Implant dentistry has certainly become a mainstream treatment modality in our GP practices. It is imperative that the dentist become confident and competent in these procedures. Understanding vital anatomy is paramount. The position of the mandibular canal, mental foramen and maxillary sinuses should be carefully examined to prevent any negative results. I prefer to take a “tooth down,” approach in determining proper positioning on any implant. That is to say, I design the tooth replacement first to help in the surgical placement. This minimizes prosthetic complications and provides emergence profile and smile design. Visualizing the case finished prior to any intervention is an art that often comes with experience. However, today’s technology allows the practitioner to use CBCT diagnosis and treatment planning in three dimensions, with various software systems, to idealize the placement of our implants to maximize the final esthetic and functional result. Our highly engineered implant designs create a predictable and positive prognosis for long term function.
Modern implants can be used to replace a single tooth, multiple teeth or aid in support of removable or fixed full arch appliances. Determining the candidacy of our potential implant patients is dictated by the quality and quantity of available hard tissue and the overall health. Healing problems can be a contraindication to implant placement and should be thoroughly reviewed. Bone height and width are considered, but when there is lacking of hard tissue, more invasive grafting procedures can be considered.
When evaluating compromised and extensive reconstruction, the pre-operative exam requires a more detailed understanding of the clinical circumstances. Proper planning and precision placement is critical to our success and the satisfaction of our patients.
It is important to realize that there must be keratinized tissue on the facial aspect of all our implants. Failure to realize this may result in periodontal issues.
To help in our placement of implants in compromised areas, a CBCT scan PaX-i3D Green, (Vatech America Inc) is made of the edentulous site. Here we saw significant vertical bone loss near the mandibular canal.
Figure 1: A CBCt analysis allows the practitioner to evaluate vital anatomy and determine available bone for dental implant placement. this diagnostic tool provides a three dimensional evaluation. the saggital view is most helpful to determine implant positioning.
Figure 2
Figure 2:
Following a consultation with the doctors at 3DDX, the type of implant and position of the implant is determined. A surgical guide is then fabricated to duplicate this digital positioning to the oral cavity.
Figure 3
3: Bone loss is significant after long term tooth loss in the posterior mandible. interocclusal space is evaluated prior to any surgical intervention to ensure there is enough room for tooth replacement.
(Figure 1) The narrow crestal portion also presents some challenges to surgical placement too. Following a consultation with the doctors at 3DDX (Boston, MA) the type of implant and positon of the implants is determined (Figure 2) A surgical guide is then fabricated to duplicate this digital positioning to the oral cavity. Often times, the bone loss following tooth extraction is accompanied by the mucosal tissue following the bone, which results in a lack of attached keratinized tissue of the facial aspect of the edentulous site. (Figure 3).
Bone loss is significant after long term tooth loss in the posterior mandible.
Figure 4
4: the precise surgical guide is both hard tissue and tooth supported in this situation. the guide must be stable.
Interocclusal space is also evaluated prior to any surgical intervention to insure that there is indeed enough room for tooth replacement. The fabricated precise surgical guide is tried in. Note that it is both hard tissue and tooth supported in this situation. (Figure 4)
The mucogingival line, or the line connecting attached gingiva to mucosal tissue can be easily visualized by infiltrating the site. The mucosa will bubble up significantly.
Figure 5
5: infiltration with local anesthetic bubbles up the mucosal tissue to the mucogingival line. it is imperative that keratinized tissue be available on the facial aspect of the implant restoration. the lack of attached gingiva is apparent and will need to be addressed.
(Figure 5) It is important to realize that there must be keratinized tissue on the facial aspect of all our implants. Failure to realize this may result in periodontal issues that can affect eventual bone loss around the implant and often results in negative symptoms including food trapping and soreness to the site.
