Auxiliary occlusal devices for IO scanning in a complete digital workflow of implant-supported crowns: a randomized controlled trial.

OBJECTIVES: To compare the crown accuracy and time efficiency of a complete digital workflow, utilizing an auxiliary occlusal device and IO scanning, with a conventional workflow, for multiple implant-supported single crowns. MATERIALS AND METHODS: 24 patients with two adjacent posterior implants were included. 12 patients were randomly assigned to digital workflow group, involving intra-oral scanning with an auxiliary occlusal device and manufacture of customized abutments and zirconia single crowns (test group). The other 12 were assigned to the conventional workflow (control group), involving conventional impression and CAD-CAM crowns based on stone casts. Crown scanning was done before and after clinical adjustment using an intraoral scanner. Two 3D digital models were overlapped to assess dimension changes. Chair-side and laboratory times for the entire workflow were recorded and a linear mixed model and Independent-sample t tests were used for the statistical analysis. RESULTS: The maximum occlusal deviation was 279.67 ± 112.17 µm and 479.59 ± 203.63 µm in the test and control group, respectively (p < 0.001). The sizes of the occlusion adjustment areas were 12.12 ± 10.51 mm2 and 25.12 ± 14.14 mm2 in the test and control groups, respectively (p = 0.013). The mean laboratory time was 46.08 ± 5.45 and 105.92 ± 6.10 min in the test and control groups, respectively (p < 0.001).The proximal contact adjustment and mean chair-side time showed no statistically significant difference between two groups. CONCLUSIONS: A digital workflow for two implants-supported single crowns using an auxiliary device required fewer occlusal crown adjustments, and less laboratory time compared to conventional workflow. CLINICAL RELEVANCE: The use of auxiliary occlusal devices in IOS enhances the accuracy of virtual maxillomandibular relationship in extended edentulous spans. Consequently, employing a digital workflow for multiple implants-supported crowns using IO scanning and an auxiliary occlusal device proves to be a feasible, accurate and efficient approach.

Digital registration versus cone-beam computed tomography for evaluating implant position: a prospective cohort study.

BACKGROUND: Postoperative cone-beam computed tomography (CBCT) examination is considered a reliable method for clinicians to assess the positions of implants. Nevertheless, CBCT has drawbacks involving radiation exposure and high costs. Moreover, the image quality can be affected by artifacts. Recently, some literature has mentioned a digital registration method (DRM) as an alternative to CBCT for evaluating implant positions. The aim of this clinical study was to verify the accuracy of the DRM compared to CBCT scans in postoperative implant positioning. MATERIALS AND METHODS: A total of 36 patients who received anterior maxillary implants were included in this clinical study, involving a total of 48 implants. The study included 24 patients in the single implant group and 12 patients in the dual implant group. The postoperative three-dimensional (3D) positions of implants were obtained using both CBCT and DRM. The DRM included three main steps. Firstly, the postoperative 3D data of the dentition and intraoral scan body (ISB) was obtained through the intraoral scan (IOS). Secondly, a virtual model named registration unit which comprised an implant replica and a matching ISB was created with the help of a lab scanner and reverse engineering software. Thirdly, by superimposing the registration unit and IOS data, the postoperative position of the implant was determined. The accuracy of DRM was evaluated by calculating the Root Mean Square (RMS) values after superimposing the implant positions obtained from DRM with those from postoperative CBCT. The accuracy of DRM was compared between the single implant group and the dual implant group using independent sample t-tests. The superimposition deviations of CBCT and IOS were also evaluated. RESULTS: The overall mean RMS was 0.29 ± 0.05 mm. The mean RMS was 0.30 ± 0.03 mm in the single implant group and 0.29 ± 0.06 mm in the dual implant group, with no significant difference (p = 0.27). The overall registration accuracy of the IOS and CBCT data ranged from 0.14 ± 0.05 mm to 0.21 ± 0.08 mm. CONCLUSION: In comparison with the 3D implant positions obtained by CBCT, the implant positions located by the DRM showed clinically acceptable deviation ranges. This method can be used in single and dual implant treatments to assess the implant positions.

Impact of scanning strategies on the accuracy of virtual interocclusal records in partially edentulous arch using intraoral scanner: an in vitro study.

