Implants

Technology Expands the Scope of the General Practice

Daniel Drake, DDS February 28, 20179 Mins read3k Views

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INTRODUCTION
Modern dental technology has played a considerable role in empowering general dentists to offer superior treatment to their patients through the use of guided implant surgeries in their practice. Detailed computer processing of cone beam scans translated to precise fabrication of surgical guides has given the profession consistent and predictable implant surgical results without the potential guesswork of manual placement. Patients can feel comfortable knowing this protocol is less invasive, more efficient, and in many cases, results in less total treatment appointments. Let’s face it, the more we plan for an upcoming event, the more prepared we will be to succeed. Although it is important to note that guided surgery does not eliminate the need for relevant surgical training and digital treatment planning, the experienced comprehensive general dentist can use this technology in suitable case selections for the benefit of the patient.

CASE REPORT
Diagnosis and Treatment Planning
A 54-year-old female presented to our office as a previous patient who had been away for approximately 13 years. She requested a comprehensive evaluation, and her chief complaint was a severely unstable (obvious rocking) maxillary removable partial denture that she found difficult to wear in public and her missing anterior teeth Nos. 6 to 10 (Figures 1 to 4).


Figure 1. Patient before surgery with existing partial denture.	Figure 2. Edentulous anterior photograph.

Figure 3. Cone beam frontal view.	Figure 4. Axial view of maxilla.

Figure 5. Left side lateral view.	Figure 6. Right side lateral view.

The patient presented with several edentulous areas that were noted on her record when she had been a patient in the late 1990s. She had teeth Nos. 1, 6 to 10, 14 to 17, 31, and 32 extracted before originally becoming a patient in our practice, and she could not remember the exact dates of the extractions. She explained she had these teeth extracted in her native country of Suriname before she immigrated to the United States. The extractions were a result of a cultural ritual in which honey was used to coat the teeth. The continual application of honey, combined with improper oral hygiene, caused extensive caries and resulted in the loss of the teeth. She had removable partial dentures made to replace the missing maxillary teeth, with the most recent chromium cobalt base partial made in 2010 at another dental office. She had an asymptomatic, hypererupted right maxillary second molar due to the absence of the opposing molars. She had several composite restorations that appeared to be in good condition. She presented with a history of generalized slight chronic periodontitis that had been managed and maintained through initial traditional scaling and root planings and subsequent periodontal maintenance at 6-month recalls. Her current probing depths were 4.0 mm or less, except for 5.0 mm pockets on the mid-buccal and lingual of No. 3, and 6.0 mm pocket between teeth Nos. 11 and 12. No mobility or bleeding upon probing was evident during the periodontal examination. Periodontal scaling and root planing followed by Arestin placement for the pockets greater than 4.0 mm was recommended, then she would have a 4- to 6-week re-evaluation of pocket reduction and stability.

The patient had an unremarkable medical history with no prescription or over-the-counter drugs to report. Her overall systemic health was good. She was overweight with only a mild elevation in blood pressure, giving her an ASA II in the American Society of Anesthesiologists Physical Status classification.¹

The treatment goals were to determine the fixed and removable options that could meet the patient’s aesthetic desires, allowing for proper chewing and speaking. In addition, it would be important to restore the patient’s confidence for her busy family and work life.

Figure 7. Axial view of guided implant placement.

Several dental treatment options were presented to the patient to replace the missing maxillary anterior teeth and restore her occlusal function and aesthetics. However, as a preface to discussing her prosthodontic treatment options in our office, we discussed the relationship of her maxillary anterior to her mandibular anterior and their surgical and/or orthodontic realignment. Despite having a Class I occlusion, the patient exhibited an atrophic anterior maxilla relative to the mandible. In addition, she appeared to have significant mandibular anterior labial flaring of the teeth (Figures 5 and 6). The resorption of her anterior maxilla and loss of volume may have been, in part, due to the dental extractions and to the pressure from the intaglio surface of her removable partials throughout time.

Figure 8. Panoramic view of guided implant placement.

In order to provide a more natural overbite and overjet from a prosthodontic perspective, the patient would need the anterior maxilla augmented with block grafting or surgically advanced by a procedure such as a LeFort I osteotomy. However, the patient declined bone grafting or orthognathic surgery and wanted to know other treatment options that would not involve surgical reconstruction of the maxilla. We also discussed interproximal reduction of the mandibular teeth and use of brackets or Invisalign to move them lingually,² and the patient also declined this treatment.
The following options to replace teeth Nos. 6 to 10 were discussed along with their advantages and disadvantages.

Option 1—Forgo alternative dental treatment at this time and continue to use the metal-based maxillary removable partial denture currently worn to replace Nos. 6 to 10. Replacing the teeth and clasps may be necessary to alleviate the instability of the partial.

Option 2—Fabricate a new metal-based maxillary removable partial denture. Aesthetics could be improved with the right denture tooth shade selection and midline correction. Elimination of the rocking/lateral movement of the current partial could be achieved.

Option 3—Fabricate a maxillary fixed partial denture (FPD) using teeth Nos. 4, 5, 11, and 12 as the tooth abutments. The advantages of an FPD (bridge) would include immediate temporization of the maxillary anterior space and a final long-term restoration to be cemented 3 to 5 weeks later. However, masticatory efficiency could be affected by the long edentulous span of an FPD.³

Option 4—Surgical guided placement of 4 or 5 implants to allow for fabrication of implant-supported individual crowns or a splinted FPD. Advantages of implant therapy include avoidance of natural teeth as abutments and the durability of titanium.

