28 minute read
Dental Implants: An Update on Guided Surgery for Full-Mouth Reconstruction
Rishi Jay Gupta, DDS, MD, MBA; Justin Young, DDS, MD; and Michael Lee, DMD, MS
ABSTRACT
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Background: This article describes the intricate steps and processes required to plan and execute dental rehabilitation utilizing guided implant surgery through case scenarios presented for dentate and edentulous patients.
Case description: With the advent and progress in digital technology in dentistry and oral and maxillofacial surgery, it is now possible to restore even the most complex cases to full function. Implant dentistry is a wellresearched and established treatment modality for replacing the dentition, and the various studies supporting the intricate steps and outcomes will be highlighted through showcasing various implant cases.
Practical implications: This article provides the necessary knowledge and insight for a dental practioner to understand the nuances and pitfalls in preparing for a guided surgical case.
Key words: Surgical guide, stereolithography (SLA), cone beam computed tomography (CBCT), dual scan protocol, mandibular reconstruction, additive manufacturing, 3D printing, 3D intraoral scanning, guided surgery
AUTHORS
Rishi Jay Gupta, DDS, MD, MBA, is the section chief, oral and maxillofacial surgery, dental service, at the San Francisco VA Health Care System. He is an assistant professor, department of oral and maxillofacial surgery, at the University of California, San Francisco and practices in a private practice. Dr. Gupta is a fellow of the American College of Surgeons.
Justin Young, DDS, MD, is an adjunct clinical instructor, department of oral and maxillofacial surgery, at the University of the Pacific, Arthur A. Dugoni School of Dentistry. He practices dental implantology and oral surgery at a private practice in San Francisco.
Michael Lee, DMD, MS, is a staff prosthodontist, dental service, at the San Francisco VA Health Care System. He practices prosthodontics at a private practice in San Francisco.
Conflict of Interest Disclosure for all authors: None reported.
Implant dentistry has significantly evolved over the past decades due to the advances in digital technology. Traditional methods used in the surgical planning of dental implants were laborintensive processes involving wax-up of teeth or duplication of the denture with fabrication of a radiographic guide that would eventually be converted to a surgical guide. The role of this analog or surgical guide is to serve as the communication tool to allow for the restorative dentist to convey their desired implant placement with the surgeon. Time spent fabricating the surgical guide may ultimately be wasted as the desired implant positioning proposed by the dentist could conflict with in vivo anatomical considerations. This results in the surgeon “freehanding” implant surgery to accommodate the desired restorative position while not violating the anatomic boundaries in an attempt to prevent aborting the procedure and revising the surgical plan.
Stereolithography-generated guided surgery has revolutionized the approach to planning and delivery of implant dentistry. [1] One of the main advantages of the stereolithography-generated guided surgery protocol addresses exactly these issues because both the restorative dentist and the surgeon have the opportunity to collaborate in the planning phase virtually and prior to the surgical date. The guided surgical protocol provides enhanced accuracy and predictability from the proposed virtual implant positioning to the actual surgical placement. Subsequently, this technique also allows the restorative and surgical teams to deliver a premade surgical guide, bone reduction guide and very accurate provisional prosthesis for same-day delivery.
The initial step in the workflow for both dentate and edentulous cases entails obtaining bite registration, clinical photographs, vertical dimension of occlusion, initial CBCT images and intraoral 3D scans of the dentition and soft tissue. CBCT technology reduces the overall radiation exposure or peak kilovoltage (kVp) to the patient while providing high-fidelity identification of the inferior alveolar nerve, maxillary sinuses and other structures of interest to the surgeon. [2] The Digital Imaging and Communications in Medicine (DICOM) images are obtained from the CBCT of the bony structures, which provide accurate assessment of osseous contours, such as the lingual concavity, muscular insertions and other irregularities consistent with advanced maxillary or mandibular atrophy, thereby allowing facile identification and classification of surgical pitfalls. Intraoral scanning permits the assessment of the soft tissues of the static nature, which are converted to Standard Tessellation Language (STL) files utilized by the stereolithographic computer-aided design (CAD) software. The data from the DICOM and STL files are then merged to create an accurate, real-time reproduction of the oral hard and soft tissues.
