Publications by authors named "Michel Dard"

103 Publications

One-Year Results Assessing the Performance of Prosthetic Rehabilitations in the Posterior Maxilla Supported by 4-mm Extrashort Implants Splinted to 10-mm Implants: A Prospective Case Series.

Int J Oral Maxillofac Implants 2021 Mar-Apr;36(2):371-378

Purpose: The aim of this study was to evaluate the survival and success rates of oral rehabilitations in a shortened maxillary dental arch and expanded maxillary sinus with 4-mm extrashort implants splinted to longer ones.

Materials And Methods: One 10-mm and one/two extrashort 4-mm titanium-zirconium SLActive tissue-level dental implants were inserted into 11 patients with limited vertical bone availability due to an expanded maxillary sinus antrum. Immediately and 6 months after insertion, implant stability resonance frequency analysis (RFA) values were assessed with an Osstell device. Splinted crowns combining 4- and 10-mm implants were supplied to all 11 cases.

Results: In 10 cases, the bone quality was type III, and in one case, type IV. Among 17 4-mm and 11 10-mm implants, the median RFA values were 61 (interquartile ranges [IQR]: 59 to 64) and 66 (IQR: 64 to 72). One 4-mm implant failed to osseointegrate and was removed. After 6 months of healing, secondary-stability measurements of 16 of the remaining 4-mm implants increased to 68 (IQR: 62 to 72) and of 10-mm implants to 78 (IQR: 77 to 80). After 1 year, all (11/11) oral rehabilitations supported by 10-mm (11/11) and 4-mm (16/16) implants were functional. The medians and IQRs of the probing depths (median: 2.8 mm, IQR: 2.3 to 3.1 mm vs median: 2.9 mm, IQR: 2.4 to 3.1 mm) and the crestal bone loss (median: 0.75 mm, IQR: 0 to 0.9 mm vs median: 0.22 mm, IQR: 0 to 0.4 mm) for the 10-mm and 4-mm implants, respectively, were similar.

Conclusion: Rehabilitations with splinted crowns combining 4- and 10-mm implants demonstrated a favorable 1-year performance in a shortened maxillary dental arch.
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http://dx.doi.org/10.11607/jomi.8645DOI Listing
April 2021

The Use of 4-mm Implants Splinted to 10-mm Implants for Replacement of Multiple Missing Teeth in the Posterior Maxilla Region with Expanded Maxillary Sinus. An Observational Cases Series: Patient Characteristics and Preliminary Results.

Int J Periodontics Restorative Dent 2021 Mar-Apr;41(2):261-268

This study aimed to rehabilitate shortened maxillary dental arch with splinted crowns by connecting ultra-short implants with longer ones. In the posterior maxilla of 11 patients, one 10-mm (n = 11) and one or two ultra-short 4-mm (n = 17) dental implants were inserted. The insertion torque was lower than 20 Ncm in 55% of the 10-mm implants and in 94% of the 4-mm implants ( > .05). Median (range) implant stability quotients at the time of insertion and after 6 months were 61 (14 to 72) and 68 (51 to 79), respectively, for 4-mm implants, and 66 (52 to 78) and 78 (60 to 83), respectively, for 10-mm implants ( < .05). One 4-mm implant failed to integrate. All patients were restored with splinted metal-ceramic crowns connecting 4- and 10-mm implants. Median (range) clinical crown/implant ratios of 4-mm and 10-mm implants were 2.79 (1 to 3.66) and 1.06 (0.85 to 1.46), respectively ( < .05). Six months after prosthetic rehabilitation, the median (range) crestal bone loss was 0.3 mm (-0.7 to 1.7 mm) for 4-mm implants and was 0.5 mm (-0.8 to 3.5 mm) for 10-mm implants ( > .05). Splinted crowns combining 4- and 10-mm implants may contribute to a better force distribution in the treatment with ultra-short implant-supported prosthesis in the posterior maxilla.
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http://dx.doi.org/10.11607/prd.4389DOI Listing
April 2021

Influence of implant location on titanium-zirconium alloy narrow-diameter implants: A 1-year prospective study in smoking and nonsmoking populations.

J Prosthet Dent 2021 Feb 4. Epub 2021 Feb 4.

Professor, State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China. Electronic address:

Statement Of Problem: Titanium-zirconium (Ti-Zr) alloy (Roxolid) narrow-diameter implants (NDIs) have been widely used for implant-supported prostheses in anterior and posterior regions in the jaws. However, the relationship between implant location and clinical outcome remains unclear.

Purpose: The purpose of this clinical study was to evaluate and compare the clinical and radiographic outcomes of NDIs placed in different regions of the jaws in both smokers and nonsmokers.

Material And Methods: Eighty-four participants scheduled to receive NDIs for tooth rehabilitation were included, and the inserted NDIs were divided into 3 groups depending on their locations: implants used to restore anterior teeth, implants used to restore premolars, and implants used to restore molars. Crestal bone loss (CBL), implant survival and success rates, bleeding on probing (BOP), and pocket probing depth (PPD) were evaluated 6 and 12 months after implant loading (α=.017 for implant survival and success rates after Bonferroni correction, α=.05 for other parameters).

Results: Statistical analysis of 6- and 12-month CBL of all participants presented no statistically significant difference among the 3 groups. For smokers, the molar group presented significantly more CBL than the premolar group (0.90 ±0.94 versus 0.16 ±0.27 mm, P=.027) at the 6-month examination. The implant survival rates were 95.65%, 100%, and 100% for anterior, premolar, and molar regions, respectively (P=.283). No statistically significant difference was observed regarding periodontal parameters (P>.05).

Conclusions: Implant location has no influence on the clinical and radiographic parameters of Ti-Zr NDIs placed in a nonsmoking population. However, the combination of posterior location and smoking may induce higher risk of crestal bone loss. Caution should be taken when restoring molars for smokers with NDIs.
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http://dx.doi.org/10.1016/j.prosdent.2020.09.051DOI Listing
February 2021

Effect of enamel matrix derivative liquid combined with synthetic bone substitute on bone regeneration in a rabbit calvarial model.

Clin Oral Investig 2021 Feb 1;25(2):547-554. Epub 2020 Aug 1.

Department of Oral & Maxillofacial Surgery, School of Dentistry, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.

Objectives: This study aimed to verify the effectiveness of EMD-liquid in combination with a synthetic bone substitute in a rabbit calvarial model.

Material And Methods: Four 7-mm outer diameter circular slits were created in the calvaria of 10 New Zealand white rabbits, and polycarbonate cylinders were inserted into the slits. Two experimental groups were established: (1) EMD-liquid + bone substitute (Osteon III®; biphasic calcium phosphate (BCP), β-TCP/HA = 40:60) and (2) saline + bone substitute (Osteon III®; BCP). The cylinders were filled with saturated graft materials and covered with polycarbonate caps. Micro-CT and histomorphometric evaluation were conducted.

