The Accuracy of Full-Arch Intraoral Optical Impressions (IOS): Clinical Pilot Study of the Influence of the Scan Strategy, Operator, and Intraoral Scanner.

PURPOSE: To investigate the influence of a novel scanning strategy-using two new intraoral scanner devices with different operators-on the full-arch scanning accuracy for a dentate maxilla. MATERIALS AND METHODS: Two scanning strategies, a test and a control strategy, were used to produce full-arch impressions of the dentate maxilla of a study patient. Two intraoral scanning (IOS) devices were used. Five expert operators performed a total of 40 scans. The scan time was recorded for each. A reference model was obtained from the patient's maxillary arch with an analog impression. The model was later scanned with a high-precision laboratory scanner to create a digital reference model (DRM). The scanning accuracy was analyzed with 3D-analysis software using a root mean square (RMS) calculation method, and qualitative analysis was executed using machine learning software. RESULTS: The mean RMS result for the test strategy was 82.8 ± 16 µm compared to 81.5 ± 16 µm for the control strategy. The mean RMS results were 84.7 ± 15 µm for Primescan (PS) and 79.6 ± 17 µm for 3Shape (3S). As such, the scanning strategies and IOS devices did not influence the scanning accuracy. Yet, a significant difference was found when the two strategies' scanning times were compared (P = .001), as well as the IOS devices (P = .001). The operator was found to have no influence on the scanning strategy. CONCLUSIONS: The accuracy of digital impressions is not influenced by different strategies, devices, or operators, in contrast with the scanning time, which is influenced by both strategies and devices.

Full arch rehabilitation after failure of implants and teeth supporting an extensive fixed dental prosthesis: a staged approach.

The present clinical report describes athe treatment strategy for transition from of full-arch restorations supported, either partially or fully supported by failing implants that need to be removed. More specifically the staged approach proposes a deferred treatment sequence in which the failing implants or teeth are not all replaced simultaneously. On the contrary according to this technique, some failing natural or artificial abutments are preserved momentarily in order to maintain the patient with a fixed provisional restoration at all times throughout the execution of treatment, from the surgical phases until delivery of the final restoration. The present clinical report describes the staged approach in detail, compares it to other treatment options and illustrates all phases of therapy with a clinical case.

Influence of Bone Anatomy on Implant Placement Procedures in Edentulous Arches of Elderly Individuals: A Cross-Sectional Study on Computed Tomography Images.

PURPOSE: To describe the prevalence of alveolar bone atrophy in edentulous arches of elderly individuals in relation to insertion of dental implants and the eventual need for bone grafting procedures. MATERIALS AND METHODS: Computed tomography scan files of 228 edentulous arches of elderly patients (ages 65 to 100 years) were evaluated in relation to implant placement. Six measurements per arch were taken on cross-sectional reconstructions. Bone atrophy categories were described, in relation to implant placement, for the anterior and posterior sections of the arches. Six bone sections per arch were evaluated and allocated to the predetermined categories. Prevalence of each type of atrophy was calculated. RESULTS: In the maxilla, only 5.0% of the patients showed a bone anatomy capable of receiving implants without any augmentation both in the posterior and anterior regions; 64.4% showed the need for major reconstruction in both areas. In the mandible, 17.3% of the patients did not require any augmentation in both regions; 9.4% were in need of major reconstruction in both areas. The anterior part of the arches could eventually be treated without any bone augmentation in 10.9% of the maxillae and 72.4% of the mandibles, while minor augmentation was needed in 16.8% of maxillae and 15.8% of mandibles. CONCLUSION: Most edentulous elderly patients show some degree of alveolar bone atrophy. It is often feasible to insert implants in the anterior mandible to support a restoration. In most maxillary cases, alveolar atrophy calls for augmentation procedures in both the anterior and posterior areas. In elderly individuals, the anterior maxilla often shows bone deficiency interfering with simple implant placement procedures, thus also limiting the use of tilted implants.

Discrepancy between patient satisfaction and biologic complication rate in patients rehabilitated with overdentures and not participating in a structured maintenance program after 7 to 12 years of loading.

PURPOSE: There is a lack of studies reporting long-term prevalence of peri-implant diseases in patients rehabilitated with overdentures and not receiving maintenance, which is a common situation. The aim of this cross-sectional study was to evaluate the patient satisfaction and rate of biologic complications in patients rehabilitated at least 7 years before with mandibular/maxillary overdentures, who for personal or economic reasons decided not to participate in a structured supportive maintenance program. MATERIALS AND METHODS: Each of the patients filled out a health and dental history and a visual analog scale (VAS)-based satisfaction questionnaire; additionally, the patients received a clinical examination and a panoramic radiograph. The prevalence of periimplant diseases and the patient satisfaction were reported. Moreover, presumed risk indicators of peri-implant diseases and implant loss were tested through univariate analyses and multivariate, time-adjusted, logistic regressions. RESULTS: A total of 52 patients who received 63 overdentures on 252 implants were included. The included patients showed a high degree of satisfaction (mean VAS = 6.3; SD: 2.1) and very low discomfort rates and would repeat the type of rehabilitation (mean VAS = 6.99; SD: 2.6). The prevalence of peri-implantitis was 30.8% at patient level and 19.4% at implant level, while 23.1% of patients experienced implant loss at any time. A clear tendency toward increased prevalence of biologic complications after the eighth year of loading was noted. In loading time-adjusted regression analyses, bone-level implants were associated with a higher prevalence of recession with no/minimal inflammation (OR = 3.37; 95% CI: 1.16 to 9.77; P = .025), while the maxillary arch was associated with both severe peri-implantitis (OR = 4.18; 95% CI: 1.03 to 16.97; P = .046) and implant loss (OR = 9.27; 95% CI: 3.41 to 25.14; P = .000). CONCLUSION: Despite high levels of satisfaction, patients rehabilitated with overdentures not participating in a structured supportive schedule show high rates of biologic complications. For this reason, they should be strongly motivated, at the time of prosthesis delivery, to participate in a structured maintenance program.