PURPOSE: To evaluate the scanning strategies affecting the accuracy of virtual interocclusal records (VIR) in partially edentulous arches using an intraoral scanner in vitro. METHODS: A reference model of a partially edentulous arch with implant analogs in positions 45,46 and 47 was constructed. Six pairs of 1-mm diameter metal beads were placed on the gingival tissue as markers for measurement. Four scanning strategies were tested: Quadrant-arch Scan (group 1), Quadrant-arch Scan with Auxiliary occlusal devices (AOD) (group 2), Full-arch Scan (group 3), Full-arch Scan with AOD (group 4). The model was digitalized with a lab scanner as a reference and 15 scans were obtained for each group. The accuracy of VIR was assessed by comparing the experiment data to the reference digital model. RESULTS: The mean surface deviations of VIR for Groups 1-4 were 89.4 ± 105.2 µm,95.6 ± 132.8 µm,152.3 ± 159.7 µm and 107.6 ± 138.2 µm respectively. Quadrant-arch scans resulted in lower errors of VIR than full-arch scan (P < 0.001). There was a significant interaction between the AOD and scanning span (P = 0.017). The Quadrant-arch scan with AOD　(group 2) produced the least error in the distally extended edentulous area. CONCLUSIONS: Quadrant-arch scans showed better accuracy of VIR than full-arch scans across all tooth positions. The combination of AOD and quadrant-arch scan further enhances VIR accuracy in distally extended edentulous areas.

Crown adjustment and chairside efficiency of single-unit restorations fabricated from immediate and staged impressions using a digital workflow for posterior implants.

PURPOSE: This is a clinical study to compare immediate and staged impression methods in a complete digital workflow for single-unit implants in the posterior area. MATERIALS AND METHODS: Sixty patients requiring single-unit implant crowns were enrolled. Forty patients were assigned to the test group, immediate digital impression after implant surgery with crown delivery 4 months later. The remaining 20 patients were assigned to the control group, staged digital impressions 4 months after implant surgery, and crown delivery 1 month later. Both workflows involved free-model CAD-CAM crown fabrications. The crowns were scanned before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate the dimensional changes using Geomagic Control software. Chairside times for the entire workflow were recorded. Kruskal-Wallis was performed to compare crown adjustments between two groups, while One-way ANOVA was used to compare chairside time durations between the test and control groups. RESULTS: All crowns were delivered without refabrication. The average maximum occlusion adjustment of crowns was -353.2 ± 207.1 µm in the test group and -212.7 ± 150.5 µm in the control group (p = 0.02). The average area of occlusal adjustment, measured as an area of deviation larger than 100 µm, was 14.8 ± 15.3 and 8.4 ± 8.1 mm2 in the test and control groups, respectively (p = 0.056). There were no significant differences in the mesial and distal contact adjustment amounts, or the maximum deviations of the proximal area, between the two groups. The mean chair-side time was 50.25 ± 13.48 and 51.20 ± 5.34 min in the test and control groups, respectively (p = 0.763). CONCLUSIONS: The immediate impression method in the digital workflow for single-unit implants required more occlusal adjustments of crowns but showed similar chairside times compared to the staged impression method.

Impact of vertical alveoloplasty on changes in keratinized mucosa width following full-arch immediate implant placement and rehabilitations: A prospective case series.