The critical component in generating the surgical guide is accurately merging the DICOM files obtained from the CBCT and the STL files obtained from the intraoral 3D scan. This allows the structures captured in the 3D scan, such as the gingiva or dentition, whether natural or as part of a removable prosthesis, to be superimposed onto the bony structures imaged by the CBCT. It is, however, possible to perform the workup and surgical plan for these cases in the absence of a 3D intraoral scanner by scanning the casts obtained from the polyvinyl siloxane (PVS) impressions. Once merged, the clinicians can then virtually plan the placement of the implants and fabricate the surgical guide and provisional prosthesis. After stereolithographic printing of the surgical guide, tooth-borne and tissueborne guides should be verified by its seating directly in the patient to confirm adequate positioning, stability and accuracy in order to prevent reversion to standard “freehand” protocol.
This article describes the intricate steps and processes required to plan and execute dental rehabilitation utilizing guided implant surgery through case scenarios and descriptions presented for dentate and edentulous patients.
Treatment Planning Considerations for Short-Span Edentulism
Aesthetics and implant positioning are critical when treatment planning shortspan edentulism. The following factors describe these considerations in the workup of implant treatment of partial edentulism.
Restorative space — A prosthetic tooth that replaces the natural dentition often requires more bulk of material than its natural counterpart. This space must be secured and accounted for during the treatment planning process.
White esthetic score (WES) [3] — The WES provides a measure of symmetry of the dentition when comparing against its natural counterpart in the anterior aesthetic zone. The WES evaluates tooth form, tooth volume, tooth color, texture and translucency.
Pink esthetic score (PES) [3,4] — Aesthetic evaluation of a restoration in the anterior zone must be accompanied by a thorough assessment of the soft tissue aesthetics using the PES. The PES evaluates the mesial papilla, distal papilla, alveolar process, soft tissue texture, soft tissue contour, soft tissue color and the level of soft tissue margin.
Teeth proportions — Mismatches between the desired tooth form and the existing dimension of the edentulous span may exist. Additional restorative or orthodontic treatment planning may be required to obtain ideal symmetry in the anterior aesthetic zone.
Proximal contact location — Location of the proximal contact and the associated influence on the predictability of papilla fill has been well documented by Tarnow et al. [5] Inadequate proximal contact dimensions in the posterior dentition can promote food impaction that can increase the odds of caries formation on the adjacent natural dentition. Modification of the adjacent proximal surfaces may be necessary to achieve proper proximal contacts. [6]
Lip mobility — Patients with high lip mobility and a high smile line add additional layers of complexity to the treatment plan. High scores in both the WES as well as the PES are necessary to achieve optimum aesthetic outcome. On the other hand, the PES score has less influence on the final aesthetic outcome of treatments involving patients with a low smile line. [4,7]
Adjacent bone level and length of edentulous span — Papilla height and soft tissue contour are heavily influenced by the presence of adjacent natural dentition and the bone that surrounds them. Blunting of the soft tissue and insufficient papilla fill can be expected from deficient adjacent bone level and consecutive edentulous spaces.
Soft tissue biotype — Thick gingival biotype allows for a more predictable retention of the original soft tissue contour. Thin, fragile soft tissue is more prone to recession and frequently requires augmentation to avoid asymmetry in the aesthetic zone. [7,8]
Depth of implant placement — Implant platform level must be placed 3 mm apical to the planned gingival zenith to allow for adequate “running room” for the emergence profile. [8] Shallow placement based purely on existing bone level alone may cause aesthetic compromise and create hygiene access issues for the prosthesis.
Workup Checklist for Tooth-Supported Stereolithography Guides
CBCT of the patient’s dentition must capture all the relevant anatomic areas including the anatomy of the existing teeth on the arch of interest. Cotton roll or bite tabs are used to separate any occlusal contacts during the scan.
Intraoral scan of the buccal cusp tip and the incisal edges of the patient’s residual dentition serve as the fiduciary points that allow for the merging of this 3D scan to the CBCT data. Digital wax-up can be completed and the implant position can be treatment planned according to the teeth positioning. Printing out the digital wax-up to do a mock-up using a putty index of the printed model is highly recommended for any treatment plan involving the anterior aesthetic zone.
