Accuracy of digital complete-arch, multi-implant scans made in the edentulous jaw with gingival movement simulation: An in vitro study

STATEMENT OF PROBLEM The use of computer-aided design and computer-aided manufacturing (CAD-CAM) technologies is widely established, with single restorations or short fixed partial dentures having similar accuracy when generated from digital scans or conventional impressions. However, research on complete-arch scanning of edentulous jaws is sparse. PURPOSE The purpose of this pilot in vitro study was to compare the accuracy of a digital scan with the conventional method in a workflow generating implant-supported complete-arch prostheses and to establish whether interference from flexible soft tissue segments affects accuracy. MATERIAL AND METHODS An edentulous maxillary master cast containing 6 angled implant analogs was used and digitized with mounted scan bodies by using a high-precision laboratory scanner. The master cast was then scanned 10 times with 4 different intraoral scanners: TRIOS 3 with a complete-arch scanning strategy (TRI1) or implant-scanning strategy (TRI2), TRIOS Color (TRC), CEREC Omnicam (CER), and CEREC Primescan (PS). The same procedure was repeated with 4 different levels of free gingiva (G0-G3). Ten conventional impressions were obtained. Differences in implant position and direction were evaluated at the implant shoulder as mean values for trueness and interquartile range (IQR) for precision. Statistical analysis was performed by using the Kruskal-Wallis and post hoc Conover tests (α=.05). RESULTS At G0, position deviations ranged from 34.8 μm (IQR 23.0 μm) (TRC) to 68.3 μm (12.2 μm) (CER). Direction deviations ranged from 0.34 degrees (IQR 0.18 degrees) (conventional) to 0.57 degrees (IQR 0.37 degrees) (TRI2). For digital systems, the position deviation ranged from 48.4 μm (IQR 5.9 μm) (PS) to 76.6 μm (IQR 8.1 μm) (TRC) at G1, from 36.3 μm (IQR 9.3 μm) (PS) to 79.9 μm (IQR 36.1 μm) (TRI1) at G2, and from 51.8 μm (IQR 14.3 μm) (PS) to 257.5 μm (IQR 106.3 μm) (TRC) at G3. The direction deviation ranged from 0.45 degrees (IQR 0.15 degrees) (CER) to 0.64 degrees (IQR 0.20 degrees) (TRC) at G1, from 0.38 degrees (IQR 0.05 degrees) (PS) to 0.925 degrees (IQR 0.09 degrees) (TRI) at G2, and from 0.44 degrees (IQR 0.07 degrees) (PS) to 1.634 degrees (IQR 1.08 degrees) (TRI) at G3. Statistical analysis revealed significant differences among the test groups for position (G0: P<.001; G1: P<.05; G2: P<.001; G3: P<.001) and direction (G0: P<.005; G1: P<.001; G2: P<.001; G3: P<.001). CONCLUSIONS Without soft tissue interference, the accuracy of certain digital scanning systems was comparable with that of the conventional impression technique. The amount of flexible soft tissue interference affected the accuracy of the digital scans

The effect of clinical education on optimizing self-care by dental students in Switzerland

Students, who may begin their dental education with sub-optimal oral self-care practices, are taught they should motivate patients to clean interdentally and reduce/stop smoking. To better understand their internalization of these concepts, students were surveyed at two distinct time points. Student cohorts from four Swiss universities were asked to complete an interdental cleaning/smoking habit questionnaire at the beginning of their pre-clinical education (n = 110) and again a year later, when beginning treatment of patients (n = 115). A local cohort (n = 28) was observed for comparison. All subjects participated voluntarily and anonymously. Interdental cleaning ≥ 3 times per week was performed by 48% first-year and 43% secondyear students in Basel, 60% and 76% in Bern, 60% and 70% in Geneva, 41% and 49% in Zurich, and 29% in the local cohort. Logistic regression using gender, class year and school as explanatory variables showed gender (p < 0.001) and school (p = 0.018) influenced cleaning frequency, with the odds being 3.16 [95% CI: 1.76, 5.67] times higher for females to perform interdental cleaning ≥ 3 times per week. Smoking was reported both years in numbers too low to analyze. Approximately 29% of the local cohort and 52% of the first-year students displayed an interdental cleaning frequency congruent with oral health recommendations. Adequate cleaning frequency increased for second-year students to 58%, which was not significant. Further study is needed to determine why more dental students do not themselves clean interdentally

Effect of Caries Infiltrant on Margin Integrity of Composite Fillings Placed Adjacent to Demineralised Primary Enamel