The mucosa, being flexible does not provide adequate protection on the facial aspect of the implant site. The lack of attached gingiva could lead to bacterial invagination and potential peri-implantitits. (1,2,3,4,5)
Following local anesthetic administration, a reflection of the tissue is made exposing the bone. The surgical guide was fabricated to rest on hard tissue and the remaining tooth structure. It is stabilized with a retention pin. To create the guide, CBCT DICOM files were electronically sent to 3DDX through their HIPAA compliant online portal 3DDX Connect, along with casts of her edentulous ridge and a bite relation, to create a three-dimensional reconstruction of the patient’s CT scan. Virtual planning software from 3DDX reveals the vital anatomy and the eventual positioning of the implants.
Figure 6
6: Using the stable surgical guide, the osteotomies are made through the guide with the Hahn guided surgical kit. We drill directly through the guide to the precise stops on each bur.
Figure 7
7: the Hahn dental implant has some unique properties that allow for initial stability in the hard tissue. the 1mm machined collar provides for periodontal soft tissue health.
Figure 8
8: Both dental implants are torqued to final seat through this surgical guide.
Figure 9
9: Because of the lack of available keritinzed tissue, cover screws are hand tightened into each implant and the incision sutured with Vicryl suture.
Figure 10
10: A post operative CCBt used for education purposes here indicate that the implant is precisely positioned in the available bone
Osteotomies for the Hahn dental implant system (Glidewell Lab, Irvine, CA) are completed through the surgical guides. (Figure 6) Specific guided surgical drills insure a proper and precise torquing of the implant into the prepared site. Figure 7 illustrates the prominent thread design of the Hahn implant, which allows for precise, straightforward placement. The body of this implant is tapered with buttress thread pattern which allows for good initial stability and minimizes resorption in all bone types. There are coronal microthreads which aid in the preservation of crestal bone. The surface of the implant is treated with resorbable blast media to promote osseointegration. The implant’s machined collar facilitates soft tissue maintenance, while its conical, internal hex connection provides a secure stable prosthetic seal. The Hahn guided kit is simple to use and the implant is threaded directly through the guide. (Figure8) Positioning of the implants is confirmed with conventional digital radiographs. Cover screws were threaded into the implants to allow for unerupted healing. I buried the implants because of the lack of attached gingiva on the facial aspect. (Figure 9) This problem will be addressed upon uncovering of the implants in 3 months. The post operative CBCT was done for education purposes and illustrates the final, precise position of the implants. (Figure 10)
Figure 11
11: After approximately 3 months of integration, we now have to address the lack of attached gingiva on the facial of the integrated dental implants. An Orban knife is used to carefully incise a band of attached gingiva approximately 2mm wide from the lingual portion of the crest facially.
After approximately three months of integration, I had to address the lack of attached gingiva on the facial aspect of the integrated dental implants. An Orban knife was used to carefully incise a band of attached gingiva approximately 2mm wide from the lingual portion of the crest facially. (Figure 11) The cover screws were removed and the implant stability evaluated.
Stability and the implant site needs to be appreciated prior to moving forward with bridge fabrication. The level of osseointegration can be determined using resonance frequency analysis. This is a non invasive method of determining the stability of our implants. Information is provided to the practitioner on the state of the implant-bone interface. The Penguin RFA (Glidewell Direct, Irvine, CA) was used here. A MulTipeg is threaded into the Hahn dental implant. This is simply a transducer that is attached to the implant and stimulated over a range of frequencies by electromagnetic waves.
Figure 12
Figure 13
12,13: Prior to any final impression of the implant body, a Penguin resonance Frequency Analysis is completed to make sure the implants are stable. reading values greater than 70 indicate a very stable implant with low micromobility that can withstand normal functional forces.
An implant stability quotient (ISQ) is give with a range from 1 (lowest stability) to 99 (highest stability). Values of 70 and above indicate a very stable implant that can withstand normal functional forces in the mouth. (Figures 12, 13)
Figure 14
14: The attached gingiva from the lingual aspect of the crest is repositioned facially around a taller healing abutment. the lingual tissue is not reflected nor sutured.
Figure 15
15: Attached gingiva is created on the facial aspect of the implants resulting in a healthier peri-implant condition.
