CT-Based Dental Imaging for Implant Planning

Source: N Y State Dent J. 2007 Jan;73(1):51-3. Almog DM, Romano PR.
CT-based dental imaging for implant planning and surgical guidance

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Introduction

There has been a rapid increase in the number of practitioners involved in implant placement.They include specialists and generalists,with different levels of expertise. When reviewing imaging modalities for preoperative assessment of the dental implant site,many conflicting variables need to be considered. The amount of information provided, its accuracy and its applicability need to be weighed against cost, convenience, availability, radiation dose and expertise required to produce and read the output of each modality.

Currently, there are a number of software systems that analyze CT scans to aid in planning the surgery and produce the physical surgical drilling template guides. These templates are computer manufactured in such a way that they perfectly match the planned implant location, trajectory and depth. They stabilize the drilling procedure while the dental practitioner placing the implants performs the procedure by restricting the degrees of freedom of the drill trajectory and depth.

The quantitative relationship between successful dental implant treatment outcomes and CT-based dental imaging, coupled with surgical template guidance, is unknown and awaits discovery through large prospective clinical trials. However, the concept of using CT-based dental imaging, coupled with surgical template guidance,has become evidence-based through review of recent preliminary clinical studies and case reports.

In this case report, the authors describe a systematic approach to the planning and surgical placement of a single, implant-supported crown in the maxillary second premolar region, using CT-based dental imaging for implant planning and surgical guidance. Because of the proximity of the implant site to the maxillary sinus and adjacent teeth, measures had to be taken when planning the implant trajectory to avoid damaging these structures. The simple steps described in this report resulted in the accurate transfer of critical radiographic trajectory information to the surgical site, avoiding the need for a maxillary sinus grafting procedure, while maintaining a safe distance from the adjacent teeth.

Conclusion

Outcomes assessment, including cost-to-benefit analysis, in this area of dentistry is difficult.However,the increased cost associated with CTbased imaging planning and computer-generated surgical guidance templates is justified from a consumer perspective. The correct placement of a dental implant is crucial for the fabrication of a functional and esthetic restoration. The restorative dentist must provide the surgeon with information for proper placement in three dimensions.

By incorporating the restorative planning during the preoperative assessment of the implant site by using a radiographic template with a radiopaque indicator in conjunction with a CT-based imaging system, the treatment was optimized from anatomical, restorative, functional and esthetic points of view. It allowed for a physical transfer of the implant planning to the patient’s mouth safely and predictably.

In the case described here, the final restoration was functional and esthetic, did not compromise adjacent teeth or anatomical structures, and was well accepted by the patient. This CT-based treatment planning protocol and surgical guidance template can be adopted for more complex case management.