PURPOSE To investigate the influence of pretreating demineralised enamel with an infiltrant on the margin integrity of Class V like composite restorations on primary teeth bonded with different adhesives. MATERIALS AND METHODS Forty specimens from primary molars were demineralised and circular class-V-like cavities were prepared. The cavities were treated with a universal adhesive (Scotchbond Universal Adhesive, 3M Oral Care), applied either in self-etch (SE) or etch-and-rinse mode (ER) mode. In groups SE-I and ER-I, the demineralised margins were pretreated with a caries infiltrant (Icon, DMG) prior to adhesive application. The cavities were restored with a nanofilled composite material and thermocycled. Marginal integrity was evaluated using SEM, and the percentage of continuous margin was statistically analysed. RESULTS Specimens treated with the caries infiltrant followed by the adhesive showed similar marginal continuity as the adhesive alone. CONCLUSIONS Pretreatment of demineralised primary enamel with a caries infiltrant before applying a universal adhesive does not influence the marginal integrity of composite fillings

Clinical outcomes of all‐ceramic single crowns and fixed dental prostheses supported by ceramic implants: A systematic review and meta‐analyses

Objective: To analyze the clinical outcomes of all-ceramic single crowns (SCs) and fixed dental prostheses (FDPs) supported by ceramic implants. Materials and methods: Based on a focused question and customized PICO framework, electronic (Medline/EMBASE/Cochrane) and manual searches for studies reporting the clinical outcomes of all-ceramic SCs and FDPs supported by ceramic implants ≥12 months were performed. The primary outcomes were reconstruction survival and the chipping proportion. The secondary outcomes were implant survival, technical complications, and patient-related outcome measurements. Meta-analyses were performed after 1, 2, and 5 years using random-effect meta-analyses. Results: Eight of the 1,403 initially screened titles and 55 full texts were included. Five reported on monolithic lithium disilicate (LS2) SCs, one on veneered zirconia SCs, and two on veneered zirconia SCs and FDPs, which reported all on cement-retained reconstructions (mean observation: 12.0-61.0 months). Meta-analyses estimated a 5-year survival rate of 94% (95% confidence interval [CI]: 82%-100%) for overall implant survival. Reconstruction survival proportions after 5 years were: monolithic LS2, 100% (95%CI: 95%-100%); veneered zirconia SCs, 89% (95%CI: 62%-100%); and veneered zirconia FDPs 94% (95%CI: 81%-100%). The chipping proportion after 5 years was: monolithic LS2, 2% (95%CI: 0%-11%); veneered zirconia SCs, 38% (95%CI: 24%-54%); and veneered zirconia FDPs, 57% (95%CI: 38%-76%). Further outcomes were summarized descriptively. Conclusions: Due to the limited data available, only tendencies could be identified. All-ceramic reconstructions supported by ceramic implants demonstrated promising survival rates after mid-term observation. However, high chipping proportions of veneered zirconia SCs and, particularly, FDPs diminished the overall outcome. Monolithic LS2 demonstrated fewer clinical complications. Monolithic reconstructions could be a valid treatment option for ceramic implants. Keywords: ceramics; dental implants; implant-supported dental prosthesis; meta-analysis; survival analysis; systematic review; treatment outcome; zirconia

Efficacy and safety of P11-4 for the treatment of periodontal defects in dogs

Objectives: This study's aim was to investigate the safety and performance of a self-assembling peptide matrix (SAPM) P11-4 for the treatment of periodontal disease in a controlled pre-clinical study. Materials and methods: Acute buccal bony dehiscence defects (LxW: 5 × 3 mm) were surgically created on the distal root of four teeth on one mandible side of 7 beagle dogs followed by another identical surgery 8 weeks later on the contralateral side. SAPM P11-4 (with and without root conditioning with 24% EDTA (T1, T2)), Emdogain® (C) and a sham intervention (S) were randomly applied on the four defects at each time point. Four weeks after the second surgery and treatment, the animals were sacrificed, the mandibles measured by micro-computed tomography (µ-CT) and sections of the tissue were stained and evaluated histologically. Results: Clinically and histologically, no safety concerns or pathological issues due to the treatments were observed in any of the study groups at any time point. All groups showed overall similar results after 4 and 12 weeks of healing regarding new cementum, functionality of newly formed periodontal ligament and recovery of height and volume of the new alveolar bone and mineral density. Conclusion: A controlled clinical study in humans should be performed in a next step as no adverse effects or safety issues, which might affect clinical usage of the product, were observed. Clinical relevance: The synthetic SAPM P11-4 may offer an alternative to the animal-derived product Emdogain® in the future

