Objectives: The aim of this study was to systematically revise the state of art of the accuracy of digital and conventional impressions in clinical full-arch scenarios. Methods: Electronic and manual searches were conducted up to December 2024. Only trials comparing the accuracy of digital versus conventional impressions were selected by two independent reviewers. Accuracy was evaluated by analysing the fit of the prostheses obtained through conventional workflows and those obtained from digital workflows using intraoral scanners. Alternatively, accuracy was assessed by comparing the standard tessellation language data acquired from intraoral scanning with those obtained from scanning the physical model. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. Meta-analysis was conducted to pool the mean differences from the included studies, with heterogeneity tested by Cochran’s Q test and quantified by the I² index. Results: We included 9 relevant studies from a total of 2535 identified studies. The risk of bias was evaluated as low, and the main results of all the included articles reported similar accuracy between digital and conventional impressions. Random effects meta-analysis resulted in a pooled mean difference of 152.46 (95% C.I. = 76.46–228.46, p-value < 0.001, I² = 93.48%). Conclusions: In conclusion, the results of the present systematic review reveal contradictory findings regarding the accuracy of digital impressions. However, most studies analysing the clinical performance of prostheses obtained through digital impressions suggest that their accuracy falls within clinically acceptable thresholds. Future research should report comparable outcomes and focus attention on linear deviations, comparing differences between conventional and digital impressions not in absolute terms, but relative to the distance measured.

Bone defects are the main reason for aesthetic and functional disability, which negatively affect patient’s quality of life. Particularly, after tooth extraction, the bone of the alveolar process resorbs, limiting the optimal prosthetic implant placement. One of the major pathophysiological events in slowly- or non-healing tissues is a blood supply deficiency, followed by a significant decrease in cellular energy amount. The literature shows that photons at the red and infrared wavelengths can interact with specific photoacceptors located within the cell. Through this mechanism, photobiomodulation (PBM) can modify cellular metabolism, by increasing mitochondrial ATP production. Here, we present a review of the literature on the effect of PBM on bone healing, for the management of socket preservation. A search strategy was developed in line with the PRISMA statement. The PubMed and Scholar electronic databases were consulted to search for in vivo studies, with restrictions on the year (<50 years-old), language (English), bone socket preservation, and PBM. Following the search strategy, we identified 269 records, which became 14, after duplicates were removed and titles, abstract and inclusion-, exclusion-criteria were screened. Additional articles identified were 3. Therefore, 17 articles were included in the synthesis. We highlight the osteoblast–light interaction, and the in vivo therapeutic tool of PBM is discussed.

Background: bone tissue regeneration remains a current challenge. A growing body of evidence shows that mitochondrial dysfunction impairs osteogenesis and that this organelle may be the target for new therapeutic options. Current literature illustrates that red and near-infrared light can affect the key cellular pathways of all life forms through interactions with photoacceptors within the cells’ mitochondria. The current study aims to provide an understanding of the mechanisms by which photobiomodulation (PBM) by 900-nm wavelengths can induce in vitro molecular changes in pre-osteoblasts. Methods: The PubMed, Scopus, Cochrane, and Scholar databases were used. The manuscripts included in the narrative review were selected according to inclusion and exclusion criteria. The new experimental set-up was based on irradiation with a 980-nm laser and a hand-piece with a standard Gaussian and flat-top beam profile. MC3T3-E1 pre-osteoblasts were irradiated at 0.75, 0.45, and 0.20 W in continuous-wave emission mode for 60 s (spot-size 1 cm²) and allowed to generate a power density of 0.75, 0.45, and 0.20 W/cm² and a fluence of 45, 27, and 12 J/cm², respectively. The frequency of irradiation was once, three times (alternate days), or five times (every day) per week for two consecutive weeks. Differentiation, proliferation, and cell viability and their markers were investigated by immunoblotting, immunolabelling, fluorescein-FragELTM-DNA, Hoechst staining, and metabolic activity assays. Results and conclusions: The 980-nm wavelength can photobiomodulate the pre-osteoblasts, regulating their metabolic schedule. The cellular signal activated by 45 J/cm², 0.75 W and 0.75 W/cm² consist of the PI3K/Akt/Bcl-2 pathway; differentiation markers were not affected, nor do other parameters seem to stimulate the cells. Our previous and present data consistently support the window effect of 980 nm, which has also been described in extracted mitochondria, through activation of signalling PI3K/Akt/Bcl-2 and cyclin family, while the Wnt and Smads 2/3-β-catenin pathway was induced by 55 J/cm², 0.9 W and 0.9 W/cm².

David M. Kim, DDS, DMSc/Nicola De Angelis, DDS/Marcelo Camelo, DDS/Marc L. Nevins, DMD, MMSc/Peter Schupbach, PhD/Myron Nevins, DDS: The purpose of this study was to determine the clinical and histologic efficacy of the combination of alloplastic biphasic calcium phosphate composed of 30% hydroxyapatite and 70% β?tricalcium phosphate (Osteon II) and a cross-linked collagen membrane used to reconstruct an extraction socket with new bone formation. Twelve patients from two private dental practices requiring extraction of maxillary and mandibular nonmolar teeth (n = 30) received both Osteon II (0.5- to 1.0-mm particle size) and the collagen membrane. The primary healing intention group (group A, n = 12) received primary flap closure over the membrane, while in the secondary healing intention group (group B, n = 18), the membrane was left exposed. Early wound healing seemed to be slower in group B when compared to group A, but the difference was not noticeable after 4 weeks. Clinical reentry revealed that the dimensions of the ridge appeared to be maintained in both groups, and internal socket bone fill was evident. The grafted area appeared to be well vascularized, but clinically visible graft particles were noted in some cases. Light microscopic analysis revealed the formation of new bone directly apposing the surfaces of graft particles and bridging the space between them, indicating that the graft material behaved as an osteoconductive scaffold. The mean amount of vital bone in group A was 40.3% ? 7.8%, while the remaining graft was 6.0% ? 4.0%. The mean amount of vital bone in group B was 47.3% ? 11.3%, while the remaining graft was 18.0% ? 20.0%. The absence of primary flap closure did not affect the percentage of vital bone formation or residual graft. (Int J Periodontics Restorative Dent 2013;33:71?78. doi: 10.11607/prd.1463)