When an intraoral scanner is not available, take a PVS impression of the arch planned for implant surgery. This impression is to be poured up twice to generate two casts. Alginate impression of the opposing arch, which must be poured immediately, and necessary records are obtained for the mounting of the casts. Subsequently, the first cast from the PVS is scanned and merged with the patient’s CBCT. The second cast from the PVS impression is mounted against the opposing cast and a wax-up of the planned implant site is done. This cast with the wax-up gets scanned and merged to the first cast. These three merged images allow for the overlaying of the bony anatomy, soft tissue anatomy and the desired teeth positions to allow for proper position of implants.
Clinical Presentation No. 1
A 71-year-old male presented to the clinic with the following chief concern: “You know, I’ve had this partial for a long time and it’s okay, but I want to ask about what can be done to maybe transition to something I don’t have to remove.” Social and medical histories were noncontributory ( FIGURES 1).
After examination of the patient and a thorough discussion of the treatment plan, a decision was made to follow a staged approach involving:
■ Atraumatic extraction of the root tips of teeth Nos. 6 and 7 followed by socket preservation and guided bone regeneration.
■ CBCT and workup for toothborne guided surgery protocol for the placement of implants for teeth Nos. 6 and 8. [3]
■ Provisionalization and soft tissue sculpting of teeth Nos. 6 and 8.
■ Custom impression to duplicate emergency profile and fabrication of a screw-retained metal ceramic fixed partial denture.
Patient underwent extraction of teeth Nos. 6 and 7 followed by onlay grafting of teeth in the 6, 7, 8 region. Patient’s existing removable partial denture (RPD) was used as the interim prosthesis ( FIGURES 2).
Six months after the extraction and bone augmentation procedure, a CBCT scan of the patient’s maxillary arch was taken and diagnostic impressions were made for the surgical workup for implants on-site for teeth Nos. 6 and 8 (FIGURES 3). The diagnostic cast, the wax- up and the CBCT imaging of the patient were merged together and the implant position was planned for the access holes to emerge through the cingulum of the planned teeth Nos. 6 and 8 ( FIGURES 4 ).
The patient’s implant surgery was carried out in two stages, and the provisional restoration was placed at the time of the second-stage surgery. The patient was followed up for the sculpting of the soft tissue and the final impression was made with custom impression copings that were copied from that of the provisional restoration ( FIGURES 5).
Custom shade match was done and a screw-retained metal ceramic restoration with metal lingual was chosen as the definitive prosthesis. The patient’s low smile line helped disguise the mild soft tissue architecture discrepancy in the area of teeth Nos. 6–8, and the patient finished the treatment happy with the final result. Patient continues to return for routine examination every six months ( FIGURES 6).
Clinical Presentation No. 2
A 66-year-old female presented for evaluation and potential implant-related treatment of a failing, long-span anterior bridge. Physical examination revealed moderately severe anterior maxillary atrophy with absent teeth Nos. 3, 4, 6–10 and 12. The existing dentition included teeth Nos. 2, 5, 11 and 13–15 which served as abutment teeth. The mandibular dentition was similarly restored with a full-arch fixed partial denture ( FIGURES 7).
Abutment dentition were failing due to parafunction and recurrent decay. The patient’s initial referral was for implant consultation to place implants at Nos. 5, 8, 9 and 12 for two implant bridges from Nos. 5–8 and then from Nos. 9–12. Medical history was significant for newly diagnosed Type 2 diabetes and hypothyroidism. This patient also had the advantage of a low smile line.
A CBCT scan was obtained to determine the amount of remaining viable bone in the anterior maxilla. This revealed a severely atrophic anterior maxillary ridge exhibiting a combined hard and soft tissue defect ( FIGURE 8 ).
A two-stage treatment plan was recommended. The first stage involved hard tissue augmentation with anterior maxillary block grafting followed by a healing interval. The second stage entailed guided surgery for anterior maxillary implant placement, interim prosthetic fabrication and subsequent titanium bar supported hybrid prosthesis.
Intraoperatively, the bridge was sectioned mesial to tooth No. 4 and distal to tooth No. 11, leaving a cantilevered pontic on this side. A CBCT and intraoral 3D scan were merged to fabricate an immediate provisional denture, allowing the patient to have an aesthetic and functional interim restoration ( FIGURE 9).
The patient underwent anterior maxillary bone graft ( FIGURE 10 ). However, unanticipated complications arose due to infection associated with tooth No. 5 (abutment), which seeded the subjacent block graft in the right maxilla causing partial membrane exposure ( FIGURE 11). As a result, the treatment plan was modified to include extraction of tooth No. 5 and another implant to be placed in the area just distal to the extraction site.
