Debridement of contaminated implants using air-polishing coupled with pH-responsive maximin H5-embedded metal-organic frameworks.

The primary goal of peri-implantitis treatments remains the decontamination of implant surfaces exposed to polymicrobial biofilms and renders biocompatibility. In this study, we reported a synergistic strategy for the debridement and re-osteogenesis of contaminated titanium by using erythritol air abrasion (AA) coupled with an as-synthesized pH-responsive antimicrobial agent. Here, the anionic antibacterial peptide Maximin H5 C-terminally deaminated isoform (MH5C) was introduced into the Zeolitic Imidazolate Frameworks (ZIF-8) via a one-pot synthesis process. The formed MH5C@ZIF-8 nanoparticles (NPs) not only possessed suitable stability, but also guarantee the slow-release effect of MH5C. Antibacterial experiments revealed that MH5C@ZIF-8 NPs exhibited excellent antimicrobial abilities toward pathogenic bacteria of peri-implantitis, confirming ZIF-8 NPs as efficient nanoplatforms for delivering antibacterial peptide. To evaluate the comprehensive debridement efficiency, single-species as well as mixed-species biofilms were successively established on commercially used titanium surfaces and decontaminated with different methods: removed only by erythritol air abrasion, treated merely with MH5C@ZIF-8 NPs, or received both managements. The results demonstrated that only erythritol air abrasion accompanied with MH5C@ZIF-8 NPs at high concentrations eliminated almost all retained bacteria and impeded biofilm rehabilitation, while neither erythritol air abrasion nor MH5C@ZIF-8 NPs alone could achieve this. Subsequently, we evaluated the re-osteogenesis on previously contaminated surfaces which were treated with different debridement methods afterwards. We found that cell growth and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) in the group received both treatments (AA + MH5C@ZIF-8) were higher than those in other groups. Our work emphasized the great potential of the synergistic therapy as a credible alternative for removing microorganisms and rendering re-osseointegration on contaminated implant surfaces, boding well for the comprehensive applications in peri-implantitis treatments.

Deep learning based dental implant failure prediction from periapical and panoramic films.

Background: Dental implant failure is a critical condition that can seriously compromise therapeutic efficacy. Insufficient bone volume, unfavorable bone quality, periodontal bone loss, and systemic conditions, including osteopenia/osteoporosis and diabetes mellitus, have been associated with implant failure. Early indicators of potential implant failure could help mitigate the risk of severe complications. This study aimed to develop an effective implant outcome prediction model using dental periapical and panoramic films. Methods: A total of 248 patients (89 with failed implants and 159 with successful implants) were examined. A total of 529 periapical images and 551 panoramic images were collected from the patients for a deep learning-based model. Based on radiographic peri-implant alveolar bone pattern, implant outcome was divided into three categories: implant failure with marginal bone loss, implant failure without marginal bone loss, and implant success. We extracted features using a deep convolutional neural network (CNN) and built a hybrid model to combine periapical and panoramic images. A comparison among three categories of receiver operating characteristic (ROC) curves was performed. The diagnostic accuracy, precision, recall and F1-score of the dataset were assessed. Results: Our model achieved an AUC (area under the ROC curve) of 0.972 for failure with marginal bone loss, 0.947 for failure without marginal bone loss and 0.975 for success. In all conditions, for periapical images alone, the diagnostic accuracy was 78.6%; the precision was 0.84, recall was 0.73, and F1-score was 0.75. For panoramic images alone, the diagnostic accuracy was 78.7%; the precision was 0.87, recall was 0.63, and F1-score was 0.66. Both periapical and panoramic images were used in our novel method, and the prediction accuracy was 87%. The precision was 0.85, recall was 0.88, and F1-score was 0.85. Conclusions: The deep learning model used features from periapical and panoramic images to effectively predict the occurrence of implant failure and might facilitate early clinical intervention for potential dental implant failures.

Clinical, radiographic, and immunological evaluation of angulated screw-retained and cemented single-implant crowns in the esthetic region: A 1-year randomized controlled clinical trial.

