Clinical Pearls: A JOMI review by AO's YCC
As an occasional feature of AO CONNECT, articles from The International Journal of Oral and Maxillofacial Implants (JOMI) — the official journal of AO— are reviewed from the viewpoint of a member of the Academy’s Young Clinicians Committee (YCC). Today’s “JOMI Clinical Pearls” by Dr. Nicole Olivares are pulled from Volume 32, Number 1, 2017.
By Nicole Olivares
A Clinical Study Assessing the Influence of Anodized Titanium and Zirconium Dioxide Abutments and Peri- implant Soft Tissue Thickness on the Optical Outcome of Implant-Supported Lithium Disilicate Single Crowns
(Francisco Martínez-Rus, DDS, PhD1/Marta Prieto, DDS2/María P. Salido, DDS, PhD3/Cristina Madrigal, DDS, PhD4/Mutlu Özcan, DDS, Dr Med Dent, PhD5/Guillermo Pradíes, DDS, PhD6)
This study sought to compare noticeable color differences in the gingival color around implants versus natural teeth using different abutment materials for anterior implants. They also compared the effect of peri-implant tissue thickness. Included patients needed a single implant in the maxilla in either the incisor, canine or premolar region. When the implant was ready for restoration, patients received custom abutments made of titanium, gold-anodized titanium, pink-anodized titanium, and zirconium dioxide. The facial and interproximal margins were placed at 1 mm subgingival, while the palatal margin was placed at the level of the gingiva. All abutment types were tried in each patient in random order. Each abutment was inserted for 10 minutes, the crown placed with try-in paste, and the color measured on the facial gingiva using an intraoral spectrophotometer, by a calibrated operator. The device took measurements 3 mm in diameter at the vestibular 3rd and 1 mm from the facial free gingival margin. Each measurement was performed 3 times. The experimenters measured soft tissue thickness and considered over 2 mm thickness to be thick and less than 2 mm to be thin. A noticeable color difference was seen with all abutment types as compared to natural teeth. Gold anodized titanium abutments and zirconia showed similar optical values in both thick and thin tissue. The greatest color difference was noted with titanium and pink- anodized titanium with thin tissue versus thick tissue.
Bottom line: The thicker the tissue, the more options you’ll have for abutments types. Consider tissue biotype when choosing abutment.
Long-Term Results of Peri-implant Conditions in Periodontally Compromised Patients Following Lateral Bone Augmentation
(Philip L. Keeve, DMD, MSc1/Fouad Khoury, DMD, PhD2)
This retroactive study compared the outcome of implants after at least five years of follow-up in patients treated for chronic periodontitis versus those placed in healthy patients. In both groups implants were placed in alveolar ridges which were augmented with split bone block techniques.
All patients received initial therapy, oral hygiene instruction and extraction of hopeless teeth. Periodontally compromised patients also received scaling and root planing and periodontal surgery as needed. Implant surgery was performed after residual pockets were less than 6 millimeters and full mouth plaque scores and full mouth bleeding scores(BOP) were less than 30%. After implant placement follow up including supportive periodontal treatment and recall based on periodontal risk assessment. Several parameters were measured including probe depth, bleeding on probing, peri-implant inflammation, gingival index, peri-implant recession and keratinized mucosa. Peri-implantitis was defined as comparison of radiographs, presence of BOP and or separation increase in more than 3 mm in probe depth, and progressive crestal bone loss over 3 mm. At the final examination bleeding on probing and mean gingival index was significantly higher for the periodontally compromised patients. Also noted was that implants with more than 2 millimeters with of keratinized mucosa.
Bottom line: Implants placed in ridges augmented with this particular split autogenous graft are successful in healthy patients and those with a history of periodontitis in a maintenance program. Keratinized tissue of at least 2 mm also appeared to be protective against periimplantitis.
Implant Placement Accuracy Using Dynamic Navigation
(Michael S. Block, DMD1/Robert W. Emery, DDS2/Kathryn Lank3/James Ryan, DDS, MS2)
Surgeons who place dental implants understand that a major factor in success is optimal implant placement. Several methods for implant placement are typically used: the free-handed approach, non-restrictive guidance using laboratory fabricated surgical guides and surgical guides made based on pretreatment Computerized tomography (CT). Of these three traditional approaches, CT generated stents with metal tubes which restrict the position of the implant drill, have been shown to be the most accurate. However this method has the disadvantage that it’s based on a previous scan of the patient, and therefore is static, and thus the surgeon is unable to make changes during while using the guide. Dynamic navigation is the use of a system which allows the surgeon to visualize implant placement in real time. A plan is made prior to surgery, however the desired implant position can be adjusted, and the guidance recalibrated during the procedure. This is done using special optical technology which uses special cameras and markers which are on the patient and the hand piece, allowing them to be oriented with fiduciary markers which the patient wears while the CT scan is taken.
During the procedure overhead cameras track the movement of the hand piece to the patient and display on a monitor the orientation to the predetermined implant site. This study evaluated 3 surgeons placing implants in the maxilla and mandible using this novel system. Only one of the surgeons had prior experience with Dynamic navigation the other two did not. In addition to comparing the accuracy of an dynamic navigation compared to the accuracy with traditional ridged guides, the study also evaluated the learning curve in use of this technology. They found that the accuracy of navigation system was similar to that reported for static CT generated guides, and better than free-handed implant placement. Furthermore after 20 cases performed using this technology there were minimal accuracy differences.
Bottom line: Dynamic navigation systems may allow for accurate implant placement compared to traditional CT generated ridged guides. They may have other advantages over the use of static CT generated guides, such as the ability to change the plan interoperatively and have access to the mouth that is not restricted by a bulky plastic stent. Care needs to be taken to reduce the learning curve and understand how to best teach clinicians to use these navigation systems.
About the Author
Dr. Nicole Olivares obtained her doctorate in dentistry from the University of California, Los Angeles. She went on to complete her specialty training in periodontics at Oregon Health and Science University. Dr. Olivares is a Diplomate of the American Board of Periodontology. She is in private practice in San Francisco, California with a focus on dental implants, periodontal plastic surgery and disease treatment.