Francesco Valente, DDS* - Andrea Sbrenna, DDS**
*Private practice, Rome, Italy - Via Tommaso Salvini, 2/a - dott@valente.com
**Private practice, Perugia, Italy
Keywords: prospective clinical study, flapless surgery, dental implant, computer aided implantology, computed tomography
Abstract:
Two of the most notable trends in modern surgical specialties are minimally invasive surgery and the integration of computerized diagnostics and computer-guided surgery. In oral implantology these two trends are now mainstream in the form on one side of the so called flapless surgery and on the other side of the computer-aided implantology. Even tough flapless surgery can be performed in some cases without the aid of the computer and a computer-aided approach not always allows a flapless procedure, these two approaches can be often combined with great advantage. The advantages of a flapless compared to a flap procedure parallel - just to make an example - those of a laparoscopic abdominal surgery compared to a laparotomy. They are of great value both for the patient and for the clinician and can be summarized in reduced discomfort (no edema, no or very little pain, no bleeding, no functional limitations) and reduced treatment time. The reduction of treatment pain and discomfort is a critical issue in modern medicine: traditionally the medical community has focused the attention on the objective outcomes of a therapy neglecting the so-called subjective outcomes, like patient satisfaction and treatment side effects. This was obviously an error but fortunately now things are changing: there is an increasing attention to the subjective outcomes, that are now reported in an increasing number of studies. However- no matter how advantageous it is - flapless implant surgery remains a blind surgical technique, difficult to perform and prone to errors leading to potentially serious complications. It can be transformed in a relatively simple procedure thanks to the Computer-Aided-Implantology (CAI). This consists in a integrated treatment sequence of 3 steps:
1.. Computed Tomography.
2.. Digital three-dimensional CT-based surgical planning software.
3.. Stereolithographic oral appliances that exactly transfer the computerized planning to the surgical field.
Computed Tomography is generally performed by spiral CT. It is essential to include in the CT images a replica of the final prosthesis so to integrate the anatomical with the functional and aesthetic determinants. Such radiopaque diagnostic appliance is often referred to as scan prosthesis. There are now numerous CT-based software available for 3-D implant planning. The one shown in the present lecture is the SimPlant© software (Materialise, Leuven, Belgium) that uses the original DICOM (Digital Imaging and Communication in Medicine) CT data to produce axial, 3D, panoramic and cross-sectional images, all visible at the same time in four interactive windows in the computer screen. With this software the jaws can be seen from any viewpoint and the implants virtually placed according to the bone anatomy and prosthesis design. Once the planning is completed is sent via the Internet to the production centre where by using CAM technology (Computer Aided Manufacturing) custom drill guides (SurgiGuides©) are produced by a laser that polymerise liquid acrylic resin in layers (stereolithography). After resin polymerisation, stainless steel drill guide cylinders of different diameters are positioned along the planned implant axis. Once assembled the SurgiGuides are ready for the surgical treatment and sent to the dental office. The SurgiGuides provide a link between the digital plan and the actual surgery. Such drill guides renders obsolete the traditional mental transfer of the planning to the surgery and the mental navigation process that while giving a lot of freedom to the surgeon, just because of that increases variability and errors compared to the planning. Computer assisted surgery is an exciting field whose popularity is rapidly increasing among implantologists all over the world. However there are not universally accepted guidelines as to the indications of such computer-aided approach to oral implants. The purpose of this presentation is to show through a case series of 14 consecutive patients that the CAI flapless approach can be used with great advantage not only in good bone ideal cases, but also in so called complex cases, where bone dimensions are less then ideal, entailing the use of tilted implants or bone augmentation procedures. For each implant site the bone quality, the final insertion torque, the Resonance Frequency Analysis (RFA) in Implant Stability Quotient (ISQ) and the implant dimensions have been registered. Bone level has been measured at the surgery and at the 6 months follow up using the implant platform as reference. Probing Depth and Bleeding on Probing were also recorded at follow-up. Patient satisfaction was evaluated using a 100mm Visual Analog Scale questionnaires. For 9 patients follow-up CT have been prescribed with the patient consent. 56 implants have been inserted with this protocol and followed for at least 6 months and for a maximum of 24 months. The mean insertion torque was 35Ncm. The mean ISQ was 71,2 at insertion and at 75,6 at 6 months follow-up. All implants but one were integrated and functional at the 6 months follow up, giving an implant survival rate of 98,3%. The failed implant was the most distal implant inserted in bone quality 4 and immediately loaded in bruxist patient and this could explain the failure. Interestingly the implant had a baseline ISQ of 85. Regarding general satisfaction with the treatment the mean score on the VAS was 90 (range 62-100 ) and the mean score for pain and bleeding after the surgery were respectively 17 and 5. The analysis of the follow-up CT have shown good correspondence between the planned and the final fixtures position. The reduction of therapeutic or iatrogenic morbidity has always been a cornerstone of medical ethics. Minimally Invasive Implant Surgery reducing patient experience of pain and discomfort almost to zero strictly complies with the golden rule of “Primum Non Nocere” and should be utilized whenever possible. The Computer-Aided approach can afford a Minimally Invasive Surgical access in the majority of implant cases otherwise bounded to receive an open surgical procedure and for this reason has the potential of dramatically change the oral implant scenario.
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