BACKGROUND: Screw-retained implant crowns are considered more biologically compatible than cemented crowns due to the absence of excess cement. However, traditional screw-retained implant crowns are not viable when the access hole of the screw channel would need to be located in an esthetic area, which would compromise the esthetic outcome of the treatment. PURPOSE: To evaluate the clinical, radiographic, and immunological outcomes of angulated screw-retained and cemented single-implant crowns in the esthetic region. MATERIALS AND METHODS: The study was a single-center, open-label, randomized controlled clinical trial. Eligible patients were randomly placed in two groups: angulated screw-retained group (AG) and cemented group (CG). Implant survival rate, bleeding on probing rate (BOP%), probing depth (PD), modified plaque index (mPI), marginal bone loss (MBL), concentrations of pro-inflammatory cytokines (TNF-α, IL-6) in peri-implant crevicular fluid (PICF), mechanical complications, and pink esthetic score/white esthetic score (PES/WES) were evaluated. RESULTS: Fifty-six patients (AG: 29, CG: 27) attended the 1-year examination. The drop-out rate was 6.67%. No implant failure was found in both groups during the observation period. BOP% was significantly lower in the AG than that in the CG (mean, 21.84% ± 19.97% vs. 37.04% ± 26.28%, p = 0.018). The concentration of TNF-α in PICF was significantly higher in the AG than that in the CG (median, 13.54 vs. 4.62, p = 0.019). No significant difference of PD, mPI, MBL, IL-6, or mechanical complication rates was found between the two groups. Mean scores for PES/WES were 21.71 and 21.64 in the AG and CG, respectively. CONCLUSION: Based on the present results, both treatment options showed acceptable clinical outcomes in the short term. Angulated screw-retained crowns might benefit the peri-implant soft tissue. However, studies with long-term follow-up are needed to confirm whether the higher concentration of TNF-α will compromise the long-term outcomes of treatment.

Melatonin prevents peri­implantitis via suppression of TLR4/NF-κB.

Peri­implantitis, which is characterized by peri­implant mucositis and alveolar bone resorption, significantly shortens the service life of dental implants. Melatonin is well-known for its anti-inflammatory and osteoprotective activities. Nevertheless, the effects and mechanisms of melatonin to prevent peri­implantitis remain unknown. In this study, the lipopolysaccharide-induced peri­implantitis model was established after the titanium implants were osseointegrated, and the rats received daily administrations of melatonin. The gingival fibroblasts and osteoclasts/osteoblasts were also co-cultured to simulate the inflammatory environment in vitro. We found that prophylactic administration of melatonin decreased proinflammatory cytokine levels and osteoclast numbers, attenuated alveolar bone resorption, and reduced the incidence of peri­implantitis in vivo. Furthermore, melatonin suppressed osteoclastic formation and function in the inflammatory co-culture environment, while melatonin promoted osteoblastic differentiation and function in the in vitro model. Mechanistically, melatonin reduced TLR4 protein levels, and inhibited activation of NF-κB to downregulate the levels of TNF, IL-1ß, and IL-6. These data showed that melatonin was a potent agent to prevent peri­implantitis through inhibiting TLR4/NF-κB signaling. Our findings provide a novel strategy to prevent peri­implantitis, and expand the applications of melatonin. STATEMENT OF SIGNIFICANCE: Dental implants have become the first choice for restoring partial and full edentulism, but its service life is seriously affected by peri­implantitis. Exploration of novel and effective approaches to prevent peri­implantitis is an important and urgent need. In the present study, we have reported for the first time that prophylactic administration of melatonin delayed the occurrence and reduced the incidence of peri­implantitis by decreasing proinflammatory cytokine levels, inhibiting osteoclastogenesis, and promoting osteogenesis. The study is expected to have an important significance on the prevention of peri­implantitis.

Intra- and inter-observer agreements in detecting peri-implant bone defects between periapical radiography and cone beam computed tomography: A clinical study.

