Comparison of postoperative intraoral scan versus cone beam computerised tomography to measure accuracy of guided implant placement-A prospective clinical study.

OBJECTIVE: To evaluate the accuracy of implant placement with a digitally planned guided implant procedure. Two methods for identifying the actual postoperative positioning of the implants were compared: CBCT and IO scanning. MATERIAL AND METHODS: Twenty-eight implants with a sandblasted and acid-etched surface were placed in thirteen patients using tooth-supported surgical guides following a digital planning procedure. The implants were submerged for 12-15 weeks. New CBCT images were taken for identification of the implant position. After second stage surgery, scan bodies were mounted on the implants and scanned with an IO digital scanner. The recordings from the CBCT images and the IO scans were compared with respect to the identified positions of the implants. RESULTS: The study did not resolve any significant differences of the identified positioning of the implants as measured by CBCT or IO, except for the apical deviations at the coronal and apical points. The angular difference between CBCT and IO scanning at the coronal point was -0.011 (±0.6) degrees, whereas the 3D deviation was 0.03(±0.17) mm. The distal deviation between CBCT and IO scanning was 0.01(± 0.16) mm, and the vestibular deviation 0.033(± 0.16) mm and the apical deviation difference was 0.09(± 0.16) mm. The 3D deviation at the apical point was 0.04(± 0.22) mm. The distal deviation between CBCT and IO scanning was 0.06(± 0.19) mm, and the vestibular deviation 0.032(± 0.23) mm and the apical deviation difference was 0.09(± 0. 16) mm. CONCLUSION: The study demonstrated that accuracy measurements using IO scanning yields comparable results to those obtained by CBCT.

In Vivo Accuracy of Implant Placement Using a Full Digital Planning Modality and Stereolithographic Guides.

PURPOSE: The aim of this study was to investigate a guided implant surgery procedure performed without any manual processes, by assessing the in vivo results following a digital planning and placement of dental implants using surgical templates. MATERIALS AND METHODS: Eligible patients were screened and enrolled in this prospective clinical study. A cone beam computed tomography (CBCT) scan was acquired, and the remaining dentition and soft tissues were recorded by an intraoral scanner after enrollment. The CBCT data and intraoral scan were fused in the planning software. The prosthetic reconstructions were digitally designed by a prosthodontist, and the ideal position of the dental implants was determined. The surgical template was digitally designed based on this plan, and a guide design was exported and manufactured in a stereolithographic process. The entire surgical procedure was performed with the aid of the template. An intraoral scan was performed 10 days after stage-two surgery using scan bodies placed on the implants. Digital preoperative and postoperative models were compared, and the metric difference between the planned and achieved implant positions was calculated. RESULTS: Twenty-seven implants were placed in 20 patients using tooth-supported surgical templates after a digital planning procedure. No implants were lost during the study period. The mean lateral deviation measured at the coronal point was 1.05 mm (SD: 0.59; range: 2.74 to 0.36). The mean lateral deviation measured at the apical point was 1.63 mm (SD: 1.05; range: 5.16 to 0.56). The mean depth displacement was + 0.48 mm (SD: 0.50; range: 1.33 to -0.52). The mean angle deviation was 3.85 degrees (SD: 1.83; range: 8.6 to 1.25). CONCLUSION: A simplified full digital planning procedure yields results comparable to conventional guided implant surgery. The main deviation between the planned and achieved implant positions in this prospective clinical study was angular. More clinical studies are needed to verify the procedure further.

Clinical evaluation of CAD/CAM metal-ceramic posterior crowns fabricated from intraoral digital impressions.

PURPOSE: The aim of this in vivo study was to evaluate the accuracy of metal-ceramic crowns fabricated using computer-aided design/computer-assisted manufacturing (CAD/CAM) in conjunction with intraoral digital impressions. MATERIALS AND METHODS: Fifty patients in a general practice participated in the study. Patients were provided with crowns fabricated from digital impressions taken with an intraoral chairside scanner. Prior to crown insertion, the marginal integrity, esthetics, and occlusal and articulation contacts were evaluated using California Dental Association (CDA) criteria. The precementation space of the crowns was evaluated with the replica technique. RESULTS: No adjustments were needed for any of the interproximal contact points. Adjustments of occlusion and articulation contacts were needed in 20% of the restorations. Clinical evaluation of the marginal integrity showed satisfactory results according to the CDA criteria. The 50 silicone replicas showed a median precementation space of 46 µm at the marginal measurement location, 94 µm at the midaxial location, and 185 µm at the centro-occlusal location. CONCLUSIONS: The precementation spaces of the crowns were within the acceptable range for CAD/CAM restorations.

Marginal and internal fit of cobalt-chromium fixed dental prostheses generated from digital and conventional impressions.

Objectives. Digital impressions are increasingly used and have the potential to avoid the problem of inaccurate impressions. Only a few studies to verify the accuracy of digital impressions have been performed. The purpose of this study was to compare the marginal and internal fit of 3-unit tooth supported fixed dental prostheses (FDPs) fabricated from digital and conventional impressions. Methods. Ten FDPs were produced from digital impressions using the iTero system and 10 FDPs were produced using vinyl polysiloxane (VPS) impression material. A triple-scan protocol and CAD software were used for measuring and calculating discrepancies of the FDPs at 3 standard areas: mean internal discrepancy, absolute marginal gap, and cervical area discrepancy. The Mann-Whitney U test was used for analyzing the results. Results. For conventional and digital impressions, respectively, FDPs had an absolute marginal gap of 147 µ m and 142 µ m, cervical area discrepancy of 69 µ m and 44 µ m, and mean internal discrepancy of 117 µ m and 93 µ m. The differences were statistically significant in the cervical and internal areas (P < 0.001). Significance. The results indicated that the digital impression technique is more exact and can generate 3-unit FDPs with a significantly closer fit compared to the VPS technique.

Ethics of esthetic dentistry.

Patient demand for esthetics has increased globally, and often for reasons of patient self-esteem. However, important ethical issues encompass treatment for purely esthetic reasons. Also, perceptions of what is esthetic differ among patients and clinicians. Therefore, the aim of this article is to make suggestions regarding some of the issues surrounding the ethical, esthetic treatment of patients, as well as present three cases illustrating the different meanings of esthetic health to different people.