Panoramic images versus three-dimensional planning software for oral implant planning in atrophied posterior maxillary: a clinical radiological study.

PURPOSE: The objectives of this radiographic study were to determine to what degree the available residual bone area for implant placement was underestimated on panoramic radiographs (by comparison with multislice computed tomography CT/cone beam CT images combined with planning software) and to what degree the rate of severely resorbed posterior maxillae requiring sinus lift was overestimated on panoramic radiographs (by comparison with planning software in combination with strategic implant placement). MATERIALS AND METHODS: During a 2-year period, every patient who presented for the placement of implants in the posterior maxilla was examined by three practitioners to discuss the treatment plan. When two to three practitioners indicated a sinus lift with creation of a lateral window, a CT scan was performed and examined using dedicated three-dimensional software by a clinician familiar with the Computer Assisted Design/ Computer Assisted Manufacturing (CAD/CAM) implant placement protocol. For each tooth to be replaced, the presence of anatomical features such as anterior or posterior wall, palatal curvature, and septa were examined in view of the placement of an 8-mm or longer implant. RESULTS: One hundred one patients were studied in this case series for the treatment of 135 edentulous spans accounting for 301 missing teeth. After examination of the CT data on the three-dimensional software, 202 teeth (67.1%) could be replaced using a CAD/CAM procedure; 60.7% of the edentulous spans could be completely repaired by a crown or bridge supported by implants. In addition, 67.3% of edentulism with no teeth posterior to the span could be completely repaired using a fixed prosthesis supported by implants. CONCLUSION: This radiological study demonstrates that the use of a panoramic exam for oral implant planning in severely resorbed maxillae overestimates the need for a sinus augmentation procedure when compared with the use of both three-dimensional planning software and strategic implant placement on small remaining bone volume.

Flapless implant surgery using an image-guided system. A 1- to 4-year retrospective multicenter comparative clinical study.

PURPOSE: The aim of this retrospective multicenter clinical study was to compare the survival rate of dental implants placed with two different surgical procedures: (1) a flapless surgical procedure using an image-guided system (IGS flapless protocol) and (2) the conventional technique (open flap without IGS) with a computed tomography scan. MATERIALS AND METHODS: Between 2001 and 2004, 552 implants were placed in 169 patients by six practitioners who used both protocols to restore completely and partially edentulous arches: 271 of them were placed with the IGS flapless protocol (test group) and 281 with the conventional procedure (control group). Each implant was categorized as "survival" or "failure" after 1 to 4 years of follow-up after prosthesis implantation. A preoperative classification was used to evaluate the anatomic features of each case. There was initially no possible comparison between these two groups because of the indication bias relative to the retrospective clinical study data characteristics. After a classic logistic regression analysis, propensity scores were used to reduce this bias: prognosis variables were included in a regression logistic model to define the probability for each implant to be treated with the IGS flapless protocol. Implants showing the same probability were categorized into three classes. The implants were then compared with each other within the same class. RESULTS: After the follow-up period, the cumulative survival rate was 98.57% in the control group and 96.30% in the test group. Whatever the statistical method used, no statistical differences between the two protocols were shown. Transmucosal implant placement showed a survival rate of 97%. Even though the initial conditions were less favorable, the survival rate in the test group was comparable with the standard protocol group. CONCLUSION: Passing an implant through the gum does not interfere with osseointegration. The IGS flapless procedure makes it possible to use the flapless procedure, even though anatomic conditions were initially unfavorable.

Placement of posterior maxillary implants in partially edentulous patients with severe bone deficiency using CAD/CAM guidance to avoid sinus grafting: a clinical report of procedure.

PURPOSE: To provide a detailed presentation of computer-aided design/computer-assisted manufacture guidance in severely resorbed posterior maxillae to place implants in a very limited amount of bone, thus avoiding sinus grafting. MATERIALS AND METHODS: Based on computerized tomography (CT) axial images, implant positions are planned using imaging software. A surgical template is fabricated and drilled with a numerically controlled machine to transfer the planned positions to bone with high accuracy. To avoid sinus grafting, implants can be planned in the anterior or posterior wall and in the septa of the sinus as well as in the palatal curvature. Recipient site preparation is done transgingivally with a drill or with a dedicated bone spreader to increase the amount of bone when necessary. RESULTS: Fifteen resorbed posterior maxillae were treated with a fixed prosthesis supported by a combination of 42 upright and tilted implants. In all cases, implants were placed as planned. Seventeen implants were tilted at a 20- to 35-degree angle with the line perpendicular to the axial CT images. Seven implants were placed in the palatal curvature, 11 implants were close to the anterior wall, and two of them in combination with the palatal curvature. Only one implant was placed close to the posterior wall and two were placed in septa. All patients attended scheduled follow-up visits. During the 4-year observation period, no complications were recorded, no implants were lost, and there was no infection or inflammation. CONCLUSION: This proof-of-concept study suggests that the use of an image-guided system associated with bone spreading for oral implant placement in the atrophic posterior maxilla can be an alternative to sinus grafting.