Results: In the histomorphometric analysis, new bone formation was significantly higher in the bone substitute (BS) + EMD-liquid group than in the BS only group at both 5 and 10 weeks (p < 0.01). There were statistically significant differences in the material area between the bone substitute and bone substitute + EMD-liquid groups at only 5 weeks (p < 0.05). The BS + EMD-liquid group demonstrated reduced material area to a greater extent. In micro-CT analysis, the BS + EMD-liquid group (27.04 ± 8.06 at 5 weeks, 28.49 ± 9.22 at 10 weeks) showed a significantly higher percentage of mineralized tissue volume at both 5 and 10 weeks (p < 0.05) than the BS only group.

Conclusion: EMD-liquid enhances new bone formation when combined with BCP bone substitute in an animal model. Moreover, the EMD-liquid + BS has significantly lesser material area than BS alone, indicating accelerated graft degradation. Further studies on types of graft materials are required to verify the effect of EMD-liquid and to optimize its regenerative potential.

Clinical Relevance: This study suggests that EMD-liquid may have beneficial effect on bone regeneration with synthetic bone substitute.
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http://dx.doi.org/10.1007/s00784-020-03473-4DOI Listing
February 2021

Comparing the Bone Healing After Cold Ablation Robot-Guided Er:YAG Laser Osteotomy and Piezoelectric Osteotomy-A Pilot Study in a Minipig Mandible.

Lasers Surg Med 2021 03 11;53(3):291-299. Epub 2020 Jun 11.

Department of Cranio-Maxillofacial Surgery, University Hospital of Basel, Spitalstrasse 21, Basel, 4031, Switzerland.

Background And Objective: To take major advantage of erbium-doped yttrium aluminium garnet (Er:YAG) lasers in osteotomy-like freedom of cutting geometries and high accuracy-the integration and miniaturization of the robot, laser, and navigation technology was tried and applied to minipigs. The investigators hypothesized laser osteotomy would render acceptable bone healing based on the intraoperative findings and postoperative cut surface analysis.

Study Design/materials And Methods: We designed and implemented a comparative bone-cutting surgery in the minipig mandible with a cold ablation robot-guided Er:YAG laser osteotome (CARLO) and a piezoelectric (PZE) osteotome. The sample was composed of different patterns of defects in the mandibles of six grown-up female Goettingen minipigs. The predictor variable was Er:YAG osteotomy and PZE osteotomy. The outcome variable was the cut surface characteristics and bone healing at 4 and 8 weeks postoperatively. Descriptive and qualitative comparison was executed.

Results: The sample was composed of four kinds of bone defects on both sides of the mandibles of six minipigs. We observed more bleeding during the operation, open-cut surfaces, and a faster healing pattern with the laser osteotomy. There was a possible association between the intraoperative findings, postoperative cut surface analysis, and the bone healing pattern.

Conclusions: The results of this study suggest that characteristic open-cut surfaces could explain favorable bone healing after laser osteotomy. Future studies will focus on the quantification of the early healing characteristics after laser osteotomy, its diverse application, and the safety feature. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
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http://dx.doi.org/10.1002/lsm.23281DOI Listing
March 2021

A decade of the socket-shield technique: a step-by-step partial extraction therapy protocol.

Int J Esthet Dent 2020 ;15(2):212-225

Ten years have passed since Hürzeler and coworkers first introduced the socket-shield technique. Much has developed and evolved with regard to partial extraction therapy, a collective concept of utilizing the patient's own tooth root to preserve the periodontium and peri-implant tissue. The specifications, steps, instrumentation, and procedures discussed in this article are the result of extensive experience in refining the socket-shield technique as we know it today. A repeatable, predictable protocol is requisite to providing tooth replacement in esthetic dentistry. Moreover, a standardized protocol provides a better framework for clinicians to report data relating to the technique with procedural consistency. This article aims to illustrate a reproducible, step-by-step protocol for the socket-shield technique at immediate implant placement and provisionalization for single-rooted teeth.
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June 2020

Evaluation of the Treatment of Partially Edentulous Patients With Bone Level Tapered Implants: 24-Month Clinical and Radiographic Follow-Up.

J Oral Implantol 2020 Aug;46(4):407-413

Institute Straumann AG, Basel, Switzerland.

The aim of this case series was to assess, over a period of 24 months, the clinical and radiographic outcomes in partially edentulous patients receiving bone-level tapered implants. In total, 33 partially edentulous patients and 50 implants were evaluated. Patients received single or multiple implants in the posterior maxilla. Clinical and radiographic measurements of vertical bone levels were assessed at surgery, at loading, and 6, 12, and 24 months after surgery. The success and survival rates of the implants were also evaluated. Within the 24-month follow-up, only 1 implant failed (2.0%). Other biological or technical complications were not observed. The mean insertion torque was 34 ± 5.3 Ncm. Bone-level changes of 0.35 ± 0.23 mm were found between surgery and 12 months after surgery, and changes of 0.03 ± 0.05 mm were found between 12 months and 24 months after surgery. The overall change from surgery to 24 months after implant placement was 0.38 ± 0.24 mm. Most of the bone loss occurred between surgery and 3 months (0.28 ± 0.19 mm; P < .001); thereafter, the loss was minimal and statistically nonsignificant. Bone-level tapered implants yielded a high survival and success rate with minimal bone-level changes. Tapered implants could be considered as a predictable treatment option for partially edentulous patients with different types of bone qualities and loading protocols.
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http://dx.doi.org/10.1563/aaid-joi-D-19-00024DOI Listing
August 2020

Maxillary Sinus Floor Elevation Surgery With BioOss Mixed With Enamel Matrix Derivative: A Human Randomized Controlled Clinical and Histologic Study.

J Oral Implantol 2020 Oct;46(5):507-513

Preclinical & Translational Research, Institut Straumann AG, Basel, Switzerland.

Xenograft bone substitutes are commonly used to increase bone volume and height in the deficient posterior maxilla. The addition of enamel matrix derivate (Emdogain) could increase the efficiency of the bone healing process. The aim of this prospective randomized, controlled split-mouth design study was to compare the percentage of newly formed bone in sinus floor augmentation with deproteinized bovine bone mineral with or without the addition of enamel matrix derivative after 6 months of healing. Sixteen bilateral sinus floor augmentation procedures were performed. Deproteinized bovine bone mineral combined with enamel matrix derivative (test) and deproteinized bovine bone mineral alone (control) groups were randomly allocated within each patient. Six months after augmentation and concurrent to implant placement, bone biopsies were taken for histomorphometric analysis. Additionally, implant survival and peri-implant bone levels were radiographically assessed at baseline and 24 months after functional loading. Histomorphometric analysis revealed a significantly higher amount of newly formed bone in the test group compared with the control group (22.6% and 15.5%, respectively; P = .033). No significant differences in the amount of remaining graft or connective tissue was found. Enamel matrix derivative added to deproteinized bovine bone mineral particles significantly increased new bone formation in sinus lift procedures in edentulous or partially edentulous patients with deficient bilateral posterior alveolar ridges requiring augmentation for implant placement.
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http://dx.doi.org/10.1563/aaid-joi-D-19-00119DOI Listing
October 2020

Evaluation of a novel dog animal model for peri-implant disease: clinical, radiographic, microbiological and histological assessment.