BACKGROUND/PURPOSE: Information regarding agreements between periapical radiograph (PA) and cone beam computed tomography (CBCT) in detecting peri-implant defect is still scarce. The aim of this clinical study was to compare agreements between PA and CBCT in detecting peri-implant bone defect. MATERIALS AND METHODS: This retrospective clinical study enrolled 32 patients with both PA and CBCT filmed right after implant placement. Four modalities were used for film reading: PA1 (original), PA2 (enhanced brightness/contrast), CBCT1 (selected axial and mesial-distal direction images) and CBCT2 (all data with software). 2 experienced and 2 inexperienced observers scored all films. Intra- and inter-observer agreements were estimated with Cohen's kappa coefficient. Categorized agreements were compared and differences among four modalities were calculated. RESULTS: Agreements of PA were better than CBCT when detecting peri-implant bone defects in inter-observer agreements (median kappa 0.471 vs. 0.192; p = 0.016). Moreover, agreements in experienced observers were better than inexperienced observers (median kappa 0.883 vs. 0.567; p < 0.001). There was significant difference among four modalities except for experienced observer 2 (p = 0.218). CONCLUSION: Agreements of PA are better than CBCT when detecting peri-implant bone defects, especially for inter-observer agreements. Experienced observers are more consistent in assessment than inexperienced ones.

Circ_0008542 in osteoblast exosomes promotes osteoclast-induced bone resorption through m6A methylation.

With an increasing aging society, China is the world's fastest growing markets for oral implants. Compared with traditional oral implants, immediate implants cause marginal bone resorption and increase the failure rate of osseointegration, but the mechanism is still unknown. Therefore, it is important to further study mechanisms of tension stimulus on osteoblasts and osteoclasts at the early stage of osseointegration to promote rapid osseointegration around oral implants. The results showed that exosomes containing circ_0008542 from MC3T3-E1 cells with prolonged tensile stimulation promoted osteoclast differentiation and bone resorption. Circ_0008542 upregulated Tnfrsf11a (RANK) gene expression by acting as a miR-185-5p sponge. Meanwhile, the circ_0008542 1916-1992 bp segment exhibited increased m6A methylation levels. Inhibiting the RNA methyltransferase METTL3 or overexpressing the RNA demethylase ALKBH5 reversed osteoclast differentiation and bone resorption induced by circ_0008542. Injection of circ_0008542 + ALKBH5 into the tail vein of mice reversed the same effects in vivo. Site-directed mutagenesis study demonstrated that 1956 bp on circ_0008542 is the m6A functional site with the abovementioned biological functions. In conclusion, the RNA methylase METTL3 acts on the m6A functional site of 1956 bp in circ_0008542, promoting competitive binding of miRNA-185-5p by circ_0008542, and leading to an increase in the target gene RANK and the initiation of osteoclast bone absorption. In contrast, the RNA demethylase ALKBH5 inhibits the binding of circ_0008542 with miRNA-185-5p to correct the bone resorption process. The potential value of this study provides methods to enhance the resistance of immediate implants through use of exosomes releasing ALKBH5.

Improved response of human gingival fibroblasts to titanium coated with micro-/nano-structured tantalum.

OBJECTIVES: This study aims to evaluate the ability of tantalum-coated titanium to improve human gingival fibroblasts' adhesion, viability, proliferation, migration performance, and the potential molecular mechanisms. MATERIALS AND METHODS: Titanium plates were divided into two groups: (1) no coating (Ti, control), (2) Tantalum-coated titanium (Ta-coated Ti). All samples were characterized by scanning electronic microscopy, surface roughness, and hydrophilicity. Fibroblasts' performance were analyzed by attached cell number at 1 h, 4 h, and 24 h, morphology at 1 h and 4 h, viability at 1 day, 3 days, 5 days, and 7 days, recovery after wounding at 6 h, 12 h, and 24 h. RT-PCR, western blot were applied to detect attachment-related genes' expression and protein synthesis at 4 h and 24 h. Student's t test was used for statistical analysis. RESULTS: Tantalum-coated titanium demonstrates a layer of homogeneously distributed nano-grains with mean diameter of 25.98 (± 14.75) nm. It was found that after tantalum deposition, human gingival fibroblasts (HGFs) adhesion, viability, proliferation, and migration were promoted in comparison to the control group. An upregulated level of Integrin ß1 and FAK signaling was also detected, which might be the underlying mechanism. CONCLUSION: In the present study, adhesion, viability, proliferation, migration of human gingival fibroblasts are promoted on tantalum-coated titanium, upregulated integrin ß1 and FAK might contribute to its superior performance, indicating tantalum coating can be applied in transmucosal part of dental implant. CLINICAL SIGNIFICANCE: Tantalum deposition on titanium surfaces can promote human gingival fibroblast adhesion, accordingly forming a well-organized soft tissue sealing and may contribute to a successful osseointegration.

