Review
Introduction
Methods
Study design
Inclusion and exclusion criteria
Search strategy
Study selection
Data extraction
Assessment of methodology and risk of bias
Methodology
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Tissue harvesting | Tissue attached to implant carefully removed with a curette, preexisting hard tissue discarded | Tissue attached to implant carefully removed with a curette and homogenized | Implants removed by reverse threading and homogenized; cell lysates isolated | Implants removed by reverse threading and homogenized; cell lysates isolated |
Sample preparation | Total RNA isolation, purification, quantity/quality analysis and biotin-labeling | Total RNA isolation, purification, quantity/quality analysis and biotin-labeling | Total RNA isolation, quantification | Total RNA isolation, purification, quantity/quality analysis and biotin-labeling |
Array technique | Microarray hybridization (Human WG-6 V3) | Microarray hybridization (Human WG-6 V3) | RT-PCR (custom RT-PCR array for osteogenesis genes; human inflammatory cytokines and receptors PCR array) | Microarray hybridization (Affymetrix Human Gene 1.1 ST) |
Scanning, data preparation | Bead Station 500/Bead Studio v3 software, raw probe expression values extracted | Bead Station 500/ Bead Studio v3 software, raw probe expression values extracted | RT2 SYBR Green qPCR Master Mix/7500 Real-Time PCR system | Affymetrix Gene Chip Scanner |
Processing | Noisy data discarded | Noisy data discarded | Normalization of osteogenesis and cytokine array | Unclear |
Clustering | GO categories (DAVID tool) | GO categories (DAVID tool) | Osteogenesis genes; cytokine-related genes | GO categories (Gene Spring) |
Statistical analysis | Gene Spring software | Gene Spring software | RT2 Profiler software | Gene Spring software |
Comparisons | Pair-wise comparisons between three time points (4 vs. 7 days, 7 vs. 14 days, and 4 vs. 14 days) | Pair-wise comparisons at each time point (4, 7, and 14 days) between SLA and SLActive surfaces | T-test to evaluate differences between each implant surface per time point | Two-way ANOVAs to determine differences between implant surface type and time points; pair-wise comparisons of each implant surface independently at different time points (day 7 vs. day 3) |
Category
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Study design | ||||
Comparison | None (only SLActive) | SLA vs. SLActive | TiOBlast vs. Osseospeed | TiOBlast vs. Osseospeed |
Setting | University | University | University | University |
Population, inclusion criteria | 9 healthy volunteers with no mandibular third molars, no contraindications for oral surgery; age 21 to 48, median 29 years | 9 healthy volunteers with no mandibular third molars; age 21 to 48, median 29 years | 6 women, 4 men; implant patients, systemically healthy (no HTN, diabetes, CVD); age 25 to 58, mean 36.2 years | 9 women, 2 men; implant patients, systemically healthy; age 47 to 69, mean 60.2 years |
Exclusion criteria | Smokers | Smokers | Smokers, pregnancy, periodontal/periapical disease, subjects taking bisphosphonates, hormone replacement therapy, corticosteroids | Smokers, uncontrolled diabetes, history of head/neck radiotherapy, taking corticosteroids, bisphosphonates |
Comparability of groups | Unclear | Unclear | Unclear | Unclear |
Potential confounders, e.g., post-op medication | Unclear | Unclear | Unclear | Unclear |
Power calculation | No | No | No | No |
Statistical correction | For multiple sampling | For multiple sampling | Unclear | For multiple sampling |
Methods | ||||
Tissue analyzed | Peri-implant tissue | Peri-implant tissue | Implant-adherent cells | Implant-adherent cells |
Genetic material analyzed | Total RNA | Total RNA | Total RNA | Total RNA |
Success rate | Unclear | 16/18 samples (88.8%) | 7/10 subject samples (70%) | Unclear |
Genotyping method | Microarray | Microarray | RT-PCR | Whole-genome microarray |
Genotype counts | Yes | Yes | Yes | Yes |
Blinding | Unclear | Unclear | Yes | Unclear |
Reproducibility, validated genotyping accuracy | No | No | No | No |
Results and discussion
Search results and study characteristics
Study
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Design | 9 patients; 9 implants placed | 18 patients; 18 implants placed | 10 patients; 60 implants placed | 11 patients; 44 implants placed |
Total RNA extracted from peri-implant tissue (trephine) | 16 samples analyzed | 42 samples analyzed | Total RNA extracted from implant adherent cells (reverse thread) | |
Total RNA extracted from peri-implant tissue (trephine) | Total RNA extracted from implant adherent cells (reverse thread) | |||
Surface | SLActive | SLA vs. SLActive | TiOBlast vs. Osseospeed | TiOBlast vs. Osseospeed |