Figure 14 illustrates how the attached gingiva from the lingual aspect of the crest was repositioned facially around a taller healing abutment following osseointegraton and uncovering the suture came from the facial aspect of the tissue and around the healing abutment. The lingual tissue was not reflected or sutured. (Figure 14) Attached gingiva is created on the facial aspect of the implants resulting in a healthier periimplant condition. (Figure 15)
Figure 16
Figure 17
16,17: The Bruxzir zirconia bridge is cemented over prepared abutments. A final digital radiograph checks the final position.
A final implant level impression is made using a medium and heavy body polyvinylsiloxane material (Kettenbach, Huntington Beach, CA). Figures 16 and 17 illustrated the final Bruxzir zirconia bridge cemented over the prepared abutments. (Glidewell Lab, Irvine, CA) and the final digital radiograph which checks the final seat of the bridge.
It is easy for us to see an edentulous space and consider a dental implant reconstruction. However, there are many factors that need to be considered to idealize the final functional and esthetic result. Bone anatomy needs to be considered, as well as the medical condition and healing ability of our patients. We need to visualize the entire case finished, before ever beginning.
Taking a tooth down approach to diagnosing will help us explain to the patient what the final result will be. Bone loss is a natural, physiologic response to losing teeth. This may create issues in the esthetic zone and the final crowns may appear longer into the gingiva. This needs to be determined pre-operatively. Bone grafting is a solution to excessive bone loss, but may slow down the restorative process or be cost prohibitive. Fabrication of a threeunit implant retained bridge provided the necessary function for our patient and allowed her to eliminate her removable appliance. This improved quality of life can be facilitated by the GP while becoming confident and competent in the surgical and prosthetic aspects of implant dentistry.
References:
(1) Lindhe, J., Berglundh, T. The interface between the mucos and the implant. Periodontal 2000. 1998; 17: 47-54
(2) Schrott AR, Jimenez, M. et al. Five year evaluation of keratinized mucosa on peri-implant soft tissue health and stability around implants supporting full arch mandibular fixed prostheses. Clin Oral Implants Res. 2009; 20: 1170-1177.
(3) Berglundh T., Lindhe, J. et al. The soft tissue barrier at implant and teeth. Clin Oral Implants Res. 1991; 2: 81-90
(4) Adibrand, M, Shahabuei, M. et al Sigbificance of the width of keratinized mucosa on the health status of the supporting tissue around implants supporting overdenturs. J. Oral Implant. 2009; 35:232-237.
(5) Warrer, K, Buser , D et al. Plaque induced periimplantitis in the presence or absence of keratinized mucosa. Clin Oral Implants Res. 1995; 6(3); 131-138
Dr. Timothy Kosinski is an Affiliated Adjunct Clinical Professor at the University of Detroit Mercy School of Dentistry is currently Associate Editor of the AGD journals. Dr. Kosinski received his DDS from the University of Detroit Mercy Dental School and his Mastership in Biochemistry from Wayne State University School of Medicine. He is a Diplomat of the American Board of Oral Implantology/ Implant Dentistry, the International Congress of Oral Implantologists and the American Society of Osseointegration. He is a Fellow of the American Academy of Implant Dentistry and received his Mastership in the Academy of General Dentistry. Dr. Kosinski has placed over 14,000 dental implants and published over 190 articles on the surgical and prosthetic phases of implant dentistry.
Dr. Stephanie Tilley is a graduate of the University Of Alabama School Of Dentistry, and has undergone extensive training to bring you and your family the highest level of care possible. Dr. Tilley is a native of Pensacola, FL and has been practicing dentistry in her hometown since 1998.
Dr. Tilley keeps up with the latest in dentistry by attending continuing education seminars on topics such as oral surgery, implants, veneers, periodontal disease, cosmetic procedures, and much more. Dr. Stephanie has also done extensive training at Las Vegas Institute and The Engel Institute with Dr. Timothy Kisonski and Dr. Todd Engel. She is a member of Academy of General Dentistry, American Dental Association, Florida Dental Association, Alabama Dental Association, Academy of Laser Dentistry, The International Congress of Oral Implantologists and the Academy of American Facial Esthetics.