Bovine-Derived Xenografts Immobilized With Cryopreserved Stem Cells From Human Adipose and Dental Pulp Tissues Promote Bone Regeneration: A Radiographic and Histological Study.

Adipose tissue-derived stem cells (ADSCs) and dental pulp stem cells (DPSCs) have become promising sources for bone tissue engineering. Our study aimed at evaluating bone regeneration potential of cryopreserved ADSCs and DPSCs combined with bovine-derived xenografts with 10% porcine collagen. In vitro studies revealed that although DPSCs had higher proliferative abilities, ADSCs exhibited greater mineral depositions and higher osteogenic-related gene expression, indicating better osteogenic differentiation potential of ADSCs. After applying cryopreserved ADSCs and DPSCs in a critical-sized calvarial defect model, both cryopreserved mesenchymal stem cells significantly improved bone volume density and new bone area at 2, 4, and 8 weeks. Furthermore, the combined treatment with ADSCs and xenografts was more efficient in enhancing bone repair processes compared to combined treatment with DPCSs at all-time points. We also evaluated the sequential early bone healing process both histologically and radiographically, confirming a high agreement between these two methods. Based on these results, we propose grafting of the tissue-engineered construct seeded with cryopreserved ADSCs as a useful strategy in accelerating bone healing processes.

Peri-implant tissue alteration around tissue-level and bone-level implants in fresh extraction sockets: a histomorphometric study in dogs.

BACKGROUND: To compare tissue alteration in fresh extraction sockets between bone-level and tissue-level implants with different neck designs. METHODS: Bilateral premolars of 6 adult Labrador dogs were extracted, and 24 bone-level and tissue-level implants with two different neck designs were immediately placed. At the same time, buccal bony wall thickness in fresh extraction sockets was also recorded. The Straumann® Bone Level (BL) and Standard Plus (SP) implants were positioned at two insertion depths: 1mm below and flush with the alveolar crest. All animals were sacrificed 6 months after the implant placement. Undecalcified block sections were obtained for histological measurement. Vertical bone resorption and biological widths were documented. Statistical analysis consisted of two sample t-test and Wilcoxon sign-rank test. RESULTS: All implants were histologically osseointegrated. There was no significant difference between BL implants and SP implants in vertical bone resorption regardless of the insertion depths (P>0.05). Meanwhile, significant difference was found in lingual biological width between BL (3.16 mm) and SP (2.43 mm) implants when placed 1mm below the alveolar crest (P<0.05). CONCLUSIONS: Within the limits, it seemed that different implant neck designs had little effect on bone remodeling in fresh extraction sockets. However, longer biological width was found in bone-level implants.

The combination of multi-functional ingredients-loaded hydrogels and three-dimensional printed porous titanium alloys for infective bone defect treatment.

Biomaterial with the dual-functions of bone regeneration and antibacterial is a novel therapy for infective bone defects. Three-dimensional (3D)-printed porous titanium (pTi) benefits bone ingrowth, but its microporous structure conducive to bacteria reproduction. Herein, a multifunctional hydrogel was prepared from dynamic supramolecular assembly of sodium tetraborate (Na2B4O7), polyvinyl alcohol (PVA), silver nanoparticles (AgNPs) and tetraethyl orthosilicate (TEOS), and composited with pTi as an implant system. The pTi scaffolds have ideal pore size and porosity matching with bone, while the supramolecular hydrogel endows pTi scaffolds with antibacterial and biological activity. In vitro assessments indicated the 3D composite implant was biocompatible, promoted bone marrow mesenchymal stem cells (BMSCs) proliferation and osteogenic differentiation, and inhibited bacteria, simultaneously. In vivo experiments further demonstrated that the implant showed effective antibacterial ability while promoting bone regeneration. Besides distal femur defect, the innovative scaffolds may also serve as an ideal biomaterial (e.g. dental implants) for other contaminated defects.