Clin Oral Investig 2020 Sep 8;24(9):3121-3132. Epub 2020 Jan 8.

Institute of Periodontology, Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal.

Objective: To assess longitudinal peri-implant tissue evaluation in a plaque compromised ligature free dog model, clinically, radiographically, microbiologically and histologically.

Materials And Methods: Six beagle mandibular premolars and first molars were extracted. Plaque accumulated for 16 weeks. Two implants were placed per hemi-mandible. For 17 weeks, control implants (CI) in one hemi-mandible were brushed daily; test implants (TI) in the other were not. These parameters were then assessed: clinically, probing depth (PD), bleeding-on-probing (BOP), presence of plaque (PP) and clinical attachment level (CAL); radiographically, marginal bone level; microbiologically, counts for Streptococcus spp., Fusobacterium spp., Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and total bacterial load. At week 17, histomorphometric analysis was performed (MM-ISH (mucosal margin-implant shoulder); ISH-fBIC (implant shoulder-first bone-to-implant contact); MM-aJE (mucosal margin-apical area junctional epithelium); MM-aINF (mucosal margin-apical limit of the inflammatory infiltrate); %INF (percentage of inflammatory infiltrate)).

Results: At week 17, TI had significant increased PD, BOP, PP and CAL versus baseline. All clinical variables presented intergroup differences. There was no intergroup difference for radiographic bone loss (p > 0.05). Total bacteria, Fusobacterium spp., A. actinomycetemcomitans and P. gingivalis had intergroup differences. There was no statistically significant intergroup difference for ISH-fBIC.

Conclusions: Longitudinal microbiology evaluation detected a shift period. Final intergroup microbiological differences were the basis of W17 clinical intergroup differences, with higher values in TI. Microbiological and clinical changes detected in peri-implant tissues were compatible with onset of peri-implant disease. Despite histological inflammatory intergroup difference, no histological or radiographic intergroup bone loss was detected.

Clinical Relevance: This study set-up describes a valuable method for generating "true" early peri-implant defects without mechanical trauma.
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http://dx.doi.org/10.1007/s00784-019-03186-3DOI Listing
September 2020

Image analysis of immediate full-arch prosthetic rehabilitations guided by a digital workflow: assessment of the discrepancy between planning and execution.

Int J Implant Dent 2019 Jul 15;5(1):26. Epub 2019 Jul 15.

Institut Straumann AG, Peter Merian-Weg 12, 4052, Basel, Switzerland.

Background: A dentition with adequate function and esthetics is essential for the well-being and quality of life. A full implant-retained fixed prosthetics is an ideal solution for fully edentulous arch, however requires complex planning, surgical, and prosthetic procedure. With the help of digital workflow, it becomes a predictable and fast solution for the dentists and the patients. This retrospective study analyzed the most advanced surgical approach in full-arch rehabilitation with dental implants and immediate loading using digital workflow.

Methods: Patient records of fully edentulous jaws treated in four clinical centers in Warsaw, Poland, were evaluated. Computer-assisted planning and surgical template fabrication were done using the planning software coDiagnostiX™, based on a pre-op cone beam computed tomography (CBCT) and scanned data of a plaster model. A post-op CBCT was acquired after the placement of four to six implants by the guided system. The influence of different surgical variables on the discrepancy between planning and execution was analyzed, together with the biomechanical indices.

Results: A total of nine patient records were selected of 12 edentulous jaws treated with 62 implants. The overall mean three-dimensional (3D) offset at the implant base was 1.60 mm, at the tip 1.86 mm. The mean angle of deviation was 4.89°, the mean implant stability quotient (ISQ) 70.42, and the insertion torque 35.58 Ncm. The 3D offsets were influenced by the gender of the patient, treated jaw, the diameter, and length of the implant. The angle of deviation was affected only by the treated jaw. Insertion torque was influenced by the treated jaw, the age of the patient, the length of the implant, tooth type, and the side of the jaw.

Discussion: Bone quality of the patient and implant preparation procedure influenced the discrepancy between the planning and the execution of the digitally guided implant placement. Dense bone-mandible, posterior area, young age, and man-and multiple preparations of the implant bed-wider and longer implant-could be suggested as risk factors.

Conclusion: Digital workflow successfully enabled the immediate full-arch rehabilitation with a predictable outcome by different surgeons in multiple centers.
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http://dx.doi.org/10.1186/s40729-019-0179-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6626765PMC
July 2019

Osseointegration of Superhydrophilic Implants Placed in Defect Grafted Bones.

Int J Oral Maxillofac Implants 2019 March/April;34(2):443–450. Epub 2019 Jan 31.

Purpose: Only limited information on the effect of implant surface hydrophilicity in conjunction with simultaneous bone augmentation is available. In this study, new bone growth around implants with a superhydrophilic modSLA (SLActive) and hydrophobic SLA (SLA) surface were compared in circumferential defects when grafted in conjunction with mineralized cancellous bone allograft (MCBA, maxgraft) or sintered bovine bone mineral (SBBM, cerabone).

Materials And Methods: The osseointegration and bone formation in circumferential defects in minipig mandibles around Straumann Roxolid, Ø 3.3 mm, length 8 mm; either SLA or SLActive, were evaluated. Following implant placement, the 2-mm circumferential defects around the implants were filled with MCBA or SBBM. Distance from implant shoulder to first bone-to-implant contact (f-BIC), percentage of bone-to-implant contact (BIC), and bone aggregate percentage (amount of new bone and remaining graft) within the defect area were evaluated after 8 weeks of healing.

Results: In the SBBM group, lingual fBIC and buccal BIC were significantly lower for SLA (mean -0.404 ± 0.579 mm for modSLA versus -1.191 ± 0.814 mm for SLA, P = .021 and mean 62.61% ± 9.49% for modSLA versus 34.67% ± 24.41% for SLA, P = .047, respectively). Bone aggregate percentage was significantly higher for modSLA versus SLA implants in SBBM (77.84% ± 6.93% versus 64.49% ± 13.12%; P = .045). The differences between implant surfaces in MCBA showed a similar trend but were less pronounced than in the SBBM group and did not reach a statistically significant level.

Conclusion: The results suggest that implants with a superhydrophilic modSLA surface are more conducive to faster osseointegration even in conjunction with simultaneous bone grafting procedures.
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http://dx.doi.org/10.11607/jomi.7172DOI Listing
May 2019

Recombinant amelogenin regulates the bioactivity of mouse cementoblasts in vitro.

Int J Oral Sci 2018 05 9;10(2):15. Epub 2018 May 9.