Option 5—Surgical guided placement of implants with locators to support a metal-based partial overdenture. This option is generally preferred when custom abutments and implant crowns are too costly but the patient wants to enjoy the increased retention of the locators in his or her partial and avoid metal clasps in the smile-line.

The patient chose option 4, with the desire to have fixed cementable dentition in the maxillary anterior supported by dental implants.

A CBCT scan (Prexion) was taken to determine what implant sizes would maximize the maxillary osseous buccal lingual width. After examination of the CBCT scan, due to limited buccal lingual width, a surgical guided approach was discussed with the patient as a precautionary method to ensure that there would be ideal and specific placement of the implants.⁴ The cone beam DICOM and dental casts with bite registration were sent to nSequence (Reno, Nev) for fabrication of a surgical guide using the NobelGuide platform (Nobel Biocare).⁵ A GoToMeeting was set up to authorize location of digital implant placement. It was determined that 4 Nobel Tapered Replace Select (Nobel Biocare) implants would be used with different lengths and diameters (Figures 7 and 8).⁶ The surgical guide was fabricated and sent to us for verification of fit in the patient’s mouth and subsequent use in implant surgery.


Figure 9. Post-op right anterior at 8 weeks.	Figure 10. Post-op left anterior at 8 weeks.

Figure 11. Verification jig try-in.	Figure 12. Custom abutments on cast.

Figure 13. Custom abutments in patient’s mouth.	Figure 14. Wax try-in of prosthesis.

Figure 15. Final prosthesis before cementation.	Figure 16. After cementation, our very happy patient!

Surgical Phase
On the day of dental implant surgery, the patient was sedated using intravenous midazolam and meperidine. Her right and left maxillary anterior superior alveolar and greater palatine nerves were anesthetized using 3 carpules of 4% articaine and one carpule of 0.5% marcaine. The buccal and palatal soft tissue between the maxillary right first bicuspid and left canine was vertically released to allow for visualization of the crest.⁷ The surgical guide was placed and secured by her existing dentition. The customary drilling sequence using the Nobel surgical guide kit was followed until the appropriate osteotomies were created for loading of each specific implant. The surgical guide was removed, and each implant was tapped and torqued to 45 Ncm and a cover screw was placed for each implant.⁸ The soft-tissue flap was sutured to primary closure over the implants, and the patient was discharged with written postoperative instructions including the use of chlorhexidine twice daily for one week. The patient declined the postoperative prescription analgesics prior to sedation.

Healing Phase
The patient was reappointed for follow-up 48 hours later to evaluate the initial healing. Sutures were intact and clot formation was sufficient. Pressure-indicating paste was used to determine sore spots on her partial denture and was adjusted until the patient was comfortable with its seating. At 2 weeks postoperatively, healing of the soft tissue was sufficient to remove the sutures. The patient was seen again at 4 weeks and then radiographs were taken at 8 weeks (Figures 9 and 10). A diode laser was used for uncovering of the implant cover screws and removal with placement of 4 healing abutments.

Impressions
At 12-weeks post-surgery, the healing abutments were removed and the implants were torque tested to 35 Ncm. Osseointegration of all 4 implants was confirmed. Impression copings were placed on all 4 implants and an open-tray final impression was taken with a polyether impression material (Impregum [3M]).⁹ A lower impression and bite registration in centric occlusion (coincidental with her centric relation) was also taken to provide to the dental laboratory team.

Jig Verification
The lab team fabricated a verification jig to verify the correct positioning of the implants. The jig was finger tightened in the patient’s mouth (Figure 11) and radiographs of the coping interfaces were taken to confirm angulation and seating. Instructions were sent to the lab with the verification jig asking them to fabricate a substructure wax try-in for aesthetics to establish overjet and overbite.

Wax Try-In
The patient returned to our office, and the custom abutments were placed. Next, the substructure was tried in with the waxed teeth for the patient to approve (Figures 12 to 14). The patient approved of the aesthetics and end-to-end maxillary and mandibular occlusion. After choosing the shade, the substructure and custom abutments were sent back to the lab team for casting.

Cementation
At the cementation appointment, the custom abutments were placed into their respective implants and finger tightened. Radiographs were taken of each implant to verify complete seating at the abutment-implant interface. After verification, the screws were torqued to the manufacturer-recommended value of 35 Ncm. The splinted prosthesis was placed on the custom abutments to ensure proper seating. Following verification, the implant crowns were cemented using Durelon (3M). Durelon has been found to be excellent in semi-permanent retention in implant dentistry.¹⁰ An immediate postoperative retracted anterior photo was taken (Figure 15). The patient was appointed for a 12-week re-evaluation of the soft- and hard-tissue health and the occlusion.

Twelve-Week Reevaluation Appointment
At 12 weeks, the patient presented with no concerns (Figure 16). She was comfortable and very happy with her appearance and function.

CLOSING COMMENTS
Modern dentistry offers a myriad of options to replace missing teeth and restore function. These options can vary in terms of durability and aesthetics. Depending upon which option a patient selects, there may be limits to what a practitioner can achieve. Socioeconomic variables, physical anatomy, dental history, practitioner limitations, and/or procedure comfort levels may all affect treatment selection outcomes. However, if the patient satisfies the requirements for guided implant surgery, the experienced general dentist can have confidence in both surgically placing and restoring them. Under these circumstances, having the ability to control the implant experience from surgical start to restorative finish can deliver a superior result for the patient.

Acknowledgment
The author would like to thank the team at Esthetic Dental Lab (Palm Coast, Fla) for fabricating technically excellent custom abutments and the beautiful FPD; nSequence (Reno, Nev) for the accurate surgical guide; and his dental partner, Fred Costello, DDS, for his comprehensive dental knowledge, experience, and advice.

References

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