PURPOSE: This prospective case series aimed to investigate the effect of vertical alveoloplasty on the changes in keratinized mucosa width (KMW) following full-arch immediate implant placement and rehabilitation. MATERIALS AND METHODS: A total of 17 potential edentulous patients were enrolled and received implant placement and full-arch implant-supported immediate rehabilitations. The main outcome was to analyze the effect of vertical alveoloplasty on the changes in KMW. The amount of vertical alveoloplasty during implant surgery as well as the changes in KMW at buccal aspects from the day of surgery to 6 months post-surgery were recorded on the implant-level using a periodontal probe. The secondary outcome was to analyze the other possible factors that affected the changes in KMW. The included factors were the initial KMW, the distribution of implants in the maxilla and mandible, the distribution of implants in the anterior and posterior regions, the distribution of implants in extraction sockets and healed ridges, and gender. Mann-Whitney non-parametric tests and multiple linear regression adjusted by generalized estimating equations (GEE) were used to statistically analyze the data. RESULTS: A total of 121 implant positions were analyzed. The KMW was 4.1± 2.0 mm on the day of the surgery and 4.1± 1.7 mm 6 months post-surgery. The mean changes in KMW following 6 months were -0.1± 1.6 mm (p = 0.824). From the results of GEE, the vertical amount of alveoloplasty had no significant effect on changes in KMW. Both initial KMW and the distribution of implants in the anterior and posterior regions had significant impacts on the changes in KMW (p < 0.0001). CONCLUSION: The amount of vertical alveoloplasty during implant surgery has no significant impact on the KMW. The KMW remained stable from baseline to 6 months after alveoloplasty, implant placement, and immediate rehabilitations in potential edentulous arches. The initial KMW and the distribution of implants in the anterior and posterior regions were the possible factors affecting changes in KMW.

Atomic-level engineering and imaging of polypeptoid crystal lattices.

Rational design of supramolecular nanomaterials fundamentally depends upon an atomic-level understanding of their structure and how it responds to chemical modifications. Here we studied a series of crystalline diblock copolypeptoids by a combination of sequence-controlled synthesis, cryogenic transmission electron microscopy, and molecular dynamics simulation. This family of amphiphilic polypeptoids formed free-floating 2-dimensional monolayer nanosheets, in which individual polymer chains and their relative orientations could be directly observed. Furthermore, bromine atom side-chain substituents in nanosheets were directly visualized by cryogenic transmission electron microscopy, revealing atomic details in position space inaccessible by conventional scattering techniques. While the polypeptoid backbone conformation was conserved across the set of molecules, the nanosheets exhibited different lattice packing geometries dependent on the aromatic side chain para substitutions. Peptoids are inherently achiral, yet we showed that sequences containing an asymmetric aromatic substitution pattern pack with alternating rows adopting opposite backbone chiralities. These atomic-level insights into peptoid nanosheet crystal structure provide guidance for the future design of bioinspired nanomaterials with more precisely controlled structures and properties.

Accuracy of impressions for multiple implants: A comparative study of digital and conventional techniques.

STATEMENT OF PROBLEM: Intraoral scanning has benefits over conventional impression making, but whether scanning is sufficiently accurate for multiple implants is unclear. PURPOSE: The purpose of this in vitro study was to compare the trueness of digital scans acquired by using intraoral scanners from a small range to a complete arch with the conventional impression technique and to determine the influence of 2 different evaluation methods (best-fit algorithm versus absolute linear deviation) on the outcomes of accuracy assessment. MATERIAL AND METHODS: A mandibular model with 8 implants (A-H) around an edentulous arch was used as the master model. Open-format standard tessellation language (STL) data sets (1 reference file from a highly accurate dental laboratory scanner, 10 files from an intraoral scanner, and 10 files from digitized conventional impressions at room temperature) were imported to a metrology software program, and 5 groups of scanning ranges (AB, FGH, CDEF, BCDEFG, and ABCDEFGH) were identified simulating different clinical situations. Two evaluation methods-root mean square values calculated from the best-fit algorithm and average value of linear discrepancies from absolute linear deviation-were used to describe the trueness values. The impacts of different scanning or impression methods, ranges, and evaluation methods were tested by using a 3-way ANOVA. The effect of the scanning range on accuracy was further identified with 1-way ANOVA. The paired-sample t test was used to determine the differences of trueness values between the 2 methods in different groups. RESULTS: The trueness values of the implant impressions were significantly affected by different scanning or impression methods (P<.001), evaluation methods (P<.001), and scanning ranges (P<.001) as independent variables. With use of the best-fit algorithm, deviations from the digital scans were significantly greater than those from the conventional impressions in cross-arch situations (groups CDEF, BCDEFG, and ABCDEFGH). With use of the absolute linear deviation method, statistically significant lower accuracy was found when larger areas were encountered (groups BCDEFG and ABCDEFGH). Use of the absolute linear deviation method resulted in a higher mean score of inaccuracy than that from the best-fit algorithm method in most situations. CONCLUSIONS: Scanning or impression methods, ranges, and evaluation methods affected the dimensional accuracy (trueness) of scans or impressions with multiple implants. Digital scans had worse trueness values compared with those made with the conventional splinting open-tray technique when cross-arch implant impressions were acquired.