The finalized treatment including merged images with digitalized soft tissue wax-up and overlay ( FIGURES 12 and 13). Preoperative digital workflow was used to confirm that there was sufficient bone and contour, and implant placement was done virtually prior to phase II surgery ( FIGURE 14 ).
A bone reduction guide and surgical template were fabricated and milled. The bone reduction guide and surgical placement template were stabilized with replicable surgical pin placement ( FIGURES 15).
The implants were placed without complications and a reverse torque test was performed at the fourth month to confirm osseointegration of the implants. Open tray impression copings and Duralay material were used to fabricate a jig for a verified final impression ( FIGURE 16A). Master cast was verified for passive fit using the one-screw-test method. Digital design of the titanium bar was done by overlaying the scan of the master cast and the planned teeth positioning. The one screw test was performed to confirm passive fit of the titanium framework before the finalization process to incorporate the acrylic teeth onto the framework ( FIGURE 16B). Patient was satisfied with final aesthetics and function ( FIGURE 17).
Treatment Planning Considerations for Full Edentulism
Accurate diagnosis of the fully edentulous patient is crucial in the treatment planning process regardless of the number of implants and the choice of definitive restorative treatment modality. The following factors are common considerations to make in the workup process for the implant treatment of full edentulism.
Patient’s chief concern — Chief concern is an important factor to consider when treatment planning for implants. When a patient presents with the chief concern of “my denture is loose,” this concern must be further evaluated to identify whether the patient’s denture issues stem from retention, stability and/or support. A common error is to jump to the conclusion of a retention-related problem when our patients report “loose denture.” However, support and stability are more important functional factors in the success of the prosthesis. Patients with a greater need for augmentation of support and stability would certainly benefit from implants with more support and stability from the implants. [9–11]
Aesthetics — Measurement of the patient’s smile line and lip mobility must be assessed to make sure that we are able to hide the prosthetic junction. Check the patient’s smile as well as their maximum animation and determine if the patient displays any of the existing maxillary alveolar ridge. If visible, bone reduction may be needed to hide this prosthetic junction in the definitive fixed prosthesis. [12]
Lip support — Lip support can sometimes be obtained through proper restoration of the teeth positioning, but moderate to severe deficiencies of lip support are most predictably augmented with a removable prosthetic option with flanges (e.g., bar or locator overdenture type). [13]
Phonetics — Phonetics are largely influenced by tooth positioning and vertical dimension. When considering fixed implant prosthesis, air leakage through the intaglio of the prosthesis frequently contributes to air leakage issues. Though most patients can tolerate this for a chance at obtaining a fixed restoration, the patient’s ability to tolerate this air leakage must be tested with a provisional restoration or a conversion prosthesis. Inability to tolerate the air leakage with the provisional restoration can force the patient into an implant-assisted removable prosthesis. [14]
Finances — Different treatment modalities involving different prosthesis type or definitive prosthetic materials come with different cost obligations for the patient and this must be discussed prior to the start of any treatment. Treatment options involving denture teeth and processed acrylic (e.g., All-On-4 type fixed hybrid restorations) frequently need reservicing of the acrylic every five to six years. Retentive elements or attachments under removable prosthesis also come with maintenance needs for periodic evaluation and replacement. This cost burden and responsibility should be discussed with the patient prior to the start of treatment.
Restorative space requirements — All too often, this important factor (restorative space) is first assessed too late, following implant placement, when prosthodontic alternatives are limited. 15 Different options in the choice of definitive restorative material come with different minimum space requirements. Evaluation of restorative space and plans to create this space must be part of the surgical workup to decrease the risk of prosthetic complications ( FIGURE 18 ). [15–17]
New and well-fitting prosthesis with good adaptation of the denture ensures predictability of the workup in the acquisition of the scans, along with increased stability of the mucosa-borne guide ( FIGURE 19).
Many of the requirements listed above in the planning for a guided surgery workflow for edentulous arches can be accomplished by going through the process of a new denture fabrication. The new denture process not only ensures good adaptation against the underlying tissue but also allows for the clinician to figure out proper teeth positioning that allows for them to plan the implant locations based on the planned teeth positioning.
