, 21, 23 and restore 14, 12, 22, 24 with single crowns. The difficultly was to convert three centrals into two and keeping the patient in fixed provisionals while minimizing the chance of prosthetic complications throughout treatment. A CBCT was done to determine bone volume and quality at sites 13, 11, 21, 23 (Figs. 7-11). Since the patient had small teeth, a gummy smile and a need to increase ferrule for 12 and 22, it was determined that crown lengthening was warranted. 11,21, 13,23 implants could be placed more apically to allow for increased crown height. Prior to the start of treatment, an additive only diagnostic wax up was done from 15-25. An intraoral mock up was done to show the patient the proposed treatment of creating larger teeth and switching back to two central incisors (Fig. 12). This wax up was also used to create a surgical guide for the implant placement, as well as for the crown lengthening procedure.
CBCT plan – site 13.
CBCT plan – site 11.
CBCT plan – site 21.
CBCT plan – site 23.
The existing PFM restorations at 14-x-12, 11-x-21, 22-x-24 were removed and new build ups were placed. A direct bisacrylic provisional was fabricated replicating the existing teeth.
Utilizing this wax set up, a surgical guide was provided during the implant surgery to ensure that all implants were placed to support the final PROSTHETIC requirements. Aside from mesial and distal spacial accuracies required, the depth of platform of each anterior implant had to be precise to anticipate the alterations after clinical crown lengthening. The surgical phase was staged where tooth 21 was extracted with socket grafting while implants were surgically placed at the 13 and 23 positions using the surgical guide. After healing for approximately four months, tooth 11 was extracted with immediate implant placement with socket grafting and delayed stage implant placement to 21 site. All the maxillary anterior implants were uncovered three months later. All the dental implants were uncovered using a tissue punch approach and confirmation of successful osseousintegration. Appropriate width and heights of healing abutments were utilized at the second stage uncovering appointment whereby the prosthetic phase will begin.
After 13, 11, 21, 23 were uncovered, new provisionals was fabricated for 14-24 based on the diagnostic wax up with two centrals. The provisionals were used to tissue train the implant sites at 13, 11, 21, 23. After optimum soft tissue architecture was established, crown lengthening was done at 15, 14, 12, 22, 24, 25 to create more ideal soft tissue margin levels.
Radiograph of site 21 after extraction and grafting.
Radiograph of guide pin at site 13.
Radiograph of guide pin at site 23.
Radiograph of 13 implant placement
Radiograph of 23 implant placement.
Radiograph of guide pin at sites 11 and 21.
Radiograph of 11 and 21 implant placement.
Based on the desired gingival contour, a surgical guided was fabricated indicating the anticipated gingival margins of the restorations. An internal bevel incision was performed following the gingival contour of the surgical guide around teeth 15, 14, 12, 22, 24 and 25. The tissues around the implants of 13, 23, 11 and 21 were not disturbed. A mucoperiosteal flap was elevated around the indicated teeth to allow for osseous recontouring to provide a minimum of 3 mm supracrestal tissue attachment (previously known as biological width) from the osseous crest to the anticipated restoration margin. In addition, reduction and festooning of the buccal osseous structure around teeth 14, 15, 24, 25 was performed to ensure a more harmonious blending of the dental arch.
After six weeks of soft tissue healing, the provisionals were then relined to correct the new gingival levels at 14, 12, 22, 24 and adjusted based on aesthetics, phonetics, and function. (Figs. 20-21). After six weeks of soft tissue maturation, closed tray impression were placed (Figures 22-23) and PVS impression material was used to capture both implants and tooth preparations from 14-24. Individual screw-retained porcelain/zirconia implant restorations were fabricated for 13, 11, 21, 23 (Figs. 24-26). Subgingival contours of the final restorations followed those of the provisional restorations. Implant restorations were torqued in at 35N/cm.
Smile with provisionals.
Intraoral view of provisionals.
Radiographs of 13 and 11 impression copings.
Radiographs of 21 and 23 impression copings.
11 screw-retained implant crown.
Lithium disilicate single crowns at 14, 12, 22, 24 were etched, treated with Monobond Plus and bonded with transparent Multilink resin cement (Figs. 27-30). Canine guidance was established bilaterally and even protrusive contacts were developed on the centrals. At six months recall, both soft and hard tissue appeared to be stable. The soft tissue appeared to be more mature and the grafted bone appeared more integrated (Figs. 31-34).
Intraoral view of definitive restorations.
Smile with definitive restorations.
Radiographs of definitive restorations at site 13 and 11.
Radiographs of definitive restorations at site 21 and 23.
Intraoral view of definitive restorations at six months.
Radiographs of definitive restorations at site 11 and 21 at six months.
Before and after intraoral view.
Before and after smiles.
In complex anterior implant cases, thorough treatment planning by the prosthodontist or restorative dentist is vital and proper sequencing is also essential. The usage of wax-ups, mock-ups and surgical guide helps the patient and all specialists to visualize the final outcome. In a drastic case such as this one requiring many procedures, excellent communication between all parties involved is mandatory. OH
Oral Health welcomes this original article.
We would like to thank Yuzo Matsumura, RDT for his lab support in this case.
About the Authors
Dr. Goth Siu completed his Doctor of Dental Medicine degree at the University of Pennsylvania in Philadelphia. He then completed a specialty residency program in Prosthodontics at the University of Illinois at Chicago. Dr. Siu is board certified in Prosthodontics in Canada and the US, and is in private practice in Toronto.
Dr. Mark H. E. Lin graduated from the University of Detroit Mercy for his dental program. He then completed a one-year General Practice Residency program at the Miami Valley Hospital in Dayton, Ohio. He practiced general dentistry for 13 years and then returned to complete his post-graduate training in the specialty of prosthodontics at the University of Toronto. He maintains a full-time specialty practice as a prosthodontist at Dr. Mark Lin Prosthodontic Centre.
Dr. Amy Yeung is a board certified Periodontist with a special interest in periodontal plastic surgery and implant surgery. Dr. Amy Yeung received her dental degree from the University of Toronto and completed a hospital residency at the Mt. Sinai Hospital. Dr Yeung then went to complete a Graduate program in Periodontics at the University of Toronto. Her past research interests includes how metabolic diseases impact healing.
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