Clinical accuracy of partially guided implant placement in edentulous patients: A computed tomography-based retrospective study.

OBJECTIVES: This retrospective study was intended to evaluate the clinical accuracy of partially guided template in guiding implant placement in edentulous patients. METHODS: A total of 120 implants were placed in 24 patients with at least one completely edentulous arch with a partially guided system. Based on CBCT data, a repeatable method was used to measure linear and angular deviations of implants at 3D level in Mimics medical software. The influence of supporting tissue and implant region on the accuracy was assessed, followed by the evaluation of direction of linear deviations in biologically vital areas. RESULTS: Linear deviations of all implants were 1.91 ± 0.68 mm, 1.47 ± 0.68 mm, and 1.02 ± 0.69 mm at apical, apical lateral, and apical vertical levels. When at the cervical, cervical lateral, and cervical vertical levels, the linear deviations were 1.53 ± 0.65 mm, 0.98 ± 0.53 mm, and 1.01 ± 0.69 mm, respectively. Angular deviation of all implants was 7.14 ± 3.41°. Implants guided by mucosa + tooth-supported templates showed higher linear deviations at apical vertical level (1.21 ± 0.72 mm vs. 0.86 ± 0.63 mm, p < .05) and cervical vertical level (1.18 ± 0.72 mm vs. 0.87 ± 0.63 mm, p < .05) than mucosa-supported templates, and implants in maxilla were found higher angular deviation than mandible (7.89 ± 3.61° vs. 6.29 ± 2.97°, p < .05). CONCLUSIONS: The partially guided template served as clinically viable surgical assistance in implant placement in edentulous patients. When using mucosa + tooth-supported template or placing implants in maxilla, more caution was required, especially in biologically vital areas.

An Innovative Method for Nasal Alar Reduction Surgery Based on the Equilateral Triangle Design Theory.

At present, there is no unified and accurate method to design the amount of tissue to be removed in alar reduction surgery. The authors present the experience that the crescent-shaped alar resection is based on the innovative equilateral triangle theory. It can accurately estimates the amount of alar tissue to be removed and conforms to the 3-dimensional esthetic concept of the nose. Followed up for 6 to 12 months, took 6 and 12 months postoperative photos, measured the postoperative nasal base width, and conduct a questionnaire satisfaction survey. The width of the nasal base was reduced by an average of 4.4±2.1 mm. The mean visual analog scale score showed: 4.8±1.6 before operation and 7.6±1.2 after the operation ( P <0.05), which revealed satisfactory patient outcomes. This method provides a new idea for the evaluation of nasal alar resection volume and is worthy of clinical application.

Comprehensive Strategies of Flap Design for Repairing Cranium Exposure or Defects After Malignant Tumor Resection.

Free tissue transfer is a great method for the reconstruction of craniofacial defects, especially in complicated situations such as calvarial defects and dura exposure. Latissimus dorsi muscle flap, anterolateral thigh flap, and radial forearm flap are 3 commonly used flaps that have distinct characteristics. The objective of the present study is to share our experiences with microvascular free flap reconstruction of cranium exposure or defects and to compare distinct microvascular free flap options. The authors reviewed 8 cases that received resection and reconstruction of craniofacial tumors. Perioperative and reconstructive techniques employed to improve flap survival, esthetic outcome, and prevent complications in these patients were retrospectively detailed. In addition, the advantages and disadvantages of latissimus dorsi muscle flap, anterolateral thigh flap, and radial forearm flap were illustrated in this study. The authors believe that taking advantage of these flaps according to the characteristics of defects and flaps will contribute to a good functional and esthetic outcome.

Relevant factors of posterior mandible lingual plate perforation during immediate implant placement: a virtual implant placement study using CBCT.