Crown Accuracy and Time Efficiency of Cement-Retained Implant-Supported Restorations in a Complete Digital Workflow: A Randomized Control Trial.

PURPOSE: This is a clinical study to compare complete digital workflows generated using intraoral scanning and the split-file technique with a conventional workflow for cement-retained implant-supported restorations. MATERIALS AND METHODS: Forty patients requiring posterior single-unit implant restorations were included. Twenty patients were randomly assigned to the complete digital workflow group, involving intraoral scanning and manufacture of cement-retained crowns using the split-file technique (test group). The remaining 20 patients were assigned to the hybrid workflow group (control group), involving conventional impressions and CAD-CAM fabricated crowns based on stone casts. Scanning of the crowns was performed before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate changes in dimensions using Geomagic Control 2014 software. Chair-side and laboratory times for the entire workflow were recorded. Independent-sample t tests were used for the statistical analysis. RESULTS: All crowns were inserted without refabrication. The average maximum occlusal adjustment of the crowns, measured as maximum deviation of occlusal area in superimposed pre and post scans, was -212.7 ± 150.5 and -330.7 ± 192.5 µm in the test and control groups, respectively (p = 0.037). The average area of occlusal adjustment, measured as area of deviation larger than 100 µm, was 8.4 ± 8.1 and 17.1 ± 12.3 mm2 in the test and control groups, respectively (p = 0.012). The mesial and distal contact adjustment amounts, maximum deviations of proximal area, were -33.0 ± 96.2 and -48.6 ± 70.5 µm in the test group, and -3.7 ± 66.7 µm and -11.4 ± 106.7 µm in the control group, respectively. The mean chair-side time was 20.20 ± 3.00 and 26.65 ± 4.53 minutes in the test and control groups, respectively (p < 0.001). The mean laboratory time was 43.70 ± 5.56 and 84.55 ± 5.81 minutes in the test and control groups, respectively (p < 0.001). CONCLUSIONS: Single-unit cement-retained crowns with complete digital workflows required fewer crown adjustments and had shorter clinical and laboratory times compared to conventional impressions and hybrid workflows. Digital impressions and the split-file technique provided customized abutments and cement-retained crowns, thus broadening the indications for digital workflows for implants.

Epidemiology and HBGA-susceptibility investigation of a G9P[8] rotavirus outbreak in a school in Lechang, China.

Rotaviruses cause severe gastroenteritis in infants, in which the viruses interact with human histo-blood group antigens (HBGAs) as attachment and host susceptibility factors. While gastroenteritis outbreaks caused by rotaviruses are uncommon in adolescents, we reported here one that occurred in a middle school in China. Rectal swabs and saliva samples were collected from symptomatic and asymptomatic students, and samples were also collected from the environment. Using PCR, followed by DNA sequencing, a single G9P[8] rotavirus strain was identified as the causative agent. The attack rate of the outbreak was 13.5% for boarders, which was significantly higher than that of day students (1.8%). Person-to-person transmission was the most plausible transmission mode. The HBGA phenotypes of the individuals in the study were determined by enzyme immunoassay, using saliva samples, while recombinant VP8* protein of the causative rotavirus strain was produced for HBGA binding assays to evaluate the host susceptibility. Our data showed that secretor individuals had a significantly higher risk of infection than nonsecretors. Accordingly, the VP8* protein bound nearly all secretor saliva samples, but not those of nonsecretors, explaining the observed infection of secretor individuals only. This is the first single-outbreak-based investigation showing that P[8] rotavirus infected only secretors. Our investigation also suggests that health education of school students is an important countermeasure against an outbreak of communicable disease.

Hard and soft tissue alterations during the healing stage of immediate implant placement and provisionalization with or without connective tissue graft: A randomized clinical trial.