Long-term outcomes of osteotome sinus floor elevation without grafting in severely atrophic maxilla: A 10-year prospective study.

OBJECTIVE: The aim of the present study was to report 10-year results of osteotome sinus floor elevation (OSFE) without grafting severely atrophic maxilla (residual bone height ≤4 mm). MATERIALS AND METHODS: Patients undergoing OSFE without grafting and implant placement were included for 10-year examinations. Implant survival, complication-free survival, modified bleeding index (mBI), modified plaque index (mPI), pocket probing depth (PPD), peri-implant marginal bone loss (MBL), endo-sinus bone gain (ESBG) and mean cost of recurrence were evaluated. RESULTS: Overall, 23 patients with 35 implants attended 10-year examination. Cemented implant crowns or implant-supported fixed dental prostheses were delivered to the patients. Kaplan-Meier implant survival was 89.2% at implant level and 84.1% at patient level. Complication-free survival was 26.0% at patient level and 37.0% at implant level. The average complication-free survival time was 74.6 months (95% CI: 63.2-86.0 months) at implant level and 69.1 months (95% CI: 54.8-83.4 months) at patient level. The mBI, mPI, PPD, MBL and ESBG at 10-year follow-up were 0.91 ± 0.58, 0.48 ± 0.51, 2.94 ± 0.79 mm, 1.63 ± 0.83 mm and 2.72 ± 0.51 mm, respectively. The cost of managing recurrence was 43.6% of the initial cost of treatment. CONCLUSION: The results of the present study indicate that OSFE without grafting is a reliable treatment option in severely atrophic maxilla. Acceptable survival rate, stable MBL and ESBG could be achieved within 10 years. Low complication-free survival and high costs of recurrence management need to be considered.

Angulated screw-retained and cemented implant crowns following flapless immediate implant placement in the aesthetic region: A 1-year prospective cohort study.

PURPOSE: To compare the short-term clinical and radiographic outcomes of angulated screw-retained and cemented implant crowns following flapless immediate implant placement. MATERIALS AND METHODS: The study was designed as a prospective cohort study with 1-year follow-up. Eligible patients were divided into two groups according to restoration type: the angulated screw group (AG) and the cemented group (CG). Implant survival, marginal bone loss, mechanical complications, probing depth, bleeding on probing% and pink aesthetic score were evaluated. RESULTS: After 1 year of loading, the implant survival rate was 100% in both groups (AG, n = 23; CG, n = 20). A significantly lower bleeding on probing% was found in the AG than in the CG (11.6 ± 19.1% vs. 33.3 ± 33.8%, P = 0.04). No significant differences in marginal bone loss, probing depth and mechanical complication rates were found between the two groups (P = 0.53, 0.48, 0.41, respectively). The overall pink aesthetic score value was 8.96 ± 0.88 in the AG and 8.98 ± 0.62 in the CG at 1-year examination (P = 0.96). The percentage of excellent pink aesthetic scores (≥ 9) value increased from 48% at baseline to 83% at 1 year in the AG, and from 45% at baseline to 85% at 1 year in the CG. CONCLUSION: Based on the 1-year results, both treatment options provide high implant survival, a stable marginal bone level and excellent aesthetic outcomes in the short term. Angulated screw-retained crowns might benefit the long-term peri-implant conditions.

The responses of human gingival fibroblasts to magnesium-doped titanium.