BACKGROUND: To explore the influence of cross-sectional type and morphological parameters at the mandibular molar sites on lingual plate perforation (LPP) during the immediate implant placement (IIP). METHODS: 181 implants were virtually placed in the mandibular molar sites on the cone beam computed tomography (CBCT). Each cross-section of the implantation site was divided into the Undercut (U)/Parallel (P)/Convex (C) types. Morphologically relevant parameters were measured on the cross-sections, including width of the upper end (Wb), width of the lower end (Wc), vertical height (V), angle between the natural crown axis and the alveolar bone axis (∠ß), LC depth (LCD), LC height, and angle between the horizontal line and the line connecting the most prominent point and the most concave point of lingual plate (∠α). Besides, the distance from the end of the virtual implant and the lingual bone plate of the cross-section (DIL) was calculated. Relationships between all the morphologically relevant parameters and the DIL were further analyzed. RESULTS: A total of 77 (42.5%) cross-sections were classified as U-type, which was the most common one, accounting for 63% of the second molar regions. All LPP cases and most of the nearly LPP (87.9%) cases occurred at the U-type cross-sections, and the relationship between the DIL and the morphological parameters can be expressed by a multivariate linear equation. CONCLUSIONS: The occurrence rate of U-type cross-sections in the second molar region was very high, and the risk of LPP should be considered during IIP. Except for the U-type, significant large LCD, small Wc, and large âˆ ß were the important relevant factors. CBCT and multivariate linear equations could help to assess the LPP risk and provide a reference for implant placement design pre-surgery.

Identification of key module and hub genes in pulpitis using weighted gene co-expression network analysis.

BACKGROUND: Pulpitis is a common disease mainly caused by bacteria. Conventional approaches of diagnosing the state of dental pulp are mainly based on clinical symptoms, thereby harbor deficiencies. The accurate and rapid diagnosis of pulpitis is important for choosing the suitable therapy. The study aimed to identify pulpits related key genes by integrating micro-array data analysis and systems biology network-based methods such as weighted gene co-expression network analysis (WGCNA). METHODS: The micro-array data of 13 inflamed pulp and 11 normal pulp were acquired from Gene Expression Omnibus (GEO). WGCNA was utilized to establish a genetic network and categorize genes into diverse modules. Hub genes in the most associated module to pulpitis were screened out using high module group members (MM) methods. Pulpitis model in rat was constructed and iRoot BP plus was applied to cap pulp. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used for validation of hub genes. RESULTS: WGCNA was established and genes were categorized into 22 modules. The darkgrey module had the highest correlation with pulpitis among them. A total of 5 hub genes (HMOX1, LOX, ACTG1, STAT3, GNB5) were identified. RT-qPCR proved the differences in expression levels of HMOX1, LOX, ACTG1, STAT3, GNB5 in inflamed dental pulp. Pulp capping reversed the expression level of HMOX1, LOX, ACTG1. CONCLUSION: The study was the first to produce a holistic view of pulpitis, screen out and validate hub genes involved in pulpitis using WGCNA method. Pulp capping using iRoot BP plus could reverse partial hub genes.

Accuracy evaluation of cone beam computed tomography applied to measure peri-implant bone thickness in living patients: an ex vivo and in vivo experiment.

OBJECTIVES: This study aims to study the accuracy of cone beam computed tomography (CBCT) for measuring peri-implant bone thickness in living patients via a novel visualization method (NVM). MATERIAL AND METHODS: The validity of the NVM was verified ex vivo by measuring the same peri-implant bone thicknesses in bovine ribs by using raw postoperative CBCT (clinical measurement, CM), the visualized fused images obtained using the NVM (visualized fused measurement, VF), and hard tissue sections (gold standard measurement, GS). The NVM was applied by deconstructing the postoperative CBCT model into the Modelpost-bone and Modelimplant and replacing it with bone from preoperative CBCT and standard implant models, respectively. In vivo, 52 implants were included, and the VF of each implant was obtained using data processing methods similar to those used ex vivo. Then, we compared the results of CM and VF. RESULTS: Ex vivo, the VF was similar to GS, while CM usually underestimated the peri-implant bone thickness, especially at the implant shoulder (P < 0.01). In vivo, on CBCT, areas with a peri-implant bone thickness of 0-0.50 mm were not visible, while those with a thickness of 0.50-1.00 mm were occasionally visible. There was less underestimation of bone along the implant long axis. CONCLUSIONS: Thin peri-implant bones could be completely underestimated on CBCT. CBCT scans alone are insufficient to warrant surgical intervention. Our NVM facilitates the accurate visual assessment of implant dimensions. CLINICAL RELEVANCE: The thickness of peri-implant bone could be completely underestimated when thinner than 1.0 mm in living patients. Familiarity with these confusing CBCT results may help clinicians and patients avoid further unnecessary evaluation, misdiagnosis, and invasive treatment.