Department of Orthodontics, Oral Biology Laboratory, Faculty of Dentistry, University of Bonn, Bonn, Germany.

Amelogenin (AMG) is a cell adhesion molecule that has an important role in the mineralization of enamel and regulates events during dental development and root formation. The purpose of the present study was to investigate the effects of recombinant human AMG (rhAMG) on mineralized tissue-associated genes in cementoblasts. Immortalized mouse cementoblasts (OCCM-30) were treated with different concentrations (0.1, 1, 10, 100, 1000, 10,000, 100,000 ng · mL) of recombinant human AMG (rhAMG) and analyzed for proliferation, mineralization and mRNA expression of bone sialoprotein (BSP), osteocalcin (OCN), collagen type I (COL I), osteopontin (OPN), runt-related transcription factor 2 (Runx2), cementum attachment protein (CAP), and alkaline phosphatase (ALP) genes using quantitative RT-PCR. The dose response of rhAMG was evaluated using a real-time cell analyzer. Total RNA was isolated on day 3, and cell mineralization was assessed using von Kossa staining on day 8. COL I, OPN and lysosomal-associated membrane protein-1 (LAMP-1), which is a cell surface binding site for amelogenin, were evaluated using immunocytochemistry. F-actin bundles were imaged using confocal microscopy. rhAMG at a concentration of 100,000 ng · mL increased cell proliferation after 72 h compared to the other concentrations and the untreated control group. rhAMG (100,000 ng · mL) upregulated BSP and OCN mRNA expression levels eightfold and fivefold, respectively. rhAMG at a concentration of 100,000 ng · mL remarkably enhanced LAMP-1 staining in cementoblasts. Increased numbers of mineralized nodules were observed at concentrations of 10,000 and 100,000 ng · mL rhAMG. The present data suggest that rhAMG is a potent regulator of gene expression in cementoblasts and support the potential application of rhAMG in therapies aimed at fast regeneration of damaged periodontal tissue.
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http://dx.doi.org/10.1038/s41368-018-0010-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5966809PMC
May 2018

Effect of Obesity or Metabolic Syndrome and Diabetes on Osseointegration of Dental Implants in a Miniature Swine Model: A Pilot Study.

J Oral Maxillofac Surg 2018 Aug 1;76(8):1677-1687. Epub 2018 Mar 1.

Associate Professor, Section of Oral, Diagnostic and Rehabilitation Sciences, College of Dental Medicine, Columbia University, New York, NY; and Global Medical Director, Straumann Group, Basel, Switzerland.

Purpose: The increasing prevalence of obesity or metabolic syndrome (O/MS) and type 2 diabetes mellitus (DM) remains a global health concern. Clinically relevant and practical translational models mimicking human characteristics of these conditions are lacking. This study aimed to demonstrate proof of concept of the induction of stable O/MS and type 2 DM in a Göttingen minipig model and validate both of these disease-adjusted Göttingen minipig models as impaired healing models for the testing of dental implants.

Materials And Methods: Nine minipigs were split into 3 groups-control (normal diet), obese (cafeteria diet), and diabetic (cafeteria diet plus low-dosage streptozotocin)-followed by placement of dental implants. Inflammatory markers including tumor necrosis factor α, C-reactive protein, and cortisol were recorded for each study group. Removal torque was measured, and histomorphometric analysis (bone-to-implant contact and bone area fraction occupancy) was performed.

Results: O/MS pigs showed, on average, a 2-fold increase in plasma C-reactive protein (P < .05) and cortisol (P < .09) concentrations compared with controls; DM pigs showed, on average approximately, a 40-fold increase in plasma tumor necrosis factor α levels (P < .05) and a 2-fold increase in cortisol concentrations (P < .05) compared with controls. The impact of O/MS and DM on implants was determined. The torque to interface failure was highest in the control group (200 N-cm) and significantly lower in the O/MS (90 N-cm) and DM (60 N-cm) groups (P < .01). Bone formation around implants was significantly greater in the control group than in the O/MS and DM groups (P < .02).

Conclusions: Both O/MS and DM minipigs express a human-like disease phenotype, and both presented bone-healing impairment around dental implants. Our finding of no significant difference between type 2 DM and O/MS in bone formation around implants provides evidence that further investigation of the impact of O/MS is warranted.
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http://dx.doi.org/10.1016/j.joms.2018.02.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6064394PMC
August 2018

Hydoxyapatite/beta-tricalcium phosphate biphasic ceramics as regenerative material for the repair of complex bone defects.

J Biomed Mater Res B Appl Biomater 2018 08 20;106(6):2493-2512. Epub 2017 Dec 20.

Department of Oral, Biological & Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver V6T 1Z3, Canada.

Bone is a composite material composed of collagen and calcium phosphate (CaP) mineral. The collagen gives bone its flexibility while the inorganic material gives bone its resilience. The CaP in bone is similar in composition and structure to the mineral hydroxyapatite (HA) and is bioactive, osteoinductive and osteoconductive. Therefore synthetic versions of bone apatite (BA) have been developed to address the demand for autologous bone graft substitutes. Synthetic HA (s-HA) are stiff and strong, but brittle. These lack of physical attributes limit the use of synthetic apatites in situations where no physical loading of the apatite occurs. s-HA chemical properties differ from BA and thus change the physical and mechanical properties of the material. Consequently, s-HA is more chemically stable than BA and thus its resorption rate is slower than the rate of bone regeneration. One solution to this problem is to introduce a faster resorbing CaP, such as β-tricalcium phosphate (β-TCP), when synthesizing the material creating a biphasic (s-HA and β-TCP) formulation of calcium phosphate (BCP). The focus of this review is to introduce the major differences between BCP and biological apatites and how material scientists have overcome the inadequacies of the synthetic counterparts. Examples of BCP performance in vitro and in vivo following structural and chemical modifications are provided as well as novel ultrastructural data. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2493-2512, 2018.
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http://dx.doi.org/10.1002/jbm.b.34049DOI Listing
August 2018

Exercise-induced irisin in bone and systemic irisin administration reveal new regulatory mechanisms of bone metabolism.

Bone Res 2017 21;5:16056. Epub 2017 Feb 21.

Division of Oral Biology, Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA 02111, USA.