The titanium (Ti) implant is widely used in implant dentistry; yet peri-implantitis has always been one of the most common and serious complications. Here, we demonstrated that magnesium-doping would be an effective way of enhancing the integration between implant surfaces and gingival tissues, which is critical to peri-implant health. The magnesium (2.76-6.35 at %) was immobilized onto the titanium substrate by a magnesium plasma immersion ion implantation (Mg-PIII) technique. Mg-PIII treatments did not alter surface topographies of the original titanium substrate but improved its hydrophilicity. The in vitro study including cell viability, adhesion, proliferation, migration, and real-time polymerase chain reaction assays disclosed improved adhesion, proliferation, migration, and extracellular matrix remodeling abilities of human gingival fibroblasts (HGFs) on the magnesium-doped titanium. The results of western blot suggested that the Mg-modified titanium induced the phosphorylation of AKT through the activation of PI3K. Our results revealed that magnesium-doping would potentially enhance soft tissue sealings by promoting cellular functions of HGFs in a dose-dependent manner, boding well for its applications on surfaces of implant necks in early peri-implant soft tissue integrations.

Ta-Coated Titanium Surface With Superior Bacteriostasis And Osseointegration.

BACKGROUND: Although tantalum (Ta)-based coatings have been proven to have good antibacterial activity, the underlying mechanism and in vivo biological performance remain unclear, which are essential for the clinical application of Ta-coated biomaterials as dental implants. PURPOSE: The main objective of this study is to investigate the antibacterial activity of Ta-modified titanium (Ti) implants against peri-implantitis-related microbes and the potential molecular mechanisms. METHODS: Fusobacterium nucleatum and Porphyromonas gingivalis were selected to evaluate the antibacterial activity and potential antibacterial mechanism of Ta modification. The in vivo biocompatibility of Ta-modified implants was also evaluated. RESULTS: The results showed that Ta-modified surface performed excellent antimicrobial activity against Fusobacterium nucleatum and Porphyromonas gingivalis. Micro galvanic might be formed between the incorporated Ta and the Ti base, which could consume the protons and result in decreased ATP synthesis and increased ROS generation. The gene expression of bacterial virulence factors associated with cellular attachment, invasion and viability as the target of ROS was downregulated. Importantly, in vivo biological studies showed that Ta modification significantly promoted the osseointegration of implants by stimulating the expression of bone-forming proteins. CONCLUSION: This study may provide some insights into clinical applications of Ta-coated Ti implants, especially in possibly infected situations.

[Effect of photodynamic therapy on interleukin in gingival crevicular fluid from patients receiving oral implantation].

PURPOSE: Photodynamic therapy (PDT) has been applied in treatment of peri-implantitis for its antimicrobial effects. The aim of the study was to evaluate the effects of a Denfotex PAD Light System's photodynamic therapy on prevention of peri-implantitis. METHODS: Twenty patients with implants in molar area were treated with photoactivated disinfection right after completion of suprastructures. The irradiation time was 30 seconds for mesial, distal, buccal and lingual/palatal sites respectively at a power output of 100mW. Gingival crevicular fluid (GCF) samples from these patients were obtained before photodynamic treatment, 2 weeks and 3 months after treatment. GCF was collected using paper points, and enzyme-linked immunosorbent assay (ELISA) was performed to determine the cytokine (IL-1ß, ΤΝF-α, IL-6 and ΙL-17) levels. The data were analyzed with SPSS 23.0 software package. RESULTS: ELISA showed IL-1ß and ΤΝF-α levels of all patients were decreased 2 weeks and 3 months after treatment. Reduction of IL-1ß, ΤΝF-α, IL-6 and IL-17 from 2 weeks to 3 months and from baseline to 3 months all showed a significant difference (P＜0.05). CONCLUSIONS: Denfotex PAD light system is effective in reducing peri-implant inflammatory mediators and can work as an effective treatment to prevent peri-implantitis.

Short versus longer implants with osteotome sinus floor elevation for moderately atrophic posterior maxillae: A 1-year randomized clinical trial.