The comparative evaluation of transcrestal and lateral sinus floor elevation in sites with residual bone height ≤6 mm: A two-year prospective randomized study.

OBJECTIVES: To compare clinical and radiographic outcomes between transcrestal sinus floor elevation (TSFE) and lateral sinus floor elevation (LSFE) approaches of simultaneous implant placement in atrophic maxilla. MATERIALS AND METHODS: Patients with a residual bone height (RBH) ≤6 mm were enrolled and randomly assigned to TSFE and LSFE groups. Patients in both groups simultaneously underwent sinus floor elevation with bovine-derived xenograft and implant placement. Clinical and radiographic results were evaluated immediately after surgery and after 6, 12, 18, and 24 months. The endo-sinus bone gain (ESBG), apical implant bone height (ABH), endo-sinus bone-implant contact rate (EBICR), and crestal bone level (CBL) were assessed using panoramic radiographs. RESULTS: Forty-one implants (TSFE: 21, LSFE: 20) were placed in cases with a mean RBH of 3.77 ± 1.16 mm. All implants obtained clinical success and satisfactory ESBG at 24 months. No significant differences were found in ESBG and ABH between two groups immediately after surgery, but LSFE group showed significantly higher values than TSFE group thereafter. Grafts in TSFE group reached stability 6 months earlier than that in LSFE group. In both groups, EBICR was almost 100%, and CBL showed no detectable changes. CONCLUSIONS: LSFE can achieve higher ESBG 2 years after surgery. Otherwise, TSFE could be an alternative to LSFE, when the access for lateral window preparation is limited. Both approaches were highly predictable for RBH ≤6 mm during 24-month observation period for the implants placed simultaneously.

Close-Packed Langmuir Monolayers of Saccharide-Based Carbon Dots at the Air-Subphase Interface.

Carbon dots (CDs) are zero-dimensional carbon-based spherical nanoparticles with diameters less than 10 nm. Here, we report for the first time CDs forming stable Langmuir monolayers at the air-subphase interface. Langmuir monolayers are of great interest both fundamentally to study the interactions at the interfaces and for many applications such as the development of sensors. However, CDs usually do not form Langmuir monolayers because of their highly hydrophilic nature. In this study, amphiphilic CDs were prepared through hydrothermal carbonization using saccharides as the precursors. The surface chemistry behavior and optical properties of CDs at the air-subphase interface were studied. CDs derived from saccharides consistently formed stable Langmuir monolayers which show all essential phases, namely, gas, liquid-expanded, liquid-condensed, and solid phases. The compression-decompression cycle method showed minimum hysteresis (4.3%), confirming the retaining capacity of the CDs as a monolayer. Limiting CD areas from surface pressure-area isotherm at the air-subphase interface were used to calculate the average diameter of the CDs at the air-subphase interface. UV/vis absorption spectra of CDs dispersed in water and in Langmuir monolayers had the same bands in the UV region. The intensity of the UV/vis absorption increases with increasing surface pressure at the air-subphase interface. Interestingly, photoluminescence (PL) of the Langmuir monolayer of CDs was excitation-independent, whereas the same CDs had excitation-dependent PL when dispersed in water.

Quantification of Nucleic Acid Concentration in the Nanoparticle or Polymer Conjugates Using Circular Dichroism Spectroscopy.