Irisin is a polypeptide hormone derived from the proteolytic cleavage of fibronectin-type III domain-containing 5 (FNDC5) protein. Once released to circulation upon exercise or cold exposure, irisin stimulates browning of white adipose tissue (WAT) and uncoupling protein 1 (UCP1) expression, leading to an increase in total body energy expenditure by augmented UCP1-mediated thermogenesis. It is currently unknown whether irisin is secreted by bone upon exercise or whether it regulates bone metabolism . In this study, we found that 2 weeks of voluntary wheel-running exercise induced high levels of FNDC5 messenger RNA as well as FNDC5/irisin protein expression in murine bone tissues. Increased immunoreactivity due to exercise-induced FNDC5/irisin expression was detected in different regions of exercised femoral bones, including growth plate, trabecular bone, cortical bone, articular cartilage, and bone-tendon interface. Exercise also increased expression of osteogenic markers in bone and that of UCP1 in WAT, and led to bodyweight loss. Irisin intraperitoneal (IP) administration resulted in increased trabecular and cortical bone thickness and osteoblasts numbers, and concurrently induced UCP1 expression in subcutaneous WAT. Lentiviral FNDC5 IP administration increased cortical bone thickness. studies in bone cells revealed irisin increases osteoblastogenesis and mineralization, and inhibits receptor activator of nuclear factor-kB ligand (RANKL)-induced osteoclastogenesis. Taken together, our findings show that voluntary exercise increases irisin production in bone, and that an increase in circulating irisin levels enhances osteogenesis in mice.
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http://dx.doi.org/10.1038/boneres.2016.56DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5605767PMC
February 2017

Overexpression of MiR-335-5p Promotes Bone Formation and Regeneration in Mice.

J Bone Miner Res 2017 Dec 28;32(12):2466-2475. Epub 2017 Aug 28.

Division of Oral Biology, Tufts University School of Dental Medicine, Boston, MA, USA.

MicroRNAs (miRNAs) and the Wnt signaling pathway play critical roles in regulating bone development and homeostasis. Our previous study revealed high expression of miR-335-5p in osteoblasts and hypertrophic chondrocytes in mouse embryos and the ability of miR-335-5p to promote osteogenic differentiation by downregulating Wnt antagonist Dickkopf-1 (DKK1). The purpose of this study was to investigate the effects of miR-335-5p constitutive overexpression on bone formation and regeneration in vivo. To that end, we generated a transgenic mouse line specifically overexpressing miR-335-5p in osteoblasts lineage by the osterix promoter and characterized its bone phenotype. Bone histomorphometry and μCT analysis revealed higher bone mass and increased parameters of bone formation in transgenic mice than in wild-type littermates. Increased bone mass in transgenic mice bones also correlated with enhanced expression of osteogenic differentiation markers. Upon osteogenic induction, bone marrow stromal cells (BMSCs) isolated from transgenic mice displayed higher mRNA expression of osteogenic markers than wild-type mice BMSCs cultures. Protein expression of Runx2 and Osx was also upregulated in BMSC cultures of transgenic mice upon osteogenic induction, whereas that of DKK1 was downregulated. Most important, BMSCs from transgenic mice were able to repair craniofacial bone defects as shown by μCT analysis, H&E staining, and osteocalcin (OCN) immunohistochemistry of newly formed bone in defects treated with BMSCs. Taken together, our results demonstrate constitutive overexpression of miR-335-5p driven by an osterix promoter in the osteoblast lineage induces osteogenic differentiation and bone formation in mice and support the potential application of miR-335-5p-modified BMSCs in craniofacial bone regeneration. © 2017 American Society for Bone and Mineral Research.
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http://dx.doi.org/10.1002/jbmr.3230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5732062PMC
December 2017

Oral health-related quality of life in subjects with implant-supported prostheses: A systematic review.

J Dent 2017 Oct 5;65:22-40. Epub 2017 Aug 5.

Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.

Objectives: The aim of the present study was to review the current literature relating to the impact of dental implants on oral health-related quality of life (OHRQoL) in edentulous or partially dentate patients.

Data/sources: Systematic literature searches were performed in the PubMed, EMBASE, and Cochrane Library databases, using high level MeSH terms. The searches were limited to studies published in English from 1960 to June 11, 2017, reporting OHRQoL outcomes using validated instruments, and having enrolled at least 50 patients.

Study Selection: After removal of duplicates, a total of 2827 unique hits were identified. After title, abstract, and full text screening, 63 articles were included in the review presenting findings of 55 individual studies. The provision of implant-supported dentures was associated with a significant increase in OHRQoL in partially dentate and in edentulous patients, with the magnitude of achieved improvement typically being greater for implant-supported dentures than with conventional ones. Furthermore, OHRQoL impairment prior to treatment was strongly associated with OHRQoL improvement.

Conclusion: For partially dentate patients, there is not enough evidence that implant-supported FDP are superior in terms of OHRQoL than conventional FDP, but moderate evidence suggests that implant-supported FDP perform better than conventional RDP. In edentulous patients, evidence suggests that only if OHRQoL at baseline is highly impaired and patients request implant treatment, IOD are superior than CD in terms of treatment-induced OHRQoL improvement.

Clinical Significance: Patients can be informed that implant treatment is usually related to a significant improvement in OHRQoL. However, improvement is not necessarily higher than for conventional prosthodontic treatments but depends on patient's clinical and psychosocial characteristics.
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http://dx.doi.org/10.1016/j.jdent.2017.08.003DOI Listing
October 2017

Effect of enamel matrix derivative on the angiogenic behaviors of human umbilical vein endothelial cells on different titanium surfaces.

Dent Mater J 2017 Jul 30;36(4):381-386. Epub 2017 May 30.

Division of Conservative Dentistry and Periodontology, School of Dentistry, Medical University of Vienna.

Angiogenesis play a crucial role in the regeneration of hard and soft tissue around dental titanium (Ti) implant. Enamel matrix derivative (EMD) promotes tissue regeneration and stimulates angiogenesis but its effect on the angiogenesis on Ti surfaces was never investigated. The effect of EMD on the angiogenic activity of endothelial cells cultured on pre-treated smooth Ti (PT), acidetched (A), coarse-grit blasted and acid-etched (SLA) surfaces and tissue culture plastic (TCP) in the presence or absence of EMD was investigated. EMD inhibited the proliferation/viability of human umbilical vein endothelial cells (HUVECs) growing on A and SLA Ti surfaces. EMD induced an increase in the expression of all these genes in HUVECs grown on SLA surface but not on other surfaces. Summarizing, our data show that EMD influences proliferation and expression of angiogenesis associated gene in HUVECs grown on moderately rough SLA surfaces, suggesting that EMD might promote angiogenesis following implantation.
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http://dx.doi.org/10.4012/dmj.2016-212DOI Listing
July 2017

Clinical Performance of Narrow-Diameter Titanium-Zirconium Implants: A Systematic Review.

Implant Dent 2017 Apr;26(2):316-323

*Clinical Instructor, Department of Oral Implantology, Faculty of Dental Surgery, University of Nantes, Nantes, France; Associate Professor, Department of Periodontology, Faculty of Dental surgery, (Inserm U791/UIC 11) CHU de Nantes, France. †Clinical Instructor, Department of Oral Implantology, Faculty of Dental Surgery, University of Nantes, Nantes, France. ‡Adjunct Assistant Professor, Department of Periodontology and Implant Dentistry, College of Dentistry, New York University, New York, NY, and Institut Straumann, Basel, Switzerland. §Professor and Head, Department of Periodontology, Faculty of Dental surgery, (Inserm U791/UIC 11) CHU de Nantes, Nantes, France. ¶Associate Professor and Head, Department of Oral Implantology, Faculty of Dental Surgery, University of Nantes, Nantes, France.