AIMS: To evaluate the hard and soft tissue alterations of immediately placed and provisionalized implants with or without connective tissue graft (CTG). MATERIALS AND METHODS: Single unsalvageable maxillary incisors were replaced with immediately placed and provisionalized implants in 42 participants. The patients were randomly assigned to receive simultaneous CTG (test group) and not receive CTG (control group). Digital impression and cone-beam computed tomography images were obtained before extraction and after 6 months. Mid-facial gingival margin migrations, soft tissue contour changes and hard tissue remodelling were analysed and compared between the two groups using three-dimensional superimposition method. RESULTS: Forty participants completed the study. The test group showed significantly less buccal tissue collapse in the area 2-5 mm apical to the gingival margin. In both groups, the mid-facial gingival margin migrated in an apico-palatal direction and the socket void, except for a triangular space in the bucco-coronal region, demonstrated radiographic new bone formation without statistically significant differences. CONCLUSIONS: The CTG used with immediate implant placement and provisionalization could compensate for the facial tissue collapse, but it did not benefit maintenance of the mid-facial gingival margin position during the 6-month follow-up. New bone formation observed radiographically can be expected in most areas of the socket void, regardless of CTG use (ChiCTR-1900028494).

Repetitive Position Change Improves Gastric Cleanliness for Magnetically Controlled Capsule Gastroscopy.

BACKGROUND AND AIMS: Good gastric preparation is essential for magnetically controlled capsule gastroscopy (MCCG) examination. This study aims to determine if repetitive position change after dimethicone premedication could further improve gastric cleanliness for MCCG. METHODS: Consecutive patients referred for MCCG in our center from May 7 to May 31, 2018 were prospectively enrolled and randomized to undergo repetitive position change for 15 min (position change group) or not (conventional group) after ingesting dimethicone. Primary outcome was gastric cleanliness score and secondary outcomes were detection rate of positive findings, number of lesions per patient, gastric examination time, and safety of MCCG. RESULTS: Totals of 43 and 40 were included in the position change and conventional groups, respectively. Gastric cleanliness score in the position change group was significantly higher than in the conventional group (21.2 ± 1.0 vs. 18.6 ± 2.0, P  < 0.001), as was the proportion of acceptable gastric cleanliness (gastric cleanliness score ≥ 18) (100% vs. 72.5%, P  < 0.001). There was no statistical difference in detection rate of positive findings between the two groups (27.9% vs. 27.5%, P  = 0.97). In the position change group, the gastric examination time was significantly reduced (13.2 ± 4.0 vs. 15.3 ± 5.1, P = 0.043). No adverse events were observed. CONCLUSIONS: Repetitive position change after dimethicone premedication significantly improves gastric cleanliness for MCCG examination. Clinical Trial Registration ClinicalTrials.gov, ID: NCT03514966.

Self-assembly of crystalline nanotubes from monodisperse amphiphilic diblock copolypeptoid tiles.

The folding and assembly of sequence-defined polymers into precisely ordered nanostructures promises a class of well-defined biomimetic architectures with specific function. Amphiphilic diblock copolymers are known to self-assemble in water to form a variety of nanostructured morphologies including spheres, disks, cylinders, and vesicles. In all of these cases, the predominant driving force for assembly is the formation of a hydrophobic core that excludes water, whereas the hydrophilic blocks are solvated and extend into the aqueous phase. However, such polymer systems typically have broad molar mass distributions and lack the purity and sequence-defined structure often associated with biologically derived polymers. Here, we demonstrate that purified, monodisperse amphiphilic diblock copolypeptoids, with chemically distinct domains that are congruent in size and shape, can behave like molecular tile units that spontaneously assemble into hollow, crystalline nanotubes in water. The nanotubes consist of stacked, porous crystalline rings, and are held together primarily by side-chain van der Waals interactions. The peptoid nanotubes form without a central hydrophobic core, chirality, a hydrogen bond network, and electrostatic or π-π interactions. These results demonstrate the remarkable structure-directing influence of n-alkane and ethyleneoxy side chains in polymer self-assembly. More broadly, this work suggests that flexible, low-molecular-weight sequence-defined polymers can serve as molecular tile units that can assemble into precision supramolecular architectures.

High-Throughput Sequencing of Putative Novel microRNAs in Rhesus Monkey Peripheral Blood Mononuclear Cells following EV71 and CA16 Infection.