The interface of nucleic acids and nanomaterials is among the most promising fields in recent years. Considerable efforts have been devoted to the development of novel systems based on the two components for various promising applications such as sensing, bioimaging, drug delivery, and theranostics. However, the determination of nucleic acid concentration in these systems remains as a challenge due to the interference of nanoparticles. To this end, we developed a simple, yet reliable, method to quantify the nucleic acid concentration in their nanoparticle or polymer conjugates based on circular dichroism (CD) spectroscopy. In this paper, three nucleic acids, namely, DNA sodium salt from calf thymus (NaDNA), DNA from herring sperm (hsDNA), and ribonucleic acid from torula yeast (tyRNA), were noncovalently conjugated to three nanoparticles. The concentrations of the three nucleic acids in their nanoparticle conjugates were successfully determined on the basis of CD spectra calibration curves.

Trend of Cadherin-11 expression and its impact on cartilage degradation in the temporomandibular joints of guinea pigs with spontaneous osteoarthritis.

BACKGROUND: This study aims to investigate spatial and temporal changes in cadherin-11 (CAD-11) expression and their effects on cartilage degeneration in the temporomandibular joint (TMJ) of guinea pigs with spontaneous osteoarthritis (OA). METHODS: Dunkin-Hartley (DH) and Bristol strain 2 (BS2) guinea pigs at ages of 1, 3, 6, 9, and 12 months were categorized into two groups and analyzed. The bilateral TMJ condyles of DH and BS2 guinea pigs were harvested and fixed. The distribution and expression profiles of CAD-11, collagen type II, and matrix metalloproteinase 3 (MMP-3) were detected by immunohistological assays. Histological micrographs of the condyle cartilage were obtained and analyzed. RESULTS: Osteoarthritis can be spontaneously induced by mechanical stress in DH guinea pigs. The main histopathological changes in the TMJ structure and increased expression of MMP-3 occurred within 6-9 months of ages in DH guinea pigs with spontaneous OA. By contrast, minimal to mild cartilage degradations were observed in the TMJ of BS2 guinea pigs even at the age of 12 months. From as early as 3 months of age, the expression levels of CAD-11 were upregulated in the TMJ of DH guinea pigs compared with those in BS2 animals. CAD-11 expression differed between the two groups at 12 months of age. CONCLUSIONS: Increased CAD-11 expression within cartilage is associated with the development and progression of OA between the two strains of guinea pigs. Therefore, CAD-11 expression in TMJ could be an important predisposing factor for the development of spontaneous OA.

A modified technique for expanded polytetrafluoroethylene shaping in chin augmentation: parallel groove carving technique.

OBJECTIVE: In the current study, we restricted our focus on a modified approach to address the poor curved attachment of expanded polytetrafluoroethylenein chin augmentation. METHOD: The implant is shaped generally in accordance with the chin, followed by 5-to-8 longitudinally parallel "V"-grooves carved in the median of posterior site where the implant directly attaches to the mandible. Thus, it enhances bend ductility of the prosthesis and renders better attachment from the curved surface of prosthesis to the mandibular embedded region. RESULTS: This procedure was performed in 15 patients. After follow-up for 2 to 6 months, there were no complications observed postoperatively including mobilization, dead space, subcutaneous dropsy, topical infection, or palpable edges in the subcutaneous area. CONCLUSIONS: The introduction of longitudinally parallel V-groove technique provides an effective method for avoidance of increasing hardness, decreasing flexibility, and palpable edges after implantation.As a novel and effective technique, it is beneficial for better attachment and satisfactory outcome without causing extra expenses.

The relationship between partial disc displacement and mandibular dysplasia in female adolescents.