Ultimately, the goal is to establish the teeth positioning and the vertical dimension prior to surgery and maintain them as a constant as we transition our patients through to the implant-assisted definitive prosthesis. If a decision is made by the clinician to keep or retain the existing denture that the patient presents with, stringent and thorough assessment of the denture must be done prior to hard relining and proceeding through the dual scan protocol.
Dual Scan Protocol for Mucosa- Borne/Bone-Supported Guides
For patients presenting with complete edentulism, there are two general types of guides that can be fabricated: mucosaborne guides and bone-supported guides. The workup checklists for these two guides are similar if not identical.
Radiographic markers — Radiographic markers are available in sticker form for easy application to the prosthesis. If stickers are not an option, round bur holes with heated gutta percha packed into the divots also serve as effective fiduciary points for the dual scan protocol ( FIGURE 20 ).
Centric relation (CR) registration with radiolucent bite registration material — Most bite registration materials are quite radiopaque. However, more radiolucent bite registration materials exist in the market for use in the dual scan protocol.
Prosthesis/guide scan — A prosthesis with radiographic markers is placed into the CBCT machine alone for a prosthesis scan. Foundation material supporting the prosthesis during this scan must be at least more radiolucent than the prosthesis itself. Styrofoam blocks or foam blocks from lab return boxes tend to work well for this process ( FIGURE 21).
Patient scan — The prosthesis (or the duplicate) with radiographic markers is put in the patient’s mouth and the CR registration is made. While the patient holds this position, the patient’s CBCT image is taken ( FIGURE 22).
Why two scans? Rationale for the requirement of the prosthesis scan alone has to do with the fact that the radiation dose setting taken during the patient’s scan to obtain the 3D bony anatomy is too high to reveal any surface details of the prosthesis worn by the patient. A scan of the prosthesis alone at a lower exposure setting allows for the acquisition of the unobscured, 3D image of the prosthesis. Merging of these two individual scans is done through the alignment of the fiduciary markers on the planning software ( FIGURES 23).
Clinical Presentation No. 3
The patient presented with a referral for prosthodontic evaluation with the chief concern of “I want implants.” Follow-up questions and a discussion with the patient regarding his chief concern and his dental history revealed that the past dental procedures that had been provided for him, which consisted of a series of interim RPDs, failed to address his aesthetic and functional concerns. He additionally stated that he was unable to wear any of his previous prostheses for more than an hour due to the associated pain and discomfort ( FIGURE 24 ).
After the patient’s clinical evaluation, the following problem list was generated:
■ Caries, terminal dentition.
■ Severe combination syndrome.
■ Partial edentulism.
■ Lack of posterior stops.
■ Inappropriate teeth positioning.
■ History of unsuccessful removable prosthesis.
After careful discussion of the treatment plan, the patient decided on the treatment plan of maxillary complete denture opposing a mandibular fixed implant supported denture (All-On-4 hybrid). Due to the extreme extrusion of the patient’s remaining dentition, a staged approach was taken for the patient that involved the following sequence:
■ Extraction of remaining teeth, alveoloplasty and delivery of the maxillary immediate denture ( FIGURE 25).
■ Fabrication of the maxillary and mandibular denture after healing to determine ideal teeth positioning and correct vertical dimension of occlusion (VDO) ( FIGURE 26).
■ Dual scan protocol for the planning of four implants in the mandibular arch ( FIGURE 27).
■ Guided surgery for the placement of four implants and fabrication of a conversion prosthesis ( FIGURE 28 ).
■ Fabrication of mandibular fixed hybrid prosthesis with processed denture teeth.
A preliminary cast of the implant position was generated to allow for the fabrication of the verification jig. This verification jig was cut and reluted intraorally and the final impression was made using the additional silicone 23B impression material. Cast was poured in high-strength, low-expansion stone and the verification jig was retrieved from the impression material. The verification jig was sectioned and reluted again in the patient’s mouth; this reluted jig was used to verify the master cast. Subsequently, a jaw relations record was made in CR and a VDO that had been tested with the patient’s conversion prosthesis (made from the original denture). Casts were mounted and a putty index of the mandibular conversion prosthesis was used as the reference to duplicate the teeth setup of the conversion prosthesis. Mounted casts, putty index and the teeth setup were sent to the lab for the fabrication of the superstructure ( FIGURES 29 and 30).