OBJECTIVES: Enterovirus 71 (EV71) and Coxsackievirus A16 (CA16) remain the major pathogens in hand, foot, and mouth disease (HFMD) cases, but the mechanisms of the different pathogeneses that follow EV71 and CA16 infection remain largely unknown. METHODS: Herein, we utilized microRNA (miRNA) deep sequencing to investigate the roles of novel differentially expressed miRNAs in peripheral blood mononuclear cells (PBMCs) infected with EV71 and CA16. RESULTS: The results identified 13 novel differentially expressed miRNAs in each group. Additionally, the target genes were predicted by the miRanda and RNAhybrid programs, and a total of 2,501 targets were found in the two databases. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that these targets were mainly involved in cell development and were associated with nervous system development, system development, multicellular organism development, the Wnt signaling pathway, the PDGF signaling pathway, and the EGF receptor signaling pathway. Finally, a coexpression regulatory network was built with the key targets to further extrapolate the functional interactions of the targets and their coexpressed genes. CONCLUSION: Our results not only revealed potential biomarkers or targets for the diagnosis and treatment of HFMD, but also provided new insights to explore the mechanisms of EV71 and CA16 pathogenesis.

[A novel technique to preserve the alveolar ridge width following tooth extraction in the maxillary frontal area].

OBJECTIVE: To introduce a novel ridge preservation technique with micro-titanium plate avoiding the use of bone grafting materials, and evaluate the potential horizontal bone preservation effect of this new technique, applied on single maxillary central incisors after tooth extraction for future implant restoration. METHODS: Nine patients (six women and three men), mean age (26.0 ± 5.7) years(from 18 to 34 years) referred to the Department of Oral Implantology, Peking University School and Hospital of Stomotology, were selected and diagnosed with unsalvageable single middle incisor with fine general conditions, no signs of acute local inflammation, no ongoing or previous periodontitis, healthy neighboring teeth and intact buccal bone walls. Tooth extraction, delayed implant placement and implant-supported single crown restoration were selected as treatment plan. The teeth were extracted atraumatically with local anesthesia, followed by a reflection of a minor flap to exposed 2-3 mm of the buccal bone plate. After that, a micro-titanium plate was trimmed and bended to fit the convexity of the labial bone and fixed by two mini pins with intent to support the labial soft tissue. The flap was then repositioned over the micro titanium plate and secured with two single sutures. No bone grafting materials or releasing incisions were needed. The sockets were left to heal without any intention of primary wound closure. Cone-beam computed tomographic (CBCT) scans were obtained before and four months after tooth extraction. Horizontal ridge widths were measured with CBCT software, and the preservation effects were calculated and recorded by the percentage of horizontal ridge alteration. RESULTS: The nine extraction sockets were healed uneventfully. The average socket width before extraction was (7.51 ± 0.48) mm (6.92-7.82 mm). The average alveolar ridge labial-palatal width at the control point of the edentulous area was (6.81±0.44) mm (6.04-7.38 mm) 4 months after tooth extraction, the mean percentage of ridge width preserved was 90.87% ± 2.91% (87.28%-95.60%). CONCLUSION: This novel ridge preservation method by the usage of a micro-titanium plate did not interfere with the natural socket healing process, and at the same time, largely preserved the width of alveolar ridge without any bone grafting procedures. Long term results remain to be seen.

Morphological investigation of midblock-sulfonated block ionomers prepared from solvents differing in polarity.

Recent developments regarding charged multiblock copolymers that can form physical networks and exhibit robust mechanical properties herald new and exciting opportunities for contemporary technologies requiring amphiphilic attributes. Due to the presence of strong interactions, however, control over the phase behavior of such materials remains challenging, especially since their morphologies can be solvent-templated. In this study, transmission electron microscopy and microtomography are employed to examine the morphological characteristics of midblock-sulfonated pentablock ionomers prepared from solvents differing in polarity. Resultant images confirm that discrete, spherical ion-rich microdomains form in films cast from a relatively nonpolar solvent, whereas an apparently mixed morphology with a continuous ion-rich pathway is generated when the casting solvent is more highly polar. Detailed 3D analysis of the morphological characteristics confirms the coexistence of hexagonally-packed nonpolar cylinders and lamellae, which facilitates the diffusion of ions and/or other polar species through the nanostructured medium.