BACKGROUND: The objective of the present study was to investigate the possible relationship between partial disc displacement of the temporomandibular joint (TMJ) and mandibular dysplasia. MATERIAL/METHODS: The TMJ disc position of 46 female adolescents, with Class II, Division 1 malocclusion, aged 10.1 approximately 12.8 years, was quantitatively measured with magnetic resonance imaging (MRI) examinations. Meanwhile, mandibular size and form were determined from cephalometric radiographs. The possible correlation between disc status and mandibular morphology was assessed by means of the Pearson Correlation. In addition, the differences in mandibular size and form between the partial disc displacement group (displaced group) and the disc normal group were also assessed. RESULTS: The results of Pearson Correlation showed that the displaced group had shorter mandibular body length and total mandibular length (Go-Po/Ca-Dm, r=-0.500; Go-Po/ Dp-Cc/Cs-Cc, r=-0.500; Ar-Me/ Ca-Dm, r=-0.459). The patients with horizontal growing style presented more anterior displaced disc (N-S-Gn/ Ca-Dm, r=-0.492). Furthermore, a significantly shorter mandibular body length (Go-Po), a steeper mandibular plane (MP/FH) and a more obtuse mandibular angle (Ar-Go-Me) were found in the displaced group. However, no relationship between the size of the vertical mandible and the disc status was noticed. CONCLUSIONS: Partial disc displacement in Class II, Division 1 cases may be associated with the mandible with horizontal deficits instead of the mandible with vertical deficits.

Likelihood of needing facial bone augmentation in the anterior maxilla of Chinese Asians: A cone beam computed tomography virtual implant study.

BACKGROUND: The perfect position and axis of an implant is often limited by the morphology of the alveolar ridge, especially in Asians. PURPOSE: The aim of this study was to investigate the frequency at which ideal implant placement position in the anterior maxilla of Chinese Asians would require facial bone augmentation given by an initial facial bone profile. MATERIALS AND METHODS: Implants were virtually placed in 303 sites without tooth loss in the anterior maxilla. The incidence and characters of implant facial plate fenestration were analyzed. If there was no facial fenestration, the thinnest buccal plate (TB) amount adjacent to the implant was measured and recorded. RESULTS: A total of 79 (26.07%) sites showed fenestrations. The mean length, width, and area of exposure in the fenestration sites were 2.94 ± 1.67 mm, 1.52 ± 0.97 mm, and 2.84 ± 3.13 mm2 , respectively. In the nonfenestrated sites, the TB of facial bone around the virtual implants was 1.10 ± 0.78 mm. Among the 224 nonfenestrated sites, 126 sites had a TB of less than 1 mm. CONCLUSIONS: It can be concluded that the initial facial bone profile should be considered when designing restorations and choosing an optimal implant position in the anterior maxilla.

Carbon dots: promising biomaterials for bone-specific imaging and drug delivery.

Bone-related diseases and dysfunctions are heavy burdens on our increasingly aged society. One important strategy to relieve this problem is through early detection and treatment of bone-related diseases. Towards this goal, there has been constant interest in developing novel bone-specific materials for imaging and drug delivery. Currently, however, materials that have high affinity and specificity towards bone are very limited. Carbon dots (C-dots) synthesized from carbon nanopowder bind to calcified bones in vivo with high affinity and specificity. In this study we show that bone binding is highly unique to a specific type of C-dot, and that this binding is non-toxic. Significantly, C-dots derived from other raw materials did not show any bone binding properties. These differences are attributed to the differences in surface chemistry of C-dot preparations, highlighting the heterogeneous nature of C-dots. Importantly, bone-binding by carbon nanopowder derived C-dots is not significantly altered by chemical functionalization of their surface. These unique properties indicate the potential applications of carbon nanopowder-derived C-dots as highly bone-specific bioimaging agents and drug carriers.

An animal model for inducing anterior disc displacement of the temporomandibular joint.

AIMS: To develop an animal model of anterior disc displacement (ADD) without the need for opening the temporomandibular joint (TMI) capsule. METHODS: Thirty-two healthy adult Japanese white rabbits were used in this study. Four rabbits were dissected to familiarize the investigators with the anatomy of the TMJ. Sixteen animals were subjected to surgical ADD in the right TMJ, 8 animals had a sham operation, and 4 animals were not operated (normal controls). Four rabbits from the experimental ADD group and 2 from the sham group were sacrificed 1, 2, 4, and 8 weeks, respectively. The rabbits in normal control group were sacrificed at the beginning of the experiment. Animal behaviors as well as macro- and microchanges in the TMJs were investigated. RESULTS: Fifteen right TMJ discs in the 16 experimental rabbits were successfully displaced anteriorly, and the degree of ADD in the experimental group was similar. The mandible of each ADD rabbit deviated to the left side with inclined attrition of the incisors. Some histologic changes appeared in the experimental TMJs. CONCLUSION: This ADD technique without the need for opening the TMJ capsule is effective, and the model is suitable for studying ADD of the TMJ.