GE day 3/4 | Upregulated | Upregulated on SLA | Upregulated on both surfaces | No significant differences between surfaces at any time point (P > 0.05) |
CKs (TNF-a, IL-6, IL-2) | Neurogenesis | Osteogenesis (Runx2, Osx, BMP6, OPN) | Results presented as GE at day 7 vs. day 3 for each surface | |
Immune-inflammatory cells (LC, MP) | Collagen organization | Inflammatory CKs (IL-1A,B, TNF) | ||
Inflammatory NF-kB p/w | Upregulated on SLActive | MP activity | ||
Ras protein p/w | Upregulated on Osseospeed | |||
Collagen organization | Chemotaxis (CCL18, CXCL10, CXCL14) | |||
CK response | Anti-inflammatory CKs (TOLLIP, IL9, IL22) | |||
GE day 7
| Upregulated | Upregulated on both surfaces | Upregulated on both surfaces | Upregulated on both surfaces |
MSC genes (HOX, Sp3) | Inflammatory CKs (IL1, IL2, IL6, TNFS) | Osteogenesis (Runx2, Osx*, OCN*, OPN, BMP6, BSP) | ECM (Coll, GPs, PGs) | |
GF (TGF-B receptor) | Neurogenesis | [* Osseo > TiOB; P < 0.05] | Collagen organization (PLODs, LOX, PCOLCE) | |
VEGF sig. (vs. day 14) | Upregulated on SLActive | Angiogenesis/VEGF sig. (ANXA, EPAS1) | ||
Wnt p/w | Neurogenesis (BDNF, NTF3) | Ossification | ||
Downregulated | ECM (OPN) | Remodeling (MMPs, TIMPs) | ||
Inflammatory NF-kB p/w (vs. day 4) | BMP p/w (BMP4, BMP2K) | Osteoclastic (CTSK, ACP5) | ||
MAPK sig. | Chemotaxis (CKs, MP activity) | |||
Mineralization | Anti-inflammatory CKs (CCL22, CCL18) | |||
Focal adhesion (integrins) | Downregulated on both surfaces | |||
Angiogenesis (VEGF sig., P13-Akt p/w) | Inflammatory CKs (IL1A, IL1B) | |||
Downregulated on SLActive | ||||
Inflammatory cells (LC) | ||||
GE day 14 | Upregulated | Upregulated on both surfaces | - | |
ECM (Coll, OC, ON, ALP) | BMP p/w (BMP4, BMP2K) | |||
TFs (Osx, Dlx5, Twist1, Smad6) | Downregulated on both surfaces | |||
Remodeling (MMP, CTSK) | Inflammatory cells (LC) | |||
GFs (BMP, GDF) | ||||
Angiogenesis (VEGF sig.) | ||||
Neurogenesis | ||||
TGF-b/BMP, Notch p/w | ||||
Ras protein p/w | ||||
Wnt-receptor genes | ||||
Notch genes (up/down) | ||||
Downregulated | ||||
Inflammatory response (vs. day 7) |
Assessment of methodology and risk of bias
Biological processes identified through gene expression in peri-implant tissues
Process
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Upregulated genes
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Category (gene code)
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Inflammation/immune response | |
Pro-inflammatory cytokines | Tumor necrosis factor (TNF-a, TNFSF9) |
Interleukin (IL-6, IL-2, IL-1 F9, IL-23A, IL-6ST) | |
Interferon (IFNA2) | |
Nuclear factor-kB (I-kB kinase/NF-kB) | |
Anti-inflammatory cytokines | Interleukin (IL-22, IL-9) |
Toll interacting protein (TOLLIP) | |
Cells | Lymphocyte, macrophage negative proliferation (BTLA, LST1) |
Macrophage scavenger receptor (MSR1) | |
Chemotaxis | Chemokines (CCR8, CCL18, CCL22, CXCL10, CXCL14) |
Osteoinduction/osteogenesis | |
Growth factors (GF)/signaling pathways | Insulin-like GF (IGF1) |
Transforming GF (TGF-b, TGF-b receptor 1, 2 and 3, TGF-a) | |
Platelet-derived GF (PDGF receptor) | |
Bone morphogenetic proteins (BMP4, BMP6, BMP receptor 1A, BMP2-K) | |
Growth and differentiation factor (GDF10) | |
Wnt frizzled receptor (FZD3, FZD8, FRZB) | |
Notch (NOTCH2) | |
Ras-protein signal transduction (RAP1B, RAP1A, RASGRP4) | |
Mitogen activated protein kinase (MAP3K7IP2, MAPK9, MAP2K3, MAP3K2) | |
Transcription factors | ‘Master switches’ [RUNX2, SP7 (OSX)] |
Homeobox (DLX1, DLX5, HOXD12, MSX1, HOXA5, HOXB1, HOXB6, HOXC6) | |
SP [SP1, SP3, SP7 (Osx)] | |
Twist (TWIST 1-receptor) | |
ECM deposition/organization | Collagen (Col1A1, Col12A1, Col6A3, Col3A1, Col6A1, Col11A1, Col11A2, Col13A1, Col5A2) |
Non-collagen proteins [BGLAP (OC), SPARC (ON), SPP1 (OP), BSP, IBSP, POSTN, ECM1] | |
Small leucine-rich proteoglycans (SLRP) (DCN, BGN, LUM) | |
Heat-shock protein 47 (HSP47) | |
Alkaline phosphatase (ALPL) | |
Cadherin (CDH11) | |
Integrin (ITGB4, ITGB5) | |
Laminin (LAMA2, LAMA3) | |
Pro-collagen lysyl-hydroxylase (PLOD1, PLOD2, PLOD3) | |
Pro-collagen C-endopeptidase enhancer (PCOLCE) | |
Lysyl-oxidase (LOX) | |
Osteoclast activity/remodeling | Cathepsin K (CTSK, CTSK-receptor) |
Tartarate-resistant acid phosphatase (TRAP/ACP5) | |
Matrix metallopeptidase (MMP2, MMP12, MMP9, MMP7, MMP13) | |
Tissue inhibitor metallopeptidase (TIMP2, TIMP3) | |
Angiogenesis | Vascular endothelial GF-signaling (EPAS1, ANXA2, EGR1-binding protein) |
Phosphatidyl-inositol 3-kinase (PI3K)-Akt signaling | |
Neurogenesis | Brain-derived neurotrophic factor (BDNF) |
Neurotrophin 3 (NTF3) | |
NK2 homeobox 2(NKX2-2) | |
Tubby-like protein 3 (TULP3) |