Association between norovirus and rotavirus infection and histo-blood group antigen types in Vietnamese children.

Norovirus and rotavirus are the two most important causes of acute gastroenteritis in children worldwide. Both norovirus and rotavirus recognize human histo-blood group antigens (HBGAs), and multiple binding patterns for HBGAs have been reported. To explore the role of HBGAs in host susceptibility to norovirus and rotavirus, we conducted a cross-sectional study in children hospitalized with diarrhea in northern Vietnam from September 2010 through September 2012. Of 260 children with paired stool and saliva samples, 158 (61%) were classified as HBGA secretors (Lea-b+), 31 (12%) were nonsecretors (Lea+b-), and 71 (27%) were partial secretors (Lea+b+). Norovirus was detected in 50 patients (19%), with viral genotypes GII.3 (n=28) and GII.4 (n=22) being the most common. All children infected with norovirus strains of genotype GII.4 were either HBGA secretors or partial secretors. Of the 28 GII.3 cases, 12 involved HBGA secretors, 11 partial secretors, and 5 nonsecretors. A total of 85 children tested positive for rotavirus, 74 of whom were infected with genotype P[8], 5 with P[4], and 6 with P[6]; all were HBGA secretors or partial secretors. This is the first epidemiological study demonstrating in a population that HBGA phenotype is a key susceptibility factor for both norovirus and rotavirus infections in children.

[Computer-assisted implant restoration of free-end partially edentulous mandible with severe vertical bone deficiency].

OBJECTIVE: To evaluate the applicability, accuracy and clinical outcome of the computer assisted design and computer assisted manufacture (CAD & CAM) tooth-supported implant surgical guide in the mandibular free-end partially edentulous patients with insufficient vertical bone height. METHODS: According to the inclusion criteria, 3 patients (2 women, and 1 man) with the mean age of 45 years (from 44 to 46 years) with 10 implant sites were involved in this study. With the help of Computer-assisted-design software to plan and simulate the surgical strategies, the implant surgical guides were fabricated via the rapid prototyping technique, then the guided implant placement was implemented, finally the post-surgical evaluations were accomplished by the clinical and radiographic examinations. RESULTS: Ten implants were placed in 3 mandibles via the surgical guides, and the implant supported non-split restorations were in place. All the implant restorations revealed good clinical function until the last review. No inferior alveolar nerve injury was detected by the clinical neurosensory test. The immediate post surgical CBCT was performed to confirm a safe distance of 1.5 to 3.0 mm between the implant apical and the nerve canal. The deviations between the planed and the actually placed implant were: coronal deviation (0.84±0.30) mm (0.31-1.24 mm); apical deviation (1.42±0.52) mm (0.52-2.36 mm); angular deviation 7.65°±1.84° (4.43°-9.81°). CONCLUSION: In case of distal free-end partially edentulous with insufficient vertical bone height in the posterior mandibular region, computer assisted surgical design and guided surgery can offer a treatment option with minimal invasiveness and a shorter treatment period, and avoid the complicated bone augmentation procedure and the high risk of nerve transposition. This technique is clinically and technically feasible, but the cases using this technique should be strictly selected according to the indication.

Comparison of robotic system and dynamic navigation for zygomatic implant placement: An in vitro study.

OBJECTIVES: To compare the accuracy of robotic and dynamic navigation systems in assisting zygomatic implant (ZI) using an in vitro model experiment. METHODS: Preoperative cone-beam computed tomography (CBCT) images of patients who underwent ZI treatment between 2011 and 2023 were collected from local databases. Corresponding three-dimensional resin models were printed and assigned to two groups: the robotic and dynamic navigation system groups. Following preoperative plans, ZIs were placed in the models with the assistance of either a robotic or dynamic navigation system. Deviations in the in vitro navigation surgery were measured and compared between the groups. RESULTS: A total of 110 ZIs were placed in 56 models, with 55 ZIs in each group. No significant differences were observed in entry and angle deviations between the groups (p>0.05). However, the exit deviation in the robotic system group (2.39±1.24 mm) was larger than that in the dynamic navigation group (1.83±1.25 mm) (p<0.05). On the exit side, the Z-axis deviation in the robotic group (left: -0.28±1.43 mm, right: -0.21±1.30 mm) was smaller than that in the dynamic navigation group (left: 0.76±1.11 mm, right: 0.85±1.52 mm) (p<0.05), while no significant differences were found in X- and Y-axis deviations (p>0.05). CONCLUSIONS: Compared with the dynamic navigation system, the robotic system can effectively prevent ZI overextension. However, its accuracy on the exit side is slightly lower than that of the dynamic navigation system. CLINICAL SIGNIFICANCE: This preliminary in vitro study showed that the accuracy of the robotic system was slightly inferior to that of the dynamic navigation system in terms of exit deviation when used in ZI placement. Further clinical studies are required to confirm these findings.