Mandibular lateral shift induces the increased expression of TGF-ß, VEGF, and Col-II in the condyle of rat temporomandibular joints.

OBJECTIVE: The present study evaluates histologic changes to and expression of angiogenic factors in rats with mandibular functional shift (MFS). STUDY DESIGN: After 1, 2, and 4 weeks of MFS, rats in the experimental and control groups were killed. Histologic micrographs of the ipsilateral condyle cartilage were obtained. The localization and expression of vascular endothelial growth factor (VEGF), transforming growth factor beta (TGF-ß), and type-II collagen (Col-II) in temporomandibular joints (TMJs) were evaluated through immunohistochemical staining. RESULTS: The results showed that structural changes in the condyle cartilage could be observed 2 weeks after MFS. TGF-ß expression reached its peak 2 weeks post-MFS, whereas VEGF and Col-II reached their peaks 4 weeks posttreatment. CONCLUSIONS: Compressive forces applied to the TMJ could enhance the expressions of VEGF, TGF-ß, and Col-II, and activate angiogenesis. The proteins appear to play important roles in the remodeling of the TMJ.

[Experimental study on acellular bovine pericardium guided bone regeneration material].

OBJECTIVE: To choose the best procedure on preparation of acellular bovine pericardium (ABP) guided bone regeneration (GBR) material. METHODS: The BP was decellularized with 0. 25% Trypsin + 0.5% Triton X-100. The acellular bovine pericardiums (ABPs) were treated with phosphate-buffered saline(PBS) (group A), 95% glycerol (group B), EDAC (group C), and EDAC and 95% glycerol (group D) respectively. The treated ABPs were implanted subcutaneously in the back of SD rats respectively at random and no material was implanted as control. Seven rats were sacrificed at 2 weeks, twelve at 4 weeks, twelve at 8 weeks, seven at 16 weeks. Local reaction was studied grossly. The amount of antigen presenting cell (APC) and the percentage of ABP degeneration were reckoned by images analysis system. RESULTS: The ABPs were replaced by fibroblasts completely in group A at 8 weeks, in group C at 16 weeks, but only less than 50% till 16 weeks in groups B and D. In all groups, the depth of surrounding fibres attenuated time-dependently. The APC amount of the groups B and D was higher than that of the control group, and the ABP of the groups B and D degraded partly at 16 weeks. CONCLUSION: The ABP treated with EDAC can be replaced by the surrounding tissues and has good biocompatibility.

[Experimental study on guiding bone regeneration with bovine pericardium membrane].

OBJECTIVE: To explore the feasibility of bovine pericardium used as a material for guiding bone regeneration. METHODS: 1 cm x 1 cm x 0.5 cm defects were created on both buccal sides of the mandibles of 11 dogs. One side was covered with Glutaraldehyde (GA) cross-linking bovine pericardium; no membrane covered side was used as control. The animals were sacrificed in 2 weeks, 4 weeks, 8 weeks and 16 weeks after operation to observe the repair of the bone defects. RESULTS: (1) Wounds healed well in 10 dogs. Meanwhile, wounds in dogs of 16 weeks group healed badly and severe inflammatory response was found in bovine pericardium treated area. (2) The pericardium can be maintained in vivo for 16 weeks without absorption, there were only mild inflammatory cells invading. (3) The bone defects covered with bovine pericardium repaired better than control groups significantly. CONCLUSION: (1) GA bovine pericardium have the effect on guiding bone regeneration in the repair of dog experimental bone defects and it is possible that the bovine pericardium will be used as a new kind of GBR material; (2) GA bovine pericardium has good biocompatibility.