A modified Montreal bar was chosen for the supporting superstructure, and this bar was tested on the master cast and intraorally for passive fit using the onescrew test. Passive fit was confirmed and the teeth setup was transferred onto the Montreal bar for another intraoral try-in. CR and VDO were checked and verified again and patient approval was obtained to proceed to the finalization. Finalized wax setup of the maxillary denture and the mandibular prosthesis were flasked and processed using heat-activated Lucitone 199 polymethylmethacrylate (PMMA).
Laboratory and clinical remount were completed, and the patient left satisfied with the maxillary complete denture and the mandibular fixed hybrid prosthesis. The patient subsequently returned for two adjustments at 24 hours and 72 hours followed by yearly recall for implant maintenance protocol ( FIGURES 31 and 32).
The importance of the yearly maintenance was emphasized, and the patient was reminded of the five- to six-year timeline for the wear of acrylic denture teeth that would likely involve reservicing of the prosthesis. The patient was satisfied with the overall outcome of the treatment plan.
Treatment Planning Considerations for Maxillofacial Reconstruction
Mandibular Reconstruction
Restoration of maxillary and mandibular defects is critical in restoring function, occlusion, facial aesthetics and airway. Maxillofacial reconstruction utilizing digital technology has evolved tremendously over the years. Traditional approaches entailed freehanding the bony reconstruction and placing dental implants as secondary procedure, [18] which led to inaccuracies, multiple surgeries with increasing morbidity and associated risks and prolonged time to definitive prosthodontic rehabilitation. [19–21] Virtual surgical planning (VSP) has allowed the surgical and prosthodontic teams to accurately plan the resection, autogenous bone harvesting and dental implant placement though the use of custom cutting guides, implant guides and reconstruction plates, which has led to improved success of the final prosthesis. [22–26] The multidisciplinary approach with the surgical and prosthodontic team is critical to deliver the best reconstructive outcome. [27, 28] The following case describes the intricate steps required to plan and execute jaw reconstruction with guided implant-supported prosthesis in a patient diagnosed with ameloblastoma.
Clinical Presentation No. 4
A 75-year-old man presented with an anterior mandibular biopsy-proven ameloblastoma. The patient reported a several-year history of expansile lesions with pain and malocclusion. A clinical exam showed a solid mass from canine to canine extending into the anterior floor of the mouth (FIGURE 33), mobility of teeth and a maximum incisal opening (MIO) of 45 mm. The patient was planned for segmental mandibulectomy with reconstruction utilizing fibula- and implant-supported prosthesis.
The preoperative CT head and neck ( FIGURE 34 ) scan and CT angiography of the right leg with upper and lower occlusal impressions with bite registration were sent to Stryker (Stryker, Kalamazoo, Mich.) for VSP. The case was a collaborative effort involving the oral and maxillofacial surgical, prosthodontic and otolaryngology and head and neck surgical teams at the San Francisco VA Health Care System. The first step entailed virtual surgical workup with superimposing of the scanned casts on the dentition in the CT scan. The planned resection was then completed to ensure a 1 cm margin. The right fibula was then segmented into four pieces for a doublebarreled reconstruction, and six Nobel implants (Nobel Biocare, Gothenburg, Sweden) were virtually positioned in the fibular segments to create the optimal prosthesis. Cutting guides for the mandibular resection and fibula harvesting with simultaneous implant placement and custom mandibular plates were designed (FIGURE 35).
Neuromonitoring equipment was placed to monitor the branches of the facial nerve. The tumor was approached through a neck incision and intraorally. The tumor was resected with the planned 1 cm margins and proper anatomic barriers utilizing the cutting guides. Upper and lower reconstruction plates were secured to the mandible with bicortical screws. Concurrently, the right fibula was accessed and a cutting guide was positioned ( FIGURE 36). Six dental implants, Nobel/ Replace Select 4.3 x 11.5, were drilled and secured in the predetermined sites through the surgical guide, the fibula was harvested, microvascular anastomosis was completed to the left facial artery and vein and the flap was inset to reconstruction plates in the anterior mandible.
The patient did well postoperatively. A panoramic image showed good adaptation of the fibular segments to the reconstruction plates and positioning of the dental implants ( FIGURE 37). The patient underwent a vestibuloplasty three months after the initial surgery to allow for more room for the final prosthesis ( FIGURE 38 ).