The facial-coronal ridge crest alterations after single immediate implant placement and provisionalization with thin buccal plate phenotype in anterior maxilla: A radiographic case-series study.

AIM: To explore the features of and potential landmarks that predict crestal ridge remodeling after immediate implant placement and provisionalization (IIPP) with thin buccal plate phenotype in the anterior maxilla. MATERIALS AND METHODS: Patients requiring IIPP of single maxillary incisor with thin buccal bone plate (<1 mm) were recruited. Cone-beam computed tomography (CBCT), performed before and 6 months after the intervention, were three-dimensionally superimposed. A virtual line connecting the bony emergence points of adjacent teeth was drawn as a reference. The facial-coronal alveolar crest of the extraction socket and healed ridge were located in mesial, middle and distal cross-sectional planes, and linear ridge reductions were measured. The correlation between ridge reduction and local factors was analyzed. RESULTS: Fifty patients were included. From the extraction socket to healed ridge, the alveolar crest underwent linear bone reduction of 1.50 ± 0.50, 1.54 ± 0.66 and 1.65 ± 0.73 mm in the mesial, middle, and distal regions in an apical-palatal direction. The middle region had significantly higher horizontal (facial-palatal) but lower vertical (coronal-apical) bone reduction than the mesial and distal areas (P < 0.01). The facial-coronal ridge crest of the healed ridge located close to the reference line. Ridge reduction positively correlated with the distance between the initial facial-coronal crest of the extraction socket and the reference line (P < 0.01). CONCLUSIONS: Alveolar crest of the socket lost its curvature and tended to attain a flat profile after IIPP due to inconsistent ridge reduction in middle, mesial and distal areas. The reference line may be a potential landmark for predicting the ridge crest after remodeling.

Peri-zygomatic complications on zygomatic implants with or without penetrating the external surface of zygoma: A 2-year retrospective study.

OBJECTIVES: The main purpose of this retrospective study was to assess the difference in the incidence of peri-zygomatic complications (PZCs) when zygomatic implants (ZIs) penetrate or do not penetrate the external surface of zygoma. MATERIALS AND METHODS: This study included 32 patients with edentulous maxillae or potentially edentulous maxillae undergo zygomatic implantation. The patients were divided into the penetration group (P-group) and the non-penetration group (N-group) according to whether the apex of implants penetrated the external surface of zygoma in postoperative CBCT. The extension length, the penetration section of the implants, and the skin thickness at the corresponding position were simultaneously measured. Clinical follow-up was conducted regularly until 2 years after surgery. The occurrence of PZCs (including peri-zygomatic infection, skin numbness, non-infectious pain, and foreign body sensation) was recorded. A mixed effect logistic model was used to compare the difference of complication rate between the P-group and the N-group, and odds ratio (OR) was calculated. Then identify the impact of the extension length, penetration section and skin thickness in P-group with the same model. RESULTS: A total of 71 ZIs were implanted in 32 patients, including 37 implants in the P-group and 34 implants in the N-group. During the 2-year follow-up, a total of 13 implants occurred PZCs, with an overall complication rate of 18.3%. Thereinto, the incidence rate was 29.7% in the P-group, and 5.9% in the N-group (OR = 6.77). In P-group, there was a significant difference in complication rate of different extension lengths, while the penetration section and skin thickness had no statistical significance on the complication rate. CONCLUSION: Under the limitation of this study, to minimize the risk of PZCs, ZI should be placed in a manner that avoids the apex penetrating the external surface of the zygoma.