PURPOSE: To compare the clinical, radiographic outcomes and patient satisfaction of short-6-mm implants and longer implants combined with osteotome sinus floor elevation (OSFE). MATERIALS AND METHODS: Two hundred and twenty-five patients with 225 implants were included and randomly assigned into three groups (each group: 75 implants) using randomizing table method: group 6 mm (6 mm implants alone), group 8 mm + O (8 mm implants + OSFE) and group 10 mm + O (10 mm implants + OSFE). Outcomes measures were as follows: implant survival, complication, resonance frequency analysis measurement, surgical time, bleeding on probing (BOP), pocket probing depth (PPD), modified plaque index (mPI), marginal bone loss (MBL) and patient satisfaction. RESULTS: The dropout rate was 3.6% at 1 year. Implant survival rates were 96%, 100% and 100% in group 6 mm, group 8 mm + O and group 10 mm + O, respectively. In group 6 mm, the survival rates of implants with diameter of 4.1 mm were 90% (27/30), while the survival rates of implants with diameter of 4.8 mm were 100% (42/42). The surgical time (min) in group 6 mm was significantly shorter than those in group 8 mm + O and group 10 mm + O (13.6 ± 2.2, 19.4 ± 3.7 and 18.3 ± 4.3, respectively, p = 0.03). No significant differences in ISQ values, BOP, PPD, mPI and MBL were found among three groups. Significant higher value of intra-operative discomfort was found in group 6 mm (p = 0.02). CONCLUSION: All treatment options provided acceptable clinical and radiographic results up to 1 year after loading. The current 1-year results must be confirmed by longer follow-ups of at least 5 years.

A study on the prevalence of dental anxiety, pain perception, and their interrelationship in Chinese patients with oral implant surgery.

BACKGROUND: Accumulating evidence has revealed that dental anxiety (DA) is associated with pain and patient satisfaction related to dental procedures. However, relevant reports are limited and inconsistent in oral implant patients. PURPOSE: The purpose of this study was to investigate the prevalence of dental anxiety, pain perception, and analyze their interrelationship in Chinese patients with oral implant surgery. MATERIALS AND METHODS: A cross-sectional study was performed according to the strengthening the reporting of observational studies in epidemiology (STROBE) guideline. Consecutive patients who received oral implant surgeries during February-March of 2018 in Shanghai Ninth People's Hospital were recruited. The modified dental anxiety scale and visual analog scale were used to evaluate the level of the patient's DA and pain perception. Multivariate logistic regression was applied to analyze the influence of DA on pain perception of patients during oral implant surgery. RESULTS: The prevalences of moderate and high preoperative DA were 66.6% and 11.9% in Chinese patients with oral implant surgery, respectively. Seven points eight percent of patients experienced pain perception during surgery. The result of multiple logistic regression showed that there was no significant influence of moderate preoperative DA (OR = 2.0, 95%CI: 0.5-8.2) on pain perception. However, a significant influence of high preoperative DA (OR = 6.4, 95%CI: 1.3-30.8) was found on pain perception of patients with oral implant surgery. Significant influences of moderate perioperative DA (OR = 5.0, 95%CI: 1.1-22.9) and high perioperative DA (OR = 8.7, 95%CI: 1.1-69.9) were also found on pain perception of patients during oral implant surgery. CONCLUSIONS: The results of the study indicated that DA was very common in Chinese patients with oral implant surgery. DA may increase pain perception of patients during oral implant surgery.

A novel semiautomatic segmentation protocol to evaluate guided bone regeneration outcomes: A pilot randomized, controlled clinical trial.

OBJECTIVES: The aims of this study were to (a) present a novel morphological contour interpolation (MCI) algorithm based method to evaluate grafted bone alterations following guided bone regeneration (GBR), (b) compare clinical and radiological outcomes of GBR with two different collagen membranes. MATERIALS AND METHODS: The data were retrieved from an ongoing randomized controlled trial. Patients were randomly allocated into two groups: (a) control group (CG): Bio-Gide (b) test group (TG): bovine dermis-derived collagen membrane. Cone beam computed tomography examinations were performed 1 week (T0) and 6 months after surgery (T1). PES/WES at T1, grafted bone volume and density changes from T0 to T1 were recorded. RESULTS: Thirty-six patients (16/20 in test/control group, respectively) were enrolled in the present study. Excellent inter-observer reliability (ICC ≥ 0.97) was revealed for repeated measurements using this method. Significant volumetric reduction of grafted bone were found in both groups (test group: from 0.60 to 0.39 cm3 , p < 0.01; control group: from 0.54 to 0.31 cm3 , p < 0.01). Mean bone density (gray-scale values) significantly increased from 305.12 to 456.69 in CG (p < 0.01). In TG, it slightly increased from 304.75 to 393.27 (p = 0.25). The mean PES/WES values were 13.84 (6.62/7.22) and 13.90 (6.70/7.20) for TG and CG, respectively. As for inter-group comparison, no significant differences of grafted bone volume change, density change and PES/WES were found between two groups. CONCLUSION: Within the limitations of this study, the novel MCI-based method is a reproducible tool to segment and visualize changes of grafted bone in 3D. Furthermore, both collagen membranes could be used as a barrier membrane for GBR in humans.