Additional soft tissue surgeries were performed on the patient at six months to reduce the soft tissue bulk overlying the implant sites. AlloDerm (BioHorizons, Birmingham, Ala.) was placed over the thinned areas and the provisional restoration was placed to guide the soft tissue healing ( FIGURE 39). The patient’s oral hygiene techniques were checked and revised to ensure the health of the peri- implant soft tissue. After confirmation of soft tissue stability, definitive restoration was fabricated with monolithic zirconia through the process of copy milling. The final prosthesis was delivered with good functional and cosmetic result ( FIGURE 40 ).
Conclusion
With the advent and progress of digital technology in dentistry and oral and maxillofacial surgery, it is now possible to restore even the most complex cases to full function, even under the most challenging circumstances. Implant dentistry is a well-researched and established treatment modality for replacing the dentition. CBCT and intraoral scanning provide for more precise and accurate planning for surgical placement of single and multiple implants, thereby elevating our standard of care. This technology also allows the practitioner to deliver prefabricated provisional restorations at the time of surgery to optimize aesthetic and gingival contour. Guided surgery permits minimally invasive surgery that improves the patient experience, but thorough understanding and troubleshooting of the protocols are vital to optimal outcomes. These nuances and pitfalls can be overcome through detailed preoperative planning and a collaborative approach. The predictability of implant placement and ease of prosthetic delivery due to guided implant surgery has placed it at the forefront of dentistry.
REFERENCES
1. Dandekeri SS, Sowmya MK, Bhandary S. Stereolithographic surgical template: A review. J Clin Diagn Res 2013 Sep;7(9):2093– 2095. doi: 10.7860/JCDR/2013/6052.3418.
2. Worthington P, Rubenstein J, Hatcher DC. The role of cone beam computed tomography in the planning and placement of implants. J Am Dent Assoc 2010 Oct;141 Suppl 3:19S–24S. doi: 10.14219/ jada.archive.2010.0358.
3. Belser UC, et al. Outcome evaluation of early placed maxillary anterior single-tooth implants using objective esthetic criteria: A cross-sectional, retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores. J Periodontol 2009 Jan;80(1):140–51. doi: 10.1902/jop.2009.080435.
4. Fürhauser R, et al. Evaluation of soft tissue around single-tooth implant crowns: The pink esthetic score. Clin Oral Implants Res 2005 Dec;16(6):639–44. doi: 10.1111/j.1600-0501.2005.01193.x.
5. Tarnow DP, Magner AW, Fletcher P. The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla. J Periodontol 1992 Dec;63(12):995–6. doi: 10.1902/jop.1992.63.12.995.
6. Gohil KS, Talim ST, Singh I. Proximal contacts in posterior teeth and factors influencing interproximal caries. J Prosthet Dent 1973 Sep;30(3):295–302. doi: 10.1016/0022-3913(73)90186-8.
7. Buser D, Martin W, Belser UC. Optimizing esthetics for implant restorations in the anterior maxilla: Anatomic and surgical considerations. Int J Oral Maxillofac Implants 2004;19 Suppl:43–61.
8. Buser D, et al. Early implant placement following singletooth extraction in the esthetic zone: Biologic rationale and surgical procedures. Int J Periodontics Restorative Dent 2008 Oct;28(5):441–51.
9. Jacobson TE, Krol AJ. A contemporary review of the factors i nvolved in complete denture retention, stability and support. Part I: Retention. J Prosthet Dent 1983 Jan;49(1):5–15. doi: 10.1016/0022-3913(83)90228-7.
10. Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete dentures. Part II: Stability. J Prosthet Dent 1983 Feb;49(2):165–72. doi: 10.1016/0022-3913(83)90494-8.
11. Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete dentures. Part III: Support. J Prosthet Dent 1983 Mar;49(3):306–13. doi: 10.1016/0022-3913(83)90267-6.
12. Bidra AS. Technique for systematic bone reduction for fixed implant-supported prosthesis in the edentulous maxilla. J Prosthet Dent 2015 Jun;113(6):520–3. doi: 10.1016/j. prosdent.2015.01.011. Epub 2015 Mar 24.