Purpose: Implant-supported prosthetic rehabilitations are in constant augmentation in everyday dental practice. This is largely due to increasing demand from patients for fixed or implant-stabilized prosthesis, although they are frequently reticent to complex preimplant bone augmentation surgeries, whenever bone volume is lacking. Narrow-diameter implants (NDI; ≤3.5 mm) have been developed to offer relatively simple implant solutions in challenging bone-deficient sites. However, concerns regarding their mechanical properties have been raised. Special titanium-zirconium material (Ti-Zr), with superior mechanical resistance, compared with pure titanium alloys has been introduced into the market. The purpose of this systematic review was to determine the available data on clinical performance of Ti-Zr NDI.

Materials And Methods: A literature search of all available clinical articles dealing with Ti-Zr NDI has been carried out. After including only prospective clinical trials, 14 papers were retrieved for thorough reviewing.

Conclusion: Short-term results from preliminary clinical reports are quite promising, although the number of published studies and the follow-up periods are still insufficient to determine the real benefit of this hybrid material compared with titanium, especially when using NDI.
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http://dx.doi.org/10.1097/ID.0000000000000557DOI Listing
April 2017

A Comparison of Tapered and Nontapered Implants in the Minipig.

Int J Oral Maxillofac Implants 2016 Nov/Dec;31(6):1341-1347

Purpose: Tapered implants are thought to result in equivalent long-term stability and marginal peri-implant bone height in comparison to cylindrical implants. The goal of this study was to compare the primary stability and osseointegration of a novel bone-level tapered-wall implant to a control bone-level cylindrical implant with exactly the same surface characteristics, in a direct side-by-side comparison in an animal model.

Materials And Methods: Mandibular premolars and first molars were extracted in 11 G.ttingen minipigs, and healing was allowed for 3 months. Six implants were placed with a 4-week surgical lag time between hemimandibles (three per side), and either immediately loaded (first implantation time point) or submerged (second implantation time point). Eight-mm-long × 4.1-mm-diameter titanium screw-type bone-level implants with tapered (two per side) and cylindrical bodies (one per side) were used (Institut Straumann); insertion torque and implant stability were measured, and the soft tissue was closed. Standardized radiographs were taken at implant placement and at sacrifice. Following a healing period of 1 month from the last surgical intervention (8 weeks total healing time for loaded implants; 4 weeks total healing time for nonloaded implants), the animals were sacrificed and mandibular blocks were harvested for nondecalcified histologic and histomorphometric analysis.

Results: All implants were integrated radiographically and osseointegrated histologically. Maximum insertion torque measurements and implant stability quotient values showed no significant difference between tapered and cylindrical implants. Histomorphometric analysis also resulted in comparable bone-to-implant contact values between the implant types and similarly limited marginal peri-implant bone resorption; no significant differences were observed regarding all the evaluated parameters between the groups, regardless of the loading regime.

Conclusion: In a direct side-by-side comparison, in an intraoral minipig model, a novel bone-level tapered screw implant with an SLActive surface showed comparable clinical and histologic outcomes to a parallel-walled bone-level screw implant with an SLActive surface.
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http://dx.doi.org/10.11607/jomi.4712DOI Listing
March 2017

Effect of tyrosine-rich amelogenin peptide on behavior and differentiation of endothelial cells.

Clin Oral Investig 2016 Nov 12;20(8):2275-2284. Epub 2016 Feb 12.

Division of Conservative Dentistry and Periodontology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.

Background: Enamel matrix derivative (EMD) is an effective biomaterial for periodontal tissue regeneration and might stimulate angiogenesis. Tyrosine-rich amelogenin peptide (TRAP) is present in EMD and is thought to contribute in its biological activity. In the present study, we investigated the effect of chemically synthesized TRAP on proliferation, migration, angiogenic structure formation, and differentiation of human umbilical vein endothelial cells (HUVECs) in vitro.

Material And Methods: The effects of TRAP isolated from EMD and chemically synthesized TRAP on proliferation/viability, migration, and angiogenic structure formation were investigated. Expression of angiopoietin-2 (ang-2), von Willebrand factor (vWF), E-selectin, intracellular adhesion molecules 1 (ICAM-1), vascular endothelial growth factor (VEGF) receptors FMS-like tyrosine kinase 1 (FLT-1), and kinase insert domain receptor (KDR) was measured on both messenger RNA (mRNA) and protein levels.

Results: The proliferation/viability of HUVECs was inhibited by TRAP at concentration of 100 μg/ml and slightly stimulated by EMD at similar concentration. Both EMD and TRAP stimulated endothelial cell migration in microchemotaxis chamber. The effect of both TRAP preparations on the migration was significantly higher than that of EMD. All substances stimulated formation of angiogenic structure in vitro. The expression of ICAM-1, E-selectin, FLT-1, KDR, and vWF was significantly increased by both TRAP and EMD at a concentration 50 μg/ml. The expression of ang-2 was not affected by TRAP but was significantly increased by EMD.

Conclusion: Our in vitro study shows that TRAP confer the most effects of EMD on the endothelial cells.

Clinical Relevance: TRAP might be used as a basis for development of new approaches for periodontal regeneration.
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http://dx.doi.org/10.1007/s00784-016-1726-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5069334PMC
November 2016

Osteoinductive potential of 4 commonly employed bone grafts.

Clin Oral Investig 2016 Nov 27;20(8):2259-2265. Epub 2016 Jan 27.

The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, People's Republic of China.

Objectives: Guided bone regeneration (GBR) aims to predictably restore missing bone that has been lost due to trauma, periodontal disease or a variety of systemic conditions. Critical to this procedure is the ability of a bone grafting material to predictably serve as a 3-dimensional scaffold capable of inducing cell and bone tissue in-growth at the material surface. Although all bone grafts are osteoconductive to bone-forming osteoblasts, only a small number of commercially available bone grafts with FDA approval are osteoinductive including demineralized freeze-dried bone allographs (DFDBA) and scaffolds containing bone morphogenetic proteins (BMPs). Recently, a class of synthetic bone grafts fabricated from biphasic calcium phosphate (BCP) sintered at a low temperature have been shown to form ectopic bone formation in non-skeletal sites without the use of growth factors. Therefore, the present study aimed to compare the osteoinductive potential of this group of synthetic BCP alloplasts with autografts, allografts and xenografts.

Materials And Methods: In the present study, 4 types of bone grafting materials including autogenous bone harvested with a bone mill, DFDBA (LifeNet, USA), a xenograft derived from bovine bone mineral (NBM, BioOss, Geistlich, Switzerland) and a novel synthetic biphasic calcium phosphate (BCP, Straumman, Switzerland) were implanted into intramuscular pouches of 24 rats and analysed histologically for their ability to form ectopic bone formation around grafting particles. A semi-quantitative osteoinductive score was used to quantify the osteoinductive ability of each bone graft.