Proximal Contact Alterations Between Implant-Supported Restorations and Adjacent Natural Teeth in the Posterior Region: A 1-Year Preliminary Study.

PURPOSE: The aim of this study was to evaluate the proximal contact alterations between implant-supported restorations and adjacent natural teeth with the passage of time. In addition, potential factors influencing proximal contact loss were also evaluated. MATERIALS AND METHODS: Patients in need of implant-supported restorations in the posterior region were included. Proximal contact was divided into the following three groups: tight (group T), appropriate (group A), and open (group O). It was judged by dental floss (OralB, Essentialfloss) at restoration insertion and 1-year follow-up. In addition, patients' age, sex, implant sites, restoration type, retention type, and parafunction were recorded. RESULTS: At 1-year follow-up, 74 patients with 144 proximal contacts were included. After 1-year follow-up, the proximal contact loss rate was 24.3%, and 45.1% of proximal contacts did not show any alterations. The proximal contact loss rates in group T at baseline were significantly lower than those in group A at baseline (12.9% and 32.9%, respectively; P = .03). The proximal contact loss rates in the mandible were significantly higher than those in the maxilla (37.2% and 9.1%, respectively; P < .01). Other variables did not show a significant effect on proximal contact loss. CONCLUSION: Based on the current evidence, the proximal contact loss between implant-supported restorations and the adjacent teeth was frequent in the short term. It is helpful to reduce the proximal contact loss rate in the short term by making the proximal contact slightly tense at restoration insertion. Evaluation of proximal contact should be monitored carefully, especially in the mandible.

Endo-sinus bone formation after transalveolar sinus floor elevation without grafting with simultaneous implant placement: Histological and histomorphometric assessment in a dog model.

AIM: To evaluate endo-sinus new bone formation and implant osseointegration after transalveolar sinus floor elevation (TSFE) and simultaneous implant placement without any grafting materials and to investigate the influence of implant surface modification on bone healing process under this circumstance. MATERIALS AND METHODS: Transalveolar sinus floor elevation and simultaneous implant placement were conducted bilaterally on 12 Labrador dogs. No grafting materials were used during surgery. Implants with two different surfaces (SLA and SLActive) were placed in a split-mouth design. The animals were sacrificed 4, 8 and 24 weeks after surgery for histological and histomorphometric assessments. Bone-to-implant contact (BIC%), alveolar bone height (ABH) and the percentages of mineralized bone (MB%) in the area of interest were analysed. The probing depth (PD) and bleeding on probing (BOP) were also assessed to describe peri-implant health conditions. RESULTS: Sprouts of new bone in direct contact with implant surface were seen in the elevated area at every time point. Newly formed woven bone under sinus membrane was visible. SLActive implants exhibited favourable results compared with SLA implants regarding ABH at 4 weeks and BIC% at 4 and 8 weeks. Sites with BOP positive could be observed in both groups at any time point. No newly formed bone can be found on the implant apex with either SLA or SLActive surfaces at any time point. CONCLUSIONS: Spontaneous new bone formation from the parent bone walls could be observed after TFE without any grafting materials. No clear evidence of bone formation from the Schneiderian membrane could be found. Even though there were trends for quicker bone response of SLActive implants, this study failed to show the absolute advantage of SLActive in achieving endo-sinus bone formation.