Effect of flapless surgery on pain experienced in implant placement using an image-guided system.

PURPOSE: The aim of this study was to compare the pain experienced after implant placement with 2 different surgical procedures: a flapless surgical procedure using an image-guided system based on a template and an open-flap procedure. MATERIALS AND METHODS: The study population consisted of 60 patients who were referred for implant placement. One group consisted of 30 patients who were referred for the placement of 80 implants and treated with a flapless procedure. The other group consisted of 30 patients who were referred for the placement of 72 implants with a conventional procedure. Patients were selected randomly. They were requested to fill out a questionnaire using a visual analog scale (VAS) to assess the pain experienced and to indicate the number of analgesic tablets taken every postoperative day from the day of the surgery (DO) to 6 days after surgery (D6). RESULTS: The results showed a significant difference in pain measurements, with higher scores on the VAS with open-flap surgery (P < .01). Pain decreased faster with the flapless procedure (P = .05). The number of patients who felt no pain (VAS = 0) was higher with the flapless procedure (43% at DO versus 20%). With the flapless procedure, patients took fewer pain tablets (P = .03) and the number of tablets taken decreased faster (P = .04). DISCUSSION: Minimally invasive procedures may be requested by patients to reduce their anxiety and the pain experienced and thus increase the treatment acceptance rate. CONCLUSION: With the flapless procedure, patients experienced pain less intensely and for shorter periods of time.

An image-guided system-drilled surgical template and trephine guide pin to make treatment of completely edentulous patients easier: a clinical report on immediate loading.

PURPOSE: An image-guided system has been developed to drill a conventional surgical guide following a preoperative three-dimensional plan for accurate placement of implant on bone. The aim of this study is to illustrate how this system facilitates treatment of completely edentulous patients by modifying both surgical and prosthetic protocols, thereby making flapless surgery possible as well as the preparation of the transitional prosthesis before surgery. MATERIALS AND METHODS: This system was tested on 10 consecutive patients, placing all planned implants without raising the mucoperiosteal flap and with the connection of all implants to pre-angulated abutments. RESULTS: A 1-year follow-up demonstrated stable and properly functioning prostheses in all cases. CONCLUSIONS: This technique can be expected to flourish because implantology makes the highest demands on comfort, precision, and safety.

Reliability of preoperative planning of an image-guided system for oral implant placement based on 3-dimensional images: an in vivo study.

PURPOSE: The purpose of this study was to assess the reliability of the planning software of an image-guided implant placement system based on a mechanical device coupled with a template stabilized on soft tissue during surgery. MATERIALS AND METHODS: Thirty consecutive partially or completely edentulous patients were treated with the image-guided system. For each patient, a study prosthesis was fabricated and duplicated in acrylic resin and served as a scanning template. Axial images were obtained from a computerized tomographic scan and transferred to planning software that provides real 3-dimensional information to plan implant position. Once the final position of the implant was defined, preoperative data such as the size of implants and anatomic complications were recorded using the planning software. The scanning template was then drilled in that exact position by a drilling machine. During surgery, the drilled template was used as a drill guide. After implant placement, intraoperative data were recorded and statistically compared with the preoperative data using the Kendall correlation coefficient for qualitative data and the Kappa concordance coefficient for quantitative data. RESULTS: Agreement between the preoperative and intraoperative data was high for both implant size and anatomic complications. The Kendall correlation coefficient was 0.8 for the diameter and 0.82 for the length. The Kappa concordance coefficient was 0.87 for both dehiscence and bone graft, 0.88 for osteotomy, and 1.0 for fenestration. DISCUSSION: In the few instances where planning was not perfect, implant placement was completed in a clinically acceptable manner. CONCLUSION: The results suggest that the image-guided system presented is reliable for the preoperative assessment of implant size and anatomic complications. It may also be reliable for flapless surgery.