Results: The results from the present study reveal that (1) autogenous bone resorbed rapidly in vivo, (2) the xenograft showed no potential to form ectopic bone formation and (3) both DFDBA and BCP were able to stimulate ectopic bone formation.

Conclusion: These studies demonstrate that these newly developed synthetic bone grafts have potential for inducing ectopic bone formation similar to DFDBA. Future clinical testing is necessary to reveal their bone-inducing properties in clinical scenarios including GBR procedures and in combination with implant dentistry.

Clinical Relevance: Novel BCP scaffolds are able to induce ectopic bone formation without the use of osteoinductive growth factors such as BMP2 and thus demonstrate a large clinical possibility to further enhance bone formation for a variety of clinical procedures.
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http://dx.doi.org/10.1007/s00784-016-1724-4DOI Listing
November 2016

A randomized, 12-month controlled trial to evaluate non-inferiority of early compared to conventional loading of modSLA implants in single tooth gaps.

Int J Implant Dent 2016 Dec 4;2(1):10. Epub 2016 Apr 4.

Tokyo Medical and Dental University, Tokyo, Japan.

Background: The aim of the study was to evaluate whether early loading of implants with a chemically modified sandblasted, large-grit, acid-etched (SLA) (SLActive®) surface was non-inferior to conventional loading in terms of change in crestal bone level.

Methods: This was a randomized, controlled, multicenter study. Patients requiring single-tooth rehabilitation in the posterior maxilla or mandible received implants and were randomized to receive a provisional restoration in occlusal load after 25 ± 3 days (early loading) or after 13 ± 1 weeks (conventional loading). The primary endpoint was change in crestal bone level between implant placement (baseline) and 6 months. Secondary endpoints included change in crestal bone level between baseline and 12 months, implant survival and success rates, and patient satisfaction.

Results: Of the 84 patients enrolled, 78 received implants and were randomized onto the early loading (41 patients) and conventional loading (37 patients) groups. The mean change in crestal bone level between baseline and 6 months was 0.56 ± 0.58 and 0.51 ± 0.62 mm for early and conventional loading, respectively; at 12 months, the mean change was 0.76 ± 0.60 and 0.73 ± 0.77 mm, respectively. Implant survival and success at 12 months were 100 % for both groups. Patient satisfaction was similar between the groups, except that more patients in the early loading group were satisfied or highly satisfied with the time taken for fitting.

Conclusion: The study demonstrated that early implant loading was non-inferior to conventional implant loading in terms of crestal bone level change in a Japanese patient population in short follow-up period and single tooth gaps in molar regions.
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http://dx.doi.org/10.1186/s40729-016-0040-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5005762PMC
December 2016

Dimensional Changes Following Immediate and Delayed Implant Placement: A Histomorphometric Study in the Canine.

Int J Oral Maxillofac Implants 2017 May/June;32(3):541–546. Epub 2016 Oct 14.

Purpose: The placement of immediate implants has become a routine treatment modality for the replacement of missing teeth. The aim of the present study was to evaluate dimensional changes of hard tissues following tooth extraction, implant bed preparation, and the subsequent integration of titanium implants placed immediately or following an 8-week healing period.

Materials And Methods: All mandibular premolars were extracted and used as experimental sites in five beagle dogs. The left quadrant was used to compare the healing of alveolar bone following regular tooth extraction or surgical implant bed preparation. The right quadrant was used to compare immediate with delayed implant placement (3.3 mm, Bone Level SLActive, Roxolid, Straumann) after an 8-week healing period. All samples were assessed histologically for new bone area/total area (BATA), bone-to-implant contact (BIC), and bone height changes from the buccal and lingual midlines.

Results: Implant bed preparation led to significantly lower BATA values and bone height loss compared with regular extraction sockets (-2.46 mm vs -1.44 mm, respectively; P = .0007). Placement of immediate implants demonstrated buccal and lingual bone height loss of 1.51 mm and 0.91 mm, respectively, whereas only 0.12 mm and 0.12 mm of bone height loss was observed during delayed implant placement. A significantly higher BIC was observed for implants placed immediately compared with delayed placement (52% vs 35%, P < .05).

Conclusion: Implant bed preparation further increased dimensional changes when compared with routine extraction sockets. Although immediate implant placement produced better BIC than did delayed placement, a significantly higher bone height loss at both the buccal and lingual midlines was reported. Further investigation is underway to minimize dimensional changes following immediate implant placement.
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http://dx.doi.org/10.11607/jomi.5145DOI Listing
October 2016

Chemically modified titanium-zirconium implants in comparison with commercially pure titanium controls stimulate the early molecular pathways of bone healing.

Clin Oral Implants Res 2017 Oct 16;28(10):1234-1240. Epub 2016 Aug 16.

Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.

Objectives: Titanium-zirconium (TiZr) has been proposed as a mechanically stronger alternative to commercially pure titanium for oral and orthopaedic implants. However, not much is known on the osseointegration kinetics of TiZr surfaces. In this study, we aimed to identify the genetic response of bone around TiZr implants compared to pure Ti.

Material And Methods: Microtextured and hydrophilic TiZr implants (tests) and cpTi implants grade IV (controls) were placed in the tibia of 30 New Zealand white rabbits. At 2, 4 and 12 weeks, the implants were subjected to removal torque test (RTQ). The expression of a panel of genes involved in the process of osseointegration was measured in the bone around the test and control implants by means of quantitative real-time polymerase chain reaction (PCR) and compared to the control samples.

Results: The controls yielded statistically significant higher RTQ at 4 weeks, but the RTQ of the tests had a larger increase between 4 and 12 weeks, when both groups reached similar values. The gene expression analysis showed that all selected markers for bone formation, bone remodelling and cytokines were significantly upregulated around TiZr implants after 2 weeks. After 4 weeks of healing, two bone formation markers were significantly more expressed in the test samples, while at 12 weeks, the expression of all genes was similar in the two groups.

Conclusions: TiZr implants showed comparable biomechanical outcomes to cpTi up to 12 weeks of healing. However, at early healing stages, they showed a significant upregulation of osteogenesis and osteoclastogenesis markers.
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http://dx.doi.org/10.1111/clr.12947DOI Listing
October 2017

A novel suturing approach for tissue displacement within minimally invasive periodontal plastic surgery.

Clin Case Rep 2016 Aug 23;4(8):831-7. Epub 2016 Jul 23.

College of Dentistry New York University New York City New York.

This paper describes a novel suturing approach that achieves harmonious and atraumatic soft tissue displacement in periodontal plastic surgery and soft tissue management around implants. The technique relies on a combination of horizontal and vertical mattress that are anchored at the splinted incisal contact points.
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http://dx.doi.org/10.1002/ccr3.582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4974440PMC
August 2016

Mechanical and chemical implant decontamination in surgical peri-implantitis treatment: preclinical "in vivo" study.