Pyrogenic molecular markers: Linking PAH with BPCA analysis

Molecular characterization of pyrogenic organic matter (PyOM) is of great interest to understand the formation and behavior of these increasingly abundant materials in the environment. Two molecular marker methods have often been used to characterize and trace PyOM: polycyclic aromatic hydrocarbon (PAH) and benzenepolycarboxylic acid (BPCA) analysis. Since both methods target pyrogenic polycyclic compounds, we investigated the linkages between the two approaches using chars that were produced under controlled conditions. Rye and maize straws and their analogues charred at 300, 400 and 500 °C, respectively, were thus analyzed with both methods. Moreover, we also measured BPCAs directly on the lipid extracts, on which PAHs were analyzed, and on the respective extraction residues, too. Both methods revealed important features of the chars, in particular the increasing degree of aromatic condensation with increasing highest heating temperature (HTT). The overlap between the two methods was identified in the lipid fraction, where the proportion of benzenetricarboxylic acids (B3CAs) correlated with PAH abundance. The results confirmed the validity and complementarity of the two molecular marker methods, which will likely continue to play a crucial role in PyOM research due to the recent developments of compound-specific PAH and BPCA stable carbon (d¹³C) and radiocarbon (¹⁴C) isotope methods

Decoupled sedimentary records of combustion : causes and implications

Author Posting. © American Geophysical Union, [year]. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 43 (2016): 5098–5108, doi:10.1002/2016GL069253.Pyrogenic carbon (PyC) is a collective term for carbon-rich residues comprised of a continuum of products arising from biomass burning and fossil-fuel combustion. PyC is ubiquitous in the environment where it can be transported by wind and water before being deposited in aquatic sediments. We compare results from four different methods used to trace PyC that were applied to a high-temporal resolution sedimentary record in order to constrain changes in PyC concentrations and fluxes over the past ~250 years. We find markedly discordant records for different PyC tracers, particularly during the preindustrial age, implying different origins and modes of supply of sedimentary PyC. In addition to providing new insights into the composition of sedimentary combustion products, this study reveals that elucidation of past combustion processes and development of accurate budgets of PyC production and deposition on local to regional scales requires careful consideration of both source characteristics and transport processes.UZH; NSF Grant Numbers: OCE-9708478, CHE-00891722016-11-3

Final Posttreatment Occlusion in Patients With Unilateral Cleft Lip and Palate

Objective: To evaluate final posttreatment occlusion in patients with complete unilateral cleft lip and palate (cUCLP) by comparing (1) 3 treatment centers, (2) males and females, (3) cleft and noncleft sides, (4) right- and left-sided clefts, and (5) orthodontic treatment with/without orthognathic surgery (OS). Design: Retrospective cohort study. Patients: Blinded posttreatment dental casts of 56 patients (19.4 ± 1.4 years) with cUCLP from 3 centers in Switzerland. Main outcome measure: Occlusal assessment using the modified Huddart/Bodenham (MHB) index. Results: Our sample comprised 35 males and 21 females, 46 with left- and 10 with right-sided clefts, of which 32 had undergone OS. The final posttreatment occlusion showed a median MHB score of 0 (interquartile range: -1.0 to 2.0) in the total sample and did not seem to depend on treatment center, sex, or OS. The MHB scores for the anterior buccal and the buccal segments were more negative on the cleft than on the noncleft side (P = .002 and P = .006, respectively). When the cleft was on the left side, the MHB score tended to be more positive in the labial (P = .046) and anterior buccal segments (P = .034). Conclusions: This study shows a very satisfactory final posttreatment occlusion in patients with cUCLP. The more constricted buccal occlusion on the cleft side emphasizes the attention that should be given in correcting the more medially positioned lesser maxillary segment. The influence of cleft-sidedness should be analyzed further on a sample including more patients with right-sided clefts. Keywords: Treatment outcome; cleft lip and palate; crossbite; dental arch relationships; dental occlusion; final post-treatment; multicentre study

Microbial approaches for the assessment of toothpaste efficacy against oral species: A method comparison

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Efficacy and safety of P11-4 for the treatment of periodontal defects in dogs

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)Objectives: This study’s aim was to investigate the safety and performance of a self-assembling peptide matrix (SAPM) P11-4 for the treatment of periodontal disease in a controlled pre-clinical study. Materials and methods: Acute buccal bony dehiscence defects (LxW: 5 × 3 mm) were surgically created on the distal root of four teeth on one mandible side of 7 beagle dogs followed by another identical surgery 8 weeks later on the contralateral side. SAPM P11-4 (with and without root conditioning with 24% EDTA (T1, T2)), Emdogain® (C) and a sham intervention (S) were randomly applied on the four defects at each time point. Four weeks after the second surgery and treatment, the animals were sacrificed, the mandibles measured by micro-computed tomography (µ-CT) and sections of the tissue were stained and evaluated histologically. Results: Clinically and histologically, no safety concerns or pathological issues due to the treatments were observed in any of the study groups at any time point. All groups showed overall similar results after 4 and 12 weeks of healing regarding new cementum, functionality of newly formed periodontal ligament and recovery of height and volume of the new alveolar bone and mineral density. Conclusion: A controlled clinical study in humans should be performed in a next step as no adverse effects or safety issues, which might affect clinical usage of the product, were observed. Clinical relevance: The synthetic SAPM P11-4 may offer an alternative to the animal-derived product Emdogain® in the future