13. Bidra AS, Manzotti A, Wu R. Differences in lip support with and without labial flanges in a maxillary edentulous population. Part 2: Blinded subjective analysis. J Prosthodont 2018 Jan;27(1):17–21. doi: 10.1111/jopr.12621. Epub 2017 May 31.
14. Goodacre CJ, Kan JY, Rungcharassaeng K. Clinical complications of osseointegrated implants. J Prosthet Dent 1999 May;81(5):537–52. doi: 10.1016/s0022-3913(99)70208-8.
15. Ahuja S, Cagna DR. Defining available restorative space for implant overdentures. J Prosthet Dent 2010 Aug;104(2):133–6. doi: 10.1016/S0022-3913(10)60107-2.
16. Bidra AS. Surgical and prosthodontic consequences of inadequate treatment planning for fixed implant-supported prosthesis in the edentulous mandible. J Oral Maxillofac Surg 2010 Oct;68(10):2528–36. doi: 10.1016/j.joms.2010.05.054. Epub 2010 Jul 31.
17. Sadowsky SJ. Treatment considerations for maxillary implant overdentures: A systematic review. J Prosthet Dent 2007 Jun;97(6):340–8. doi: 10.1016/S0022-3913(07)60022-5.
18. Well MD. Part I. Mandibular reconstruction using vascularized bone grafts. J Oral Maxillofac Surg 1996 Jul;54(7):883–8. doi: 10.1016/s0278-2391(96)90542-x.
19. Roser SM, et al. The accuracy of virtual surgical planning in free fibula mandibular reconstruction: Comparison of planned and final results. J Oral Maxillofac Surg 2010 Nov;68(11):2824–32. doi: 10.1016/j.joms.2010.06.177. Epub 2010 Sep 9.
20. Pucci R, et al. Accuracy of virtual planned surgery versus conventional free-hand surgery for reconstruction of the mandible with osteocutaneous free flaps. Int J Oral Maxillofac Surg 2020 Sep;49(9):1153–1161. doi: 10.1016/j.ijom.2020.02.018. Epub 2020 Mar 18.
21. Chang EI, et al. Reconstruction of posterior mandibulectomy defects in the modern era of virtual planning and three-dimensional modeling. Plast Reconstr Surg 2019 Sep;144(3):453e–462e. doi: 10.1097/PRS.0000000000005954.
22. Levine JP, et al. Jaw in a day: Total maxillofacial reconstruction using digital technology. Plast Reconstr Surg 2013 Jun;131(6):1386–91. doi: 10.1097/PRS.0b013e31828bd8d0.
23. He Y, et al. Double-barrel fibula vascularized free flap with dental rehabilitation for mandibular reconstruction. J Oral Maxillofac Surg 2011 Oct;69(10):2663–9. doi: 10.1016/j. joms.2011.02.051. Epub 2011 Jul 1.
24. Wu YQ et al. Clinical outcome of dental implants placed in fibula-free flaps for orofacial reconstruction. Chin Med J (Engl) 2008 Oct 5;121(19):1861–5.
25. Chiapasco M, et al. Long-term outcome of dental implants placed in revascularized fibula free flaps used for the reconstruction of maxillo-mandibular defects due to extreme atrophy. Clin Oral Implants Res 2011 Jan;22(1):83–91. doi: 10.1111/j.1600- 0501.2010.01999.x. Epub 2010 Sep 27.
26. Chiapasco M, et al. Clinical outcome of dental implants placed in fibula-free flaps used for the reconstruction of maxillo-mandibular defects following ablation for tumors or osteoradionecrosis. Clin Oral Implants Res 2006 Apr;17(2):220–8. doi: 10.1111/j.1600-0501.2005.01212.x.
27. Sharaf B, et al. Importance of computer-aided design and manufacturing technology in the multidisciplinary approach to head and neck reconstruction. J Craniofac Surg 2010 Jul;21(4):1277–80. doi: 10.1097/SCS.0b013e3181e1b5d8.
28. Patel SY, Kim DD, Ghali GE. Maxillofacial reconstruction using vascularized fibula free flaps and endosseous implants. Oral Maxillofac Surg Clin North Am 2019 May;31(2):259– 284. doi: 10.1016/j.coms.2018.12.005. Epub 2019 Mar 5.
THE CORRESPONDING AUTHOR, Rishi Jay Gupta, DDS, MD, MBA, can be reached at rishijgupta@gmail.com.