J Clin Periodontol 2016 08 13;43(8):694-701. Epub 2016 Jun 13.

Periodontology Unit, School of Medicine and Dentistry, University of Santiago de Compostela, Santiago de Compostela, Spain.

Objective: The aim of the present study was to evaluate the effect of a titanium brush and chemical agents following surgical treatment of experimental peri-implantitis.

Material And Methods: Six implants were installed in the mandible of eight beagle dogs (unit of analysis) 3 months after tooth extraction. Experimental peri-implantitis was induced 3 months later. The defects were randomly allocated in three treatment groups: (a) TiBrush(™)  + sodium hypochlorite + chlorhexidine (TBH), (b) TiBrush(™)  + chlorhexidine (TB), (c) an ultrasonic device + chlorhexidine (US). The distal implant in each hemimandible was used as control, and no treatment was done. Clinical and histological measurements were performed after 3 months of healing.

Results: All treatment procedures resulted in statistically significant improvements of all clinical parameters. Histomorphometrical analysis revealed no statistically significant differences between treatment groups in terms of woven bone height (primary outcome). However, there were differences between test and control groups in terms of inflammation, bone defect depth and bone refill without differences between TBH and TB groups.

Conclusions: Resolution of peri-implantitis after access surgery and decontamination of peri-implant surfaces with TiBrush(™) with or without sodium hypochlorite is possible. However, the concomitant use of sodium hypochlorite has minor effect on treatment outcomes.
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http://dx.doi.org/10.1111/jcpe.12566DOI Listing
August 2016

Runx2/DICER/miRNA Pathway in Regulating Osteogenesis.

J Cell Physiol 2017 01 26;232(1):182-91. Epub 2016 Apr 26.

Division of Oral Biology, Tufts University School of Dental Medicine, Boston, Massachusetts.

DICER is the central enzyme that cleaves precursor microRNAs (miRNAs) into 21-25 nucleotide duplex in cell lineage differentiation, identity, and survival. In the current study, we characterized the specific bone metabolism genes and corresponding miRNAs and found that DICER and Runt-related transcription factor 2 (Runx2) expressions increased simultaneously during osteogenic differentiation. Luciferase assay showed that Runx2 significantly increased the expression levels of DICER luciferase promoter reporter. Our analysis also revealed weaker DICER expression in embryos of Runx2 knock out mice (Runx2 -/-) compared with that of Runx2 +/- and Runx2 +/+ mice. We further established the calvarial bone critical-size defect (CSD) mouse model. The bone marrow stromal cells (BMSCs) transfected with siRNA targeting DICER were combined with silk scaffolds and transplanted into calvarial bone CSDs. Five weeks post-surgery, micro-CT analysis revealed impaired bone formation, and repairing in calvarial defects with the siRNA targeting DICER group. In conclusion, our results suggest that DICER is specifically regulated by osteogenic master gene Runx2 that binds to the DICER promoter. Consequently, DICER cleaves precursors of miR-335-5p and miR-17-92 cluster to form mature miRNAs, which target and decrease the Dickkopf-related protein 1 (DKK1), and proapoptotic factor BIM levels, respectively, leading to an enhanced Wnt/β-catenin signaling pathway. These intriguing results reveal a central mechanism underlying lineage-specific regulation by a Runx2/DICER/miRNAs cascade during osteogenic differentiation and bone development. Our study, also suggests a potential application of modulating DICER expression for bone tissue repair and regeneration. J. Cell. Physiol. 232: 182-191, 2017. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jcp.25406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5028245PMC
January 2017

Twenty years of enamel matrix derivative: the past, the present and the future.

J Clin Periodontol 2016 08 28;43(8):668-83. Epub 2016 May 28.

Department of Periodontology, University of Bern, Bern, Switzerland.

Bacground: On June 5th, 2015 at Europerio 8, a group of leading experts were gathered to discuss what has now been 20 years of documented evidence supporting the clinical use of enamel matrix derivative (EMD). Original experiments led by Lars Hammarström demonstrated that enamel matrix proteins could serve as key regenerative proteins capable of promoting periodontal regeneration including new cementum, with functionally oriented inserting new periodontal ligament fibres, and new alveolar bone formation. This pioneering work and vision by Lars Hammarström has paved the way to an enormous amount of publications related to its biological basis and clinical use. Twenty years later, it is clear that all these studies have greatly contributed to our understanding of how biologics can act as mediators for periodontal regeneration and have provided additional clinical means to support tissue regeneration of the periodontium.

Aims: This review article aims to: (1) provide the biological background necessary to understand the rational for the use of EMD for periodontal regeneration, (2) present animal and human histological evidence of periodontal regeneration following EMD application, (3) provide clinically relevant indications for the use of EMD and (4) discuss future avenues of research including key early findings leading to the development of Osteogain, a new carrier system for EMD specifically developed with better protein adsorption to bone grafting materials.
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http://dx.doi.org/10.1111/jcpe.12546DOI Listing
August 2016

Histological assessment of hard and soft tissues surrounding a novel ceramic implant: a pilot study in the minipig.

J Clin Periodontol 2016 06 2;43(6):538-46. Epub 2016 May 2.

Periodontology Unit, School of Medicine and Dentistry, University of Santiago de Compostela, Santiago de Compostela, Spain.

Objective: The aim of this study was to investigate clinical and soft/hard tissues histomorphological outcomes of a ceramic implant comparatively to a titanium implant in a minipig model.

Material And Methods: Eighteen soft tissue level implants (9 Ceramic with ZLA(®) surface as test, and 9 titanium SLActive(®) as control, Institut Straumann, Basel, Switzerland) were randomly placed into the mandible of 6 minipigs (n = 6). Two months later, animals were sacrificed and block biopsies were obtained to assess histomorphological outcomes. Unadjusted paired comparisons, of both groups were performed using the Wilcoxon signed rank test. The Dunnett-Hsu test was used to adjust for multiple comparisons.

Results: All implants showed excellent integration into bone and soft tissue. The fBIC (distance implant shoulder to most coronal implant contact) and BIC% (percentage bone-to-implant contact) were for both groups; test: 3.95 mm and 85.4%; control 3.97 mm and 84.3% respectively. No difference in peri-implant mucosa height was found, however, the sulcular epithelium was significantly shorter for the ZrO2 (mean: 0.76, 95%CI: 0.46-1.06) than for the Ti (mean: 1.40, 95%CI: 1.10-1.70) (p = 0.0090).

Conclusions: Within the limits of this pilot study, no difference was found between the ceramic implant with ZLA(®) surface and a titanium implant in terms of bone tissue integration. Furthermore, the epithelial attachment favoured this ceramic implant over titanium.
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http://dx.doi.org/10.1111/jcpe.12543DOI Listing
June 2016